Science.gov

Sample records for itunes live streaming

  1. ATLAS Live: Collaborative Information Streams

    NASA Astrophysics Data System (ADS)

    Goldfarb, Steven; ATLAS Collaboration

    2011-12-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using digital signage software. The system is robust and flexible, utilizing scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intra-screen divisibility. Information is published via the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video tool. Authorisation is enforced at the level of the streaming and at the web portals, using the CERN SSO system.

  2. Podcasting for Language Learning through iTunes U: The Learner's View

    ERIC Educational Resources Information Center

    Rosell-Aguilar, Fernando

    2013-01-01

    iTunes U has become the main worldwide provider of educational podcasts but, despite its popularity, little is known about the type of user who downloads iTunes U language resources, or how those resources are used. This paper presents the results of the first major survey (1891 responses) of users of one of the most successful iTunes U content…

  3. iTunes U: An Opportunity for Students

    ERIC Educational Resources Information Center

    Germany, Lisa

    2011-01-01

    Purpose: The aim of this paper is to demonstrate that, with a bit of creative thinking, elements of certain university-wide projects (in this case study, establishing an iTunes U site) can be incorporated into student studies and assessment as real-world learning opportunities. Design/methodology/approach: Describes three different approaches…

  4. Supporting Seamless Mobility for P2P Live Streaming

    PubMed Central

    Kim, Eunsam; Kim, Sangjin; Lee, Choonhwa

    2014-01-01

    With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme. PMID:24977171

  5. Supporting seamless mobility for P2P live streaming.

    PubMed

    Kim, Eunsam; Kim, Sangjin; Lee, Choonhwa

    2014-01-01

    With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme. PMID:24977171

  6. Live HDR video streaming on commodity hardware

    NASA Astrophysics Data System (ADS)

    McNamee, Joshua; Hatchett, Jonathan; Debattista, Kurt; Chalmers, Alan

    2015-09-01

    High Dynamic Range (HDR) video provides a step change in viewing experience, for example the ability to clearly see the soccer ball when it is kicked from the shadow of the stadium into sunshine. To achieve the full potential of HDR video, so-called true HDR, it is crucial that all the dynamic range that was captured is delivered to the display device and tone mapping is confined only to the display. Furthermore, to ensure widespread uptake of HDR imaging, it should be low cost and available on commodity hardware. This paper describes an end-to-end HDR pipeline for capturing, encoding and streaming high-definition HDR video in real-time using off-the-shelf components. All the lighting that is captured by HDR-enabled consumer cameras is delivered via the pipeline to any display, including HDR displays and even mobile devices with minimum latency. The system thus provides an integrated HDR video pipeline that includes everything from capture to post-production, archival and storage, compression, transmission, and display.

  7. Promoting the Library's CD Collection via iTunes File Sharing

    ERIC Educational Resources Information Center

    Connolly, Bruce

    2005-01-01

    One of the hippest things staff can do with technology, is to use it to meet students on their own turf. As part of an outreach effort, one group of librarians at Union College's Schaffer Library (Schenectady, NY) started sharing its vast CD collection via iTunes. They were trying to show college students that there was a lot to discover at the

  8. Evaluation of iTunes University Courses through Instructional Design Strategies and m-Learning Framework

    ERIC Educational Resources Information Center

    Tseng, Hung Wei; Tang, Yingqi; Morris, Betty

    2016-01-01

    As mobile learning technology promotes learning accessibility and flexibility, students benefit from social interactivity and connective learning process which will also foster students' performance and satisfaction on learning content. The primary purpose of this research was to evaluate iTunes U courses based on instructional design strategies

  9. Evaluation of iTunes University Courses through Instructional Design Strategies and m-Learning Framework

    ERIC Educational Resources Information Center

    Tseng, Hung Wei; Tang, Yingqi; Morris, Betty

    2016-01-01

    As mobile learning technology promotes learning accessibility and flexibility, students benefit from social interactivity and connective learning process which will also foster students' performance and satisfaction on learning content. The primary purpose of this research was to evaluate iTunes U courses based on instructional design strategies…

  10. Research and design of a new model for P2P live streaming system

    NASA Astrophysics Data System (ADS)

    Li, Ying; Yang, Lijuan; Liu, Haiyan

    2013-07-01

    According to the research and analysis of typical models for P2P (Peer to Peer) live streaming system, we overview and summarize the strengths and weaknesses of existing technologies. This paper proposes a new model for P2P live streaming system, which used a scheme combining unicast and multicast trees, and analysis the strategy of node management. The model combines advantages of easy maintenance of unicast tree and load balancing of multicast tree, and enhances the availability, stability and quality of service for live streaming system.

  11. An immersive surgery training system with live streaming capability.

    PubMed

    Yang, Yang; Guo, Xinqing; Yu, Zhan; Steiner, Karl V; Barner, Kenneth E; Bauer, Thomas L; Yu, Jingyi

    2014-01-01

    Providing real-time, interactive immersive surgical training has been a key research area in telemedicine. Earlier approaches have mainly adopted videotaped training that can only show imagery from a fixed view point. Recent advances on commodity 3D imaging have enabled a new paradigm for immersive surgical training by acquiring nearly complete 3D reconstructions of actual surgical procedures. However, unlike 2D videotaping that can easily stream data in real-time, by far 3D imaging based solutions require pre-capturing and processing the data; surgical trainings using the data have to be conducted offline after the acquisition. In this paper, we present a new real-time immersive 3D surgical training system. Our solution builds upon the recent multi-Kinect based surgical training system [1] that can acquire and display high delity 3D surgical procedures using only a small number of Microsoft Kinect sensors. We build on top of the system a client-server model for real-time streaming. On the server front, we efficiently fuse multiple Kinect data acquired from different viewpoints and compress and then stream the data to the client. On the client front, we build an interactive space-time navigator to allow remote users (e.g., trainees) to witness the surgical procedure in real-time as if they were present in the room. PMID:24732560

  12. The phylogenetic structure of microbial biofilms and free-living bacteria in a small stream.

    PubMed

    Brablcov, Lenka; Burinkov, Iva; Badurov, Pavlna; Rulk, Martin

    2013-05-01

    The phylogenetic composition, bacterial biomass, and biovolume of both planktonic and biofilm communities were studied in a low-order Byst?ice stream near Olomouc City, in the Czech Republic. The aim of the study was to compare the microbial communities colonizing different biofilm substrata (stream aggregates, stream sediment, underwater tree roots, stream stones, and aquatic macrophytes) to those of free-living bacteria. The phylogenetic composition was analyzed using fluorescence in situ hybridization for main phylogenetic groups. All phylogenetic groups studied were detected in all sample types. The stream stone was the substratum where nearly all phylogenetic groups were the most abundant, while the lowest proportion to the DAPI-stained cells was found for free-living bacteria. The probe specific for the domain Bacteria detected 20.6 to 45.8% of DAPI-stained cells while the probe specific for the domain Archaea detected 4.3 to 17.9%. The most abundant group of Proteobacteria was Alphaproteobacteria with a mean of 14.2%, and the least abundant was Betaproteobacteria with a mean of 11.4%. The average value of the Cytophaga-Flavobacteria group was 10.5%. Total cell numbers and bacterial biomass were highest in sediment and root biofilm. The value of cell biovolume was highest in stone biofilm and lowest in sediment. Overall, this study revealed relevant differences in phylogenetic composition, bacterial biomass, and biovolume between different stream biofilms and free-living bacteria. PMID:23129136

  13. Adaptive live multicast video streaming of SVC with UEP FEC

    NASA Astrophysics Data System (ADS)

    Lev, Avram; Lasry, Amir; Loants, Maoz; Hadar, Ofer

    2014-09-01

    Ideally, video streaming systems should provide the best quality video a user's device can handle without compromising on downloading speed. In this article, an improved video transmission system is presented which dynamically enhances the video quality based on a user's current network state and repairs errors from data lost in the video transmission. The system incorporates three main components: Scalable Video Coding (SVC) with three layers, multicast based on Receiver Layered Multicast (RLM) and an UnEqual Forward Error Correction (FEC) algorithm. The SVC provides an efficient method for providing different levels of video quality, stored as enhancement layers. In the presented system, a proportional-integral-derivative (PID) controller was implemented to dynamically adjust the video quality, adding or subtracting quality layers as appropriate. In addition, an FEC algorithm was added to compensate for data lost in transmission. A two dimensional FEC was used. The FEC algorithm came from the Pro MPEG code of practice #3 release 2. Several bit errors scenarios were tested (step function, cosine wave) with different bandwidth size and error values were simulated. The suggested scheme which includes SVC video encoding with 3 layers over IP Multicast with Unequal FEC algorithm was investigated under different channel conditions, variable bandwidths and different bit error rates. The results indicate improvement of the video quality in terms of PSNR over previous transmission schemes.

  14. Using Text Mining to Uncover Students' Technology-Related Problems in Live Video Streaming

    ERIC Educational Resources Information Center

    Abdous, M'hammed; He, Wu

    2011-01-01

    Because of their capacity to sift through large amounts of data, text mining and data mining are enabling higher education institutions to reveal valuable patterns in students' learning behaviours without having to resort to traditional survey methods. In an effort to uncover live video streaming (LVS) students' technology related-problems and to…

  15. Using Text Mining to Uncover Students' Technology-Related Problems in Live Video Streaming

    ERIC Educational Resources Information Center

    Abdous, M'hammed; He, Wu

    2011-01-01

    Because of their capacity to sift through large amounts of data, text mining and data mining are enabling higher education institutions to reveal valuable patterns in students' learning behaviours without having to resort to traditional survey methods. In an effort to uncover live video streaming (LVS) students' technology related-problems and to

  16. Wireless live streaming video of laparoscopic surgery: a bandwidth analysis for handheld computers.

    PubMed

    Gandsas, Alex; McIntire, Katherine; George, Ivan M; Witzke, Wayne; Hoskins, James D; Park, Adrian

    2002-01-01

    Over the last six years, streaming media has emerged as a powerful tool for delivering multimedia content over networks. Concurrently, wireless technology has evolved, freeing users from desktop boundaries and wired infrastructures. At the University of Kentucky Medical Center, we have integrated these technologies to develop a system that can wirelessly transmit live surgery from the operating room to a handheld computer. This study establishes the feasibility of using our system to view surgeries and describes the effect of bandwidth on image quality. A live laparoscopic ventral hernia repair was transmitted to a single handheld computer using five encoding speeds at a constant frame rate, and the quality of the resulting streaming images was evaluated. No video images were rendered when video data were encoded at 28.8 kilobytes per second (Kbps), the slowest encoding bitrate studied. The highest quality images were rendered at encoding speeds greater than or equal to 150 Kbps. Of note, a 15 second transmission delay was experienced using all four encoding schemes that rendered video images. We believe that the wireless transmission of streaming video to handheld computers has tremendous potential to enhance surgical education. For medical students and residents, the ability to view live surgeries, lectures, courses and seminars on handheld computers means a larger number of learning opportunities. In addition, we envision that wireless enabled devices may be used to telemonitor surgical procedures. However, bandwidth availability and streaming delay are major issues that must be addressed before wireless telementoring becomes a reality. PMID:15458077

  17. Efficient Analysis of Live and Historical Streaming Data and itsApplication to Cybersecurity

    SciTech Connect

    Reiss, Frederick; Stockinger, Kurt; Wu, Kesheng; Shoshani, Arie; Hellerstein, Joseph M.

    2007-04-06

    Applications that query data streams in order to identifytrends, patterns, or anomalies can often benefit from comparing the livestream data with archived historical stream data. However, searching thishistorical data in real time has been considered so far to beprohibitively expensive. One of the main bottlenecks is the update costsof the indices over the archived data. In this paper, we address thisproblem by using our highly-efficient bitmap indexing technology (calledFastBit) and demonstrate that the index update operations aresufficiently efficient for this bottleneck to be removed. We describe ourprototype system based on the TelegraphCQ streaming query processor andthe FastBit bitmap index. We present a detailed performance evaluation ofour system using a complex query workload for analyzing real networktraffic data. The combined system uses TelegraphCQ to analyze streams oftraffic information and FastBit to correlate current behaviors withhistorical trends. We demonstrate that our system can simultaneouslyanalyze (1) live streams with high data rates and (2) a large repositoryof historical stream data.

  18. A Complexity-Aware Video Adaptation Mechanism for Live Streaming Systems

    NASA Astrophysics Data System (ADS)

    Lu, Meng-Ting; Yao, Jason J.; Chen, Homer H.

    2007-12-01

    The paradigm shift of network design from performance-centric to constraint-centric has called for new signal processing techniques to deal with various aspects of resource-constrained communication and networking. In this paper, we consider the computational constraints of a multimedia communication system and propose a video adaptation mechanism for live video streaming of multiple channels. The video adaptation mechanism includes three salient features. First, it adjusts the computational resource of the streaming server block by block to provide a fine control of the encoding complexity. Second, as far as we know, it is the first mechanism to allocate the computational resource to multiple channels. Third, it utilizes a complexity-distortion model to determine the optimal coding parameter values to achieve global optimization. These techniques constitute the basic building blocks for a successful application of wireless and Internet video to digital home, surveillance, IPTV, and online games.

  19. Occurrence of free-living amoebae in streams of the Mexico Basin.

    PubMed

    Bonilla-Lemus, Patricia; Caballero Villegas, Adn S; Carmona Jimnez, Javier; Lugo Vzquez, Alfonso

    2014-11-01

    Free-living amoebae (FLA) are protozoa that are widely distributed in nature. They are important in the cycling of nutrients in aquatic food chains, but their distribution in natural aquatic environments is not well known. We conducted a survey to determine the presence and distribution of FLA and their relation to some physicochemical parameters in streams of the Mexico Basin in Central Mexico. Thirty-two sites from 18 streams were sampled. Samples were centrifuged and cultured onto NNA-media to isolate amoebae. Identifications were based on morphology. The pathogenicity of Acanthamoeba isolates was tested. Oxygen saturation, temperature, pH, specific conductance, water flow, dissolved reactive phosphorus, nitrites, nitrates, ammonia, dissolved inorganic nitrogen and coliforms were determined. One hundred-and-twenty FLA representing 18 genera were identified. The most frequent genera were Vannella, Rosculus and Acanthamoeba. The frequency of potentially pathogenic FLA was low and only 3 Acanthamoeba isolates were invasive in mice. The highest species richness of FLA was found in streams located into agriculture activity areas and those close to small villages that discharge wastewater into them. Water temperatures were always below 17C. Oxygen saturation and pH were within the limits for the growth of most FLA. The presence of Acanthamoeba and Naegleria was low; nevertheless, they include potentially pathogenic species and can act as vectors and reservoirs for microbial pathogens and can produce human infections. PMID:25014111

  20. The role of the geophysical template and environmental regimes in controlling stream-living trout populations

    USGS Publications Warehouse

    Penaluna, Brooke E.; Railsback, Steve F.; Dunham, Jason B.; Johnson, S.; Bilby, Richard E.; Skaugset, Arne E.

    2015-01-01

    The importance of multiple processes and instream factors to aquatic biota has been explored extensively, but questions remain about how local spatiotemporal variability of aquatic biota is tied to environmental regimes and the geophysical template of streams. We used an individual-based trout model to explore the relative role of the geophysical template versus environmental regimes on biomass of trout (Oncorhynchus clarkii clarkii). We parameterized the model with observed data from each of the four headwater streams (their local geophysical template and environmental regime) and then ran 12 simulations where we replaced environmental regimes (stream temperature, flow, turbidity) of a given stream with values from each neighboring stream while keeping the geophysical template fixed. We also performed single-parameter sensitivity analyses on the model results from each of the four streams. Although our modeled findings show that trout biomass is most responsive to changes in the geophysical template of streams, they also reveal that biomass is restricted by available habitat during seasonal low flow, which is a product of both the stream’s geophysical template and flow regime. Our modeled results suggest that differences in the geophysical template among streams render trout more or less sensitive to environmental change, emphasizing the importance of local fish–habitat relationships in streams.

  1. Biology in focus: better lives through better science: new hope for acid streams

    USGS Publications Warehouse

    Watten, Barnaby

    1998-01-01

    Across the nation, a toxic pollutant turns clean streams orange, kills fish and plant life, and smells like rotten eggs. The culprit is acid mine drainage, the poisonous water leaking from more than 500,000 abandoned and inactive mines in 32 states. The toxic discharge is a problem for operational mines as well. In the Appalachian coal region, for example, acid mine drainage has degraded more than 8,000 miles of streams and has left some aquatic habitats virtually lifeless.

  2. Exploring a QoS Driven Scheduling Approach for Peer-to-Peer Live Streaming Systems with Network Coding

    PubMed Central

    Cui, Laizhong; Lu, Nan; Chen, Fu

    2014-01-01

    Most large-scale peer-to-peer (P2P) live streaming systems use mesh to organize peers and leverage pull scheduling to transmit packets for providing robustness in dynamic environment. The pull scheduling brings large packet delay. Network coding makes the push scheduling feasible in mesh P2P live streaming and improves the efficiency. However, it may also introduce some extra delays and coding computational overhead. To improve the packet delay, streaming quality, and coding overhead, in this paper are as follows. we propose a QoS driven push scheduling approach. The main contributions of this paper are: (i) We introduce a new network coding method to increase the content diversity and reduce the complexity of scheduling; (ii) we formulate the push scheduling as an optimization problem and transform it to a min-cost flow problem for solving it in polynomial time; (iii) we propose a push scheduling algorithm to reduce the coding overhead and do extensive experiments to validate the effectiveness of our approach. Compared with previous approaches, the simulation results demonstrate that packet delay, continuity index, and coding ratio of our system can be significantly improved, especially in dynamic environments. PMID:25114968

  3. Exploring a QoS driven scheduling approach for peer-to-peer live streaming systems with network coding.

    PubMed

    Cui, Laizhong; Lu, Nan; Chen, Fu

    2014-01-01

    Most large-scale peer-to-peer (P2P) live streaming systems use mesh to organize peers and leverage pull scheduling to transmit packets for providing robustness in dynamic environment. The pull scheduling brings large packet delay. Network coding makes the push scheduling feasible in mesh P2P live streaming and improves the efficiency. However, it may also introduce some extra delays and coding computational overhead. To improve the packet delay, streaming quality, and coding overhead, in this paper are as follows. we propose a QoS driven push scheduling approach. The main contributions of this paper are: (i) We introduce a new network coding method to increase the content diversity and reduce the complexity of scheduling; (ii) we formulate the push scheduling as an optimization problem and transform it to a min-cost flow problem for solving it in polynomial time; (iii) we propose a push scheduling algorithm to reduce the coding overhead and do extensive experiments to validate the effectiveness of our approach. Compared with previous approaches, the simulation results demonstrate that packet delay, continuity index, and coding ratio of our system can be significantly improved, especially in dynamic environments. PMID:25114968

  4. Application and Integration of Live Streaming from Leading Robotic Centres Can Enhance Surgical Education.

    PubMed

    Collins, Justin W; Verhagen, Harko; Mottrie, Alexander; Wiklund, Peter N

    2015-11-01

    Internet-based video-streaming enables us to share surgical knowledge and to study leading surgeons while they operate in their home institutions, and is widely accessible to trainees. Planned developments include enriched learning experiences with improved user friendliness, interactivity, and real-time feedback. PMID:26259999

  5. An Optimal Pull-Push Scheduling Algorithm Based on Network Coding for Mesh Peer-to-Peer Live Streaming

    NASA Astrophysics Data System (ADS)

    Cui, Laizhong; Jiang, Yong; Wu, Jianping; Xia, Shutao

    Most large-scale Peer-to-Peer (P2P) live streaming systems are constructed as a mesh structure, which can provide robustness in the dynamic P2P environment. The pull scheduling algorithm is widely used in this mesh structure, which degrades the performance of the entire system. Recently, network coding was introduced in mesh P2P streaming systems to improve the performance, which makes the push strategy feasible. One of the most famous scheduling algorithms based on network coding is R2, with a random push strategy. Although R2 has achieved some success, the push scheduling strategy still lacks a theoretical model and optimal solution. In this paper, we propose a novel optimal pull-push scheduling algorithm based on network coding, which consists of two stages: the initial pull stage and the push stage. The main contributions of this paper are: 1) we put forward a theoretical analysis model that considers the scarcity and timeliness of segments; 2) we formulate the push scheduling problem to be a global optimization problem and decompose it into local optimization problems on individual peers; 3) we introduce some rules to transform the local optimization problem into a classical min-cost optimization problem for solving it; 4) We combine the pull strategy with the push strategy and systematically realize our scheduling algorithm. Simulation results demonstrate that decode delay, decode ratio and redundant fraction of the P2P streaming system with our algorithm can be significantly improved, without losing throughput and increasing overhead.

  6. iTunes song-gifting is a low-cost, efficient recruitment tool to engage high-risk MSM in internet research.

    PubMed

    Holland, Christine M; Ritchie, Natalie D; Du Bois, Steve N

    2015-10-01

    This brief report describes methodology and results of a novel, efficient, and low-cost recruitment tool to engage high-risk MSM in online research. We developed an incentivization protocol using iTunes song-gifting to encourage participation of high-risk MSM in an Internet-based survey of HIV status, childhood sexual abuse, and adult behavior and functioning. Our recruitment methodology yielded 489 participants in 4.5 months at a total incentive cost of $1.43USD per participant. The sample comprised a critically high-risk group of MSM, including 71.0 % who reported recent condomless anal intercourse. We offer a "how-to" guide to aid future investigators in using iTunes song-gifting incentives. PMID:26174208

  7. Learner Outcomes and Satisfaction: A Comparison of Live Video-Streamed Instruction, Satellite Broadcast Instruction, and Face-to-Face Instruction

    ERIC Educational Resources Information Center

    Abdous, M'hammed; Yoshimura, Miki

    2010-01-01

    This study examined the final grade and satisfaction level differences among students taking specific courses using three different methods: face-to-face in class, via satellite broadcasting at remote sites, and via live video-streaming at home or at work. In each case, the same course was taught by the same instructor in all three delivery

  8. The impact of playout policy on the performance of P2P live streaming: or how not to kill your P2P advantage

    NASA Astrophysics Data System (ADS)

    Vassilakis, Constantinos; Laoutaris, Nikolaos; Stavrakakis, Ioannis

    2008-01-01

    In this paper we examine the impact of the adopted playout policy on the performance of P2P live streaming systems. We argue and demonstrate experimentally that (popular) playout policies which permit the divergence of the playout points of different nodes can deteriorate drastically the performance of P2P live streaming. Consequently, we argue in favor of keeping different playout points "near-in-time", even if this requires sacrificing (dropping) some late frames that could otherwise be rendered (assuming no strict bidirectional interactivity requirements are in place). Such nearly synchronized playout policies create "positive correlation" with respect to the available frames at different playout buffers. Therefore, they increase the number of upstream relay nodes from which a node can pull frames and thus boost the playout quality of both single-parent (tree) and multiple-parent (mesh) systems. On the contrary, diverging playout points reduce the number of upstream parents that can offer a gapless relay of the stream. This is clearly undesirable and should be avoided as it contradicts the fundamental philosophy of P2P systems which is to supplement an original service point with as many additional ones presented by the very own users of the service.

  9. StreamWorks: the live and on-demand audio/video server and its applications in medical information systems

    NASA Astrophysics Data System (ADS)

    Akrout, Nabil M.; Gordon, Howard; Palisson, Patrice M.; Prost, Remy; Goutte, Robert

    1996-05-01

    Facing a world undergoing fundamental and rapid change, healthcare organizations are seeking ways to increase innovation, quality, productivity, and patient value, keys to more effective care. Individual clinics acting alone can respond in only a limited way, so re- engineering the process key which services are delivered demands real-time collaborative technology that provides immediate information sharing, improving the management and coordination of information in cross-functional teams. StreamWorks is a development stage architecture that uses a distribution technique to deliver an advanced information management system for telemedicine. The challenge of StreamWorks in telemedicine is to enable equity of the quality of Health Care of Telecommunications and Information Technology also to patients in less favored regions, like India or China, where the quality of medical care varies greatly by region, but where there are some very current communications facilities.

  10. MATIN: A Random Network Coding Based Framework for High Quality Peer-to-Peer Live Video Streaming

    PubMed Central

    Barekatain, Behrang; Khezrimotlagh, Dariush; Aizaini Maarof, Mohd; Ghaeini, Hamid Reza; Salleh, Shaharuddin; Quintana, Alfonso Ariza; Akbari, Behzad; Cabrera, Alicia Trivio

    2013-01-01

    In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay. PMID:23940530

  11. MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

    PubMed

    Barekatain, Behrang; Khezrimotlagh, Dariush; Aizaini Maarof, Mohd; Ghaeini, Hamid Reza; Salleh, Shaharuddin; Quintana, Alfonso Ariza; Akbari, Behzad; Cabrera, Alicia Trivio

    2013-01-01

    In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay. PMID:23940530

  12. Presence of pharmaceuticals in benthic fauna living in a small stream affected by effluent from a municipal sewage treatment plant.

    PubMed

    Grabicova, Katerina; Grabic, Roman; Blaha, Martin; Kumar, Vimal; Cerveny, Daniel; Fedorova, Ganna; Randak, Tomas

    2015-04-01

    Aquatic organisms can be affected not only via polluted water but also via their food. In the present study, we examined bioaccumulation of seventy pharmaceuticals in two benthic organisms, Hydropsyche sp. and Erpobdella octoculata in a small stream affected by the effluent from a sewage treatment plant (STP) in Prachatice (South Bohemia region, Czech Republic). Furthermore, water samples from similar locations were analyzed for all seventy pharmaceuticals. In water samples from a control locality situated upstream of the STP, ten of the seventy pharmaceuticals were found with average total concentrations of 200ngL(-1). In water samples collected at STP-affected sites (downstream the STP's effluent), twenty-nine, twenty-seven and twenty-nine pharmaceuticals were determined at average total concentrations of 2000, 2100 and 1700ngL(-1), respectively. Six of the seventy pharmaceuticals (azithromycin, citalopram, clarithromycin, clotrimazole, sertraline, and verapamil) were found in Hydropsyche. Four pharmaceuticals (clotrimazole, diclofenac, sertraline, and valsartan) were detected in Erpobdella. Using evaluation criterion bioconcentration factor (BCF) is higher than 2000 we can assign azithromycin and sertraline as bioaccumulative pharmaceuticals. Even pharmaceuticals present at low levels in water were found in benthic organisms at relatively high concentrations (up to 85ngg(-1)w.w. for azithromycin). Consequently, the uptake of pharmaceuticals via the food web could be an important exposure pathway for the wild fish population. PMID:25283339

  13. CONNECTICUT STREAMS

    EPA Science Inventory

    This is a 1:24,000-scale datalayer of named streams in Connecticut. It includes two Shapefiles with line and polygon features. Both Shapefiles should be used together. The polygon shapefile fills in open water streams such as the Connecticut River as well as Long Island Sound. T...

  14. Stream Processors

    NASA Astrophysics Data System (ADS)

    Erez, Mattan; Dally, William J.

    Stream processors, like other multi core architectures partition their functional units and storage into multiple processing elements. In contrast to typical architectures, which contain symmetric general-purpose cores and a cache hierarchy, stream processors have a significantly leaner design. Stream processors are specifically designed for the stream execution model, in which applications have large amounts of explicit parallel computation, structured and predictable control, and memory accesses that can be performed at a coarse granularity. Applications in the streaming model are expressed in a gather-compute-scatter form, yielding programs with explicit control over transferring data to and from on-chip memory. Relying on these characteristics, which are common to many media processing and scientific computing applications, stream architectures redefine the boundary between software and hardware responsibilities with software bearing much of the complexity required to manage concurrency, locality, and latency tolerance. Thus, stream processors have minimal control consisting of fetching medium- and coarse-grained instructions and executing them directly on the many ALUs. Moreover, the on-chip storage hierarchy of stream processors is under explicit software control, as is all communication, eliminating the need for complex reactive hardware mechanisms.

  15. Biosorption beads for removal of dissolved metals from aqueous streams

    SciTech Connect

    Scott, C.D.

    1988-01-21

    This invention is comprised of a process for removing heavy metals from aqueous waste streams 5 by contacting such streams with certain biological adsorbents, either living, dead or in fragments, that may be immobilized in gel beads. 1 tab.

  16. Salamander occupancy in headwater stream networks

    USGS Publications Warehouse

    Grant, E.H.C.; Green, L.E.; Lowe, W.H.

    2009-01-01

    1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches. 2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders. 3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information-theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history. 4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region. 5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.

  17. Cellular Subcompartments through Cytoplasmic Streaming.

    PubMed

    Pieuchot, Laurent; Lai, Julian; Loh, Rachel Ann; Leong, Fong Yew; Chiam, Keng-Hwee; Stajich, Jason; Jedd, Gregory

    2015-08-24

    Cytoplasmic streaming occurs in diverse cell types, where it generally serves a transport function. Here, we examine streaming in multicellular fungal hyphae and identify an additional function wherein regimented streaming forms distinct cytoplasmic subcompartments. In the hypha, cytoplasm flows directionally from cell to cell through septal pores. Using live-cell imaging and computer simulations, we identify a flow pattern that produces vortices (eddies) on the upstream side of the septum. Nuclei can be immobilized in these microfluidic eddies, where they form multinucleate aggregates and accumulate foci of the HDA-2 histone deacetylase-associated factor, SPA-19. Pores experiencing flow degenerate in the absence of SPA-19, suggesting that eddy-trapped nuclei function to reinforce the septum. Together, our data show that eddies comprise a subcellular niche favoring nuclear differentiation and that subcompartments can be self-organized as a consequence of regimented cytoplasmic streaming. PMID:26305593

  18. Streams of Content, Limited Attention: The Flow of Information through Social Media

    ERIC Educational Resources Information Center

    Boyd, Danah

    2010-01-01

    The future of Web 2.0 is about content streams or streams of information. The metaphor implied by "streams" is powerful. The idea is that individuals are living inside the stream: adding to it, consuming it, redirecting it. The goal today is to be attentively aligned--"in flow"--with these information streams, to be aware of information as it

  19. ISS Live!

    NASA Technical Reports Server (NTRS)

    Price, Jennifer; Harris, Philip; Hochstetler, Bruce; Guerra, Mark; Mendez, Israel; Healy, Matthew; Khan, Ahmed

    2013-01-01

    International Space Station Live! (ISSLive!) is a Web application that uses a proprietary commercial technology called Lightstreamer to push data across the Internet using the standard http port (port 80). ISSLive! uses the push technology to display real-time telemetry and mission timeline data from the space station in any common Web browser or Internet- enabled mobile device. ISSLive! is designed to fill a unique niche in the education and outreach areas by providing access to real-time space station data without a physical presence in the mission control center. The technology conforms to Internet standards, supports the throughput needed for real-time space station data, and is flexible enough to work on a large number of Internet-enabled devices. ISSLive! consists of two custom components: (1) a series of data adapters that resides server-side in the mission control center at Johnson Space Center, and (2) a set of public html that renders the data pushed from the data adapters. A third component, the Lightstreamer server, is commercially available from a third party and acts as an intermediary between custom components (1) and (2). Lightstreamer also provides proprietary software libraries that are required to use the custom components. At the time of this reporting, this is the first usage of Web-based, push streaming technology in the aerospace industry.

  20. Inventory of miscellaneous streams

    SciTech Connect

    Haggard, R.D.

    1998-08-14

    Miscellaneous streams discharging to the soil column on the Hanford Site are subject to requirements of several milestones identified in Consent Order No. DE 9INM-177 (Ecology and DOE 1991). The Plan and Schedule for Disposition and Regulatory Compliance for Miscellaneous Stream (DOE/RL-93-94) provides a plan and schedule for the disposition of miscellaneous streams to satisfy one of the Section 6.0 requirements of the Consent Order. One of the commitments (Activity 6-2.2) established in the plan and schedule is to annually update, the miscellaneous streams inventory. This document constitutes the 1998 revision of the miscellaneous streams inventory. Miscellaneous stream discharges were grouped into four permitting categories (Table 1). The first miscellaneous streams Permit (ST 4508) was issued May 30, 1997, to cover wastewater discharges from hydrotesting, maintenance, and construction activities. The second miscellaneous streams Permit (ST4509) covers discharges from cooling water and condensate discharges. The third permit application for category three waste streams was eliminated by recategorizing waste streams into an existing miscellaneous streams permit or eliminating stream discharges. Elimination of the third categorical permit application was approved by Ecology in January 1997 (Ecology 1997). The fourth permit application, to cover storm water, is due to Ecology in September 1998. Table 1 provides a history of the miscellaneous streams permitting activities.

  1. Prioritized Contact Transport Stream

    NASA Technical Reports Server (NTRS)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  2. Regex-Stream

    Energy Science and Technology Software Center (ESTSC)

    2012-09-01

    Log files are typically semi-or un-structured. To be useable, they need to be parsed into a standard, structured format. Regex-Stream facilitates parsing text files into structured data (JSON) in streams of data.

  3. Saving Our Streams.

    ERIC Educational Resources Information Center

    Firehock, Karen

    1993-01-01

    Presents an Izaak Walton League of America's Save Our Streams (SOS) program that teaches citizens how to protect streams. This organization provides activities for families, school groups, scout troops, 4-H clubs and other youth organizations. (MCO)

  4. Experimental Stream Segment

    USGS Multimedia Gallery

    One of six experimental stream segments used to study the dispersal of free embryo sturgeon at the Columbia Environmental Research Center.  The stream segment is 5 meters long and 0.5 meters wide, and is filled with cobble-sized rock to a depth of 12 centimeters.  Streams are covered durin...

  5. Delivering Instruction via Streaming Media: A Higher Education Perspective.

    ERIC Educational Resources Information Center

    Mortensen, Mark; Schlieve, Paul; Young, Jon

    2000-01-01

    Describes streaming media, an audio/video presentation that is delivered across a network so that it is viewed while being downloaded onto the user's computer, including a continuous stream of video that can be pre-recorded or live. Discusses its use for nontraditional students in higher education and reports on implementation experiences. (LRW)

  6. Assisted Living

    MedlinePLUS

    ... but they don't need full-time nursing care. Some assisted living facilities are part of retirement ... change. Assisted living costs less than nursing home care. It is still fairly expensive. Older people or ...

  7. PERCENT FOREST ADJACENT TO STREAMS

    EPA Science Inventory

    The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept pollutants before they reach the stream. Forest cover along streams (RIPFOR) is the percent of total stream length adjacent...

  8. The Puzzling Ophiuchus Stream

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Dwarf galaxies or globular clusters orbiting the Milky Way can be pulled apart by tidal forces, leaving behind a trail of stars known as a stellar stream. One such trail, the Ophiuchus stream, has posed a serious dynamical puzzle since its discovery. But a recent study has identified four stars that might help resolve this streams mystery.Conflicting TimescalesThe stellar stream Ophiuchus was discovered around our galaxy in 2014. Based on its length, which appears to be 1.6 kpc, we can calculate the time that has passed since its progenitor was disrupted and the stream was created: ~250 Myr. But the stars within it are ~12 Gyr old, and the stream orbits the galaxy with a period of ~350 Myr.Given these numbers, we can assume that Ophiuchuss progenitor completed many orbits of the Milky Way in its lifetime. So why would it only have been disrupted 250 million years ago?Fanning StreamLed by Branimir Sesar (Max Planck Institute for Astronomy), a team of scientists has proposed an idea that might help solve this puzzle. If the Ophiuchus stellar stream is on a chaotic orbit common in triaxial potentials, which the Milky Ways may be then the stream ends can fan out, with stars spreading in position and velocity.The fanned part of the stream, however, would be difficult to detect because of its low surface brightness. As a result, the Ophiuchus stellar stream could actually be longer than originally measured, implying that it was disrupted longer ago than was believed.Search for Fan StarsTo test this idea, Sesar and collaborators performed a search around the ends of the stream, looking for stars thatare of the right type to match the stream,are at the predicted distance of the stream,are located near the stream ends, andhave velocities that match the stream and dont match the background halo stars.Histogram of the heliocentric velocities of the 43 target stars. Six stars have velocities matching the stream velocity. Two of these are located in the main stream; the other four may be part of a fan at the end of the stream. [Sesar et al. 2016]Of the 43 targets for which the authors obtained spectra, four stars met these criteria and are located beyond the main extent of the stream, possibly comprising a fan at the streams end. Including these stars as part of the Ophiuchus stream, its length becomes 3 kpc, implying that its time of disruption was closer to 400 million years ago. This relieves the timescale tension but does not resolve it.That said, the mere evidence of a fan in the Ophiuchus stream suggests that its progenitor may have been on a chaotic orbit. If this is the case, its entirely possible that the progenitor could have survived for ~11 Gyr, only to have been disrupted within the last 0.5 Gyr. Detailed modeling and further identification of potential fan stars in the Ophiuchus stream will help to test this idea and resolve the puzzle of this stream.CitationBranimir Sesar et al 2016 ApJ 816 L4. doi:10.3847/2041-8205/816/1/L4

  9. Production stream analyzer

    SciTech Connect

    Bussian, A.E.; Williams, T.M.; Carmichael, P.D.; Paap, H.J.

    1988-02-07

    A production stream analyzer is described for use with a flowing crude oil production stream which also includes water and gas in a conduit comprises: a sensor sensing the temperature of the flowing production stream and providing a temperature signal representative thereof, monitoring means for monitoring the capacitance of the production stream and providing a corresponding capacitance signal, a densitometer measuring the density of the production stream and providing a density signal corresponding thereto, and output means connected to the sensor, to the monitoring means and to the densitometer for providing output signals corresponding to the quantity of at least one constituent of the production stream in accordance with the temperature, the capacitance and the density signals.

  10. Gas stream purifier

    NASA Technical Reports Server (NTRS)

    Adam, Steven J.

    1994-01-01

    A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

  11. Inventory of miscellaneous streams

    SciTech Connect

    Lueck, K.J.

    1995-09-01

    On December 23, 1991, the US Department of Energy, Richland Operations Office (RL) and the Washington State Department of Ecology (Ecology) agreed to adhere to the provisions of the Department of Ecology Consent Order. The Consent Order lists the regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code. The RL provided the US Congress a Plan and Schedule to discontinue disposal of contaminated liquid effluent into the soil column on the Hanford Site. The plan and schedule document contained a strategy for the implementation of alternative treatment and disposal systems. This strategy included prioritizing the streams into two phases. The Phase 1 streams were considered to be higher priority than the Phase 2 streams. The actions recommended for the Phase 1 and 2 streams in the two reports were incorporated in the Hanford Federal Facility Agreement and Consent Order. Miscellaneous Streams are those liquid effluents streams identified within the Consent Order that are discharged to the ground but are not categorized as Phase 1 or Phase 2 Streams. This document consists of an inventory of the liquid effluent streams being discharged into the Hanford soil column.

  12. Dynamics of meteor streams

    NASA Technical Reports Server (NTRS)

    Babadjanov, P. B.; Obrubov, Yu. U.

    1987-01-01

    The overwhelming majority of meteor streams are generally assumed to be formed due to the decay of comets. The most effective process of the release of solid particles from a cometary nucleus is their ejection by sublimating gases when the comet approaches the Sun. The results of investigation of the Geminids and Quadrantids meteor stream evolution show that under the influence of planetary perturbations, the stream may originally be flat but then thicken depending on the variation range of orbital inclinations. Eventually, due to planetary perturbations, a meteor stream may take such a shape as to cause the start of several active showers at different solar longitudes.

  13. User aware video streaming

    NASA Astrophysics Data System (ADS)

    Kerofsky, Louis; Jagannath, Abhijith; Reznik, Yuriy

    2015-03-01

    We describe the design of a video streaming system using adaptation to viewing conditions to reduce the bitrate needed for delivery of video content. A visual model is used to determine sufficient resolution needed under various viewing conditions. Sensors on a mobile device estimate properties of the viewing conditions, particularly the distance to the viewer. We leverage the framework of existing adaptive bitrate streaming systems such as HLS, Smooth Streaming or MPEG-DASH. The client rate selection logic is modified to include a sufficient resolution computed using the visual model and the estimated viewing conditions. Our experiments demonstrate significant bitrate savings compare to conventional streaming methods which do not exploit viewing conditions.

  14. WADEABLE STREAMS ASSESSMENT

    EPA Science Inventory

    This Wadeable Streams Assessment (WSA) provides the first statistically defensible summary of the condition of the nation’s streams and small rivers, which are so integrally tied to our history. This report brings the results of this ground-breaking study to the American public....

  15. MARYLAND BIOLOGICAL STREAM SURVEY

    EPA Science Inventory

    The Maryland Biological Stream Survey (MBSS) is a multi-year probability-based sampling program designed to assess the status of biological resources in non-tidal streams of Maryland. The MBSS is quantifying the extent to which acidic deposition and other human activities have af...

  16. WADEABLE STREAMS ASSESSMENT

    EPA Science Inventory

    This Wadeable Streams Assessment (WSA) provides the first statistically defensible summary of the condition of the nations streams and small rivers, which are so integrally tied to our history. This report brings the results of this ground-breaking study to the American public....

  17. FUTURE ROADS NEAR STREAMS

    EPA Science Inventory

    Roads are a source of auto related pollutants (e.g. gasoline, oil and other engine fluids). When roads are near streams, rain can wash these pollutants directly into the stream, harming both water and habitat quality. This metric measured the length of roads within 30 meters of a...

  18. ROADS NEAR STREAMS

    EPA Science Inventory

    Roads are a source of auto related pollutants (e.g. gasoline, oil and other engine fluids). When roads are near streams, rain can wash these pollutants directly into the stream, harming both water and habitat quality. This metric measured the length of roads within 30 meters of a...

  19. Citrus waste stream utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Waste streams, generated during fruit processing, consist of solid fruit residues in addition to liquid waste streams from washing operations which must be handled in an environmentally acceptable manner. Unsound fruit from packing houses are usually sent off to be processed for juice and the solid ...

  20. Ramification of stream networks

    PubMed Central

    Devauchelle, Olivier; Petroff, Alexander P.; Seybold, Hansjörg F.; Rothman, Daniel H.

    2012-01-01

    The geometric complexity of stream networks has been a source of fascination for centuries. However, a comprehensive understanding of ramification—the mechanism of branching by which such networks grow—remains elusive. Here we show that streams incised by groundwater seepage branch at a characteristic angle of 2π/5 = 72°. Our theory represents streams as a collection of paths growing and bifurcating in a diffusing field. Our observations of nearly 5,000 bifurcated streams growing in a 100 km2 groundwater field on the Florida Panhandle yield a mean bifurcation angle of 71.9° ± 0.8°. This good accord between theory and observation suggests that the network geometry is determined by the external flow field but not, as classical theories imply, by the flow within the streams themselves. PMID:23223562

  1. PERCENT AGRICULTURE ADJACENT TO STREAMS

    EPA Science Inventory

    The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept pollutants before they reach the stream. High percentages of agriculture along streams increase the likelihood of elevated ...

  2. Asteroid/meteorite streams

    NASA Technical Reports Server (NTRS)

    Drummond, J.

    1991-01-01

    The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential near-Earth resource.

  3. Bachelor Living

    ERIC Educational Resources Information Center

    Germer, Sondra

    1974-01-01

    Male high school students in a Bachelor Living Class observed methods of child care including bottle feeding, spoon feeding, changing diapers, and method of holding. The purpose was for the students to grasp a better understanding of child development. (EK)

  4. Living Laboratories

    ERIC Educational Resources Information Center

    Mules, B. R.

    1976-01-01

    Presented is a review of various methods of keeping live animals, including scorpions, spiders, crabs, crayfish, shrimp, ants, fish, mice, and birds, as well as plants as a school science project/display. (SL)

  5. Assisted Living

    MedlinePLUS

    ... programs Personal laundry services Social and recreational activities Personal care in assisted living typically includes: Staff available ... today pay for long-term care from their personal financial resources, 41 states offer "home and community- ...

  6. Assisted Living

    MedlinePLUS

    ... Recreational activities Security Transportation How to Choose a Facility A good match between a facility and a resident's needs depends as much on the philosophy and services of the assisted living facility as it does on the quality of care. ...

  7. Solar wind stream interfaces

    NASA Technical Reports Server (NTRS)

    Gosling, J. T.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.

    1978-01-01

    Results are presented for a superposed epoch analysis of discontinuous solar wind interfaces. The average time-space profiles of stream interfaces are discussed with reference to fluid properties (flow speed, pressure ridge, density, electron and proton temperatures) and kinetic properties (electron core and halo, flow speed fluctuations, electron heat flux, alpha particles). Other aspects of stream interfaces are described, such as the persistence of individual interfaces, shock associations, the sector boundaries of the interplanetary magnetic field, and sudden impulses in the geomagnetic field. Interface position is considered in terms of the observed temperature jump. A conceptual model of high-speed stream evolution is proposed.

  8. Twitter Stream Archiver

    Energy Science and Technology Software Center (ESTSC)

    2014-07-01

    The Twitter Archiver system allows a user to enter their Twitter developer account credentials (obtained separately from the Twitter developer website) and read from the freely available Twitter sample stream. The Twitter sample stream provides a random sample of the overall volume of tweets that are contributed by users to the system. The Twitter Archiver system consumes the stream and serializes the information to text files at some predefined interval. A separate utility reads themore » text files and creates a searchable index using the open source Apache Lucene text indexing system.« less

  9. Twitter Stream Archiver

    SciTech Connect

    2014-07-01

    The Twitter Archiver system allows a user to enter their Twitter developer account credentials (obtained separately from the Twitter developer website) and read from the freely available Twitter sample stream. The Twitter sample stream provides a random sample of the overall volume of tweets that are contributed by users to the system. The Twitter Archiver system consumes the stream and serializes the information to text files at some predefined interval. A separate utility reads the text files and creates a searchable index using the open source Apache Lucene text indexing system.

  10. Streaming potential measurements of biosurfaces

    NASA Technical Reports Server (NTRS)

    Van Wagenen, R. A.; Andrade, J. D.; Hibbs, J. B., Jr.

    1976-01-01

    A technique based on the measurement of streaming potentials has been developed to evaluate the electrokinetic region of the cell periphery. This approach is feasible for cell lines propagated in in-vitro cell cultures in monolayer form. The advantage of this system is that cells may be evaluated in the living state atttached to a substrate; it is not necessary to subject the cells to enzymatic, chemical, or mechanical trauma required to obtain monodisperse suspensions which are then normally evaluated by microelectrophoresis. In this manner, it should be possible to study the influence of substrate and environmental factors on the charge density and potential at the cell periphery. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of borosilicate capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming-potential measurements is discussed. The electrokinetic potential of BALB/c 3T12 fibroblasts has been quantified as a function of pH, ionic strength, glutaraldehyde fixation, and Giemsa staining.

  11. River and Stream Pollution

    MedlinePLUS

    ... washing into lakes and streams comes from exposed earth. This exposed earth includes plowed fields, construction sites, and areas that ... using new methods to reduce the amount of earth they disturb. Bacteria Bacteria are also a big ...

  12. Urban Stream Ecology

    EPA Science Inventory

    Urban watersheds characteristically have high impervious surface cover, resulting in high surface runoff and low infiltration following storms. In response, urban streams experience “flashy” stormflows, reduced baseflows, bank erosion, channel widening, and sedimentation. Urban ...

  13. Streaming tearing mode

    NASA Technical Reports Server (NTRS)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  14. Urban Stream Ecology

    EPA Science Inventory

    Urban watersheds characteristically have high impervious surface cover, resulting in high surface runoff and low infiltration following storms. In response, urban streams experience flashy stormflows, reduced baseflows, bank erosion, channel widening, and sedimentation. Urban ...

  15. Replay-Stream

    Energy Science and Technology Software Center (ESTSC)

    2012-12-01

    For testing and demonstration purposes, it is often necessary to replay saved network and log data. This library facilitates replaying these saved data streams. This module will take in a stream of JSON strings, read their specified timestamp field, and output according to the given criteria. This can include restricting output to a certain time range, and/or outputting the items with some delay based on their timestamp.

  16. Chaos and stellar streams

    NASA Astrophysics Data System (ADS)

    Price-Whelan, Adrian M.; Johnston, Kathryn V.; Valluri, Monica; Pearson, Sarah; Kupper, Andreas Hans Wilhelm; Hogg, David W.

    2016-01-01

    Cosmological simulations predict that dark matter halos around galaxies should be triaxial in shape with universal density profiles. A significant number of orbits in such systems are chaotic, though it is commonly assumed that chaos is not dynamically relevant for galaxy halos because the timescales over which chaos is computed to be important are generally long relative to the dynamical time. In recent work, we showed that even when chaos is not important for restructuring the global structure of a galaxy, chaos can greatly enhance the density evolution and alter the morphologies of stellar streams over just a few orbital times by causing streams to 'fan out.' This occurs because the orbits of the stars in stellar streams have small distributions of fundamental frequencies and are therefore sensitive to mild chaos that modulates the frequencies on small-scales over much faster timescales. This suggests that the morphology of tidal streams alone can be used to estimate the significance of chaos along the orbits of the progenitor systems, thereby placing constraints on the global properties of the gravitational potential. I will explain our theoretical understanding of this phenomenon and discuss implications for a recently discovered stellar stream (the Ophiuchus stream) that may be on a chaotic orbit in the inner Milky Way due to the influence of the time-dependent, triaxial potential of the Galactic bar.

  17. Learn & Live.

    ERIC Educational Resources Information Center

    Burness, Patty, Ed.; Snider, William, Ed.

    Along with a companion documentary video, "Learn & Live," this resource manual focuses on innovative schools around the country that are integrating technology and involving parents, business, and the community. Ten chapters are divided into four sections. In Section 1, "Students," two chapters look at learning and assessment. The two chapters in

  18. Living History

    ERIC Educational Resources Information Center

    Walsh, Mark

    2005-01-01

    John Tinker and Mary Beth Tinker are back in a classroom in their hometown, once again wearing black armbands and drawing attention to a war. Now in their 50s, the siblings are living symbols of constitutional rights for secondary school students. In 1965, they and a handful of others were suspended for wearing black armbands to their public

  19. Independent Living.

    ERIC Educational Resources Information Center

    Nathanson, Jeanne H., Ed.

    1994-01-01

    This issue of "OSERS" addresses the subject of independent living of individuals with disabilities. The issue includes a message from Judith E. Heumann, the Assistant Secretary of the Office of Special Education and Rehabilitative Services (OSERS), and 10 papers. Papers have the following titles and authors: "Changes in the Rehabilitation Act of…

  20. Countryside Live!

    ERIC Educational Resources Information Center

    Best, Andrew; Richardson, Gary

    2006-01-01

    The "Countryside Live!" events, organised by the Countryside Foundation for Education (CFE), provide a unique opportunity for urban children to explore a whole new area of possibilities and learning, through becoming aware at first-hand of what goes on in the countryside. The event at Staunton Country Park, Havant, Hampshire, which took place on

  1. Retiring Lives

    ERIC Educational Resources Information Center

    Carnell, Eileen, Ed.; Lodge, Caroline, Ed.

    2009-01-01

    "Retiring Lives" presents fourteen personal real life stories from people at various stages of retiring. Each author recounts their own story about retiring, bringing together many aspects of the experiences: the social, psychological and practical. These inspirational and illustrated stories will encourage the reader to hold up these experiences…

  2. Retiring Lives

    ERIC Educational Resources Information Center

    Carnell, Eileen, Ed.; Lodge, Caroline, Ed.

    2009-01-01

    "Retiring Lives" presents fourteen personal real life stories from people at various stages of retiring. Each author recounts their own story about retiring, bringing together many aspects of the experiences: the social, psychological and practical. These inspirational and illustrated stories will encourage the reader to hold up these experiences

  3. Healthy Living

    MedlinePLUS

    Many factors affect your health. Some you cannot control, such as your genetic makeup or your age. But you can make changes to your lifestyle. By taking steps toward healthy living, you can help reduce your risk of heart disease, cancer, stroke and other serious diseases: Get the screening tests you ...

  4. Gaia Live in School

    NASA Astrophysics Data System (ADS)

    Walton, N. A.; Barnes, R.; Soubiran, C.; Vogt, S.

    2014-07-01

    Gaia is the European Space Agency's (ESA) next major astronomy telescope mission that was launched December 19, 2013. Gaia will measure accurate distances to about one billion stars across our Milky Way, allowing us to better understand how our galaxy formed and evolved. Gaia will have a profound impact on our understand ing of the Universe and the nature of dark matter, and provide a deeper understanding of how planets form around stars in our local neighbourhood. Gaia scientists and science education advisors are organising a Gaia post-launch event to link approximately forty schools across Europe. The event will include a live stream connection to ESA Gaia Mission Control and local Gaia research students to act as explainers and give practical demonstrations in each school. This paper describes the challenges in conducting this Europe-wide event.

  5. Inventory of miscellaneous streams

    SciTech Connect

    Atencio, B.P.

    1996-09-01

    On December 23, 1991, the U.S. Dep of Energy, Richland Operations Office (DOE-RL) and the Washington State Department of Ecology (Ecology) agreed to adhere to the provisions of the Department of Ecology Consent Order No. DE 9INM-177 (Consent Order) (Ecology and U.S. DOE 1991). The Consent Order lists the regulatory milestones for liquid effluent at the Hanford Site to comply with the permitting requirements of Washington Administrative Code (WAC) 173-216 (State Waste Discharge Permit Program) or WAC 173-218 (Washington Underground Injection Control Progam) where applicable. DOE-RL provided the U.S Congress a plan and schedule to discontinue disposal of contaminated liquid effluent into the soil column on the Hanford Site (DOE 1987). The plan and schedule document contained a strategy for the implementation of alternative treatment and disposal systems. This strategy included prioritizing the into two phases. The Phase I streams were considered to be higher priority than the Phase II streams. The actions recommended for the Phase I and II streams were incorporated in the Hanford Federal Facility A and Consent Order (Tri Party Agreement ) (Ecology, et al. 1994). Miscellaneous Streams are those liquid effluent identified within the Consent Order that are discharged to the ground but are not categorized as Phase I or Phase II Streams. Miscellaneous discharging to the soil column on the Hanford Site are subject to requirements of several milestones identified in the Consent Order. The Plan and Schedule for Disposition and Regulatory Compliance for Miscellaneous Streams (DOE/RL,93-94) provides a plan and schedule for the disposition of Miscellaneous Streams to satisfy one of the Consent Order requirements. One of the commitments (Activity 6-2.2) established in the plan and schedule is to annually update the Miscellaneous Stream Inventory. The annual update will continue until September of 1998, at which time four categorical permit applications are scheduled to have been submitted to Ecology. This document constitutes the 1996 revision of the Inventory of Miscellaneous Streanu. This inventory has been used to prepare the State Waste Discharge Permit Application for Cooling Water and Condensate Discharges (DOE/RL,96-41) and the Miscellaneous Stream Best Management Practice Report (DOE/RL-96-40). This inventory will also be used to prepare the third and fourth categorical permit applications as defined in the plan and schedule.

  6. Consider an Ice Stream.

    NASA Astrophysics Data System (ADS)

    Bindschadler, R.

    2002-12-01

    Forty years ago, John Nye was one of the leaders who introduced the rigors of classical physics to glaciology. His elegant treatments frequently took advantage of the then recent discovery that ice could be approximated as a plastic material. With this viewpoint, Nye was able to explain the shape of ice sheets and glaciers, to predict the expected pattern of stress and velocity within a glacier, and to derive the advance and retreat of a glacier from the record of accumulation and ablation. These advances have given generations of glaciologists tools to interpret the excellent observational record of glacier behavior and variation. In the 1980s, glaciologist, weaned on these works of Nye and of other similarly adept colleagues, carried their lessons to West Antarctica to study ice streams, the vast conveyor belts of ice that discharged nearly as much Antarctic ice as the much larger East Antarctic ice sheet. Ice streams were a glaciological conundrum. Despite the gently sloping surface, these broad features roared along, moving fastest when the gravitational impetus was least. After two decades of research, ice streams still have not given up all their secrets, yet much is now known. Internal deformation is negligible. Basal friction is frequently nil leaving the shattered margins as the primary means to avoid rapid wastage of the ice sheet. Within the margins, the resistive force results from a delicate balance of heat and evolving ice fabrics. Nevertheless, the bed beneath an ice stream cannot be ignored. It is ultimately the state of the underlying marine sediment that determines whether the ice stream can slide at all. There too, the heat balance is critical with an influx of water required to keep the bed wet enough to let the streams glide along. Ice stream research has been the portal through which glaciologists have seen and identified the complexities of West Antarctic ice sheet dynamics. Remarkably, nearly all time scales seem important. Ice stream positions in past millennia conform to radically different flow patterns while on the scale of hours an ice stream's motion is halted completely, then released to move at surge-like speeds, in tempo with the tides. Explaining these complexities constantly reminds us that the rigorous physics applied to ice so effectively by Nye still work.

  7. Crude oil production stream analyzer

    SciTech Connect

    Meador, R.A.; Paap, H.J.

    1984-07-10

    A crude oil production stream analyzer includes a device which measures the dielectric constant of the crude oil production stream and provides a signal corresponding thereto. A densitometer provides a density signal representative of the density of the crude oil production stream. At least one constituent of the crude oil production stream is determined in accordance with the dielectric constant signal and the density signal and the temperature of the crude oil production stream which is sensed by a temperature sensor.

  8. FACTORS CONTROLLING HYDROLOGIC PERMANENCE OF HEADWATER STREAMS

    EPA Science Inventory

    Headwater streams compose the majority of stream miles within most drainages. Interest in monitoring headwater streams is increasing because headwater streams are vital linkages between upland land use and downstream water bodies. However, traditional stream assessment tools ar...

  9. The Sagittarius Dwarf Tidal Stream(s)

    NASA Astrophysics Data System (ADS)

    Law, David R.; Majewski, Steven R.

    The Milky Way's prominent and widely studied Sagittarius (Sgr) dSph tidal stream has proven a valuable tool for exploring a number of problems in galactic astronomy. In this review of the Sgr system, we present a descriptive portrait of the most salient and unambiguous observational properties (e.g., location, radial velocity, proper motion, and chemical composition) of the Sgr core and tidal streams as they are presently known. We discuss how the history of these observations has shaped the development of numerical models of the system over time, and some of the major conclusions that have been drawn from such modeling efforts with regard to the size and shape of the Milky Way's gravitational potential and the patterns of enrichment throughout its stellar halo. Finally, we summarize some of the known failings of the present models, which we lay out as a challenge for future progress on understanding this remarkable and fortuitous example of hierarchical galaxy growth via merging in action.

  10. Introduction to Tidal Streams

    NASA Astrophysics Data System (ADS)

    Newberg, Heidi Jo

    Dwarf galaxies that come too close to larger galaxies suffer tidal disruption; the differential gravitational force between one side of the galaxy and the other serves to rip the stars from the dwarf galaxy so that they instead orbit the larger galaxy. This process produces "tidal streams" of stars, which can be found in the stellar halo of the Milky Way, as well as in halos of other galaxies. This chapter provides a general introduction to tidal streams, including the mechanism through which the streams are created, the history of how they were discovered, and the observational techniques by which they can be detected. In addition, their use in unraveling galaxy formation histories and the distribution of dark matter in galaxies is discussed, as is the interaction between these dwarf galaxy satellites and the disk of the larger galaxy.

  11. Meandering stream reservoirs

    SciTech Connect

    Richardson, J.G.; Sangree, J.B.; Sneider, R.M.

    1987-12-01

    Braided stream deposits, described in a previous article in this series, and meandering stream deposits commonly are excellent reservoirs. Meandering high-sinuousity channels are found on flat alluvial plains with slopes less than 1 1/2/sup 0/ (0.026 rad). These rivers have wide ranges of discharges from low-water flow to flood stage. Two main processes are responsible for development of sand bodies. These are point-bar deposits left by channel migration, and oxbow-lake deposits left in loops of the river course abandoned when the stream cuts a new course during flooding. Extremely high floods spill over the banks and deposit sheets of very fine sand, silt, and clay onto the flood plain.

  12. The endoplasmic reticulum exerts control over organelle streaming during cell expansion.

    PubMed

    Stefano, Giovanni; Renna, Luciana; Brandizzi, Federica

    2014-03-01

    Cytoplasmic streaming is crucial for cell homeostasis and expansion but the precise driving forces are largely unknown. In plants, partial loss of cytoplasmic streaming due to chemical and genetic ablation of myosins supports the existence of yet-unknown motors for organelle movement. Here we tested a role of the endoplasmic reticulum (ER) as propelling force for cytoplasmic streaming during cell expansion. Through quantitative live-cell analyses in wild-type Arabidopsis thaliana cells and mutants with compromised ER structure and streaming, we demonstrate that cytoplasmic streaming undergoes profound changes during cell expansion and that it depends on motor forces co-exerted by the ER and the cytoskeleton. PMID:24424025

  13. STREAM WATER QUALITY MODEL

    EPA Science Inventory

    QUAL2K (or Q2K) is a river and stream water quality model that is intended to represent a modernized version of the QUAL2E (or Q2E) model (Brown and Barnwell 1987). Q2K is similar to Q2E in the following respects:

    • One dimensional. The channel is well-mixed vertically a...

    • STREAMS_P

      EPA Science Inventory

      Streams (polygon features) coverage showing some double line rivers and islands on the Colorado River Indian Reservation in Arizona. This coverage was digitized off of USGS 7.5 minute quad maps by the Phoenix office of the Bureau of Indian Affairs.

    • Lake and Stream Acidity

      EPA Science Inventory

      This indicator presents trends in the percentage of lakes and streams in selected regions in the Northeast and mid-Atlantic states that have been considered chronically acidic between 1987 and 2007. This information describes how the extent of acidification, a serious danger t...

    • Two Phase Streaming Potentials

      SciTech Connect

      Marsden, S.S.; Wheatall, M.W.

      1987-01-20

      The streaming potentials generated by the flow of both liquid and gas through either a Pyrex capillary tube or else an unconsolidated Pyrex porous medium were investigated. This mixture of distilled water plus nitrogen gas simulated wet stream but allowed experiments to be run at room temperature. Single-phase flow of distilled water alone resulted in a constant voltage-to-pressure drop ratio, E/∆p, of +0.15 v/psi for the capillary tube and -0.52 v/psi for the porous medium. For both single- and two-phase flow through the capillary tube, the upstream potential was always positive relative to the downstream electrode while the opposite was true for the porous medium. The maximum two-phase potentials generated in the porous medium were about four times as great as those generated in the capillary tube for similar gas fractions, Γ. For the capillary tube experiments the potentials generated when Γ < ≈ 0.5 were equal to or slightly less than those for single-phase flow, while for the porous medium the potentials were always greater than those for single-phase flow. When Γ > ≈ 0.5 for both kinds of flow systems Γ had a profound effect on streaming potential and reached a pronounced maximum when 0.94 < Γ < 0.99. The implications of these streaming potentials for geothermal exploration and delineation of geothermal reservoirs is also discussed in the paper. 7 figs., 10 refs.

    • BALTIMORE STREAM RESTORATION PROJECT

      EPA Science Inventory

      26 Feb 2003



      Approach - We will employ a 4-tiered research approach to investigate restoration effects on hydrology and stream water quality: 1) monitoring ground water and surface water, 2) quantifying denitrification activity, 3) measuring carbon supply and rete...

    • Practical Meteor Stream Forecasting

      NASA Technical Reports Server (NTRS)

      Cooke, William J.; Suggs, Robert M.

      2003-01-01

      Inspired by the recent Leonid meteor storms, researchers have made great strides in our ability to predict enhanced meteor activity. However, the necessary calibration of the meteor stream models with Earth-based ZHRs (Zenith Hourly Rates) has placed emphasis on the terran observer and meteor activity predictions are published in such a manner to reflect this emphasis. As a consequence, many predictions are often unusable by the satellite community, which has the most at stake and the greatest interest in meteor forecasting. This paper suggests that stream modelers need to pay more attention to the needs of this community and publish not just durations and times of maxima for Earth, but everything needed to characterize the meteor stream in and out of the plane of the ecliptic, which, at a minimum, consists of the location of maximum stream density (ZHR) and the functional form of the density decay with distance from this point. It is also suggested that some of the terminology associated with meteor showers may need to be more strictly defined in order to eliminate the perception of crying wolf by meteor scientists. An outburst is especially problematic, as it usually denotes an enhancement by a factor of 2 or more to researchers, but conveys the notion of a sky filled with meteors to satellite operators and the public. Experience has also taught that predicted ZHRs often lead to public disappointment, as these values vastly overestimate what is seen.

    • Experimental Stream Section

      USGS Multimedia Gallery

      Researchers at the Columbia Environmental Research Center will use experimental streams with sand, gravel or cobble bottoms to help to determine the influence of the different substrates on hatch and initiation of dispersal of pallid sturgeon free-embryos....

    • Amyloplast movement in living statocytes

      NASA Technical Reports Server (NTRS)

      Leopold, A. C.; Sack, F.

      1984-01-01

      Much evidence implicates amyloplast movement in plant graviperception. How this signal is transduced into a differential growth response is not known. Studies using fixed tissue are useful for deriving mean sedimentation rates, but cannot yield data on: the movement of individual amyloplasts, the role of cytoplasmic streaming, and the initial dynamic events occurring during the presentation time. These limitations were overcome by examining living tissue sections with a horizontally mounted microscope connected to a video camera and recorder. The kinetics of the early response to reorientation are consistent with the hypothesis that amyloplasts act by contact with a sensitive surface near the lower wall and indicate that cytoplasmic streaming provides an important vector in amyloplast redistribution in response to gravity.

  1. Does the restoration of an inner-city stream in Seoul affect local thermal environment?

    NASA Astrophysics Data System (ADS)

    Kim, Y.-H.; Ryoo, S.-B.; Baik, J.-J.; Park, I.-S.; Koo, H.-J.; Nam, J.-C.

    2008-05-01

    Changes in local thermal environment associated with the restoration of an inner-city stream in Seoul, Korea, are investigated using observational data. The stream, called the Cheonggye stream, which had been hidden and covered with cement/asphalt for 46 years, runs 5.8 km eastward through a central region of Seoul. Intensive observations were made in the stream area for a number of summertime periods before, during, and after the stream restoration to detect the effects of the stream on local environment and to quantify them. It is estimated that after the stream restoration the near-surface temperature averaged over the stream area dropped by 0.4 C, with the largest local temperature drop being 0.9 C. However, it cannot be stated that this 0.4 C temperature drop is due entirely to the stream effect only, because synoptic-scale and local-scale weather conditions during the two periods were inevitably not identical. The stream effect on air temperature is also evident in the temperature distribution along a street traversing the stream. In the daytime after the stream restoration, the sensible heat flux was greatly reduced and the ratio of sensible heat flux to net radiative flux dramatically decreased. These first-time results of the restored-stream effects on urban thermal environment could contribute to the scientific basis of urban planning which aims to make a large city comfortable to live in and nature- and environment-friendly.

  2. ASSESSING HEADWATER STREAMS: LINKING LANDSCAPES TO STREAM NETWORKS

    EPA Science Inventory

    Headwater streams represent a significant land-water boundary and drain 70-80% of the landscape. Headwater streams are vital components to drainage systems and are directly linked to our downstream rivers and lakes. However, alteration and loss of headwater streams have occurre...

  3. Benthic Macroinvertebrates in Wadeable Streams

    EPA Science Inventory

    This indicator describes the presence and distribution of benthic macroinvertebrates in wadeable streams nationwide as surveyed from 2000 to 2004. Benthic macroinvertebrates are particularly sensitive to disturbances in stream chemistry and physical habitat, making their prese...

  4. A Simulated Stream Ecology Study.

    ERIC Educational Resources Information Center

    Zampella, Robert A.

    1979-01-01

    Describes a simulated field experience to study stream ecology in the classroom. Secondary students determine the composition of the stream community, describe the distribution of the benthic invertebrates, and design a food web. (Author/MA)

  5. Impact of broiler slaughter scalding method on processing wastewater stream

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of broiler scalding method on the resulting processing wastewater stream was evaluated. On 3 separate days, 5 to 7 wk old broilers were subjected to a 10 h feed withdrawal, cooped, transported, weighed (live weight), shackled, and then stunned (14.5 V DC, 500 Hz for 10 s) and bled (2 min)...

  6. Open Source Initiative Powers Real-Time Data Streams

    NASA Technical Reports Server (NTRS)

    2014-01-01

    Under an SBIR contract with Dryden Flight Research Center, Creare Inc. developed a data collection tool called the Ring Buffered Network Bus. The technology has now been released under an open source license and is hosted by the Open Source DataTurbine Initiative. DataTurbine allows anyone to stream live data from sensors, labs, cameras, ocean buoys, cell phones, and more.

  7. Studying snails and stream health

    SciTech Connect

    Krause, C.

    1992-01-01

    A type of snail (Elimia) that is abundant in most streams in east Tennessee is noticeably absent in contaminated Oak Ridge streams, indicating a significant level of pollution. Such a snail could serve as a sensitive indicator of and contributor to improved water quality in Oak Ridge streams as remediation programs take effect.

  8. Denitrification of a gas stream

    SciTech Connect

    Tamony, A.E.; Youngson, C.R.

    1981-10-13

    Nitric oxide and other oxides of nitrogen is removed from a gas stream by contacting the gas stream with chlorine in the presence of water in the liquid phase and scrubbing the gas stream with an aqueous mixture of a hydrochloride and a hypochlorite.

  9. A Reflection on Coursestream System: A Virtual Classroom Streaming System Designed for Large Classes

    ERIC Educational Resources Information Center

    Halper, Sachiko; Kelly, Kevin; Chuang, Wen Hao

    2007-01-01

    Delivering courses using streaming media has been an effective vehicle for online education in recent years. At San Francisco State University (SFSU), several courses are offered fully online using streaming media, and each semester over five thousand students take advantage of them. Students can view or listen to live or archived lectures online…

  10. A Reflection on Coursestream System: A Virtual Classroom Streaming System Designed for Large Classes

    ERIC Educational Resources Information Center

    Halper, Sachiko; Kelly, Kevin; Chuang, Wen Hao

    2007-01-01

    Delivering courses using streaming media has been an effective vehicle for online education in recent years. At San Francisco State University (SFSU), several courses are offered fully online using streaming media, and each semester over five thousand students take advantage of them. Students can view or listen to live or archived lectures online

  11. Femtosecond laser disruption of subcellular organelles in a living cell

    NASA Astrophysics Data System (ADS)

    Watanabe, Wataru; Arakawa, Naomi; Matsunaga, Sachihiro; Higashi, Tsunehito; Fukui, Kiichi; Isobe, Keisuke; Itoh, Kazuyoshi

    2004-09-01

    Subcellular organelles in living cells were inactivated by tightly focusing femtosecond laser pulses inside the cells. Photodisruption of a mitochondrion in living cells was experimentally confirmed by stacking three-dimensional confocal images and by restaining of organelles. The viability of the cells after femtosecond laser irradiation was ascertained by impermeability of propidium iodide as well as by the presence of cytoplasmic streaming.

  12. Autonomous Byte Stream Randomizer

    NASA Technical Reports Server (NTRS)

    Paloulian, George K.; Woo, Simon S.; Chow, Edward T.

    2013-01-01

    Net-centric networking environments are often faced with limited resources and must utilize bandwidth as efficiently as possible. In networking environments that span wide areas, the data transmission has to be efficient without any redundant or exuberant metadata. The Autonomous Byte Stream Randomizer software provides an extra level of security on top of existing data encryption methods. Randomizing the data s byte stream adds an extra layer to existing data protection methods, thus making it harder for an attacker to decrypt protected data. Based on a generated crypto-graphically secure random seed, a random sequence of numbers is used to intelligently and efficiently swap the organization of bytes in data using the unbiased and memory-efficient in-place Fisher-Yates shuffle method. Swapping bytes and reorganizing the crucial structure of the byte data renders the data file unreadable and leaves the data in a deconstructed state. This deconstruction adds an extra level of security requiring the byte stream to be reconstructed with the random seed in order to be readable. Once the data byte stream has been randomized, the software enables the data to be distributed to N nodes in an environment. Each piece of the data in randomized and distributed form is a separate entity unreadable on its own right, but when combined with all N pieces, is able to be reconstructed back to one. Reconstruction requires possession of the key used for randomizing the bytes, leading to the generation of the same cryptographically secure random sequence of numbers used to randomize the data. This software is a cornerstone capability possessing the ability to generate the same cryptographically secure sequence on different machines and time intervals, thus allowing this software to be used more heavily in net-centric environments where data transfer bandwidth is limited.

  13. Gas stream cleanup

    SciTech Connect

    Bossart, S.J.; Cicero, D.C.; Zeh, C.M.; Bedick, R.C.

    1990-08-01

    This report describes the current status and recent accomplishments of gas stream cleanup (GSCU) projects sponsored by the Morgantown Energy Technology Center (METC) of the US Department of Energy (DOE). The primary goal of the Gas Stream Cleanup Program is to develop contaminant control strategies that meet environmental regulations and protect equipment in advanced coal conversion systems. Contaminant control systems are being developed for integration into seven advanced coal conversion processes: Pressurized fludized-bed combustion (PFBC), Direct coal-fueled turbine (DCFT), Intergrated gasification combined-cycle (IGCC), Gasification/molten carbonate fuel cell (MCFC), Gasification/solid oxide fuel cell (SOFC), Coal-fueled diesel (CFD), and Mild gasification (MG). These advanced coal conversion systems present a significant challenge for development of contaminant control systems because they generate multi-contaminant gas streams at high-pressures and high temperatures. Each of the seven advanced coal conversion systems incorporates distinct contaminant control strategies because each has different contaminant tolerance limits and operating conditions. 59 refs., 17 figs., 5 tabs.

  14. The LHCb Turbo Stream

    NASA Astrophysics Data System (ADS)

    Benson, Sean; Gligorov, Vladimir; Vesterinen, Mika Anton; Williams, John Michael

    2015-12-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process these datasets, which will limit the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction and discarding the raw event. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses, and this will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015-2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  15. A direct approach for quantifying stream shading

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive stream water temperature causes thermal stress in fish and invertebrates, decreases dissolved oxygen, and encourages bacterial and algal growth. Solar radiation affects stream temperature. Shade cast by riparian vegetation reduces thermal inputs to stream water. Stream shading standards...

  16. PERCENT FOREST ADJACENT TO STREAMS (FUTURE)

    EPA Science Inventory

    The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept pollutants before they reach the stream. Forest cover along streams (RIPFOR) is the percent of total stream length adjacent...

  17. Biotech Outsourcing Strategies cmcBiologics stream

    PubMed Central

    2010-01-01

    Now in its third year, the Biotech Outsourcing Strategies (BOS) meeting organized by Bio2Business took place at the Shuset Conference Centre in Hrsholm, Copenhagen. The focus of this year's event was the demanding and challenging area of chemistry, manufacturing and controls (CMC), and the meeting provided ample opportunity for lively discussion of the key issues surrounding this area. New for the 2010 conference, a biologics-focused lecture stream ran in parallel to the established small molecule stream. Both streams boasted a distinguished panel of keynote speakers who discussed all aspects of CMC from early stage scale-up through late stage clinical development. In addition to the keynote speakers, selected contract research organizations (CROs) gave short presentations on the solutions that they could provide to some of the challenges facing CMC. The meeting attracted more than 150 delegates from leading drug development companies and CRO service providers, and greatly facilitated the forging of new working relationships through pre-arranged one-to-one meetings. Moreover, exhibitions from event sponsors and considerable scheduled networking time over lunch and evening receptions further enhanced the highly productive and interactive nature of the meeting. PMID:20716956

  18. Orbit of the Ophiuchus Stream

    NASA Astrophysics Data System (ADS)

    Sesar, Branimir; Bernard, Edouard J.; Bovy, Jo; Cohen, Judith G.; Caldwell, Nelson; Ness, Melissa; Johnson, Christian I.; Ferguson, Annette M. N.; Martin, Nicolas; Rix, Hans-Walter; Ford Schlafly, Eddie; Pan-Starrs1 Collaboration

    2015-01-01

    Ophiuchus Stream is the most recently discovered stellar stream in the Milky Way (Bernard et al. 2014). Due to its location (5 kpc from the Galactic center) and its puzzling morphology (a thin and short stream, and yet with no visible progenitor), this stream may represent an important piece in our efforts to understand the Galactic potential and the dynamical evolution of accreted structures. In this talk, I will present a followup study of the stream during which we obtained high-quality spectroscopic data on 14 stream member stars using Keck and MMT telescopes. I will show how these newly acquired spectroscopic and existing photometric data enabled us to constrain i) the distance and line-of-sight extent of the stream, ii) the full 3D kinematics of the stream, iii) the chemical properties of the stream and the nature of its progenitor, and iv) the orbit of the stream. I will finish by discussing future prospects in this field in light of the upcoming public release of Pan-STARRS1, Palomar Transient Factory, and GAIA data.

  19. Properties of auditory stream formation

    PubMed Central

    Moore, Brian C. J.; Gockel, Hedwig E.

    2012-01-01

    A sequence of sounds may be heard as coming from a single source (called fusion or coherence) or from two or more sources (called fission or stream segregation). Each perceived source is called a stream. When the differences between successive sounds are very large, fission nearly always occurs, whereas when the differences are very small, fusion nearly always occurs. When the differences are intermediate in size, the percept often flips between one stream and multiple streams, a property called bistability. The flips do not generally occur regularly in time. The tendency to hear two streams builds up over time, but can be partially or completely reset by a sudden change in the properties of the sequence or by switches in attention. Stream formation depends partly on the extent to which successive sounds excite different channels in the peripheral auditory system. However, other factors can play a strong role; multiple streams may be heard when successive sounds are presented to the same ear and have essentially identical excitation patterns in the cochlea. Differences between successive sounds in temporal envelope, fundamental frequency, phase spectrum and lateralization can all induce a percept of multiple streams. Regularities in the temporal pattern of elements within a stream can help in stabilizing that stream. PMID:22371614

  20. Living Nanomachines

    NASA Astrophysics Data System (ADS)

    Carlier, M.-F.; Helfer, E.; Wade, R.; Haraux, F.

    The living cell is a kind of factory on the microscopic scale, in which an assembly of modular machines carries out, in a spatially and temporally coordinated way, a whole range of activities internal to the cell, including the synthesis of substances essential to its survival, intracellular traffic, waste disposal, and cell division, but also activities related to intercellular communication and exchanges with the outside world, i.e., the ability of the cell to change shape, to move within a tissue, or to organise its own defence against attack by pathogens, injury, and so on. These nanomachines are made up of macromolecular assemblies with varying degrees of complexity, forged by evolution, within which work is done as a result of changes in interactions between proteins, or between proteins and nucleic acids, or between proteins and membrane components. All these cell components measure a few nanometers across, so the mechanical activity of these nanomachines all happens on the nanometric scale. The directional nature of the work carried out by biological nanomachines is associated with a dissipation of energy. As examples of protein assemblies, one could mention the proteasome, which is responsible for the degradation of proteins, and linear molecular motors such as actomyosin, responsible for muscle contraction, the dynein-microtubule system, responsible for flagellar motility, and the kinesin-microtubule system, responsible for transport of vesicles, which transform chemical energy into motion. Nucleic acid-protein assemblies include the ribosome, responsible for synthesising proteins, polymerases, helicases, elongation factors, and the machinery of DNA replication and repair; the mitotic spindle is an integrated system involving several of these activities which drive chromosome segregation. The machinery coupling membranes and proteins includes systems involved in the energy metabolism, such as the ATP synthase rotary motor, signalling cascades, endocytosis and phagocytosis complexes, and also dynamic membrane-cytoskeleton complexes which generate protrusion forces involved in cell adhesion and migration. The ideas of molecular recognition and controlled interfaces between biological components provide the underlying mechanisms for biological machinery and networks [1]. Many proteins illustrate this principle by their modular organisation into domains. The juxtaposition of catalytic domains of known function and domains of interaction with different partners leads to the emergence of new biological functions. It can also create threshold mechanisms, or biological switches, by triggering the activity of a given domain only when several partners interact with the regulatory domains. Many of these interaction domains are well understood. They exist inside different proteins, in particular, in cell signaling networks, and could potentially be used as building blocks in the construction of new proteins.

  1. Paleo-ice stream types

    NASA Astrophysics Data System (ADS)

    Kleman, J.; de Angelis, H.; Greenwood, S.

    2010-12-01

    During mapping of the Laurentide and Fennoscandian ice sheet beds we have observed and mapped a large number of paleo-ice streams, including apparently anomalous ice streams ocurring on high shear-stress bed materials, and with little or no topographic guidance. In addition, we have found evidence that in several places in the Canadian Arctic there developed a special category of small ephemeral ice streams during the deglaciation. They indicate flow patterns that are very different from older semi-stable ice streams in the respective areas. These observations of several types of "anomalous" ice streams lead us to think that scientific understanding of ice-stream behaviour has been hampered by an over-simplified terminology that presupposes that ice streams are one phenomenon, largely governed by one set of controls. Instead we hold the view that an understanding of ice-stream behaviour must start with a subdivision of the term "ice stream" into genetically distinct categories, with research focused at clarifying the controls for each category. A tentative classification scheme for paleo-ice streams should comprise at least five different types of ice streams, i/ Classical ice streams which occur on an excessively lubricated bed, i.e. preferably over fine-grained substrate with low permeability. Most of these ice streams terminated in lacustrine or marine water bodies. The numerous Baltic Ice Streams and the Cochrane surges into glacial lakes Agassis/Ojibway are examples of this type, ii/ Semi-stable ice streams which exist in locations where overall ice-sheet geometry favors the occurrence of long-lasting convergent flow, i.e. downstream of saddles in the ice-sheet surface. The Åre - Trondheim area in Scandinavia was likely a site for such an ice stream, iii/ Transient rigid-bed ice streams, which form without obvious topographical or substratum control when thawed spots start to develop under a largely cold-based ice sheet, which then finds itself with a steeper profile than the reduced bed traction can sustain. The unnamed Finnish ice streams that terminate in the Salpausselkä lobes are prime examples, and the Dubawnt ice stream in Keewatin may also be of this type, iiii/ Topographic ice streams, which are constrained by topography and fixed in space but variable in time. The Hudson Strait, Laurentian Channel, and Norwegian Channel ice streams are prime candidates for this type, and iiiii/ Re-equilibration ice streams, which probably develop as a response to rapid calving and breakup of ice in adjacent marine areas. Good examples are the east-trending ice stream on Prince of Wales Island, the small Cap Krusenstern ice stream and numerous ice streams on Baffin Island.

  2. Riparian deforestation, stream narrowing, and loss of stream ecosystem services.

    PubMed

    Sweeney, Bernard W; Bott, Thomas L; Jackson, John K; Kaplan, Louis A; Newbold, J Denis; Standley, Laurel J; Hession, W Cully; Horwitz, Richard J

    2004-09-28

    A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries. PMID:15381768

  3. Riparian deforestation, stream narrowing, and loss of stream ecosystem services

    PubMed Central

    Sweeney, Bernard W.; Bott, Thomas L.; Jackson, John K.; Kaplan, Louis A.; Newbold, J. Denis; Standley, Laurel J.; Hession, W. Cully; Horwitz, Richard J.

    2004-01-01

    A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries. PMID:15381768

  4. Streaming potential revisited

    NASA Astrophysics Data System (ADS)

    Yariv, Ehud; Schnitzer, Ory; Frankel, Itzchak

    2011-11-01

    Streaming-potential phenomena refer to the generation of bulk electric fields by imposed relative motion between a charged solid and the Debye layer adjacent to it. Realistic scenarios are adequately described by the thin-Debye-layer limit ? --> 0 (? denoting the dimensionless Debye thickness), which has been addressed by Cox (1997). Cox's analysis has established that the perturbation to the flow, neglected in the earlier investigations, gives rise to an O (?4) force that dominates that contributed by Maxwell stresses. Cox's theory is founded upon the assumption of O (1) Hartmann and Pclet numbers. We demonstrate that the product of these numbers is actually O (?-2) and accordingly revisit the generic problem of streaming-potential. Electric-current matching between the Debye layer and the bulk provides an inhomogeneous Neumann condition governing the electric field in the latter. This field, in turn, results in a velocity perturbation animated by a Smoluchowski-type slip condition. Owing to dominant convection, the present analysis yields an asymptotic structure considerably simpler than that of Cox (1997): the electro-viscous effect now already appears at O (?2) and is contributed by both Maxwell and viscous stresses. The present paradigm is illustrated for the prototypic problem of a sphere sedimenting in an unbounded fluid, with the resulting drag correction differing from that calculated by Cox (1997).

  5. Stream salamanders as indicators of stream quality in Maryland, USA

    USGS Publications Warehouse

    Southerland, M.T.; Jung, R.E.; Baxter, D.P.; Chellman, I.C.; Mercurio, G.; Volstad, J.H.

    2004-01-01

    Biological indicators are critical to the protection of small, headwater streams and the ecological values they provide. Maryland and other state monitoring programs have determined that fish indicators are ineffective in small streams, where stream salamanders may replace fish as top predators. Because of their life history, physiology, abundance, and ubiquity, stream salamanders are likely representative of biological integrity in these streams. The goal of this study was to determine whether stream salamanders are effective indicators of ecological conditions across biogeographic regions and gradients of human disturbance. During the summers of 2001 and 2002, we intensively surveyed for stream salamanders at 76 stream sites located west of the Maryland Coastal Plain, sites also monitored by the Maryland Biological Stream Survey (MBSS) and City of Gaithersburg. We found 1,584 stream salamanders, including all eight species known in Maryland, using two 15 ? 2 m transects and two 4 m2 quadrats that spanned both stream bank and channel. We performed removal sampling on transects to estimate salamander species detection probabilities, which ranged from 0.67-0.85. Stepwise regressions identified 15 of 52 non-salamander variables, representing water quality, physical habitat, land use, and biological conditions, which best predicted salamander metrics. Indicator development involved (1) identifying reference (non-degraded) and degraded sites (using percent forest, shading, riparian buffer width, aesthetic rating, and benthic macroinvertebrate and fish indices of biotic integrity); (2) testing 12 candidate salamander metrics (representing species richness and composition, abundance, species tolerance, and reproductive function) for their ability to distinguish reference from degraded sites; and (3) combining metrics into an index that effectively discriminated sites according to known stream conditions. Final indices for Highlands, Piedmont, and Non-Coastal Plain regions comprised four metrics: number of species, number of salamanders, number of intolerant salamanders, and number of adult salamanders, producing classification efficiencies between 87% and 90%. Partial validation of these indices was obtained when a test of the number of salamanders metric produced an 82% correct classification of 618 MBSS sites surveyed in 1995-97. This study supports the use of stream salamander monitoring and a composite stream salamander index of biotic integrity (SS-IBI) to determine stream quality in Maryland.

  6. The Phoenix Stream: A Cold Stream in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Balbinot, E.; Yanny, B.; Li, T. S.; Santiago, B.; Marshall, J. L.; Finley, D. A.; Pieres, A.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; March, M.; Martini, P.; Miquel, R.; Nichol, R. C.; Ogando, R.; Romer, A. K.; Sanchez, E.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D.; Walker, A. R.; The DES Collaboration

    2016-03-01

    We report the discovery of a stellar stream in the Dark Energy Survey Year 1 (Y1A1) data. The discovery was made through simple color–magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color–magnitude space, we find that a stellar population with age τ = 11.5 ± 0.5 Gyr and [Fe/H] < ‑1.6, located 17.5 ± 0.9 kpc from the Sun, gives an adequate description of the stream stellar population. The stream is detected over an extension of 8.°1 (2.5 kpc) and has a width of ∼54 pc assuming a Gaussian profile, indicating that a globular cluster (GC) is a probable progenitor. There is no known GC within 5 kpc that is compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities (ODs) along the stream, however, no obvious counterpart-bound stellar system is visible in the coadded images. We also find ODs along the stream that appear to be symmetrically distributed—consistent with the epicyclic OD scenario for the formation of cold streams—as well as a misalignment between the northern and southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe OD.

  7. Morphology of a Wetland Stream

    PubMed

    Jurmu; Andrle

    1997-11-01

    / Little attention has been paid to wetland stream morphology in the geomorphological and environmental literature, and in the recently expanding wetland reconstruction field, stream design has been based primarily on stream morphologies typical of nonwetland alluvial environments. Field investigation of a wetland reach of Roaring Brook, Stafford, Connecticut, USA, revealed several significant differences between the morphology of this stream and the typical morphology of nonwetland alluvial streams. Six morphological features of the study reach were examined: bankfull flow, meanders, pools and riffles, thalweg location, straight reaches, and cross-sectional shape. It was found that bankfull flow definitions originating from streams in nonwetland environments did not apply. Unusual features observed in the wetland reach include tight bends and a large axial wavelength to width ratio. A lengthy straight reach exists that exceeds what is typically found in nonwetland alluvial streams. The lack of convex bank point bars in the bends, a greater channel width at riffle locations, an unusual thalweg location, and small form ratios (a deep and narrow channel) were also differences identified. Further study is needed on wetland streams of various regions to determine if differences in morphology between alluvial and wetland environments can be applied in order to improve future designs of wetland channels.KEY WORDS: Stream morphology; Wetland restoration; Wetland creation; Bankfull; Pools and riffles; Meanders; Thalweg PMID:9336489

  8. The role of stream biota in watershed processes

    SciTech Connect

    Cummins, K.W.

    1986-06-01

    The linkage between stream biota and the bank (riparian) vegetation is an essential and tight association in small (orders 1 to 4), running water systems. This critical association can be observed in watersheds covering the full range of thermal and hydrologic patterns. Coarse particulate detritus derived primarily from terrestrial streamside vegetation is processed in the stream channel - that is, converted to fine particulate detritus, respired CO/sub 2/, and living organism biomass. The terrestrial-stream interchange is a two way process associated with seasonal temperature and flow cycles. Thus stream organisms utilizing detritus ultimately of terrestrial origin, change both the size and quality of the particulate organics. This material generally reaches a higher quality condition more rapidly than that confined to the soil litter. In addition to the two-way interaction that is processing terrestrially-derived litter and yielding qualitatively changed material to the flood plain at high flows, the stream biota play a significant role in the entrainment and retention of dissolved and particulate organics within a given stream reach.

  9. 1994 MARYLAND BIOLOGICAL STREAM SURVEY STREAM HABITAT ASSESSMENT (HABIT94)

    EPA Science Inventory

    The Maryland Biological Stream Survey (MBSS) is a multi-year probability-based sampling program designed to assess the status of biological resources in non-tidal streams of Maryland. The MBSS study area comprises eighteen drainage basins across the state of Maryland, providing ...

  10. Analyzing indicators of stream health for Minnesota streams

    USGS Publications Warehouse

    Singh, U.; Kocian, M.; Wilson, B.; Bolton, A.; Nieber, J.; Vondracek, B.; Perry, J.; Magner, J.

    2005-01-01

    Recent research has emphasized the importance of using physical, chemical, and biological indicators of stream health for diagnosing impaired watersheds and their receiving water bodies. A multidisciplinary team at the University of Minnesota is carrying out research to develop a stream classification system for Total Maximum Daily Load (TMDL) assessment. Funding for this research is provided by the United States Environmental Protection Agency and the Minnesota Pollution Control Agency. One objective of the research study involves investigating the relationships between indicators of stream health and localized stream characteristics. Measured data from Minnesota streams collected by various government and non-government agencies and research institutions have been obtained for the research study. Innovative Geographic Information Systems tools developed by the Environmental Science Research Institute and the University of Texas are being utilized to combine and organize the data. Simple linear relationships between index of biological integrity (IBI) and channel slope, two-year stream flow, and drainage area are presented for the Redwood River and the Snake River Basins. Results suggest that more rigorous techniques are needed to successfully capture trends in IBI scores. Additional analyses will be done using multiple regression, principal component analysis, and clustering techniques. Uncovering key independent variables and understanding how they fit together to influence stream health are critical in the development of a stream classification for TMDL assessment.

  11. Stream Water and Sediment Phosphorus Equilibrium Concentrations in Ozark Streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little information is broadly available on the fate and transport of dissolved phosphorus (DP) in streams draining agricultural and urban catchments, although in-stream processes might have a substantial influence on downstream transport. This study evaluated sediment-water P equilibrium concentrat...

  12. ASSESSING STREAM BED STABILITY AND EXCESS SEDIMENTATION IN MOUNTAIN STREAMS

    EPA Science Inventory

    Land use and resource exploitation in headwaters catchments?such as logging, mining, and road building?often increase sediment supply to streams, potentially causing excess sedimentation. Decreases in mean substrate size and increases in fine stream bed sediments can lead to inc...

  13. 1995 MARYLAND BIOLOGICAL STREAM SURVEY STREAM HABITAT ASSESSMENT (HABIT95)

    EPA Science Inventory

    The Maryland Biological Stream Survey (MBSS) is a multi-year probability-based sampling program designed to assess the status of biological resources in non-tidal streams of Maryland. The MBSS study area comprises eighteen drainage basins across the state of Maryland, providing ...

  14. Human impacts to mountain streams

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen

    2006-09-01

    Mountain streams are here defined as channel networks within mountainous regions of the world. This definition encompasses tremendous diversity of physical and biological conditions, as well as history of land use. Human effects on mountain streams may result from activities undertaken within the stream channel that directly alter channel geometry, the dynamics of water and sediment movement, contaminants in the stream, or aquatic and riparian communities. Examples include channelization, construction of grade-control structures or check dams, removal of beavers, and placer mining. Human effects can also result from activities within the watershed that indirectly affect streams by altering the movement of water, sediment, and contaminants into the channel. Deforestation, cropping, grazing, land drainage, and urbanization are among the land uses that indirectly alter stream processes. An overview of the relative intensity of human impacts to mountain streams is provided by a table summarizing human effects on each of the major mountainous regions with respect to five categories: flow regulation, biotic integrity, water pollution, channel alteration, and land use. This table indicates that very few mountains have streams not at least moderately affected by land use. The least affected mountainous regions are those at very high or very low latitudes, although our scientific ignorance of conditions in low-latitude mountains in particular means that streams in these mountains might be more altered than is widely recognized. Four case studies from northern Sweden (arctic region), Colorado Front Range (semiarid temperate region), Swiss Alps (humid temperate region), and Papua New Guinea (humid tropics) are also used to explore in detail the history and effects on rivers of human activities in mountainous regions. The overview and case studies indicate that mountain streams must be managed with particular attention to upstream/downstream connections, hillslope/channel connections, process domains, physical and ecological roles of disturbance, and stream resilience.

  15. Live Video and IP-TV

    NASA Astrophysics Data System (ADS)

    Merani, Maria Luisa; Saladino, Daniela

    This Chapter aims at providing a comprehensive insight into the most recent advances in the field of P2P architectures for video broadcasting, focusing on live video streaming P2P live video streaming . After introducing a classification of P2P video solutions, the first part of the Chapter provides an overview of the most interesting P2P IP-TV P2P IP-TV systems currently available over the Internet. It also concentrates on the process of data diffusion within the P2P overlay and complements this view with some measurements that highlight the most salient features of P2P architectures. The second part of the Chapter completes the view, bringing up the modeling efforts to capture the main characteristics and limits of P2P streaming systems, both analytically and numerically. The Chapter is closed by a pristine look at some challenging, open questions, with a specific emphasis on the adoption of network coding in P2P streaming solutions.

  16. Cross-channel collaborations in peer-to-peer streaming

    NASA Astrophysics Data System (ADS)

    Li, Hongchao; Li, Kang

    2007-01-01

    Peer-to-Peer(P2P) streaming has become a very popular technique to realize live media broadcast over the Internet. Most previous research of P2P streaming focuses on the delivery of a single media stream (called a channel). The widely deployed implementations, however, all concurrently offer multiple channels through their P2P networks. This paper investigates the overlay organization for multi-channel P2P streaming systems through modeling and simulations. In particular, this paper examines the potential collaborations among nodes across multiple channels. Our investigation shows that collaboration among nodes across different channels can improve the overall performance of the multi-channel P2P streaming system. However, the collaboration strategies need to be carefully selected. Simple collaboration strategies, such as treating collaborative nodes (those "borrowed" from other channels) the same as a channel's native nodes (those playing the channel), tend to have marginal or even negative effects on the whole system performance. This result is contrary to common impression - the larger population the better performance of P2P system - and we found that this is caused by the differences between P2P streaming and traditional P2P file-sharing systems. Furthermore, this paper proposes a set of simple strategies that controls the upload-download ratio of collaborative nodes. We showed that this set of strategies produces a much better collaboration result for multi-channel P2P streaming systems. Although only a preliminary study, we believe the results will promote further investigation on the topic of multi-channel P2P streaming.

  17. Save Our Streams and Waterways.

    ERIC Educational Resources Information Center

    Indiana State Dept. of Education, Indianapolis. Center for School Improvement and Performance.

    Protection of existing water supplies is critical to ensuring good health for people and animals alike. This program is aligned with the Izaak Walton League of American's Save Our Streams program which is based on the concept that students can greatly improve the quality of a nearby stream, pond, or river by regular visits and monitoring. The

  18. We All Stream for Video

    ERIC Educational Resources Information Center

    Technology & Learning, 2008

    2008-01-01

    More than ever, teachers are using digital video to enhance their lessons. In fact, the number of schools using video streaming increased from 30 percent to 45 percent between 2004 and 2006, according to Market Data Retrieval. Why the popularity? For starters, video-streaming products are easy to use. They allow teachers to punctuate lessons with…

  19. Industrial-Strength Streaming Video.

    ERIC Educational Resources Information Center

    Avgerakis, George; Waring, Becky

    1997-01-01

    Corporate training, financial services, entertainment, and education are among the top applications for streaming video servers, which send video to the desktop without downloading the whole file to the hard disk, saving time and eliminating copyrights questions. Examines streaming video technology, lists ten tips for better net video, and ranks

  20. Living with an Arrhythmia

    MedlinePLUS

    ... from the NHLBI on Twitter. Living With an Arrhythmia Many arrhythmias are harmless. It's common to have an occasional ... heartbeat or mild palpitations . People who have harmless arrhythmias can live healthy lives. They usually don't ...

  1. Stream processing health card application.

    PubMed

    Polat, Seda; Gndem, Taflan Imre

    2012-10-01

    In this paper, we propose a data stream management system embedded to a smart card for handling and storing user specific summaries of streaming data coming from medical sensor measurements and/or other medical measurements. The data stream management system that we propose for a health card can handle the stream data rates of commonly known medical devices and sensors. It incorporates a type of context awareness feature that acts according to user specific information. The proposed system is cheap and provides security for private data by enhancing the capabilities of smart health cards. The stream data management system is tested on a real smart card using both synthetic and real data. PMID:22127523

  2. FireHose Streaming Benchmarks

    SciTech Connect

    2015-01-27

    The FireHose Streaming Benchmarks are a suite of stream-processing benchmarks defined to enable comparison of streaming software and hardware, both quantitatively vis-a-vis the rate at which they can process data, and qualitatively by judging the effort involved to implement and run the benchmarks. Each benchmark has two parts. The first is a generator which produces and outputs datums at a high rate in a specific format. The second is an analytic which reads the stream of datums and is required to perform a well-defined calculation on the collection of datums, typically to find anomalous datums that have been created in the stream by the generator. The FireHose suite provides code for the generators, sample code for the analytics (which users are free to re-implement in their own custom frameworks), and a precise definition of each benchmark calculation.

  3. PERCENT AGRICULTURE ADJACENT TO STREAMS (FUTURE)

    EPA Science Inventory

    The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept pollutants before they reach the stream. High percentages of agriculture along streams increase the likelihood of elevated ...

  4. Dynamical modeling of tidal streams

    SciTech Connect

    Bovy, Jo

    2014-11-01

    I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its 'track') in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of 'orphan' streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.

  5. Dynamical Modeling of Tidal Streams

    NASA Astrophysics Data System (ADS)

    Bovy, Jo

    2014-11-01

    I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its "track") in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of "orphan" streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.

  6. Role of monitoring in stream restoration

    EPA Science Inventory

    Hydrology and dissolved organic carbon availability dictate nitrate dynamics in urban streams. So to improve N uptake, restore streams to: Slow down stream flow Add organic carbon Reconnect floodplain hydrology and riparian zones

  7. Electronic Eye: Streaming Video On-Demand.

    ERIC Educational Resources Information Center

    Meulen, Kathleen

    2002-01-01

    Discusses the use of on-demand streaming video in school libraries. Explains how streaming works, considers advantages and technical issues, and describes products from three companies that are pioneering streaming in the educational video market. (LRW)

  8. Lexical influences on auditory streaming.

    PubMed

    Billig, Alexander J; Davis, Matthew H; Deeks, John M; Monstrey, Jolijn; Carlyon, Robert P

    2013-08-19

    Biologically salient sounds, including speech, are rarely heard in isolation. Our brains must therefore organize the input arising from multiple sources into separate "streams" and, in the case of speech, map the acoustic components of the target signal onto meaning. These auditory and linguistic processes have traditionally been considered to occur sequentially and are typically studied independently [1, 2]. However, evidence that streaming is modified or reset by attention [3], and that lexical knowledge can affect reports of speech sound identity [4, 5], suggests that higher-level factors may influence perceptual organization. In two experiments, listeners heard sequences of repeated words or acoustically matched nonwords. After several presentations, they reported that the initial /s/ sound in each syllable formed a separate stream; the percept then fluctuated between the streamed and fused states in a bistable manner. In addition to measuring these verbal transformations, we assessed streaming objectively by requiring listeners to detect occasional targets-syllables containing a gap after the initial /s/. Performance was better when streaming caused the syllables preceding the target to transform from words into nonwords, rather than from nonwords into words. Our results show that auditory stream formation is influenced not only by the acoustic properties of speech sounds, but also by higher-level processes involved in recognizing familiar words. PMID:23891107

  9. Lexical Influences on Auditory Streaming

    PubMed Central

    Billig, AlexanderJ.; Davis, MatthewH.; Deeks, JohnM.; Monstrey, Jolijn; Carlyon, RobertP.

    2013-01-01

    Summary Biologically salient sounds, including speech, are rarely heard in isolation. Our brains must therefore organize the input arising from multiple sources into separate streams and, in the case of speech, map the acoustic components of the target signal onto meaning. These auditory and linguistic processes have traditionally been considered to occur sequentially and are typically studied independently [1, 2]. However, evidence that streaming is modified or reset by attention [3], and that lexical knowledge can affect reports of speech sound identity [4, 5], suggests that higher-level factors may influence perceptual organization. In two experiments, listeners heard sequences of repeated words or acoustically matched nonwords. After several presentations, they reported that the initial /s/ sound in each syllable formed a separate stream; the percept then fluctuated between the streamed and fused states in a bistable manner. In addition to measuring these verbal transformations, we assessed streaming objectively by requiring listeners to detect occasional targetssyllables containing a gap after the initial /s/. Performance was better when streaming caused the syllables preceding the target to transform from words into nonwords, rather than from nonwords into words. Our results show that auditory stream formation is influenced not only by the acoustic properties of speech sounds, but also by higher-level processes involved in recognizing familiar words. PMID:23891107

  10. Scientific Discovery within Data Streams

    SciTech Connect

    Cowell, Andrew J.; Havre, Susan L.; May, Richard A.; Sanfilippo, Antonio P.

    2005-04-25

    This paper discusses our recent work across a number of disciplines, leading to a concept for a next generation analytical environment for scientific discovery within continuous, time-varying data-streams. First, we have created a stream-processing engine that processes multiple streams of interest. An analyst, via a client interface, reviews the data-stream format and specifies upstream filtering to define stream tokens of interest, leading to a highly specialized collection of time-variant material. We envision using this collection to drive an existing system that visualizes thematic variations over time across a corpus of information. This ThemeRiver helps analysts discern trends, relationships, anomalies, and structure in the data. Further, we make use of a number of technologies that allow us to investigate these elements in ambient environments that surround the user, placing them within their data. We discuss the HI-SPACE (Human Information Space) as a tool for bringing together the most desirable aspects of both physical and electronic information spaces to enhance the ability to interact with information, promote group dialog, and to facilitate group interaction with information to solve complex tasks. Here, we introduce a concept that combines these approaches to produce an advanced analytical environment for data stream analysis that provides a collaborative, ambient environment for scientific discovery in data-streams.

  11. Flexible server architecture for resource-optimal presentation of Internet multimedia streams to the client

    NASA Astrophysics Data System (ADS)

    Boenisch, Holger; Froitzheim, Konrad

    1999-12-01

    The transfer of live media streams such as video and audio over the Internet is subject to several problems, static and dynamic by nature. Important quality of service (QoS) parameters do not only differ between various receivers depending on their network access, service provider, and nationality, the QoS is also variable in time. Moreover the installed receiver base is heterogeneous with respect to operating system, browser or client software, and browser version. We present a new concept for serving live media streams. It is not longer based on the current one-size-fits all paradigm, where the server offers just one stream. Our compresslet system takes the opposite approach: it builds media streams `to order' and `just in time'. Every client subscribing to a media stream uses a servlet loaded into the media server to generate a tailored data stream for his resources and constraints. The server is designed such that commonly used components for media streams are computed once. The compresslets use these prefabricated components, code additional data if necessary, and construct the data stream based on the dynamic available QoS and other client constraints. A client-specific encoding leads to resource- optimal presentation that is especially useful for the presentation of complex multimedia documents on a variety of output devices.

  12. Experimental and numerical investigation of Acoustic streaming (Eckart streaming)

    NASA Astrophysics Data System (ADS)

    Dridi, Walid; Botton, Valery; Henry, Daniel; Ben Hadid, Hamda

    The application of sound waves in the bulk of a fluid can generate steady or quasi-steady flows reffered to as Acoustic streaming flows. We can distinguish two kind of acoustic streaming: The Rayleigh Streaming is generated when a standing acoustic waves interfere with solid walls to give birth to an acoustic boundary layer. Steady recirculations are then driven out of the boundary layer and can be used in micro-gravity, where the free convection is too weak or absent, to enhance the convective heat or mass transfer and cooling the electronic devises [1]. The second kind is the Eckart streaming, which is a flow generated far from the solid boundaries, it can be used to mix a chemical solutions [2], and to drive a viscous liquids in channels [3-4], in micro-gravity area. Our study focuses on the Eckart streaming configuration, which is investigated both numerical and experimental means. The experimental configuration is restricted to the case of a cylindrical non-heated cavity full of water or of a water+glycerol mixture. At the middle of one side of the cavity, a plane ultrasonic transducer generates a 2MHz wave; an absorber is set at the opposite side of the cavity to avoid any reflections. The velocity field is measured with a standard PIV system. [1] P. Vainshtein, M. Fichman and C. Gutfinger, "Acoustic enhancement of heat transfer between two parallel plates", International Journal of Heat and Mass Transfert, 1995, 38(10), 1893. [2] C. Suri, K. Tekenaka, H. Yanagida, Y. Kojima and K. Koyama, "Chaotic mixing generated by acoustic streaming", Ultrasonics, 2002, 40, 393 [3] O.V. Rudenko and A.A. Sukhorukov, "Nonstationnary Eckart streaming and pumping of liquid in ultrasonic field", Acoustical Physics, 1998, 44, 653. [4] Kenneth D. Frampton, Shawn E. Martin and Keith Minor, "The scaling of acoustic streaming for application in micro-fluidic devices", Applied Acoustics, 2003, 64,681

  13. Mixing of Supersonic Streams

    NASA Technical Reports Server (NTRS)

    Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

    1998-01-01

    The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 19 equivalent rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

  14. Mixing of Supersonic Streams

    NASA Technical Reports Server (NTRS)

    Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

    1998-01-01

    The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 10 rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

  15. Wood in New Zealand's Native Forest Streams. Recent Advances

    NASA Astrophysics Data System (ADS)

    Mark, M. A.; Davies-Colley, R.

    2005-05-01

    We conducted a series of research projects to investigate the importance of wood in native forested streams of New Zealand. We examined abundance and geomorphic role of wood in 18 pristine native forest streams (channel width: 3-6 m) throughout New Zealand. Forest type and geographic location had no discernable influence on wood abundance, possibly reflecting the confounding influences of local features (e.g., tree fall regime) and methodology (`snap-shot' survey of a dynamic system). Number (18-66 per 100 m) and dead wood volume (85-470 m3 ha-1) of stream logs were at the high end of the international range. Living trees contributed up to 25% of total wood, and tree ferns were strongly represented (up to 11% of volume). The largest 10% of pieces contributed 75% of the total volume. The importance of the large wood pieces (>10 m3) was explored further with surveys within that watershed containing the site with the greatest wood volume. The largest pieces were rare but seemed relatively uniformly distributed. To explore the biological consequences of stream wood, we studied use of wood-related micro-habitat by the crayfish (Paranephrops planifrons White). Our findings suggest that wood is an important component of New Zealand's forested stream ecosystems.

  16. MVSP: multithreaded VLIW stream processor

    NASA Astrophysics Data System (ADS)

    Sardashti, Somayeh; Ghasemi, Hamid Reza; Fatemi, Omid

    2006-02-01

    Stream processing is a new trend in computer architecture design which fills the gap between inflexible special-purpose media architectures and programmable architectures with low computational ability for media processing. Stream processors are designed for computationally intensive media applications characterized by high data parallelism and producer-consumer locality with little global data reuse. In this paper, we propose a new stream processor, named MVSP1. This processor is a programmable stream processor based on Imagine [1]. MVSP exploits TLP2, DLP 3, SP 4 and ILP 5 parallelisms inherent in media applications. Full simulator of MVSP has been implemented and several media workloads composed of EEMBC [2] benchmarks have been applied. The simulation results show the performance and functional unit utilization improvements of more than two times in comparison with Imagine processor.

  17. FireHose Streaming Benchmarks

    Energy Science and Technology Software Center (ESTSC)

    2015-01-27

    The FireHose Streaming Benchmarks are a suite of stream-processing benchmarks defined to enable comparison of streaming software and hardware, both quantitatively vis-a-vis the rate at which they can process data, and qualitatively by judging the effort involved to implement and run the benchmarks. Each benchmark has two parts. The first is a generator which produces and outputs datums at a high rate in a specific format. The second is an analytic which reads the streammore » of datums and is required to perform a well-defined calculation on the collection of datums, typically to find anomalous datums that have been created in the stream by the generator. The FireHose suite provides code for the generators, sample code for the analytics (which users are free to re-implement in their own custom frameworks), and a precise definition of each benchmark calculation.« less

  18. Internet stream synchronization using Concord

    NASA Astrophysics Data System (ADS)

    Sreenan, Cormac J.; Narendran, B.; Agrawal, Prathima; Shivakumar, Narayanan

    1996-03-01

    Using packet networks to transport multimedia introduces delay variations within and across streams, necessitating synchronization at the receiver. This requires stream data to be buffered prior to presentation, which also increases its total end to end delay. Concord recognizes that applications may wish to influence the underlying synchronization policy in terms of its effect on quality of service. It provides a single framework for synchronization within and across streams and employs an application specific tradeoff between packet losses, delay and inter- stream skew. We present a new predictive approach for synchronization and a selection of results from an extensive evaluation of Concord for use in the Internet. A trace driven simulator is used, allowing a direct comparison with alternative approaches. We demonstrate that Concord can operate with lower maximum delay and less variation in total end to end delay, which in turn can allow receiver buffer requirements to be reduced.

  19. Video streaming into the mainstream.

    PubMed

    Garrison, W

    2001-12-01

    Changes in Internet technology are making possible the delivery of a richer mixture of media through data streaming. High-quality, dynamic content, such as video and audio, can be incorporated into Websites simply, flexibly and interactively. Technologies such as G3 mobile communication, ADSL, cable and satellites enable new ways of delivering medical services, information and learning. Systems such as Quicktime, Windows Media and Real Video provide reliable data streams as video-on-demand and users can tailor the experience to their own interests. The Learning Development Centre at the University of Portsmouth have used streaming technologies together with e-learning tools such as dynamic HTML, Flash, 3D objects and online assessment successfully to deliver on-line course content in economics and earth science. The Lifesign project--to develop, catalogue and stream health sciences media for teaching--is described and future medical applications are discussed. PMID:11802705

  20. MODELING PLUMES IN SMALL STREAMS

    EPA Science Inventory

    Pesticides accumulate on land surfaces from agricultural, commercial, and domestic application, and wash into streams and rivers during dry and wet weather. Flood water retention basins or structures often collect this contaminated runoff, providing intermediate storage and limit...

  1. Optimal placement of off-stream water sources for ephemeral stream recovery

    USGS Publications Warehouse

    Rigge, Matthew B.; Smart, Alexander; Wylie, Bruce

    2013-01-01

    Uneven and/or inefficient livestock distribution is often a product of an inadequate number and distribution of watering points. Placement of off-stream water practices (OSWP) in pastures is a key consideration in rangeland management plans and is critical to achieving riparian recovery by improving grazing evenness, while improving livestock performance. Effective OSWP placement also minimizes the impacts of livestock use radiating from OSWP, known as the “piosphere.” The objective of this study was to provide land managers with recommendations for the optimum placement of OSWP. Specifically, we aimed to provide minimum offset distances of OSWP to streams and assess the effective range of OSWP using Normalized Difference Vegetation Index (NDVI) values, an indicator of live standing crop. NDVI values were determined from a time-series of Satellite Pour l'Observation de la Terre (SPOT) 20-m images of western South Dakota mixed-grass prairie. The NDVI values in ephemeral stream channels (in-channel) and uplands were extracted from pre- and post-OSWP images taken in 1989 and 2010, respectively. NDVI values were normalized to a reference imagine and subsequently by ecological site to produce nNDVI. Our results demonstrate a significant (P 2 = 0.49, P = 0.05) and increased with average distance to OSWP in a pasture (R2 = 0.43, P = 0.07). Piospheric reduction in nNDVI was observed within 200 m of OSWP, occasionally overlapping in-channel areas. The findings of this study suggest placement of OSWP 200 to 1 250 m from streams to achieve optimal results. These results can be used to increase grazing efficiency by effectively placing OSWP and insure that piospheres do not overlap ecologically important in-channel areas.

  2. Capture zone between two streams

    NASA Astrophysics Data System (ADS)

    Intaraprasong, Trin; Zhan, Hongbin

    2007-05-01

    SummaryWe have investigated stream-aquifer interaction with a single pumping well in an aquifer bounded by two parallel nearby streams. This study presents steady-state semi-analytical solutions to calculate the fraction of water withdrawal from two streams. Potential theory is used to describe the capture zone between two streams when low-permeability streambeds are not present. Steady-state flow equations in the aquifer and two streambeds are solved following rigorous mass balance requirements if low-permeability streambeds are present. When the low-permeability streambeds are not present and the regional flow exists between two streams, this study finds that the maximal capture size without extracting water from the down-gradient stream decreases with the normalized well location in an approximately linear fashion. Furthermore, the normalized flux from the up-gradient stream decreases with the normalized well location faster than the linear fashion. When the low-permeability streambeds exist and the regional flow is neglected, the normalized flux across either streambed varies with the normalized well location in a linear function. Furthermore, the magnitude of the slope of that function is nearly unity when the hydraulic conductance ratio of the two streambeds is one and is less than unity when the hydraulic conductance ratio of the two streambeds is either greater or smaller than one. When the normalized well location with equal fluxes from two streams versus the hydraulic conductance ratio of the two streambeds are plotted semi-logarithmically, we observed a segmented curve including a steep segment at the beginning, followed by a flat segment, and a final steep segment.

  3. Producing a Live HDTV Program from Space

    NASA Technical Reports Server (NTRS)

    Grubbs, Rodney; Fontanot, Carlos; Hames, Kevin

    2007-01-01

    By the year 2000, NASA had flown HDTV camcorders on three Space Shuttle missions: STS-95, STS-93 and STS-99. All three flights of these camcorders were accomplished with cooperation from the Japanese space agency (then known as NASDA and now known as JAXA). The cameras were large broadcast-standard cameras provided by NASDA and flight certified by both NASA and NASDA. The high-definition video shot during these missions was spectacular. Waiting for the return of the tapes to Earth emphasized the next logical step: finding a way to downlink the HDTV live from space. Both the Space Shuttle and the International Space Station (ISS) programs were interested in live HDTV from space, but neither had the resources to fully fund the technology. Technically, downlinking from the ISS was the most effective approach. Only when the Japanese broadcaster NHK and the Japanese space agency expressed interest in covering a Japanese astronaut's journey to the ISS did the project become possible. Together, JAXA and NHK offered equipment, technology, and funding toward the project. In return, NHK asked for a live HDTV downlink during one of its broadcast programs. NASA and the ISS Program sought a US partner to broadcast a live HDTV program and approached the Discovery Channel. The Discovery Channel had proposed a live HDTV project in response to NASA's previous call for offers. The Discovery Channel agreed to provide addItional resources. With the final partner in place, the project was under way. Engineers in the Avionics Systems Division at NASA's Johnson Space Center (JSC) had already studied the various options for downlinking HDTV from the ISS. They concluded that the easiest way was to compress the HDTV so that the resulting data stream would "look" like a payload data stream. The flight system would consist of a professional HDTV camcorder with live HD-SDI output, an HDTV MPEG-2 encoder, and a packetizer/protocol converter.

  4. [Application and effectiveness of soil bioengineering in ecological restoration of stream bank].

    PubMed

    Li, Xiaoping; Zhang, Liquan

    2006-09-01

    Soil bioengineering is a kind of engineering by using living plant materials to construct the structures with some engineering and ecological functions, which can provide an effective means for the slope stabilization and site restoration of stream banks. In this paper, the principles of soil bioengineering, basic planting methods, live stakes, live fascines, brush layering, and integrated technologies were discussed in brief, and the first demo project of soil engineering in ecological restoration of stream bank in our country was introduced. After 10-month project implementation, significant effectiveness was obtained on slope stability, habitat improvement, and ecological restoration of stream banks. It was concluded that the approach could be widely applied in ecological restoration of all kinds of slopes in China. PMID:17147185

  5. Miscellaneous streams best management practices (BMP) report

    SciTech Connect

    Lueck, K.J., Westinghouse Hanford

    1996-07-24

    The Washington State Department of Ecology (Ecology) and U.S. Department of Energy Consent Order No. DE 91NM-177 (Consent Order) lists regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code (WAC) 173-216 (`State Waste Discharge Permit Program`) or WAC 173-218 (`Washington Underground Injection Control Program`) where applicable. Hanford Site liquid effluent streams discharging to the soil column are categorized as Phase I and Phase II Streams, and Miscellaneous Streams. There were originally 33 Phase I and Phase II Streams, however some of these streams have been eliminated. Miscellaneous Streams are those liquid effluent streams discharged to the ground that are not categorized as Phase I or Phase II Streams, and are subject to the requirements of several milestones identified in the Consent Order. The three criteria for identifying streams that are potentially affecting groundwater are: (1) streams discharging to surface contaminated areas (referred to as category `b` streams); (2) potentially contaminated streams (referred to as category `c` streams); and (3) streams discharging within 91 meters (300 feet) of a contaminated crib, ditch, or trench (referred to as category `d` streams). Miscellaneous Streams that meet any of these criteria must be evaluated for application of best management practices (BMP). The purpose of this report is to provide the best management practice preferred alternative. The list of BMP streams has been revised since the original submittal. Several streams from the original list of BMP streams have already been eliminated through facility upgrades, reduction of steam usage, and facility shutdowns. This document contains a description of the changes to the list of BMP streams, applicable definitions and regulatory requirements and possible alternatives, and a schedule for implementing the preferred alternatives.

  6. Stream bed organic carbon and biotic integrity.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Allochthonous organic matter provides a basis for some stream ecosystems. Channel incision, which is a common result of anthropogenic impacts on watersheds and stream channels, may deplete stream bed C stores due to erosion, less frequent hydrologic exchanges between stream and floodplain, and remov...

  7. Unique Challenges to (Federal) Enterprise Streaming

    NASA Technical Reports Server (NTRS)

    Walls, Bryan

    2006-01-01

    Enterprise streaming has different parameters than consumer Streaming. The government enterprise has some differences on top of that. I'd like to highlight some issues shared by the Federal government as a whole, with a closer look at streaming within NASA. Then we'll look at NASA's strategy for streaming.

  8. The Dynamics of Star Stream Gaps

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.

    2013-10-01

    A massive object crossing a narrow stream of stars orbiting in the halo of the galaxy induces velocity changes both along and transverse to the stream that can lead to the development of a visible gap. For a stream narrow relative to its orbital radius, the stream crossing time is sufficiently short that the impact approximation can be used to derive the changes in angular momenta and radial actions along the star stream. The epicyclic approximation is used to calculate the evolution of the density of the stream as it orbits around in a galactic potential. Analytic expressions are available for a point mass, however, the general expressions are easily numerically evaluated for perturbing objects with arbitrary density profiles. With a simple allowance for the velocity dispersion of the stream, moderately warm streams can be modeled. The predicted evolution agrees well with the outcomes of simulations of stellar streams for streams with widths up to 1% of the orbital radius of the stream. The angular momentum distribution within the stream shears out gaps with time, further reducing the visibility of streams, although the size of the shear effect requires more detailed simulations that account for the creation of the stream. An illustrative model indicates that shear will set a lower limit of a few times the stream width for the length of gaps that persist. In general, the equations are useful for dynamical insights into the development of stream gaps and their measurement.

  9. THE DYNAMICS OF STAR STREAM GAPS

    SciTech Connect

    Carlberg, R. G.

    2013-10-01

    A massive object crossing a narrow stream of stars orbiting in the halo of the galaxy induces velocity changes both along and transverse to the stream that can lead to the development of a visible gap. For a stream narrow relative to its orbital radius, the stream crossing time is sufficiently short that the impact approximation can be used to derive the changes in angular momenta and radial actions along the star stream. The epicyclic approximation is used to calculate the evolution of the density of the stream as it orbits around in a galactic potential. Analytic expressions are available for a point mass, however, the general expressions are easily numerically evaluated for perturbing objects with arbitrary density profiles. With a simple allowance for the velocity dispersion of the stream, moderately warm streams can be modeled. The predicted evolution agrees well with the outcomes of simulations of stellar streams for streams with widths up to 1% of the orbital radius of the stream. The angular momentum distribution within the stream shears out gaps with time, further reducing the visibility of streams, although the size of the shear effect requires more detailed simulations that account for the creation of the stream. An illustrative model indicates that shear will set a lower limit of a few times the stream width for the length of gaps that persist. In general, the equations are useful for dynamical insights into the development of stream gaps and their measurement.

  10. Cytoplasmic streaming affects gravity-induced amyloplast sedimentation in maize coleoptiles

    NASA Technical Reports Server (NTRS)

    Sack, F. D.; Leopold, A. C.

    1985-01-01

    Living maize (Zea mays L.) coleoptile cells were observed using a horizontal microscope to determine the interaction between cytoplasmic streaming and gravity-induced amyloplast sedimentation. Sedimentation is heavily influenced by streaming which may (1) hasten or slow the velocity of amyloplast movement and (2) displace the plastid laterally or even upwards before or after sedimentation. Amyloplasts may move through transvacuolar strands or through the peripheral cytoplasm which may be divided into fine cytoplasmic strands of much smaller diameter than the plastids. The results indicate that streaming may contribute to the dynamics of graviperception by influencing amyloplast movement.

  11. Fuel-cell engine stream conditioning system

    DOEpatents

    DuBose, Ronald Arthur

    2002-01-01

    A stream conditioning system for a fuel cell gas management system or fuel cell engine. The stream conditioning system manages species potential in at least one fuel cell reactant stream. A species transfer device is located in the path of at least one reactant stream of a fuel cell's inlet or outlet, which transfer device conditions that stream to improve the efficiency of the fuel cell. The species transfer device incorporates an exchange media and a sorbent. The fuel cell gas management system can include a cathode loop with the stream conditioning system transferring latent and sensible heat from an exhaust stream to the cathode inlet stream of the fuel cell; an anode humidity retention system for maintaining the total enthalpy of the anode stream exiting the fuel cell related to the total enthalpy of the anode inlet stream; and a cooling water management system having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

  12. Stream isotherm shifts from climate change and implications for distributions of ectothermic organisms.

    PubMed

    Isaak, Daniel J; Rieman, Bruce E

    2013-03-01

    Stream ecosystems are especially vulnerable to climate warming because most aquatic organisms are ectothermic and live in dendritic networks that are easily fragmented. Many bioclimatic models predict significant range contractions in stream biotas, but subsequent biological assessments have rarely been done to determine the accuracy of these predictions. Assessments are difficult because model predictions are either untestable or so imprecise that definitive answers may not be obtained within timespans relevant for effective conservation. Here, we develop the equations for calculating isotherm shift rates (ISRs) in streams that can be used to represent historic or future warming scenarios and be calibrated to individual streams using local measurements of stream temperature and slope. A set of reference equations and formulas are provided for application to most streams. Example calculations for streams with lapse rates of 0.8C/100m and long-term warming rates of 0.1-0.2Cdecade(-1) indicate that isotherms shift upstream at 0.13-1.3kmdecade(-1) in steep streams (2-10% slope) and 1.3-25kmdecade(-1) in flat streams (0.1-1% slope). Used more generally with global scenarios, the equations predict isotherms shifted 1.5-43km in many streams during the 20th Century as air temperatures increased by 0.6C and would shift another 5-143km in the first half of the 21st Century if midrange projections of a 2C air temperature increase occur. Variability analysis suggests that short-term variation associated with interannual stream temperature changes will mask long-term isotherm shifts for several decades in most locations, so extended biological monitoring efforts are required to document anticipated distribution shifts. Resampling of historical sites could yield estimates of biological responses in the short term and should be prioritized to validate bioclimatic models and develop a better understanding about the effects of temperature increases on stream biotas. PMID:23504832

  13. Living with Spina Bifida

    MedlinePLUS

    ... Us Information For... Media Policy Makers Living With Spina Bifida Language: English Espaol (Spanish) Recommend on Facebook Tweet ... of the website provides information about living with spina bifida at different ages. Spina bifida affects the entire ...

  14. NIGMS's Living Labs

    MedlinePLUS

    ... Bar Home Current Issue Past Issues NIGMS's Living Labs Past Issues / Summer 2007 Table of Contents For ... Harmless roundworms found in soil now live in lab dishes, helping scientists discover fundamental mechanisms involved in ...

  15. Living with Hemophilia

    MedlinePLUS

    ... page from the NHLBI on Twitter. Living With Hemophilia If you or your child has hemophilia, you ... today is likely to live a normal lifespan. Hemophilia Treatment Centers The Federal Government funds a nationwide ...

  16. Living with Kidney Cancer

    MedlinePLUS

    ... Trials Find A Clinical Trial (EmergingMed) A Patient’s Perspective Live Living With Kidney Cancer Cancer Nutrition Information ( ... Second, many insurance companies have formal claims appeal processes. You can appeal your claim and have it ...

  17. Influenza Vaccine, Live Intranasal

    MedlinePLUS

    What is live, attenuated influenza vaccine-LAIV (nasal spray)?A dose of flu vaccine is recommended every flu season. Children younger ... needs only one dose each flu season. The live, attenuated influenza vaccine (called LAIV) may be given ...

  18. Living with Sarcoidosis

    MedlinePLUS

    ... page from the NHLBI on Twitter. Living With Sarcoidosis Sarcoidosis has no cure, but you can take ... Content: NEXT >> Featured Video Living With and Managing Sarcoidosis 05/18/2011 This video—presented by the ...

  19. Living with Cystic Fibrosis

    MedlinePLUS

    ... Topics » Cystic Fibrosis » Living With Cystic Fibrosis Explore Cystic Fibrosis What Is... Other Names Causes Who Is at Risk Signs & Symptoms Diagnosis Treatments Living With Clinical Trials Links Related Topics Bronchiectasis ...

  20. Streaming Compression of Hexahedral Meshes

    SciTech Connect

    Isenburg, M; Courbet, C

    2010-02-03

    We describe a method for streaming compression of hexahedral meshes. Given an interleaved stream of vertices and hexahedral our coder incrementally compresses the mesh in the presented order. Our coder is extremely memory efficient when the input stream documents when vertices are referenced for the last time (i.e. when it contains topological finalization tags). Our coder then continuously releases and reuses data structures that no longer contribute to compressing the remainder of the stream. This means in practice that our coder has only a small fraction of the whole mesh in memory at any time. We can therefore compress very large meshes - even meshes that do not file in memory. Compared to traditional, non-streaming approaches that load the entire mesh and globally reorder it during compression, our algorithm trades a less compact compressed representation for significant gains in speed, memory, and I/O efficiency. For example, on the 456k hexahedra 'blade' mesh, our coder is twice as fast and uses 88 times less memory (only 3.1 MB) with the compressed file increasing about 3% in size. We also present the first scheme for predictive compression of properties associated with hexahedral cells.

  1. Inactive comets within meteoroid streams

    NASA Astrophysics Data System (ADS)

    Kokhirova, Gulchekhra; Babadzhanov, Pulat; Obrubov, Yuri

    2015-08-01

    The modern concepts of formation and evolution of the meteoroid streams originated as a result of disintegration of cometary nuclei are presented. The action of planetary perturbations that defines the orbital evolution of meteoroids is discussed. The main regularities in variations of the orbital elements as well as of the heliocentric distances of ascending and descending nodes are found on the base of calculation of orbital evolution of a sample of NEAs. A dispersion of the orbits is increasing with a time and meteoroid streams in dependence of the type of a parent comet orbit can produce up to eight meteor showers observable at the Earth. It is recognized that some meteoroid streams contain large extinct fragments of cometary nuclei. These fragments have been found among NEAs and should be considered as the constituent parts of meteoroid streams. Consequently, meteoroid streams consist of both small particles and large fireball-producing bodies. This fact supported by the results of investigation of a sample of three asteroid-meteoroid complexes.

  2. Towards Clausal Discovery for Stream Mining

    NASA Astrophysics Data System (ADS)

    Dries, Anton; de Raedt, Luc

    With the increasing popularity of data streams it has become time to adapt logical and relational learning techniques for dealing with streams. In this note, we present our preliminary results on upgrading the clausal discovery paradigm towards the mining of streams. In this setting, there is a stream of interpretations and the goal is to learn a clausal theory that is satisfied by these interpretations. Furthermore, in data streams the interpretations can be read (and processed) only once.

  3. Living Willow Huts

    ERIC Educational Resources Information Center

    Keeler, Rusty

    2007-01-01

    Living Willow Huts are inexpensive to make, fun to plant, easy to grow, and make beautiful spaces for children. They involve planting dormant willow shoots in the ground and weaving them into shapes that will sprout and grow over time. People have been creating similar living architecture throughout the world for centuries in the forms of living

  4. Independent Living Course

    ERIC Educational Resources Information Center

    Tipping, Joyce

    1978-01-01

    Designed to help handicapped persons who have been living a sheltered existence develop independent living skills, this course is divided into two parts. The first part consists of a five-day apartment live-in experience, and the second concentrates on developing the learners' awareness of community resources and consumer skills. (BM)

  5. Perturbing Streaming in Dictyostelium Discoideum

    NASA Astrophysics Data System (ADS)

    McCann, Colin; Kriebel, Paul; Parent, Carole; Rericha, Erin; Losert, Wolfgang

    2007-03-01

    Upon starvation the social amoebae Dictyostelium discoideum aggregate to form multicellular organisms. During the transition from single cells to full aggregates, cells relay the chemotactic signal, align in a head-to-tail fashion, and follow each other in streams. To gain more insight into streaming behavior we investigated its robustness by perturbing the strength of the relayed chemoattractant. We measured the effects of plating the cells at varying densities, placing them in excess extracellular fluid thereby diluting cell-cell signals, or directly mixing up the local external fluid using ultrasound-induced bubble-driven flow. We compared wild type cells to cells devoid of signal relay and measured how streaming affects cell speed, directionality, and extent of directed migration. Results will be discussed and a model describing our findings will be presented.

  6. Streaming simplification of tetrahedral meshes.

    PubMed

    Vo, Huy T; Callahan, Steven P; Lindstrom, Peter; Pascucci, Valerio; Silva, Cludio T

    2007-01-01

    Unstructured tetrahedral meshes are commonly used in scientific computing to represent scalar, vector, and tensor fields in three dimensions. Visualization of these meshes can be difficult to perform interactively due to their size and complexity. By reducing the size of the data, we can accomplish real-time visualization necessary for scientific analysis. We propose a two-step approach for streaming simplification of large tetrahedral meshes. Our algorithm arranges the data on disk in a streaming, I/O-efficient format that allows coherent access to the tetrahedral cells. A quadric-based simplification is sequentially performed on small portions of the mesh in-core. Our output is a coherent streaming mesh which facilitates future processing. Our technique is fast, produces high quality approximations, and operates out-of-core to process meshes too large for main memory. PMID:17093343

  7. Dynamic visualization of data streams

    DOEpatents

    Wong, Pak Chung (Richalnd, WA); Foote, Harlan P. (Richland, WA); Adams, Daniel R. (Kennewick, WA); Cowley, Wendy E. (Richland, WA); Thomas, James J. (Richland, WA)

    2009-07-07

    One embodiment of the present invention includes a data communication subsystem to receive a data stream, and a data processing subsystem responsive to the data communication subsystem to generate a visualization output based on a group of data vectors corresponding to a first portion of the data stream. The processing subsystem is further responsive to a change in rate of receipt of the data to modify the visualization output with one or more other data vectors corresponding to a second portion of the data stream as a function of eigenspace defined with the group of data vectors. The system further includes a display device responsive to the visualization output to provide a corresponding visualization.

  8. Morphodynamics of supraglacial streams (Invited)

    NASA Astrophysics Data System (ADS)

    Karlstrom, L.; Manga, M.; Gajjar, P.

    2010-12-01

    Supraglacial hydrologic networks exhibit structure and morphodynamics reminiscent of alluvial channels, in an environment where the primary mechanism of erosion is thermal and timescales of topographic adjustment are days to weeks. Supraglacial stream incision is strongly modulated by solar forcing, at times faster or slower than the large-scale lowering of the glacial surface. This variability, in combination with control by structures within the ice or other surface topography, produces a time-evolving drainage network over the course of the melt season. Near the snow line, porous ice facilitates channel development and abandonment via seepage, whereas near the terminus channels are more stable and larger in scale. Discharge generally increases with drainage area, except in cases where water is lost through moulins or crevasses. We report here on fieldwork at the Mendenhall and Llewellyn glaciers on the Juneau Icefield, aimed at better characterizing flow and incision dynamics of supraglacial streams. Time series of temperature, velocity and isotopic composition reveal diurnal variability in flow processes, with clear discharge dependence. GPS profiles show slope dependence of stream sinuousity, and we observe differential incision of ice surface and streams along with downstream migration of meanders and of ice bedforms. We document drainage density, and identify subsurface water movement near the snow line that facilitates channelization. These field measurements are used to develop and validate a theoretical model of meander formation in supraglacial streams, based on the framework of bend theory in alluvial meanders (Karlstrom et al., in review). We find empirically that meandering in supraglacial streams globally follows the linear wavelength-width power law relation found in alluvial and bedrock rivers, but with a smaller intercept. Our linear theory can reproduce this relation, as well as the observed downstream migration of meanders.

  9. Temperature of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Gulf Stream is one of the strong ocean currents that carries warm water from the sunny tropics to higher latitudes. The current stretches from the Gulf of Mexico up the East Coast of the United States, departs from North America south of the Chesapeake Bay, and heads across the Atlantic to the British Isles. The water within the Gulf Stream moves at the stately pace of 4 miles per hour. Even though the current cools as the water travels thousands of miles, it remains strong enough to moderate the Northern European climate. The image above was derived from the infrared measurements of the Moderate-resolution Imaging Spectroradiometer (MODIS) on a nearly cloud-free day over the east coast of the United States. The coldest waters are shown as purple, with blue, green, yellow, and red representing progressively warmer water. Temperatures range from about 7 to 22 degrees Celsius. The core of the Gulf Stream is very apparent as the warmest water, dark red. It departs from the coast at Cape Hatteras, North Carolina. The cool, shelf water from the north entrains the warmer outflows from the Chesapeake and Delaware Bays. The north wall of the Gulf Stream reveals very complex structure associated with frontal instabilities that lead to exchanges between the Gulf Stream and inshore waters. Several clockwise-rotating warm core eddies are evident north of the core of the Gulf Stream, which enhance the exchange of heat and water between the coastal and deep ocean. Cold core eddies, which rotate counter clockwise, are seen south of the Gulf Stream. The one closest to Cape Hatteras is entraining very warm Gulf Stream waters on its northwest circumference. Near the coast, shallower waters have warmed due to solar heating, while the deeper waters offshore are markedly cooler (dark blue). MODIS made this observation on May 8, 2000, at 11:45 a.m. EDT. For more information, see the MODIS-Ocean web page. The sea surface temperature image was created at the University of Miami using the 11- and 12-micron bands, by Bob Evans, Peter Minnett, and co-workers.

  10. Riparian influences on stream fish assemblage structure in urbanizing streams

    USGS Publications Warehouse

    Roy, A.H.; Freeman, B.J.; Freeman, Mary C.

    2007-01-01

    We assessed the influence of land cover at multiple spatial extents on fish assemblage integrity, and the degree to which riparian forests can mitigate the negative effects of catchment urbanization on stream fish assemblages. Riparian cover (urban, forest, and agriculture) was determined within 30 m buffers at longitudinal distances of 200 m, 1 km, and the entire network upstream of 59 non-nested fish sampling locations. Catchment and riparian land cover within the upstream network were highly correlated, so we were unable to distinguish between those variables. Most fish assemblage variables were related to % forest and % urban land cover, with the strongest relations at the largest spatial extent of land cover (catchment), followed by riparian land cover in the 1-km and 200-m reach, respectively. For fish variables related to urban land cover in the catchment, we asked whether the influence of riparian land cover on fish assemblages was dependent on the amount of urban development in the catchment. Several fish assemblage metrics (endemic richness, endemic:cosmopolitan abundance, insectivorous cyprinid richness and abundance, and fluvial specialist richness) were all best predicted by single variable models with % urban land cover. However, endemic:cosmopolitan richness, cosmopolitan abundance, and lentic tolerant abundance were related to % forest cover in the 1-km stream reach, but only in streams that had <15% catchment urban land cover. In these cases, catchment urbanization overwhelmed the potential mitigating effects of riparian forests on stream fishes. Together, these results suggest that catchment land cover is an important driver of fish assemblages in urbanizing catchments, and riparian forests are important but not sufficient for protecting stream ecosystems from the impacts of high levels of urbanization.

  11. A secure transmission scheme of streaming media based on the encrypted control message

    NASA Astrophysics Data System (ADS)

    Li, Bing; Jin, Zhigang; Shu, Yantai; Yu, Li

    2007-09-01

    As the use of streaming media applications increased dramatically in recent years, streaming media security becomes an important presumption, protecting the privacy. This paper proposes a new encryption scheme in view of characteristics of streaming media and the disadvantage of the living method: encrypt the control message in the streaming media with the high security lever and permute and confuse the data which is non control message according to the corresponding control message. Here the so-called control message refers to the key data of the streaming media, including the streaming media header and the header of the video frame, and the seed key. We encrypt the control message using the public key encryption algorithm which can provide high security lever, such as RSA. At the same time we make use of the seed key to generate key stream, from which the permutation list P responding to GOP (group of picture) is derived. The plain text of the non-control message XORs the key stream and gets the middle cipher text. And then obtained one is permutated according to P. In contrast the decryption process is the inverse process of the above. We have set up a testbed for the above scheme and found our scheme is six to eight times faster than the conventional method. It can be applied not only between PCs but also between handheld devices.

  12. Video Streaming in Online Learning

    ERIC Educational Resources Information Center

    Hartsell, Taralynn; Yuen, Steve Chi-Yin

    2006-01-01

    The use of video in teaching and learning is a common practice in education today. As learning online becomes more of a common practice in education, streaming video and audio will play a bigger role in delivering course materials to online learners. This form of technology brings courses alive by allowing online learners to use their visual and

  13. Stream Profiles, An Environmental Investigation.

    ERIC Educational Resources Information Center

    National Wildlife Federation, Washington, DC.

    This environmental unit is one of a series designed for integration within an existing curriculum. The unit is self-contained and requires minimal teacher preparation. The philosophy of the units is based on an experience-oriented process that encourages self-paced independent student work. In this unit, students construct a stream profile based

  14. Oxygen Sag and Stream Purification.

    ERIC Educational Resources Information Center

    Neal, Larry; Herwig, Roy

    1978-01-01

    Presents a literature review of water quality related to oxygen sag and stream purification, covering publications of 1976-77. This review includes: (1) self-purification models; (2) oxygen demand; and (3) reaeration and oxygen transfer. A list of 60 references is also presented. (HM)

  15. Video Streaming in Online Learning

    ERIC Educational Resources Information Center

    Hartsell, Taralynn; Yuen, Steve Chi-Yin

    2006-01-01

    The use of video in teaching and learning is a common practice in education today. As learning online becomes more of a common practice in education, streaming video and audio will play a bigger role in delivering course materials to online learners. This form of technology brings courses alive by allowing online learners to use their visual and…

  16. Free-Stream-Capturing Metrics

    NASA Technical Reports Server (NTRS)

    Obayashi, Shigeru

    1993-01-01

    Report summarizes techniques for preservation of free-stream flows in finite-volume and finite-difference flow computations involving transformations between moving and stationary coordinates. Techniques necessary for accurate computations of complicated flows; such as, computing flow about helicopter rotor by use of grid conforming to and moving with rotor blades.

  17. ALIENS IN WESTERN STREAM ECOSYSTEMS

    EPA Science Inventory

    The USEPA's Environmental Monitoring and Assessment Program conducted a five year probability sample of permanent mapped streams in 12 western US states. The study design enables us to determine the extent of selected riparian invasive plants, alien aquatic vertebrates, and some ...

  18. POPULATION DECLINE IN STREAM FISH

    EPA Science Inventory

    Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

  19. NATIONAL STREAM SURVEY DATABASE GUIDE

    EPA Science Inventory

    The National Stream Survey (NSS), conducted in the spring of 1985 and 1986, is one component of the U.S Environmental Protection Agency's National Surface Water Survey. This effort is in support of the National Acid Precipitation Assessment Program. he NSS was a synoptic, spring ...

  20. Molten Rock Streaming into Water

    USGS Multimedia Gallery

    The molten rock streams through an opening in the melter into a large container of water below, where it instantly cools into glass. __________ The USGS has created man-made moon dirt, or regolith, to help NASA prepare for upcoming moon explorations. Four tons of the simulant is expected to be mad...

  1. Dynamical Modelling of Meteoroid Streams

    NASA Astrophysics Data System (ADS)

    Clark, David; Wiegert, P. A.

    2012-10-01

    Accurate simulations of meteoroid streams permit the prediction of stream interaction with Earth, and provide a measure of risk to Earth satellites and interplanetary spacecraft. Current cometary ejecta and meteoroid stream models have been somewhat successful in predicting some stream observations, but have required questionable assumptions and significant simplifications. Extending on the approach of Vaubaillon et al. (2005)1, we model dust ejection from the cometary nucleus, and generate sample particles representing bins of distinct dynamical evolution-regulating characteristics (size, density, direction, albedo). Ephemerides of the sample particles are integrated and recorded for later assignment of frequency based on model parameter changes. To assist in model analysis we are developing interactive software to permit the turning of knobs of model parameters, allowing for near-real-time 3D visualization of resulting stream structure. With this tool, we will revisit prior assumptions made, and will observe the impact of introducing non-uniform cometary surface attributes and temporal activity. The software uses a single model definition and implementation throughout model verification, sample particle bin generation and integration, and analysis. It supports the adjustment with feedback of both independent and independent model values, with the intent of providing an interface supporting multivariate analysis. Propagations of measurement uncertainties and model parameter precisions are tracked rigorously throughout. We maintain a separation of the model itself from the abstract concepts of model definition, parameter manipulation, and real-time analysis and visualization. Therefore we are able to quickly adapt to fundamental model changes. It is hoped the tool will also be of use in other solar system dynamics problems. 1 Vaubaillon, J.; Colas, F.; Jorda, L. (2005) A new method to predict meteor showers. I. Description of the model. Astronomy and Astrophysics, Volume 439, Issue 2, August IV 2005, pp.751-760.

  2. GLOBULAR CLUSTERS AND DARK SATELLITE GALAXIES THROUGH THE STREAM VELOCITY

    SciTech Connect

    Naoz, Smadar; Narayan, Ramesh

    2014-08-10

    The formation of purely baryonic globular clusters with no gravitationally bound dark matter is still a theoretical challenge. We show that these objects might form naturally whenever there is a relative stream velocity between baryons and dark matter. The stream velocity causes a phase shift between linear modes of baryonic and dark matter perturbations, which translates to a spatial offset between the two components when they collapse. For a 2? (3?) density fluctuation, baryonic clumps with masses in the range 10{sup 5}-2.5 10{sup 6}M {sub ?} (10{sup 5}-4 10{sup 6}M {sub ?}) collapse outside the virial radii of their counterpart dark matter halos. These objects could survive as long-lived, dark-matter-free objects and might conceivably become globular clusters. In addition, their dark matter counterparts, which were deprived of gas, might become dark satellite galaxies.

  3. Effects of Stream Channel Characteristics on Nitrate Delivery to Streams and In-Stream Denitrification Rates, Raccoon River, Iowa

    NASA Astrophysics Data System (ADS)

    Prestegaard, K. L.; O'Connell, M.

    2004-05-01

    Streams in agricultural areas often exhibit significant channel and sediment modifications; they are often incised and transport more fine sediment than non-agricultural streams. These channel characteristics can influence stream water quality by modifying surface-groundwater interactions. In the Raccoon River basin, channel incision increases the delivery of nitrate from the groundwater to the streams. The sandy in-stream sediments, however, serve as very effective sites for in-stream denitrification. Nitrate delivery and in-stream denitrification was examined in 3 subwatersheds of the Raccoon River. Stream morphology, water quality, and sediment characteristics were measured at 35 sites with varying land uses. Headwater stream nitrate concentration increased with percent row crops and the amount of channel incision. Downstream sites showed a wide variation in nitrate concentration with land use. Stream nitrate concentrations were measured at 6 sites in each of 3 streams with high percentages of row crop land uses during high summer baseflow following the 1993 floods and during average summer baseflow in 1995. Nitrate concentrations were systematically higher for the high baseflow conditions of 1993 than the average year (1995). This change in nitrate concentration is interpreted as the increased effectiveness of nitrate delivery to the stream during periods of high water tables. The effect was most pronounced in incised reaches. All 3 streams show downstream decreases in nitrate concentration. Water samples for all the sites in the watersheds were analyzed for nitrogen isotopic composition. The nitrogen isotopic composition shifts with towards higher d 15N values with decreasing nitrate concentration. This is consistent with denitrification reactions that selectively remove the 14N leaving a higher proportion of 15N in the nitrate. This suggests that most of the downstream decrease in nitrate concentrations is a result of in-stream denitrification. The high rates of in-stream denitrification might be a consequence of thick, sandy, carbon-rich stream sediments, which are themselves a consequence of agricultural erosion and deposition.

  4. Discounting human lives

    SciTech Connect

    Cropper, M.L. ); Portney, P.R.

    1992-09-01

    The future costs of regulatory programs to protect human health are routinely discounted, but the lives they save in the future are not. To shed light on the public's attitude toward the discounting of human lives, researchers at Resources for the Future asked 2,600 individuals to choose between one hypothetical program that would save lives immediately and another that would save lives in 5, 10, 25, 50, or 100 years. From the responses, they inferred the number of lives that must be saved in the future to make people as content as saving one life today, compared this implicit discount rate to the respondents' discount rate for money, and identified several factors that affect discount rates for human lives.

  5. Strategies for managing the effects of urban development on streams

    USGS Publications Warehouse

    Cappiella, Karen; Stack, William P.; Fraley-McNeal, Lisa; Lane, Cecilia; McMahon, Gerard

    2012-01-01

    Urban development remains an important agent of environmental change in the United States. The U.S. population grew by 17 percent from 1982 to 1997, while urbanized land area grew by 47 percent, suggesting that urban land consumption far outpaced population growth (Fulton and others, 2001; Sierra Club, 2003; American Farmland Trust, 2009). Eighty percent of Americans now live in metropolitan areas. Each American effectively occupies about 20 percent more developed land (for housing, schools, shopping, roads, and other related services) than 20 years ago (Markham and Steinzor, 2006). Passel and Cohn (2008) predict a dramatic 48 percent increase in the population of the United States from 2005 to 2050. The advantages and challenges of living in these developed areasconvenience, congestion, employment, pollutionare part of the day-to-day realities of most Americans. Nowhere are the environmental changes associated with urban development more evident than in urban streams. The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program investigation of the effects of urban development on stream ecosystems (EUSE) during 19992004 provides the most spatially comprehensive analysis of stream impacts of urban development that has been completed in the United States. A nationally consistent study design was used in nine metropolitan areas of the United StatesPortland, Oregon; Salt Lake City, Utah; Birmingham, Alabama; Atlanta, Georgia; Raleigh, North Carolina; Boston, Massachusetts; Denver, Colorado; Dallas, Texas; and Milwaukee, Wisconsin. A summary report published as part of the EUSE study describes several of these impacts on urban streams (Coles and others, 2012).

  6. Stream Tables and Watershed Geomorphology Education.

    ERIC Educational Resources Information Center

    Lillquist, Karl D.; Kinner, Patricia W.

    2002-01-01

    Reviews copious stream tables and provides a watershed approach to stream table exercises. Results suggest that this approach to learning the concepts of fluvial geomorphology is effective. (Contains 39 references.) (DDR)

  7. Cryosphere: Order in Antarctic ice streams

    NASA Astrophysics Data System (ADS)

    Sergienko, O. V.

    2015-11-01

    Ice streams transport ice rapidly from the interior of the Antarctic ice sheet to the coast. An analysis of surface flow convergence suggests that ice flow and geometry are intricately linked within these ice streams.

  8. Stream Channelization: Conflict Between Ditchers, Conservationists

    ERIC Educational Resources Information Center

    Gillette, Robert

    1972-01-01

    Summarizes the argument between the advocates of stream straightening for flood control, drainage, and navigation, and those concerned with the maintenance of ecological communities and the aesthetic values of natural" streams. (AL)

  9. Stream Gauges and Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Alsdorf, D. E.

    2010-12-01

    Satellite measurements should not be viewed as a replacement for stream gauges. However, occasionally it is suggested that because satellite-based measurements can provide river discharge, a motivation for satellite approaches is an increasing lack of stream gauges. This is an argument for more stream gauges, but not necessarily for satellite measurements. Rather, in-situ and spaceborne methods of estimating discharge are complementary. Stream gauges provide frequent measurements at one point in the river reach whereas satellites have the potential to measure throughout all reaches but at orbital repeat intervals of days to weeks. The Surface Water and Ocean Topography satellite mission (SWOT) is an opportunity to further develop these complements. The motivation for SWOT, and indeed for any satellite based method of estimating discharge, should not be as a replacement for stream gauges. Scientific and application uses should motivate the measurements. For example, understanding floods with their dynamic water surfaces are best sampled from remote platforms that provide water surface elevations throughout the floodwave. As another example, todays water and energy balance models are giving outputs at increasing spatial resolution and are making use of water surface elevations throughout the modeled basin. These models require a similar resolution in the calibrating and validating observations. We should also be aware of practical limitations. In addition to providing spatially distributed hydrodynamic measurements on rivers, SWOT will be able to measure storage changes in the estimated 30 million lakes in the world that are larger than a hectare. Knowing the storage changes in these lakes is especially important in certain regions such as the Arctic but gauging even a small fraction of these is impractical. Another motivator for satellite methods is that even in the presence of stream gauges, discharge data is not always well shared throughout all countries within an international river basin (this is also an argument for better diplomacy). Essentially, where gauges exist, satellite measurements allow the spatial extension of in-situ observations, especially when jointly combined in models such as data assimilation methods. The opportunity for new hydrologic science and discovery is enhanced when the strengths of traditional and new measurements are combined.

  10. Time of travel of selected Arkansas streams

    USGS Publications Warehouse

    Lamb, T.E.

    1982-01-01

    Between 1971 and 1981, time-of-travel and dispersion measurements were made in 15 streams in Arkansas. Most of the streams studied were at or near base flow. Graphs are presented for predicting traveltime of solutes in segments of the streams studied. The relationship of time of passage and peak unit concentration to traveltime is presented for two of the streams. Examples of use and application of the data are given. (USGS)

  11. Maximizing Resource Utilization in Video Streaming Systems

    ERIC Educational Resources Information Center

    Alsmirat, Mohammad Abdullah

    2013-01-01

    Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to…

  12. Maximizing Resource Utilization in Video Streaming Systems

    ERIC Educational Resources Information Center

    Alsmirat, Mohammad Abdullah

    2013-01-01

    Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to

  13. Hydrology of Channelized and Natural Headwater Streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding hydrology is paramount for optimal ecologic function and management of headwater streams. The objective of this study was to characterize and compare headwater streams within the Upper Big Walnut Creek watershed in Ohio. Two channelized and two unchannelized streams were instrumented w...

  14. The Stream Table in Physical Geography Instruction.

    ERIC Educational Resources Information Center

    Wikle, Thomas A.; Lightfoot, Dale R.

    1997-01-01

    Outlines a number of activities to be conducted with a stream table (large wooden box filled with sediment and designed for water to pass through) in class. Activities illustrate such fluvial processes as stream meandering, erosion, transportation, and deposition. Includes a diagram for constructing a stream table. (MJP)

  15. Olefin Recovery from Chemical Industry Waste Streams

    SciTech Connect

    A.R. Da Costa; R. Daniels; A. Jariwala; Z. He; A. Morisato; I. Pinnau; J.G. Wijmans

    2003-11-21

    The objective of this project was to develop a membrane process to separate olefins from paraffins in waste gas streams as an alternative to flaring or distillation. Flaring these streams wastes their chemical feedstock value; distillation is energy and capital cost intensive, particularly for small waste streams.

  16. Dynamical Properties of Collisionless Star Streams

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.

    2015-02-01

    A sufficiently extended satellite in the tidal field of a host galaxy loses mass to create nearly symmetric leading and trailing tidal streams. We study the case in which tidal heating drives mass loss from a low mass satellite. The stream effectively has two dynamical components, a common angular momentum core superposed with episodic pulses with a broader angular momentum distribution. The pulses appear as spurs on the stream, oscillating above and below the stream centerline, stretching and blurring in configuration space as they move away from the cluster. Low orbital eccentricity streams are smoother and have less differential motion than high eccentricity streams. The tail of a high eccentricity stream can develop a fan of particles that wraps around at apocenter in a shell feature. We show that scaling the essentially stationary action-angle variables with the cube root of the satellite mass allows a low mass satellite stream to accurately predict the features in the stream from a satellite a thousand times more massive. As a practical astrophysical application, we demonstrate that narrow gaps in a moderate eccentricity stream, such as GD-1, blur out to 50% contrast over approximately six radial periods. A high eccentricity stream, such as Pal 5, will blur small gaps in only two radial orbits as can be understood from the much larger dispersion of angular momentum in the stream.

  17. Meteor streams in the making

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1977-01-01

    The well-known associations of meteor streams with periodic comets and the probable cometary origin of the zodiacal dust cloud point to the importance, in the cometary debris, of particles with masses exceeding roughly 10 to the -6th gram. It is shown that these large particles dominate in the sunward-oriented anomalous tails of comets. Their study is essential for meaningful estimates of the mass of meteor streams and of the injection rate of the cometary debris that contributes to the zodiacal cloud. Favorable conditions for the detection of anomalous tails can be recognized in advance, as demonstrated by the successful predictions for comets Kohoutek (1973 XII) and Bradfield (1975p). To answer the question as to whether short-period comets can support the zodiacal cloud, a study of anomalous tails at future returns of these comets is considered indispensable.

  18. Streaming visualization for collaborative environments.

    SciTech Connect

    Hereld, M.; Olson, E.; Papka, M. E.; Uram, T. D.

    2008-01-01

    Connecting expensive and scarce visual data analysis resources to end-users is a major challenge today. We describe a flexible mechanism for meeting this challenge based on commodity compression technologies for streaming video. The advantages of this approach include simplified application development, access to generic client components for viewing, and simplified incorporation of improved codecs as they become available. In this paper we report newly acquired experimental results for two different applications being developed to exploit this approach and test its merits. One is based on a new plugin for ParaView that adds video streaming cleanly and transparently to existing applications. The other is a custom volume rendering application with new remote capabilities. Using typical datasets under realistic conditions, we find the performance for both is satisfactory.

  19. Metamers of the ventral stream

    PubMed Central

    Freeman, Jeremy; Simoncelli, Eero P.

    2011-01-01

    The human capacity to recognize complex visual patterns emerges in a sequence of brain areas known as the ventral stream, beginning with primary visual cortex (V1). We develop a population model for mid-ventral processing, in which non-linear combinations of V1 responses are averaged within receptive fields that grow with eccentricity. To test the model, we generate novel forms of visual metamers — stimuli that differ physically, but look the same. We develop a behavioral protocol that uses metameric stimuli to estimate the receptive field sizes in which the model features are represented. Because receptive field sizes change along the ventral stream, the behavioral results can identify the visual area corresponding to the representation. Measurements in human observers implicate V2, providing a new functional account of this area. The model explains deficits of peripheral vision known as “crowding”, and provides a quantitative framework for assessing the capabilities of everyday vision. PMID:21841776

  20. Energy separation in fluid streams

    NASA Astrophysics Data System (ADS)

    Eckert, E. R. G.

    1986-04-01

    The physical processes underlying energy separation in gases and liquids are examined with particular reference to the processes occurring in the vortex and resonance tubes. It is shown that, in the vortex tube, energy separation is primarily caused by pressure forces acting on the fluctuating curved streamlines with a minor contribution from viscous forces. The effectiveness of energy separation in the vortex tube decreases as the mass flow ratio moves toward zero or one. The vortex tube is found to be the most effective device of those considered here when a stream of cool air or cold gas has to be obtained. The resonance tube, however, is more effective in generating a gas stream of high temperature.

  1. Streaming visualization for collaborative environments

    NASA Astrophysics Data System (ADS)

    Hereld, M.; Olson, E.; Papka, M. E.; Uram, T. D.

    2008-07-01

    Connecting expensive and scarce visual data analysis resources to end-users is a major challenge today. We describe a flexible mechanism for meeting this challenge based on commodity compression technologies for streaming video. The advantages of this approach include simplified application development, access to generic client components for viewing, and simplified incorporation of improved codecs as they become available. In this paper we report newly acquired experimental results for two different applications being developed to exploit this approach and test its merits. One is based on a new plugin for ParaView that adds video streaming cleanly and transparently to existing applications. The other is a custom volume rendering application with new remote capabilities. Using typical datasets under realistic conditions, we find the performance for both is satisfactory.

  2. Living Willow Huts

    ERIC Educational Resources Information Center

    Keeler, Rusty

    2007-01-01

    Living Willow Huts are inexpensive to make, fun to plant, easy to grow, and make beautiful spaces for children. They involve planting dormant willow shoots in the ground and weaving them into shapes that will sprout and grow over time. People have been creating similar living architecture throughout the world for centuries in the forms of living…

  3. Is It Living?

    ERIC Educational Resources Information Center

    Keeley, Page

    2011-01-01

    The word "living" is commonly used throughout elementary science lessons that focus on the biological world. It is a word teachers often take for granted when teaching life science concepts. How similar the constructed meaning of a common word like "living" is to the meaning intended by the teacher or instructional materials depends on how a

  4. Acoustic streaming in superfluid helium

    SciTech Connect

    Rooney, J.A.; Smith, C.W.; Carey, R.F.

    1982-07-01

    Quantitative measurements of acoustic streaming velocity in liquid helium as a function of sound intensity (up to the cavitation threshold), frequency (1, 3, and 10 MHz), and temperature (1.43 K< or =T< or =2.19 K) are reported. A transition to superfluid turbulence, several flow regions and flow fluctuations are observed. Comparison with the predictions of the second-order Khalatnikov two- fluid hydrodynamic equations indicates good functional and quantitative agreement.

  5. Where the Hippopotamus Lives.

    ERIC Educational Resources Information Center

    Richard, Don

    1983-01-01

    During their environmental education year, 12-year-old students from Treverton Preparatory School (Natal, South Africa) learn all subjects in an environmental manner. The central theme streaming through the internationally recognized program is the Mooi River. A three-day camping trip and other outdoor activities are included. (MH)

  6. Academic Self-Concepts in Ability Streams: Considering Domain Specificity and Same-Stream Peers

    ERIC Educational Resources Information Center

    Liem, Gregory Arief D.; McInerney, Dennis M.; Yeung, Alexander S.

    2015-01-01

    The study examined the relations between academic achievement and self-concepts in a sample of 1,067 seventh-grade students from 3 core ability streams in Singapore secondary education. Although between-stream differences in achievement were large, between-stream differences in academic self-concepts were negligible. Within each stream, levels of…

  7. Academic Self-Concepts in Ability Streams: Considering Domain Specificity and Same-Stream Peers

    ERIC Educational Resources Information Center

    Liem, Gregory Arief D.; McInerney, Dennis M.; Yeung, Alexander S.

    2015-01-01

    The study examined the relations between academic achievement and self-concepts in a sample of 1,067 seventh-grade students from 3 core ability streams in Singapore secondary education. Although between-stream differences in achievement were large, between-stream differences in academic self-concepts were negligible. Within each stream, levels of

  8. Where Did All the Streams Go? Effects of Urbanization on Hydrologic Permanence of Headwater Streams

    EPA Science Inventory

    Headwater streams represent a majority (up to 70%) of the stream length in the United States; however, these small streams are often piped or filled to accommodate residential, commercial, and industrial development. Legal protection of headwater streams under the Clean Water Ac...

  9. Southern Hemisphere meteor stream determinations

    NASA Technical Reports Server (NTRS)

    Gartrell, G.; Elford, W. G.

    1975-01-01

    Meteor orbits have been deduced from radio observations of meteor trails carried out at Adelaide, Australia, using a combined multistation CW and pulse radar system operating at 27 MHz. The orbits of 1667 meteors have been determined down to a limiting radio magnitude of +8. The data have been systematically searched for stream meteors, and the significance of minor associations has been appraised. Altogether, 40.4% of the orbits were found to be associated with at least one other orbit, and 29.8% with two or more. Numerous minor streams with high inclination and low eccentricity have been found at deep southern declinations from December to March, with little activity in this quarter during June and October. In addition to confirming several previously established cometary associations, a comprehensive search has indicated that 34 of the meteor associations may be related to 17 comets. Associations between several long-period comets and low-eccentricity high-inclination streams appear to be indisputable, and they confirm the origin of at least some of the 'toroidal group' meteors.

  10. Interplanetary stream magnetism - Kinematic effects

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Barouch, E.

    1976-01-01

    The particle density and the magnetic-field intensity and direction are calculated for volume elements of the solar wind as a function of the initial magnetic-field direction and the initial speed gradient. It is assumed that the velocity is constant and radial. These assumptions are approximately valid between about 0.1 and 1.0 AU for many streams. Time profiles of the particle density, field intensity, and velocity are calculated for corotating streams, neglecting effects of pressure gradients. The compression and rarefaction of the magnetic field depend sensitively on the initial field direction. By averaging over a typical stream, it is found that the average radial field intensity is inversely proportional to the square of the heliocentric distance, whereas the average intensity in the direction of the planets' motion does not vary in a simple way, consistent with deep space observations. Changes of field direction may be very large, depending on the initial angle; but when the initial angle at 0.1 AU is such that the base of the field line corotates with the sun, the spiral angle is the preferred direction at 1 AU. The theory is also applicable to nonstationary flows.

  11. Streaming video for distributed simulation

    NASA Astrophysics Data System (ADS)

    Webster, Steven G.; Paul, Douglas J.

    2010-04-01

    Distributed simulation environments are increasingly using video to stimulate operational systems and their prototypical equivalents. Traditionally, this video has been synthesized and delivered by an analog means to consuming software applications. Scene generators typically render to commodity video cards, generate out of band metadata, and convert their outputs to formats compatible with the stimulated systems. However, the approach becomes hardware intensive as environment scale and distribution requirements grow. Streaming video technologies can be applied to uncouple video sources from their consumers, thereby enabling video channel quantities beyond rendering hardware outputs. Moreover, metadata describing the video content can be multiplexed, thereby ensuring temporal registration between video and its attribution. As an application of this approach, the Night Vision Image Generator (NVIG) has been extended and integrated with distribution architectures to deliver streaming video in virtual simulation environments. Video capture hardware emulation and application frame buffer reads are considered for capturing rendered scenes. Video source to encoder bindings and content multiplexing are realized by combining third party video codec, container, and transport implementations with original metadata encoders. Readily available commercial and open source solutions are utilized for content distribution and demultiplexing to a variety of formats and clients. Connected and connectionless distribution approaches are discussed with respect to latency and reliability. Client side scalability, latency, and initialization issues are addressed. Finally, the solution is applied to tactical systems stimulus and training, showing the evolvement from the analog to the streamed video approach.

  12. Impacts of biological diversity on sediment transport in streams

    NASA Astrophysics Data System (ADS)

    Albertson, L. K.; Cardinale, B. J.; Sklar, L. S.

    2012-12-01

    Over the past decade, an increasing number of studies have shown that biological structures (e.g. plant roots) have large impacts on sediment transport, and that physical models that do not incorporate these biological impacts can produce qualitatively incorrect predictions. But while it is now recognized that biological structures influence sediment transport, work to date has focused primarily on the impacts of individual, usually dominant, species. Here, we ask whether competitive interactions cause multi-species communities to have fundamentally different impacts on sediment mobility than single-species systems. We use a model system with caddisfly larvae, which are insects that live in the benthic habitat of streams where they construct silken catchnets across pore spaces between rocks to filter food particles. Because caddisflies can reach densities of 1,000s per m2 with each larva spinning hundreds of silken threads between rocks, studies have shown that caddisflies reduce the probability of bed movement during high discharge events. To test whether streams with multiple species of caddisfly are stabilized any differently than single-species streams, we manipulated the presence or absence of two common species (Ceratopsyche oslari, Arctopsyche californica) in substrate patches (0.15 m2) in experimental stream channels (50-m long x 1-m wide) with fully controlled hydrology at the Sierra Nevada Aquatic Research Laboratory. This experiment was designed to extend the scale of previous laboratory mesocosm studies, which showed that critical shear stress is 31% higher in a multi-species flume mesocosm compared to a single-species mesocosm. Under these more realistic field conditions, we found that critical shear stress was, on average, 30% higher in streams with caddisflies vs. controls with no caddisflies. However, no differences were detected between treatments with 2 vs. 1 species. We hypothesize that the minimal effect of diversity on critical shear stress resulted because intense competitive interactions (fighting, biting, etc.) caused the caddisflies to drift downstream and distribute longitudinally instead of vertically within the sediments, as we had previously observed in the mesocosm study. Taken together with previous results, our findings show that species interactions in multi-species communities can generate synergies that have fundamentally unique impacts on sediment stability compared to just single species communities, but these impacts will be scale dependent and vary with ecosystem complexity. Field tests are the next step to improve our ability to accurately quantify the influence of stream insects on sediment transport conditions, and the results reported here will help refine experimental design for tests in natural streams.

  13. Effect of land use on the composition, diversity and abundance of insects drifting in neotropical streams.

    PubMed

    Gimenez, B C G; Lansac-Tôha, F A; Higuti, J

    2015-11-01

    Streams may exhibit differences in community structure of invertebrate drift, which may be a reflex of variation in environmental factors, able to change in conditions of anthropogenic interventions. The aim of this study was to analyze the composition, diversity and abundance of insects drifting in two neotropical streams under different land use and to identify the environmental factors involved in determining such patterns. 54 taxa of aquatic insects were identified in urban and rural streams. The results indicated significant differences in species composition due to the replacement of specialist species by generalist species in the urban stream. Higher diversity of taxa was recorded in the rural stream, with high levels of dissolved oxygen and high water flow, which favored the occurrence of sensitive groups to environmental disturbances, such as Ephemeroptera, Plecoptera, Trichoptera and Coleoptera taxa, that living mainly in clean and well oxygenated waters. On the other hand, a higher density of insects drifting, especially Chironomidae, was observed in the urban stream, where high values of pH, electrical conductivity and nitrogen were observed. These larvae are able to explore a wide range of environmental conditions, owing to their great capacity for physiological adaptation. Despite observing the expected patterns, there were no significant differences between streams for the diversity and abundance of species. Thus, the species composition can be considered as the best predictor of impacts on the drifting insect community. PMID:26602342

  14. Flow effects on benthic stream invertebrates and ecological processes

    NASA Astrophysics Data System (ADS)

    Koprivsek, Maja; Brilly, Mitja

    2010-05-01

    Flow is the main abiotic factor in the streams. Flow affects the organisms in many direct and indirect ways. The organisms are directly affected by various hydrodynamic forces and mass transfer processes like drag forces, drift, shear stress, food and gases supply and washing metabolites away. Indirect effects on the organisms are determining and distribution of the particle size and structure of the substrate and determining the morphology of riverbeds. Flow does not affect only on individual organism, but also on many ecological effects. To expose just the most important: dispersal of the organisms, habitat use, resource acquisition, competition and predator-prey interactions. Stream invertebrates are adapted to the various flow conditions in many kinds of way. Some of them are avoiding the high flow with living in a hyporeic zone, while the others are adapted to flow with physical adaptations (the way of feeding, respiration, osmoregulation and resistance to draught), morphological adaptations (dorsoventrally flattened shape of organism, streamlined shape of organism, heterogeneous suckers, silk, claws, swimming hair, bristles and ballast gravel) or with behaviour. As the flow characteristics in a particular stream vary over a broad range of space and time scales, it is necessary to measure accurately the velocity in places where the organisms are present to determine the actual impact of flow on aquatic organisms. By measuring the mean flow at individual vertical in a single cross-section, we cannot get any information about the velocity situation close to the bottom of the riverbed where the stream invertebrates are living. Just measuring the velocity near the bottom is a major problem, as technologies for measuring the velocity and flow of natural watercourses is not adapted to measure so close to the bottom. New researches in the last two decades has shown that the thickness of laminar border layer of stones in the stream is only a few 100 micrometers, what is not enough to make a shelter for stream invertebrates. It serves as a shelter only for microorganisms, but the stream invertebrates have to avoid the swift flow or adapt to flow with adaptations described above. To understand what conditions are subject to aquatic organisms and how to adapt, it is essential. Both, knowledge of fluid dynamics in natural watercourses and ecology are needed to understand to what conditions the stream invertebrates are exposed and how they cope with them. Some investigations of near bed flow will be performed on the Glinica stream. The acoustic Doppler velocimeter SonTek will be adapted to measure so close to the bed as possible. It is expected we should be able to measure the velocities just 0,5 cm above the bed surface. We intend to measure the velocities on a natural and on a regulated reach and then compare the results.

  15. Evidence of Fanning in the Ophiuchus Stream

    NASA Astrophysics Data System (ADS)

    Sesar, Branimir; Price-Whelan, Adrian M.; Cohen, Judith G.; Rix, Hans-Walter; Pearson, Sarah; Johnston, Kathryn V.; Bernard, Edouard J.; Ferguson, Annette M. N.; Martin, Nicolas F.; Slater, Colin T.; Chambers, Kenneth C.; Flewelling, Heather; Wainscoat, Richard J.; Waters, Christopher

    2016-01-01

    The Ophiuchus stellar stream presents a dynamical puzzle: its old stellar populations (˜12 Gyr) cannot be reconciled with (1) its orbit in a simple model for the Milky Way potential and (2) its short angular extent, both of which imply that the observed stream formed within the last < 1 {{Gyr}}. Recent theoretical work has shown that streams on chaotic orbits may abruptly fan out near their apparent ends; stars in these fans are dispersed in both position and velocity and may be difficult to associate with the stream. Here we present the first evidence of such stream-fanning in the Ophiuchus stream, traced by four blue horizontal branch stars beyond the apparent end of the stream. These stars stand out from the background by their high velocities ({v}{{los}}> 230 km s-1) against ˜40 other stars: their velocities are comparable to those of the stream, but would be exceptional if they were unrelated halo stars. Their positions and velocities are, however, inconsistent with simple extrapolation of the observed cold, high-density portion of the stream. These observations suggest that stream-fanning may be a real, observable effect and, therefore, that Ophiuchus may be on a chaotic orbit. They also show that the Ophiuchus stream is more extended and hence dynamically older than previously thought, easing the stellar population versus dynamical age tension.

  16. Mechanisms for stream corridor protection. Final report

    SciTech Connect

    White, D.C.; Penosky, M.; Braden, J.B.; Mariner, R.D.; Dreher, D.

    1989-08-01

    This report assesses the protection currently provided to stream corridors in Illinois and makes recommendations for improving that protection. In addition to a comprehensive survey of current state and federal activities, the study surveyed selected states in order to identify program or policy alternatives applicable to stream protection in Illinois. These areas included the development of stream classification systems, the involvement of local interests, planning for greenway or stream corridor systems, and educational activities which teach the ecology of streams to the public. These programs offer ideas and suggestions for the state of Illinois to follow in protecting its stream resources. Although Illinois presently has no policy that recognizes the singular values of stream corridors, many of the state activities surveyed took place within the context of a state protection policy.

  17. Engineering living functional materials.

    PubMed

    Chen, Allen Y; Zhong, Chao; Lu, Timothy K

    2015-01-16

    Natural materials, such as bone, integrate living cells composed of organic molecules together with inorganic components. This enables combinations of functionalities, such as mechanical strength and the ability to regenerate and remodel, which are not present in existing synthetic materials. Taking a cue from nature, we propose that engineered 'living functional materials' and 'living materials synthesis platforms' that incorporate both living systems and inorganic components could transform the performance and the manufacturing of materials. As a proof-of-concept, we recently demonstrated that synthetic gene circuits in Escherichia coli enabled biofilms to be both a functional material in its own right and a materials-synthesis platform. To demonstrate the former, we engineered E. coli biofilms into a chemical-inducer-responsive electrical switch. To demonstrate the latter, we engineered E. coli biofilms to dynamically organize biotic-abiotic materials across multiple length scales, template gold nanorods, gold nanowires, and metal/semiconductor heterostructures, and synthesize semiconductor nanoparticles (Chen, A. Y. et al. (2014) Synthesis and patterning of tunable multiscale materials with engineered cells. Nat. Mater. 13, 515-523.). Thus, tools from synthetic biology, such as those for artificial gene regulation, can be used to engineer the spatiotemporal characteristics of living systems and to interface living systems with inorganic materials. Such hybrids can possess novel properties enabled by living cells while retaining desirable functionalities of inorganic systems. These systems, as living functional materials and as living materials foundries, would provide a radically different paradigm of materials performance and synthesis-materials possessing multifunctional, self-healing, adaptable, and evolvable properties that are created and organized in a distributed, bottom-up, autonomously assembled, and environmentally sustainable manner. PMID:25592034

  18. Engineering Living Functional Materials

    PubMed Central

    2016-01-01

    Natural materials, such as bone, integrate living cells composed of organic molecules together with inorganic components. This enables combinations of functionalities, such as mechanical strength and the ability to regenerate and remodel, which are not present in existing synthetic materials. Taking a cue from nature, we propose that engineered living functional materials and living materials synthesis platforms that incorporate both living systems and inorganic components could transform the performance and the manufacturing of materials. As a proof-of-concept, we recently demonstrated that synthetic gene circuits in Escherichia coli enabled biofilms to be both a functional material in its own right and a materials-synthesis platform. To demonstrate the former, we engineered E. coli biofilms into a chemical-inducer-responsive electrical switch. To demonstrate the latter, we engineered E. coli biofilms to dynamically organize biotic-abiotic materials across multiple length scales, template gold nanorods, gold nanowires, and metal/semiconductor heterostructures, and synthesize semiconductor nanoparticles (Chen, A. Y. et al. (2014) Synthesis and patterning of tunable multiscale materials with engineered cells. Nat. Mater.13, 515523.). Thus, tools from synthetic biology, such as those for artificial gene regulation, can be used to engineer the spatiotemporal characteristics of living systems and to interface living systems with inorganic materials. Such hybrids can possess novel properties enabled by living cells while retaining desirable functionalities of inorganic systems. These systems, as living functional materials and as living materials foundries, would provide a radically different paradigm of materials performance and synthesismaterials possessing multifunctional, self-healing, adaptable, and evolvable properties that are created and organized in a distributed, bottom-up, autonomously assembled, and environmentally sustainable manner. PMID:25592034

  19. Electrochemical/Pyrometallurgical Waste Stream Processing and Waste Form Fabrication

    SciTech Connect

    Steven Frank; Hwan Seo Park; Yung Zun Cho; William Ebert; Brian Riley

    2015-07-01

    This report summarizes treatment and waste form options being evaluated for waste streams resulting from the electrochemical/pyrometallurgical (pyro ) processing of used oxide nuclear fuel. The technologies that are described are South Korean (Republic of Korea – ROK) and United States of America (US) ‘centric’ in the approach to treating pyroprocessing wastes and are based on the decade long collaborations between US and ROK researchers. Some of the general and advanced technologies described in this report will be demonstrated during the Integrated Recycle Test (IRT) to be conducted as a part of the Joint Fuel Cycle Study (JFCS) collaboration between US Department of Energy (DOE) and ROK national laboratories. The JFCS means to specifically address and evaluated the technological, economic, and safe guard issues associated with the treatment of used nuclear fuel by pyroprocessing. The IRT will involve the processing of commercial, used oxide fuel to recover uranium and transuranics. The recovered transuranics will then be fabricated into metallic fuel and irradiated to transmutate, or burn the transuranic elements to shorter lived radionuclides. In addition, the various process streams will be evaluated and tested for fission product removal, electrolytic salt recycle, minimization of actinide loss to waste streams and waste form fabrication and characterization. This report specifically addresses the production and testing of those waste forms to demonstrate their compatibility with treatment options and suitability for disposal.

  20. Small mammal populations in a restored stream corridor

    SciTech Connect

    Wike, L.D.

    2000-03-13

    An opportunity to study the response of a small mammal community to restoration of a riparian wetland was provided by the Pen Branch project at the Savannah River Site (SRS). Live trapping of small mammals was conducted on six transects at Pen Branch in 1996 and 1998 and at three transects at Meyer's Branch, an unimpacted stream at SRS, in 1997 and 1998. Distributions of rates of capture of the four most common species were both spatially and temporally uneven. Kruskal-Wallis one-way analysis of variance found no significant differences in the relationship of capture rates between species and between treatment and both the within-stream control and Meyers Branch. Habitat use and movement within stream corridors appears to be dependent primarily on species, with age and sex perhaps contributing to preference and distance moved. The lack of differences in capture rates related to transect or treatment may be due to the close proximity of sample transects relative to the movement potential of the species sampled.

  1. Living with Heart Block

    MedlinePLUS

    ... ongoing care for your condition. Living With a Pacemaker People who have third-degree heart block and ... people who have second-degree heart block need pacemakers. These devices use electrical pulses to prompt the ...

  2. Adults Living with OI

    MedlinePLUS

    ... Contact Us | Login OIF Resources Especially For Parents Adults Youth Medical Professionals Media About OI Information & Support Research & Studies Donate How to Help The ... Adults Living with OI Write to us with your ...

  3. Living with Anemia

    MedlinePLUS

    ... page from the NHLBI on Twitter. Living With Anemia Often, you can treat and control anemia. If ... by an inherited or chronic disease or trauma. Anemia and Children/Teens Infants and young children have ...

  4. The Living Cosmos

    NASA Astrophysics Data System (ADS)

    Impey, Chris

    2011-06-01

    Preface; 1. The unfinished revolution; 2. Life's origins; 3. Extreme life; 4. Shaping evolution; 5. Living in the Solar System; 6. Distant worlds; 7. Are we alone?; Notes; Glossary; Reading list; Media resources; Illustration credits; Index.

  5. Healthy Living after Stroke

    MedlinePLUS

    ... After Stroke Tips for Improving Fine Motor Skills Functional Tone Management Arm Training Program Constraint-Induced Movement ... Group Stroke Group Stories Healthy Living After Stroke Nutrition Food for Thought: Heart-healthy Diet is Also ...

  6. Living with Hearing Loss

    MedlinePLUS

    ... Current Issue Past Issues Special Section: Focus on Communication Living with Hearing Loss Past Issues / Fall 2008 ... the United States suffer some form of disordered communication. The National Institute on Deafness and Other Communication ...

  7. Pathways to Assisted Living

    PubMed Central

    Ball, Mary M.; Perkins, Molly M.; Hollingsworth, Carole; Whittington, Frank J.; King, Sharon V.

    2009-01-01

    This article examines how race and class influence decisions to move to assisted living facilities. Qualitative methods were used to study moving decisions of residents in 10 assisted living facilities varying in size and location, as well as race and socioeconomic status of residents. Data were derived from in-depth interviews with 60 residents, 43 family members and friends, and 12 administrators. Grounded theory analysis identified three types of residents based on their decision-making control: proactive, compliant, and passive/resistant. Only proactive residents (less than a quarter of residents) had primary control. Findings show that control of decision making for elders who are moving to assisted living is influenced by class, though not directly by race. The impact of class primarily related to assisted-living placement options and strategies available to forestall moves. Factors influencing the decision-making process were similar for Black and White elders of comparable socioeconomic status. PMID:19756172

  8. Living with Atherosclerosis

    MedlinePLUS

    ... page from the NHLBI on Twitter. Living With Atherosclerosis Improved treatments have reduced the number of deaths ... Rate This Content: NEXT >> Featured Video What is atherosclerosis? 05/22/2014 Describes how the build-up ...

  9. Living with Oxygen Therapy

    MedlinePLUS

    ... page from the NHLBI on Twitter. Living With Oxygen Therapy Oxygen therapy helps many people function better and be ... chronic obstructive pulmonary disease) Although you may need oxygen therapy continuously or for long periods, it doesn' ...

  10. [Promoting Living Kidney Transplantation].

    PubMed

    Lin, Chiu-Chu

    2016-04-01

    Kidney transplantation is the best approach for treating patients with end stage renal disease, offering patients the best chance of returning to normal health. While the techniques used in kidney transplantation surgery are mature and highly successful, there is a severe shortage of donor organs. Statistics show a serious imbalance between organ donations and patients on the waiting list for organ transplantation. Moreover, evidence from empirical studies has shown a better transplantation outcome for patients who receive living donor transplantation than for those who receive organs from cadavers. Although using relatives as donors offers an effective way to reduce the problem of organ shortage, this strategy faces many challenges and many other factors affect the promotion of living donor transplantation. This article elaborates how cultural and psychological factors, kidney transplantation awareness, and ethics and laws impact upon living kidney donations and then proposes coping strategies for promoting living kidney transplantation. PMID:27026555

  11. Fluorescence Live Cell Imaging

    PubMed Central

    Ettinger, Andreas

    2014-01-01

    Fluorescence microscopy of live cells has become an integral part of modern cell biology. Fluorescent protein tags, live cell dyes, and other methods to fluorescently label proteins of interest provide a range of tools to investigate virtually any cellular process under the microscope. The two main experimental challenges in collecting meaningful live cell microscopy data are to minimize photodamage while retaining a useful signal-to-noise ratio, and to provide a suitable environment for cells or tissues to replicate physiological cell dynamics. This chapter aims to give a general overview on microscope design choices critical for fluorescence live cell imaging that apply to most fluorescence microscopy modalities, and on environmental control with a focus on mammalian tissue culture cells. In addition, we provide guidance on how to design and evaluate fluorescent protein constructs by spinning disk confocal microscopy. PMID:24974023

  12. ASHRAE's Living Laboratory

    SciTech Connect

    Jarnagin, Ronald E.; Brambley, Michael R.

    2008-10-01

    ASHRAE recently remodeled its headquarters building in Atlanta with the intention of making the building a LEED Gold building. As part of that renovation the building was enhanced with additional sensors and monitoring equipment to allow it to serve as a Living Laboratory for use by members and the general public to study the detailed energy use and performance of buildings. This article provides an overview of the Living Laboratory and its capabilities.

  13. Precession of the Sagittarius stream

    NASA Astrophysics Data System (ADS)

    Belokurov, V.; Koposov, S. E.; Evans, N. W.; Pearrubia, J.; Irwin, M. J.; Smith, M. C.; Lewis, G. F.; Gieles, M.; Wilkinson, M. I.; Gilmore, G.; Olszewski, E. W.; Niederste-Ostholt, M.

    2014-01-01

    Using a variety of stellar tracers - blue horizontal branch stars, main-sequence turn-off stars and red giants - we follow the path of the Sagittarius (Sgr) stream across the sky in Sloan Digital Sky Survey data. Our study presents new Sgr debris detections, accurate distances and line-of-sight velocities that together help to shed new light on the puzzle of the Sgr tails. For both the leading and the trailing tails, we trace the points of their maximal extent, or apocentric distances, and find that they lie at RL = 47.8 0.5 kpc and RT = 102.5 2.5 kpc, respectively. The angular difference between the apocentres is 93.2 3.5, which is smaller than predicted for logarithmic haloes. Such differential orbital precession can be made consistent with models of the Milky Way in which the dark matter density falls more quickly with radius. However, currently, no existing Sgr disruption simulation can explain the entirety of the observational data. Based on its position and radial velocity, we show that the unusually large globular cluster NGC 2419 can be associated with the Sgr trailing stream. We measure the precession of the orbital plane of the Sgr debris in the Milky Way potential and show that, surprisingly, Sgr debris in the primary (brighter) tails evolves differently from the secondary (fainter) tails, both in the north and the south.

  14. Transitive closure on the imagine stream processor

    SciTech Connect

    Griem, Gorden; Oliker, Leonid

    2003-11-11

    The increasing gap between processor and memory speeds is a well-known problem in modern computer architecture. The Imagine system is designed to address the processor-memory gap through streaming technology. Stream processors are best-suited for computationally intensive applications characterized by high data parallelism and producer-consumer locality with minimal data dependencies. This work examines an efficient streaming implementation of the computationally intensive Transitive Closure (TC) algorithm on the Imagine platform. We develop a tiled TC algorithm specifically for the Imagine environment, which efficiently reuses streams to minimize expensive off-chip data transfers. The implementation requires complex stream programming since the memory hierarchy and cluster organization of the underlying architecture are exposed to the Imagine programmer. Results demonstrate that limited performance of TC is achieved primarily due to the complicated data-dependencies of the blocked algorithm. This work is an ongoing effort to identify classes of scientific problems well-suited for streaming processors.

  15. Sentiment Knowledge Discovery in Twitter Streaming Data

    NASA Astrophysics Data System (ADS)

    Bifet, Albert; Frank, Eibe

    Micro-blogs are a challenging new source of information for data mining techniques. Twitter is a micro-blogging service built to discover what is happening at any moment in time, anywhere in the world. Twitter messages are short, and generated constantly, and well suited for knowledge discovery using data stream mining. We briefly discuss the challenges that Twitter data streams pose, focusing on classification problems, and then consider these streams for opinion mining and sentiment analysis. To deal with streaming unbalanced classes, we propose a sliding window Kappa statistic for evaluation in time-changing data streams. Using this statistic we perform a study on Twitter data using learning algorithms for data streams.

  16. Spectrum of turbulence in a contracting stream

    NASA Technical Reports Server (NTRS)

    Ribner, H S; Tucker, M

    1953-01-01

    The spectrum concept is employed to study the selective effect of a stream contraction on the longitudinal and lateral turbulent velocity fluctuations of the stream. By a consideration of the effect of the stream contraction on a single plane sinusoidal disturbance wave, mathematically not dissimilar to a triply periodic disturbance treated by G. I. Taylor, the effect on the spectrum tensor of the turbulence and hence on the correlation tensor is determined.

  17. Role of microbes associated with organic and inorganic substrates in phosphorus spiralling in a woodland stream

    SciTech Connect

    Elwood, J.W.; Newbold, J.D.; O'Neill, R.V.; Stark, R.W.; Singley, P.T.

    1980-01-01

    Laboratory and field experiments were conducted to determine if nutrient spiralling is primarily a biological process. The experiments were conducted to examine the role of microbial uptake and abiotic sorption onto organic and inorganic substrates in the uptake of PO/sub 4/-P in Walker Branch, a small, first-order woodland stream in east Tennessee, to estimate the total, microbial, and adsorptive pool sizes of exchangeable phosphorus associated with five particulate organic matter from this stream, and to measure the turnover rate of PO/sub 4/-P by live and sterile inorganic substrates in Walker Branch.

  18. Streaming Instability in Growing Cell Populations

    PubMed Central

    Mather, William; Mondragón-Palomino, Octavio; Danino, Tal; Hasty, Jeff; Tsimring, Lev S.

    2010-01-01

    Flows of cells growing as a quasimonolayer in a confined space can exhibit streaming, with narrow streams of fast-moving cells flowing around clusters of slowly moving cells. We observed and analyzed this phenomenon experimentally for E. coli bacteria proliferating in a microfluidic cell trap using time-lapse microscopy. We also performed continuum modeling and discrete-element simulations to elucidate the mechanism behind the streaming instability. Our analysis demonstrates that streaming can be explained by the interplay between the slow adaptation of a cell to its local microenvironment and its mobility due to changes of cell-substrate contact forces. PMID:20867071

  19. Feasibility of streaming potential measurements during hydrofracturing

    SciTech Connect

    Wurmstich, B.; Buettgenbach, T.; Morgan, F.D.

    1995-12-31

    A simple model study shows that the onset of hydraulic fracturing and eventually fracture directions may be detected in streaming potential measurements. To model streaming potential responses of hydraulic fracturing, a theory of slowly time-varying electrokinetic phenomena and a self-consistent model to describe rock conductivities in terms of intrinsic rock properties are developed. Measureable streaming potential responses are generated during the hydraulic fracturing process. The fracturing process amplifies the observable streaming potential response by up to one order of magnitude when compared to a similar experiment without fracturing. The resolution of fractures is better in monitoring wells than on the surface.

  20. Modeling ice streams: Derived quantities

    NASA Technical Reports Server (NTRS)

    Fastook, James

    1993-01-01

    The model addressed is a finite-element, map-plane, time-dependent, column-averaged continuity equation solver. The key to the fitting process involves the balance between ice motion dominated by flow in internal layers, and ice motion dominated by sliding at the bed. The fitting process involves an iterative process carried out in the time domain. Beginning with the portion of the ice sheet being modeled identical to the present ice sheet with uniform flow, sliding, and fraction specified at nominal values, the model monitors each nodal point surface elevation. As the calculated surface elevation deviates from the present surface, a correction proportional to the difference is applied to selected parameter sets. This correction is in a sense that would tend to improve the fit at the particular nodal point. A calculated surface elevation that was higher than the present surface would result in an increased fraction, which would tend to lower the calculated surface (if the flow or sliding constant were being used as the fitting parameter, they would be lowered to improve the fit). This process is allowed to proceed as long as is necessary for the situation to stabilize. Typically, this takes tens of thousands of model years, but the rate is dependent on other external forcings such as the accumulation rate. The primary result is that while a typical sample of ice streams from around Antarctica can be fitted quite reasonably using only the fraction of the velocity due to sliding, a different mechanism seems to be in play along the Siple Coast, where reduced sliding constants are required to attain a reasonable fit. Flow is more strongly channelized in this region, and velocities are, in general, higher than are observed in other regions. It is unlikely that the mechanism that controls the ice movement along the Siple Coast is exactly similar to the mechanisms in the other ice streams. The concept of deformable sediments and their contribution to the fast flow along the Siple Coast may have limited applicability to other Antarctic ice streams.

  1. Living in the question.

    PubMed

    Flower, J

    1999-01-01

    We live in a fast moving-world. Business has accelerated to breathtaking speeds in the 1990s--and in the last few years the afterburner has really kicked in. The speed of change is overwhelming. Especially in health care, who has time to "live in the question?" We need to decide things quickly, get the decision out of the way, and move on, right? Maybe. Biology shows us that you can't plan ahead very far. New things come along that you don't even have a category for, and therefore you don't even see them. Things are going to happen that you literally have no notion are even possible. The key to succeeding in this environment? Don't plan ahead. Stay curious. Make small bets. Build organizational hothouses. Feed the seedlings that grow. The challenge is to remain curious, to live in the question, both personally and organizationally. PMID:10557490

  2. THERMAL HETEROGENEITY, STREAM CHANNEL MORPHOLOGY, AND SALMONID ABUNDANCE IN NORTHEASTERN OREGON STREAMS

    EPA Science Inventory

    Heterogeneity in stream water temperatures created by local influx of cooler subsurface waters into geomorphically complex stream channels was associated with increased abundance of rainbow trout (Oncorhynchus mykiss) and chinook salmon (O. tshawytscha) in northeastern Oregon. Th...

  3. Living My Family's Story

    PubMed Central

    Underhill, Meghan L.; Lally, Robin M.; Kiviniemi, Marc T.; Murekeyisoni, Christine; Dickerson, Suzanne S.

    2013-01-01

    Background Based on known or suggested genetic risk factors, a growing number of women now live with knowledge of a potential cancer diagnosis that may never occur. Given this, it is important to understand the meaning of living with high risk for hereditary breast cancer. Objective The objective of the study was to explore how women at high risk for hereditary breast cancer (1) form self-identity, (2) apply self-care strategies toward risk, and (3) describe the meaning of care through a high-risk breast program. Methods Interpretive hermeneutic phenomenology guided the qualitative research method. Women at high risk for hereditary breast cancer were recruited from a high-risk breast program. Open-ended interview questions focused on experiences living as women managing high risk for breast cancer. Consistent with hermeneutic methodology, the principal investigator led a team to analyze the interview transcripts. Results Twenty women participated in in-depth interviews. Analysis revealed that women describe their own identity based on their family story and grieve over actual and potential familial loss. This experience influences self-care strategies, including seeking care from hereditary breast cancer risk experts for early detection and prevention, as well as maintaining a connection for early treatment when diagnosis occurs. Conclusions Healthy women living with high risk for hereditary breast cancer are living within the context of their family cancer story, which influences how they define themselves and engage in self-care. Implications for Practice Findings present important practical, research, and policy information regarding health promotion, psychosocial assessment, and support for women living with this risk. PMID:22544165

  4. Cryopreservation of Living Organs

    NASA Astrophysics Data System (ADS)

    Tanasawa, Ichiro; Nagata, Shinichi; Kimura, Naohiro

    Cryopreservation is considered to be the most promising way of preserving living organs or tissues for a long period of time without casuing any damage to their biological functions. However, cryopreservation has been succeeded only for simple and small-size tissues such as spermatozoon, ovum, erythrocyte, bone marrow and cornea. Cryopreservation of more complex and large-scale organs are not yet succssful. The authors have attempted to establish a technique for cryopreservation of larger living organs. An experiment was carried out using daphnia (water flea). The optimum rates of freezing and thawing were determined together with the optimum selection of cryoprotectant. High recovery rate was achieved under these conditions.

  5. Streaming Multiframe Deconvolutions on GPUs

    NASA Astrophysics Data System (ADS)

    Lee, M. A.; Budavri, T.

    2015-09-01

    Atmospheric turbulence distorts all ground-based observations, which is especially detrimental to faint detections. The point spread function (PSF) defining this blur is unknown for each exposure and varies significantly over time, making image analysis difficult. Lucky imaging and traditional co-adding throws away lots of information. We developed blind deconvolution algorithms that can simultaneously obtain robust solutions for the background image and all the PSFs. It is done in a streaming setting, which makes it practical for large number of big images. We implemented a new tool that runs of GPUs and achieves exceptional running times that can scale to the new time-domain surveys. Our code can quickly and effectively recover high-resolution images exceeding the quality of traditional co-adds. We demonstrate the power of the method on the repeated exposures in the Sloan Digital Sky Survey's Stripe 82.

  6. Incremental learning from stream data.

    PubMed

    He, Haibo; Chen, Sheng; Li, Kang; Xu, Xin

    2011-12-01

    Recent years have witnessed an incredibly increasing interest in the topic of incremental learning. Unlike conventional machine learning situations, data flow targeted by incremental learning becomes available continuously over time. Accordingly, it is desirable to be able to abandon the traditional assumption of the availability of representative training data during the training period to develop decision boundaries. Under scenarios of continuous data flow, the challenge is how to transform the vast amount of stream raw data into information and knowledge representation, and accumulate experience over time to support future decision-making process. In this paper, we propose a general adaptive incremental learning framework named ADAIN that is capable of learning from continuous raw data, accumulating experience over time, and using such knowledge to improve future learning and prediction performance. Detailed system level architecture and design strategies are presented in this paper. Simulation results over several real-world data sets are used to validate the effectiveness of this method. PMID:22057060

  7. Drawdown and stream depletion produced by pumping in the vicinity of a partially penetrating stream

    USGS Publications Warehouse

    Butler, J.J., Jr.; Zlotnik, V.A.; Tsou, M.-S.

    2001-01-01

    Commonly used analytical approaches for estimation of pumping-induced drawdown and stream depletion are based on a series of idealistic assumptions about the stream-aquifer system. A new solution has been developed for estimation of drawdown and stream depletion under conditions that are more representative of those in natural systems (finite width stream of shallow penetration adjoining an aquifer of limited lateral extent). This solution shows that the conventional assumption of a fully penetrating stream will lead to a significant overestimation of stream depletion (> 100 %) in many practical applications. The degree of overestimation will depend on the value of the stream leakance parameter and the distance from the pumping well to the stream. Although leakance will increase with stream width, a very wide stream will not necessarily be well represented by a model of a fully penetrating stream. The impact of lateral boundaries depends upon the distance from the pumping well to the stream and the stream leakance parameter. In most cases, aquifer width must be on the order of hundreds of stream widths before the assumption of a laterally infinite aquifer is appropriate for stream-depletion calculations. An important assumption underlying this solution is that stream-channel penetration is negligible relative to aquifer thickness. However, an approximate extension to the case of nonnegligible penetration provides reasonable results for the range of relative penetrations found in most natural systems (up to 85%). Since this solution allows consideration of a much wider range of conditions than existing analytical approaches, it could prove to be a valuable new tool for water management design and water rights adjudication purposes.

  8. STAR STREAM FOLDING BY DARK GALACTIC SUBHALOS

    SciTech Connect

    Carlberg, R. G.

    2009-11-10

    Star streams in galactic halos are long, thin, unbound structures that will be disturbed by the thousands of dark matter subhalos that are predicted to be orbiting within the main halo. A subhalo generally induces a localized wave in the stream which often evolves into a 'z-fold' as an initially trailing innermost part rotates faster than an initially leading outermost part. The folding, which becomes increasingly complex with time, leads to an apparent velocity dispersion increase and thickening of the stream. We measure the equivalent velocity dispersion around the local mean in the simulations, finding that it rises to about 10 km s{sup -1} after 5 Gyr and 20 km s{sup -1} after 13 Gyr. The currently available measurements of the velocity dispersion of halo star streams range from as small as 2 km s{sup -1} to slightly over 20 km s{sup -1}. The streams with velocity dispersions of 15-20 km s{sup -1} are compatible with what subhalo heating would produce. A dynamical understanding of the low velocity dispersion streams depends on the time since the progenitor's tidal disruption into a thin stream. If the streams are nearly as old as their stars then subhalos cannot be present with the predicted numbers and masses. However, the dynamical age of the streams can be significantly less than the stars. If the three lowest velocity streams are assigned ages of 3 Gyr, they are in conflict with the subhalo heating. The main conclusion is that star stream heating is a powerful and simple test for subhalo structure.

  9. Stream bank erosion in grazed pasture stream reaches of southern Iowa, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stream bank erosion in agricultural landscapes is a major pathway for non-point source sediment and phosphorus loading of receiving waters. The objective of this study was to assess the relationship between the numbers of high stream stage events, as they directly reflect higher erosive stream flow,...

  10. ACID-BASE STATUS OF PENNSYLVANIA STREAMS: RESULTS FROM THE NATIONAL STREAM SURVEY

    EPA Science Inventory

    The National Stream Survey (NSS) conducted by the Environmental Protection Agency in the spring of 1986 sampled 82 stream reaches within the state of Pennsylvania, representing a target population of 9900 stream reaches that are potentially sensitive to acidification. After exclu...

  11. Learning from Live Theater

    ERIC Educational Resources Information Center

    Greene, Jay P.; Hitt, Collin; Kraybill, Anne; Bogulski, Cari A.

    2015-01-01

    Culturally enriching field trips matter. They produce significant benefits for students on a variety of educational outcomes that schools and communities care about. This experiment on the effects of field trips to see live theater demonstrates that seeing plays is an effective way to teach academic content; increases student tolerance by

  12. Microholography of Living Organisms.

    ERIC Educational Resources Information Center

    Solem, Johndale C.; Baldwin, George C.

    1982-01-01

    By using intense pulsed coherent x-ray sources it will be possible to obtain magnified three-dimensional images of living elementary biological structures at precisely defined instants. Discussed are sources/geometrics for x-ray holography, x-radiation interactions, factors affecting resolution, recording the hologram, high-intensity holography,

  13. Living with Pulmonary Embolism

    MedlinePLUS

    ... Living With Clinical Trials Links Related Topics Arrhythmia Deep Vein Thrombosis Lung Ventilation/Perfusion Scan Overweight and Obesity Send ... Once you've had PE (with or without deep vein thrombosis (DVT)), you're at higher risk of having ...

  14. Test Pattern For Living.

    ERIC Educational Resources Information Center

    Johnson, Nicholas

    The lives of Americans today are ruled by interlocking corporations. These corporations together present only one kind of life as viable: the consumer's life. Television is their main means of presenting this view. One cannot choose something he does not know about, and many Americans are not sufficiently informed of the alternatives to make an

  15. You Live, You Learn

    ERIC Educational Resources Information Center

    Biesta, Gert

    2008-01-01

    The Learning Lives project, a four-year study into the learning biographies and trajectories of adults, was conducted by a team of researchers from the universities of Stirling, Exeter, Brighton and Leeds as part of the Teaching and Learning Research Programme (TLRP) of the Economic and Social Research Council, and has just been completed. Whereas

  16. Live, Learn & Teach

    ERIC Educational Resources Information Center

    Eder, Sid; Williamson, Jed

    1977-01-01

    Describes the Live, Learn and Teach program, an eight-day wilderness experience in New Hampshire's White Mountains, designed to develop student teacher relations. It includes six weeks of curriculum-design sessions and a practicum in which teaching teams experiment with new skills and behaviors as they design and carry out an activity-centered and…

  17. The Living Periodic Table

    ERIC Educational Resources Information Center

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  18. Learning from Live Theater

    ERIC Educational Resources Information Center

    Greene, Jay P.; Hitt, Collin; Kraybill, Anne; Bogulski, Cari A.

    2015-01-01

    Culturally enriching field trips matter. They produce significant benefits for students on a variety of educational outcomes that schools and communities care about. This experiment on the effects of field trips to see live theater demonstrates that seeing plays is an effective way to teach academic content; increases student tolerance by…

  19. The Living Periodic Table

    ERIC Educational Resources Information Center

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the

  20. Live-cell imaging

    PubMed Central

    Cole, Richard

    2014-01-01

    It would be hard to argue that live-cell imaging has not changed our view of biology. The past 10 years have seen an explosion of interest in imaging cellular processes, down to the molecular level. There are now many advanced techniques being applied to live cell imaging. However, cellular health is often under appreciated. For many researchers, if the cell at the end of the experiment has not gone into apoptosis or is blebbed beyond recognition, than all is well. This is simply incorrect. There are many factors that need to be considered when performing live-cell imaging in order to maintain cellular health such as: imaging modality, media, temperature, humidity, PH, osmolality, and photon dose. The wavelength of illuminating light, and the total photon dose that the cells are exposed to, comprise two of the most important and controllable parameters of live-cell imaging. The lowest photon dose that achieves a measureable metric for the experimental question should be used, not the dose that produces cover photo quality images. This is paramount to ensure that the cellular processes being investigated are in their in vitro state and not shifted to an alternate pathway due to environmental stress. The timing of the mitosis is an ideal canary in the gold mine, in that any stress induced from the imaging will result in the increased length of mitosis, thus providing a control model for the current imagining conditions. PMID:25482523

  1. Living with Parkinson's

    MedlinePLUS

    ... Tips from the Health Care Team Finding Resources Parkinson's HelpLine Learn More Educational Materials Do you want ... resources & more. Order Free Materials Today Living with Parkinson’s “Parkinson’s is a part of my life, but ...

  2. Geriatric Live Interactive Teleconferencing.

    ERIC Educational Resources Information Center

    Parham, Iris A.; Wood, Joan

    1985-01-01

    This document includes a successful model for implementing educational teleconferencing, the Geriatric Live Interactive Teleconferencing program at Virginia Commonwealth University (VCU). As a vehicle for continuing professional education, teleconferencing can transmit the latest information to large numbers of health professionals in a variety of…

  3. Living Systems Energy Module

    SciTech Connect

    1995-09-26

    The Living Systems Energy Module, renamed Voyage from the Sun, is a twenty-lesson curriculum designed to introduce students to the major ways in which energy is important in living systems. Voyage from the Sun tells the story of energy, describing its solar origins, how it is incorporated into living terrestrial systems through photosynthesis, how it flows from plants to herbivorous animals, and from herbivores to carnivores. A significant part of the unit is devoted to examining how humans use energy, and how human impact on natural habitats affects ecosystems. As students proceed through the unit, they read chapters of Voyage from the Sun, a comic book that describes the flow of energy in story form (Appendix A). During the course of the unit, an ``Energy Pyramid`` is erected in the classroom. This three-dimensional structure serves as a classroom exhibit, reminding students daily of the importance of energy and of the fragile nature of our living planet. Interactive activities teach students about adaptations that allow plants and animals to acquire, to use and to conserve energy. A complete list of curricular materials and copies of all activity sheets appear in Appendix B.

  4. Living or Nonliving?

    ERIC Educational Resources Information Center

    Legaspi, Britt; Straits, William

    2011-01-01

    Categorizing organisms as living or nonliving things may seem to be intuitive by nature. Yet, it is regulated by scientific criteria. Students come to school with rules already in place. Their categorizing criteria have already been influenced by their personal experiences, also known as observations and inferences. They believe that all things

  5. Family Living Supplement.

    ERIC Educational Resources Information Center

    Truitt, Debbie

    This family living supplement contains 125 supplemental ideas and strategies designed to help vocational home economics teachers increase student motivation and enrich the teaching process. Ideas and strategies are organized into seven sections. These are career planning, securing a job, and career success; managing financial resources, buying

  6. New Lives of Teachers

    ERIC Educational Resources Information Center

    Day, Christopher

    2012-01-01

    The work and lives of teachers have always been subject to external influence as those who are nearing the end of their careers will attest, but it is arguable that what is new over the last two decades is the pace, complexity, and intensity of change as governments have responded to the shrinking world of economic competitiveness and social…

  7. Dementia and Assisted Living

    ERIC Educational Resources Information Center

    Hyde, Joan; Perez, Rosa; Forester, Brent

    2007-01-01

    Purpose: This article presents an overview of what is known about dementia services in assisted living settings and suggests areas for future research. Design and Methods: We undertook a search of Medline, the "Journals of Gerontology," and "The Gerontologist." We then organized publications dealing with the target subject into 10 topic areas and…

  8. Design for Living

    ERIC Educational Resources Information Center

    Rosenblum, Todd

    2011-01-01

    Bringing a newborn home from the hospital can come with stress for any parent. Coming home with twins can be double the stress. This article shares the story of a couple faced with this situation 12 years ago with the birth of twins, one was born with complications. They lived in a Colonial until the twins were almost five years old, at which time

  9. Effects of Context on Auditory Stream Segregation

    ERIC Educational Resources Information Center

    Snyder, Joel S.; Carter, Olivia L.; Lee, Suh-Kyung; Hannon, Erin E.; Alain, Claude

    2008-01-01

    The authors examined the effect of preceding context on auditory stream segregation. Low tones (A), high tones (B), and silences (-) were presented in an ABA-pattern. Participants indicated whether they perceived 1 or 2 streams of tones. The A tone frequency was fixed, and the B tone was the same as the A tone or had 1 of 3 higher frequencies.…

  10. MODELING STREAM CHANNEL ADJUSTMENT TO WOODY VEGETATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    River restoration and bank stabilization programs often use vegetation for improving stream corridor habitat, aesthetic, and function. Yet no study has examined the use of managed vegetation plantings to transform a straight, degraded stream corridor into a more functional, aesthetically-pleasing m...

  11. Incomplete Mixing in a Small, Urban stream

    NASA Astrophysics Data System (ADS)

    Ryan, R. J.; Boufadel, M. C.

    2006-05-01

    Conservative solute tracer experiments were conducted in Indian Creek, a small urban stream located in Philadelphia, Pennsylvania, USA. Estimated flow rates were between 46 L s-1 and 81 L s-1, average stream width was 5.5 m and average stream depth was 0.2 m. Given these dimensions, most researchers would think it reasonable to assume that the stream is completely mixed vertically and horizontally. However, we found that the stream was not vertically completely mixed in a 0.95 m deep, 30 m long pool. The limited mixing was demonstrated by the vertical stratification of a tracer cloud which was completely mixed both laterally and vertically across the stream prior to entering the pool. We suggest that the cause of limited mixing is due to a balance between groundwater inflow and transverse dispersion at the cross section. We show that the unsupported assumption of complete mix may result in a wide range, and thus increased uncertainty, of the values of stream flow and longitudinal dispersion coefficient estimated from these data. We conclude that the assumption of complete mix and one-dimensional modeling must be checked against actual field conditions, even in small streams.

  12. Streams-C Scheduler and Library

    Energy Science and Technology Software Center (ESTSC)

    2001-12-04

    The scheduler accepts a preprocessed C program with optional Streams-C extensions. It translates it to a normalized form with additional information for scheduling it on a reconfigurable architecture. The resulting file is accepted by the Streams-C VHDL generator, not part of this package.

  13. Streaming for Mathematics in Victorian Secondary Schools

    ERIC Educational Resources Information Center

    Forgasz, Helen

    2010-01-01

    Streaming (or ability grouping) for mathematics learning is a contentious issue. It can also be considered an issue of equity or social justice as some students may be adversely affected by the practice. Currently, the Victorian Department of Education and Early Childhood Development (DEECD) does not appear to have clear guidelines on streaming.…

  14. COMPARTMENTAL MODEL OF NITRATE RETENTION IN STREAMS

    EPA Science Inventory

    A compartmental modeling approach is presented to route nitrate retention along a cascade of stream reach sections. A process transfer function is used for transient storage equations with first order reaction terms to represent nitrate uptake in the free stream, and denitrifica...

  15. GAPS IN THE GD-1 STAR STREAM

    SciTech Connect

    Carlberg, R. G.; Grillmair, C. J. E-mail: carl@ipac.caltech.edu

    2013-05-10

    GD-1 is a long, thin, Milky Way star stream that has readily visible density variations along its length. We quantify the locations, sizes, and statistical significance of the density structure, i.e., gaps, using a set of scaled filters. The shapes of the filters are based on the gaps that develop in simulations of dark matter sub-halos crossing a star stream. The high Galactic latitude 8.4 kpc long segment of GD-1 that we examine has 8 {+-} 3 gaps of 99% significance or greater, with the error estimated on the basis of tests of the gap-filtering technique. The cumulative distribution of gaps more than three times the width of the stream is in good agreement with predictions for dark matter sub-halo encounters with cold star streams. The number of gaps narrower than three times the width of the GD-1 stream falls well below the cold stream prediction which is taken into account for the gap creation rate integrated over all sizes. Simple warm stream simulations scaled to GD-1 show that the falloff in gaps is expected for sub-halos below a mass of 10{sup 6} M{sub Sun }. The GD-1 gaps requires 100 sub-halos >10{sup 6} M{sub Sun} within 30 kpc, the apocenter of GD-1 orbit. These results are consistent with LCDM sub-halo predictions but further improvements in stream signal-to-noise and gap modeling will be welcome.

  16. THE PAL 5 STAR STREAM GAPS

    SciTech Connect

    Carlberg, R. G.; Hetherington, Nathan; Grillmair, C. J. E-mail: hetherington@astro.utoronto.ca

    2012-11-20

    Pal 5 is a low-mass, low-velocity-dispersion, globular cluster with spectacular tidal tails. We use the Sloan Digital Sky Survey Data Release 8 data to extend the density measurements of the trailing star stream to 23 deg distance from the cluster, at which point the stream runs off the edge of the available sky coverage. The size and the number of gaps in the stream are measured using a filter which approximates the structure of the gaps found in stream simulations. We find 5 gaps that are at least 99% confidence detections with about a dozen gaps at 90% confidence. The statistical significance of a gap is estimated using bootstrap resampling of the control regions on either side of the stream. The density minimum closest to the cluster is likely the result of the epicyclic orbits of the tidal outflow and has been discounted. To create the number of 99% confidence gaps per unit length at the mean age of the stream requires a halo population of nearly a thousand dark matter sub-halos with peak circular velocities above 1 km s{sup -1} within 30 kpc of the galactic center. These numbers are a factor of about three below cold stream simulation at this sub-halo mass or velocity but, given the uncertainties in both measurement and more realistic warm stream modeling, are in substantial agreement with the LCDM prediction.

  17. Ecosystem Services Provided by Stream Fishes

    EPA Science Inventory

    Stream fish provide important services to people, including recreation and food, regulation of ecosystem processes, and aesthetic benefits. If the services provided by fish in different streams can be measured, then they can be valued and considered in restoration decisions. We...

  18. INDICATORS OF HYDROLOGIC PERMANENCE IN HEADWATER STREAMS

    EPA Science Inventory

    Headwater intermittent streams lie at the aquatic-terrestrial interface and represent much of our nation's stream miles. Recent court cases concerning the definition of jurisdictional waters under the Clean Water Act have illuminated a need to better understand the characteristi...

  19. Neotropical Amphibian Declines Affect Stream Ecosystem Properties

    NASA Astrophysics Data System (ADS)

    Connelly, S.; Pringle, C. M.; Bixby, R. J.; Whiles, M. R.; Lips, K. R.; Brenes, R.; Colon-Gaud, J. C.; Kilham, S.; Hunte-Brown, M.

    2005-05-01

    Global declines of amphibians are well documented, yet effects of these dramatic losses on ecosystem structure and function are poorly understood. As part of a larger collaborative project, we compared two upland Panamanian streams. Both streams are biologically and geologically similar; however, one stream (Fortuna) has recently experienced almost complete extirpation of stream-dwelling frogs, while the other (Cope) still has intact populations. We experimentally excluded tadpoles from localized areas in each stream. We then compared chlorophyll a, algal community composition, ash-free dry mass (AFDM), inorganic matter, and insect assemblages in control and exclusion areas. Additionally, we sampled the natural substrate of both streams monthly for chlorophyll a, algal community composition, AFDM, and inorganic matter. At Cope, chlorophyll a, AFDM, and inorganic matter were greater in areas where tadpoles were excluded than in their presence. Numbers of dominant algal species (e.g., Nupela praecipua and Eunotia siolii) were greater in the exclusion versus control treatments. Monthly sampling of natural substrate indicated higher chlorophyll a and AFDM at Cope compared to Fortuna. Our data suggest that stream-dwelling anuran larvae have significant impacts on algal communities. These results also have implications for predicting the relevance of short-term experimental manipulations to long-term, whole-stream processes.

  20. MECHANICS OF STREAM-BORNE WOODY DEBRIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large woody debris is increasingly regarded as an integral component of stream stabilization and restoration programs. Unravelling the dynamics of complex interaction of multiple logs among themselves and with the stream environs must start with a correct specification of all the forces acting on i...

  1. The Pal 5 Star Stream Gaps

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.; Grillmair, C. J.; Hetherington, Nathan

    2012-11-01

    Pal 5 is a low-mass, low-velocity-dispersion, globular cluster with spectacular tidal tails. We use the Sloan Digital Sky Survey Data Release 8 data to extend the density measurements of the trailing star stream to 23 deg distance from the cluster, at which point the stream runs off the edge of the available sky coverage. The size and the number of gaps in the stream are measured using a filter which approximates the structure of the gaps found in stream simulations. We find 5 gaps that are at least 99% confidence detections with about a dozen gaps at 90% confidence. The statistical significance of a gap is estimated using bootstrap resampling of the control regions on either side of the stream. The density minimum closest to the cluster is likely the result of the epicyclic orbits of the tidal outflow and has been discounted. To create the number of 99% confidence gaps per unit length at the mean age of the stream requires a halo population of nearly a thousand dark matter sub-halos with peak circular velocities above 1 km s-1 within 30 kpc of the galactic center. These numbers are a factor of about three below cold stream simulation at this sub-halo mass or velocity but, given the uncertainties in both measurement and more realistic warm stream modeling, are in substantial agreement with the LCDM prediction.

  2. EFFECTS OF ACIDIFICATION ON STREAM ECOSYSTEMS

    EPA Science Inventory

    The purpose of the paper is to summarize known effects of acid precipitation on stream ecosystems, with emphasis on the Great Lakes region. Unfortunately, very little research has been conducted on streams in much of the Great Lakes region. Thus, data will be utilized from other ...

  3. Stabilization of tokamak plasma by lithium streams

    SciTech Connect

    L.E. Zakharov

    2000-08-07

    The stabilization theory of free-boundary magnetohydrodynamic instabilities in tokamaks by liquid lithium streams driven by magnetic propulsion is formulated. While the conventional, wall-locked, resistive wall mode can be well suppressed by the flow, a new, stream-locked mode determines the limits of the flow stabilization.

  4. National River and Stream Assessment Monitoring Design

    EPA Science Inventory

    The USEPA designed the National River and Stream Assessment (NRSA) in 2007 and field sampling was completed in 2008-9. The objective of the assessment is to estimate the ecological condition of river and streams nationally. This paper describes the national survey design and re...

  5. Fire Service Training. Fire Stream Practices. (Revised).

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Community Colleges, Raleigh.

    One of a set of fourteen instructional outlines for use in a course to train novice firemen, this guide covers the topic of fire streams. The various types of fire streams are identified as well as the methods used to produce them, emphasizing the operation of nozzles and the different kinds of friction loss. Designed to be used with the Robert J.

  6. Effects of Context on Auditory Stream Segregation

    ERIC Educational Resources Information Center

    Snyder, Joel S.; Carter, Olivia L.; Lee, Suh-Kyung; Hannon, Erin E.; Alain, Claude

    2008-01-01

    The authors examined the effect of preceding context on auditory stream segregation. Low tones (A), high tones (B), and silences (-) were presented in an ABA-pattern. Participants indicated whether they perceived 1 or 2 streams of tones. The A tone frequency was fixed, and the B tone was the same as the A tone or had 1 of 3 higher frequencies.

  7. COHO SALMON DEPENDENCE ON INTERMITTENT STREAMS

    EPA Science Inventory

    In February 2006, the US Supreme Court heard cases that may affect whether intermittent streams are jurisdictional waters under the Clean Water Act. In June 2006, however, the cases were remanded to the circuit court, leaving the status of intermittent streams uncertain once agai...

  8. The Gulf Stream and Density of Fluids

    ERIC Educational Resources Information Center

    Landstrom, Erich

    2006-01-01

    A few kilometers from the shores of Palm Beach County, Florida, is the Gulf Stream current--a remarkable "river" within an ocean. The current's journey across the Atlantic Ocean connects southeast Florida and southwest Great Britain as it streams steadily north at speeds of 97 km a day; moving 100 times as much water as all the rivers on Earth.…

  9. The Gulf Stream and Density of Fluids

    ERIC Educational Resources Information Center

    Landstrom, Erich

    2006-01-01

    A few kilometers from the shores of Palm Beach County, Florida, is the Gulf Stream current--a remarkable "river" within an ocean. The current's journey across the Atlantic Ocean connects southeast Florida and southwest Great Britain as it streams steadily north at speeds of 97 km a day; moving 100 times as much water as all the rivers on Earth.

  10. Key stream/sediment exchanges of water and heat near stream mouths

    NASA Astrophysics Data System (ADS)

    Constantz, J. E.; Naranjo, R. C.; Niswonger, R. G.; Neilson, B. T.; Allander, K.; Zamora, C.; Smith, D. W.; Stonestrom, D. A.

    2014-12-01

    The section of stream discharging to a lake or other surface-water body is referred to as the stream mouth, a stream reach with rapidly changing hydrologic conditions, leading to unique aquatic and benthic ecology, as well as a visibly active fishery habitat. Of environmental significance, bridges, control structures, channelization and foot traffic are common near stream mouths, warranting comparisons of natural and channelized stream mouths. The present work completes the first investigation focusing specifically on the hydrology of surface-water/sediment exchanges at stream-mouth reaches discharging to lakes and compares these exchanges to those measured along the nearby shoreline in both a qualitative and quantitative manner. Heat and water exchanges for two common types of stream mouths (a natural stream with a summer barrier bar and a channelized stream mouth) are compared with comparable exchanges along the nearby shoreline on the north shore of Lake Tahoe located in the Central Sierra Nevada Mountain Range (CA/NV, US). The study site was selected partially due the abundance of streams discharging into the lake of both a natural and channelized nature (~30 small streams with a large number of both types of stream mouths). Heat and water exchanges were both qualitatively and quantitatively distinct for the three types of hydrologic settings, with (1) cool, low velocity, longitudinal (hyporheic) flowpaths observed below the channelized stream mouth, discharging beneath the warmer, more buoyant lakeshore water, (2) the nearby shoreline receiving relatively warm, higher velocity discharge and (3) for the natural stream mouth, there was strong diurnal temperature pattern in groundwater discharging through the seasonal barrier beach to the lake. Impacts of strong 2013 wave action on exchanges were also distinct for the three settings, with (1) channelization allowing waves to extend well upstream, (2) a lesser invasive impact in the shoreline swash zone exchanges and (3) the least spatial impact on the natural stream with its seasonal barrier beach shielding the mouth.

  11. Effects of urbanization and urban stream restoration on the physical and biological structure of stream ecosystems.

    PubMed

    Violin, Christy R; Cada, Peter; Sudduth, Elizabeth B; Hassett, Brooke A; Penrose, David L; Bernhardt, Emily S

    2011-09-01

    Streams, as low-lying points in the landscape, are strongly influenced by the stormwaters, pollutants, and warming that characterize catchment urbanization. River restoration projects are an increasingly popular method for mitigating urban insults. Despite the growing frequency and high expense of urban stream restoration projects, very few projects have been evaluated to determine whether they can successfully enhance habitat structure or support the stream biota characteristic of reference sites. We compared the physical and biological structure of four urban degraded, four urban restored, and four forested streams in the Piedmont region of North Carolina to quantify the ability of reach-scale stream restoration to restore physical and biological structure to urban streams and to examine the assumption that providing habitat is sufficient for biological recovery. To be successful at mitigating urban impacts, the habitat structure and biological communities found in restored streams should be more similar to forested reference sites than to their urban degraded counterparts. For every measured reach- and patch-scale attribute, we found that restored streams were indistinguishable from their degraded urban stream counterparts. Forested streams were shallower, had greater habitat complexity and median sediment size, and contained less-tolerant communities with higher sensitive taxa richness than streams in either urban category. Because heavy machinery is used to regrade and reconfigure restored channels, restored streams had less canopy cover than either forested or urban streams. Channel habitat complexity and watershed impervious surface cover (ISC) were the best predictors of sensitive taxa richness and biotic index at the reach and catchment scale, respectively. Macroinvertebrate communities in restored channels were compositionally similar to the communities in urban degraded channels, and both were dissimilar to communities in forested streams. The macroinvertebrate communities of both restored and urban degraded streams were correlated with environmental variables characteristic of degraded urban systems. Our study suggests that reach-scale restoration is not successfully mitigating for the factors causing physical and biological degradation. PMID:21939035

  12. Satellite imagery of the onset of streaming flow of ice streams C and D, West Antarctica

    USGS Publications Warehouse

    Hodge, S.M.; Doppelhammer, S.K.

    1996-01-01

    Five overlapping Landsat multispectral scanner satellite images of the interior of the West Antarctic ice sheet were enhanced with principal component analysis, high-pass filtering, and linear contrast stretching and merged into a mosaic by aligning surface features in the overlap areas. The mosaic was registered to geodetic coordinates, to an accuracy of about 1 km, using the five scene centers as control points. The onset of streaming flow of two tributaries of ice stream C and one tributary of ice stream D is visible in the mosaic. The onset appears to occur within a relatively short distance, less than the width of the ice stream, typically at a subglacial topographic feature such as a step or ridge. The ice streams extend farther up into the interior than previously mapped. Ice stream D starts about 150 km from the ice divide, at an altitude of about 1500 m, approximately halfway up the convex-upward dome shape of the interior ice sheet. Ice stream D is relatively much longer than ice stream C, possibly because ice stream D is currently active whereas ice stream C is currently inactive. The grounded portion of the West Antarctic ice sheet is perhaps best conceptualized as an ice sheet in which ice streams are embedded over most of its area, with slow moving ice converging into fast moving ice streams in a widely distributed pattern, much like that of streams and rivers in a hydrologic basin. A relic margin appears to parallel most of the south margin of the tributary of ice stream D, separated from the active shear margin by about 10 km or less for a distance of over 200 km. This means there is now evidence for recent changes having occurred in three of the five major ice streams which drain most of West Antarctica (B, C, and D), two of which (B and D) are currently active.

  13. The thermomechanics of ice-stream margins

    NASA Astrophysics Data System (ADS)

    Suckale, Jenny; Elsworth, Cooper; Platt, John; Perol, Thibaut; Rice, James

    2015-04-01

    The mass balance of the West Antarctic ice sheet depends primarily on the location and flow speed of arterial drainage routes called ice streams, which represent localized zones of rapid ice flow separated by ridges of comparatively stagnant ice. Our understanding of ice-stream dynamics and our ability to predict the flow velocity and configuration of ice streams in light of changing environmental conditions, however, is incomplete. One main challenge in current models of ice streams is the treatment of the shear margin, which plays an important role in the force balance of an active ice stream. The lack of a clear correlation between topography and ice-stream location on the Ross ice shelf in combination with observations of migrating ice-stream margins suggest that a physical mechanism must exist that determines the location of the margin and the flow speed of the stream self-consistently. Three possible mechanisms are the transition from a frozen to a temperate bed in the shear margin, the formation of a subglacial drainage channel or the existence of sticky spots. The goal of this study is to test whether and how these three mechanisms contribute to ice-stream dynamics. We propose a 2D thermo-mechanical model representing a cross-section through the ice-stream margin perpendicular to the downstream flow direction. We assume that the ice flows over a bed consisting of Coulomb-plastic till. The position and extent of the ice stream is determined by where the shear stress at the bed attains the local and spatially variable yield stress. If the basal stress falls below the yield stress, the ice is assumed to lock to the bed. While a simplified variation of this model setup can be solved analytically, we adopt a numerical treatment to be able to incorporate a realistic ice rheology. We validate our numerical approach both against previous analytical solutions and against observations. We find that the rapid velocity increase across the shear margins of the active ice streams is indicative of a temperate zone at depth, where the heat production from lateral shear is most intense. A transition from a temperate to a frozen bed or the existence of drainage channels may both play an important role in the dynamics of active ice streams, but are probably less important close to the initiation region. All three mechanisms, however, are prone to instability suggesting that the ice streams on the Ross ice shelf might be in a precarious balance.

  14. Comet Machholz and the Quadrantid meteor stream

    NASA Astrophysics Data System (ADS)

    Jones, J.; Jones, W.

    1993-04-01

    Until quite recently, the Quadrantid meteor stream was considered to be an 'orphan'. Because of the difficulty in accounting for the large difference in the longitudes of the ascending nodes, McIntosh (1990) suggested that Comet Machholz and the stream have a sibling rather than a parent-child relationship. Gonczi et al. (1992) proposed that gravitational perturbations by Jupiter may be amplified sufficiently by the 2:1 resonance of the stream with Jupiter to explain the difference in the longitudes of ascending nodes if the stream was born when the comet's perihelion distance was last at its minimum about 4000 yr ago. In this paper, we show by computer simulations that, if the comet was captured at its last close approach with Jupiter about 2200 yr ago, there has been sufficient time for the resulting stream to produce most of the features of the presently observed Quadrantid/Arietid/Southern Delta-Aquarid complex.

  15. Stream dynamics at pipeline river crossings

    SciTech Connect

    Beckstead, G.R.E.; Cavers, D.S.

    1996-12-31

    Pipeline crossings of streams, whether large or small, must consider the ability of the stream channel to scour its bed and erode its banks. Case studies are presented to illustrate the kinds of dynamic environments which must be considered in designing pipeline stream crossings. These characteristics may be determined through the use of comparative historical aerial photography and site photographs and surveys. The case studies presented as examples in this paper include gullies, bedrock-lined channels, entrenched meandering streams, multi-channel wandering streams, degrading channels, alluvial fans, and major channels affected by regulation and man-made structures. Natural hazards such as debris jams and beaver dams are also discussed. For each case study, the characteristics of the channels are described, the design approach discussed and site-specific constraints presented which affected the final design.

  16. Use of artificial streams for toxicological research

    SciTech Connect

    Shriner, C.; Gregory, T.

    1984-01-01

    A review of the literature pertaining to the use of artificial streams as research tools in both toxicant and nontoxicant studies was conducted. This document summarizes that review and provides an assessment of the value of artificial streams in toxicological research. Descriptions are presented of the major types of artificial streams including considerations for the physical design of those streams based on their intended use. Research representative of nontoxicant behavioral, productivity, and trophic relationship studies is summarized to provide a background for the more in-depth discourse on toxicant research. Toxicant research is reviewed in relation to environmental factors such as physical type of artificial stream, light, water, and substrate and experimental conditions including biota tested, method of biota introduction, measured parameters, and toxicant. Comparisons and assessment are presented concerning the use of the appropriate artificial system for addressing various types of toxicant research emphasizing simple vs. complex systems.

  17. The ecology and biogeochemistry of stream biofilms.

    PubMed

    Battin, Tom J; Besemer, Katharina; Bengtsson, Mia M; Romani, Anna M; Packmann, Aaron I

    2016-03-14

    Streams and rivers form dense networks, shape the Earth's surface and, in their sediments, provide an immensely large surface area for microbial growth. Biofilms dominate microbial life in streams and rivers, drive crucial ecosystem processes and contribute substantially to global biogeochemical fluxes. In turn, water flow and related deliveries of nutrients and organic matter to biofilms constitute major constraints on microbial life. In this Review, we describe the ecology and biogeochemistry of stream biofilms and highlight the influence of physical and ecological processes on their structure and function. Recent advances in the study of biofilm ecology may pave the way towards a mechanistic understanding of the effects of climate and environmental change on stream biofilms and the biogeochemistry of stream ecosystems. PMID:26972916

  18. An initial SPARROW model of land use and in-stream controls on total organic carbon in streams of the conterminous United States

    USGS Publications Warehouse

    Shih, Jhih-Shyang; Alexander, Richard B.; Smith, Richard A.; Boyer, Elizabeth W.; Shwarz, Grogory E.; Chung, Susie

    2010-01-01

    Watersheds play many important roles in the carbon cycle: (1) they are a site for both terrestrial and aquatic carbon dioxide (CO2) removal through photosynthesis; (2) they transport living and decomposing organic carbon in streams and groundwater; and (3) they store organic carbon for widely varying lengths of time as a function of many biogeochemical factors. Using the U.S. Geological Survey (USGS) Spatially Referenced Regression on Watershed Attributes (SPARROW) model, along with long-term monitoring data on total organic carbon (TOC), this research quantitatively estimates the sources, transport, and fate of the long-term mean annual load of TOC in streams of the conterminous United States. The model simulations use surrogate measures of the major terrestrial and aquatic sources of organic carbon to estimate the long-term mean annual load of TOC in streams. The estimated carbon sources in the model are associated with four land uses (urban, cultivated, forest, and wetlands) and autochthonous fixation of carbon (stream photosynthesis). Stream photosynthesis is determined by reach-level application of an empirical model of stream chlorophyll based on total phosphorus concentration, and a mechanistic model of photosynthetic rate based on chlorophyll, average daily solar irradiance, water column light attenuation, and reach dimensions. It was found that the estimate of in-stream photosynthesis is a major contributor to the mean annual TOC load per unit of drainage area (that is, yield) in large streams, with a median share of about 60 percent of the total mean annual carbon load in streams with mean flows above 500 cubic feet per second. The interquartile range of the model predictions of TOC from in-stream photosynthesis is from 0.1 to 0.4 grams (g) carbon (C) per square meter (m-2) per day (day-1) for the approximately 62,000 stream reaches in the continental United States, which compares favorably with the reported literature range for net carbon fixation by phytoplankton in lakes and streams. The largest contributors per unit of drainage area to the mean annual stream TOC load among the terrestrial sources are, in descending order: wetlands, urban lands, mixed forests, agricultural lands, evergreen forests, and deciduous forests . It was found that the SPARROW model estimates of TOC contributions to streams associated with these land uses are also consistent with literature estimates. SPARROW model calibration results are used to simulate the delivery of TOC loads to the coastal areas of seven major regional drainages. It was found that stream photosynthesis is the largest source of the TOC yields ( about 50 percent) delivered to the coastal waters in two of the seven regional drainages (the Pacific Northwest and Mississippi-Atchafalaya-Red River basins ), whereas terrestrial sources are dominant (greater than 60 percent) in all other regions (North Atlantic, South Atlantic-Gulf, California, Texas-Gulf, and Great Lakes).

  19. In-stream Escherichia coli Modeling

    NASA Astrophysics Data System (ADS)

    Pandey, P.; Soupir, M.

    2013-12-01

    Elevated levels of pathogenic bacteria indicators such as Escherichia coli (E. coli) in streams are a serious concern. Controlling E. coli levels in streams requires improving our existing understanding of fate and transport of E. coli at watershed scale. In-stream E. coli concentrations are potentially linked to non-point pollution sources (i.e., agricultural land). Water of a natural stream can receive E. coli by either through overland flow (via runoff from cropland) or resuspension from the streambed to the water column. Calculating in-stream total E. coli loads requires estimation of particle attached bacteria as well free floating E. coli transport. Currently water quality models commonly used for predicting E. coli levels in stream water have limited capability for predicting E. coli levels in the water column as well as in the streambed sediment. The challenges in calculating in-stream E. coli levels include difficulties in modeling the complex interactions between sediment particles and E. coli. Here we have developed a watershed scale model (integrated with Soil and Water Assessment Tool (SWAT)), which involves calculation of particle attached E. coli, to predict in-stream E. coli concentrations. The proposed model predicts E. coli levels in streambed bed sediment as well as in the water column. An extensive in-stream E. coli monitoring was carried out to verify the model predictions, and results indicate that the model performed well. The study proposed here will improve understanding on in-stream bacterial contamination, and help improving existing water quality models for predicting pathogenic bacteria levels in ambient water bodies.

  20. Unionville, Pennsylvania School's Stream Restoration Project

    NASA Astrophysics Data System (ADS)

    Madsen, S. M.

    2004-12-01

    For the past three years, students and Earth Club members of C.F. Patton Middle School and Unionville High School have been involved in a stream restoration and monitoring project along a tributary to the East Branch of the Red Clay Creek in Pennsylvania. The Red Clay is within the larger Christina River Basin watershed which drains to Delaware Bay. Total funding of \\$962.00 was awarded by the Unionville-Chadds Ford Education Foundation to purchase both stream monitoring equipment and native plant species for stream restoration. Nine science teachers in the school district received certification in stream monitoring by the Pennsylvania State Parks Division. Certification enables the science faculty and their students to enter monitoring data in a statewide stream database. The stream data includes: temperature, levels of dissolved oxygen and nutrients, pH, alkalinity, conductivity, and a complete biosurvey of invertebrates. In addition to ongoing monitoring, the Earth Club sponsored a name-the-stream contest. Quartz Creek was chosen for this previously unnamed tributary. Its' name was approved by the East Marlborough Township Supervisor in May, 2004 and was then submitted to the USGS' Board on Geographic Names. The Earth Club has also sponsored a stream restoration contest. Students in the middle school were encouraged to design a habitat along the stream banks that would keep sediment in-place, while encouraging wildlife. The stream was originally crowded with invasive multi-flora rose but this was removed with the help of parents and students over a two year period. The winning student poster was outstanding and native species were purchased and planted following the poster's design. The planting took place in May, 2004 with over 40 persons involved including 25 middle school and 8 high school students, teachers from the schools, administrators and employees of the Brandywine Conservancy, and Red Clay Valley and Brandywine Valley Associations, and graduate students from the University of Delaware.

  1. Physical Stream Habitat Dynamics in Lower Bear Creek, Northern Arkansas

    USGS Publications Warehouse

    Reuter, Joanna M.; Jacobson, Robert B.; Elliott, Caroline M.

    2003-01-01

    We evaluated the roles of geomorphic and hydrologic dynamics in determining physical stream habitat in Bear Creek, a stream with a 239 km2 drainage basin in the Ozark Plateaus (Ozarks) in northern Arkansas. During a relatively wet 12-month monitoring period, the geomorphology of Bear Creek was altered by a series of floods, including at least four floods with peak discharges exceeding a 1-year recurrence interval and another flood with an estimated 2- to 4-year recurrence interval. These floods resulted in a net erosion of sediment from the study reach at Crane Bottom at rates far in excess of other sites previously studied in the Ozarks. The riffle-pool framework of the study reach at Crane Bottom was not substantially altered by these floods, but volumes of habitat in riffles and pools changed. The 2- to 4-year flood scoured gravel from pools and deposited it in riffles, increasing the diversity of available stream habitat. In contract, the smaller floods eroded gravel from the riffles and deposited it in pools, possibly flushing fine sediment from the substrate but also decreasing habitat diversity. Channel geometry measured at the beginning of the study was use to develop a two-dimensional, finite-element hydraulic model at assess how habitat varies with hydrologic dynamics. Distributions of depth and velocity simulated over the range of discharges observed during the study (0.1 to 556 cubic meters per second, cms) were classified into habitat units based on limiting depths and Froude number criteria. The results indicate that the areas of habitats are especially sensitive to change to low to medium flows. Races (areas of swift, relatively deep water downstream from riffles) disappear completely at the lowest flows, and riffles (areas of swift, relatively shallow water) contract substantially in area. Pools also contract in area during low flow, but deep scours associated with bedrock outcrops sustain some pool area even at the lowest modeled flows. Modeled boundary shear stresses were used to evaluate which flows are responsible for the most mobilization of the bed, and therefore, habitat maintenance. Evaluation of the magnitude and frequency of bed-sediment entrainment shows that most of the habitat maintenance results from flows that occur on average about 4 to 7 days a year. Our analysis documents the geomorphic and hydrologic dynamics that form and maintain habitats in a warmwater stream in the Ozarks. The range of flows that occurs on this stream can be partitioned into those that sustain habitat by providing the combinations of depth and velocity that stream organisms live with most of the time, and those flows that surpass sediment entrainment thresholds, alter stream geomorphology, and therefore maintain habitat. The quantitative relations show sensitivity of habitats to flow variation, but do not address how flow may vary in the future, or the extent to which stream geomorphology may be affected by variations in sediment supply.

  2. Experimental investigation of acoustic streaming in a cylindrical wave guide up to high streaming Reynolds numbers.

    PubMed

    Reyt, Ida; Bailliet, Hlne; Valire, Jean-Christophe

    2014-01-01

    Measurements of streaming velocity are performed by means of Laser Doppler Velocimetry and Particle Image Velociimetry in an experimental apparatus consisting of a cylindrical waveguide having one loudspeaker at each end for high intensity sound levels. The case of high nonlinear Reynolds number ReNL is particularly investigated. The variation of axial streaming velocity with respect to the axial and to the transverse coordinates are compared to available Rayleigh streaming theory. As expected, the measured streaming velocity agrees well with the Rayleigh streaming theory for small ReNL but deviates significantly from such predictions for high ReNL. When the nonlinear Reynolds number is increased, the outer centerline axial streaming velocity gets distorted towards the acoustic velocity nodes until counter-rotating additional vortices are generated near the acoustic velocity antinodes. This kind of behavior is followed by outer streaming cells only and measurements in the near wall region show that inner streaming vortices are less affected by this substantial evolution of fast streaming pattern. Measurements of the transient evolution of streaming velocity provide an additional insight into the evolution of fast streaming. PMID:24437742

  3. Ecoregions and stream morphology in eastern Oklahoma

    NASA Astrophysics Data System (ADS)

    Splinter, Dale K.; Dauwalter, Daniel C.; Marston, Richard A.; Fisher, William L.

    2010-10-01

    Broad-scale variables (i.e., geology, topography, climate, land use, vegetation, and soils) influence channel morphology. How and to what extent the longitudinal pattern of channel morphology is influenced by broad-scale variables is important to fluvial geomorphologists and stream ecologists. In the last couple of decades, there has been an increase in the amount of interdisciplinary research between fluvial geomorphologists and stream ecologists. In a historical context, fluvial geomorphologists are more apt to use physiographic regions to distinguish broad-scale variables, while stream ecologists are more apt to use the concept of an ecosystem to address the broad-scale variables that influence stream habitat. For this reason, we designed a study using ecoregions, which uses physical and biological variables to understand how landscapes influence channel processes. Ecoregions are delineated by similarities in geology, climate, soils, land use, and potential natural vegetation. In the fluvial system, stream form and function are dictated by processes observed throughout the fluvial hierarchy. Recognizing that stream form and function should differ by ecoregion, a study was designed to evaluate how the characteristics of stream channels differed longitudinally among three ecoregions in eastern Oklahoma, USA: Boston Mountains, Ozark Highlands, and Ouachita Mountains. Channel morphology of 149 stream reaches was surveyed in 1st- through 4th-order streams, and effects of drainage area and ecoregion on channel morphology was evaluated using multiple regressions. Differences existed (? ? 0.05) among ecoregions for particle size, bankfull width, and width/depth ratio. No differences existed among ecoregions for gradient or sinuosity. Particle size was smallest in the Ozark Highlands and largest in the Ouachita Mountains. Bankfull width was larger in the Ozark Highlands than in the Boston Mountains and Ouachita Mountains in larger streams. Width/depth ratios of the Boston Mountains and Ozark Highlands were not statistically different. Significant differences existed, however, between the Boston Mountains and Ozark Highlands when compared individually to the Ouachita Mountains. We found that ecoregions afforded a good spatial structure that can help in understanding longitudinal trends in stream reach morphology surveyed at the reach scale. The hierarchy of the fluvial system begins within a broad, relatively homogenous setting that imparts control on processes that affect stream function. Ecoregions provide an adequate regional division to begin a large-scale geomorphic study of processes in stream channels.

  4. Ecoregions and stream morphology in eastern Oklahoma

    USGS Publications Warehouse

    Splinter, D.K.; Dauwalter, D.C.; Marston, R.A.; Fisher, W.L.

    2010-01-01

    Broad-scale variables (i.e., geology, topography, climate, land use, vegetation, and soils) influence channel morphology. How and to what extent the longitudinal pattern of channel morphology is influenced by broad-scale variables is important to fluvial geomorphologists and stream ecologists. In the last couple of decades, there has been an increase in the amount of interdisciplinary research between fluvial geomorphologists and stream ecologists. In a historical context, fluvial geomorphologists are more apt to use physiographic regions to distinguish broad-scale variables, while stream ecologists are more apt to use the concept of an ecosystem to address the broad-scale variables that influence stream habitat. For this reason, we designed a study using ecoregions, which uses physical and biological variables to understand how landscapes influence channel processes. Ecoregions are delineated by similarities in geology, climate, soils, land use, and potential natural vegetation. In the fluvial system, stream form and function are dictated by processes observed throughout the fluvial hierarchy. Recognizing that stream form and function should differ by ecoregion, a study was designed to evaluate how the characteristics of stream channels differed longitudinally among three ecoregions in eastern Oklahoma, USA: Boston Mountains, Ozark Highlands, and Ouachita Mountains. Channel morphology of 149 stream reaches was surveyed in 1st- through 4th-order streams, and effects of drainage area and ecoregion on channel morphology was evaluated using multiple regressions. Differences existed (?????0.05) among ecoregions for particle size, bankfull width, and width/depth ratio. No differences existed among ecoregions for gradient or sinuosity. Particle size was smallest in the Ozark Highlands and largest in the Ouachita Mountains. Bankfull width was larger in the Ozark Highlands than in the Boston Mountains and Ouachita Mountains in larger streams. Width/depth ratios of the Boston Mountains and Ozark Highlands were not statistically different. Significant differences existed, however, between the Boston Mountains and Ozark Highlands when compared individually to the Ouachita Mountains. We found that ecoregions afforded a good spatial structure that can help in understanding longitudinal trends in stream reach morphology surveyed at the reach scale. The hierarchy of the fluvial system begins within a broad, relatively homogenous setting that imparts control on processes that affect stream function. Ecoregions provide an adequate regional division to begin a large-scale geomorphic study of processes in stream channels. ?? 2010 Elsevier B.V.

  5. Evaluating the reliability of the stream tracer approach to characterize stream-subsurface water exchange

    USGS Publications Warehouse

    Harvey, J.W.; Wagner, B.J.; Bencala, K.E.

    1996-01-01

    Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub- reach-scale measurement of hydraulic heads and hydraulic conductivity to compute streambed fluxes (hydrometric approach) and reachscale modeling of in- stream solute tracer injections to determine characteristic length and timescales of exchange with storage zones (stream tracer approach). Subsurface data were the standard of comparison used to evaluate the reliability of the stream tracer approach to characterize hyporheic exchange. The reach-averaged hyporheic exchange flux (1.5 mL s-1 m-1), determined by hydrometric methods, was largest when stream base flow was low (10 L s-1); hyporheic exchange persisted when base flow was 10- fold higher, decreasing by approximately 30%. Reliability of the stream tracer approach to detect hyporheic exchange was assessed using first- order uncertainty analysis that considered model parameter sensitivity. The stream tracer approach did not reliably characterize hyporheic exchange at high base flow: the model was apparently more sensitive to exchange with surface water storage zones than with the hyporheic zone. At low base flow the stream tracer approach reliably characterized exchange between the stream and gravel streambed (timescale of hours) but was relatively insensitive to slower exchange with deeper alluvium (timescale of tens of hours) that was detected by subsurface measurements. The stream tracer approach was therefore not equally sensitive to all timescales of hyporheic exchange. We conclude that while the stream tracer approach is an efficient means to characterize surface-subsurface exchange, future studies will need to more routinely consider decreasing sensitivities of tracer methods at higher base flow and a potential bias toward characterizing only a fast component of hyporheic exchange. Stream tracer models with multiple rate constants to consider both fast exchange with streambed gravel and slower exchange with deeper alluvium appear to be warranted.

  6. Mixing augmentation of supersonic streams

    NASA Astrophysics Data System (ADS)

    Hari, S.; Kurian, J.

    2001-10-01

    The use of passive mixing devices to enhance the mixing of supersonic streams is of importance in many aerospace and allied applications. A comparative experimental study of two such non-conventional axisymmetric supersonic nozzles for mixing augmentation is undertaken in the present study. The nozzles studied are conventional convergent divergent (c-d), ramp, and nozzle with secondary tabs at the Mach number of 1.7. The freejet characteristics of the jets from the nozzles and the confined mixing of the jets under isothermal and non-isothermal conditions were experimentally investigated. In addition, schlieren and laser light sheet methods are employed for flow visualization. Results of experiments on freejet showed rapid total pressure decay, higher jet width, and increased shear layer width in the case of jets from non-conventional nozzles. Also visualized were complex shock patterns in these jets. The confined mixing studies in both cold and hot flows confirm the increased mixing behavior of non-conventional nozzles within shorter mixing duct lengths. Laser sheet visualization clearly demonstrated the formation of streamwise vortices, which accounts for the enhanced mixing while employing the nozzles under study.

  7. Prediction of stream volatilization coefficients

    USGS Publications Warehouse

    Rathbun, Ronald E.

    1990-01-01

    Equations are developed for predicting the liquid-film and gas-film reference-substance parameters for quantifying volatilization of organic solutes from streams. Molecular weight and molecular-diffusion coefficients of the solute are used as correlating parameters. Equations for predicting molecular-diffusion coefficients of organic solutes in water and air are developed, with molecular weight and molal volume as parameters. Mean absolute errors of prediction for diffusion coefficients in water are 9.97% for the molecular-weight equation, 6.45% for the molal-volume equation. The mean absolute error for the diffusion coefficient in air is 5.79% for the molal-volume equation. Molecular weight is not a satisfactory correlating parameter for diffusion in air because two equations are necessary to describe the values in the data set. The best predictive equation for the liquid-film reference-substance parameter has a mean absolute error of 5.74%, with molal volume as the correlating parameter. The best equation for the gas-film parameter has a mean absolute error of 7.80%, with molecular weight as the correlating parameter.

  8. Photocontrolled living polymerizations

    NASA Astrophysics Data System (ADS)

    Tanabe, Makoto; Vandermeulen, Guido W. M.; Chan, Wing Yan; Cyr, Paul W.; Vanderark, Lawrence; Rider, David A.; Manners, Ian

    2006-06-01

    Living polymerizations involve the creation of polymer chains without significant irreversible chain transfer or chain termination. Such processes are widely used to access well-defined macromolecular materials with controlled architectures, such as block and star polymers. Although this concept was first realized for anionic polymerizations in the 1950s, many key recent advances have been made, most notably in the area of radical polymerization. Here, we report a living photopolymerization that involves photoexcited monomers. Exposure of metal-containing ferrocenophane monomers to Pyrex-filtered light from a mercury lamp (?>310 nm) or to bright sunlight in the presence of an anionic initiator leads to living polymerizations, in which the conversion and molecular weight of the resulting polymer can be controlled by the irradiation time. Photoirradiation selectively weakens the iron-cyclopentadienyl bond in the monomer, allowing the use of moderately basic and highly functional-group-tolerant initiators. The polymerization proceeds through attack of the initiator and propagating anion on the iron atom of the photoexcited monomer and, remarkably, the polymerization rate decreases with increasing temperature. Block copolymer formation is possible when the light source is alternately switched on and off in between sequential addition of different monomers, providing unprecedented, photocontrolled access to new types of functional polymers.

  9. Families and Assisted Living*

    PubMed Central

    Gaugler, Joseph E.; Kane, Robert L.

    2008-01-01

    Purpose Despite growing research on assisted living (AL) as a residential care option for older adults, the social ramifications of residents' transitions to assisted living is relatively unexplored. This article examines family involvement in AL, including family structures of residents, types of involvement from family members living outside the AL, and outcomes for these family members. Design and Methods We reviewed current literature utilizing the MEDLINE, PSYCINFO, and CINAHL databases to identify AL studies that examined issues pertaining to families or informal care. Following the screening of abstracts, 180 reports were retrieved for further review, and 62 studies were selected for inclusion. Results Families visit residents frequently and provide a wide range of instrumental assistance but provide only minimal personal care. Studies of family outcomes indicated relatively high satisfaction, but potential care burden as well. Implications How family care and involvement occurs in AL in relation to formal care provision and whether various types of formal-informal care integration influence family outcomes remains unclear. We suggest a research agenda that attempts to tease out causal relationships for family involvement, differentiate family roles, and implement longitudinal analyses for a range of family outcomes. PMID:18162571

  10. Assessment for Active Living

    PubMed Central

    Bors, Philip A.; Brownson, Ross C.; Brennan, Laura K.

    2016-01-01

    Background Robert Wood Johnson Foundations Active Living by Design (ALbD) grant program funded 25 communities across the U.S. The ALbD National Program Office (NPO) supported grantee community partnerships with technical assistance for assessment, planning, and implementation activities intended to increase population levels of physical activity. Purpose This paper analyzes and summarizes the range of assessments conducted to identify local barriers and opportunities for active living as important elements of a thorough intervention planning process. Methods Evaluation of the partnerships focused on documenting community changes and strategies used to produce those changes. With support from NPO staff and external evaluators, partnerships tracked and summarized their community assessment approaches as well as strengths and challenges in conducting assessments. Results The partnerships documented a range of assessment strategies and methods. Partnerships conducted several qualitative methods including focus groups, individual and group interviews, and public meetings. Quantitative methods included surveys, audits, observations, and analysis of existing data, among others. The environmental audit was the most common assessment method used by the partnerships. Assessment processes and findings were used for not only intervention planning but also community engagement and direct advocacy. Assessment data collectors varied from professional staff to community volunteers. Conclusions Assessments were essential to the identification of local barriers and assets related to active living, which in turn helped ALbD partnerships prioritize and refine their action strategies. Assessment processes were also valuable in building relationships with new partners, community members, and local officials. PMID:23079262

  11. RELATING WEIGHT AND COUNT DISTRIBUTIONS OF STREAM BED GRAVEL

    EPA Science Inventory

    The size distribution of particles in a stream bed reflects the stream hydrology as well as its physical and chemical water quality characteristics. In environmental assessments, gravel distribution determines habitat quality for aquatic insects and stream suitability for spawnin...

  12. Dynamics of stream-subhalo interactions

    NASA Astrophysics Data System (ADS)

    Sanders, Jason L.; Bovy, Jo; Erkal, Denis

    2016-01-01

    We develop a formalism for modelling the impact of dark matter subhaloes on cold thin streams. Our formalism models the formation of a gap in a stream in angle-frequency space and is able to handle general stream and impact geometry. We analyse an N-body simulation of a cold stream formed from a progenitor on an eccentric orbit in an axisymmetric potential, which is perturbed by a direct impact from a 108M? subhalo, and produce a complete generative model of the perturbed stream that matches the simulation well at a range of times. We show how the results in angle-frequency space can be related to physical properties of the gaps and that previous results for more constrained simulations are recovered. We demonstrate how our results are dependent upon the mass of the subhalo and the location of the impact along the stream. We find that gaps formed far downstream grow more rapidly than those closer to the progenitor due to the more ordered nature of the stream members far from the progenitor. Additionally, we show that the minimum gap density plateaus in time at a value that decreases with increasing subhalo mass.

  13. Ecological health in the Nation's streams

    USGS Publications Warehouse

    Carlisle, Daren M.; Woodside, Michael D.

    2013-01-01

    Aquatic biological communities, which are collections of organisms, are a direct measure of stream health because they indicate the ability of a stream to support life. This fact sheet highlights selected findings of a national assessment of stream health by the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The assessment was unique in that it integrated the condition of three biological communities—algae, macroinvertebrates, and fish—as well as measures of streamflow modification, pesticides, nutrients, and other factors. At least one biological community was altered at 83 percent of assessed streams, and the occurrence of altered communities was highest in urban streams. Streamflows were modified at 86 percent of assessed streams, and increasing severity of streamflow modification was associated with increased occurrence of altered biological communities. Agricultural and urban land use in watersheds may contribute pesticides and nutrients to stream waters, and increasing concentrations of these chemicals were associated with increased occurrence of altered biological communities.

  14. Dynamics of stream-subhalo interactions

    NASA Astrophysics Data System (ADS)

    Sanders, Jason L.; Bovy, Jo; Erkal, Denis

    2016-04-01

    We develop a formalism for modelling the impact of dark matter subhaloes on cold thin streams. Our formalism models the formation of a gap in a stream in angle-frequency space and is able to handle general stream and impact geometry. We analyse an N-body simulation of a cold stream formed from a progenitor on an eccentric orbit in an axisymmetric potential, which is perturbed by a direct impact from a 108 M⊙ subhalo, and produce a complete generative model of the perturbed stream that matches the simulation well at a range of times. We show how the results in angle-frequency space can be related to physical properties of the gaps and that previous results for more constrained simulations are recovered. We demonstrate how our results are dependent upon the mass of the subhalo and the location of the impact along the stream. We find that gaps formed far downstream grow more rapidly than those closer to the progenitor due to the more ordered nature of the stream members far from the progenitor. Additionally, we show that the minimum gap density plateaus in time at a value that decreases with increasing subhalo mass.

  15. Charting the trajectory of the ATLAS stream

    NASA Astrophysics Data System (ADS)

    de Boer, Thomas; Belokurov, Vasily; Koposov, Sergey; Irwin, Mike; Erkal, Denis

    2014-08-01

    Stellar streams provide dramatic confirmation that large systems accrete smaller systems, in the context of a hierarchical merging cosmology, and therefore contain important clues about the formation mechanism of the Galactic halo. By studying the detailed properties of streams we can determine how stars are stripped from their hosts due to the Galactic tidal field and how the formation of the Galactic halo may have proceeded. Here we propose to trace the full visible extent of the recently discovered ATLAS stream using deep, wide-field photometry, to determine its path across the sky in 3 dimensions. By utilising the very wide-field capabilities of DECam, we will determine the deep, MW decontaminated CMD in a 30 degree long portion of the stream, allowing us to determine the distance, density profile and stellar population makeup of the stream. The position and density on the sky of kinematically cold structures like the ATLAS stream provides powerful, unbiased constraints on the distribution of dark matter in the Galaxy. Furthermore, deep photometry of the stellar content of the stream will tell us what type of system was the likely progenitor: globular cluster, ultra-faint dwarf or dSph galaxy.

  16. REGIONAL METHODS INITIATIVE: DEVELOPMENT OF BIOLOGICAL INDICATORS, METHODS AND ASSESSMENT TECHNIQUES IN FIRST ORDER AND INTERMITTENT STREAMS: HEADWATER INTERMITTENT STREAMS STUDY

    EPA Science Inventory

    Headwater streams represent the majority of streams and stream miles within many stream networks. Because headwater streams represent the interface between surrounding land use and downstream waterbodies, there has been a growing interest in monitoring the condition of headwater...

  17. The Role of Ice Streams in Deglaciation

    NASA Astrophysics Data System (ADS)

    Robel, A.; Schoof, C.; Tziperman, E.

    2014-12-01

    Ice streams are regions of fast flow within ice sheets that can exhibit variability on time scales ranging from years to millennia. Observations and model reconstructions indicate that ice streams likely played a major role in the most recent deglaciation of the Laurentide Ice Sheet. The variability of these ice streams may have dictated the spatiotemporal progression of deglaciation, as some ice sheet domes may have been more sensitive to dynamic changes in ice stream activity. We analyze the behavior of both idealized and realistic ice sheet configurations to determine the role of ice streams in setting ice sheet steady states and the spatiotemporal sequence of deglacial transitions. We also examine the way in which climate feedbacks could have amplified the response of ice streams to Milankovitch forcing, thereby initiating ice sheet collapse. We use the Parallel Ice Sheet Model (PISM), by itself and coupled to an energy balance atmospheric model. The presence of ice streams dramatically alters steady-state ice sheet configurations, allowing for the existence of thin, widely extended margins. There is a marked transition from binge-purge-like ice stream variability (that is believed to have occurred as part of Heinrich events during the last glacial period) to steady ice stream flow as climate (temperature, precipitation) is varied over a range corresponding to glacial variability. This qualitative transition in ice sheet dynamics amplifies small changes in external forcing (e.g. Milankovitch cycles) sufficiently to activate strong climate feedbacks. We discuss how the reorganization of ice sheet configuration, through changes in ice sheet extent and elevation, may favor certain climate feedbacks (e.g. ice-albedo and lapse rate feedbacks). We also relate these analyses to observations of Laurentide deglaciation and discuss implications for the future of the Greenland and Antarctic Ice Sheets.

  18. Fast algorithm for automatically computing Strahler stream order

    USGS Publications Warehouse

    Lanfear, Kenneth J.

    1990-01-01

    An efficient algorithm was developed to determine Strahler stream order for segments of stream networks represented in a Geographic Information System (GIS). The algorithm correctly assigns Strahler stream order in topologically complex situations such as braided streams and multiple drainage outlets. Execution time varies nearly linearly with the number of stream segments in the network. This technique is expected to be particularly useful for studying the topology of dense stream networks derived from digital elevation model data.

  19. Herbicides in streams. Midwestern United States

    USGS Publications Warehouse

    Goolsby, Donald A.; Thurman, E. Michael; Kolpin, Dana W.

    1991-01-01

    Results from a 2-year study of 149 streams geographically distributed across the corn-producing region of 10 midwestern States show that detectable concentrations of herbicides persist year round in most streams. Some herbicides exceeded proposed maximum contaminant levels for drinking water for periods of several weeks to several months following application. Atrazine was the most frequently detected and most persistent herbicide measured, followed by desethylatrazine and metolachlor. The seasonal distribution of atrazine indicates that aquifers contributing base flow to many of the streams are contaminated with herbicides.

  20. Events and Trends in Text Streams

    SciTech Connect

    Engel, David W.; Whitney, Paul D.; Cramer, Nicholas O.

    2010-03-04

    "Text streams--collections of documents or messages that are generated and observed over time--are ubiquitous. Our research and development are targeted at developing algorithms to find and characterize changes in topic within text streams. To date, this research has demonstrated the ability to detect and describe 1) short duration, atypical events and 2) the emergence of longer-term shifts in topical content. This technology has been applied to predefined temporally ordered document collections but is also suitable for application to near-real-time textual data streams."

  1. Methods of separating particulate residue streams

    DOEpatents

    Hoskinson, Reed L. (Rigby, ID); Kenney, Kevin L. (Idaho Falls, ID); Wright, Christopher T. (Idaho Falls, ID); Hess, J. Richard (Idaho Falls, ID)

    2011-04-05

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  2. Object-based media and stream-based computing

    NASA Astrophysics Data System (ADS)

    Bove, V. Michael, Jr.

    1998-03-01

    Object-based media refers to the representation of audiovisual information as a collection of objects - the result of scene-analysis algorithms - and a script describing how they are to be rendered for display. Such multimedia presentations can adapt to viewing circumstances as well as to viewer preferences and behavior, and can provide a richer link between content creator and consumer. With faster networks and processors, such ideas become applicable to live interpersonal communications as well, creating a more natural and productive alternative to traditional videoconferencing. In this paper is outlined an example of object-based media algorithms and applications developed by my group, and present new hardware architectures and software methods that we have developed to enable meeting the computational requirements of object- based and other advanced media representations. In particular we describe stream-based processing, which enables automatic run-time parallelization of multidimensional signal processing tasks even given heterogenous computational resources.

  3. Woody Debris: Linking Stream Morphology and Aquatic Biota in Southeastern Coastal Plain Streams, USA

    NASA Astrophysics Data System (ADS)

    Thom, T. A.; Herod, J. J.

    2005-05-01

    In-stream habitat including woody debris is widely recognized as an important aspect of aquatic health. Relationships between woody debris and the distribution and life history of aquatic species are increasingly documented in the literature. In southeastern coastal plain streams, woody debris may have a greater influence on stream form and function than in other regions due to highly mobile shifting sand substrates. In an effort to document baseline stream conditions, natural variability within biological communities, and to also link chemical, physical and biological parameters within the Gulf Coastal Plain physiographic region, aquatic surveys have been conducted on Eglin Air Force Base, Florida over the past four years. We developed quantitative indicators of habitat health and protocols for measuring habitat condition at various geographic scales. Physical variables included stream channel characteristics, habitat connectivity, riparian cover and in-stream habitat including woody debris. Biological data (fishes and aquatic insects) were compared with in-stream habitat data for 56 sites. Significant relationships between species and in-stream habitat presence/absence and abundance were detected. Associations between woody debris and bed morphology were also significant. These preliminary data suggest that woody debris is an important factor shaping biological communities and stream geomorphic features in sand-bottom coastal plain streams.

  4. Time-Based Data Streams: Fundamental Concepts for a Data Resource for Streams

    SciTech Connect

    Beth A. Plale

    2009-10-10

    Real time data, which we call data streams, are readings from instruments, environmental, bodily or building sensors that are generated at regular intervals and often, due to their volume, need to be processed in real time. Often a single pass is all that can be made on the data, and a decision to discard or keep the instance is made on the spot. Too, the stream is for all practical purposes indefinite, so decisions must be made on incomplete knowledge. This notion of data streams has a different set of issues from a file, for instance, that is byte streamed to a reader. The file is finite, so the byte stream is becomes a processing convenience more than a fundamentally different kind of data. Through the duration of the project we examined three aspects of streaming data: the first, techniques to handle streaming data in a distributed system organized as a collection of web services, the second, the notion of the dashboard and real time controllable analysis constructs in the context of the Fermi Tevatron Beam Position Monitor, and third and finally, we examined provenance collection of stream processing such as might occur as raw observational data flows from the source and undergoes correction, cleaning, and quality control. The impact of this work is severalfold. We were one of the first to advocate that streams had little value unless aggregated, and that notion is now gaining general acceptance. We were one of the first groups to grapple with the notion of provenance of stream data also.

  5. A Stellar Stream Surrounds the Whale Galaxy

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-10-01

    The -cold dark matter cosmological model predicts that galaxies are assembled through the disruption and absorption of small satellite dwarf galaxies by their larger hosts. A recent study argues that NGC 4631, otherwise known as the Whale galaxy, shows evidence of such a recent merger in the form of an enormous stellar stream extending from it.Stream SignaturesAccording to the -CDM model, stellar tidal streams should be a ubiquitous feature among galaxies. When satellite dwarf galaxies are torn apart, they spread out into such streams before ultimately feeding the host galaxy. Unfortunately, these streams are very faint, so were only recently starting to detect these features.Stellar tidal streams have been discovered around the Milky Way and Andromeda, providing evidence of these galaxies growth via recent (within the last 8 Gyr) mergers. But discovering stellar streams around other Milky Way-like galaxies would help us to determine if the model of hierarchical galaxy assembly applies generally.To this end, the Stellar Tidal Stream Survey, led by PI David Martnez-Delgado (Center for Astronomy of Heidelberg University), is carrying out the first systematic survey of stellar tidal streams. In a recent study, Martnez-Delgado and collaborators present their detection of a giant (85 kpc long!) stellar tidal stream extending into the halo of NGC 4631, the Whale galaxy.Modeling a SatelliteThe top image is a snapshot from an N-body simulation of a single dwarf satellite, 3.5 Gyr after it started interacting with the Whale galaxy. The satellite has been torn apart and spread into a stream that reproduces observations, which are shown in the lower image (scale is not the same). [Martnez-Delgado et al. 2015]The Whale galaxy is a nearby edge-on spiral galaxy interacting with a second spiral, NGC 4656. But the authors dont believe that the Whale galaxys giant tidal stellar stream is caused by its interactions with NGC 4656. Instead, based on their observations, they believe that a dwarf satellite galaxy was disrupted to make that stream.To support their observations, the authors modeled the system using an N-body simulation. They were able to reproduce the appearance of the stream by sending a single, massive dwarf satellite onto a moderately eccentric orbit around the Whale galaxy. The team showed that, over the span of about 3.5 Gyr, the satellite became disrupted and spread into a structure very similar to the stellar tidal stream we now observe. In this simulation, the last remains of the dwarf satellite are contained within the northwest arm of the stream.The authors point out that the Whale galaxy has additional gaseous tidal features that likely originated from a more recent, gas-rich accretion event. There are also two bright regions that may be more dwarf satellites around the galaxy (labeled DW1 and DW2 in the header image). If the authors interpretation of the observed stellar stream is correct, then the Whale galaxy shows evidence for multiple recent mergers. This would support the idea that hierarchical formation models apply to other galaxies similar to the Milky Way.CitationDavid Martnez-Delgado et al 2015 AJ 150 116. doi:10.1088/0004-6256/150/4/116

  6. A Stellar Stream Surrounds the Whale Galaxy

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    The -cold dark matter cosmological model predicts that galaxies are assembled through the disruption and absorption of small satellite dwarf galaxies by their larger hosts. A recent study argues that NGC 4631, otherwise known as the Whale galaxy, shows evidence of such a recent merger in the form of an enormous stellar stream extending from it.Stream SignaturesAccording to the -CDM model, stellar tidal streams should be a ubiquitous feature among galaxies. When satellite dwarf galaxies are torn apart, they spread out into such streams before ultimately feeding the host galaxy. Unfortunately, these streams are very faint, so were only recently starting to detect these features.Stellar tidal streams have been discovered around the Milky Way and Andromeda, providing evidence of these galaxies growth via recent (within the last 8 Gyr) mergers. But discovering stellar streams around other Milky Way-like galaxies would help us to determine if the model of hierarchical galaxy assembly applies generally.To this end, the Stellar Tidal Stream Survey, led by PI David Martnez-Delgado (Center for Astronomy of Heidelberg University), is carrying out the first systematic survey of stellar tidal streams. In a recent study, Martnez-Delgado and collaborators present their detection of a giant (85 kpc long!) stellar tidal stream extending into the halo of NGC 4631, the Whale galaxy.Modeling a SatelliteThe top image is a snapshot from an N-body simulation of a single dwarf satellite, 3.5 Gyr after it started interacting with the Whale galaxy. The satellite has been torn apart and spread into a stream that reproduces observations, which are shown in the lower image (scale is not the same). [Martnez-Delgado et al. 2015]The Whale galaxy is a nearby edge-on spiral galaxy interacting with a second spiral, NGC 4656. But the authors dont believe that the Whale galaxys giant tidal stellar stream is caused by its interactions with NGC 4656. Instead, based on their observations, they believe that a dwarf satellite galaxy was disrupted to make that stream.To support their observations, the authors modeled the system using an N-body simulation. They were able to reproduce the appearance of the stream by sending a single, massive dwarf satellite onto a moderately eccentric orbit around the Whale galaxy. The team showed that, over the span of about 3.5 Gyr, the satellite became disrupted and spread into a structure very similar to the stellar tidal stream we now observe. In this simulation, the last remains of the dwarf satellite are contained within the northwest arm of the stream.The authors point out that the Whale galaxy has additional gaseous tidal features that likely originated from a more recent, gas-rich accretion event. There are also two bright regions that may be more dwarf satellites around the galaxy (labeled DW1 and DW2 in the header image). If the authors interpretation of the observed stellar stream is correct, then the Whale galaxy shows evidence for multiple recent mergers. This would support the idea that hierarchical formation models apply to other galaxies similar to the Milky Way.CitationDavid Martnez-Delgado et al 2015 AJ 150 116. doi:10.1088/0004-6256/150/4/116

  7. Community Living Skills Guide: Homemaking and Family Living.

    ERIC Educational Resources Information Center

    Jones, Gwen; Kreps, Alice Roelofs

    This is one of twenty course guides in the Community Living Skills Guide for the College for Living series which provides guidelines and workbook activities for the course, Homemaking and Family Living. The series of courses for developmentally disabled adults is intended to supplement residential programs and to aid in orienting institutionalized

  8. More of the same: high functional redundancy in stream fish assemblages from tropical agroecosystems.

    PubMed

    Casatti, Lilian; Teresa, Fabrício Barreto; Zeni, Jaquelini de Oliveira; Ribeiro, Mariela Domiciano; Brejão, Gabriel Lourenço; Ceneviva-Bastos, Mônica

    2015-06-01

    In this study, we investigated the influence of environmental variables (predictor variables) on the species richness, species diversity, functional diversity, and functional redundancy (response variables) of stream fish assemblages in an agroecosystem that harbor a gradient of degradation. We hypothesized that, despite presenting high richness or diversity in some occasions, fish communities will be more functionally redundant with stream degradation. Species richness, species diversity, and functional redundancy were predicted by the percentage of grass on the banks, which is a characteristic that indicates degraded conditions, whereas the percentage of coarse substrate in the stream bottom was an important predictor of all response variables and indicates more preserved conditions. Despite being more numerous and diverse, the groups of species living in streams with an abundance of grass on the banks perform similar functions in the ecosystem. We found that riparian and watershed land use had low predictive power in comparison to the instream habitat. If there is any interest in promoting ecosystem functions and fish diversity, conservation strategies should seek to restore forests in watersheds and riparian buffers, protect instream habitats from siltation, provide wood debris, and mitigate the proliferation of grass on stream banks. Such actions will work better if they are planned together with good farming practices because these basins will continue to be used for agriculture and livestock in the future. PMID:25822887

  9. More of the Same: High Functional Redundancy in Stream Fish Assemblages from Tropical Agroecosystems

    NASA Astrophysics Data System (ADS)

    Casatti, Lilian; Teresa, Fabrício Barreto; Zeni, Jaquelini de Oliveira; Ribeiro, Mariela Domiciano; Brejão, Gabriel Lourenço; Ceneviva-Bastos, Mônica

    2015-06-01

    In this study, we investigated the influence of environmental variables (predictor variables) on the species richness, species diversity, functional diversity, and functional redundancy (response variables) of stream fish assemblages in an agroecosystem that harbor a gradient of degradation. We hypothesized that, despite presenting high richness or diversity in some occasions, fish communities will be more functionally redundant with stream degradation. Species richness, species diversity, and functional redundancy were predicted by the percentage of grass on the banks, which is a characteristic that indicates degraded conditions, whereas the percentage of coarse substrate in the stream bottom was an important predictor of all response variables and indicates more preserved conditions. Despite being more numerous and diverse, the groups of species living in streams with an abundance of grass on the banks perform similar functions in the ecosystem. We found that riparian and watershed land use had low predictive power in comparison to the instream habitat. If there is any interest in promoting ecosystem functions and fish diversity, conservation strategies should seek to restore forests in watersheds and riparian buffers, protect instream habitats from siltation, provide wood debris, and mitigate the proliferation of grass on stream banks. Such actions will work better if they are planned together with good farming practices because these basins will continue to be used for agriculture and livestock in the future.

  10. Cooperation stimulation strategies for peer-to-peer wireless live video-sharing social networks.

    PubMed

    Lin, W Sabrina; Zhao, H Vicky; Liu, K J Ray

    2010-07-01

    Human behavior analysis in video sharing social networks is an emerging research area, which analyzes the behavior of users who share multimedia content and investigates the impact of human dynamics on video sharing systems. Users watching live streaming in the same wireless network share the same limited bandwidth of backbone connection to the Internet, thus, they might want to cooperate with each other to obtain better video quality. These users form a wireless live-streaming social network. Every user wishes to watch video with high quality while paying as little as possible cost to help others. This paper focuses on providing incentives for user cooperation. We propose a game-theoretic framework to model user behavior and to analyze the optimal strategies for user cooperation simulation in wireless live streaming. We first analyze the Pareto optimality and the time-sensitive bargaining equilibrium of the two-person game. We then extend the solution to the multiuser scenario. We also consider potential selfish users' cheating behavior and malicious users' attacking behavior and analyze the performance of the proposed strategies with the existence of cheating users and malicious attackers. Both our analytical and simulation results show that the proposed strategies can effectively stimulate user cooperation, achieve cheat free and attack resistance, and help provide reliable services for wireless live streaming applications. PMID:20227979

  11. Combining Live Video and Audio Broadcasting, Synchronous Chat, and Asynchronous Open Forum Discussions in Distance Education

    ERIC Educational Resources Information Center

    Teng, Tian-Lih; Taveras, Marypat

    2004-01-01

    This article outlines the evolution of a unique distance education program that began as a hybrid--combining face-to-face instruction with asynchronous online teaching--and evolved to become an innovative combination of synchronous education using live streaming video, audio, and chat over the Internet, blended with asynchronous online discussions

  12. Riparian and in-stream controls on nutrient concentrations and fluxes in a headwater forested stream

    NASA Astrophysics Data System (ADS)

    Bernal, S.; Lupon, A.; Ribot, M.; Sabater, F.; Mart, E.

    2015-03-01

    Headwater streams are recipients of water sources draining through terrestrial ecosystems. At the same time, stream biota can transform and retain nutrients dissolved in stream water. Yet studies considering simultaneously these two sources of variation in stream nutrient chemistry are rare. To fill this gap of knowledge, we analyzed stream water and riparian groundwater concentrations and fluxes as well as in-stream net uptake rates for nitrate (NO3-), ammonium (NH4+), and soluble reactive phosphorus (SRP) along a 3.7 km reach on an annual basis. Chloride concentrations (used as conservative tracer) indicated a strong hydrological connection at the riparian-stream interface. However, stream and riparian groundwater nutrient concentrations showed a moderate to null correlation, suggesting high in-stream biogeochemical processing. In-stream net nutrient uptake (Fsw) was highly variable across contiguous segments and over time, but its temporal variation was not related to the vegetative period of the riparian forest. For NH4+, the occurrence of Fsw > 0 ?g N m-1 s-1 (gross uptake > release) was high along the reach, while for NO3-, the occurrence of Fsw < 0 ?g N m-1 s-1 (gross uptake < release) increased along the reach. Within segments and dates, Fsw, whether negative or positive, accounted for a median of 6, 18, and 20% of the inputs of NO3-, NH4+, and SRP, respectively. Whole-reach mass balance calculations indicated that in-stream net uptake reduced stream NH4+ flux up to 90%, while the stream acted mostly as a source of NO3- and SRP. During the dormant period, concentrations decreased along the reach for NO3-, but increased for NH4+ and SRP. During the vegetative period, NH4+ decreased, SRP increased, and NO3- showed a U-shaped pattern along the reach. These longitudinal trends resulted from the combination of hydrological mixing with terrestrial inputs and in-stream nutrient processing. Therefore, the assessment of these two sources of variation in stream water chemistry is crucial to understand the contribution of in-stream processes to stream nutrient dynamics at relevant ecological scales.

  13. Live from the Arctic

    NASA Astrophysics Data System (ADS)

    Warnick, W. K.; Haines-Stiles, G.; Warburton, J.; Sunwood, K.

    2003-12-01

    For reasons of geography and geophysics, the poles of our planet, the Arctic and Antarctica, are places where climate change appears first: they are global canaries in the mine shaft. But while Antarctica (its penguins and ozone hole, for example) has been relatively well-documented in recent books, TV programs and journalism, the far North has received somewhat less attention. This project builds on and advances what has been done to date to share the people, places, and stories of the North with all Americans through multiple media, over several years. In a collaborative project between the Arctic Research Consortium of the United States (ARCUS) and PASSPORT TO KNOWLEDGE, Live from the Arctic will bring the Arctic environment to the public through a series of primetime broadcasts, live and taped programming, interactive virtual field trips, and webcasts. The five-year project will culminate during the 2007-2008 International Polar Year (IPY). Live from the Arctic will: A. Promote global understanding about the value and world -wide significance of the Arctic, B. Bring cutting-edge research to both non-formal and formal education communities, C. Provide opportunities for collaboration between arctic scientists, arctic communities, and the general public. Content will focus on the following four themes. 1. Pan-Arctic Changes and Impacts on Land (i.e. snow cover; permafrost; glaciers; hydrology; species composition, distribution, and abundance; subsistence harvesting) 2. Pan-Arctic Changes and Impacts in the Sea (i.e. salinity, temperature, currents, nutrients, sea ice, marine ecosystems (including people, marine mammals and fisheries) 3. Pan-Arctic Changes and Impacts in the Atmosphere (i.e. precipitation and evaporation; effects on humans and their communities) 4. Global Perspectives (i.e. effects on humans and communities, impacts to rest of the world) In The Earth is Faster Now, a recent collection of comments by members of indigenous arctic peoples, arctic residents speak in eloquent terms of the changes they see around them, manifested in new patterns of vegetation, the melting of permafrost and the absence of game species that used to be abundant. Meanwhile, new satellites and more sophisticated sensors on the ground and in the ice, add scientific testimony that seems to support and even extend native perceptions. Live from the Arctic will unify both perspectives, and use todays most powerful and effective communications media to connect young people and general audiences all across America to researchers and communities living and working in the Arctic. During IPY there will be a level of interest in the Polar regions unprecedented in a generation. Live from the Arctic offers unique resources to satisfy that curiosity, and encourage active participation and engagement in understanding some of Earths most significant peoples, places and rapidly changing conditions.

  14. Marine-derived nutrients, bioturbation, and ecosystem metabolism: reconsidering the role of salmon in streams.

    PubMed

    Holtgrieve, Gordon W; Schindler, Daniel E

    2011-02-01

    In coastal areas of the North Pacific Ocean, annual returns of spawning salmon provide a substantial influx of nutrients and organic matter to streams and are generally believed to enhance the productivity of recipient ecosystems. Loss of this subsidy from areas with diminished salmon runs has been hypothesized to limit ecosystem productivity in juvenile salmon rearing habitats (lakes and streams), thereby reinforcing population declines. Using five to seven years of data from an Alaskan stream supporting moderate salmon densities, we show that salmon predictably increased stream water nutrient concentrations, which were on average 190% (nitrogen) and 390% (phosphorus) pre-salmon values, and that primary producers incorporated some of these nutrients into tissues. However, benthic algal biomass declined by an order of magnitude despite increased nutrients. We also measured changes in stream ecosystem metabolic properties, including gross primary productivity (GPP) and ecosystem respiration (ER), from three salmon streams by analyzing diel measurements of oxygen concentrations and stable isotopic ratios (delta O-O2) within a Bayesian statistical model of oxygen dynamics. Our results do not support a shift toward higher primary productivity with the return of salmon, as is expected from a nutrient fertilization mechanism. Rather, net ecosystem metabolism switched from approximately net autotrophic (GPP > or = ER) to a strongly net heterotrophic state (GPP < ER) in response to bioturbation of benthic habitats by salmon. Following the seasonal arrival of salmon, GPP declined to <12% of pre-salmon rates, while ER increased by over threefold. Metabolism by live salmon could not account for the observed increase in ER early in the salmon run, suggesting salmon nutrients and disturbance enhanced in situ heterotrophic respiration. Salmon also changed the physical properties of the stream, increasing air-water gas exchange by nearly 10-fold during peak spawning. We suggest that management efforts to restore salmon ecosystems should consider effects on ecosystem metabolic properties and how salmon disturbance affects the incorporation of marine-derived nutrients into food webs. PMID:21618917

  15. Biological Conditions in Streams of Johnson County, Kansas, and Nearby Missouri, 2003 and 2004

    USGS Publications Warehouse

    Poulton, Barry C.; Rasmussen, Teresa J.; Lee, Casey J.

    2007-01-01

    Johnson County is one of the fastest growing and most populated counties in Kansas. Urban development affects streams by altering stream hydrology, geomorphology, water chemistry, and habitat, which then can lead to adverse effects on fish and macroinvertebrate communities. In addition, increasing sources of contaminants in urbanizing streams results in public-health concerns associated with exposure to and consumption of contaminated water. Biological assessments, or surveys of organisms living in aquatic environments, are crucial components of water-quality programs because they provide an indication of how well water bodies support aquatic life. This fact sheet describes current biological conditions of Johnson County streams and characterizes stream biology relative to urban development. Biological conditions were evaluated by collecting macroinvertebrate samples from 15 stream sites in Johnson County, Kansas, in 2003 and 2004 (fig. 1). Data from seven additional sites, collected as part of a separate study with similar objectives in Kansas and Missouri (Wilkison and others, 2005), were evaluated to provide a more comprehensive assessment of watersheds that cross State boundaries. Land-use and water- and streambed-sediment-quality data also were used to evaluate factors that may affect macroinvertebrate communities. Metrics are indices used to measure, or evaluate, macroinvertebrate response to various factors such as human disturbance. Multimetric scores, which integrated 10 different metrics that measure various aspects of macroinvertebrate communities, including organism diversity, composition, tolerance, and feeding characteristics, were used to evaluate and compare biological health of Johnson County streams. This information is useful to city and county officials for defining current biological conditions, evaluating conditions relative to State biological criteria, evaluating effects of urbanization, developing effective water-quality management plans, and documenting changes in biological conditions and water quality.

  16. Estimating Economic Value of Stream Restoration for Urban Watershed Using Choice Experiments

    NASA Astrophysics Data System (ADS)

    Oh, J.; Lee, K. S.; Yoo, J.; Kong, K.; Seoul National University; Chungbuk National University

    2010-12-01

    Since the Yangjaecheon and the Cheonggyecheon project by Seoul city is recognized as starting point of stream restoration project in Korea, many streams having a straight corridor and covered by concrete in an urban watershed have been projected to restore its natural appearance. In some of local autonomous entities the objective of the stream restoration project only deals with improvements in a function of environment which is recreation and amenity for a citizen. Therefore, this study uses the choice experiments based on a citizens preference to estimate economic benefits from stream restoration in an urban watershed. The study area is the downstream section (4.5 km from outlet) of the Mokgamcheon, which had been implementing the restoration project. To apply the choice experiments, 5 attributes are chosen as status-quo of the study area. In an attribute of flood control, Potential Flood Damage (PFD) is estimated. A result of comparison between a maintenance flow and a flow duration curve using PCSWMM model is used to achieve an attribute of water utilization. In an attribute of environment, Assessment of Stream Naturalness considering Physical, Biological, Chemical factors (ASNPBC) is applied to get physical stream appearance, and biological, chemical water quality and Use Index of Stream space for Citizen (UISC) is used to survey how facilities for rest, exercise, amenity and view are distributed in the stream space. The results of an assessment for all attributes are estimated to be the 3rd grade. All the attributes introduced above have 4 level grading systems. The attribute described willingness to pay has 3 levels estimated through a survey from a specialist group. An orthogonal plan is used to avoid collinearity between levels of attributes, and a preliminary survey, which is questioned to students and citizens living in the study area is built to modify survey errors and obtain reasonable results. The population of the main survey is citizens living within 800 m radius of the Mokgamcheon, and the sample size of it is 165 of citizens chosen by simple random samples. Through a main survey, 173 of valid responses were obtained among 223 of all responses. Two of multinomial logit model were constructed to explain preference of respondent, model I: except socio-economic characteristic of respondent, model II: considering socio-economic characteristic of respondent. As a result of model estimation, it was proven that model II is more efficient than model I to explain utility coefficients. If the condition of the Mokgamcheon will be the 1st and the 2nd grade over all attributes, the benefit for citizens living in the study area was estimated to be 12.5 billion won and 9.3 billion won per a year. ASNPBC suggested by this study will be applied to establish a concrete and a feasible objective in the stream restoration, and the economic value of each attributes about stream will be a base datum to apply cost-benefit analysis. The tool of the decision making for a public works can be used to lead citizens to be interested of the project of the stream restoration or the close to nature stream because the choice experiments is based on their preferences.

  17. Anthropogenic influences on hydrology and biota on the Glin?ica stream

    NASA Astrophysics Data System (ADS)

    Koprivek, M.

    2009-04-01

    As the size of the urban population was increasing, stream corridors have become more and more physically changed to ensure flood safety and to increase urban surfaces. For this purpose dams, accumulations, banks and other objects on the stream corridors have been built. Besides, riparian vegetation has been removed; river corridors have been straightened and often made of concrete. In comparison with natural streams, physically changed river corridors have different values of physical, chemical and biotic parameters, which influence self-purification capacity of the streams. We were investigating in which way these parameters were modified due to human influenced changes to river streams on five sampling sites on the Glin?ica stream. For comparison we took another sampling site on its tributary Pranec. First sampling site is located in almost unregulated reach, whereas the other four in regulated reach. Last two sampling sites are located in the reach with concrete channel. Depth of the river, water flow and velocity, composition of organic and inorganic substratum, temperature, dissolved oxygen, conductivity, pH, nitrates and phosphates were studied and also samples of periphyton and macroinvertebrates were taken in all four seasons from spring 2005 till winter 2006. We have found out that downstream water quality decreases with increase of human-caused changes on the stream corridor. Water quality decreases mostly for the insufficiency of shading, which leads to increased water temperature, increased saturation with oxygen and increased pH on sunny summer days. Straightened and concrete river channels cause decreased depth of the river, increased water flow and increased velocity. The main problem for water organisms regarding changing and straightening river channels is that substrate, velocities and depth become homogeneous. This means that there are no different habitats, suitable for different species and that there is no shelter to hide from high velocities, high temperatures and predators. Conditions on the whole corridor are the same and suitable for only few species, so the biodiversity in human-changed river corridors usually declines. All these physical and chemical changes caused by anthropogenic alteration of stream corridors have also different influence on different species of organisms. In ecological part of this study, which was made on Biotechnical Faculty, University of Ljubljana, macroinvertebrates and periphyton in the Glin?ica stream were studied. The investigation shows that influence of anthropogenic alteration is much bigger for macroinvertebrates community as for periphyton community. Changes of macroinvertebrates community were bigger from site to site in comparison with the same site in different seasons. Periphyton community shows different result: changes in community were bigger at the same location in different seasons as from site to site. Biodiversity of macroinvertebrates decreases on the sites with concrete channel, but the biggest value of biodiversity is reached almost by all measurements on physically changed site just before the concrete channel starts. Study of periphyton gives results that are even more surprising: the biggest values of biodiversity of diatoms community at spring and summer measurements were on the sites with the concrete channel. This investigation shows that anthropogenic changes on the stream corridor are not necessary negative for all species living in a stream, but if we want to ensure a good water quality, we have to ensure good living conditions for all the water organisms and the organisms living in surroundings of s stream.

  18. Valuing different human lives.

    PubMed

    Goodwin, Geoffrey P; Landy, Justin F

    2014-04-01

    Do people think of the value of all human lives as equivalent irrespective of age? Affirmations of the equal value of all human lives are culturally prominent, yet much evidence points to the fact that the young are often prioritized over the old in life-and-death decision-making contexts. Studies 1-3 aimed to reconcile this tension by showing that although individuals are seen as more equal with respect to negative rights not to be harmed or killed (though not completely equal), they are seen as less equal with respect to positive rights to be aided or saved. Age exerts a large and systematic impact on decisions about who to save and about whose death is more tragic, suggesting that individuals are seen as possessing differing amounts of contingent value. These initial studies also yielded the novel finding that, although children are prioritized over adults, older children are often prioritized over younger children. Study 4 replicated this finding with a think-aloud methodology; the study showed that the preference for older children appears to be driven by their having had more invested in their lives, their better developed social relations, and their greater understanding of death. Studies 5a-5c demonstrated the independent causal effects of each of these variables on judgments of life's value. Finally, in Studies 6 and 7, mediation methods were used to show that older children's more meaningful social relations primarily explain the greater value of older than of younger children. These findings have implications for bioethics and medical policy. PMID:23647311

  19. Dynamics of living polymers

    NASA Astrophysics Data System (ADS)

    O'Shaughnessy, B.; Vavylonis, D.

    2003-11-01

    We study theoretically the dynamics of living polymers which can add and subtract monomer units at their live chain ends. The classic example is ionic living polymerization. In equilibrium, a delicate balance is maintained in which each initiated chain has a very small negative average growth rate (“velocity”) just sufficient to negate the effect of growth rate fluctuations. This leads to an exponential molecular weight distribution (MWD) with mean bar{N}. After a small perturbation of relative amplitude ɛ, e.g. a small temperature jump, this balance is destroyed: the velocity acquires a boost greatly exceeding its tiny equilibrium value. For ɛ > ɛ_c≈ 1/bar{N}^{1/2} the response has 3 stages: (1) Coherent chain growth or shrinkage, leaving a highly non-linear hole or peak in the MWD at small chain lengths. During this episode, lasting time tau_fastsimbar{N}, the MWD's first moment and monomer concentration m relax very close to equilibrium. (2) Hole-filling (or peak decay) after tau_fillsim ɛ^2 bar{N}^2. The absence or surfeit of small chains is erased. (3) Global MWD shape relaxation after tau_slowsim bar{N}^2. By this time second and higher MWD moments have relaxed. During episodes (2) and (3) the fast variables (bar{N},m) are enslaved to the slowly varying number of free initiators (chains of zero length). Thus fast variables are quasi-statically fine-tuned to equilibrium. The outstanding feature of these dynamics is their ultrasensitivity: despite the perturbation's linearity, the response is non-linear until the late episode (3). For very small perturbations, ɛ < ɛ_c, response remains non-linear but with a less dramatic peak or hole during episode (1). Our predictions are in agreement with viscosity measurements on the most widely studied system, α-methylstyrene.

  20. Living with a Single Parent

    MedlinePLUS

    ... Body Works Main Page Living With a Single Parent KidsHealth > Kids > Feelings > My Home & Family > Living With ... parents can be a great idea, too. Single Parents and Work Single parents are often working parents ...

  1. Web Audio/Video Streaming Tool

    NASA Technical Reports Server (NTRS)

    Guruvadoo, Eranna K.

    2003-01-01

    In order to promote NASA-wide educational outreach program to educate and inform the public of space exploration, NASA, at Kennedy Space Center, is seeking efficient ways to add more contents to the web by streaming audio/video files. This project proposes a high level overview of a framework for the creation, management, and scheduling of audio/video assets over the web. To support short-term goals, the prototype of a web-based tool is designed and demonstrated to automate the process of streaming audio/video files. The tool provides web-enabled users interfaces to manage video assets, create publishable schedules of video assets for streaming, and schedule the streaming events. These operations are performed on user-defined and system-derived metadata of audio/video assets stored in a relational database while the assets reside on separate repository. The prototype tool is designed using ColdFusion 5.0.

  2. Reactive solute transport in acidic streams

    USGS Publications Warehouse

    Broshears, R.E.

    1996-01-01

    Spatial and temporal profiles of Ph and concentrations of toxic metals in streams affected by acid mine drainage are the result of the interplay of physical and biogeochemical processes. This paper describes a reactive solute transport model that provides a physically and thermodynamically quantitative interpretation of these profiles. The model combines a transport module that includes advection-dispersion and transient storage with a geochemical speciation module based on MINTEQA2. Input to the model includes stream hydrologic properties derived from tracer-dilution experiments, headwater and lateral inflow concentrations analyzed in field samples, and a thermodynamic database. Simulations reproduced the general features of steady-state patterns of observed pH and concentrations of aluminum and sulfate in St. Kevin Gulch, an acid mine drainage stream near Leadville, Colorado. These patterns were altered temporarily by injection of sodium carbonate into the stream. A transient simulation reproduced the observed effects of the base injection.

  3. Flood-frequency characteristics of Wisconsin streams

    USGS Publications Warehouse

    Walker, John F.; Krug, William R.

    2003-01-01

    Flood-frequency characteristics for 312 gaged sites on Wisconsin streams are presented for recurrence intervals of 2 to 100 years using flood-peak data collected through water year 2000. Equations of the relations between flood-frequency and drainage-basin characteristics were developed by multiple-regression analyses. Flood-frequency characteristics for ungaged sites on unregulated, rural streams can be estimated by use of these equations. The state was divided into five areas with similar physiographic characteristics. The most significant basin characteristics are drainage area, main-channel slope, soil permeability, storage, rainfall intensity, and forest cover. The standard error of prediction for the equation for the 100-year flood discharge ranges from 22 to 44 percent in the state. A graphical method for estimating flood-frequency characteristics of regulated streams was developed from the relation of discharge and drainage area. Graphs for the major regulated streams are presented.

  4. Dissolved oxygen in streams and reservoirs

    SciTech Connect

    Kim, B.R.; Ruane, R.J.

    1980-06-01

    Stream standards, monitoring, surface runoff, water quality, runoff models, river models, reservoir models, planning models, nitrification, effects of photosynthesis on dissolved oxygen and oxygen transfer are mentioned in this review. (DAD)

  5. A Bridge over Troubled Waters: Project STREAM.

    ERIC Educational Resources Information Center

    Britton, Michele; Knutson, Zandra

    1979-01-01

    Project STREAM (Special Training in Remedial Education Activities for Mainstreaming), a program providing regular elementary teachers with skills to individualize programs for handicapped children in their regular classrooms, is described. (PHR)

  6. Stream ecology in an Alaskan tundra watershed

    SciTech Connect

    Oswood, M.W.

    1991-03-01

    This study was part of the R4D Project'', a large, multi- investigator study of an arctic watershed on the Alaskan North Slope. The ultimate goal of this program was to examine the response, resistance, and resilience to, and recovery from disturbances in arctic tundra ecosystems (hence, R4D). This report concerns the Steam Ecology portion of the R4D, project under the direction of Dr. Mark Oswood. Consideration of arctic streams is critical to rational management of the arctic landscape. Since streams drain upslope areas, disturbances visited upon valley slopes often have unwelcome consequences to the stream at the bottom of the valley. Degradation of water quality is generally not limited to a localized stretch of stream but transported some distance downstream and may involve changes in water quality or fish and wildlife populations in downstream rivers lakes, or estuaries. 14 refs.

  7. Water Stream "Loop-the-Loop"

    ERIC Educational Resources Information Center

    Jefimenko, Oleg

    1974-01-01

    Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)

  8. Noise Prediction Module for Offset Stream Nozzles

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda S.

    2011-01-01

    A Modern Design of Experiments (MDOE) analysis of data acquired for an offset stream technology was presented. The data acquisition and concept development were funded under a Supersonics NRA NNX07AC62A awarded to Dimitri Papamoschou at University of California, Irvine. The technology involved the introduction of airfoils in the fan stream of a bypass ratio (BPR) two nozzle system operated at transonic exhaust speeds. The vanes deflected the fan stream relative to the core stream and resulted in reduced sideline noise for polar angles in the peak jet noise direction. Noise prediction models were developed for a range of vane configurations. The models interface with an existing ANOPP module and can be used or future system level studies.

  9. Salt vulnerability assessment methodology for urban streams

    NASA Astrophysics Data System (ADS)

    Betts, A. R.; Gharabaghi, B.; McBean, E. A.

    2014-09-01

    De-icing agents such as road salts while used for winter road maintenance can cause negative effects on urban stream water quality and drinking water supplies. A new methodology using readily available spatial data to identify Salt Vulnerable Areas (SVAs) for urban streams is used to prioritize implementation of best management practices. The methodology calculates the probable chloride concentration statistics at specified points in the urban stream network and compares the results with known aquatic species exposure tolerance limits to characterize the vulnerability scores. The approach prioritizes implementation of best management practices to areas identified as vulnerable to road salt. The vulnerability assessment is performed on seven sites in four watersheds in the Greater Toronto Area and validated using the Hanlon Creek watershed in Guelph. The mean annual in-stream chloride concentration equation uses readily available spatial data - with province-wide coverage - that can be easily used in any urban watershed.

  10. A dynamically reconfigurable data stream processing system

    SciTech Connect

    Nogiec, J.M.; Trombly-Freytag, K.; /Fermilab

    2004-11-01

    This paper describes a component-based framework for data stream processing that allows for configuration, tailoring, and runtime system reconfiguration. The system's architecture is based on a pipes and filters pattern, where data is passed through routes between components. A network of pipes and filters can be dynamically reconfigured in response to a preplanned sequence of processing steps, operator intervention, or a change in one or more data streams. This framework provides several mechanisms supporting dynamic reconfiguration and can be used to build static data stream processing applications such as monitoring or data acquisition systems, as well as self-adjusting systems that can adapt their processing algorithm, presentation layer, or data persistency layer in response to changes in input data streams.

  11. Economic recovery of nutrients from waste streams

    SciTech Connect

    Nuzum, J.M.; Pepperman, R.E.

    1995-12-31

    This paper describes an economical means to recover nutrients from organic waste streams and, as an alternative to disposal, formulate them into high integrity granules for agriculture and specialty fertilizer products. Generators of waste streams such as manures, litters and sludges are becoming both financially and physically burdened with accessing adequate land for waste application. With mandated farm nutrient management planning, low cost land application of organic wastes is increasingly controlled. Many states limit waste application rates by nitrogen or phosphorous loadings tied to the needs of the subsequent crop and further reduce application rates by taking into account the nutrients from other materials, including crop residue, commercial fertilizers and current or previous applications of other waste streams. Although most of the waste streams are dilute, low density, amorphous and generally unusable in their raw forms, technology exists to upgrade them into high value products.

  12. A kinetic cross-field streaming instability

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Winske, D.; Papadopoulos, K.; Zhou, Y. M.; Tsai, S. T.; Guo, S. C.

    1983-01-01

    In a high-beta plasma the so-called modified-two-stream instability, which results from strongly magnetized electrons drifting relative to unmagnetized ions across a homogeneous magnetic field, is misnamed because the mode is highly kinetic, particularly when the relative streaming velocity exceeds the Alfven speed of the plasma. This kinetic cross-field streaming instability is investigated in detail, examining the effect of the electromagnetic terms and the stability boundaries in both low- and high-beta plasmas. An approximate dispersion relation showing the relation of this mode to the whistler is derived and solutions of it are compared with those obtained from the exact dispersion relation. The kinetic mode, unlike the usual modified-two-stream instability, is not stabilized by electromagnetic effects when the relative electron-ion drift speed exceeds the Alfven speed.

  13. WHITE DWARFS IN LOCAL STAR STREAMS

    SciTech Connect

    Fuchs, Burkhard; Dettbarn, Christian

    2011-01-15

    We have studied the fine structure of the phase space distribution of white dwarfs in the solar neighborhood. White dwarfs have kinematics that are typical for the stellar population of the old thin disk of the Milky Way. Using a projection of the space velocities of stars onto vertical angular momentum components and eccentricities of the stellar orbits we demonstrate that stellar streams can be identified in the phase space distribution of the white dwarfs. These correspond to the well-known Sirius, Pleiades, and Hercules star streams. Membership of white dwarfs, which represent the oldest population in the Galaxy, in these streams lends support to the interpretation that the streams owe their existence to dynamical resonance effects of the stars with Galactic spiral arms or the Galactic bar, because these indiscriminately affect all stellar populations.

  14. Living in Space

    NASA Technical Reports Server (NTRS)

    Brown, Ray (editor)

    1993-01-01

    In this educational video from the 'Liftoff to Learning' series, astronauts from the STS-56 Mission (Ken Cockrell, Mike Foale, Ellen Ochoa, Steve Oswald, and Ken Cameron) explain and show through demonstrations how microgravity affects the way astronauts live onboard the Space Shuttle, and how these same daily habits or processes differ on Earth. A tour of the Space Shuttle is given, including the sleeping compartments, the kitchen area, the storage compartments, and the Waste Collection System (or WCS, as they call it). Daily habits (brushing teeth, shampooing hair and bathing, eating,...) are explained and actively illustrated, along with reasons of how these applications differ from their employment on Earth.

  15. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Bauman, Robert

    2006-11-14

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  16. Microencapsulation Of Living Cells

    NASA Technical Reports Server (NTRS)

    Chang, Manchium; Kendall, James M.; Wang, Taylor G.

    1989-01-01

    In experimental technique, living cells and other biological materials encapsulated within submillimeter-diameter liquid-filled spheres. Sphere material biocompatible, tough, and compliant. Semipermeable, permitting relatively small molecules to move into and out of sphere core but preventing passage of large molecules. New technique promises to make such spherical capsules at high rates and in uniform, controllable sizes. Capsules injected into patient through ordinary hypodermic needle. Promising application for technique in treatment of diabetes. Also used to encapsulate pituitary cells and thyroid hormone adrenocortical cells for treatment of other hormonal disorders, to encapsulate other secreting cells for transplantation, and to package variety of pharmaceutical products and agricultural chemicals for controlled release.

  17. "Living versus Dead":

    PubMed Central

    Chakrabarti, Pratik

    2010-01-01

    Summary The Semple antirabies vaccine was developed by David Semple in India in 1911. Semple introduced a peculiarly British approach within the Pasteurian tradition by using carbolized dead virus. This article studies this unique phase of vaccine research between 1910 and 1935 to show that in the debates and laboratory experiments around the potency and safety of vaccines, categories like "living" and "dead" were often used as ideological and moral denominations. These abstract and ideological debates were crucial in defining the final configuration of the Semple vaccine, the most popular antirabies vaccine used globally, and also in shaping international vaccination policies. PMID:21037397

  18. Communication in Assisted Living*

    PubMed Central

    Williams, Kristine N.; Warren, Carol A.B.

    2009-01-01

    This study of communication in an Assisted Living Facility (ALF) focuses on staff’s interpretive frameworks and situational tactics for managing elderly residents. It is based on interviews with staff and residents in an ALF together with ethnographic fieldwork. As in other quasi-total institutions, staff members engage in control as well as care, monitoring residents for compliance with rules and directives. Residents, aware of the threat of being moved to a nursing home, also monitor their own behavior and cognition in comparison to other residents. Other communication issues include the infantilization of the elderly by staff, and the race, class, and ethnic prejudices of residents. PMID:20107612

  19. Living olefin polymerization processes

    DOEpatents

    Schrock, R.R.; Baumann, R.

    1999-03-30

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  20. Microholography of Living Organisms

    NASA Astrophysics Data System (ADS)

    Solem, Johndale C.; Baldwin, George C.

    1982-10-01

    By using intense pulsed coherent x-ray sources that are currently under development, it will be possible to obtain magnified three-dimensional images of elementary biological structures in the living state at precisely defined instants. For optimum contrast, sensitivity, and resolution, the hologram should be made with x-rays tuned to a resonance of nitrogen near 0.3 nanometer. Resolution will then be limited mainly by the hydrodynamic expansion that occurs while the necessary number of photons is being registered. Problems of technique are also briefly discussed.

  1. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Baumann, Robert

    2003-08-26

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  2. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R. (Winchester, MA); Baumann, Robert (Cambridge, MA)

    1999-01-01

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  3. Data Streams: An Overview and Scientific Applications

    NASA Astrophysics Data System (ADS)

    Aggarwal, Charu C.

    In recent years, advances in hardware technology have facilitated the ability to collect data continuously. Simple transactions of everyday life such as using a credit card, a phone, or browsing the web lead to automated data storage. Similarly, advances in information technology have lead to large flows of data across IP networks. In many cases, these large volumes of data can be mined for interesting and relevant information in a wide variety of applications. When the volume of the underlying data is very large, it leads to a number of computational and mining challenges: With increasing volume of the data, it is no longer possible to process the data efficiently by using multiple passes. Rather, one can process a data item at most once. This leads to constraints on the implementation of the underlying algorithms. Therefore, stream mining algorithms typically need to be designed so that the algorithms work with one pass of the data. In most cases, there is an inherent temporal component to the stream mining process. This is because the data may evolve over time. This behavior of data streams is referred to as temporal locality. Therefore, a straightforward adaptation of one-pass mining algorithms may not be an effective solution to the task. Stream mining algorithms need to be carefully designed with a clear focus on the evolution of the underlying data. Another important characteristic of data streams is that they are often mined in a distributed fashion. Furthermore, the individual processors may have limited processing and memory. Examples of such cases include sensor networks, in which it may be desirable to perform in-network processing of data stream with limited processing and memory [1, 2]. This chapter will provide an overview of the key challenges in stream mining algorithms which arise from the unique setup in which these problems are encountered. This chapter is organized as follows. In the next section, we will discuss the generic challenges that stream mining poses to a variety of data management and data mining problems. The next section also deals with several issues which arise in the context of data stream management. In Sect. 3, we discuss several mining algorithms on the data stream model. Section 4 discusses various scientific applications of data streams. Section 5 discusses the research directions and conclusions.

  4. Polymictic pool behavior in Sierra Nevada Streams

    NASA Astrophysics Data System (ADS)

    Lucas, R. G.; Conklin, M. H.; Tyler, S. W.; Suarez, F. I.; Moran, J. E.; Esser, B. K.

    2010-12-01

    Pools in streams and meadows in the mid to high Sierra Nevada (1800-2300 m) in low flow scenarios were observed to exhibit polymictic behavior during summer months. Although daily thermal stratification has been observed in pools of various sizes and in multiple locations, the degree and timing of stratification is highly variable and not well understood. Previous studies have shown that thermally stratified stream pools can provide cold water refugia for thermally sensitive species, specifically salmonid fish. Diel temperature patterns demonstrating daily thermal stratification and nightly mixing of small (1-4 m diameter and 1-2 m deep) pools in the Long Meadow complex (Sequoia National Park, CA) were observed during the deployment of a distributed temperature sensor (DTS) in 2008. Similar behavior was also noted in stream pools along Chilnualna Creek, a tributary of the South Fork of the Merced River, Yosemite National Park, CA. To further investigate this polymictic behavior, we developed a two-dimensional model of water temperature and flow using Fluent, a computational fluid dynamics solver. The model successfully simulated thermal patterns similar to those observed and indicated that groundwater inflow has a significant influence on pool stratification, consistent with observed low temperatures and raised Radon-222 activity in highly localized areas in the pool bottoms. Similar polymictic behavior was observed in larger (4-10 m diameter and 1.5-2 m deep) stream pools on Chilnualna Creek in the late summer under baseflow conditions. The significant factors that determine stratification or mixing conditions are stream flow velocity, groundwater influence, and density variations due to radiative heating. We use the Richardson number, which was originally developed for assessing thermal stratification in lakes and reservoirs, to develop a one-dimensional tool for prediction of stream pool stratification at multiple scales. This application allows us to assess the stream velocity versus the density discrepancy dictated by the thermal gradient of a given stream pool. Using approximations of stream velocity, stream and groundwater temperatures, we can predict the potential for a stream pool to provide a refuge of cold water.

  5. Variations in Heavy Metals Across Urban Streams

    NASA Astrophysics Data System (ADS)

    Kaushal, S. S.; Belt, K. T.; Stack, W. P.; Pouyat, R. V.; Groffman, P. M.; F, S. E.

    2006-05-01

    Urbanization has led to increased concentrations of metals such as lead (Pb), zinc (Zn), and copper (Cu) in streams due to industrial sources, domestic activities, vehicle use, and runoff from roadways. These metals can be dangerous to aquatic organisms and humans at high concentrations. We investigated variations in concentrations of heavy metals in streams across Baltimore, Maryland and within the context of convergent increases in salinity and organic carbon (two important variables that are known to affect metal transport in surface waters) due to urbanization. Despite past reductions of lead in gasoline and paints, mean concentrations of lead in some Baltimore streams were still approximately 75 micrograms/L and exceeded the U.S. EPA recommended criteria by 50 times. Mean concentrations of zinc and copper across Baltimore streams were also elevated and ranged between 15 to 140 micrograms/L and 2 to 40 micrograms/L, and mean concentrations of these metals were considerably higher than national means reported by the National Storm Water Quality database (NSWQ), which spans 3,770 storm events across the U.S. There were substantial increases in concentrations of heavy metals in streams during storms with greater than 80 percent, 70 percent, and 20 percent of storm samples exceeding recommended U.S. EPA metals criteria for Cu, Pb, and Zn respectively. Relationships between metal concentrations and stream discharge followed different patterns than nitrate and total phosphorus, other regulated pollutants in the Chesapeake Bay watershed, suggesting differences in sources and transport mechanisms within watersheds. Environmental factors such as increasing salinity from deicer use (with chloride concentrations in streams now ranging up to 5 g/L) may contribute to elevated transport of metals through ion exchange and mobilization of metals in soils and sediments. Environmental factors such as increasing organic carbon in urban streams, with ranges of 2 - 16 times greater in suburban and urban streams than forest watersheds, may also act as a vector for transporting metals due to binding capacity. Results show that metals appear to be present in harmful concentrations in many streams in Baltimore, Maryland, but further work is needed to elucidate shifts in the origin of metal pollution (storage in soils and sediments vs. roadway surfaces), and the effects of widespread changes in environmental factors that can potentially enhance their mobilization to streams.

  6. Stream-network navigation in the U.S. Geological Survey StreamStats Web Application

    USGS Publications Warehouse

    Ries, Kernell G., III; Steeves, Peter A.; Guthrie, John D.; Rea, Alan H.; Stewart, David W.

    2009-01-01

    StreamStats is a U.S. Geological Survey Webbased geographic information systems application developed as a tool for water-resources planning and management, engineering design, and other applications. The primary functionality of StreamStats allows users to obtain drainage-basin boundaries, basin characteristics, and streamflow statistics for gaged and ungaged sites. Recently, tools that allow stream-network navigation were added to StreamStats. These tools allow users to select any point along a stream and locate activities upstream and downstream from the selected point, such as streamgaging stations, dams, and point-source discharges, and obtain information about such activities. Users also can obtain stream-reach addresses and estimates of streamflow statistics for the selected points.

  7. Stream-Network navigation in the U.S. geological survey streamStats web application

    USGS Publications Warehouse

    Ries, K.G.; Steeves, P.A.; Guthrie, J.D.; Rea, A.H.; Stewart, D.W.

    2009-01-01

    StreamStats is a U.S. Geological Survey Webbased geographic information systems application developed as a tool for water-resources planning and management, engineering design, and other applications. The primary functionality of StreamStats allows users to obtain drainage-basin boundaries, basin characteristics, and streamflow statistics for gaged and ungaged sites. Recently, tools that allow stream-network navigation were added to StreamStats. These tools allow users to select any point along a stream and locate activities upstream and downstream from the selected point, such as streamgaging stations, dams, and point-source discharges, and obtain information about such activities. Users also can obtain stream-reach addresses and estimates of streamflow statistics for the selected points.

  8. Wireless image streaming in mobile ultrasound.

    PubMed

    Dickson, Brett W; Pedersen, Peder C

    2010-03-01

    This work evaluates the feasibility of using 802.11 g ad hoc and 3G cellular broadband networks to wirelessly stream ultrasound video in real-time. Telemedicine ultrasound applications in events such as disaster relief and first-response triage can incorporate these technologies, enabling onsite medical personnel to receive assistance with diagnostic decisions by remote medical experts. The H.264 scalable video codec was used to encode echocardiographic video streams at various image resolutions (video graphics array [VGA] and quarter video graphics array [QVGA]) and frame rates (10, 15, 20, and 30 frames/s). The video stream was transmitted using 802.11 g and 3G cellular technologies, and pertinent transmission parameters such as data rate, packet loss, delay jitter, and latency were measured. 802.11 g permits high frame rate and VGA resolution and has low latency and jitter, but it is suitable only for short communication ranges, whereas the 3G cellular network allows medium to low frame rate streaming at QVGA image resolution with medium latency. However, video streaming can take place from any location with 3G service to any other site with Internet connectivity. The transmitted ultrasound video streams were subsequently recorded and evaluated by physicians with expertise in medical ultrasonography who evaluated the diagnostic value of the received video streams relative to the original videos. They expressed the opinion that image quality in the case of both 802.11 g and 3G was fully to adequately preserved, but missed frames could momentarily decrease the diagnostic value. This research demonstrates that 3G and 802.11 g wireless networks combined with efficient video compression make diagnostically valuable wireless streaming of ultrasound video feasible. PMID:20136557

  9. Rotenone persistence model for montane streams

    USGS Publications Warehouse

    Brown, Peter J.; Zale, Alexander V.

    2012-01-01

    The efficient and effective use of rotenone is hindered by its unknown persistence in streams. Environmental conditions degrade rotenone, but current label instructions suggest fortifying the chemical along a stream based on linear distance or travel time rather than environmental conditions. Our objective was to develop models that use measurements of environmental conditions to predict rotenone persistence in streams. Detailed measurements of ultraviolet radiation, water temperature, dissolved oxygen, total dissolved solids (TDS), conductivity, pH, oxidationreduction potential (ORP), substrate composition, amount of organic matter, channel slope, and travel time were made along stream segments located between rotenone treatment stations and cages containing bioassay fish in six streams. The amount of fine organic matter, biofilm, sand, gravel, cobble, rubble, small boulders, slope, pH, TDS, ORP, light reaching the stream, energy dissipated, discharge, and cumulative travel time were each significantly correlated with fish death. By using logistic regression, measurements of environmental conditions were paired with the responses of bioassay fish to develop a model that predicted the persistence of rotenone toxicity in streams. This model was validated with data from two additional stream treatment reaches. Rotenone persistence was predicted by a model that used travel time, rubble, and ORP. When this model predicts a probability of less than 0.95, those who apply rotenone can expect incomplete eradication and should plan on fortifying rotenone concentrations. The significance of travel time has been previously identified and is currently used to predict rotenone persistence. However, rubble substrate, which may be associated with the degradation of rotenone by adsorption and volatilization in turbulent environments, was not previously considered.

  10. Updates to the MSFC Meteoroid Stream Model

    NASA Technical Reports Server (NTRS)

    Moser, D. E.; Cooke, W. J.

    2007-01-01

    The Marshall Space Flight Center (MSFC) Meteoroid Stream Model simulates particle ejection and subsequent evolution from comets in order to provide meteor shower forecasts to spacecraft operators for hazard mitigation and planning purposes. The model, previously detailed, has recently been updated; the changes include the implementation of the RADAU integrator, an improved planetary treatment, and the inclusion of general relativistic effects in the force function. The results of these updates are investigated with respect to various meteoroid streams and the outcome presented.

  11. Mining for Surprise Events within Text Streams

    SciTech Connect

    Whitney, Paul D.; Engel, David W.; Cramer, Nicholas O.

    2009-04-30

    This paper summarizes algorithms and analysis methodology for mining the evolving content in text streams. Text streams include news, press releases from organizations, speeches, Internet blogs, etc. These data are a fundamental source for detecting and characterizing strategic intent of individuals and organizations as well as for detecting abrupt or surprising events within communities. Specifically, an analyst may need to know if and when the topic within a text stream changes. Much of the current text feature methodology is focused on understanding and analyzing a single static collection of text documents. Corresponding analytic activities include summarizing the contents of the collection, grouping the documents based on similarity of content, and calculating concise summaries of the resulting groups. The approach reported here focuses on taking advantage of the temporal characteristics in a text stream to identify relevant features (such as change in content), and also on the analysis and algorithmic methodology to communicate these characteristics to a user. We present a variety of algorithms for detecting essential features within a text stream. A critical finding is that the characteristics used to identify features in a text stream are uncorrelated with the characteristics used to identify features in a static document collection. Our approach for communicating the information back to the user is to identify feature (word/phrase) groups. These resulting algorithms form the basis of developing software tools for a user to analyze and understand the content of text streams. We present analysis using both news information and abstracts from technical articles, and show how these algorithms provide understanding of the contents of these text streams.

  12. Side Stream Filtration for Cooling Towers

    SciTech Connect

    2012-10-20

    This technology evaluation assesses side stream filtration options for cooling towers, with an objective to assess key attributes that optimize energy and water savings along with providing information on specific technology and implementation options. This information can be used to assist Federal sites to determine which options may be most appropriate for their applications. This evaluation provides an overview of the characterization of side stream filtration technology, describes typical applications, and details specific types of filtration technology.

  13. In-Stream Metabolism Differences Between Glacial and Non-Glacial Streams in Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Nassry, M. Q.; Scott, D.; Vermilyea, A.; Hood, E. W.

    2011-12-01

    As glacier ice gives way to successional vegetation, streams located in glacier-containing watersheds receive decreased contributions from glacial meltwater and increased contributions from terrestrial landscapes. These changes result in increased water temperature, increased shading from vegetation, and changes in the composition and concentration of organic matter delivered to the stream from the landscape. Organic matter and source water contributions from the surrounding landscape can influence in-stream metabolism through both biotic and abiotic factors. The impact of these landscape controls on the in-stream cycling of carbon and nutrients is not well understood in glacial systems. Here, we are focusing on understanding the differences in processing of organic carbon by heterotrophic microbial communities between glacial and non-glacial streams. In this study, the metabolism in streams receiving glacial meltwater was compared to the metabolism of streams located in nearby non-glaciated watersheds to determine the effect of changing inputs of glacial meltwater on stream metabolism. In particular, we tested the hypothesis that decreased inputs of glacier meltwater will result in increased net ecosystem metabolism (NEM) in coastal streams in southeast Alaska. Dissolved oxygen and carbon dioxide measurements as well as temperature and PAR values were collected at 10-minute increments at each study site for 4 days. This data was used to generate diel curves to establish community respiration (CR24) and gross primary production (GPP) estimates. Lab-scale mesocosms containing sediment and stream water from each end-member stream were used to quantify the relative importance of glacial contributions to respiration rates in the surface sediments. Ultimately, this will provide a better understanding of the changing in-stream processing capabilities in watersheds affected by land cover changes resulting from glacial recession.

  14. Effects of unsteady free stream velocity and free stream turbulence on stagnation point heat transfer

    NASA Technical Reports Server (NTRS)

    Gorla, R. S. R.

    1984-01-01

    The combined effects of transient free stream velocity and free stream turbulence on heat transfer at a stagnation point over a cylinder situated in a crossflow are studied. An eddy diffusivity model was formulated and the governing momentum and energy equations are integrated by means of the steepest descent method. The numerical results for the wall shear stress and heat transfer rate are correlated by a turbulence parameter. The wall friction and heat transfer rate increase with increasing free stream turbulence intensity.

  15. Carbon and nitrogen transfer from a desert stream to riparian predators.

    PubMed

    Sanzone, D M; Meyer, J L; Marti, E; Gardiner, E P; Tank, J L; Grimm, N B

    2003-01-01

    Adult aquatic insects emerging from streams may be a significant source of energy for terrestrial predators inhabiting riparian zones. In this study, we use natural abundance delta(13)C and delta(15)N values and an isotopic (15)N tracer addition to quantify the flow of carbon and nitrogen from aquatic to terrestrial food webs via emerging aquatic insects. We continuously dripped labeled (15)N-NH(4) for 6 weeks into Sycamore Creek, a Sonoran desert stream in the Tonto National Forest (central Arizona) and traced the flow of tracer (15)N from the stream into spiders living in the riparian zone. After correcting for natural abundance delta(15)N, we used isotopic mixing models to calculate the proportion of (15)N from emerging aquatic insects incorporated into spider biomass. Natural abundance delta(13)C values indicate that orb-web weaving spiders inhabiting riparian vegetation along the stream channel obtain almost 100% of their carbon from instream sources, whereas ground-dwelling hunting spiders obtain on average 68% of their carbon from instream sources. During the 6-week period of the (15)N tracer addition, orb-web weaving spiders obtained on average 39% of their nitrogen from emerging aquatic insects, whereas spider species hunting on the ground obtained on average 25% of their nitrogen from emerging aquatic insects. To determine if stream subsidies might be influencing the spatial distribution of terrestrial predators, we measured the biomass, abundance and diversity of spiders along a gradient from the active stream channel to a distance of 50 m into the upland using pitfall traps and timed sweep net samples. Spider abundance, biomass and richness were highest within the active stream channel but decreased more than three-fold 25 m from the wetted stream margin. Changes in structural complexity of vegetation, ground cover or terrestrial prey abundance could not account for patterns in spider distributions, however nutrient and energy subsidies from the stream could explain elevated spider numbers and richness within the active stream channel and riparian zone of Sycamore Creek. PMID:12647165

  16. STREAMS - Supporting Underrepresented Groups in Earth Sciences

    NASA Astrophysics Data System (ADS)

    Carvalho-Knighton, K.; Johnson, A.

    2009-12-01

    In Fall 2008, STREAMS (Supporting Talented and Remarkable Environmental And Marine Science students) Scholarship initiative began at the University of South Florida St. Petersburg, the only public university in Pinellas County. STREAMS is a partnership between the University of South Florida St. Petersburg’s (USFSP) Environmental Science and Policy Program and University of South Florida’s (USF) College of Marine Science. The STREAMS Student Scholarship Program has facilitated increased recruitment, retention, and graduation of USFSP environmental science and USF marine science majors. The STREAMS program has increased opportunities for minorities and women to obtain undergraduate and graduate degrees, gain valuable research experience and engage in professional development activities. STREAMS scholars have benefited from being mentored by USFSP and USF faculty and as well as MSPhDs students and NSF Florida-Georgia LSAMP Bridge to Doctorate graduate fellows. In addition, STREAMS has facilitated activities designed to prepare student participants for successful Earth system science-related careers. We will elucidate the need for this initiative and vision for the collaboration.

  17. Effective discharge in Rocky Mountain headwater streams

    NASA Astrophysics Data System (ADS)

    Bunte, Kristin; Abt, Steven R.; Swingle, Kurt W.; Cenderelli, Dan A.

    2014-11-01

    Whereas effective discharge (Qeff) in mountain streams is commonly associated with a moderate flow such as bankfull discharge (Qbf), this study found that the maximum discharge (Qmax), and not bankfull discharge, is the channel forming or effective flow for gravel transport in plane-bed streams where partial bed mobility causes steep gravel transport rating curves. Qeff may approach bankfull flow in some step-pool channels where gravel moves over a static cobble/boulder bed. Our conclusions are based on magnitude-frequency analyses conducted at 41 gauged Rocky Mountain headwater streams. Because these gauged streams lacked gravel transport data, as is typical, comparable streams with measured transport rates were used to develop scaling relations for rating curve exponents with stream and watershed characteristics. Those scaling relations were then used to estimate the steepness of gravel rating curves at the 41 gauged but unsampled sites. The measured flow frequency distributions were characterized by two fitted power functions. The steepness of the flow frequency distributions and the estimated steepness of gravel transport relations were combined in magnitude-frequency analyses to compute Qeff.

  18. REVISED STREAM CODE AND WASP5 BENCHMARK

    SciTech Connect

    Chen, K

    2005-05-01

    STREAM is an emergency response code that predicts downstream pollutant concentrations for releases from the SRS area to the Savannah River. The STREAM code uses an algebraic equation to approximate the solution of the one dimensional advective transport differential equation. This approach generates spurious oscillations in the concentration profile when modeling long duration releases. To improve the capability of the STREAM code to model long-term releases, its calculation module was replaced by the WASP5 code. WASP5 is a US EPA water quality analysis program that simulates one-dimensional pollutant transport through surface water. Test cases were performed to compare the revised version of STREAM with the existing version. For continuous releases, results predicted by the revised STREAM code agree with physical expectations. The WASP5 code was benchmarked with the US EPA 1990 and 1991 dye tracer studies, in which the transport of the dye was measured from its release at the New Savannah Bluff Lock and Dam downstream to Savannah. The peak concentrations predicted by the WASP5 agreed with the measurements within {+-}20.0%. The transport times of the dye concentration peak predicted by the WASP5 agreed with the measurements within {+-}3.6%. These benchmarking results demonstrate that STREAM should be capable of accurately modeling releases from SRS outfalls.

  19. Living liquid crystals

    PubMed Central

    Zhou, Shuang; Sokolov, Andrey; Lavrentovich, Oleg D.; Aranson, Igor S.

    2014-01-01

    Collective motion of self-propelled organisms or synthetic particles, often termed “active fluid,” has attracted enormous attention in the broad scientific community because of its fundamentally nonequilibrium nature. Energy input and interactions among the moving units and the medium lead to complex dynamics. Here, we introduce a class of active matter––living liquid crystals (LLCs)––that combines living swimming bacteria with a lyotropic liquid crystal. The physical properties of LLCs can be controlled by the amount of oxygen available to bacteria, by concentration of ingredients, or by temperature. Our studies reveal a wealth of intriguing dynamic phenomena, caused by the coupling between the activity-triggered flow and long-range orientational order of the medium. Among these are (i) nonlinear trajectories of bacterial motion guided by nonuniform director, (ii) local melting of the liquid crystal caused by the bacteria-produced shear flows, (iii) activity-triggered transition from a nonflowing uniform state into a flowing one-dimensional periodic pattern and its evolution into a turbulent array of topological defects, and (iv) birefringence-enabled visualization of microflow generated by the nanometers-thick bacterial flagella. Unlike their isotropic counterpart, the LLCs show collective dynamic effects at very low volume fraction of bacteria, on the order of 0.2%. Our work suggests an unorthodox design concept to control and manipulate the dynamic behavior of soft active matter and opens the door for potential biosensing and biomedical applications. PMID:24474746

  20. RACE AS LIVED EXPERIENCE

    PubMed Central

    Garcia, John A.; Sanchez, Gabriel R.; Sanchez-Youngman, Shannon; Vargas, Edward D.; Ybarra, Vickie D.

    2015-01-01

    A growing body of social science research has sought to conceptualize race as a multidimensional concept in which context, societal relations, and institutional dynamics are key components. Utilizing a specially designed survey, we develop and use multiple measures of race (skin color, ascribed race, and discrimination experiences) to capture race as “lived experience” and assess their impact on Latinos’ self-rated health status. We model these measures of race as a lived experience to test the explanatory power of race, both independently and as an integrated scale with categorical regression, scaling, and dimensional analyses. Our analyses show that our multiple measures of race have significant and negative effects on Latinos’ self-reported health. Skin color is a dominant factor that impacts self-reported health both directly and indirectly. We then advocate for the utilization of multiple measures of race, adding to those used in our analysis, and their application to other health and social outcomes. Our analysis provides important contributions across a wide range of health, illness, social, and political outcomes for communities of color. PMID:26681972

  1. MICROTURBULENCE IN GRAVEL BED STREAMS

    NASA Astrophysics Data System (ADS)

    Papanicolaou, T.; Tsakiris, A. G.; Kramer, C. M.

    2009-12-01

    The overarching objective of this investigation was to evaluate the role of relative submergence on the formation and evolution of cluster microforms in gravel bed streams and its implications to bedload transport. Secondary objectives of this research included (1) a detailed analysis of mean flow measurements around a clast; and (2) a selected number of experimental runs where the mean flow characteristics are linked together with the bed micro-topography observations around a clast. It is hypothesized that the relative submergence is an important parameter in defining the feedback processes between the flow and clasts, which governs the flow patterns around the clasts, thus directly affecting the depositional patterns of the incoming sediments. To examine the validity of the hypothesis and meet the objectives of this research, 19 detailed experimental runs were conducted in a tilting, water recirculating laboratory flume under well-controlled conditions. A fixed array of clast-obstacles were placed atop a well-packed bed with uniform size glass beads. During the runs, multifractional spherical particles were fed upstream of the clast section at a predetermined rate. State-of-the-art techniques/instruments, such as imaging analysis software, Large Scale Particle Velocimeter (LSPIV) and an Acoustic Doppler Velocimetry (ADV) were employed to provide unique quantitative measurements for bedload fluxes, clast/clusters geomorphic patterns, and mean flow characteristics in the vicinity of the clusters. Different flow patterns were recorded for the high relative submergence (HRS) and low relative submergence (LRS) experimental runs. The ADV measurements provided improved insight about the governing flow mechanisms for the HRS runs. These mechanisms were described with flow upwelling at the center of the flume and downwelling occurring along the flume walls. Flow downwelling corresponded to an increase in the free surface velocity. Additionally, the visual observations made during the sediment transport runs supported the flow findings. For the LRS experimental runs, the near-bed flow structures (HS vortices, Froudian wakes, and hydraulic jumps) controlled the depositional patterns of the incoming sediment. The LSPIV measurements in the LRS case, clearly, indicated distinguishable flow patterns at the free surface; thus implying that the signature of the clasts (roughness) was reflected directly at the free surface. This was not the case for the HRS, where the effects of clasts on the flow were not clearly depicted at the free surface. Lastly, the LSPIV measurements showed that the flow variability in the LRS runs may increase the utility of clasts for creating suitable fish habitats. Overall, the above findings compared favorably with findings of other studies that examined flow behind obstacles, hydraulics of simple habitat structures, and the effects of clusters on the pulsating nature of bedload transport.

  2. RADIOACTIVE WASTE STREAMS FROM VARIOUS POTENTIAL NUCLEAR FUEL CYCLE OPTIONS

    SciTech Connect

    Nick Soelberg; Steve Piet

    2010-11-01

    Five fuel cycle options, about which little is known compared to more commonly known options, have been studied in the past year for the United States Department of Energy. These fuel cycle options, and their features relative to uranium-fueled light water reactor (LWR)-based fuel cycles, include: Advanced once-through reactor concepts (Advanced Once-Through, or AOT) intended for high uranium utilization and long reactor operating life, use depleted uranium in some cases, and avoid or minimize used fuel reprocessing Fission-fusion hybrid (FFH) reactor concepts potential variations are intended for high uranium or thorium utilization, produce fissile material for use in power generating reactors, or transmute transuranic (TRU) and some radioactive fission product (FP) isotopes High temperature gas reactor (HTGR) concepts - intended for high uranium utilization, high reactor thermal efficiencies; they have unique fuel designs Molten salt reactor (MSR) concepts can breed fissile U-233 from Th fuel and avoid or minimize U fuel enrichment, use on-line reprocessing of the used fuel, produce lesser amounts of long-lived, highly radiotoxic TRU elements, and avoid fuel assembly fabrication Thorium/U-233 fueled LWR (Th/U-233) concepts can breed fissile U-233 from Th fuel and avoid or minimize U fuel enrichment, and produce lesser amounts of long-lived, highly radiotoxic TRU elements. These fuel cycle options could result in widely different types and amounts of used or spent fuels, spent reactor core materials, and waste streams from used fuel reprocessing, such as: Highly radioactive, high-burnup used metal, oxide, or inert matrix U and/or Th fuels, clad in Zr, steel, or composite non-metal cladding or coatings Spent radioactive-contaminated graphite, SiC, carbon-carbon-composite, metal, and Be reactor core materials Li-Be-F salts containing U, TRU, Th, and fission products Ranges of separated or un-separated activation products, fission products, and actinides. Waste forms now used or studied for used LWR fuels can be used for some of these waste streams but some waste forms may need to be developed for unique waste streams.

  3. Effects of unsteady free-stream velocity and free-stream turbulence at a stagnation point

    NASA Technical Reports Server (NTRS)

    Gorla, R. S. R.

    1982-01-01

    The combined effects of transient free stream velocity and turbulence at a stagnation point on a cylinder situated in a crossflow is investigated analytically, and a model is formulated for the eddy diffusivity induced by free-stream turbulence. The steepest descent method is used to integrate the governing momentum expression, and numerical solutions are given for the unsteady wall shear stress function for specific free-stream transients. It is found after correlation of the results by means of a new turbulence parameter that wall friction increases with increasing free-stream turbulence intensity, and that the friction factor increases with increasing reduced frequency of oscillation values.

  4. Web-Streamed Didactic Instruction on Substance Use Disorders Compares Favorably with Live-Lecture Format

    ERIC Educational Resources Information Center

    Maher, Karam-Hage; Brower, Kirk J.; Mullan, Patricia B.; Gay, Tamara; Gruppen, Larry D.

    2013-01-01

    Objective: Education about substance use disorders in medical schools and, subsequently, physicians' identification of and intervention in these diagnoses lag behind that of most other disabling disorders. To reduce barriers and improve access to education about this major public health concern, medical schools are increasingly adopting web-based…

  5. Live-streaming: Time-lapse video evidence of novel streamer formation mechanism and varying viscosity.

    PubMed

    Parvinzadeh Gashti, Mazeyar; Bellavance, Julien; Kroukamp, Otini; Wolfaardt, Gideon; Taghavi, Seyed Mohammad; Greener, Jesse

    2015-07-01

    Time-lapse videos of growing biofilms were analyzed using a background subtraction method, which removed camouflaging effects from the heterogeneous field of view to reveal evidence of streamer formation from optically dense biofilm segments. In addition, quantitative measurements of biofilm velocity and optical density, combined with mathematical modeling, demonstrated that streamer formation occurred from mature, high-viscosity biofilms. We propose a streamer formation mechanism by sudden partial detachment, as opposed to continuous elongation as observed in other microfluidic studies. Additionally, streamer formation occurred in straight microchannels, as opposed to serpentine or pseudo-porous channels, as previously reported. PMID:26339304

  6. Web-Streamed Didactic Instruction on Substance Use Disorders Compares Favorably with Live-Lecture Format

    ERIC Educational Resources Information Center

    Maher, Karam-Hage; Brower, Kirk J.; Mullan, Patricia B.; Gay, Tamara; Gruppen, Larry D.

    2013-01-01

    Objective: Education about substance use disorders in medical schools and, subsequently, physicians' identification of and intervention in these diagnoses lag behind that of most other disabling disorders. To reduce barriers and improve access to education about this major public health concern, medical schools are increasingly adopting web-based

  7. Predator avoidance during reproduction: diel movements by spawning sockeye salmon between stream and lake habitats.

    PubMed

    Bentley, Kale T; Schindler, Daniel E; Cline, Timothy J; Armstrong, Jonathan B; Macias, Daniel; Ciepiela, Lindsy R; Hilborn, Ray

    2014-11-01

    Daily movements of mobile organisms between habitats in response to changing trade-offs between predation risk and foraging gains are well established; however, less in known about whether similar tactics are used during reproduction, a time period when many organisms are particularly vulnerable to predators. We investigated the reproductive behaviour of adult sockeye salmon (Oncorhynchus nerka) and the activity of their principal predator, brown bears (Ursus arctos), on streams in south-western Alaska. Specifically, we continuously monitored movements of salmon between lake habitat, where salmon are invulnerable to bears, and three small streams, where salmon spawn and are highly vulnerable to bears. We conducted our study across 2 years that offered a distinct contrast in bear activity and predation rates. Diel movements by adult sockeye salmon between stream and lake habitat were observed in 51.3% ± 17.7% (mean ± SD) of individuals among years and sites. Fish that moved tended to hold in the lake for most of the day and then migrated into spawning streams during the night, coincident with when bear activity on streams tended to be lowest. Additionally, cyclic movements between lakes and spawning streams were concentrated earlier in the spawning season. Individuals that exhibited diel movements had longer average reproductive life spans than those who made only one directed movement into a stream. However, the relative effect was dependent on the timing of bear predation, which varied between years. When predation pressure primarily occurred early in the spawning run (i.e., during the height of the diel movements), movers lived 120-310% longer than non-movers. If predation pressure was concentrated later in the spawning run (i.e. when most movements had ceased), movers only lived 10-60% longer. Our results suggest a dynamic trade-off in reproductive strategies of sockeye salmon; adults must be in the stream to reproduce, but must also avoid predation long enough to spawn. Given the interannual variation in the timing and intensity of predation pressure, the advantages of a particular movement strategy will likely vary among years. Regardless, movements by salmon allowed individuals to exploit fine-scale habitat heterogeneity during reproduction, which appears to be a strategy to reduce predation risk on the spawning grounds. PMID:24702169

  8. Recovery of three arctic stream reaches from experimental nutrient enrichment

    USGS Publications Warehouse

    Benstead, J.P.; Green, A.C.; Deegan, Linda A.; Peterson, B.J.; Slavik, K.; Bowden, W.B.; Hershey, A.E.

    2007-01-01

    1. Nutrient enrichment and resulting eutrophication is a widespread anthropogenic influence on freshwater ecosystems, but recovery from nutrient enrichment is poorly understood, especially in stream environments. We examined multi-year patterns in community recovery from experimental low-concentration nutrient enrichment (N + P or P only) in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (U.S.A.). 2. Rates of recovery varied among community components and depended on duration of enrichment (2-13 consecutive growing seasons). Biomass of epilithic algae returned to reference levels rapidly (within 2 years), regardless of nutrients added or enrichment duration. Aquatic bryophyte cover, which increased greatly in the Kuparuk River only after long-term enrichment (8 years), took 8 years of recovery to approach reference levels, after storms had scoured most remnant moss in the recovering reach. 3. Multi-year persistence of bryophytes in the Kuparuk River appeared to prevent recovery of insect populations that had either been positively (e.g. the mayfly Ephemerella, most chironomid midge taxa) or negatively (e.g. the tube-building chironomid Orthocladius rivulorum) affected by this shift in dominant primary producer. These lags in recovery (of >3 years) were probably driven by the persistent effect of bryophytes on physical benthic habitat. 4. Summer growth rates of Arctic grayling (both adults and young-of-year) in Oksrukuyik Creek (fertilised for 6 years with no bryophyte colonisation), which were consistently increased by nutrient addition, returned to reference rates within 1-2 years. 5. Rates of recovery of these virtually pristine Arctic stream ecosystems from low-level nutrient enrichment appeared to be controlled largely by duration of enrichment, mediated through physical habitat shifts caused by eventual bryophyte colonisation, and subsequent physical disturbance that removed bryophytes. Nutrient enrichment of oligotrophic Arctic stream ecosystems caused by climate change or local anthropogenic activity may have dramatic and persistent consequences if it results in the colonisation of long-lived primary producers that alter physical habitat. ?? 2007 The Authors.

  9. Resource synergy in stream periphyton communities

    SciTech Connect

    Hill, Walter; Fanta, S.E.; Roberts, Brian J; Francoeur, Steven N.

    2011-03-01

    1. Light and nutrients play pivotal roles in determining the growth of autotrophs, yet the potential for synergistic interactions between the two resources in algal communities is poorly understood, especially in stream ecosystems. In this study, light and phosphorus were manipulated in large experimental streams to examine resource colimitation and synergy in stream periphyton. 2. Whole-stream metabolism was simultaneously limited by light and phosphorus. Increasing the supply of either light or phosphorus resulted in significant increases in primary production and the transformation of the streams from heterotrophy to autotrophy. 3. Resource-driven changes in periphyton community structure occurred in concert with changes in production. Algal assemblages in highly shaded streams were composed primarily of small diatoms such as Achnanthidium minutissima, whereas larger diatoms such as Melosira varians predominated at higher irradiances. Phosphorus enrichment had relatively little effect on assemblage structure, but it did substantially diminish the abundance of Meridion circulare, a diatom whose mucilaginous colonies were conspicuously abundant in phosphorus-poor, high-light streams. Bacterial biomass declined relative to algal biomass with increases in primary productivity, regardless of whether the increases were caused by light or phosphorus. 4. Synergistic effects on primary production appeared to occur because the availability of one resource facilitated the utilization of the other. Light increased the abundance of large diatoms, which are known to convert high concentrations of nutrients into primary production more effectively than smaller taxa. Phosphorus enrichment led to the replacement of Meridion circulare by non-mucilaginous taxa in phosphorus-enriched streams, and we hypothesize that this change enabled more efficient use of light in photosynthesis. Higher ratios of chlorophyll a : biomass in phosphorus-enriched streams may have also led to more efficient photon capture and higher photosynthetic rates. 5.Synthesis. Our results underscore the potential for resource colimitation, even in habitats where a single resource is as strongly limiting as is light in shaded streams. The capacity of autotrophic communities to respond to more than one limiting resource suggests that prevailing single-resource models of ecosystem productivity are overly simplistic.

  10. Toward living radical polymerization.

    PubMed

    Moad, Graeme; Rizzardo, Ezio; Thang, San H

    2008-09-01

    Radical polymerization is one of the most widely used processes for the commercial production of high-molecular-weight polymers. The main factors responsible for the preeminent position of radical polymerization are the ability to polymerize a wide array of monomers, tolerance of unprotected functionality in monomer and solvent, and compatibility with a variety of reaction conditions. Radical polymerization is simple to implement and inexpensive in relation to competitive technologies. However, conventional radical polymerization severely limits the degree of control that researchers can assert over molecular-weight distribution, copolymer composition, and macromolecular architecture. This Account focuses on nitroxide-mediated polymerization (NMP) and polymerization with reversible addition-fragmentation chain transfer (RAFT), two of the more successful approaches for controlling radical polymerization. These processes illustrate two distinct mechanisms for conferring living characteristics on radical polymerization: reversible deactivation (in NMP) and reversible or degenerate chain transfer (in RAFT). We devised NMP in the early 1980s and have exploited this method extensively for the synthesis of styrenic and acrylic polymers. The technique has undergone significant evolution since that time. New nitroxides have led to faster polymerization rates at lower temperatures. However, NMP is only applicable to a restricted range of monomers. RAFT was also developed at CSIRO and has proven both more robust and more versatile. It is applicable to the majority of monomers subject to radical polymerization, but the success of the polymerization depends upon the selection of the RAFT agent for the monomers and reaction conditions. We and other groups have proposed guidelines for selection, and the polymerization of most monomers can be well-controlled to provide minimal retardation and a high fraction of living chains by using one of just two RAFT agents. For example, a tertiary cyanoalkyl trithiocarbonate is suited to (meth)acrylate, (meth)acrylamide, and styrenic monomers, while a cyanomethyl xanthate or dithiocarbamate works with vinyl monomers, such as vinyl acetate or N-vinylpyrrolidone. With the appropriate choice of reagents and polymerization conditions, these reactions possess most of the attributes of living polymerization. We have used these methods in the synthesis of well-defined homo-, gradient, diblock, triblock, and star polymers and more complex architectures, including microgels and polymer brushes. Applications of these polymers include novel surfactants, dispersants, coatings and adhesives, biomaterials, membranes, drug-delivery media, electroactive materials, and other nanomaterials. PMID:18700787

  11. Live From the Poles

    NASA Astrophysics Data System (ADS)

    Linder, C. A.; Kent, J.; Lippsett, L.

    2006-12-01

    International Polar Year presents an extraordinary opportunity to educate students and the public about science at the icy ends of the Earth. The goal of our proposal is to apply collaborative multimedia approaches to bring the story of four polar research expeditions to the general public and the classroom. The four expeditions (measurement of ice sheet dynamics in Greenland, a study of the McMurdo ecosystem over austral winter, installation of a buoy array in the Beaufort Gyre, and exploration of the Gakkel Ridge) were chosen based on their broad range of disciplines and relevance to the three primary IPY research emphasis areas defined by NSF. A science writer and a professional photographer will join each expedition and file dispatches for a daily Webcast. The posting will feature science updates, logistical challenges, team member profiles, and life at sea (or on the ice). The writer will also coordinate real-time phone patches from PIs in the field to audiences at the Museum of Science, Boston, the Smithsonian National Museum of Natural History, The Field Museum, Chicago, the Houston Museum of Natural Science, the Birch Aquarium, San Diego, the Pacific Science Center, Seattle, National Public Radio "Talk of the Nation: Science Friday," CBS News, and to student "reporters" writing for Scholastic Online. At the museums, the "Live from the Ice" interactive phone calls will be preceded by a background presentation by a scientist, who will also moderate the live discussion between the public and researchers in the field. A 20-30 minute satellite phone call will allow the public to ask the researchers questions about their research while it's happening. In addition to building and promoting an online experience, a museum exhibit featuring models of Arctic instruments and informative kiosks will be developed at the Woods Hole Oceanographic Institution Exhibit Center. Each of our partner museums will also provide a "leave-behind" component to continue to educate visitors before and after the live talks. This project will bring the remote Polar Regions and the scientists that are studying them to audiences across the United States.

  12. URBAN STREAM BURIAL INCREASES WATERSHED-SCALE NITRATE EXPORT

    EPA Science Inventory

    Nitrogen (N) uptake in streams is an important ecosystem service that may be affected by the widespread burial of streams in stormwater pipes in urban watersheds. We predicted that stream burial reduces the capacity of streams to remove nitrate (NO3-) from the water column by in...

  13. THE USE OF GEOMORPHOLOGICAL CLASSIFICATION FOR RISK MANAGEMENT OF STREAMS

    EPA Science Inventory

    Changes in the amount and types of land use in a watershed can destabilize stream channel structure, increase sediment loading and degrade in-stream habitat. Stream classification systems (e.g., Rosgen) may be useful for determining the susceptibility of stream channel segments t...

  14. Toward a Neurophysiological Theory of Auditory Stream Segregation

    ERIC Educational Resources Information Center

    Snyder, Joel S.; Alain, Claude

    2007-01-01

    Auditory stream segregation (or streaming) is a phenomenon in which 2 or more repeating sounds differing in at least 1 acoustic attribute are perceived as 2 or more separate sound sources (i.e., streams). This article selectively reviews psychophysical and computational studies of streaming and comprehensively reviews more recent…

  15. 40 CFR 434.61 - Commingling of waste streams.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Commingling of waste streams. 434.61... STANDARDS Miscellaneous Provisions 434.61 Commingling of waste streams. Where waste streams from any facility covered by this part are combined for treatment or discharge with waste streams from...

  16. 40 CFR 434.61 - Commingling of waste streams.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Commingling of waste streams. 434.61... PERFORMANCE STANDARDS Miscellaneous Provisions 434.61 Commingling of waste streams. Where waste streams from any facility covered by this part are combined for treatment or discharge with waste streams...

  17. 40 CFR 434.61 - Commingling of waste streams.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Commingling of waste streams. 434.61... STANDARDS Miscellaneous Provisions 434.61 Commingling of waste streams. Where waste streams from any facility covered by this part are combined for treatment or discharge with waste streams from...

  18. 40 CFR 434.61 - Commingling of waste streams.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Commingling of waste streams. 434.61... PERFORMANCE STANDARDS Miscellaneous Provisions 434.61 Commingling of waste streams. Where waste streams from any facility covered by this part are combined for treatment or discharge with waste streams...

  19. Adaptation Reveals Multiple Levels of Representation in Auditory Stream Segregation

    ERIC Educational Resources Information Center

    Snyder, Joel S.; Carter, Olivia L.; Hannon, Erin E.; Alain, Claude

    2009-01-01

    When presented with alternating low and high tones, listeners are more likely to perceive 2 separate streams of tones ("streaming") than a single coherent stream when the frequency separation ([delta]f) between tones is greater and the number of tone presentations is greater ("buildup"). However, the same large-[delta]f sequence reduces streaming

  20. RIPARIAN FOREST INDICATORS OF POTENTIAL FUTURE STREAM CONDITION

    EPA Science Inventory

    Large wood in streams can play an extraordinarily important role in influencing the physical structure of streams and in providing habitat for aquatic organisms. Since wood is continually lost from streams, predicting the future input of wood to streams from riparian forests is c...

  1. Freezing of living cells

    SciTech Connect

    Mazur, P.

    1985-01-01

    It can be calculated that a living cell will survive more than 5000 years at -196/sup 0/C. This ability to essentially stop biological time has important implications in medicine and agriculture, and in biological research. In medicine the chief implications are in the banking of transplantable tissues and organs and in in vitro fertilization. In agriculture the applications stem in part from the role of frozen embryos in amplifying the number of calves produced by high quanlity cows. The problem is how can cells survive both the cooling to such very low temperatures and the return to normal temperatures. The answers involve fundamental characteristics of cells such as the permeability of their surface membranes to water and solutes. These characteristics determine whether or not cells undergo lethal internal ice formation and other response during freezing and thawing. 27 refs., 12 figs.

  2. Living With Semantic Dementia

    PubMed Central

    Sage, Karen; Wilkinson, Ray; Keady, John

    2014-01-01

    Semantic dementia is a variant of frontotemporal dementia and is a recently recognized diagnostic condition. There has been some research quantitatively examining care partner stress and burden in frontotemporal dementia. There are, however, few studies exploring the subjective experiences of family members caring for those with frontotemporal dementia. Increased knowledge of such experiences would allow service providers to tailor intervention, support, and information better. We used a case study design, with thematic narrative analysis applied to interview data, to describe the experiences of a wife and son caring for a husband/father with semantic dementia. Using this approach, we identified four themes: (a) living with routines, (b) policing and protecting, (c) making connections, and (d) being adaptive and flexible. Each of these themes were shared and extended, with the importance of routines in everyday life highlighted. The implications for policy, practice, and research are discussed. PMID:24532121

  3. Living on the edge.

    PubMed

    Hinrichsen, D

    1989-01-01

    A brief update on the destruction of the environment is given. The concern is for the coastal waters and rivers which are polluted daily by raw sewage, industrial waste, and sedimentation, e.g., the Juru in Malaysia, the Pasig in the Philippines, and the Chao Phraya in Thailand are open sewers by the time the rivers reach the sea or bay. Metropolitan Manila's river is said to be biologically dead from pollution, and the bays of Manila and Jakarta suffer from oxygen depletion. Unfortunately, the coastal area maintains population as well as the wealth of marine life. In the US in 1990, 75% of the population will live within 50 miles of a shore including the Great Lakes. 30 southeast Asia's 50 largest cities are located on or near a coast. Over fishing, over population, over developing, and over exploitation are unacceptable; the alternative is for man to correct his mistakes. PMID:12285899

  4. Acidic stream mitigation by limestone sand addition

    SciTech Connect

    Brant, D.L.; Marich, A.J. Jr.; Largent, K.L.

    1996-12-31

    The Town Line Run watershed comprises an area of 3,600 wooded acres. The tributaries feeding the stream consist of sandstone springs that do not contribute alkalinity to the watershed, leaving the stream susceptible to acid precipitation. This has a negative affect on Iser`s Run, a native brook trout fishery above the confluence with Town Line Run. The objective in stream liming is to improve water chemistry by increasing pH, alkalinity, and reducing acidity, aluminum, and iron. Introducing crushed limestone directly into a stream from a dump truck is an inexpensive but temporary solution to accomplish this objective. In this type of liming operation, a bed of limestone is spread down the stream channel by the momentum of the stream from the introduction point, rather than manually. Water moving across this bed dissolves the limestone, increasing the pH, alkalinity, and calcium while decreasing the acidity, iron, and aluminum concentrations of the water. The size of the limestone particles is important for this purpose because particles that are too small (<150 microns) will carried away, while particles that are too large (>1000 microns) will remain at the introduction point. Our study placed 80 tons of sand-sized limestone (85% calcite) in the stream channel at a single point. Water samples were collected monthly at the following sites (1) directly upstream of the addition site, (2) 100 yards downstream of the site, and (3) 2500 yards downstream of the site. Other sample locations include (4) upstream and (5) downstream of the Town Line Run- Iser`s Run confluence and the Casselman River upstream (6) and downstream (7) of Town Line Run. The samples were analyzed for pH. Specific conductivity, Alkalinity, Acidity, Iron, Manganese, Aluminum, and Sulfate.

  5. Influences of wildfire and channel reorganization on spatial and temporal variation in stream temperature and the distribution of fish and amphibians

    USGS Publications Warehouse

    Dunham, J.B.; Rosenberger, A.E.; Luce, C.H.; Rieman, B.E.

    2007-01-01

    Wildfire can influence a variety of stream ecosystem properties. We studied stream temperatures in relation to wildfire in small streams in the Boise River Basin, located in central Idaho, USA. To examine the spatio-temporal aspects of temperature in relation to wildfire, we employed three approaches: a pre-post fire comparison of temperatures between two sites (one from a burned stream and one unburned) over 13 years, a short-term (3 year) pre-post fire comparison of a burned and unburned stream with spatially extensive data, and a short-term (1 year) comparative study of spatial variability in temperatures using a "space for time" substitutive design across 90 sites in nine streams (retrospective comparative study). The latter design included streams with a history of stand-replacing wildfire and streams with severe post-fire reorganization of channels due to debris flows and flooding. Results from these three studies indicated that summer maximum water temperatures can remain significantly elevated for at least a decade following wildfire, particularly in streams with severe channel reorganization. In the retrospective comparative study we investigated occurrence of native rainbow trout (Oncorhynchus mykiss) and tailed frog larvae (Ascaphus montanus) in relation to maximum stream temperatures during summer. Both occurred in nearly every site sampled, but tailed frog larvae were found in much warmer water than previously reported in the field (26.6??C maximum summer temperature). Our results show that physical stream habitats can remain altered (for example, increased temperature) for many years following wildfire, but that native aquatic vertebrates can be resilient. In a management context, this suggests wildfire may be less of a threat to native species than human influences that alter the capacity of stream-living vertebrates to persist in the face of natural disturbance. ?? 2007 Springer Science+Business Media, LLC.

  6. EFFECTS OF STREAM RESTORATION ON IN-STREAM WATER QUALITY IN AN URBAN WATERSHED

    EPA Science Inventory

    The purpose of this on-going project is to provide information to Municipal Separate Storm Sewer System (MS4s) operators and states on the performance of selected best management practices (BMPs), specifically, stream restoration techniques, on improving biological and in-stream ...

  7. Statistical model of meteor streams. IV - A study of radio streams from the synoptic year

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1976-01-01

    The paper gives a detailed description of a search procedure for radio meteor streams and reports the detection of 275 streams in a synoptic-year sample of 19,698 radio meteors observed by the radar system of the Radio Meteor Project at Havana, Illinois. The orbital elements and related parameters of the detected streams are presented, the two parameters of the D-distribution of the streams are determined, and their mean radiants are plotted. Possible associations between the streams and possible parent objects are identified; it is found that streams may be associated with seven periodic comets, five other comets, at least nine asteroids (especially Adonis), and several fireballs. The mean space density in the streams is found to be much lower than the sporadic density, although the central density may be considerably greater than the sporadic density. It is shown that the derived absolute stream-density values are in agreement with the order of magnitude of the space densities estimated from cometary production rates for solid material of comparable particle size.

  8. Grazing management effects on stream bank erosion and phosphorus delivery to a pasture stream

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pasture lands may deliver significant sediment and phosphorus (P) to surface waters. To determine the effects of beef (Bos taurus) grazing practices on stream bank erosion and P losses, three treatments [rotational stocking (RS), continuous stocking with restricted stream access (CSR), and continuou...

  9. Modeling Fluvial Response to In-stream Woody Vegetation: Implications for Stream Corridor Restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    River restoration and bank stabilization programs often use vegetation for improving stream corridor habitat, aesthetic, and function. Yet no study has examined the use of managed vegetation plantings to transform a straight, degraded stream corridor into a more functional, aesthetically-pleasing m...

  10. The role of remediation, natural alkalinity sources and physical stream parameters in stream recovery.

    PubMed

    Kruse, Natalie A; DeRose, Lisa; Korenowsky, Rebekah; Bowman, Jennifer R; Lopez, Dina; Johnson, Kelly; Rankin, Edward

    2013-10-15

    Acid mine drainage (AMD) negatively impacts not only stream chemistry, but also aquatic biology. The ultimate goal of AMD treatment is restoration of the biological community, but that goal is rarely explicit in treatment system design. Hewett Fork in Raccoon Creek Watershed, Ohio, has been impacted by historic coal mining and has been treated with a calcium oxide doser in the headwaters of the watershed since 2004. All of the acidic inputs are isolated to a 1.5 km stretch of stream in the headwaters of the Hewett Fork watershed. The macroinvertebrate and fish communities have begun to recover and it is possible to distinguish three zones downstream of the doser: an impaired zone, a transition zone and a recovered zone. Alkalinity from both the doser and natural sources and physical stream parameters play a role in stream restoration. In Hewett Fork, natural alkaline additions downstream are higher than those from the doser. Both, alkaline additions and stream velocity drive sediment and metal deposition. Metal deposition occurs in several patterns; aluminum tends to deposit in regions of low stream velocity, while iron tends to deposit once sufficient alkalinity is added to the system downstream of mining inputs. The majority of metal deposition occurs upstream of the recovered zone. Both the physical stream parameters and natural alkalinity sources influence biological recovery in treated AMD streams and should be considered in remediation plans. PMID:23895912

  11. DIATOM SPECIES RICHNESS IN STREAMS OF THE EASTERN US: STREAM SIZE AND HABITAT EFFECTS

    EPA Science Inventory

    We analyzed the relationship between benthic diatom assemblages, stream size, and habitat characteristics in 445 first through seventh order streams in the Mid-Atlantic (n=230), South Atlantic (n=61), Ohio (n=140), and Tennessee (n=14) hydrologic regions. Diatom samples were col...

  12. Streaming Media Seminar--Effective Development and Distribution of Streaming Multimedia in Education

    ERIC Educational Resources Information Center

    Mainhart, Robert; Gerraughty, James; Anderson, Kristine M.

    2004-01-01

    Concisely defined, "streaming media" is moving video and/or audio transmitted over the Internet for immediate viewing/listening by an end user. However, at Saint Francis University's Center of Excellence for Remote and Medically Under-Served Areas (CERMUSA), streaming media is approached from a broader perspective. The working definition includes

  13. Comparing Streaming Video and Videotapes: Can Streaming Video Convey Affective Meaning as Well as Videotape?

    ERIC Educational Resources Information Center

    Cofield, Jay L.

    This study investigated whether or not low-bandwidth streaming video could be useful for affective purposes. A group of 30 students in a cinema course at a public, liberal arts university viewed a 10-minute dramatic video scene by either videotape or low-bandwidth streaming video. They also took a survey to determine their affective responses and

  14. Streaming in Flemish Secondary Schools: Exploring Teachers' Perceptions of and Adaptations to Students in Different Streams

    ERIC Educational Resources Information Center

    Stevens, Peter A. J.; Vermeersch, Hans

    2010-01-01

    A rich body of research on streaming or tracking conducted mainly in the USA and UK suggests that teachers have lower expectations of students in lower education streams and adapt their curriculum and pedagogy in line with such expectations. Recent large-scale quantitative research conducted in Flanders (Belgium) shows that teachers teaching in

  15. Imaging and analysis of mitochondrial dynamics in living cells.

    PubMed

    Ekanayake, Sanjaya B; El Zawily, Amr M; Paszkiewicz, Gal; Rolland, Aurlia; Logan, David C

    2015-01-01

    One of the most striking features of plant mitochondria when visualized in living tissue is their dynamism. The beauty of cytoplasmic streaming, driving, and being driven by the motility of mitochondria and other small organelles belies the complexity of the process. Equally, capturing that dynamism and investigating the genes, proteins, and mechanisms underpinning the processes using molecular cell biology and bioimaging is a complex process. It requires the generation of fluorescent protein constructs, stable transgenic plants sometimes expressing multiple fusions, and generation of mutants, even before one is ready for analytical experimentation. Here, we describe some of the key tools and methods necessary to investigate plant mitochondrial dynamics. PMID:25910738

  16. Jet Noise Scaling in Dual Stream Nozzles

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas; Bridges, James

    2010-01-01

    Power spectral laws in dual stream jets are studied by considering such flows a superposition of appropriate single-stream coaxial jets. Noise generation in each mixing region is modeled using spectral power laws developed earlier for single stream jets as a function of jet temperature and observer angle. Similarity arguments indicate that jet noise in dual stream nozzles may be considered as a composite of four single stream jets representing primary/secondary, secondary/ambient, transition, and fully mixed zones. Frequency filter are designed to highlight spectral contribution from each jet. Predictions are provided at an area ratio of 2.0--bypass ratio from 0.80 to 3.40, and are compared with measurements within a wide range of velocity and temperature ratios. These models suggest that the low frequency noise in unheated jets is dominated by the fully mixed region at all velocity ratios, while the high frequency noise is dominated by the secondary when the velocity ratio is larger than 0.80. Transition and fully mixed jets equally dominate the low frequency noise in heated jets. At velocity ratios less than 0.50, the high frequency noise from primary/bypass becomes a significant contributing factor similar to that in the secondary/ambient jet.

  17. Plant genes link forests and streams

    NASA Astrophysics Data System (ADS)

    Leroy, C. J.; Whitham, T. G.; Keim, P.; Marks, J. C.

    2005-05-01

    Recent terrestrial research demonstrates the importance of genetic variation within tree species such as oaks, aspen and cottonwoods in affecting the function of forest ecosystems. We show similarly that genetic variation within cottonwoods can affect stream ecosystem function through litterfall. The genetic makeup of cottonwood leaf litter directly affects in-stream leaf decomposition rates, aquatic fungal accumulation and macroinvertebrate assemblages. This genetic variation is especially important in the western United States because cottonwoods are a dominant riparian tree and are currently in dramatic decline. In western rivers, cottonwood genetic diversity may be elevated due to naturally-occurring hybridization zones. We collected litter from five genotypes of each of four cottonwood cross types from common garden trees and measured decomposition rates using litterbag techniques in the Weber River (UT). Among the cottonwood genotypes decomposition rates ranged on average from 0.0077 0.0003 day-1 for backcross to P. angustifolia hybrids to 0.0105 0.0003 day-1 for P. fremontii. Similar and substantial differences among F1 and backcross hybrids provide evidence for genetic control over in-stream decomposition rates. Prior studies have shown that species diversity influences litter quality and stream function. This study extends this by linking genetic diversity to stream ecosystem function.

  18. Microbial biodiversity in glacier-fed streams

    PubMed Central

    Wilhelm, Linda; Singer, Gabriel A; Fasching, Christina; Battin, Tom J; Besemer, Katharina

    2013-01-01

    While glaciers become increasingly recognised as a habitat for diverse and active microbial communities, effects of their climate change-induced retreat on the microbial ecology of glacier-fed streams remain elusive. Understanding the effect of climate change on microorganisms in these ecosystems is crucial given that microbial biofilms control numerous stream ecosystem processes with potential implications for downstream biodiversity and biogeochemistry. Here, using a space-for-time substitution approach across 26 Alpine glaciers, we show how microbial community composition and diversity, based on 454-pyrosequencing of the 16S rRNA gene, in biofilms of glacier-fed streams may change as glaciers recede. Variations in streamwater geochemistry correlated with biofilm community composition, even at the phylum level. The most dominant phyla detected in glacial habitats were Proteobacteria, Bacteroidetes, Actinobacteria and Cyanobacteria/chloroplasts. Microorganisms from ice had the lowest ? diversity and contributed marginally to biofilm and streamwater community composition. Rather, streamwater apparently collected microorganisms from various glacial and non-glacial sources forming the upstream metacommunity, thereby achieving the highest ? diversity. Biofilms in the glacier-fed streams had intermediate ? diversity and species sorting by local environmental conditions likely shaped their community composition. ? diversity of streamwater and biofilm communities decreased with elevation, possibly reflecting less diverse sources of microorganisms upstream in the catchment. In contrast, ? diversity of biofilms decreased with increasing streamwater temperature, suggesting that glacier retreat may contribute to the homogenisation of microbial communities among glacier-fed streams. PMID:23486246

  19. The Magellanic Stream and the Dual Proposal

    NASA Astrophysics Data System (ADS)

    Bartlett, David F.

    2008-05-01

    Recently Nidever, Majewski, and Burton have used the Leiden-Argentine-Bonn all-sky HI survey to make a thorough study of the Magellanic Stream. In distinction to previous work, they now find that all of the stream and much of the leading arm originates in an Overdensity Region that includes the very luminous emission nebula 30 Doradus. Outstanding remaining questions: 1)Why doesn't the Magellanic stream have stars? and 2) Are magnetic fields responsible for maintaining the stream's strongly periodic spatial and velocity patterns? The Dual Proposal[1] can provide answers. Here the photon has a real mass and the graviton an imaginary one, both masses given by mc2=hc/?o = 10-25 eV, where ?o = 400 pc. The resulting sinusoidal gravitational potential (? = - (GM/r) Cos[kor], ko=2?/?o) has a unique feature: maxima of potential where gas can stall and create stars. The massive photon generalizes Maxwell's stress tensor by adding terms in the vector potential A (Chibisov 1976). For scales greater than 400 pc, even weak B-fields can have a strong influence on the plasma within the stream. Finally the new universal scale ?o may, someday, relate gravitation to atomic physics. By equating inertial and gravitational energy densities, one finds a numerical relationship: c4ko2/2?G = 13.6 eV/(137ao)3, where ao is the Bohr radius. Ref [1]: "Analogies between electricity and gravity", Metrologia 41 (2004) S115-S124..

  20. High-acuity spatial stream segregation.

    PubMed

    Middlebrooks, John C

    2013-01-01

    In a complex auditory scene, location in space is one of several acoustic features that permit listeners to segregate competing sequences of sounds into discrete perceptual streams. Nevertheless, the spatial acuity of stream segregation is unknown. Moreover, it is not clear whether this is really a spatial effect or whether it reflects a binaural process that only indirectly involves space. We employed "rhythmic masking release" as an objective measure of spatial stream segregation. That task revealed spatial acuity nearly as fine as listeners' discriminations of static locations (i.e., their minimum audible angles). Tests using low-pass, high-pass, and varying-level conditions in the horizontal dimension demonstrated that binaural difference cues provide finer acuity than does any monaural cue and that low-frequency interaural delay cues give finer acuity than do high-frequency interaural level differences. Surprisingly, stream segregation in the vertical dimension, where binaural difference cues are negligible, could be nearly as acute as that in the horizontal dimension. The results show a common spatial underpinning to performance. Nevertheless, a dissociation across conditions between localization acuity and masking-release thresholds suggests that spatial stream segregation is accomplished by brain systems discrete from those responsible for sound-localization judgments. PMID:23716256

  1. Microbial biodiversity in glacier-fed streams.

    PubMed

    Wilhelm, Linda; Singer, Gabriel A; Fasching, Christina; Battin, Tom J; Besemer, Katharina

    2013-08-01

    While glaciers become increasingly recognised as a habitat for diverse and active microbial communities, effects of their climate change-induced retreat on the microbial ecology of glacier-fed streams remain elusive. Understanding the effect of climate change on microorganisms in these ecosystems is crucial given that microbial biofilms control numerous stream ecosystem processes with potential implications for downstream biodiversity and biogeochemistry. Here, using a space-for-time substitution approach across 26 Alpine glaciers, we show how microbial community composition and diversity, based on 454-pyrosequencing of the 16S rRNA gene, in biofilms of glacier-fed streams may change as glaciers recede. Variations in streamwater geochemistry correlated with biofilm community composition, even at the phylum level. The most dominant phyla detected in glacial habitats were Proteobacteria, Bacteroidetes, Actinobacteria and Cyanobacteria/chloroplasts. Microorganisms from ice had the lowest ? diversity and contributed marginally to biofilm and streamwater community composition. Rather, streamwater apparently collected microorganisms from various glacial and non-glacial sources forming the upstream metacommunity, thereby achieving the highest ? diversity. Biofilms in the glacier-fed streams had intermediate ? diversity and species sorting by local environmental conditions likely shaped their community composition. ? diversity of streamwater and biofilm communities decreased with elevation, possibly reflecting less diverse sources of microorganisms upstream in the catchment. In contrast, ? diversity of biofilms decreased with increasing streamwater temperature, suggesting that glacier retreat may contribute to the homogenisation of microbial communities among glacier-fed streams. PMID:23486246

  2. Online Feature Extraction Algorithms for Data Streams

    NASA Astrophysics Data System (ADS)

    Ozawa, Seiichi

    Along with the development of the network technology and high-performance small devices such as surveillance cameras and smart phones, various kinds of multimodal information (texts, images, sound, etc.) are captured real-time and shared among systems through networks. Such information is given to a system as a stream of data. In a person identification system based on face recognition, for example, image frames of a face are captured by a video camera and given to the system for an identification purpose. Those face images are considered as a stream of data. Therefore, in order to identify a person more accurately under realistic environments, a high-performance feature extraction method for streaming data, which can be autonomously adapted to the change of data distributions, is solicited. In this review paper, we discuss a recent trend on online feature extraction for streaming data. There have been proposed a variety of feature extraction methods for streaming data recently. Due to the space limitation, we here focus on the incremental principal component analysis.

  3. Roughness coefficients for stream channels in Arizona

    USGS Publications Warehouse

    Aldridge, B.N.; Garrett, J.M.

    1973-01-01

    n in which V = mean cross-sectional velocity of flow, in feet per second; R = hydraulic radius at a cross section, which is the cross-sectional area divided by the wetter perimeter, in feet; Se = energy slope; and n = coefficient of roughness. Many research studies have been made to determine "n" values for open-channel flow (Carter and others, 1963). Guidelines for selecting coefficient of roughness for stream channels are given in most of the literature of stream-channel hydraulics, but few of the data relate directly to streams of Arizona, The U.S> Geological Survey, at the request of the Arizona Highway Department, assembled the color photographs and tables of the Manning "n" values in this report to aid highway engineers in the selection of roughness coefficients for Arizona streams. Most of the photographs show channel reaches for which values of "n" have been assigned by experienced Survey personnel; a few photographs are included for reaches where "n" values have been verified. Verified "n" values are computed from a known discharge and measured channel geometry. Selected photographs of stream channels for which "n" values have been verified are included in U.S. Geological Survey Water-Supply Paper 1849 (Barnes, 1967); stereoscopic slides of Barnes' (1967) photographs and additional photographs can be inspected at U.S> Geological Survey offices in: 2555 E. First Street, Tucson; and 5017 Federal Building, 230 N. First Avenue, Phoenix.

  4. Two-stream modeling of plasmaspheric refilling

    NASA Technical Reports Server (NTRS)

    Guiter, S. M.; Gombosi, T. I.; Rasmussen, C. E.

    1995-01-01

    Plasmaspheric refilling on an L = 4 flux tube was studied by using a time-dependent, hydrodynamic plasmaspheric flow model in which the ion streams from the two hemispheres are treated as distinct fluids. In the model the continuity, momentum, and energy equations of a two-ion (O(+) and H(+)), quasi-neutral, currentless plasma are solved along a closed geomagnetic field line; diffusive equilibrium is not assumed. collisions between all stream pairs and with neutral species are included. The model includes a corotating, tilted dipole magnetic field and neutral winds. Ionospheric sources and sinks are accounted for in a self-consistent manner. Electrons are assumed to be heated by photoelectrons. The model flux tube extends from a 200-km altitude in one hemisphere to a 200-km altitude in the other hemisphere. Initially, the upwelling streams pass through each other practically unimpeded. When the streams approach the boundary in the conjugate ionosphere, a shock develops there, which moves upward and dissipates slowly; at about the same time a reverse shock develops in the hemisphere of origin, which moves upward. After about 1 hour, large shocks develop in each stream near the equator; these shocks move toward the equator and downward after crossing the equator. However, these shocks are probably artificial, because counterstreaming flows occur in each H(+) fluid, which the model can only handle by creating shocks.

  5. The economic value of stream restoration

    NASA Astrophysics Data System (ADS)

    Collins, Alan; Rosenberger, Randy; Fletcher, Jerald

    2005-02-01

    The economic value of restoring Deckers Creek in Monongalia and Preston counties of West Virginia was determined from mail, Internet, and personal contact surveys. Multiattribute, choice experiments were conducted and nested logit models were estimated to derive the economic values of full restoration for three attributes of this creek: aquatic life, swimming, and scenic quality. Their relative economic values were that aquatic life > scenic quality ≈ swimming. These economic values imply that respondents had the highest value for aquatic life when fully restoring Deckers Creek to a sustainable fishery rather than a "put and take" fishery that cannot sustain fish populations. The welfare improvement estimates for full restoration of all three attributes ranged between 12 and 16 per month per household. Potential stream users (anglers) had the largest welfare gain from restoration, while nonangler respondents had the lowest. When these estimates were aggregated up to the entire watershed population, the benefit from restoration of Deckers Creek was estimated to be about $1.9 million annually. This benefit does not account for any economic values from partial stream restoration. On the basis of log likelihood tests of the nested logit models, two subsamples of the survey population (the general population and stream users) were found to be from the same population. Thus restoration choices by stream users may be representative of the watershed population, although the sample size of stream users was small in this research.

  6. Quantitative investigation of acoustic streaming in blood

    NASA Astrophysics Data System (ADS)

    Shi, Xuegong; Martin, Roy W.; Vaezy, Shahram; Crum, Lawrence A.

    2002-02-01

    Acoustic streaming may have practical utility in diagnostic medical ultrasound in distinguishing between stagnant blood and tissue as well as clotted and unclotted blood. This distinction can be difficult with conventional ultrasound but have high value in managing trauma patients with internal hemorrhage. Ultrasound energy applies a force to blood by momentum transfer, resulting in bulk streaming that is a function of the acoustic attenuation, sound speed, acoustic intensity, blood viscosity, and the boundary conditions posed by the geometry around the hematoma. A simple tubular model was studied analytically, by finite element simulation, and experimentally by in vitro measurement. The simulation agreed closely with measurements while the analytic solutions were found to be valid only for beam diameters approximating the diameter of the tubular channel. Experimentally, the acoustic streaming in blood decreased as the blood began to clot and the streaming flow was not detected in clotted blood. In contrast, the echogenicity of the same blood samples did not change appreciably from the unclotted to the clotted state for the stagnant blood studied. Streaming detection appears to offer a potential tool for improving hemorrhage diagnosis.

  7. Evolution of the Quadrantid meteor stream

    NASA Technical Reports Server (NTRS)

    Jones, James; Jones, William

    1992-01-01

    According to previous orbital calculations, the last close approach of the Quadrantid stream with Jupiter occurred 3200 years ago at which time the parent comet of the stream may have been captured into its present short-period orbit. If this is the case the stream may only be a few thousand years old. We have modeled the evolution of the stream to determine if such a short time scale is consistent with the observed features of the Quadrantid/ delta- Aquarid/Arietid/Ursid complex. A detailed modeling of a stream consisting of 500 test particles released 4000 yr ago and which included the effects of the gravitational perturbations of 6 planets as well as the likely spread in the initial orbital elements resulting from the ejection of the grains from the comet was carried out. Our calculations indicate that an intense shower should be seen a few days before the Quadrantid shower, and that, 4000 yr is too short a period for the branch corresponding to the D-Arietid branch to appear. We have considered the quasi-constants of motion 1/a and J, the Tisserand quantity, and find that the Ursids and the D-Arietids are unlikely to be members of the complex, and that, the complex is probably be less than 4000 yr old.

  8. Perturbing Streaming in Dictyostelium discoidium Aggregation

    NASA Astrophysics Data System (ADS)

    Rericha, Erin; Garcia, Gene; Parent, Carole; Losert, Wolfgang

    2009-03-01

    The ability of cells to move towards environmental cues is a critical process allowing the destruction of intruders by the immune system, the formation of the vascular system and the whole scale remodeling of tissues during embryo development. We examine the initial transition from single cell to group migration in the social amoeba Dictyostelium discoidium. Upon starvation, D. discoidium cells enter into a developmental program that triggers solitary cells to aggregate into a multicellular structure. The aggregation is mediated by the small molecule, cyclic-AMP, that cells sense, synthesize, secrete and migrate towards often in a head-to-tail fashion called a stream. Using experiment and numerical simulation, we study the sensitivity of streams to perturbations in the cyclic-AMP concentration field. We find the stability of the streams requires cells to shape the cyclic-AMP field through localized secretion and degradation. In addition, we find the streaming phenotype is sensitive to changes in the substrate properties, with slicker surfaces leading to longer more branched streams that yield large initial aggregates.

  9. Spatial and Temporal Evolution of Stream Bedforms

    NASA Astrophysics Data System (ADS)

    Palmsten, M. L.; Kozarek, J. L.; Calantoni, J.; Kooney, T.; Holland, K.

    2011-12-01

    Streams are complex, dynamic environments that experience significant changes to the bathymetry over the course of hours when sediments are mobilized. Understanding the evolution of stream bed morphology is essential for a broad range of practical purposes including: assessing habitat for fish and forecasting the transport of sediments, nutrients, and pollutants. The objective of this work is to quantify bedform migration at a meander bend in a near-prototype scale laboratory stream and ultimately develop a dataset for comparison with sediment transport models. The spatial and temporal evolution of bedforms was observed at the University of Minnesota's St. Anthony Falls Stream Laboratory. The Outdoor Stream Lab (OSL) is a sandy (D50 = 0.7 mm) , meandering channel approximately 40 m in length 2.7 m in width, and 0.3 m in depth. Observations were made at overbank flow of 284 L/s. Color cameras were positioned at 5 m and 2 m above a meander bend and images were collected at a rate of 7.5 Hz as bedforms migrated through the field of view. Upstream of the meander bend, bedforms were nearly linear and migrated at 0.5 cm/s, while downstream of the bend, bedforms became extremely nonlinear in form and appeared nearly stationary. Images were rectified and post-processed to extract bedform dimensions as well as migration rate. The remotely sensed migration rates were compared with in situ measurements collected using sonar to map bedforms during the experiment.

  10. River restoration and biocoenoses improvement in two streams renaturated using bioengeneering.

    NASA Astrophysics Data System (ADS)

    Leoni, B.; Forasacco, E.; Dobner, R.; Cotta Ramusino, M.

    2003-04-01

    The Bioengineering is a constructive discipline having its own technical, ecological and environmental friendly scopes, by using living materials. The aim of this study is to assess the river restoration efficiency of Bioengineering. The basic goals of many management-concepts are the integrity of the river habitat, self-regulation and self-regeneration, the preservation of intact resources, to recreate the uniqueness, diversity and beauty of natural river landscape. From an ecological point of view the richness, diversity and age composition of the populations developing after restoration as a result of habitat improvement reveal the degree to which comprehensive concepts were applied (Jungwirth et al., 1995). The following results summarised an investigation on streams Boesio and Rancina in Valcuvia, (Varese, Northern Italy). These streams are characterised by human impacts like water pollution, river engineering and river bioengineering (palificata doppia viva). The samples of macrobenthic fauna were collected between August 2000 and July 2001 in 4 stations for each stream, where the 3rd station of Boesio and Rancina streams is characterised by bioengeneering measure, using a Surber sampler (0.125 m2, mesh size 0.45 mm). The zoobenthic communities of these pre-alpine streams are characterised by low richness and diversity and few families and genera were predominant. In Rancina stream, Ephemeroptera (genus Baetis), Trichoptera (families Hydropsychidae, Limnephilidae and Rhyacophilidae) and Diptera (families Chironomidae and Simuliidae) are present throughout the year with significant densities. The faunal composition of Boesio stream is similar. It differs, only, from stream Rancina to costant presence of Plecoptera with genus Leuctra. To evaluate the restoration of environmental quality two indices were applied: Indice Biotico Esteso (I.B.E.- Ghetti, 1995); Indice di Funzionalit Fluviale (I.F.F.- Siligardi, 2000). The E.B.I. scores of Boesio stream indicate that stations 1 and 2 are in good condition (Ecological status classification: II): therefore the level of diversity and abundance of macrobenthic taxa is slightly outside the range associated with the normal conditions and the most of the sensitive taxa of the type specific communities are present. The stations 3 and 4 are in moderate condition (Ecological status classification: III): the level of diversity and abundance of invertebrate taxa is moderately outside the normal condition range, the taxa indicative of pollution are present and many of the sensitive taxa of the type specific communities are absent. In the Rancina stream in all of the 4 stations the ecological status is indicated like moderate (Ecological status classification: III): there is a predominance of taxa more resistant at pollution and at changes in other biological components of the stream. The I.F.F. show that in Boesio stream the right shore score is moderate-good and the left shore score is moderate-poor. Differently, the Rancina stream presents the right shore with a value poor and the left shore with a wide gradient between good and poor-bad. In conclusion, we can affirm the low efficiency of Bioengineering to restore the Boesio and Rancina streams, because we cannot observe the habitat and aquatic biocoenoses improvement. An explication could be that the conversions are restricted to morphological measures, which are carried out on a small way of banks. Whereas, the restoration using the Bioengineering requires taking the entire catchment area into consideration.

  11. Segregation and integration of auditory streams when listening to multi-part music.

    PubMed

    Ragert, Marie; Fairhurst, Merle T; Keller, Peter E

    2014-01-01

    In our daily lives, auditory stream segregation allows us to differentiate concurrent sound sources and to make sense of the scene we are experiencing. However, a combination of segregation and the concurrent integration of auditory streams is necessary in order to analyze the relationship between streams and thus perceive a coherent auditory scene. The present functional magnetic resonance imaging study investigates the relative role and neural underpinnings of these listening strategies in multi-part musical stimuli. We compare a real human performance of a piano duet and a synthetic stimulus of the same duet in a prioritized integrative attention paradigm that required the simultaneous segregation and integration of auditory streams. In so doing, we manipulate the degree to which the attended part of the duet led either structurally (attend melody vs. attend accompaniment) or temporally (asynchronies vs. no asynchronies between parts), and thus the relative contributions of integration and segregation used to make an assessment of the leader-follower relationship. We show that perceptually the relationship between parts is biased towards the conventional structural hierarchy in western music in which the melody generally dominates (leads) the accompaniment. Moreover, the assessment varies as a function of both cognitive load, as shown through difficulty ratings and the interaction of the temporal and the structural relationship factors. Neurally, we see that the temporal relationship between parts, as one important cue for stream segregation, revealed distinct neural activity in the planum temporale. By contrast, integration used when listening to both the temporally separated performance stimulus and the temporally fused synthetic stimulus resulted in activation of the intraparietal sulcus. These results support the hypothesis that the planum temporale and IPS are key structures underlying the mechanisms of segregation and integration of auditory streams, respectively. PMID:24475030

  12. Can rehabilitation techniques in agricultural streams influence transient storage and nitrate uptake?

    NASA Astrophysics Data System (ADS)

    Mueller Price, J.; Baker, D. W.; Bledsoe, B.

    2009-12-01

    Headwater streams are a crucial component of nutrient processing in watersheds, partly due to high surface-to-volume ratios that favor nitrate uptake and to the large percentage of headwater stream length in the total length of a river system. We explore the potential of two stream rehabilitation approaches in headwater streams to promote nitrate uptake and reduce down-stream nitrogen pollution. We investigated two streams, Sheep Creek and Nunn Creek, located in northern Colorado that have been influenced by live-stock grazing. Sections of Sheep Creek were fenced off and exclosed from open rangeland cattle grazing in the 1950s, allowing riparian corridors of these sections to naturally revegetate, while other sections have been continu-ally grazed. In 2003, restoration structures of rootwads and j-hook vanes were constructed along portions of Nunn Creek for bank stabilization and trout habitat enhancement. We studied four reaches along Sheep Creek, two reaches exclosed from grazing and two reaches currently grazed. We also studied two reaches along Nunn Creek, one with restoration structures and one without structures. We performed nutrient injections of bromide and nitrate to estimate transient storage and nitrate uptake in each reach. Comprehensive data sets were also collected to characterize physical complexity along each reach, including pebble counts, longitudinal profiles, cross-section surveys, hydraulic measurements, benthic organic matter (fine and coarse), and spatial distribution of physical habitat units. We developed regression models that relate parameters of geomorphic complexity with transient storage and nitrate uptake parameters to describe how the geomorphic complexity associated with rehabilitation techniques in each reach can influence transient storage and nitrate uptake.

  13. Digital Multicasting of Multiple Audio Streams

    NASA Technical Reports Server (NTRS)

    Macha, Mitchell; Bullock, John

    2007-01-01

    The Mission Control Center Voice Over Internet Protocol (MCC VOIP) system (see figure) comprises hardware and software that effect simultaneous, nearly real-time transmission of as many as 14 different audio streams to authorized listeners via the MCC intranet and/or the Internet. The original version of the MCC VOIP system was conceived to enable flight-support personnel located in offices outside a spacecraft mission control center to monitor audio loops within the mission control center. Different versions of the MCC VOIP system could be used for a variety of public and commercial purposes - for example, to enable members of the general public to monitor one or more NASA audio streams through their home computers, to enable air-traffic supervisors to monitor communication between airline pilots and air-traffic controllers in training, and to monitor conferences among brokers in a stock exchange. At the transmitting end, the audio-distribution process begins with feeding the audio signals to analog-to-digital converters. The resulting digital streams are sent through the MCC intranet, using a user datagram protocol (UDP), to a server that converts them to encrypted data packets. The encrypted data packets are then routed to the personal computers of authorized users by use of multicasting techniques. The total data-processing load on the portion of the system upstream of and including the encryption server is the total load imposed by all of the audio streams being encoded, regardless of the number of the listeners or the number of streams being monitored concurrently by the listeners. The personal computer of a user authorized to listen is equipped with special- purpose MCC audio-player software. When the user launches the program, the user is prompted to provide identification and a password. In one of two access- control provisions, the program is hard-coded to validate the user s identity and password against a list maintained on a domain-controller computer at the MCC. In the other access-control provision, the program verifies that the user is authorized to have access to the audio streams. Once both access-control checks are completed, the audio software presents a graphical display that includes audiostream-selection buttons and volume-control sliders. The user can select all or any subset of the available audio streams and can adjust the volume of each stream independently of that of the other streams. The audio-player program spawns a "read" process for the selected stream(s). The spawned process sends, to the router(s), a "multicast-join" request for the selected streams. The router(s) responds to the request by sending the encrypted multicast packets to the spawned process. The spawned process receives the encrypted multicast packets and sends a decryption packet to audio-driver software. As the volume or muting features are changed by the user, interrupts are sent to the spawned process to change the corresponding attributes sent to the audio-driver software. The total latency of this system - that is, the total time from the origination of the audio signals to generation of sound at a listener s computer - lies between four and six seconds.

  14. On the genealogy of the Orphan Stream

    NASA Astrophysics Data System (ADS)

    Sales, Laura V.; Helmi, Amina; Starkenburg, Else; Morrison, Heather L.; Engle, Ethan; Harding, Paul; Mateo, Mario; Olszewski, Edward W.; Sivarani, Thirupathi

    2008-09-01

    We use N-body simulations to explore the origin and a plausible orbit for the Orphan Stream, one of the faintest substructures discovered so far in the outer halo of our Galaxy. We are able to reproduce its position, velocity and distance measurements by appealing to a single wrap of a double-component satellite galaxy. We find that the progenitor of the Orphan Stream could have been an object similar to today's Milky Way dwarfs, such as Carina, Draco, LeoII or Sculptor; and unlikely to be connected to Complex A or Ursa MajorII. Our models suggest that such progenitors, if accreted on orbits with apocentres smaller than ~35 kpc, are likely to give rise to very low surface brightness streams, which may be hiding in the outer halo and remain largely undetected with current techniques. The systematic discovery of these ghostly substructures may well require wide field spectroscopic surveys of the Milky Way's outer stellar halo.

  15. VOTable JAVA Streaming Writer and Applications.

    NASA Astrophysics Data System (ADS)

    Kulkarni, P.; Kembhavi, A.; Kale, S.

    2004-07-01

    Virtual Observatory related tools use a new standard for data transfer called the VOTable format. This is a variant of the xml format that enables easy transfer of data over the web. We describe a streaming interface that can bridge the VOTable format, through a user friendly graphical interface, with the FITS and ASCII formats, which are commonly used by astronomers. A streaming interface is important for efficient use of memory because of the large size of catalogues. The tools are developed in JAVA to provide a platform independent interface. We have also developed a stand-alone version that can be used to convert data stored in ASCII or FITS format on a local machine. The Streaming writer is successfully being used in VOPlot (See Kale et al 2004 for a description of VOPlot).We present the test results of converting huge FITS and ASCII data into the VOTable format on machines that have only limited memory.

  16. Waste streams in a crewed space habitat

    NASA Technical Reports Server (NTRS)

    Wydeven, T.; Golub, M. A.

    1991-01-01

    A judicious compilation of generation rates and chemical compositions of potential waste feed streams in a typical crewed space habitat was made in connection with the waste-management aspect of NASA's Physical/Chemical Closed-Loop Life Support Program. Waste composition definitions are needed for the design of waste-processing technologies involved in closing major life support functions in future long-duration human space missions. Tables of data for the constituents and chemical formulas of the following waste streams are presented and discussed: human urine, feces, hygiene (laundry and shower) water, cleansing agents, trash, humidity condensate, dried sweat, and trace contaminants. Tables of data on dust generation and pH values of the different waste streams are also presented and discussed.

  17. Programmable stream prefetch with resource optimization

    SciTech Connect

    Boyle, Peter; Christ, Norman; Gara, Alan; Mawhinney, Robert; Ohmacht, Martin; Sugavanam, Krishnan

    2013-01-08

    A stream prefetch engine performs data retrieval in a parallel computing system. The engine receives a load request from at least one processor. The engine evaluates whether a first memory address requested in the load request is present and valid in a table. The engine checks whether there exists valid data corresponding to the first memory address in an array if the first memory address is present and valid in the table. The engine increments a prefetching depth of a first stream that the first memory address belongs to and fetching a cache line associated with the first memory address from the at least one cache memory device if there is not yet valid data corresponding to the first memory address in the array. The engine determines whether prefetching of additional data is needed for the first stream within its prefetching depth. The engine prefetches the additional data if the prefetching is needed.

  18. Don't Cross the (Tidal) Streams

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    In a tidal disruption event (TDE), an unfortunate star passes too close to a dormant supermassive black hole (BH) and gets torn apart by tidal forces, feeding the BH for a short time. Oddly, were not finding nearly as many TDEs typically detected due to their distinctive observational signatures as theory says we should. A recent study suggests that we might be missing many of these events, due to the way the streams of shredded stars fall onto the BHs.Signatures of ShreddingWhen a BH tears a star apart, the stars material is stretched out into whats known as a tidal stream. That stream continues on a trajectory around the BH, with roughly half the material eventually falling back on the BH, whipping around it in a series of orbits. Where those orbits intersect each other, the material smashes together and circularizes, forming a disk that then accretes onto the BH.What does a TDE look like? We dont observe anything until after the tidal streams collide and the material begins to accrete onto the BH. At that point we observe a sudden peak in luminosity, which then gradually decreases (scaling roughly as time-5/3) as the tail end of whats left of the star accretes and the BHs food source eventually runs out.So why have we only been observing about a tenth as many TDEs as theory predicts we should see? By studying the structure of tidal streams in TDEs, James Guillochon (Harvard-Smithsonian Center for Astrophysics) and Enrico Ramirez-Ruiz (UC Santa Cruz) have found a potential reason and the culprit is general relativity.Dark YearsThe authors run a series of simulations of TDEs around black holes of varying masses and spins to see what form the resulting tidal streams take over time. They find that precession of the tidal stream due to the BHs gravitational effects changes how the stream interacts with itself, and therefore what we observe. Some cases behave like what we expect for whats currently considered a typical TDE but some dont.Example from simulations of a tidal streams path around the black hole. Relativistic precession causes this tidal stream to wind around the black hole 13 times before it finally collides with itself. [GuillochonRamirez-Ruiz 2015]For cases where the relativistic effects are small (such as BHs with masses less than a few 106 solar masses), the tidal stream collides with itself after only a few windings around the BH, quickly forming a disk. The disk forms far from the BH, however, so it takes a long time to accrete. As a result, the observed flare can take 100 times longer to peak than whats typically expected for a TDE, so we might be failing to identify these sources as TDEs.Furthermore, for cases where the BH is both massive and has a spin of a 0.2, the tidal stream doesnt collide with itself right away. Instead, it can take many windings around the BH before the first intersection. In these cases, it may potentially be years after a star gets ripped apart before the material accretes and were able to observe the event!CitationJames Guillochon and Enrico Ramirez-Ruiz 2015 ApJ 809 166. doi:10.1088/0004-637X/809/2/166

  19. Whipple's ejection model and the Geminid stream

    NASA Astrophysics Data System (ADS)

    Jones, J.; Poole, L. M. G.; Webster, A. R.

    2016-02-01

    Many attempts to model the Geminid meteor stream have been based on Whipple's model for the ejection of meteoroids from comets. Using the most accurate data available from the IAU photographic meteor data base and by considering the scatter of the secularly near-invariant quantities of the simulated ejected test particles predicted by applying Whipple's model to the asteroid Phaethon - the prime candidate for the progenitor of the Geminid stream - we show that the model predicts ejection speeds that are about a factor of at least 3 too low. We have considered the other candidate progenitors: the asteroids 2005 UD and 1999 YC, and find neither of these to be credible candidates although we find that 2005 is the likely parent of the day-time Sextantid stream.

  20. Cytoplasmic Streaming - Skylab Student Experiment ED-63

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This chart describes the Skylab student experiment (ED-63), Cytoplasmic Streaming, proposed by Cheryl A. Peitz of Arapahoe High School, Littleton, Colorado. Experiment ED-63 was to observe the effect of zero-gravity on cytoplasmic streaming in the aquatic plant named Elodea, commonly called water weed or water thyme. The phenomenon of cytoplasmic streaming is not well understood, but it is recognized as the circulation mechanism of the internal materials or cytoplasm of a cell. Cytoplasm is a gelatinous substance that has the ability to change its viscosity and flow, carrying various cell materials with it. The activity can be stimulated by sunlight or heat. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

  1. Effect of upstream ponds on stream temperature

    NASA Astrophysics Data System (ADS)

    Ham, J.; Toran, L.; Cruz, J.

    2006-05-01

    Many tributaries feeding streams are connected to ponds that heat up during summer months; however, the influence of these ponds on receiving stream temperature was not known. Stream temperature affects microfauna and fish habitats in aquatic ecosystems. Three tributaries with headwater ponds exposed to sunlight and one tributary unassociated with a large, upstream pond were selected for study within the Pennypack Creek watershed in the Philadelphia Metropolitan Area. Temperature loggers were installed in the pond (when applicable), associated tributary, and in the Pennypack Creek up and downstream of its confluence with the tributary. Although diurnal temperature fluctuations were apparent, the study showed no significant differences in temperature up and downstream of tributary discharge to Pennypack Creek. Pond water temperatures were up to 4C warmer than the Pennypack Creek; however, temperatures downstream and upstream of the tributaries leading out of the ponds were within 1C of each other.

  2. Observations of ion streaming during substorms

    NASA Technical Reports Server (NTRS)

    Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.

    1983-01-01

    The ion beam phenomenon at the plasma sheet boundary is examined for individually identifiable substorms, and the substorm-associated particle phenomena are evaluated in terms of the energy-angle distributions of the plasma population and three-dimensional energetic ion distributions. In all seven cases studied it is found that ion beams streaming earthward and/or tailward are always present at the edge of the plasma sheet adjacent to the tail lobe. Ion beams penetrating into the plasma sheet region with no detectable density gradient are also observed. Beams at tens to hundreds of eV often stream tailward and are often long lasting, suggesting that they may be related to ionospheric sources. Both tailward and earthward streaming beams are detected for ion beams above 1 keV, consistent with an origin from the distant tail, propagation toward earth, and mirroring back under single particle motions.

  3. Conversion method for gas streams containing hydrocarbons

    DOEpatents

    Mallinson, Richard G.; Lobban, Lance; Liu, Chang-jun

    2000-01-01

    An apparatus and a method of using the apparatus are provided for converting a gas stream containing hydrocarbons to a reaction product containing effluent molecules having at least one carbon atom, having at least one interior surface and at least one exterior surface, a first electrode and a second electrode with the first and second electrodes being selectively movable in relation to each other and positioned within the housing so as to be spatially disposed a predetermined distance from each other, a plasma discharge generator between the first and second electrodes, gas stream introducer and a collector for collecting the reaction product effluent produced by the reaction of the gas stream containing hydrocarbons with the plasma discharge between the first and second electrodes.

  4. Don't Cross the (Tidal) Streams

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    In a tidal disruption event (TDE), an unfortunate star passes too close to a dormant supermassive black hole (BH) and gets torn apart by tidal forces, feeding the BH for a short time. Oddly, were not finding nearly as many TDEs typically detected due to their distinctive observational signatures as theory says we should. A recent study suggests that we might be missing many of these events, due to the way the streams of shredded stars fall onto the BHs.Signatures of ShreddingWhen a BH tears a star apart, the stars material is stretched out into whats known as a tidal stream. That stream continues on a trajectory around the BH, with roughly half the material eventually falling back on the BH, whipping around it in a series of orbits. Where those orbits intersect each other, the material smashes together and circularizes, forming a disk that then accretes onto the BH.What does a TDE look like? We dont observe anything until after the tidal streams collide and the material begins to accrete onto the BH. At that point we observe a sudden peak in luminosity, which then gradually decreases (scaling roughly as time-5/3) as the tail end of whats left of the star accretes and the BHs food source eventually runs out.So why have we only been observing about a tenth as many TDEs as theory predicts we should see? By studying the structure of tidal streams in TDEs, James Guillochon (Harvard-Smithsonian Center for Astrophysics) and Enrico Ramirez-Ruiz (UC Santa Cruz) have found a potential reason and the culprit is general relativity.Dark YearsThe authors run a series of simulations of TDEs around black holes of varying masses and spins to see what form the resulting tidal streams take over time. They find that precession of the tidal stream due to the BHs gravitational effects changes how the stream interacts with itself, and therefore what we observe. Some cases behave like what we expect for whats currently considered a typical TDE but some dont.Example from simulations of a tidal streams path around the black hole. Relativistic precession causes this tidal stream to wind around the black hole 13 times before it finally collides with itself. [GuillochonRamirez-Ruiz 2015]For cases where the relativistic effects are small (such as BHs with masses less than a few 106 solar masses), the tidal stream collides with itself after only a few windings around the BH, quickly forming a disk. The disk forms far from the BH, however, so it takes a long time to accrete. As a result, the observed flare can take 100 times longer to peak than whats typically expected for a TDE, so we might be failing to identify these sources as TDEs.Furthermore, for cases where the BH is both massive and has a spin of a 0.2, the tidal stream doesnt collide with itself right away. Instead, it can take many windings around the BH before the first intersection. In these cases, it may potentially be years after a star gets ripped apart before the material accretes and were able to observe the event!CitationJames Guillochon and Enrico Ramirez-Ruiz 2015 ApJ 809 166. doi:10.1088/0004-637X/809/2/166

  5. Variation in root density along stream banks.

    PubMed

    Wynn, Theresa M; Mostaghimi, Saied; Burger, James A; Harpold, Adrian A; Henderson, Marc B; Henry, Leigh-Anne

    2004-01-01

    While it is recognized that vegetation plays a significant role in stream bank stabilization, the effects are not fully quantified. The study goal was to determine the type and density of vegetation that provides the greatest protection against stream bank erosion by determining the density of roots in stream banks. To quantify the density of roots along alluvial stream banks, 25 field sites in the Appalachian Mountains were sampled. The riparian buffers varied from short turfgrass to mature riparian forests, representing a range of vegetation types. Root length density (RLD) with depth and aboveground vegetation density were measured. The sites were divided into forested and herbaceous groups and differences in root density were evaluated. At the herbaceous sites, very fine roots (diameter < 0.5 mm) were most common and more than 75% of all roots were concentrated in the upper 30 cm of the stream bank. Under forested vegetation, fine roots (0.5 mm < diameter < 2.0 mm) were more common throughout the bank profile, with 55% of all roots in the top 30 cm. In the top 30 cm of the bank, herbaceous sites had significantly greater overall RLD than forested sites (alpha = 0.01). While there were no significant differences in total RLD below 30 cm, forested sites had significantly greater concentrations of fine roots, as compared with herbaceous sites (alpha = 0.01). As research has shown that erosion resistance has a direct relationship with fine root density, forested vegetation may provide better protection against stream bank erosion. PMID:15537925

  6. Stellar Tidal Streams in External Galaxies

    NASA Astrophysics Data System (ADS)

    Carlin, Jeffrey L.; Beaton, Rachael L.; Martínez-Delgado, David; Gabany, R. Jay

    In order to place the highly substructured stellar halos of the Milky Way and M31 in a larger context of hierarchical galaxy formation, it is necessary to understand the prevalence and properties of tidal substructure around external galaxies. This chapter details the current state of our observational knowledge of streams in galaxies in and beyond the Local Group, which are studied both in resolved stellar populations and in integrated light. Modeling of individual streams in extragalactic systems is hampered by our inability to obtain resolved stellar kinematics in the streams, though many streams contain alternate luminous kinematic tracers, such as globular clusters or planetary nebulae. We compare the observed structures to the predictions of models of galactic halo formation, which provide insight into the number and properties of streams expected around Milky Way like galaxies. More specifically, we discuss the inferences that can be made about stream progenitors based only on observed morphologies. We expand our discussion to consider hierarchical accretion at lower mass scales, in particular the observational evidence that substructure exists on smaller mass scales and the effects accretion events may have on the evolution of dwarf galaxies (satellite or isolated). Lastly, we discuss potential correlations between the presence of substructure in the halo and the structural properties of the disk. While many exciting discoveries have been made of tidal substructures around external galaxies, the "global" questions of galaxy formation and evolution via hierarchical accretion await a more complete census of the low surface brightness outskirts of galaxies in and beyond the Local Group.

  7. Identifying hidden voice and video streams

    NASA Astrophysics Data System (ADS)

    Fan, Jieyan; Wu, Dapeng; Nucci, Antonio; Keralapura, Ram; Gao, Lixin

    2009-04-01

    Given the rising popularity of voice and video services over the Internet, accurately identifying voice and video traffic that traverse their networks has become a critical task for Internet service providers (ISPs). As the number of proprietary applications that deliver voice and video services to end users increases over time, the search for the one methodology that can accurately detect such services while being application independent still remains open. This problem becomes even more complicated when voice and video service providers like Skype, Microsoft, and Google bundle their voice and video services with other services like file transfer and chat. For example, a bundled Skype session can contain both voice stream and file transfer stream in the same layer-3/layer-4 flow. In this context, traditional techniques to identify voice and video streams do not work. In this paper, we propose a novel self-learning classifier, called VVS-I , that detects the presence of voice and video streams in flows with minimum manual intervention. Our classifier works in two phases: training phase and detection phase. In the training phase, VVS-I first extracts the relevant features, and subsequently constructs a fingerprint of a flow using the power spectral density (PSD) analysis. In the detection phase, it compares the fingerprint of a flow to the existing fingerprints learned during the training phase, and subsequently classifies the flow. Our classifier is not only capable of detecting voice and video streams that are hidden in different flows, but is also capable of detecting different applications (like Skype, MSN, etc.) that generate these voice/video streams. We show that our classifier can achieve close to 100% detection rate while keeping the false positive rate to less that 1%.

  8. Creating living machines

    PubMed Central

    Kamm, Roger D.; Bashir, Rashid

    2015-01-01

    Development of increasingly complex integrated cellular systems will be a major challenge for the next decade and beyond, as we apply the knowledge gained from the sub-disciplines of tissue engineering, synthetic biology, micro-fabrication and nanotechnology, systems biology, and developmental biology. In this prospective, we describe the current state-of-the-art in the context of differentiating source cells from more primitive, pluripotent cells, and organizing these cells into populations of a single cell type to produce the components or building blocks of higher order systems and finally, combining multiple cell types, possibly in combination with scaffolds possessing specific physical or chemical properties, to produce greater functionality. As these living machines increase in capabilities, exhibit emergent behavior and potentially reveal the ability for self-assembly, self-repair, and even self-replication, questions arise regarding the ethical implications of this work. Future prospects as well as ways of addressing these complex ethical questions will be addressed. PMID:24006130

  9. Fair society, healthy lives.

    PubMed

    Marmot, M; Bell, R

    2012-09-01

    The final report of the World Health Organization Commission on the Social Determinants of Health (CSDH), published in 2008, affirmed that social injustice was killing on a grand scale, with a toxic combination of 'poor social policies and programmes, unfair economic arrangements, and bad politics' being responsible for producing and reinforcing health inequalities. It provided a comprehensive evidence-based discussion of pervasive inequalities of health in many countries, demonstrating the presence of a social gradient in health outcomes associated with the unfair distribution of the social determinants of health. The social determinants of health include the conditions in which people are born, grow, live, work and age, and the fundamental drivers of these conditions: the distribution of power; money; and resources. Following publication of the CSDH report and recommendations for action, the UK Government commissioned a Strategic Review of Health Inequalities in England. This article provides an overview and reflection on the findings from the CSDH and the Strategic Review of Health Inequalities in England, reviewing the case for putting fairness at the heart of all policy making. In the process, it highlights the need for action on the social determinants of health in order to address health inequalities and the social gradient in health outcomes. PMID:22784581

  10. Live imaging of GFP-labeled proteins in Drosophila oocytes.

    PubMed

    Pokrywka, Nancy Jo

    2013-01-01

    The Drosophila oocyte has been established as a versatile system for investigating fundamental questions such as cytoskeletal function, cell organization, and organelle structure and function. The availability of various GFP-tagged proteins means that many cellular processes can be monitored in living cells over the course of minutes or hours, and using this technique, processes such as RNP transport, epithelial morphogenesis, and tissue remodeling have been described in great detail in Drosophila oocytes. The ability to perform video imaging combined with a rich repertoire of mutants allows an enormous variety of genes and processes to be examined in incredible detail. One such example is the process of ooplasmic streaming, which initiates at mid-oogenesis. This vigorous movement of cytoplasmic vesicles is microtubule and kinesin-dependent and provides a useful system for investigating cytoskeleton function at these stages. Here I present a protocol for time lapse imaging of living oocytes using virtually any confocal microscopy setup. PMID:23567977

  11. Updates to the MSFC Meteoroid Stream Model

    NASA Astrophysics Data System (ADS)

    Moser, Danielle E.; Cooke, William J.

    2008-06-01

    The Marshall Space Flight Center (MSFC) Meteoroid Stream Model simulates particle ejection and subsequent evolution from comets in order to provide meteor shower forecasts to spacecraft operators for hazard mitigation and planning purposes. The model, previously detailed in Moser and Cooke (Earth Moon Planets 95, 141 (2004)), has recently been updated; the changes include the implementation of the RADAU integrator, an improved planetary treatment, and the inclusion of general relativistic effects in the force function. The results of these updates are investigated with respect to various meteoroid streams and the outcome presented.

  12. Beaded streams of Arctic permafrost landscapes

    NASA Astrophysics Data System (ADS)

    Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. C.

    2014-07-01

    Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic inventory of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high-ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate relatively stable form and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in stream gulches effectively insulates river ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools stratify thermally, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m s-1, yet channel runs still move water rapidly between pools. This repeating spatial pattern associated with beaded stream morphology and hydrological dynamics may provide abundant and optimal foraging habitat for fish. Thus, beaded streams may create important ecosystem functions and habitat in many permafrost landscapes and their distribution and dynamics are only beginning to be recognized in Arctic research.

  13. Sulfur dioxide removal from gas streams

    SciTech Connect

    Urban, P.; Ginger, E.A.

    1986-11-11

    A process is described for removal of sulfur dioxide pollutant gas from gas stream which comprises contacting the gas stream with pretreated shale in the form of an aqueous solution of aluminum sulfate including from about 0.1 to about 2.0% by weight of the pretreated shale. The pretreatment of the shale comprises the heating of the shale in the presence of a gas unable to support combustion at a temperature in a range of from about 340/sup 0/C. to about 480/sup 0/C.

  14. Are cosmological neutrinos free-streaming?

    SciTech Connect

    Basboell, Anders; Bjaelde, Ole Eggers; Hannestad, Steen; Raffelt, Georg G.

    2009-02-15

    Precision data from cosmology suggest neutrinos stream freely and hence interact very weakly around the epoch of recombination. We study this issue in a simple framework where neutrinos recouple instantaneously and stop streaming freely at a redshift z{sub i}. The latest cosmological data imply z{sub i} < or approx. 1500, the exact constraint depending somewhat on the assumed prior on z{sub i}. This bound can be translated into a bound on the coupling strength between neutrinos and majoronlike particles.

  15. Investigating methods of stream planform identification

    NASA Astrophysics Data System (ADS)

    Lohberg, M. M.; Lusk, K.; Miller, D.; Stonedahl, F.; Stonedahl, S. H.

    2013-12-01

    Stream planforms are used to map scientific measurements, estimate volumetric discharge, and model stream flow. Changes in these planforms can be used to quantify erosion and water level fluctuations. This research investigated five cost-effective methods of identifying stream planforms: (1) consumer-grade digital camera GPS (2) multi-view stereo 3D scene reconstruction (using Microsoft Photosynth (TM)) (3) a cross-sectional measurement approach (4) a triangulation-based measurement approach and (5) the 'square method' - a novel photogrammetric procedure which involved floating a large wooden square in the stream, photographing the square and banks from numerous angles and then using the square to correct for perspective and extract the outline (using custom post-processing software). Data for each of the five methods was collected at Blackhawk Creek in Davenport, Iowa. Additionally we placed 30 control points near the banks of the stream and measured 88 lengths between these control points. We measured or calculated the locations of these control points with each of our five methods and calculated the average percent error associated with each method using the predicted control point locations. The effectiveness of each method was evaluated in terms of accuracy, affordability, environmental intrusiveness, and ease of use. The camera equipped with GPS proved to be a very ineffective method due to an extremely high level of error, 289%. The 3D point cloud extracted from Photosynth was missing markers for many of the control points, so the error calculation (which yielded 11.7%) could only be based on five of the 88 lengths and is thus highly uncertain. The two non-camera methods (cross-sectional and triangulation measurements) resulted in low percent error (2.04% and 1.31% respectively) relative to the control point lengths, but these methods were very time consuming, exhausting, and only provided low resolution outlines. High resolution data collection would require even smaller increments, drastically increasing field work time. These two non-photo methods also disturb the sediments in the stream, which may be undesirable. Finally, the 'square method' provided a high resolution outline with only a 1.51% error and was relatively easy to complete in the field. It did, however, require a great-deal of manual post-processing time. Despite this caveat, we recommend the square method as an inexpensive procedure for obtaining fine resolution planform data with minimal disturbance to the stream environment. Stream planforms and calculated control point locations with respective average percent errors

  16. Living with Thrombotic Thrombocytopenic Purpura

    MedlinePLUS

    ... from the NHLBI on Twitter. Living With Thrombotic Thrombocytopenic Purpura Some people fully recover from thrombotic thrombocytopenic purpura (TTP). However, relapses (flareups) can occur in many ...

  17. Lives Worth Living: Religious Education and Social Movements

    ERIC Educational Resources Information Center

    Ayres, Jennifer R.

    2013-01-01

    When people of faith participate in movements for social change, how are their religious and moral identities formed, challenged, and transformed? Although they have explicit and tangible goals as they participate in advocacy, protest, and boycotts, religious social activists also, James Jasper argues, craft "lives worth living" (1997).

  18. Estimating stream filtration from a meandering stream under the Robin condition

    NASA Astrophysics Data System (ADS)

    Huang, Ching-Sheng; Yeh, Hund-Der

    2015-06-01

    This study applies image well theory to estimate the stream depletion rate (SDR) due to pumping near a meandering stream with a clogged streambed treated as the Robin condition. The stream is considered as an irregular boundary represented by discrete nodes. Image wells are arranged along the stream and near those nodes. On the basis of the Theis (1935) solution and the principle of superposition, the solution for the aquifer drawdown subject to the stream can then be expressed as the sum of the Theis solution and a simple series representing the effect of those image wells. The discharge rates of the image wells are determined by solving a system of equations obtained by substituting the drawdown solution into the Robin condition. Quantitative criteria for assessing the applicability of the image well theory are provided. On the basis of the drawdown solution and Darcy's law, the analytical solution for SDR can then be obtained. A finite element solution is also developed to verify the SDR solution. Temporal SDR distributions predicted by both the analytical solution and finite element solution agree well over the entire period except at late time when the stream filtration rate approaches the pumping rate (i.e., SDR ≅ 1). It is found that a meandering stream has a significant effect on SDR compared with a rectilinear one and the effect should be taken into account in estimating SDR.

  19. Twenty-eight Years of Stream Invertebrate Abundance, Biomass, and Secondary Production From Three Headwater Streams

    NASA Astrophysics Data System (ADS)

    Wallace, J.; Eggert, S. L.; Cross, W. F.; Rosemond, A. D.; Meyer, J. L.

    2005-05-01

    We analyzed 28 years of abundance, biomass and secondary production data from 3 headwater streams at the Coweeta Hydrologic Laboratory, NC, USA. These data include years of extreme drought and precipitation (78-y record) and 8 years of reduced litter inputs (litter exclusion) and wood removal for one stream. Analysis of functional feeding group (FFG) proportions revealed strong habitat-specific preferences for either mixed substrates or bedrock outcrop habitats, with remarkable between year similarities. For both reference streams and litter reduction streams there was a significant relationship between annual CPOM standing crop and secondary production for the dominant mixed substrate habitats. Habitat-weighted production across reference streams averaged 8.2 g AFDM/m2/y (range = 4.6 to 13.2) versus 1.7 g AFDM/m2/y (range = 0.9 to 3.5) for litter exclusion years. Predator production was strongly correlated (P<0.001) with total secondary production over all years, and based on known bioenergetic efficiencies, indicate the importance of predators in these streams. Our study suggests that trophic interactions, including standing crop of CPOM as a food source, strongly influence secondary production in these headwater streams.

  20. Hydrologic Retention in Supraglacial Streams: Results from an in-stream injection experiment

    NASA Astrophysics Data System (ADS)

    Nassry, M. Q.; Scott, D.; Hood, E. W.

    2009-12-01

    Rising air temperatures and extended daylight hours result in increased surface melting from glaciers during the summer months. As water moves across the glacier and concentrates over cracks in the ice, supraglacial streams are formed. These supraglacial streams are important conduits for the down glacier movement of meltwater from snow and glacier ice. The objective of this research was to quantify advection, dispersion, and storage zone interactions within a supraglacial stream, which in turn will be used to assess biogeochemical reactivity within these environments. We co-injected a conservative salt in conjunction with reactive nutrients (e.g. labile DOM, NH4+, and PO4-) over a 4-hour period into a supraglacial stream on the Mendenhall Glacier located in the Juneau Icefield in southeastern Alaska. Samples were collected from an upstream background site, three locations in the main channel, and during a synoptic sampling effort along the entire study reach, which included a wide, shallow pool. Preliminary analyses suggest that transient storage exchange alters hydrologic retention within these stream environments, but only within reaches characterized by shallow diffuse flow in contrast to fast, deeper sections of these supraglacial channels. Transient storage within these channels is limited to surface pools, since the bottom of the channel is ice. Our next steps will use the hydrologic results to quantify in-stream reactivity and nutrient retention from the non-conservative tracers. Our findings here will enhance the understanding of solute fate and transport within supraglacial streams in landscapes undergoing rapid glacial recession.

  1. Quality control in the recycling stream of PVC from window frames by hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Luciani, Valentina; Serranti, Silvia; Bonifazi, Giuseppe; Di Maio, Francesco; Rem, Peter

    2013-05-01

    Polyvinyl chloride (PVC) is one of the most commonly used thermoplastic materials in respect to the worldwide polymer consumption. PVC is mainly used in the building and construction sector, products such as pipes, window frames, cable insulation, floors, coverings, roofing sheets, etc. are realised utilising this material. In recent years, the problem of PVC waste disposal gained increasing importance in the public discussion. The quantity of used PVC items entering the waste stream is gradually increased as progressively greater numbers of PVC products approach to the end of their useful economic lives. The quality of the recycled PVC depends on the characteristics of the recycling process and the quality of the input waste. Not all PVC-containing waste streams have the same economic value. A transparent relation between value and composition is required to decide if the recycling process is cost effective for a particular waste stream. An objective and reliable quality control technique is needed in the recycling industry for the monitoring of both recycled flow streams and final products in the plant. In this work hyperspectral imaging technique in the near infrared (NIR) range (1000-1700 nm) was applied to identify unwanted plastic contaminants and rubber present in PVC coming from windows frame waste in order to assess a quality control procedure during its recycling process. Results showed as PVC, PE and rubber can be identified adopting the NIR-HSI approach.

  2. In-stream sorption of fulvic acid in an acidic stream: A stream-scale transport experiment

    USGS Publications Warehouse

    McKnight, Diane M.; Hornberger, G.M.; Bencala, K.E.; Boyer, E.W.

    2002-01-01

    The variation of concentration and composition of dissolved organic carbon (DOC) in stream waters cannot be explained solely on the basis of soil processes in contributing subcatchments. To investigate in-stream processes that control DOC, we injected DOC-enriched water into a reach of the Snake River (Summit County, Colorado) that has abundant iron oxyhydroxides coating the streambed. The injected water was obtained from the Suwannee River (Georgia), which is highly enriched in fulvic acid. The fulvic acid from this water is the standard reference for aquatic fulvic acid for the International Humic Substances Society and has been well characterized. During the experimental injection, significant removal of sorbable fulvic acid occurred within the first 141 m of stream reach. We coinjected a conservative tracer (lithium chloride) and analyzed the results with the one-dimensional transport with inflow and storage (OTIS) stream solute transport model to quantify the physical transport mechanisms. The downstream transport of fulvic acid as indicated by absorbance was then simulated using OTIS with a first-order kinetic sorption rate constant applied to the sorbable fulvic acid. The "sorbable" fraction of injected fulvic acid was irreversibly sorbed by streambed sediments at rates (kinetic rate constants) of the order of 10-4-10-3 S-1. In the injected Suwannee River water, sorbable and nonsorbable fulvic acid had distinct chemical characteristics identified in 13C-NMR spectra. The 13C-NMR spectra indicate that during the experiment, the sorbable "signal" of greater aromaticity and carboxyl content decreased downstream; that is, these components were preferentially removed. This study illustrates that interactions between the water and the reactive surfaces will modify significantly the concentration and composition of DOC observed in streams with abundant chemically reactive surfaces on the streambed and in the hyporheic zone.

  3. Landuse legacies and small streams: Identifying relationships between historical land use and contemporary stream conditions

    USGS Publications Warehouse

    Maloney, K.O.; Feminella, J.W.; Mitchell, R.M.; Miller, S.A.; Mulholland, P.J.; Houser, J.N.

    2008-01-01

    The concept of landscape legacies has been examined extensively in terrestrial ecosystems and has led to a greater understanding of contemporary ecosystem processes. However, although stream ecosystems are tightly coupled with their catchments and, thus, probably are affected strongly by historical catchment conditions, few studies have directly examined the importance of landuse legacies on streams. We examined relationships between historical land use (1944) and contemporary (2000-2003) stream physical, chemical, and biological conditions after accounting for the influences of contemporary land use (1999) and natural landscape (catchment size) variation in 12 small streams at Fort Benning, Georgia, USA. Most stream variables showed strong relationships with contemporary land use and catchment size; however, after accounting for these factors, residual variation in many variables remained significantly related to historical land use. Residual variation in benthic particulate organic matter, diatom density, % of diatoms in Eunotia spp., fish density in runs, and whole-stream gross primary productivity correlated negatively, whereas streamwater pH correlated positively, with residual variation in fraction of disturbed land in catchments in 1944 (i.e., bare ground and unpaved road cover). Residual variation in % recovering land (i.e., early successional vegetation) in 1944 was correlated positively with residual variation in streambed instability, a macroinvertebrate biotic index, and fish richness, but correlated negatively with residual variation in most benthic macroinvertebrate metrics examined (e.g., Chironomidae and total richness, Shannon diversity). In contrast, residual variation in whole-stream respiration rates was not explained by historical land use. Our results suggest that historical land use continues to influence important physical and chemical variables in these streams, and in turn, probably influences associated biota. Beyond providing insight into biotic interactions and their associations with environmental conditions, identification of landuse legacies also will improve understanding of stream impairment in contemporary minimally disturbed catchments, enabling more accurate assessment of reference conditions in studies of biotic integrity and restoration. ?? 2008 by The North American Benthological Society.

  4. Stream primary producers relate positively to watershed natural gas measures in north-central Arkansas streams.

    PubMed

    Austin, Bradley J; Hardgrave, Natalia; Inlander, Ethan; Gallipeau, Cory; Entrekin, Sally; Evans-White, Michelle A

    2015-10-01

    Construction of unconventional natural gas (UNG) infrastructure (e.g., well pads, pipelines) is an increasingly common anthropogenic stressor that increases potential sediment erosion. Increased sediment inputs into nearby streams may decrease autotrophic processes through burial and scour, or sediment bound nutrients could have a positive effect through alleviating potential nutrient limitations. Ten streams with varying catchment UNG well densities (0-3.6 wells/km(2)) were sampled during winter and spring of 2010 and 2011 to examine relationships between landscape scale disturbances associated with UNG activity and stream periphyton [chlorophyll a (Chl a)] and gross primary production (GPP). Local scale variables including light availability and water column physicochemical variables were measured for each study site. Correlation analyses examined the relationships of autotrophic processes and local scale variables with the landscape scale variables percent pasture land use and UNG metrics (well density and well pad inverse flow path length). Both GPP and Chl a were primarily positively associated with the UNG activity metrics during most sample periods; however, neither landscape variables nor response variables correlated well with local scale factors. These positive correlations do not confirm causation, but they do suggest that it is possible that UNG development can alleviate one or more limiting factors on autotrophic production within these streams. A secondary manipulative study was used to examine the link between nutrient limitation and algal growth across a gradient of streams impacted by natural gas activity. Nitrogen limitation was common among minimally impacted stream reaches and was alleviated in streams with high UNG activity. These data provide evidence that UNG may stimulate the primary production of Fayetteville shale streams via alleviation of N-limitation. Restricting UNG activities from the riparian zone along with better enforcement of best management practices should help reduce these possible impacts of UNG activities on stream autotrophic processes. PMID:26005749

  5. Utilizing the Cyberforest live sound system with social media to remotely conduct woodland bird censuses in Central Japan.

    PubMed

    Saito, Kaoru; Nakamura, Kazuhiko; Ueta, Mutsuyuki; Kurosawa, Reiko; Fujiwara, Akio; Kobayashi, Hill Hiroki; Nakayama, Masaya; Toko, Ayako; Nagahama, Kazuyo

    2015-11-01

    We have developed a system that streams and archives live sound from remote areas across Japan via an unmanned automatic camera. The system was used to carry out pilot bird censuses in woodland; this allowed us to examine the use of live sound transmission and the role of social media as a mediator in remote scientific monitoring. The system has been streaming sounds 8h per day for more than fiveyears. We demonstrated that: (1) the transmission of live sound from a remote woodland could be used effectively to monitor birds in a remote location; (2) the simultaneous involvement of several participants via Internet Relay Chat to listen to live sound transmissions could enhance the accuracy of census data collection; and (3) interactions through Twitter allowed members of the public to engage or help with the remote monitoring of birds and experience inaccessible nature through the use of novel technologies. PMID:26508345

  6. The living publication

    SciTech Connect

    Terwilliger, Thomas C.

    2012-06-04

    Within the ICSTI Insights Series we offer three articles on the 'living publication' that is already available to practitioners in the important field of crystal structure determination and analysis. While the specific examples are drawn from this particular field, we invite readers to draw parallels in their own fields of interest. The first article describes the present state of the crystallographic living publication, already recognized by an ALPSP (Association of Learned and Professional Society Publishers) Award for Publishing Innovation in 2006. The second article describes the potential impact on the record of science as greater post-publication analysis becomes more common within currently accepted data deposition practices, using processed diffraction data as the starting point. The third article outlines a vision for the further improvement of crystallographic structure reports within potentially achievable enhanced data deposition practices, based upon raw (unprocessed) diffraction data. The IUCr in its Commissions and Journals has for many years emphasized the importance of publications being accompanied by data and the interpretation of the data in terms of atomic models. This has been followed as policy by numerous other journals in the field and its cognate disciplines. This practice has been well served by databases and archiving institutions such as the Protein Data Bank (PDB), the Cambridge Crystallographic Data Centre (CCDC), and the Inorganic Crystal Structure Database (ICSD). Normally the models that are archived are interpretations of the data, consisting of atomic coordinates with their displacement parameters, along with processed diffraction data from X-ray, neutron or electron diffraction studies. In our current online age, a reader can not only consult the printed word, but can display and explore the results with molecular graphics software of exceptional quality. Furthermore, the routine availability of processed diffraction data allows readers to perform direct calculations of the electron density (using X-rays and electrons as probes) or the nuclear density (using neutrons as probe) on which the molecular models are directly based. This current community practice is described in our first article. There are various ways that these data and tools can be used to further analyze the molecules that have been crystallized. Notably, once a set of results is announced via the publication, the research community can start to interact directly with the data and models. This gives the community the opportunity not only to read about the structure, but to examine it in detail, and even generate subsequent improved models. These improved models could, in principle, be archived along with the original interpretation of the data and can represent a continuously improving set of interpretations of a set of diffraction data. The models could improve both by correction of errors in the original interpretation and by the use of new representations of molecules in crystal structures that more accurately represent the contents of a crystal. These possible developments are described in our second article. A current, significant, thrust for the IUCr is whether it would be advantageous for the crystallographic community to require, rather than only encourage, the archiving of the raw (unprocessed) diffraction data images measured from a crystal, a fibre or a solution. This issue is being evaluated in detail by an IUCr Working Group (see http://forums.iucr.org). Such archived raw data would be linked to and from any associated publications. The archiving of raw diffraction data could allow as yet undeveloped processing methods to have access to the originally measured data. The debate within the community about this much larger proposed archiving effort revolves around the issue of 'cost versus benefit'. Costs can be minimized by preserving the raw data in local repositories, either at centralized synchrotron and neutron research institutes, or at research universities. Archiving raw data is also perceived as being more effective than just archiving processed data in countering scientific fraud, which exists in our field, albeit at a tiny level of occurrences. In parallel developments, sensitivities to avoiding research malpractice are encouraging Universities to establish their own data repositories for research and academic staff. These various 'raw data archives', would complement the existing processed data archives. These archives could however have gaps in their coverage arising from a lack of resources. Nevertheless we believe that a sufficiently large raw data archive, with reasonable global coverage, could be encouraged and have major benefits. These possible developments, costs and benefits, are described in our third and final article on 'The living publication'.

  7. Designing stream restoration structures using 3D hydro-morphodynamic numerical modeling

    NASA Astrophysics Data System (ADS)

    Khosronejad, A.; Kozarek, J. L.; Hill, C.; Kang, S.; Plott, R.; Diplas, P.; Sotiropoulos, F.

    2012-12-01

    Efforts to stabilize and restore streams and rivers across the nation have grown dramatically in the last fifteen years, with over $1 billion spent every year since 1990. The development of effective and long-lasting strategies, however, is far from trivial and despite large investments it is estimated that at least 50% of stream restoration projects fail. This is because stream restoration is today more of an art than a science. The lack of physics-based engineering standards for stream restoration techniques is best underscored in the design and installation of shallow, in-stream, low-flow structures, which direct flow away from the banks, protect stream banks from erosion and scour, and increase habitat diversity. Present-day design guidelines for such in-stream structures are typically vague and rely heavily on empirical knowledge and intuition rather than physical understanding of the interactions of the structures the flow and sediment transport processes in the waterway. We have developed a novel computer-simulation based paradigm for designing in stream structures that is based on state-of-the-art 3D hydro-morphodynamic modeling validated with laboratory and field-scale experiments. The numerical model is based on the Curvilinear Immersed Boundary (CURVIB) approach of Kang et al. and Khosronejad et al. (Adv. in Water Res. 2010, 2011), which can simulate flow and sediment transport processes in arbitrarily complex waterways with embedded rock structures. URANS or large-eddy simulation (LES) models are used to simulate turbulence. Transport of bed materials is simulated using the non-equilibrium Exner equation for the bed surface elevation coupled with a transport equation for suspended load. Extensive laboratory and field-scale experiments have been carried out and employed to validate extensively the computational model. The numerical model is used to develop a virtual testing environment within which one or multiple in-stream structures can be embedded in representative live-bed meandering waterways and simulated numerically to systematically investigate the sensitivity of various design and installation parameters on structure performance and reliability. Waterway geometries are selected by a statistical classification of rivers and streams to represent typical sand-bed and gravel-bed systems found in nature. Results will be presented for rock vanes, J-hook vanes and bendway weirs. Our findings provide novel physical insights into the effects of various in-stream structures on turbulent flow and sediment transport processes in meandering rivers, underscore these effects for different stream-bed materials, and demonstrate how such physics-based analysis can yield design guidelines that often challenge what is commonly done in practice today. To our knowledge, our work is the first systematic attempt to employ advanced numerical modeling coupled with massively parallel supercomputers to design hydraulic structures for stream restoration. This work was supported by NSF Grants EAR-0120914 and EAR-0738726, National Cooperative Highway Research Program Grant NCHRP-HR 24-33.

  8. StreamNet Project : Annual Report Fiscal Year 2008.

    SciTech Connect

    Schmidt, Bruce; Roger, Phil; Oftedahl, Lenora

    2008-12-12

    Fiscal Year 2008 (FY-08) represents a transitional year for the StreamNet project. While the project continued to acquire/update, standardize, georeference and disseminate fish-related data for the state, some tribal and one federal fisheries agencies, it also took on several new initiatives and is anticipating new regional guidance on data needs. Passage of the Columbia Basin Accords caused an administrative change within the project, separating the work done by the Columbia River Inter-Tribal Fish Commission (CRITFC) out to a separate contract with BPA. This will change the structure of the StreamNet contract but not change the relationship with the StreamNet Library or data developed by CRITFC, and will likely increase the availability of tribal data to StreamNet due to increased funding for tribal data efforts. This change will take effect in FY-09. We also expect that data work will be adjusted in the future in response to executive level policy direction in the Columbia Basin based on efforts to establish priorities under a regional data management framework. Data development emphasis was shifted this year to place highest priority on data that support indicators of fish abundance for the focal species covered in the Status of the Resource (SOTR) report, as requested by the Columbia Basin Fish and Wildlife Authority (CBFWA) Data Management Framework Subcommittee. We instituted an XML based web service allowing direct access to data from the project database for CBFWA to update the SOTR report. The project also increased efforts to work with tribal fisheries managers to provide data related assistance and to include tribal data in the StreamNet database. A primary theme this year was exploring means to speed the flow of data. We had ongoing success in our strategic emphasis on increasing automation of data conversion through development of comprehensive database systems within our partner agencies, as outlined in our Vision and Strategic Plan. By assisting development of internal database systems, we will be able to automate conversion of agency data to the regionally consistent format as well as help the agency better meet their own data needs. The Idaho StreamNet project contributed to development of IDFG's Idaho Fish and Wildlife Information System (IFWIS), and this year they successfully tested automatic conversion of data to the regional exchange format. We worked with WDFW and developed draft field data input templates for collection of smolt trap and spawning ground survey data. And, we began collaborating in a project with ODFW and EcoTrust to develop an online data dissemination tool. As these and additional data systems are brought online, we expect to be able to shorten the time needed to annually update data, and hope to use the increased efficiency to free existing staff time to develop additional types of data from our partners. Another long-term theme related to expanding data coverage to estimates of productivity and/or data needed to calculate productivity. Initial investigations within our partner agencies indicated that these data are scattered, with some components like age composition of returning fish already being addressed by StreamNet, but others not yet covered. We will continue to determine how available these data are and investigate the feasibility of capturing the estimates and supporting data in the future. Routine ongoing data development of the standard data sets in StreamNet continued this year. An update and new web page for disseminating Protected Areas data was completed. Initial work was done with the CRITFC to get ready to house and disseminate data developed by the Hatchery Scientific Review Group. All database, GIS and web server systems were maintained successfully, with repairs completed as needed. Software applications were developed or maintained, as needed. All required reports, budgets and equipment inventories were submitted. The StreamNet website (www.streamnet.org), the project's primary means of disseminating fish data, was completely redesigned this year to improve the user experience and make locating and acquiring data simpler. A primary goal was to significantly reduce the sequence of steps needed. The new site was in final testing at the end of the fiscal year, and will go live in the first quarter of FY-09. Use of the website remained strong, with 941,687 total page views representing 345,855 visits from 123,684 unique visitors. There were 18,797 actual views of tabular datasets from the online query system, plus many interactive map views, not counting downloads of the entire database direct data and information requests.

  9. Combined influence of unsteady free stream velocity and free stream turbulence on stagnation point heat transfer

    NASA Technical Reports Server (NTRS)

    Gorla, R. S. R.

    1984-01-01

    An analysis is presented to study the combined effects of transient free stream velocity and free stream turbulence on heat transfer at a stagnation point over a cylinder situated in a crossflow. An expression for the eddy diffusivity has been formulated and the governing momentum and energy equations are integrated by means of the steepest descent method. The numerical results for the heat transfer rate are correlated by a turbulence parameter. It has been found that the stagnation point heat transfer rate increases with increasing free stream turbulence intensity.

  10. Stream invertebrate productivity linked to forest subsidies: 37 stream-years of reference and experimental data.

    PubMed

    Wallace, J Bruce; Eggert, Susan L; Meyer, Judy L; Webster, Jackson R

    2015-05-01

    Riparian habitats provide detrital subsidies of varying quantities and qualities to recipient ecosystems. We used long-term data from three reference streams (covering 24 stream-years) and 13-year whole-stream organic matter manipulations to investigate the influence of terrestrial detrital quantity and quality on benthic invertebrate community structure, abundance, biomass, and secondary production in rockface (RF) and mixed substrates (MS) of forested headwater streams. Using a mesh canopy covering the entire treatment stream, we examined effects of litter ex'clusion, small- and large-wood removal, and addition of artificial wood (PVC) and leaves of varying quality on organic matter standing crops and invertebrate community structure and function. We assessed differences in functional feeding group distribution between substrate types as influenced by organic matter manipulations and long-term patterns of predator and prey production in manipulated vs. reference years. Particulate organic matter standing crops in MS of the treatment stream declined drastically with each successive year of litter exclusion, approaching zero after three years. Monthly invertebrate biomass and annual secondary production was positively related to benthic organic matter in the MS habitats. Rockface habitats exhibited fewer changes than MS habitats across all organic matter manipulations. With leaf addition, the patterns of functional group distribution among MS and RF habitats returned to patterns seen in reference streams. Secondary production per unit organic matter standing crop was greatest for the leaf addition period, followed by the reference streams, and significantly less for the litter exclusion and wood removal periods. These data indicate that the limited organic matter remaining in the stream following litter exclusion and wood removal was more refractory than that in the reference streams, whereas the added leaf material was more labile and readily converted into invertebrate production. Predator production and total production were tightly coupled in reference and treatment streams, indicating strong relationships between predators and their prey. Results from the artificial wood addition demonstrate that physical structure alone will not restore invertebrate productivity without detrital resources from the riparian forest. Our long-term studies conducted over three decades at the ecosystem scale unequivocally show the necessity of maintaining and restoring aquatic-terrestrial linkages in forested headwater streams. PMID:26236836

  11. Nitrous oxide emissions from streams within the US Corn Belt scale with stream order

    NASA Astrophysics Data System (ADS)

    Turner, P. A.; Griffis, T. J.; Lee, X.; Baker, J. M.; Venterea, R. T.; Wood, J. D.

    2014-12-01

    Nitrous oxide (N2O) is an important greenhouse gas and the primary stratospheric ozone depleting substance. Agriculture is the main source of N2O emissions as a result of high nitrogen (N) fertilizer inputs. The Intergovernmental Panel on Climate Change (IPCC) uses bottom-up emission factors (EFs) to estimate annual emissions from direct and indirect sources. Top-down N2O emission estimates based on independent tall tower observations indicate that bottom-up approaches severely underestimate the annual budget at the regional scale. It is well established that indirect N2O emissions from streams are poorly characterized due to a scarcity of observations, poorly constrained piston velocity relationships, and high variability among surface water types. Indirect emissions from streams represent a large source of uncertainty in the global N2O budget. Here we examine the extent to which indirect emissions from streams contribute to the regional budget and propose a strategy for scaling up indirect emissions based on stream order relations. Two years of floating chamber-based flux measurements showed that N2O emissions from headwater streams (drainage ditches) in an agricultural landscape often exceeded 45 nmol N2O m-2 s-1 and decreased exponentially as a function of stream order. This scaling function was used to estimate indirect emissions for the region and indicated that the IPCC EF5r significantly underestimated the observed emissions within a representative watershed of the US Corn Belt in the Midwestern United States. Headwater streams and rivers contributed ~75% and <1% respectively to the watershed indirect N2O budget, highlighting the need to better constrain low order stream system emissions. Furthermore, instantaneous fluxes from high order streams were well constrained and significantly smaller than low order streams. Consequently, a single EF for all streams and rivers does not appear to be appropriate. Our findings suggest that bottom-up models likely underestimate N2O emissions in the US Corn Belt in part because low order stream emissions are underestimated.

  12. EFFECTS OF WATERSHED DISTURBANCE ON SMALL STREAMS

    EPA Science Inventory

    This presentation presents the effects of watershed disturbance on small streams. The South Fork Broad River Watershed was studied to evaluate the use of landscape indicators to predict pollutant loading at small spatial scales and to develop indicators of pollutants. Also studie...

  13. Stream Hydrological Fragmentation Drives Bacterioplankton Community Composition

    PubMed Central

    Fazi, Stefano; Vzquez, Eusebi; Casamayor, Emilio O.; Amalfitano, Stefano; Butturini, Andrea

    2013-01-01

    In Mediterranean intermittent streams, the hydrological fragmentation in summer and the successive water flow re-convergence in autumn allow exploring how local processes shape the microbial community within the same habitat. The objectives of this study were to determine how bacterial community composition responded to hydrological fragmentation in summer, and to evaluate whether the seasonal shifts in community composition predominate over the effects of episodic habitat fragmentation. The bacterial community was assessed along the intermittent stream Fuirosos (Spain), at different levels of phylogenetic resolution by in situ hybridization, fingerprinting, and 16S rRNA gene sequencing. The hydrological fragmentation of the stream network strongly altered the biogeochemical conditions with the depletion of oxidized solutes and caused changes in dissolved organic carbon characteristics. In the isolated ponds, beta-Proteobacteria and Actinobacteria increased their abundance with a gradual reduction of the alpha-diversity as pond isolation time increased. Moreover, fingerprinting analysis clearly showed a shift in community composition between summer and autumn. In the context of a seasonal shift, the temporary stream fragmentation simultaneously reduced the microbial dispersion and affected local environmental conditions (shift in redox regime and quality of the dissolved organic matter) tightly shaping the bacterioplankton community composition. PMID:23741302

  14. Disc valve for sampling erosive process streams

    DOEpatents

    Mrochek, J.E.; Dinsmore, S.R.; Chandler, E.W.

    1984-08-16

    This is a patent for a disc-type, four-port sampling valve for service with erosive high temperature process streams. Inserts and liners of ..cap alpha..-silicon carbide respectively, in the faceplates and in the sampling cavities, limit erosion while providing lubricity for a smooth and precise operation. 1 fig.

  15. The Experimental Stream Facility, Clermont County, Ohio

    EPA Science Inventory

    A watershed is the natural land area that drains into a common waterway, such as a stream, lake, estuary, wetland, aquifer, or even the ocean. Watersheds are importantthey supply drinking water, provide recreation, and sustain life. So its also important to reduce the loading ...

  16. ECOSYSTEM EFFECTS OF URBAN STREAM RESTORATION

    EPA Science Inventory

    In general, the ecosystem function of a restored site will depend upon how degraded the site was prior to restoration and to what extent this was addressed in the restoration design. A stream whose primary impairment is severe water quality problems due to non-point source po...

  17. Measurement of Cytoplasmic Streaming in Drosophila Melanogaster

    NASA Astrophysics Data System (ADS)

    Ganguly, Sujoy; Williams, Lucy; Palacios, Isabel; Goldstein, Raymond

    2010-11-01

    During stage 9 of Drosophila melanogastor oogenesis flow of the oocyte cytoplasm, driven by kinesin 1 motor protein is observed. This cytoplasmic streaming is analyzed by PIV in both wild type and kinesin light chain mutants, revealing striking statistical differences. Further measurements of the rheology of the oocyte allow for estimations of the mechanical energy needed to generate the observed flows.

  18. Hydrothermal carbonization of municipal waste streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrothermal carbonization (HTC) is a novel thermal conversion process that can be used to convert municipal waste streams into sterilized, value-added hydrochar. HTC has been mostly applied and studied on a limited number of feedstocks, ranging from pure substances to slightly more complex biomass ...

  19. Stream temperature response to glacier retreat (Invited)

    NASA Astrophysics Data System (ADS)

    Moore, R. D.

    2013-12-01

    Stream temperature is a fundamental aspect of aquatic habitat, and there has been increasing concern in recent years that climatic change and glacier retreat will result in increased water temperatures, with potentially negative influences on cold and cool water species such as salmonids. A statistical model was developed to predict the maximum weekly average stream temperature based on data from 418 sites located throughout British Columbia, Canada. Catchment-scale glacier coverage was a significant predictor in the model, and example calculations indicate that plausible decreases in glacier coverage over the next few decades have the potential to result in warming that would be sufficient to cause shifts in fish species assemblages. However, this space-for-time substitution rests on assumptions that may not be valid, especially in the context of a changing climate, leading to a need to develop and apply physically based models. Reach-scale energy budget analyses indicate that parameterizations of energy fluxes used in current stream temperature models are not appropriate for steep channels with cascading flow. In particular, the sensible and latent heat fluxes are more efficient than in lower-gradient channels, and the albedo is enhanced by aeration. Over longer time scales, development of riparian forest has the potential to mitigate the effect of glacier retreat in alpine areas by shading the stream, but it may take centuries for functional riparian forest to develop at higher elevation sites.

  20. Gelatin Plasticized with a Biodiesel Coproduct Stream

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cast gelatin films were plasticized with a biodiesel coproduct stream (BCS). Gelatin was found to be compatible with the non-glycerol components of BCS. Films were well formed and appeared homogeneous on the macroscopic level. A BCS content of 1834% resulted in elongations of 35182%, with correspo...