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Sample records for aggregate remote memory

  1. Remote direct memory access

    DOEpatents

    Archer, Charles J.; Blocksome, Michael A.

    2012-12-11

    Methods, parallel computers, and computer program products are disclosed for remote direct memory access. Embodiments include transmitting, from an origin DMA engine on an origin compute node to a plurality target DMA engines on target compute nodes, a request to send message, the request to send message specifying a data to be transferred from the origin DMA engine to data storage on each target compute node; receiving, by each target DMA engine on each target compute node, the request to send message; preparing, by each target DMA engine, to store data according to the data storage reference and the data length, including assigning a base storage address for the data storage reference; sending, by one or more of the target DMA engines, an acknowledgment message acknowledging that all the target DMA engines are prepared to receive a data transmission from the origin DMA engine; receiving, by the origin DMA engine, the acknowledgement message from the one or more of the target DMA engines; and transferring, by the origin DMA engine, data to data storage on each of the target compute nodes according to the data storage reference using a single direct put operation.

  2. High Performance Remote Memory Access Communication: The ARMCI Approach

    SciTech Connect

    Nieplocha, Jarek; Tipparaju, Vinod; Krishnan, Manoj Kumar; Panda, Dhabaleswar K.

    2006-07-01

    This paper describes the Aggregate Remote Memory Copy Interface (ARMCI), a portable high performance remote memory access (RMA) communication interface, developed originally under the DoE-2000 ACTS Toolkit project and currently used as a part of the run-time layer of the DoE project Programming Models for Scalable Parallel Computing. The paper discusses the model, portable implementation, and performance of ARMCI. Special emphasis is placed on the latency hiding mechanisms and ability to optimize noncontiguous data transfers.

  3. Neural mechanism underlying autobiographical memory modulated by remoteness and emotion

    NASA Astrophysics Data System (ADS)

    Ge, Ruiyang; Fu, Yan; Wang, DaHua; Yao, Li; Long, Zhiying

    2012-03-01

    Autobiographical memory is the ability to recollect past events from one's own life. Both emotional tone and memory remoteness can influence autobiographical memory retrieval along the time axis of one's life. Although numerous studies have been performed to investigate brain regions involved in retrieving processes of autobiographical memory, the effect of emotional tone and memory age on autobiographical memory retrieval remains to be clarified. Moreover, whether the involvement of hippocampus in consolidation of autobiographical events is time dependent or independent has been controversial. In this study, we investigated the effect of memory remoteness (factor1: recent and remote) and emotional valence (factor2: positive and negative) on neural correlates underlying autobiographical memory by using functional magnetic resonance imaging (fMRI) technique. Although all four conditions activated some common regions known as "core" regions in autobiographical memory retrieval, there are some other regions showing significantly different activation for recent versus remote and positive versus negative memories. In particular, we found that bilateral hippocampal regions were activated in the four conditions regardless of memory remoteness and emotional valence. Thus, our study confirmed some findings of previous studies and provided further evidence to support the multi-trace theory which believes that the role of hippocampus involved in autobiographical memory retrieval is time-independent and permanent in memory consolidation.

  4. Remote direct memory access over datagrams

    DOEpatents

    Grant, Ryan Eric; Rashti, Mohammad Javad; Balaji, Pavan; Afsahi, Ahmad

    2014-12-02

    A communication stack for providing remote direct memory access (RDMA) over a datagram network is disclosed. The communication stack has a user level interface configured to accept datagram related input and communicate with an RDMA enabled network interface card (NIC) via an NIC driver. The communication stack also has an RDMA protocol layer configured to supply one or more data transfer primitives for the datagram related input of the user level. The communication stack further has a direct data placement (DDP) layer configured to transfer the datagram related input from a user storage to a transport layer based on the one or more data transfer primitives by way of a lower layer protocol (LLP) over the datagram network.

  5. Stability of Recent and Remote Contextual Fear Memory

    ERIC Educational Resources Information Center

    Frankland, Paul W.; Ding, Hoi-Ki; Takahashi, Eiki; Suzuki, Akinobu; Kida, Satoshi; Silva, Alcino J.

    2006-01-01

    Following initial encoding, memories undergo a prolonged period of reorganization. While such reorganization may occur in many different memory systems, its purpose is not clear. Previously, we have shown that recall of recent contextual fear memories engages the dorsal hippocampus (dHPC). In contrast, recall of remote contextual fear memories…

  6. The effect of cortisol on autobiographical memory retrieval depends on remoteness and valence of memories.

    PubMed

    Fleischer, Juliane; Weber, Juliane; Hellmann-Regen, Julian; Düsenberg, Moritz; Wolf, Oliver T; Otte, Christian; Wingenfeld, Katja

    2017-02-01

    There is evidence that specificity of autobiographical memory (AM) retrieval is impaired by cortisol. However, it is unknown whether glucocorticoids differentially influence the retrieval of recent versus remote AMs. Therefore, the aim of the current study was to investigate the effects of cortisol on AM retrieval, in terms of memory specificity, with respect to remoteness of the retrieved memories. A placebo controlled, double blind study was conducted. Thirty female and 24 male healthy participants (mean age 24.5, SD=3.7) received either placebo or 10mg hydrocortisone before completing an autobiographical memory test. Participants showed higher memory specificity for recent memories compared to remote ones. There was no main effect of cortisol on AM retrieval. However, interaction effects suggest that cortisol affects remote, but not recent memories, which seems to depend upon valence.

  7. Convex aggregative modelling of infinite memory nonlinear systems

    NASA Astrophysics Data System (ADS)

    Wachel, Paweł

    2016-08-01

    The convex aggregation technique is applied for modelling general class of nonlinear systems with unknown structure and infinite memory. The finite sample size properties of the algorithm are formally established and compared to the standard least-squares counterpart of the method. The proposed algorithm demonstrates its advantages when the a-priori knowledge and the measurement data are both scarce, that is, when the information about the actual system structure is unknown or uncertain and the measurement set is small and disturbed by a noise. Numerical experiments illustrate application and practical benefits of the method for various nonlinear systems.

  8. Epigenetic Priming of Memory Updating during Reconsolidation to Attenuate Remote Fear Memories

    PubMed Central

    Gräff, Johannes; Joseph, Nadine F.; Horn, Meryl E.; Samiei, Alireza; Meng, Jia; Seo, Jinsoo; Rei, Damien; Bero, Adam W.; Phan, Trongha X.; Wagner, Florence; Holson, Edward; Xu, Jinbin; Sun, Jianjun; Neve, Rachael L.; Mach, Robert H.; Haggarty, Stephen J.; Tsai, Li-Huei

    2014-01-01

    Summary Traumatic events generate some of the most enduring forms of memories. Despite the elevated lifetime prevalence of anxiety disorders, effective strategies to attenuate long-term traumatic memories are scarce. The most efficacious treatments to diminish recent (i.e., day-old) traumata capitalize on memory updating mechanisms during reconsolidation that are initiated upon memory recall. Here, we show that, in mice, successful reconsolidation-updating paradigms for recent memories fail to attenuate remote (i.e., month-old) ones. We find that, whereas recent memory recall induces a limited period of hippocampal neuroplasticity mediated, in part, by S-nitrosylation of HDAC2 and histone acetylation, such plasticity is absent for remote memories. However, by using an HDAC2-targeting inhibitor (HDACi) during reconsolidation, even remote memories can be persistently attenuated. This intervention epigenetically primes the expression of neuroplasticity-related genes, which is accompanied by higher metabolic, synaptic, and structural plasticity. Thus, applying HDACis during memory reconsolidation might constitute a treatment option for remote traumata. PMID:24439381

  9. New developments in sampling and aggregation for remotely sensed surveys

    NASA Technical Reports Server (NTRS)

    Feiveson, A. H. (Principal Investigator)

    1979-01-01

    Sampling techniques used to construct large area crop estimates are briefly reviewed. Problem areas in sampling and aggregation are covered. The natural sampling strategy, two phase sampling, weighted aggregation, and multiyear estimation are among the topics discussed.

  10. Exploiting Nonblocking Remote Memory Access Communication in Scientific Benchmarks

    SciTech Connect

    Tipparaju, Vinod; Krishnan, Manoj Kumar; Nieplocha, Jarek; Santhanaraman, Gopalakrishnan; Panda, Dhabaleswar K.

    2004-12-07

    In the last decade message passing has become the predominant programming model for scientific applications. The current paper attempts to answer the question to what degree performance of well tuned application benchmarks coded in MPI can be improved by using another related programming model, remote memory access (RMA) communication.

  11. Extinction Partially Reverts Structural Changes Associated with Remote Fear Memory

    ERIC Educational Resources Information Center

    Vetere, Gisella; Restivo, Leonardo; Novembre, Giovanni; Aceti, Massimiliano; Lumaca, Massimo; Ammassari-Teule, Martine

    2011-01-01

    Structural synaptic changes occur in medial prefrontal cortex circuits during remote memory formation. Whether extinction reverts or further reshapes these circuits is, however, unknown. Here we show that the number and the size of spines were enhanced in anterior cingulate (aCC) and infralimbic (ILC) cortices 36 d following contextual fear…

  12. Remote semantic memory is impoverished in hippocampal amnesia.

    PubMed

    Klooster, Nathaniel B; Duff, Melissa C

    2015-12-01

    The necessity of the hippocampus for acquiring new semantic concepts is a topic of considerable debate. However, it is generally accepted that any role the hippocampus plays in semantic memory is time limited and that previously acquired information becomes independent of the hippocampus over time. This view, along with intact naming and word-definition matching performance in amnesia, has led to the notion that remote semantic memory is intact in patients with hippocampal amnesia. Motivated by perspectives of word learning as a protracted process where additional features and senses of a word are added over time, and by recent discoveries about the time course of hippocampal contributions to on-line relational processing, reconsolidation, and the flexible integration of information, we revisit the notion that remote semantic memory is intact in amnesia. Using measures of semantic richness and vocabulary depth from psycholinguistics and first and second language-learning studies, we examined how much information is associated with previously acquired, highly familiar words in a group of patients with bilateral hippocampal damage and amnesia. Relative to healthy demographically matched comparison participants and a group of brain-damaged comparison participants, the patients with hippocampal amnesia performed significantly worse on both productive and receptive measures of vocabulary depth and semantic richness. These findings suggest that remote semantic memory is impoverished in patients with hippocampal amnesia and that the hippocampus may play a role in the maintenance and updating of semantic memory beyond its initial acquisition.

  13. Remote semantic memory is impoverished in hippocampal amnesia

    PubMed Central

    Klooster, Nathaniel B.; Duff, Melissa C.

    2015-01-01

    The necessity of the hippocampus for acquiring new semantic concepts is a topic of considerable debate. However, it is generally accepted that any role the hippocampus plays in semantic memory is time limited and that previously acquired information becomes independent of the hippocampus over time. This view, along with intact naming and word-definition matching performance in amnesia, has led to the notion that remote semantic memory is intact in patients with hippocampal amnesia. Motivated by perspectives of word learning as a protracted process where additional features and senses of a word are added over time, and by recent discoveries about the time course of hippocampal contributions to on-line relational processing, reconsolidation, and the flexible integration of information, we revisit the notion that remote semantic memory is intact in amnesia. Using measures of semantic richness and vocabulary depth from psycholinguistics and first and second language-learning studies, we examined how much information is associated with previously acquired, highly familiar words in a group of patients with bilateral hippocampal damage and amnesia. Relative to healthy demographically matched comparison participants and a group of brain-damaged comparison participants, the patients with hippocampal amnesia performed significantly worse on both productive and receptive measures of vocabulary depth and semantic richness. These findings suggest that remote semantic memory is impoverished in patients with hippocampal amnesia and that the hippocampus may play a role in the maintenance and updating of semantic memory beyond its initial acquisition. PMID:26474741

  14. A study of remote spatial memory in aged rats.

    PubMed

    Winocur, Gordon; Moscovitch, Morris; Rosenbaum, R Shayna; Sekeres, Melanie

    2010-01-01

    The effect of aging on remote spatial memory was tested in a group of 2-year-old rats (VR-O) that, as young adults, were reared for 3 months in a complex 'village' environment. The VR-O rats exhibited significant savings in finding the locations of specific reward compartments within the village, relative to a group of old rats (VNR-O) experiencing the village for the first time. The VNR-O rats were also impaired, relative to naive young rats, in learning the reward locations. Probe tests indicated that the VR-O rats retained allocentric spatial memory for the environment and were not using sensory or other non-spatial cues to guide behaviour. Overall, the results indicate that the aged rats experienced a decline in the ability to learn and remember detailed spatial relationships and that the VR-O group's successful performance on the remote spatial memory test was guided by a form of schematic memory that captured the essential features of the village environment. The potential contribution of the hippocampus to the pattern of lost and spared learning and memory observed in the aged rats was discussed.

  15. Performance Evaluation of Remote Memory Access (RMA) Programming on Shared Memory Parallel Computers

    NASA Technical Reports Server (NTRS)

    Jin, Hao-Qiang; Jost, Gabriele; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    The purpose of this study is to evaluate the feasibility of remote memory access (RMA) programming on shared memory parallel computers. We discuss different RMA based implementations of selected CFD application benchmark kernels and compare them to corresponding message passing based codes. For the message-passing implementation we use MPI point-to-point and global communication routines. For the RMA based approach we consider two different libraries supporting this programming model. One is a shared memory parallelization library (SMPlib) developed at NASA Ames, the other is the MPI-2 extensions to the MPI Standard. We give timing comparisons for the different implementation strategies and discuss the performance.

  16. A survey of natural aggregate properties and characteristics important in remote sensing and airborne geophysics

    USGS Publications Warehouse

    Knepper, D.H.; Langer, W.H.; Miller, S.

    1995-01-01

    Natural aggregate is vital to the construction industry. Although natural aggregate is a high volume/low value commodity that is abundant, new sources are becoming increasingly difficult to find and develop because of rigid industry specifications, political considerations, development and transportation costs, and environmental concerns. There are two primary sources of natural aggregate: (1) exposed or near-surface bedrock that can be crushed, and (2) deposits of sand and gravel. Remote sensing and airborne geophysics detect surface and near-surface phenomena, and may be useful for detecting and mapping potential aggregate sources; however, before a methodology for applying these techniques can be developed, it is necessary to understand the type, distribution, physical properties, and characteristics of natural aggregate deposits. The distribution of potential aggregate sources is closely tied to local geologic history. Conventional exploration for natural aggregate deposits has been largely a ground-based operation, although aerial photographs and topographic maps have been extensively used to target possible deposits. Today, the exploration process also considers factors such as the availability of the land, space and water supply for processing, political and environmental factors, and distance from the market; exploration and planning cannot be separated. There are many physical properties and characteristics by which to judge aggregate material for specific applications; most of these properties and characteristics pertain only to individual aggregate particles. The application of remote sensing and airborne geophysical measurements to detecting and mapping potential aggregate sources, however, is based on intrinsic bulk physical properties and extrinsic characteristics of the deposits that can be directly measured, mathematically derived from measurement, or interpreted with remote sensing and geophysical data. ?? 1995 Oxford UniversityPress.

  17. Reversible Hippocampal Lesions Disrupt Water Maze Performance during Both Recent and Remote Memory Tests

    ERIC Educational Resources Information Center

    Broadbent, Nicola J.; Squire, Larry R.; Clark, Robert E.

    2006-01-01

    Conventional lesion methods have shown that damage to the rodent hippocampus can impair previously acquired spatial memory in tasks such as the water maze. In contrast, work with reversible lesion methods using a different spatial task has found remote memory to be spared. To determine whether the finding of spared remote spatial memory depends on…

  18. Quantum teleportation between remote atomic-ensemble quantum memories.

    PubMed

    Bao, Xiao-Hui; Xu, Xiao-Fan; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei

    2012-12-11

    Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a "quantum channel," quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers [Bennett CH, et al. (1993) Phys Rev Lett 70(13):1895-1899]. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of ∼10(8) rubidium atoms and connected by a 150-m optical fiber. The spin wave state of one atomic ensemble is mapped to a propagating photon and subjected to Bell state measurements with another single photon that is entangled with the spin wave state of the other ensemble. Two-photon detection events herald the success of teleportation with an average fidelity of 88(7)%. Besides its fundamental interest as a teleportation between two remote macroscopic objects, our technique may be useful for quantum information transfer between different nodes in quantum networks and distributed quantum computing.

  19. Hippocampal neurogenesis enhancers promote forgetting of remote fear memory after hippocampal reactivation by retrieval.

    PubMed

    Ishikawa, Rie; Fukushima, Hotaka; Frankland, Paul W; Kida, Satoshi

    2016-09-26

    Forgetting of recent fear memory is promoted by treatment with memantine (MEM), which increases hippocampal neurogenesis. The approaches for treatment of post-traumatic stress disorder (PTSD) using rodent models have focused on the extinction and reconsolidation of recent, but not remote, memories. Here we show that, following prolonged re-exposure to the conditioning context, enhancers of hippocampal neurogenesis, including MEM, promote forgetting of remote contextual fear memory. However, these interventions are ineffective following shorter re-exposures. Importantly, we find that long, but not short re-exposures activate gene expression in the hippocampus and induce hippocampus-dependent reconsolidation of remote contextual fear memory. Furthermore, remote memory retrieval becomes hippocampus-dependent after the long-time recall, suggesting that remote fear memory returns to a hippocampus dependent state after the long-time recall, thereby allowing enhanced forgetting by increased hippocampal neurogenesis. Forgetting of traumatic memory may contribute to the development of PTSD treatment.

  20. Administering an epoch initiated for remote memory access

    DOEpatents

    Blocksome, Michael A; Miller, Douglas R

    2014-03-18

    Methods, systems, and products are disclosed for administering an epoch initiated for remote memory access that include: initiating, by an origin application messaging module on an origin compute node, one or more data transfers to a target compute node for the epoch; initiating, by the origin application messaging module after initiating the data transfers, a closing stage for the epoch, including rejecting any new data transfers after initiating the closing stage for the epoch; determining, by the origin application messaging module, whether the data transfers have completed; and closing, by the origin application messaging module, the epoch if the data transfers have completed.

  1. Administering an epoch initiated for remote memory access

    DOEpatents

    Blocksome, Michael A; Miller, Douglas R

    2012-10-23

    Methods, systems, and products are disclosed for administering an epoch initiated for remote memory access that include: initiating, by an origin application messaging module on an origin compute node, one or more data transfers to a target compute node for the epoch; initiating, by the origin application messaging module after initiating the data transfers, a closing stage for the epoch, including rejecting any new data transfers after initiating the closing stage for the epoch; determining, by the origin application messaging module, whether the data transfers have completed; and closing, by the origin application messaging module, the epoch if the data transfers have completed.

  2. Administering an epoch initiated for remote memory access

    DOEpatents

    Blocksome, Michael A.; Miller, Douglas R.

    2013-01-01

    Methods, systems, and products are disclosed for administering an epoch initiated for remote memory access that include: initiating, by an origin application messaging module on an origin compute node, one or more data transfers to a target compute node for the epoch; initiating, by the origin application messaging module after initiating the data transfers, a closing stage for the epoch, including rejecting any new data transfers after initiating the closing stage for the epoch; determining, by the origin application messaging module, whether the data transfers have completed; and closing, by the origin application messaging module, the epoch if the data transfers have completed.

  3. Effects of Sleep Deprivation and Aging on Long-Term and Remote Memory in Mice

    ERIC Educational Resources Information Center

    Vecsey, Christopher G.; Park, Alan J.; Khatib, Nora; Abel, Ted

    2015-01-01

    Sleep deprivation (SD) following hippocampus-dependent learning in young mice impairs memory when tested the following day. Here, we examined the effects of SD on remote memory in both young and aged mice. In young mice, we found that memory is still impaired 1 mo after training. SD also impaired memory in aged mice 1 d after training, but, by a…

  4. Flavor Dependent Retention of Remote Food Preference Memory

    PubMed Central

    Singh, Aditya; Kumar, Suraj; Singh, Vikram Pal; Das, Asish; Balaji, J.

    2017-01-01

    Social Transmission of Food Preference (STFP) is a single trial non-aversive learning task that is used for testing non-spatial memory. This task relies on an accurate estimate of a change in food preference of the animals following social demonstration of a novel flavor. Conventionally this is done by providing two flavors of powdered food and later estimating the amount of food consumed for each of these flavors in a defined period of time. This is achieved through a careful measurement of leftover food for each of these flavors. However, in mice, only a small (~1 g) amount of food is consumed making the weight estimates error prone and thereby limiting the sensitivity of the paradigm. Using multiplexed video tracking, we show that the pattern of consumption can be used as a reliable reporter of memory retention in this task. In our current study, we use this as a measure and show that the preference for the demonstrated flavor significantly increases following demonstration and the retention of this change in preference during remote testing is flavor specific. Further, we report a modified experimental design for performing STFP that allows testing of change in preference among two flavors simultaneously. Using this paradigm, we show that during remote testing for thyme and basil demonstrated flavors, only basil demonstrated mice retain the change in preference while thyme demonstrated mice do not. PMID:28210216

  5. Inactivation of the Anterior Cingulate Reveals Enhanced Reliance on Cortical Networks for Remote Spatial Memory Retrieval after Sequential Memory Processing

    PubMed Central

    Wartman, Brianne C.; Gabel, Jennifer; Holahan, Matthew R.

    2014-01-01

    One system consolidation model suggests that as time passes, ensembles of cortical neurons form strong connections to represent remote memories. In this model, the anterior cingulate cortex (ACC) serves as a cortical region that represents remote memories. However, there is debate as to whether remote spatial memories go through this systems consolidation process and come to rely on the ACC. The present experiment examined whether increasing the processing demand on the hippocampus, by sequential training on two spatial tasks, would more fully engage the ACC during retrieval of a remote spatial memory. In this scenario, inactivation of the ACC at a remote time point was hypothesized to produce a severe memory deficit if rats had been trained on two, sequential spatial tasks. Rats were trained on a water maze (WM) task only or a WM task followed by a radial arm maze task. A WM probe test was given recently or remotely to all rats. Prior to the probe test, rats received an injection of saline or muscimol into the ACC. A subtle deficit in probe performance was found at the remote time point in the group trained on only one spatial task and treated with muscimol. In the group trained on two spatial tasks and treated with muscimol, a subtle deficit in probe performance was noted at the recent time point and a substantial deficit in probe performance was observed at the remote time point. c-Fos labeling in the hippocampus revealed more labeling in the CA1 region in all remotely tested groups than recently tested groups. Findings suggest that spatial remote memories come to rely more fully on the ACC when hippocampal processing requirements are increased. Results also suggest continued involvement of the hippocampus in spatial memory retrieval along with a progressive strengthening of cortical connections as time progresses. PMID:25279556

  6. Effects of sleep deprivation and aging on long-term and remote memory in mice

    PubMed Central

    Vecsey, Christopher G.; Park, Alan J.; Khatib, Nora

    2015-01-01

    Sleep deprivation (SD) following hippocampus-dependent learning in young mice impairs memory when tested the following day. Here, we examined the effects of SD on remote memory in both young and aged mice. In young mice, we found that memory is still impaired 1 mo after training. SD also impaired memory in aged mice 1 d after training, but, by a month after training, sleep-deprived and control aged animals performed similarly, primarily due to remote memory decay in the control aged animals. Gene expression analysis supported the finding that SD has similar effects on the hippocampus in young and aged mice. PMID:25776037

  7. Ferromagnetic shape memory flapper for remotely actuated propulsion systems

    NASA Astrophysics Data System (ADS)

    Kanner, Oren Y.; Shilo, Doron; Sheng, Jian; James, Richard D.; Ganor, Yaniv

    2013-08-01

    Generating propulsion with small-scale devices is a major challenge due to both the domination of viscous forces at low Reynolds numbers as well as the small relative stroke length of traditional actuators. Ferromagnetic shape memory materials are good candidates for such devices as they exhibit a unique combination of large strains and fast responses, and can be remotely activated by magnetic fields. This paper presents the design, analysis, and realization of a novel NiMnGa shear actuation method, which is especially suitable for small-scale fluid propulsion. A fluid mechanics analysis shows that the two key parameters for powerful propulsion are the engineering shear strain and twin boundary velocity. Using high-speed photography, we directly measure both parameters under an alternating magnetic field. Reynolds numbers in the inertial flow regime (>700) are evaluated. Measurements of the transient thrust show values up to 40 mN, significantly higher than biological equivalents. This work paves the way for new remotely activated and controlled propulsion for untethered micro-scale robots.

  8. Remote sensing and airborne geophysics in the assessment of natural aggregate resources

    USGS Publications Warehouse

    Knepper, D.H.; Langer, W.H.; Miller, S.H.

    1994-01-01

    Natural aggregate made from crushed stone and deposits of sand and gravel is a vital element of the construction industry in the United States. Although natural aggregate is a high volume/low value commodity that is relatively abundant, new sources of aggregate are becoming increasingly difficult to find and develop because of rigid industry specifications, political considerations, development and transporation costs, and environmental concerns, especially in urban growth centers where much of the aggregate is used. As the demand for natural aggregate increases in response to urban growth and the repair and expansion of the national infrastructure, new sources of natural aggregate will be required. The USGS has recognized the necessity of developing the capability to assess the potential for natural aggregate sources on Federal lands; at present, no methodology exists for systematically describing and evaluating potential sources of natural aggregate. Because remote sensing and airborne geophysics can detect surface and nearsurface phenomena, these tools may useful for detecting and mapping potential sources of natural aggregate; however, before a methodology for applying these tools can be developed, it is necessary to understand the type, distribution, physical properties, and characteristics of natural aggregate deposits, as well as the problems that will be encountered in assessing their potential value. There are two primary sources of natural aggregate: (1) exposed or near-surface igneous, metamorphic, and sedimentary bedrock that can be crushed, and (2) deposits of sand and gravel that may be used directly or crushed and sized to meet specifications. In any particular area, the availability of bedrock suitable for crushing is a function of the geologic history of the area - the processes that formed, deformed, eroded and exposed the bedrock. Deposits of sand and gravel are primarily surficial deposits formed by the erosion, transportation by water and ice

  9. Simulation of the optical properties of plate aggregates for application to the remote sensing of cirrus clouds.

    PubMed

    Xie, Yu; Yang, Ping; Kattawar, George W; Baum, Bryan A; Hu, Yongxiang

    2011-03-10

    In regions of deep tropical convection, ice particles often undergo aggregation and form complex chains. To investigate the effect of the representation of aggregates on electromagnetic scattering calculations, we developed an algorithm to efficiently specify the geometries of aggregates and to compute some of their geometric parameters, such as the projected area. Based on in situ observations, ice aggregates are defined as clusters of hexagonal plates with a chainlike overall shape, which may have smooth or roughened surfaces. An aggregate representation is developed with 10 ensemble members, each consisting of between 4-12 hexagonal plates. The scattering properties of an individual aggregate ice particle are computed using either the discrete dipole approximation or an improved geometric optics method, depending upon the size parameters. Subsequently, the aggregate properties are averaged over all geometries. The scattering properties of the aggregate representation closely agree with those computed from 1000 different aggregate geometries. As a result, the aggregate representation provides an accurate and computationally efficient way to represent all aggregates occurring within ice clouds. Furthermore, the aggregate representation can be used to study the influence of these complex ice particles on the satellite-based remote sensing of ice clouds. The computed cloud reflectances for aggregates are different from those associated with randomly oriented individual hexagonal plates. When aggregates are neglected, simulated cloud reflectances are generally lower at visible and shortwave-infrared wavelengths, resulting in smaller effective particle sizes but larger optical thicknesses.

  10. A Map-Reduce-enabled SOLAP cube for large-scale remotely sensed data aggregation

    NASA Astrophysics Data System (ADS)

    Li, Jiyuan; Meng, Lingkui; Wang, Frank Z.; Zhang, Wen; Cai, Yang

    2014-09-01

    Spatial On-Line Analytical Processing (SOLAP) is a powerful decision support systems tool for exploring the multidimensional perspective of spatial data. In recent years, remotely sensed data have been integrated into SOLAP cubes, and this improvement has advantages in spatio-temporal analysis for environment monitoring. However, the performance of aggregations in SOLAP still faces a considerable challenge from the large-scale dataset generated by Earth observation. From the perspective of data parallelism, a tile-based SOLAP cube model, the so-called Tile Cube, is presented in this paper. The novel model implements Roll-Up/Drill-Across operations in the SOLAP environment based on Map-Reduce, a popular data-intensive computing paradigm, and improves the throughput and scalability of raster aggregation. Therefore, the long time-series, wide-range and multi-view analysis of remotely sensed data can be processed in a short time. The Tile Cube prototype was built on Hadoop/Hbase, and drought monitoring is used as an example to illustrate the aggregations in the model. The performance testing indicated the model can be scaled along with both the data growth and node growth. It is applicable and natural to integrate the SOLAP cube with Map-Reduce. Factors that influence the performance are also discussed, and the balance of them will be considered in future works to make full use of data locality for model optimisation.

  11. Optimizing NEURON Simulation Environment Using Remote Memory Access with Recursive Doubling on Distributed Memory Systems.

    PubMed

    Shehzad, Danish; Bozkuş, Zeki

    2016-01-01

    Increase in complexity of neuronal network models escalated the efforts to make NEURON simulation environment efficient. The computational neuroscientists divided the equations into subnets amongst multiple processors for achieving better hardware performance. On parallel machines for neuronal networks, interprocessor spikes exchange consumes large section of overall simulation time. In NEURON for communication between processors Message Passing Interface (MPI) is used. MPI_Allgather collective is exercised for spikes exchange after each interval across distributed memory systems. The increase in number of processors though results in achieving concurrency and better performance but it inversely affects MPI_Allgather which increases communication time between processors. This necessitates improving communication methodology to decrease the spikes exchange time over distributed memory systems. This work has improved MPI_Allgather method using Remote Memory Access (RMA) by moving two-sided communication to one-sided communication, and use of recursive doubling mechanism facilitates achieving efficient communication between the processors in precise steps. This approach enhanced communication concurrency and has improved overall runtime making NEURON more efficient for simulation of large neuronal network models.

  12. Optimizing NEURON Simulation Environment Using Remote Memory Access with Recursive Doubling on Distributed Memory Systems

    PubMed Central

    Bozkuş, Zeki

    2016-01-01

    Increase in complexity of neuronal network models escalated the efforts to make NEURON simulation environment efficient. The computational neuroscientists divided the equations into subnets amongst multiple processors for achieving better hardware performance. On parallel machines for neuronal networks, interprocessor spikes exchange consumes large section of overall simulation time. In NEURON for communication between processors Message Passing Interface (MPI) is used. MPI_Allgather collective is exercised for spikes exchange after each interval across distributed memory systems. The increase in number of processors though results in achieving concurrency and better performance but it inversely affects MPI_Allgather which increases communication time between processors. This necessitates improving communication methodology to decrease the spikes exchange time over distributed memory systems. This work has improved MPI_Allgather method using Remote Memory Access (RMA) by moving two-sided communication to one-sided communication, and use of recursive doubling mechanism facilitates achieving efficient communication between the processors in precise steps. This approach enhanced communication concurrency and has improved overall runtime making NEURON more efficient for simulation of large neuronal network models. PMID:27413363

  13. Chiral memory via chiral amplification and selective depolymerization of porphyrin aggregates.

    PubMed

    Helmich, Floris; Lee, Cameron C; Schenning, Albertus P H J; Meijer, E W

    2010-12-01

    Chiral memory at the supramolecular level is obtained via a new approach using chiral Zn porphrins and achiral Cu porphyrins. In a "sergeant-and-soldiers" experiment, the Zn "sergeant" transfers its own chirality to Cu "soldiers" and, after chiral amplification, the "sergeant" is removed from the coaggregates by axial ligation with a Lewis base. After this extraction, the preferred helicity observed for the aggregates containing achiral Cu porphyrins reveals a chiral memory effect that is stable and can be erased and partially restored upon subsequent heating and cooling.

  14. Mapping Surface Cover Parameters Using Aggregation Rules and Remotely Sensed Cover Classes. Version 1.9

    NASA Technical Reports Server (NTRS)

    Arain, Altaf M.; Shuttleworth, W. James; Yang, Z-Liang; Michaud, Jene; Dolman, Johannes

    1997-01-01

    A coupled model, which combines the Biosphere-Atmosphere Transfer Scheme (BATS) with an advanced atmospheric boundary-layer model, was used to validate hypothetical aggregation rules for BATS-specific surface cover parameters. The model was initialized and tested with observations from the Anglo-Brazilian Amazonian Climate Observational Study and used to simulate surface fluxes for rain forest and pasture mixes at a site near Manaus in Brazil. The aggregation rules are shown to estimate parameters which give area-average surface fluxes similar to those calculated with explicit representation of forest and pasture patches for a range of meteorological and surface conditions relevant to this site, but the agreement deteriorates somewhat when there are large patch-to-patch differences in soil moisture. The aggregation rules, validated as above, were then applied to remotely sensed 1 km land cover data set to obtain grid-average values of BATS vegetation parameters for 2.8 deg x 2.8 deg and 1 deg x 1 deg grids within the conterminous United States. There are significant differences in key vegetation parameters (aerodynamic roughness length, albedo, leaf area index, and stomatal resistance) when aggregate parameters are compared to parameters for the single, dominant cover within the grid. However, the surface energy fluxes calculated by stand-alone BATS with the 2-year forcing, data from the International Satellite Land Surface Climatology Project (ISLSCP) CDROM were reasonably similar using aggregate-vegetation parameters and dominant-cover parameters, but there were some significant differences, particularly in the western USA.

  15. Symmetric Data Objects and Remote Memory Access Communication for Fortran 95-Applications.

    SciTech Connect

    Nieplocha, Jarek; Baxter, Douglas J.; Tipparaju, Vinod; Rasmussen, Craig; Numrich, Robert W.

    2005-08-01

    Symmetric data objects have been introduced by Cray Inc. in context of SHMEM remote memory access communication on Cray T3D/E systems and later adopted by SGI for their Origin servers. Symmetric data objects greatly simplify parallel programming by allowing to reference remote instance of a data structure by specifying address of the local counterpart. The current paper describes how symmetric data objects and remote memory access communication could be implemented in Fortran-95 without requiring specialized hardware or compiler support. NAS Multi-Grid parallel benchmark was used as an application example and demonstrated competitive performance to the standard MPI implementation

  16. Recent and remote spatial memory in mice treated with cytosine arabinoside.

    PubMed

    Fremouw, Thane; Fessler, Christy L; Ferguson, Robert J; Burguete, Yamil

    2012-01-01

    Clinical studies suggest that chemotherapy is associated with long-term cognitive impairment in some patients. A number of underlying mechanisms have been proposed, however, the etiology of chemotherapy-related cognitive dysfunction remains relatively unknown. As part of a multifaceted approach, animal models of chemotherapy-induced cognitive impairment are being developed. Thus far, the majority of animal studies have utilized a rat model, however, mice may prove particularly beneficial in studying genetic risk factors for developing chemotherapy-induced cognitive impairment. Various chemotherapy agents, including cytosine arabinoside (Ara-C), have been found to impair remote spatial memory in rats in the Morris water maze. The present study evaluated the effects of Ara-C on remote (30 d) spatial memory in mice. In addition, the possibility that time relative to chemotherapy treatment may modulate the effect of chemotherapy on spatial learning and/or recent (1 d) memory was explored. Male C57BL/6J mice received either Ara-C (275 mg/kg i.p. daily for 5 days) or saline. Spatial learning and memory was assessed using the Morris water maze. Half the mice performed a remote (30 d) memory version of the task and the other half performed a recent (1 d) memory version of the task. The experiment was designed such that the probe trial for the recent memory version occurred on the same day relative to chemotherapy treatment as the remote memory version. Despite significant toxic effects as assessed by weight loss, Ara-C treated mice performed as well as control mice during acquisition, recent memory, and remote memory portions of the task. As are some humans, C57BL/6J mice may be resistant to at least some aspects of chemotherapy induced cognitive decline.

  17. M1 muscarinic receptors are necessary for retrieval of remote context fear memory.

    PubMed

    Patricio, Rafael Rodisanski; Soares, Juliana Carlota Kramer; Oliveira, Maria Gabriela Menezes

    2017-02-01

    Several studies have investigated the transition of consolidation of recent memory to remote memory in aversively motivated tasks, such as contextual fear conditioning (CFC) and inhibitory avoidance (IA). However, the mechanisms that serve the retrieval of remote memories, has not yet been fully understood. Some evidences suggest that the central cholinergic system appears be involved in the modulation of these processes. Therefore, the present study aimed to investigate the effects of a pre-test administration of dicyclomine, a high-affinity M1 muscarinic receptor antagonist, on the retrieval of remote memories in fear conditioning and IA tasks. Male Wistar rats were trained, and after 1 or 28days, the rats received dicyclomine (16 or 32mg/kg, intraperitoneally, i.p.) and were tested in CFC, tone fear conditioning (TFC) and IA tasks. At both time intervals, 32mg/kg dicyclomine induced impairment of CFC. In TFC task only the performance of the rats 28days after training was impaired. The IA task was not affected in any of the studied intervals. These findings suggest a differential contribution of muscarinic receptors on recent and remote memories retrieval revealing a more generalized role in remote memory.

  18. Remote spectral identification of surface aggregates by thermal imaging techniques - Progress report

    NASA Technical Reports Server (NTRS)

    Scholen, Douglas E.; Clerke, William H.; Burns, Gregory S.

    1991-01-01

    The NASA Thermal Infrared Multispectral Scanner (TIMS) has been successfully used for the remote identification of a variety of soil and aggregate deposits in vegetated areas of two states. Over three million cubic meters of gravel deposits were identified from the imagery during a two year period. Verification was accomplished by ground reconnaissance using drilling machinery and by ground instrumentation. The method has been used to differentiate between fine and coarse grained soils, and gravel deposits. The deposits were found to have been naturally sorted according to grain size by depositional processes, providing each deposit with distinct spectral qualities. It was found that the masking effects of relatively dense vegetation were largely overcome by using imagery acquired at higher altitudes above terrain than 9000 meters, due to loss of resolution of the finer detail. The mechanics of image resolution are discussed, a method of data analysis used is described, and sample spectral signatures are illustrated.

  19. Remote Memory Access Protocol Target Node Intellectual Property

    NASA Technical Reports Server (NTRS)

    Haddad, Omar

    2013-01-01

    The MagnetoSpheric Multiscale (MMS) mission had a requirement to use the Remote Memory Access Protocol (RMAP) over its SpaceWire network. At the time, no known intellectual property (IP) cores were available for purchase. Additionally, MMS preferred to implement the RMAP functionality with control over the low-level details of the design. For example, not all the RMAP standard functionality was needed, and it was desired to implement only the portions of the RMAP protocol that were needed. RMAP functionality had been previously implemented in commercial off-the-shelf (COTS) products, but the IP core was not available for purchase. The RMAP Target IP core is a VHDL (VHSIC Hardware Description Language description of a digital logic design suitable for implementation in an FPGA (field-programmable gate array) or ASIC (application-specific integrated circuit) that parses SpaceWire packets that conform to the RMAP standard. The RMAP packet protocol allows a network host to access and control a target device using address mapping. This capability allows SpaceWire devices to be managed in a standardized way that simplifies the hardware design of the device, as well as the development of the software that controls the device. The RMAP Target IP core has some features that are unique and not specified in the RMAP standard. One such feature is the ability to automatically abort transactions if the back-end logic does not respond to read/write requests within a predefined time. When a request times out, the RMAP Target IP core automatically retracts the request and returns a command response with an appropriate status in the response packet s header. Another such feature is the ability to control the SpaceWire node or router using RMAP transactions in the extended address range. This allows the SpaceWire network host to manage the SpaceWire network elements using RMAP packets, which reduces the number of protocols that the network host needs to support.

  20. Dissociation of the Role of Infralimbic Cortex in Learning and Consolidation of Extinction of Recent and Remote Aversion Memory.

    PubMed

    Awad, Walaa; Ferreira, Guillaume; Maroun, Mouna

    2015-10-01

    Medial prefrontal circuits have been reported to undergo a major reorganization over time and gradually take a more important role for remote emotional memories such as contextual fear memory or food aversion memory. The medial prefrontal cortex, and specifically its ventral subregion, the infralimbic cortex (IL), was also reported to be critical for recent memory extinction of contextual fear conditioning and conditioned odor aversion. However, its exact role in the extinction of remotely acquired information is still not clear. Using postretrieval blockade of protein synthesis or inactivation of the IL, we showed that the IL is similarly required for extinction consolidation of recent and remote fear memory. However, in odor aversion memory, the IL was only involved in extinction consolidation of recent, but not remote, memory. In contrast, only remote retrieval of aversion memory induced c-Fos activation in the IL and preretrieval inactivation of the IL with lidocaine impaired subsequent extinction of remote but not recent memory, indicating IL is necessary for extinction learning of remote aversion memory. In contrast to the effects in odor aversion, our data show that the involvement of the IL in the consolidation of fear extinction does not depend on the memory age. More importantly, our data indicate that the IL is implicated in the extinction of fear and nonfear-based associations and suggest dissociation in the engagement of the IL in the learning and consolidation of food aversion extinction over time.

  1. Recent versus remote: flashbulb memory for 9/11 and self-selected events from the reminiscence bump.

    PubMed

    Denver, Jenny Y; Lane, Sean M; Cherry, Katie E

    2010-01-01

    In two related studies, we examined flashbulb memories acquired from different points in the lifespan in younger and older adults. When asked to remember flashbulb memories from their lives, older adults were most likely to recall events from the reminiscence bump (Study 1A). In Study 1B, younger and older adults recalled 9/11 and a personal flashbulb event that occurred between ages 10 and 30. Older adults' memories of a recent event (9/11) were less likely than younger adults' to be classified as flashbulb memories; however, when memories were examined in their entirety, these age-related declines disappeared. Older adults' memories for a remote flashbulb event appeared to be quite similar, if not more detailed than their memories for the recent event, suggesting that remote flashbulb memories are relatively stable over time. Implications of these data for current views of flashbulb memory in late adulthood are discussed.

  2. Towards scalable parellelism in Monte Carlo particle transport codes using remote memory access

    SciTech Connect

    Romano, Paul K; Brown, Forrest B; Forget, Benoit

    2010-01-01

    One forthcoming challenge in the area of high-performance computing is having the ability to run large-scale problems while coping with less memory per compute node. In this work, they investigate a novel data decomposition method that would allow Monte Carlo transport calculations to be performed on systems with limited memory per compute node. In this method, each compute node remotely retrieves a small set of geometry and cross-section data as needed and remotely accumulates local tallies when crossing the boundary of the local spatial domain. initial results demonstrate that while the method does allow large problems to be run in a memory-limited environment, achieving scalability may be difficult due to inefficiencies in the current implementation of RMA operations.

  3. Efficient teleportation between remote single-atom quantum memories.

    PubMed

    Nölleke, Christian; Neuzner, Andreas; Reiserer, Andreas; Hahn, Carolin; Rempe, Gerhard; Ritter, Stephan

    2013-04-05

    We demonstrate teleportation of quantum bits between two single atoms in distant laboratories. Using a time-resolved photonic Bell-state measurement, we achieve a teleportation fidelity of (88.0 ± 1.5)%, largely determined by our entanglement fidelity. The low photon collection efficiency in free space is overcome by trapping each atom in an optical cavity. The resulting success probability of 0.1% is almost 5 orders of magnitude larger than in previous experiments with remote material qubits. It is mainly limited by photon propagation and detection losses and can be enhanced with a cavity-based deterministic Bell-state measurement.

  4. Arc/Arg3.1 mRNA Global Expression Patterns Elicited by Memory Recall in Cerebral Cortex Differ for Remote Versus Recent Spatial Memories

    PubMed Central

    Gusev, Pavel A.; Gubin, Alexander N.

    2010-01-01

    The neocortex plays a critical role in the gradual formation and storage of remote declarative memories. Because the circuitry mechanisms of systems-level consolidation are not well understood, the precise cortical sites for memory storage and the nature of enduring memory correlates (mnemonic plasticity) are largely unknown. Detailed maps of neuronal activity underlying recent and remote memory recall highlight brain regions that participate in systems consolidation and constitute putative storage sites, and thus may facilitate detection of mnemonic plasticity. To localize cortical regions involved in the recall of a spatial memory task, we trained rats in a water-maze and then mapped mRNA expression patterns of a neuronal activity marker Arc/Arg3.1 (Arc) upon recall of recent (24 h after training) or remote (1 month after training) memories and compared them with swimming and naive controls. Arc gene expression was significantly more robust 24 h after training compared to 1 month after training. Arc expression diminished in the parietal, cingulate and visual areas, but select segments in the prefrontal, retrosplenial, somatosensory and motor cortical showed similar robust increases in the Arc expression. When Arc expression was compared across select segments of sensory, motor and associative regions within recent and remote memory groups, the overall magnitude and cortical laminar patterns of task-specific Arc expression were similar (stereotypical). Arc mRNA fractions expressed in the upper cortical layers (2/3, 4) increased after both recent and remote recall, while layer 6 fractions decreased only after the recent recall. The data suggest that robust recall of remote memory requires an overall smaller increase in neuronal activity within fewer cortical segments. This activity trend highlights the difficulty in detecting the storage sites and plasticity underlying remote memory. Application of the Arc maps may ameliorate this difficulty. PMID:20577636

  5. Inhibition of Adult Neurogenesis by Inducible and Targeted Deletion of ERK5 MAP Kinase Specifically in Adult Neurogenic Regions Impairs Contextual Fear Memory Extinction and Remote Fear Memory

    PubMed Central

    Pan, Yung-Wei; Chan, Guy C.K.; Kuo, Chay T.; Storm, Daniel R.; Xia, Zhengui

    2012-01-01

    Although there is evidence suggesting that adult neurogenesis may contribute to hippocampus-dependent memory, signaling mechanisms responsible for adult hippocampal neurogenesis are not well characterized. Here we report that ERK5 MAP kinase is specifically expressed in the neurogenic regions of the adult mouse brain. The inducible and conditional knockout (icKO) of erk5 specifically in neural progenitors of the adult mouse brain attenuated adult hippocampal neurogenesis. It also caused deficits in several forms of hippocampus-dependent memory including contextual fear conditioning generated by a weak foot shock. The ERK5 icKO mice were also deficient in extinction of contextual fear memory and reversal of Morris water maze spatial learning and memory, suggesting that adult neurogenesis is important for learning that requires active forgetting of a prior memory. Furthermore, our data suggest a critical role for ERK5-mediated adult neurogenesis in pattern separation, a form of dentate gyrus-dependent spatial learning and memory. Moreover, ERK5 icKO mice have no memory 21 days post-training in the passive avoidance test, suggesting a pivotal role for adult hippocampal neurogenesis in the expression of remote memory. Together, our results implicate ERK5 as a novel signaling molecule regulating adult neurogenesis and provide strong evidence that adult neurogenesis is critical for several forms of hippocampus-dependent memory formation including memory extinction, and for the expression of remote memory. PMID:22573667

  6. Involvement of the Anterior Cingulate Cortex in Formation, Consolidation, and Reconsolidation of Recent and Remote Contextual Fear Memory

    ERIC Educational Resources Information Center

    Einarsson, Einar O.; Nader, Karim

    2012-01-01

    It has been suggested that memories become more stable and less susceptible to the disruption of reconsolidation over weeks after learning. Here, we test this by targeting the anterior cingulate cortex (ACC) and test its involvement in the formation, consolidation, and reconsolidation of recent and remote contextual fear memory. We found that…

  7. Extinction after retrieval: effects on the associative and nonassociative components of remote contextual fear memory.

    PubMed

    Costanzi, Marco; Cannas, Sara; Saraulli, Daniele; Rossi-Arnaud, Clelia; Cestari, Vincenzo

    2011-01-01

    Long-lasting memories of adverse experiences are essential for individuals' survival but are also involved, in the form of recurrent recollections of the traumatic experience, in the aetiology of anxiety diseases (e.g., post-traumatic stress disorder [PTSD]). Extinction-based erasure of fear memories has long been pursued as a behavioral way to treat anxiety disorders; yet, such a procedure turns out to be transient, context-dependent, and ineffective unless it is applied immediately after trauma. Recent evidence indicates that, in both rats and humans, extinction training can prevent the return of fear if administered within the reconsolidation window, when memories become temporarily labile and susceptible of being updated. Here, we show that the reconsolidation-extinction procedure fails to prevent the spontaneous recovery of a remote contextual fear memory in a mouse model of PTSD, as well as the long-lasting behavioral abnormalities induced by traumatic experience on anxiety and in both social and cognitive domains (i.e., social withdrawal and spatial learning deficits). Such a failure appears to be related to the ineffectiveness of the reconsolidation-extinction procedure in targeting the pathogenic process of fear sensitization, a nonassociative component of traumatic memory that causes animals to react aberrantly to harmless stimuli. This indicates fear sensitization as a major target for treatments aimed at mitigating anxiety and the behavioral outcomes of traumatic experiences.

  8. Prenatal Stress Produces Persistence of Remote Memory and Disrupts Functional Connectivity in the Hippocampal-Prefrontal Cortex Axis.

    PubMed

    Negrón-Oyarzo, Ignacio; Neira, David; Espinosa, Nelson; Fuentealba, Pablo; Aboitiz, Francisco

    2015-09-01

    Prenatal stress is a risk factor for the development of neuropsychiatric disorders, many of which are commonly characterized by an increased persistence of aversive remote memory. Here, we addressed the effect of prenatal stress on both memory consolidation and functional connectivity in the hippocampal-prefrontal cortex axis, a dynamical interplay that is critical for mnemonic processing. Pregnant mice of the C57BL6 strain were subjected to restraint stressed during the last week of pregnancy, and male offspring were behaviorally tested at adulthood for recent and remote spatial memory performance in the Barnes Maze test under an aversive context. Prenatal stress did not affect the acquisition or recall of recent memory. In contrast, it produced the persistence of remote spatial memory. Memory persistence was not associated with alterations in major network rhythms, such as hippocampal sharp-wave ripples (SWRs) or neocortical spindles. Instead, it was associated with a large decrease in the basal discharge activity of identified principal neurons in the medial prefrontal cortex (mPFC) as measured in urethane anesthetized mice. Furthermore, functional connectivity was disrupted, as the temporal coupling between neuronal discharge in the mPFC and hippocampal SWRs was decreased by prenatal stress. These results could be relevant to understand the biological basis of the persistence of aversive remote memories in stress-related disorders.

  9. dRHP-PseRA: detecting remote homology proteins using profile-based pseudo protein sequence and rank aggregation

    PubMed Central

    Chen, Junjie; Long, Ren; Wang, Xiao-long; Liu, Bin; Chou, Kuo-Chen

    2016-01-01

    Protein remote homology detection is an important task in computational proteomics. Some computational methods have been proposed, which detect remote homology proteins based on different features and algorithms. As noted in previous studies, their predictive results are complementary to each other. Therefore, it is intriguing to explore whether these methods can be combined into one package so as to further enhance the performance power and application convenience. In view of this, we introduced a protein representation called profile-based pseudo protein sequence to extract the evolutionary information from the relevant profiles. Based on the concept of pseudo proteins, a new predictor, called “dRHP-PseRA”, was developed by combining four state-of-the-art predictors (PSI-BLAST, HHblits, Hmmer, and Coma) via the rank aggregation approach. Cross-validation tests on a SCOP benchmark dataset have demonstrated that the new predictor has remarkably outperformed any of the existing methods for the same purpose on ROC50 scores. Accordingly, it is anticipated that dRHP-PseRA holds very high potential to become a useful high throughput tool for detecting remote homology proteins. For the convenience of most experimental scientists, a web-server for dRHP-PseRA has been established at http://bioinformatics.hitsz.edu.cn/dRHP-PseRA/. PMID:27581095

  10. Remote spatial memory and the hippocampus: effect of early and extensive training in the radial maze.

    PubMed

    Ramos, Juan M J

    2009-09-01

    In a previous study we showed a temporally graded retrograde amnesia after hippocampal lesions when rats learned a spatial reference memory task in which two types of signals simultaneously indicated the goal arm (shape of the experimental room and extramaze landmarks). To investigate the effect that the navigational demands of the task have on remote memory expression, the same task was used in the present study as in our previous report, but on this occasion the shape of the surroundings was not predictive, which resulted in a highly demanding spatial task. Additionally, animals received extensive training in an early phase to ensure that the task was well learned. Results indicated a profound retrograde amnesia when dorsal hippocampal lesions were made 1 or 70 d after the end of the training (experiments 1 and 2). Using a long period of retraining, however, lesioned animals in the 70-d groups showed progressively more spared memory than the lesioned rats of the 1-d group. Experiments 3 and 4 showed that rats did not learn the above spatial task through an S-R association. Specifically, when animals acquired the task using a single cue (intra- or extramaze), hippocampal lesions did not produce retrograde amnesia. These findings support the possibility that in a highly demanding spatial task, hippocampal lesions produce a performance/navigational impairment that could interfere with the expression of spared remote spatial memory. The long period of retraining, however, seems to partially compensate for this deficit, but only when a long learning-surgery interval is employed.

  11. Aggregation and Disaggregation Techniques Applied on Remotely Sensed Data to Obtain Optimum Resolution for Surface Energy Fluxes Estimation

    NASA Astrophysics Data System (ADS)

    Agam, N.; Kustas, W. P.; Li, F.; Anderson, M. C.

    2006-05-01

    Continuous monitoring of surface energy fluxes provides an important tool for precision agriculture management. It is, therefore, desirable to obtain these fluxes at agricultural field size (length scale ~ 10-100 m). To date, land surface temperature (LST), a fundamental input required for flux computations, is usually available at a nominal resolution of 1 km, which disables field-scale monitoring. Disaggregating LST data into field-scale sub-pixels was found to be possible, with deterioration in temperature accuracy as sub-pixel size is reduced. In contrast to LST, land use and fractional vegetation cover (LU and FC, additional key inputs) are available at high spatial resolution (e.g., 30 m). Aggregation of LU and FC to meet the lower resolution LST data introduces errors when aggregating to larger pixel sizes. The objective of this research is to find the optimum resolution that will minimize the errors due to aggregation of LU/FC and disaggregation of LST data, to provide continuous estimates of field scale surface energy fluxes. Data were used from the 2002 Soil Moisture-Atmosphere Coupling Experiment (SMACEX02) conducted over the upper Midwest corn and soybean production region of Iowa. Three dates during the period of rapid crops growth (June 23, July 1, and July 8) for which Landsat TM images are available were analyzed. The original pixels were aggregated to form 960 m pixels (to mimic thermal data currently available from MODIS) and were then disaggregated following the procedure suggested by Kustas et al. (2003)* to form 60, 120, and 240 m sub-pixels. LU and FC were obtained at 30 m resolution and then aggregated to 60, 120, 240, and 960 m. The Two-Source-Model was run at each of the resolutions using the pertinent inputs. The model output at 60 m resolution, using the original LST data was considered the base line, to which all other outputs were compared. For comparing the flux results at the lower resolutions, the 60 m flux output was aggregated. The

  12. Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory

    PubMed Central

    Moscovitch, Morris; Rosenbaum, R Shayna; Gilboa, Asaf; Addis, Donna Rose; Westmacott, Robyn; Grady, Cheryl; McAndrews, Mary Pat; Levine, Brian; Black, Sandra; Winocur, Gordon; Nadel, Lynn

    2005-01-01

    We review lesion and neuroimaging evidence on the role of the hippocampus, and other structures, in retention and retrieval of recent and remote memories. We examine episodic, semantic and spatial memory, and show that important distinctions exist among different types of these memories and the structures that mediate them. We argue that retention and retrieval of detailed, vivid autobiographical memories depend on the hippocampal system no matter how long ago they were acquired. Semantic memories, on the other hand, benefit from hippocampal contribution for some time before they can be retrieved independently of the hippocampus. Even semantic memories, however, can have episodic elements associated with them that continue to depend on the hippocampus. Likewise, we distinguish between experientially detailed spatial memories (akin to episodic memory) and more schematic memories (akin to semantic memory) that are sufficient for navigation but not for re-experiencing the environment in which they were acquired. Like their episodic and semantic counterparts, the former type of spatial memory is dependent on the hippocampus no matter how long ago it was acquired, whereas the latter can survive independently of the hippocampus and is represented in extra-hippocampal structures. In short, the evidence reviewed suggests strongly that the function of the hippocampus (and possibly that of related limbic structures) is to help encode, retain, and retrieve experiences, no matter how long ago the events comprising the experience occurred, and no matter whether the memories are episodic or spatial. We conclude that the evidence favours a multiple trace theory (MTT) of memory over two other models: (1) traditional consolidation models which posit that the hippocampus is a time-limited memory structure for all forms of memory; and (2) versions of cognitive map theory which posit that the hippocampus is needed for representing all forms of allocentric space in memory. PMID

  13. Spawning aggregation behavior and reproductive ecology of the giant bumphead parrotfish, Bolbometopon muricatum, in a remote marine reserve.

    PubMed

    Muñoz, Roldan C; Zgliczynski, Brian J; Teer, Bradford Z; Laughlin, Joseph L

    2014-01-01

    The giant bumphead parrotfish (Bolbometopon muricatum) has experienced precipitous population declines throughout its range due to its importance as a highly-prized fishery target and cultural resource. Because of its diet, Bolbometopon may serve as a keystone species on Indo-Pacific coral reefs, yet comprehensive descriptions of its reproductive ecology do not exist. We used a variety of underwater visual census (UVC) methods to study an intact population of Bolbometopon at Wake Atoll, a remote and protected coral atoll in the west Pacific. Key observations include spawning activities in the morning around the full and last quarter moon, with possible spawning extending to the new moon. We observed peaks in aggregation size just prior to and following the full and last quarter moon, respectively, and observed a distinct break in spawning at the site that persisted for four days; individuals returned to the aggregation site one day prior to the last quarter moon and resumed spawning the following day. The mating system was lek-based, characterized by early male arrival at the spawning site followed by vigorous defense (including head-butting between large males) of small territories. These territories were apparently used to attract females that arrived later in large schools, causing substantial changes in the sex ratio on the aggregation site at any given time during the morning spawning period. Aggression between males and courtship of females led to pair spawning within the upper water column. Mating interference was not witnessed but we noted instances suggesting that sperm competition might occur. Densities of Bolbometopon on the aggregation site averaged 10.07(±3.24 SE) fish per hectare (ha) with maximum densities of 51.5 fish per ha. By comparing our observations to the results of biennial surveys conducted by the National Oceanic and Atmospheric Administration (NOAA) Coral Reef Ecosystem Division (CRED), we confirmed spatial consistency of the aggregation

  14. Spawning aggregation behavior and reproductive ecology of the giant bumphead parrotfish, Bolbometopon muricatum, in a remote marine reserve

    PubMed Central

    Zgliczynski, Brian J.; Teer, Bradford Z.; Laughlin, Joseph L.

    2014-01-01

    The giant bumphead parrotfish (Bolbometopon muricatum) has experienced precipitous population declines throughout its range due to its importance as a highly-prized fishery target and cultural resource. Because of its diet, Bolbometopon may serve as a keystone species on Indo-Pacific coral reefs, yet comprehensive descriptions of its reproductive ecology do not exist. We used a variety of underwater visual census (UVC) methods to study an intact population of Bolbometopon at Wake Atoll, a remote and protected coral atoll in the west Pacific. Key observations include spawning activities in the morning around the full and last quarter moon, with possible spawning extending to the new moon. We observed peaks in aggregation size just prior to and following the full and last quarter moon, respectively, and observed a distinct break in spawning at the site that persisted for four days; individuals returned to the aggregation site one day prior to the last quarter moon and resumed spawning the following day. The mating system was lek-based, characterized by early male arrival at the spawning site followed by vigorous defense (including head-butting between large males) of small territories. These territories were apparently used to attract females that arrived later in large schools, causing substantial changes in the sex ratio on the aggregation site at any given time during the morning spawning period. Aggression between males and courtship of females led to pair spawning within the upper water column. Mating interference was not witnessed but we noted instances suggesting that sperm competition might occur. Densities of Bolbometopon on the aggregation site averaged 10.07(±3.24 SE) fish per hectare (ha) with maximum densities of 51.5 fish per ha. By comparing our observations to the results of biennial surveys conducted by the National Oceanic and Atmospheric Administration (NOAA) Coral Reef Ecosystem Division (CRED), we confirmed spatial consistency of the aggregation

  15. Grey and White Matter Correlates of Recent and Remote Autobiographical Memory Retrieval – Insights from the Dementias

    PubMed Central

    Irish, Muireann; Hornberger, Michael; El Wahsh, Shadi; Lam, Bonnie Y. K.; Lah, Suncica; Miller, Laurie; Hsieh, Sharpley; Hodges, John R.; Piguet, Olivier

    2014-01-01

    The capacity to remember self-referential past events relies on the integrity of a distributed neural network. Controversy exists, however, regarding the involvement of specific brain structures for the retrieval of recently experienced versus more distant events. Here, we explored how characteristic patterns of atrophy in neurodegenerative disorders differentially disrupt remote versus recent autobiographical memory. Eleven behavioural-variant frontotemporal dementia, 10 semantic dementia, 15 Alzheimer's disease patients and 14 healthy older Controls completed the Autobiographical Interview. All patient groups displayed significant remote memory impairments relative to Controls. Similarly, recent period retrieval was significantly compromised in behavioural-variant frontotemporal dementia and Alzheimer's disease, yet semantic dementia patients scored in line with Controls. Voxel-based morphometry and diffusion tensor imaging analyses, for all participants combined, were conducted to investigate grey and white matter correlates of remote and recent autobiographical memory retrieval. Neural correlates common to both recent and remote time periods were identified, including the hippocampus, medial prefrontal, and frontopolar cortices, and the forceps minor and left hippocampal portion of the cingulum bundle. Regions exclusively implicated in each time period were also identified. The integrity of the anterior temporal cortices was related to the retrieval of remote memories, whereas the posterior cingulate cortex emerged as a structure significantly associated with recent autobiographical memory retrieval. This study represents the first investigation of the grey and white matter correlates of remote and recent autobiographical memory retrieval in neurodegenerative disorders. Our findings demonstrate the importance of core brain structures, including the medial prefrontal cortex and hippocampus, irrespective of time period, and point towards the contribution of

  16. Analyzing the Energy and Power Consumption of Remote Memory Accesses in the OpenSHMEM Model

    SciTech Connect

    Jana, Siddhartha; Hernandez, Oscar R; Poole, Stephen W; Hsu, Chung-Hsing; Chapman, Barbara

    2014-01-01

    PGAS models like OpenSHMEM provide interfaces to explicitly initiate one-sided remote memory accesses among processes. In addition, the model also provides synchronizing barriers to ensure a consistent view of the distributed memory at different phases of an application. The incorrect use of such interfaces affects the scalability achievable while using a parallel programming model. This study aims at understanding the effects of these constructs on the energy and power consumption behavior of OpenSHMEM applications. Our experiments show that cost incurred in terms of the total energy and power consumed depends on multiple factors across the software and hardware stack. We conclude that there is a significant impact on the power consumed by the CPU and DRAM due to multiple factors including the design of the data transfer patterns within an application, the design of the communication protocols within a middleware, the architectural constraints laid by the interconnect solutions, and also the levels of memory hierarchy within a compute node. This work motivates treating energy and power consumption as important factors while designing compute solutions for current and future distributed systems.

  17. Medial temporal and neocortical contributions to remote memory for semantic narratives: evidence from amnesia.

    PubMed

    Verfaellie, Mieke; Bousquet, Kathryn; Keane, Margaret M

    2014-08-01

    Studies of remote memory for semantic facts and concepts suggest that hippocampal lesions lead to a temporally graded impairment that extends no more than ten years prior to the onset of amnesia. Such findings have led to the notion that once consolidated, semantic memories are represented neocortically and are no longer dependent on the hippocampus. Here, we examined the fate of well-established semantic narratives following medial temporal lobe (MTL) lesions. Seven amnesic patients, five with lesions restricted to the MTL and two with lesions extending into lateral temporal cortex (MTL+), were asked to recount fairy tales and bible stories that they rated as familiar. Narratives were scored for number and type of details, number of main thematic elements, and order in which the main thematic elements were recounted. In comparison to controls, patients with MTL lesions produced fewer details, but the number and order of main thematic elements generated was intact. By contrast, patients with MTL+ lesions showed a pervasive impairment, affecting not only the generation of details, but also the generation and ordering of main steps. These findings challenge the notion that, once consolidated, semantic memories are no longer dependent on the hippocampus for retrieval. Possible hippocampal contributions to the retrieval of detailed semantic narratives are discussed.

  18. Medial Temporal and Neocortical Contributions to Remote Memory for Semantic Narratives: Evidence from Amnesia

    PubMed Central

    Verfaellie, Mieke; Bousquet, Kathryn; Keane, Margaret M.

    2014-01-01

    Studies of remote memory for semantic facts and concepts suggest that hippocampal lesions lead to a temporally graded impairment that extends no more than ten years prior to the onset of amnesia. Such findings have led to the notion that once consolidated, semantic memories are represented neocortically and are no longer dependent on the hippocampus. Here, we examined the fate of well-established semantic narratives following medial temporal lobe (MTL) lesions. Seven amnesic patients, five with lesions restricted to the MTL and two with lesions extending into lateral temporal cortex (MTL+), were asked to recount fairy tales and bible stories that they rated as familiar. Narratives were scored for number and type of details, number of main thematic elements, and order in which the main thematic elements were recounted. In comparison to controls, patients with MTL lesions produced fewer details, but the number and order of main thematic elements generated was intact. By contrast, patients with MTL+ lesions showed a pervasive impairment, affecting not only the generation of details, but also the generation and ordering of main steps. These findings challenge the notion that, once consolidated, semantic memories are no longer dependent on the hippocampus for retrieval. Possible hippocampal contributions to the retrieval of detailed semantic narratives are discussed. PMID:24953960

  19. Optimization of multisource information fusion for resource management with remote sensing imagery: an aggregate regularization method with neural network implementation

    NASA Astrophysics Data System (ADS)

    Shkvarko, Yuriy, IV; Butenko, Sergiy

    2006-05-01

    We address a new approach to the problem of improvement of the quality of multi-grade spatial-spectral images provided by several remote sensing (RS) systems as required for environmental resource management with the use of multisource RS data. The problem of multi-spectral reconstructive imaging with multisource information fusion is stated and treated as an aggregated ill-conditioned inverse problem of reconstruction of a high-resolution image from the data provided by several sensor systems that employ the same or different image formation methods. The proposed fusionoptimization technique aggregates the experiment design regularization paradigm with neural-network-based implementation of the multisource information fusion method. The maximum entropy (ME) requirement and projection regularization constraints are posed as prior knowledge for fused reconstruction and the experiment-design regularization methodology is applied to perform the optimization of multisource information fusion. Computationally, the reconstruction and fusion are accomplished via minimization of the energy function of the proposed modified multistate Hopfield-type neural network (NN) that integrates the model parameters of all systems incorporating a priori information, aggregate multisource measurements and calibration data. The developed theory proves that the designed maximum entropy neural network (MENN) is able to solve the multisource fusion tasks without substantial complication of its computational structure independent on the number of systems to be fused. For each particular case, only the proper adjustment of the MENN's parameters (i.e. interconnection strengths and bias inputs) should be accomplished. Simulation examples are presented to illustrate the good overall performance of the fused reconstruction achieved with the developed MENN algorithm applied to the real-world multi-spectral environmental imagery.

  20. Towards a Low-Cost Remote Memory Attestation for the Smart Grid

    PubMed Central

    Yang, Xinyu; He, Xiaofei; Yu, Wei; Lin, Jie; Li, Rui; Yang, Qingyu; Song, Houbing

    2015-01-01

    In the smart grid, measurement devices may be compromised by adversaries, and their operations could be disrupted by attacks. A number of schemes to efficiently and accurately detect these compromised devices remotely have been proposed. Nonetheless, most of the existing schemes detecting compromised devices depend on the incremental response time in the attestation process, which are sensitive to data transmission delay and lead to high computation and network overhead. To address the issue, in this paper, we propose a low-cost remote memory attestation scheme (LRMA), which can efficiently and accurately detect compromised smart meters considering real-time network delay and achieve low computation and network overhead. In LRMA, the impact of real-time network delay on detecting compromised nodes can be eliminated via investigating the time differences reported from relay nodes. Furthermore, the attestation frequency in LRMA is dynamically adjusted with the compromised probability of each node, and then, the total number of attestations could be reduced while low computation and network overhead can be achieved. Through a combination of extensive theoretical analysis and evaluations, our data demonstrate that our proposed scheme can achieve better detection capacity and lower computation and network overhead in comparison to existing schemes. PMID:26307998

  1. Towards a Low-Cost Remote Memory Attestation for the Smart Grid.

    PubMed

    Yang, Xinyu; He, Xiaofei; Yu, Wei; Lin, Jie; Li, Rui; Yang, Qingyu; Song, Houbing

    2015-08-21

    In the smart grid, measurement devices may be compromised by adversaries, and their operations could be disrupted by attacks. A number of schemes to efficiently and accurately detect these compromised devices remotely have been proposed. Nonetheless, most of the existing schemes detecting compromised devices depend on the incremental response time in the attestation process, which are sensitive to data transmission delay and lead to high computation and network overhead. To address the issue, in this paper, we propose a low-cost remote memory attestation scheme (LRMA), which can efficiently and accurately detect compromised smart meters considering real-time network delay and achieve low computation and network overhead. In LRMA, the impact of real-time network delay on detecting compromised nodes can be eliminated via investigating the time differences reported from relay nodes. Furthermore, the attestation frequency in LRMA is dynamically adjusted with the compromised probability of each node, and then, the total number of attestations could be reduced while low computation and network overhead can be achieved. Through a combination of extensive theoretical analysis and evaluations, our data demonstrate that our proposed scheme can achieve better detection capacity and lower computation and network overhead in comparison to existing schemes.

  2. Brain Region-Specific Activity Patterns after Recent or Remote Memory Retrieval of Auditory Conditioned Fear

    ERIC Educational Resources Information Center

    Kwon, Jeong-Tae; Jhang, Jinho; Kim, Hyung-Su; Lee, Sujin; Han, Jin-Hee

    2012-01-01

    Memory is thought to be sparsely encoded throughout multiple brain regions forming unique memory trace. Although evidence has established that the amygdala is a key brain site for memory storage and retrieval of auditory conditioned fear memory, it remains elusive whether the auditory brain regions may be involved in fear memory storage or…

  3. Peripheral orthopaedic surgery down-regulates hippocampal brain-derived neurotrophic factor and impairs remote memory in mouse.

    PubMed

    Fidalgo, A R; Cibelli, M; White, J P M; Nagy, I; Noormohamed, F; Benzonana, L; Maze, M; Ma, D

    2011-09-08

    Peripheral orthopaedic surgery induces a profound inflammatory response. This includes a substantial increase in cytokines and, especially, in the level of interleukin (IL)-1β in the hippocampus, which has been shown to impair hippocampal-dependent memory in mice. We have employed two tests of contextual remote memory to demonstrate that the inflammatory response to surgical insult in mice also results in impairment of remote memory associated with prefrontal cortex (PFC). We have also found that, under the conditions presented in the social interaction test, peripheral orthopaedic surgery does not increase anxiety-like behaviour in our animal model. Although such surgery induces an increase in the level of IL-1β in the hippocampus, it fails to do so in the PFC. Peripheral orthopaedic surgery also results in a reduction in the level of hippocampal brain-derived neurotrophic factor (BDNF) and this may contribute, in part, to the memory impairment found after such surgery. Our data suggest that a reduction in the level of hippocampal BDNF and an increase in the level of hippocampal IL-1β following surgery may affect the transference of fear memory in the mouse brain.

  4. A Conceptual Approach to Assimilating Remote Sensing Data to Improve Soil Moisture Profile Estimates in a Surface Flux/Hydrology Model. 2; Aggregation

    NASA Technical Reports Server (NTRS)

    Schamschula, Marius; Crosson, William L.; Inguva, Ramarao; Yates, Thomas; Laymen, Charles A.; Caulfield, John

    1998-01-01

    This is a follow up on the preceding presentation by Crosson. The grid size for remote microwave measurements is much coarser than the hydrological model computational grids. To validate the hydrological models with measurements we propose mechanisms to aggregate the hydrological model outputs for soil moisture to allow comparison with measurements. Weighted neighborhood averaging methods are proposed to facilitate the comparison. We will also discuss such complications as misalignment, rotation and other distortions introduced by a generalized sensor image.

  5. Evaluating OpenSHMEM Explicit Remote Memory Access Operations and Merged Requests

    SciTech Connect

    Boehm, Swen; Pophale, Swaroop S; Gorentla Venkata, Manjunath

    2016-01-01

    The OpenSHMEM Library Specification has evolved consid- erably since version 1.0. Recently, non-blocking implicit Remote Memory Access (RMA) operations were introduced in OpenSHMEM 1.3. These provide a way to achieve better overlap between communication and computation. However, the implicit non-blocking operations do not pro- vide a separate handle to track and complete the individual RMA opera- tions. They are guaranteed to be completed after either a shmem quiet(), shmem barrier() or a shmem barrier all() is called. These are global com- pletion and synchronization operations. Though this semantic is expected to achieve a higher message rate for the applications, the drawback is that it does not allow fine-grained control over the completion of RMA operations. In this paper, first, we introduce non-blocking RMA operations with requests, where each operation has an explicit request to track and com- plete the operation. Second, we introduce interfaces to merge multiple requests into a single request handle. The merged request tracks multiple user-selected RMA operations, which provides the flexibility of tracking related communication operations with one request handle. Lastly, we explore the implications in terms of performance, productivity, usability and the possibility of defining different patterns of communication via merging of requests. Our experimental results show that a well designed and implemented OpenSHMEM stack can hide the overhead of allocating and managing the requests. The latency of RMA operations with requests is similar to blocking and implicit non-blocking RMA operations. We test our implementation with the Scalable Synthetic Compact Applications (SSCA #1) benchmark and observe that using RMA operations with requests and merging of these requests outperform the implementation using blocking RMA operations and implicit non-blocking operations by 49% and 74% respectively.

  6. Formation of hippocampal mHTT aggregates leads to impaired spatial memory, hippocampal activation and adult neurogenesis.

    PubMed

    Schwab, L C; Richetin, K; Barker, R A; Déglon, N

    2017-03-09

    Huntington's disease (HD) is a genetic neurodegenerative disorder characterized by a triad of motor, psychiatric and cognitive deficits with the latter classically attributed to disruption of fronto-striatal circuits. However, emerging evidence suggests that some of the cognitive deficits in HD may have their origin in other structures including the hippocampus. Hippocampal abnormalities have been reported in HD mouse models particularly in terms of performance on the Morris Water Maze. However, in these animals, it is difficult to be certain whether the spatial memory deficits are due to local pathology within this structure or their poor mobility and motivation. Thus, a better model of hippocampal dysfunction in HD is needed especially given that we have previously shown that patients with HD have hippocampal-related problems from the very earliest stages of disease. In this study, our aim was therefore to understand the cellular and behavioural consequences of local overexpression of mutant huntingtin (mHTT) in the hippocampus of adult mice. We found that a targeted injection of a lentivirus, encoding an N-terminal of mHTT with 82 CAG repeats, into the murine hippocampus led to the focal formation of mHTT aggregates, long-term spatial memory impairments with decreased neurogenesis and expression of the immediate early gene c-fos. This study has therefore shown for the first time that local expression of mHTT in the dentate gyrus has deleterious effects, including its neurogenic capacity, with functional behavioural consequences, which fits well with recent data on hippocampal deficits seen in patients with HD.

  7. Old-new ERP effects and remote memories: the late parietal effect is absent as recollection fails whereas the early mid-frontal effect persists as familiarity is retained

    PubMed Central

    Tsivilis, Dimitris; Allan, Kevin; Roberts, Jenna; Williams, Nicola; Downes, John Joseph; El-Deredy, Wael

    2015-01-01

    Understanding the electrophysiological correlates of recognition memory processes has been a focus of research in recent years. This study investigated the effects of retention interval on recognition memory by comparing memory for objects encoded four weeks (remote) or 5 min (recent) before testing. In Experiment 1, event related potentials (ERPs) were acquired while participants performed a yes-no recognition memory task involving remote, recent and novel objects. Relative to correctly rejected new items, remote and recent hits showed an attenuated frontal negativity from 300–500 ms post-stimulus. This effect, also known as the FN400, has been previously associated with familiarity memory. Recent and remote recognition ERPs did not differ from each other at this time-window. By contrast, recent but not remote recognition showed increased parietal positivity from around 500 ms post-stimulus. This late parietal effect (LPE), which is considered a correlate of recollection-related processes, also discriminated between recent and remote memories. A second, behavioral experiment confirmed that remote memories unlike recent memories were based almost exclusively on familiarity. These findings support the idea that the FN400 and LPE are indices of familiarity and recollection memory, respectively and show that remote and recent memories are functionally and anatomically distinct. PMID:26528163

  8. Memory

    MedlinePlus

    ... it has to decide what is worth remembering. Memory is the process of storing and then remembering this information. There are different types of memory. Short-term memory stores information for a few ...

  9. Hippocampal Infusion of Zeta Inhibitory Peptide Impairs Recent, but Not Remote, Recognition Memory in Rats

    PubMed Central

    Hales, Jena B.; Ocampo, Amber C.; Broadbent, Nicola J.; Clark, Robert E.

    2015-01-01

    Spatial memory in rodents can be erased following the infusion of zeta inhibitory peptide (ZIP) into the dorsal hippocampus via indwelling guide cannulas. It is believed that ZIP impairs spatial memory by reversing established late-phase long-term potentiation (LTP). However, it is unclear whether other forms of hippocampus-dependent memory, such as recognition memory, are also supported by hippocampal LTP. In the current study, we tested recognition memory in rats following hippocampal ZIP infusion. In order to combat the limited targeting of infusions via cannula, we implemented a stereotaxic approach for infusing ZIP throughout the dorsal, intermediate, and ventral hippocampus. Rats infused with ZIP 3–7 days after training on the novel object recognition task exhibited impaired object recognition memory compared to control rats (those infused with aCSF). In contrast, rats infused with ZIP 1 month after training performed similar to control rats. The ability to form new memories after ZIP infusions remained intact. We suggest that enhanced recognition memory for recent events is supported by hippocampal LTP, which can be reversed by hippocampal ZIP infusion. PMID:26380123

  10. Extinction after Retrieval: Effects on the Associative and Nonassociative Components of Remote Contextual Fear Memory

    ERIC Educational Resources Information Center

    Costanzi, Marco; Cannas, Sara; Saraulli, Daniele; Rossi-Arnaud, Clelia; Cestari, Vincenzo

    2011-01-01

    Long-lasting memories of adverse experiences are essential for individuals' survival but are also involved, in the form of recurrent recollections of the traumatic experience, in the aetiology of anxiety diseases (e.g., post-traumatic stress disorder [PTSD]). Extinction-based erasure of fear memories has long been pursued as a behavioral way to…

  11. Recall of Remote Episodic Memories Can Appear Deficient because of a Gist-Based Retrieval Orientation

    ERIC Educational Resources Information Center

    Rudoy, John D.; Weintraub, Sandra; Paller, Ken A.

    2009-01-01

    Determining whether patients with amnesia can succeed in remembering their distant past has pivotal implications for theories of memory storage. However, various factors influence recall. We speculated that some patients with anterograde amnesia adopt a gist-based retrieval orientation for memories from all time periods, thereby exaggerating…

  12. Mental space travel: damage to posterior parietal cortex prevents egocentric navigation and reexperiencing of remote spatial memories.

    PubMed

    Ciaramelli, Elisa; Rosenbaum, R Shayna; Solcz, Stephanie; Levine, Brian; Moscovitch, Morris

    2010-05-01

    The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the posterior parietal cortex (PPC) might support egocentric representations. To date, however, few studies have examined long-standing egocentric representations of environments learned long ago. Here we tested 7 patients with focal lesions in PPC and 12 normal controls in remote spatial memory tasks, including 2 tasks reportedly reliant on allocentric representations (distance and proximity judgments) and 2 tasks reportedly reliant on egocentric representations (landmark sequencing and route navigation; see Rosenbaum, Ziegler, Winocur, Grady, & Moscovitch, 2004). Patients were unimpaired in distance and proximity judgments. In contrast, they all failed in route navigation, and left-lesioned patients also showed marginally impaired performance in landmark sequencing. Patients' subjective experience associated with navigation was impoverished and disembodied compared with that of the controls. These results suggest that PPC is crucial for accessing remote spatial memories within an egocentric reference frame that enables both navigation and reexperiencing. Additionally, PPC was found to be necessary to implement specific aspects of allocentric navigation with high demands on spontaneous retrieval.

  13. Memory.

    ERIC Educational Resources Information Center

    McKean, Kevin

    1983-01-01

    Discusses current research (including that involving amnesiacs and snails) into the nature of the memory process, differentiating between and providing examples of "fact" memory and "skill" memory. Suggests that three brain parts (thalamus, fornix, mammilary body) are involved in the memory process. (JN)

  14. Aggregated effects of combining daily milk consumption and aerobic exercise on short-term memory and sustained attention among female students.

    PubMed

    Leong, In-Tyng; Moghadam, Sedigheh; Hashim, Hairul A

    2015-02-01

    Regular aerobic exercise and milk consumption have been found to have positive effects on certain cognitive functions such as short-term memory and sustained attention. However, aggregated effects of combining these modalities have not been explored. This study examined the combined effects of milk supplementation and aerobic exercise on the short-term memory and sustained attention of female students aged 16 yr. (N = 81). The intervention involved serving of 250 ml of regular milk during school days and/or a 1-hr. aerobic exercise period twice per week for 6 weeks. The Digit Span Test and Digit Vigilance Test were used to measure short-term memory and sustained attention, respectively. The combination group (milk and exercise) and exercise group performed significantly better than did the milk and control groups in terms of short-term memory. No significant interaction or group differences were found for sustained attention. The results suggest benefits of regular exercise for students' short-term memory.

  15. Retrosplenial Cortex Is Required for the Retrieval of Remote Memory for Auditory Cues

    ERIC Educational Resources Information Center

    Todd, Travis P.; Mehlman, Max L.; Keene, Christopher S.; DeAngeli, Nicole E.; Bucci, David J.

    2016-01-01

    The retrosplenial cortex (RSC) has a well-established role in contextual and spatial learning and memory, consistent with its known connectivity with visuo-spatial association areas. In contrast, RSC appears to have little involvement with delay fear conditioning to an auditory cue. However, all previous studies have examined the contribution of…

  16. Neurogenesis Interferes with the Retrieval of Remote Memories: Forgetting in Neurocomputational Terms

    ERIC Educational Resources Information Center

    Weisz, Victoria I.; Argibay, Pablo F.

    2012-01-01

    In contrast to models and theories that relate adult neurogenesis with the processes of learning and memory, almost no solid hypotheses have been formulated that involve a possible neurocomputational influence of adult neurogenesis on forgetting. Based on data from a previous study that implemented a simple but complete model of the main…

  17. Remote Spatial Memory and the Hippocampus: Effect of Early and Extensive Training in the Radial Maze

    ERIC Educational Resources Information Center

    Ramos, Juan M. J.

    2009-01-01

    In a previous study we showed a temporally graded retrograde amnesia after hippocampal lesions when rats learned a spatial reference memory task in which two types of signals simultaneously indicated the goal arm (shape of the experimental room and extramaze landmarks). To investigate the effect that the navigational demands of the task have on…

  18. Remediating Viking Origins: Genetic Code as Archival Memory of the Remote Past

    PubMed Central

    King, Turi; Brown, Steven D

    2013-01-01

    This article introduces some early data from the Leverhulme Trust-funded research programme, ‘The Impact of the Diasporas on the Making of Britain: evidence, memories, inventions’. One of the interdisciplinary foci of the programme, which incorporates insights from genetics, history, archaeology, linguistics and social psychology, is to investigate how genetic evidence of ancestry is incorporated into identity narratives. In particular, we investigate how ‘applied genetic history’ shapes individual and familial narratives, which are then situated within macro-narratives of the nation and collective memories of immigration and indigenism. It is argued that the construction of genetic evidence as a ‘gold standard’ about ‘where you really come from’ involves a remediation of cultural and archival memory, in the construction of a ‘usable past’. This article is based on initial questionnaire data from a preliminary study of those attending DNA collection sessions in northern England. It presents some early indicators of the perceived importance of being of Viking descent among participants, notes some emerging patterns and considers the implications for contemporary debates on migration, belonging and local and national identity. PMID:24179286

  19. The impact of multiple memory formation on dendritic complexity in the hippocampus and anterior cingulate cortex assessed at recent and remote time points

    PubMed Central

    Wartman, Brianne C.; Holahan, Matthew R.

    2014-01-01

    Consolidation processes, involving synaptic and systems level changes, are suggested to stabilize memories once they are formed. At the synaptic level, dendritic structural changes are associated with long-term memory storage. At the systems level, memory storage dynamics between the hippocampus and anterior cingulate cortex (ACC) may be influenced by the number of sequentially encoded memories. The present experiment utilized Golgi-Cox staining and neuron reconstruction to examine recent and remote structural changes in the hippocampus and ACC following training on three different behavioral procedures. Rats were trained on one hippocampal-dependent task only (a water maze task), two hippocampal-dependent tasks (a water maze task followed by a radial arm maze task), or one hippocampal-dependent and one non-hippocampal-dependent task (a water maze task followed by an operant conditioning task). Rats were euthanized recently or remotely. Brains underwent Golgi-Cox processing and neurons were reconstructed using Neurolucida software (MicroBrightField, Williston, VT, USA). Rats trained on two hippocampal-dependent tasks displayed increased dendritic complexity compared to control rats, in neurons examined in both the ACC and hippocampus at recent and remote time points. Importantly, this behavioral group showed consistent, significant structural differences in the ACC compared to the control group at the recent time point. These findings suggest that taxing the demand placed upon the hippocampus, by training rats on two hippocampal-dependent tasks, engages synaptic and systems consolidation processes in the ACC at an accelerated rate for recent and remote storage of spatial memories. PMID:24795581

  20. Analysis of coherent activity between retrosplenial cortex, hippocampus, thalamus, and anterior cingulate cortex during retrieval of recent and remote context fear memory.

    PubMed

    Corcoran, Kevin A; Frick, Brendan J; Radulovic, Jelena; Kay, Leslie M

    2016-01-01

    Memory for contextual fear conditioning relies upon the retrosplenial cortex (RSC) regardless of how long ago conditioning occurred, whereas areas connected to the RSC, such as the dorsal hippocampus (DH) and anterior cingulate cortex (ACC) appear to play time-limited roles. To better understand whether these brain regions functionally interact during memory processing and how the passage of time affects these interactions, we simultaneously recorded local field potentials (LFPs) from these three regions as well as anterior dorsal thalamus (ADT), which provides one of the strongest inputs to RSC, and measured coherence of oscillatory activity within the theta (4-12Hz) and gamma (30-80Hz) frequency bands. We identified changes of theta coherence related to encoding, retrieval, and extinction of context fear, whereas changes in gamma coherence were restricted to fear extinction. Specifically, exposure to a novel context and retrieval of recently acquired fear conditioning memory were associated with increased theta coherence between RSC and all three other structures. In contrast, RSC-DH and RSC-ADT theta coherence were decreased in mice that successfully retrieved, relative to mice that failed to retrieve, remote memory. Greater RSC-ADT theta and gamma coherence were observed during recent, compared to remote, extinction of freezing responses. Thus, the degree of coherence between RSC and connected brain areas may predict and contribute to context memory retrieval and retrieval-related phenomena such as fear extinction. Importantly, although theta coherence in this circuit increases during memory encoding and retrieval of recent memory, failure to decrease RSC-DH theta coherence might be linked to retrieval deficit in the long term, and possibly contribute to aberrant memory processing characteristic of neuropsychiatric disorders.

  1. Conduction Aphasia, Sensory-Motor Integration, and Phonological Short-term Memory – an Aggregate analysis of Lesion and fMRI data

    PubMed Central

    Buchsbaum, Bradley R.; Baldo, Juliana; Okada, Kayoko; Berman, Karen F.; Dronkers, Nina; D’Esposito, Mark; Hickok, Gregory

    2011-01-01

    Conduction aphasia is a language disorder characterized by frequent speech errors, impaired verbatim repetition, a deficit in phonological short-term memory, and naming difficulties in the presence of otherwise fluent and grammatical speech output. While traditional models of conduction aphasia have typically implicated white matter pathways, recent advances in lesions reconstruction methodology applied to groups of patients have implicated left temporoparietal zones. Parallel work using functional magnetic resonance imaging (fMRI) has pinpointed a region in the posterior most portion of the left planum temporale, area Spt, which is critical for phonological working memory. Here we show that the region of maximal lesion overlap in a sample of 14 patients with conduction aphasia perfectly circumscribes area Spt, as defined in an aggregate fMRI analysis of 105 subjects performing a phonological working memory task. We provide a review of the evidence supporting the idea that Spt is an interface site for the integration of sensory and vocal tract-related motor representations of complex sound sequences, such as speech and music and show how the symptoms of conduction aphasia can be explained by damage to this system. PMID:21256582

  2. Acute administration of nicotine into the higher order auditory Te2 cortex specifically decreases the fear-related charge of remote emotional memories.

    PubMed

    Cambiaghi, Marco; Grosso, Anna; Renna, Annamaria; Concina, Giulia; Sacchetti, Benedetto

    2015-12-01

    Nicotine elicits several behavioural effects on mood as well as on stress and anxiety processes. Recently, it was found that the higher order components of the sensory cortex, such as the secondary auditory cortex Te2, are essential for the long-term storage of remote fear memories. Therefore, in the present study, we examined the effects of acute nicotine injection into the higher order auditory cortex Te2, on the remote emotional memories of either threat or incentive experiences in rats. We found that intra-Te2 nicotine injection decreased the fear-evoked responses to a tone previously paired with footshock. This effect was cue- and dose-specific and was not due to any interference with auditory stimuli processing, innate anxiety and fear processes, or with motor responses. Nicotine acts acutely in the presence of threat stimuli but it did not determine the permanent degradation of the fear-memory trace, since memories tested one week after nicotine injection were unaffected. Remarkably, nicotine did not affect the memory of a similar tone that was paired to incentive stimuli. We conclude from our results that nicotine, when acting acutely in the auditory cortex, relieves the fear charge embedded by learned stimuli.

  3. Memories.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    1998-01-01

    This theme issue of the journal "Exploring" covers the topic of "memories" and describes an exhibition at San Francisco's Exploratorium that ran from May 22, 1998 through January 1999 and that contained over 40 hands-on exhibits, demonstrations, artworks, images, sounds, smells, and tastes that demonstrated and depicted the biological,…

  4. The time course of systems consolidation of spatial memory from recent to remote retention: A comparison of the Immediate Early Genes Zif268, c-Fos and Arc.

    PubMed

    Barry, Daniel N; Coogan, Andrew N; Commins, Sean

    2016-02-01

    Systems consolidation is a process involving the stabilisation of memory traces in the neocortex over time. The medial prefrontal cortex becomes increasingly important during the retrieval of older memories, however the timescale of its involvement is unclear, and the contribution of other neocortical brain regions to remote memory have received little attention. The Immediate Early Genes (IEGs) Zif268, c-Fos and Arc have been utilised as markers of neural activity during spatial memory retrieval, however the lack of a direct comparison between them hinders the interpretation of results. To address these questions, we examined the expression of Zif268, Arc and c-Fos protein in the medial prefrontal cortex, as well as the hippocampus, and the entorhinal, perirhinal, retrosplenial and parietal cortices of male Wistar rats following a probe trial of the Morris water maze either one day, seven days, 14 days or 30 days after acquisition. Activity of the medial prefrontal cortex during retrieval, as measured by all three IEGs, increased in correspondence with the age of the memory, reaching significance between 14 and 30 days. Similar increases in c-Fos and Arc were observed over the course of consolidation in other neocortical and parahippocampal areas, however this pattern was not observed with Zif268. Activity of the hippocampus remained largely unchanged across retention intervals. These findings suggest that systems consolidation of spatial memory takes at least two weeks, are consistent with an ongoing role for the hippocampus in the retrieval of spatial memory, and suggest that c-Fos and Arc may be a more sensitive measure of neural activity in response to behavioural tasks than Zif268.

  5. Reconsolidation-induced rescue of a remote fear memory blocked by an early cortical inhibition: Involvement of the anterior cingulate cortex and the mediation by the thalamic nucleus reuniens.

    PubMed

    Sierra, Rodrigo O; Pedraza, Lizeth K; Zanona, Querusche K; Santana, Fabiana; Boos, Flávia Z; Crestani, Ana P; Haubrich, Josué; de Oliveira Alvares, Lucas; Calcagnotto, Maria Elisa; Quillfeldt, Jorge A

    2017-02-08

    Systems consolidation is a time-dependent reorganization process involving neocortical and hippocampal networks underlying memory storage and retrieval. The involvement of the hippocampus during acquisition is well described; however we know much less about the concomitant contribution of cortical activity levels to the formation of stable remote memories. Here, after a reversible pharmacological inhibition of the anterior cingulate cortex (ACC) during the acquisition of a contextual fear conditioning, retrieval of both recent and remote memories were impaired, an effect that was reverted by a single memory reactivation session 48 h after training, through a destabilization-dependent mechanism interpreted as reconsolidation, that restored the normal course of systems consolidation in order to rescue a remote memory. Next we have shown that the integrity of both the anterior cingulate cortex and the thalamic nucleus reuniens (RE) were required for this reactivation-induced memory rescue. Because lidocaine infused into the RE inhibited LTP induction in the CA1-anterior cingulate cortex pathways, it seems that RE is a necessary component of the circuit underlying systems consolidation, mediating communication between dorsal hippocampus and cortical areas. To our notice, this is the first demonstration of the rescue of remote memories disrupted by ACC inhibition during acquisition, via a reconsolidation-driven mechanism. We have also shown the importance of RE to ensure the interconnection among brain areas that collectively seem to control the natural course of systems consolidation and allow the persistence of relevant emotional engrams. © 2017 Wiley Periodicals, Inc.

  6. The double-H maze test, a novel, simple, water-escape memory task: acquisition, recall of recent and remote memory, and effects of systemic muscarinic or NMDA receptor blockade during training.

    PubMed

    Pol-Bodetto, Sarah; Jeltsch-David, Hélène; Lecourtier, Lucas; Rusnac, Nathalia; Mam-Lam-Fook, Célia; Cosquer, Brigitte; Geiger, Karin; Cassel, Jean-Christophe

    2011-03-17

    To explore spatial cognition in rodents, research uses maze tasks, which differ in complexity, number of goals and pathways, behavioural flexibility, memory duration, but also in the experimenter's control over the strategy developed to reach a goal (e.g., allocentric vs. egocentric). This study aimed at validating a novel spatial memory test: the double-H maze test. The transparent device made of an alley with two opposite arms at each extremity and two in its centre is flooded. An escape platform is submerged in one arm. For experiments 1-3, rats were released in unpredictable sequences from one of both central arms to favour an allocentric approach of the task. Experiment 1 (3 trials/day over 6 days) demonstrated classical learning curves and evidence for recent and nondegraded remote memory performance. Experiment 2 (2 days, 3 trials/day) showed a dose-dependent alteration of task acquisition/consolidation by muscarinic or NMDA receptor blockade; these drug effects vanished with sustained training (experiment 3; 4 days, 3 trials/day). Experiment 4 oriented rats towards a procedural (egocentric) approach of the task. Memory was tested in a misleading probe trial. Most rats immediately switched from response learning-based to place learning-based behaviour, but only when their initial view on environmental cues markedly differed between training and probe trials. Because this simple task enables the formation of a relatively stable memory trace, it could be particularly adapted to study consolidation processes at a system level or/and the interplay between procedural and declarative-like memory systems.

  7. Recent versus Remote: Flashbulb Memory for 9/11 and Self-Selected Events from the Reminiscence Bump

    ERIC Educational Resources Information Center

    Denver, Jenny Y.; Lane, Sean M.; Cherry, Katie E.

    2010-01-01

    In two related studies, we examined flashbulb memories acquired from different points in the lifespan in younger and older adults. When asked to remember flashbulb memories from their lives, older adults were most likely to recall events from the reminiscence bump (Study 1A). In Study 1B, younger and older adults recalled 9/11 and a personal…

  8. Late Enrichment Maintains Accurate Recent and Remote Spatial Memory Only in Aged Rats That Were Unimpaired When Middle Aged

    ERIC Educational Resources Information Center

    Fuchs, Fanny; Herbeaux, Karine; Aufrere, Noémie; Kelche, Christian; Mathis, Chantal; Barbelivien, Alexandra; Majchrzak, Monique

    2016-01-01

    Exposure of rodents to a stimulating environment has beneficial effects on some cognitive functions that are impaired during physiological aging, and especially spatial reference memory. The present study investigated whether environmental enrichment rescues these functions in already declining subjects and/or protects them from subsequent…

  9. [Neural correlates of memory].

    PubMed

    Fujii, Toshikatsu

    2013-01-01

    Memory can be divided into several types, although all of them involve three successive processes: encoding, storage, and retrieval. In terms of the duration of retention, neurologists classify memory into immediate, recent, and remote memories, whereas psychologists classify memory into short-term and long-term memories. In terms of the content, episodic, semantic, and procedural memories are considered to be different types of memory. Furthermore, researchers on memory have proposed relatively new concepts of memory, i.e., working memory and prospective memory. This article first provides explanations for these several types of memory. Next, neuropsychological characteristics of amnesic syndrome are briefly outlined. Finally, how several different types of memory are affected (or preserved) in patients with amnesic syndrome is described.

  10. A trade-off between local and distributed information processing associated with remote episodic versus semantic memory.

    PubMed

    Heisz, Jennifer J; Vakorin, Vasily; Ross, Bernhard; Levine, Brian; McIntosh, Anthony R

    2014-01-01

    Episodic memory and semantic memory produce very different subjective experiences yet rely on overlapping networks of brain regions for processing. Traditional approaches for characterizing functional brain networks emphasize static states of function and thus are blind to the dynamic information processing within and across brain regions. This study used information theoretic measures of entropy to quantify changes in the complexity of the brain's response as measured by magnetoencephalography while participants listened to audio recordings describing past personal episodic and general semantic events. Personal episodic recordings evoked richer subjective mnemonic experiences and more complex brain responses than general semantic recordings. Critically, we observed a trade-off between the relative contribution of local versus distributed entropy, such that personal episodic recordings produced relatively more local entropy whereas general semantic recordings produced relatively more distributed entropy. Changes in the relative contributions of local and distributed entropy to the total complexity of the system provides a potential mechanism that allows the same network of brain regions to represent cognitive information as either specific episodes or more general semantic knowledge.

  11. Scaling Irregular Applications through Data Aggregation and Software Multithreading

    SciTech Connect

    Morari, Alessandro; Tumeo, Antonino; Chavarría-Miranda, Daniel; Villa, Oreste; Valero, Mateo

    2014-05-30

    Bioinformatics, data analytics, semantic databases, knowledge discovery are emerging high performance application areas that exploit dynamic, linked data structures such as graphs, unbalanced trees or unstructured grids. These data structures usually are very large, requiring significantly more memory than available on single shared memory systems. Additionally, these data structures are difficult to partition on distributed memory systems. They also present poor spatial and temporal locality, thus generating unpredictable memory and network accesses. The Partitioned Global Address Space (PGAS) programming model seems suitable for these applications, because it allows using a shared memory abstraction across distributed-memory clusters. However, current PGAS languages and libraries are built to target regular remote data accesses and block transfers. Furthermore, they usually rely on the Single Program Multiple Data (SPMD) parallel control model, which is not well suited to the fine grained, dynamic and unbalanced parallelism of irregular applications. In this paper we present {\\bf GMT} (Global Memory and Threading library), a custom runtime library that enables efficient execution of irregular applications on commodity clusters. GMT integrates a PGAS data substrate with simple fork/join parallelism and provides automatic load balancing on a per node basis. It implements multi-level aggregation and lightweight multithreading to maximize memory and network bandwidth with fine-grained data accesses and tolerate long data access latencies. A key innovation in the GMT runtime is its thread specialization (workers, helpers and communication threads) that realize the overall functionality. We compare our approach with other PGAS models, such as UPC running using GASNet, and hand-optimized MPI code on a set of typical large-scale irregular applications, demonstrating speedups of an order of magnitude.

  12. Aggregated Indexing of Biomedical Time Series Data.

    PubMed

    Woodbridge, Jonathan; Mortazavi, Bobak; Sarrafzadeh, Majid; Bui, Alex A T

    2012-09-01

    Remote and wearable medical sensing has the potential to create very large and high dimensional datasets. Medical time series databases must be able to efficiently store, index, and mine these datasets to enable medical professionals to effectively analyze data collected from their patients. Conventional high dimensional indexing methods are a two stage process. First, a superset of the true matches is efficiently extracted from the database. Second, supersets are pruned by comparing each of their objects to the query object and rejecting any objects falling outside a predetermined radius. This pruning stage heavily dominates the computational complexity of most conventional search algorithms. Therefore, indexing algorithms can be significantly improved by reducing the amount of pruning. This paper presents an online algorithm to aggregate biomedical times series data to significantly reduce the search space (index size) without compromising the quality of search results. This algorithm is built on the observation that biomedical time series signals are composed of cyclical and often similar patterns. This algorithm takes in a stream of segments and groups them to highly concentrated collections. Locality Sensitive Hashing (LSH) is used to reduce the overall complexity of the algorithm, allowing it to run online. The output of this aggregation is used to populate an index. The proposed algorithm yields logarithmic growth of the index (with respect to the total number of objects) while keeping sensitivity and specificity simultaneously above 98%. Both memory and runtime complexities of time series search are improved when using aggregated indexes. In addition, data mining tasks, such as clustering, exhibit runtimes that are orders of magnitudes faster when run on aggregated indexes.

  13. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1995-01-01

    Part of the 1994 Industrial Minerals Review. The production, consumption, and applications of construction aggregates are reviewed. In 1994, the production of construction aggregates, which includes crushed stone and construction sand and gravel combined, increased 7.7 percent to 2.14 Gt compared with the previous year. These record production levels are mostly a result of funding for highway construction work provided by the Intermodal Surface Transportation Efficiency Act of 1991. Demand is expected to increase for construction aggregates in 1995.

  14. Remote Effects of Hippocampal Sclerosis on Effective Connectivity during Working Memory Encoding: A Case of Connectional Diaschisis?

    PubMed Central

    Campo, Pablo; Garrido, Marta I.; Moran, Rosalyn J.; Maestú, Fernando; García-Morales, Irene; Gil-Nagel, Antonio; del Pozo, Francisco; Dolan, Raymond J.; Friston, Karl J.

    2012-01-01

    Accumulating evidence suggests a role for the medial temporal lobe (MTL) in working memory (WM). However, little is known concerning its functional interactions with other cortical regions in the distributed neural network subserving WM. To reveal these, we availed of subjects with MTL damage and characterized changes in effective connectivity while subjects engaged in WM task. Specifically, we compared dynamic causal models, extracted from magnetoencephalographic recordings during verbal WM encoding, in temporal lobe epilepsy patients (with left hippocampal sclerosis) and controls. Bayesian model comparison indicated that the best model (across subjects) evidenced bilateral, forward, and backward connections, coupling inferior temporal cortex (ITC), inferior frontal cortex (IFC), and MTL. MTL damage weakened backward connections from left MTL to left ITC, a decrease accompanied by strengthening of (bidirectional) connections between IFC and MTL in the contralesional hemisphere. These findings provide novel evidence concerning functional interactions between nodes of this fundamental cognitive network and sheds light on how these interactions are modified as a result of focal damage to MTL. The findings highlight that a reduced (top-down) influence of the MTL on ipsilateral language regions is accompanied by enhanced reciprocal coupling in the undamaged hemisphere providing a first demonstration of “connectional diaschisis.” PMID:21810779

  15. Remote Monitor Alarm System

    NASA Technical Reports Server (NTRS)

    Stute, Robert A. (Inventor); Galloway, F. Houston (Inventor); Medelius, Pedro J. (Inventor); Swindle, Robert W. (Inventor); Bierman, Tracy A. (Inventor)

    1996-01-01

    A remote monitor alarm system monitors discrete alarm and analog power supply voltage conditions at remotely located communications terminal equipment. A central monitoring unit (CMU) is connected via serial data links to each of a plurality of remote terminal units (RTUS) that monitor the alarm and power supply conditions of the remote terminal equipment. Each RTU can monitor and store condition information of both discrete alarm points and analog power supply voltage points in its associated communications terminal equipment. The stored alarm information is periodically transmitted to the CMU in response to sequential polling of the RTUS. The number of monitored alarm inputs and permissible voltage ranges for the analog inputs can be remotely configured at the CMU and downloaded into programmable memory at each RTU. The CMU includes a video display, a hard disk memory, a line printer and an audio alarm for communicating and storing the alarm information received from each RTU.

  16. Conduction Aphasia, Sensory-Motor Integration, and Phonological Short-Term Memory--An Aggregate Analysis of Lesion and fMRI Data

    ERIC Educational Resources Information Center

    Buchsbaum, Bradley R.; Baldo, Juliana; Okada, Kayoko; Berman, Karen F.; Dronkers, Nina; D'Esposito, Mark; Hickok, Gregory

    2011-01-01

    Conduction aphasia is a language disorder characterized by frequent speech errors, impaired verbatim repetition, a deficit in phonological short-term memory, and naming difficulties in the presence of otherwise fluent and grammatical speech output. While traditional models of conduction aphasia have typically implicated white matter pathways,…

  17. Aggregation server for grid-integrated vehicles

    DOEpatents

    Kempton, Willett

    2015-05-26

    Methods, systems, and apparatus for aggregating electric power flow between an electric grid and electric vehicles are disclosed. An apparatus for aggregating power flow may include a memory and a processor coupled to the memory to receive electric vehicle equipment (EVE) attributes from a plurality of EVEs, aggregate EVE attributes, predict total available capacity based on the EVE attributes, and dispatch at least a portion of the total available capacity to the grid. Power flow may be aggregated by receiving EVE operational parameters from each EVE, aggregating the received EVE operational parameters, predicting total available capacity based on the aggregated EVE operational parameters, and dispatching at least a portion of the total available capacity to the grid.

  18. Applying n-bit floating point numbers and integers, and the n-bit filter of HDF5 to reduce file sizes of remote sensing products in memory-sensitive environments

    NASA Astrophysics Data System (ADS)

    Zinke, Stephan

    2017-02-01

    Memory sensitive applications for remote sensing data require memory-optimized data types in remote sensing products. Hierarchical Data Format version 5 (HDF5) offers user defined floating point numbers and integers and the n-bit filter to create data types optimized for memory consumption. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) applies a compaction scheme to the disseminated products of the Day and Night Band (DNB) data of Suomi National Polar-orbiting Partnership (S-NPP) satellite's instrument Visible Infrared Imager Radiometer Suite (VIIRS) through the EUMETSAT Advanced Retransmission Service, converting the original 32 bits floating point numbers to user defined floating point numbers in combination with the n-bit filter for the radiance dataset of the product. The radiance dataset requires a floating point representation due to the high dynamic range of the DNB. A compression factor of 1.96 is reached by using an automatically determined exponent size and an 8 bits trailing significand and thus reducing the bandwidth requirements for dissemination. It is shown how the parameters needed for user defined floating point numbers are derived or determined automatically based on the data present in a product.

  19. Construction aggregates

    USGS Publications Warehouse

    Nelson, T.I.; Bolen, W.P.

    2007-01-01

    Construction aggregates, primarily stone, sand and gravel, are recovered from widespread naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size and sold loose or combined with portland cement or asphaltic cement to make concrete products to build roads, houses, buildings, and other structures. Much smaller quantities are used in agriculture, cement manufacture, chemical and metallurgical processes, glass production and many other products.

  20. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1996-01-01

    Part of the Annual Commodities Review 1995. Production of construction aggregates such as crushed stone and construction sand and gravel showed a marginal increase in 1995. Most of the 1995 increases were due to funding for highway construction work. The major areas of concern to the industry included issues relating to wetlands classification and the classification of crystalline silica as a probable human carcinogen. Despite this, an increase in demand is anticipated for 1996.

  1. Positive consequences of false memories.

    PubMed

    Howe, Mark L; Garner, Sarah R; Patel, Megan

    2013-01-01

    Previous research is replete with examples of the negative consequences of false memories. In the current research, we provide a different perspective on false memories and their development and demonstrate that false memories can have positive consequences. Specifically, we examined the role false memories play in subsequent problem-solving tasks. Children and adults studied and recalled neutral or survival-relevant lists of associated words. They then solved age-normed compound remote associates, some of whose solutions had been primed by false memories created when studying the previous lists. The results showed that regardless of age: (a) survival-related words were not only better recollected but were also more susceptible than neutral words to false memory illusions; and (b) survival-related false memories were better than neutral false memories as primes for problem-solving. These findings are discussed in the context of recent speculation concerning the positive consequences of false memories, and the adaptive nature of reconstructive memory.

  2. The Neural Substrates of Recognition Memory for Verbal Information: Spanning the Divide between Short- and Long-Term Memory

    ERIC Educational Resources Information Center

    Buchsbaum, Bradley R.; Padmanabhan, Aarthi; Berman, Karen Faith

    2011-01-01

    One of the classic categorical divisions in the history of memory research is that between short-term and long-term memory. Indeed, because memory for the immediate past (a few seconds) and memory for the relatively more remote past (several seconds and beyond) are assumed to rely on distinct neural systems, more often than not, memory research…

  3. Marine particle aggregate breakup in turbulent flows

    NASA Astrophysics Data System (ADS)

    Rau, Matthew; Ackleson, Steven; Smith, Geoffrey

    2016-11-01

    The dynamics of marine particle aggregate formation and breakup due to turbulence is studied experimentally. Aggregates of clay particles, initially in a quiescent aggregation tank, are subjected to fully developed turbulent pipe flow at Reynolds numbers of up to 25,000. This flow arrangement simulates the exposure of marine aggregates in coastal waters to a sudden turbulent event. Particle size distributions are measured by in-situ sampling of the small-angle forward volume scattering function and the volume concentration of the suspended particulate matter is quantified through light attenuation measurements. Results are compared to measurements conducted under laminar and turbulent flow conditions. At low shear rates, larger sized particles indicate that aggregation initially governs the particle dynamics. Breakup is observed when large aggregates are exposed to the highest levels of shear in the experiment. Models describing the aggregation and breakup rates of marine particles due to turbulence are evaluated with the population balance equation and results from the simulation and experiment are compared. Additional model development will more accurately describe aggregation dynamics for remote sensing applications in turbulent marine environments.

  4. Can False Memories Prime Problem Solutions?

    ERIC Educational Resources Information Center

    Howe, Mark L.; Garner, Sarah R.; Dewhurst, Stephen A.; Ball, Linden J.

    2010-01-01

    Previous research has suggested that false memories can prime performance on related implicit and explicit memory tasks. The present research examined whether false memories can also be used to prime higher order cognitive processes, namely, insight-based problem solving. Participants were asked to solve a number of compound remote associate task…

  5. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2002-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  6. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2000-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  7. Mechanical memory

    DOEpatents

    Gilkey, Jeffrey C.; Duesterhaus, Michelle A.; Peter, Frank J.; Renn, Rosemarie A.; Baker, Michael S.

    2006-08-15

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  8. Mechanical memory

    DOEpatents

    Gilkey, Jeffrey C.; Duesterhaus, Michelle A.; Peter, Frank J.; Renn, Rosemarie A.; Baker, Michael S.

    2006-05-16

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  9. Emotional content of true and false memories.

    PubMed

    Laney, Cara; Loftus, Elizabeth F

    2008-01-01

    Many people believe that emotional memories (including those that arise in therapy) are particularly likely to represent true events because of their emotional content. But is emotional content a reliable indicator of memory accuracy? The current research assessed the emotional content of participants' pre-existing (true) and manipulated (false) memories for childhood events. False memories for one of three emotional childhood events were planted using a suggestive manipulation and then compared, along several subjective dimensions, with other participants' true memories. On most emotional dimensions (e.g., how emotional was this event for you?), true and false memories were indistinguishable. On a few measures (e.g., intensity of feelings at the time of the event), true memories were more emotional than false memories in the aggregate, yet true and false memories were equally likely to be rated as uniformly emotional. These results suggest that even substantial emotional content may not reliably indicate memory accuracy.

  10. Thermodynamics of Protein Aggregation

    NASA Astrophysics Data System (ADS)

    Osborne, Kenneth L.; Barz, Bogdan; Bachmann, Michael; Strodel, Birgit

    Amyloid protein aggregation characterizes many neurodegenerative disorders, including Alzheimer's, Parkinson's, and Creutz- feldt-Jakob disease. Evidence suggests that amyloid aggregates may share similar aggregation pathways, implying simulation of full-length amyloid proteins is not necessary for understanding amyloid formation. In this study we simulate GNNQQNY, the N-terminal prion-determining domain of the yeast protein Sup35 to investigate the thermodynamics of structural transitions during aggregation. We use a coarse-grained model with replica-exchange molecular dynamics to investigate the association of 3-, 6-, and 12-chain GNNQQNY systems and we determine the aggregation pathway by studying aggregation states of GN- NQQNY. We find that the aggregation of the hydrophilic GNNQQNY sequence is mainly driven by H-bond formation, leading to the formation of /3-sheets from the very beginning of the assembly process. Condensation (aggregation) and ordering take place simultaneously, which is underpinned by the occurrence of a single heat capacity peak only.

  11. On mean type aggregation.

    PubMed

    Yager, R R

    1996-01-01

    We introduce and define the concept of mean aggregation of a collection of n numbers. We point out that the lack of associativity of this operation compounds the problem of the extending mean of n numbers to n+1 numbers. The closely related concepts of self identity and the centering property are introduced as one imperative for extending mean aggregation operators. The problem of weighted mean aggregation is studied. A new concept of prioritized mean aggregation is then introduced. We next show that the technique of selecting an element based upon the performance of a random experiment can be considered as a mean aggregation operation.

  12. Remote Sensing.

    ERIC Educational Resources Information Center

    Williams, Richard S., Jr.; Southworth, C. Scott

    1983-01-01

    The Landsat Program became the major event of 1982 in geological remote sensing with the successful launch of Landsat 4. Other 1982 remote sensing accomplishments, research, publications, (including a set of Landsat worldwide reference system index maps), and conferences are highlighted. (JN)

  13. Memory Matters

    MedlinePlus

    ... different parts. Some of them are important for memory. The hippocampus (say: hih-puh-KAM-pus) is one of the more important parts of the brain that processes memories. Old information and new information, or memories, are ...

  14. Mapping the Structure of Semantic Memory

    ERIC Educational Resources Information Center

    Morais, Ana Sofia; Olsson, Henrik; Schooler, Lael J.

    2013-01-01

    Aggregating snippets from the semantic memories of many individuals may not yield a good map of an individual's semantic memory. The authors analyze the structure of semantic networks that they sampled from individuals through a new snowball sampling paradigm during approximately 6 weeks of 1-hr daily sessions. The semantic networks of individuals…

  15. Shape Memory Actuator System

    DTIC Science & Technology

    1998-07-31

    The advantage in utilizing 15 shape-memory cables made of Nitinol for size reduction of the remote control actuator system is 1 Fi well suited for...a submarine environment because of its non-magnetic and corrosion resistance 17 properties. Use of thermoelastic Nitinol introduces other...problems because of the cooling and 18 resetting properties of Nitinol cables. It is therefore an important object of the present invention 19 on to

  16. Emergence of Collective Memories

    PubMed Central

    Lee, Sungmin; Ramenzoni, Verónica C.; Holme, Petter

    2010-01-01

    Background We understand the dynamics of the world around us as by associating pairs of events, where one event has some influence on the other. These pairs of events can be aggregated into a web of memories representing our understanding of an episode of history. The events and the associations between them need not be directly experienced—they can also be acquired by communication. In this paper we take a network approach to study the dynamics of memories of history. Methodology/Principal Findings First we investigate the network structure of a data set consisting of reported events by several individuals and how associations connect them. We focus our measurement on degree distributions, degree correlations, cycles (which represent inconsistencies as they would break the time ordering) and community structure. We proceed to model effects of communication using an agent-based model. We investigate the conditions for the memory webs of different individuals to converge to collective memories, how groups where the individuals have similar memories (but different from other groups) can form. Conclusions/Significance Our work outlines how the cognitive representation of memories and social structure can co-evolve as a contagious process. We generate some testable hypotheses including that the number of groups is limited as a function of the total population size. PMID:20824141

  17. Shape-Memory-Alloy Release Mechanism

    NASA Technical Reports Server (NTRS)

    Mckinnis, Darin

    1993-01-01

    Release-nut mechanism activated by electric current applied to shape-memory alloy. Separates attached objects quickly by remote control. Does not create hazard or cause damage. Shape-memory release-nut mechanism unaffected by moisture or vacuum. Requires sustained current lasting 5 seconds or longer, and insensitive to electromagnetic interference. Mechanism can be reused.

  18. Aggregations in Flatworms.

    ERIC Educational Resources Information Center

    Liffen, C. L.; Hunter, M.

    1980-01-01

    Described is a school project to investigate aggregations in flatworms which may be influenced by light intensity, temperature, and some form of chemical stimulus released by already aggregating flatworms. Such investigations could be adopted to suit many educational levels of science laboratory activities. (DS)

  19. Unbonded Aggregate Surface Roads

    DTIC Science & Technology

    2006-12-01

    are sufficiently angular and rough in texture, thus ensuring mixture stability. A popular asphalt mixture design method called Superpave Level 1...would not pass either of the Superpave aggregate requirements. Table 18 Additional Characteristics for the Fine Fraction Abbreviated Common Name...CBR values when compacted wet of optimum. This is likely attributable to their relatively high permeabilities . For soaked CBR tests, the aggregates

  20. Erosion of dust aggregates

    NASA Astrophysics Data System (ADS)

    Seizinger, A.; Krijt, S.; Kley, W.

    2013-12-01

    Aims: The aim of this work is to gain a deeper insight into how much different aggregate types are affected by erosion. Especially, it is important to study the influence of the velocity of the impacting projectiles. We also want to provide models for dust growth in protoplanetary disks with simple recipes to account for erosion effects. Methods: To study the erosion of dust aggregates we employed a molecular dynamics approach that features a detailed micro-physical model of the interaction of spherical grains. For the first time, the model has been extended by introducing a new visco-elastic damping force, which requires a proper calibration. Afterwards, different sample generation methods were used to cover a wide range of aggregate types. Results: The visco-elastic damping force introduced in this work turns out to be crucial to reproduce results obtained from laboratory experiments. After proper calibration, we find that erosion occurs for impact velocities of 5 ms-1 and above. Though fractal aggregates as formed during the first growth phase are most susceptible to erosion, we observe erosion of aggregates with rather compact surfaces as well. Conclusions: We find that bombarding a larger target aggregate with small projectiles results in erosion for impact velocities as low as a few ms-1. More compact aggregates suffer less from erosion. With increasing projectile size the transition from accretion to erosion is shifted to higher velocities. This allows larger bodies to grow through high velocity collisions with smaller aggregates.

  1. Charged Dust Aggregate Interactions

    NASA Astrophysics Data System (ADS)

    Matthews, Lorin; Hyde, Truell

    2015-11-01

    A proper understanding of the behavior of dust particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the dust aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions leading to the observed interactions. This research is funded by NSF Grant 1414523.

  2. Aggregate and the environment

    USGS Publications Warehouse

    Langer, William H.; Drew, Lawrence J.; Sachs, J.S.

    2004-01-01

    This book is designed to help you understand our aggregate resources-their importance, where they come from, how they are processed for our use, the environmental concerns related to their mining and processing, how those concerns are addressed, and the policies and regulations designed to safeguard workers, neighbors, and the environment from the negative impacts of aggregate mining. We hope this understanding will help prepare you to be involved in decisions that need to be made-individually and as a society-to be good stewards of our aggregate resources and our living planet.

  3. Durable fear memories require PSD-95

    PubMed Central

    Fitzgerald, Paul J.; Pinard, Courtney R.; Camp, Marguerite C.; Feyder, Michael; Sah, Anupam; Bergstrom, Hadley; Graybeal, Carolyn; Liu, Yan; Schlüter, Oliver; Grant, Seth G.N.; Singewald, Nicolas; Xu, Weifeng; Holmes, Andrew

    2014-01-01

    Traumatic fear memories are highly durable but also dynamic, undergoing repeated reactivation and rehearsal over time. While overly persistent fear memories underlie anxiety disorders such as posttraumatic stress disorder, the key neural and molecular mechanisms underlying fear memory durability remain unclear. Post-synaptic density 95 (PSD-95) is a synaptic protein regulating glutamate receptor anchoring, synaptic stability and certain types of memory. Employing a loss-of-function mutant mouse lacking the guanylate kinase domain of PSD-95 (PSD-95GK), we analyzed the contribution of PSD-95 to fear memory formation and retrieval, and sought to identify the neural basis of PSD-95-mediated memory maintenance using ex vivo immediate-early gene mapping, in vivo neuronal recordings and viral-mediated knockdown approaches. We show that PSD-95 is dispensable for the formation and expression of recent fear memories, but essential for the formation of precise and flexible fear memories and for the maintenance of memories at remote time points. The failure of PSD-95GK mice to retrieve remote cued fear memories was associated with hypoactivation of the infralimbic cortex (IL) (not anterior cingulate (ACC) or prelimbic cortex), reduced IL single-unit firing and bursting, and attenuated IL gamma and theta oscillations. Adeno-associated PSD-95 virus-mediated knockdown in the IL, not ACC, was sufficient to impair recent fear extinction and remote fear memory, and remodel IL dendritic spines. Collectively, these data identify PSD-95 in the IL as a critical mechanism supporting the durability of fear memories over time. These preclinical findings have implications for developing novel approaches to treating trauma-based anxiety disorders that target the weakening of overly persistent fear memories. PMID:25510511

  4. Durable fear memories require PSD-95.

    PubMed

    Fitzgerald, P J; Pinard, C R; Camp, M C; Feyder, M; Sah, A; Bergstrom, H C; Graybeal, C; Liu, Y; Schlüter, O M; Grant, S G; Singewald, N; Xu, W; Holmes, A

    2015-07-01

    Traumatic fear memories are highly durable but also dynamic, undergoing repeated reactivation and rehearsal over time. Although overly persistent fear memories underlie anxiety disorders, such as posttraumatic stress disorder, the key neural and molecular mechanisms underlying fear memory durability remain unclear. Postsynaptic density 95 (PSD-95) is a synaptic protein regulating glutamate receptor anchoring, synaptic stability and certain types of memory. Using a loss-of-function mutant mouse lacking the guanylate kinase domain of PSD-95 (PSD-95(GK)), we analyzed the contribution of PSD-95 to fear memory formation and retrieval, and sought to identify the neural basis of PSD-95-mediated memory maintenance using ex vivo immediate-early gene mapping, in vivo neuronal recordings and viral-mediated knockdown (KD) approaches. We show that PSD-95 is dispensable for the formation and expression of recent fear memories, but essential for the formation of precise and flexible fear memories and for the maintenance of memories at remote time points. The failure of PSD-95(GK) mice to retrieve remote cued fear memory was associated with hypoactivation of the infralimbic (IL) cortex (but not the anterior cingulate cortex (ACC) or prelimbic cortex), reduced IL single-unit firing and bursting, and attenuated IL gamma and theta oscillations. Adeno-associated virus-mediated PSD-95 KD in the IL, but not the ACC, was sufficient to impair recent fear extinction and remote fear memory, and remodel IL dendritic spines. Collectively, these data identify PSD-95 in the IL as a critical mechanism supporting the durability of fear memories over time. These preclinical findings have implications for developing novel approaches to treating trauma-based anxiety disorders that target the weakening of overly persistent fear memories.

  5. Marine aggregate dynamics

    NASA Astrophysics Data System (ADS)

    The direction and scope of the Office of Naval Research's Marine Aggregate Dynamics Accelerated Research Initiative will be the topic of an open-house style meeting February 14, 7:30-10:00 P.M. in Ballroom D of the Hyatt Regency New Orleans at the Louisiana Superdome. This meeting is scheduled during the AGU/American Society of Limnology and Oceanography Ocean Sciences Meeting February 12-16 in New Orleans.The critical focus of the ARI is the measurement and modeling of the dynamics of the biological, physical, chemical and molecular processes that drive aggregation and produce aggregates. This new ARI will provide funding in Fiscal Years 1991-1995 to identify and quantify mechanisms that determine the distribution, abundance and size spectrum of aggregated particulate matter in the ocean.

  6. Protein Colloidal Aggregation Project

    NASA Technical Reports Server (NTRS)

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    To investigate the pathways and kinetics of protein aggregation to allow accurate predictive modeling of the process and evaluation of potential inhibitors to prevalent diseases including cataract formation, chronic traumatic encephalopathy, Alzheimer's Disease, Parkinson's Disease and others.

  7. Aggregation and Averaging.

    ERIC Educational Resources Information Center

    Siegel, Irving H.

    The arithmetic processes of aggregation and averaging are basic to quantitative investigations of employment, unemployment, and related concepts. In explaining these concepts, this report stresses need for accuracy and consistency in measurements, and describes tools for analyzing alternative measures. (BH)

  8. Reducing Router Forwarding Table Size Using Aggregation and Caching

    ERIC Educational Resources Information Center

    Liu, Yaoqing

    2013-01-01

    The fast growth of global routing table size has been causing concerns that the Forwarding Information Base (FIB) will not be able to fit in existing routers' expensive line-card memory, and upgrades will lead to a higher cost for network operators and customers. FIB Aggregation, a technique that merges multiple FIB entries into one, is probably…

  9. Memory Matters

    MedlinePlus

    ... blood vessel (which carries the blood) bursts. continue Brain Injuries Affect Memory At any age, an injury to ... with somebody's memory. Some people who recover from brain injuries need to learn old things all over again, ...

  10. Fibronectin Aggregation and Assembly

    PubMed Central

    Ohashi, Tomoo; Erickson, Harold P.

    2011-01-01

    The mechanism of fibronectin (FN) assembly and the self-association sites are still unclear and contradictory, although the N-terminal 70-kDa region (I1–9) is commonly accepted as one of the assembly sites. We previously found that I1–9 binds to superfibronectin, which is an artificial FN aggregate induced by anastellin. In the present study, we found that I1–9 bound to the aggregate formed by anastellin and a small FN fragment, III1–2. An engineered disulfide bond in III2, which stabilizes folding, inhibited aggregation, but a disulfide bond in III1 did not. A gelatin precipitation assay showed that I1–9 did not interact with anastellin, III1, III2, III1–2, or several III1–2 mutants including III1–2KADA. (In contrast to previous studies, we found that the III1–2KADA mutant was identical in conformation to wild-type III1–2.) Because I1–9 only bound to the aggregate and the unfolding of III2 played a role in aggregation, we generated a III2 domain that was destabilized by deletion of the G strand. This mutant bound I1–9 as shown by the gelatin precipitation assay and fluorescence resonance energy transfer analysis, and it inhibited FN matrix assembly when added to cell culture. Next, we introduced disulfide mutations into full-length FN. Three disulfide locks in III2, III3, and III11 were required to dramatically reduce anastellin-induced aggregation. When we tested the disulfide mutants in cell culture, only the disulfide bond in III2 reduced the FN matrix. These results suggest that the unfolding of III2 is one of the key factors for FN aggregation and assembly. PMID:21949131

  11. Memory Dysfunction

    PubMed Central

    Matthews, Brandy R.

    2015-01-01

    Purpose of Review: This article highlights the dissociable human memory systems of episodic, semantic, and procedural memory in the context of neurologic illnesses known to adversely affect specific neuroanatomic structures relevant to each memory system. Recent Findings: Advances in functional neuroimaging and refinement of neuropsychological and bedside assessment tools continue to support a model of multiple memory systems that are distinct yet complementary and to support the potential for one system to be engaged as a compensatory strategy when a counterpart system fails. Summary: Episodic memory, the ability to recall personal episodes, is the subtype of memory most often perceived as dysfunctional by patients and informants. Medial temporal lobe structures, especially the hippocampal formation and associated cortical and subcortical structures, are most often associated with episodic memory loss. Episodic memory dysfunction may present acutely, as in concussion; transiently, as in transient global amnesia (TGA); subacutely, as in thiamine deficiency; or chronically, as in Alzheimer disease. Semantic memory refers to acquired knowledge about the world. Anterior and inferior temporal lobe structures are most often associated with semantic memory loss. The semantic variant of primary progressive aphasia (svPPA) is the paradigmatic disorder resulting in predominant semantic memory dysfunction. Working memory, associated with frontal lobe function, is the active maintenance of information in the mind that can be potentially manipulated to complete goal-directed tasks. Procedural memory, the ability to learn skills that become automatic, involves the basal ganglia, cerebellum, and supplementary motor cortex. Parkinson disease and related disorders result in procedural memory deficits. Most memory concerns warrant bedside cognitive or neuropsychological evaluation and neuroimaging to assess for specific neuropathologies and guide treatment. PMID:26039844

  12. Memory protection

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1988-01-01

    Accidental overwriting of files or of memory regions belonging to other programs, browsing of personal files by superusers, Trojan horses, and viruses are examples of breakdowns in workstations and personal computers that would be significantly reduced by memory protection. Memory protection is the capability of an operating system and supporting hardware to delimit segments of memory, to control whether segments can be read from or written into, and to confine accesses of a program to its segments alone. The absence of memory protection in many operating systems today is the result of a bias toward a narrow definition of performance as maximum instruction-execution rate. A broader definition, including the time to get the job done, makes clear that cost of recovery from memory interference errors reduces expected performance. The mechanisms of memory protection are well understood, powerful, efficient, and elegant. They add to performance in the broad sense without reducing instruction execution rate.

  13. Smart Cards and remote entrusting

    NASA Astrophysics Data System (ADS)

    Aussel, Jean-Daniel; D'Annoville, Jerome; Castillo, Laurent; Durand, Stephane; Fabre, Thierry; Lu, Karen; Ali, Asad

    Smart cards are widely used to provide security in end-to-end communication involving servers and a variety of terminals, including mobile handsets or payment terminals. Sometime, end-to-end server to smart card security is not applicable, and smart cards must communicate directly with an application executing on a terminal, like a personal computer, without communicating with a server. In this case, the smart card must somehow trust the terminal application before performing some secure operation it was designed for. This paper presents a novel method to remotely trust a terminal application from the smart card. For terminals such as personal computers, this method is based on an advanced secure device connected through the USB and consisting of a smart card bundled with flash memory. This device, or USB dongle, can be used in the context of remote untrusting to secure portable applications conveyed in the dongle flash memory. White-box cryptography is used to set the secure channel and a mechanism based on thumbprint is described to provide external authentication when session keys need to be renewed. Although not as secure as end-to-end server to smart card security, remote entrusting with smart cards is easy to deploy for mass-market applications and can provide a reasonable level of security.

  14. Technology meets aggregate

    SciTech Connect

    Wilson, C.; Swan, C.

    2007-07-01

    New technology carried out at Tufts University and the University of Massachusetts on synthetic lightweight aggregate has created material from various qualities of fly ash from coal-fired power plants for use in different engineered applications. In pilot scale manufacturing tests an 'SLA' containing 80% fly ash and 20% mixed plastic waste from packaging was produced by 'dry blending' mixed plastic with high carbon fly ash. A trial run was completed to produce concrete masonry unit (CMU) blocks at a full-scale facility. It has been shown that SLA can be used as a partial substitution of a traditional stone aggregate in hot asphalt mix. 1 fig., 2 photos.

  15. Aggregates, broccoli and cauliflower

    NASA Astrophysics Data System (ADS)

    Grey, Francois; Kjems, Jørgen K.

    1989-09-01

    Naturally grown structures with fractal characters like broccoli and cauliflower are discussed and compared with DLA-type aggregates. It is suggested that the branching density can be used to characterize the growth process and an experimental method to determine this parameter is proposed.

  16. Flashbulb Memories

    PubMed Central

    Hirst, William; Phelps, Elizabeth A.

    2015-01-01

    We review and analyze the key theories, debates, findings, and omissions of the existing literature on flashbulb memories (FBMs), including what factors affect their formation, retention, and degree of confidence. We argue that FBMs do not require special memory mechanisms and are best characterized as involving both forgetting and mnemonic distortions, despite a high level of confidence. Factual memories for FBM-inducing events generally follow a similar pattern. Although no necessary and sufficient factors straightforwardly account for FBM retention, media attention particularly shapes memory for the events themselves. FBMs are best characterized in term of repetitions, even of mnemonic distortions, whereas event memories evidence corrections. The bearing of this literature on social identity and traumatic memories is also discussed. PMID:26997762

  17. Study of performance on SMP and distributed memory architectures using a shared memory programming model

    SciTech Connect

    Brooks, E.D.; Warren, K.H.

    1997-08-08

    In this paper we examine the use of a shared memory programming model to address the problem of portability of application codes between distributed memory and shared memory architectures. We do this with an extension of the Parallel C Preprocessor. The extension, borrowed from Split-C and AC, uses type qualifiers instead of storage class modifiers to declare variables that are shared among processors. The type qualifier declaration supports an abstract shared memory facility on distributed memory machines while making direct use of hardware support on shared memory architectures. Our benchmarking study spans a wide range of shared memory and distributed memory platforms. Benchmarks include Gaussian elimination with back substitution, a two-dimensional fast Fourier transform, and a matrix-matrix multiply. We find that the type-qualifier-based shared memory programming model is capable of efficiently spanning both distributed memory and shared memory architectures. Although the resulting shared memory programming model is portable, it does not remove the need to arrange for overlapped or blocked remote memory references on platforms that require these tuning measures in order to obtain good performance.

  18. Virtual memory

    NASA Technical Reports Server (NTRS)

    Denning, P. J.

    1986-01-01

    Virtual memory was conceived as a way to automate overlaying of program segments. Modern computers have very large main memories, but need automatic solutions to the relocation and protection problems. Virtual memory serves this need as well and is thus useful in computers of all sizes. The history of the idea is traced, showing how it has become a widespread, little noticed feature of computers today.

  19. Skilled Memory.

    DTIC Science & Technology

    1980-11-06

    Morse code (Bryan & Harter , 1899). In every case, memory performance of the expert seems to violate the established limits of short- term memory. How is...of immediate memory. Quarterly Journal of Experimental psychology, 1958, 10, 12-21. Bryan, W. L., & Harter N. psychological Review, 1899, 6, 345-375...16, 1980 Page 5 Civil Govt Non Govt Dr. Susan Chipman 1 Dr. John R. Anderson Learning and Development Department of Psychology National Institute of

  20. Tracking protein aggregate interactions

    PubMed Central

    Bartz, Jason C; Nilsson, K Peter R

    2011-01-01

    Amyloid fibrils share a structural motif consisting of highly ordered β-sheets aligned perpendicular to the fibril axis.1, 2 At each fibril end, β-sheets provide a template for recruiting and converting monomers.3 Different amyloid fibrils often co-occur in the same individual, yet whether a protein aggregate aids or inhibits the assembly of a heterologous protein is unclear. In prion disease, diverse prion aggregate structures, known as strains, are thought to be the basis of disparate disease phenotypes in the same species expressing identical prion protein sequences.4–7 Here we explore the interactions reported to occur when two distinct prion strains occur together in the central nervous system. PMID:21597336

  1. Zooplankton Aggregations Near Sills

    DTIC Science & Technology

    2003-09-30

    frequency echo-sounder system. This data were supplemented with multi-net (BIONESS) trawls, bongo nets, and otter trawls (operated by D. Mackas and group...side. The general composition of the zooplankton aggregations can be deduced from the relative levels of the three echo-sounder frequencies; krill ...Nov. 20th, 2002. Krill layer is evident at 66 – 90 m, coincident with BIONESS trawl through the region. 3 Figure 2 shows a comparison between

  2. Proteins aggregation and human diseases

    NASA Astrophysics Data System (ADS)

    Hu, Chin-Kun

    2015-04-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  3. Entanglement of distinguishable quantum memories

    NASA Astrophysics Data System (ADS)

    Vittorini, G.; Hucul, D.; Inlek, I. V.; Crocker, C.; Monroe, C.

    2014-10-01

    Time-resolved photon detection can be used to generate entanglement between distinguishable photons. This technique can be extended to entangle quantum memories that emit photons with different frequencies and identical temporal profiles without the loss of entanglement rate or fidelity. We experimentally realize this process using remotely trapped 171Yb+ ions where heralded entanglement is generated by interfering distinguishable photons. This technique may be necessary for future modular quantum systems and networks that are composed of heterogeneous qubits.

  4. Episodic Memories

    ERIC Educational Resources Information Center

    Conway, Martin A.

    2009-01-01

    An account of episodic memories is developed that focuses on the types of knowledge they represent, their properties, and the functions they might serve. It is proposed that episodic memories consist of "episodic elements," summary records of experience often in the form of visual images, associated to a "conceptual frame" that provides a…

  5. Collaging Memories

    ERIC Educational Resources Information Center

    Wallach, Michele

    2011-01-01

    Even middle school students can have memories of their childhoods, of an earlier time. The art of Romare Bearden and the writings of Paul Auster can be used to introduce ideas about time and memory to students and inspire works of their own. Bearden is an exceptional role model for young artists, not only because of his astounding art, but also…

  6. Multiple node remote messaging

    DOEpatents

    Blumrich, Matthias A.; Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Ohmacht, Martin; Salapura, Valentina; Steinmacher-Burow, Burkhard; Vranas, Pavlos

    2010-08-31

    A method for passing remote messages in a parallel computer system formed as a network of interconnected compute nodes includes that a first compute node (A) sends a single remote message to a remote second compute node (B) in order to control the remote second compute node (B) to send at least one remote message. The method includes various steps including controlling a DMA engine at first compute node (A) to prepare the single remote message to include a first message descriptor and at least one remote message descriptor for controlling the remote second compute node (B) to send at least one remote message, including putting the first message descriptor into an injection FIFO at the first compute node (A) and sending the single remote message and the at least one remote message descriptor to the second compute node (B).

  7. Memory conformity affects inaccurate memories more than accurate memories.

    PubMed

    Wright, Daniel B; Villalba, Daniella K

    2012-01-01

    After controlling for initial confidence, inaccurate memories were shown to be more easily distorted than accurate memories. In two experiments groups of participants viewed 50 stimuli and were then presented with these stimuli plus 50 fillers. During this test phase participants reported their confidence that each stimulus was originally shown. This was followed by computer-generated responses from a bogus participant. After being exposed to this response participants again rated the confidence of their memory. The computer-generated responses systematically distorted participants' responses. Memory distortion depended on initial memory confidence, with uncertain memories being more malleable than confident memories. This effect was moderated by whether the participant's memory was initially accurate or inaccurate. Inaccurate memories were more malleable than accurate memories. The data were consistent with a model describing two types of memory (i.e., recollective and non-recollective memories), which differ in how susceptible these memories are to memory distortion.

  8. Propagation Limitations in Remote Sensing.

    DTIC Science & Technology

    Contents: Multi-sensors and systems in remote sensing ; Radar sensing systems over land; Remote sensing techniques in oceanography; Influence of...propagation media and background; Infrared techniques in remote sensing ; Photography in remote sensing ; Analytical studies in remote sensing .

  9. Consolidation of Long-Term Memory: Evidence and Alternatives

    ERIC Educational Resources Information Center

    Meeter, Martijn; Murre, Jaap M. J.

    2004-01-01

    Memory loss in retrograde amnesia has long been held to be larger for recent periods than for remote periods, a pattern usually referred to as the Ribot gradient. One explanation for this gradient is consolidation of long-term memories. Several computational models of such a process have shown how consolidation can explain characteristics of…

  10. [Thematic Issue: Remote Sensing.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1978-01-01

    Four of the articles in this publication discuss the remote sensing of the Earth and its resources by satellites. Among the topics dealt with are the development and management of remote sensing systems, types of satellites used for remote sensing, the uses of remote sensing, and issues involved in using information obtained through remote…

  11. The influence of erythrocyte aggregation on induced platelet aggregation.

    PubMed

    Ott, C; Lardi, E; Schulzki, T; Reinhart, W H

    2010-01-01

    Red blood cells (RBCs) affect platelet aggregation in flowing blood (primary hemostasis). We tested the hypothesis that RBC aggregation could influence platelet aggregation. RBC aggregation was altered in vitro by: (i) changing plasma aggregatory properties with 3.7 g% dextran 40 (D40), 3.0 g% dextran 70 (D70) or 1.55 g% dextran 500 (D500); (ii) changing RBC aggregatory properties by incubating RBCs in 50 mU/ml neuraminidase for 60 min (reduction of the surface sialic acid content, thus reducing electrostatic repulsion) and subsequent RBC resuspension in platelet rich plasma (PRP) containing 1 g% dextran 70. RBC aggregation was assessed with the sedimentation rate (ESR). Platelet aggregation was measured: (i) in flowing whole blood with a platelet function analyzer PFA-100(R), which simulates in vivo conditions with RBCs flowing in the center and platelets along the wall, where they adhere to collagen and aggregate; and (ii) in a Chrono-log 700 Aggregometer, which measures changes of impedance by platelet aggregation in whole blood or changes in light transmission in PRP. We found that RBC aggregation increased with increasing molecular weight of dextran (ESR: 4 +/- 3 mm/h, 34 +/- 14 mm/h and 89 +/- 23 mm/hfor D40, D70 and D500, respectively, p < 0.0001) and with neuraminidase-treated RBCs (76 +/- 27 mm/h vs 27 +/- 8 mm/h, respectively, p < 0.0001). Platelet aggregation measured in whole blood under flow conditions (PFA-100) and without flow (Chronolog Aggregometer) was not affected by RBC aggregation. Our data suggest that RBC aggregation does not affect platelet aggregation in vitro and plays no role in primary hemostasis.

  12. Innate immune memory in plants.

    PubMed

    Reimer-Michalski, Eva-Maria; Conrath, Uwe

    2016-08-01

    The plant innate immune system comprises local and systemic immune responses. Systemic plant immunity develops after foliar infection by microbial pathogens, upon root colonization by certain microbes, or in response to physical injury. The systemic plant immune response to localized foliar infection is associated with elevated levels of pattern-recognition receptors, accumulation of dormant signaling enzymes, and alterations in chromatin state. Together, these systemic responses provide a memory to the initial infection by priming the remote leaves for enhanced defense and immunity to reinfection. The plant innate immune system thus builds immunological memory by utilizing mechanisms and components that are similar to those employed in the trained innate immune response of jawed vertebrates. Therefore, there seems to be conservation, or convergence, in the evolution of innate immune memory in plants and vertebrates.

  13. Structure of Viral Aggregates

    NASA Astrophysics Data System (ADS)

    Barr, Stephen; Luijten, Erik

    2010-03-01

    The aggregation of virus particles is a particular form of colloidal self-assembly, since viruses of a give type are monodisperse and have identical, anisotropic surface charge distributions. In small-angle X-ray scattering experiments, the Qbeta virus was found to organize in different crystal structures in the presence of divalent salt and non-adsorbing polymer. Since a simple isotropic potential cannot explain the occurrence of all observed phases, we employ computer simulations to investigate how the surface charge distribution affects the virus interactions. Using a detailed model of the virus particle, we find an asymmetric ion distribution around the virus which gives rise to the different phases observed.

  14. Programming distributed memory architectures using Kali

    NASA Technical Reports Server (NTRS)

    Mehrotra, Piyush; Vanrosendale, John

    1990-01-01

    Programming nonshared memory systems is more difficult than programming shared memory systems, in part because of the relatively low level of current programming environments for such machines. A new programming environment is presented, Kali, which provides a global name space and allows direct access to remote data values. In order to retain efficiency, Kali provides a system on annotations, allowing the user to control those aspects of the program critical to performance, such as data distribution and load balancing. The primitives and constructs provided by the language is described, and some of the issues raised in translating a Kali program for execution on distributed memory systems are also discussed.

  15. A Brighter Side to Memory Illusions: False Memories Prime Children's and Adults' Insight-Based Problem Solving

    ERIC Educational Resources Information Center

    Howe, Mark L.; Garner, Sarah R.; Charlesworth, Monica; Knott, Lauren

    2011-01-01

    Can false memories have a positive consequence on human cognition? In two experiments, we investigated whether false memories could prime insight problem-solving tasks. Children and adults were asked to solve compound remote associate task (CRAT) problems, half of which had been primed by the presentation of Deese/Roediger-McDermott (DRM) lists…

  16. Memory loss

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003257.htm Memory loss To use the sharing features on this ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  17. Engagement of the PFC in Consolidation and Recall of Recent Spatial Memory

    ERIC Educational Resources Information Center

    Leon, Wanda C.; Bruno, Martin A.; Allard, Simon; Nader, Karim; Cuello, A. Claudio

    2010-01-01

    The standard model of system consolidation proposes that memories are initially hippocampus dependent and become hippocampus independent over time. Previous studies have demonstrated the involvement of the medial prefrontal cortex (mPFC) in the retrieval of remote memories. The transformations required to make a memory undergo system's…

  18. Connecting Spatial Memories of Two Nested Spaces

    ERIC Educational Resources Information Center

    Zhang, Hui; Mou, Weimin; McNamara, Timothy P.; Wang, Lin

    2014-01-01

    Four experiments investigated the manner in which people use spatial reference directions to organize spatial memories of 2 conceptually nested layouts. Participants learned directions of 8 remote cities centered to Beijing or Edmonton, where the experiments occurred, using a map or using direct pointing. The map and the environment were aligned,…

  19. Holographic characterization of protein aggregates

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Zhong, Xiao; Ruffner, David; Stutt, Alexandra; Philips, Laura; Ward, Michael; Grier, David

    Holographic characterization directly measures the size distribution of subvisible protein aggregates in suspension and offers insights into their morphology. Based on holographic video microscopy, this analytical technique records and interprets holograms of individual aggregates in protein solutions as they flow down a microfluidic channel, without requiring labeling or other exceptional sample preparation. The hologram of an individual protein aggregate is analyzed in real time with the Lorenz-Mie theory of light scattering to measure that aggregate's size and optical properties. Detecting, counting and characterizing subvisible aggregates proceeds fast enough for time-resolved studies, and lends itself to tracking trends in protein aggregation arising from changing environmental factors. No other analytical technique provides such a wealth of particle-resolved characterization data in situ. Holographic characterization promises accelerated development of therapeutic protein formulations, improved process control during manufacturing, and streamlined quality assurance during storage and at the point of use. Mrsec and MRI program of the NSF, Spheryx Inc.

  20. Folding, Binding, Misfolding and Aggregation with AWSEM

    NASA Astrophysics Data System (ADS)

    Schafer, Nicholas P.

    This thesis discusses our recent results using the Associative-memory, Water-mediated, Structure and Energy Model (AWSEM), an optimized, coarse-grained molecular dynamics protein folding model, to fold, bind, and predict the misfolding behavior of proteins. AWSEM is capable of performing de novo structure prediction on small alpha-helical protein domains and predict the binding interfaces of homo- and hetero-dimers. More recent work demonstrates how the misfolding behavior of tandem constructs in AWSEM is consistent with crucial aspects of ensemble and single molecule experiments on the aggregation and misfolding of these constructs. The first chapter is a review of the energy landscape theory of protein folding as it applies to the problem of protein structure prediction, and more specifically how energy landscape theory and the principle of minimal frustration can be used to optimize parameters of coarse-grained protein folding simulation models. The subsequent four chapters are reports of novel research performed with one such model.

  1. Aggregating local image descriptors into compact codes.

    PubMed

    Jégou, Hervé; Perronnin, Florent; Douze, Matthijs; Sánchez, Jorge; Pérez, Patrick; Schmid, Cordelia

    2012-09-01

    This paper addresses the problem of large-scale image search. Three constraints have to be taken into account: search accuracy, efficiency, and memory usage. We first present and evaluate different ways of aggregating local image descriptors into a vector and show that the Fisher kernel achieves better performance than the reference bag-of-visual words approach for any given vector dimension. We then jointly optimize dimensionality reduction and indexing in order to obtain a precise vector comparison as well as a compact representation. The evaluation shows that the image representation can be reduced to a few dozen bytes while preserving high accuracy. Searching a 100 million image data set takes about 250 ms on one processor core.

  2. Fractal structure of asphaltene aggregates.

    PubMed

    Rahmani, Nazmul H G; Dabros, Tadeusz; Masliyah, Jacob H

    2005-05-15

    A photographic technique coupled with image analysis was used to measure the size and fractal dimension of asphaltene aggregates formed in toluene-heptane solvent mixtures. First, asphaltene aggregates were examined in a Couette device and the fractal-like aggregate structures were quantified using boundary fractal dimension. The evolution of the floc structure with time was monitored. The relative rates of shear-induced aggregation and fragmentation/restructuring determine the steady-state floc structure. The average floc structure became more compact or more organized as the floc size distribution attained steady state. Moreover, the higher the shear rate is, the more compact the floc structure is at steady state. Second, the fractal dimensions of asphaltene aggregates were also determined in a free-settling test. The experimentally determined terminal settling velocities and characteristic lengths of the aggregates were utilized to estimate the 2D and 3D fractal dimensions. The size-density fractal dimension (D(3)) of the asphaltene aggregates was estimated to be in the range from 1.06 to 1.41. This relatively low fractal dimension suggests that the asphaltene aggregates are highly porous and very tenuous. The aggregates have a structure with extremely low space-filling capacity.

  3. Aggregation dynamics of rigid polyelectrolytes

    NASA Astrophysics Data System (ADS)

    Tom, Anvy Moly; Rajesh, R.; Vemparala, Satyavani

    2016-01-01

    Similarly charged polyelectrolytes are known to attract each other and aggregate into bundles when the charge density of the polymers exceeds a critical value that depends on the valency of the counterions. The dynamics of aggregation of such rigid polyelectrolytes are studied using large scale molecular dynamics simulations. We find that the morphology of the aggregates depends on the value of the charge density of the polymers. For values close to the critical value, the shape of the aggregates is cylindrical with height equal to the length of a single polyelectrolyte chain. However, for larger values of charge, the linear extent of the aggregates increases as more and more polymers aggregate. In both the cases, we show that the number of aggregates decrease with time as power laws with exponents that are not numerically distinguishable from each other and are independent of charge density of the polymers, valency of the counterions, density, and length of the polyelectrolyte chain. We model the aggregation dynamics using the Smoluchowski coagulation equation with kernels determined from the molecular dynamics simulations and justify the numerically obtained value of the exponent. Our results suggest that once counterions condense, effective interactions between polyelectrolyte chains short-ranged and the aggregation of polyelectrolytes are diffusion-limited.

  4. Fear Memory.

    PubMed

    Izquierdo, Ivan; Furini, Cristiane R G; Myskiw, Jociane C

    2016-04-01

    Fear memory is the best-studied form of memory. It was thoroughly investigated in the past 60 years mostly using two classical conditioning procedures (contextual fear conditioning and fear conditioning to a tone) and one instrumental procedure (one-trial inhibitory avoidance). Fear memory is formed in the hippocampus (contextual conditioning and inhibitory avoidance), in the basolateral amygdala (inhibitory avoidance), and in the lateral amygdala (conditioning to a tone). The circuitry involves, in addition, the pre- and infralimbic ventromedial prefrontal cortex, the central amygdala subnuclei, and the dentate gyrus. Fear learning models, notably inhibitory avoidance, have also been very useful for the analysis of the biochemical mechanisms of memory consolidation as a whole. These studies have capitalized on in vitro observations on long-term potentiation and other kinds of plasticity. The effect of a very large number of drugs on fear learning has been intensively studied, often as a prelude to the investigation of effects on anxiety. The extinction of fear learning involves to an extent a reversal of the flow of information in the mentioned structures and is used in the therapy of posttraumatic stress disorder and fear memories in general.

  5. Aggregate resource availability in the conterminous United States, including suggestions for addressing shortages, quality, and environmental concerns

    USGS Publications Warehouse

    Langer, William H.

    2011-01-01

    Although potential sources of aggregate are widespread throughout the United States, many sources may not meet certain physical property requirements, such as soundness, hardness, strength, porosity, and specific gravity, or they may contain contaminants or deleterious materials that render them unusable. Encroachment by conflicting land uses, permitting considerations, environmental issues, and societal pressures can prevent or limit development of otherwise suitable aggregate. The use of sustainable aggregate resource management can help ensure an economically viable supply of aggregate. Sustainable aggregate resource management techniques that have successfully been used include (1) protecting potential resources from encroachment; (2) using marginal-quality local aggregate for applications that do not demand a high-quality resource; (3) using substitute materials such as clinker, scoria, and recycled asphalt and concrete; and (4) using rail and water to transport aggregates from remote sources.

  6. Tropospheric Passive Remote Sensing

    NASA Technical Reports Server (NTRS)

    Keafer, L. S., Jr. (Editor)

    1982-01-01

    The long term role of airborne/spaceborne passive remote sensing systems for tropospheric air quality research and the identification of technology advances required to improve the performance of passive remote sensing systems were discussed.

  7. Topics in Probabilistic Judgment Aggregation

    ERIC Educational Resources Information Center

    Wang, Guanchun

    2011-01-01

    This dissertation is a compilation of several studies that are united by their relevance to probabilistic judgment aggregation. In the face of complex and uncertain events, panels of judges are frequently consulted to provide probabilistic forecasts, and aggregation of such estimates in groups often yield better results than could have been made…

  8. Mineral of the month: aggregates

    USGS Publications Warehouse

    Tepordei, Valentin V.

    2005-01-01

    Natural aggregates, consisting of crushed stone, and sand and gravel, are a major contributor to economic health, and have an amazing variety of uses. Aggregates are among the most abundant mineral resources and are major basic raw materials used by construction, agriculture and other industries that employ complex chemical and metallurgical processes.

  9. Principles for problem aggregation and assignment in medium scale multiprocessors

    NASA Technical Reports Server (NTRS)

    Nicol, David M.; Saltz, Joel H.

    1987-01-01

    One of the most important issues in parallel processing is the mapping of workload to processors. This paper considers a large class of problems having a high degree of potential fine grained parallelism, and execution requirements that are either not predictable, or are too costly to predict. The main issues in mapping such a problem onto medium scale multiprocessors are those of aggregation and assignment. We study a method of parameterized aggregation that makes few assumptions about the workload. The mapping of aggregate units of work onto processors is uniform, and exploits locality of workload intensity to balance the unknown workload. In general, a finer aggregate granularity leads to a better balance at the price of increased communication/synchronization costs; the aggregation parameters can be adjusted to find a reasonable granularity. The effectiveness of this scheme is demonstrated on three model problems: an adaptive one-dimensional fluid dynamics problem with message passing, a sparse triangular linear system solver on both a shared memory and a message-passing machine, and a two-dimensional time-driven battlefield simulation employing message passing. Using the model problems, the tradeoffs are studied between balanced workload and the communication/synchronization costs. Finally, an analytical model is used to explain why the method balances workload and minimizes the variance in system behavior.

  10. Aggregate dust particles at comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Bentley, Mark S.; Schmied, Roland; Mannel, Thurid; Torkar, Klaus; Jeszenszky, Harald; Romstedt, Jens; Levasseur-Regourd, Anny-Chantal; Weber, Iris; Jessberger, Elmar K.; Ehrenfreund, Pascale; Koeberl, Christian; Havnes, Ove

    2016-09-01

    Comets are thought to preserve almost pristine dust particles, thus providing a unique sample of the properties of the early solar nebula. The microscopic properties of this dust played a key part in particle aggregation during the formation of the Solar System. Cometary dust was previously considered to comprise irregular, fluffy agglomerates on the basis of interpretations of remote observations in the visible and infrared and the study of chondritic porous interplanetary dust particles that were thought, but not proved, to originate in comets. Although the dust returned by an earlier mission has provided detailed mineralogy of particles from comet 81P/Wild, the fine-grained aggregate component was strongly modified during collection. Here we report in situ measurements of dust particles at comet 67P/Churyumov-Gerasimenko. The particles are aggregates of smaller, elongated grains, with structures at distinct sizes indicating hierarchical aggregation. Topographic images of selected dust particles with sizes of one micrometre to a few tens of micrometres show a variety of morphologies, including compact single grains and large porous aggregate particles, similar to chondritic porous interplanetary dust particles. The measured grain elongations are similar to the value inferred for interstellar dust and support the idea that such grains could represent a fraction of the building blocks of comets. In the subsequent growth phase, hierarchical agglomeration could be a dominant process and would produce aggregates that stick more easily at higher masses and velocities than homogeneous dust particles. The presence of hierarchical dust aggregates in the near-surface of the nucleus of comet 67P also provides a mechanism for lowering the tensile strength of the dust layer and aiding dust release.

  11. Aggregate dust particles at comet 67P/Churyumov-Gerasimenko.

    PubMed

    Bentley, Mark S; Schmied, Roland; Mannel, Thurid; Torkar, Klaus; Jeszenszky, Harald; Romstedt, Jens; Levasseur-Regourd, Anny-Chantal; Weber, Iris; Jessberger, Elmar K; Ehrenfreund, Pascale; Koeberl, Christian; Havnes, Ove

    2016-09-01

    Comets are thought to preserve almost pristine dust particles, thus providing a unique sample of the properties of the early solar nebula. The microscopic properties of this dust played a key part in particle aggregation during the formation of the Solar System. Cometary dust was previously considered to comprise irregular, fluffy agglomerates on the basis of interpretations of remote observations in the visible and infrared and the study of chondritic porous interplanetary dust particles that were thought, but not proved, to originate in comets. Although the dust returned by an earlier mission has provided detailed mineralogy of particles from comet 81P/Wild, the fine-grained aggregate component was strongly modified during collection. Here we report in situ measurements of dust particles at comet 67P/Churyumov-Gerasimenko. The particles are aggregates of smaller, elongated grains, with structures at distinct sizes indicating hierarchical aggregation. Topographic images of selected dust particles with sizes of one micrometre to a few tens of micrometres show a variety of morphologies, including compact single grains and large porous aggregate particles, similar to chondritic porous interplanetary dust particles. The measured grain elongations are similar to the value inferred for interstellar dust and support the idea that such grains could represent a fraction of the building blocks of comets. In the subsequent growth phase, hierarchical agglomeration could be a dominant process and would produce aggregates that stick more easily at higher masses and velocities than homogeneous dust particles. The presence of hierarchical dust aggregates in the near-surface of the nucleus of comet 67P also provides a mechanism for lowering the tensile strength of the dust layer and aiding dust release.

  12. Molecular aggregation of humic substances

    USGS Publications Warehouse

    Wershaw, R. L.

    1999-01-01

    Humic substances (HS) form molecular aggregates in solution and on mineral surfaces. Elucidation of the mechanism of formation of these aggregates is important for an understanding of the interactions of HS in soils arid natural waters. The HS are formed mainly by enzymatic depolymerization and oxidation of plant biopolymers. These reactions transform the aromatic and lipid plant components into amphiphilic molecules, that is, molecules that consist of separate hydrophobic (nonpolar) and hydrophilic (polar) parts. The nonpolar parts of the molecules are composed of relatively unaltered segments of plant polymers and the polar parts of carboxylic acid groups. These amphiphiles form membrane-like aggregates on mineral surfaces and micelle-like aggregates in solution. The exterior surfaces of these aggregates are hydrophilic, and the interiors constitute separate hydrophobic liquid-like phases.

  13. Premature red blood cells have decreased aggregation and enhanced aggregability.

    PubMed

    Arbell, D; Orkin, B; Bar-Oz, B; Barshtein, G; Yedgar, S

    2008-06-01

    Preterm infants are highly susceptible to ischemic damage. This damage is most obvious in the brain, retina, and gastrointestinal tract. Studies focusing on the rheological properties of premature red blood cells (pRBCs) have consistently shown minimal or no RBC aggregation. Previously, measurements of pRBC aggregation kinetics indicated that specific plasma properties are responsible for the decreased RBC aggregation observed in the neonates, but that their specific RBC properties do not affect it. However, the strength of interaction in the pRBC aggregates as a function of medium composition has not been tested. In our previous research, we described clinically relevant parameters, that is, the aggregate resistance to disaggregation by flow. With the help of a cell flow property analyzer (CFA), we can monitor RBC aggregation by direct visualization of its dynamics during flow. We used the CFA to examine pRBC (from 9 premature babies) in the natural plasma and in PBS buffer supplemented with dextran (500 kDa) to distinguish between RBC intrinsic-cellular and plasma factors. pRBCs suspended in the native plasma showed minimal or no aggregation in comparison to normal adult RBC. When we transferred pRBCs from the same sample to the dextran solution, enhanced resistance to disaggregation by flow was apparent.

  14. Orthogonal flexible Rydberg aggregates

    NASA Astrophysics Data System (ADS)

    Leonhardt, K.; Wüster, S.; Rost, J. M.

    2016-02-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.

  15. Engrams and circuits crucial for systems consolidation of a memory.

    PubMed

    Kitamura, Takashi; Ogawa, Sachie K; Roy, Dheeraj S; Okuyama, Teruhiro; Morrissey, Mark D; Smith, Lillian M; Redondo, Roger L; Tonegawa, Susumu

    2017-04-07

    Episodic memories initially require rapid synaptic plasticity within the hippocampus for their formation and are gradually consolidated in neocortical networks for permanent storage. However, the engrams and circuits that support neocortical memory consolidation have thus far been unknown. We found that neocortical prefrontal memory engram cells, which are critical for remote contextual fear memory, were rapidly generated during initial learning through inputs from both the hippocampal-entorhinal cortex network and the basolateral amygdala. After their generation, the prefrontal engram cells, with support from hippocampal memory engram cells, became functionally mature with time. Whereas hippocampal engram cells gradually became silent with time, engram cells in the basolateral amygdala, which were necessary for fear memory, were maintained. Our data provide new insights into the functional reorganization of engrams and circuits underlying systems consolidation of memory.

  16. Fueling Memories

    PubMed Central

    Powell, Jonathan D.; Pollizzi, Kristen

    2012-01-01

    A hallmark of the adaptive immune response is rapid and robust activation upon rechallenge. In the current issue of Immunity van der Windt et al. (2012) provide an important link between mitochondrial respiratory capacity and the development of CD8+ T cell memory. PMID:22284413

  17. Childhood Memories.

    ERIC Educational Resources Information Center

    Soto, Lourdes Diaz

    2001-01-01

    Describes how artwork can be a valuable catalyst for discussions in preservice education classes, allowing students to explore how their work as educators relates to their childhood memories and can be shaped by childhood experiences. Examines an art exhibition in which diverse artists depicted autobiographical text in their paintings. Discusses…

  18. Retracing Memories

    ERIC Educational Resources Information Center

    Harrison, David L.

    2005-01-01

    There are plenty of paths to poetry but few are as accessible as retracing ones own memories. When students are asked to write about something they remember, they are given them the gift of choosing from events that are important enough to recall. They remember because what happened was funny or scary or embarrassing or heartbreaking or silly.…

  19. Hollow memories

    NASA Astrophysics Data System (ADS)

    2014-04-01

    A hollow-core optical fibre filled with warm caesium atoms can temporarily store the properties of photons. Michael Sprague from the University of Oxford, UK, explains to Nature Photonics how this optical memory could be a useful building block for fibre-based quantum optics.

  20. Remotely Monitored Sealing Array Software

    SciTech Connect

    2012-09-12

    The Remotely Monitored Sealing Array (RMSA) utilizes the Secure Sensor Platform (SSP) framework to establish the fundamental operating capabilities for communication, security, power management, and cryptography. In addition to the SSP framework the RMSA software has unique capabilities to support monitoring a fiber optic seal. Fiber monitoring includes open and closed as well as parametric monitoring to detect tampering attacks. The fiber monitoring techniques, using the SSP power management processes, allow the seals to last for years while maintaining the security requirements of the monitoring application. The seal is enclosed in a tamper resistant housing with software to support active tamper monitoring. New features include LED notification of fiber closure, the ability to retrieve the entire fiber optic history via translator command, separate memory storage for fiber optic events, and a more robust method for tracking and resending failed messages.

  1. Kinetics of Aggregation with Choice

    DOE PAGES

    Ben-Naim, Eli; Krapivsky, Paul

    2016-12-01

    Here we generalize the ordinary aggregation process to allow for choice. In ordinary aggregation, two random clusters merge and form a larger aggregate. In our implementation of choice, a target cluster and two candidate clusters are randomly selected and the target cluster merges with the larger of the two candidate clusters.We study the long-time asymptotic behavior and find that as in ordinary aggregation, the size density adheres to the standard scaling form. However, aggregation with choice exhibits a number of different features. First, the density of the smallest clusters exhibits anomalous scaling. Second, both the small-size and the large-size tailsmore » of the density are overpopulated, at the expense of the density of moderate-size clusters. Finally, we also study the complementary case where the smaller candidate cluster participates in the aggregation process and find an abundance of moderate clusters at the expense of small and large clusters. Additionally, we investigate aggregation processes with choice among multiple candidate clusters and a symmetric implementation where the choice is between two pairs of clusters.« less

  2. Kinetics of Aggregation with Choice

    SciTech Connect

    Ben-Naim, Eli; Krapivsky, Paul

    2016-12-01

    Here we generalize the ordinary aggregation process to allow for choice. In ordinary aggregation, two random clusters merge and form a larger aggregate. In our implementation of choice, a target cluster and two candidate clusters are randomly selected and the target cluster merges with the larger of the two candidate clusters.We study the long-time asymptotic behavior and find that as in ordinary aggregation, the size density adheres to the standard scaling form. However, aggregation with choice exhibits a number of different features. First, the density of the smallest clusters exhibits anomalous scaling. Second, both the small-size and the large-size tails of the density are overpopulated, at the expense of the density of moderate-size clusters. Finally, we also study the complementary case where the smaller candidate cluster participates in the aggregation process and find an abundance of moderate clusters at the expense of small and large clusters. Additionally, we investigate aggregation processes with choice among multiple candidate clusters and a symmetric implementation where the choice is between two pairs of clusters.

  3. Practical applications of remote sensing technology

    NASA Technical Reports Server (NTRS)

    Whitmore, Roy A., Jr.

    1990-01-01

    Land managers increasingly are becoming dependent upon remote sensing and automated analysis techniques for information gathering and synthesis. Remote sensing and geographic information system (GIS) techniques provide quick and economical information gathering for large areas. The outputs of remote sensing classification and analysis are most effective when combined with a total natural resources data base within the capabilities of a computerized GIS. Some examples are presented of the successes, as well as the problems, in integrating remote sensing and geographic information systems. The need to exploit remotely sensed data and the potential that geographic information systems offer for managing and analyzing such data continues to grow. New microcomputers with vastly enlarged memory, multi-fold increases in operating speed and storage capacity that was previously available only on mainframe computers are a reality. Improved raster GIS software systems have been developed for these high performance microcomputers. Vector GIS systems previously reserved for mini and mainframe systems are available to operate on these enhanced microcomputers. One of the more exciting areas that is beginning to emerge is the integration of both raster and vector formats on a single computer screen. This technology will allow satellite imagery or digital aerial photography to be presented as a background to a vector display.

  4. Fractal aggregates in Titan's atmosphere

    NASA Astrophysics Data System (ADS)

    Cabane, M.; Rannou, P.; Chassefiere, E.; Israel, G.

    1993-04-01

    The cluster structure of Titan's atmosphere was modeled by using an Eulerian microphysical model with the specific formulation of microphysical laws applying to fractal particles. The growth of aggregates in the settling phase was treated by introducing the fractal dimension as a parameter of the model. The model was used to obtain a vertical distribution of size and number density of the aggregates for different production altitudes. Results confirm previous estimates of the formation altitude of photochemical aerosols. The vertical profile of the effective radius of aggregates was calculated as a function of the visible optical depth.

  5. Dorsal medial prefrontal cortex contributes to conditioned taste aversion memory consolidation and retrieval.

    PubMed

    Gonzalez, Maria Carolina; Villar, Maria Eugenia; Igaz, Lionel M; Viola, Haydée; Medina, Jorge H

    2015-12-01

    The medial prefrontal cortex (mPFC) is known for its role in decision making and memory processing, including the participation in the formation of extinction memories. However, little is known regarding its contribution to aversive memory consolidation. Here we demonstrate that neural activity and protein synthesis are required in the dorsal mPFC for memory formation of a conditioned taste aversion (CTA) task and that this region is involved in the retrieval of recent and remote long-term CTA memory. In addition, both NMDA receptor and CaMKII activity in dorsal mPFC are needed for CTA memory consolidation, highlighting the complexity of mPFC functions.

  6. Surface fractals in liposome aggregation.

    PubMed

    Roldán-Vargas, Sándalo; Barnadas-Rodríguez, Ramon; Quesada-Pérez, Manuel; Estelrich, Joan; Callejas-Fernández, José

    2009-01-01

    In this work, the aggregation of charged liposomes induced by magnesium is investigated. Static and dynamic light scattering, Fourier-transform infrared spectroscopy, and cryotransmission electron microscopy are used as experimental techniques. In particular, multiple intracluster scattering is reduced to a negligible amount using a cross-correlation light scattering scheme. The analysis of the cluster structure, probed by means of static light scattering, reveals an evolution from surface fractals to mass fractals with increasing magnesium concentration. Cryotransmission electron microscopy micrographs of the aggregates are consistent with this interpretation. In addition, a comparative analysis of these results with those previously reported in the presence of calcium suggests that the different hydration energy between lipid vesicles when these divalent cations are present plays a fundamental role in the cluster morphology. This suggestion is also supported by infrared spectroscopy data. The kinetics of the aggregation processes is also analyzed through the time evolution of the mean diffusion coefficient of the aggregates.

  7. Cell aggregation: Packing soft grains

    NASA Astrophysics Data System (ADS)

    Åström, J. A.; Karttunen, M.

    2006-06-01

    Cellular aggregates may be considered as collections of membrane enclosed units with a pressure difference between the internal and external liquid phases. Cells are kept together by membrane adhesion and/or confined space compression. Pattern formation and, in particular, intercellular spacing have important roles in controlling solvent diffusion within such aggregates. A physical approach is used to study generic aspects of cellular packings in a confined space. Average material properties are derived from the free energy. The appearance of penetrating intercellular void channels is found to be critically governed by the cell wall adhesion mechanisms during the formation of dense aggregates. A fully relaxed aggregate efficiently hinders solvent diffusion at high hydrostatic pressures, while a small fraction (˜0.1) of adhesion related packing frustration is sufficient for breaking such a blockage even at high a pressure.

  8. Aggregate breakdown of nanoparticulate titania

    NASA Astrophysics Data System (ADS)

    Venugopal, Navin

    Six nanosized titanium dioxide powders synthesized from a sulfate process were investigated. The targeted end-use of this powder was for a de-NOx catalyst honeycomb monolith. Alteration of synthesis parameters had resulted principally in differences in soluble ion level and specific surface area of the powders. The goal of this investigation was to understand the role of synthesis parameters in the aggregation behavior of these powders. Investigation via scanning electron microscopy of the powders revealed three different aggregation iterations at specific length scales. Secondary and higher order aggregate strength was investigated via oscillatory stress rheometry as a means of simulating shear conditions encountered during extrusion. G' and G'' were measured as a function of the applied oscillatory stress. Oscillatory rheometry indicated a strong variation as a function of the sulfate level of the particles in the viscoelastic yield strengths. Powder yield stresses ranged from 3.0 Pa to 24.0 Pa of oscillatory stress. Compaction curves to 750 MPa found strong similarities in extrapolated yield point of stage I and II compaction for each of the powders (at approximately 500 MPa) suggesting that the variation in sulfate was greatest above the primary aggregate level. Scanning electron microscopy of samples at different states of shear in oscillatory rheometry confirmed the variation in the linear elastic region and the viscous flow regime. A technique of this investigation was to approach aggregation via a novel perspective: aggregates are distinguished as being loose open structures that are highly disordered and stochastic in nature. The methodology used was to investigate the shear stresses required to rupture the various aggregation stages encountered and investigate the attempt to realign the now free-flowing constituents comprising the aggregate into a denser configuration. Mercury porosimetry was utilized to measure the pore size of the compact resulting from

  9. Glycation precedes lens crystallin aggregation

    SciTech Connect

    Swamy, M.S.; Perry, R.E.; Abraham, E.C.

    1987-05-01

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both (/sup 3/H)NaBH/sub 4/ reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated.

  10. Model for amorphous aggregation processes

    NASA Astrophysics Data System (ADS)

    Stranks, Samuel D.; Ecroyd, Heath; van Sluyter, Steven; Waters, Elizabeth J.; Carver, John A.; von Smekal, Lorenz

    2009-11-01

    The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first applications of the model, we have tested it against experimental turbidimetry data of three proteins relevant to the wine industry and biochemistry, namely, thaumatin, a thaumatinlike protein, and α -lactalbumin. The model is very robust and describes amorphous experimental data to a high degree of accuracy. Details about the aggregation process, such as shape parameters of the aggregates and rate constants, can also be extracted.

  11. Robust hippocampal responsivity during retrieval of consolidated associative memory

    PubMed Central

    Hattori, Shoai; Chen, Lillian; Weiss, Craig

    2015-01-01

    ABSTRACT A contentious point in memory research is whether or not the hippocampus plays a time‐limited role in the consolidation of declarative memories. A widely held view is that declarative memories are initially encoded in the hippocampus, then transferred to the neocortex for long‐term storage. Alternate views argue instead that the hippocampus continues to play a role in remote memory recall. These competing theories are largely based on human amnesic and animal lesion/inactivation studies. However, in vivo electrophysiological evidence supporting these views is scarce. Given that other studies examining the role of the hippocampus in remote memory retrieval using lesion and imaging techniques in human and animal models have provided mixed results, it would be particularly useful to gain insight at the in vivo electrophysiological level. Here we report hippocampal single‐neuron and theta activity recorded longitudinally during acquisition and remote retrieval of trace eyeblink conditioning. Results from conditioned rabbits were compared to those obtained from yoked pseudo‐conditioned control rabbits. Results reveal continued learning‐specific hippocampal activity one month after initial acquisition of the task. Our findings yield insight into the normal physiological responses of the hippocampus during memory processes and provide compelling in vivo electrophysiological evidence that the hippocampus is involved in both acquisition and retrieval of consolidated memories. © 2014 The Authors Hippocampus Published by Wiley Periodicals, Inc. PMID:25515308

  12. Ash Aggregates in Proximal Settings

    NASA Astrophysics Data System (ADS)

    Porritt, L. A.; Russell, K.

    2012-12-01

    Ash aggregates are thought to have formed within and been deposited by the eruption column and plume and dilute density currents and their associated ash clouds. Moist, turbulent ash clouds are considered critical to ash aggregate formation by facilitating both collision and adhesion of particles. Consequently, they are most commonly found in distal deposits. Proximal deposits containing ash aggregates are less commonly observed but do occur. Here we describe two occurrences of vent proximal ash aggregate-rich deposits; the first within a kimberlite pipe where coated ash pellets and accretionary lapilli are found within the intra-vent sequence; and the second in a glaciovolcanic setting where cored pellets (armoured lapilli) occur within <1 km of the vent. The deposits within the A418 pipe, Diavik Diamond Mine, Canada, are the residual deposits within the conduit and vent of the volcano and are characterised by an abundance of ash aggregates. Coated ash pellets are dominant but are followed in abundance by ash pellets, accretionary lapilli and rare cored pellets. The coated ash pellets typically range from 1 - 5 mm in diameter and have core to rim ratios of approximately 10:1. The formation and preservation of these aggregates elucidates the style and nature of the explosive phase of kimberlite eruption at A418 (and other pipes?). First, these pyroclasts dictate the intensity of the kimberlite eruption; it must be energetic enough to cause intense fragmentation of the kimberlite to produce a substantial volume of very fine ash (<62 μm). Secondly, the ash aggregates indicate the involvement of moisture coupled with the presence of dilute expanded eruption clouds. The structure and distribution of these deposits throughout the kimberlite conduit demand that aggregation and deposition operate entirely within the confines of the vent; this indicates that aggregation is a rapid process. Ash aggregates within glaciovolcanic sequences are also rarely documented. The

  13. Labile aggregation stimulating substance, free fatty acids, and platelet aggregation.

    PubMed

    Gerrard, J M; White, J G; Krivit, W

    1976-01-01

    Labile aggregation stimulating substance (LASS), an intermediate produced during platelet biosynthesis of PGE2 and PGF2alpha, acts as a physiologic intercellular messenger to promote platelet aggregation and the release reaction. The activity is formed by intact cells after physiologic stimulation or can be generated from platelet membrane fractions after combination with arachidonate. In the present investigation, small amounts of polyunsaturated fatty acids added to an incubation mixture of platelet microsomes and arachidonate were found to significantly inhibit subsequent platelet aggregation. Saturated and mono-unsaturated fatty acids in the same concentrations were without effect. However, in higher concentrations mono-unsaturated fatty acids were found to be inhibitory and stearic acid was found to enhance subsequent platelet aggregation. The inhibition caused by the polyunsaturated fatty acid, linoleate, was shown to be the result of an effect on the production of LASS through an interaction with the platelet enzyme responsible for conversion of arachidonate to LASS. In contrast, stearic acid was found to enhance platelet aggregation by acting on the platelets and not directly on LASS production. The results suggest that small changes in the fatty acid composition of platelet phospholipids could significantly influence platelet reactivity.

  14. REMOTE SENSING IN OCEANOGRAPHY.

    DTIC Science & Technology

    remote sensing from satellites. Sensing of oceanographic variables from aircraft began with the photographing of waves and ice. Since then remote measurement of sea surface temperatures and wave heights have become routine. Sensors tested for oceanographic applications include multi-band color cameras, radar scatterometers, infrared spectrometers and scanners, passive microwave radiometers, and radar imagers. Remote sensing has found its greatest application in providing rapid coverage of large oceanographic areas for synoptic and analysis and

  15. Remote reset circuit

    DOEpatents

    Gritzo, Russell E.

    1987-01-01

    A remote reset circuit acts as a stand-alone monitor and controller by clocking in each character sent by a terminal to a computer and comparing it to a given reference character. When a match occurs, the remote reset circuit activates the system's hardware reset line. The remote reset circuit is hardware based centered around monostable multivibrators and is unaffected by system crashes, partial serial transmissions, or power supply transients.

  16. Aggregation propensity of critical regions of the protein Tau

    NASA Astrophysics Data System (ADS)

    Muthee, Micaiah; Ahmed, Azka; Larini, Luca

    The Alzheimer's disease is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills, which eventually leads to the ability to not able to carry out the simplest tasks. The Alzheimer's disease is characterized by the formation of protein aggregates both within and outside of the brain's cells, the neurons. Within the neurons, the aggregation of the protein tau leads to the destruction of the microtubules in the axon of the neuron. Tau belongs to a group of proteins referred to as Microtubule-Associated Proteins. It is extremely flexible and is classified as an intrinsically unstructured protein due to its low propensity to form secondary structure. Tau promotes tubulin assembly into microtubules thereby stabilizing the cytoskeleton of the axon of the neurons. The microtubule binding region of tau consists of 4 pseudo-repeats. In this study, we will focus on the aggregation propensity of two fragments. In this study we will focus on the PHF43 fragment that contains the third pseudo-repeat and has been shown experimentally to aggregate readily. Another fragment that contains the second pseudo-repeat will be considered as well. Mutations in this region are associated with various form of dementia and for this reason we will consider the mutant P301L.

  17. Advanced Remote Sensing Research

    USGS Publications Warehouse

    Slonecker, Terrence; Jones, John W.; Price, Susan D.; Hogan, Dianna

    2008-01-01

    'Remote sensing' is a generic term for monitoring techniques that collect information without being in physical contact with the object of study. Overhead imagery from aircraft and satellite sensors provides the most common form of remotely sensed data and records the interaction of electromagnetic energy (usually visible light) with matter, such as the Earth's surface. Remotely sensed data are fundamental to geographic science. The Eastern Geographic Science Center (EGSC) of the U.S. Geological Survey (USGS) is currently conducting and promoting the research and development of three different aspects of remote sensing science: spectral analysis, automated orthorectification of historical imagery, and long wave infrared (LWIR) polarimetric imagery (PI).

  18. Remote measurement of pollution

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A summary of the major conclusions and recommendations developed by the panels on gaseous air pollution, water pollution, and particulate air pollution is presented. It becomes evident that many of the trace gases are amenable to remote sensing; that certain water pollutants can be measured by remote techniques, but their number is limited; and that a similar approach to the remote measurement of specific particulate pollutants will follow only after understanding of their physical, chemical, and radiative properties is improved. It is also clear that remote sensing can provide essential information in all three categories that can not be obtained by any other means.

  19. Remote Systems Design & Deployment

    SciTech Connect

    Bailey, Sharon A.; Baker, Carl P.; Valdez, Patrick LJ

    2009-08-28

    The Pacific Northwest National Laboratory (PNNL) was tasked by Washington River Protection Solutions, LLC (WRPS) to provide information and lessons learned relating to the design, development and deployment of remote systems, particularly remote arm/manipulator systems. This report reflects PNNL’s experience with remote systems and lays out the most important activities that need to be completed to successfully design, build, deploy and operate remote systems in radioactive and chemically contaminated environments. It also contains lessons learned from PNNL’s work experiences, and the work of others in the national laboratory complex.

  20. Fractal Aggregates in Tennis Ball Systems

    ERIC Educational Resources Information Center

    Sabin, J.; Bandin, M.; Prieto, G.; Sarmiento, F.

    2009-01-01

    We present a new practical exercise to explain the mechanisms of aggregation of some colloids which are otherwise not easy to understand. We have used tennis balls to simulate, in a visual way, the aggregation of colloids under reaction-limited colloid aggregation (RLCA) and diffusion-limited colloid aggregation (DLCA) regimes. We have used the…

  1. Gaussian multiscale aggregation applied to segmentation in hand biometrics.

    PubMed

    de Santos Sierra, Alberto; Avila, Carmen Sánchez; Casanova, Javier Guerra; del Pozo, Gonzalo Bailador

    2011-01-01

    This paper presents an image segmentation algorithm based on Gaussian multiscale aggregation oriented to hand biometric applications. The method is able to isolate the hand from a wide variety of background textures such as carpets, fabric, glass, grass, soil or stones. The evaluation was carried out by using a publicly available synthetic database with 408,000 hand images in different backgrounds, comparing the performance in terms of accuracy and computational cost to two competitive segmentation methods existing in literature, namely Lossy Data Compression (LDC) and Normalized Cuts (NCuts). The results highlight that the proposed method outperforms current competitive segmentation methods with regard to computational cost, time performance, accuracy and memory usage.

  2. In vitro evidence that an aqueous extract of Centella asiatica modulates α-synuclein aggregation dynamics.

    PubMed

    Berrocal, Ruben; Vasudevaraju, Padmaraju; Indi, Shantinath Satappa; Sambasiva Rao, Krothapalli Raja Surya; Rao, K S

    2014-01-01

    α-Synuclein aggregation is one of the major etiological factors implicated in Parkinson's disease (PD). The prevention of aggregation of α-synuclein is a potential therapeutic intervention for preventing PD. The discovery of natural products as alternative drugs to treat PD and related disorders is a current trend. The aqueous extract of Centella asiatica (CA) is traditionally used as a brain tonic and CA is known to improve cognition and memory. There are limited data on the role of CA in modulating amyloid-β (Aβ) levels in the brain and in Aβ aggregation. Our study focuses on CA as a modulator of the α-synuclein aggregation pattern in vitro. Our investigation is focused on: (i) whether the CA leaf aqueous extract prevents the formation of aggregates from monomers (Phase I: α-synuclein + extract co-incubation); (ii) whether the CA aqueous extract prevents the formation of fibrils from oligomers (Phase II: extract added after oligomers formation); and (iii) whether the CA aqueous extract disintegrates the pre-formed fibrils (Phase III: extract added to mature fibrils and incubated for 9 days). The aggregation kinetics are studied using a thioflavin-T assay, circular dichroism, and transmission electron microscopy. The results showed that the CA aqueous extract completely inhibited the α-synuclein aggregation from monomers. Further, CA extract significantly inhibited the formation of oligomer to aggregates and favored the disintegration of the preformed fibrils. The study provides an insight in finding new natural products for future PD therapeutics.

  3. Thermodynamic modeling of asphaltene aggregation.

    PubMed

    Rogel, E

    2004-02-03

    A new molecular thermodynamic model for the description of the aggregation behavior of asphaltenes in different solvents is presented. This new model is relatively simple and strictly predictive and does not use any experimental information from asphaltene solutions. In this model, asphaltene aggregates are described as composed of an aromatic core formed by stacked aromatic sheets surrounded by aliphatic chains. The proposed model qualitatively predicts the asphaltene aggregation behavior in a series of different solvents. In particular, the experimental trends observed for the variation of aggregate size with (1) asphaltene molecular characteristics (condensation index, aromaticity, and chain length), (2) asphaltene concentration, (3) solvent characteristics, and (4) temperature have been successfully reproduced by the proposed model. The model also provides a plausible explanation for the existence or absence of a critical micelle concentration (cmc) for asphaltene solutions. Specifically, the model predicted that the asphaltenes with low aromaticities and low aromatic condensations do not exhibit cmc behavior. Finally, the obtained results clearly support the classical model for asphaltene aggregates.

  4. Spatial aggregation: Language and applications

    SciTech Connect

    Bailey-Kellogg, C.; Zhao, F.; Yip, K.

    1996-12-31

    Spatial aggregation is a framework for organizing computations around image-like, analogue representations of physical processes in data interpretation and control tasks. It conceptualizes common computational structures in a class of implemented problem solvers for difficult scientific and engineering problems. It comprises a mechanism, a language, and a programming style. The spatial aggregation mechanism transforms a numerical input field to successively higher-level descriptions by applying a small, identical set of operators to each layer given a metric, neighborhood relation and equivalence relation. This paper describes the spatial aggregation language and its applications. The spatial aggregation language provides two abstract data types - neighborhood graph and field - and a set of interface operators for constructing the transformations of the field, together with a library of component implementations from which a user can mix-and-match and specialize for a particular application. The language allows users to isolate and express important computational ideas in different problem domains while hiding low-level details. We illustrate the use of the language with examples ranging from trajectory grouping in dynamics interpretation to region growing in image analysis. Programs for these different task domains can be written in a modular, concise fashion in the spatial aggregation language.

  5. Leaching behaviour of synthetic aggregates.

    PubMed

    van der Sloot, H A; Hoede, D; Cresswell, D J; Barton, J R

    2001-01-01

    In the framework of EU project "Utilising innovative kiln technology to recycle waste into synthetic aggregate" (BRST-CT98-5234), the leaching behaviour of synthetic aggregates has been studied to assess its environmental compatibility in the various stages of its use. Since the conditions are very different for the different uses, the assessment calls for a variety of different leaching conditions. The pH dependence test is used to cover important differences in pH environment to which the materials are exposed to as well as for an assessment of the buffering capacity of the material. Synthetic aggregate features a low buffer capacity, which makes it sensitive to externally imposed pH conditions. Utilisation and storage exposed to acidic conditions needs to be avoided. The results of the pH dependence test and column leaching test are mutually consistent. The CEN TC 154 method appears to provide systematically low values due to the arbitrary selection of test conditions. Synthetic aggregate studied to date will not adversely affect the concrete in its service life. The main issue for aggregate use is the recycling and the "end of life" condition, when the material becomes construction debris. Not metals, but oxyanions, such as Cr VI and Mo are most relevant under these conditions. A concise test has been applied to assess crucial aspects of leaching for different production mixes.

  6. Novel insights into amylin aggregation

    PubMed Central

    Pillay, Karen; Govender, Patrick

    2014-01-01

    Amylin is a peptide that aggregates into species that are toxic to pancreatic beta cells, leading to type II diabetes. This study has for the first time quantified amylin association and dissociation kinetics (association constant (ka) = 28.7 ± 5.1 L mol−1 s−1 and dissociation constant (kd) = 2.8 ± 0.6 ×10−4 s−1) using surface plasmon resonance (SPR). Thus far, techniques used for the sizing of amylin aggregates do not cater for the real-time monitoring of unconstrained amylin in solution. In this regard we evaluated recently innovated nanoparticle tracking analysis (NTA). In addition, both SPR and NTA were used to study the effect of previously synthesized amylin derivatives on amylin aggregation and to evaluate their potential as a cell-free system for screening potential inhibitors of amylin-mediated cytotoxicity. Results obtained from NTA highlighted a predominance of 100–300 nm amylin aggregates and correlation to previously published cytotoxicity results suggests the toxic species of amylin to be 200–300 nm in size. The results seem to indicate that NTA has potential as a new technique to monitor the aggregation potential of amyloid peptides in solution and also to screen potential inhibitors of amylin-mediated cytotoxicity. PMID:26019498

  7. Aggregated Recommendation through Random Forests

    PubMed Central

    2014-01-01

    Aggregated recommendation refers to the process of suggesting one kind of items to a group of users. Compared to user-oriented or item-oriented approaches, it is more general and, therefore, more appropriate for cold-start recommendation. In this paper, we propose a random forest approach to create aggregated recommender systems. The approach is used to predict the rating of a group of users to a kind of items. In the preprocessing stage, we merge user, item, and rating information to construct an aggregated decision table, where rating information serves as the decision attribute. We also model the data conversion process corresponding to the new user, new item, and both new problems. In the training stage, a forest is built for the aggregated training set, where each leaf is assigned a distribution of discrete rating. In the testing stage, we present four predicting approaches to compute evaluation values based on the distribution of each tree. Experiments results on the well-known MovieLens dataset show that the aggregated approach maintains an acceptable level of accuracy. PMID:25180204

  8. Customer Aggregation: An Opportunity for Green Power?

    SciTech Connect

    Holt, E.; Bird, L.

    2001-02-26

    We undertook research into the experience of aggregation groups to determine whether customer aggregation offers an opportunity to bring green power choices to more customers. The objectives of this report, therefore, are to (1) identify the different types of aggregation that are occurring today, (2) learn whether aggregation offers an opportunity to advance sales of green power, and (3) share these concepts and approaches with potential aggregators and green power advocates.

  9. Remote sensing applications program

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The activities of the Mississippi Remote Sensing Center are described in addition to technology transfer and information dissemination, remote sensing topics such as timber identification, water quality, flood prevention, land use, erosion control, animal habitats, and environmental impact studies are also discussed.

  10. APPLIED REMOTE SENSING

    EPA Science Inventory

    Remote Sensing is a scientific discipline of non-contact monitoring. It includes a range of technologies that span from aerial photography to advanced spectral imaging and analytical methods. This Session is designed to demonstrate contemporary practical applications of remote se...

  11. Remote actuated valve implant

    DOEpatents

    McKnight, Timothy E; Johnson, Anthony; Moise, Jr., Kenneth J; Ericson, Milton Nance; Baba, Justin S; Wilgen, John B; Evans, III, Boyd McCutchen

    2014-02-25

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  12. Demystifying Remote Access

    ERIC Educational Resources Information Center

    Howe, Grant

    2009-01-01

    With money tight, more and more districts are considering remote access as a way to reduce expenses and budget information technology costs more effectively. Remote access allows staff members to work with a hosted software application from any school campus without being tied to a specific physical location. Each school can access critical…

  13. Land Remote Sensing Overview

    NASA Technical Reports Server (NTRS)

    Byrnes, Ray

    2007-01-01

    A general overview of the USGS land remote sensing program is presented. The contents include: 1) Brief overview of USGS land remote sensing program; 2) Highlights of JACIE work at USGS; 3) Update on NASA/USGS Landsat Data Continuity Mission; and 4) Notes on alternative data sources.

  14. Equilibrium structure of ferrofluid aggregates.

    PubMed

    Yoon, Mina; Tománek, David

    2010-11-17

    We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a competition between various energy terms, which can be approximated analytically within a continuum model. We also study the effect of external parameters such as magnetic field on the relative stability of these structures. Our results may give insight into experimental data obtained during solidification of ferrofluid aggregates at temperatures where thermal fluctuations become negligible in comparison to inter-particle interactions. These data may also help to experimentally control the aggregation of magnetic particles.

  15. Equilibrium structure of ferrofluid aggregates

    SciTech Connect

    Yoon, Mina; Tomanek, David

    2010-01-01

    We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a competition between various energy terms, which can be approximated analytically within a continuum model. We also study the effect of external parameters such as magnetic field on the relative stability of these structures. Our results may give insight into experimental data obtained during solidification of ferrofluid aggregates at temperatures where thermal fluctuations become negligible in comparison to inter-particle interactions. These data may also help to experimentally control the aggregation of magnetic particles.

  16. Effects of aggregation on scattering and radiative properties of soot aerosols

    NASA Astrophysics Data System (ADS)

    Liu, Li; Mishchenko, Michael I.

    2005-06-01

    The superposition T-matrix method is used to compute the scattering matrix elements and optical cross sections for a wide variety of fractal-like soot aggregates in random orientation at a visible wavelength 0.628 μm. The effects of the fractal dimension and prefactor, the monomer radius, the number of monomers in the aggregate, and the refractive index on light scattering and absorption by aggregated soot particles are analyzed. It is shown that the configuration of the monomers can have a substantial effect and that aggregation can result in a significant enhancement of extinction and scattering relative to those computed from the Lorenz-Mie theory, assuming that there are no electromagnetic interactions between the monomers. Thus one must take the effects of soot agglomeration and cluster morphology into account in radiative transfer modeling and remote sensing applications.

  17. Remote sensing of wetlands

    NASA Technical Reports Server (NTRS)

    Roller, N. E. G.

    1977-01-01

    The concept of using remote sensing to inventory wetlands and the related topics of proper inventory design and data collection are discussed. The material presented shows that aerial photography is the form of remote sensing from which the greatest amount of wetlands information can be derived. For extensive, general-purpose wetlands inventories, however, the use of LANDSAT data may be more cost-effective. Airborne multispectral scanners and radar are, in the main, too expensive to use - unless the information that these sensors alone can gather remotely is absolutely required. Multistage sampling employing space and high altitude remote sensing data in the initial stages appears to be an efficient survey strategy for gathering non-point specific wetlands inventory data over large areas. The operational role of remote sensing insupplying inventory data for application to several typical wetlands management problems is illustrated by summary descriptions of past ERIM projects.

  18. A specialist's audit of aggregated occurrence records: An 'aggregator's' perspective.

    PubMed

    Belbin, Lee; Daly, Joanne; Hirsch, Tim; Hobern, Donald; Salle, John La

    2013-01-01

    A recent ZooKeys' paper (Mesibov, 2013: http://www.pensoft.net/journal_home_page.php?journal_id=1&page=article&SESID=df7bcb35b02603283dcb83ee0e0af0c9&type=show&article_id=5111) has highlighted data quality issues in aggregated data sets, but did not provide a realistic way to address these issues. This paper provides an aggregator's perspective including ways that the whole community can help to address data quality issues. The establishment of GBIF and national nodes (national aggregators) such as the Atlas of Living Australia (ALA) have integrated and exposed a huge diversity of biological observations along with many associated issues. Much of the admirable work by Mesibov (2013) was enabled by having the data exposed. Data quality, one of the highest priorities for GBIF, the national nodes and other aggregators, depends on both automatic methods and community experts to detect and correct data issues. Not all issues can however be automatically detected or corrected, so community assistance is needed to help improve the quality of exposed biological data. We do need to improve the infrastructure and associated processes to more easily identify data issues and document all changes to ensure a full record is permanently and publicly available.

  19. Environmentalism and natural aggregate mining

    USGS Publications Warehouse

    Drew, L.J.; Langer, W.H.; Sachs, J.S.

    2002-01-01

    Sustaining a developed economy and expanding a developing one require the use of large volumes of natural aggregate. Almost all human activity (commercial, recreational, or leisure) is transacted in or on facilities constructed from natural aggregate. In our urban and suburban worlds, we are almost totally dependent on supplies of water collected behind dams and transported through aqueducts made from concrete. Natural aggregate is essential to the facilities that produce energy-hydroelectric dams and coal-fired powerplants. Ironically, the utility created for mankind by the use of natural aggregate is rarely compared favorably with the environmental impacts of mining it. Instead, the empty quarries and pits are seen as large negative environmental consequences. At the root of this disassociation is the philosophy of environmentalism, which flavors our perceptions of the excavation, processing, and distribution of natural aggregate. The two end-member ideas in this philosophy are ecocentrism and anthropocentrism. Ecocentrism takes the position that the natural world is a organism whose arteries are the rivers-their flow must not be altered. The soil is another vital organ and must not be covered with concrete and asphalt. The motto of the ecocentrist is "man must live more lightly on the land." The anthropocentrist wants clean water and air and an uncluttered landscape for human use. Mining is allowed and even encouraged, but dust and noise from quarry and pit operations must be minimized. The large volume of truck traffic is viewed as a real menace to human life and should be regulated and isolated. The environmental problems that the producers of natural aggregate (crushed stone and sand and gravel) face today are mostly difficult social and political concerns associated with the large holes dug in the ground and the large volume of heavy truck traffic associated with quarry and pit operations. These concerns have increased in recent years as society's demand for

  20. Hydrodynamic behavior of fractal aggregates

    NASA Astrophysics Data System (ADS)

    Wiltzius, Pierre

    1987-02-01

    Measurements of the radius of gyration RG and the hydrodynamic radius RH of colloidal silica aggregates are reported. These aggregates have fractal geometry and RH is proportional to RG for 500 Å<=RH<=7000 Å, with a ratio RH/RG=0.72+/-0.02. The results are compared with predictions for macromolecules of various shapes. The proportionality of the two radii can be understood with use of the pair correlation function of fractal objects and hydrodynamic interactions on the Oseen level. The value of the ratio remains to be explained.

  1. A Beginner's Guide to Memory.

    ERIC Educational Resources Information Center

    Hughes, Elizabeth M.

    1981-01-01

    This article is designed to equip the reader with the information needed to deal with questions of computer memory. Discussed are core memory; semiconductor memory; size of memory; expanding memory; charge-coupled device memories; magnetic bubble memory; and read-only and read-mostly memories. (KC)

  2. Working memory and intelligibility of hearing-aid processed speech.

    PubMed

    Souza, Pamela E; Arehart, Kathryn H; Shen, Jing; Anderson, Melinda; Kates, James M

    2015-01-01

    Previous work suggested that individuals with low working memory capacity may be at a disadvantage in adverse listening environments, including situations with background noise or substantial modification of the acoustic signal. This study explored the relationship between patient factors (including working memory capacity) and intelligibility and quality of modified speech for older individuals with sensorineural hearing loss. The modification was created using a combination of hearing aid processing [wide-dynamic range compression (WDRC) and frequency compression (FC)] applied to sentences in multitalker babble. The extent of signal modification was quantified via an envelope fidelity index. We also explored the contribution of components of working memory by including measures of processing speed and executive function. We hypothesized that listeners with low working memory capacity would perform more poorly than those with high working memory capacity across all situations, and would also be differentially affected by high amounts of signal modification. Results showed a significant effect of working memory capacity for speech intelligibility, and an interaction between working memory, amount of hearing loss and signal modification. Signal modification was the major predictor of quality ratings. These data add to the literature on hearing-aid processing and working memory by suggesting that the working memory-intelligibility effects may be related to aggregate signal fidelity, rather than to the specific signal manipulation. They also suggest that for individuals with low working memory capacity, sensorineural loss may be most appropriately addressed with WDRC and/or FC parameters that maintain the fidelity of the signal envelope.

  3. Working memory and intelligibility of hearing-aid processed speech

    PubMed Central

    Souza, Pamela E.; Arehart, Kathryn H.; Shen, Jing; Anderson, Melinda; Kates, James M.

    2015-01-01

    Previous work suggested that individuals with low working memory capacity may be at a disadvantage in adverse listening environments, including situations with background noise or substantial modification of the acoustic signal. This study explored the relationship between patient factors (including working memory capacity) and intelligibility and quality of modified speech for older individuals with sensorineural hearing loss. The modification was created using a combination of hearing aid processing [wide-dynamic range compression (WDRC) and frequency compression (FC)] applied to sentences in multitalker babble. The extent of signal modification was quantified via an envelope fidelity index. We also explored the contribution of components of working memory by including measures of processing speed and executive function. We hypothesized that listeners with low working memory capacity would perform more poorly than those with high working memory capacity across all situations, and would also be differentially affected by high amounts of signal modification. Results showed a significant effect of working memory capacity for speech intelligibility, and an interaction between working memory, amount of hearing loss and signal modification. Signal modification was the major predictor of quality ratings. These data add to the literature on hearing-aid processing and working memory by suggesting that the working memory-intelligibility effects may be related to aggregate signal fidelity, rather than to the specific signal manipulation. They also suggest that for individuals with low working memory capacity, sensorineural loss may be most appropriately addressed with WDRC and/or FC parameters that maintain the fidelity of the signal envelope. PMID:25999874

  4. Memory Retrieval and Interference: Working Memory Issues

    ERIC Educational Resources Information Center

    Radvansky, Gabriel A.; Copeland, David E.

    2006-01-01

    Working memory capacity has been suggested as a factor that is involved in long-term memory retrieval, particularly when that retrieval involves a need to overcome some sort of interference (Bunting, Conway, & Heitz, 2004; Cantor & Engle, 1993). Previous work has suggested that working memory is related to the acquisition of information during…

  5. Optical memory

    DOEpatents

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  6. Studies on recycled aggregates-based concrete.

    PubMed

    Rakshvir, Major; Barai, Sudhirkumar V

    2006-06-01

    Reduced extraction of raw materials, reduced transportation cost, improved profits, reduced environmental impact and fast-depleting reserves of conventional natural aggregates has necessitated the use of recycling, in order to be able to conserve conventional natural aggregate. In this study various physical and mechanical properties of recycled concrete aggregates were examined. Recycled concrete aggregates are different from natural aggregates and concrete made from them has specific properties. The percentages of recycled concrete aggregates were varied and it was observed that properties such as compressive strength showed a decrease of up to 10% as the percentage of recycled concrete aggregates increased. Water absorption of recycled aggregates was found to be greater than natural aggregates, and this needs to be compensated during mix design.

  7. Mesoscale Simulation of Asphaltene Aggregation.

    PubMed

    Wang, Jiang; Ferguson, Andrew L

    2016-08-18

    Asphaltenes constitute a heavy aromatic crude oil fraction with a propensity to aggregate and precipitate out of solution during petroleum processing. Aggregation is thought to proceed according to the Yen-Mullins hierarchy, but the molecular mechanisms underlying mesoscopic assembly remain poorly understood. By combining coarse-grained molecular models parametrized using all-atom data with high-performance GPU hardware, we have performed molecular dynamics simulations of the aggregation of hundreds of asphaltenes over microsecond time scales. Our simulations reveal a hierarchical self-assembly mechanism consistent with the Yen-Mullins model, but the details are sensitive and depend on asphaltene chemistry and environment. At low concentrations asphaltenes exist predominantly as dispersed monomers. Upon increasing concentration, we first observe parallel stacking into 1D rod-like nanoaggregates, followed by the formation of clusters of nanoaggregates associated by offset, T-shaped, and edge-edge stacking. Asphaltenes possessing long aliphatic side chains cannot form nanoaggregate clusters due to steric repulsions between their aliphatic coronae. At very high concentrations, we observe a porous percolating network of rod-like nanoaggregates suspended in a sea of interpenetrating aliphatic side chains with a fractal dimension of ∼2. The lifetime of the rod-like aggregates is described by an exponential distribution reflecting a dynamic equilibrium between coagulation and fragmentation.

  8. RAGG - R EPISODIC AGGREGATION PACKAGE

    EPA Science Inventory

    The RAGG package is an R implementation of the CMAQ episodic model aggregation method developed by Constella Group and the Environmental Protection Agency. RAGG is a tool to provide climatological seasonal and annual deposition of sulphur and nitrogen for multimedia management. ...

  9. Sequence-dependent internalization of aggregating peptides.

    PubMed

    Couceiro, José R; Gallardo, Rodrigo; De Smet, Frederik; De Baets, Greet; Baatsen, Pieter; Annaert, Wim; Roose, Kenny; Saelens, Xavier; Schymkowitz, Joost; Rousseau, Frederic

    2015-01-02

    Recently, a number of aggregation disease polypeptides have been shown to spread from cell to cell, thereby displaying prionoid behavior. Studying aggregate internalization, however, is often hampered by the complex kinetics of the aggregation process, resulting in the concomitant uptake of aggregates of different sizes by competing mechanisms, which makes it difficult to isolate pathway-specific responses to aggregates. We designed synthetic aggregating peptides bearing different aggregation propensities with the aim of producing modes of uptake that are sufficiently distinct to differentially analyze the cellular response to internalization. We found that small acidic aggregates (≤500 nm in diameter) were taken up by nonspecific endocytosis as part of the fluid phase and traveled through the endosomal compartment to lysosomes. By contrast, bigger basic aggregates (>1 μm) were taken up through a mechanism dependent on cytoskeletal reorganization and membrane remodeling with the morphological hallmarks of phagocytosis. Importantly, the properties of these aggregates determined not only the mechanism of internalization but also the involvement of the proteostatic machinery (the assembly of interconnected networks that control the biogenesis, folding, trafficking, and degradation of proteins) in the process; whereas the internalization of small acidic aggregates is HSF1-independent, the uptake of larger basic aggregates was HSF1-dependent, requiring Hsp70. Our results show that the biophysical properties of aggregates determine both their mechanism of internalization and proteostatic response. It remains to be seen whether these differences in cellular response contribute to the particular role of specific aggregated proteins in disease.

  10. Order-memory and association-memory.

    PubMed

    Caplan, Jeremy B

    2015-09-01

    Two highly studied memory functions are memory for associations (items presented in pairs, such as SALT-PEPPER) and memory for order (a list of items whose order matters, such as a telephone number). Order- and association-memory are at the root of many forms of behaviour, from wayfinding, to language, to remembering people's names. Most researchers have investigated memory for order separately from memory for associations. Exceptions to this, associative-chaining models build an ordered list from associations between pairs of items, quite literally understanding association- and order-memory together. Alternatively, positional-coding models have been used to explain order-memory as a completely distinct function from association-memory. Both classes of model have found empirical support and both have faced serious challenges. I argue that models that combine both associative chaining and positional coding are needed. One such hybrid model, which relies on brain-activity rhythms, is promising, but remains to be tested rigourously. I consider two relatively understudied memory behaviours that demand a combination of order- and association-information: memory for the order of items within associations (is it William James or James William?) and judgments of relative order (who left the party earlier, Hermann or William?). Findings from these underexplored procedures are already difficult to reconcile with existing association-memory and order-memory models. Further work with such intermediate experimental paradigms has the potential to provide powerful findings to constrain and guide models into the future, with the aim of explaining a large range of memory functions, encompassing both association- and order-memory.

  11. Increased Task Demand during Spatial Memory Testing Recruits the Anterior Cingulate Cortex

    ERIC Educational Resources Information Center

    Carr, Joshua K.; Fournier, Neil M.; Lehmann, Hugo

    2016-01-01

    We examined whether increasing retrieval difficulty in a spatial memory task would promote the recruitment of the anterior cingulate cortex (ACC) similar to what is typically observed during remote memory retrieval. Rats were trained on the hidden platform version of the Morris Water Task and tested three or 30 d later. Retrieval difficulty was…

  12. Transient Relay Function of Midline Thalamic Nuclei during Long-Term Memory Consolidation in Humans

    ERIC Educational Resources Information Center

    Thielen, Jan-Willem; Takashima, Atsuko; Rutters, Femke; Tendolkar, Indira; Fernández, Guillén

    2015-01-01

    To test the hypothesis that thalamic midline nuclei play a transient role in memory consolidation, we reanalyzed a prospective functional MRI study, contrasting recent and progressively more remote memory retrieval. We revealed a transient thalamic connectivity increase with the hippocampus, the medial prefrontal cortex (mPFC), and a…

  13. When we feel good and bad about ourselves: self-esteem memories across cultures.

    PubMed

    Ivcevic, Zorana; Pillemer, David B; Wang, Qi; Hou, Yubo; Tang, Huizhen; Mohoric, Tamara; Taksic, Vladimir

    2008-10-01

    Young adults in the United States, Croatia, and China described personal episodes of times when they felt especially good or bad about themselves. These self-esteem memories were either recent (episodes that occurred during the previous 4 weeks) or remote (episodes that occurred between the ages of 10 and 15). Systematic content differences between memories of positive and negative self-worth were apparent primarily for remote rather than for recent memories. Across cultures, long-lasting positive memories frequently represented achievement themes, whereas negative memories frequently represented social themes. Links between achievement success and positive self-regard, and between social distress and negative self-regard, are explained using theories of self-esteem and autobiographical memory.

  14. Remote sensing program

    NASA Technical Reports Server (NTRS)

    Philipson, W. R. (Principal Investigator)

    1983-01-01

    Built on Cornell's thirty years of experience in aerial photographic studies, the NASA-sponsored remote sensing program strengthened instruction and research in remote sensing, established communication links within and beyond the university community, and conducted research projects for or with town, county, state, federal, and private organizations in New York State. The 43 completed applied research projects are listed as well as 13 spinoff grants/contracts. The curriculum offered, consultations provided, and data processing facilities available are described. Publications engendered are listed including the thesis of graduates in the remote sensing program.

  15. Remote Raman measurement techniques

    NASA Technical Reports Server (NTRS)

    Leonard, D. A.

    1981-01-01

    The use of laser Raman measurement techniques in remote sensing applications is surveyed. A feasibility index is defined as a means to characterize the practicality of a given remote Raman measurement application. Specific applications of Raman scattering to the measurement of atmospheric water vapor profiles, methane plumes from liquid natural gas spills, and subsurface ocean temperature profiles are described. This paper will survey the use of laser Raman measurement techniques in remote sensing applications using as examples specific systems that the Computer Genetics Corporation (CGC) group has developed and engineered.

  16. Future of remote handling

    SciTech Connect

    Grisham, D.L.; Lambert, J.E.

    1986-01-01

    The field of remote handling started in the late 1940's and early 1950's with the invention of mechanical master-slave and electromechanical manipulators. That field now consists of three major divisions: (1) conventional remote handling in fixed facilities with shielding windows and mechanical manipulators; (2) large area remote handling using portable equipment, electric master-slave manipulators, and television for viewing; and (3) the field of robotics which is beginning to be applied to repetitive operations on toxic and dangerous materials. All three divisions will continue to develop and evolve over the next decade.

  17. Emotional memory persists longer than event memory.

    PubMed

    Kuriyama, Kenichi; Soshi, Takahiro; Fujii, Takeshi; Kim, Yoshiharu

    2010-03-01

    The interaction between amygdala-driven and hippocampus-driven activities is expected to explain why emotion enhances episodic memory recognition. However, overwhelming behavioral evidence regarding the emotion-induced enhancement of immediate and delayed episodic memory recognition has not been obtained in humans. We found that the recognition performance for event memory differs from that for emotional memory. Although event recognition deteriorated equally for episodes that were or were not emotionally salient, emotional recognition remained high for only stimuli related to emotional episodes. Recognition performance pertaining to delayed emotional memory is an accurate predictor of the context of past episodes.

  18. Media multitasking and memory: Differences in working memory and long-term memory.

    PubMed

    Uncapher, Melina R; K Thieu, Monica; Wagner, Anthony D

    2016-04-01

    Increasing access to media in the 21st century has led to a rapid rise in the prevalence of media multitasking (simultaneous use of multiple media streams). Such behavior is associated with various cognitive differences, such as difficulty filtering distracting information and increased trait impulsivity. Given the rise in media multitasking by children, adolescents, and adults, a full understanding of the cognitive profile of media multitaskers is imperative. Here we investigated the relationship between chronic media multitasking and working memory (WM) and long-term memory (LTM) performance. Four key findings are reported (1) heavy media multitaskers (HMMs) exhibited lower WM performance, regardless of whether external distraction was present or absent; (2) lower performance on multiple WM tasks predicted lower LTM performance; (3) media multitasking-related differences in memory reflected differences in discriminability rather than decision bias; and (4) attentional impulsivity correlated with media multitasking behavior and reduced WM performance. These findings suggest that chronic media multitasking is associated with a wider attentional scope/higher attentional impulsivity, which may allow goal-irrelevant information to compete with goal-relevant information. As a consequence, heavy media multitaskers are able to hold fewer or less precise goal-relevant representations in WM. HMMs' wider attentional scope, combined with their diminished WM performance, propagates forward to yield lower LTM performance. As such, chronic media multitasking is associated with a reduced ability to draw on the past--be it very recent or more remote--to inform present behavior.

  19. Role of streams in myxobacteria aggregate formation

    NASA Astrophysics Data System (ADS)

    Kiskowski, Maria A.; Jiang, Yi; Alber, Mark S.

    2004-10-01

    Cell contact, movement and directionality are important factors in biological development (morphogenesis), and myxobacteria are a model system for studying cell-cell interaction and cell organization preceding differentiation. When starved, thousands of myxobacteria cells align, stream and form aggregates which later develop into round, non-motile spores. Canonically, cell aggregation has been attributed to attractive chemotaxis, a long range interaction, but there is growing evidence that myxobacteria organization depends on contact-mediated cell-cell communication. We present a discrete stochastic model based on contact-mediated signaling that suggests an explanation for the initialization of early aggregates, aggregation dynamics and final aggregate distribution. Our model qualitatively reproduces the unique structures of myxobacteria aggregates and detailed stages which occur during myxobacteria aggregation: first, aggregates initialize in random positions and cells join aggregates by random walk; second, cells redistribute by moving within transient streams connecting aggregates. Streams play a critical role in final aggregate size distribution by redistributing cells among fewer, larger aggregates. The mechanism by which streams redistribute cells depends on aggregate sizes and is enhanced by noise. Our model predicts that with increased internal noise, more streams would form and streams would last longer. Simulation results suggest a series of new experiments.

  20. JTAG-based remote configuration of FPGAs over optical fibers

    DOE PAGES

    Deng, B.; Xu, H.; Liu, C.; ...

    2015-01-28

    In this study, a remote FPGA-configuration method based on JTAG extension over optical fibers is presented. The method takes advantage of commercial components and ready-to-use software such as iMPACT and does not require any hardware or software development. The method combines the advantages of the slow remote JTAG configuration and the fast local flash memory configuration. The method has been verified successfully and used in the Demonstrator of Liquid-Argon Trigger Digitization Board (LTDB) for the ATLAS liquid argon calorimeter Phase-I trigger upgrade. All components on the FPGA side are verified to meet the radiation tolerance requirements.

  1. Remote Sensing Center

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The applications are reported of new remote sensing techniques for earth resources surveys and environmental monitoring. Applications discussed include: vegetation systems, environmental monitoring, and plant protection. Data processing systems are described.

  2. Acoustic Remote Sensing

    NASA Astrophysics Data System (ADS)

    Dowling, David R.; Sabra, Karim G.

    2015-01-01

    Acoustic waves carry information about their source and collect information about their environment as they propagate. This article reviews how these information-carrying and -collecting features of acoustic waves that travel through fluids can be exploited for remote sensing. In nearly all cases, modern acoustic remote sensing involves array-recorded sounds and array signal processing to recover multidimensional results. The application realm for acoustic remote sensing spans an impressive range of signal frequencies (10-2 to 107 Hz) and distances (10-2 to 107 m) and involves biomedical ultrasound imaging, nondestructive evaluation, oil and gas exploration, military systems, and Nuclear Test Ban Treaty monitoring. In the past two decades, approaches have been developed to robustly localize remote sources; remove noise and multipath distortion from recorded signals; and determine the acoustic characteristics of the environment through which the sound waves have traveled, even when the recorded sounds originate from uncooperative sources or are merely ambient noise.

  3. Remote Sensing Information Classification

    NASA Technical Reports Server (NTRS)

    Rickman, Douglas L.

    2008-01-01

    This viewgraph presentation reviews the classification of Remote Sensing data in relation to epidemiology. Classification is a way to reduce the dimensionality and precision to something a human can understand. Classification changes SCALAR data into NOMINAL data.

  4. Remote hydrogen sensing techniques

    NASA Technical Reports Server (NTRS)

    Perry, Cortes L.

    1992-01-01

    The objective of this project is to evaluate remote hydrogen sensing methodologies utilizing metal oxide semi-conductor field effect transistors (MOS-FET) and mass spectrometric (MS) technologies and combinations thereof.

  5. Remote Sensing Information Gateway

    EPA Pesticide Factsheets

    Remote Sensing Information Gateway, a tool that allows scientists, researchers and decision makers to access a variety of multi-terabyte, environmental datasets and to subset the data and obtain only needed variables, greatly improving the download time.

  6. Remote manipulator dynamic simulation

    NASA Technical Reports Server (NTRS)

    Wild, E. C.; Donges, P. K.; Garand, W. A.

    1972-01-01

    A simulator to generate the real time visual scenes required to perform man in the loop investigations of remote manipulator application and design concepts for the space shuttle is described. The simulated remote manipulator consists of a computed display system that uses a digital computer, the electronic scene generator, an operator's station, and associated interface hardware. A description of the capabilities of the implemented simulation is presented. The mathematical models and programs developed for the simulation are included.

  7. Remote electrochemical sensor

    DOEpatents

    Wang, Joseph; Olsen, Khris; Larson, David

    1997-01-01

    An electrochemical sensor for remote detection, particularly useful for metal contaminants and organic or other compounds. The sensor circumvents technical difficulties that previously prevented in-situ remote operations. The microelectrode, connected to a long communications cable, allows convenient measurements of the element or compound at timed and frequent intervals and instrument/sample distances of ten feet to more than 100 feet. The sensor is useful for both downhole groundwater monitoring and in-situ water (e.g., shipboard seawater) analysis.

  8. Thermal Remote Anemometer Device

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Heath, D. Michele; Winfree, William P.; Miller, William E.; Welch, Christopher S.

    1988-01-01

    Thermal Remote Anemometer Device developed for remote, noncontacting, passive measurement of thermal properties of sample. Model heated locally by scanning laser beam and cooled by wind in tunnel. Thermal image of model analyzed to deduce pattern of airflow around model. For materials applications, system used for evaluation of thin films and determination of thermal diffusivity and adhesive-layer contact. For medical applications, measures perfusion through skin to characterize blood flow and used to determine viabilities of grafts and to characterize tissues.

  9. Wireless remote monitoring system for sleep apnea

    NASA Astrophysics Data System (ADS)

    Oh, Sechang; Kwon, Hyeokjun; Varadan, Vijay K.

    2011-04-01

    Sleep plays the important role of rejuvenating the body, especially the central nervous system. However, more than thirty million people suffer from sleep disorders and sleep deprivation. That can cause serious health consequences by increasing the risk of hypertension, diabetes, heart attack and so on. Apart from the physical health risk, sleep disorders can lead to social problems when sleep disorders are not diagnosed and treated. Currently, sleep disorders are diagnosed through sleep study in a sleep laboratory overnight. This involves large expenses in addition to the inconvenience of overnight hospitalization and disruption of daily life activities. Although some systems provide home based diagnosis, most of systems record the sleep data in a memory card, the patient has to face the inconvenience of sending the memory card to a doctor for diagnosis. To solve the problem, we propose a wireless sensor system for sleep apnea, which enables remote monitoring while the patient is at home. The system has 5 channels to measure ECG, Nasal airflow, body position, abdominal/chest efforts and oxygen saturation. A wireless transmitter unit transmits signals with Zigbee and a receiver unit which has two RF modules, Zigbee and Wi-Fi, receives signals from the transmitter unit and retransmits signals to the remote monitoring system with Zigbee and Wi-Fi, respectively. By using both Zigbee and Wi-Fi, the wireless sensor system can achieve a low power consumption and wide range coverage. The system's features are presented, as well as continuous monitoring results of vital signals.

  10. FPGA remote update for nuclear environments

    SciTech Connect

    Fernandes, Ana; Pereira, Rita C.; Sousa, Jorge; Carvalho, Paulo F.; Correia, Miguel; Rodrigues, Antonio P.; Carvalho, Bernardo B.; Goncalves, Bruno; Correia, Carlos M.B.A.

    2015-07-01

    The Instituto de Plasmas e Fusao Nuclear (IPFN) has developed dedicated re-configurable modules based on field programmable gate array (FPGA) devices for several nuclear fusion machines worldwide. Moreover, new Advanced Telecommunication Computing Architecture (ATCA) based modules developed by IPFN are already included in the ITER catalogue. One of the requirements for re-configurable modules operating in future nuclear environments including ITER is the remote update capability. Accordingly, this work presents an alternative method for FPGA remote programing to be implemented in new ATCA based re-configurable modules. FPGAs are volatile devices and their programming code is usually stored in dedicated flash memories for properly configuration during module power-on. The presented method is capable to store new FPGA codes in Serial Peripheral Interface (SPI) flash memories using the PCIexpress (PCIe) network established on the ATCA back-plane, linking data acquisition endpoints and the data switch blades. The method is based on the Xilinx Quick Boot application note, adapted to PCIe protocol and ATCA based modules. (authors)

  11. Oligomeric baroeffect and gas aggregation states

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1992-01-01

    The baroeffect is analyzed to include a gas that aggregates into higher-order polymers or oligomers. The resulting pressure change is found to vary independently of the molecular weight of the gas components and to depend only on the aggregation or oligomeric order of the gas. With increasing aggregation, diffusive slip velocities are found to increase. The calculations are extended to include general counterdiffusion of two distinct aggregation states (k-, j-mer) for the gas, and the pressure change is derived as a function that is independent of both molecular weight and the absolute aggregation. The only parameter that determines the baroeffect is the ratio of aggregated states, beta = k/j. For gases that reversibly aggregate, possible oscillatory behavior and complex dynamics for pressure are discussed. Gas aggregation may play a role for low-temperature crystal-growth conditions in which vapor concentrations of one (or more) species are high.

  12. Virus-induced aggregates in infected cells.

    PubMed

    Moshe, Adi; Gorovits, Rena

    2012-10-17

    During infection, many viruses induce cellular remodeling, resulting in the formation of insoluble aggregates/inclusions, usually containing viral structural proteins. Identification of aggregates has become a useful diagnostic tool for certain viral infections. There is wide variety of viral aggregates, which differ by their location, size, content and putative function. The role of aggregation in the context of a specific virus is often poorly understood, especially in the case of plant viruses. The aggregates are utilized by viruses to house a large complex of proteins of both viral and host origin to promote virus replication, translation, intra- and intercellular transportation. Aggregated structures may protect viral functional complexes from the cellular degradation machinery. Alternatively, the activation of host defense mechanisms may involve sequestration of virus components in aggregates, followed by their neutralization as toxic for the host cell. The diversity of virus-induced aggregates in mammalian and plant cells is the subject of this review.

  13. Memory Metals

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Under contract to NASA during preparations for the space station, Memry Technologies Inc. investigated shape memory effect (SME). SME is a characteristic of certain metal alloys that can change shape in response to temperature variations. In the late 1980s and early 1990s, Memry used its NASA-acquired expertise to produce a line of home and industrial safety products, and refined the technology in the mid-1990s. Among the new products they developed are three MemrySafe units which prevent scalding from faucets. Each system contains a small valve that reacts to temperature, not pressure. When the water reaches dangerous temperatures, the unit reduces the flow to a trickle; when the scalding temperature subsides, the unit restores normal flow. Other products are the FIRECHEK 2 and 4, heat-activated shutoff valves for industrial process lines, which sense excessive heat and cut off pneumatic pressure. The newest of these products is Memry's Demand Management Water Heater which shifts the electricity requirement from peak to off-peak demands, conserving energy and money.

  14. Thinking Can Cause Forgetting: Memory Dynamics in Creative Problem Solving

    ERIC Educational Resources Information Center

    Storm, Benjamin C.; Angello, Genna; Bjork, Elizabeth Ligon

    2011-01-01

    Research on retrieval-induced forgetting has shown that retrieval can cause the forgetting of related or competing items in memory (Anderson, Bjork, & Bjork, 1994). In the present research, we examined whether an analogous phenomenon occurs in the context of creative problem solving. Using the Remote Associates Test (RAT; Mednick, 1962), we…

  15. Protein aggregation in salt solutions

    PubMed Central

    Kastelic, Miha; Kalyuzhnyi, Yurij V.; Hribar-Lee, Barbara; Dill, Ken A.; Vlachy, Vojko

    2015-01-01

    Protein aggregation is broadly important in diseases and in formulations of biological drugs. Here, we develop a theoretical model for reversible protein–protein aggregation in salt solutions. We treat proteins as hard spheres having square-well-energy binding sites, using Wertheim’s thermodynamic perturbation theory. The necessary condition required for such modeling to be realistic is that proteins in solution during the experiment remain in their compact form. Within this limitation our model gives accurate liquid–liquid coexistence curves for lysozyme and γ IIIa-crystallin solutions in respective buffers. It provides good fits to the cloud-point curves of lysozyme in buffer–salt mixtures as a function of the type and concentration of salt. It than predicts full coexistence curves, osmotic compressibilities, and second virial coefficients under such conditions. This treatment may also be relevant to protein crystallization. PMID:25964322

  16. Aggregation of Heterogeneously Charged Colloids.

    PubMed

    Dempster, Joshua M; Olvera de la Cruz, Monica

    2016-06-28

    Patchy colloids are attractive as programmable building blocks for metamaterials. Inverse patchy colloids, in which a charged surface is decorated with patches of the opposite charge, are additionally noteworthy as models for heterogeneously charged biological materials such as proteins. We study the phases and aggregation behavior of a single charged patch in an oppositely charged colloid with a single-site model. This single-patch inverse patchy colloid model shows a large number of phases when varying patch size. For large patch sizes we find ferroelectric crystals, while small patch sizes produce cross-linked gels. Intermediate values produce monodisperse clusters and unusual worm structures that preserve finite ratios of area to volume. The polarization observed at large patch sizes is robust under extreme disorder in patch size and shape. We examine phase-temperature dependence and coexistence curves and find that large patch sizes produce polarized liquids, in contrast to mean-field predictions. Finally, we introduce small numbers of unpatched charged colloids. These can either suppress or encourage aggregation depending on their concentration and the size of the patches on the patched colloids. These effects can be exploited to control aggregation and to measure effective patch size.

  17. 24 CFR 58.32 - Project aggregation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Project aggregation. 58.32 Section... Environmental Review Process: Documentation, Range of Activities, Project Aggregation and Classification § 58.32 Project aggregation. (a) A responsible entity must group together and evaluate as a single project...

  18. 24 CFR 58.32 - Project aggregation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Project aggregation. 58.32 Section... Environmental Review Process: Documentation, Range of Activities, Project Aggregation and Classification § 58.32 Project aggregation. (a) A responsible entity must group together and evaluate as a single project...

  19. 24 CFR 58.32 - Project aggregation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Project aggregation. 58.32 Section... Environmental Review Process: Documentation, Range of Activities, Project Aggregation and Classification § 58.32 Project aggregation. (a) A responsible entity must group together and evaluate as a single project...

  20. 24 CFR 58.32 - Project aggregation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Project aggregation. 58.32 Section... Environmental Review Process: Documentation, Range of Activities, Project Aggregation and Classification § 58.32 Project aggregation. (a) A responsible entity must group together and evaluate as a single project...

  1. Mineral resource of the month: aggregates

    USGS Publications Warehouse

    Willett, Jason C.

    2012-01-01

    Crushed stone and construction sand and gravel, the two major types of natural aggregates, are among the most abundant and accessible natural resources on the planet. The earliest civilizations used aggregates for various purposes, mainly construction. Today aggregates provide the basic raw materials for the foundation of modern society.

  2. 78 FR 68945 - Aggregation of Positions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ... the aggregation provisions of part 150 of the Commission's regulations that are substantially similar... modifications proposed here to the aggregation provisions of part 150 would apply to the position limits regimes... position limits because it believes that these proposed amendments regarding aggregation of...

  3. Collaborative memory in a serial combination procedure.

    PubMed

    Ditta, Annie Stanfield; Steyvers, Mark

    2013-01-01

    This article describes a new approach for studying collaborative memory that examines people's editing processes for naturally occurring memory errors. In this approach, memories of individuals are combined via a chaining method in which each participant indirectly receives information from the previous participant. Participants were asked to individually study word lists and recall as many words as possible in an online setting. Once a participant completed the recall task, his/her answers were provided for the next participant as suggested answers for their own recall. However, that participant was allowed to add or subtract words from the provided list of suggested answers. The final answer of the group was an aggregate of recalled words based on the answer given by the last participant in the chain. Results showed that participants displayed a very high accuracy of recall throughout the chain, although they were not able to replicate the entire study list or eliminate all errors by the end of the chain. This procedure has the advantage that it allows examination of the memory-editing processes individuals utilise when they communicate information indirectly, independent from social factors that arise in face-to-face group memory settings.

  4. v9fb: a remote framebuffer infrastructure of linux

    SciTech Connect

    Kulkarni, Abhishek; Ionkov, Latchesar

    2008-01-01

    v9fb is a software infrastructure that allows extending framebufFer devices in Linux over the network by providing an abstraction to them in the form of a filesystem hierarchy. Framebuffer based graphic devices export a synthetic filesystem which offers a simple and easy-to-use interface for performing common framebuffer operations. Remote framebuffer devices could be accessed over the network using the 9P protocol support in Linux. We describe the infrastructure in detail and review some of the benefits it offers similar to Plan 9 distributed systems. We discuss the applications of this infrastructure to remotely display and run interactive applications on a terminal while ofFloading the computation to remote servers, and more importantly the flexibility it offers in driving tiled-display walls by aggregating graphic devices in the network.

  5. Early remodeling of the neocortex upon episodic memory encoding.

    PubMed

    Bero, Adam W; Meng, Jia; Cho, Sukhee; Shen, Abra H; Canter, Rebecca G; Ericsson, Maria; Tsai, Li-Huei

    2014-08-12

    Understanding the mechanisms by which long-term memories are formed and stored in the brain represents a central aim of neuroscience. Prevailing theory suggests that long-term memory encoding involves early plasticity within hippocampal circuits, whereas reorganization of the neocortex is thought to occur weeks to months later to subserve remote memory storage. Here we report that long-term memory encoding can elicit early transcriptional, structural, and functional remodeling of the neocortex. Parallel studies using genome-wide RNA sequencing, ultrastructural imaging, and whole-cell recording in wild-type mice suggest that contextual fear conditioning initiates a transcriptional program in the medial prefrontal cortex (mPFC) that is accompanied by rapid expansion of the synaptic active zone and postsynaptic density, enhanced dendritic spine plasticity, and increased synaptic efficacy. To address the real-time contribution of the mPFC to long-term memory encoding, we performed temporally precise optogenetic inhibition of excitatory mPFC neurons during contextual fear conditioning. Using this approach, we found that real-time inhibition of the mPFC inhibited activation of the entorhinal-hippocampal circuit and impaired the formation of long-term associative memory. These findings suggest that encoding of long-term episodic memory is associated with early remodeling of neocortical circuits, identify the prefrontal cortex as a critical regulator of encoding-induced hippocampal activation and long-term memory formation, and have important implications for understanding memory processing in healthy and diseased brain states.

  6. Memory beyond expression.

    PubMed

    Delorenzi, A; Maza, F J; Suárez, L D; Barreiro, K; Molina, V A; Stehberg, J

    2014-01-01

    The idea that memories are not invariable after the consolidation process has led to new perspectives about several mnemonic processes. In this framework, we review our studies on the modulation of memory expression during reconsolidation. We propose that during both memory consolidation and reconsolidation, neuromodulators can determine the probability of the memory trace to guide behavior, i.e. they can either increase or decrease its behavioral expressibility without affecting the potential of persistent memories to be activated and become labile. Our hypothesis is based on the findings that positive modulation of memory expression during reconsolidation occurs even if memories are behaviorally unexpressed. This review discusses the original approach taken in the studies of the crab Neohelice (Chasmagnathus) granulata, which was then successfully applied to test the hypothesis in rodent fear memory. Data presented offers a new way of thinking about both weak trainings and experimental amnesia: memory retrieval can be dissociated from memory expression. Furthermore, the strategy presented here allowed us to show in human declarative memory that the periods in which long-term memory can be activated and become labile during reconsolidation exceeds the periods in which that memory is expressed, providing direct evidence that conscious access to memory is not needed for reconsolidation. Specific controls based on the constraints of reminders to trigger reconsolidation allow us to distinguish between obliterated and unexpressed but activated long-term memories after amnesic treatments, weak trainings and forgetting. In the hypothesis discussed, memory expressibility--the outcome of experience-dependent changes in the potential to behave--is considered as a flexible and modulable attribute of long-term memories. Expression seems to be just one of the possible fates of re-activated memories.

  7. Research on fast Fourier transforms algorithm of huge remote sensing image technology with GPU and partitioning technology.

    PubMed

    Yang, Xue; Li, Xue-You; Li, Jia-Guo; Ma, Jun; Zhang, Li; Yang, Jan; Du, Quan-Ye

    2014-02-01

    Fast Fourier transforms (FFT) is a basic approach to remote sensing image processing. With the improvement of capacity of remote sensing image capture with the features of hyperspectrum, high spatial resolution and high temporal resolution, how to use FFT technology to efficiently process huge remote sensing image becomes the critical step and research hot spot of current image processing technology. FFT algorithm, one of the basic algorithms of image processing, can be used for stripe noise removal, image compression, image registration, etc. in processing remote sensing image. CUFFT function library is the FFT algorithm library based on CPU and FFTW. FFTW is a FFT algorithm developed based on CPU in PC platform, and is currently the fastest CPU based FFT algorithm function library. However there is a common problem that once the available memory or memory is less than the capacity of image, there will be out of memory or memory overflow when using the above two methods to realize image FFT arithmetic. To address this problem, a CPU and partitioning technology based Huge Remote Fast Fourier Transform (HRFFT) algorithm is proposed in this paper. By improving the FFT algorithm in CUFFT function library, the problem of out of memory and memory overflow is solved. Moreover, this method is proved rational by experiment combined with the CCD image of HJ-1A satellite. When applied to practical image processing, it improves effect of the image processing, speeds up the processing, which saves the time of computation and achieves sound result.

  8. DNA methylation in memory formation: Emerging insights

    PubMed Central

    Heyward, Frankie D.; Sweatt, J. David

    2016-01-01

    The establishment of synaptic plasticity and long-term memory requires lasting cellular and molecular modifications that, as a whole, must endure despite the rapid turnover of their constituent parts. Such a molecular feat must be mediated by a stable, self-perpetuating, cellular information storage mechanism. DNA methylation, being the archetypal cellular information storage mechanism, has been heavily implicated as being necessary for stable activity-dependent transcriptional alterations within the central nervous system (CNS). This review details the foundational discoveries from both gene-targeted, as well as whole-genome sequencing, studies that have successfully brought DNA methylation to our attention as a chief regulator of activity- and experience-dependent transcriptional alterations within the CNS. We present a hypothetical framework with which the disparate experimental findings dealing with distinct manipulations of the DNA methylation, and their effect on memory, might be resolved while taking into account the unique impact activity-dependent alterations in DNA methylation potentially have on both memory promoting and memory-suppressing gene expression. And last, we discuss potential avenues for future inquiry into the role of DNA methylation during remote memory formation. PMID:25832671

  9. The dynamics of memory consolidation of landmarks.

    PubMed

    van Ekert, Janneke; Wegman, Joost; Jansen, Clemens; Takashima, Atsuko; Janzen, Gabriele

    2017-04-01

    Navigating through space is fundamental to human nature and requires the ability to retrieve relevant information from the remote past. With the passage of time, some memories become generic, capturing only a sense of familiarity. Yet, others maintain precision, even when acquired decades ago. Understanding the dynamics of memory consolidation is a major challenge to neuroscientists. Using functional magnetic resonance imaging, we systematically examined the effects of time and spatial context on the neural representation of landmark recognition memory. An equal number of male and female subjects (males N = 10, total N = 20) watched a route through a large-scale virtual environment. Landmarks occurred at navigationally relevant and irrelevant locations along the route. Recognition memory for landmarks was tested directly following encoding, 24 h later and 30 days later. Surprisingly, changes over time in the neural representation of navigationally relevant landmarks differed between males and females. In males, relevant landmarks selectively engaged the parahippocampal gyrus (PHG) regardless of the age of the memory. In females, the response to relevant landmarks gradually diminished with time in the PHG but strengthened progressively in the inferior frontal gyrus (IFG). Based on what is known about the functioning of the PHG and IFG, the findings of this study suggest that males maintain access to the initially formed spatial representation of landmarks whereas females become strongly dependent on a verbal representation of landmarks with time. Our findings yield a clear objective for future studies. © 2017 Wiley Periodicals, Inc.

  10. [Lysophosphatidic acid and human erythrocyte aggregation].

    PubMed

    Sheremet'ev, Iu A; Popovicheva, A N; Levin, G Ia

    2014-01-01

    The effects of lysophosphatidic acid on the morphology and aggregation of human erythrocytes has been studied. Morphology of erythrocytes and their aggregates were studied by light microscopy. It has been shown that lysophosphatidic acid changes the shape of red blood cells: diskocyte become echinocytes. Aggregation of red blood cells (rouleaux) was significantly reduced in autoplasma. At the same time there is a strong aggregation of echinocytes. This was accompanied by the formation of microvesicles. Adding normal plasma to echinocytes restores shape and aggregation of red blood cells consisting of "rouleaux". A possible mechanism of action of lysophosphatidic acid on erythrocytes is discussed.

  11. [AGGREGATION OF METABOLICALLY DEPLETED HUMAN ERYTHROCYTES].

    PubMed

    Sheremet'ev, Yu A; Popovicheva, A N; Rogozin, M M; Levin, G Ya

    2016-01-01

    An aggregation of erythrocytes in autologous plasma after blood storage for 14 days at 4 °C was studied using photometry and light microscopy. The decrease of ATP content, the formation of echinocytes and spheroechinocytes, the decrease of rouleaux form of erythrocyte aggregation were observed during the storage. On the other hand the aggregates of echinocytes were formed in the stored blood. The addition of plasma from the fresh blood didn't restore the normal discocytic shape and aggregation of erythrocytes in the stored blood. The possible mechanisms of erythrocytes and echinocytes aggregation are discussed.

  12. Beneficiation of natural aggregates by polymer impregnation

    SciTech Connect

    Webster, R.P.; Fontana, J.J.

    1980-09-01

    The use of polymer impregnation as a means of upgrading natural aggregates has been investigated. The effect of polymer impregnation on the physical and mechanical properties was evaluated in a series of tests performed using four aggregates of varying quality. The strength of concrete cast with polymer impregnated coarse aggregate was also tested. Two monomer systems were used in the investigation; a methyl methacrylate-based system and a styrene-based system. In general, significant improvements in the physical and mechanical properties of each of the four aggregates resulted from polymer impregnation. The strength of concrete cast with impregnated aggregates varied, being increased in some cases and decreased in others.

  13. Remote radiation dosimetry

    DOEpatents

    Braunlich, Peter F.; Tetzlaff, Wolfgang; Hegland, Joel E.; Jones, Scott C.

    1991-01-01

    Disclosed are methods and apparatus for remotely measuring radiation levels. Such are particularly useful for measuring relatively high levels or dosages of radiation being administered in radiation therapy. They are also useful for more general radiation level measurements where remote sensing from the remaining portions of the apparatus is desirable. The apparatus uses a beam generator, such as a laser beam, to provide a stimulating beam. The stimulating beam is preferably of wavelengths shorter than 6 microns, or more advantageously less than 2 microns. The stimulating beam is used to stimulate a remote luminescent sensor mounted in a probe which emits stored luminescent energy resulting from exposure of the sensor to ionizing radiation. The stimulating beam is communicated to the remote luminescent sensor via transmissive fiber which also preferably serves to return the emission from the luminescent sensor. The stimulating beam is advantageously split by a beam splitter to create a detector beam which is measured for power during a reading period during which the luminescent phosphor is read. The detected power is preferably used to control the beam generator to thus produce desired beam power during the reading period. The luminescent emission from the remote sensor is communicated to a suitable emission detector, preferably after filtering or other selective treatment to better isolate the luminescent emission.

  14. Remote radiation dosimetry

    DOEpatents

    Braunlich, P.F.; Tetzlaff, W.; Hegland, J.E.; Jones, S.C.

    1991-03-12

    Disclosed are methods and apparatus for remotely measuring radiation levels. Such are particularly useful for measuring relatively high levels or dosages of radiation being administered in radiation therapy. They are also useful for more general radiation level measurements where remote sensing from the remaining portions of the apparatus is desirable. The apparatus uses a beam generator, such as a laser beam, to provide a stimulating beam. The stimulating beam is preferably of wavelengths shorter than 6 microns, or more advantageously less than 2 microns. The stimulating beam is used to stimulate a remote luminescent sensor mounted in a probe which emits stored luminescent energy resulting from exposure of the sensor to ionizing radiation. The stimulating beam is communicated to the remote luminescent sensor via a transmissive fiber which also preferably serves to return the emission from the luminescent sensor. The stimulating beam is advantageously split by a beam splitter to create a detector beam which is measured for power during a reading period during which the luminescent phosphor is read. The detected power is preferably used to control the beam generator to thus produce desired beam power during the reading period. The luminescent emission from the remote sensor is communicated to a suitable emission detector, preferably after filtering or other selective treatment to better isolate the luminescent emission. 8 figures.

  15. Benzodiazepines and memory

    PubMed Central

    Roth, T.; Roehrs, T.; Wittig, R.; Zorick, F.

    1984-01-01

    1 Benzodiazepines possess anterograde amnesic properties, disrupting both short-term and long-term memory function. 2 The amount of amnesia is systematically related to dose effects and half-life differences among the benzodiazepines. 3 Memory deficits are found for episodic, semantic, and iconic memory function. 4 The deficits in long-term memory are probably the result of a disruption of consolidation of information in memory and not retrieval from memory. The disruption is produced by rapid sleep onset. 5 Thus the long-term amnesia is really a retrograde effect of sleep and not the anterograde effect of the drug. PMID:6151849

  16. Problems of neural memory

    NASA Astrophysics Data System (ADS)

    Mikaelian, Andrei L.

    2005-01-01

    The paper considers the neural memory of the human brain from the viewpoint of visual information processing. A model that explains the principle of data recording and storing, memory relaxation, associative remembering and other memory functions is offered. The model of associative memory is based on the methods of holography, "wave biochemistry" and autowaves. Brief consideration is given to the associative properties of holographic neural structures and the memory architecture using running chemical reactions. The paper also outlines the problem of developing artificial memory elements for restoring the brain functions and possible interface devices for coupling neurons to electronic systems.

  17. Erythrocyte aggregation: basic aspects and clinical importance.

    PubMed

    Baskurt, Oguz K; Meiselman, Herbert J

    2013-01-01

    Red blood cell (RBC) aggregate to form two- and three-dimensional structures when suspended in aqueous solutions containing large plasma proteins or polymers; this aggregation is reversible and shear dependent (i.e., dispersed at high shear and reformed at low or stasis). The extent of aggregation is the main determinant of low shear blood viscosity, thus predicting an inverse relationship between aggregation and in vivo blood flow. However, the effects of aggregation on hemodynamic mechanisms (e.g., plasma skimming, Fåhraeus Effect, microvascular hematocrit) may promote rather than impede vascular blood flow. The impact of enhanced RBC aggregation on endothelial function and hemostatic mechanisms adds further complexity, thereby requiring specific attention to the nature, extent and time course of aggregation when considering its overall influence on tissue perfusion. A detailed understanding of aggregation effects is important from a clinical point of view since it may be enhanced during a variety of pathophysiological processes, including infections, circulatory and metabolic disorders, hematological pathologies and several other disease states. Altered RBC aggregation may be an indicator of disease as well as a factor affecting the course of the clinical condition; the prognostic value of RBC aggregation indices has been demonstrated in various diseases. Currently, RBC aggregation is an easily and accurately measurable parameter, and therefore may be expected to have broader clinical usage in the future.

  18. Geologic and societal factors affecting the international oceanic transport of aggregate

    USGS Publications Warehouse

    Langer, W.H.

    1995-01-01

    Crushed stone and sand and gravel are the two main sources of natural aggregate, and together comprise approximately half the volume and tonnage of mined material in the United States. Natural aggregate is a bulky, heavy material without special or unique properties, and it is commonly used near its source of production to minimize haulage cost. However, remoteness is no longer an absolute disqualifier for the production of aggregate. Today interstate aggregate routinely is shipped hundreds of kilometers by rail and barge. In addition, during 1992, the United States imported 1,317,000 metric tons of aggregate from Canada and 1,531,000 metric tons from Mexico. A number of ports on the Atlantic Coast and Gulf Coast of the United States receive imports of crushed stone from foreign sources for transport to various parts of the eastern United States. These areas either lack adequate supplies of aggregate or are augmenting their supplies because they have difficulties meeting current demand. These difficulties may include poor stone quality, environmental permitting problems, or transportation. Certain societal and geologic conditions of New York City and Philadelphia along the Atlantic Coast, and Tampa and New Orleans along the Gulf Coast, are discussed to demonstrate the different combinations of issues that contribute to the economic viability of importing crushed stone. ?? 1995 Oxford University Press.

  19. Simulation of J-aggregate microcavity photoluminescence

    NASA Astrophysics Data System (ADS)

    Michetti, Paolo; La Rocca, Giuseppe C.

    2008-05-01

    We have developed a model in order to account for the photoexcitation dynamics of J-aggregate films and strongly coupled J-aggregate microcavities. The J aggregates are described as a disordered Frenkel exciton system in which relaxation occurs due to the presence of a thermal bath of molecular vibrations. The correspondence between the photophysics in J-aggregate films and that in J-aggregate microcavities is obtained by introducing a model polariton wave function mixing cavity photon modes and J-aggregate super-radiant excitons. With the same description of the material properties, we have calculated both absorption and luminescence spectra for the J-aggregate film and the photoluminescence of strongly coupled organic microcavities. The model is able to account for the fast relaxation dynamics in organic microcavities following nonresonant pumping and explains the temperature dependence of the ratio between the upper polariton and the lower polariton luminescence.

  20. Microwave extinction characteristics of nanoparticle aggregates

    NASA Astrophysics Data System (ADS)

    Wu, Y. P.; Cheng, J. X.; Liu, X. X.; Wang, H. X.; Zhao, F. T.; Wen, W. W.

    2016-07-01

    Structure of nanoparticle aggregates plays an important role in microwave extinction capacity. The diffusion-limited aggregation model (DLA) for fractal growth is utilized to explore the possible structures of nanoparticle aggregates by computer simulation. Based on the discrete dipole approximation (DDA) method, the microwave extinction performance by different nano-carborundum aggregates is numerically analyzed. The effects of the particle quantity, original diameter, fractal structure, as well as orientation on microwave extinction are investigated, and also the extinction characteristics of aggregates are compared with the spherical nanoparticle in the same volume. Numerical results give out that proper aggregation of nanoparticle is beneficial to microwave extinction capacity, and the microwave extinction cross section by aggregated granules is better than that of the spherical solid one in the same volume.

  1. Method of up-front load balancing for local memory parallel processors

    NASA Technical Reports Server (NTRS)

    Baffes, Paul Thomas (Inventor)

    1990-01-01

    In a parallel processing computer system with multiple processing units and shared memory, a method is disclosed for uniformly balancing the aggregate computational load in, and utilizing minimal memory by, a network having identical computations to be executed at each connection therein. Read-only and read-write memory are subdivided into a plurality of process sets, which function like artificial processing units. Said plurality of process sets is iteratively merged and reduced to the number of processing units without exceeding the balance load. Said merger is based upon the value of a partition threshold, which is a measure of the memory utilization. The turnaround time and memory savings of the instant method are functions of the number of processing units available and the number of partitions into which the memory is subdivided. Typical results of the preferred embodiment yielded memory savings of from sixty to seventy five percent.

  2. Remote connector development study

    SciTech Connect

    Parazin, R.J.

    1995-05-01

    Plutonium-uranium extraction (PUREX) connectors, the most common connectors used at the Hanford site, offer a certain level of flexibility in pipe routing, process system configuration, and remote equipment/instrument replacement. However, these desirable features have inherent shortcomings like leakage, high pressure drop through the right angle bends, and a limited range of available pipe diameters that can be connect by them. Costs for construction, maintenance, and operation of PUREX connectors seem to be very high. The PUREX connector designs include a 90{degree} bend in each connector. This increases the pressure drop and erosion effects. Thus, each jumper requires at least two 90{degree} bends. PUREX connectors have not been practically used beyond 100 (4 in.) inner diameter. This study represents the results of a survey on the use of remote pipe-connection systems in US and foreign plants. This study also describes the interdependence between connectors, remote handling equipment, and the necessary skills of the operators.

  3. EPA Remote Sensing Information Gateway

    NASA Astrophysics Data System (ADS)

    Paulsen, H. K.; Szykman, J. J.; Plessel, T.; Freeman, M.; Dimmick, F.

    2009-12-01

    The Remote Sensing Information Gateway was developed by the U.S. Environmental Protection Agency (EPA) to assist researchers in easily obtaining and combining a variety of environmental datasets related to air quality research. Current datasets available include, but are not limited to surface PM2.5 and O3 data, satellite derived aerosol optical depth , and 3-dimensional output from U.S. EPA's Models 3/Community Multi-scale Air Quality (CMAQ) modeling system. The presentation will include a demonstration that illustrates several scenarios of how researchers use the tool to help them visualize and obtain data for their work; with a particular focus on episode analysis related to biomass burning impacts on air quality. The presentation will provide an overview on how RSIG works and how the code has been—and can be—adapted for other projects. One example is the Virtual Estuary, which focuses on automating the retrieval and pre-processing of a variety of data needed for estuarine research. RSIG’s source codes are freely available to researchers with permission from the EPA principal investigator, Dr. Jim Szykman. RSIG is available to the community and can be accessed online at http://www.epa.gov/rsig. Once the JAVA policy file is configured on your computer you can run the RSIG applet on your computer and connect to the RSIG server to visualize and retrieve available data sets. The applet allows the user to specify the temporal/spatial areas of interest, and the types of data to retrieve. The applet then communicates with RSIG subsetter codes located on the data owners’ remote servers; the subsetter codes assemble and transfer via ordinary Internet protocols only the specified data to the researcher’s computer. This is much faster than the usual method of transferring large files via FTP and greatly reduces network traffic. The RSIG applet then visualizes the transferred data on a latitude-longitude map, automatically locating the data in the correct

  4. Aggregation Kinetics of Interrupted Polyglutamine Peptides

    PubMed Central

    Walters, Robert H.; Murphy, Regina M.

    2011-01-01

    Abnormally expanded polyglutamine domains are associated with at least nine neurodegenerative diseases, including Huntington’s disease. Expansion of the glutamine region facilitates aggregation of the impacted protein, and aggregation has been linked to neurotoxicity. Studies of synthetic peptides have contributed substantially to our understanding of the mechanism of aggregation, because the underlying biophysics of polyglutamine-mediated association can be probed independent of their context within a larger protein. In this report, interrupting residues were inserted into polyglutamine peptides (Q20), and the impact on conformational and aggregation properties was examined. A peptide with 2 alanine residues formed laterally-aligned fibrillar aggregates which were similar to the uninterrupted Q20 peptide. Insertion of 2 proline residues resulted in soluble, nonfibrillar aggregates, which did not mature into insoluble aggregates. In contrast, insertion of a β-turn template DPG rapidly accelerated aggregation and resulted in a fibrillar aggregate morphology with little lateral alignment between fibrils. These results are interpreted to indicate that (a) long-range nonspecific interactions lead to the formation of soluble oligomers, while maturation of oligomers into fibrils requires conformational conversion, and (b) that soluble oligomers dynamically interact with each other, while insoluble aggregates are relatively inert. Kinetic analysis revealed that the increase in aggregation caused by the DPG insert is inconsistent with the nucleation-elongation mechanism of aggregation featuring a monomeric β-sheet nucleus. Rather, the data support a mechanism of polyglutamine aggregation by which monomers associate into soluble oligomers, which then undergo slow structural rearrangement to form sedimentable aggregates. PMID:21821045

  5. Aggregation and Association of NDVI, Boll Injury, and Stink Bugs in North Carolina Cotton.

    PubMed

    Reisig, Dominic D; Reay-Jones, F P F; Meijer, A D

    2015-01-01

    Sampling of herbivorous stink bugs in southeastern U.S. cotton remains problematic. Remote sensing was explored to improve sampling of these pests and associated boll injury. Two adjacent 14.5-ha cotton fields were grid sampled in 2011 and 2012 by collecting stink bug adults and bolls every week during the third, fourth, and fifth weeks of bloom. Satellite remote sensing data were collected during the third week of bloom during both years, and normalized difference vegetation index (NDVI) values were calculated. Stink bugs were spatially aggregated on the third week of bloom in 2011. Boll injury from stink bugs was spatially aggregated during the fourth week of bloom in 2012. The NDVI values were aggregated during both years. There was a positive association and correlation between stink bug numbers and NDVI values, as well as injured bolls and NDVI values, during the third week of bloom in 2011. During the third week of bloom in 2012, NDVI values were negatively correlated with stink bug numbers. During the fourth week of bloom in 2011, stink bug numbers and boll injury were both positively associated and correlated with NDVI values. During the fourth week of bloom in 2012, stink bugs were negatively correlated with NDVI values, and boll injury was negatively associated and correlated with NDVI values. This study suggests the potential of remote sensing as a tool to assist with sampling stink bugs in cotton, although more research is needed using NDVI and other plant measurements to predict stink bug injury.

  6. Aggregation and Association of NDVI, Boll Injury, and Stink Bugs in North Carolina Cotton

    PubMed Central

    Reisig, Dominic D.; Reay-Jones, F. P. F.; Meijer, A. D.

    2015-01-01

    Sampling of herbivorous stink bugs in southeastern U.S. cotton remains problematic. Remote sensing was explored to improve sampling of these pests and associated boll injury. Two adjacent 14.5-ha cotton fields were grid sampled in 2011 and 2012 by collecting stink bug adults and bolls every week during the third, fourth, and fifth weeks of bloom. Satellite remote sensing data were collected during the third week of bloom during both years, and normalized difference vegetation index (NDVI) values were calculated. Stink bugs were spatially aggregated on the third week of bloom in 2011. Boll injury from stink bugs was spatially aggregated during the fourth week of bloom in 2012. The NDVI values were aggregated during both years. There was a positive association and correlation between stink bug numbers and NDVI values, as well as injured bolls and NDVI values, during the third week of bloom in 2011. During the third week of bloom in 2012, NDVI values were negatively correlated with stink bug numbers. During the fourth week of bloom in 2011, stink bug numbers and boll injury were both positively associated and correlated with NDVI values. During the fourth week of bloom in 2012, stink bugs were negatively correlated with NDVI values, and boll injury was negatively associated and correlated with NDVI values. This study suggests the potential of remote sensing as a tool to assist with sampling stink bugs in cotton, although more research is needed using NDVI and other plant measurements to predict stink bug injury. PMID:26411787

  7. Applied remote sensing

    SciTech Connect

    Lo, C.P.

    1986-01-01

    The author presents selected case studies to demonstrate theories and practices of remote sensing and its value to the study of the terrestrial environment. Begins with an overview of sensor types and electromagnetic remote sensing, continuing with an examination of photographic and non-photographic systems in the study of the radiation budget, temperature structure and weather conditions of the atmosphere. Includes thorough coverage of the lithosphere, biosphere and hydrosphere, as well as the cartographic problems involved in land use/land cover and topographic mapping. Concludes with a discussion of the impact of electromagnetic computers in the development of geographic information systems.

  8. Remote air pollution measurement

    NASA Technical Reports Server (NTRS)

    Byer, R. L.

    1975-01-01

    This paper presents a discussion and comparison of the Raman method, the resonance and fluorescence backscatter method, long path absorption methods and the differential absorption method for remote air pollution measurement. A comparison of the above remote detection methods shows that the absorption methods offer the most sensitivity at the least required transmitted energy. Topographical absorption provides the advantage of a single ended measurement, and differential absorption offers the additional advantage of a fully depth resolved absorption measurement. Recent experimental results confirming the range and sensitivity of the methods are presented.

  9. Remote Reactor Monitoring

    SciTech Connect

    Bernstein, Adam; Dazeley, Steve; Dobie, Doug; Marleau, Peter; Brennan, Jim; Gerling, Mark; Sumner, Matthew; Sweany, Melinda

    2014-10-21

    The overall goal of the WATCHMAN project is to experimentally demonstrate the potential of water Cerenkov antineutrino detectors as a tool for remote monitoring of nuclear reactors. In particular, the project seeks to field a large prototype gadolinium-doped, water-based antineutrino detector to demonstrate sensitivity to a power reactor at ~10 kilometer standoff using a kiloton scale detector. The technology under development, when fully realized at large scale, could provide remote near-real-time information about reactor existence and operational status for small operating nuclear reactors out to distances of many hundreds of kilometers.

  10. Aerosol Remote Sensing

    NASA Technical Reports Server (NTRS)

    Lenoble, Jacqueline (Editor); Remer, Lorraine (Editor); Tanre, Didier (Editor)

    2012-01-01

    This book gives a much needed explanation of the basic physical principles of radia5tive transfer and remote sensing, and presents all the instruments and retrieval algorithms in a homogenous manner. For the first time, an easy path from theory to practical algorithms is available in one easily accessible volume, making the connection between theoretical radiative transfer and individual practical solutions to retrieve aerosol information from remote sensing. In addition, the specifics and intercomparison of all current and historical methods are explained and clarified.

  11. Radar Remote Sensing

    NASA Technical Reports Server (NTRS)

    Rosen, Paul A.

    2012-01-01

    This lecture was just a taste of radar remote sensing techniques and applications. Other important areas include Stereo radar grammetry. PolInSAR for volumetric structure mapping. Agricultural monitoring, soil moisture, ice-mapping, etc. The broad range of sensor types, frequencies of observation and availability of sensors have enabled radar sensors to make significant contributions in a wide area of earth and planetary remote sensing sciences. The range of applications, both qualitative and quantitative, continue to expand with each new generation of sensors.

  12. Remote electrochemical sensor

    DOEpatents

    Wang, J.; Olsen, K.; Larson, D.

    1997-10-14

    An electrochemical sensor is described for remote detection, particularly useful for metal contaminants and organic or other compounds. The sensor circumvents technical difficulties that previously prevented in-situ remote operations. The microelectrode, connected to a long communications cable, allows convenient measurements of the element or compound at timed and frequent intervals and instrument/sample distances of ten feet to more than 100 feet. The sensor is useful for both downhole groundwater monitoring and in-situ water (e.g., shipboard seawater) analysis. 21 figs.

  13. Anthropomorphic Remote Manipulator

    NASA Technical Reports Server (NTRS)

    Jau, Bruno M.

    1991-01-01

    Two-armed telerobot undergoing development manipulates objects with dexterity approaching that of human. Designed to be remotely operated by human. Operator wears harness with exoskeletonlike sleeves and gloves; remote manipulator follows operator's arm, hand, and finger movements and feeds back position and force information so operator has sense of manipulating object held by telerobot. Developed for use in outer space. Suited for such terrestrial uses as handling materials and maintaining equipment in hazardous environments where mechanical dexterity and nearly instantaneous feedback of sensory information needed.

  14. Searching for repressed memory.

    PubMed

    McNally, Richard J

    2012-01-01

    This chapter summarizes the work of my research group on adults who report either repressed, recovered, or continuous memories of childhood sexual abuse (CSA) or who report no history of CSA. Adapting paradigms from cognitive psychology, we tested hypotheses inspired by both the "repressed memory" and "false memory" perspectives on recovered memories of CSA. We found some evidence for the false memory perspective, but no evidence for the repressed memory perspective. However, our work also suggests a third perspective on recovered memories that does not require the concept of repression. Some children do not understand their CSA when it occurs, and do not experience terror. Years later, they recall the experience, and understanding it as abuse, suffer intense distress. The memory failed to come to mind for years, partly because the child did not encode it as terrifying (i.e., traumatic), not because the person was unable to recall it.

  15. Emotional Memory Persists Longer than Event Memory

    ERIC Educational Resources Information Center

    Kuriyama, Kenichi; Soshi, Takahiro; Fujii, Takeshi; Kim, Yoshiharu

    2010-01-01

    The interaction between amygdala-driven and hippocampus-driven activities is expected to explain why emotion enhances episodic memory recognition. However, overwhelming behavioral evidence regarding the emotion-induced enhancement of immediate and delayed episodic memory recognition has not been obtained in humans. We found that the recognition…

  16. Complementary roles of slow-wave sleep and rapid eye movement sleep in emotional memory consolidation.

    PubMed

    Cairney, Scott A; Durrant, Simon J; Power, Rebecca; Lewis, Penelope A

    2015-06-01

    Although rapid eye movement sleep (REM) is regularly implicated in emotional memory consolidation, the role of slow-wave sleep (SWS) in this process is largely uncharacterized. In the present study, we investigated the relative impacts of nocturnal SWS and REM upon the consolidation of emotional memories using functional magnetic resonance imaging (fMRI) and polysomnography (PSG). Participants encoded emotionally positive, negative, and neutral images (remote memories) before a night of PSG-monitored sleep. Twenty-four hours later, they encoded a second set of images (recent memories) immediately before a recognition test in an MRI scanner. SWS predicted superior memory for remote negative images and a reduction in right hippocampal responses during the recollection of these items. REM, however, predicted an overnight increase in hippocampal-neocortical connectivity associated with negative remote memory. These findings provide physiological support for sequential views of sleep-dependent memory processing, demonstrating that SWS and REM serve distinct but complementary functions in consolidation. Furthermore, these findings extend those ideas to emotional memory by showing that, once selectively reorganized away from the hippocampus during SWS, emotionally aversive representations undergo a comparably targeted process during subsequent REM.

  17. Investigating the mechanisms leading to protein aggregation

    NASA Astrophysics Data System (ADS)

    McNamara, Ruth; McManus, Jennifer J.

    2014-03-01

    The formation of protein aggregates is a feature of several diseases and is a problem during the manufacture of biopharmaceutical and protein based food products. During processing, stability may become compromised leading to the condensation of proteins to form non-native aggregates. The aim of this work is to induce aggregation on model proteins by the imposition of a particular stress to evaluate the extent of aggregation and to assess the degree of structural change to the protein. Aggregation of two proteins, lysozyme and bovine serum albumin has been induced by several mechanisms. Using various techniques (electrophoresis, HPLC, spectroscopic analysis, and microscopic techniques) both the level of aggregation extent of protein unfolding has been investigated for a range of solution conditions. Our results show that the amount of aggregation depends strongly on the mechanism by which non-native aggregation proceeds, and within each mechanism, solution conditions are an important factor. With the exception of aggregation by self-association (which is concentration dependent), the appearance of aggregation is driven by structural changes induced by the applied stress (heat, chemical denaturant, oxidation or contact with a surface). Author would like to acknowledge support from Science Foundation Ireland (SFI), National University of Maynooth John and Pat Hume Scholarship.

  18. Applications of aggregation theory to sustainability assessment

    DOE PAGES

    Pollesch, N.; Dale, V. H.

    2015-04-01

    In order to aid in transition towards operations that promote sustainability goals, researchers and stakeholders use sustainability assessments. Although assessments take various forms, many utilize diverse sets of indicators that can number anywhere from two to over 2000. Indices, composite indicators, or aggregate values are used to simplify high dimensional and complex data sets and to clarify assessment results. Although the choice of aggregation function is a key component in the development of the assessment, there are few examples to be found in literature to guide appropriate aggregation function selection. This paper develops a connection between the mathematical study ofmore » aggregation functions and sustainability assessment in order to aid in providing criteria for aggregation function selection. Relevant mathematical properties of aggregation functions are presented and interpreted. Lastly, we provide cases of these properties and their relation to previous sustainability assessment research. Examples show that mathematical aggregation properties can be used to address the topics of compensatory behavior and weak versus strong sustainability, aggregation of data under varying units of measurements, multiple site multiple indicator aggregation, and the determination of error bounds in aggregate output for normalized and non-normalized indicator measures.« less

  19. Applications of aggregation theory to sustainability assessment

    SciTech Connect

    Pollesch, N.; Dale, V. H.

    2015-04-01

    In order to aid in transition towards operations that promote sustainability goals, researchers and stakeholders use sustainability assessments. Although assessments take various forms, many utilize diverse sets of indicators that can number anywhere from two to over 2000. Indices, composite indicators, or aggregate values are used to simplify high dimensional and complex data sets and to clarify assessment results. Although the choice of aggregation function is a key component in the development of the assessment, there are few examples to be found in literature to guide appropriate aggregation function selection. This paper develops a connection between the mathematical study of aggregation functions and sustainability assessment in order to aid in providing criteria for aggregation function selection. Relevant mathematical properties of aggregation functions are presented and interpreted. Lastly, we provide cases of these properties and their relation to previous sustainability assessment research. Examples show that mathematical aggregation properties can be used to address the topics of compensatory behavior and weak versus strong sustainability, aggregation of data under varying units of measurements, multiple site multiple indicator aggregation, and the determination of error bounds in aggregate output for normalized and non-normalized indicator measures.

  20. Sectoral shifts and aggregate unemployment

    SciTech Connect

    Loungani, P.

    1986-01-01

    Some recent research has taken the view that sectoral or industry-specific shocks significantly affect aggregate unemployment by increasing the amount of inter-industry labor reallocation required. The empirical evidence for this view rests on the finding that during the 1950s - and again during the 1970s - there was a positive correlation between aggregate unemployment and the dispersion of employment growth rates. This thesis demonstrates that this correlation arises largely because oil price shocks affect both unemployment and the dispersion of employment growth. Once the dispersion due to oil shocks is accounted for, the residual dispersion in employment has very low explanatory power for unemployment. Since the dispersion index does not measure pure sectoral shifts, an alternate measure of dispersion is developed that serves as a better proxy for the amount of inter-industry labor reallocation required each period. Estimates using this measure suggest that, during the 1950s, temporary increases in the relative price of oil were responsible for generating the observed correlation. On the other hand, sectoral shifts were important during the 1970s; in particular, the 1973 oil price increase has had significant reallocative effects on the economy. This contention is subjected to further tests by looking at the time-series behavior of employment in durable-goods industries and also by following the inter-industry movements of workers over time through the use of panel data.

  1. Asphaltene aggregation in organic solvents.

    PubMed

    Oh, Kyeongseok; Ring, Terry A; Deo, Milind D

    2004-03-01

    Asphaltenic solids formed in the Rangely field in the course of a carbon dioxide flood and heptane insolubles in the oil from the same field were used in this study. Four different solvents were used to dissolve the asphaltenes. Near-infrared (NIR) spectroscopy was used to determine the onset of asphaltene precipitation by heptane titration. When the onset values were plotted versus asphaltene concentrations, distinct break points (called critical aggregation concentrations (CAC) in this paper) were observed. CACs for the field asphaltenes dissolved in toluene, trichloroethylene, tetrahydrofuran, and pyridine occurred at concentrations of 3.0, 3.7, 5.0, and 8.2 g/l, respectively. CACs are observed at similar concentrations as critical micelle concentrations (CMC) for the asphaltenes in the solvents employed and can be interpreted to be the points at which rates of asphaltene aggregations change. CMC values of asphaltenes determined from surface tension measurements (in pyridine and TCE) were slightly higher than the CAC values measured by NIR onset measurements. The CAC for heptane-insoluble asphaltenes in toluene was 3.1 g/l. Thermal gravimetric analysis (TGA) and elemental compositions of the two asphaltenes showed that the H/C ratio of the heptane-insoluble asphaltenes was higher and molecular weight (measured by vapor pressure osmometry) was lower.

  2. Detergent-mediated protein aggregation.

    PubMed

    Neale, Chris; Ghanei, Hamed; Holyoake, John; Bishop, Russell E; Privé, Gilbert G; Pomès, Régis

    2013-04-01

    Because detergents are commonly used to solvate membrane proteins for structural evaluation, much attention has been devoted to assessing the conformational bias imparted by detergent micelles in comparison to the native environment of the lipid bilayer. Here, we conduct six 500-ns simulations of a system with >600,000 atoms to investigate the spontaneous self assembly of dodecylphosphocholine detergent around multiple molecules of the integral membrane protein PagP. This detergent formed equatorial micelles in which acyl chains surround the protein's hydrophobic belt, confirming existing models of the detergent solvation of membrane proteins. In addition, unexpectedly, the extracellular and periplasmic apical surfaces of PagP interacted with the headgroups of detergents in other micelles 85 and 60% of the time, respectively, forming complexes that were stable for hundreds of nanoseconds. In some cases, an apical surface of one molecule of PagP interacted with an equatorial micelle surrounding another molecule of PagP. In other cases, the apical surfaces of two molecules of PagP simultaneously bound a neat detergent micelle. In these ways, detergents mediated the non-specific aggregation of folded PagP. These simulation results are consistent with dynamic light scattering experiments, which show that, at detergent concentrations ≥600 mM, PagP induces the formation of large scattering species that are likely to contain many copies of the PagP protein. Together, these simulation and experimental results point to a potentially generic mechanism of detergent-mediated protein aggregation.

  3. Memory and the Self

    ERIC Educational Resources Information Center

    Conway, Martin A.

    2005-01-01

    The Self-Memory System (SMS) is a conceptual framework that emphasizes the interconnectedness of self and memory. Within this framework memory is viewed as the data base of the self. The self is conceived as a complex set of active goals and associated self-images, collectively referred to as the "working self." The relationship between the…

  4. Music, memory and emotion.

    PubMed

    Jäncke, Lutz

    2008-08-08

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory.

  5. Role of Multicellular Aggregates in Biofilm Formation

    PubMed Central

    Kragh, Kasper N.; Hutchison, Jaime B.; Melaugh, Gavin; Rodesney, Chris; Roberts, Aled E. L.; Irie, Yasuhiko; Jensen, Peter Ø.; Diggle, Stephen P.; Allen, Rosalind J.

    2016-01-01

    ABSTRACT In traditional models of in vitro biofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development of Pseudomonas aeruginosa biofilms. We find that the relative fitness of aggregates depends markedly on the density of surrounding single cells, i.e., the level of competition for growth resources. When competition between aggregates and single cells is low, an aggregate has a growth disadvantage because the aggregate interior has poor access to growth resources. However, if competition is high, aggregates exhibit higher fitness, because extending vertically above the surface gives cells at the top of aggregates better access to growth resources. Other advantages of seeding by aggregates, such as earlier switching to a biofilm-like phenotype and enhanced resilience toward antibiotics and immune response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation. PMID:27006463

  6. Remotely controlled spray gun

    NASA Technical Reports Server (NTRS)

    Cunningham, William C. (Inventor)

    1987-01-01

    A remotely controlled spray gun is described in which a nozzle and orifice plate are held in precise axial alignment by an alignment member, which in turn is held in alignment with the general outlet of the spray gun by insert. By this arrangement, the precise repeatability of spray patterns is insured.

  7. Remote systems development

    NASA Technical Reports Server (NTRS)

    Olsen, R.; Schaefer, O.; Hussey, J.

    1992-01-01

    Potential space missions of the nineties and the next century require that we look at the broad category of remote systems as an important means to achieve cost-effective operations, exploration and colonization objectives. This paper addresses such missions, which can use remote systems technology as the basis for identifying required capabilities which must be provided. The relationship of the space-based tasks to similar tasks required for terrestrial applications is discussed. The development status of the required technology is assessed and major issues which must be addressed to meet future requirements are identified. This includes the proper mix of humans and machines, from pure teleoperation to full autonomy; the degree of worksite compatibility for a robotic system; and the required design parameters, such as degrees-of-freedom. Methods for resolution are discussed including analysis, graphical simulation and the use of laboratory test beds. Grumman experience in the application of these techniques to a variety of design issues are presented utilizing the Telerobotics Development Laboratory which includes a 17-DOF robot system, a variety of sensing elements, Deneb/IRIS graphics workstations and control stations. The use of task/worksite mockups, remote system development test beds and graphical analysis are discussed with examples of typical results such as estimates of task times, task feasibility and resulting recommendations for design changes. The relationship of this experience and lessons-learned to future development of remote systems is also discussed.

  8. Application of remote sensing

    NASA Technical Reports Server (NTRS)

    Graff, W. J. (Compiler)

    1973-01-01

    Remote sensing and aerial photographic interpretation are discussed along with the specific imagery techniques used for this research. The method used to select sites, the results of data analyses for the Houston metropolitan area, and the location of dredging sites along the Houston Ship Channel are presented. The work proposed for the second year of the project is described.

  9. Engaging Remote Computing Students

    ERIC Educational Resources Information Center

    Summers, Derek; Douglas, Gillian

    2011-01-01

    The use of a range of technologies is a feature of pedagogies used across higher education provision in the UK. The University of the Highlands and Islands (UHI) provides higher education in the most rural and remote region of the UK, so the use of technologies is at the forefront of approaches to learning and teaching. This reflective article…

  10. EPA REMOTE SENSING RESEARCH

    EPA Science Inventory

    The 2006 transgenic corn imaging research campaign has been greatly assisted through a cooperative effort with several Illinois growers who provided planting area and crop composition. This research effort was designed to evaluate the effectiveness of remote sensed imagery of var...

  11. Solar System Remote Sensing

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This volume contains abstracts that have been accepted for presentation at the symposium on Solar System Remote Sensing, September 20-21, 2002, in Pittsburgh, Pennsylvania. Administration and publications support for this meeting were provided by the staff of the Publications and Program Services Departments at the Lunar and Planetary Institute.

  12. Remote Inspection Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2013-01-01

    The ability to remotely inspect equipment of an aging infrastructure is becoming of major interest to many industries. Often the ability to just get a look at a piece of critical equipment can yield very important information. With millions of miles of piping installed throughout the United States, this vast network is critical to oil, natural…

  13. Remote Agent Experiment

    NASA Technical Reports Server (NTRS)

    Benard, Doug; Dorais, Gregory A.; Gamble, Ed; Kanefsky, Bob; Kurien, James; Millar, William; Muscettola, Nicola; Nayak, Pandu; Rouquette, Nicolas; Rajan, Kanna; Norvig, Peter (Technical Monitor)

    2000-01-01

    Remote Agent (RA) is a model-based, reusable artificial intelligence (At) software system that enables goal-based spacecraft commanding and robust fault recovery. RA was flight validated during an experiment on board of DS1 between May 17th and May 21th, 1999.

  14. Remote Access Astronomy

    ERIC Educational Resources Information Center

    Beare, Richard; Bowdley, David; Newsam, Andrew; Roche, Paul

    2003-01-01

    There is still nothing to beat the excitement and fulfilment that you can get from observing celestial bodies on a clear dark night, in a remote location away from the seemingly ever increasing light pollution from cities. However, it is also the specific requirements for good observing that can sometimes prevent teachers from offering this…

  15. Remote Sensing and the Earth

    NASA Technical Reports Server (NTRS)

    Brosius, C. A.; Gervin, J. C.; Ragusa, J. M.

    1977-01-01

    A text book on remote sensing, as part of the earth resources Skylab programs, is presented. The fundamentals of remote sensing and its application to agriculture, land use, geology, water and marine resources, and environmental monitoring are summarized.

  16. Distribution of algal aggregates under summer sea ice in the Central Arctic.

    PubMed

    Katlein, Christian; Fernández-Méndez, Mar; Wenzhöfer, Frank; Nicolaus, Marcel

    The sea ice cover of the Arctic Ocean has changed dramatically in the last decades, and the resulting consequences for the sea-ice-associated ecosystem remain difficult to assess. Algal aggregates underneath sea ice are of great importance for the ice-associated ecosystem and the pelagic-benthic coupling. However, the frequency and distribution of their occurrence is not well quantified. During the IceArc expedition (ARK-27/3) of RV Polarstern in late summer 2012, we observed different types of algal aggregates floating underneath various ice types in the Central Arctic basins. We investigated the spatial distribution of ice algal aggregates and quantified their biomass, using under-ice image surveys obtained by an upward-looking camera on a remotely operated vehicle. On basin scale, filamentous aggregates of Melosira arctica are more frequently found in the inner part of the Central Arctic pack ice, while rounded aggregates mainly formed by pennate diatoms are found closer to the ice edge, under melting sea ice. On the scale of an ice floe, the distribution of algal aggregates in late summer is mainly regulated by the topography of the ice underside, with aggregates accumulating in dome-shaped structures and at the edges of pressure ridges. The average biomass of the aggregates from our sites and season was 0.1-6.0 mg C m(-2). However, depending on the approach used, differences in orders of magnitude for biomass estimates may occur. This highlights the difficulties of upscaling observations and comparing results from surveys conducted using different methods or on different spatial scales.

  17. Natural aggregates of the conterminous United States

    USGS Publications Warehouse

    Langer, William H.

    1988-01-01

    Crushed stone and sand and gravel are the two main sources of natural aggregates. These materials are commonly used construction materials and frequently can be interchanged with one another. They are widely used throughout the United States, with every State except two producing crushed stone. Together they amount to about half the mining volume in the United States. Approximately 96 percent of sand and gravel and 77 percent of the crushed stone produced in the United States are used in the construction industry. Natural aggregates are widely distributed throughout the United States in a variety of geologic environments. Sand and gravel deposits commonly are the results of the weathering of bedrock and subsequent transportation and deposition of the material by water or ice (glaciers). As such, they commonly occur as river or stream deposits or in glaciated areas as glaciofluvial and other deposits. Crushed stone aggregates are derived from a wide variety of parent bedrock materials. Limestone and other carbonates account for approximately three quarters of the rocks used for crushed stone, with granite and other igneous rocks making up the bulk of the remainder. Limestone deposits are widespread throughout the Central and Eastern United States and are scattered in the West. Granites are widely distributed in the Eastern and Western United States, with few exposures in the Midwest. Igneous rocks (excluding granites) are largely concentrated in the Western United States and in a few isolated localities in the East. Even though natural aggregates are widely distributed throughout the United States, they are not universally available for consumptive use. Some areas are devoid of sand and gravel, and potential sources of crushed stone may be covered with sufficient unconsolidated material to make surface mining impractical. In some areas many aggregates do not meet the physical property requirements for certain uses, or they may contain mineral constituents that react

  18. Tubular aggregates: their association with myalgia.

    PubMed Central

    Niakan, E; Harati, Y; Danon, M J

    1985-01-01

    Three thousand consecutive muscle biopsies were reviewed for the presence of tubular aggregates and their association with clinical symptomatology. Tubular aggregates were detected in 19 patients (0.6%). Twelve of these nineteen patients had severe myalgia, and the most abundant tubular aggregates were found in biopsies of patients with myalgia. Seven patients had only myalgia as their clinical symptomatology with normal physical examination. An additional five patients with tubular aggregates and myalgia had concomitant amyotrophic lateral sclerosis (2) or neuropathy (3). The high incidence of myalgia associated with tubular aggregates in our patients and the fact that tubular aggregates originate from sarcoplasmic reticulum suggest a role played by this structure in the pathogenesis of myalgia. Images PMID:2995591

  19. Multiscale simulation of red blood cell aggregation

    NASA Astrophysics Data System (ADS)

    Bagchi, P.; Popel, A. S.

    2004-11-01

    In humans and other mammals, aggregation of red blood cells (RBC) is a major determinant to blood viscosity in microcirculation under physiological and pathological conditions. Elevated levels of aggregation are often related to cardiovascular diseases, bacterial infection, diabetes, and obesity. Aggregation is a multiscale phenomenon that is governed by the molecular bond formation between adjacent cells, morphological and rheological properties of the cells, and the motion of the extra-cellular fluid in which the cells circulate. We have developed a simulation technique using front tracking methods for multiple fluids that includes the multiscale characteristics of aggregation. We will report the first-ever direct computer simulation of aggregation of deformable cells in shear flows. We will present results on the effect of shear rate, strength of the cross-bridging bonds, and the cell rheological properties on the rolling motion, deformation and subsequent breakage of an aggregate.

  20. Protein Aggregation Profile of the Bacterial Cytosol

    PubMed Central

    de Groot, Natalia S.; Ventura, Salvador

    2010-01-01

    Background Protein misfolding is usually deleterious for the cell, either as a consequence of the loss of protein function or the buildup of insoluble and toxic aggregates. The aggregation behavior of a given polypeptide is strongly influenced by the intrinsic properties encoded in its sequence. This has allowed the development of effective computational methods to predict protein aggregation propensity. Methodology/Principal Findings Here, we use the AGGRESCAN algorithm to approximate the aggregation profile of an experimental cytosolic Escherichia coli proteome. The analysis indicates that the aggregation propensity of bacterial proteins is associated with their length, conformation, location, function, and abundance. The data are consistent with the predictions of other algorithms on different theoretical proteomes. Conclusions/Significance Overall, the study suggests that the avoidance of protein aggregation in functional environments acts as a strong evolutionary constraint on polypeptide sequences in both prokaryotic and eukaryotic organisms. PMID:20195530

  1. THE EPA REMOTE SENSING ARCHIVE

    EPA Science Inventory

    What would you do if you were faced with organizing 30 years of remote sensing projects that had been haphazardly stored at two separate locations for years then combined? The EPA Remote Sensing Archive, currently located in Las Vegas, Nevada. contains the remote sensing data and...

  2. Remote Sensing: A Film Review.

    ERIC Educational Resources Information Center

    Carter, David J.

    1986-01-01

    Reviews the content of 19 films on remote sensing published between 1973 and 1980. Concludes that they are overly simplistic, notably outdated, and generally too optimistic about the potential of remote sensing from space for resource exploration and environmental problem-solving. Provides names and addresses of more current remote sensing…

  3. Remote Sensing and the Earth.

    ERIC Educational Resources Information Center

    Brosius, Craig A.; And Others

    This document is designed to help senior high school students study remote sensing technology and techniques in relation to the environmental sciences. It discusses the acquisition, analysis, and use of ecological remote data. Material is divided into three sections and an appendix. Section One is an overview of the basics of remote sensing.…

  4. Remote sensing and image interpretation

    NASA Technical Reports Server (NTRS)

    Lillesand, T. M.; Kiefer, R. W. (Principal Investigator)

    1979-01-01

    A textbook prepared primarily for use in introductory courses in remote sensing is presented. Topics covered include concepts and foundations of remote sensing; elements of photographic systems; introduction to airphoto interpretation; airphoto interpretation for terrain evaluation; photogrammetry; radiometric characteristics of aerial photographs; aerial thermography; multispectral scanning and spectral pattern recognition; microwave sensing; and remote sensing from space.

  5. Remotely controllable actuating device

    NASA Technical Reports Server (NTRS)

    McKillip, Jr., Robert M. (Inventor)

    1998-01-01

    An actuating device can change a position of an active member that remains in substantially the same position in the absence of a force of a predetermined magnitude on the active member. The actuating device comprises a shape-memory alloy actuating member for exerting a force when actuated by changing the temperature thereof, which shape-memory alloy actuating member has a portion for connection to the active member for exerting thereon a force having a magnitude at least as large as the predetermined magnitude for moving the active member to a desired position. Actuation circuitry is provided for actuating the shape-memory alloy actuating member by changing the temperature thereof only for the time necessary to move the active member to the desired position. The invention is particularly useful for changing the position of a camber-adjusting tab on a helicopter rotor blade by using two shape-memory alloy members that can act against each other to adjust dynamic properties of the rotor blade as it is rotating.

  6. Aggregative Learning Method and Its Application for Communication Quality Evaluation

    NASA Astrophysics Data System (ADS)

    Akhmetov, Dauren F.; Kotaki, Minoru

    2007-12-01

    In this paper, so-called Aggregative Learning Method (ALM) is proposed to improve and simplify the learning and classification abilities of different data processing systems. It provides a universal basis for design and analysis of mathematical models of wide class. A procedure was elaborated for time series model reconstruction and analysis for linear and nonlinear cases. Data approximation accuracy (during learning phase) and data classification quality (during recall phase) are estimated from introduced statistic parameters. The validity and efficiency of the proposed approach have been demonstrated through its application for monitoring of wireless communication quality, namely, for Fixed Wireless Access (FWA) system. Low memory and computation resources were shown to be needed for the procedure realization, especially for data classification (recall) stage. Characterized with high computational efficiency and simple decision making procedure, the derived approaches can be useful for simple and reliable real-time surveillance and control system design.

  7. Nanoarchitectonics of Molecular Aggregates: Science and Technology

    SciTech Connect

    Ramanathan, Nathan Muruganathan; Hong, Kunlun; Ji, Dr. Qingmin; Hill, Dr. Jonathan P; Ariga, Katsuhiko; Yusuke, Yonamine

    2014-01-01

    The field of making, studying and using molecular aggregates, in which the individual molecules (monomers) are arranged in a regular fashion, has come a long way. Taking control over the aggregation of small molecules and polymers in bulk, on surfaces and at interfaces pose a considerable challenge for their utilization in modern high tech applications. In this review we provide a detailed insight into recent trends in molecular aggregates from the perspectives of nanoarchitectonics.

  8. Aggregates in the Temporal Query Language TQuel,

    DTIC Science & Technology

    1987-07-27

    makes it possible to define both standard and unique aggregates in a rigorous way. Ceri and Gottlob present 43 prVPW t TW WRJR V P P V * a translation...from a subset of SQL that includes aggregates into relational algebra, thereby defining an operational semantics for SQL aggregates [Ceri & Gottlob ...Zvi, J. The Time Relational Model. Ph). Diss. Computer Science Department, UCLA, 1982. (Ceri & Gotlob 19851 Ceri, S. and G. Gottlob . Translating SQL

  9. Immunological memory is associative

    SciTech Connect

    Smith, D.J.; Forrest, S.; Perelson, A.S.

    1996-12-31

    The purpose of this paper is to show that immunological memory is an associative and robust memory that belongs to the class of sparse distributed memories. This class of memories derives its associative and robust nature by sparsely sampling the input space and distributing the data among many independent agents. Other members of this class include a model of the cerebellar cortex and Sparse Distributed Memory (SDM). First we present a simplified account of the immune response and immunological memory. Next we present SDM, and then we show the correlations between immunological memory and SDM. Finally, we show how associative recall in the immune response can be both beneficial and detrimental to the fitness of an individual.

  10. Flexible Kernel Memory

    PubMed Central

    Nowicki, Dimitri; Siegelmann, Hava

    2010-01-01

    This paper introduces a new model of associative memory, capable of both binary and continuous-valued inputs. Based on kernel theory, the memory model is on one hand a generalization of Radial Basis Function networks and, on the other, is in feature space, analogous to a Hopfield network. Attractors can be added, deleted, and updated on-line simply, without harming existing memories, and the number of attractors is independent of input dimension. Input vectors do not have to adhere to a fixed or bounded dimensionality; they can increase and decrease it without relearning previous memories. A memory consolidation process enables the network to generalize concepts and form clusters of input data, which outperforms many unsupervised clustering techniques; this process is demonstrated on handwritten digits from MNIST. Another process, reminiscent of memory reconsolidation is introduced, in which existing memories are refreshed and tuned with new inputs; this process is demonstrated on series of morphed faces. PMID:20552013

  11. Supporting shared data structures on distributed memory architectures

    NASA Technical Reports Server (NTRS)

    Koelbel, Charles; Mehrotra, Piyush; Vanrosendale, John

    1990-01-01

    Programming nonshared memory systems is more difficult than programming shared memory systems, since there is no support for shared data structures. Current programming languages for distributed memory architectures force the user to decompose all data structures into separate pieces, with each piece owned by one of the processors in the machine, and with all communication explicitly specified by low-level message-passing primitives. A new programming environment is presented for distributed memory architectures, providing a global name space and allowing direct access to remote parts of data values. The analysis and program transformations required to implement this environment are described, and the efficiency of the resulting code on the NCUBE/7 and IPSC/2 hypercubes are described.

  12. Memory access in shared virtual memory

    SciTech Connect

    Berrendorf, R. )

    1992-01-01

    Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

  13. Memory access in shared virtual memory

    SciTech Connect

    Berrendorf, R.

    1992-09-01

    Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

  14. Stochastic memory: memory enhancement due to noise.

    PubMed

    Stotland, Alexander; Di Ventra, Massimiliano

    2012-01-01

    There are certain classes of resistors, capacitors, and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by TiO(2) thin films sandwiched between metallic electrodes and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.

  15. Stochastic memory: Memory enhancement due to noise

    NASA Astrophysics Data System (ADS)

    Stotland, Alexander; di Ventra, Massimiliano

    2012-01-01

    There are certain classes of resistors, capacitors, and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by TiO2 thin films sandwiched between metallic electrodes and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.

  16. Quantifying aggregation dynamics during Myxococcus xanthus development.

    PubMed

    Zhang, Haiyang; Angus, Stuart; Tran, Michael; Xie, Chunyan; Igoshin, Oleg A; Welch, Roy D

    2011-10-01

    Under starvation conditions, a swarm of Myxococcus xanthus cells will undergo development, a multicellular process culminating in the formation of many aggregates called fruiting bodies, each of which contains up to 100,000 spores. The mechanics of symmetry breaking and the self-organization of cells into fruiting bodies is an active area of research. Here we use microcinematography and automated image processing to quantify several transient features of developmental dynamics. An analysis of experimental data indicates that aggregation reaches its steady state in a highly nonmonotonic fashion. The number of aggregates rapidly peaks at a value 2- to 3-fold higher than the final value and then decreases before reaching a steady state. The time dependence of aggregate size is also nonmonotonic, but to a lesser extent: average aggregate size increases from the onset of aggregation to between 10 and 15 h and then gradually decreases thereafter. During this process, the distribution of aggregates transitions from a nearly random state early in development to a more ordered state later in development. A comparison of experimental results to a mathematical model based on the traffic jam hypothesis indicates that the model fails to reproduce these dynamic features of aggregation, even though it accurately describes its final outcome. The dynamic features of M. xanthus aggregation uncovered in this study impose severe constraints on its underlying mechanisms.

  17. Population balance modeling of antibodies aggregation kinetics.

    PubMed

    Arosio, Paolo; Rima, Simonetta; Lattuada, Marco; Morbidelli, Massimo

    2012-06-21

    The aggregates morphology and the aggregation kinetics of a model monoclonal antibody under acidic conditions have been investigated. Growth occurs via irreversible cluster-cluster coagulation forming compact, fractal aggregates with fractal dimension of 2.6. We measured the time evolution of the average radius of gyration, , and the average hydrodynamic radius, , by in situ light scattering, and simulated the aggregation kinetics by a modified Smoluchowski's population balance equations. The analysis indicates that aggregation does not occur under diffusive control, and allows quantification of effective intermolecular interactions, expressed in terms of the Fuchs stability ratio (W). In particular, by introducing a dimensionless time weighed on W, the time evolutions of measured under various operating conditions (temperature, pH, type and concentration of salt) collapse on a single master curve. The analysis applies also to data reported in the literature when growth by cluster-cluster coagulation dominates, showing a certain level of generality in the antibodies aggregation behavior. The quantification of the stability ratio gives important physical insights into the process, including the Arrhenius dependence of the aggregation rate constant and the relationship between monomer-monomer and cluster-cluster interactions. Particularly, it is found that the reactivity of non-native monomers is larger than that of non-native aggregates, likely due to the reduction of the number of available hydrophobic patches during aggregation.

  18. A competitive aggregation model for flash nanoprecipitation.

    PubMed

    Cheng, Janine Chungyin; Vigil, R D; Fox, R O

    2010-11-15

    Flash NanoPrecipitation (FNP) is a novel approach for producing functional nanoparticles stabilized by amphiphilic block copolymers. FNP involves the rapid mixing of a hydrophobic active (organic) and an amphiphilic di-block copolymer with a non-solvent (water) and subsequent co-precipitation of nanoparticles composed of both the organic and copolymer. During this process, the particle size distribution (PSD) is frozen and stabilized by the hydrophilic portion of the amphiphilic di-block copolymer residing on the particle surface. That is, the particle growth is kinetically arrested and thus a narrow PSD can be attained. To model the co-precipitation process, a bivariate population balance equation (PBE) has been formulated to account for the competitive aggregation of the organic and copolymer versus pure organic-organic or copolymer-copolymer aggregation. Aggregation rate kernels have been derived to account for the major aggregation events: free coupling, unimer insertion, and aggregate fusion. The resulting PBE is solved both by direct integration and by using the conditional quadrature method of moments (CQMOM). By solving the competitive aggregation model under well-mixed conditions, it is demonstrated that the PSD is controlled primarily by the copolymer-copolymer aggregation process and that the energy barrier to aggregate fusion plays a key role in determining the PSD. It is also shown that the characteristic aggregation times are smaller than the turbulent mixing time so that the FNP process is always mixing limited.

  19. Microbial aggregates in anaerobic wastewater treatment.

    PubMed

    Kosaric, N; Blaszczyk, R

    1990-01-01

    The phenomenon aggregation of anaerobic bacteria gives an opportunity to speed up the digestion rate during methanogenesis. The aggregates are mainly composed of methanogenic bacteria which convert acetate and H2/CO2 into methane. Other bacteria are also included in the aggregates but their concentration is rather small. The aggregates may also be formed during acetogenesis or even hydrolysis but such aggregates are not stable and disrupt quickly when not fed. A two stage process seems to be suitable when high concentrated solid waste must be treated. Special conditions are necessary to promote aggregate formation from methanogenic bacteria but aggregates once formed are stable without feeding even for a few years. The structure, texture and activity of bacterial aggregates depend on several parameters: (1)--temperature and pH, (2)--wastewater composition and (3)--hydrodynamic conditions within the reactor. The common influence of all these parameters is still rather unknown but some recommendations may be given. Temperature and pH should be maintained in the range which is optimal for methanogenic bacteria e.g. a temperature between 32 and 50 degrees C and a value pH between 6.5 and 7.5. Wastewaters should contain soluble wastes and the specific loading rate should be around one kgCOD(kgVSS)-1 d-1. The concentration of the elements influences aggregate composition and probably structure and texture. At high calcium concentration a change in the colour of the granules has been observed. Research is necessary to investigate the influence of other elements and organic toxicants on maintenance of the aggregates. Hydrodynamic conditions seem to influence the stability of the granules over long time periods. At low liquid stream rates, aggregates may starve and lysis within the aggregates is possible which results in hollowing of aggregates and their floating. At high liquid stream rates the aggregates may be disrupted and washed out of the reactor as a flocculent

  20. Familial aggregation analysis of gene expressions

    PubMed Central

    Rao, Shao-Qi; Xu, Liang-De; Zhang, Guang-Mei; Li, Xia; Li, Lin; Shen, Gong-Qing; Jiang, Yang; Yang, Yue-Ying; Gong, Bin-Sheng; Jiang, Wei; Zhang, Fan; Xiao, Yun; Wang, Qing K

    2007-01-01

    Traditional studies of familial aggregation are aimed at defining the genetic (and non-genetic) causes of a disease from physiological or clinical traits. However, there has been little attempt to use genome-wide gene expressions, the direct phenotypic measures of genes, as the traits to investigate several extended issues regarding the distributions of familially aggregated genes on chromosomes or in functions. In this study we conducted a genome-wide familial aggregation analysis by using the in vitro cell gene expressions of 3300 human autosome genes (Problem 1 data provided to Genetic Analysis Workshop 15) in order to answer three basic genetics questions. First, we investigated how gene expressions aggregate among different types (degrees) of relative pairs. Second, we conducted a bioinformatics analysis of highly familially aggregated genes to see how they are distributed on chromosomes. Third, we performed a gene ontology enrichment test of familially aggregated genes to find evidence to support their functional consensus. The results indicated that 1) gene expressions did aggregate in families, especially between sibs. Of 3300 human genes analyzed, there were a total of 1105 genes with one or more significant (empirical p < 0.05) familial correlation; 2) there were several genomic hot spots where highly familially aggregated genes (e.g., the chromosome 6 HLA genes cluster) were clustered; 3) as we expected, gene ontology enrichment tests revealed that the 1105 genes were aggregating not only in families but also in functional categories. PMID:18466548

  1. Single molecule force spectroscopy of asphaltene aggregates.

    PubMed

    Long, Jun; Xu, Zhenghe; Masliyah, Jacob H

    2007-05-22

    Asphaltene aggregation and deposition cause severe problems in nearly all phases of petroleum processing. To resolve those problems, understanding the aggregation mechanisms is a prerequisite and has attracted the interest of a great number of investigators. However, to date, the nature and extent of asphaltene aggregation remain widely debated. In the present study, we attempt to investigate asphaltene aggregation from a completely new perspective. The technique of single molecule force spectroscopy (SMFS) was used to investigate the response of single asphaltene aggregates under an external pulling force. Force curves representing the stretching of single asphaltene aggregates were obtained in simple electrolyte solutions (KCl and calcium) and organic solvents (toluene and heptane). These force curves were well-fitted by the modified worm-like chain model, indicating that those asphaltene aggregates acted like long-chain polymers under pulling by an external force. It was found that lower solution pH values and the presence of divalent cations resulted in a lower bending rigidity of the formed aggregates. The information retrieved from the force curves suggests that asphaltene molecules with a structure featuring small aromatic clusters connected by aliphatic chains do exist and that asphaltene aggregation could occur through a linear polymerization mechanism. The current study extends the application scope of SMFS.

  2. Macroeconomic susceptibility, inflation, and aggregate supply

    NASA Astrophysics Data System (ADS)

    Hawkins, Raymond J.

    2017-03-01

    We unify aggregate-supply dynamics as a time-dependent susceptibility-mediated relationship between inflation and aggregate economic output. In addition to representing well various observations of inflation-output dynamics this parsimonious formalism provides a straightforward derivation of popular representations of aggregate-supply dynamics and a natural basis for economic-agent expectations as an element of inflation formation. Our formalism also illuminates questions of causality and time-correlation that challenge central banks for whom aggregate-supply dynamics is a key constraint in their goal of achieving macroeconomic stability.

  3. Neuronal aggregates: formation, clearance and spreading

    PubMed Central

    Lim, Junghyun; Yue, Zhenyu

    2015-01-01

    Summary Proteostasis is maintained by multiple cellular pathways, including protein synthesis, quality control and degradation. An imbalance of neuronal proteostasis, associated with protein misfolding and aggregation, leads to proteinopathies or neurodegeneration. While genetic variations and protein modifications contribute to aggregate formation, components of the proteostasis network dictate the fate of protein aggregates. Here we provide an overview of proteostasis pathways and their interplay (particularly autophagy) with the metabolism of disease-related proteins. We review recent studies on neuronal activity-mediated regulation of proteostasis and transcellular propagation of protein aggregates in the nervous system. Targeting proteostasis pathways therapeutically remains an attractive but challenging task. PMID:25710535

  4. RBC aggregation: laboratory data and models.

    PubMed

    Meiselman, H J; Neu, B; Rampling, M W; Baskurt, O K

    2007-01-01

    The reversible aggregation of red blood cells (RBC) into linear and three-dimensional structures continues to be of basic science and clinical interest: RBC aggregation affects low shear blood viscosity and microvascular flow dynamics, and can be markedly enhanced in several clinical states. Until fairly recently, most research efforts were focused on relations between suspending medium composition (i.e., protein levels, polymer type and concentration) and aggregate formation. However, there is now an increasing amount of experimental evidence indicating that RBC cellular properties can markedly affect aggregation, with the term "RBC aggregability" coined to describe the cell's intrinsic tendency to aggregate. Variations of aggregability can be large, with some changes of aggregation substantially greater than those resulting from pathologic states. The present review provides a brief overview of this topic, and includes such areas as donor-to-donor variations, polymer-plasma correlations, effects of RBC age, effects of enzymatic treatment, and current developments related to the mechanisms involved in RBC aggregation.

  5. Hemodynamic effects of red blood cell aggregation.

    PubMed

    Baskurt, Oguz K; Meiselman, Herbert J

    2007-01-01

    The influence of red blood cell (RBC) aggregation on blood flow in vivo has been under debate since early 1900's, yet a full understanding has still has not been reached. Enhanced RBC aggregation is well known to increase blood viscosity measured in rotational viscometers. However, it has been demonstrated that RBC aggregation may decrease flow resistance in cylindrical tubes, due to the formation of a cell-poor zone near the tube wall which results from the enhanced central accumulation of RBC. There is also extensive discussion regarding the effects of RBC aggregation on in vivo blood flow resistance. Several groups have reported increased microcirculatory flow resistance with enhanced RBC aggregation in experiments that utilized intravital microscopy. Alternatively, whole organ studies revealed that flow resistance may be significantly decreased if RBC aggregation is enhanced. Recently, new techniques have been developed to achieve well-controlled, graded alterations in RBC aggregation without influencing suspending phase properties. Studies using this technique revealed that the effects of RBC aggregation are determined by the degree of aggregation changes, and that this relationship can be explained by different hemodynamic mechanisms.

  6. Aggregate growth in a protoplanetary disk

    NASA Astrophysics Data System (ADS)

    Xiang, Chuchu; Carballido, Augusto; Matthews, Lorin; Hyde, Truell

    2017-01-01

    We present a method to model the growth of neutral and charged dusts in a turbulent protoplanetary disk, and analyze their collision probabilities. Coagulation of dust aggregates plays an important role in the formation of planets and is of key importance to the evolution of protoplanetary disks. In our method, the temporal evolution of the dusts is followed by Monte Carlo algorithm, and the inter-particle interactions are calculated by Aggregate_Builder (AB), which is a code used to model the collision process of aggregates. First an aggregate library is built and all the aggregates are binned according to their sizes. In each iteration, the collision rate for aggregates from any two bins are computed, which determines the time it takes for the next collision to happen and which two aggregates are selected for collision. Then the AB codes are used to calculate the interaction of the two aggregates. The relative velocity between the two aggregates is the vector sum of Brownian velocity and the turbulent velocity. The latter is calculated by ATHENA, which is a grid-based code for astrophysical magnetohydrodynamics. In each iteration, it’s determined whether the two aggregates hit or miss. In the case of hit, it either sticks or bounces as determined by the critical velocity. As a result, the neutral aggregates are more porous than the charged ones. For a certain size of incoming aggregates, the neutral ones have a higher collision probability than the charged ones. Also, similarly-sized aggregates have lower collision probabilities than aggregates with large size dispersions. This research enables us to determine which physical properties have a greater impact on the collision rate. By tracing the dust size distribution, we can identify the stage when they settle out to the mid-plane and how long it takes to develop to that stage. In the hit-stick regime, our results are consistent with the experiments which shows that when the velocity is smaller than the

  7. Collisional Aggregation Due to Turbulence

    NASA Astrophysics Data System (ADS)

    Pumir, Alain; Wilkinson, Michael

    2016-03-01

    Collisions between particles suspended in a fluid play an important role in many physical processes. As an example, collisions of microscopic water droplets in clouds are a necessary step in the production of macroscopic raindrops. Collisions of dust grains are also conjectured to be important for planet formation in the gas surrounding young stars and to play a role in the dynamics of sand storms. In these processes, collisions are favored by fast turbulent motions. Here we review recent advances in the understanding of collisional aggregation due to turbulence. We discuss the role of fractal clustering of particles and caustic singularities of their velocities. We also discuss limitations of the Smoluchowski equation for modeling such processes. These advances lead to a semiquantitative understanding on the influence of turbulence on collision rates and point to deficiencies in the current understanding of rainfall and planet formation.

  8. Swarms: Optimum aggregations of spacecraft

    NASA Technical Reports Server (NTRS)

    Mayer, H. L.

    1980-01-01

    Swarms are aggregations of spacecraft or elements of a space system which are cooperative in function, but physically isolated or only loosely connected. For some missions the swarm configuration may be optimum compared to a group of completely independent spacecraft or a complex rigidly integrated spacecraft or space platform. General features of swarms are induced by considering an ensemble of 26 swarms, examples ranging from Earth centered swarms for commercial application to swarms for exploring minor planets. A concept for a low altitude swarm as a substitute for a space platform is proposed and a preliminary design studied. The salient design feature is the web of tethers holding the 30 km swarm in a rigid two dimensional array in the orbital plane. A mathematical discussion and tutorial in tether technology and in some aspects of the distribution of services (mass, energy, and information to swarm elements) are included.

  9. Thrombolytic therapy reduces red blood cell aggregation in plasma without affecting intrinsic aggregability.

    PubMed

    Ben-Ami, R; Sheinman, G; Yedgar, S; Eldor, A; Roth, A; Berliner, A S; Barshtein, G

    2002-03-15

    Red blood cell (RBC) aggregation may contribute to occlusion of the coronary microcirculation during myocardial infarction. We studied the effect of thrombolytic therapy on RBC aggregation in patients with acute myocardial infarction (AMI). Compared with patients with myocardial infarction who did not receive thrombolytic therapy, those treated with systemic thrombolysis exhibited significantly reduced RBC aggregation, reduced plasma fibrinogen levels and increased plasma D-dimer levels. Using measurement of RBC aggregation in a standardized dextran-500 solution, reduction in RBC aggregation after thrombolysis was shown to be plasma dependent. Thrombolytic therapy had no direct effect on intrinsic RBC aggregability in patients with AMI. We conclude that thrombolytic therapy has rheologic consequences that may contribute to its overall efficacy. Inhibition of RBC aggregation by thrombolytic therapy may result from the degradation of fibrinogen, a key factor in the formation of RBC aggregates, and from the generation of fibrinogen degradation products capable of disaggregating RBCs.

  10. Autobiographical and episodic memory deficits in mild traumatic brain injury.

    PubMed

    Wammes, Jeffrey D; Good, Tyler J; Fernandes, Myra A

    2017-02-01

    Those who have suffered a concussion, otherwise known as a mild traumatic brain injury (mTBI), often complain of lingering memory problems. However, there is little evidence in the behavioral literature reliably demonstrating memory deficits. Thus, in the present study, cognitive profiles including measures of general executive functioning and processing speed, as well as episodic and semantic memory were collected in younger and older adult participants with or without a remote (>1year prior to testing) mTBI. We first investigated whether there were observable episodic and autobiographical memory impairments associated with mTBI within an otherwise healthy young group. Next, because previous work had demonstrated some overlap in patterns of behavioral impairment in normally aging adults and younger adults with a history of mTBI (e.g. Ozen, Fernandes, Clark, & Roy, 2015), we sought to determine whether these groups displayed similar cognitive profiles. Lastly, we conducted an exploratory analysis to test whether having suffered an mTBI might exacerbate age-related cognitive decline. Results showed the expected age-related decline in episodic memory performance, coupled with a relative preservation of semantic memory in older adults. Importantly, this pattern was also present in younger adults with a history of remote mTBI. No differences were observed across older adult groups based on mTBI status. Logistic regression analyses, using each measure in our battery as a predictor, successfully classified mTBI status in younger participants with a high degree of specificity (79.5%). These results indicate that those who have had an mTBI demonstrate a distinct cognitive signature, characterized by impairment in episodic and autobiographical memory, coupled with a relative preservation of semantic memory.

  11. Remote sensing for land management and planning

    NASA Astrophysics Data System (ADS)

    Woodcock, Curtis E.; Strahler, Alan H.; Franklin, Janet

    1983-05-01

    The primary role of remote sensing in land management and planning has been to provide information concerning the physical characteristics of the land which influence the management of individual land parcels or the allocation of lands to various uses These physical characteristics have typically been assessed through aerial photography, which is used to develop resource maps and to monitor changing environmental conditions These uses are well developed and currently well integrated into the planning infrastructure at local, state, and federal levels in the United States. Many newly emerging uses of remote sensing involve digital images which are collected, stored, and processed automatically by electromechanical scanning devices and electronic computers Some scanning devices operate from aircraft or spacecraft to scan ground scenes directly; others scan conventional aerial transparencies to yield digital images. Digital imagery offers the potential for computer-based automated map production, a process that can significantly increase the amount and timeliness of information available to land managers and planners. Future uses of remote sensing in land planning and management will involve geographic information systems, which store resource information in a geocoded format. Geographic information systems allow the automated integration of disparate types of resource data through various types of spatial models so that with accompanying sample ground data, information in the form of thematic maps and/ or aerially aggregated statistics can be produced Key issues confronting the development and integration of geographic information systems into planning pathways are restoration and rectification of digital images, automated techniques for combining both quantitative and qualitative types of data in information-extracting procedures, and the compatibility of alternative data storage modes

  12. CA1 neurons in the human hippocampus are critical for autobiographical memory, mental time travel, and autonoetic consciousness

    PubMed Central

    Bartsch, Thorsten; Döhring, Juliane; Rohr, Axel; Jansen, Olav; Deuschl, Günther

    2011-01-01

    Autobiographical memories in our lives are critically dependent on temporal lobe structures. However, the contribution of CA1 neurons in the human hippocampus to the retrieval of episodic autobiographical memory remains elusive. In patients with a rare acute transient global amnesia, highly focal lesions confined to the CA1 field of the hippocampus can be detected on MRI. We studied the effect of these lesions on autobiographical memory using a detailed autobiographical interview including the remember/know procedure. In 14 of 16 patients, focal lesions in the CA1 sector of the hippocampal cornu ammonis were detected. Autobiographical memory was significantly affected over all time periods, including memory for remote periods. Impairment of episodic memory and autonoetic consciousness exhibited a strong temporal gradient extending 30 to 40 y into the past. These results highlight the distinct and critical role of human hippocampal CA1 neurons in autobiographical memory retrieval and for re-experiencing detailed episodic memories. PMID:21987814

  13. Optogenetic Induction of Aversive Taste Memory

    PubMed Central

    C. Keene, Alex; Masek, Pavel

    2013-01-01

    The Drosophila melanogaster gustatory system consists of several neuronal pathways representing diverse taste modalities. The two predominant modalities are a sweet sensing pathway that mediates attraction, and a bitter sensing pathway that mediates avoidance. A central question is how flies integrate stimuli from these pathways and generate the appropriate behavioral response. We have developed a novel assay for induction of taste memories. We demonstrate that the gustatory response to fructose is suppressed when followed by the presence of bitter quinine. We employ optogenetic neural activation using infrared laser in combination with heat sensitive channel - TRPA1 to precisely activate gustatory neurons. This optogenetic system allows for spatially and temporally controlled activation of distinct neural classes in the gustatory circuit. We directly activated bitter-sensing neurons together with presentation of fructose for remote induction of aversive taste memories. Here we report that activation of bitter-sensing neurons in the proboscis suffices as a conditioning stimulus. Spatially restricted stimulation indicates that the conditioning stimulus is indeed a signal from the bitter neurons in the proboscis and it is independent of postingestive feedback. The coincidence of temporally specific activation of bitter-sensing neurons with fructose presentation is crucial for memory formation, establishing aversive taste learning in Drosophila as associative learning. Taken together, this optogenetic system provides a powerful new tool for interrogation of the central brain circuits that mediate memory formation. PMID:22820051

  14. Aggregation and disaggregation of radar rainfall rates

    NASA Astrophysics Data System (ADS)

    Krebsbach, K.; Friederichs, P.

    2012-12-01

    Spatially distributed, high-resolution precipitation rates are key ingredients for modeling soil-vegetation processes, water and solute transports in mesoscale catchments, and for short-range weather prediction. The ultimate goal of our study is to develop a space-time, multilevel statistical model that merges rain radar measurements with other observations of precipitation. This is a challenging task since it aims at combining data sources with a variety of error structures, and temporal resolutions. E.g., in-situ measurements are quite accurate, but available only at sparse and irregularly distributed locations, whereas remote measurements cover complete areas but suffer from spatially and temporally inhomogeneous systematic errors. The first step towards such a space-time precipitation model is to develop a statistical model for precipitation based on radar measurements. Precipitation rates over a region of about 230× 230 km2 are provided by a composite of the two polarimetric X-band radars in Germany. The two radars are located in a distance of about 60 km in Bonn and Jülich, respectively. For the statistical model formulation we use a Gaussian Markov random field as underlying process. A Markov random field is a suitable model to account for spatial dependencies if the neighborhood can be reduced to a small region without losing information. This makes large data problems computationally feasible, since the neighborhood structure is given by a sparse precision matrix. Markov random fields are closely related to a graphical models. In processing the unadjusted radar rainfall rates, we follow D. Allcroft and C. Glasbey (2003)footnote{⪉bel{foot:1}David Allcroft and Chris Glasbey (2003). A latent Gaussian Markov Random Field model for spatiotemporal rainfall disaggregationJournal of the Royal Statistical Society: Series C (Applied Statistics), 52:487-498}. We start with a transformation of the precipitation rates to a truncated Gaussian distribution. The

  15. Memory bistable mechanisms of organic memory devices

    NASA Astrophysics Data System (ADS)

    Lee, Ching-Ting; Yu, Li-Zhen; Chen, Hung-Chun

    2010-07-01

    To investigate the memory bistable mechanisms of organic memory devices, the structure of [top Au anode/9,10-di(2-naphthyl)anthracene (ADN) active layer/bottom Au cathode] was deposited using a thermal deposition system. The Au atoms migrated into the ADN active layer was observed from the secondary ion mass spectrometry. The density of 9.6×1016 cm-3 and energy level of 0.553 eV of the induced trapping centers caused by the migrated Au atoms in the ADN active layer were calculated. The induced trapping centers did not influence the carrier injection barrier height between Au and ADN active layer. Therefore, the memory bistable behaviors of the organic memory devices were attributed to the induced trapping centers. The energy diagram was established to verify the mechanisms.

  16. Temporally remote destabilization of prediction after rare breaches of expectancy.

    PubMed

    Kühn, Anne B; Schubotz, Ricarda I

    2012-08-01

    While neural signatures of breaches of expectancy and their immediate effects have been investigated, thus far, temporally more remote effects have been neglected. The present fMRI study explored neural correlates of temporally remote destabilization of prediction following rare breaches of expectancy with a mean delay of 14 s. We hypothesized temporally remote destabilization to be reflected either in an attenuation of areas related to long-term memory or in an increase of lateral fronto-parietal loops related to the encoding of new stimuli. Monitoring a deterministic 24-digit sequence, subjects were asked to indicate occasional sequential omissions by key press. Temporally remote destabilization of prediction was expected to be revealed by contrasting sequential events whose equivalent was omitted in the preceding sequential run n-1 (destabilized events) with sequential events without such history (nondestabilized events). Temporally remote destabilization of prediction was reflected in an attenuation of activity in the dorsal frontomedian cortex (Brodmann Area (BA) 9) bilaterally. Moreover, activation of the left medial BA 9 was enhanced by contrasting nondestabilized events with breaches. The decrease of dorsal frontomedian activation in the case of destabilized events might be interpreted as a top-down modulation on perception causing a less expectation-restricted encoding of the current stimulus and hence enabling the adaptation of expectation and prediction in the long run.

  17. Remote sensing of Earth terrain

    NASA Technical Reports Server (NTRS)

    Kong, J. A.

    1993-01-01

    Progress report on remote sensing of Earth terrain covering the period from Jan. to June 1993 is presented. Areas of research include: radiative transfer model for active and passive remote sensing of vegetation canopy; polarimetric thermal emission from rough ocean surfaces; polarimetric passive remote sensing of ocean wind vectors; polarimetric thermal emission from periodic water surfaces; layer model with tandom spheriodal scatterers for remote sensing of vegetation canopy; application of theoretical models to active and passive remote sensing of saline ice; radiative transfer theory for polarimetric remote sensing of pine forest; scattering of electromagnetic waves from a dense medium consisting of correlated mie scatterers with size distributions and applications to dry snow; variance of phase fluctuations of waves propagating through a random medium; polarimetric signatures of a canopy of dielectric cylinders based on first and second order vector radiative transfer theory; branching model for vegetation; polarimetric passive remote sensing of periodic surfaces; composite volume and surface scattering model; and radar image classification.

  18. Flow Partitioning in Fully Saturated Soil Aggregates

    SciTech Connect

    Yang, Xiaofan; Richmond, Marshall C.; Scheibe, Timothy D.; Perkins, William A.; Resat, Haluk

    2014-03-30

    Microbes play an important role in facilitating organic matter decomposition in soils, which is a major component of the global carbon cycle. Microbial dynamics are intimately coupled to environmental transport processes, which control access to labile organic matter and other nutrients that are needed for the growth and maintenance of microorganisms. Transport of soluble nutrients in the soil system is arguably most strongly impacted by preferential flow pathways in the soil. Since the physical structure of soils can be characterized as being formed from constituent micro aggregates which contain internal porosity, one pressing question is the partitioning of the flow among the “inter-aggregate” and “intra-aggregate” pores and how this may impact overall solute transport within heterogeneous soil structures. The answer to this question is particularly important in evaluating assumptions to be used in developing upscaled simulations based on highly-resolved mechanistic models. We constructed a number of diverse multi-aggregate structures with different packing ratios by stacking micro-aggregates containing internal pores and varying the size and shape of inter-aggregate pore spacing between them. We then performed pore-scale flow simulations using computational fluid dynamics methods to determine the flow patterns in these aggregate-of-aggregates structures and computed the partitioning of the flow through intra- and inter-aggregate pores as a function of the spacing between the aggregates. The results of these numerical experiments demonstrate that soluble nutrients are largely transported via flows through inter-aggregate pores. Although this result is consistent with intuition, we have also been able to quantify the relative flow capacity of the two domains under various conditions. For example, in our simulations, the flow capacity through the aggregates (intra-aggregate flow) was less than 2% of the total flow when the spacing between the aggregates

  19. Acetal phosphatidic acids: novel platelet aggregating agents.

    PubMed

    Brammer, J P; Maguire, M H; Walaszek, E J; Wiley, R A

    1983-05-01

    1 Palmitaldehyde, olealdehyde and linolealdehyde acetal phosphatidic acids induced rapid shape change and dose-dependent biphasic aggregation of human platelets in platelet-rich plasma; aggregation was reversible at low doses and irreversible at high doses of the acetal phosphatidic acids. The palmitaldehyde congener elicited monophasic dose-dependent aggregation of sheep platelets in platelet-rich plasma.2 The threshold concentration for palmitaldehyde acetal phosphatidic acid (PGAP)-induced platelet aggregation was 2.5-5 muM for human platelets and 0.25-0.5 muM for sheep platelets. PGAP was 4-5 times as potent versus human platelets as the olealdehyde and linolealdehyde acetal phosphatidic acids, which were equipotent.3 PGAP-induced irreversible aggregation of [(14)C]-5-hydroxytryptamine ([(14)C]-5-HT)-labelled human platelets in platelet-rich plasma was accompanied by release of 44.0+/-2.4% (s.e.) of the platelet [(14)C]-5-HT; reversible aggregation was not associated with release. In contrast, PGAP-induced release of [(14)C]-5-HT-labelled sheep platelets was dose-dependent.4 The adenosine diphosphate (ADP) antagonist, 2-methylthio-AMP, and the cyclo-oxygenase inhibitor, aspirin, abolished PGAP-induced second phase aggregation and release in human platelets but did not affect the first, reversible, phase of aggregation. Both the first and second phases of PGAP-induced aggregation were abolished by chlorpromazine, by the phospholipase A(2) inhibitor, mepacrine, and by nmolar concentrations of prostaglandin E(1) (PGE(1)); these agents abolished the second, but not the first phase of ADP-induced aggregation.5 The related phospholipids, lecithin, lysolecithin and phosphatidic acid, at <100 muM, neither induced aggregation of human platelets in platelet-rich plasma, nor modified PGAP-induced aggregation; 1-palmityl lysophosphatidic acid elicited aggregation of human platelets at a threshold concentration of 100 muM.6 It is concluded that the acetal phosphatidic acids

  20. Evapotranspiration and remote sensing

    NASA Technical Reports Server (NTRS)

    Schmugge, T. J.; Gurney, R.

    1982-01-01

    There are three things required for evapotranspiration to occur: (1) energy (580 cal/gm) for the change of phase of the water; (2) a source of the water, i.e., adequate soil moisture in the surface layer or in the root zone of the plant; and (3) a sink for the water, i.e., a moisture deficit in the air above the ground. Remote sensing can contribute information to the first two of these conditions by providing estimates of solar insolation, surface albedo, surface temperature, vegetation cover, and soil moisture content. In addition there have been attempts to estimate precipitation and shelter air temperature from remotely sensed data. The problem remains to develop methods for effectively using these sources of information to make large area estimates of evapotranspiration.

  1. Remote Sensing Laboratory - RSL

    ScienceCinema

    None

    2016-07-12

    One of the primary resources supporting homeland security is the Remote Sensing Laboratory, or RSL. The Laboratory creates advanced technologies for emergency response operations, radiological incident response, and other remote sensing activities. RSL emergency response teams are on call 24-hours a day, and maintain the capability to deploy domestically and internationally in response to threats involving the loss, theft, or release of nuclear or radioactive material. Such incidents might include Nuclear Power Plant accidents, terrorist incidents involving nuclear or radiological materials, NASA launches, and transportation accidents involving nuclear materials. Working with the US Department of Homeland Security, RSL personnel equip, maintain, and conduct training on the mobile detection deployment unit, to provide nuclear radiological security at major national events such as the super bowl, the Indianapolis 500, New Year's Eve celebrations, presidential inaugurations, international meetings and conferences, just about any event where large numbers of people will gather.

  2. Remote surface inspection system

    NASA Technical Reports Server (NTRS)

    Hayati, S.; Balaram, J.; Seraji, H.; Kim, W. S.; Tso, K.; Prasad, V.

    1993-01-01

    This paper reports on an on-going research and development effort in remote surface inspection of space platforms such as the Space Station Freedom (SSF). It describes the space environment and identifies the types of damage for which to search. This paper provides an overview of the Remote Surface Inspection System that was developed to conduct proof-of-concept demonstrations and to perform experiments in a laboratory environment. Specifically, the paper describes three technology areas: (1) manipulator control for sensor placement; (2) automated non-contact inspection to detect and classify flaws; and (3) an operator interface to command the system interactively and receive raw or processed sensor data. Initial findings for the automated and human visual inspection tests are reported.

  3. Remote Sensing Laboratory - RSL

    SciTech Connect

    2014-11-06

    One of the primary resources supporting homeland security is the Remote Sensing Laboratory, or RSL. The Laboratory creates advanced technologies for emergency response operations, radiological incident response, and other remote sensing activities. RSL emergency response teams are on call 24-hours a day, and maintain the capability to deploy domestically and internationally in response to threats involving the loss, theft, or release of nuclear or radioactive material. Such incidents might include Nuclear Power Plant accidents, terrorist incidents involving nuclear or radiological materials, NASA launches, and transportation accidents involving nuclear materials. Working with the US Department of Homeland Security, RSL personnel equip, maintain, and conduct training on the mobile detection deployment unit, to provide nuclear radiological security at major national events such as the super bowl, the Indianapolis 500, New Year's Eve celebrations, presidential inaugurations, international meetings and conferences, just about any event where large numbers of people will gather.

  4. Remote optical fiber dosimetry

    NASA Astrophysics Data System (ADS)

    Huston, A. L.; Justus, B. L.; Falkenstein, P. L.; Miller, R. W.; Ning, H.; Altemus, R.

    2001-09-01

    Optical fibers offer a unique capability for remote monitoring of radiation in difficult-to-access and/or hazardous locations. Optical fiber sensors can be located in radiation hazardous areas and optically interrogated from a safe distance. A variety of remote optical fiber radiation dosimetry methods have been developed. All of the methods take advantage of some form of radiation-induced change in the optical properties of materials such as: radiation-induced darkening due to defect formation in glasses, luminescence from native defects or radiation-induced defects, or population of metastable charge trapping centers. Optical attenuation techniques are used to measure radiation-induced darkening in fibers. Luminescence techniques include the direct measurement of scintillation or optical excitation of radiation-induced luminescent defects. Optical fiber radiation dosimeters have also been constructed using charge trapping materials that exhibit thermoluminescence or optically stimulated luminescence (OSL).

  5. Morphological properties of atmospheric aerosol aggregates

    PubMed Central

    Xiong, C.; Friedlander, S. K.

    2001-01-01

    Ultrafine particles (smaller than about 0.1 μm) are often emitted from combustion and other high-temperature processes in the form of fractal-like aggregates composed of solid nanoparticles. Results of a study of atmospheric aggregates are reported. Particles were collected on transmission electron microscope grids fitted on the last two stages of a single-jet eight-stage low-pressure impactor for periods of a few minutes. Photomicrographs of transmission electron microscope grids from the impactor stages were analyzed to obtain the fractal dimension (Df) and prefactor (A) for aggregates. Df increased from near 1 to above 2 as the number of primary particles making up the aggregates increased from 10 to 180. Total particle concentrations in size ranges roughly equivalent to the low-pressure impactor stages were measured with a mobility analyzer and condensation particle counter. In one set of measurements, the fraction of the particles present as aggregates was about 60% for particles with aerodynamic diameters between 50 and 75 nm and 34% for the range 75 to 120 nm. The total aggregate concentration in the 50- to 120-nm size range was about 400 ml−1. The primary particles that make up atmospheric aggregates are more polydisperse than soot aggregates generated from a single laboratory source, an ethane/oxygen flame. Most measurements were made in the Los Angeles area, where the aggregates may represent a signature for diesel emissions. Rural aggregate concentrations in the size range 50 to 120 nm were less than 1% of the concentrations at urban sites. The data will permit better estimates of atmospheric aggregate residence times, transport, and deposition in the lung, optical extinction, and heterogenous nucleation. PMID:11592995

  6. Morphological properties of atmospheric aerosol aggregates.

    PubMed

    Xiong, C; Friedlander, S K

    2001-10-09

    Ultrafine particles (smaller than about 0.1 microm) are often emitted from combustion and other high-temperature processes in the form of fractal-like aggregates composed of solid nanoparticles. Results of a study of atmospheric aggregates are reported. Particles were collected on transmission electron microscope grids fitted on the last two stages of a single-jet eight-stage low-pressure impactor for periods of a few minutes. Photomicrographs of transmission electron microscope grids from the impactor stages were analyzed to obtain the fractal dimension (D(f)) and prefactor (A) for aggregates. D(f) increased from near 1 to above 2 as the number of primary particles making up the aggregates increased from 10 to 180. Total particle concentrations in size ranges roughly equivalent to the low-pressure impactor stages were measured with a mobility analyzer and condensation particle counter. In one set of measurements, the fraction of the particles present as aggregates was about 60% for particles with aerodynamic diameters between 50 and 75 nm and 34% for the range 75 to 120 nm. The total aggregate concentration in the 50- to 120-nm size range was about 400 ml(-1). The primary particles that make up atmospheric aggregates are more polydisperse than soot aggregates generated from a single laboratory source, an ethane/oxygen flame. Most measurements were made in the Los Angeles area, where the aggregates may represent a signature for diesel emissions. Rural aggregate concentrations in the size range 50 to 120 nm were less than 1% of the concentrations at urban sites. The data will permit better estimates of atmospheric aggregate residence times, transport, and deposition in the lung, optical extinction, and heterogeneous nucleation.

  7. Selectivity of aggregation-determining interactions.

    PubMed

    Ganesan, Ashok; Debulpaep, Maja; Wilkinson, Hannah; Van Durme, Joost; De Baets, Greet; Jonckheere, Wim; Ramakers, Meine; Ivarsson, Ylva; Zimmermann, Pascale; Van Eldere, Johan; Schymkowitz, Joost; Rousseau, Frederic

    2015-01-30

    Protein aggregation is sequence specific, favoring self-assembly over cross-seeding with non-homologous sequences. Still, as the majority of proteins in a proteome are aggregation prone, the high level of homogeneity of protein inclusions in vivo both during recombinant overexpression and in disease remains surprising. To investigate the selectivity of protein aggregation in a proteomic context, we here compared the selectivity of aggregation-determined interactions with antibody binding. To that purpose, we synthesized biotin-labeled peptides, corresponding to aggregation-determining sequences of the bacterial protein β-galactosidase and two human disease biomarkers: C-reactive protein and prostate-specific antigen. We analyzed the selectivity of their interactions in Escherichia coli lysate, human serum and human seminal plasma, respectively, using a Western blot-like approach in which the aggregating peptides replace the conventional antibody. We observed specific peptide accumulation in the same bands detected by antibody staining. Combined spectroscopic and mutagenic studies confirmed accumulation resulted from binding of the peptide on the identical sequence of the immobilized target protein. Further, we analyzed the sequence redundancy of aggregating sequences and found that about 90% of them are unique within their proteome. As a result, the combined specificity and low sequence redundancy of aggregating sequences therefore contribute to the observed homogeneity of protein aggregation in vivo. This suggests that these intrinsic proteomic properties naturally compartmentalize aggregation events in sequence space. In the event of physiological stress, this might benefit the ability of cells to respond to proteostatic stress by allowing chaperones to focus on specific aggregation events rather than having to face systemic proteostatic failure.

  8. Preformed Seeds Modulate Native Insulin Aggregation Kinetics.

    PubMed

    Dutta, Colina; Yang, Mu; Long, Fei; Shahbazian-Yassar, Reza; Tiwari, Ashutosh

    2015-12-10

    Insulin aggregates under storage conditions via disulfide interchange reaction. It is also known to form aggregates at the site of repeated injections in diabetes patients, leading to injection amyloidosis. This has fueled research in pharmaceutical and biotechnology industry as well as in academia to understand factors that modulate insulin stability and aggregation. The main aim of this study is to understand the factors that modulate aggregation propensity of insulin under conditions close to physiological and measure effect of "seeds" on aggregation kinetics. We explored the aggregation kinetics of insulin at pH 7.2 and 37 °C in the presence of disulfide-reducing agent dithiothreitol (DTT), using spectroscopy (UV-visible, fluorescence, and Fourier transform infrared spectroscopy) and microscopy (scanning electron microscopy, atomic force microscopy) techniques. We prepared insulin "seeds" by incubating disulfide-reduced insulin at pH 7.2 and 37 °C for varying lengths of time (10 min to 12 h). These seeds were added to the native protein and nucleation-dependent aggregation kinetics was measured. Aggregation kinetics was fastest in the presence of 10 min seeds suggesting they were nascent. Interestingly, intermediate seeds (30 min to 4 h incubation) resulted in formation of transient fibrils in 4 h that converted to amorphous aggregates upon longer incubation of 24 h. Overall, the results show that insulin under disulfide reducing conditions at pH and temperature close to physiological favors amorphous aggregate formation and seed "maturity" plays an important role in nucleation dependent aggregation kinetics.

  9. Remote Minehunting System (RMS)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-286 Remote Minehunting System (RMS) As of FY 2017 President’s Budget Defense Acquisition...Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined TY - Then Year UCR...Analysis was completed and the Original Equipment Manufacturer (OEM) was selected based on the number of vehicles and the repair capabilities

  10. Remote switch actuator

    DOEpatents

    Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan

    2013-01-29

    The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

  11. Remotely Operated Robotic Firefighter

    DTIC Science & Technology

    1988-07-01

    when explosion of ordnance becomes a threat because of fire exposure on an aircraft. Many concepts were investigated to satisfy design criteria... satisfactory . An interim review was conducted on 28 May 1987 to review FDM design, fabrication, and testing. The major components of the remote-controlled...vicinity of the runways and taxiways. (3) Primary Mission Operational Scenarios The Operational Scenarios which satisfy the Primary Mission criteria are

  12. Telemetry remote modules

    NASA Technical Reports Server (NTRS)

    Silverman, J. R.

    1972-01-01

    A fully operational engineering telemetry remote module is reported that forms the basis for a decentralized telemetry system which employs small low powered modules capable of distributing the multiplexer input gates around a spacecraft. The module operates mainly as a harness reducer, allowing data to be transmitted back to a central control core for inclusion in the telemetry bit stream. Each unit is capable of accepting 32 data points in various combinations.

  13. Remote terminal system evaluation

    NASA Technical Reports Server (NTRS)

    Phillips, T. L.; Grams, H. L.; Lindenlaub, J. C.; Schwingendorf, S. K.; Swain, P. H.; Simmons, W. R.

    1975-01-01

    An Earth Resources Data Processing System was developed to evaluate the system for training, technology transfer, and data processing. In addition to the five sites included in this project two other sites were connected to the system under separate agreements. The experience of these two sites is discussed. The results of the remote terminal project are documented in seven reports: one from each of the five project sites, Purdue University, and an overview report summarizing the other six reports.

  14. Internet Based Remote Operations

    NASA Technical Reports Server (NTRS)

    Chamberlain, James

    1999-01-01

    This is the Final Report for the Internet Based Remote Operations Contract, has performed payload operations research support tasks March 1999 through September 1999. These tasks support the GSD goal of developing a secure, inexpensive data, voice, and video mission communications capability between remote payload investigators and the NASA payload operations team in the International Space Station (ISS) era. AZTek has provided feedback from the NASA payload community by utilizing its extensive payload development and operations experience to test and evaluate remote payload operations systems. AZTek has focused on use of the "public Internet" and inexpensive, Commercial-off-the-shelf (COTS) Internet-based tools that would most benefit "small" (e.g., $2 Million or less) payloads and small developers without permanent remote operations facilities. Such projects have limited budgets to support installation and development of high-speed dedicated communications links and high-end, custom ground support equipment and software. The primary conclusions of the study are as follows: (1) The trend of using Internet technology for "live" collaborative applications such as telescience will continue. The GSD-developed data and voice capabilities continued to work well over the "public" Internet during this period. 2. Transmitting multiple voice streams from a voice-conferencing server to a client PC to be mixed and played on the PC is feasible. 3. There are two classes of voice vendors in the market: - Large traditional phone equipment vendors pursuing integration of PSTN with Internet, and Small Internet startups.The key to selecting a vendor will be to find a company sufficiently large and established to provide a base voice-conferencing software product line for the next several years.

  15. Airborne Hyperspectral Remote Sensing

    DTIC Science & Technology

    2016-06-07

    conducted studies of the sediments, seagrass and corals . The objective is to correlate the hyperspectral imagery with the detailed in-situ measurements...seagrass and coral reefs (Mazel, 1998). In addition to the basic science there is a directed effort in remote sensing for seafloor imaging and...area includes different bottom types – coral , sand, seagrass – sometimes within the same local area, at a variety of depths. Most of the region is quite

  16. Remote sensing program

    NASA Technical Reports Server (NTRS)

    Liang, T.

    1973-01-01

    Research projects concerning the development and application of remote sensors are discussed. Some of the research projects conducted are as follows: (1) aerial photographic inventory of natural resources, (2) detection of buried river channels, (3) delineation of interconnected waterways, (4) plant indicators of atmospheric pollution, and (5) techniques for data transfer from photographs to base maps. On-going projects involving earth resources analyses are described.

  17. REMOTELY RECHARGEABLE EPD

    SciTech Connect

    Vrettos, N; Athneal Marzolf, A; Scott Bowser, S

    2007-11-13

    Radiation measurements inside the Contact Decon Maintenance Cell (CDMC) in the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) are required to determine stay times for personnel. A system to remotely recharge the transmitter of an Electronic Personnel Dosimeter (EPD) and bail assembly to transport the EPD within the CDMC was developed by the Savannah River National Laboratory (SRNL) to address this need.

  18. Remote Attitude Measurement Techniques.

    DTIC Science & Technology

    1982-12-01

    Engineering , New Jersey Institute of Technology. Published by University Microfilms International- Plibi R92,3 19. KCEY WORDS (Continue on reverse side...of the sensor is expressed in terms of a probabilistic matrix. The engineering considerations for liplementing a Remote Attitude Measure- ment...doctoral research. While in residence at Ft. Monmouth, the author served as the project engineer on an exploratory development model of a state of the art

  19. Psychophysiology of prospective memory.

    PubMed

    Rothen, Nicolas; Meier, Beat

    2014-01-01

    Prospective memory involves the self-initiated retrieval of an intention upon an appropriate retrieval cue. Cue identification can be considered as an orienting reaction and may thus trigger a psychophysiological response. Here we present two experiments in which skin conductance responses (SCRs) elicited by prospective memory cues were compared to SCRs elicited by aversive stimuli to test whether a single prospective memory cue triggers a similar SCR as an aversive stimulus. In Experiment 2 we also assessed whether cue specificity had a differential influence on prospective memory performance and on SCRs. We found that detecting a single prospective memory cue is as likely to elicit a SCR as an aversive stimulus. Missed prospective memory cues also elicited SCRs. On a behavioural level, specific intentions led to better prospective memory performance. However, on a psychophysiological level specificity had no influence. More generally, the results indicate reliable SCRs for prospective memory cues and point to psychophysiological measures as valuable approach, which offers a new way to study one-off prospective memory tasks. Moreover, the findings are consistent with a theory that posits multiple prospective memory retrieval stages.

  20. Tracking the Time-Dependent Role of the Hippocampus in Memory Recall Using DREADDs

    PubMed Central

    Varela, Carmen; Weiss, Sarah; Meyer, Retsina; Halassa, Michael; Biedenkapp, Joseph; Wilson, Matthew A.; Goosens, Ki Ann

    2016-01-01

    The hippocampus is critical for the storage of new autobiographical experiences as memories. Following an initial encoding stage in the hippocampus, memories undergo a process of systems-level consolidation, which leads to greater stability through time and an increased reliance on neocortical areas for retrieval. The extent to which the retrieval of these consolidated memories still requires the hippocampus is unclear, as both spared and severely degraded remote memory recall have been reported following post-training hippocampal lesions. One difficulty in definitively addressing the role of the hippocampus in remote memory retrieval is the precision with which the entire volume of the hippocampal region can be inactivated. To address this issue, we used Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), a chemical-genetic tool capable of highly specific neuronal manipulation over large volumes of brain tissue. We find that remote (>7 weeks after acquisition), but not recent (1–2 days after acquisition) contextual fear memories can be recalled after injection of the DREADD agonist (CNO) in animals expressing the inhibitory DREADD in the entire hippocampus. Our data demonstrate a time-dependent role of the hippocampus in memory retrieval, supporting the standard model of systems consolidation. PMID:27145133

  1. Impact of Particle Aggregation on Nanoparticle Reactivity

    NASA Astrophysics Data System (ADS)

    Jassby, David

    2011-12-01

    The prevalence of nanoparticles in the environment is expected to grow in the coming years due to their increasing pervasiveness in consumer and industrial applications. Once released into the environment, nanoparticles encounter conditions of pH, salinity, UV light, and other solution conditions that may alter their surface characteristics and lead to aggregation. The unique properties that make nanoparticles desirable are a direct consequence of their size and increased surface area. Therefore, it is critical to recognize how aggregation alters the reactive properties of nanomaterials, if we wish to understand how these properties are going to behave once released into the environment. The size and structure of nanoparticle aggregates depend on surrounding conditions, including hydrodynamic ones. Depending on these conditions, aggregates can be large or small, tightly packed or loosely bound. Characterizing and measuring these changes to aggregate morphology is important to understanding the impact of aggregation on nanoparticle reactive properties. Examples of decreased reactivity due to aggregation include the case where tightly packed aggregates have fewer available surface sites compared to loosely packed ones; also, photocatalytic particles embedded in the center of large aggregates will experience less light when compared to particles embedded in small aggregates. However, aggregation also results in an increase in solid-solid interfaces between nanoparticles. This can result in increased energy transfer between neighboring particles, surface passivation, and altered surface tension. These phenomena can lead to an increase in reactivity. The goal of this thesis is to examine the impacts of aggregation on the reactivity of a select group of nanomaterials. Additionally, we examined how aggregation impacts the removal efficiency of fullerene nanoparticles using membrane filtration. The materials we selected to study include ZnS---a metal chalcogenide

  2. Remote repair appliance

    DOEpatents

    Heumann, Frederick K.; Wilkinson, Jay C.; Wooding, David R.

    1997-01-01

    A remote appliance for supporting a tool for performing work at a worksite on a substantially circular bore of a workpiece and for providing video signals of the worksite to a remote monitor comprising: a baseplate having an inner face and an outer face; a plurality of rollers, wherein each roller is rotatably and adjustably attached to the inner face of the baseplate and positioned to roll against the bore of the workpiece when the baseplate is positioned against the mouth of the bore such that the appliance may be rotated about the bore in a plane substantially parallel to the baseplate; a tool holding means for supporting the tool, the tool holding means being adjustably attached to the outer face of the baseplate such that the working end of the tool is positioned on the inner face side of the baseplate; a camera for providing video signals of the worksite to the remote monitor; and a camera holding means for supporting the camera on the inner face side of the baseplate, the camera holding means being adjustably attached to the outer face of the baseplate. In a preferred embodiment, roller guards are provided to protect the rollers from debris and a bore guard is provided to protect the bore from wear by the rollers and damage from debris.

  3. Remote repair appliance

    DOEpatents

    Heumann, F.K.; Wilkinson, J.C.; Wooding, D.R.

    1997-12-16

    A remote appliance for supporting a tool for performing work at a work site on a substantially circular bore of a work piece and for providing video signals of the work site to a remote monitor comprises: a base plate having an inner face and an outer face; a plurality of rollers, wherein each roller is rotatably and adjustably attached to the inner face of the base plate and positioned to roll against the bore of the work piece when the base plate is positioned against the mouth of the bore such that the appliance may be rotated about the bore in a plane substantially parallel to the base plate; a tool holding means for supporting the tool, the tool holding means being adjustably attached to the outer face of the base plate such that the working end of the tool is positioned on the inner face side of the base plate; a camera for providing video signals of the work site to the remote monitor; and a camera holding means for supporting the camera on the inner face side of the base plate, the camera holding means being adjustably attached to the outer face of the base plate. In a preferred embodiment, roller guards are provided to protect the rollers from debris and a bore guard is provided to protect the bore from wear by the rollers and damage from debris. 5 figs.

  4. The THOSE remote interface

    NASA Astrophysics Data System (ADS)

    Klawon, Kevin; Gold, Josh; Bachman, Kristen

    2013-05-01

    The DIA, in conjunction with the Army Research Lab (ARL), wants to create an Unmanned Ground Sensor (UGS) controller that is (a) interoperable across all controller platforms, (b) capable of easily adding new sensors, radios, and processes and (c) backward compatible with existing UGS systems. To achieve this, a Terra Harvest controller was created that used Java JRE 1.6 and an Open Services Gateway initiative (OSGi) platform, named Terra Harvest Open Software Environment (THOSE). OSGi is an extensible framework that provides a modularized environment for deploying functionality in "bundles". These bundles can publish, discover, and share services available from other external bundles or bundles provided by the controller core. With the addition of a web GUI used for interacting with THOSE, a natural step was then to create a common remote interface that allows 3rd party real-time interaction with the controller. This paper provides an overview of the THOSE system and its components as well as a description of the architectural structure of the remote interface, highlighting the interactions occurring between the controller and the remote interface and its role in providing a positive user experience for managing UGSS functions.

  5. Remote repair appliance

    SciTech Connect

    Heumann, F.K.; Wilkinson, J.C.; Wooding, D.R.

    1996-12-31

    A remote appliance is described for supporting a tool for performing work at a worksite on a substantially circular bore of a workpiece and for providing video signals of the worksite to a remote monitor comprising: a baseplate having an inner face and an outer face; a plurality of rollers, wherein each roller is rotatably and adjustably attached to the inner face of the baseplate and positioned to roll against the bore of the workpiece when the baseplate is positioned against the mouth of the bore such that the appliance may be rotated about the bore in a plane substantially parallel to the baseplate; a tool holding means for supporting the tool, the tool holding means being adjustably attached to the outer face of the baseplate such that the working end of the tool is positioned on the inner face side of the baseplate; a camera for providing video signals of the worksite to the remote monitor; and a camera holding means for supporting the camera on the inner face side of the baseplate, the camera holding means being adjustably attached to the outer face of the baseplate. In a preferred embodiment, roller guards are provided to protect the rollers from debris and a bore guard is provided to protect the bore from wear by the rollers and damage from debris.

  6. Advanced laser remote sensing

    SciTech Connect

    Schultz, J.; Czuchlewski, S.; Karl, R.

    1996-11-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory. Remote measurement of wind velocities is critical to a wide variety of applications such as environmental studies, weather prediction, aircraft safety, the accuracy of projectiles, bombs, parachute drops, prediction of the dispersal of chemical and biological warfare agents, and the debris from nuclear explosions. Major programs to develop remote sensors for these applications currently exist in the DoD and NASA. At present, however, there are no real-time, three-dimensional wind measurement techniques that are practical for many of these applications and we report on two new promising techniques. The first new technique uses an elastic backscatter lidar to track aerosol patterns in the atmosphere and to calculate three dimensional wind velocities from changes in the positions of the aerosol patterns. This was first done by Professor Ed Eloranta of the University of Wisconsin using post processing techniques and we are adapting Professor Eloranta`s algorithms to a real-time data processor and installing it in an existing elastic backscatter lidar system at Los Alamos (the XM94 helicopter lidar), which has a compatible data processing and control system. The second novel wind sensing technique is based on radio-frequency (RF) modulation and spatial filtering of elastic backscatter lidars. Because of their compactness and reliability, solid state lasers are the lasers of choice for many remote sensing applications, including wind sensing.

  7. Memory and betweenness preference in temporal networks induced from time series

    NASA Astrophysics Data System (ADS)

    Weng, Tongfeng; Zhang, Jie; Small, Michael; Zheng, Rui; Hui, Pan

    2017-02-01

    We construct temporal networks from time series via unfolding the temporal information into an additional topological dimension of the networks. Thus, we are able to introduce memory entropy analysis to unravel the memory effect within the considered signal. We find distinct patterns in the entropy growth rate of the aggregate network at different memory scales for time series with different dynamics ranging from white noise, 1/f noise, autoregressive process, periodic to chaotic dynamics. Interestingly, for a chaotic time series, an exponential scaling emerges in the memory entropy analysis. We demonstrate that the memory exponent can successfully characterize bifurcation phenomenon, and differentiate the human cardiac system in healthy and pathological states. Moreover, we show that the betweenness preference analysis of these temporal networks can further characterize dynamical systems and separate distinct electrocardiogram recordings. Our work explores the memory effect and betweenness preference in temporal networks constructed from time series data, providing a new perspective to understand the underlying dynamical systems.

  8. Memory and betweenness preference in temporal networks induced from time series.

    PubMed

    Weng, Tongfeng; Zhang, Jie; Small, Michael; Zheng, Rui; Hui, Pan

    2017-02-03

    We construct temporal networks from time series via unfolding the temporal information into an additional topological dimension of the networks. Thus, we are able to introduce memory entropy analysis to unravel the memory effect within the considered signal. We find distinct patterns in the entropy growth rate of the aggregate network at different memory scales for time series with different dynamics ranging from white noise, 1/f noise, autoregressive process, periodic to chaotic dynamics. Interestingly, for a chaotic time series, an exponential scaling emerges in the memory entropy analysis. We demonstrate that the memory exponent can successfully characterize bifurcation phenomenon, and differentiate the human cardiac system in healthy and pathological states. Moreover, we show that the betweenness preference analysis of these temporal networks can further characterize dynamical systems and separate distinct electrocardiogram recordings. Our work explores the memory effect and betweenness preference in temporal networks constructed from time series data, providing a new perspective to understand the underlying dynamical systems.

  9. Memory and betweenness preference in temporal networks induced from time series

    PubMed Central

    Weng, Tongfeng; Zhang, Jie; Small, Michael; Zheng, Rui; Hui, Pan

    2017-01-01

    We construct temporal networks from time series via unfolding the temporal information into an additional topological dimension of the networks. Thus, we are able to introduce memory entropy analysis to unravel the memory effect within the considered signal. We find distinct patterns in the entropy growth rate of the aggregate network at different memory scales for time series with different dynamics ranging from white noise, 1/f noise, autoregressive process, periodic to chaotic dynamics. Interestingly, for a chaotic time series, an exponential scaling emerges in the memory entropy analysis. We demonstrate that the memory exponent can successfully characterize bifurcation phenomenon, and differentiate the human cardiac system in healthy and pathological states. Moreover, we show that the betweenness preference analysis of these temporal networks can further characterize dynamical systems and separate distinct electrocardiogram recordings. Our work explores the memory effect and betweenness preference in temporal networks constructed from time series data, providing a new perspective to understand the underlying dynamical systems. PMID:28157194

  10. Acceleration of individual, decimetre-sized aggregates in the lower coma of comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Agarwal, Jessica; A'Hearn, M. F.; Vincent, J.-B.; Güttler, C.; Höfner, S.; Sierks, H.; Tubiana, C.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; Barucci, M. A.; Bertaux, J.-L.; Bertini, I.; Boudreault, S.; Cremonese, G.; Da Deppo, V.; Davidsson, B.; Debei, S.; De Cecco, M.; Deller, J.; Fornasier, S.; Fulle, M.; Gicquel, A.; Groussin, O.; Gutiérrez, P. J.; Hofmann, M.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Keller, H. U.; Knollenberg, J.; Kramm, J.-R.; Kührt, E.; Küppers, M.; Lara, L. M.; Lazzarin, M.; Lopez Moreno, J. J.; Marzari, F.; Naletto, G.; Oklay, N.; Shi, X.; Thomas, N.

    2016-11-01

    We present observations of decimetre-sized, likely ice-containing aggregates ejected from a confined region on the surface of comet 67P/Churyumov-Gerasimenko. The images were obtained with the narrow angle camera of the Optical, Spectroscopic, and Infrared Remote Imaging System on board the Rosetta spacecraft in 2016 January when the comet was at 2 au from the Sun outbound from perihelion. We measure the acceleration of individual aggregates through a 2 h image series. Approximately 50 per cent of the aggregates are accelerated away from the nucleus, and 50 per cent towards it, and likewise towards either horizontal direction. The accelerations are up to one order of magnitude stronger than local gravity, and are most simply explained by the combined effect of gas drag accelerating all aggregates upwards, and the recoil force from asymmetric outgassing, either from rotating aggregates with randomly oriented spin axes and sufficient thermal inertia to shift the temperature maximum away from an aggregate's subsolar region, or from aggregates with variable ice content. At least 10 per cent of the aggregates will escape the gravity field of the nucleus and feed the comet's debris trail, while others may fall back to the surface and contribute to the deposits covering parts of the Northern hemisphere. The rocket force plays a crucial role in pushing these aggregates back towards the surface. Our observations show the future back fall material in the process of ejection, and provide the first direct measurement of the acceleration of aggregates in the innermost coma (<2 km) of a comet, where gas drag is still significant.

  11. Long memory in patterns of mobile phone usage

    NASA Astrophysics Data System (ADS)

    Owczarczuk, Marcin

    2012-02-01

    In this article we show that usage of a mobile phone, i.e. daily series of number of calls made by a customer, exhibits long memory. We use a sample of 4502 postpaid users from a Polish mobile operator and study their two-year billing history. We estimate Hurst exponent by nine estimators: aggregated variance method, differencing the variance, absolute values of the aggregated series, Higuchi's method, residuals of regression, the R/S method, periodogram method, modified periodogram method and Whittle estimator. We also analyze empirically relations between estimators. Long memory implies an inertial effect in clients' behavior which may be used by mobile operators to accelerate usage and gain additional profit.

  12. 7 CFR 1.6 - Aggregating requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Aggregating requests. 1.6 Section 1.6 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Official Records § 1.6 Aggregating requests. When an agency reasonably believes that a requester, or a group of requesters acting in...

  13. 7 CFR 1.6 - Aggregating requests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Aggregating requests. 1.6 Section 1.6 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Official Records § 1.6 Aggregating requests. When an agency reasonably believes that a requester, or a group of requesters acting in...

  14. Biomass round bales infield aggregation logistic scenarios

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biomass bales often need to be aggregated (collected into groups and transported) to a field-edge stack for temporary storage for feedlots or processing facilities. Aggregating the bales with the least total distance involved is a goal of producers and bale handlers. Several logistics scenarios for ...

  15. The Aggregate Demand Curve: A Reply.

    ERIC Educational Resources Information Center

    Hansen, Richard B.; And Others

    1987-01-01

    Responds to claims about the instructional value of the downward-sloping aggregate demand curve in teaching principles of macroeconomics. Examines the effects of interest-rates and the role of money on demand curves. Concludes by arguing against the use of downward-sloping aggregate demand curves in textbooks. (RKM)

  16. 42 CFR 411.106 - Aggregation rules.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false Aggregation rules. 411.106 Section 411.106 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM... Under Group Health Plans: General Provisions § 411.106 Aggregation rules. The following rules apply...

  17. 42 CFR 411.106 - Aggregation rules.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Aggregation rules. 411.106 Section 411.106 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM... Under Group Health Plans: General Provisions § 411.106 Aggregation rules. The following rules apply...

  18. Choosing Aggregation Rules for Composite Indicators

    ERIC Educational Resources Information Center

    Munda, Giuseppe

    2012-01-01

    From a formal point of view, a composite indicator is an aggregate of all dimensions, objectives, individual indicators and variables used for its construction. This implies that what defines a composite indicator is the set of properties underlying its mathematical aggregation convention. In this article, I try to revise the theoretical debate on…

  19. Molecular dynamics simulation of fractal aggregate diffusion

    NASA Astrophysics Data System (ADS)

    Pranami, Gaurav; Lamm, Monica H.; Vigil, R. Dennis

    2010-11-01

    The diffusion of fractal aggregates constructed with the method by Thouy and Jullien [J. Phys. A 27, 2953 (1994)10.1088/0305-4470/27/9/012] comprised of Np spherical primary particles was studied as a function of the aggregate mass and fractal dimension using molecular dynamics simulations. It is shown that finite-size effects have a strong impact on the apparent value of the diffusion coefficient (D) , but these can be corrected by carrying out simulations using different simulation box sizes. Specifically, the diffusion coefficient is inversely proportional to the length of a cubic simulation box, and the constant of proportionality appears to be independent of the aggregate mass and fractal dimension. Using this result, it is possible to compute infinite dilution diffusion coefficients (Do) for aggregates of arbitrary size and fractal dimension, and it was found that Do∝Np-1/df , as is often assumed by investigators simulating Brownian aggregation of fractal aggregates. The ratio of hydrodynamic radius to radius of gyration is computed and shown to be independent of mass for aggregates of fixed fractal dimension, thus enabling an estimate of the diffusion coefficient for a fractal aggregate based on its radius of gyration.

  20. Oxygen limitation within a bacterial aggregate.

    PubMed

    Wessel, Aimee K; Arshad, Talha A; Fitzpatrick, Mignon; Connell, Jodi L; Bonnecaze, Roger T; Shear, Jason B; Whiteley, Marvin

    2014-04-15

    ABSTRACT Cells within biofilms exhibit physiological heterogeneity, in part because of chemical gradients existing within these spatially structured communities. Previous work has examined how chemical gradients develop in large biofilms containing >10(8) cells. However, many bacterial communities in nature are composed of small, densely packed aggregates of cells (≤ 10(5) bacteria). Using a gelatin-based three-dimensional (3D) printing strategy, we confined the bacterium Pseudomonas aeruginosa within picoliter-sized 3D "microtraps" that are permeable to nutrients, waste products, and other bioactive small molecules. We show that as a single bacterium grows into a maximally dense (10(12) cells ml(-1)) clonal population, a localized depletion of oxygen develops when it reaches a critical aggregate size of ~55 pl. Collectively, these data demonstrate that chemical and phenotypic heterogeneity exists on the micrometer scale within small aggregate populations. IMPORTANCE Before developing into large, complex communities, microbes initially cluster into aggregates, and it is unclear if chemical heterogeneity exists in these ubiquitous micrometer-scale aggregates. We chose to examine oxygen availability within an aggregate since oxygen concentration impacts a number of important bacterial processes, including metabolism, social behaviors, virulence, and antibiotic resistance. By determining that oxygen availability can vary within aggregates containing ≤ 10(5) bacteria, we establish that physiological heterogeneity exists within P. aeruginosa aggregates, suggesting that such heterogeneity frequently exists in many naturally occurring small populations.

  1. Teaching Aggregate Demand and Supply Models

    ERIC Educational Resources Information Center

    Wells, Graeme

    2010-01-01

    The author analyzes the inflation-targeting model that underlies recent textbook expositions of the aggregate demand-aggregate supply approach used in introductory courses in macroeconomics. He shows how numerical simulations of a model with inflation inertia can be used as a tool to help students understand adjustments in response to demand and…

  2. Human learning and memory.

    PubMed

    Johnson, M K; Hasher, L

    1987-01-01

    There have been several notable recent trends in the area of learning and memory. Problems with the episodic/semantic distinction have become more apparent, and new efforts have been made (exemplar models, distributed-memory models) to represent general knowledge without assuming a separate semantic system. Less emphasis is being placed on stable, prestored prototypes and more emphasis on a flexible memory system that provides the basis for a multitude of categories or frames of reference, derived on the spot as tasks demand. There is increasing acceptance of the idea that mental models are constructed and stored in memory in addition to, rather than instead of, memorial representations that are more closely tied to perceptions. This gives rise to questions concerning the conditions that permit inferences to be drawn and mental models to be constructed, and to questions concerning the similarities and differences in the nature of the representations in memory of perceived and generated information and in their functions. There has also been a swing from interest in deliberate strategies to interest in automatic, unconscious (even mechanistic!) processes, reflecting an appreciation that certain situations (e.g. recognition, frequency judgements, savings in indirect tasks, aspects of skill acquisition, etc) seem not to depend much on the products of strategic, effortful or reflective processes. There is a lively interest in relations among memory measures and attempts to characterize memory representations and/or processes that could give rise to dissociations among measures. Whether the pattern of results reflects the operation of functional subsystems of memory and, if so, what the "modules" are is far from clear. This issue has been fueled by work with amnesics and has contributed to a revival of interaction between researchers studying learning and memory in humans and those studying learning and memory in animals. Thus, neuroscience rivals computer science as a

  3. System and method for controlling remote devices

    DOEpatents

    Carrender, Curtis Lee; Gilbert, Ronald W.; Scott, Jeff W.; Clark, David A.

    2006-02-07

    A system and method for controlling remote devices utilizing a radio frequency identification (RFID) tag device having a control circuit adapted to render the tag device, and associated objects, permanently inoperable in response to radio-frequency control signals. The control circuit is configured to receive the control signals that can include an enable signal, and in response thereto enable an associated object, such as a weapon; and in response to a disable signal, to disable the tag itself, or, if desired, to disable the associated weapon or both the device and the weapon. Permanent disabling of the tag can be accomplished by several methods, including, but not limited to, fusing a fusable link, breaking an electrically conductive path, permanently altering the modulation or backscattering characteristics of the antenna circuit, and permanently erasing an associated memory. In this manner, tags in the possession of unauthorized employees can be remotely disabled, and weapons lost on a battlefield can be easily tracked and enabled or disabled automatically or at will.

  4. Aggregate size distribution of the soil loss

    NASA Astrophysics Data System (ADS)

    Szabó, Judit Alexandra; Jakab, Gergely; Szabó, Boglárka; Józsa, Sándor; Szalai, Zoltán; Centeri, Csaba

    2016-04-01

    In agricultural areas the soil erosion and soil loss estimation is vital information in long-term planning. During the initial period of the erosion a part of the soil particles and aggregates get transportable and nutrients and organic matter could be transported due to the effect of water or wind. This preliminary phase was studied with laboratory-scale rainfall simulator. Developed surface crust and aggregate size composition of the runoff was examined in six different slope-roughness-moisture content combination of a Cambisol and a Regosol. The ratio of micro- and macro aggregates in the runoff indicate the stability of the aggregates and determine the transport capacity of the runoff. Both soil samples were taken from field where the water erosion is a potential hazard. During the experiment the whole amount of runoff and sediment was collected through sieve series to a bucket to separate the micro- and macro aggregates. In case of both samples the micro aggregates dominate in the runoff and the runoff rates are similar. Although the runoff of the Regosol - with dominant >1000μm macro aggregate content - contained almost nothing but <50μm sized micro aggregates. Meanwhile the runoff of the Cambisol - with more balanced micro and macro aggregate content - contained dominantly 50-250μm sized micro aggregates and in some case remarkable ratio 250-1000μm sized macro aggregates. This difference occurred because the samples are resistant against drop erosion differently. In case of both sample the selectivity of the erosion and substance matrix redistribution manifested in mineral crusts in the surface where the quartz deposited in place while the lighter organic matter transported with the sediment. The detachment of the aggregates and the redistribution of the particles highly effect on the aggregate composition of the runoff which is connected with the quality of the soil loss. So while the estimation of soil loss quantity is more or less is easy, measuring

  5. Conscious and Unconscious Memory Systems

    PubMed Central

    Squire, Larry R.; Dede, Adam J.O.

    2015-01-01

    The idea that memory is not a single mental faculty has a long and interesting history but became a topic of experimental and biologic inquiry only in the mid-20th century. It is now clear that there are different kinds of memory, which are supported by different brain systems. One major distinction can be drawn between working memory and long-term memory. Long-term memory can be separated into declarative (explicit) memory and a collection of nondeclarative (implicit) forms of memory that include habits, skills, priming, and simple forms of conditioning. These memory systems depend variously on the hippocampus and related structures in the parahippocampal gyrus, as well as on the amygdala, the striatum, cerebellum, and the neocortex. This work recounts the discovery of declarative and nondeclarative memory and then describes the nature of declarative memory, working memory, nondeclarative memory, and the relationship between memory systems. PMID:25731765

  6. Ovine colostrum nanopeptide affects amyloid beta aggregation.

    PubMed

    Janusz, Maria; Woszczyna, Mirosław; Lisowski, Marek; Kubis, Adriana; Macała, Józefa; Gotszalk, Teodor; Lisowski, Józef

    2009-01-05

    A colostral proline-rich polypeptide complex (PRP) consisting of over 30 peptides shows beneficial effects in Alzheimer's disease (AD) patients when administered in the form of sublinqual tablets called Colostrinin. The aim of the present studies was to investigate whether nanopeptide fragment of PRP (NP) - one of the PRP complex components can affect aggregation of amyloid beta (Abeta1-42). The effect of NP on Abeta aggregation was studied using Thioflavin T (ThT) binding, atomic force microscopy, and analyzing circular dichroism spectra. Results presented suggest that NP can directly interact with amyloid beta, inhibit its aggregation and disrupt existing aggregates acting as a beta sheet breaker and reduce toxicity induced by aggregated forms of Abeta.

  7. Aggregation of sodium alkylbenzenesulfonates in aqueous solution

    SciTech Connect

    Magid, L.J.; Shaver, R.J.; Gulari, E.; Bedwell, B.; Alkhafaji, S.

    1981-01-01

    The surfactant 6 phenyl C/sub 12/SNa forms small spherical micelles in aqueous solution, having an aggregation number of 20 to 30 and a fractional charge of 0.45. These micelles are hydrated to the extent of approximately 18 moles H/sub 2/O per moles of surfactant. A second larger aggregate is also present in 6 phenyl C/sub 12/SNa solutions; its importance increases with solution age. Addition of NaCl causes both aggregates to apparently increase modestly in size. The surfactant 8 phenyl C/sub 16/SNa also contains both aggregates in its solutions; the larger one is relatively more important here. The larger aggregate does not correspond to dispersed bits of a liquid crystalline mesophase.

  8. Multicandidate Elections: Aggregate Uncertainty in the Laboratory*

    PubMed Central

    Bouton, Laurent; Castanheira, Micael; Llorente-Saguer, Aniol

    2015-01-01

    The rational-voter model is often criticized on the grounds that two of its central predictions (the paradox of voting and Duverger’s Law) are at odds with reality. Recent theoretical advances suggest that these empirically unsound predictions might be an artifact of an (arguably unrealistic) assumption: the absence of aggregate uncertainty about the distribution of preferences in the electorate. In this paper, we propose direct empirical evidence of the effect of aggregate uncertainty in multicandidate elections. Adopting a theory-based experimental approach, we explore whether aggregate uncertainty indeed favors the emergence of non-Duverger’s law equilibria in plurality elections. Our experimental results support the main theoretical predictions: sincere voting is a predominant strategy under aggregate uncertainty, whereas without aggregate uncertainty, voters massively coordinate their votes behind one candidate, who wins almost surely. PMID:28298811

  9. Blood platelet aggregation and personality traits.

    PubMed

    Jenkins, C D; Thomas, G; Olewine, D; Zyzanski, S J; Simpson, M T; Hames, C G

    1975-12-01

    Changes in blood platelet aggregation may precipitate episodes of arterial occlusive diseases. Little is known, however, regarding the influence of psychological traits, emotional states and other behavioral stressors on platelet aggregation phenomena. This study examined 46 healthy college men at rest and after submaximal treadmill exercise. Associations were found between the duration of platelet aggregation and a number of scores from the California Psychological Inventory and self-administered anxiety scales. The more socially adequate, poised and dominant persons--those with more mature ego development and less overt anxiety--had platelets with more prolonged aggregation reactions to the in vitro introduction of noradrenalin. Irreversible aggregation of platelets occurred more regularly to lower in vitro concentrations of noradrenalin in platelet samples drawn from subjects who were less anxious and tended to be more rigidly defensive. It is premature to attempt to derive clinical implications from this exploratory work, but some implications for the design of future research are discussed.

  10. Dissociating memory traces and scenario construction in mental time travel.

    PubMed

    Cheng, Sen; Werning, Markus; Suddendorf, Thomas

    2016-01-01

    There has been a persistent debate about how to define episodic memory and whether it is a uniquely human capacity. On the one hand, many animal cognition studies employ content-based criteria, such as the what-where-when criterion, and argue that nonhuman animals possess episodic memory. On the other hand, many human cognition studies emphasize the subjective experience during retrieval as an essential property of episodic memory and the distinctly human foresight it purportedly enables. We propose that both perspectives may examine distinct but complementary aspects of episodic memory by drawing a conceptual distinction between episodic memory traces and mental time travel. Episodic memory traces are sequential mnemonic representations of particular, personally experienced episodes. Mental time travel draws on these traces, but requires other components to construct scenarios and embed them into larger narratives. Various nonhuman animals may store episodic memory traces, and yet it is possible that only humans are able to construct and reflect on narratives of their lives - and flexibly compare alternative scenarios of the remote future.

  11. A generalized memory test algorithm

    NASA Technical Reports Server (NTRS)

    Milner, E. J.

    1982-01-01

    A general algorithm for testing digital computer memory is presented. The test checks that (1) every bit can be cleared and set in each memory work, and (2) bits are not erroneously cleared and/or set elsewhere in memory at the same time. The algorithm can be applied to any size memory block and any size memory word. It is concise and efficient, requiring the very few cycles through memory. For example, a test of 16-bit-word-size memory requries only 384 cycles through memory. Approximately 15 seconds were required to test a 32K block of such memory, using a microcomputer having a cycle time of 133 nanoseconds.

  12. Regulatory T cell memory

    PubMed Central

    Rosenblum, Michael D.; Way, Sing Sing; Abbas, Abul K.

    2016-01-01

    Memory for antigen is a defining feature of adaptive immunity. Antigen-specific lymphocyte populations show an increase in number and function after antigen encounter and more rapidly re-expand upon subsequent antigen exposure. Studies of immune memory have primarily focused on effector B cells and T cells with microbial specificity, using prime challenge models of infection. However, recent work has also identified persistently expanded populations of antigen-specific regulatory T cells that protect against aberrant immune responses. In this Review, we consider the parallels between memory effector T cells and memory regulatory T cells, along with the functional implications of regulatory memory in autoimmunity, antimicrobial host defence and maternal fetal tolerance. In addition, we discuss emerging evidence for regulatory T cell memory in humans and key unanswered questions in this rapidly evolving field. PMID:26688349

  13. Shape memory polymers

    DOEpatents

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  14. Classification and Characterization of Therapeutic Antibody Aggregates

    PubMed Central

    Joubert, Marisa K.; Luo, Quanzhou; Nashed-Samuel, Yasser; Wypych, Jette; Narhi, Linda O.

    2011-01-01

    A host of diverse stress techniques was applied to a monoclonal antibody (IgG2) to yield protein particles with varying attributes and morphologies. Aggregated solutions were evaluated for percent aggregation, particle counts, size distribution, morphology, changes in secondary and tertiary structure, surface hydrophobicity, metal content, and reversibility. Chemical modifications were also identified in a separate report (Luo, Q., Joubert, M. K., Stevenson, R., Narhi, L. O., and Wypych, J. (2011) J. Biol. Chem. 286, 25134–25144). Aggregates were categorized into seven discrete classes, based on the traits described. Several additional molecules (from the IgG1 and IgG2 subtypes as well as intravenous IgG) were stressed and found to be defined with the same classification system. The mechanism of protein aggregation and the type of aggregate formed depends on the nature of the stress applied. Different IgG molecules appear to aggregate by a similar mechanism under the same applied stress. Aggregates created by harsh mechanical stress showed the largest number of subvisible particles, and the class generated by thermal stress displayed the largest number of visible particles. Most classes showed a disruption of the higher order structure, with the degree of disorder depending on the stress process. Particles in all classes (except thermal stress) were at least partially reversible upon dilution in pH 5 buffer. High copper content was detected in isolated metal-catalyzed aggregates, a stress previously shown to produce immunogenic aggregates. In conclusion, protein aggregates can be a very heterogeneous population, whose qualities are the result of the type of stress that was experienced. PMID:21454532

  15. Content Addressable Memory Project

    DTIC Science & Technology

    1990-11-01

    The Content Addressable M1-emory Project consists of the development of several experimental software systems on an AMT Distributed Array Processor...searching (database) compiler algorithms memory management other systems software) Linear C is an unlovely hybrid language which imports the CAM...memory from AMT’s operating system for the DAP; how- ever, other than this limitation, the memory management routines work exactly as their C counterparts

  16. Sparse distributed memory

    NASA Technical Reports Server (NTRS)

    Kanerva, Pentti

    1988-01-01

    Theoretical models of the human brain and proposed neural-network computers are developed analytically. Chapters are devoted to the mathematical foundations, background material from computer science, the theory of idealized neurons, neurons as address decoders, and the search of memory for the best match. Consideration is given to sparse memory, distributed storage, the storage and retrieval of sequences, the construction of distributed memory, and the organization of an autonomous learning system.

  17. Memory Load and Dump

    NASA Astrophysics Data System (ADS)

    Welty, Alan

    2009-07-01

    This proposal is a test and verification of the STIS dump of memory capability.Areas of Control Section {CS} to dump include: EDAC RAM, EEPROM, and CS PROM {with the CS in Operate}. Areas of MIE memory to dump include: MIE RAM and MIE PROM {with the MIE in Operate}. Note that the MIE memory must first be copied to CS buffer RAM as images, which are then dumped.Supports Activity STIS-02

  18. Myrmics Memory Allocator

    SciTech Connect

    Lymperis, S.

    2011-09-23

    MMA is a stand-alone memory management system for MPI clusters. It implements a shared Partitioned Global Address Space, where multiple MPI processes request objects from the allocator and the latter provides them with system-wide unique memory addresses for each object. It provides applications with an intuitive way of managing the memory system in a unified way, thus enabling easier writing of irregular application code.

  19. Memory Golf Clubs

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Memory Corporation's investigation of shape memory effect, stemming from Marshall Space Flight Center contracts to study materials for the space station, has aided in the development of Zeemet, a proprietary, high-damping shape memory alloy for the golf industry. The Nicklaus Golf Company has created a new line of golf clubs using Zeemet inserts. Its superelastic and high damping attributes translate into more spin on the ball, greater control, and a solid feel.

  20. Experimental investigations on aggregate-aggregate collisions in the early solar nebula

    NASA Astrophysics Data System (ADS)

    Blum, Jürgen; Münch, Michael

    1993-11-01

    An experimental setup has been devised to study the low-velocity aggregate-aggregate collisions that play a role in determining aggregate sizes in the preplanetary nebula; both central and grazing collisions are in this way studied for both ZrSiO4 and Aerosil 200. Fragment-mass distributions for catastrophic collisions between equal-sized aggregates are extrapolated according to several assumptions of the simple fragmentation model chosen. The model predicts a complete disintegration of the ZrSiO4 equal-size aggregates.

  1. Sans study of asphaltene aggregation

    SciTech Connect

    Overfield, R.E.; Sheu, E.Y.; Sinha, S.K.; Liang, K.S. )

    1988-06-01

    The colloidal properties of asphaltenes have long been recognized from peculiarities in their solubility and colligative properties. A layered micellar model or asphaltenes was proposed by others in which a highly condensed alkyl aromatic formed the central part, and molecules of decreasingly aromatic character (resins) clustered around them. Numerous studies, based on a variety of techniques such as ultracentrifugation and electron microscopy indicated a particulate nature for asphaltenes with size 20-40 A diameter. Others have proposed a refined model based on x-ray diffraction and small angle scattering. In this model, interactions between flat sheets of condensed aromatic rings form the central ''crystallite'' part of a spherical particle with the outer part being comprised of the aliphatic positions of the same molecules. These particles are bunched together with some degree of entanglement into ''micelles''. Concentration and solvent dependent radii of gyration, ranging from 30-50 A were reported. The aggregation creates a good deal of uncertainty as to the true molecular size or weight of asphaltenes. Neutron scattering offers novel contrast relative to light scattering (refractive index) and x-ray scattering (electron density). This is because the scattering length of proton is negative, whereas that from deuterium and other nuclei such as C, S, O, and N are positive. Thus by replacing hydrogen with deuterium in either the solvent or the scatterer the contrast can be varied, and different parts of the molecule can be highlighted.

  2. Aggregate Models of Climate Change

    NASA Astrophysics Data System (ADS)

    Hooss, G.; Voss, R.; Hasselmann, K.; Maier-Reimer, E.; Joos, F.

    Integrated assessment of climate change generally requires the evaluation of many transient scenario simulations of century-timescale changes in atmospheric compo- sition and climate, desirably with the accuracy of state-of-the-art three-dimensional (3D) coupled atmosphere-ocean general circulation models (GCMs). Such multi- scenario GCM computations are possible through appropriate representation of the models in aggregate forms. For this purpose, we developed Nonlinear Impulse- response projections of 3D models of the global (oceanic and terrestrial) Carbon cycle and the atmosphere-ocean Climate System (NICCS). For higher CO2 forcing, appli- cability is extended beyond the linear response domain through explicit treatment of dominant nonlinear effects. The climate change module was furthermore augmented with spatial patterns of change in some of the most impact-relevant fields. Applied to three long-term CO2 emission scenarios, the model demonstrates (a) the minor rela- tive role of the terrestrial carbon sink through CO2 fertilization, and (b) the necessity to reduce fossil carbon emissions to a very small fraction of today's rates within the next few decades if a major climate change is to be avoided.

  3. The fractal aggregation of asphaltenes.

    PubMed

    Hoepfner, Michael P; Fávero, Cláudio Vilas Bôas; Haji-Akbari, Nasim; Fogler, H Scott

    2013-07-16

    This paper discusses time-resolved small-angle neutron scattering results that were used to investigate asphaltene structure and stability with and without a precipitant added in both crude oil and model oil. A novel approach was used to isolate the scattering from asphaltenes that are insoluble and in the process of aggregating from those that are soluble. It was found that both soluble and insoluble asphaltenes form fractal clusters in crude oil and the fractal dimension of the insoluble asphaltene clusters is higher than that of the soluble clusters. Adding heptane also increases the size of soluble asphaltene clusters without modifying the fractal dimension. Understanding the process of insoluble asphaltenes forming fractals with higher fractal dimensions will potentially reveal the microscopic asphaltene destabilization mechanism (i.e., how a precipitant modifies asphaltene-asphaltene interactions). It was concluded that because of the polydisperse nature of asphaltenes, no well-defined asphaltene phase stability envelope exists and small amounts of asphaltenes precipitated even at dilute precipitant concentrations. Asphaltenes that are stable in a crude oil-precipitant mixture are dispersed on the nanometer length scale. An asphaltene precipitation mechanism is proposed that is consistent with the experimental findings. Additionally, it was found that the heptane-insoluble asphaltene fraction is the dominant source of small-angle scattering in crude oil and the previously unobtainable asphaltene solubility at low heptane concentrations was measured.

  4. Networks of Memories

    DTIC Science & Technology

    2013-03-01

    2000). The construction of  autobiographical   memories in the self­memory system. Psychological Review, 107(2), 261­288. Dennis, S., & Chapman, A. (2010...AFRL-OSR-VA-TR-2013-0131 Networks of Memories Simon Dennis, Mikhail Belkin Ohio State University March 2013 Final...Back (Rev. 8/98) 1 Networks of  Memories FA9550­09­1­0614 Professor Jay Myung PI: Simon Dennis Ohio State University February 15, 2013 2 Introduction

  5. Hypnosis, memory and amnesia.

    PubMed Central

    Kihlstrom, J F

    1997-01-01

    Hypnotized subjects respond to suggestions from the hypnotist for imaginative experiences involving alterations in perception and memory. Individual differences in hypnotizability are only weakly related to other forms of suggestibility. Neuropsychological speculations about hypnosis focus on the right hemisphere and/or the frontal lobes. Posthypnotic amnesia refers to subjects' difficulty in remembering, after hypnosis, the events and experiences that transpired while they were hypnotized. Posthypnotic amnesia is not an instance of state-dependent memory, but it does seem to involve a disruption of retrieval processes similar to the functional amnesias observed in clinical dissociative disorders. Implicit memory, however, is largely spared, and may underlie subjects' ability to recognize events that they cannot recall. Hypnotic hypermnesia refers to improved memory for past events. However, such improvements are illusory: hypermnesia suggestions increase false recollection, as well as subjects' confidence in both true and false memories. Hypnotic age regression can be subjectively compelling, but does not involve the ablation of adult memory, or the reinstatement of childlike modes of mental functioning, or the revivification of memory. The clinical and forensic use of hypermnesia and age regression to enhance memory in patients, victims and witnesses (e.g. recovered memory therapy for child sexual abuse) should be discouraged. PMID:9415925

  6. New gravitational memories

    NASA Astrophysics Data System (ADS)

    Pasterski, Sabrina; Strominger, Andrew; Zhiboedov, Alexander

    2016-12-01

    The conventional gravitational memory effect is a relative displacement in the position of two detectors induced by radiative energy flux. We find a new type of gravitational `spin memory' in which beams on clockwise and counterclockwise orbits acquire a relative delay induced by radiative angular momentum flux. It has recently been shown that the displacement memory formula is a Fourier transform in time of Weinberg's soft graviton theorem. Here we see that the spin memory formula is a Fourier transform in time of the recently-discovered subleading soft graviton theorem.

  7. Sparse distributed memory overview

    NASA Technical Reports Server (NTRS)

    Raugh, Mike

    1990-01-01

    The Sparse Distributed Memory (SDM) project is investigating the theory and applications of massively parallel computing architecture, called sparse distributed memory, that will support the storage and retrieval of sensory and motor patterns characteristic of autonomous systems. The immediate objectives of the project are centered in studies of the memory itself and in the use of the memory to solve problems in speech, vision, and robotics. Investigation of methods for encoding sensory data is an important part of the research. Examples of NASA missions that may benefit from this work are Space Station, planetary rovers, and solar exploration. Sparse distributed memory offers promising technology for systems that must learn through experience and be capable of adapting to new circumstances, and for operating any large complex system requiring automatic monitoring and control. Sparse distributed memory is a massively parallel architecture motivated by efforts to understand how the human brain works. Sparse distributed memory is an associative memory, able to retrieve information from cues that only partially match patterns stored in the memory. It is able to store long temporal sequences derived from the behavior of a complex system, such as progressive records of the system's sensory data and correlated records of the system's motor controls.

  8. The future of memory

    NASA Astrophysics Data System (ADS)

    Marinella, M.

    In the not too distant future, the traditional memory and storage hierarchy of may be replaced by a single Storage Class Memory (SCM) device integrated on or near the logic processor. Traditional magnetic hard drives, NAND flash, DRAM, and higher level caches (L2 and up) will be replaced with a single high performance memory device. The Storage Class Memory paradigm will require high speed (< 100 ns read/write), excellent endurance (> 1012), nonvolatility (retention > 10 years), and low switching energies (< 10 pJ per switch). The International Technology Roadmap for Semiconductors (ITRS) has recently evaluated several potential candidates SCM technologies, including Resistive (or Redox) RAM, Spin Torque Transfer RAM (STT-MRAM), and phase change memory (PCM). All of these devices show potential well beyond that of current flash technologies and research efforts are underway to improve the endurance, write speeds, and scalabilities to be on-par with DRAM. This progress has interesting implications for space electronics: each of these emerging device technologies show excellent resistance to the types of radiation typically found in space applications. Commercially developed, high density storage class memory-based systems may include a memory that is physically radiation hard, and suitable for space applications without major shielding efforts. This paper reviews the Storage Class Memory concept, emerging memory devices, and possible applicability to radiation hardened electronics for space.

  9. The Persistence of Hippocampal-Based Memory Requires Protein Synthesis Mediated by the Prion-like Protein CPEB3.

    PubMed

    Fioriti, Luana; Myers, Cory; Huang, Yan-You; Li, Xiang; Stephan, Joseph S; Trifilieff, Pierre; Colnaghi, Luca; Kosmidis, Stylianos; Drisaldi, Bettina; Pavlopoulos, Elias; Kandel, Eric R

    2015-06-17

    Consolidation of long-term memories depends on de novo protein synthesis. Several translational regulators have been identified, and their contribution to the formation of memory has been assessed in the mouse hippocampus. None of them, however, has been implicated in the persistence of memory. Although persistence is a key feature of long-term memory, how this occurs, despite the rapid turnover of its molecular substrates, is poorly understood. Here we find that both memory storage and its underlying synaptic plasticity are mediated by the increase in level and in the aggregation of the prion-like translational regulator CPEB3 (cytoplasmic polyadenylation element-binding protein). Genetic ablation of CPEB3 impairs the maintenance of both hippocampal long-term potentiation and hippocampus-dependent spatial memory. We propose a model whereby persistence of long-term memory results from the assembly of CPEB3 into aggregates. These aggregates serve as functional prions and regulate local protein synthesis necessary for the maintenance of long-term memory.

  10. Variable aggregation rates in colloidal gold: Kernel homogeneity dependence on aggregant concentration

    NASA Astrophysics Data System (ADS)

    Olivier, B. J.; Sorensen, C. M.

    1990-02-01

    Dynamic light scattering is used to study the dependence of the aggregation kernel homogeneity λ on the aggregant concentration [HCl] for aqueous gold sols. We find the cluster growth kinetics are well described by a powerlaw, Rapp~tz/D, where Rapp is the measured apparent radius, D the cluster fractal dimension, and z=1/(1-λ) for all aggregant concentrations. The values for the dynamic exponent z, and hence the homogeneity λ, are functions of HCl concentration. We find the larger HCl concentrations yield a fast-aggregation regime characterized by λ~=-0.6. Smaller HCl concentrations yield a continuum of aggregation regimes characterized by homogeneities evolving from λ~=-0.6 towards 1.0. Our results do not support the view that aggregation in gold colloids is based on two limiting regimes, diffusion-limited and reaction-limited aggregation.

  11. Dispersion of ferrofluid aggregates in steady flows

    NASA Astrophysics Data System (ADS)

    Williams, Alicia M.; Vlachos, Pavlos P.

    2011-12-01

    Using focused shadowgraphs, we investigate steady flows of a magnetically non-susceptible fluid interacting with ferrofluid aggregates comprised of superparamagnetic nanoparticles. The ferrofluid aggregate is retained at a specific site within the flow channel using two different applied magnetic fields. The bulk flow induces shear stresses on the aggregate, which give rise to the development of interfacial disturbances, leading to Kelvin-Helmholtz (K-H) instabilities and shedding of ferrofluid structures. Herein, the effects of bulk Reynolds number, ranging from 100 to 1000, and maximum applied magnetic fields of 1.2 × 105 and 2.4 × 105 A/m are investigated in the context of their impact on dispersion or removal of material from the core aggregate. The aggregate interaction with steady bulk flow reveals three regimes of aggregate dynamics over the span of Reynolds numbers studied: stable, transitional, and shedding. The first regime is characterized by slight aggregate stretching for low Reynolds numbers, with full aggregate retention. As the Reynolds number increases, the aggregate is in-transition between stable and shedding states. This second regime is characterized by significant initial stretching that gives way to small amplitude Kelvin-Helmholtz waves. Higher Reynolds numbers result in ferrofluid shedding, with Strouhal numbers initially between 0.2 and 0.3, wherein large vortical structures are shed from the main aggregate accompanied by precipitous decay of the accumulated ferrofluid aggregate. These behaviors are apparent for both magnetic field strengths, although the transitional Reynolds numbers are different between the cases, as are the characteristic shedding frequencies relative to the same Reynolds number. In the final step of this study, relevant parameters were extracted from the time series dispersion data to comprehensively quantify aggregate mechanics. The aggregate half-life is found to decrease as a function of the Reynolds number

  12. Amyloid-beta aggregation: selective inhibition of aggregation in mixtures of amyloid with different chain lengths.

    PubMed Central

    Snyder, S W; Ladror, U S; Wade, W S; Wang, G T; Barrett, L W; Matayoshi, E D; Huffaker, H J; Krafft, G A; Holzman, T F

    1994-01-01

    One of the clinical manifestations of Alzheimer's disease is the deposition of the 39-43 residue amyloid-beta (A beta) peptide in aggregated fibrils in senile plaques. Characterization of the aggregation behavior of A beta is one of the critical issues in understanding the role of A beta in the disease process. Using solution hydrodynamics, A beta was observed to form three types of species in phosphate-buffered saline: insoluble aggregates with sedimentation coefficients of approximately 50,000 S and molecular masses of approximately 10(9) Da, "soluble aggregates" with sedimentation coefficients of approximately 30 S and masses of approximately 10(6) Da, and monomer. When starting from monomer, the aggregation kinetics of A beta 1-40 (A beta 40) and A beta 1-42 (A beta 42), alone and in combination, reveal large differences in the tendency of these peptides to aggregate as a function of pH and other solution conditions. At pH 4.1 and 7.0-7.4, aggregation is significantly slower than at pH 5 and 6. Under all conditions, aggregation of the longer A beta 42 was more rapid than A beta 40. Oxidation of Met-35 to the sulfoxide in A beta 40 enhances the aggregation rate over that of the nonoxidized peptide. Aggregation was found to be dependent upon temperature and to be strongly dependent on peptide concentration and ionic strength, indicating that aggregation is driven by a hydrophobic effect. When A beta 40 and A beta 42 are mixed together, A beta 40 retards the aggregation of A beta 42 in a concentration-dependent manner. Shorter fragments have a decreasing ability to interfere with A beta 42 aggregation. Conversely, the rate of aggregation of A beta 40 can be significantly enhanced by seeding slow aggregating solutions with preformed aggregates of A beta 42. Taken together, the inhibition of A beta 42 aggregation by A beta 40, the seeding of A beta 40 aggregation by A beta 42 aggregates, and the chemical oxidation of A beta 40 suggest that the relative abundance and

  13. Applications of Remote Sensing

    NASA Astrophysics Data System (ADS)

    Jacha, Charlene

    2015-04-01

    Remote sensing is one of the best ways to be able to monitor and see changes in the Earth. The use of satellite images in the classroom can be a practical way to help students understand the importance and use of remote sensing and Geographic Information Systems (GIS). It is essential in helping students to understand that underlying individual data points are converted to a broad spatial form. The use of actual remote sensing data makes this more understandable to the students e.g. an online map of recent earthquake events, geologic maps, satellite imagery. For change detection, images of years ten or twenty years apart of the same area can be compared and observations recorded. Satellite images of different places can be available on the Internet or from the local space agency. In groups of mixed abilities, students can observe changes in land use over time and also give possible reasons and explanations to those changes. Students should answer essential questions like, how does satellite imagery offer valuable information to different faculties e.g. military, weather, environmental departments and others. Before and after images on disasters for example, volcanoes, floods and earthquakes should be obtained and observed. Key questions would be; how can scientists use these images to predict, or to change the future outcomes over time. How to manage disasters and how the archived images can assist developers in planning land use around that area in the future. Other material that would be useful includes maps and aerial photographs of the area. A flight should be organized over the area for students to acquire aerial photographs of their own; this further enhances their understanding of the concept "remote sensing". Environmental issues such as air, water and land pollution can also be identified on satellite images. Key questions for students would include causes, effects and possible solutions to the problem. Conducting a fieldwork exercise around the area would

  14. REMOTE CONTROLLED SWITCHING DEVICE

    DOEpatents

    Hobbs, J.C.

    1959-02-01

    An electrical switching device which can be remotely controlled and in which one or more switches may be accurately operated at predetermined times or with predetermined intervening time intervals is described. The switching device consists essentially of a deck, a post projecting from the deck at right angles thereto, cam means mounted for rotation around said posts and a switch connected to said deck and actuated by said cam means. Means is provided for rotating the cam means at a constant speed and the switching apparatus is enclosed in a sealed container with external adjusting means and electrical connection elements.

  15. Accelerating Commercial Remote Sensing

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Through the Visiting Investigator Program (VIP) at Stennis Space Center, Community Coffee was able to use satellites to forecast coffee crops in Guatemala. Using satellite imagery, the company can produce detailed maps that separate coffee cropland from wild vegetation and show information on the health of specific crops. The data can control coffee prices and eventually may be used to optimize application of fertilizers, pesticides and irrigation. This would result in maximal crop yields, minimal pollution and lower production costs. VIP is a mechanism involving NASA funding designed to accelerate the growth of commercial remote sensing by promoting general awareness and basic training in the technology.

  16. Remote robotic countermine systems

    NASA Astrophysics Data System (ADS)

    Wells, Peter

    2010-04-01

    QinetiQ North America (QNA) has approximately 27 years experience in the mine/countermine mission area. Our expertise covers mine development, detection, and neutralization and has always been intertwined with deployment of remote robotic systems. Our countermine payload systems have been used to detect limpet mines on ship hulls, antiassault mines in shallow water and littoral zones and currently for clearance and render safe of land-based routes. In our talk, we will address the challenges encountered in addressing the ongoing countermine mission over a diverse range of operational scenarios, environmental conditions and strategic priorities.

  17. Remote sensing program

    NASA Technical Reports Server (NTRS)

    Whitmore, R. A., Jr. (Principal Investigator)

    1980-01-01

    A syllabus and training materials prepared and used in a series of one-day workshops to introduce modern remote sensing technology to selected groups of professional personnel in Vermont are described. Success in using computer compatible tapes, LANDSAT imagery and aerial photographs is reported for the following applications: (1) mapping defoliation of hardwood forests by tent caterpillar and gypsy moth; (2) differentiating conifer species; (3) mapping ground cover of major lake and pond watersheds; (4) inventorying and locating artificially regenerated conifer forest stands; (5) mapping water quality; (6) ascertaining the boat population to quantify recreational activity on lakes and waterways; and (7) identifying potential aquaculture sites.

  18. [Memory disorders in schizophrenia].

    PubMed

    Danion, J M; Peretti, S; Gras-Vincendon, A; Singer, L

    1992-01-01

    The current interest in memory disorders in schizophrenia results from the way perceptions of schizophrenia--whose organic origin is becoming increasingly evident--and memory--according to which there exist not one, but several memories--have developed. Memory disorders in the schizophrenic cannot be considered in isolation from knowledge accumulated in other areas of the cognitive and neuro-sciences; a more detailed understanding of these disorders requires a comparison of the different cognitive approaches, both with each other and with the neurobiological and clinical approaches, so that they can be integrated. Despite numerous methodological and conceptual difficulties, it now appears to have been established that the schizophrenic's memory deficit should be seen in the context of a wider cognitive deficit, that the memory tasks are not all disturbed and that the memory deficit cannot be identified with one specific form of memory. Thus, iconic formation, short-term memory in the traditionally accepted sense and implicit memory are hardly, if at all, affected; in contrast, the early processing of information, working memory and explicit memory are disturbed, probably to the extent that they require the implementation of strategies to organise the information to be memorized. Finally, in certain tasks, such as those evaluating latent inhibition or negative priming, schizophrenics perform better than normal subjects, suggesting that schizophrenics' cognitive deficit is localised. This profile of memory disorders is compatible with a dysfunction predominating in the frontal and temporo-hippocampal regions. Neuroleptics and anticholinergics have opposite effects on cognitive and mnesic performance, which is improved by the former and aggravated by the latter. The influence of clinical symptoms, positive or negative, institutionalisation of patients and chronic tardive dyskinesia is unclear. Among the theoretical proposals put forward to account for the observed

  19. Aggregate breakup in a contracting nozzle.

    PubMed

    Soos, Miroslav; Ehrl, Lyonel; Bäbler, Matthäus U; Morbidelli, Massimo

    2010-01-05

    The breakup of dense aggregates in an extensional flow was investigated experimentally. The flow was realized by pumping the suspension containing the aggregates through a contracting nozzle. Variation of the cluster mass distribution during the breakage process was measured by small-angle light scattering. Because of the large size of primary particles and the dense aggregate structure image analysis was used to determine the shape and structure of the produced fragments. It was found, that neither aggregate structure, characterized by a fractal dimension d(f) = 2.7, nor shape, characterized by an average aspect ratio equal to 1.5, was affected by breakage. Several passes through the nozzle were required to reach the steady state. This is explained by the radial variation of the hydrodynamic stresses at the nozzle entrance, characterized through computational fluid dynamics, which implies that only the fraction of aggregates whose strength is smaller than the local hydrodynamic stress is broken during one pass through the nozzle. Scaling of the steady-state aggregate size as a function of the hydrodynamic stress was used to determine the aggregate strength.

  20. Local aggregation characteristics of microscale blood flows

    NASA Astrophysics Data System (ADS)

    Kaliviotis, Efstathios; Sherwood, Joseph M.; Dusting, Jonathan; Balabani, Stavroula

    2015-11-01

    Erythrocyte aggregation (EA) is an important aspect of microvascular flows affecting blood flow and viscosity. Microscale blood flows have been studied extensively in recent years using computational and microfluidic based approaches. However, the relationship between the local structural characteristics of blood and the velocity field has not been quantified. We report simultaneous measurements of the local velocity, aggregation and haematocrit distributions of human erythrocytes flowing in a microchannel. EA was induced using Dextran and flows were imaged using brightfield microscopy. Local aggregation characteristics were investigated using statistical and edge-detection image processing techniques while velocity profiles were obtained using PIV algorithms. Aggregation intensity was found to strongly correlate with local variations in velocity in both the central and wall regions of the channel. The edge detection method showed that near the side wall large aggregates are associated with high local velocities and low local shear rates. In the central region large aggregates occurred in regions of low velocity and high erythrocyte concentration. The results demonstrate the combined effect of haematocrit and velocity distributions on local aggregation characteristics.

  1. Protein aggregation in a membrane environment.

    PubMed

    Gorbenko, Galyna; Trusova, Valeriya

    2011-01-01

    Biological membranes are featured by a remarkable ability to modulate a wide range of physiological and pathological processes. Of these, protein aggregation is currently receiving the greatest attention, as one type of the ordered protein aggregates, amyloid fibrils, proved to be involved in molecular etiology of a number of fatal diseases. It has been hypothesized that nucleation of amyloid fibrils and toxic action of their precursors is mediated by lipid-protein interactions. Lipid bilayer provides a variety of environments in which aggregated state of polypeptide chain appears to be more thermodynamically favorable than its monomeric form. The major factors responsible for the enhanced self-association propensity of membrane-bound proteins include (i) structural transition of polypeptide chain into aggregation-prone conformation; (ii) protein crowding in a lipid phase; (iii) particular aggregation-favoring orientation and bilayer embedment of the protein molecules. All these factors are considered in the present review with an emphasis being put on the role of electrostatic, hydrophobic, and hydrogen-bonding phenomena in initiating and modulating the protein aggregation on a membrane template. Likewise, we survey the advanced experimental techniques employed for detection and structural characterization of the aggregated species in membrane systems.

  2. Remote Data Access with IDL

    NASA Technical Reports Server (NTRS)

    Galloy, Michael

    2013-01-01

    A tool based on IDL (Interactive Data Language) and DAP (Data Access Protocol) has been developed for user-friendly remote data access. A difficulty for many NASA researchers using IDL is that often the data to analyze are located remotely and are too large to transfer for local analysis. Researchers have developed a protocol for accessing remote data, DAP, which is used for both SOHO and STEREO data sets. Server-side side analysis via IDL routine is available through DAP.

  3. Laser Remote Sensing at NASA

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.

    2005-01-01

    NASA is developing active remote sensors to monitor the health of Planet Earth and for exploration of other planets. Development and deployment of these remote sensors can have a huge economic impact. Lasers for these active remote sensors span the spectral range from the ultraviolet to the mid infrared spectral regions. Development activities range from quantum mechanical modeling and prediction of new laser materials to the design, development, and demonstration be deployed in the field.

  4. Physical fundamentals of remote sensing

    NASA Astrophysics Data System (ADS)

    Schanda, E.

    The physical principles describing the propagation of EM waves in the atmosphere and their interactions with matter are discussed as they apply to remote sensing, in an introductory text intended for graduate science students, environmental-science researchers, and remote-sensing practitioners. The emphasis is on basic effects rather than an specific remote-sensing techniques or observational results. Chapters are devoted to basic relations, the spectral lines of atmospheric gases, the spectral properties of condensed matter, and radiative transfer.

  5. Seasonal variability of soil aggregate stability

    NASA Astrophysics Data System (ADS)

    Rohoskova, M.; Kodesova, R.; Jirku, V.; Zigova, A.; Kozak, J.

    2009-04-01

    Seasonal variability of soil properties measured in surface horizons of three soil types (Haplic Luvisol, Greyic Phaeozem, Haplic Cambisol) was studied in years 2007 and 2008. Undisturbed and disturbed soil samples were taken every month to evaluate field water content, bulk density, porosity, ration of gravitational and capillary pores, pHKCl and pHH2O, organic matter content and its quality, aggregate stability using WSA index. In addition, micromorphological features of soil aggregates were studied in thin soil sections that were made from undisturbed large soil aggregates. Results showed that soil aggregate stability depended on stage of the root zone development, soil management and climatic conditions. Larger aggregate stabilities and also larger ranges of measure values were obtained in the year 2007 then those measured in 2008. This was probably caused by lower precipitations and consequently lower soil water contents observed in 2007 than those measured in 2008. The highest aggregate stability was measured at the end of April in the years 2007 and 2008 in Haplic Luvisol and Greyic Phaeozem, and at the end of June in the year 2007 and at the beginning of June in 2008 in Haplic Cambisol. In all cases aggregate stability increased during the root growth and then gradually decreased due to summer rainfall events. Aggregate stability reflected aggregate structure and soil pore system development, which was documented on micromorphological images and evaluated using the ration of gravitational and capillary pores measured on the undisturbed sol samples. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of the Czech Republic grant No. 526/08/0434, and the Ministry of Education, Youth and Sports grant No. MSM 6046070901.

  6. Creep of dry clinopyroxene aggregates

    NASA Astrophysics Data System (ADS)

    Bystricky, Misha; Mackwell, Stephen

    2001-01-01

    We have determined diffusional and dislocation creep rheologies for clinopyroxenite Ca1.0Mg0.8Fe0.2Si2O6 under dry conditions by deforming natural and hot-pressed samples at confining pressures of 300-430 MPa and temperatures of 1100°-1250°C with the oxygen fugacity buffered by either nickel-nickel oxide or iron-wüstite powders. The coarse-grained natural Sleaford Bay clinopyroxenite yielded a stress exponent of n = 4.7 ± 0.2 and an activation energy for creep of Q = 760 ± 40 kJ mol-1, consistent with deformation in the dislocation creep regime. The strength of the natural clinopyroxenite is consistent with previous high-temperature measurements of dislocation creep behavior of Sleaford Bay clinopyroxenite by Kirby and Kronenberg [1984] and Boland and Tullis [1986]. Fine-grained clinopyroxenite was prepared from ground powders of the natural clinopyroxenite. Hot-pressed samples were deformed under similar conditions to the natural samples. Mixed-mode deformation behavior was observed, with diffusional creep (n = 1) at lower differential stresses and dislocation creep (with n and Q similar to those of the natural samples) at higher differential stresses. Within the dislocation creep field the predried hot-pressed samples generally yielded creep rates that were about an order of magnitude faster than the natural samples. Thus, even at the highest differential stresses, a component of strain accommodation by grain boundary diffusion was present in the hot-pressed samples. Optical and electron microscope investigations of the deformation microstructures of the natural and hot-pressed samples show evidence for mechanical twinning and activation of dislocation slip systems. When extrapolated to geological conditions expected in the deep crust and upper mantle on Earth and other terrestrial planets, the strength of dry single-phase clinopyroxene aggregates is very high, exceeding that of dry olivine-rich rocks.

  7. Applied Remote Sensing Program (ARSP)

    NASA Technical Reports Server (NTRS)

    Johnson, J. D.; Foster, K. E.; Mouat, D. A.; Miller, D. A.; Conn, J. S.

    1976-01-01

    The activities and accomplishments of the Applied Remote Sensing Program during FY 1975-1976 are reported. The principal objective of the Applied Remote Sensing Program continues to be designed projects having specific decision-making impacts as a principal goal. These projects are carried out in cooperation and collaboration with local, state and federal agencies whose responsibilities lie with planning, zoning and environmental monitoring and/or assessment in the application of remote sensing techniques. The end result of the projects is the use by the involved agencies of remote sensing techniques in problem solving.

  8. On aggregation in spatial econometric modelling

    NASA Astrophysics Data System (ADS)

    Paelinck, Jean H. P.

    The spatial aggregation problem - also termed the modifiable areal unit problem - has attracted regular attention in spatial statistics and econometrics. In this study econometric aggregation analysis is used to investigate the formal composition of meso-areal parameters given micro-areal underlying relations with spatial dependence. Impact on stochastic terms (possible meso-areal spatial autocorrelation) is also studied. Finally consequences for meso-areal estimation are derived, the general finding having been that spatial aggregation leads to meso-region specific parameter values, with the estimation problems this implies.

  9. Directional sensing and streaming in Dictyostelium aggregation

    NASA Astrophysics Data System (ADS)

    Almeida, Sofia; Dilão, Rui

    2016-05-01

    We merge the Kessler-Levine simple discrete model for Dictyostelium cyclic adenosine monophosphate (cAMP) production and diffusion with the Dilão-Hauser directional sensing aggregation mechanism. The resulting compound model describes all the known transient patterns that emerge during Dictyostelium aggregation, which include the spontaneous formation of cAMP self-sustained target and spiral waves and streaming. We show that the streaming patterns depend on the speed of the amoebae, on the relaxation time for the production of cAMP, on the cAMP degradation rate, and on directional sensing. Moreover, we show that different signaling centers emerge during Dictyostelium aggregation.

  10. A look at construction aggregates production

    USGS Publications Warehouse

    Willett, Jason Christopher

    2009-01-01

    Construction aggregates are defined as the combination of crushed stone and construction sand and gravel. Aggregates are one of the most accessible natural resources on Earth and one of the fundamental building blocks of our society. They have been used from the earliest times of our civilization for a variety of applications that have increased in number and complexity with time and technological progress. Despite the relatively low but increasing unit value of its basic products, the construction aggregates industry is a major contributor to and an indicator of the economic well-being of the nation.

  11. Reusing recycled aggregates in structural concrete

    NASA Astrophysics Data System (ADS)

    Kou, Shicong

    The utilization of recycled aggregates in concrete can minimize environmental impact and reduce the consumption of natural resources in concrete applications. The aim of this thesis is to provide a scientific basis for the possible use of recycled aggregates in structure concrete by conducting a comprehensive programme of laboratory study to gain a better understanding of the mechanical, microstructure and durability properties of concrete produced with recycled aggregates. The study also explored possible techniques to of improve the properties of recycled aggregate concrete that is produced with high percentages (≧ 50%) of recycled aggregates. These techniques included: (a) using lower water-to-cement ratios in the concrete mix design; (b) using fly ash as a cement replacement or as an additional mineral admixture in the concrete mixes, and (c) precasting recycled aggregate concrete with steam curing regimes. The characteristics of the recycled aggregates produced both from laboratory and a commercially operated pilot construction and demolition (C&D) waste recycling plant were first studied. A mix proportioning procedure was then established to produce six series of concrete mixtures using different percentages of recycled coarse aggregates with and without the use of fly ash. The water-to-cement (binder) ratios of 0.55, 0.50, 0.45 and 0.40 were used. The fresh properties (including slump and bleeding) of recycled aggregate concrete (RAC) were then quantified. The effects of fly ash on the fresh and hardened properties of RAC were then studied and compared with those RAC prepared with no fly ash addition. Furthermore, the effects of steam curing on the hardened properties of RAC were investigated. For micro-structural properties, the interfacial transition zones of the aggregates and the mortar/cement paste were analyzed by SEM and EDX-mapping. Moreover, a detailed set of results on the fracture properties for RAC were obtained. Based on the experimental

  12. Exciton dynamics in perturbed vibronic molecular aggregates

    PubMed Central

    Brüning, C.; Wehner, J.; Hausner, J.; Wenzel, M.; Engel, V.

    2015-01-01

    A site specific perturbation of a photo-excited molecular aggregate can lead to a localization of excitonic energy. We investigate this localization dynamics for laser-prepared excited states. Changing the parameters of the electric field significantly influences the exciton localization which offers the possibility for a selective control of this process. This is demonstrated for aggregates possessing a single vibrational degree of freedom per monomer unit. It is shown that the effects identified for the molecular dimer can be generalized to larger aggregates with a high density of vibronic states. PMID:26798840

  13. Multiple-User, Multitasking, Virtual-Memory Computer System

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.; Roth, Don J.; Stang, David B.

    1993-01-01

    Computer system designed and programmed to serve multiple users in research laboratory. Provides for computer control and monitoring of laboratory instruments, acquisition and anlaysis of data from those instruments, and interaction with users via remote terminals. System provides fast access to shared central processing units and associated large (from megabytes to gigabytes) memories. Underlying concept of system also applicable to monitoring and control of industrial processes.

  14. 76 FR 56810 - Controlled Substances: 2011 Proposed Aggregate Production Quotas

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... Enforcement Administration Controlled Substances: 2011 Proposed Aggregate Production Quotas AGENCY: Drug...: This notice proposes to adjust the 2011 aggregate production quotas for several controlled substances... aggregate production quotas for five synthetic cannabinoids temporarily controlled in Schedule I....

  15. Distributed multiport memory architecture

    NASA Technical Reports Server (NTRS)

    Kohl, W. H. (Inventor)

    1983-01-01

    A multiport memory architecture is diclosed for each of a plurality of task centers connected to a command and data bus. Each task center, includes a memory and a plurality of devices which request direct memory access as needed. The memory includes an internal data bus and an internal address bus to which the devices are connected, and direct timing and control logic comprised of a 10-state ring counter for allocating memory devices by enabling AND gates connected to the request signal lines of the devices. The outputs of AND gates connected to the same device are combined by OR gates to form an acknowledgement signal that enables the devices to address the memory during the next clock period. The length of the ring counter may be effectively lengthened to any multiple of ten to allow for more direct memory access intervals in one repetitive sequence. One device is a network bus adapter which serially shifts onto the command and data bus, a data word (8 bits plus control and parity bits) during the next ten direct memory access intervals after it has been granted access. The NBA is therefore allocated only one access in every ten intervals, which is a predetermined interval for all centers. The ring counters of all centers are periodically synchronized by DMA SYNC signal to assure that all NBAs be able to function in synchronism for data transfer from one center to another.

  16. [Learning and memory].

    PubMed

    Lombroso, Paul

    2004-09-01

    Memory is broadly divided into declarative and nondeclarative forms of memory. The hippocampus is required for the formation of declarative memories, while a number of other brain regions including the striatum, amygdala and nucleus accumbens are involved in the formation of nondeclarative memories. The formation of all memories require morphological changes of synapses: new ones must be formed or old ones strengthened. These changes are thought to reflect the underlying cellular basis for persistent memories. Considerable advances have occurred over the last decade in our understanding of the molecular bases of how these memories are formed. A key regulator of synaptic plasticity is a signaling pathway that includes the mitogen activated protein (MAP) kinase. As this pathway is required for normal memory and learning, it is not surprising that mutations in members of this pathway lead to disruptions in learning. Neurofibromatosis, Coffin-Lowry syndrome and Rubinstein-Taybi syndrome are three examples of developmental disorders that have mutations in key components of the MAP kinase signaling pathway.

  17. Memory and Aging

    MedlinePlus

    ... or home environment and you’re not paying attention when your friend gives you directions to her new home, you will not be able to recall how to get there. Memory and Aging Memory Aids Keep “to do” lists Keep “to do” lists and ...

  18. Regret as Autobiographical Memory

    ERIC Educational Resources Information Center

    Davison, Ian M.; Feeney, Aidan

    2008-01-01

    We apply an autobiographical memory framework to the study of regret. Focusing on the distinction between regrets for specific and general events we argue that the temporal profile of regret, usually explained in terms of the action-inaction distinction, is predicted by models of autobiographical memory. In two studies involving participants in…

  19. Memories of Physical Education

    ERIC Educational Resources Information Center

    Sidwell, Amy M.; Walls, Richard T.

    2014-01-01

    The purpose of this investigation was to explore college students' autobiographical memories of physical education (PE). Questionnaires were distributed to students enrolled in undergraduate Introduction to PE and Introduction to Communications courses. The 261 participants wrote about memories of PE. These students recalled events from Grades…

  20. Predicting Reasoning from Memory

    ERIC Educational Resources Information Center

    Heit, Evan; Hayes, Brett K.

    2011-01-01

    In an effort to assess the relations between reasoning and memory, in 8 experiments, the authors examined how well responses on an inductive reasoning task are predicted from responses on a recognition memory task for the same picture stimuli. Across several experimental manipulations, such as varying study time, presentation frequency, and the…

  1. Experimental Optoelectronic Associative Memory

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin

    1992-01-01

    Optoelectronic associative memory responds to input image by displaying one of M remembered images. Which image to display determined by optoelectronic analog computation of resemblance between input image and each remembered image. Does not rely on precomputation and storage of outer-product synapse matrix. Size of memory needed to store and process images reduced.

  2. Memorial symptom assessment scale.

    PubMed

    Chang, Victor T; Hwang, Shirley S; Thaler, Howard T; Kasimis, Basil S; Portenoy, Russell K

    2004-04-01

    Patients with advanced illnesses often have multiple symptoms. As interest in palliative care and interventions for symptom control increase, the ability to assess multiple symptoms has become more important. A number of instruments have been developed to meet this need in cancer patients. This article reviews the development and applications of a multidimensional instrument, the Memorial Symptom Assessment Scale. The Memorial Symptom Assessment Scale has 32 symptoms and three dimensions of frequency, severity, and distress. Shorter versions - The Memorial Symptom Assessment Scale Short Form (32 symptoms with one dimension) and the Condensed Memorial Symptom Assessment Scale (14 symptoms with one dimension), and a version for children aged 7-12 years, have also been developed. A distinctive feature is the summary subscales for physical distress, psychological distress, and The Global Distress Index. The Memorial Symptom Assessment Scale has proven useful in description of symptom epidemiology, the role of symptoms in pain, fatigue, and spirituality; as a predictor of survival, and in proxy assessments of pain. The Memorial Symptom Assessment Scale has been used in studies of cancer and AIDS patients, and patients with advanced medical illnesses. Possible future roles of instruments such as the Memorial Symptom Assessment Scale include use in clinical trials, for pharmacoeconomic analyses, definition of symptom clusters and symptom burden, the development of symptom outcome measures, symptom monitoring, and improving care for patients. Continued research is needed for the versions of the Memorial Symptom Assessment Scale and other symptom instruments in different populations and applications.

  3. Visual Memory at Birth.

    ERIC Educational Resources Information Center

    Slater, Alan; And Others

    1982-01-01

    Explored new-born babys' capacity for forming visual memories. Used an habituation procedure that accommodated individual differences by allowing each infant to control the time course of habituation trials. Found significant novelty preference, providing strong evidence that recognition memory can be reliably demonstrated from birth. (Author/JAC)

  4. Human Learning and Memory

    ERIC Educational Resources Information Center

    Lieberman, David A.

    2012-01-01

    This innovative textbook is the first to integrate learning and memory, behaviour, and cognition. It focuses on fascinating human research in both memory and learning (while also bringing in important animal studies) and brings the reader up to date with the latest developments in the subject. Students are encouraged to think critically: key…

  5. Human Memory: The Basics

    ERIC Educational Resources Information Center

    Martinez, Michael E.

    2010-01-01

    The human mind has two types of memory: short-term and long-term. In all types of learning, it is best to use that structure rather than to fight against it. One way to do that is to ensure that learners can fit new information into patterns that can be stored in and more easily retrieved from long-term memory.

  6. Memory Efficient Ranking.

    ERIC Educational Resources Information Center

    Moffat, Alistair; And Others

    1994-01-01

    Describes an approximate document ranking process that uses a compact array of in-memory, low-precision approximations for document length. Combined with another rule for reducing the memory required by partial similarity accumulators, the approximation heuristic allows the ranking of large document collections using less than one byte of memory…

  7. Memory technology survey

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The current status of semiconductor, magnetic, and optical memory technologies is described. Projections based on these research activities planned for the shot term are presented. Conceptual designs of specific memory buffer pplications employing bipola, CMOS, GaAs, and Magnetic Bubble devices are discussed.

  8. An Exceptional Memory

    ERIC Educational Resources Information Center

    Hunter, Ian M. L.

    1977-01-01

    An account is given of the exceptional memory of the late Professor A. C. Aitken who was also a distinguished mathematician and mental calculator. Compared with Shereshevskii, another man with exceptional memory, he shows the scholar's reliance on conceptual mapping rather than the mnemonist's reliance on perceptual chaining. (Editor)

  9. Memory Metals (Marchon Eyewear)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Another commercial application of memory metal technology is found in a "smart" eyeglass frame that remembers its shape and its wearer's fit. A patented "memory encoding process" makes this possible. Heat is not required to return the glasses to shape. A large commercial market is anticipated.

  10. A Space for Memory

    ERIC Educational Resources Information Center

    Charman, Karen

    2015-01-01

    In this article I examine the possibilities of reparation in an era of privatisation and de-industrialisation. I examine the effect of a recent project Sunshine Memory Space, a space, designed to evoke memories of a de-industrialised urban Melbourne suburb Sunshine. This project offered the opportunity for the effects of industrial change to be…

  11. Managing Meetings...Remotely

    NASA Technical Reports Server (NTRS)

    Woodward, Hugh

    2005-01-01

    Remote meetings are best for updates and information sharing, but it is possible to effectively facilitate decisions with a little planning. Generally, the meeting leader needs to clearly state the proposed decision and then separately poll each participant for concurrence. Normally, there will be a range of responses, requiring the facilitator to restate the proposal and repeat the process. Several iterations may be required before a consensus is achieved. I usually confirm decisions by restating the conclusion as it will appear in the meeting notes and asking the participants to express any objections. Gaining commitment to follow-up actions is never easy, of course, but tends to be particularly tricky in remote meetings. The ideal solution is to use collaboration software with a whiteboard as a means of recording the follow-up actions and responsibilities. (A Word or Excel document viewed through NetMeeting works equally well.) But if the meeting is being conducted without collaboration software, the leader must review each follow-up action explicitly, even painstakingly. I generally note follow-up actions throughout the meeting and use the last few minutes to confirm and finalize. I read each action and name the person I think owns the responsibility. When the person accepts, I validate by asking for a completion date. All the normal rules for assigning follow-up actions apply, of course. One, and only one, person must be responsible for each action, and assigning an action to somebody not present is akin to assigning it to nobody.

  12. Animal models of source memory.

    PubMed

    Crystal, Jonathon D

    2016-01-01

    Source memory is the aspect of episodic memory that encodes the origin (i.e., source) of information acquired in the past. Episodic memory (i.e., our memories for unique personal past events) typically involves source memory because those memories focus on the origin of previous events. Source memory is at work when, for example, someone tells a favorite joke to a person while avoiding retelling the joke to the friend who originally shared the joke. Importantly, source memory permits differentiation of one episodic memory from another because source memory includes features that were present when the different memories were formed. This article reviews recent efforts to develop an animal model of source memory using rats. Experiments are reviewed which suggest that source memory is dissociated from other forms of memory. The review highlights strengths and weaknesses of a number of animal models of episodic memory. Animal models of source memory may be used to probe the biological bases of memory. Moreover, these models can be combined with genetic models of Alzheimer's disease to evaluate pharmacotherapies that ultimately have the potential to improve memory.

  13. Is random access memory random?

    NASA Technical Reports Server (NTRS)

    Denning, P. J.

    1986-01-01

    Most software is contructed on the assumption that the programs and data are stored in random access memory (RAM). Physical limitations on the relative speeds of processor and memory elements lead to a variety of memory organizations that match processor addressing rate with memory service rate. These include interleaved and cached memory. A very high fraction of a processor's address requests can be satified from the cache without reference to the main memory. The cache requests information from main memory in blocks that can be transferred at the full memory speed. Programmers who organize algorithms for locality can realize the highest performance from these computers.

  14. Structure and kinetics of shear aggregation in turbulent flows. I. Early stage of aggregation.

    PubMed

    Bäbler, Matthäus U; Moussa, Amgad S; Soos, Miroslav; Morbidelli, Massimo

    2010-08-17

    Aggregation of rigid colloidal particles leads to fractal-like structures that are characterized by a fractal dimension d(f) which is a key parameter for describing aggregation processes. This is particularly true in shear aggregation where d(f) strongly influences aggregation kinetics. Direct measurement of d(f) in the early stages of shear aggregation is however difficult, as the aggregates are small and few in number. An alternative method for determining d(f) is to use an aggregation model that when fitted to the time evolution of the cluster mass distribution allows for estimating d(f). Here, we explore three such models, two of which are based on an effective collision sphere and one which directly incorporates the permeable structure of the aggregates, and we apply them for interpreting the initial aggregate growth measured experimentally in a turbulent stirred tank reactor. For the latter, three polystyrene latexes were used that differed only in the size of the primary particles (d(p) = 420, 600, and 810 nm). It was found that all three models describe initial aggregation kinetics reasonably well using, however, substantially different values for d(f). To discriminate among the models, we therefore also studied the regrowth of preformed aggregates where d(f) was experimentally accessible. It was found that only the model that directly incorporates the permeable structure of the aggregates is able to predict correctly this second type of experiments. Applying this model to the initial aggregation kinetics, we conclude that the actual initial fractal dimension is d(f) = 2.07 +/- 0.04 as found from this model.

  15. Aggregate structure, morphology and the effect of aggregation mechanisms on viscosity at elevated protein concentrations.

    PubMed

    Barnett, Gregory V; Qi, Wei; Amin, Samiul; Neil Lewis, E; Roberts, Christopher J

    2015-12-01

    Non-native aggregation is a common issue in a number of degenerative diseases and during manufacturing of protein-based therapeutics. There is a growing interest to monitor protein stability at intermediate to high protein concentrations, which are required for therapeutic dosing of subcutaneous injections. An understanding of the impact of protein structural changes and interactions on the protein aggregation mechanisms and resulting aggregate size and morphology may lead to improved strategies to reduce aggregation and solution viscosity. This report investigates non-native aggregation of a model protein, α-chymotrypsinogen, under accelerated conditions at elevated protein concentrations. Far-UV circular dichroism and Raman scattering show structural changes during aggregation. Size exclusion chromatography and laser light scattering are used to monitor the progression of aggregate growth and monomer loss. Monomer loss is concomitant with increased β-sheet structures as monomers are added to aggregates, which illustrate a transition from a native monomeric state to an aggregate state. Aggregates grow predominantly through monomer-addition, resulting in a semi-flexible polymer morphology. Analysis of aggregation growth kinetics shows that pH strongly affects the characteristic timescales for nucleation (τn) and growth (τg), while the initial protein concentration has only minor effects on τn or τg. Low-shear viscosity measurements follow a common scaling relationship between average aggregate molecular weight (Mw(agg)) and concentration (σ), which is consistent with semi-dilute polymer-solution theory. The results establish a link between aggregate growth mechanisms, which couple Mw(agg) and σ, to increases in solution viscosity even at these intermediate protein concentrations (less than 3w/v %).

  16. Applications of Remote Sensing to Emergency Management.

    DTIC Science & Technology

    1980-02-15

    Contents: Foundations of Remote Sensing : Data Acquisition and Interpretation; Availability of Remote Sensing Technology for Disaster Response...Imaging Systems, Current and Near Future Satellite and Aircraft Remote Sensing Systems; Utilization of Remote Sensing in Disaster Response: Categories of...Disasters, Phases of Monitoring Activities; Recommendations for Utilization of Remote Sensing Technology in Disaster Response; Selected Reading List.

  17. Predicting reasoning from memory.

    PubMed

    Heit, Evan; Hayes, Brett K

    2011-02-01

    In an effort to assess the relations between reasoning and memory, in 8 experiments, the authors examined how well responses on an inductive reasoning task are predicted from responses on a recognition memory task for the same picture stimuli. Across several experimental manipulations, such as varying study time, presentation frequency, and the presence of stimuli from other categories, there was a high correlation between reasoning and memory responses (average r = .87), and these manipulations showed similar effects on the 2 tasks. The results point to common mechanisms underlying inductive reasoning and recognition memory abilities. A mathematical model, GEN-EX (generalization from examples), derived from exemplar models of categorization, is presented, which predicts both reasoning and memory responses from pairwise similarities among the stimuli, allowing for additional influences of subtyping and deterministic responding.

  18. Computer memory management system

    DOEpatents

    Kirk, III, Whitson John

    2002-01-01

    A computer memory management system utilizing a memory structure system of "intelligent" pointers in which information related to the use status of the memory structure is designed into the pointer. Through this pointer system, The present invention provides essentially automatic memory management (often referred to as garbage collection) by allowing relationships between objects to have definite memory management behavior by use of coding protocol which describes when relationships should be maintained and when the relationships should be broken. In one aspect, the present invention system allows automatic breaking of strong links to facilitate object garbage collection, coupled with relationship adjectives which define deletion of associated objects. In another aspect, The present invention includes simple-to-use infinite undo/redo functionality in that it has the capability, through a simple function call, to undo all of the changes made to a data model since the previous `valid state` was noted.

  19. Memory B cells.

    PubMed

    Kurosaki, Tomohiro; Kometani, Kohei; Ise, Wataru

    2015-03-01

    The immune system can remember a previously experienced pathogen and can evoke an enhanced response to reinfection that depends on memory lymphocyte populations. Recent advances in tracking antigen-experienced memory B cells have revealed the existence of distinct classes of cells that have considerable functional differences. Some of these differences seem to be determined by the stimulation history during memory cell formation. To induce rapid recall antibody responses, the contributions of other types of cells, such as memory T follicular helper cells, have also now begun to be appreciated. In this Review, we discuss these and other recent advances in our understanding of memory B cells, focusing on the underlying mechanisms that are required for rapid and effective recall antibody responses.

  20. Serotonin transporter and memory.

    PubMed

    Meneses, Alfredo; Perez-Garcia, Georgina; Ponce-Lopez, Teresa; Tellez, Ruth; Castillo, Carlos

    2011-09-01

    The serotonin transporter (SERT) has been associated to diverse functions and diseases, though seldom to memory. Therefore, we made an attempt to summarize and discuss the available publications implicating the involvement of the SERT in memory, amnesia and anti-amnesic effects. Evidence indicates that Alzheimer's disease and drugs of abuse like d-methamphetamine (METH) and (+/-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") have been associated to decrements in the SERT expression and memory deficits. Several reports have indicated that memory formation and amnesia affected the SERT expression. The SERT expression seems to be a reliable neural marker related to memory mechanisms, its alterations and potential treatment. The pharmacological, neural and molecular mechanisms associated to these changes are of great importance for investigation.

  1. Cosmological memory effect

    NASA Astrophysics Data System (ADS)

    Tolish, Alexander; Wald, Robert M.

    2016-08-01

    The "memory effect" is the permanent change in the relative separation of test particles resulting from the passage of gravitational radiation. We investigate the memory effect for a general, spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology by considering the radiation associated with emission events involving particle-like sources. We find that if the resulting perturbation is decomposed into scalar, vector, and tensor parts, only the tensor part contributes to memory. Furthermore, the tensor contribution to memory depends only on the cosmological scale factor at the source and observation events, not on the detailed expansion history of the universe. In particular, for sources at the same luminosity distance, the memory effect in a spatially flat FLRW spacetime is enhanced over the Minkowski case by a factor of (1 +z ).

  2. Imaging autobiographical memory.

    PubMed

    Fossati, Philippe

    2013-12-01

    Autobiographical memory (AM) defines the memory systems that encode, consolidate, and retrieve personal events and facts, AM is strongly related to self-perception and self representation. We review here the neural correlates of AM retrieval. AM retrieval encompasses a large neural network including the prefrontal, temporal, and parietal cortex, and limbic structures. All these regions subserve the cognitive processes (episodic remembering, cognitive control, self-processing, and scene construction) at play during memory retrieval. We emphasize the specific role of medial prefrontal cortex and precuneus in self-processing during autobiographical memory retrieval. Overall, these data call for further studies in psychiatric patients, to investigate the neural underpinnings of autobiographical memory and self-representation in mental disorders.

  3. Innate Memory T cells

    PubMed Central

    Jameson, Stephen C.; Lee, You Jeong; Hogquist, Kristin A.

    2015-01-01

    Memory T cells are usually considered to be a feature of a successful immune response against a foreign antigen, and such cells can mediate potent immunity. However, in mice, alternative pathways have been described, through which naïve T cells can acquire the characteristics and functions of memory T cells without encountering specific foreign antigen or the typical signals required for conventional T cell differentiation. Such cells reflect a response to the internal rather the external environment, and hence such cells are called innate memory T cells. In this review, we describe how innate memory subsets were identified, the signals that induce their generation and their functional properties and potential role in the normal immune response. The existence of innate memory T cells in mice raises questions about whether parallel populations exist in humans, and we discuss the evidence for such populations during human T cell development and differentiation. PMID:25727290

  4. A wavelet based investigation of long memory in stock returns

    NASA Astrophysics Data System (ADS)

    Tan, Pei P.; Galagedera, Don U. A.; Maharaj, Elizabeth A.

    2012-04-01

    Using a wavelet-based maximum likelihood fractional integration estimator, we test long memory (return predictability) in the returns at the market, industry and firm level. In an analysis of emerging market daily returns over the full sample period, we find that long-memory is not present and in approximately twenty percent of 175 stocks there is evidence of long memory. The absence of long memory in the market returns may be a consequence of contemporaneous aggregation of stock returns. However, when the analysis is carried out with rolling windows evidence of long memory is observed in certain time frames. These results are largely consistent with that of detrended fluctuation analysis. A test of firm-level information in explaining stock return predictability using a logistic regression model reveal that returns of large firms are more likely to possess long memory feature than in the returns of small firms. There is no evidence to suggest that turnover, earnings per share, book-to-market ratio, systematic risk and abnormal return with respect to the market model is associated with return predictability. However, degree of long-range dependence appears to be associated positively with earnings per share, systematic risk and abnormal return and negatively with book-to-market ratio.

  5. Electrophysiological evidence for strategically orienting retrieval toward the specific age of a memory.

    PubMed

    Johnson, Jeffrey D; McGhee, Anna K

    2015-11-01

    For over a century, memory researchers have extensively studied the differences between retrieving memories that were encoded in the remote past as opposed to recently. Although this work has largely focused on the changes that these memory traces undergo over time, an unexplored issue is whether retrieval attempts and other strategic processes might be differentially oriented in order to effectively access memories of different ages. The current study addressed this issue by instructing participants to retrieve words that were encoded either one week (remote) or about 30 minutes earlier (recent). To maximize the possibility that participants adopted distinct retrieval orientations, separate blocks of the memory test employed exclusion task procedures in which the words from only one encoding period were targeted at a given time, in the face of distractors from the other period. Event-related potentials (ERPs) elicited by correctly-rejected new items were contrasted to minimize confounding effects of retrieval success. The new-item ERPs revealed differences according to the targeted week, such that the ERPs over posterior scalp were more positive-going for the recent compared to remote blocks. Furthermore, using multiple methods, these ERP effects were dissociated from differences in difficulty across the two conditions. The findings provide novel evidence that knowledge about when a memory was initially encoded leads to differences in the adoption of retrieval processing strategies.

  6. 32 CFR 701.46 - Aggregating requests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... avoiding the assessment of fees, the activity may aggregate any such requests and charge accordingly. One... period however, such a presumption becomes harder to sustain and activities should have a solid basis...

  7. 32 CFR 701.46 - Aggregating requests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... avoiding the assessment of fees, the activity may aggregate any such requests and charge accordingly. One... period however, such a presumption becomes harder to sustain and activities should have a solid basis...

  8. 32 CFR 701.46 - Aggregating requests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... avoiding the assessment of fees, the activity may aggregate any such requests and charge accordingly. One... period however, such a presumption becomes harder to sustain and activities should have a solid basis...

  9. 32 CFR 701.46 - Aggregating requests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... avoiding the assessment of fees, the activity may aggregate any such requests and charge accordingly. One... period however, such a presumption becomes harder to sustain and activities should have a solid basis...

  10. Salt-induced aggregation of stiff polyelectrolytes.

    PubMed

    Fazli, Hossein; Mohammadinejad, Sarah; Golestanian, Ramin

    2009-10-21

    Molecular dynamics simulation techniques are used to study the process of aggregation of highly charged stiff polyelectrolytes due to the presence of multivalent salt. The dominant kinetic mode of aggregation is found to be the case of one end of one polyelectrolyte meeting others at right angles, and the kinetic pathway to bundle formation is found to be similar to that of flocculation dynamics of colloids as described by Smoluchowski. The aggregation process is found to favor the formation of finite bundles of 10-11 filaments at long times. Comparing the distribution of the cluster sizes with the Smoluchowski formula suggests that the energy barrier for the aggregation process is negligible. Also, the formation of long-lived metastable structures with similarities to the raft-like structures of actin filaments is observed within a range of salt concentration.

  11. Active matter model of Myxococcus xanthus aggregation

    NASA Astrophysics Data System (ADS)

    Patch, Adam; Bahar, Fatmagul; Liu, Guannan; Thutupalli, Shashi; Welch, Roy; Yllanes, David; Shaevitz, Joshua; Marchetti, M. Cristina

    Myxococcus xanthus is a soil-dwelling bacterium that exhibits several fascinating collective behaviors including streaming, swarming, and generation of fruiting bodies. A striking feature of M. xanthus is that it periodically reverses its motility direction. The first stage of fruiting body formation is characterized by the aggregation of cells on a surface into round mesoscopic structures. Experiments have shown that this aggregation relies heavily on regulation of the reversal rate and local mechanical interactions, suggesting motility-induced phase separation may play an important role. We have adapted self-propelled particle models to include cell reversal and motility suppression resulting from sporulation observed in aggregates. Using 2D molecular dynamics simulations, we map the phase behavior in the space of Péclet number and local density and examine the kinetics of aggregation for comparison to experiments.

  12. 24 CFR 55.24 - Aggregation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain Management § 55.24 Aggregation... same floodplain, and are currently under review by the Department (or by a grant recipient subject...

  13. 24 CFR 55.24 - Aggregation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain Management § 55.24 Aggregation... same floodplain, and are currently under review by the Department (or by a grant recipient subject...

  14. 24 CFR 55.24 - Aggregation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain Management § 55.24 Aggregation... same floodplain, and are currently under review by the Department (or by a grant recipient subject...

  15. 24 CFR 55.24 - Aggregation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain Management § 55.24 Aggregation... same floodplain, and are currently under review by the Department (or by a grant recipient subject...

  16. Nanoscale Ionic Aggregate Morphology in Zwitterionic Copolymers

    NASA Astrophysics Data System (ADS)

    Choi, Jae-Hong; Huyck, Rebecca; Salas-de La Cruz, David; Long, Timothy E.; Winey, Karen I.

    2009-03-01

    The morphology of two different zwitterionic copolymers, poly(sulfobetaine methacrylate-ran-butyl acrylate), and poly(sulfobetaine methacrylamide-ran-butyl acrylate) are investigated as a function of the mol % content of SBMA (7 and 9 mol %) and SBMAm (6, 10 and 13 mol %), respectively. In both copolymers, X-ray scattering results show a new structure in the material arising from ionic aggregates. The sizes of the ionic aggregates are obtained through the scattering model. The sizes of the ionic aggregates increase as the ion content increases. The application of scanning transmission electron microscopy to the study of ionomer morphology has enabled direct, model-independent visualization of the ionic aggregates. The correlation between X-ray scattering results and the real space imaging for morphology of these zwitterionic copolymers will be presented.

  17. Aggregated Gas Molecules: Toxic to Protein?

    PubMed Central

    Zhang, Meng; Zuo, Guanghong; Chen, Jixiu; Gao, Yi; Fang, Haiping

    2013-01-01

    The biological toxicity of high levels of breathing gases has been known for centuries, but the mechanism remains elusive. Earlier work mainly focused on the influences of dispersed gas molecules dissolved in water on biomolecules. However, recent studies confirmed the existence of aggregated gas molecules at the water-solid interface. In this paper, we have investigated the binding preference of aggregated gas molecules on proteins with molecular dynamics simulations, using nitrogen (N2) gas and the Src-homology 3 (SH3) domain as the model system. Aggregated N2 molecules were strongly bound by the active sites of the SH3 domain, which could impair the activity of the protein. In contrast, dispersed N2 molecules did not specifically interact with the SH3 domain. These observations extend our understanding of the possible toxicity of aggregates of gas molecules in the function of proteins. PMID:23588597

  18. GPP Webinar: The Power of Aggregated Purchasing

    EPA Pesticide Factsheets

    Green Power Partnership webinar examining the use of an aggregated model for renewable energy purchases which can lead to significant energy, environmental and financial benefits by addressing administrative cost barriers and leveraging the shared purchasi

  19. Familial Aggregation and Childhood Blood Pressure

    PubMed Central

    Xu, Xiaojing; Su, Shaoyong; Snieder, Harold

    2015-01-01

    There is growing concern about elevated blood pressure (BP) in children. The evidence for familial aggregation of childhood BP is substantial. Twin studies have shown that a large part of the familial aggregation of childhood BP is due to genes. The first part of this review provides the latest progress in gene finding for childhood BP, focusing on the combined effects of multiple loci identified from the genome-wide association studies on adult BP. We further review the evidence on the contribution of the genetic components of other family risk factors to the familial aggregation of childhood BP including obesity, birth weight, sleep quality, sodium intake, parental smoking, and socioeconomic status. At the end, we emphasize the promise of using genomic-relatedness-matrix restricted maximum likelihood (GREML) analysis, a method that uses genome-wide data from unrelated individuals, in answering a number of unsolved questions in the familial aggregation of childhood BP. PMID:25432901

  20. Acid soluble, pepsin resistant platelet aggregating material

    SciTech Connect

    Schneider, M.D.

    1982-08-31

    Disclosed is an acid soluble, pepsin resistant, platelet aggregating material isolated from equine arterial tissue by extraction with dilute aqueous acid. The method of isolation and use to control bleeding are described. 4 figs.