AUX: a scripting language for auditory signal processing and software packages for psychoacoustic experiments and education.

PubMed

Kwon, Bomjun J

2012-06-01

This article introduces AUX (AUditory syntaX), a scripting syntax specifically designed to describe auditory signals and processing, to the members of the behavioral research community. The syntax is based on descriptive function names and intuitive operators suitable for researchers and students without substantial training in programming, who wish to generate and examine sound signals using a written script. In this article, the essence of AUX is discussed and practical examples of AUX scripts specifying various signals are illustrated. Additionally, two accompanying Windows-based programs and development libraries are described. AUX Viewer is a program that generates, visualizes, and plays sounds specified in AUX. AUX Viewer can also be used for class demonstrations or presentations. Another program, Psycon, allows a wide range of sound signals to be used as stimuli in common psychophysical testing paradigms, such as the adaptive procedure, the method of constant stimuli, and the method of adjustment. AUX Library is also provided, so that researchers can develop their own programs utilizing AUX. The philosophical basis of AUX is to separate signal generation from the user interface needed for experiments. AUX scripts are portable and reusable; they can be shared by other researchers, regardless of differences in actual AUX-based programs, and reused for future experiments. In short, the use of AUX can be potentially beneficial to all members of the research community-both those with programming backgrounds and those without.

The acoustic communities: Definition, description and ecological role.

PubMed

Farina, Almo; James, Philip

2016-09-01

An acoustic community is defined as an aggregation of species that produces sound by using internal or extra-body sound-producing tools. Such communities occur in aquatic (freshwater and marine) and terrestrial environments. An acoustic community is the biophonic component of a soundtope and is characterized by its acoustic signature, which results from the distribution of sonic information associated with signal amplitude and frequency. Distinct acoustic communities can be described according to habitat, the frequency range of the acoustic signals, and the time of day or the season. Near and far fields can be identified empirically, thus the acoustic community can be used as a proxy for biodiversity richness. The importance of ecoacoustic research is rapidly growing due to the increasing awareness of the intrusion of anthropogenic sounds (technophonies) into natural and human-modified ecosystems and the urgent need to adopt more efficient predictive tools to compensate for the effects of climate change. The concept of an acoustic community provides an operational scale for a non-intrusive biodiversity survey and analysis that can be carried out using new passive audio recording technology, coupled with methods of vast data processing and storage. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Models and signal processing for an implanted ethanol bio-sensor.

PubMed

Han, Jae-Joon; Doerschuk, Peter C; Gelfand, Saul B; O'Connor, Sean J

2008-02-01

The understanding of drinking patterns leading to alcoholism has been hindered by an inability to unobtrusively measure ethanol consumption over periods of weeks to months in the community environment. An implantable ethanol sensor is under development using microelectromechanical systems technology. For safety and user acceptability issues, the sensor will be implanted subcutaneously and, therefore, measure peripheral-tissue ethanol concentration. Determining ethanol consumption and kinetics in other compartments from the time course of peripheral-tissue ethanol concentration requires sophisticated signal processing based on detailed descriptions of the relevant physiology. A statistical signal processing system based on detailed models of the physiology and using extended Kalman filtering and dynamic programming tools is described which can estimate the time series of ethanol concentration in blood, liver, and peripheral tissue and the time series of ethanol consumption based on peripheral-tissue ethanol concentration measurements.

Body size distributions signal a regime shift in a lake ecosystem

USGS Publications Warehouse

Spanbauer, Trisha; Allen, Craig R.; Angeler, David G.; Eason, Tarsha; Fritz, Sherilyn C.; Garmestani, Ahjond S.; Nash, Kirsty L.; Stone, Jeffery R.; Stow, Craig A.; Sundstrom, Shana M.

2016-01-01

Communities of organisms, from mammals to microorganisms, have discontinuous distributions of body size. This pattern of size structuring is a conservative trait of community organization and is a product of processes that occur at multiple spatial and temporal scales. In this study, we assessed whether body size patterns serve as an indicator of a threshold between alternative regimes. Over the past 7000 years, the biological communities of Foy Lake (Montana, USA) have undergone a major regime shift owing to climate change. We used a palaeoecological record of diatom communities to estimate diatom sizes, and then analysed the discontinuous distribution of organism sizes over time. We used Bayesian classification and regression tree models to determine that all time intervals exhibited aggregations of sizes separated by gaps in the distribution and found a significant change in diatom body size distributions approximately 150 years before the identified ecosystem regime shift. We suggest that discontinuity analysis is a useful addition to the suite of tools for the detection of early warning signals of regime shifts.

Label-free molecular imaging of bacterial communities of the opportunistic pathogen Pseudomonas aeruginosa

NASA Astrophysics Data System (ADS)

Baig, Nameera; Polisetti, Sneha; Morales-Soto, Nydia; Dunham, Sage J. B.; Sweedler, Jonathan V.; Shrout, Joshua D.; Bohn, Paul W.

2016-09-01

Biofilms, such as those formed by the opportunistic human pathogen Pseudomonas aeruginosa are complex, matrix enclosed, and surface-associated communities of cells. Bacteria that are part of a biofilm community are much more resistant to antibiotics and the host immune response than their free-floating counterparts. P. aeruginosa biofilms are associated with persistent and chronic infections in diseases such as cystic fibrosis and HIV-AIDS. P. aeruginosa synthesizes and secretes signaling molecules such as the Pseudomonas quinolone signal (PQS) which are implicated in quorum sensing (QS), where bacteria regulate gene expression based on population density. Processes such as biofilms formation and virulence are regulated by QS. This manuscript describes the powerful molecular imaging capabilities of confocal Raman microscopy (CRM) and surface enhanced Raman spectroscopy (SERS) in conjunction with multivariate statistical tools such as principal component analysis (PCA) for studying the spatiotemporal distribution of signaling molecules, secondary metabolites and virulence factors in biofilm communities of P. aeruginosa. Our observations reveal that the laboratory strain PAO1C synthesizes and secretes 2-alkyl-4-hydroxyquinoline N-oxides and 2-alkyl-4-hydroxyquinolones in high abundance, while the isogenic acyl homoserine lactone QS-deficient mutant (ΔlasIΔrhlI) strain produces predominantly 2-alkyl-quinolones during biofilm formation. This study underscores the use of CRM, along with traditional biological tools such as genetics, for studying the behavior of microbial communities at the molecular level.

Naval sensor data database (NSDD)

NASA Astrophysics Data System (ADS)

Robertson, Candace J.; Tubridy, Lisa H.

1999-08-01

The Naval Sensor Data database (NSDD) is a multi-year effort to archive, catalogue, and disseminate data from all types of sensors to the mine warfare, signal and image processing, and sensor development communities. The purpose is to improve and accelerate research and technology. Providing performers with the data required to develop and validate improvements in hardware, simulation, and processing will foster advances in sensor and system performance. The NSDD will provide a centralized source of sensor data in its associated ground truth, which will support an improved understanding will be benefited in the areas of signal processing, computer-aided detection and classification, data compression, data fusion, and geo-referencing, as well as sensor and sensor system design.

Identification of Habitat-Specific Biomes of Aquatic Fungal Communities Using a Comprehensive Nearly Full-Length 18S rRNA Dataset Enriched with Contextual Data

PubMed Central

Panzer, Katrin; Yilmaz, Pelin; Weiß, Michael; Reich, Lothar; Richter, Michael; Wiese, Jutta; Schmaljohann, Rolf; Labes, Antje; Imhoff, Johannes F.; Glöckner, Frank Oliver; Reich, Marlis

2015-01-01

Molecular diversity surveys have demonstrated that aquatic fungi are highly diverse, and that they play fundamental ecological roles in aquatic systems. Unfortunately, comparative studies of aquatic fungal communities are few and far between, due to the scarcity of adequate datasets. We combined all publicly available fungal 18S ribosomal RNA (rRNA) gene sequences with new sequence data from a marine fungi culture collection. We further enriched this dataset by adding validated contextual data. Specifically, we included data on the habitat type of the samples assigning fungal taxa to ten different habitat categories. This dataset has been created with the intention to serve as a valuable reference dataset for aquatic fungi including a phylogenetic reference tree. The combined data enabled us to infer fungal community patterns in aquatic systems. Pairwise habitat comparisons showed significant phylogenetic differences, indicating that habitat strongly affects fungal community structure. Fungal taxonomic composition differed considerably even on phylum and class level. Freshwater fungal assemblage was most different from all other habitat types and was dominated by basal fungal lineages. For most communities, phylogenetic signals indicated clustering of sequences suggesting that environmental factors were the main drivers of fungal community structure, rather than species competition. Thus, the diversification process of aquatic fungi must be highly clade specific in some cases.The combined data enabled us to infer fungal community patterns in aquatic systems. Pairwise habitat comparisons showed significant phylogenetic differences, indicating that habitat strongly affects fungal community structure. Fungal taxonomic composition differed considerably even on phylum and class level. Freshwater fungal assemblage was most different from all other habitat types and was dominated by basal fungal lineages. For most communities, phylogenetic signals indicated clustering of sequences suggesting that environmental factors were the main drivers of fungal community structure, rather than species competition. Thus, the diversification process of aquatic fungi must be highly clade specific in some cases. PMID:26226014

SERS as a tool for in vitro toxicology.

PubMed

Fisher, Kate M; McLeish, Jennifer A; Jamieson, Lauren E; Jiang, Jing; Hopgood, James R; McLaughlin, Stephen; Donaldson, Ken; Campbell, Colin J

2016-06-23

Measuring markers of stress such as pH and redox potential are important when studying toxicology in in vitro models because they are markers of oxidative stress, apoptosis and viability. While surface enhanced Raman spectroscopy is ideally suited to the measurement of redox potential and pH in live cells, the time-intensive nature and perceived difficulty in signal analysis and interpretation can be a barrier to its broad uptake by the biological community. In this paper we detail the development of signal processing and analysis algorithms that allow SERS spectra to be automatically processed so that the output of the processing is a pH or redox potential value. By automating signal processing we were able to carry out a comparative evaluation of the toxicology of silver and zinc oxide nanoparticles and correlate our findings with qPCR analysis. The combination of these two analytical techniques sheds light on the differences in toxicology between these two materials from the perspective of oxidative stress.

Bacterial signaling ecology and potential applications during aquatic biofilm construction.

PubMed

Vega, Leticia M; Alvarez, Pedro J; McLean, Robert J C

2014-07-01

In their natural environment, bacteria and other microorganisms typically grow as surface-adherent biofilm communities. Cell signal processes, including quorum signaling, are now recognized as being intimately involved in the development and function of biofilms. In contrast to their planktonic (unattached) counterparts, bacteria within biofilms are notoriously resistant to many traditional antimicrobial agents and so represent a major challenge in industry and medicine. Although biofilms impact many human activities, they actually represent an ancient mode of bacterial growth as shown in the fossil record. Consequently, many aquatic organisms have evolved strategies involving signal manipulation to control or co-exist with biofilms. Here, we review the chemical ecology of biofilms and propose mechanisms whereby signal manipulation can be used to promote or control biofilms.

A labview-based GUI for the measurement of otoacoustic emissions.

PubMed

Wu, Ye; McNamara, D M; Ziarani, A K

2006-01-01

This paper presents the outcome of a software development project aimed at creating a stand-alone user-friendly signal processing algorithm for the estimation of distortion product otoacoustic emission (OAE) signals. OAE testing is one of the most commonly used methods of first screening of newborns' hearing. Most of the currently available commercial devices rely upon averaging long strings of data and subsequent discrete Fourier analysis to estimate low level OAE signals from within the background noise in the presence of the strong stimuli. The main shortcoming of the presently employed technology is the need for long measurement time and its low noise immunity. The result of the software development project presented here is a graphical user interface (GUI) module that implements a recently introduced adaptive technique of OAE signal estimation. This software module is easy to use and is freely disseminated on the Internet for the use of the hearing research community. This GUI module allows loading of the a priori recorded OAE signals into the workspace, and provides the user with interactive instructions for the OAE signal estimation. Moreover, the user can generate simulated OAE signals to objectively evaluate the performance capability of the implemented signal processing technique.

Generative Adversarial Networks: An Overview

NASA Astrophysics Data System (ADS)

Creswell, Antonia; White, Tom; Dumoulin, Vincent; Arulkumaran, Kai; Sengupta, Biswa; Bharath, Anil A.

2018-01-01

Generative adversarial networks (GANs) provide a way to learn deep representations without extensively annotated training data. They achieve this through deriving backpropagation signals through a competitive process involving a pair of networks. The representations that can be learned by GANs may be used in a variety of applications, including image synthesis, semantic image editing, style transfer, image super-resolution and classification. The aim of this review paper is to provide an overview of GANs for the signal processing community, drawing on familiar analogies and concepts where possible. In addition to identifying different methods for training and constructing GANs, we also point to remaining challenges in their theory and application.

Detection and inhibition of bacterial cell-cell communication.

PubMed

Rice, Scott A; McDougald, Diane; Givskov, Michael; Kjelleberg, Staffan

2008-01-01

Bacteria communicate with other members of their community through the secretion and perception of small chemical cues or signals. The recognition of a signal normally leads to the expression of a large suite of genes, which in some bacteria are involved in the regulation of virulence factors, and as a result, these signaling compounds are key regulatory factors in many disease processes. Thus, it is of interest when studying pathogens to understand the mechanisms used to control the expression of virulence genes so that strategies might be devised for the control of those pathogens. Clearly, the ability to interfere with this process of signaling represents a novel approach for the treatment of bacterial infections. There is a broad range of compounds that bacteria can use for signaling purposes, including fatty acids, peptides, N-acylated homoserine lactones, and the signals collectively called autoinducer 2 (AI-2). This chapter will focus on the latter two signaling systems as they are present in a range of medically relevant bacteria, and here we describe assays for determining whether an organism produces a particular signal and assays that can be used to identify inhibitors of the signaling cascade. Lastly, the signal detection and inhibition assays will be directly linked to the expression of virulence factors of specific pathogens.

The pathogenic persona of community associated oral streptococci

PubMed Central

Whitmore, Sarah E.; Lamont, Richard J.

2011-01-01

Summary The mitis group streptococci (MGS) are widespread in the oral cavity and are traditionally associated with oral health. However, these organisms have many attributes that contribute to the development of pathogenic oral communities. MGS adhere rapidly to saliva-coated tooth surfaces, thereby providing an attachment substratum for more overtly pathogenic organisms such as Porphyromonas gingivalis, and the two species assemble into heterotypic communities. Close physical association facilitates physiologic support, and pathogens such as Actinobacillus actinomycetemcomitans display resource partitioning to favour carbon sources generated by streptococcal metabolism. MGS exchange information with community members through a number of interspecies signaling systems including AI-2 and contact dependent mechanisms. Signal transduction systems induced in P. gingivalis are based on protein dephosphorylation mediated by the tyrosine phosphatase Ltp1, and converge on a LuxR-family transcriptional regulator, CdhR. Phenotypic responses in P. gingivalis include regulation of hemin uptake systems and gingipain activity, processes that are intimately linked to the virulence of the organism. Furthermore, communities of S. gordonii with P. gingivalis or with A. actinomycetemcomitans are more pathogenic in animal models than the constituent species alone. We propose that MGS should be considered accessory pathogens, organisms whose pathogenic potential only becomes evident in the context of a heterotypic microbial community. PMID:21635580

The pathogenic persona of community-associated oral streptococci.

PubMed

Whitmore, Sarah E; Lamont, Richard J

2011-07-01

The mitis group streptococci (MGS) are widespread in the oral cavity and are traditionally associated with oral health. However, these organisms have many attributes that contribute to the development of pathogenic oral communities. MGS adhere rapidly to saliva-coated tooth surfaces, thereby providing an attachment substratum for more overtly pathogenic organisms such as Porphyromonas gingivalis, and the two species assemble into heterotypic communities. Close physical association facilitates physiologic support, and pathogens such as Aggregatibacter actinomycetemcomitans display resource partitioning to favour carbon sources generated by streptococcal metabolism. MGS exchange information with community members through a number of interspecies signalling systems including AI-2 and contact dependent mechanisms. Signal transduction systems induced in P. gingivalis are based on protein dephosphorylation mediated by the tyrosine phosphatase Ltp1, and converge on a LuxR-family transcriptional regulator, CdhR. Phenotypic responses in P. gingivalis include regulation of hemin uptake systems and gingipain activity, processes that are intimately linked to the virulence of the organism. Furthermore, communities of S. gordonii with P. gingivalis or with A. actinomycetemcomitans are more pathogenic in animal models than the constituent species alone. We propose that MGS should be considered accessory pathogens, organisms whose pathogenic potential only becomes evident in the context of a heterotypic microbial community. © 2011 Blackwell Publishing Ltd.

A Vision for MSSP

NASA Astrophysics Data System (ADS)

Mottershead, John E.

2015-05-01

MSSP is our journal. It developed out of the research community and in that sense is owned by us, its readers and authors. It was started by a small group, all international leaders in System Identification, Measurement and Signal Processing, Modal Analysis, Machine and Structural Diagnostics etc., several of whom still provide invaluable advice and guidance through their work on the Editorial Board. Most importantly, Simon's leadership for almost three decades has been inspirational, dedicated and energetic. So, it is a great honour for me to have been invited to assume the editorial leadership of MSSP and continue the work of serving a new generation of researchers in the broad and evolving field of Mechanical Systems and Signal Processing.

A comprehensive map of the mTOR signaling network

PubMed Central

Caron, Etienne; Ghosh, Samik; Matsuoka, Yukiko; Ashton-Beaucage, Dariel; Therrien, Marc; Lemieux, Sébastien; Perreault, Claude; Roux, Philippe P; Kitano, Hiroaki

2010-01-01

The mammalian target of rapamycin (mTOR) is a central regulator of cell growth and proliferation. mTOR signaling is frequently dysregulated in oncogenic cells, and thus an attractive target for anticancer therapy. Using CellDesigner, a modeling support software for graphical notation, we present herein a comprehensive map of the mTOR signaling network, which includes 964 species connected by 777 reactions. The map complies with both the systems biology markup language (SBML) and graphical notation (SBGN) for computational analysis and graphical representation, respectively. As captured in the mTOR map, we review and discuss our current understanding of the mTOR signaling network and highlight the impact of mTOR feedback and crosstalk regulations on drug-based cancer therapy. This map is available on the Payao platform, a Web 2.0 based community-wide interactive process for creating more accurate and information-rich databases. Thus, this comprehensive map of the mTOR network will serve as a tool to facilitate systems-level study of up-to-date mTOR network components and signaling events toward the discovery of novel regulatory processes and therapeutic strategies for cancer. PMID:21179025

Pattern recognition of native plant communities: Manitou Colorado test site

NASA Technical Reports Server (NTRS)

Driscoll, R. S.

1972-01-01

Optimum channel selection among 12 channels of multispectral scanner imagery identified six as providing the best information about 11 vegetation classes and two nonvegetation classes at the Manitou Experimental Forest. Intensive preprocessing of the scanner signals was required to eliminate a serious scan angle effect. Final processing of the normalized data provided acceptable recognition results of generalized plant community types. Serious errors occurred with attempts to classify specific community types within upland grassland areas. The consideration of the convex mixtures concept (effects of amounts of live plant cover, exposed soil, and plant litter cover on apparent scene radiances) significantly improved the classification of some of the grassland classes.

FUNCTIONAL NETWORK ARCHITECTURE OF READING-RELATED REGIONS ACROSS DEVELOPMENT

PubMed Central

Vogel, Alecia C.; Church, Jessica A.; Power, Jonathan D.; Miezin, Fran M.; Petersen, Steven E.; Schlaggar, Bradley L.

2013-01-01

Reading requires coordinated neural processing across a large number of brain regions. Studying relationships between reading-related regions informs the specificity of information processing performed in each region. Here, regions of interest were defined from a meta-analysis of reading studies, including a developmental study. Relationships between regions were defined as temporal correlations in spontaneous fMRI signal; i.e., resting state functional connectivity MRI (RSFC). Graph theory based network analysis defined the community structure of the “reading-related” regions. Regions sorted into previously defined communities, such as the fronto-parietal and cingulo-opercular control networks, and the default mode network. This structure was similar in children, and no apparent “reading” community was defined in any age group. These results argue against regions, or sets of regions, being specific or preferential for reading, instead indicating that regions used in reading are also used in a number of other tasks. PMID:23506969

Partitioning the impact of environment and spatial structure on alpha and beta components of taxonomic, functional, and phylogenetic diversity in European ants.

PubMed

Arnan, Xavier; Cerdá, Xim; Retana, Javier

2015-01-01

We analyze the relative contribution of environmental and spatial variables to the alpha and beta components of taxonomic (TD), phylogenetic (PD), and functional (FD) diversity in ant communities found along different climate and anthropogenic disturbance gradients across western and central Europe, in order to assess the mechanisms structuring ant biodiversity. To this aim we calculated alpha and beta TD, PD, and FD for 349 ant communities, which included a total of 155 ant species; we examined 10 functional traits and phylogenetic relatedness. Variation partitioning was used to examine how much variation in ant diversity was explained by environmental and spatial variables. Autocorrelation in diversity measures and each trait's phylogenetic signal were also analyzed. We found strong autocorrelation in diversity measures. Both environmental and spatial variables significantly contributed to variation in TD, PD, and FD at both alpha and beta scales; spatial structure had the larger influence. The different facets of diversity showed similar patterns along environmental gradients. Environment explained a much larger percentage of variation in FD than in TD or PD. All traits demonstrated strong phylogenetic signals. Our results indicate that environmental filtering and dispersal limitations structure all types of diversity in ant communities. Strong dispersal limitations appear to have led to clustering of TD, PD, and FD in western and central Europe, probably because different historical and evolutionary processes generated different pools of species. Remarkably, these three facets of diversity showed parallel patterns along environmental gradients. Trait-mediated species sorting and niche conservatism appear to structure ant diversity, as evidenced by the fact that more variation was explained for FD and that all traits had strong phylogenetic signals. Since environmental variables explained much more variation in FD than in PD, functional diversity should be a better indicator of community assembly processes than phylogenetic diversity.

Evaluating Acoustic Emission Signals as an in situ process monitoring technique for Selective Laser Melting (SLM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, Karl A.; Candy, Jim V.; Guss, Gabe

2016-10-14

In situ real-time monitoring of the Selective Laser Melting (SLM) process has significant implications for the AM community. The ability to adjust the SLM process parameters during a build (in real-time) can save time, money and eliminate expensive material waste. Having a feedback loop in the process would allow the system to potentially ‘fix’ problem regions before a next powder layer is added. In this study we have investigated acoustic emission (AE) phenomena generated during the SLM process, and evaluated the results in terms of a single process parameter, of an in situ process monitoring technique.

Bioactive Molecules in Soil Ecosystems: Masters of the Underground

PubMed Central

Zhuang, Xuliang; Gao, Jie; Ma, Anzhou; Fu, Shenglei; Zhuang, Guoqiang

2013-01-01

Complex biological and ecological processes occur in the rhizosphere through ecosystem-level interactions between roots, microorganisms and soil fauna. Over the past decade, studies of the rhizosphere have revealed that when roots, microorganisms and soil fauna physically contact one another, bioactive molecular exchanges often mediate these interactions as intercellular signal, which prepare the partners for successful interactions. Despite the importance of bioactive molecules in sustainable agriculture, little is known of their numerous functions, and improving plant health and productivity by altering ecological processes remains difficult. In this review, we describe the major bioactive molecules present in below-ground ecosystems (i.e., flavonoids, exopolysaccharides, antibiotics and quorum-sensing signals), and we discuss how these molecules affect microbial communities, nutrient availability and plant defense responses. PMID:23615474

Setting the standards for signal transduction research.

PubMed

Saez-Rodriguez, Julio; Alexopoulos, Leonidas G; Stolovitzky, Gustavo

2011-02-15

Major advances in high-throughput technology platforms, coupled with increasingly sophisticated computational methods for systematic data analysis, have provided scientists with tools to better understand the complexity of signaling networks. In this era of massive and diverse data collection, standardization efforts that streamline data gathering, analysis, storage, and sharing are becoming a necessity. Here, we give an overview of current technologies to study signal transduction. We argue that along with the opportunities the new technologies open, their heterogeneous nature poses critical challenges for data handling that are further increased when data are to be integrated in mathematical models. Efficient standardization through markup languages and data annotation is a sine qua non condition for a systems-level analysis of signaling processes. It remains to be seen the extent to which and the speed at which the emerging standardization efforts will be embraced by the signaling community.

Signaling in host-associated microbial communities

PubMed Central

Fischbach, Michael A.; Segre, Julia A.

2016-01-01

Human-associated microbiota form and stabilize communities based on interspecies interactions. We review how these microbe-microbe and microbe-host interactions are communicated to shape communities over a human’s lifespan, including periods of health and disease. Modeling and dissecting signaling in host-associated communities is crucial to understand their function, and will open the door to therapies that prevent or correct microbial community dysfunction to promote health and treat disease. PMID:26967294

(Re)politicising and (re)positioning prevention: community mobilisations and AIDS prevention in the new AIDS era.

PubMed

Rolston, Imara Ajani

2016-07-01

An increasing focus on the relationship between AIDS prevalence and socio-economic inequality signals the need for a revaluation of the role of "politics" and "power" in AIDS prevention. This revaluation bears great significance when considering the future trajectories of the AIDS prevention efforts that target highly marginalised populations with high prevalence rates. An emphasis on intersecting forms of inequality has direct implications for the future of AIDS prevention practice. This study explores the experiences of participants, facilitators and local stakeholders applying the United Nations Development Programme (UNDP) Community Capacity Enhancement-Community Conversations (CCE-CC) approach to AIDS prevention in the Eastern Cape province of South Africa. It uses the political narrative analysis of life histories and semi-structured interviews as a means to interrogate the lived experiences of local actors participating in or influenced by this popularised form of community mobilisation used throughout sub-Saharan Africa. Findings suggest the need for a more explicit and intentional valuation for the intersection between the social and political determinants of health in programmes that use community mobilisation as prevention. They also signal a need to critically re-evaluate "community mobilisation" as an AIDS prevention tradition. Intersecting social and political power dynamics play a significant role in both opening up and constraining community mobilisation efforts. This paper proposes the need for a pedagogical turn to "deep organising" and "participatory forms of democracy", as a necessary frontier for programmes working with highly marginalised populations with high prevalence rates. Programmes need to more explicitly support, protect, and advocate for the ability of affected communities to engage in political processes, discourse and long-term organising.

EARLINET Single Calculus Chain - technical - Part 1: Pre-processing of raw lidar data

NASA Astrophysics Data System (ADS)

D'Amico, Giuseppe; Amodeo, Aldo; Mattis, Ina; Freudenthaler, Volker; Pappalardo, Gelsomina

2016-02-01

In this paper we describe an automatic tool for the pre-processing of aerosol lidar data called ELPP (EARLINET Lidar Pre-Processor). It is one of two calculus modules of the EARLINET Single Calculus Chain (SCC), the automatic tool for the analysis of EARLINET data. ELPP is an open source module that executes instrumental corrections and data handling of the raw lidar signals, making the lidar data ready to be processed by the optical retrieval algorithms. According to the specific lidar configuration, ELPP automatically performs dead-time correction, atmospheric and electronic background subtraction, gluing of lidar signals, and trigger-delay correction. Moreover, the signal-to-noise ratio of the pre-processed signals can be improved by means of configurable time integration of the raw signals and/or spatial smoothing. ELPP delivers the statistical uncertainties of the final products by means of error propagation or Monte Carlo simulations. During the development of ELPP, particular attention has been payed to make the tool flexible enough to handle all lidar configurations currently used within the EARLINET community. Moreover, it has been designed in a modular way to allow an easy extension to lidar configurations not yet implemented. The primary goal of ELPP is to enable the application of quality-assured procedures in the lidar data analysis starting from the raw lidar data. This provides the added value of full traceability of each delivered lidar product. Several tests have been performed to check the proper functioning of ELPP. The whole SCC has been tested with the same synthetic data sets, which were used for the EARLINET algorithm inter-comparison exercise. ELPP has been successfully employed for the automatic near-real-time pre-processing of the raw lidar data measured during several EARLINET inter-comparison campaigns as well as during intense field campaigns.

Image motion environments: background noise for movement-based animal signals.

PubMed

Peters, Richard; Hemmi, Jan; Zeil, Jochen

2008-05-01

Understanding the evolution of animal signals has to include consideration of the structure of signal and noise, and the sensory mechanisms that detect the signals. Considerable progress has been made in understanding sounds and colour signals, however, the degree to which movement-based signals are constrained by the particular patterns of environmental image motion is poorly understood. Here we have quantified the image motion generated by wind-blown plants at 12 sites in the coastal habitat of the Australian lizard Amphibolurus muricatus. Sampling across different plant communities and meteorological conditions revealed distinct image motion environments. At all locations, image motion became more directional and apparent speed increased as wind speeds increased. The magnitude of these changes and the spatial distribution of image motion, however, varied between locations probably as a function of plant structure and the topographic location. In addition, we show that the background motion noise depends strongly on the particular depth-structure of the environment and argue that such micro-habitat differences suggest specific strategies to preserve signal efficacy. Movement-based signals and motion processing mechanisms, therefore, may reveal the same type of habitat specific structural variation that we see for signals from other modalities.

Character displacement of Cercopithecini primate visual signals

PubMed Central

Allen, William L.; Stevens, Martin; Higham, James P.

2014-01-01

Animal visual signals have the potential to act as an isolating barrier to prevent interbreeding of populations through a role in species recognition. Within communities of competing species, species recognition signals are predicted to undergo character displacement, becoming more visually distinctive from each other, however this pattern has rarely been identified. Using computational face recognition algorithms to model primate face processing, we demonstrate that the face patterns of guenons (tribe: Cercopithecini) have evolved under selection to become more visually distinctive from those of other guenon species with whom they are sympatric. The relationship between the appearances of sympatric species suggests that distinguishing conspecifics from other guenon species has been a major driver of diversification in guenon face appearance. Visual signals that have undergone character displacement may have had an important role in the tribe’s radiation, keeping populations that became geographically separated reproductively isolated on secondary contact. PMID:24967517

Community-Based Participatory Research Integrates Behavioral and Biological Research to Achieve Health Equity for Native Hawaiians.

PubMed

Townsend, Claire K M; Dillard, Adrienne; Hosoda, Kelsea K; Maskarinec, Gregory G; Maunakea, Alika K; Yoshimura, Sheryl R; Hughes, Claire; Palakiko, Donna-Marie; Kehauoha, Bridget Puni; Kaholokula, Joseph Keawe'aimoku

2015-12-22

Native Hawaiians bear a disproportionate burden of type-2 diabetes and related complications compared to all other groups in Hawai'i (e.g., Whites, Japanese, Korean). Distrust in these communities is a significant barrier to participation in epigenetic research studies seeking to better understand disease processes. The purpose of this paper is to describe the community-based participatory research (CBPR) approach and research process we employed to integrate behavior and biological sciences with community health priorities. A CBPR approach was used to test a 3-month evidence-based, diabetes self-management intervention (N = 65). To investigate the molecular mechanisms linking inflammation with glucose homeostasis, a subset of participants (n = 16) provided peripheral blood mononuclear cells. Community and academic researchers collaborated on research design, assessment protocols, and participant recruitment, prioritizing participants' convenience and education and strictly limiting the use of the data collected. Preliminary results indicate significant changes in DNA methylation at gene regions associated with inflammation and diabetes signaling pathways and significant improvements in hemoglobin A1c, self-care activities, and diabetes distress and understanding. This study integrates community, behavioral, and epigenomic expertise to better understand the outcomes of a diabetes self-management intervention. Key lessons learned suggest the studies requiring biospecimen collection in indigenous populations require community trust of the researchers, mutual benefits for the community and researchers, and for the researchers to prioritize the community's needs. CBPR may be an important tool in providing communities the voice and protections to participate in studies requiring biospecimens.

Emergency preparedness: community-based short-term eruption forecasting at Campi Flegrei

NASA Astrophysics Data System (ADS)

Selva, Jacopo; Marzocchi, Warner; Civetta, Lucia; Del Pezzo, Edoardo; Papale, Paolo

2010-05-01

A key element in emergency preparedness is to define advance tools to assist decision makers and emergency management groups during crises. Such tools must be prepared in advance, accounting for all of expertise and scientific knowledge accumulated through time. During a pre-eruptive phase, the key for sound short-term eruption forecasting is the analysis of the monitoring signals. This involves the capability (i) to recognize anomalous signals and to relate single or combined anomalies to physical processes, assigning them probability values, and (ii) to quickly provide an answer to the observed phenomena even when unexpected. Here we present a > 4 years long process devoted to define the pre-eruptive Event Tree (ET) for Campi Flegrei. A community of about 40 experts in volcanology and volcano monitoring participating to two Italian Projects on Campi Flegrei funded by the Italian Civil Protection, has been constituted and trained during periodic meetings on the statistical methods and the model BET_EF (Marzocchi et al., 2008) that forms the statistical package tool for ET definition. Model calibration has been carried out through public elicitation sessions, preceded and followed by devoted meetings and web forum discussion on the monitoring parameters, their accuracy and relevance, and their potential meanings. The calibrated ET allows anomalies in the monitored parameters to be recognized and interpreted, assigning probability values to each set of data. This process de-personalizes the difficult task of interpreting multi-parametric sets of data during on-going emergencies, and provides a view of the observed variations that accounts for the averaged, weighted opinion of the scientific community. An additional positive outcome of the described ET calibration process is that of providing a picture of the degree of confidence by the expert community on the capability of the many different monitored quantities of recognizing significant variations in the state of the volcano. This picture is particularly useful since it can be used to guide future implementations in the monitoring network, as well as research investments aimed at substantially improving the capability to forecast the short-term volcanic hazard.

SPIKE – a database, visualization and analysis tool of cellular signaling pathways

PubMed Central

Elkon, Ran; Vesterman, Rita; Amit, Nira; Ulitsky, Igor; Zohar, Idan; Weisz, Mali; Mass, Gilad; Orlev, Nir; Sternberg, Giora; Blekhman, Ran; Assa, Jackie; Shiloh, Yosef; Shamir, Ron

2008-01-01

Background Biological signaling pathways that govern cellular physiology form an intricate web of tightly regulated interlocking processes. Data on these regulatory networks are accumulating at an unprecedented pace. The assimilation, visualization and interpretation of these data have become a major challenge in biological research, and once met, will greatly boost our ability to understand cell functioning on a systems level. Results To cope with this challenge, we are developing the SPIKE knowledge-base of signaling pathways. SPIKE contains three main software components: 1) A database (DB) of biological signaling pathways. Carefully curated information from the literature and data from large public sources constitute distinct tiers of the DB. 2) A visualization package that allows interactive graphic representations of regulatory interactions stored in the DB and superposition of functional genomic and proteomic data on the maps. 3) An algorithmic inference engine that analyzes the networks for novel functional interplays between network components. SPIKE is designed and implemented as a community tool and therefore provides a user-friendly interface that allows registered users to upload data to SPIKE DB. Our vision is that the DB will be populated by a distributed and highly collaborative effort undertaken by multiple groups in the research community, where each group contributes data in its field of expertise. Conclusion The integrated capabilities of SPIKE make it a powerful platform for the analysis of signaling networks and the integration of knowledge on such networks with omics data. PMID:18289391

Species-independent attraction to biofilms through electrical signaling

PubMed Central

Humphries, Jacqueline; Xiong, Liyang; Liu, Jintao; Prindle, Arthur; Yuan, Fang; Arjes, Heidi A.; Tsimring, Lev; Süel, Gürol M.

2017-01-01

Summary Bacteria residing within biofilm communities can coordinate their behavior through cell-to-cell signaling. However, it remains unclear if these signals can also influence the behavior of distant cells that are not part of the community. Using a microfluidic approach, we find that potassium ion channel-mediated electrical signaling generated by a Bacillus subtilis biofilm can attract distant cells. Integration of experiments and mathematical modeling indicates that extracellular potassium emitted from the biofilm alters the membrane potential of distant cells, thereby directing their motility. This electrically-mediated attraction appears to be a generic mechanism that enables cross-species interactions, as Pseudomonas aeruginosa cells also become attracted to the electrical signal released by the B. subtilis biofilm. Cells within a biofilm community can thus not only coordinate their own behavior, but also influence the behavior of diverse bacteria at a distance through long-range electrical signaling. PMID:28086091

Bacterial Biofilms as Complex Communities

NASA Astrophysics Data System (ADS)

Vlamakis, Hera

2010-03-01

Many microbial populations form surface-associated multicellular communities known as biofilms. These multicellular communities are encased in a self-produced extracellular matrix composed of polysaccharides and proteins. Division of labor is a key feature of these communities and different cells serve distinct functions. We have found that in biofilms of the bacterium Bacillus subtilis, different cell types including matrix-producing and sporulating cells coexist and localize to distinct regions within the structured community. We were interested in understanding how these different cell types arise. Using fluorescence reporters under the control of promoters that are specific for distinct cell types we were able to follow the dynamics of differentiation throughout biofilm development. We found that a series of extracellular signals leads to differentiation of distinct cell types during biofilm formation. In addition, we found that extracellular matrix functions as a differentiation signal for timely sporulation within a biofilm and mutants unable to produce matrix were delayed in sporulation. Our results indicate that within a biofilm, cell-cell signaling is directional in that one cell type produces a signal that is sensed by another distinct cell type. Furthermore, once differentiated, cells become resistant to the action of other signaling molecules making it possible to maintain distinct cell populations over prolonged periods.

Modeling Geodetic Processes with Levy α-Stable Distribution and FARIMA

NASA Astrophysics Data System (ADS)

Montillet, Jean-Philippe; Yu, Kegen

2015-04-01

Over the last years the scientific community has been using the auto regressive moving average (ARMA) model in the modeling of the noise in global positioning system (GPS) time series (daily solution). This work starts with the investigation of the limit of the ARMA model which is widely used in signal processing when the measurement noise is white. Since a typical GPS time series consists of geophysical signals (e.g., seasonal signal) and stochastic processes (e.g., coloured and white noise), the ARMA model may be inappropriate. Therefore, the application of the fractional auto-regressive integrated moving average (FARIMA) model is investigated. The simulation results using simulated time series as well as real GPS time series from a few selected stations around Australia show that the FARIMA model fits the time series better than other models when the coloured noise is larger than the white noise. The second fold of this work focuses on fitting the GPS time series with the family of Levy α-stable distributions. Using this distribution, a hypothesis test is developed to eliminate effectively coarse outliers from GPS time series, achieving better performance than using the rule of thumb of n standard deviations (with n chosen empirically).

Microbial interactions: ecology in a molecular perspective.

PubMed

Braga, Raíssa Mesquita; Dourado, Manuella Nóbrega; Araújo, Welington Luiz

2016-12-01

The microorganism-microorganism or microorganism-host interactions are the key strategy to colonize and establish in a variety of different environments. These interactions involve all ecological aspects, including physiochemical changes, metabolite exchange, metabolite conversion, signaling, chemotaxis and genetic exchange resulting in genotype selection. In addition, the establishment in the environment depends on the species diversity, since high functional redundancy in the microbial community increases the competitive ability of the community, decreasing the possibility of an invader to establish in this environment. Therefore, these associations are the result of a co-evolution process that leads to the adaptation and specialization, allowing the occupation of different niches, by reducing biotic and abiotic stress or exchanging growth factors and signaling. Microbial interactions occur by the transference of molecular and genetic information, and many mechanisms can be involved in this exchange, such as secondary metabolites, siderophores, quorum sensing system, biofilm formation, and cellular transduction signaling, among others. The ultimate unit of interaction is the gene expression of each organism in response to an environmental (biotic or abiotic) stimulus, which is responsible for the production of molecules involved in these interactions. Therefore, in the present review, we focused on some molecular mechanisms involved in the microbial interaction, not only in microbial-host interaction, which has been exploited by other reviews, but also in the molecular strategy used by different microorganisms in the environment that can modulate the establishment and structuration of the microbial community. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Changes in the microbial communities during co-composting of digestates☆

PubMed Central

Franke-Whittle, Ingrid H.; Confalonieri, Alberto; Insam, Heribert; Schlegelmilch, Mirko; Körner, Ina

2014-01-01

Anaerobic digestion is a waste treatment method which is of increasing interest worldwide. At the end of the process, a digestate remains, which can gain added value by being composted. A study was conducted in order to investigate microbial community dynamics during the composting process of a mixture of anaerobic digestate (derived from the anaerobic digestion of municipal food waste), green wastes and a screened compost (green waste/kitchen waste compost), using the COMPOCHIP microarray. The composting process showed a typical temperature development, and the highest degradation rates occurred during the first 14 days of composting, as seen from the elevated CO2 content in the exhaust air. With an exception of elevated nitrite and nitrate levels in the day 34 samples, physical–chemical parameters for all compost samples collected during the 63 day process indicated typical composting conditions. The microbial communities changed over the 63 days of composting. According to principal component analysis of the COMPOCHIP microarray results, compost samples from the start of the experiment were found to cluster most closely with the digestate and screened compost samples. The green waste samples were found to group separately. All starting materials investigated were found to yield fewer and lower signals when compared to the samples collected during the composting experiment. PMID:24456768

A Comprehensive Review of Sensors and Instrumentation Methods in Devices for Musical Expression

PubMed Central

Medeiros, Carolina Brum; Wanderley, Marcelo M.

2014-01-01

Digital Musical Instruments (DMIs) are musical instruments typically composed of a control surface where user interaction is measured by sensors whose values are mapped to sound synthesis algorithms. These instruments have gained interest among skilled musicians and performers in the last decades leading to artistic practices including musical performance, interactive installations and dance. The creation of DMIs typically involves several areas, among them: arts, design and engineering. The balance between these areas is an essential task in DMI design so that the resulting instruments are aesthetically appealing, robust, and allow responsive, accurate and repeatable sensing. In this paper, we review the use of sensors in the DMI community as manifested in the proceedings of the International Conference on New Interfaces for Musical Expression (NIME 2009–2013). Focusing on the sensor technologies and signal conditioning techniques used by the NIME community. Although it has been claimed that specifications for artistic tools are harder than those for military applications, this study raises a paradox showing that in most of the cases, DMIs are based on a few basic sensors types and unsophisticated engineering solutions, not taking advantage of more advanced sensing, instrumentation and signal processing techniques that could dramatically improve their response. We aim to raise awareness of limitations of any engineering solution and to assert the benefits of advanced electronics instrumentation design in DMIs. For this, we propose the use of specialized sensors such as strain gages, advanced conditioning circuits and signal processing tools such as sensor fusion. We believe that careful electronic instrumentation design may lead to more responsive instruments. PMID:25068865

A comprehensive review of sensors and instrumentation methods in devices for musical expression.

PubMed

Medeiros, Carolina Brum; Wanderley, Marcelo M

2014-07-25

Digital Musical Instruments (DMIs) are musical instruments typically composed of a control surface where user interaction is measured by sensors whose values are mapped to sound synthesis algorithms. These instruments have gained interest among skilled musicians and performers in the last decades leading to artistic practices including musical performance, interactive installations and dance. The creation of DMIs typically involves several areas, among them: arts, design and engineering. The balance between these areas is an essential task in DMI design so that the resulting instruments are aesthetically appealing, robust, and allow responsive, accurate and repeatable sensing. In this paper, we review the use of sensors in the DMI community as manifested in the proceedings of the International Conference on New Interfaces for Musical Expression (NIME 2009-2013). Focusing on the sensor technologies and signal conditioning techniques used by the NIME community. Although it has been claimed that specifications for artistic tools are harder than those for military applications, this study raises a paradox showing that in most of the cases, DMIs are based on a few basic sensors types and unsophisticated engineering solutions, not taking advantage of more advanced sensing, instrumentation and signal processing techniques that could dramatically improve their response. We aim to raise awareness of limitations of any engineering solution and to assert the benefits of advanced electronics instrumentation design in DMIs. For this, we propose the use of specialized sensors such as strain gages, advanced conditioning circuits and signal processing tools such as sensor fusion. We believe that careful electronic instrumentation design may lead to more responsive instruments.

Gelatin device for the delivery of growth factors involved in endochondral ossification.

PubMed

Ahrens, Lucas A J; Vonwil, Daniel; Christensen, Jon; Shastri, V Prasad

2017-01-01

Controlled release drug delivery systems are well established as oral and implantable dosage forms. However, the controlled release paradigm can also be used to present complex soluble signals responsible for cellular organization during development. Endochondral ossification (EO), the developmental process of bone formation from a cartilage matrix is controlled by several soluble signals with distinct functions that vary in structure, molecular weight and stability. This makes delivering them from a single vehicle rather challenging. Herein, a gelatin-based delivery system suitable for the delivery of small molecules as well as recombinant human (rh) proteins (rhWNT3A, rhFGF2, rhVEGF, rhBMP4) is reported. The release behavior and biological activity of the released molecules was validated using analytical and biological assays, including cell reporter systems. The simplicity of fabrication of the gelatin device should foster its adaptation by the diverse scientific community interested in interrogating developmental processes, in vivo.

Gelatin device for the delivery of growth factors involved in endochondral ossification

PubMed Central

Ahrens, Lucas A. J.; Vonwil, Daniel; Christensen, Jon

2017-01-01

Controlled release drug delivery systems are well established as oral and implantable dosage forms. However, the controlled release paradigm can also be used to present complex soluble signals responsible for cellular organization during development. Endochondral ossification (EO), the developmental process of bone formation from a cartilage matrix is controlled by several soluble signals with distinct functions that vary in structure, molecular weight and stability. This makes delivering them from a single vehicle rather challenging. Herein, a gelatin-based delivery system suitable for the delivery of small molecules as well as recombinant human (rh) proteins (rhWNT3A, rhFGF2, rhVEGF, rhBMP4) is reported. The release behavior and biological activity of the released molecules was validated using analytical and biological assays, including cell reporter systems. The simplicity of fabrication of the gelatin device should foster its adaptation by the diverse scientific community interested in interrogating developmental processes, in vivo. PMID:28380024

The DISC Quotient

NASA Astrophysics Data System (ADS)

Elliott, John R.; Baxter, Stephen

2012-09-01

D.I.S.C: Decipherment Impact of a Signal's Content. The authors present a numerical method to characterise the significance of the receipt of a complex and potentially decipherable signal from extraterrestrial intelligence (ETI). The purpose of the scale is to facilitate the public communication of work on any such claimed signal, as such work proceeds, and to assist in its discussion and interpretation. Building on a "position" paper rationale, this paper looks at the DISC quotient proposed and develops the algorithmic steps and comprising measures that form this post detection strategy for information dissemination, based on prior work on message detection, decipherment. As argued, we require a robust and incremental strategy, to disseminate timely, accurate and meaningful information, to the scientific community and the general public, in the event we receive an "alien" signal that displays decipherable information. This post-detection strategy is to serve as a stepwise algorithm for a logical approach to information extraction and a vehicle for sequential information dissemination, to manage societal impact. The "DISC Quotient", which is based on signal analysis processing stages, includes factors based on the signal's data quantity, structure, affinity to known human languages, and likely decipherment times. Comparisons with human and other phenomena are included as a guide to assessing likely societal impact. It is submitted that the development, refinement and implementation of DISC as an integral strategy, during the complex processes involved in post detection and decipherment, is essential if we wish to minimize disruption and optimize dissemination.

Review of current GPS methodologies for producing accurate time series and their error sources

NASA Astrophysics Data System (ADS)

He, Xiaoxing; Montillet, Jean-Philippe; Fernandes, Rui; Bos, Machiel; Yu, Kegen; Hua, Xianghong; Jiang, Weiping

2017-05-01

The Global Positioning System (GPS) is an important tool to observe and model geodynamic processes such as plate tectonics and post-glacial rebound. In the last three decades, GPS has seen tremendous advances in the precision of the measurements, which allow researchers to study geophysical signals through a careful analysis of daily time series of GPS receiver coordinates. However, the GPS observations contain errors and the time series can be described as the sum of a real signal and noise. The signal itself can again be divided into station displacements due to geophysical causes and to disturbing factors. Examples of the latter are errors in the realization and stability of the reference frame and corrections due to ionospheric and tropospheric delays and GPS satellite orbit errors. There is an increasing demand on detecting millimeter to sub-millimeter level ground displacement signals in order to further understand regional scale geodetic phenomena hence requiring further improvements in the sensitivity of the GPS solutions. This paper provides a review spanning over 25 years of advances in processing strategies, error mitigation methods and noise modeling for the processing and analysis of GPS daily position time series. The processing of the observations is described step-by-step and mainly with three different strategies in order to explain the weaknesses and strengths of the existing methodologies. In particular, we focus on the choice of the stochastic model in the GPS time series, which directly affects the estimation of the functional model including, for example, tectonic rates, seasonal signals and co-seismic offsets. Moreover, the geodetic community continues to develop computational methods to fully automatize all phases from analysis of GPS time series. This idea is greatly motivated by the large number of GPS receivers installed around the world for diverse applications ranging from surveying small deformations of civil engineering structures (e.g., subsidence of the highway bridge) to the detection of particular geophysical signals.

AnyWave: a cross-platform and modular software for visualizing and processing electrophysiological signals.

PubMed

Colombet, B; Woodman, M; Badier, J M; Bénar, C G

2015-03-15

The importance of digital signal processing in clinical neurophysiology is growing steadily, involving clinical researchers and methodologists. There is a need for crossing the gap between these communities by providing efficient delivery of newly designed algorithms to end users. We have developed such a tool which both visualizes and processes data and, additionally, acts as a software development platform. AnyWave was designed to run on all common operating systems. It provides access to a variety of data formats and it employs high fidelity visualization techniques. It also allows using external tools as plug-ins, which can be developed in languages including C++, MATLAB and Python. In the current version, plug-ins allow computation of connectivity graphs (non-linear correlation h2) and time-frequency representation (Morlet wavelets). The software is freely available under the LGPL3 license. AnyWave is designed as an open, highly extensible solution, with an architecture that permits rapid delivery of new techniques to end users. We have developed AnyWave software as an efficient neurophysiological data visualizer able to integrate state of the art techniques. AnyWave offers an interface well suited to the needs of clinical research and an architecture designed for integrating new tools. We expect this software to strengthen the collaboration between clinical neurophysiologists and researchers in biomedical engineering and signal processing. Copyright © 2015 Elsevier B.V. All rights reserved.

NeuroPigPen: A Scalable Toolkit for Processing Electrophysiological Signal Data in Neuroscience Applications Using Apache Pig

PubMed Central

Sahoo, Satya S.; Wei, Annan; Valdez, Joshua; Wang, Li; Zonjy, Bilal; Tatsuoka, Curtis; Loparo, Kenneth A.; Lhatoo, Samden D.

2016-01-01

The recent advances in neurological imaging and sensing technologies have led to rapid increase in the volume, rate of data generation, and variety of neuroscience data. This “neuroscience Big data” represents a significant opportunity for the biomedical research community to design experiments using data with greater timescale, large number of attributes, and statistically significant data size. The results from these new data-driven research techniques can advance our understanding of complex neurological disorders, help model long-term effects of brain injuries, and provide new insights into dynamics of brain networks. However, many existing neuroinformatics data processing and analysis tools were not built to manage large volume of data, which makes it difficult for researchers to effectively leverage this available data to advance their research. We introduce a new toolkit called NeuroPigPen that was developed using Apache Hadoop and Pig data flow language to address the challenges posed by large-scale electrophysiological signal data. NeuroPigPen is a modular toolkit that can process large volumes of electrophysiological signal data, such as Electroencephalogram (EEG), Electrocardiogram (ECG), and blood oxygen levels (SpO2), using a new distributed storage model called Cloudwave Signal Format (CSF) that supports easy partitioning and storage of signal data on commodity hardware. NeuroPigPen was developed with three design principles: (a) Scalability—the ability to efficiently process increasing volumes of data; (b) Adaptability—the toolkit can be deployed across different computing configurations; and (c) Ease of programming—the toolkit can be easily used to compose multi-step data processing pipelines using high-level programming constructs. The NeuroPigPen toolkit was evaluated using 750 GB of electrophysiological signal data over a variety of Hadoop cluster configurations ranging from 3 to 30 Data nodes. The evaluation results demonstrate that the toolkit is highly scalable and adaptable, which makes it suitable for use in neuroscience applications as a scalable data processing toolkit. As part of the ongoing extension of NeuroPigPen, we are developing new modules to support statistical functions to analyze signal data for brain connectivity research. In addition, the toolkit is being extended to allow integration with scientific workflow systems. NeuroPigPen is released under BSD license at: https://sites.google.com/a/case.edu/neuropigpen/. PMID:27375472

NeuroPigPen: A Scalable Toolkit for Processing Electrophysiological Signal Data in Neuroscience Applications Using Apache Pig.

PubMed

Sahoo, Satya S; Wei, Annan; Valdez, Joshua; Wang, Li; Zonjy, Bilal; Tatsuoka, Curtis; Loparo, Kenneth A; Lhatoo, Samden D

2016-01-01

The recent advances in neurological imaging and sensing technologies have led to rapid increase in the volume, rate of data generation, and variety of neuroscience data. This "neuroscience Big data" represents a significant opportunity for the biomedical research community to design experiments using data with greater timescale, large number of attributes, and statistically significant data size. The results from these new data-driven research techniques can advance our understanding of complex neurological disorders, help model long-term effects of brain injuries, and provide new insights into dynamics of brain networks. However, many existing neuroinformatics data processing and analysis tools were not built to manage large volume of data, which makes it difficult for researchers to effectively leverage this available data to advance their research. We introduce a new toolkit called NeuroPigPen that was developed using Apache Hadoop and Pig data flow language to address the challenges posed by large-scale electrophysiological signal data. NeuroPigPen is a modular toolkit that can process large volumes of electrophysiological signal data, such as Electroencephalogram (EEG), Electrocardiogram (ECG), and blood oxygen levels (SpO2), using a new distributed storage model called Cloudwave Signal Format (CSF) that supports easy partitioning and storage of signal data on commodity hardware. NeuroPigPen was developed with three design principles: (a) Scalability-the ability to efficiently process increasing volumes of data; (b) Adaptability-the toolkit can be deployed across different computing configurations; and (c) Ease of programming-the toolkit can be easily used to compose multi-step data processing pipelines using high-level programming constructs. The NeuroPigPen toolkit was evaluated using 750 GB of electrophysiological signal data over a variety of Hadoop cluster configurations ranging from 3 to 30 Data nodes. The evaluation results demonstrate that the toolkit is highly scalable and adaptable, which makes it suitable for use in neuroscience applications as a scalable data processing toolkit. As part of the ongoing extension of NeuroPigPen, we are developing new modules to support statistical functions to analyze signal data for brain connectivity research. In addition, the toolkit is being extended to allow integration with scientific workflow systems. NeuroPigPen is released under BSD license at: https://sites.google.com/a/case.edu/neuropigpen/.

EARLINET Single Calculus Chain - technical - Part 1: Pre-processing of raw lidar data

NASA Astrophysics Data System (ADS)

D'Amico, G.; Amodeo, A.; Mattis, I.; Freudenthaler, V.; Pappalardo, G.

2015-10-01

In this paper we describe an automatic tool for the pre-processing of lidar data called ELPP (EARLINET Lidar Pre-Processor). It is one of two calculus modules of the EARLINET Single Calculus Chain (SCC), the automatic tool for the analysis of EARLINET data. The ELPP is an open source module that executes instrumental corrections and data handling of the raw lidar signals, making the lidar data ready to be processed by the optical retrieval algorithms. According to the specific lidar configuration, the ELPP automatically performs dead-time correction, atmospheric and electronic background subtraction, gluing of lidar signals, and trigger-delay correction. Moreover, the signal-to-noise ratio of the pre-processed signals can be improved by means of configurable time integration of the raw signals and/or spatial smoothing. The ELPP delivers the statistical uncertainties of the final products by means of error propagation or Monte Carlo simulations. During the development of the ELPP module, particular attention has been payed to make the tool flexible enough to handle all lidar configurations currently used within the EARLINET community. Moreover, it has been designed in a modular way to allow an easy extension to lidar configurations not yet implemented. The primary goal of the ELPP module is to enable the application of quality-assured procedures in the lidar data analysis starting from the raw lidar data. This provides the added value of full traceability of each delivered lidar product. Several tests have been performed to check the proper functioning of the ELPP module. The whole SCC has been tested with the same synthetic data sets, which were used for the EARLINET algorithm inter-comparison exercise. The ELPP module has been successfully employed for the automatic near-real-time pre-processing of the raw lidar data measured during several EARLINET inter-comparison campaigns as well as during intense field campaigns.

A FPGA-based Fast Converging Digital Adaptive Filter for Real-time RFI Mitigation on Ground Based Radio Telescopes

NASA Astrophysics Data System (ADS)

Finger, R.; Curotto, F.; Fuentes, R.; Duan, R.; Bronfman, L.; Li, D.

2018-02-01

Radio Frequency Interference (RFI) is a growing concern in the radio astronomy community. Single-dish telescopes are particularly susceptible to RFI. Several methods have been developed to cope with RF-polluted environments, based on flagging, excision, and real-time blanking, among others. All these methods produce some degree of data loss or require assumptions to be made on the astronomical signal. We report the development of a real-time, digital adaptive filter implemented on a Field Programmable Gate Array (FPGA) capable of processing 4096 spectral channels in a 1 GHz of instantaneous bandwidth. The filter is able to cancel a broad range of interference signals and quickly adapt to changes on the RFI source, minimizing the data loss without any assumption on the astronomical or interfering signal properties. The speed of convergence (for a decrease to a 1%) was measured to be 208.1 μs for a broadband noise-like RFI signal and 125.5 μs for a multiple-carrier RFI signal recorded at the FAST radio telescope.

Microbial Surface Colonization and Biofilm Development in Marine Environments

PubMed Central

2015-01-01

SUMMARY Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific community-level microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration. PMID:26700108

Microbial Surface Colonization and Biofilm Development in Marine Environments.

PubMed

Dang, Hongyue; Lovell, Charles R

2016-03-01

Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific community-level microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Role of cyclic diguanylate in affecting microbial community shifts at different pH during the operation of simultaneous partial nitrification, anammox and denitrification process.

PubMed

Wang, Chao; Liu, Sitong; Xu, Xiaochen; Guo, Yongzhao; Yang, Fenglin; Wang, Dong

2018-05-08

The intracellular cyclic diguanylate acid (c-di-GMP) has emerged as a prominent second signal molecule that coordinates sessile-motile transition and biofilm formation in many bacteria. Herein, we study the role of c-di-GMP in affecting microbial community shifts at different pH levels during simultaneous partial nitrification, anammox and denitrification process (SNAD) in integrated fixed film activated sludge (IFAS) reactor. The results demonstrated that the contents of c-di-GMP notably decreased in suspended sludge, whereas the contents of c-di-GMP in biofilm had no significant change as pH gradually increased from 7.5 to 8.5. Most of the bacteria (Blastocatella, Brevundimonas) with flagella that have been reported to be regulated by c-di-GMP were present in suspended sludge, and the microbial community structure of suspended sludge had obvious change than biofilm. The increased alkaline pH reduced intracellular c-di-GMP content for increasing the motility of bacteria to be washed out from the reactor, causing the microbial community shifts in suspended sludge. This change would lead to the increase of nitrite-oxidizing bacteria which would inhibit anammox activity. Overall, this study provided more comprehensive information regarding the shifts of microbial community induced by c-di-GMP in SNAD-IFAS reactor. Copyright © 2018. Published by Elsevier B.V.

Emergent Phototactic Responses of Cyanobacteria under Complex Light Regimes

PubMed Central

Chau, Rosanna Man Wah

2017-01-01

ABSTRACT Environmental cues can stimulate a variety of single-cell responses, as well as collective behaviors that emerge within a bacterial community. These responses require signal integration and transduction, which can occur on a variety of time scales and often involve feedback between processes, for example, between growth and motility. Here, we investigate the dynamics of responses of the phototactic, unicellular cyanobacterium Synechocystis sp. PCC6803 to complex light inputs that simulate the natural environments that cells typically encounter. We quantified single-cell motility characteristics in response to light of different wavelengths and intensities. We found that red and green light primarily affected motility bias rather than speed, while blue light inhibited motility altogether. When light signals were simultaneously presented from different directions, cells exhibited phototaxis along the vector sum of the light directions, indicating that cells can sense and combine multiple signals into an integrated motility response. Under a combination of antagonistic light signal regimes (phototaxis-promoting green light and phototaxis-inhibiting blue light), the ensuing bias was continuously tuned by competition between the wavelengths, and the community response was dependent on both bias and cell growth. The phototactic dynamics upon a rapid light shift revealed a wavelength dependence on the time scales of photoreceptor activation/deactivation. Thus, Synechocystis cells achieve exquisite integration of light inputs at the cellular scale through continuous tuning of motility, and the pattern of collective behavior depends on single-cell motility and population growth. PMID:28270586

New Ecuadorian VLF and ELF receiver for study the ionosphere

NASA Astrophysics Data System (ADS)

Lopez, Ericson; Montenegro, Jefferson; Vasconez, Michael; Vicente, Klever

Crucial physical phenomena occur in the equatorial atmosphere and ionosphere, which are currently understudied and poorly understood. Thus, scientific campaigns for monitoring the equatorial region are required in order to provide the necessary data for the physical models. Ecuador is located in strategic geographical position where these studies can be performed, providing quality data for the scientific community working in understanding the nature of these physical systems. The Quito Astronomical Observatory (QAO) of National Polytechnic School is moving in this direction by promoting research in space sciences for the study of the equatorial zone. With the participation and the valuable collaboration of international initiatives such us AWESOME, MAGDAS, SAVNET and CALLISTO, the Quito Observatory is establishing a new space physics division on the basis of the International Space Weather Initiative. As part of this project, in the QAO has been designed a new system for acquisition and processing VLF and ELF signals propagating in the ionosphere. The Labview Software is used to filtering, processing and conditioning the received signals, avoiding in this way 60 percent of the analog components present in a common receiver. The same software have been programmed to create the spectrograms and the amplitude and phase diagrams of the radio signals. The data is stored neatly in files that can be processed even with other applications.

Cophylogenetic signal is detectable in pollination interactions across ecological scales.

PubMed

Hutchinson, Matthew C; Cagua, Edgar Fernando; Stouffer, Daniel B

2017-10-01

That evolutionary history can influence the way that species interact is a basic tenet of evolutionary ecology. However, when the role of evolution in determining ecological interactions is investigated, focus typically centers on just one side of the interaction. A cophylogenetic signal, the congruence of evolutionary history across both sides of an ecological interaction, extends these previous explorations and provides a more complete picture of how evolutionary patterns influence the way species interact. To date, cophylogenetic signal has most typically been studied in interactions that occur between fine taxonomic clades that show high intimacy. In this study, we took an alternative approach and made an exhaustive assessment of cophylogeny in pollination interactions. To do so, we assessed the strength of cophylogenetic signal at four distinct scales of pollination interaction: (1) across plant-pollinator associations globally, (2) in local pollination communities, (3) within the modular structure of those communities, and (4) in individual modules. We did so using a globally distributed dataset comprised of 54 pollination networks, over 4000 species, and over 12,000 interactions. Within these data, we detected cophylogenetic signal at all four scales. Cophylogenetic signal was found at the level of plant-pollinator interactions on a global scale and in the majority of pollination communities. At the scale defined by the modular structure within those communities, however, we observed a much weaker cophylogenetic signal. Cophylogenetic signal was detectable in a significant proportion of individual modules and most typically when within-module phylogenetic diversity was low. In sum, the detection of cophylogenetic signal in pollination interactions across scales provides a new dimension to the story of how past evolution shapes extant pollinator-angiosperm interactions. © 2017 by the Ecological Society of America.

User expectations for multibeam echo sounders backscatter strength data-looking back into the future

NASA Astrophysics Data System (ADS)

Lucieer, Vanessa; Roche, Marc; Degrendele, Koen; Malik, Mashkoor; Dolan, Margaret; Lamarche, Geoffroy

2018-06-01

With the ability of multibeam echo sounders (MBES) to measure backscatter strength (BS) as a function of true angle of insonification across the seafloor, came a new recognition of the potential of backscatter measurements to remotely characterize the properties of the seafloor. Advances in transducer design, digital electronics, signal processing capabilities, navigation, and graphic display devices, have improved the resolution and particularly the dynamic range available to sonar and processing software manufacturers. Alongside these improvements the expectations of what the data can deliver has also grown. In this paper, we identify these user-expectations and explore how MBES backscatter is utilized by different communities involved in marine seabed research at present, and the aspirations that these communities have for the data in the future. The results presented here are based on a user survey conducted by the GeoHab (Marine Geological and Biological Habitat Mapping) association. This paper summarises the different processing procedures employed to extract useful information from MBES backscatter data and the various intentions for which the user community collect the data. We show how a range of backscatter output products are generated from the different processing procedures, and how these results are taken up by different scientific disciplines, and also identify common constraints in handling MBES BS data. Finally, we outline our expectations for the future of this unique and important data source for seafloor mapping and characterisation.

Changes in the microbial communities during co-composting of digestates.

PubMed

Franke-Whittle, Ingrid H; Confalonieri, Alberto; Insam, Heribert; Schlegelmilch, Mirko; Körner, Ina

2014-03-01

Anaerobic digestion is a waste treatment method which is of increasing interest worldwide. At the end of the process, a digestate remains, which can gain added value by being composted. A study was conducted in order to investigate microbial community dynamics during the composting process of a mixture of anaerobic digestate (derived from the anaerobic digestion of municipal food waste), green wastes and a screened compost (green waste/kitchen waste compost), using the COMPOCHIP microarray. The composting process showed a typical temperature development, and the highest degradation rates occurred during the first 14 days of composting, as seen from the elevated CO2 content in the exhaust air. With an exception of elevated nitrite and nitrate levels in the day 34 samples, physical-chemical parameters for all compost samples collected during the 63 day process indicated typical composting conditions. The microbial communities changed over the 63 days of composting. According to principal component analysis of the COMPOCHIP microarray results, compost samples from the start of the experiment were found to cluster most closely with the digestate and screened compost samples. The green waste samples were found to group separately. All starting materials investigated were found to yield fewer and lower signals when compared to the samples collected during the composting experiment. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Similar environments but diverse fates: Responses of budding yeast to nutrient deprivation

PubMed Central

Honigberg, Saul M.

2016-01-01

Diploid budding yeast (Saccharomyces cerevisiae) can adopt one of several alternative differentiation fates in response to nutrient limitation, and each of these fates provides distinct biological functions. When different strain backgrounds are taken into account, these various fates occur in response to similar environmental cues, are regulated by the same signal transduction pathways, and share many of the same master regulators. I propose that the relationships between fate choice, environmental cues and signaling pathways are not Boolean, but involve graded levels of signals, pathway activation and master-regulator activity. In the absence of large differences between environmental cues, small differences in the concentration of cues may be reinforced by cell-to-cell signals. These signals are particularly essential for fate determination within communities, such as colonies and biofilms, where fate choice varies dramatically from one region of the community to another. The lack of Boolean relationships between cues, signaling pathways, master regulators and cell fates may allow yeast communities to respond appropriately to the wide range of environments they encounter in nature. PMID:27917388

Molecular analysis of meso- and thermophilic microbiota associated with anaerobic biowaste degradation

PubMed Central

2012-01-01

Background Microbial anaerobic digestion (AD) is used as a waste treatment process to degrade complex organic compounds into methane. The archaeal and bacterial taxa involved in AD are well known, whereas composition of the fungal community in the process has been less studied. The present study aimed to reveal the composition of archaeal, bacterial and fungal communities in response to increasing organic loading in mesophilic and thermophilic AD processes by applying 454 amplicon sequencing technology. Furthermore, a DNA microarray method was evaluated in order to develop a tool for monitoring the microbiological status of AD. Results The 454 sequencing showed that the diversity and number of bacterial taxa decreased with increasing organic load, while archaeal i.e. methanogenic taxa remained more constant. The number and diversity of fungal taxa increased during the process and varied less in composition with process temperature than bacterial and archaeal taxa, even though the fungal diversity increased with temperature as well. Evaluation of the microarray using AD sample DNA showed correlation of signal intensities with sequence read numbers of corresponding target groups. The sensitivity of the test was found to be about 1%. Conclusions The fungal community survives in anoxic conditions and grows with increasing organic loading, suggesting that Fungi may contribute to the digestion by metabolising organic nutrients for bacterial and methanogenic groups. The microarray proof of principle tests suggest that the method has the potential for semiquantitative detection of target microbial groups given that comprehensive sequence data is available for probe design. PMID:22727142

Detection and imaging of quorum sensing in Pseudomonas aeruginosa biofilm communities by surface-enhanced resonance Raman scattering

PubMed Central

Bodelón, Gustavo; Montes-García, Verónica; López-Puente, Vanesa; Hill, Eric H.; Hamon, Cyrille; Sanz-Ortiz, Marta N.; Rodal-Cedeira, Sergio; Costas, Celina; Celiksoy, Sirin; Pérez-Juste, Ignacio; Scarabelli, Leonardo; Porta, Andrea La; Pérez-Juste, Jorge; Pastoriza-Santos, Isabel

2016-01-01

Most bacteria in nature exist as biofilms, which support intercellular signaling processes such as quorum sensing (QS), a cell-to-cell communication mechanism that allows bacteria to monitor and respond to cell density and changes in the environment. Because QS and biofilms are involved in the ability of bacteria to cause disease, there is a need for the development of methods for the non-invasive analysis of QS in natural bacterial populations. Here, by using surface-enhanced resonance Raman scattering spectroscopy, we report rationally designed nanostructured plasmonic substrates for the in-situ, label-free detection of a QS signaling metabolite in growing Pseudomonas aeruginosa biofilms and microcolonies. The in situ, non-invasive plasmonic imaging of QS in biofilms provides a powerful analytical approach for studying intercellular communication on the basis of secreted molecules as signals. PMID:27500808

A synthetic genetic edge detection program.

PubMed

Tabor, Jeffrey J; Salis, Howard M; Simpson, Zachary Booth; Chevalier, Aaron A; Levskaya, Anselm; Marcotte, Edward M; Voigt, Christopher A; Ellington, Andrew D

2009-06-26

Edge detection is a signal processing algorithm common in artificial intelligence and image recognition programs. We have constructed a genetically encoded edge detection algorithm that programs an isogenic community of E. coli to sense an image of light, communicate to identify the light-dark edges, and visually present the result of the computation. The algorithm is implemented using multiple genetic circuits. An engineered light sensor enables cells to distinguish between light and dark regions. In the dark, cells produce a diffusible chemical signal that diffuses into light regions. Genetic logic gates are used so that only cells that sense light and the diffusible signal produce a positive output. A mathematical model constructed from first principles and parameterized with experimental measurements of the component circuits predicts the performance of the complete program. Quantitatively accurate models will facilitate the engineering of more complex biological behaviors and inform bottom-up studies of natural genetic regulatory networks.

A Synthetic Genetic Edge Detection Program

PubMed Central

Tabor, Jeffrey J.; Salis, Howard; Simpson, Zachary B.; Chevalier, Aaron A.; Levskaya, Anselm; Marcotte, Edward M.; Voigt, Christopher A.; Ellington, Andrew D.

2009-01-01

Summary Edge detection is a signal processing algorithm common in artificial intelligence and image recognition programs. We have constructed a genetically encoded edge detection algorithm that programs an isogenic community of E.coli to sense an image of light, communicate to identify the light-dark edges, and visually present the result of the computation. The algorithm is implemented using multiple genetic circuits. An engineered light sensor enables cells to distinguish between light and dark regions. In the dark, cells produce a diffusible chemical signal that diffuses into light regions. Genetic logic gates are used so that only cells that sense light and the diffusible signal produce a positive output. A mathematical model constructed from first principles and parameterized with experimental measurements of the component circuits predicts the performance of the complete program. Quantitatively accurate models will facilitate the engineering of more complex biological behaviors and inform bottom-up studies of natural genetic regulatory networks. PMID:19563759

Traffic Light Geography: A Fifth Grade Community Project.

ERIC Educational Resources Information Center

Zirschky, E. Dwight

1989-01-01

Describes a community study project that uses history and the five fundamental themes of geography as a framework. The project involves organizing committees to study the need for a traffic signal in a small town. By studying various dimensions of the issue, the committees are able to demonstrate the need for a signal. (KO)

Quorum sensing is a language of chemical signals and plays an ecological role in algal-bacterial interactions

PubMed Central

Zhou, Jin; Lyu, Yihua; Richlen, Mindy; Anderson, Donald M.; Cai, Zhonghua

2017-01-01

Algae are ubiquitous in the marine environment, and the ways in which they interact with bacteria are of particular interest in marine ecology field. The interactions between primary producers and bacteria impact the physiology of both partners, alter the chemistry of their environment, and shape microbial diversity. Although algal-bacterial interactions are well known and studied, information regarding the chemical-ecological role of this relationship remains limited, particularly with respect to quorum sensing (QS), which is a system of stimuli and response correlated to population density. In the microbial biosphere, QS is pivotal in driving community structure and regulating behavioral ecology, including biofilm formation, virulence, antibiotic resistance, swarming motility, and secondary metabolite production. Many marine habitats, such as the phycosphere, harbour diverse populations of microorganisms and various signal languages (such as QS-based autoinducers). QS-mediated interactions widely influence algal-bacterial symbiotic relationships, which in turn determine community organization, population structure, and ecosystem functioning. Understanding infochemicals-mediated ecological processes may shed light on the symbiotic interactions between algae host and associated microbes. In this review, we summarize current achievements about how QS modulates microbial behavior, affects symbiotic relationships, and regulates phytoplankton chemical ecological processes. Additionally, we present an overview of QS-modulated co-evolutionary relationships between algae and bacterioplankton, and consider the potential applications and future perspectives of QS. PMID:28966438

Signal Acquisition Using AXIe

NASA Astrophysics Data System (ADS)

Narciso, Steven J.

2011-08-01

An emerging test and measurement standard called AXIe, AdvancedTCA extensions for Instrumentation, is expected to find wide acceptance within the Physics community as it offers many benefits to applications including shock, plasma, particle and nuclear physics. It is expected that many COTS (commercial off-the-shelf) signal conditioning, acquisition and processing modules will become available from a range of different suppliers. AXIe uses AdvancedTCA® as its basis, but then levers test and measurement industry standards such as PXI, IVI, and LXI to facilitate cooperation and plug-and-play interoperability between COTS instrument suppliers. AXIe's large board footprint and power allows high density in a 19" rack, enabling the development of high-performance signal conditioning, analog-to-digital conversion, and data processing, while offering channel count scalability inherent in modular systems. Synchronization between modules is flexible and provided by two triggering structures: a parallel trigger bus, and radially-distributed, time-matched point-to-point trigger lines. Inter-module communication is also provided with an adjacent module local bus allowing data transfer to 600 Gbits/s in each direction, for example between a front-end digitizer and DSP. AXIe allows embedding high performance computing and a range of COTS AdvancedTCA® computer blades are currently available that provide low cost alternatives to the development of custom signal processing modules. The availability of both LAN and PCI Express allow interconnection between modules, as well as industry-standard high-performance data paths to external host computer systems. AXIe delivers a powerful environment for custom module devel opment. As in the case of VXIbus and PXI before it, commercial development kits are expected to be available. This paper will give an overview of the architectural elements of AXIe 1.0, the compatibility model with AdvancedTCA, and signal acquisition performance of many of the AXIe structures.

Engineering chemical interactions in microbial communities.

PubMed

Kenny, Douglas J; Balskus, Emily P

2018-03-05

Microbes living within host-associated microbial communities (microbiotas) rely on chemical communication to interact with surrounding organisms. These interactions serve many purposes, from supplying the multicellular host with nutrients to antagonizing invading pathogens, and breakdown of chemical signaling has potentially negative consequences for both the host and microbiota. Efforts to engineer microbes to take part in chemical interactions represent a promising strategy for modulating chemical signaling within these complex communities. In this review, we discuss prominent examples of chemical interactions found within host-associated microbial communities, with an emphasis on the plant-root microbiota and the intestinal microbiota of animals. We then highlight how an understanding of such interactions has guided efforts to engineer microbes to participate in chemical signaling in these habitats. We discuss engineering efforts in the context of chemical interactions that enable host colonization, promote host health, and exclude pathogens. Finally, we describe prominent challenges facing this field and propose new directions for future engineering efforts.

IQM: An Extensible and Portable Open Source Application for Image and Signal Analysis in Java

PubMed Central

Kainz, Philipp; Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

2015-01-01

Image and signal analysis applications are substantial in scientific research. Both open source and commercial packages provide a wide range of functions for image and signal analysis, which are sometimes supported very well by the communities in the corresponding fields. Commercial software packages have the major drawback of being expensive and having undisclosed source code, which hampers extending the functionality if there is no plugin interface or similar option available. However, both variants cannot cover all possible use cases and sometimes custom developments are unavoidable, requiring open source applications. In this paper we describe IQM, a completely free, portable and open source (GNU GPLv3) image and signal analysis application written in pure Java. IQM does not depend on any natively installed libraries and is therefore runnable out-of-the-box. Currently, a continuously growing repertoire of 50 image and 16 signal analysis algorithms is provided. The modular functional architecture based on the three-tier model is described along the most important functionality. Extensibility is achieved using operator plugins, and the development of more complex workflows is provided by a Groovy script interface to the JVM. We demonstrate IQM’s image and signal processing capabilities in a proof-of-principle analysis and provide example implementations to illustrate the plugin framework and the scripting interface. IQM integrates with the popular ImageJ image processing software and is aiming at complementing functionality rather than competing with existing open source software. Machine learning can be integrated into more complex algorithms via the WEKA software package as well, enabling the development of transparent and robust methods for image and signal analysis. PMID:25612319

IQM: an extensible and portable open source application for image and signal analysis in Java.

PubMed

Kainz, Philipp; Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

2015-01-01

Image and signal analysis applications are substantial in scientific research. Both open source and commercial packages provide a wide range of functions for image and signal analysis, which are sometimes supported very well by the communities in the corresponding fields. Commercial software packages have the major drawback of being expensive and having undisclosed source code, which hampers extending the functionality if there is no plugin interface or similar option available. However, both variants cannot cover all possible use cases and sometimes custom developments are unavoidable, requiring open source applications. In this paper we describe IQM, a completely free, portable and open source (GNU GPLv3) image and signal analysis application written in pure Java. IQM does not depend on any natively installed libraries and is therefore runnable out-of-the-box. Currently, a continuously growing repertoire of 50 image and 16 signal analysis algorithms is provided. The modular functional architecture based on the three-tier model is described along the most important functionality. Extensibility is achieved using operator plugins, and the development of more complex workflows is provided by a Groovy script interface to the JVM. We demonstrate IQM's image and signal processing capabilities in a proof-of-principle analysis and provide example implementations to illustrate the plugin framework and the scripting interface. IQM integrates with the popular ImageJ image processing software and is aiming at complementing functionality rather than competing with existing open source software. Machine learning can be integrated into more complex algorithms via the WEKA software package as well, enabling the development of transparent and robust methods for image and signal analysis.

Deep Sequencing of the Medicago truncatula Root Transcriptome Reveals a Massive and Early Interaction between Nodulation Factor and Ethylene Signals1[OPEN

PubMed Central

Larrainzar, Estíbaliz; Riely, Brendan K.; Kim, Sang Cheol; Carrasquilla-Garcia, Noelia; Yu, Hee-Ju; Hwang, Hyun-Ju; Oh, Mijin; Kim, Goon Bo; Surendrarao, Anandkumar K.; Chasman, Deborah; Siahpirani, Alireza F.; Penmetsa, Ramachandra V.; Lee, Gang-Seob; Kim, Namshin; Roy, Sushmita; Mun, Jeong-Hwan; Cook, Douglas R.

2015-01-01

The legume-rhizobium symbiosis is initiated through the activation of the Nodulation (Nod) factor-signaling cascade, leading to a rapid reprogramming of host cell developmental pathways. In this work, we combine transcriptome sequencing with molecular genetics and network analysis to quantify and categorize the transcriptional changes occurring in roots of Medicago truncatula from minutes to days after inoculation with Sinorhizobium medicae. To identify the nature of the inductive and regulatory cues, we employed mutants with absent or decreased Nod factor sensitivities (i.e. Nodulation factor perception and Lysine motif domain-containing receptor-like kinase3, respectively) and an ethylene (ET)-insensitive, Nod factor-hypersensitive mutant (sickle). This unique data set encompasses nine time points, allowing observation of the symbiotic regulation of diverse biological processes with high temporal resolution. Among the many outputs of the study is the early Nod factor-induced, ET-regulated expression of ET signaling and biosynthesis genes. Coupled with the observation of massive transcriptional derepression in the ET-insensitive background, these results suggest that Nod factor signaling activates ET production to attenuate its own signal. Promoter:β-glucuronidase fusions report ET biosynthesis both in root hairs responding to rhizobium as well as in meristematic tissue during nodule organogenesis and growth, indicating that ET signaling functions at multiple developmental stages during symbiosis. In addition, we identified thousands of novel candidate genes undergoing Nod factor-dependent, ET-regulated expression. We leveraged the power of this large data set to model Nod factor- and ET-regulated signaling networks using MERLIN, a regulatory network inference algorithm. These analyses predict key nodes regulating the biological process impacted by Nod factor perception. We have made these results available to the research community through a searchable online resource. PMID:26175514

Exploring the complementarity of THz pulse imaging and DCE-MRIs: Toward a unified multi-channel classification and a deep learning framework.

PubMed

Yin, X-X; Zhang, Y; Cao, J; Wu, J-L; Hadjiloucas, S

2016-12-01

We provide a comprehensive account of recent advances in biomedical image analysis and classification from two complementary imaging modalities: terahertz (THz) pulse imaging and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The work aims to highlight underlining commonalities in both data structures so that a common multi-channel data fusion framework can be developed. Signal pre-processing in both datasets is discussed briefly taking into consideration advances in multi-resolution analysis and model based fractional order calculus system identification. Developments in statistical signal processing using principal component and independent component analysis are also considered. These algorithms have been developed independently by the THz-pulse imaging and DCE-MRI communities, and there is scope to place them in a common multi-channel framework to provide better software standardization at the pre-processing de-noising stage. A comprehensive discussion of feature selection strategies is also provided and the importance of preserving textural information is highlighted. Feature extraction and classification methods taking into consideration recent advances in support vector machine (SVM) and extreme learning machine (ELM) classifiers and their complex extensions are presented. An outlook on Clifford algebra classifiers and deep learning techniques suitable to both types of datasets is also provided. The work points toward the direction of developing a new unified multi-channel signal processing framework for biomedical image analysis that will explore synergies from both sensing modalities for inferring disease proliferation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The IMUTUS interactive music tuition system

NASA Astrophysics Data System (ADS)

Tambouratzis, George; Bakamidis, Stelios; Dologlou, Ioannis; Carayannis, George; Dendrinos, Markos

2002-05-01

This presentation focuses on the IMUTUS project, which concerns the creation of an innovative method for training users on traditional musical instruments with no MIDI (Musical Instrument Digital Interface) output. The entities collaborating in IMUTUS are ILSP (coordinator), EXODUS, SYSTEMA, DSI, SMF, GRAME, and KTH. The IMUTUS effectiveness is enhanced via an advanced user interface incorporating multimedia techniques. Internet plays a pivotal role during training, the student receiving guidance over the net from a specially created teacher group. Interactiveness is emphasized via automatic-scoring tools, which provide fast yet accurate feedback to the user, while virtual reality methods assist the student in perfecting his technique. IMUTUS incorporates specialized recognition technology for the transformation of acoustic signals and music scores to MIDI format and incorporation in the training process. This process is enhanced by periodically enriching the score database, while customization to each user's requirements is supported. This work is partially supported by European Community under the Information Society Technology (IST) RTD programme. The authors are solely responsible for the content of this communication. It does not represent the opinion of the European Community, and the European Community is not responsible for any use that might be made of data appearing therein.

A cell-phone-based brain-computer interface for communication in daily life

NASA Astrophysics Data System (ADS)

Wang, Yu-Te; Wang, Yijun; Jung, Tzyy-Ping

2011-04-01

Moving a brain-computer interface (BCI) system from a laboratory demonstration to real-life applications still poses severe challenges to the BCI community. This study aims to integrate a mobile and wireless electroencephalogram (EEG) system and a signal-processing platform based on a cell phone into a truly wearable and wireless online BCI. Its practicality and implications in a routine BCI are demonstrated through the realization and testing of a steady-state visual evoked potential (SSVEP)-based BCI. This study implemented and tested online signal processing methods in both time and frequency domains for detecting SSVEPs. The results of this study showed that the performance of the proposed cell-phone-based platform was comparable, in terms of the information transfer rate, with other BCI systems using bulky commercial EEG systems and personal computers. To the best of our knowledge, this study is the first to demonstrate a truly portable, cost-effective and miniature cell-phone-based platform for online BCIs.

A cell-phone-based brain-computer interface for communication in daily life.

PubMed

Wang, Yu-Te; Wang, Yijun; Jung, Tzyy-Ping

2011-04-01

Moving a brain-computer interface (BCI) system from a laboratory demonstration to real-life applications still poses severe challenges to the BCI community. This study aims to integrate a mobile and wireless electroencephalogram (EEG) system and a signal-processing platform based on a cell phone into a truly wearable and wireless online BCI. Its practicality and implications in a routine BCI are demonstrated through the realization and testing of a steady-state visual evoked potential (SSVEP)-based BCI. This study implemented and tested online signal processing methods in both time and frequency domains for detecting SSVEPs. The results of this study showed that the performance of the proposed cell-phone-based platform was comparable, in terms of the information transfer rate, with other BCI systems using bulky commercial EEG systems and personal computers. To the best of our knowledge, this study is the first to demonstrate a truly portable, cost-effective and miniature cell-phone-based platform for online BCIs.

Reduction of produced elementary sulfur in denitrifying sulfide removal process.

PubMed

Zhou, Xu; Liu, Lihong; Chen, Chuan; Ren, Nanqi; Wang, Aijie; Lee, Duu-Jong

2011-05-01

Denitrifying sulfide removal (DSR) processes simultaneously convert sulfide, nitrate, and chemical oxygen demand from industrial wastewater into elemental sulfur, dinitrogen gas, and carbon dioxide, respectively. The failure of a DSR process is signaled by high concentrations of sulfide in reactor effluent. Conventionally, DSR reactor failure is blamed for overcompetition for heterotroph to autotroph communities. This study indicates that the elementary sulfur produced by oxidizing sulfide that is a recoverable resource from sulfide-laden wastewaters can be reduced back to sulfide by sulfur-reducing Methanobacterium sp. The Methanobacterium sp. was stimulated with excess organic carbon (acetate) when nitrite was completely consumed by heterotrophic denitrifiers. Adjusting hydraulic retention time of a DSR reactor when nitrite is completely consumed provides an additional control variable for maximizing DSR performance.

EMPTAC (Electromagnetic Pulse Test Aircraft) User’s Guide.

DTIC Science & Technology

1988-04-01

8217Jhe 5 JJ 5 1.2 OBJECTIVES - Elf , The objectives of this document are to: 0 Point out major areas of interest which a user must consider while planning...to bridge the gap between the research and development (R&D) and the operational communities . It provides a vehicle to demonstrate and correlate the...digital communication from the ALT. The test responses are processed through the signal conditioners of the ALT and routed to the ALR. From the ALR

Biofilms in lab and nature: a molecular geneticist's voyage to microbial ecology.

PubMed

Kolter, Roberto

2010-03-01

This article reviews the latest findings on how extracellular signaling controls cell fate determination during the process of biofilm formation by Bacillus subtilis in the artificial setting of the laboratory. To complement molecular genetic approaches, surface-associated communities in settings as diverse as the pitcher plant Sarracenia purpurea and the human lung were investigated. The study of the pitcher plant revealed that the presence or absence of a mosquito larva in the pitcher plant controlled bacterial diversity in the ecosystem inside the pitcher plant. Through the analysis of the respiratory tract microbiota of humans suffering from cystic fibrosis (CF) a correlation between lung function and bacterial community diversity was found. Those that had lungs in good condition had also more diverse communities, whereas patients harboring Pseudomonas aeruginosa-the predominant CF pathogen-in their lungs had less diverse communities. Further studies focused on interspecies and intraspecies relationships at the molecular level in search for signaling molecules that would promote biofilm formation. Two molecules were found that induced biofilm formation in B. subtilis: nystatin-released by other species-and surfactin-released by B. subtilis itself. This is a role not previously known for two molecules that were known for other activities-nystatin as an antifungal and surfactin as a surfactant. In addition, surfactin was found to also trigger cannibalism under starvation. This could be a strategy to maintain the population because the cells destroyed serve as nutrients for the rest. The path that led the author to the study of microbial biofilms is also described.

BioPAX – A community standard for pathway data sharing

PubMed Central

Demir, Emek; Cary, Michael P.; Paley, Suzanne; Fukuda, Ken; Lemer, Christian; Vastrik, Imre; Wu, Guanming; D’Eustachio, Peter; Schaefer, Carl; Luciano, Joanne; Schacherer, Frank; Martinez-Flores, Irma; Hu, Zhenjun; Jimenez-Jacinto, Veronica; Joshi-Tope, Geeta; Kandasamy, Kumaran; Lopez-Fuentes, Alejandra C.; Mi, Huaiyu; Pichler, Elgar; Rodchenkov, Igor; Splendiani, Andrea; Tkachev, Sasha; Zucker, Jeremy; Gopinath, Gopal; Rajasimha, Harsha; Ramakrishnan, Ranjani; Shah, Imran; Syed, Mustafa; Anwar, Nadia; Babur, Ozgun; Blinov, Michael; Brauner, Erik; Corwin, Dan; Donaldson, Sylva; Gibbons, Frank; Goldberg, Robert; Hornbeck, Peter; Luna, Augustin; Murray-Rust, Peter; Neumann, Eric; Reubenacker, Oliver; Samwald, Matthias; van Iersel, Martijn; Wimalaratne, Sarala; Allen, Keith; Braun, Burk; Whirl-Carrillo, Michelle; Dahlquist, Kam; Finney, Andrew; Gillespie, Marc; Glass, Elizabeth; Gong, Li; Haw, Robin; Honig, Michael; Hubaut, Olivier; Kane, David; Krupa, Shiva; Kutmon, Martina; Leonard, Julie; Marks, Debbie; Merberg, David; Petri, Victoria; Pico, Alex; Ravenscroft, Dean; Ren, Liya; Shah, Nigam; Sunshine, Margot; Tang, Rebecca; Whaley, Ryan; Letovksy, Stan; Buetow, Kenneth H.; Rzhetsky, Andrey; Schachter, Vincent; Sobral, Bruno S.; Dogrusoz, Ugur; McWeeney, Shannon; Aladjem, Mirit; Birney, Ewan; Collado-Vides, Julio; Goto, Susumu; Hucka, Michael; Le Novère, Nicolas; Maltsev, Natalia; Pandey, Akhilesh; Thomas, Paul; Wingender, Edgar; Karp, Peter D.; Sander, Chris; Bader, Gary D.

2010-01-01

BioPAX (Biological Pathway Exchange) is a standard language to represent biological pathways at the molecular and cellular level. Its major use is to facilitate the exchange of pathway data (http://www.biopax.org). Pathway data captures our understanding of biological processes, but its rapid growth necessitates development of databases and computational tools to aid interpretation. However, the current fragmentation of pathway information across many databases with incompatible formats presents barriers to its effective use. BioPAX solves this problem by making pathway data substantially easier to collect, index, interpret and share. BioPAX can represent metabolic and signaling pathways, molecular and genetic interactions and gene regulation networks. BioPAX was created through a community process. Through BioPAX, millions of interactions organized into thousands of pathways across many organisms, from a growing number of sources, are available. Thus, large amounts of pathway data are available in a computable form to support visualization, analysis and biological discovery. PMID:20829833

Microbial diversity and interactions in subgingival biofilm communities.

PubMed

Diaz, Patricia I

2012-01-01

The human subgingival environment is a complex environmental niche where microorganisms from the three domains of life meet to form diverse biofilm communities that exist in close proximity to the host. Bacteria constitute the most abundant, diverse and ultimately well-studied component of these communities with about 500 bacterial taxa reported to occur in this niche. Cultivation and molecular approaches are revealing the breadth and depth of subgingival biofilm diversity as part of an effort to understand the subgingival microbiome, the collection of microorganisms that inhabit the gingival crevices. Although these investigations are constructing a pretty detailed taxonomical census of subgingival microbial communities, including inter-subject and temporal variability in community structure, as well as differences according to periodontal health status, we are still at the front steps in terms of understanding community function. Clinical studies that evaluate community structure need to be coupled with biologically relevant models that allow evaluation of the ecological determinants of subgingival biofilm maturation. Functional characteristics of subgingival biofilm communities that still need to be clarified include main metabolic processes that support microbial communities, identification of keystone species, microbial interactions and signaling events that lead to community maturation and the relationship of different communities with the host. This manuscript presents a summary of our current understanding of subgingival microbial diversity and an overview of experimental models used to dissect the functional characteristics of subgingival communities. Future coupling of 'omics'-based approaches with such models will facilitate a better understanding of subgingival ecology opening opportunities for community manipulation. Copyright © 2012 S. Karger AG, Basel.

Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts.

PubMed

Palková, Zdena; Váchová, Libuše

2016-09-01

Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

General simulation algorithm for autocorrelated binary processes.

PubMed

Serinaldi, Francesco; Lombardo, Federico

2017-02-01

The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

E-Model for Online Learning Communities.

PubMed

Rogo, Ellen J; Portillo, Karen M

2015-10-01

The purpose of this study was to explore the students' perspectives on the phenomenon of online learning communities while enrolled in a graduate dental hygiene program. A qualitative case study method was designed to investigate the learners' experiences with communities in an online environment. A cross-sectional purposive sampling method was used. Interviews were the data collection method. As the original data were being analyzed, the researchers noted a pattern evolved indicating the phenomenon developed in stages. The data were re-analyzed and validated by 2 member checks. The participants' experiences revealed an e-model consisting of 3 stages of formal learning community development as core courses in the curriculum were completed and 1 stage related to transmuting the community to an informal entity as students experienced the independent coursework in the program. The development of the formal learning communities followed 3 stages: Building a Foundation for the Learning Community, Building a Supportive Network within the Learning Community and Investing in the Community to Enhance Learning. The last stage, Transforming the Learning Community, signaled a transition to an informal network of learners. The e-model was represented by 3 key elements: metamorphosis of relationships, metamorphosis through the affective domain and metamorphosis through the cognitive domain, with the most influential element being the affective development. The e-model describes a 4 stage process through which learners experience a metamorphosis in their affective, relationship and cognitive development. Synergistic learning was possible based on the interaction between synergistic relationships and affective actions. Copyright © 2015 The American Dental Hygienists’ Association.

Spatial correlation analysis of urban traffic state under a perspective of community detection

NASA Astrophysics Data System (ADS)

Yang, Yanfang; Cao, Jiandong; Qin, Yong; Jia, Limin; Dong, Honghui; Zhang, Aomuhan

2018-05-01

Understanding the spatial correlation of urban traffic state is essential for identifying the evolution patterns of urban traffic state. However, the distribution of traffic state always has characteristics of large spatial span and heterogeneity. This paper adapts the concept of community detection to the correlation network of urban traffic state and proposes a new perspective to identify the spatial correlation patterns of traffic state. In the proposed urban traffic network, the nodes represent road segments, and an edge between a pair of nodes is added depending on the result of significance test for the corresponding correlation of traffic state. Further, the process of community detection in the urban traffic network (named GWPA-K-means) is applied to analyze the spatial dependency of traffic state. The proposed method extends the traditional K-means algorithm in two steps: (i) redefines the initial cluster centers by two properties of nodes (the GWPA value and the minimum shortest path length); (ii) utilizes the weight signal propagation process to transfer the topological information of the urban traffic network into a node similarity matrix. Finally, numerical experiments are conducted on a simple network and a real urban road network in Beijing. The results show that GWPA-K-means algorithm is valid in spatial correlation analysis of traffic state. The network science and community structure analysis perform well in describing the spatial heterogeneity of traffic state on a large spatial scale.

MyD88 signaling in T cells directs IgA-mediated control of the microbiota to promote health

PubMed Central

Kubinak, Jason L.; Petersen, Charisse; Stephens, W. Zac; Soto, Ray; Bake, Erin; O’Connell, Ryan M.; Round, June L.

2015-01-01

SUMMARY Altered commensal communities are associated with human disease. IgA mediates intestinal homeostasis and regulates microbiota composition. Intestinal IgA is produced at high levels as a result of T follicular helper cell (TFH) and B cell interactions in germinal centers. However, the pathways directing host IgA responses towards the microbiota remain unknown. Here, we report that signaling through the innate adaptor MyD88 in gut T cells coordinates germinal center responses, including TFH and IgA+ B cell development. TFH development is deficient in germfree mice and can be restored by feeding TLR2 agonists that activate T cell intrinsic MyD88 signaling. Loss of this pathway diminishes high affinity IgA targeting of the microbiota and fails to control the bacterial community, leading to worsened disease. Our findings identify that T cells converge innate and adaptive immune signals to coordinate IgA against the microbiota, constraining microbial community membership to promote symbiosis. PMID:25620548

Decision support environment for medical product safety surveillance.

PubMed

Botsis, Taxiarchis; Jankosky, Christopher; Arya, Deepa; Kreimeyer, Kory; Foster, Matthew; Pandey, Abhishek; Wang, Wei; Zhang, Guangfan; Forshee, Richard; Goud, Ravi; Menschik, David; Walderhaug, Mark; Woo, Emily Jane; Scott, John

2016-12-01

We have developed a Decision Support Environment (DSE) for medical experts at the US Food and Drug Administration (FDA). The DSE contains two integrated systems: The Event-based Text-mining of Health Electronic Records (ETHER) and the Pattern-based and Advanced Network Analyzer for Clinical Evaluation and Assessment (PANACEA). These systems assist medical experts in reviewing reports submitted to the Vaccine Adverse Event Reporting System (VAERS) and the FDA Adverse Event Reporting System (FAERS). In this manuscript, we describe the DSE architecture and key functionalities, and examine its potential contributions to the signal management process by focusing on four use cases: the identification of missing cases from a case series, the identification of duplicate case reports, retrieving cases for a case series analysis, and community detection for signal identification and characterization. Published by Elsevier Inc.

Seasonal changes in predator community switch the direction of selection for prey defences

PubMed Central

Mappes, Johanna; Kokko, Hanna; Ojala, Katja; Lindström, Leena

2014-01-01

Insect communities consist of aposematic species with efficient warning colours against predation, as well as abundant examples of crypsis. To understand such coexistence, we here report results from a field experiment where relative survival of artificial larvae, varying in conspicuousness, was estimated in natural bird communities over an entire season. This takes advantage of natural variation in the proportion of naive predators: naivety peaks when young birds have just fledged. We show that the relative benefit of warning signals and crypsis changes accordingly. When naive birds are rare (early and late in the season), conspicuous warning signals improve survival, but conspicuousness becomes a disadvantage near the fledging time of birds. Such temporal structuring of predator–prey relationships facilitates the coexistence of diverse antipredatory strategies and helps explain two patterns we found in a 688-species community of Lepidoterans: larval warning signals remain rare and occur disproportionately often in seasons when predators are educated. PMID:25247589

Engineering microbial consortia to enhance biomining and bioremediation.

PubMed

Brune, Karl D; Bayer, Travis S

2012-01-01

In natural environments microorganisms commonly exist as communities of multiple species that are capable of performing more varied and complicated tasks than clonal populations. Synthetic biologists have engineered clonal populations with characteristics such as differentiation, memory, and pattern formation, which are usually associated with more complex multicellular organisms. The prospect of designing microbial communities has alluring possibilities for environmental, biomedical, and energy applications, and is likely to reveal insight into how natural microbial consortia function. Cell signaling and communication pathways between different species are likely to be key processes for designing novel functions in synthetic and natural consortia. Recent efforts to engineer synthetic microbial interactions will be reviewed here, with particular emphasis given to research with significance for industrial applications in the field of biomining and bioremediation of acid mine drainage.

Engineering microbial consortia to enhance biomining and bioremediation

PubMed Central

Brune, Karl D.; Bayer, Travis S.

2012-01-01

In natural environments microorganisms commonly exist as communities of multiple species that are capable of performing more varied and complicated tasks than clonal populations. Synthetic biologists have engineered clonal populations with characteristics such as differentiation, memory, and pattern formation, which are usually associated with more complex multicellular organisms. The prospect of designing microbial communities has alluring possibilities for environmental, biomedical, and energy applications, and is likely to reveal insight into how natural microbial consortia function. Cell signaling and communication pathways between different species are likely to be key processes for designing novel functions in synthetic and natural consortia. Recent efforts to engineer synthetic microbial interactions will be reviewed here, with particular emphasis given to research with significance for industrial applications in the field of biomining and bioremediation of acid mine drainage. PMID:22679443

An algorithm for modularization of MAPK and calcium signaling pathways: comparative analysis among different species.

PubMed

Nayak, Losiana; De, Rajat K

2007-12-01

Signaling pathways are large complex biochemical networks. It is difficult to analyze the underlying mechanism of such networks as a whole. In the present article, we have proposed an algorithm for modularization of signal transduction pathways. Unlike studying a signaling pathway as a whole, this enables one to study the individual modules (less complex smaller units) easily and hence to study the entire pathway better. A comparative study of modules belonging to different species (for the same signaling pathway) has been made, which gives an overall idea about development of the signaling pathways over the taken set of species of calcium and MAPK signaling pathways. The superior performance, in terms of biological significance, of the proposed algorithm over an existing community finding algorithm of Newman [Newman MEJ. Modularity and community structure in networks. Proc Natl Acad Sci USA 2006;103(23):8577-82] has been demonstrated using the aforesaid pathways of H. sapiens.

Characteristics of official and experimental GRACE time series by GFZ and CSR - with applications to polar signals

NASA Astrophysics Data System (ADS)

Horvath, Alexander; Horwath, Martin; Pail, Roland

2014-05-01

The Release-05 monthly solutions by the three centers of the GRACE Science and Data System are a significant improvement with respect to the previous Release 4. Meanwhile, previous assessments have revealed different noise levels between the solutions by CSR, GFZ and JPL, and also different amplitudes of interannual signal in the solutions by GFZ as compared to the two other centers. Encouraged by the science community, GFZ and CSR have kindly provided additional sets of time series. GFZ has reprocessed the RL05 monthly solutions (up to degree and order 90) with revised processing. CSR has made available monthly solutions with standard processing up to degree and order 96, in addition to their solutions up to degree and order 60. We compare these different time series with respect to their signal and noise content and analyze them on global and regional scale. For the regional scale our special interest is paid on Antarctica and on revealing polar signals such as ice mass trends and GIA. Following the necessity of destriping, an optimal choice for the setup of the Swenson & Wahr filter approach is evaluated to adapt to the specific signal and noise level in Antarctica. Furthermore we analyze the potential benefit of mixed time series solutions in order to combine the strengths of the solutions available. Concerning the question for an optimal maximum degree we suggest that for resolving large polar ice mass changes, it would be beneficial to provide gravity field variations even beyond degree 90.

Validating of Atmospheric Signals Associated with some of the Major Earthquakes in Asia (2003-2009)

NASA Technical Reports Server (NTRS)

Ouzounov, D. P.; Pulinets, S.; Liu, J. Y.; Hattori, K.; Oarritm N,; Taylor, P. T.

2010-01-01

The recent catastrophic earthquake in Haiti (January 2010) has provided and renewed interest in the important question of the existence of precursory signals related to strong earthquakes. Latest studies (VESTO workshop in Japan 2009) have shown that there were precursory atmospheric signals observed on the ground and in space associated with several recent earthquakes. The major question, still widely debated in the scientific community is whether such signals systematically precede major earthquakes. To address this problem we have started to validate the anomalous atmospheric signals during the occurrence of large earthquakes. Our approach is based on integration analysis of several physical and environmental parameters (thermal infrared radiation, electron concentration in the ionosphere, Radon/ion activities, air temperature and seismicity) that were found to be associated with earthquakes. We performed hind-cast detection over three different regions with high seismicity Taiwan, Japan and Kamchatka for the period of 2003-2009. We are using existing thermal satellite data (Aqua and POES); in situ atmospheric data (NOAA/NCEP); and ionospheric variability data (GPS/TEC and DEMETER). The first part of this validation included 42 major earthquakes (M greater than 5.9): 10 events in Taiwan, 15 events in Japan, 15 events in Kamchatka and four most recent events for M8.0 Wenchuan earthquake (May 2008) in China and M7.9 Samoa earthquakes (Sep 2009). Our initial results suggest a systematic appearance of atmospheric anomalies near the epicentral area, 1 to 5 days prior to the largest earthquakes, that could be explained by a coupling process between the observed physical parameters, and the earthquake preparation processes.

Transcriptome analysis supports viral infection and fluoride toxicity as contributors to chronic kidney disease of unknown etiology (CKDu) in Sri Lanka.

PubMed

Sayanthooran, Saravanabavan; Gunerathne, Lishanthe; Abeysekera, Tilak D J; Magana-Arachchi, Dhammika N

2018-05-28

Chronic kidney disease of unknown etiology (CKDu), having epidemic characteristics, is being diagnosed increasingly in certain tropical regions of the world, mainly Latin America and Sri Lanka. They have been observed primarily in farming communities and current hypotheses point toward many environmental and occupational triggers. CKDu does not have common etiologies of chronic kidney disease (CKD) such as hypertension, diabetes, or autoimmune disease. We aimed to understand the molecular processes underlying CKDu in Sri Lanka using transcriptome analysis. RNA extracted from whole blood was reverse transcribed and used for microarray analysis using the Human HT-12 v.4 array (Illumina). Pathway analysis was carried out using ingenuity pathway analysis (IPA-Qiagen). Microarray results were validated using real-time PCR of five selected genes. Pathways related to innate immune response, including interferon signaling, inflammasome signaling and TREM1 signaling had the most significant positive activation z scores, where as EIF2 signaling and mTOR signaling had the most significant negative activation z scores. Pathways previously linked to fluoride toxicity; G-protein activation, Cdc42 signaling, Rac signaling and RhoA signaling were activated in CKDu patients. The most significantly activated biological functions were cell death, cell movement and antimicrobial response. Significant toxicological functions were mitochondrial dysfunction, oxidative stress and apoptosis. Based on the molecular pathway analysis in CKDu patients and review of literature, viral infections and fluoride toxicity appear to be contributing to the molecular mechanisms underlying CKDu.

Fungal Community Shifts in Structure and Function across a Boreal Forest Fire Chronosequence

PubMed Central

Santalahti, Minna; Pumpanen, Jukka; Köster, Kajar; Berninger, Frank; Raffaello, Tommaso; Jumpponen, Ari; Asiegbu, Fred O.; Heinonsalo, Jussi

2015-01-01

Forest fires are a common natural disturbance in forested ecosystems and have a large impact on the microbial communities in forest soils. The response of soil fungal communities to forest fire is poorly documented. Here, we investigated fungal community structure and function across a 152-year boreal forest fire chronosequence using high-throughput sequencing of the internal transcribed spacer 2 (ITS2) region and a functional gene array (GeoChip). Our results demonstrate that the boreal forest soil fungal community was most diverse soon after a fire disturbance and declined over time. The differences in the fungal communities were explained by changes in the abundance of basidiomycetes and ascomycetes. Ectomycorrhizal (ECM) fungi contributed to the increase in basidiomycete abundance over time, with the operational taxonomic units (OTUs) representing the genera Cortinarius and Piloderma dominating in abundance. Hierarchical cluster analysis by using gene signal intensity revealed that the sites with different fire histories formed separate clusters, suggesting differences in the potential to maintain essential biogeochemical soil processes. The site with the greatest biological diversity had also the most diverse genes. The genes involved in organic matter degradation in the mature forest, in which ECM fungi were the most abundant, were as common in the youngest site, in which saprotrophic fungi had a relatively higher abundance. This study provides insight into the impact of fire disturbance on soil fungal community dynamics. PMID:26341215

A review on the applications of microbial electrolysis cells in anaerobic digestion.

PubMed

Yu, Zhengsheng; Leng, Xiaoyun; Zhao, Shuai; Ji, Jing; Zhou, Tuoyu; Khan, Aman; Kakde, Apurva; Liu, Pu; Li, Xiangkai

2018-05-01

Anaerobic digestion (AD) has been widely used for biogas or biofuel generation from waste treatment. Because a low production rate and instability of AD occur frequently, various technologies have been applied to improvement of AD. Microbial electrolysis cells (MECs), an emerging technology, can convert organic matter into hydrogen, methane, and other value-added products. Recent studies showed that application of MEC to AD (MEC-AD) can accelerate degradation of a substrate (including recalcitrant compounds) and alter AD microbial community by enriching exoelectrogens and methanogens thus increasing biogas production. With stable microbial communities established, improvement of MEC-AD for methane production was achieved. MEC-AD process can be monitored in real-time by detecting electric signals, which linearly correlate with substrate concentrations. This review attempts to evaluate interactions among the decomposition of substrates, MEC-AD system, and the microbial community. This analysis should provide useful insights into the improvement of methane production and the performance of MEC-AD. Copyright © 2018 Elsevier Ltd. All rights reserved.

Orbit and clock determination of BDS regional navigation satellite system based on IGS M-GEX and WHU BETS tracking network

NASA Astrophysics Data System (ADS)

GENG, T.; Zhao, Q.; Shi, C.; Shum, C.; Guo, J.; Su, X.

2013-12-01

BeiDou Navigation Satellite System (BDS) began to provide the regional open service on December 27th 2012 and will provide the global open service by the end of 2020. Compared to GPS, the space segment of BDS Regional System consists of 5 Geostationary Earth Orbit satellites (GEO), 5 Inclined Geosynchronous Orbit satellites (IGSO) and 4 Medium Earth orbit (MEO) satellites. Since 2011, IGS Multiple-GNSS Experiment (M-GEX) focuses on tracking the newly available GNSS signals. This includes all signals from the modernized satellites of the GPS and GLONASS systems, as well as signals of the BDS, Galileo and QZSS systems. Up to now, BDS satellites are tracked by around 25 stations with a variety of different antennas and receivers from different GNSS manufacture communities in M-GEX network. Meanwhile, there are 17 stations with Unicore Communications Incorporation's GPS/BDS receivers in BeiDou Experimental Tracking Stations (BETS) network by Wuhan University. In addition, 5 BDS satellites have been tracking by the International Laser Ranging Service (ILRS). BDS performance is expected to be further studied by the GNSS communities. Following an introduction of the BDS system and above different tracking network, this paper discusses the achieved BDS characterization and performance assessment. Firstly, the BDS signal and measurement quality are analyzed with different antennas and receivers in detail compared to GPS. This includes depth of coverage for satellite observation, carrier-to-noise-density ratios, code noise and multipath, carrier phase errors. Secondly, BDS Precise Orbit Determination (POD) is processed. Different arc lengths and sets of orbit parameters are tested using Position And Navigation Data Analysis software (PANDA) which is developed at the Wuhan University. GEO, IGSO and MEO satellites orbit quality will be assessed using overlap comparison, 2-day orbit fit and external validations with Satellite Laser Range (SLR). Then BDS satellites are equipped with Rubidium clocks and clocks performance are also presented. Finally, benefits of BDS processing strategies and further developments are concluded.

Optical field encryption for secure transmission of data

NASA Astrophysics Data System (ADS)

Fraser, Colin B.; Harvey, Andrew R.

2004-12-01

The growing awareness of the vulnerability of information transmitted on communication systems within the government, military and commercial sectors, has stimulated a number of areas of research within the optical community to design optical hardware encryption systems providing inherent immunity to espionage techniques. This paper describes a hardware optical encryption technique that utilises off the shelf telecommunication equipment and negates the necessity for an independent key distribution system with respect to the data transmission system, as is common with alternative encryption system implementations. This method also lends itself easily to fiber optic or free space communication and is applicable within any optical waveband. The encryption-decryption of the optical signal is achieved through low coherence optical interferometry. This requires the instantaneous processing and analysis of the signal, optically, to retrieve the relevant optical phase information hidden in the transmitted optical noise. This technology allows an authorised user to transmit encrypted information at a high data rate securely, while maintaining opaqueness to an unauthorised observer that data transmission is occurring. As the instantaneous optical field properties of the signals present in the system are essential to the optical encryption - decryption process, the system is inherently protected against electronic recording and advances in computational decryption algorithms. For organisations wishing to protect sensitive data and levels of communication activity these are highly desirable features.

Molecular locks and keys: the role of small molecules in phytohormone research

PubMed Central

Fonseca, Sandra; Rosado, Abel; Vaughan-Hirsch, John; Bishopp, Anthony; Chini, Andrea

2014-01-01

Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signaling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signaling networks. By its nature, phytohormone research lies at the interface between chemistry and biology. Classically, the scientific community has always used synthetic phytohormones and analogs to study hormone functions and responses. However, recent advances in synthetic and combinational chemistry, have allowed a new field, plant chemical biology, to emerge and this has provided a powerful tool with which to study phytohormone function. Plant chemical biology is helping to address some of the most enduring questions in phytohormone research such as: Are there still undiscovered plant hormones? How can we identify novel signaling molecules? How can plants activate specific hormone responses in a tissue-specific manner? How can we modulate hormone responses in one developmental context without inducing detrimental effects on other processes? The chemical genomics approaches rely on the identification of small molecules modulating different biological processes and have recently identified active forms of plant hormones and molecules regulating many aspects of hormone synthesis, transport and response. We envision that the field of chemical genomics will continue to provide novel molecules able to elucidate specific aspects of hormone-mediated mechanisms. In addition, compounds blocking specific responses could uncover how complex biological responses are regulated. As we gain information about such compounds we can design small alterations to the chemical structure to further alter specificity, enhance affinity or modulate the activity of these compounds. PMID:25566283

On the distortion of elevation dependent warming signals by quantile mapping

NASA Astrophysics Data System (ADS)

Jury, Martin W.; Mendlik, Thomas; Maraun, Douglas

2017-04-01

Elevation dependent warming (EDW), the amplification of warming under climate change with elevation, is likely to accelerate changes in e.g. cryospheric and hydrological systems. Responsible for EDW is a mixture of processes including snow albedo feedback, cloud formations or the location of aerosols. The degree of incorporation of this processes varies across state of the art climate models. In a recent study we were preparing bias corrected model output of CMIP5 GCMs and CORDEX RCMs over the Himalayan region for the glacier modelling community. In a first attempt we used quantile mapping (QM) to generate this data. A beforehand model evaluation showed that more than two third of the 49 included climate models were able to reproduce positive trend differences between areas of higher and lower elevations in winter, clearly visible in all of our five observational datasets used. Regrettably, we noticed that height dependent trend signals provided by models were distorted, most of the time in the direction of less EDW, sometimes even reversing EDW signals present in the models before the bias correction. As a consequence, we refrained from using quantile mapping for our task, as EDW poses one important factor influencing the climate in high altitudes for the nearer and more distant future, and used a climate change signal preserving bias correction approach. Here we present our findings of the distortion of the EDW temperature change by QM and discuss the influence of QM on different statistical properties as well as their modifications.

Warning signals are under positive frequency-dependent selection in nature

PubMed Central

Chouteau, Mathieu; Arias, Mónica; Joron, Mathieu

2016-01-01

Positive frequency-dependent selection (FDS) is a selection regime where the fitness of a phenotype increases with its frequency, and it is thought to underlie important adaptive strategies resting on signaling and communication. However, whether and how positive FDS truly operates in nature remains unknown, which hampers our understanding of signal diversity. Here, we test for positive FDS operating on the warning color patterns of chemically defended butterflies forming multiple coexisting mimicry assemblages in the Amazon. Using malleable prey models placed in localities showing differences in the relative frequencies of warningly colored prey, we demonstrate that the efficiency of a warning signal increases steadily with its local frequency in the natural community, up to a threshold where protection stabilizes. The shape of this relationship is consistent with the direct effect of the local abundance of each warning signal on the corresponding avoidance knowledge of the local predator community. This relationship, which differs from purifying selection acting on each mimetic pattern, indicates that predator knowledge, integrated over the entire community, is saturated only for the most common warning signals. In contrast, among the well-established warning signals present in local prey assemblages, most are incompletely known to local predators and enjoy incomplete protection. This incomplete predator knowledge should generate strong benefits to life history traits that enhance warning efficiency by increasing the effective frequency of prey visible to predators. Strategies such as gregariousness or niche convergence between comimics may therefore readily evolve through their effects on predator knowledge and warning efficiency. PMID:26858416

Bacterial communities in pigmented biofilms formed on the sandstone bas-relief walls of the Bayon Temple, Angkor Thom, Cambodia.

PubMed

Kusumi, Asako; Li, Xianshu; Osuga, Yu; Kawashima, Arata; Gu, Ji-Dong; Nasu, Masao; Katayama, Yoko

2013-01-01

The Bayon temple in Angkor Thom, Cambodia has shown serious deterioration and is subject to the formation of various pigmented biofilms. Because biofilms are damaging the bas-reliefs, low reliefs engraved on the surface of sandstone, information about the microbial community within them is indispensable to control biofilm colonization. PCR-denaturing gradient gel electrophoresis (DGGE) analysis of biofilm samples from the pigmented sandstone surfaces showed that the bacterial community members in the biofilms differed clearly from those in the air and had low sequence similarity to database sequences. Non-destructive sampling of biofilm revealed novel bacterial groups of predominantly Rubrobacter in salmon pink biofilm, Cyanobacteria in chrome green biofilm, Cyanobacteria and Chloroflexi in signal violet biofilm, Chloroflexi in black gray biofilm, and Deinococcus-Thermus, Cyanobacteria, and Rubrobacter in blue green biofilm. Serial peeling-off of a thick biofilm by layers with adhesive sheets revealed a stratified structure: the blue-green biofilm, around which there was serious deterioration, was very rich in Cyanobacteria near the surface and Chloroflexi in deep layer below. Nitrate ion concentrations were high in the blue-green biofilm. The characteristic distribution of bacteria at different biofilm depths provides valuable information on not only the biofilm formation process but also the sandstone weathering process in the tropics.

Spatially-dependent alkyl quinolone signaling responses to antibiotics in Pseudomonas aeruginosa swarms.

PubMed

Morales-Soto, Nydia; Dunham, Sage J B; Baig, Nameera F; Ellis, Joseph F; Madukoma, Chinedu S; Bohn, Paul W; Sweedler, Jonathan V; Shrout, Joshua D

2018-03-27

There is a general lack of understanding about how communities of bacteria respond to exogenous toxins such as antibiotics. Most of our understanding of community-level stress responses comes from the study of stationary biofilm communities. Although several community behaviors and production of specific biomolecules affecting biofilm development and associated behavior have been described for Pseudomonas aeruginosa and other bacteria, we have little appreciation for the production and dispersal of secreted metabolites within the 2D and 3D spaces they occupy as they colonize, spread, and grow on surfaces. Here we specifically studied the phenotypic responses and spatial variability of alkyl quinolones, including the Pseudomonas quinolone signal (PQS) and members of the alkyl hydroxyquinoline (AQNO) subclass, in P. aeruginosa plate-assay swarming communities. We found that PQS production was not a universal signaling response to antibiotics as tobramycin elicited an alkyl quinolone response while carbenicillin did not. We also found that PQS and AQNO profiles in response to tobramycin were markedly distinct and influenced these swarms on different spatial scales. The distribution of alkyl quinolones varied by several orders of magnitude within the same swarm. At some tobramycin exposures, P. aeruginosa swarms produced alkyl quinolones in the range of 150 µM PQS and 400 µM AQNO that accumulated as aggregates. Our collective findings show that the distribution of alkyl quinolones can vary by several orders of magnitude within the same swarming community.  More notably, our results suggest that multiple intercellular signals acting on different spatial scales can be triggered by one common cue. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Alternative measures of spatial distribution and availability of health facilities for the delivery of emergency obstetric services in island communities.

PubMed

Oyerinde, Koyejo; Baravilala, Wame

2014-12-01

International guidelines and recommendations for availability and spatial distribution of emergency obstetric care services do not adequately address the challenges of providing emergency health services in island communities. The isolation and small population sizes that are typical of islands and remote populations limit the applicability of international guidelines in such communities. Universal access to emergency obstetric care services, when pregnant women encounter complications, is one of the three key strategies for reducing maternal and newborn mortality; the other two being family planning and skilled care during labor. The performance of selected lifesaving clinical interventions (signal functions) over a 3-month period is commonly used to assess and assign performance categories to health facilities but island communities might not have a large enough population to generate demand for all the signal functions over a 3-month period. Similarly, availability and spatial distribution recommendations are typically based on the size of catchment populations, but the populations of island communities tend to be sparsely distributed. With illustrations from six South Pacific Island states, we argue that the recommendation for availability of health facilities, that there should be at least five emergency obstetric care facilities (including at least one comprehensive facility) for every 500,000 population, and the recommendation for equitable distribution of health facilities, that all subnational areas meet the availability recommendation, can be substituted with a focus on access to blood transfusion and obstetric surgical care within 2 hours for all pregnant residents of islands. Island communities could replace the performance of signal functions over a 3-month period with a demonstrated capacity to perform signal functions if the need arises.

Extracellular signals that define distinct and coexisting cell fates in Bacillus subtilis.

PubMed

López, Daniel; Kolter, Roberto

2010-03-01

The soil-dwelling bacterium Bacillus subtilis differentiates into distinct subpopulations of specialized cells that coexist within highly structured communities. The coordination and interplay between these cell types requires extensive extracellular communication driven mostly by sensing self-generated secreted signals. These extracellular signals activate a set of sensor kinases, which respond by phosphorylating three major regulatory proteins, Spo0A, DegU and ComA. Each phosphorylated regulator triggers a specific differentiation program while at the same time repressing other differentiation programs. This allows a cell to differentiate in response to a specific cue, even in the presence of other, possibly conflicting, signals. The sensor kinases involved respond to an eclectic group of extracellular signals, such as quorum-sensing molecules, natural products, temperature, pH or scarcity of nutrients. This article reviews the cascades of cell differentiation pathways that are triggered by sensing extracellular signals. We also present a tentative developmental model in which the diverse cell types sequentially differentiate to achieve the proper development of the bacterial community.

Deep Sequencing of the Medicago truncatula Root Transcriptome Reveals a Massive and Early Interaction between Nodulation Factor and Ethylene Signals.

PubMed

Larrainzar, Estíbaliz; Riely, Brendan K; Kim, Sang Cheol; Carrasquilla-Garcia, Noelia; Yu, Hee-Ju; Hwang, Hyun-Ju; Oh, Mijin; Kim, Goon Bo; Surendrarao, Anandkumar K; Chasman, Deborah; Siahpirani, Alireza F; Penmetsa, Ramachandra V; Lee, Gang-Seob; Kim, Namshin; Roy, Sushmita; Mun, Jeong-Hwan; Cook, Douglas R

2015-09-01

The legume-rhizobium symbiosis is initiated through the activation of the Nodulation (Nod) factor-signaling cascade, leading to a rapid reprogramming of host cell developmental pathways. In this work, we combine transcriptome sequencing with molecular genetics and network analysis to quantify and categorize the transcriptional changes occurring in roots of Medicago truncatula from minutes to days after inoculation with Sinorhizobium medicae. To identify the nature of the inductive and regulatory cues, we employed mutants with absent or decreased Nod factor sensitivities (i.e. Nodulation factor perception and Lysine motif domain-containing receptor-like kinase3, respectively) and an ethylene (ET)-insensitive, Nod factor-hypersensitive mutant (sickle). This unique data set encompasses nine time points, allowing observation of the symbiotic regulation of diverse biological processes with high temporal resolution. Among the many outputs of the study is the early Nod factor-induced, ET-regulated expression of ET signaling and biosynthesis genes. Coupled with the observation of massive transcriptional derepression in the ET-insensitive background, these results suggest that Nod factor signaling activates ET production to attenuate its own signal. Promoter:β-glucuronidase fusions report ET biosynthesis both in root hairs responding to rhizobium as well as in meristematic tissue during nodule organogenesis and growth, indicating that ET signaling functions at multiple developmental stages during symbiosis. In addition, we identified thousands of novel candidate genes undergoing Nod factor-dependent, ET-regulated expression. We leveraged the power of this large data set to model Nod factor- and ET-regulated signaling networks using MERLIN, a regulatory network inference algorithm. These analyses predict key nodes regulating the biological process impacted by Nod factor perception. We have made these results available to the research community through a searchable online resource. © 2015 American Society of Plant Biologists. All Rights Reserved.

Effect of copper treatment on the composition and function of the bacterial community in the sponge Haliclona cymaeformis.

PubMed

Tian, Ren-Mao; Wang, Yong; Bougouffa, Salim; Gao, Zhao-Ming; Cai, Lin; Zhang, Wei-Peng; Bajic, Vladimir; Qian, Pei-Yuan

2014-11-04

Marine sponges are the most primitive metazoan and host symbiotic microorganisms. They are crucial components of the marine ecological system and play an essential role in pelagic processes. Copper pollution is currently a widespread problem and poses a threat to marine organisms. Here, we examined the effects of copper treatment on the composition of the sponge-associated bacterial community and the genetic features that facilitate the survival of enriched bacteria under copper stress. The 16S rRNA gene sequencing results showed that the sponge Haliclona cymaeformis harbored symbiotic sulfur-oxidizing Ectothiorhodospiraceae and photosynthetic Cyanobacteria as dominant species. However, these autotrophic bacteria decreased substantially after treatment with a high copper concentration, which enriched for a heterotrophic-bacterium-dominated community. Metagenomic comparison revealed a varied profile of functional genes and enriched functions, including bacterial motility and chemotaxis, extracellular polysaccharide and capsule synthesis, virulence-associated genes, and genes involved in cell signaling and regulation, suggesting short-period mechanisms of the enriched bacterial community for surviving copper stress in the microenvironment of the sponge. Microscopic observation and comparison revealed dynamic bacterial aggregation within the matrix and lysis of sponge cells. The bacteriophage community was also enriched, and the complete genome of a dominant phage was determined, implying that a lytic phage cycle was stimulated by the high copper concentration. This study demonstrated a copper-induced shift in the composition of functional genes of the sponge-associated bacterial community, revealing the selective effect of copper treatment on the functions of the bacterial community in the microenvironment of the sponge. This study determined the bacterial community structure of the common sponge Haliclona cymaeformis and examined the effect of copper treatment on the community structure and functional gene composition, revealing that copper treatment had a selective effect on the functions of the bacterial community in the sponge. These findings suggest that copper pollution has an ecological impact on the sponge symbiont. The analysis showed that the untreated sponges hosted symbiotic autotrophic bacteria as dominant species, and the high-concentration copper treatment enriched for a heterotrophic bacterial community with enrichment for genes important for bacterial motility, supplementary cellular components, signaling and regulation, and virulence. Microscopic observation showed obvious bacterial aggregation and a reduction of sponge cell numbers in treated sponges, which suggested the formation of aggregates to reduce the copper concentration. The enrichment for functions of directional bacterial movement and supplementary cellular components and the formation of bacterial aggregates and phage enrichment are novel findings in sponge studies. Copyright © 2014 Tian et al.

Information transmission in microbial and fungal communication: from classical to quantum.

PubMed

Majumdar, Sarangam; Pal, Sukla

2018-06-01

Microbes have their own communication systems. Secretion and reception of chemical signaling molecules and ion-channels mediated electrical signaling mechanism are yet observed two special ways of information transmission in microbial community. In this article, we address the aspects of various crucial machineries which set the backbone of microbial cell-to-cell communication process such as quorum sensing mechanism (bacterial and fungal), quorum sensing regulated biofilm formation, gene expression, virulence, swarming, quorum quenching, role of noise in quorum sensing, mathematical models (therapy model, evolutionary model, molecular mechanism model and many more), synthetic bacterial communication, bacterial ion-channels, bacterial nanowires and electrical communication. In particular, we highlight bacterial collective behavior with classical and quantum mechanical approaches (including quantum information). Moreover, we shed a new light to introduce the concept of quantum synthetic biology and possible cellular quantum Turing test.

ObsPy: A Python Toolbox for Seismology - Recent Developments and Applications

NASA Astrophysics Data System (ADS)

Megies, T.; Krischer, L.; Barsch, R.; Sales de Andrade, E.; Beyreuther, M.

2014-12-01

ObsPy (http://www.obspy.org) is a community-driven, open-source project dedicated to building a bridge for seismology into the scientific Python ecosystem. It offersa) read and write support for essentially all commonly used waveform, station, and event metadata file formats with a unified interface,b) a comprehensive signal processing toolbox tuned to the needs of seismologists,c) integrated access to all large data centers, web services and databases, andd) convenient wrappers to legacy codes like libtau and evalresp.Python, currently the most popular language for teaching introductory computer science courses at top-ranked U.S. departments, is a full-blown programming language with the flexibility of an interactive scripting language. Its extensive standard library and large variety of freely available high quality scientific modules cover most needs in developing scientific processing workflows. Together with packages like NumPy, SciPy, Matplotlib, IPython, Pandas, lxml, and PyQt, ObsPy enables the construction of complete workflows in Python. These vary from reading locally stored data or requesting data from one or more different data centers through to signal analysis and data processing and on to visualizations in GUI and web applications, output of modified/derived data and the creation of publication-quality figures.ObsPy enjoys a large world-wide rate of adoption in the community. Applications successfully using it include time-dependent and rotational seismology, big data processing, event relocations, and synthetic studies about attenuation kernels and full-waveform inversions to name a few examples. All functionality is extensively documented and the ObsPy tutorial and gallery give a good impression of the wide range of possible use cases.We will present the basic features of ObsPy, new developments and applications, and a roadmap for the near future and discuss the sustainability of our open-source development model.

Bacterial community structure transformed after thermophilically composting human waste in Haiti

PubMed Central

Kramer, Sasha; Roy, Monika; Reid, Francine C.; Dubinsky, Eric A.

2017-01-01

Recycling human waste for beneficial use has been practiced for millennia. Aerobic (thermophilic) composting of sewage sludge has been shown to reduce populations of opportunistically pathogenic bacteria and to inactivate both Ascaris eggs and culturable Escherichia coli in raw waste, but there is still a question about the fate of most fecal bacteria when raw material is composted directly. This study undertook a comprehensive microbial community analysis of composting material at various stages collected over 6 months at two composting facilities in Haiti. The fecal microbiota signal was monitored using a high-density DNA microarray (PhyloChip). Thermophilic composting altered the bacterial community structure of the starting material. Typical fecal bacteria classified in the following groups were present in at least half the starting material samples, yet were reduced below detection in finished compost: Prevotella and Erysipelotrichaceae (100% reduction of initial presence), Ruminococcaceae (98–99%), Lachnospiraceae (83–94%, primarily unclassified taxa remained), Escherichia and Shigella (100%). Opportunistic pathogens were reduced below the level of detection in the final product with the exception of Clostridium tetani, which could have survived in a spore state or been reintroduced late in the outdoor maturation process. Conversely, thermotolerant or thermophilic Actinomycetes and Firmicutes (e.g., Thermobifida, Bacillus, Geobacillus) typically found in compost increased substantially during the thermophilic stage. This community DNA-based assessment of the fate of human fecal microbiota during thermophilic composting will help optimize this process as a sanitation solution in areas where infrastructure and resources are limited. PMID:28570610

Expressive facial animation synthesis by learning speech coarticulation and expression spaces.

PubMed

Deng, Zhigang; Neumann, Ulrich; Lewis, J P; Kim, Tae-Yong; Bulut, Murtaza; Narayanan, Shrikanth

2006-01-01

Synthesizing expressive facial animation is a very challenging topic within the graphics community. In this paper, we present an expressive facial animation synthesis system enabled by automated learning from facial motion capture data. Accurate 3D motions of the markers on the face of a human subject are captured while he/she recites a predesigned corpus, with specific spoken and visual expressions. We present a novel motion capture mining technique that "learns" speech coarticulation models for diphones and triphones from the recorded data. A Phoneme-Independent Expression Eigenspace (PIEES) that encloses the dynamic expression signals is constructed by motion signal processing (phoneme-based time-warping and subtraction) and Principal Component Analysis (PCA) reduction. New expressive facial animations are synthesized as follows: First, the learned coarticulation models are concatenated to synthesize neutral visual speech according to novel speech input, then a texture-synthesis-based approach is used to generate a novel dynamic expression signal from the PIEES model, and finally the synthesized expression signal is blended with the synthesized neutral visual speech to create the final expressive facial animation. Our experiments demonstrate that the system can effectively synthesize realistic expressive facial animation.

Non-stationary signal analysis based on general parameterized time-frequency transform and its application in the feature extraction of a rotary machine

NASA Astrophysics Data System (ADS)

Zhou, Peng; Peng, Zhike; Chen, Shiqian; Yang, Yang; Zhang, Wenming

2018-06-01

With the development of large rotary machines for faster and more integrated performance, the condition monitoring and fault diagnosis for them are becoming more challenging. Since the time-frequency (TF) pattern of the vibration signal from the rotary machine often contains condition information and fault feature, the methods based on TF analysis have been widely-used to solve these two problems in the industrial community. This article introduces an effective non-stationary signal analysis method based on the general parameterized time-frequency transform (GPTFT). The GPTFT is achieved by inserting a rotation operator and a shift operator in the short-time Fourier transform. This method can produce a high-concentrated TF pattern with a general kernel. A multi-component instantaneous frequency (IF) extraction method is proposed based on it. The estimation for the IF of every component is accomplished by defining a spectrum concentration index (SCI). Moreover, such an IF estimation process is iteratively operated until all the components are extracted. The tests on three simulation examples and a real vibration signal demonstrate the effectiveness and superiority of our method.

More closely related plants have more distinct mycorrhizal communities

USDA-ARS?s Scientific Manuscript database

1. Neighboring plants are known to vary from having similar to dissimilar arbuscular mycorrhizal fungal (AMF) communities. One possibility is that closely related plants have more similar AMF communities than more distantly related plants, an indication of phylogenetic signal in host use. Here, we...

Floral colour versus phylogeny in structuring subalpine flowering communities.

PubMed

McEwen, Jamie R; Vamosi, Jana C

2010-10-07

The relative number of seeds produced by competing species can influence the community structure; yet, traits that influence seed production, such as pollinator attraction and floral colour, have received little attention in community ecology. Here, we analyse floral colour using reflectance spectra that include near-UV and examined the phylogenetic signal of floral colour. We found that coflowering species within communities tended to be more divergent in floral colour than expected by chance. However, coflowering species were not phylogenetically dispersed, in part due to our finding that floral colour is a labile trait with a weak phylogenetic signal. Furthermore, while we found that locally rare and common species exhibited equivalent floral colour distances from their coflowering neighbours, frequent species (those found in more communities) exhibited higher colour distances from their coflowering neighbours. Our findings support recent studies, which have found that (i) plant lineages exhibit frequent floral colour transitions; and (ii) traits that influence local population dynamics contribute to community structure.

The role of the community health nurse in military humanitarian operations: lessons from operation sea signal--Guantanamo Bay, Cuba.

PubMed

Samuels, G L; Sommer, M D

1997-01-01

The military humanitarian mission is an "Operation-Other-Than-War" with a goal of restoring or promoting the ability of a population to care for themselves (U.S. Army, 1990b). One of the primary foci of these operations is the medical care of the target populace. The elements and techniques of primary health care have been used for this purpose, especially as the situation of a population stabilizes and demands a community base for health care programs (Downing, 1989). The knowledge and expertise of a community health nurse is indispensable in both acute and chronic humanitarian situations in performing a comprehensive community needs assessment for the formulation of a community base for health care programs while facilitating a health care system that meets the overall needs of the population. The contributions of community health nurses assigned to Joint Task Force 160, during Operation Sea Signal, bear testimony as to the efficacy of such a "specialized" role in the care of displaced populations.

Self-organization in irregular landscapes: Detecting autogenic interactions from field data using descriptive statistics and dynamical systems theory

NASA Astrophysics Data System (ADS)

Larsen, L.; Watts, D.; Khurana, A.; Anderson, J. L.; Xu, C.; Merritts, D. J.

2015-12-01

The classic signal of self-organization in nature is pattern formation. However, the interactions and feedbacks that organize depositional landscapes do not always result in regular or fractal patterns. How might we detect their existence and effects in these "irregular" landscapes? Emergent landscapes such as newly forming deltaic marshes or some restoration sites provide opportunities to study the autogenic processes that organize landscapes and their physical signatures. Here we describe a quest to understand autogenic vs. allogenic controls on landscape evolution in Big Spring Run, PA, a landscape undergoing restoration from bare-soil conditions to a target wet meadow landscape. The contemporary motivation for asking questions about autogenic vs. allogenic controls is to evaluate how important initial conditions or environmental controls may be for the attainment of management objectives. However, these questions can also inform interpretation of the sedimentary record by enabling researchers to separate signals that may have arisen through self-organization processes from those resulting from environmental perturbations. Over three years at Big Spring Run, we mapped the dynamic evolution of floodplain vegetation communities and distributions of abiotic variables and topography. We used principal component analysis and transition probability analysis to detect associative interactions between vegetation and geomorphic variables and convergent cross-mapping on lidar data to detect causal interactions between biomass and topography. Exploratory statistics revealed that plant communities with distinct morphologies exerted control on landscape evolution through stress divergence (i.e., channel initiation) and promoting the accumulation of fine sediment in channels. Together, these communities participated in a negative feedback that maintains low energy and multiple channels. Because of the spatially explicit nature of this feedback, causal interactions could not be uncovered from convergent cross-mapping with this limited dataset, serving as a reminder that spatially explicit approaches for revealing causality are needed to reconstruct self-organizing mechanisms from data.

Bioavailability of pollutants in bacterial communities of Rodrigo de Freitas Lagoon, Rio de Janeiro, Brazil

PubMed Central

da Fonseca, E.M.; Neto, J.A. Baptista; McAlister, J.J.; Smith, B.J.; Crapez, M.A.C.

2014-01-01

Processes involving heavy metals and other contaminants continue to present unsolved environmental questions. To advance the understanding of geochemical processes that involve the bioavailability of contaminants, cores where collected in the Rodrigo de Freitas lagoon, and analyzed for bacterial activity and metal concentrations. Results would suggest an extremely reducing environment where organic substances seem to be the predominant agents responsible for this geochemical process. Analytical data showed sulphate reduction to be the main agent driving this process, since this kind of bacteria was found to be active in all of the samples analyzed. Esterase enzyme production did not signal the influence of heavy metals and hydrocarbon concentrations and heavy metals were found to be unavailable for biota. However, correlation between results for bacterial biomass and the potentially mobile percentage of the total Ni concentrations would suggest a negative impact. PMID:25477931

SEMICONDUCTOR TECHNOLOGY A signal processing method for the friction-based endpoint detection system of a CMP process

NASA Astrophysics Data System (ADS)

Chi, Xu; Dongming, Guo; Zhuji, Jin; Renke, Kang

2010-12-01

A signal processing method for the friction-based endpoint detection system of a chemical mechanical polishing (CMP) process is presented. The signal process method uses the wavelet threshold denoising method to reduce the noise contained in the measured original signal, extracts the Kalman filter innovation from the denoised signal as the feature signal, and judges the CMP endpoint based on the feature of the Kalman filter innovation sequence during the CMP process. Applying the signal processing method, the endpoint detection experiments of the Cu CMP process were carried out. The results show that the signal processing method can judge the endpoint of the Cu CMP process.

Cicadas impact bird communication in a noisy tropical rainforest

PubMed Central

Hall, Robert; Ray, William; Beck, Angela; Zook, James

2015-01-01

Many animals communicate through acoustic signaling, and “acoustic space” may be viewed as a limited resource that organisms compete for. If acoustic signals overlap, the information in them is masked, so there should be selection toward strategies that reduce signal overlap. The extent to which animals are able to partition acoustic space in acoustically diverse habitats such as tropical forests is poorly known. Here, we demonstrate that a single cicada species plays a major role in the frequency and timing of acoustic communication in a neotropical wet forest bird community. Using an automated acoustic monitor, we found that cicadas vary the timing of their signals throughout the day and that the frequency range and timing of bird vocalizations closely track these signals. Birds significantly avoid temporal overlap with cicadas by reducing and often shutting down vocalizations at the onset of cicada signals that utilize the same frequency range. When birds do vocalize at the same time as cicadas, the vocalizations primarily occur at nonoverlapping frequencies with cicada signals. Our results greatly improve our understanding of the community dynamics of acoustic signaling and reveal how patterns in biotic noise shape the frequency and timing of bird vocalizations in tropical forests. PMID:26023277

Research Resource: A Reference Transcriptome for Constitutive Androstane Receptor and Pregnane X Receptor Xenobiotic Signaling

PubMed Central

Ochsner, Scott A.; Tsimelzon, Anna; Dong, Jianrong; Coarfa, Cristian

2016-01-01

The pregnane X receptor (PXR) (PXR/NR1I3) and constitutive androstane receptor (CAR) (CAR/NR1I2) members of the nuclear receptor (NR) superfamily of ligand-regulated transcription factors are well-characterized mediators of xenobiotic and endocrine-disrupting chemical signaling. The Nuclear Receptor Signaling Atlas maintains a growing library of transcriptomic datasets involving perturbations of NR signaling pathways, many of which involve perturbations relevant to PXR and CAR xenobiotic signaling. Here, we generated a reference transcriptome based on the frequency of differential expression of genes across 159 experiments compiled from 22 datasets involving perturbations of CAR and PXR signaling pathways. In addition to the anticipated overrepresentation in the reference transcriptome of genes encoding components of the xenobiotic stress response, the ranking of genes involved in carbohydrate metabolism and gonadotropin action sheds mechanistic light on the suspected role of xenobiotics in metabolic syndrome and reproductive disorders. Gene Set Enrichment Analysis showed that although acetaminophen, chlorpromazine, and phenobarbital impacted many similar gene sets, differences in direction of regulation were evident in a variety of processes. Strikingly, gene sets representing genes linked to Parkinson's, Huntington's, and Alzheimer's diseases were enriched in all 3 transcriptomes. The reference xenobiotic transcriptome will be supplemented with additional future datasets to provide the community with a continually updated reference transcriptomic dataset for CAR- and PXR-mediated xenobiotic signaling. Our study demonstrates how aggregating and annotating transcriptomic datasets, and making them available for routine data mining, facilitates research into the mechanisms by which xenobiotics and endocrine-disrupting chemicals subvert conventional NR signaling modalities. PMID:27409825

Research Resource: A Reference Transcriptome for Constitutive Androstane Receptor and Pregnane X Receptor Xenobiotic Signaling.

PubMed

Ochsner, Scott A; Tsimelzon, Anna; Dong, Jianrong; Coarfa, Cristian; McKenna, Neil J

2016-08-01

The pregnane X receptor (PXR) (PXR/NR1I3) and constitutive androstane receptor (CAR) (CAR/NR1I2) members of the nuclear receptor (NR) superfamily of ligand-regulated transcription factors are well-characterized mediators of xenobiotic and endocrine-disrupting chemical signaling. The Nuclear Receptor Signaling Atlas maintains a growing library of transcriptomic datasets involving perturbations of NR signaling pathways, many of which involve perturbations relevant to PXR and CAR xenobiotic signaling. Here, we generated a reference transcriptome based on the frequency of differential expression of genes across 159 experiments compiled from 22 datasets involving perturbations of CAR and PXR signaling pathways. In addition to the anticipated overrepresentation in the reference transcriptome of genes encoding components of the xenobiotic stress response, the ranking of genes involved in carbohydrate metabolism and gonadotropin action sheds mechanistic light on the suspected role of xenobiotics in metabolic syndrome and reproductive disorders. Gene Set Enrichment Analysis showed that although acetaminophen, chlorpromazine, and phenobarbital impacted many similar gene sets, differences in direction of regulation were evident in a variety of processes. Strikingly, gene sets representing genes linked to Parkinson's, Huntington's, and Alzheimer's diseases were enriched in all 3 transcriptomes. The reference xenobiotic transcriptome will be supplemented with additional future datasets to provide the community with a continually updated reference transcriptomic dataset for CAR- and PXR-mediated xenobiotic signaling. Our study demonstrates how aggregating and annotating transcriptomic datasets, and making them available for routine data mining, facilitates research into the mechanisms by which xenobiotics and endocrine-disrupting chemicals subvert conventional NR signaling modalities.

A Survey of Memristive Threshold Logic Circuits.

PubMed

Maan, Akshay Kumar; Jayadevi, Deepthi Anirudhan; James, Alex Pappachen

2017-08-01

In this paper, we review different memristive threshold logic (MTL) circuits that are inspired from the synaptic action of the flow of neurotransmitters in the biological brain. The brainlike generalization ability and the area minimization of these threshold logic circuits aim toward crossing Moore's law boundaries at device, circuits, and systems levels. Fast switching memory, signal processing, control systems, programmable logic, image processing, reconfigurable computing, and pattern recognition are identified as some of the potential applications of MTL systems. The physical realization of nanoscale devices with memristive behavior from materials, such as TiO 2 , ferroelectrics, silicon, and polymers, has accelerated research effort in these application areas, inspiring the scientific community to pursue the design of high-speed, low-cost, low-power, and high-density neuromorphic architectures.

Morphogen and community effects determine cell fates in response to BMP4 signaling in human embryonic stem cells.

PubMed

Nemashkalo, Anastasiia; Ruzo, Albert; Heemskerk, Idse; Warmflash, Aryeh

2017-09-01

Paracrine signals maintain developmental states and create cell fate patterns in vivo and influence differentiation outcomes in human embryonic stem cells (hESCs) in vitro Systematic investigation of morphogen signaling is hampered by the difficulty of disentangling endogenous signaling from experimentally applied ligands. Here, we grow hESCs in micropatterned colonies of 1-8 cells ('µColonies') to quantitatively investigate paracrine signaling and the response to external stimuli. We examine BMP4-mediated differentiation in µColonies and standard culture conditions and find that in µColonies, above a threshold concentration, BMP4 gives rise to only a single cell fate, contrary to its role as a morphogen in other developmental systems. Under standard culture conditions BMP4 acts as a morphogen but this requires secondary signals and particular cell densities. We find that a 'community effect' enforces a common fate within µColonies, both in the state of pluripotency and when cells are differentiated, and that this effect allows a more precise response to external signals. Using live cell imaging to correlate signaling histories with cell fates, we demonstrate that interactions between neighbors result in sustained, homogenous signaling necessary for differentiation. © 2017. Published by The Company of Biologists Ltd.

Carbonate system parameters of an algal-dominated reef along West Maui

NASA Astrophysics Data System (ADS)

Prouty, Nancy G.; Yates, Kimberly K.; Smiley, Nathan; Gallagher, Chris; Cheriton, Olivia; Storlazzi, Curt D.

2018-04-01

Constraining coral reef metabolism and carbon chemistry dynamics are fundamental for understanding and predicting reef vulnerability to rising coastal CO2 concentrations and decreasing seawater pH. However, few studies exist along reefs occupying densely inhabited shorelines with known input from land-based sources of pollution. The shallow coral reefs off Kahekili, West Maui, are exposed to nutrient-enriched, low-pH submarine groundwater discharge (SGD) and are particularly vulnerable to the compounding stressors from land-based sources of pollution and lower seawater pH. To constrain the carbonate chemistry system, nutrients and carbonate chemistry were measured along the Kahekili reef flat every 4 h over a 6-day sampling period in March 2016. Abiotic process - primarily SGD fluxes - controlled the carbonate chemistry adjacent to the primary SGD vent site, with nutrient-laden freshwater decreasing pH levels and favoring undersaturated aragonite saturation (Ωarag) conditions. In contrast, diurnal variability in the carbonate chemistry at other sites along the reef flat was driven by reef community metabolism. Superimposed on the diurnal signal was a transition during the second sampling period to a surplus of total alkalinity (TA) and dissolved inorganic carbon (DIC) compared to ocean endmember TA and DIC measurements. A shift from positive net community production and positive net community calcification to negative net community production and negative net community calcification was identified. This transition occurred during a period of increased SGD-driven nutrient loading, lower wave height, and reduced current speeds. This detailed study of carbon chemistry dynamics highlights the need to incorporate local effects of nearshore oceanographic processes into predictions of coral reef vulnerability and resilience.

Using self-organizing maps to classify humpback whale song units and quantify their similarity.

PubMed

Allen, Jenny A; Murray, Anita; Noad, Michael J; Dunlop, Rebecca A; Garland, Ellen C

2017-10-01

Classification of vocal signals can be undertaken using a wide variety of qualitative and quantitative techniques. Using east Australian humpback whale song from 2002 to 2014, a subset of vocal signals was acoustically measured and then classified using a Self-Organizing Map (SOM). The SOM created (1) an acoustic dictionary of units representing the song's repertoire, and (2) Cartesian distance measurements among all unit types (SOM nodes). Utilizing the SOM dictionary as a guide, additional song recordings from east Australia were rapidly (manually) transcribed. To assess the similarity in song sequences, the Cartesian distance output from the SOM was applied in Levenshtein distance similarity analyses as a weighting factor to better incorporate unit similarity in the calculation (previously a qualitative process). SOMs provide a more robust and repeatable means of categorizing acoustic signals along with a clear quantitative measurement of sound type similarity based on acoustic features. This method can be utilized for a wide variety of acoustic databases especially those containing very large datasets and can be applied across the vocalization research community to help address concerns surrounding inconsistency in manual classification.

Array processing for RFID tag localization exploiting multi-frequency signals

NASA Astrophysics Data System (ADS)

Zhang, Yimin; Li, Xin; Amin, Moeness G.

2009-05-01

RFID is an increasingly valuable business and technology tool for electronically identifying, locating, and tracking products, assets, and personnel. As a result, precise positioning and tracking of RFID tags and readers have received considerable attention from both academic and industrial communities. Finding the position of RFID tags is considered an important task in various real-time locating systems (RTLS). As such, numerous RFID localization products have been developed for various applications. The majority of RFID positioning systems is based on the fusion of pieces of relevant information, such as the range and the direction-of-arrival (DOA). For example, trilateration can determine the tag position by using the range information of the tag estimated from three or more spatially separated reader antennas. Triangulation is another method to locate RFID tags that use the direction-of-arrival (DOA) information estimated at multiple spatially separated locations. The RFID tag positions can also be determined through hybrid techniques that combine the range and DOA information. The focus of this paper to study the design and performance of the localization of passive RFID tags using array processing techniques in a multipath environment, and exploiting multi-frequency CW signals. The latter are used to decorrelate the coherent multipath signals for effective DOA estimation and for the purpose of accurate range estimation. Accordingly, the spatial and frequency dimensionalities are fully utilized for robust and accurate positioning of RFID tags.

Quorum Sensing in Marine Microbial Environments.

PubMed

Hmelo, Laura R

2017-01-03

Quorum sensing (QS) is a form of chemical communication used by certain bacteria that regulates a wide range of biogeochemically important bacterial behaviors. Although QS was first observed in a marine bacterium nearly four decades ago, only in the past decade has there been a rise in interest in the role that QS plays in the ocean. It has become clear that QS, regulated by signals such as acylated homoserine lactones (AHLs) or furanosyl-borate diesters [autoinducer-2 (AI-2) molecules], is involved in important processes within the marine carbon cycle, in the health of coral reef ecosystems, and in trophic interactions between a range of eukaryotes and their bacterial associates. The most well-studied QS systems in the ocean occur in surface-attached (biofilm) communities and rely on AHL signaling. AHL-QS is highly sensitive to the chemical and biological makeup of the environment and may respond to anthropogenic change, including ocean acidification and rising sea surface temperatures.

Investigations of Relatively Easy To Construct Antennas With Efficiency in Receiving Schumann Resonances: Preparations for a Miniaturized Reconfigurable ELF Receiver

NASA Technical Reports Server (NTRS)

Farmer, Brian W.; Hannan, Robert C.

2003-01-01

Relatively little is known about the cavity between the Earth and the ionosphere, which opens opportunities for technological advances and unique ideas. One effective means to study this cavity is with extremely low frequency (ELF) antennas. Possible applications of these antennas are global weather prediction, earthquake prediction, planetary exploration, communication, wireless transmission of power, or even a free energy source. The superconducting quantum interference device SQUID) and the coil antenna are the two most acceptable receivers discovered for picking up ELF magnetic fields. Both antennas have the potential for size reduction, allowing them to be portable enough for access to space and even for personal ware. With improvements of these antennas and signal processing, insightful analysis of Schumann resonance (SR) can give the science community a band of radio frequency (RF) signals for improving life here on Earth and exploring beyond.

Quorum Sensing in Marine Microbial Environments

NASA Astrophysics Data System (ADS)

Hmelo, Laura R.

2017-01-01

Quorum sensing (QS) is a form of chemical communication used by certain bacteria that regulates a wide range of biogeochemically important bacterial behaviors. Although QS was first observed in a marine bacterium nearly four decades ago, only in the past decade has there been a rise in interest in the role that QS plays in the ocean. It has become clear that QS, regulated by signals such as acylated homoserine lactones (AHLs) or furanosyl-borate diesters [autoinducer-2 (AI-2) molecules], is involved in important processes within the marine carbon cycle, in the health of coral reef ecosystems, and in trophic interactions between a range of eukaryotes and their bacterial associates. The most well-studied QS systems in the ocean occur in surface-attached (biofilm) communities and rely on AHL signaling. AHL-QS is highly sensitive to the chemical and biological makeup of the environment and may respond to anthropogenic change, including ocean acidification and rising sea surface temperatures.

Listening to the Deep: live monitoring of ocean noise and cetacean acoustic signals.

PubMed

André, M; van der Schaar, M; Zaugg, S; Houégnigan, L; Sánchez, A M; Castell, J V

2011-01-01

The development and broad use of passive acoustic monitoring techniques have the potential to help assessing the large-scale influence of artificial noise on marine organisms and ecosystems. Deep-sea observatories have the potential to play a key role in understanding these recent acoustic changes. LIDO (Listening to the Deep Ocean Environment) is an international project that is allowing the real-time long-term monitoring of marine ambient noise as well as marine mammal sounds at cabled and standalone observatories. Here, we present the overall development of the project and the use of passive acoustic monitoring (PAM) techniques to provide the scientific community with real-time data at large spatial and temporal scales. Special attention is given to the extraction and identification of high frequency cetacean echolocation signals given the relevance of detecting target species, e.g. beaked whales, in mitigation processes, e.g. during military exercises. Copyright © 2011. Published by Elsevier Ltd.

A robust approach to measuring the detective quantum efficiency of radiographic detectors in a clinical setting

NASA Astrophysics Data System (ADS)

McDonald, Michael C.; Kim, H. K.; Henry, J. R.; Cunningham, I. A.

2012-03-01

The detective quantum efficiency (DQE) is widely accepted as a primary measure of x-ray detector performance in the scientific community. A standard method for measuring the DQE, based on IEC 62220-1, requires the system to have a linear response meaning that the detector output signals are proportional to the incident x-ray exposure. However, many systems have a non-linear response due to characteristics of the detector, or post processing of the detector signals, that cannot be disabled and may involve unknown algorithms considered proprietary by the manufacturer. For these reasons, the DQE has not been considered as a practical candidate for routine quality assurance testing in a clinical setting. In this article we described a method that can be used to measure the DQE of both linear and non-linear systems that employ only linear image processing algorithms. The method was validated on a Cesium Iodide based flat panel system that simultaneously stores a raw (linear) and processed (non-linear) image for each exposure. It was found that the resulting DQE was equivalent to a conventional standards-compliant DQE with measurement precision, and the gray-scale inversion and linear edge enhancement did not affect the DQE result. While not IEC 62220-1 compliant, it may be adequate for QA programs.

Changes in predator community structure shifts the efficacy of two warning signals in Arctiid moths.

PubMed

Nokelainen, Ossi; Valkonen, Janne; Lindstedt, Carita; Mappes, Johanna

2014-05-01

Polymorphism in warning coloration is puzzling because positive frequency-dependent selection by predators is expected to promote monomorphic warning signals in defended prey. We studied predation on the warning-coloured wood tiger moth (Parasemia plantaginis) by using artificial prey resembling white and yellow male colour morphs in five separate populations with different naturally occurring morph frequencies. We tested whether predation favours one of the colour morphs over the other and whether that is influenced either by local, natural colour morph frequencies or predator community composition. We found that yellow specimens were attacked less than white ones regardless of the local frequency of the morphs indicating frequency-independent selection, but predation did depend on predator community composition: yellows suffered less attacks when Paridae were abundant, whereas whites suffered less attacks when Prunellidae were abundant. Our results suggest that spatial heterogeneity in predator community composition can generate a geographical mosaic of selection facilitating the evolution of polymorphic warning signals. This is the first time this mechanism gains experimental support. Altogether, this study sheds light on the evolution of adaptive coloration in heterogeneous environments. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

Electromagnetic spectrum management system

DOEpatents

Seastrand, Douglas R.

2017-01-31

A system for transmitting a wireless countermeasure signal to disrupt third party communications is disclosed that include an antenna configured to receive wireless signals and transmit wireless counter measure signals such that the wireless countermeasure signals are responsive to the received wireless signals. A receiver processes the received wireless signals to create processed received signal data while a spectrum control module subtracts known source signal data from the processed received signal data to generate unknown source signal data. The unknown source signal data is based on unknown wireless signals, such as enemy signals. A transmitter is configured to process the unknown source signal data to create countermeasure signals and transmit a wireless countermeasure signal over the first antenna or a second antenna to thereby interfere with the unknown wireless signals.

Monitoring obesity prevalence in the United States through bookmarking activities in online food portals

PubMed Central

Trattner, Christoph; Parra, Denis; Elsweiler, David

2017-01-01

Studying the impact of food consumption on people’s health is a serious matter for its implications on public policy, but it has traditionally been a slow process since it requires information gathered through expensive collection processes such as surveys, census and systematic reviews of research articles. We argue that this process could be supported and hastened using data collected via online social networks. In this work we investigate the relationships between the online traces left behind by users of a large US online food community and the prevalence of obesity in 47 states and 311 counties in the US. Using data associated with the recipes bookmarked over an 9-year period by 144,839 users of the Allrecipes.com food website residing throughout the US, several hierarchical regression models are created to (i) shed light on these relations and (ii) establish their magnitude. The results of our analysis provide strong evidence that bookmarking activities on recipes in online food communities can provide a signal allowing food and health related issues, such as obesity to be better understood and monitored. We discover that higher fat and sugar content in bookmarked recipes is associated with higher rates of obesity. The dataset is complicated, but strong temporal and geographical trends are identifiable. We show the importance of accounting for these trends in the modeling process. PMID:28636665

Exploiting Satellite Archives to Estimate Global Glacier Volume Changes

NASA Astrophysics Data System (ADS)

McNabb, R. W.; Nuth, C.; Kääb, A.; Girod, L.

2017-12-01

In the past decade, the availability of, and ability to process, remote sensing data over glaciers has expanded tremendously. Newly opened satellite image archives, combined with new processing techniques as well as increased computing power and storage capacity, have given the glaciological community the ability to observe and investigate glaciological processes and changes on a truly global scale. In particular, the opening of the ASTER archives provides further opportunities to both estimate and monitor glacier elevation and volume changes globally, including potentially on sub-annual timescales. With this explosion of data availability, however, comes the challenge of seeing the forest instead of the trees. The high volume of data available means that automated detection and proper handling of errors and biases in the data becomes critical, in order to properly study the processes that we wish to see. This includes holes and blunders in digital elevation models (DEMs) derived from optical data or penetration of radar signals leading to biases in DEMs derived from radar data, among other sources. Here, we highlight new advances in the ability to sift through high-volume datasets, and apply these techniques to estimate recent glacier volume changes in the Caucasus Mountains, Scandinavia, Africa, and South America. By properly estimating and correcting for these biases, we additionally provide a detailed accounting of the uncertainties in these estimates of volume changes, leading to more reliable results that have applicability beyond the glaciological community.

Workshop targets development of geodetic transient detection methods: 2009 SCEC Annual Meeting: Workshop on transient anomalous strain detection; Palm Springs, California, 12-13 September 2009

USGS Publications Warehouse

Murray-Moraleda, Jessica R.; Lohman, Rowena

2010-01-01

The Southern California Earthquake Center (SCEC) is a community of researchers at institutions worldwide working to improve understanding of earthquakes and mitigate earthquake risk. One of SCEC's priority objectives is to “develop a geodetic network processing system that will detect anomalous strain transients.” Given the growing number of continuously recording geodetic networks consisting of hundreds of stations, an automated means for systematically searching data for transient signals, especially in near real time, is critical for network operations, hazard monitoring, and event response. The SCEC Transient Detection Test Exercise began in 2008 to foster an active community of researchers working on this problem, explore promising methods, and combine effective approaches in novel ways. A workshop was held in California to assess what has been learned thus far and discuss areas of focus as the project moves forward.

Signal Processing for Metagenomics: Extracting Information from the Soup

PubMed Central

Rosen, Gail L.; Sokhansanj, Bahrad A.; Polikar, Robi; Bruns, Mary Ann; Russell, Jacob; Garbarine, Elaine; Essinger, Steve; Yok, Non

2009-01-01

Traditionally, studies in microbial genomics have focused on single-genomes from cultured species, thereby limiting their focus to the small percentage of species that can be cultured outside their natural environment. Fortunately, recent advances in high-throughput sequencing and computational analyses have ushered in the new field of metagenomics, which aims to decode the genomes of microbes from natural communities without the need for cultivation. Although metagenomic studies have shed a great deal of insight into bacterial diversity and coding capacity, several computational challenges remain due to the massive size and complexity of metagenomic sequence data. Current tools and techniques are reviewed in this paper which address challenges in 1) genomic fragment annotation, 2) phylogenetic reconstruction, 3) functional classification of samples, and 4) interpreting complementary metaproteomics and metametabolomics data. Also surveyed are important applications of metagenomic studies, including microbial forensics and the roles of microbial communities in shaping human health and soil ecology. PMID:20436876

Classification of functional interactions from multi-electrodes data using conditional modularity analysis

NASA Astrophysics Data System (ADS)

Makhtar, Siti Noormiza; Senik, Mohd Harizal

2018-02-01

The availability of massive amount of neuronal signals are attracting widespread interest in functional connectivity analysis. Functional interactions estimated by multivariate partial coherence analysis in the frequency domain represent the connectivity strength in this study. Modularity is a network measure for the detection of community structure in network analysis. The discovery of community structure for the functional neuronal network was implemented on multi-electrode array (MEA) signals recorded from hippocampal regions in isoflurane-anaesthetized Lister-hooded rats. The analysis is expected to show modularity changes before and after local unilateral kainic acid (KA)-induced epileptiform activity. The result is presented using color-coded graphic of conditional modularity measure for 19 MEA nodes. This network is separated into four sub-regions to show the community detection within each sub-region. The results show that classification of neuronal signals into the inter- and intra-modular nodes is feasible using conditional modularity analysis. Estimation of segregation properties using conditional modularity analysis may provide further information about functional connectivity from MEA data.

From Ships in the Night to Exchanges in the Piazza: Renegotiating the Researcher-Stakeholder Nexus in Climate Adaptation

NASA Astrophysics Data System (ADS)

Jackson, S. T.

2016-12-01

A substantial divide remains between the communities of research, embedded largely in universities and science agencies, and the communities of practice, comprising the natural-resource managers and other decision-makers in diverse federal, state, local, and tribal agencies and in private-sector enterprises and organizations. In spite of clear needs and best intentions, engagement among the respective communities is imperfect; researchers and stakeholders are often like ships passing in the night, exchanging brief, cryptic signals. A variety of boundary organizations have been developed to facilitate the communications, and a number of successful models for researcher-stakeholder exchange and engagement have been applied. At least two substantial challenges remain. First, how can the successes be scaled up and proliferated to meet the vast demands posed by climate adaptation? Second, how can the various boundary organizations most effectively foster this expansion, individually and collectively? Meeting these challenges will require coordination among the respective organizations, changes in the cultures of research and management, and careful assessment of process and outcomes.

From ships in the night to exchanges in the piazza: Renegotiating the researcher-stakeholder nexus in climate adaptation

NASA Astrophysics Data System (ADS)

Jackson, S. T.

2015-12-01

A substantial divide remains between the communities of research, embedded largely in universities and science agencies, and the communities of practice, comprising the natural-resource managers and other decision-makers in diverse federal, state, local, and tribal agencies and in private-sector enterprises and organizations. In spite of clear needs and best intentions, engagement among the respective communities is imperfect; researchers and stakeholders are often like ships passing in the night, exchanging brief, cryptic signals. A variety of boundary organizations have been developed to facilitate the communications, and a number of successful models for researcher-stakeholder exchange and engagement have been applied. At least two substantial challenges remain. First, how can the successes be scaled up and proliferated to meet the vast demands posed by climate adaptation? Second, how can the various boundary organizations most effectively foster this expansion, individually and collectively? Meeting these challenges will require coordination among the respective organizations, changes in the cultures of research and management, and careful assessment of process and outcomes.

Understanding community-based processes for research ethics review: a national study.

PubMed

Shore, Nancy; Brazauskas, Ruta; Drew, Elaine; Wong, Kristine A; Moy, Lisa; Baden, Andrea Corage; Cyr, Kirsten; Ulevicus, Jocelyn; Seifer, Sarena D

2011-12-01

Institutional review boards (IRBs), designed to protect individual study participants, do not routinely assess community consent, risks, and benefits. Community groups are establishing ethics review processes to determine whether and how research is conducted in their communities. To strengthen the ethics review of community-engaged research, we sought to identify and describe these processes. In 2008 we conducted an online survey of US-based community groups and community-institutional partnerships involved in human-participants research. We identified 109 respondents who met participation criteria and had ethics review processes in place. The respondents' processes mainly functioned through community-institutional partnerships, community-based organizations, community health centers, and tribal organizations. These processes had been created primarily to ensure that the involved communities were engaged in and directly benefited from research and were protected from research harms. The primary process benefits included giving communities a voice in determining which studies were conducted and ensuring that studies were relevant and feasible, and that they built community capacity. The primary process challenges were the time and resources needed to support the process. Community-based processes for ethics review consider community-level ethical issues that institution-based IRBs often do not.

Community-based health care for indigenous women in Mexico: a qualitative evaluation

PubMed Central

2014-01-01

Introduction Indigenous women in Mexico represent a vulnerable population in which three kinds of discrimination converge (ethnicity, gender and class), having direct repercussions on health status. The discrimination and inequity in health care settings brought this population to the fore as a priority group for institutional action. The objective of this study was to evaluate the processes and performance of the “Casa de la Mujer Indígena”, a community based project for culturally and linguistically appropriate service delivery for indigenous women. The evaluation summarizes perspectives from diverse stakeholders involved in the implementation of the model, including users, local authorities, and institutional representatives. Methods The study covered five Casas implementation sites located in four Mexican states. A qualitative process evaluation focused on systematically analyzing the Casas project processes and performance was conducted using archival information and semi-structured interviews. Sixty-two interviews were conducted, and grounded theory approach was applied for data analysis. Results Few similarities were observed between the proposed model of service delivery and its implementation in diverse locations, signaling discordant operating processes. Evidence gathered from Casas personnel highlighted their ability to detect obstetric emergencies and domestic violence cases, as well as contribute to the empowerment of women in the indigenous communities served by the project. These themes directly translated to increases in the reporting of abuse and referrals for obstetric emergencies. Conclusions The model’s cultural and linguistic competency, and contributions to increased referrals for obstetric emergencies and abuse are notable successes. The flexibility and community-based nature of the model has allowed it to be adapted to the particularities of diverse indigenous contexts. Local, culturally appropriate implementation has been facilitated by the fact that the Casas have been implemented with local leadership and local women have taken ownership. Users express overall satisfaction with service delivery, while providing constructive feedback for the improvement of existing Casas, as well as more cost-effective implementation of the model in new sites. Integration of user’s input obtained from this process evaluation into future planning will undoubtedly increase buy-in. The Casas model is pertinent and viable to other contexts where indigenous women experience disparities in care. PMID:24393517

Community-based health care for indigenous women in Mexico: a qualitative evaluation.

PubMed

Pelcastre-Villafuerte, Blanca; Ruiz, Myriam; Meneses, Sergio; Amaya, Claudia; Márquez, Margarita; Taboada, Arianna; Careaga, Katherine

2014-01-06

Indigenous women in Mexico represent a vulnerable population in which three kinds of discrimination converge (ethnicity, gender and class), having direct repercussions on health status. The discrimination and inequity in health care settings brought this population to the fore as a priority group for institutional action. The objective of this study was to evaluate the processes and performance of the "Casa de la Mujer Indígena", a community based project for culturally and linguistically appropriate service delivery for indigenous women. The evaluation summarizes perspectives from diverse stakeholders involved in the implementation of the model, including users, local authorities, and institutional representatives. The study covered five Casas implementation sites located in four Mexican states. A qualitative process evaluation focused on systematically analyzing the Casas project processes and performance was conducted using archival information and semi-structured interviews. Sixty-two interviews were conducted, and grounded theory approach was applied for data analysis. Few similarities were observed between the proposed model of service delivery and its implementation in diverse locations, signaling discordant operating processes. Evidence gathered from Casas personnel highlighted their ability to detect obstetric emergencies and domestic violence cases, as well as contribute to the empowerment of women in the indigenous communities served by the project. These themes directly translated to increases in the reporting of abuse and referrals for obstetric emergencies. The model's cultural and linguistic competency, and contributions to increased referrals for obstetric emergencies and abuse are notable successes. The flexibility and community-based nature of the model has allowed it to be adapted to the particularities of diverse indigenous contexts. Local, culturally appropriate implementation has been facilitated by the fact that the Casas have been implemented with local leadership and local women have taken ownership. Users express overall satisfaction with service delivery, while providing constructive feedback for the improvement of existing Casas, as well as more cost-effective implementation of the model in new sites. Integration of user's input obtained from this process evaluation into future planning will undoubtedly increase buy-in. The Casas model is pertinent and viable to other contexts where indigenous women experience disparities in care.

Sensory-based niche partitioning in a multiple predator - multiple prey community.

PubMed

Falk, Jay J; ter Hofstede, Hannah M; Jones, Patricia L; Dixon, Marjorie M; Faure, Paul A; Kalko, Elisabeth K V; Page, Rachel A

2015-06-07

Many predators and parasites eavesdrop on the communication signals of their prey. Eavesdropping is typically studied as dyadic predator-prey species interactions; yet in nature, most predators target multiple prey species and most prey must evade multiple predator species. The impact of predator communities on prey signal evolution is not well understood. Predators could converge in their preferences for conspicuous signal properties, generating competition among predators and natural selection on particular prey signal features. Alternatively, predator species could vary in their preferences for prey signal properties, resulting in sensory-based niche partitioning of prey resources. In the Neotropics, many substrate-gleaning bats use the mate-attraction songs of male katydids to locate them as prey. We studied mechanisms of niche partitioning in four substrate-gleaning bat species and found they are similar in morphology, echolocation signal design and prey-handling ability, but each species preferred different acoustic features of male song in 12 sympatric katydid species. This divergence in predator preference probably contributes to the coexistence of many substrate-gleaning bat species in the Neotropics, and the substantial diversity in the mate-attraction signals of katydids. Our results provide insight into how multiple eavesdropping predator species might influence prey signal evolution through sensory-based niche partitioning. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Community phylogenetics at the biogeographical scale: cold tolerance, niche conservatism and the structure of North American forests.

PubMed

Hawkins, Bradford A; Rueda, Marta; Rangel, Thiago F; Field, Richard; Diniz-Filho, José Alexandre F; Linder, Peter

2014-01-01

Aim The fossil record has led to a historical explanation for forest diversity gradients within the cool parts of the Northern Hemisphere, founded on a limited ability of woody angiosperm clades to adapt to mid-Tertiary cooling. We tested four predictions of how this should be manifested in the phylogenetic structure of 91,340 communities: (1) forests to the north should comprise species from younger clades (families) than forests to the south; (2) average cold tolerance at a local site should be associated with the mean family age (MFA) of species; (3) minimum temperature should account for MFA better than alternative environmental variables; and (4) traits associated with survival in cold climates should evolve under a niche conservatism constraint. Location The contiguous United States. Methods We extracted angiosperms from the US Forest Service's Forest Inventory and Analysis database. MFA was calculated by assigning age of the family to which each species belongs and averaging across the species in each community. We developed a phylogeny to identify phylogenetic signal in five traits: realized cold tolerance, seed size, seed dispersal mode, leaf phenology and height. Phylogenetic signal representation curves and phylogenetic generalized least squares were used to compare patterns of trait evolution against Brownian motion. Eleven predictors structured at broad or local scales were generated to explore relationships between environment and MFA using random forest and general linear models. Results Consistent with predictions, (1) southern communities comprise angiosperm species from older families than northern communities, (2) cold tolerance is the trait most strongly associated with local MFA, (3) minimum temperature in the coldest month is the environmental variable that best describes MFA, broad-scale variables being much stronger correlates than local-scale variables, and (4) the phylogenetic structures of cold tolerance and at least one other trait associated with survivorship in cold climates indicate niche conservatism. Main conclusions Tropical niche conservatism in the face of long-term climate change, probably initiated in the Late Cretaceous associated with the rise of the Rocky Mountains, is a strong driver of the phylogenetic structure of the angiosperm component of forest communities across the USA. However, local deterministic and/or stochastic processes account for perhaps a quarter of the variation in the MFA of local communities.

Electromagnetic spectrum management system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seastrand, Douglas R.

A system for transmitting a wireless countermeasure signal to disrupt third party communications is disclosed that include an antenna configured to receive wireless signals and transmit wireless counter measure signals such that the wireless countermeasure signals are responsive to the received wireless signals. A receiver processes the received wireless signals to create processed received signal data while a spectrum control module subtracts known source signal data from the processed received signal data to generate unknown source signal data. The unknown source signal data is based on unknown wireless signals, such as enemy signals. A transmitter is configured to process themore » unknown source signal data to create countermeasure signals and transmit a wireless countermeasure signal over the first antenna or a second antenna to thereby interfere with the unknown wireless signals.« less

47 CFR 76.54 - Significantly viewed signals; method to be followed for special showings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... located, in whole or in part, and on all other system community units, franchisees, and franchise.... 339(d). (j) Notwithstanding the requirements of this section, the signal of a television broadcast...

Plant signalling: the opportunities and dangers of chemical communication.

PubMed

Adler, Frederick R

2011-04-23

The notion of chemical communication between plants and other organisms has gone from being viewed as a fringe idea to an accepted ecological phenomenon only recently. An Organized Oral Session at the August 2010 Ecological Society of America meeting in Pittsburgh examined the role of plant signalling both within and between plants, with speakers addressing the remarkably wide array of effects that plant signals have on plant physiology, species interactions and entire communities. In addition to the familiar way that plants communicate with mutualists like pollinators and fruit dispersers through both chemical and visual cues, speakers at this session described how plants communicate with themselves, with each other, with herbivores and with predators of those herbivores. These plant signals create a complex odour web superimposed upon the more classical food web itself, with its own dynamics in the face of exotic species and rapid community assembly and disassembly.

Signal existence verification (SEV) for GPS low received power signal detection using the time-frequency approach.

PubMed

Jan, Shau-Shiun; Sun, Chih-Cheng

2010-01-01

The detection of low received power of global positioning system (GPS) signals in the signal acquisition process is an important issue for GPS applications. Improving the miss-detection problem of low received power signal is crucial, especially for urban or indoor environments. This paper proposes a signal existence verification (SEV) process to detect and subsequently verify low received power GPS signals. The SEV process is based on the time-frequency representation of GPS signal, and it can capture the characteristic of GPS signal in the time-frequency plane to enhance the GPS signal acquisition performance. Several simulations and experiments are conducted to show the effectiveness of the proposed method for low received power signal detection. The contribution of this work is that the SEV process is an additional scheme to assist the GPS signal acquisition process in low received power signal detection, without changing the original signal acquisition or tracking algorithms.

Looking inside and out: the impact of employee and community demographic composition on organizational diversity climate.

PubMed

Pugh, S Douglas; Dietz, Joerg; Brief, Arthur P; Wiley, Jack W

2008-11-01

An organization's diversity climate refers to employees' shared perceptions of the policies and practices that communicate the extent to which fostering diversity and eliminating discrimination is a priority in the organization. The authors propose a salient element of the organizational context, the racial composition of the community where the organization is located, serves an important signaling function that shapes the formation of climate perceptions. In a study of 142 retail bank units in the United States, evidence is found for a relationship between the racial composition of an organization's workforce and diversity climate that is moderated by the racial composition of the community where the organization is located. The results suggest that when few racial minorities live in the community in which an organization is embedded, workforce diversity has an impact on employees' diversity climate perceptions. As racial minority popular share increases, workforce diversity tends to lose this signaling value.

System for monitoring an industrial or biological process

DOEpatents

Gross, Kenneth C.; Wegerich, Stephan W.; Vilim, Rick B.; White, Andrew M.

1998-01-01

A method and apparatus for monitoring and responding to conditions of an industrial process. Industrial process signals, such as repetitive manufacturing, testing and operational machine signals, are generated by a system. Sensor signals characteristic of the process are generated over a time length and compared to reference signals over the time length. The industrial signals are adjusted over the time length relative to the reference signals, the phase shift of the industrial signals is optimized to the reference signals and the resulting signals output for analysis by systems such as SPRT.

System for monitoring an industrial or biological process

DOEpatents

Gross, K.C.; Wegerich, S.W.; Vilim, R.B.; White, A.M.

1998-06-30

A method and apparatus are disclosed for monitoring and responding to conditions of an industrial process. Industrial process signals, such as repetitive manufacturing, testing and operational machine signals, are generated by a system. Sensor signals characteristic of the process are generated over a time length and compared to reference signals over the time length. The industrial signals are adjusted over the time length relative to the reference signals, the phase shift of the industrial signals is optimized to the reference signals and the resulting signals output for analysis by systems such as SPRT. 49 figs.

A nonlinear cointegration approach with applications to structural health monitoring

NASA Astrophysics Data System (ADS)

Shi, H.; Worden, K.; Cross, E. J.

2016-09-01

One major obstacle to the implementation of structural health monitoring (SHM) is the effect of operational and environmental variabilities, which may corrupt the signal of structural degradation. Recently, an approach inspired from the community of econometrics, called cointegration, has been employed to eliminate the adverse influence from operational and environmental changes and still maintain sensitivity to structural damage. However, the linear nature of cointegration may limit its application when confronting nonlinear relations between system responses. This paper proposes a nonlinear cointegration method based on Gaussian process regression (GPR); the method is constructed under the Engle-Granger framework, and tests for unit root processes are conducted both before and after the GPR is applied. The proposed approach is examined with real engineering data from the monitoring of the Z24 Bridge.

Effect of Copper Treatment on the Composition and Function of the Bacterial Community in the Sponge Haliclona cymaeformis

PubMed Central

Tian, Ren-Mao; Wang, Yong; Bougouffa, Salim; Gao, Zhao-Ming; Cai, Lin; Zhang, Wei-Peng; Bajic, Vladimir

2014-01-01

ABSTRACT Marine sponges are the most primitive metazoan and host symbiotic microorganisms. They are crucial components of the marine ecological system and play an essential role in pelagic processes. Copper pollution is currently a widespread problem and poses a threat to marine organisms. Here, we examined the effects of copper treatment on the composition of the sponge-associated bacterial community and the genetic features that facilitate the survival of enriched bacteria under copper stress. The 16S rRNA gene sequencing results showed that the sponge Haliclona cymaeformis harbored symbiotic sulfur-oxidizing Ectothiorhodospiraceae and photosynthetic Cyanobacteria as dominant species. However, these autotrophic bacteria decreased substantially after treatment with a high copper concentration, which enriched for a heterotrophic-bacterium-dominated community. Metagenomic comparison revealed a varied profile of functional genes and enriched functions, including bacterial motility and chemotaxis, extracellular polysaccharide and capsule synthesis, virulence-associated genes, and genes involved in cell signaling and regulation, suggesting short-period mechanisms of the enriched bacterial community for surviving copper stress in the microenvironment of the sponge. Microscopic observation and comparison revealed dynamic bacterial aggregation within the matrix and lysis of sponge cells. The bacteriophage community was also enriched, and the complete genome of a dominant phage was determined, implying that a lytic phage cycle was stimulated by the high copper concentration. This study demonstrated a copper-induced shift in the composition of functional genes of the sponge-associated bacterial community, revealing the selective effect of copper treatment on the functions of the bacterial community in the microenvironment of the sponge. PMID:25370493

Optical signal processing

NASA Technical Reports Server (NTRS)

Casasent, D.

1978-01-01

The article discusses several optical configurations used for signal processing. Electronic-to-optical transducers are outlined, noting fixed window transducers and moving window acousto-optic transducers. Folded spectrum techniques are considered, with reference to wideband RF signal analysis, fetal electroencephalogram analysis, engine vibration analysis, signal buried in noise, and spatial filtering. Various methods for radar signal processing are described, such as phased-array antennas, the optical processing of phased-array data, pulsed Doppler and FM radar systems, a multichannel one-dimensional optical correlator, correlations with long coded waveforms, and Doppler signal processing. Means for noncoherent optical signal processing are noted, including an optical correlator for speech recognition and a noncoherent optical correlator.

Precision Measurement of Black Hole Binary Dynamics: Analyzing the LISA Data Stream

NASA Technical Reports Server (NTRS)

McWilliams, Sean T.; Thorpe, James Ira; Baker, John G.; Arnaud, Keith A.; Kelly, Bernard J.

2008-01-01

One of the richest potential sources of insight into fundamental physics that LISA will be capable of observing is the inspiral of supermassive black hole binaries (BHBs). However, the data analysis challenge presented by the LISA data stream is quite unlike the situation for present day gravitational wave detectors. In order to make the precision measurements necessary to achieve LISA's science goals, the BHB signal must be distinguished from a data stream that not only contains instrumental noise, but potentially thousands of other signals as well, so that the "background" we wish to separate out to focus on the BHB signal is likely to be highly nonstationary and nongaussian, as well as being of scientific interest in its own right. In addition, whereas the theoretical templates that we calculate in order to ultimately estimate the parameters can afford to be somewhat inaccurate and still be effective for present day and near future detectors, this is not the case for LISA, and extremely high fidelity of the theoretical templates for high signal-to-noise signals will be required to prevent theoretical errors from dominating the parameter estimates. NVe, will describe efforts in the community of LISA data analysts to address the challenges regarding the specific issue of BHB signals. These efforts include using a Markov Chain Monte Carlo approach with the freedom to model the BHB and the other signals present in the data stream simultaneously, rather than trying to remove other signals and risk biasing the remaining data. The Mock LISA Data Challenge is a community of LISA scientists who generate rounds of simulated LISA noise with increasingly difficult signal content, and invite the LISA data analysis community to exercise their methods, or develop new methods, in an attempt to extract the parameters for the signals embedded in the mock data. In addition to practical approaches such ,is this to assess the level of parameter accuracy, one can apply the Fisher matrix formalism to assess both the statistical errors from noise and the theoretical errors

The Representation of Heart Development in the Gene Ontology

PubMed Central

Khodiyar, Varsha K.; Hill, David P.; Howe, Doug; Berardini, Tanya Z.; Tweedie, Susan; Talmud, Philippa J.; Breckenridge, Ross; Bhattarcharya, Shoumo; Riley, Paul; Scambler, Peter; Lovering, Ruth C.

2012-01-01

An understanding of heart development is critical in any systems biology approach to cardiovascular disease. The interpretation of data generated from high-throughput technologies (such as microarray and proteomics) is also essential to this approach. However, characterizing the role of genes in the processes underlying heart development and cardiovascular disease involves the non-trivial task of data analysis and integration of previous knowledge. The Gene Ontology (GO) Consortium provides structured controlled biological vocabularies that are used to summarize previous functional knowledge for gene products across all species. One aspect of GO describes biological processes, such as development and signaling. In order to support high-throughput cardiovascular research, we have initiated an effort to fully describe heart development in GO; expanding the number of GO terms describing heart development from 12 to over 280. This new ontology describes heart morphogenesis, the differentiation of specific cardiac cell types, and the involvement of signaling pathways in heart development and aligns GO with the current views of the heart development research community and its representation in the literature. This extension of GO allows gene product annotators to comprehensively capture the genetic program leading to the developmental progression of the heart. This will enable users to integrate heart development data across species, resulting in the comprehensive retrieval of information about this subject. The revised GO structure, combined with gene product annotations, should improve the interpretation of data from high-throughput methods in a variety of cardiovascular research areas, including heart development, congenital cardiac disease, and cardiac stem cell research. Additionally, we invite the heart development community to contribute to the expansion of this important dataset for the benefit of future research in this area. PMID:21419760

Applied digital signal processing systems for vortex flowmeter with digital signal processing.

PubMed

Xu, Ke-Jun; Zhu, Zhi-Hai; Zhou, Yang; Wang, Xiao-Fen; Liu, San-Shan; Huang, Yun-Zhi; Chen, Zhi-Yuan

2009-02-01

The spectral analysis is combined with digital filter to process the vortex sensor signal for reducing the effect of disturbance at low frequency from pipe vibrations and increasing the turndown ratio. Using digital signal processing chip, two kinds of digital signal processing systems are developed to implement these algorithms. One is an integrative system, and the other is a separated system. A limiting amplifier is designed in the input analog condition circuit to adapt large amplitude variation of sensor signal. Some technique measures are taken to improve the accuracy of the output pulse, speed up the response time of the meter, and reduce the fluctuation of the output signal. The experimental results demonstrate the validity of the digital signal processing systems.

Aspects of structural health and condition monitoring of offshore wind turbines

PubMed Central

Antoniadou, I.; Dervilis, N.; Papatheou, E.; Maguire, A. E.; Worden, K.

2015-01-01

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector. PMID:25583864

Aspects of structural health and condition monitoring of offshore wind turbines.

PubMed

Antoniadou, I; Dervilis, N; Papatheou, E; Maguire, A E; Worden, K

2015-02-28

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector.

A simple solution for model comparison in bold imaging: the special case of reward prediction error and reward outcomes.

PubMed

Erdeniz, Burak; Rohe, Tim; Done, John; Seidler, Rachael D

2013-01-01

Conventional neuroimaging techniques provide information about condition-related changes of the BOLD (blood-oxygen-level dependent) signal, indicating only where and when the underlying cognitive processes occur. Recently, with the help of a new approach called "model-based" functional neuroimaging (fMRI), researchers are able to visualize changes in the internal variables of a time varying learning process, such as the reward prediction error or the predicted reward value of a conditional stimulus. However, despite being extremely beneficial to the imaging community in understanding the neural correlates of decision variables, a model-based approach to brain imaging data is also methodologically challenging due to the multicollinearity problem in statistical analysis. There are multiple sources of multicollinearity in functional neuroimaging including investigations of closely related variables and/or experimental designs that do not account for this. The source of multicollinearity discussed in this paper occurs due to correlation between different subjective variables that are calculated very close in time. Here, we review methodological approaches to analyzing such data by discussing the special case of separating the reward prediction error signal from reward outcomes.

Contemporary ultrasonic signal processing approaches for nondestructive evaluation of multilayered structures

NASA Astrophysics Data System (ADS)

Zhang, Guang-Ming; Harvey, David M.

2012-03-01

Various signal processing techniques have been used for the enhancement of defect detection and defect characterisation. Cross-correlation, filtering, autoregressive analysis, deconvolution, neural network, wavelet transform and sparse signal representations have all been applied in attempts to analyse ultrasonic signals. In ultrasonic nondestructive evaluation (NDE) applications, a large number of materials have multilayered structures. NDE of multilayered structures leads to some specific problems, such as penetration, echo overlap, high attenuation and low signal-to-noise ratio. The signals recorded from a multilayered structure are a class of very special signals comprised of limited echoes. Such signals can be assumed to have a sparse representation in a proper signal dictionary. Recently, a number of digital signal processing techniques have been developed by exploiting the sparse constraint. This paper presents a review of research to date, showing the up-to-date developments of signal processing techniques made in ultrasonic NDE. A few typical ultrasonic signal processing techniques used for NDE of multilayered structures are elaborated. The practical applications and limitations of different signal processing methods in ultrasonic NDE of multilayered structures are analysed.

The Satellite Technology Demonstration's Experiences with Varied Terrestrial Signal Distribution Methods. Satellite Technology Demonstration, Technical Report No. 0335.

ERIC Educational Resources Information Center

Anderson, Frank; And Others

Though the Satellite Technology Demonstration (STD) system had the capacity to deliver quality broadcast signals to specially designed ground terminals its budget did not provide for more than one receiver in each rural community. In order to translate the satellite signal into a broadcast available to the individual home viewer, several systems…

Behavioral evidence for community-wide species discrimination from echolocation calls in bats.

PubMed

Schuchmann, Maike; Siemers, Björn M

2010-07-01

Recognizing species identity is crucial for many aspects of animal life and is often mediated by acoustic signals. Although most animals are able to distinguish acoustic signals of their own species from other sympatrically occurring species, it is yet unknown whether animals can distinguish among acoustic signals of different closely related sympatric species. In this context, echolocating bats are a particularly interesting model system: their echolocation system evolved primarily for spatial orientation and foraging, but recent studies indicate that echolocation also has an important communicative function. Yet, the role of echolocation calls for species discrimination and thus potentially for interspecific communication has not been investigated. Using a behavioral discrimination assay, we found that two species of wild horseshoe bats could discriminate calls of their own species from those of three sympatric congeneric species. We further show that the bats were able to discriminate between echolocation calls of different congeneric species from the local community. In both cases, discrimination ability was high despite strong overlap of species' call frequency bands. This study provides the first experimental evidence for species discrimination based on echolocation calls. On a more general level, it shows for the first time that animals can distinguish among acoustic signals of different closely related and ecologically similar species from their local community.

AOD furnace splash soft-sensor in the smelting process based on improved BP neural network

NASA Astrophysics Data System (ADS)

Ma, Haitao; Wang, Shanshan; Wu, Libin; Yu, Ying

2017-11-01

In view of argon oxygen refining low carbon ferrochrome production process, in the splash of smelting process as the research object, based on splash mechanism analysis in the smelting process , using multi-sensor information fusion and BP neural network modeling techniques is proposed in this paper, using the vibration signal, the audio signal and the flame image signal in the furnace as the characteristic signal of splash, the vibration signal, the audio signal and the flame image signal in the furnace integration and modeling, and reconstruct splash signal, realize the splash soft measurement in the smelting process, the simulation results show that the method can accurately forecast splash type in the smelting process, provide a new method of measurement for forecast splash in the smelting process, provide more accurate information to control splash.

Significant Phylogenetic Signal and Climate-Related Trends in Leaf Caloric Value from Tropical to Cold-Temperate Forests.

PubMed

Song, Guangyan; Li, Ying; Zhang, Jiahui; Li, Meiling; Hou, Jihua; He, Nianpeng

2016-11-18

Leaf caloric value (LCV) is a useful index to represent the conversion efficiency of leaves for solar energy. We investigated the spatial pattern of LCV and explored the factors (phylogeny, climate, and soil) that influence them at a large scale by determining LCV standardized by leaf area in 920 plant species from nine forest communities along the 3700 km North-South Transect of Eastern China. LCV ranged from 0.024 to 1.056 kJ cm -2 with an average of 0.151 kJ cm -2 . LCV declined linearly with increasing latitude along the transect. Altogether, 57.29% of the total variation in LCV was explained by phylogenetic group (44.03% of variation), climate (1.27%), soil (0.02%) and their interacting effects. Significant phylogenetic signals in LCV were observed not only within forest communities but also across the whole transect. This phylogenetic signal was higher at higher latitudes, reflecting latitudinal change in the species composition of forest communities from complex to simple. We inferred that climate influences the spatial pattern of LCV through directly regulating the species composition of plant communities, since most plant species might tolerate only a limited temperature range. Our findings provide new insights into the adaptive mechanisms in plant traits in future studies.

Perception of the plant hormone ethylene: known-knowns and known-unknowns.

PubMed

Light, Kenneth M; Wisniewski, John A; Vinyard, W Andrew; Kieber-Emmons, Matthew T

2016-09-01

The gaseous phytohormone ethylene is implicated in virtually all phases of plant growth and development and thus has a major impact on crop production. This agronomic impact makes understanding ethylene signaling the Philosopher's Stone of the plant biotechnology world in applications including post-harvest transport of foodstuffs, consistency of foodstuff maturity pre-harvest, decorative flower freshness and longevity, and biomass production for biofuel applications. Ethylene is biosynthesized by plants in response to environmental factors and plant life-cycle events, and triggers a signaling cascade that modulates over 1000 genes. The key components in the perception of ethylene are a family of copper dependent receptors, the bioinorganic chemistry of which has been largely ignored by the chemical community. Since identification of these receptors two decades ago, there has been tremendous growth in knowledge in the biological community on the signal transduction pathways and mechanisms of ethylene signaling. In this review, we highlight these advances and key chemical voids in knowledge that are overdue for exploration, and which are required to ultimately regulate and control ethylene signaling.

Early warning of critical transitions in biodiversity from compositional disorder.

PubMed

Doncaster, C Patrick; Alonso Chávez, Vasthi; Viguier, Clément; Wang, Rong; Zhang, Enlou; Dong, Xuhui; Dearing, John A; Langdon, Peter G; Dyke, James G

2016-11-01

Global environmental change presents a clear need for improved leading indicators of critical transitions, especially those that can be generated from compositional data and that work in empirical cases. Ecological theory of community dynamics under environmental forcing predicts an early replacement of slowly replicating and weakly competitive "canary" species by slowly replicating but strongly competitive "keystone" species. Further forcing leads to the eventual collapse of the keystone species as they are replaced by weakly competitive but fast-replicating "weedy" species in a critical transition to a significantly different state. We identify a diagnostic signal of these changes in the coefficients of a correlation between compositional disorder and biodiversity. Compositional disorder measures unpredictability in the composition of a community, while biodiversity measures the amount of species in the community. In a stochastic simulation, sequential correlations over time switch from positive to negative as keystones prevail over canaries, and back to positive with domination of weedy species. The model finds support in empirical tests on multi-decadal time series of fossil diatom and chironomid communities from lakes in China. The characteristic switch from positive to negative correlation coefficients occurs for both communities up to three decades preceding a critical transition to a sustained alternate state. This signal is robust to unequal time increments that beset the identification of early-warning signals from other metrics. © 2016 The Authors. Ecology, published by Wiley Periodicals, Inc., on behalf of the Ecological Society of America.

City Beats: A Creative Community Partnership Initiative at ArtPlay

ERIC Educational Resources Information Center

Jeanneret, Neryl; Brown, Robert

2012-01-01

The City of Melbourne's ArtPlay is open to children and young people aged 3-13 years, and provides a wide range of artist-led programs that serve a broad community within and outside the municipality. Its sister facility, Signal, caters for young people 13-22 years. An Australia Council of the Arts funded Creative Community Partnership Initiative,…

On the recovery of missing low and high frequency information from bandlimited reflectivity data

NASA Astrophysics Data System (ADS)

Sacchi, M. D.; Ulrych, T. J.

2007-12-01

During the last two decades, an important effort in the seismic exploration community has been made to retrieve broad-band seismic data by means of deconvolution and inversion. In general, the problem can be stated as a spectral reconstruction problem. In other words, given limited spectral information about the earth's reflectivity sequence, one attempts to create a broadband estimate of the Fourier spectra of the unknown reflectivity. Techniques based on the principle of parsimony can be effectively used to retrieve a sparse spike sequence and, consequently, a broad band signal. Alternatively, continuation methods, e.g., autoregressive modeling, can be used to extrapolate the recorded bandwidth of the seismic signal. The goal of this paper is to examine under what conditions the recovery of low and high frequencies from band-limited and noisy signals is possible. At the heart of the methods we discuss, is the celebrated non-Gaussian assumption so important in many modern signal processing methods, such as ICA, for example. Spectral recovery from limited information tends to work when the reflectivity consist of a few well isolated events. Results degrade with the number of reflectors, decreasing SNR and decreasing bandwidth of the source wavelet. Constrains and information-based priors can be used to stabilize the recovery but, as in all inverse problems, the solution is nonunique and effort is required to understand the level of recovery that is achievable, always keeping the physics of the problem in mind. We provide in this paper, a survey of methods to recover broad-band reflectivity sequences and examine the role that these techniques can play in the processing and inversion as applied to exploration and global seismology.

Operational and safety efficiency of traffic signal installations.

DOT National Transportation Integrated Search

2008-05-01

The basic principle of signalization is the provision of a safe and effective means for time and space allocation at an intersection for both vehicular and pedestrian needs. The safety community concurs on the fact that there is the potential for saf...

Single-channel mixed signal blind source separation algorithm based on multiple ICA processing

NASA Astrophysics Data System (ADS)

Cheng, Xiefeng; Li, Ji

2017-01-01

Take separating the fetal heart sound signal from the mixed signal that get from the electronic stethoscope as the research background, the paper puts forward a single-channel mixed signal blind source separation algorithm based on multiple ICA processing. Firstly, according to the empirical mode decomposition (EMD), the single-channel mixed signal get multiple orthogonal signal components which are processed by ICA. The multiple independent signal components are called independent sub component of the mixed signal. Then by combining with the multiple independent sub component into single-channel mixed signal, the single-channel signal is expanded to multipath signals, which turns the under-determined blind source separation problem into a well-posed blind source separation problem. Further, the estimate signal of source signal is get by doing the ICA processing. Finally, if the separation effect is not very ideal, combined with the last time's separation effect to the single-channel mixed signal, and keep doing the ICA processing for more times until the desired estimated signal of source signal is get. The simulation results show that the algorithm has good separation effect for the single-channel mixed physiological signals.

Illuminating the Signals Job Seekers Receive from an Employer's Community Involvement and Environmental Sustainability Practices: Insights into Why Most Job Seekers Are Attracted, Others Are Indifferent, and a Few Are Repelled

PubMed Central

Jones, David A.; Willness, Chelsea R.; Heller, Kristin W.

2016-01-01

Evidence shows that job seekers tend to be attracted to employers known for their corporate social responsibility (CSR), but relatively little is known about the underlying psychological processes. Moreover, the literature is silent about whether and why some job seekers are unaffected, or even repelled by, an employer's CSR. We conducted a substantive replication of recent empirical support for three signal-based mechanisms by adapting the experimental manipulation used in a prior study while employing an alternative approach to analyzing a distinctly different type of data. We also extended prior work by examining other possible explanatory mechanisms and exploring potentially negative reactions to CSR. Using signaling theory as an overarching framework, we assessed research questions and tested hypotheses grounded in theories of employee recruitment and the psychology of CSR, specifying how an employer's CSR practices send signals from which job seekers draw inferences about unknown working conditions, thereby affecting their attraction to the employer. Study participants (N = 108) reviewed the webpages of two hiring companies and responded to open-ended questions about each employer. We content-analyzed written responses pertaining to one employer's webpages in which we embedded an experimental manipulation of information about the employer's community involvement or its environmentally sustainable practices. The results supported hypotheses that corroborate prior evidence for the “perceived value fit” and “expected employee treatment” mechanisms, and provided some, but relatively limited, support for the “anticipated pride” mechanism. Assessment of research questions highlighted previously undiscovered signal-based mechanisms that might help explain job seekers' attraction to CSR (e.g., inferences about the employer's positive work environment and financial standing, and the nature of its employees). Results also showed that a few people were less attracted because of the employer's CSR practices. Analyses among those individuals, combined with one-third of the sample who reported their attraction was unaffected by the employer's CSR, provided insights about when and why CSR fails to enhance attraction, such as when job seekers focus on other priorities, or are deeply skeptical and cynical about the employer's CSR. We discuss the implications for advancing a signal-based theory of CSR and employee recruitment, and recruitment practice. PMID:27064985

Illuminating the Signals Job Seekers Receive from an Employer's Community Involvement and Environmental Sustainability Practices: Insights into Why Most Job Seekers Are Attracted, Others Are Indifferent, and a Few Are Repelled.

PubMed

Jones, David A; Willness, Chelsea R; Heller, Kristin W

2016-01-01

Evidence shows that job seekers tend to be attracted to employers known for their corporate social responsibility (CSR), but relatively little is known about the underlying psychological processes. Moreover, the literature is silent about whether and why some job seekers are unaffected, or even repelled by, an employer's CSR. We conducted a substantive replication of recent empirical support for three signal-based mechanisms by adapting the experimental manipulation used in a prior study while employing an alternative approach to analyzing a distinctly different type of data. We also extended prior work by examining other possible explanatory mechanisms and exploring potentially negative reactions to CSR. Using signaling theory as an overarching framework, we assessed research questions and tested hypotheses grounded in theories of employee recruitment and the psychology of CSR, specifying how an employer's CSR practices send signals from which job seekers draw inferences about unknown working conditions, thereby affecting their attraction to the employer. Study participants (N = 108) reviewed the webpages of two hiring companies and responded to open-ended questions about each employer. We content-analyzed written responses pertaining to one employer's webpages in which we embedded an experimental manipulation of information about the employer's community involvement or its environmentally sustainable practices. The results supported hypotheses that corroborate prior evidence for the "perceived value fit" and "expected employee treatment" mechanisms, and provided some, but relatively limited, support for the "anticipated pride" mechanism. Assessment of research questions highlighted previously undiscovered signal-based mechanisms that might help explain job seekers' attraction to CSR (e.g., inferences about the employer's positive work environment and financial standing, and the nature of its employees). Results also showed that a few people were less attracted because of the employer's CSR practices. Analyses among those individuals, combined with one-third of the sample who reported their attraction was unaffected by the employer's CSR, provided insights about when and why CSR fails to enhance attraction, such as when job seekers focus on other priorities, or are deeply skeptical and cynical about the employer's CSR. We discuss the implications for advancing a signal-based theory of CSR and employee recruitment, and recruitment practice.

Racioethnicity, community makeup, and potential employees' reactions to organizational diversity management approaches.

PubMed

Olsen, Jesse E; Martins, Luis L

2016-05-01

We draw on the values literature from social psychology and the acculturation literature from cross-cultural psychology to develop and test a theory of how signals about an organization's diversity management (DM) approach affect perceptions of organizational attractiveness among potential employees. We examine the mediating effects of individuals' merit-based attributions about hiring decisions at the organization, as well as the moderating effects of their racioethnicity and the racioethnic composition of their home communities. We test our theory using a within-subject policy-capturing experimental design that simulates organizational DM approaches, supplemented with census data for the participants' home communities. Results of hierarchical linear modeling (HLM) analyses suggest that the manipulated instrumental value for diversity leads to higher perceptions of organizational attractiveness, in part through heightened expectations of merit-based hiring decisions. Further, the manipulated assimilative and integrative DM approach signals are positively related to organizational attractiveness and the effect of integrative DM is strongest for racioethnic minorities from communities with especially high proportions of Whites and Whites from communities with especially low proportions of Whites. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Cytobank: providing an analytics platform for community cytometry data analysis and collaboration.

PubMed

Chen, Tiffany J; Kotecha, Nikesh

2014-01-01

Cytometry is used extensively in clinical and laboratory settings to diagnose and track cell subsets in blood and tissue. High-throughput, single-cell approaches leveraging cytometry are developed and applied in the computational and systems biology communities by researchers, who seek to improve the diagnosis of human diseases, map the structures of cell signaling networks, and identify new cell types. Data analysis and management present a bottleneck in the flow of knowledge from bench to clinic. Multi-parameter flow and mass cytometry enable identification of signaling profiles of patient cell samples. Currently, this process is manual, requiring hours of work to summarize multi-dimensional data and translate these data for input into other analysis programs. In addition, the increase in the number and size of collaborative cytometry studies as well as the computational complexity of analytical tools require the ability to assemble sufficient and appropriately configured computing capacity on demand. There is a critical need for platforms that can be used by both clinical and basic researchers who routinely rely on cytometry. Recent advances provide a unique opportunity to facilitate collaboration and analysis and management of cytometry data. Specifically, advances in cloud computing and virtualization are enabling efficient use of large computing resources for analysis and backup. An example is Cytobank, a platform that allows researchers to annotate, analyze, and share results along with the underlying single-cell data.

Selective heterogeneity in exoprotease production by Bacillus subtilis.

PubMed

Davidson, Fordyce A; Seon-Yi, Chung; Stanley-Wall, Nicola R

2012-01-01

Bacteria have elaborate signalling mechanisms to ensure a behavioural response that is most likely to enhance survival in a changing environment. It is becoming increasingly apparent that as part of this response, bacteria are capable of cell differentiation and can generate multiple, mutually exclusive co-existing cell states. These cell states are often associated with multicellular processes that bring benefit to the community as a whole but which may be, paradoxically, disadvantageous to an individual subpopulation. How this process of cell differentiation is controlled is intriguing and remains a largely open question. In this paper, we consider an important aspect of cell differentiation that is known to occur in the gram-positive bacterium Bacillus subtilis: we investigate the role of two master regulators DegU and Spo0A in the control of extra-cellular protease production. Recent work in this area focussed the on role of DegU in this process and suggested that transient effects in protein production were the drivers of cell-response heterogeneity. Here, using a combination of mathematical modelling, analysis and stochastic simulations, we provide a complementary analysis of this regulatory system that investigates the roles of both DegU and Spo0A in extra-cellular protease production. In doing so, we present a mechanism for bimodality, or system heterogeneity, without the need for a bistable switch in the underlying regulatory network. Moreover, our analysis leads us to conclude that this heterogeneity is in fact a persistent, stable feature. Our results suggest that system response is divided into three zones: low and high signal levels induce a unimodal or undifferentiated response from the cell population with all cells OFF and ON, respectively for exoprotease production. However, for intermediate levels of signal, a heterogeneous response is predicted with a spread of activity levels, representing typical "bet-hedging" behaviour.

Opposing assembly mechanisms in a neotropical dry forest: implications for phylogenetic and functional community ecology.

PubMed

Swenson, Nathan G; Enquist, Brian J

2009-08-01

Species diversity is promoted and maintained by ecological and evolutionary processes operating on species attributes through space and time. The degree to which variability in species function regulates distribution and promotes coexistence of species has been debated. Previous work has attempted to quantify the relative importance of species function by using phylogenetic relatedness as a proxy for functional similarity. The key assumption of this approach is that function is phylogenetically conserved. If this assumption is supported, then the phylogenetic dispersion in a community should mirror the functional dispersion. Here we quantify functional trait dispersion along several key axes of tree life-history variation and on multiple spatial scales in a Neotropical dry-forest community. We next compare these results to previously reported patterns of phylogenetic dispersion in this same forest. We find that, at small spatial scales, coexisting species are typically more functionally clustered than expected, but traits related to adult and regeneration niches are overdispersed. This outcome was repeated when the analyses were stratified by size class. Some of the trait dispersion results stand in contrast to the previously reported phylogenetic dispersion results. In order to address this inconsistency we examined the strength of phylogenetic signal in traits at different depths in the phylogeny. We argue that: (1) while phylogenetic relatedness may be a good general multivariate proxy for ecological similarity, it may have a reduced capacity to depict the functional mechanisms behind species coexistence when coexisting species simultaneously converge and diverge in function; and (2) the previously used metric of phylogenetic signal provided erroneous inferences about trait dispersion when married with patterns of phylogenetic dispersion.

Assessing the continuum of applications and societal benefits of US CLIVAR science

NASA Astrophysics Data System (ADS)

Ray, A. J.; Garfin, G. M.

2015-12-01

The new US CLIVAR strategic plan seeks to address the challenges of communicating the climate knowledge generated through its activities and to collaborate with the research and operational communities that may use this knowledge for managing climate risks. This presentation provides results of an overview in progress of the continuum of potential applications of climate science organized and coordinated through US CLIVAR. We define applications more broadly than simply ready for operations or direct use, and find that there are several stages in a continuum of readiness for communication and collaboration with communities that use climate information. These stages include: 1) advancing scientific understanding to a readiness for the next research steps aimed at predictable signals; 2) application of understanding climate phenomena in collaboration with a boundary organization, such as NOAA RISAs DOI Climate Science Centers, and USDA Climate Hubs, to understand how predictable signals may be translated into useable products; 3) use of knowledge in risk framing for a decision process, or in a science synthesis, such as the National Climate Assessment, and 4) transitioning new science knowledge into operational products (e.g. R2O), such as intraseasonal climate prediction. In addition, US CLIVAR has sponsored efforts to build science-to-decisions capacity, e.g., the Postdocs Applying Climate Expertise (PACE) program, in its 7th cohort, which has embedded climate experts into decision-making institutions. We will spotlight accomplishments of US CLIVAR science that are ripe for application in communities that are managing climate risks -- such as drought outlooks, MJO forecasting, extremes, and ocean conditions -- for agricultural production, water use, and marine ecosystems. We will use these examples to demonstrate the usefulness of an "applications continuum framework" identifying pathways from research to applications.

GPS Technologies as a Tool to Detect the Pre-Earthquake Signals Associated with Strong Earthquakes

NASA Astrophysics Data System (ADS)

Pulinets, S. A.; Krankowski, A.; Hernandez-Pajares, M.; Liu, J. Y. G.; Hattori, K.; Davidenko, D.; Ouzounov, D.

2015-12-01

The existence of ionospheric anomalies before earthquakes is now widely accepted. These phenomena started to be considered by GPS community to mitigate the GPS signal degradation over the territories of the earthquake preparation. The question is still open if they could be useful for seismology and for short-term earthquake forecast. More than decade of intensive studies proved that ionospheric anomalies registered before earthquakes are initiated by processes in the boundary layer of atmosphere over earthquake preparation zone and are induced in the ionosphere by electromagnetic coupling through the Global Electric Circuit. Multiparameter approach based on the Lithosphere-Atmosphere-Ionosphere Coupling model demonstrated that earthquake forecast is possible only if we consider the final stage of earthquake preparation in the multidimensional space where every dimension is one from many precursors in ensemble, and they are synergistically connected. We demonstrate approaches developed in different countries (Russia, Taiwan, Japan, Spain, and Poland) within the framework of the ISSI and ESA projects) to identify the ionospheric precursors. They are also useful to determine the all three parameters necessary for the earthquake forecast: impending earthquake epicenter position, expectation time and magnitude. These parameters are calculated using different technologies of GPS signal processing: time series, correlation, spectral analysis, ionospheric tomography, wave propagation, etc. Obtained results from different teams demonstrate the high level of statistical significance and physical justification what gives us reason to suggest these methodologies for practical validation.

Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways.

PubMed

Becnel, Lauren B; Darlington, Yolanda F; Ochsner, Scott A; Easton-Marks, Jeremy R; Watkins, Christopher M; McOwiti, Apollo; Kankanamge, Wasula H; Wise, Michael W; DeHart, Michael; Margolis, Ronald N; McKenna, Neil J

2015-01-01

Signaling pathways involving nuclear receptors (NRs), their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA) is a Consortium focused around a Hub website (www.nursa.org) that annotates and integrates diverse 'omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs). These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy "Web 2.0" technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA's Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field.

Critical slowing down as early warning for the onset of collapse in mutualistic communities.

PubMed

Dakos, Vasilis; Bascompte, Jordi

2014-12-09

Tipping points are crossed when small changes in external conditions cause abrupt unexpected responses in the current state of a system. In the case of ecological communities under stress, the risk of approaching a tipping point is unknown, but its stakes are high. Here, we test recently developed critical slowing-down indicators as early-warning signals for detecting the proximity to a potential tipping point in structurally complex ecological communities. We use the structure of 79 empirical mutualistic networks to simulate a scenario of gradual environmental change that leads to an abrupt first extinction event followed by a sequence of species losses until the point of complete community collapse. We find that critical slowing-down indicators derived from time series of biomasses measured at the species and community level signal the proximity to the onset of community collapse. In particular, we identify specialist species as likely the best-indicator species for monitoring the proximity of a community to collapse. In addition, trends in slowing-down indicators are strongly correlated to the timing of species extinctions. This correlation offers a promising way for mapping species resilience and ranking species risk to extinction in a given community. Our findings pave the road for combining theory on tipping points with patterns of network structure that might prove useful for the management of a broad class of ecological networks under global environmental change.

FPGA-Based Filterbank Implementation for Parallel Digital Signal Processing

NASA Technical Reports Server (NTRS)

Berner, Stephan; DeLeon, Phillip

1999-01-01

One approach to parallel digital signal processing decomposes a high bandwidth signal into multiple lower bandwidth (rate) signals by an analysis bank. After processing, the subband signals are recombined into a fullband output signal by a synthesis bank. This paper describes an implementation of the analysis and synthesis banks using (Field Programmable Gate Arrays) FPGAs.

A survey of signal processing algorithms in brain-computer interfaces based on electrical brain signals.

PubMed

Bashashati, Ali; Fatourechi, Mehrdad; Ward, Rabab K; Birch, Gary E

2007-06-01

Brain-computer interfaces (BCIs) aim at providing a non-muscular channel for sending commands to the external world using the electroencephalographic activity or other electrophysiological measures of the brain function. An essential factor in the successful operation of BCI systems is the methods used to process the brain signals. In the BCI literature, however, there is no comprehensive review of the signal processing techniques used. This work presents the first such comprehensive survey of all BCI designs using electrical signal recordings published prior to January 2006. Detailed results from this survey are presented and discussed. The following key research questions are addressed: (1) what are the key signal processing components of a BCI, (2) what signal processing algorithms have been used in BCIs and (3) which signal processing techniques have received more attention?

TOPICAL REVIEW: A survey of signal processing algorithms in brain computer interfaces based on electrical brain signals

NASA Astrophysics Data System (ADS)

Bashashati, Ali; Fatourechi, Mehrdad; Ward, Rabab K.; Birch, Gary E.

2007-06-01

Brain computer interfaces (BCIs) aim at providing a non-muscular channel for sending commands to the external world using the electroencephalographic activity or other electrophysiological measures of the brain function. An essential factor in the successful operation of BCI systems is the methods used to process the brain signals. In the BCI literature, however, there is no comprehensive review of the signal processing techniques used. This work presents the first such comprehensive survey of all BCI designs using electrical signal recordings published prior to January 2006. Detailed results from this survey are presented and discussed. The following key research questions are addressed: (1) what are the key signal processing components of a BCI, (2) what signal processing algorithms have been used in BCIs and (3) which signal processing techniques have received more attention?

Reusable software parts and the semi-abstract data type

NASA Technical Reports Server (NTRS)

Cohen, Sanford G.

1986-01-01

The development of reuable software parts has been an area of intense discussion within the software community for many years. An approach is described for developing reusable parts for the applications of missile guidance, navigation and control which meet the following criteria: (1) Reusable; (2) Tailorable; (3) Efficient; (4) Simple to use; and (5) Protected against misuse. Validating the feasibility of developing reusable parts which possess these characteristics is the basis of the Common Ada Missile Packages Program (CAMP). Under CAMP, over 200 reusable software parts were developed, including part for navigation, Kalman filter, signal processing and autopilot. Six different methods are presented for designing reusable software parts.

NASA's Aeroacoustic Tools and Methods for Analysis of Aircraft Noise

NASA Technical Reports Server (NTRS)

Rizzi, Stephen A.; Lopes, Leonard V.; Burley, Casey L.

2015-01-01

Aircraft community noise is a significant concern due to continued growth in air traffic, increasingly stringent environmental goals, and operational limitations imposed by airport authorities. The ability to quantify aircraft noise at the source and ultimately at observers is required to develop low noise aircraft designs and flight procedures. Predicting noise at the source, accounting for scattering and propagation through the atmosphere to the observer, and assessing the perception and impact on a community requires physics-based aeroacoustics tools. Along with the analyses for aero-performance, weights and fuel burn, these tools can provide the acoustic component for aircraft MDAO (Multidisciplinary Design Analysis and Optimization). Over the last decade significant progress has been made in advancing the aeroacoustic tools such that acoustic analyses can now be performed during the design process. One major and enabling advance has been the development of the system noise framework known as Aircraft NOise Prediction Program2 (ANOPP2). ANOPP2 is NASA's aeroacoustic toolset and is designed to facilitate the combination of acoustic approaches of varying fidelity for the analysis of noise from conventional and unconventional aircraft. The toolset includes a framework that integrates noise prediction and propagation methods into a unified system for use within general aircraft analysis software. This includes acoustic analyses, signal processing and interfaces that allow for the assessment of perception of noise on a community. ANOPP2's capability to incorporate medium fidelity shielding predictions and wind tunnel experiments into a design environment is presented. An assessment of noise from a conventional and Hybrid Wing Body (HWB) aircraft using medium fidelity scattering methods combined with noise measurements from a model-scale HWB recently placed in NASA's 14x22 wind tunnel are presented. The results are in the form of community noise metrics and auralizations.

Comprehensive evaluation on transit signal priority system impacts using field observed traffic data

DOT National Transportation Integrated Search

2007-06-15

To improve the level of service for Community Transit (CT) buses, the South Snohomish Regional Transit Signal Priority (SS-RTSP) project has been launched. To understand the overall benefit of this project, the SS-RTSP system was tested and evaluated...

Is complex signal processing for bone conduction hearing aids useful?

PubMed

Kompis, Martin; Kurz, Anja; Pfiffner, Flurin; Senn, Pascal; Arnold, Andreas; Caversaccio, Marco

2014-05-01

To establish whether complex signal processing is beneficial for users of bone anchored hearing aids. Review and analysis of two studies from our own group, each comparing a speech processor with basic digital signal processing (either Baha Divino or Baha Intenso) and a processor with complex digital signal processing (either Baha BP100 or Baha BP110 power). The main differences between basic and complex signal processing are the number of audiologist accessible frequency channels and the availability and complexity of the directional multi-microphone noise reduction and loudness compression systems. Both studies show a small, statistically non-significant improvement of speech understanding in quiet with the complex digital signal processing. The average improvement for speech in noise is +0.9 dB, if speech and noise are emitted both from the front of the listener. If noise is emitted from the rear and speech from the front of the listener, the advantage of the devices with complex digital signal processing as opposed to those with basic signal processing increases, on average, to +3.2 dB (range +2.3 … +5.1 dB, p ≤ 0.0032). Complex digital signal processing does indeed improve speech understanding, especially in noise coming from the rear. This finding has been supported by another study, which has been published recently by a different research group. When compared to basic digital signal processing, complex digital signal processing can increase speech understanding of users of bone anchored hearing aids. The benefit is most significant for speech understanding in noise.

Digital Signal Processing Based Biotelemetry Receivers

NASA Technical Reports Server (NTRS)

Singh, Avtar; Hines, John; Somps, Chris

1997-01-01

This is an attempt to develop a biotelemetry receiver using digital signal processing technology and techniques. The receiver developed in this work is based on recovering signals that have been encoded using either Pulse Position Modulation (PPM) or Pulse Code Modulation (PCM) technique. A prototype has been developed using state-of-the-art digital signal processing technology. A Printed Circuit Board (PCB) is being developed based on the technique and technology described here. This board is intended to be used in the UCSF Fetal Monitoring system developed at NASA. The board is capable of handling a variety of PPM and PCM signals encoding signals such as ECG, temperature, and pressure. A signal processing program has also been developed to analyze the received ECG signal to determine heart rate. This system provides a base for using digital signal processing in biotelemetry receivers and other similar applications.

Signal processing techniques for damage detection with piezoelectric wafer active sensors and embedded ultrasonic structural radar

NASA Astrophysics Data System (ADS)

Yu, Lingyu; Bao, Jingjing; Giurgiutiu, Victor

2004-07-01

Embedded ultrasonic structural radar (EUSR) algorithm is developed for using piezoelectric wafer active sensor (PWAS) array to detect defects within a large area of a thin-plate specimen. Signal processing techniques are used to extract the time of flight of the wave packages, and thereby to determine the location of the defects with the EUSR algorithm. In our research, the transient tone-burst wave propagation signals are generated and collected by the embedded PWAS. Then, with signal processing, the frequency contents of the signals and the time of flight of individual frequencies are determined. This paper starts with an introduction of embedded ultrasonic structural radar algorithm. Then we will describe the signal processing methods used to extract the time of flight of the wave packages. The signal processing methods being used include the wavelet denoising, the cross correlation, and Hilbert transform. Though hardware device can provide averaging function to eliminate the noise coming from the signal collection process, wavelet denoising is included to ensure better signal quality for the application in real severe environment. For better recognition of time of flight, cross correlation method is used. Hilbert transform is applied to the signals after cross correlation in order to extract the envelope of the signals. Signal processing and EUSR are both implemented by developing a graphical user-friendly interface program in LabView. We conclude with a description of our vision for applying EUSR signal analysis to structural health monitoring and embedded nondestructive evaluation. To this end, we envisage an automatic damage detection application utilizing embedded PWAS, EUSR, and advanced signal processing.

Device and method to enhance availability of cluster-based processing systems

NASA Technical Reports Server (NTRS)

Lupia, David J. (Inventor); Ramos, Jeremy (Inventor); Samson, Jr., John R. (Inventor)

2010-01-01

An electronic computing device including at least one processing unit that implements a specific fault signal upon experiencing an associated fault, a control unit that generates a specific recovery signal upon receiving the fault signal from the at least one processing unit, and at least one input memory unit. The recovery signal initiates specific recovery processes in the at least one processing unit. The input memory buffers input data signals input to the at least one processing unit that experienced the fault during the recovery period.

Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology

PubMed Central

2017-01-01

ABSTRACT Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, Bacillus subtilis and Streptomyces sp. strain Mg1. Using this model, we previously found that linearmycins produced by Streptomyces sp. strain Mg1 cause lysis of B. subtilis cells and degradation of colony matrix. We identified strains of B. subtilis with mutations in the two-component signaling system yfiJK operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter yfiLMN operon, particularly yfiM and yfiN, is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of B. subtilis. IMPORTANCE DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches. PMID:28461449

Microbial community diversity of the eastern Atlantic Ocean reveals geographic differences

NASA Astrophysics Data System (ADS)

Friedline, C. J.; Franklin, R. B.; McCallister, S. L.; Rivera, M. C.

2012-01-01

Prokaryotic communities are recognized as major drivers of the biogeochemical processes in the oceans. However, the genetic diversity and composition of those communities is poorly understood. The aim of this study was to investigate the eubacterial communities in three different water layers: surface (2-20 m), deep chlorophyll maximum (DCM; 28-90 m), and deep (100-4600 m) at nine stations along the eastern Atlantic Ocean from 42.8° N to 23.7° S. In order to describe the dynamics of the eubacterial assemblages in relation to depth, associated environmental properties, and Longhurstian ecological provinces community DNA was extracted from 16 samples, from which the V6 region of 16s rDNA was PCR-amplified with eubacteria-specific primers, and the PCR amplicons were pyrosequenced. A total of 352 029 sequences were generated; after quality filtering and processing, 257 260 sequences were clustered into 2871 normalized Operational Taxonomic Units (OTU) using a definition of 97% sequence identity. Comparisons of the phylogenetic affiliation of those 2871 OTUs show more than 54% of them were assigned to the Proteobacteria, with the Alphaproteobacteria representing 4% of the total Proteobacteria OTUs, and the Gammaproteobacteria representing 22%. Within the Alphaproteobacteria-affiliated OTUs, 44% of the OTUs were associated with the ubiquitous SAR11 clade. The phylum Cyanobacteria represent 10% of the reads, with the majority of those reads among the GpIIa family including Prochlorococcus and Synechococcus. Among the Gammaproteobacteria, a single OTU affiliated to Alteromonas comprises ~3% of the abundance. The phyla Bacteroidetes, Verrucomicrobia, Actinobacteria, and Firmicutes represent approximately 7%, 0.8%, 2%, and 0.05% of the read abundance, respectively. Community ecology statistical analyses and a novel implementation of Bayesian inference suggests that eastern Atlantic Ocean eubacterial assemblages are vertically stratified and associated with water layers characterized by unique environmental signals (e.g., temperature, salinity, and nutrients). Genetic composition of eubacterial communities from the same water layer are more similar to each other than to the communities from different water layers. Moreover, within the same water layer the separation of the communities appears to show a significant distance effect. Surface eubacterial communities displayed a general congruency with the ecological provinces defined by Longhurst with exceptions usually associated with unique hydrographic and biogeochemical features. Collectively, our findings suggest that a vertical and latitudinal biogeographical signature is present in the studied communities and that both environmental parameters and ecological provinces are drivers of eubacterial assemblages in the eastern Atlantic Ocean.

COMMUNITY STRESS, DEMORALIZATION AND BODY MASS INDEX: EVIDENCE FOR SOCIAL SIGNAL TRANSDUCTION. (R827027)

EPA Science Inventory

Quantification of the relationship between community-level chronic stress from neighborhood conditions and individual morale has rarely been reported. In this work, pregnant women were recruited at the prenatal clinics of Harlem Hospital and Columbia Presbyterian Medical Cente...

An Initial Evaluation of Siting Considerations on Current and Future Wind Deployment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tegen, Suzanne; Lantz, Eric; Mai, Trieu

This report provides a deeper understanding of the wind project development process, from desktop studies to a successful project in the ground. It examines three siting consideration categories that wind project sponsors must include in the development process: wildlife (species that live in, near, or migrate through the area where wind development is possible), radar (wind turbines can cause interference with radar signals), and public engagement (representing communities and stakeholders who live near wind power projects). The research shows that although this country's abundant wind resource provides numerous options for addressing siting considerations, actually siting individual projects is becoming moremore » difficult because of regulatory and other uncertainties. Model results are based on the premise that developers will be able to site, permit, and build successful projects, which is not always the case in reality.« less

Beyond the continuum: a multi-dimensional phase space for neutral-niche community assembly.

PubMed

Latombe, Guillaume; Hui, Cang; McGeoch, Melodie A

2015-12-22

Neutral and niche processes are generally considered to interact in natural communities along a continuum, exhibiting community patterns bounded by pure neutral and pure niche processes. The continuum concept uses niche separation, an attribute of the community, to test the hypothesis that communities are bounded by pure niche or pure neutral conditions. It does not accommodate interactions via feedback between processes and the environment. By contrast, we introduce the Community Assembly Phase Space (CAPS), a multi-dimensional space that uses community processes (such as dispersal and niche selection) to define the limiting neutral and niche conditions and to test the continuum hypothesis. We compare the outputs of modelled communities in a heterogeneous landscape, assembled by pure neutral, pure niche and composite processes. Differences in patterns under different combinations of processes in CAPS reveal hidden complexity in neutral-niche community dynamics. The neutral-niche continuum only holds for strong dispersal limitation and niche separation. For weaker dispersal limitation and niche separation, neutral and niche processes amplify each other via feedback with the environment. This generates patterns that lie well beyond those predicted by a continuum. Inferences drawn from patterns about community assembly processes can therefore be misguided when based on the continuum perspective. CAPS also demonstrates the complementary information value of different patterns for inferring community processes and captures the complexity of community assembly. It provides a general tool for studying the processes structuring communities and can be applied to address a range of questions in community and metacommunity ecology. © 2015 The Author(s).

Beyond the continuum: a multi-dimensional phase space for neutral–niche community assembly

PubMed Central

Latombe, Guillaume; McGeoch, Melodie A.

2015-01-01

Neutral and niche processes are generally considered to interact in natural communities along a continuum, exhibiting community patterns bounded by pure neutral and pure niche processes. The continuum concept uses niche separation, an attribute of the community, to test the hypothesis that communities are bounded by pure niche or pure neutral conditions. It does not accommodate interactions via feedback between processes and the environment. By contrast, we introduce the Community Assembly Phase Space (CAPS), a multi-dimensional space that uses community processes (such as dispersal and niche selection) to define the limiting neutral and niche conditions and to test the continuum hypothesis. We compare the outputs of modelled communities in a heterogeneous landscape, assembled by pure neutral, pure niche and composite processes. Differences in patterns under different combinations of processes in CAPS reveal hidden complexity in neutral–niche community dynamics. The neutral–niche continuum only holds for strong dispersal limitation and niche separation. For weaker dispersal limitation and niche separation, neutral and niche processes amplify each other via feedback with the environment. This generates patterns that lie well beyond those predicted by a continuum. Inferences drawn from patterns about community assembly processes can therefore be misguided when based on the continuum perspective. CAPS also demonstrates the complementary information value of different patterns for inferring community processes and captures the complexity of community assembly. It provides a general tool for studying the processes structuring communities and can be applied to address a range of questions in community and metacommunity ecology. PMID:26702047

Paranoia Symptoms Moderate the Impact of Emotional Context Processing on Community Functioning of Individuals with Schizophrenia.

PubMed

Park, Kiho; Choi, Kee-Hong

2018-04-26

This study examined whether better emotional context processing is associated with better community functioning among persons with schizophrenia, and whether the relationship between the two variables is moderated by level of paranoid symptoms. The Brief Psychiatric Rating Scale-Expanded Version, Emotional Context Processing Scale, and Multnomah Community Ability Scale were administered to 39 community-dwelling participants with schizophrenia or schizoaffective disorder. Emotional context processing had a small-to-moderate association with community functioning. However, the association between emotional context processing and community functioning was moderated by level of paranoid symptoms. Emotional context processing in participants with mild paranoid symptoms was strongly associated with better community functioning, whereas emotional context processing in those with severe paranoid symptoms was not. Emotional context processing and the degree of paranoia should be considered in treatment plans designed to enhance the community functioning of individuals with schizophrenia to help them improve their understanding of social situations.

System and method for investigating sub-surface features of a rock formation with acoustic sources generating coded signals

DOEpatents

Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

2014-12-30

A system and a method for investigating rock formations includes generating, by a first acoustic source, a first acoustic signal comprising a first plurality of pulses, each pulse including a first modulated signal at a central frequency; and generating, by a second acoustic source, a second acoustic signal comprising a second plurality of pulses. A receiver arranged within the borehole receives a detected signal including a signal being generated by a non-linear mixing process from the first-and-second acoustic signal in a non-linear mixing zone within the intersection volume. The method also includes-processing the received signal to extract the signal generated by the non-linear mixing process over noise or over signals generated by a linear interaction process, or both.

Vulnerability and adaptation to severe weather events in the American southwest

DOE PAGES

Boero, Riccardo; Bianchini, Laura; Pasqualini, Donatella

2015-05-04

Climate change can induce changes in the frequency of severe weather events representing a threat to socio-economic development. It is thus of uttermost importance to understand how the vulnerability to the weather of local communities is determined and how adaptation public policies can be effectively put in place. We focused our empirical analysis on the American Southwest. Results show that, consistently with the predictions of an investment model, economic characteristics signaling local economic growth in the near future decrease the level of vulnerability. We also show that federal governments transfers and grants neither work to support recovery from and adaptationmore » to weather events nor to distribute their costs over a broader tax base. Finally, we show that communities relying on municipal bonds to finance adaptation and recovery policies can benefit from local acknowledgment of the need for such policies and that they do not have to pay lenders a premium for the risk induced by weather events. In conclusion, our findings suggest that determinants of economic growth support lower vulnerability to the weather and increase options for financing adaptation and recovery policies, but also that only some communities are likely to benefit from those processes.« less

Vulnerability and adaptation to severe weather events in the American southwest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boero, Riccardo; Bianchini, Laura; Pasqualini, Donatella

Climate change can induce changes in the frequency of severe weather events representing a threat to socio-economic development. It is thus of uttermost importance to understand how the vulnerability to the weather of local communities is determined and how adaptation public policies can be effectively put in place. We focused our empirical analysis on the American Southwest. Results show that, consistently with the predictions of an investment model, economic characteristics signaling local economic growth in the near future decrease the level of vulnerability. We also show that federal governments transfers and grants neither work to support recovery from and adaptationmore » to weather events nor to distribute their costs over a broader tax base. Finally, we show that communities relying on municipal bonds to finance adaptation and recovery policies can benefit from local acknowledgment of the need for such policies and that they do not have to pay lenders a premium for the risk induced by weather events. In conclusion, our findings suggest that determinants of economic growth support lower vulnerability to the weather and increase options for financing adaptation and recovery policies, but also that only some communities are likely to benefit from those processes.« less

Intelligent processing of acoustic emission signals

NASA Astrophysics Data System (ADS)

Sachse, Wolfgang; Grabec, Igor

1992-07-01

Recent developments in applying neural-like signal-processing procedures for analyzing acoustic emission signals are summarized. These procedures employ a set of learning signals to develop a memory that can subsequently be utilized to process other signals to recover information about an unknown source. A majority of the current applications to process ultrasonic waveforms are based on multilayered, feed-forward neural networks, trained with some type of back-error propagation rule.

Comprehensive evaluation on transit signal priority system impacts using field observed traffic data (Phase One)

DOT National Transportation Integrated Search

2006-08-01

To improve the level of Community Transit (CT) services, the South Snohomish Regional Transit Signal Priority (SS-RTSP) project has been launched. To understand the overall benefit of this project, the SS-RTSP system (phase one) was tested and evalua...

Mechanistic links between gut microbial community dynamics, microbial functions and metabolic health.

PubMed

Ha, Connie W Y; Lam, Yan Y; Holmes, Andrew J

2014-11-28

Gut microbes comprise a high density, biologically active community that lies at the interface of an animal with its nutritional environment. Consequently their activity profoundly influences many aspects of the physiology and metabolism of the host animal. A range of microbial structural components and metabolites directly interact with host intestinal cells and tissues to influence nutrient uptake and epithelial health. Endocrine, neuronal and lymphoid cells in the gut also integrate signals from these microbial factors to influence systemic responses. Dysregulation of these host-microbe interactions is now recognised as a major risk factor in the development of metabolic dysfunction. This is a two-way process and understanding the factors that tip host-microbiome homeostasis over to dysbiosis requires greater appreciation of the host feedbacks that contribute to regulation of microbial community composition. To date, numerous studies have employed taxonomic profiling approaches to explore the links between microbial composition and host outcomes (especially obesity and its comorbidities), but inconsistent host-microbe associations have been reported. Available data indicates multiple factors have contributed to discrepancies between studies. These include the high level of functional redundancy in host-microbiome interactions combined with individual variation in microbiome composition; differences in study design, diet composition and host system between studies; and inherent limitations to the resolution of rRNA-based community profiling. Accounting for these factors allows for recognition of the common microbial and host factors driving community composition and development of dysbiosis on high fat diets. New therapeutic intervention options are now emerging.

Mechanistic links between gut microbial community dynamics, microbial functions and metabolic health

PubMed Central

Ha, Connie WY; Lam, Yan Y; Holmes, Andrew J

2014-01-01

Gut microbes comprise a high density, biologically active community that lies at the interface of an animal with its nutritional environment. Consequently their activity profoundly influences many aspects of the physiology and metabolism of the host animal. A range of microbial structural components and metabolites directly interact with host intestinal cells and tissues to influence nutrient uptake and epithelial health. Endocrine, neuronal and lymphoid cells in the gut also integrate signals from these microbial factors to influence systemic responses. Dysregulation of these host-microbe interactions is now recognised as a major risk factor in the development of metabolic dysfunction. This is a two-way process and understanding the factors that tip host-microbiome homeostasis over to dysbiosis requires greater appreciation of the host feedbacks that contribute to regulation of microbial community composition. To date, numerous studies have employed taxonomic profiling approaches to explore the links between microbial composition and host outcomes (especially obesity and its comorbidities), but inconsistent host-microbe associations have been reported. Available data indicates multiple factors have contributed to discrepancies between studies. These include the high level of functional redundancy in host-microbiome interactions combined with individual variation in microbiome composition; differences in study design, diet composition and host system between studies; and inherent limitations to the resolution of rRNA-based community profiling. Accounting for these factors allows for recognition of the common microbial and host factors driving community composition and development of dysbiosis on high fat diets. New therapeutic intervention options are now emerging. PMID:25469018

Determining Aliasing in Isolated Signal Conditioning Modules

NASA Technical Reports Server (NTRS)

2009-01-01

The basic concept of aliasing is this: Converting analog data into digital data requires sampling the signal at a specific rate, known as the sampling frequency. The result of this conversion process is a new function, which is a sequence of digital samples. This new function has a frequency spectrum, which contains all the frequency components of the original signal. The Fourier transform mathematics of this process show that the frequency spectrum of the sequence of digital samples consists of the original signal s frequency spectrum plus the spectrum shifted by all the harmonics of the sampling frequency. If the original analog signal is sampled in the conversion process at a minimum of twice the highest frequency component contained in the analog signal, and if the reconstruction process is limited to the highest frequency of the original signal, then the reconstructed signal accurately duplicates the original analog signal. It is this process that can give birth to aliasing.

A lithospheric magnetic field model derived from the Swarm satellite magnetic field measurements

NASA Astrophysics Data System (ADS)

Hulot, G.; Thebault, E.; Vigneron, P.

2015-12-01

The Swarm constellation of satellites was launched in November 2013 and has since then delivered high quality scalar and vector magnetic field measurements. A consortium of several research institutions was selected by the European Space Agency (ESA) to provide a number of scientific products which will be made available to the scientific community. Within this framework, specific tools were tailor-made to better extract the magnetic signal emanating from Earth's the lithospheric. These tools rely on the scalar gradient measured by the lower pair of Swarm satellites and rely on a regional modeling scheme that is more sensitive to small spatial scales and weak signals than the standard spherical harmonic modeling. In this presentation, we report on various activities related to data analysis and processing. We assess the efficiency of this dedicated chain for modeling the lithospheric magnetic field using more than one year of measurements, and finally discuss refinements that are continuously implemented in order to further improve the robustness and the spatial resolution of the lithospheric field model.

Quantifying a Total Non-Methane Hydrocarbon Signal using Low-Cost VOC Sensors in an Effort to Help Communities Learn More About their Air Quality

NASA Astrophysics Data System (ADS)

Collier, A. M.; Hannigan, M.; Piedrahita, R.; Casey, J. G.; Johnston, J.; Chiang, S.

2016-12-01

The growing accessibility of low-cost air quality monitoring technologies has led to their increased usage among community-based organizations, particularly for the monitoring of pollutants dangerous to human health (e.g., hazardous air pollutants or HAPS). However, often these low-cost sensors are `off-the-shelf' and are being utilized in a manner that differs from their intended purpose - necessitating high quality calibrations. For example, VOC sensors intended for the detection of high levels of a particular compound in an industrial setting may instead be used for ambient monitoring of a group of VOCs. Academic/community partnerships can be an ideal way to improve this type of sensor quantification while providing a community with not only the opportunity to use these technologies with additional support around data quality, but also the opportunity for education around the abilities and applications of low-cost sensors. In the spring of 2016, our lab at the University of Colorado, Boulder partnered with communities in Los Angeles and Kern County to deploy low-cost air quality monitors for the purpose of quantifying methane and non-methane hydrocarbon signals in an effort to learn more about potential impacts from local sources (e.g., nearby highways and oil & gas development). The monitoring platform was developed in our lab and is capable of logging multiple gas phase species as well as some environmental parameters. The monitors include two different metal oxide VOC sensors - each with slightly different sensing capabilities. Calibration was achieved using a pre- and post-deployment field normalization to reference monitoring equipment maintained by the South Coast Air Quality Management District. Monitors were then deployed at locations throughout the community. We will present results on our efforts to quantify a total non-methane hydrocarbon signal, observations from the field data, and recommendations for academic/community partnerships formed around air quality monitoring.

Poisson pre-processing of nonstationary photonic signals: Signals with equality between mean and variance.

PubMed

Poplová, Michaela; Sovka, Pavel; Cifra, Michal

2017-01-01

Photonic signals are broadly exploited in communication and sensing and they typically exhibit Poisson-like statistics. In a common scenario where the intensity of the photonic signals is low and one needs to remove a nonstationary trend of the signals for any further analysis, one faces an obstacle: due to the dependence between the mean and variance typical for a Poisson-like process, information about the trend remains in the variance even after the trend has been subtracted, possibly yielding artifactual results in further analyses. Commonly available detrending or normalizing methods cannot cope with this issue. To alleviate this issue we developed a suitable pre-processing method for the signals that originate from a Poisson-like process. In this paper, a Poisson pre-processing method for nonstationary time series with Poisson distribution is developed and tested on computer-generated model data and experimental data of chemiluminescence from human neutrophils and mung seeds. The presented method transforms a nonstationary Poisson signal into a stationary signal with a Poisson distribution while preserving the type of photocount distribution and phase-space structure of the signal. The importance of the suggested pre-processing method is shown in Fano factor and Hurst exponent analysis of both computer-generated model signals and experimental photonic signals. It is demonstrated that our pre-processing method is superior to standard detrending-based methods whenever further signal analysis is sensitive to variance of the signal.

Poisson pre-processing of nonstationary photonic signals: Signals with equality between mean and variance

PubMed Central

Poplová, Michaela; Sovka, Pavel

2017-01-01

Photonic signals are broadly exploited in communication and sensing and they typically exhibit Poisson-like statistics. In a common scenario where the intensity of the photonic signals is low and one needs to remove a nonstationary trend of the signals for any further analysis, one faces an obstacle: due to the dependence between the mean and variance typical for a Poisson-like process, information about the trend remains in the variance even after the trend has been subtracted, possibly yielding artifactual results in further analyses. Commonly available detrending or normalizing methods cannot cope with this issue. To alleviate this issue we developed a suitable pre-processing method for the signals that originate from a Poisson-like process. In this paper, a Poisson pre-processing method for nonstationary time series with Poisson distribution is developed and tested on computer-generated model data and experimental data of chemiluminescence from human neutrophils and mung seeds. The presented method transforms a nonstationary Poisson signal into a stationary signal with a Poisson distribution while preserving the type of photocount distribution and phase-space structure of the signal. The importance of the suggested pre-processing method is shown in Fano factor and Hurst exponent analysis of both computer-generated model signals and experimental photonic signals. It is demonstrated that our pre-processing method is superior to standard detrending-based methods whenever further signal analysis is sensitive to variance of the signal. PMID:29216207

Informational approach to the analysis of acoustic signals

NASA Astrophysics Data System (ADS)

Senkevich, Yuriy; Dyuk, Vyacheslav; Mishchenko, Mikhail; Solodchuk, Alexandra

2017-10-01

The example of linguistic processing of acoustic signals of a seismic event would be an information approach to the processing of non-stationary signals. The method for converting an acoustic signal into an information message is described by identifying repetitive self-similar patterns. The definitions of the event selection indicators in the symbolic recording of the acoustic signal are given. The results of processing an acoustic signal by a computer program realizing the processing of linguistic data are shown. Advantages and disadvantages of using software algorithms are indicated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polese, Luigi Gentile; Brackney, Larry

An image-based occupancy sensor includes a motion detection module that receives and processes an image signal to generate a motion detection signal, a people detection module that receives the image signal and processes the image signal to generate a people detection signal, a face detection module that receives the image signal and processes the image signal to generate a face detection signal, and a sensor integration module that receives the motion detection signal from the motion detection module, receives the people detection signal from the people detection module, receives the face detection signal from the face detection module, and generatesmore » an occupancy signal using the motion detection signal, the people detection signal, and the face detection signal, with the occupancy signal indicating vacancy or occupancy, with an occupancy indication specifying that one or more people are detected within the monitored volume.« less

Missed opportunities in primary care: the importance of identifying depression through screening, family history, and chronic disease management.

PubMed

Maradiegue, Ann H; Khan, Fakiha

2013-02-01

This study explored the adequacy of depression screening in a community health center. The medical charts of individuals (N = 90) enrolled at a community health center were randomly selected, reviewed, and compared to current standard-of-care guidelines for four elements: family history, screening for depression, control of chronic illnesses, and missed opportunities for preventive care. Family history documentation collected by the providers was limited and 44.4% had no family history. There was no routine depression screening process, although 48.9% of the clients had red flags (warning signals) for depression. Laboratory values used for screening control of chronic disease in the medical records were: fasting glucose levels ⩽100 mg/dL (46%), total cholesterol levels ⩽200 mg/dL (38%), and blood pressure ⩽120/80 mmHg (23%). The results highlight the need to focus on depression screening as part of preventive care and the management of chronic disease in the primary care setting. Copyright 2013, SLACK Incorporated.

BPSK Demodulation Using Digital Signal Processing

NASA Technical Reports Server (NTRS)

Garcia, Thomas R.

1996-01-01

A digital communications signal is a sinusoidal waveform that is modified by a binary (digital) information signal. The sinusoidal waveform is called the carrier. The carrier may be modified in amplitude, frequency, phase, or a combination of these. In this project a binary phase shift keyed (BPSK) signal is the communication signal. In a BPSK signal the phase of the carrier is set to one of two states, 180 degrees apart, by a binary (i.e., 1 or 0) information signal. A digital signal is a sampled version of a "real world" time continuous signal. The digital signal is generated by sampling the continuous signal at discrete points in time. The rate at which the signal is sampled is called the sampling rate (f(s)). The device that performs this operation is called an analog-to-digital (A/D) converter or a digitizer. The digital signal is composed of the sequence of individual values of the sampled BPSK signal. Digital signal processing (DSP) is the modification of the digital signal by mathematical operations. A device that performs this processing is called a digital signal processor. After processing, the digital signal may then be converted back to an analog signal using a digital-to-analog (D/A) converter. The goal of this project is to develop a system that will recover the digital information from a BPSK signal using DSP techniques. The project is broken down into the following steps: (1) Development of the algorithms required to demodulate the BPSK signal; (2) Simulation of the system; and (3) Implementation a BPSK receiver using digital signal processing hardware.

Communication among Oral Bacteria

PubMed Central

Kolenbrander, Paul E.; Andersen, Roxanna N.; Blehert, David S.; Egland, Paul G.; Foster, Jamie S.; Palmer, Robert J.

2002-01-01

Human oral bacteria interact with their environment by attaching to surfaces and establishing mixed-species communities. As each bacterial cell attaches, it forms a new surface to which other cells can adhere. Adherence and community development are spatiotemporal; such order requires communication. The discovery of soluble signals, such as autoinducer-2, that may be exchanged within multispecies communities to convey information between organisms has emerged as a new research direction. Direct-contact signals, such as adhesins and receptors, that elicit changes in gene expression after cell-cell contact and biofilm growth are also an active research area. Considering that the majority of oral bacteria are organized in dense three-dimensional biofilms on teeth, confocal microscopy and fluorescently labeled probes provide valuable approaches for investigating the architecture of these organized communities in situ. Oral biofilms are readily accessible to microbiologists and are excellent model systems for studies of microbial communication. One attractive model system is a saliva-coated flowcell with oral bacterial biofilms growing on saliva as the sole nutrient source; an intergeneric mutualism is discussed. Several oral bacterial species are amenable to genetic manipulation for molecular characterization of communication both among bacteria and between bacteria and the host. A successful search for genes critical for mixed-species community organization will be accomplished only when it is conducted with mixed-species communities. PMID:12209001

Gas turbine engine control system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Idelchik, M.S.

1991-02-19

This paper describes a method for controlling a gas turbine engine. It includes receiving an error signal and processing the error signal to form a primary control signal; receiving at least one anticipatory demand signal and processing the signal to form an anticipatory fuel control signal.

Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

PubMed Central

Martinez, Alexander S.; Faist, Akasha M.

2016-01-01

Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species) and belowground (species active in organic and mineral soil layers) arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community) and modified Winkler funnels (belowground community) and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity) among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the aboveground arthropod communities and vegetation and soil properties, but no significant association among belowground arthropod communities and environmental factors. Discussion Our results suggest context-dependent influences of stochastic and deterministic community assembly processes across different fractions of a spatially co-occurring ground-dwelling arthropod community following disturbance. This variation in assembly may be linked to contrasting ecological strategies and dispersal rates within above- and below-ground communities. Our findings add to a growing body of evidence indicating concurrent influences of stochastic and deterministic processes in community assembly, and highlight the need to consider potential variation across different fractions of biotic communities when testing community ecology theory and considering conservation strategies. PMID:27761333

Changes in assembly processes in soil bacterial communities following a wildfire disturbance.

PubMed

Ferrenberg, Scott; O'Neill, Sean P; Knelman, Joseph E; Todd, Bryan; Duggan, Sam; Bradley, Daniel; Robinson, Taylor; Schmidt, Steven K; Townsend, Alan R; Williams, Mark W; Cleveland, Cory C; Melbourne, Brett A; Jiang, Lin; Nemergut, Diana R

2013-06-01

Although recent work has shown that both deterministic and stochastic processes are important in structuring microbial communities, the factors that affect the relative contributions of niche and neutral processes are poorly understood. The macrobiological literature indicates that ecological disturbances can influence assembly processes. Thus, we sampled bacterial communities at 4 and 16 weeks following a wildfire and used null deviation analysis to examine the role that time since disturbance has in community assembly. Fire dramatically altered bacterial community structure and diversity as well as soil chemistry for both time-points. Community structure shifted between 4 and 16 weeks for both burned and unburned communities. Community assembly in burned sites 4 weeks after fire was significantly more stochastic than in unburned sites. After 16 weeks, however, burned communities were significantly less stochastic than unburned communities. Thus, we propose a three-phase model featuring shifts in the relative importance of niche and neutral processes as a function of time since disturbance. Because neutral processes are characterized by a decoupling between environmental parameters and community structure, we hypothesize that a better understanding of community assembly may be important in determining where and when detailed studies of community composition are valuable for predicting ecosystem function.

Changes in assembly processes in soil bacterial communities following a wildfire disturbance

PubMed Central

Ferrenberg, Scott; O'Neill, Sean P; Knelman, Joseph E; Todd, Bryan; Duggan, Sam; Bradley, Daniel; Robinson, Taylor; Schmidt, Steven K; Townsend, Alan R; Williams, Mark W; Cleveland, Cory C; Melbourne, Brett A; Jiang, Lin; Nemergut, Diana R

2013-01-01

Although recent work has shown that both deterministic and stochastic processes are important in structuring microbial communities, the factors that affect the relative contributions of niche and neutral processes are poorly understood. The macrobiological literature indicates that ecological disturbances can influence assembly processes. Thus, we sampled bacterial communities at 4 and 16 weeks following a wildfire and used null deviation analysis to examine the role that time since disturbance has in community assembly. Fire dramatically altered bacterial community structure and diversity as well as soil chemistry for both time-points. Community structure shifted between 4 and 16 weeks for both burned and unburned communities. Community assembly in burned sites 4 weeks after fire was significantly more stochastic than in unburned sites. After 16 weeks, however, burned communities were significantly less stochastic than unburned communities. Thus, we propose a three-phase model featuring shifts in the relative importance of niche and neutral processes as a function of time since disturbance. Because neutral processes are characterized by a decoupling between environmental parameters and community structure, we hypothesize that a better understanding of community assembly may be important in determining where and when detailed studies of community composition are valuable for predicting ecosystem function. PMID:23407312

Development of a Model, Metal-reducing Microbial Community for a System Biology Level Assessment of Desulfovibrio vulgaris as part of a Community

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elias, Dwayne; Schadt, Christopher; Miller, Lance

2010-05-17

One of the largest experimental gaps is between the simplicity of pure cultures and the complexity of open environmental systems, particularly in metal-contaminated areas. These microbial communities form ecosystem foundations, drive biogeochemical processes, and are relevant for biotechnology and bioremediation. A model, metal-reducing microbial community was constructed as either syntrophic or competitive to study microbial cell to cell interactions, cell signaling and competition for resources. The microbial community was comprised of the metal-reducing Desulfovibrio vulgaris Hildenborough and Geobacter sulfurreducens PCA. Additionally, Methanococcus maripaludis S2 was added to study complete carbon reduction and maintain a low hydrogen partial pressure for syntrophismmore » to occur. Further, considerable work has been published on D. vulgaris and the D. vulgaris/ Mc. maripaludis co-culture both with and without stress. We are extending this work by conducting the same stress conditions on the model community. Additionally, this comprehensive investigation includes physiological and metabolic analyses as well as specially designed mRNA microarrays with the genes for all three organisms on one slide so as to follow gene expression changes in the various cultivation conditions as well as being comparable to the co- and individual cultures. Further, state-of -the-art comprehensive AMT tag proteomics allows for these comparisons at the protein level for a systems biology assessment of a model, metal-reducing microbial community. Preliminary data revealed that lactate oxidation by D. vulgaris was sufficient to support both G. sulfurreducens and M. maripaludis via the excretion of H2 and acetate. Fumarate was utilized by G. sulfurreducens and reduced to succinate since neither of the other two organisms can reduce fumarate. Methane was quantified, suggesting acetate and H2 concentrations were sufficient for M. maripaludis. Steady state community cultivation will allow for a comprehensive, system biology level analysis of a metal-reducing microbial community.« less

A community engagement process for families with children with disabilities: lessons in leadership and policy.

PubMed

Vargas, Claudia María; Arauza, Consuelo; Folsom, Kim; Luna, María del Rosario; Gutiérrez, Lucy; Frerking, Patricia Ohliger; Shelton, Kathleen; Foreman, Carl; Waffle, David; Reynolds, Richard; Cooper, Phillip J

2012-01-01

This article examines a community engagement process developed as part of leadership training for clinical trainees in the Oregon Leadership Education for Neurodevelopmental and Related Disabilities (LEND) Program in a complex community with diverse families who have children with disabilities. The goal is to examine the process and lessons learned for clinical trainees and their mentors from such a process. This is a case study conducted as community-engaged action research by participant-observers involved in the Cornelius community for the past 4 years. The authors include faculty members and clinical trainees of the Oregon LEND Program at the Oregon Health & Science University, families with children with disabilities in the community, and city officials. It is a critical case study in that it studied a community engagement process in one of the poorest communities in the region, with an unusually high population of children with disabilities, and in a community that is over half Latino residents. Lessons learned here can be helpful in a variety of settings. Community engagement forum, community engagement processes, a debriefing using a seven-element feasibility framework, and trainee evaluations are key elements. A community engagement forum is a meeting to which community members and stakeholders from pertinent agencies are invited. Community engagement processes used include a steering committee made up of, and guided by community members which meets on a regular basis to prioritize and carry out responses to problems. Trainee evaluations are based on a set of questions to trigger open-ended responses. Lessons learned are based on assessments of initial and long-term outcomes of the community engagement processes in which families, community members, local officials and LEND trainees and faculty participate as well as by trainee participant-observations, end of year evaluations and trainee debriefings at the time of the initial community assessment forum. The thesis that emerges is that community engagement processes can afford significant opportunities for clinicians in training to develop their leadership skills toward improving maternal and child health for minority families with children with disabilities while building capacity in families for advocacy and facilitating change in the community.

An Analog Circuit Approximation of the Discrete Wavelet Transform for Ultra Low Power Signal Processing in Wearable Sensor Nodes

PubMed Central

Casson, Alexander J.

2015-01-01

Ultra low power signal processing is an essential part of all sensor nodes, and particularly so in emerging wearable sensors for biomedical applications. Analog signal processing has an important role in these low power, low voltage, low frequency applications, and there is a key drive to decrease the power consumption of existing analog domain signal processing and to map more signal processing approaches into the analog domain. This paper presents an analog domain signal processing circuit which approximates the output of the Discrete Wavelet Transform (DWT) for use in ultra low power wearable sensors. Analog filters are used for the DWT filters and it is demonstrated how these generate analog domain DWT-like information that embeds information from Butterworth and Daubechies maximally flat mother wavelet responses. The Analog DWT is realised in hardware via gmC circuits, designed to operate from a 1.3 V coin cell battery, and provide DWT-like signal processing using under 115 nW of power when implemented in a 0.18 μm CMOS process. Practical examples demonstrate the effective use of the new Analog DWT on ECG (electrocardiogram) and EEG (electroencephalogram) signals recorded from humans. PMID:26694414

An Analog Circuit Approximation of the Discrete Wavelet Transform for Ultra Low Power Signal Processing in Wearable Sensor Nodes.

PubMed

Casson, Alexander J

2015-12-17

Ultra low power signal processing is an essential part of all sensor nodes, and particularly so in emerging wearable sensors for biomedical applications. Analog signal processing has an important role in these low power, low voltage, low frequency applications, and there is a key drive to decrease the power consumption of existing analog domain signal processing and to map more signal processing approaches into the analog domain. This paper presents an analog domain signal processing circuit which approximates the output of the Discrete Wavelet Transform (DWT) for use in ultra low power wearable sensors. Analog filters are used for the DWT filters and it is demonstrated how these generate analog domain DWT-like information that embeds information from Butterworth and Daubechies maximally flat mother wavelet responses. The Analog DWT is realised in hardware via g(m)C circuits, designed to operate from a 1.3 V coin cell battery, and provide DWT-like signal processing using under 115 nW of power when implemented in a 0.18 μm CMOS process. Practical examples demonstrate the effective use of the new Analog DWT on ECG (electrocardiogram) and EEG (electroencephalogram) signals recorded from humans.

Investigation of optical current transformer signal processing method based on an improved Kalman algorithm

NASA Astrophysics Data System (ADS)

Shen, Yan; Ge, Jin-ming; Zhang, Guo-qing; Yu, Wen-bin; Liu, Rui-tong; Fan, Wei; Yang, Ying-xuan

2018-01-01

This paper explores the problem of signal processing in optical current transformers (OCTs). Based on the noise characteristics of OCTs, such as overlapping signals, noise frequency bands, low signal-to-noise ratios, and difficulties in acquiring statistical features of noise power, an improved standard Kalman filtering algorithm was proposed for direct current (DC) signal processing. The state-space model of the OCT DC measurement system is first established, and then mixed noise can be processed by adding mixed noise into measurement and state parameters. According to the minimum mean squared error criterion, state predictions and update equations of the improved Kalman algorithm could be deduced based on the established model. An improved central difference Kalman filter was proposed for alternating current (AC) signal processing, which improved the sampling strategy and noise processing of colored noise. Real-time estimation and correction of noise were achieved by designing AC and DC noise recursive filters. Experimental results show that the improved signal processing algorithms had a good filtering effect on the AC and DC signals with mixed noise of OCT. Furthermore, the proposed algorithm was able to achieve real-time correction of noise during the OCT filtering process.

Neutral Community Dynamics and the Evolution of Species Interactions.

PubMed

Coelho, Marco Túlio P; Rangel, Thiago F

2018-04-01

A contemporary goal in ecology is to determine the ecological and evolutionary processes that generate recurring structural patterns in mutualistic networks. One of the great challenges is testing the capacity of neutral processes to replicate observed patterns in ecological networks, since the original formulation of the neutral theory lacks trophic interactions. Here, we develop a stochastic-simulation neutral model adding trophic interactions to the neutral theory of biodiversity. Without invoking ecological differences among individuals of different species, and assuming that ecological interactions emerge randomly, we demonstrate that a spatially explicit multitrophic neutral model is able to capture the recurrent structural patterns of mutualistic networks (i.e., degree distribution, connectance, nestedness, and phylogenetic signal of species interactions). Nonrandom species distribution, caused by probabilistic events of migration and speciation, create nonrandom network patterns. These findings have broad implications for the interpretation of niche-based processes as drivers of ecological networks, as well as for the integration of network structures with demographic stochasticity.

Serpentinite Mud Volcanism: Observations, Processes, and Implications

NASA Astrophysics Data System (ADS)

Fryer, Patricia

2012-01-01

Large serpentinite mud volcanoes form on the overriding plate of the Mariana subduction zone. Fluids from the descending plate hydrate (serpentinize) the forearc mantle and enable serpentinite muds to rise along faults to the seafloor. The seamounts are direct windows into subduction processes at depths far too deep to be accessed by any known technology. Fluid compositions vary with distance from the trench, signaling changes in chemical reactions as temperature and pressure increase. The parageneses of rocks in the mudflows permits us to constrain the physical conditions of the decollement region. If eruptive episodes are related to seismicity, seafloor observatories at these seamounts hold the potential to capture a subduction event and trace the effects of eruption on the biological communities that the slab fluids support, such as extremophile Archaea. The microorganisms that inhabit this high-pH, extreme environment support their growth by utilizing chemical constituents present in the slab fluids. Some researchers now contend that the serpentinization process itself may hold the key to the origin of life on Earth.

Serpentinite mud volcanism: observations, processes, and implications.

PubMed

Fryer, Patricia

2012-01-01

Large serpentinite mud volcanoes form on the overriding plate of the Mariana subduction zone. Fluids from the descending plate hydrate (serpentinize) the forearc mantle and enable serpentinite muds to rise along faults to the seafloor. The seamounts are direct windows into subduction processes at depths far too deep to be accessed by any known technology. Fluid compositions vary with distance from the trench, signaling changes in chemical reactions as temperature and pressure increase. The parageneses of rocks in the mudflows permits us to constrain the physical conditions of the decollement region. If eruptive episodes are related to seismicity, seafloor observatories at these seamounts hold the potential to capture a subduction event and trace the effects of eruption on the biological communities that the slab fluids support, such as extremophile Archaea. The microorganisms that inhabit this high-pH, extreme environment support their growth by utilizing chemical constituents present in the slab fluids. Some researchers now contend that the serpentinization process itself may hold the key to the origin of life on Earth.

K-mean clustering algorithm for processing signals from compound semiconductor detectors

NASA Astrophysics Data System (ADS)

Tada, Tsutomu; Hitomi, Keitaro; Wu, Yan; Kim, Seong-Yun; Yamazaki, Hiromichi; Ishii, Keizo

2011-12-01

The K-mean clustering algorithm was employed for processing signal waveforms from TlBr detectors. The signal waveforms were classified based on its shape reflecting the charge collection process in the detector. The classified signal waveforms were processed individually to suppress the pulse height variation of signals due to the charge collection loss. The obtained energy resolution of a 137Cs spectrum measured with a 0.5 mm thick TlBr detector was 1.3% FWHM by employing 500 clusters.

Signal processing in ultrasound. [for diagnostic medicine

NASA Technical Reports Server (NTRS)

Le Croissette, D. H.; Gammell, P. M.

1978-01-01

Signal is the term used to denote the characteristic in the time or frequency domain of the probing energy of the system. Processing of this signal in diagnostic ultrasound occurs as the signal travels through the ultrasonic and electrical sections of the apparatus. The paper discusses current signal processing methods, postreception processing, display devices, real-time imaging, and quantitative measurements in noninvasive cardiology. The possibility of using deconvolution in a single transducer system is examined, and some future developments using digital techniques are outlined.

Monolithic circuits for barium fluoride detectors used in nuclear physics experiments. CRADA final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varner, R.L.; Blankenship, J.L.; Beene, J.R.

1998-02-01

Custom monolithic electronic circuits have been developed recently for large detector applications in high energy physics where subsystems require tens of thousands of channels of signal processing and data acquisition. In the design and construction of these enormous detectors, it has been found that monolithic circuits offer significant advantages over discrete implementations through increased performance, flexible packaging, lower power and reduced cost per channel. Much of the integrated circuit design for the high energy physics community is directly applicable to intermediate energy heavy-ion and electron physics. This STTR project conducted in collaboration with researchers at the Holifield Radioactive Ion Beammore » Facility (HRIBF) at Oak Ridge National Laboratory, sought to develop a new integrated circuit chip set for barium fluoride (BaF{sub 2}) detector arrays based upon existing CMOS monolithic circuit designs created for the high energy physics experiments. The work under the STTR Phase 1 demonstrated through the design, simulation, and testing of several prototype chips the feasibility of using custom CMOS integrated circuits for processing signals from BaF{sub 2} detectors. Function blocks including charge-sensitive amplifiers, comparators, one shots, time-to-amplitude converters, analog memory circuits and buffer amplifiers were implemented during Phase 1 effort. Experimental results from bench testing and laboratory testing with sources were documented.« less

A scale-up field experiment for the monitoring of a burning process using chemical, audio, and video sensors.

PubMed

Stavrakakis, P; Agapiou, A; Mikedi, K; Karma, S; Statheropoulos, M; Pallis, G C; Pappa, A

2014-01-01

Fires are becoming more violent and frequent resulting in major economic losses and long-lasting effects on communities and ecosystems; thus, efficient fire monitoring is becoming a necessity. A novel triple multi-sensor approach was developed for monitoring and studying the burning of dry forest fuel in an open field scheduled experiment; chemical, optical, and acoustical sensors were combined to record the fire spread. The results of this integrated field campaign for real-time monitoring of the fire event are presented and discussed. Chemical analysis, despite its limitations, corresponded to the burning process with a minor time delay. Nevertheless, the evolution profile of CO2, CO, NO, and O2 were detected and monitored. The chemical monitoring of smoke components enabled the observing of the different fire phases (flaming, smoldering) based on the emissions identified in each phase. The analysis of fire acoustical signals presented accurate and timely response to the fire event. In the same content, the use of a thermographic camera, for monitoring the biomass burning, was also considerable (both profiles of the intensities of average gray and red component greater than 230) and presented similar promising potentials to audio results. Further work is needed towards integrating sensors signals for automation purposes leading to potential applications in real situations.

Nuclear Receptor Signaling Atlas: Opening Access to the Biology of Nuclear Receptor Signaling Pathways

PubMed Central

Becnel, Lauren B.; Darlington, Yolanda F.; Ochsner, Scott A.; Easton-Marks, Jeremy R.; Watkins, Christopher M.; McOwiti, Apollo; Kankanamge, Wasula H.; Wise, Michael W.; DeHart, Michael; Margolis, Ronald N.; McKenna, Neil J.

2015-01-01

Signaling pathways involving nuclear receptors (NRs), their ligands and coregulators, regulate tissue-specific transcriptomes in diverse processes, including development, metabolism, reproduction, the immune response and neuronal function, as well as in their associated pathologies. The Nuclear Receptor Signaling Atlas (NURSA) is a Consortium focused around a Hub website (www.nursa.org) that annotates and integrates diverse ‘omics datasets originating from the published literature and NURSA-funded Data Source Projects (NDSPs). These datasets are then exposed to the scientific community on an Open Access basis through user-friendly data browsing and search interfaces. Here, we describe the redesign of the Hub, version 3.0, to deploy “Web 2.0” technologies and add richer, more diverse content. The Molecule Pages, which aggregate information relevant to NR signaling pathways from myriad external databases, have been enhanced to include resources for basic scientists, such as post-translational modification sites and targeting miRNAs, and for clinicians, such as clinical trials. A portal to NURSA’s Open Access, PubMed-indexed journal Nuclear Receptor Signaling has been added to facilitate manuscript submissions. Datasets and information on reagents generated by NDSPs are available, as is information concerning periodic new NDSP funding solicitations. Finally, the new website integrates the Transcriptomine analysis tool, which allows for mining of millions of richly annotated public transcriptomic data points in the field, providing an environment for dataset re-use and citation, bench data validation and hypothesis generation. We anticipate that this new release of the NURSA database will have tangible, long term benefits for both basic and clinical research in this field. PMID:26325041

Signal quality and Bayesian signal processing in neurofeedback based on real-time fMRI.

PubMed

Koush, Yury; Zvyagintsev, Mikhail; Dyck, Miriam; Mathiak, Krystyna A; Mathiak, Klaus

2012-01-02

Real-time fMRI allows analysis and visualization of the brain activity online, i.e. within one repetition time. It can be used in neurofeedback applications where subjects attempt to control an activation level in a specified region of interest (ROI) of their brain. The signal derived from the ROI is contaminated with noise and artifacts, namely with physiological noise from breathing and heart beat, scanner drift, motion-related artifacts and measurement noise. We developed a Bayesian approach to reduce noise and to remove artifacts in real-time using a modified Kalman filter. The system performs several signal processing operations: subtraction of constant and low-frequency signal components, spike removal and signal smoothing. Quantitative feedback signal quality analysis was used to estimate the quality of the neurofeedback time series and performance of the applied signal processing on different ROIs. The signal-to-noise ratio (SNR) across the entire time series and the group event-related SNR (eSNR) were significantly higher for the processed time series in comparison to the raw data. Applied signal processing improved the t-statistic increasing the significance of blood oxygen level-dependent (BOLD) signal changes. Accordingly, the contrast-to-noise ratio (CNR) of the feedback time series was improved as well. In addition, the data revealed increase of localized self-control across feedback sessions. The new signal processing approach provided reliable neurofeedback, performed precise artifacts removal, reduced noise, and required minimal manual adjustments of parameters. Advanced and fast online signal processing algorithms considerably increased the quality as well as the information content of the control signal which in turn resulted in higher contingency in the neurofeedback loop. Copyright © 2011 Elsevier Inc. All rights reserved.

Journal Impact Factor Shapes Scientists’ Reward Signal in the Prospect of Publication

PubMed Central

Paulus, Frieder Michel; Rademacher, Lena; Schäfer, Theo Alexander Jose; Müller-Pinzler, Laura; Krach, Sören

2015-01-01

The incentive structure of a scientist’s life is increasingly mimicking economic principles. While intensely criticized, the journal impact factor (JIF) has taken a role as the new currency for scientists. Successful goal-directed behavior in academia thus requires knowledge about the JIF. Using functional neuroimaging we examined how the JIF, as a powerful incentive in academia, has shaped the behavior of scientists and the reward signal in the striatum. We demonstrate that the reward signal in the nucleus accumbens increases with higher JIF during the anticipation of a publication and found a positive correlation with the personal publication record (pJIF) supporting the notion that scientists have incorporated the predominant reward principle of the scientific community in their reward system. The implications of this behavioral adaptation within the ecological niche of the scientist’s habitat remain unknown, but may also have effects which were not intended by the community. PMID:26555725

DSPACE hardware architecture for on-board real-time image/video processing in European space missions

NASA Astrophysics Data System (ADS)

Saponara, Sergio; Donati, Massimiliano; Fanucci, Luca; Odendahl, Maximilian; Leupers, Reiner; Errico, Walter

2013-02-01

The on-board data processing is a vital task for any satellite and spacecraft due to the importance of elaborate the sensing data before sending them to the Earth, in order to exploit effectively the bandwidth to the ground station. In the last years the amount of sensing data collected by scientific and commercial space missions has increased significantly, while the available downlink bandwidth is comparatively stable. The increasing demand of on-board real-time processing capabilities represents one of the critical issues in forthcoming European missions. Faster and faster signal and image processing algorithms are required to accomplish planetary observation, surveillance, Synthetic Aperture Radar imaging and telecommunications. The only available space-qualified Digital Signal Processor (DSP) free of International Traffic in Arms Regulations (ITAR) restrictions faces inadequate performance, thus the development of a next generation European DSP is well known to the space community. The DSPACE space-qualified DSP architecture fills the gap between the computational requirements and the available devices. It leverages a pipelined and massively parallel core based on the Very Long Instruction Word (VLIW) paradigm, with 64 registers and 8 operational units, along with cache memories, memory controllers and SpaceWire interfaces. Both the synthesizable VHDL and the software development tools are generated from the LISA high-level model. A Xilinx-XC7K325T FPGA is chosen to realize a compact PCI demonstrator board. Finally first synthesis results on CMOS standard cell technology (ASIC 180 nm) show an area of around 380 kgates and a peak performance of 1000 MIPS and 750 MFLOPS at 125MHz.

Marine Chemical Ecology: Chemical Signals and Cues Structure Marine Populations, Communities, and Ecosystems

PubMed Central

Hay, Mark E.

2012-01-01

Chemical cues constitute much of the language of life in the sea. Our understanding of biotic interactions and their effects on marine ecosystems will advance more rapidly if this language is studied and understood. Here, I review how chemical cues regulate critical aspects of the behavior of marine organisms from bacteria to phytoplankton to benthic invertebrates and water column fishes. These chemically mediated interactions strongly affect population structure, community organization, and ecosystem function. Chemical cues determine foraging strategies, feeding choices, commensal associations, selection of mates and habitats, competitive interactions, and transfer of energy and nutrients within and among ecosystems. In numerous cases, the indirect effects of chemical signals on behavior have as much or more effect on community structure and function as the direct effects of consumers and pathogens. Chemical cues are critical for understanding marine systems, but their omnipresence and impact are inadequately recognized. PMID:21141035

Directional dual-tree rational-dilation complex wavelet transform.

PubMed

Serbes, Gorkem; Gulcur, Halil Ozcan; Aydin, Nizamettin

2014-01-01

Dyadic discrete wavelet transform (DWT) has been used successfully in processing signals having non-oscillatory transient behaviour. However, due to the low Q-factor property of their wavelet atoms, the dyadic DWT is less effective in processing oscillatory signals such as embolic signals (ESs). ESs are extracted from quadrature Doppler signals, which are the output of Doppler ultrasound systems. In order to process ESs, firstly, a pre-processing operation known as phase filtering for obtaining directional signals from quadrature Doppler signals must be employed. Only then, wavelet based methods can be applied to these directional signals for further analysis. In this study, a directional dual-tree rational-dilation complex wavelet transform, which can be applied directly to quadrature signals and has the ability of extracting directional information during analysis, is introduced.

FijiWingsPolarity: An open source toolkit for semi-automated detection of cell polarity.

PubMed

Dobens, Leonard L; Shipman, Anna; Axelrod, Jeffrey D

2018-01-02

Epithelial cells are defined by apical-basal and planar cell polarity (PCP) signaling, the latter of which establishes an orthogonal plane of polarity in the epithelial sheet. PCP signaling is required for normal cell migration, differentiation, stem cell generation and tissue repair, and defects in PCP have been associated with developmental abnormalities, neuropathologies and cancers. While the molecular mechanism of PCP is incompletely understood, the deepest insights have come from Drosophila, where PCP is manifest in hairs and bristles across the adult cuticle and organization of the ommatidia in the eye. Fly wing cells are marked by actin-rich trichome structures produced at the distal edge of each cell in the developing wing epithelium and in a mature wing the trichomes orient collectively in the distal direction. Genetic screens have identified key PCP signaling pathway components that disrupt trichome orientation, which has been measured manually in a tedious and error prone process. Here we describe a set of image processing and pattern-recognition macros that can quantify trichome arrangements in micrographs and mark these directly by color, arrow or colored arrow to indicate trichome location, length and orientation. Nearest neighbor calculations are made to exploit local differences in orientation to better and more reliably detect and highlight local defects in trichome polarity. We demonstrate the use of these tools on trichomes in adult wing preps and on actin-rich developing trichomes in pupal wing epithelia stained with phalloidin. FijiWingsPolarity is freely available and will be of interest to a broad community of fly geneticists studying the effect of gene function on PCP.

Detecting Below-Ground Processes, Diversity, and Ecosystem Function in a Savanna Ecosystem Using Spectroscopy Across Different Vegetation Layers

NASA Astrophysics Data System (ADS)

Cavender-Bares, J.; Schweiger, A. K.; Madritch, M. D.; Gamon, J. A.; Hobbie, S. E.; Montgomery, R.; Townsend, P. A.

2017-12-01

Above-and below-ground plant traits are important for substrate input to the rhizosphere. The substrate composition of the rhizosphere, in turn, affects the diversity of soil organisms, influences soil biochemistry, and water content, and resource availability for plant growth. This has substantial consequences for ecosystem functions, such as above-ground productivity and stability. Above-ground plant chemical and structural traits can be linked to the characteristics of other plant organs, including roots. Airborne imaging spectroscopy has been successfully used to model and predict chemical and structural traits of the above-ground vegetation. However, remotely sensed images capture, almost exclusively, signals from the top of the canopy, providing limited direct information about understory vegetation. Here, we use a data set collected in a savanna ecosystem consisting of spectral measurements gathered at the leaf, the whole plant, and vegetation canopy level to test for hypothesized linkages between above- and below-ground processes that influence root biomass, soil biochemistry, and the diversity of the soil community. In this environment, consisting of herbaceous vegetation intermixed with shrubs and trees growing at variable densities, we investigate the contribution of different vegetation strata to soil characteristics and test the ability of imaging spectroscopy to detect these in plant communities with contrasting vertical structure.

The Next-Generation Very Large Array: Technical Overview

NASA Astrophysics Data System (ADS)

McKinnon, Mark; Selina, Rob

2018-01-01

As part of its mandate as a national observatory, the NRAO is looking toward the long range future of radio astronomy and fostering the long term growth of the US astronomical community. NRAO has sponsored a series of science and technical community meetings to consider the science mission and design of a next-generation Very Large Array (ngVLA), building on the legacies of the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Array (VLA).The basic ngVLA design emerging from these discussions is an interferometric array with approximately ten times the sensitivity and ten times higher spatial resolution than the VLA and ALMA radio telescopes, optimized for operation in the wavelength range 0.3cm to 3cm. The ngVLA would open a new window on the Universe through ultra-sensitive imaging of thermal line and continuum emission down to milli-arcsecond resolution, as well as unprecedented broadband continuum polarimetric imaging of non-thermal processes. The specifications and concepts for major ngVLA system elements are rapidly converging.We will provide an overview of the current system design of the ngVLA. The concepts for major system elements such as the antenna, receiving electronics, and central signal processing will be presented. We will also describe the major development activities that are presently underway to advance the design.

75 FR 56868 - Implementation of the Satellite Television Extension and Localism Act of 2010

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-17

.... (``Subsection (c) resolves the phantom signal ambiguity that required cable systems to pay royalty fees for... distant signals to some but not all communities to calculate royalty fees on the basis of the actual...'s computation of its royalty fee consistent with the methodology described in subparagraph (C)(iii...

Highly Sensitive Biosensing with Solid-State Nanopores Displaying Enzymatically Reconfigurable Rectification Properties.

PubMed

Pérez-Mitta, Gonzalo; Peinetti, Ana S; Cortez, M Lorena; Toimil-Molares, María Eugenia; Trautmann, Christina; Azzaroni, Omar

2018-05-09

Molecular design of biosensors based on enzymatic processes taking place in nanofluidic elements is receiving increasing attention by the scientific community. In this work, we describe the construction of novel ultrasensitive enzymatic nanopore biosensors employing "reactive signal amplifiers" as key elements coupled to the transduction mechanism. The proposed framework offers innovative design concepts not only to amplify the detected ionic signal and develop ultrasensitive nanopore-based sensors but also to construct nanofluidic diodes displaying specific chemo-reversible rectification properties. The integrated approach is demonstrated by electrostatically assembling poly(allylamine) on the anionic pore walls followed by the assembly of urease. We show that the cationic weak polyelectrolyte acts as a "reactive signal amplifier" in the presence of local pH changes induced by the enzymatic reaction. These bioinduced variations in proton concentration ultimately alter the protonation degree of the polyamine resulting in amplifiable, controlled, and reproducible changes in the surface charge of the pore walls, and consequently on the generated ionic signals. The "iontronic" response of the as-obtained devices is fully reversible, and nanopores are reused and assayed with different urea concentrations, thus ensuring reliable design. The limit of detection (LOD) was 1 nM. To the best of our knowledge, this value is the lowest LOD reported to date for enzymatic urea detection. In this context, we envision that this approach based on the use of "reactive signal amplifiers" into solid-state nanochannels will provide new alternatives for the molecular design of highly sensitive nanopore biosensors as well as (bio)chemically addressable nanofluidic elements.

Metabolic Network Modeling of Microbial Communities

PubMed Central

Biggs, Matthew B.; Medlock, Gregory L.; Kolling, Glynis L.

2015-01-01

Genome-scale metabolic network reconstructions and constraint-based analysis are powerful methods that have the potential to make functional predictions about microbial communities. Current use of genome-scale metabolic networks to characterize the metabolic functions of microbial communities includes species compartmentalization, separating species-level and community-level objectives, dynamic analysis, the “enzyme-soup” approach, multi-scale modeling, and others. There are many challenges inherent to the field, including a need for tools that accurately assign high-level omics signals to individual community members, new automated reconstruction methods that rival manual curation, and novel algorithms for integrating omics data and engineering communities. As technologies and modeling frameworks improve, we expect that there will be proportional advances in the fields of ecology, health science, and microbial community engineering. PMID:26109480

Engineering quorum sensing signaling of Pseudomonas for enhanced wastewater treatment and electricity harvest: A review.

PubMed

Yong, Yang-Chun; Wu, Xiang-Yang; Sun, Jian-Zhong; Cao, Ying-Xiu; Song, Hao

2015-12-01

Cell-cell communication that enables synchronized population behaviors in microbial communities dictates various biological processes. It is of great interest to unveil the underlying mechanisms of fine-tuning cell-cell communication to achieve environmental and energy applications. Pseudomonas is a ubiquitous microbe in environments that had wide applications in bioremediation and bioenergy generation. The quorum sensing (QS, a generic cell-cell communication mechanism) systems of Pseudomonas underlie the aromatics biodegradation, denitrification and electricity harvest. Here, we reviewed the recent progresses of the genetic strategies in engineering QS circuits to improve efficiency of wastewater treatment and the performance of microbial fuel cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

Phylogenetic Paleoecology: Tree-Thinking and Ecology in Deep Time.

PubMed

Lamsdell, James C; Congreve, Curtis R; Hopkins, Melanie J; Krug, Andrew Z; Patzkowsky, Mark E

2017-06-01

The new and emerging field of phylogenetic paleoecology leverages the evolutionary relationships among species to explain temporal and spatial changes in species diversity, abundance, and distribution in deep time. This field is poised for rapid progress as knowledge of the evolutionary relationships among fossil species continues to expand. In particular, this approach will lend new insights to many of the longstanding questions in evolutionary biology, such as: the relationships among character change, ecology, and evolutionary rates; the processes that determine the evolutionary relationships among species within communities and along environmental gradients; and the phylogenetic signal underlying ecological selectivity in background and mass extinctions and in major evolutionary radiations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Software platform for rapid prototyping of NIRS brain computer interfacing techniques.

PubMed

Matthews, Fiachra; Soraghan, Christopher; Ward, Tomas E; Markham, Charles; Pearlmutter, Barak A

2008-01-01

This paper describes the control system of a next-generation optical brain-computer interface (BCI). Using functional near-infrared spectroscopy (fNIRS) as a BCI modality is a relatively new concept, and research has only begun to explore approaches for its implementation. It is necessary to have a system by which it is possible to investigate the signal processing and classification techniques available in the BCI community. Most importantly, these techniques must be easily testable in real-time applications. The system we describe was built using LABVIEW, a graphical programming language designed for interaction with National Instruments hardware. This platform allows complete configurability from hardware control and regulation, testing and filtering in a graphical interface environment.

Designing Guiding Systems for Brain-Computer Interfaces

PubMed Central

Kosmyna, Nataliya; Lécuyer, Anatole

2017-01-01

Brain–Computer Interface (BCI) community has focused the majority of its research efforts on signal processing and machine learning, mostly neglecting the human in the loop. Guiding users on how to use a BCI is crucial in order to teach them to produce stable brain patterns. In this work, we explore the instructions and feedback for BCIs in order to provide a systematic taxonomy to describe the BCI guiding systems. The purpose of our work is to give necessary clues to the researchers and designers in Human–Computer Interaction (HCI) in making the fusion between BCIs and HCI more fruitful but also to better understand the possibilities BCIs can provide to them. PMID:28824400

Towards the understanding of network information processing in biology

NASA Astrophysics Data System (ADS)

Singh, Vijay

Living organisms perform incredibly well in detecting a signal present in the environment. This information processing is achieved near optimally and quite reliably, even though the sources of signals are highly variable and complex. The work in the last few decades has given us a fair understanding of how individual signal processing units like neurons and cell receptors process signals, but the principles of collective information processing on biological networks are far from clear. Information processing in biological networks, like the brain, metabolic circuits, cellular-signaling circuits, etc., involves complex interactions among a large number of units (neurons, receptors). The combinatorially large number of states such a system can exist in makes it impossible to study these systems from the first principles, starting from the interactions between the basic units. The principles of collective information processing on such complex networks can be identified using coarse graining approaches. This could provide insights into the organization and function of complex biological networks. Here I study models of biological networks using continuum dynamics, renormalization, maximum likelihood estimation and information theory. Such coarse graining approaches identify features that are essential for certain processes performed by underlying biological networks. We find that long-range connections in the brain allow for global scale feature detection in a signal. These also suppress the noise and remove any gaps present in the signal. Hierarchical organization with long-range connections leads to large-scale connectivity at low synapse numbers. Time delays can be utilized to separate a mixture of signals with temporal scales. Our observations indicate that the rules in multivariate signal processing are quite different from traditional single unit signal processing.

Interplant Aboveground Signaling Prompts Upregulation of Auxin Promoter and Malate Transporter as Part of Defensive Response in the Neighboring Plants.

PubMed

Sweeney, Connor; Lakshmanan, Venkatachalam; Bais, Harsh P

2017-01-01

When disrupted by stimuli such as herbivory, pathogenic infection, or mechanical wounding, plants secrete signals such as root exudates and volatile organic compounds (VOCs). The emission of VOCs induces a response in the neighboring plant communities and can improve plant fitness by alerting nearby plants of an impending threat and prompting them to alter their physiology for defensive purposes. In this study, we investigated the role of plant-derived signals, released as a result of mechanical wounding, that may play a role in intraspecific communication between Arabidopsis thaliana communities. Plant-derived signals released by the wounded plant resulted in more elaborate root development in the neighboring, unwounded plants. Such plant-derived signals also upregulated the Aluminum-activated malate transporter ( ALMT1 ) responsible for the secretion of malic acid (MA) and the DR5 promoter, an auxin responsive promoter concentrated in root apex of the neighboring plants. We speculate that plant-derived signal-induced upregulation of root-specific ALMT1 in the undamaged neighboring plants sharing the environment with stressed plants may associate more with the benign microbes belowground. We also observed increased association of beneficial bacterium Bacillus subtilis UD1022 on roots of the neighboring plants sharing environment with the damaged plants. Wounding-induced plant-derived signals therefore induce defense mechanisms in the undamaged, local plants, eliciting a two-pronged preemptive response of more rapid root growth and up-regulation of ALMT1 , resulting in increased association with beneficial microbiome.

Laser doppler blood flow imaging using a CMOS imaging sensor with on-chip signal processing.

PubMed

He, Diwei; Nguyen, Hoang C; Hayes-Gill, Barrie R; Zhu, Yiqun; Crowe, John A; Gill, Cally; Clough, Geraldine F; Morgan, Stephen P

2013-09-18

The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF) imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.

Comparison of multichannel wide dynamic range compression and ChannelFree processing in open canal hearing instruments.

PubMed

Plyler, Patrick N; Reber, Monika Bertges; Kovach, Amanda; Galloway, Elisabeth; Humphrey, Elizabeth

2013-02-01

Multichannel wide dynamic range compression (WDRC) and ChannelFree processing have similar goals yet differ significantly in terms of signal processing. Multichannel WDRC devices divide the input signal into separate frequency bands; a separate level is determined within each frequency band; and compression in each band is based on the level within each band. ChannelFree processing detects the wideband level, and gain adjustments are based on the wideband signal level and adjusted up to 20,000 times per second. Although both signal processing strategies are currently available in hearing aids, it is unclear if differences in these signal processing strategies affect the performance and/or preference of the end user. The purpose of the research was to determine the effects of multichannel wide dynamic range compression and ChannelFree processing on performance and/or preference of listeners using open-canal hearing instruments. An experimental study in which subjects were exposed to a repeated measures design was utilized. Fourteen adult listeners with mild sloping to moderately severe sensorineural hearing loss participated (mean age 67 yr). Participants completed two 5 wk trial periods for each signal processing strategy. Probe microphone, behavioral and subjective measures were conducted unaided and aided at the end of each trial period. Behavioral and subjective results for both signal processing strategies were significantly better than unaided results; however, behavioral and subjective results were not significantly different between the signal processing strategies. Multichannel WDRC and ChannelFree processing are both effective signal processing strategies that provide significant benefit for hearing instrument users. Overall preference between the strategies may be related to the degree of hearing loss of the user, high-frequency in-situ levels, and/or acceptance of background noise. American Academy of Audiology.

NGS' GRAV-D Project Brings Advances in Aerogravimetry

NASA Astrophysics Data System (ADS)

Childers, V. A.; Preaux, S. A.; Diehl, T. M.; Li, X.; Weil, C.

2011-12-01

NOAA's National Geodetic Survey has undertaken an extensive airborne gravity campaign to help replace the nation's vertical datum by 2022. After receiving Congressional funding in FY10 &11, the GRAV-D project has now surveyed 13.45% of the total area (as of abstract submittal time). The survey has now worked on a number of aircraft, both jets and turboprops. Early work was performed at 35,000 ft and 280 kts. Since summer of 2009, the survey altitude has been lowered to 20,000 ft to enhance signal recovery and to reduce the amplitude enhancement of noise in the downward continuation needed for gravity field blending. The high altitude and speed of the survey has forced a re-evaluation of all aspects of the airborne gravity processing methodology. This presentation will update the community on the progress of the project, summarize the various processing improvements implemented, and discuss the magnitude of their effects. Improvements and research include: a new in-house gravity processing software package called "Newton", kinematic GPS processing variables and their impacts on final gravity products, and evaluation of gravimeter off-level corrections, among other topics.

Optical fiber repeatered transmission systems utilizing SAW filters

NASA Astrophysics Data System (ADS)

Rosenberg, R. L.; Ross, D. G.; Trischitta, P. R.; Fishman, D. A.; Armitage, C. B.

1983-05-01

Baseband digital transmission-line systems capable of signaling rates of several hundred to several thousand Mbit/s are presently being developed around the world. The pulse regeneration process is gated by a timing wave which is synchronous with the symbol rate of the arriving pulse stream. Synchronization is achieved by extracting a timing wave from the arriving pulse stream, itself. To date, surface acoustic-wave (SAW) filters have been widely adopted for timing recovery in the in-line regenerators of high-bit-rate systems. The present investigation has the objective to acquaint the SAW community in general, and SAW filter suppliers in particular, with the requirements for timing recovery filters in repeatered digital transmission systems. Attention is given to the system structure, the timing loop function, the system requirements affecting the timing-recovery filter, the decision process, timing jitter accumulation, the filter 'ringing' requirement, and aspects of reliability.

Overview of Recent Flight Flutter Testing Research at NASA Dryden

NASA Technical Reports Server (NTRS)

Brenner, Martin J.; Lind, Richard C.; Voracek, David F.

1997-01-01

In response to the concerns of the aeroelastic community, NASA Dryden Flight Research Center, Edwards, California, is conducting research into improving the flight flutter (including aeroservoelasticity) test process with more accurate and automated techniques for stability boundary prediction. The important elements of this effort so far include the following: (1) excitation mechanisms for enhanced vibration data to reduce uncertainty levels in stability estimates; (2) investigation of a variety of frequency, time, and wavelet analysis techniques for signal processing, stability estimation, and nonlinear identification; and (3) robust flutter boundary prediction to substantially reduce the test matrix for flutter clearance. These are critical research topics addressing the concerns of a recent AGARD Specialists' Meeting on Advanced Aeroservoelastic Testing and Data Analysis. This paper addresses these items using flight test data from the F/A-18 Systems Research Aircraft and the F/A-18 High Alpha Research Vehicle.

Disruption of the Gut Ecosystem by Antibiotics

PubMed Central

2018-01-01

The intestinal microbiota is a complex ecosystem consisting of various microorganisms that expands human genetic repertoire and therefore affects human health and disease. The metabolic processes and signal transduction pathways of the host and intestinal microorganisms are intimately linked, and abnormal progression of each process leads to changes in the intestinal environment. Alterations in microbial communities lead to changes in functional structures based on the metabolites produced in the gut, and these environmental changes result in various bacterial infections and chronic enteric inflammatory diseases. Here, we illustrate how antibiotics are associated with an increased risk of antibiotic-associated diseases by driving intestinal environment changes that favor the proliferation and virulence of pathogens. Understanding the pathogenesis caused by antibiotics would be a crucial key to the treatment of antibiotic-associated diseases by mitigating changes in the intestinal environment and restoring it to its original state. PMID:29214770

Longevity-modulating effects of symbiosis: insights from Drosophila-Wolbachia interaction.

PubMed

Maistrenko, Oleksandr M; Serga, Svitlana V; Vaiserman, Alexander M; Kozeretska, Iryna A

2016-11-01

Microbial communities are known to significantly affect various fitness components and survival of their insect hosts, including Drosophila. The composition of symbiotic microbiota has been shown to change with the host's aging. It is unclear whether these changes are caused by the aging process or, vice versa, they affect the host's aging and longevity. Recent findings indicate that fitness and lifespan of Drosophila are affected by endosymbiotic bacteria Wolbachia. These effects, however, are inconsistent and have been reported both to extend and shorten longevity. The main molecular pathways underlying the lifespan-modulating effects of Wolbachia remain unclear, however insulin/insulin-like growth factor, immune deficiency, ecdysteroid synthesis and signaling and c-Jun N-terminal kinase pathways as well as heat shock protein synthesis and autophagy have been proposed to play a role. Here we revise the current evidence that elucidates the impact of Wolbachia endosymbionts on the aging processes in Drosophila.

Angiogenesis in Spontaneous Tumors and Implications for Comparative Tumor Biology

PubMed Central

Benazzi, C.; Al-Dissi, A.; Chau, C. H.; Figg, W. D.; Sarli, G.; de Oliveira, J. T.; Gärtner, F.

2014-01-01

Blood supply is essential for development and growth of tumors and angiogenesis is the fundamental process of new blood vessel formation from preexisting ones. Angiogenesis is a prognostic indicator for a variety of tumors, and it coincides with increased shedding of neoplastic cells into the circulation and metastasis. Several molecules such as cell surface receptors, growth factors, and enzymes are involved in this process. While antiangiogenic therapy for cancer has been proposed over 20 years ago, it has garnered much controversy in recent years within the scientific community. The complex relationships between the angiogenic signaling cascade and antiangiogenic substances have indicated the angiogenic pathway as a valid target for anticancer drug development and VEGF has become the primary antiangiogenic drug target. This review discusses the basic and clinical perspectives of angiogenesis highlighting the importance of comparative biology in understanding tumor angiogenesis and the integration of these model systems for future drug development. PMID:24563633

Multichannel heterodyning for wideband interferometry, correlation and signal processing

DOEpatents

Erskine, David J.

1999-01-01

A method of signal processing a high bandwidth signal by coherently subdividing it into many narrow bandwidth channels which are individually processed at lower frequencies in a parallel manner. Autocorrelation and correlations can be performed using reference frequencies which may drift slowly with time, reducing cost of device. Coordinated adjustment of channel phases alters temporal and spectral behavior of net signal process more precisely than a channel used individually. This is a method of implementing precision long coherent delays, interferometers, and filters for high bandwidth optical or microwave signals using low bandwidth electronics. High bandwidth signals can be recorded, mathematically manipulated, and synthesized.

Multichannel heterodyning for wideband interferometry, correlation and signal processing

DOEpatents

Erskine, D.J.

1999-08-24

A method is disclosed of signal processing a high bandwidth signal by coherently subdividing it into many narrow bandwidth channels which are individually processed at lower frequencies in a parallel manner. Autocorrelation and correlations can be performed using reference frequencies which may drift slowly with time, reducing cost of device. Coordinated adjustment of channel phases alters temporal and spectral behavior of net signal process more precisely than a channel used individually. This is a method of implementing precision long coherent delays, interferometers, and filters for high bandwidth optical or microwave signals using low bandwidth electronics. High bandwidth signals can be recorded, mathematically manipulated, and synthesized. 50 figs.

US Urban Teachers' Perspectives of Culturally Competent Professional Development

ERIC Educational Resources Information Center

Flory, Sara B.; McCaughtry, Nate; Martin, Jeffrey J.; Murphy, Anne; Blum, Barbara; Wisdom, Kimberlydawn

2014-01-01

Health disparities related to food choices, nutrition behaviours and smoking habits in urban communities in the United States signal the importance of health education (HE) in schools, yet educators in urban communities face unique cultural challenges often unaddressed in professional development (PD). The purpose of this study was to use a…

Mixed Signals in California: A Mismatch between High Schools and Community Colleges. Policy Alert

ERIC Educational Resources Information Center

National Center for Public Policy and Higher Education, 2008

2008-01-01

"Policy Alert" is a publication series that summarizes important policy findings affecting the future of higher education. This issue is based on an earlier study, "Investigating the Alignment of High School and Community College Assessments in California". The "Policy Alert" summarizes the findings of the study, and…

Diversity Training for Community Aged Care Workers: An Interdisciplinary Meta-Narrative Review

ERIC Educational Resources Information Center

Meyer, Claudia; Ogrin, Rajna; Al-Zubaidi, Hamzah; Appannah, Arti; McMillan, Sally; Barrett, Elizabeth; Browning, Colette

2017-01-01

Population ageing signals the need for a responsive community aged care workforce respectful of older people's diverse healthcare needs. Person-centered care premises individual needs and preferences to enhance participation in health care. Training for diversity does not yet exist for this workforce, but is necessary to ensure appropriate care…

System and Method for Multi-Wavelength Optical Signal Detection

NASA Technical Reports Server (NTRS)

McGlone, Thomas D. (Inventor)

2017-01-01

The system and method for multi-wavelength optical signal detection enables the detection of optical signal levels significantly below those processed at the discrete circuit level by the use of mixed-signal processing methods implemented with integrated circuit technologies. The present invention is configured to detect and process small signals, which enables the reduction of the optical power required to stimulate detection networks, and lowers the required laser power to make specific measurements. The present invention provides an adaptation of active pixel networks combined with mixed-signal processing methods to provide an integer representation of the received signal as an output. The present invention also provides multi-wavelength laser detection circuits for use in various systems, such as a differential absorption light detection and ranging system.

Analysis of acoustic emission signals and monitoring of machining processes

PubMed

Govekar; Gradisek; Grabec

2000-03-01

Monitoring of a machining process on the basis of sensor signals requires a selection of informative inputs in order to reliably characterize and model the process. In this article, a system for selection of informative characteristics from signals of multiple sensors is presented. For signal analysis, methods of spectral analysis and methods of nonlinear time series analysis are used. With the aim of modeling relationships between signal characteristics and the corresponding process state, an adaptive empirical modeler is applied. The application of the system is demonstrated by characterization of different parameters defining the states of a turning machining process, such as: chip form, tool wear, and onset of chatter vibration. The results show that, in spite of the complexity of the turning process, the state of the process can be well characterized by just a few proper characteristics extracted from a representative sensor signal. The process characterization can be further improved by joining characteristics from multiple sensors and by application of chaotic characteristics.

Prediction of endoplasmic reticulum resident proteins using fragmented amino acid composition and support vector machine.

PubMed

Kumar, Ravindra; Kumari, Bandana; Kumar, Manish

2017-01-01

The endoplasmic reticulum plays an important role in many cellular processes, which includes protein synthesis, folding and post-translational processing of newly synthesized proteins. It is also the site for quality control of misfolded proteins and entry point of extracellular proteins to the secretory pathway. Hence at any given point of time, endoplasmic reticulum contains two different cohorts of proteins, (i) proteins involved in endoplasmic reticulum-specific function, which reside in the lumen of the endoplasmic reticulum, called as endoplasmic reticulum resident proteins and (ii) proteins which are in process of moving to the extracellular space. Thus, endoplasmic reticulum resident proteins must somehow be distinguished from newly synthesized secretory proteins, which pass through the endoplasmic reticulum on their way out of the cell. Approximately only 50% of the proteins used in this study as training data had endoplasmic reticulum retention signal, which shows that these signals are not essentially present in all endoplasmic reticulum resident proteins. This also strongly indicates the role of additional factors in retention of endoplasmic reticulum-specific proteins inside the endoplasmic reticulum. This is a support vector machine based method, where we had used different forms of protein features as inputs for support vector machine to develop the prediction models. During training leave-one-out approach of cross-validation was used. Maximum performance was obtained with a combination of amino acid compositions of different part of proteins. In this study, we have reported a novel support vector machine based method for predicting endoplasmic reticulum resident proteins, named as ERPred. During training we achieved a maximum accuracy of 81.42% with leave-one-out approach of cross-validation. When evaluated on independent dataset, ERPred did prediction with sensitivity of 72.31% and specificity of 83.69%. We have also annotated six different proteomes to predict the candidate endoplasmic reticulum resident proteins in them. A webserver, ERPred, was developed to make the method available to the scientific community, which can be accessed at http://proteininformatics.org/mkumar/erpred/index.html. We found that out of 124 proteins of the training dataset, only 66 proteins had endoplasmic reticulum retention signals, which shows that these signals are not an absolute necessity for endoplasmic reticulum resident proteins to remain inside the endoplasmic reticulum. This observation also strongly indicates the role of additional factors in retention of proteins inside the endoplasmic reticulum. Our proposed predictor, ERPred, is a signal independent tool. It is tuned for the prediction of endoplasmic reticulum resident proteins, even if the query protein does not contain specific ER-retention signal.

Real-time processing of EMG signals for bionic arm purposes

NASA Astrophysics Data System (ADS)

Olid Dominguez, Ferran; Wawrzyniak, Zbigniew M.

2016-09-01

This paper is connected with the problem of prostheses, that have always been a necessity for the human being. Bio-physiological signals from muscles, electromyographic signals have been collected, analyzed and processed in order to implement a real-time algorithm which is capable of differentiation of two different states of a bionic hand: open and closed. An algorithm for real-time electromyographic signal processing with almost no false positives is presented and it is explained that in bio-physiological experiments proper signal processing is of great importance.

Intelligent Signal Processing for Active Control

DTIC Science & Technology

1992-06-17

FUNDING NUMSI Intelligent Signal Processing for Active Control C-NO001489-J-1633 G. AUTHOR(S) P.A. Ramamoorthy 7. P2RFORMING ORGANIZATION NAME(S) AND...unclassified .unclassified unclassified L . I mu-. W UNIVERSITY OF CINCINNATI COLLEGE OF ENGINEERING Intelligent Signal Processing For Rctiue Control...NAURI RESEARCH Conkact No: NO1489-J-1633 P.L: P.A.imoodh Intelligent Signal Processing For Active Control 1 Executive Summary The thrust of this

Dissolved organic matter (DOM) in pore water of Arctic Ocean sediments: linking DOM molecular composition with microbial community structure

NASA Astrophysics Data System (ADS)

Rossel, P. E.; Bienhold, C.; Boetius, A.; Dittmar, T.

2016-02-01

Marine organic matter (OM) that sinks from surface waters to the seafloor is the energy and carbon source for benthic communities. These communities produce dissolved organic matter (DOM) in the process of remineralization, enriching the sediment porewater with fresh DOM compounds. In the Arctic Ocean, primary production is limited by nutrients and light and is thus strongly influenced by sea ice cover. Ice cover is expected to further decrease due to global warming, which may have important consequences for primary production and the quantity and quality of OM exported to the seafloor. This study focused on: 1) the molecular composition of the DOM in sediment pore waters of the deep Eurasian Arctic basins, 2) whether there is any relation between Arctic Ocean ice cover and DOM composition and 3) whether the DOM composition correlates with microbial community structure. Molecular data, obtained via 15 Tesla Fourier transform ion cyclotron resonance mass spectrometry, were statistically correlated with environmental parameters. The productive ice margin stations showed higher abundances of molecular formulae of peptides, unsaturated aliphatics and saturated fatty acids. This molecular trend is indicative of fresh OM and phytodetritus deposition, compared to the northernmost, ice-covered stations which had stronger aromatic signals. Benthic bacterial community structure, as assessed with the fingerprinting method ARISA, was significantly correlated with DOM molecular composition. Further analyses using Illumina next-generation sequencing will enable the taxonomic identification of specific bacterial groups and their interdependence with DOM compounds. This study contributes to the understanding of the coupling between Arctic Ocean productivity and its depositional regime, and provides first insights into potential links between microbial community structure and DOM molecular composition in Arctic sediments

Transformed Science: Overcoming Barriers of Inequality and Mistrust to Pursue the Agenda of Underrepresented Communities

NASA Astrophysics Data System (ADS)

Lyons, Renee

Educational programs created to provide opportunities for all, in reality often reflect social inequalities. Such is the case for Public Participation in Scientific Research (PPSR) Projects. PPSR projects have been proposed as an effective way to engage more diverse audiences in science, yet the demographics of PPSR participants do not correspond with the demographic makeup of the United States. The field of PPSR as a whole has struggled to recruit low SES and underrepresented populations to participate in project research efforts. This research study explores factors, which may be affecting an underrepresented community's willingness to engage in scientific research and provides advice from PPSR project leaders in the field, who have been able to engage underrepresented communities in scientific research, on how to overcome these barriers. Finally the study investigates the theoretical construct of a Third Space within a PPSR project. The research-based recommendations for PPSR projects desiring to initiate and sustain research partnerships with underrepresented communities well align with the theoretical construct of a Third Space. This study examines a specific scientific research partnership between an underrepresented community and scientific researchers to examine if and to what extent a Third Space was created. Using qualitative methods to understand interactions and processes involved in initiating and sustaining a scientific research partnership, this study provides advice on how PPSR research partnerships can engage underrepresented communities in scientific research. Study results show inequality and mistrust of powerful institutions stood as participation barriers for underrepresented community members. Despite these barriers PPSR project leaders recommend barriers can be confronted by open dialogue with communities about the abuse and alienation they have faced, by signaling respect for the community, and by entering the community through someone the community already trusts. Finally although many of the principles of a Third Space well align with the larger level of activity, which existed in the PPSR project examined in this study, study findings challenge others to critically examine assumptions behind the idea of a Third Space in PPSR and urge other PPSR project leaders towards a transformed view of science.

Using Economic Impact Models as an Educational Tool in Community Economic Development Programming: Lessons from Pennsylvania and Wisconsin.

ERIC Educational Resources Information Center

Shields, Martin; Deller, Steven C.

2003-01-01

Outlines an educational process designed to help provide communities with economic, social, and political information using community economic impact modeling. Describes the process of community meetings using economic impact, community demographics, and fiscal impact modules and the local preconditions that help make the process successful. (SK)

Probe for optically monitoring progress of in-situ vitrification of soil

DOEpatents

Timmerman, Craig L.; Oma, Kenton H.; Davis, Karl C.

1988-01-01

A detector system for sensing the progress of an ISV process along an expected path comprises multiple sensors each having an input port. The input ports are distributed along the expected path of the ISV process between a starting location and an expected ending location. Each sensor generates an electrical signal representative of the temperature in the vicinity of its input port. A signal processor is coupled to the sensors to receive an electrical signal generated by a sensor, and generate a signal which is encoded with information which identifies the sensor and whether the ISV process has reached the sensor's input port. A transmitter propagates the encoded signal. The signal processor and the transmitter are below ground at a location beyond the expected ending location of the ISV process in the direction from the starting location to the expected ending location. A signal receiver and a decoder are located above ground for receiving the encoded signal propagated by the transmitter, decoding the encoded signal and providing a human-perceptible indication of the progress of the ISV process.

Probe for optically monitoring progress of in-situ vitrification of soil

DOEpatents

Timmerman, C.L.; Oma, K.H.; Davis, K.C.

1988-08-09

A detector system for sensing the progress of an ISV process along an expected path comprises multiple sensors each having an input port. The input ports are distributed along the expected path of the ISV process between a starting location and an expected ending location. Each sensor generates an electrical signal representative of the temperature in the vicinity of its input port. A signal processor is coupled to the sensors to receive an electrical signal generated by a sensor, and generate a signal which is encoded with information which identifies the sensor and whether the ISV process has reached the sensor's input port. A transmitter propagates the encoded signal. The signal processor and the transmitter are below ground at a location beyond the expected ending location of the ISV process in the direction from the starting location to the expected ending location. A signal receiver and a decoder are located above ground for receiving the encoded signal propagated by the transmitter, decoding the encoded signal and providing a human-perceptible indication of the progress of the ISV process. 7 figs.

Measuring disaster-resilient communities: a case study of coastal communities in Indonesia.

PubMed

Kafle, Shesh Kanta

2012-01-01

Vulnerability reduction and resilience building of communities are central concepts in recent policy debates. Although there are fundamental linkages, and complementarities exist between the two concepts, recent policy and programming has focused more on the latter. It is assumed here that reducing underlying causes of vulnerabilities and their interactions with resilience elements is a prerequisite for obtaining resilience capabilities. An integrated approach, incorporating both the vulnerability and resilience considerations, has been taken while developing an index for measuring disaster-resilient communities. This study outlines a method for measuring community resilience capabilities using process and outcome indicators in 43 coastal communities in Indonesia. An index was developed using ten process and 25 outcome indicators, selected on the basis of the ten steps of the Integrated Community Based Risk Reduction (ICBRR) process, and key characteristics of disaster resilient communities were taken from various literatures. The overall index value of all 43 communities was 63, whereas the process and outcome indicator values were measured as 63 and 61.5 respectively. The core components of this index are process and outcome indicators. The tool has been developed with an assumption that both the process and outcome indicators are equally important in building disaster-resilient communities. The combination of both indicators is an impetus to quality change in the community. Process indicators are important for community understanding, ownership and the sustainability of the programme; whereas outcome indicators are important for the real achievements in terms of community empowerment and capacity development. The process of ICBRR approach varies by country and location as per the level of community awareness and organisational strategy. However, core elements such as the formation of community groups, mobilising those groups in risk assessment and planning should be present in all the countries or locations. As this study shows, community resiliency can be measured but any such measurement must be both location- and hazard-specific.

Computational Analysis of Residue Interaction Networks and Coevolutionary Relationships in the Hsp70 Chaperones: A Community-Hopping Model of Allosteric Regulation and Communication

PubMed Central

Stetz, Gabrielle; Verkhivker, Gennady M.

2017-01-01

Allosteric interactions in the Hsp70 proteins are linked with their regulatory mechanisms and cellular functions. Despite significant progress in structural and functional characterization of the Hsp70 proteins fundamental questions concerning modularity of the allosteric interaction networks and hierarchy of signaling pathways in the Hsp70 chaperones remained largely unexplored and poorly understood. In this work, we proposed an integrated computational strategy that combined atomistic and coarse-grained simulations with coevolutionary analysis and network modeling of the residue interactions. A novel aspect of this work is the incorporation of dynamic residue correlations and coevolutionary residue dependencies in the construction of allosteric interaction networks and signaling pathways. We found that functional sites involved in allosteric regulation of Hsp70 may be characterized by structural stability, proximity to global hinge centers and local structural environment that is enriched by highly coevolving flexible residues. These specific characteristics may be necessary for regulation of allosteric structural transitions and could distinguish regulatory sites from nonfunctional conserved residues. The observed confluence of dynamics correlations and coevolutionary residue couplings with global networking features may determine modular organization of allosteric interactions and dictate localization of key mediating sites. Community analysis of the residue interaction networks revealed that concerted rearrangements of local interacting modules at the inter-domain interface may be responsible for global structural changes and a population shift in the DnaK chaperone. The inter-domain communities in the Hsp70 structures harbor the majority of regulatory residues involved in allosteric signaling, suggesting that these sites could be integral to the network organization and coordination of structural changes. Using a network-based formalism of allostery, we introduced a community-hopping model of allosteric communication. Atomistic reconstruction of signaling pathways in the DnaK structures captured a direction-specific mechanism and molecular details of signal transmission that are fully consistent with the mutagenesis experiments. The results of our study reconciled structural and functional experiments from a network-centric perspective by showing that global properties of the residue interaction networks and coevolutionary signatures may be linked with specificity and diversity of allosteric regulation mechanisms. PMID:28095400

Computational Analysis of Residue Interaction Networks and Coevolutionary Relationships in the Hsp70 Chaperones: A Community-Hopping Model of Allosteric Regulation and Communication.

PubMed

Stetz, Gabrielle; Verkhivker, Gennady M

2017-01-01

Allosteric interactions in the Hsp70 proteins are linked with their regulatory mechanisms and cellular functions. Despite significant progress in structural and functional characterization of the Hsp70 proteins fundamental questions concerning modularity of the allosteric interaction networks and hierarchy of signaling pathways in the Hsp70 chaperones remained largely unexplored and poorly understood. In this work, we proposed an integrated computational strategy that combined atomistic and coarse-grained simulations with coevolutionary analysis and network modeling of the residue interactions. A novel aspect of this work is the incorporation of dynamic residue correlations and coevolutionary residue dependencies in the construction of allosteric interaction networks and signaling pathways. We found that functional sites involved in allosteric regulation of Hsp70 may be characterized by structural stability, proximity to global hinge centers and local structural environment that is enriched by highly coevolving flexible residues. These specific characteristics may be necessary for regulation of allosteric structural transitions and could distinguish regulatory sites from nonfunctional conserved residues. The observed confluence of dynamics correlations and coevolutionary residue couplings with global networking features may determine modular organization of allosteric interactions and dictate localization of key mediating sites. Community analysis of the residue interaction networks revealed that concerted rearrangements of local interacting modules at the inter-domain interface may be responsible for global structural changes and a population shift in the DnaK chaperone. The inter-domain communities in the Hsp70 structures harbor the majority of regulatory residues involved in allosteric signaling, suggesting that these sites could be integral to the network organization and coordination of structural changes. Using a network-based formalism of allostery, we introduced a community-hopping model of allosteric communication. Atomistic reconstruction of signaling pathways in the DnaK structures captured a direction-specific mechanism and molecular details of signal transmission that are fully consistent with the mutagenesis experiments. The results of our study reconciled structural and functional experiments from a network-centric perspective by showing that global properties of the residue interaction networks and coevolutionary signatures may be linked with specificity and diversity of allosteric regulation mechanisms.

Kepler eclipsing binary stars. IV. Precise eclipse times for close binaries and identification of candidate three-body systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conroy, Kyle E.; Stassun, Keivan G.; Prša, Andrej

2014-02-01

We present a catalog of precise eclipse times and analysis of third-body signals among 1279 close binaries in the latest Kepler Eclipsing Binary Catalog. For these short-period binaries, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the eclipse timings. We present a method to measure precise eclipse times in the presence of distorted light curves, such as in contact and near-contact binaries which exhibit continuously changing light levelsmore » in and out of eclipse. We identify 236 systems for which we find a timing variation signal compatible with the presence of a third body. These are modeled for the light travel time effect and the basic properties of the third body are derived. This study complements J. A. Orosz et al. (in preparation), which focuses on eclipse timing variations of longer period binaries with flat out-of-eclipse regions. Together, these two papers provide comprehensive eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an ongoing resource freely accessible online to the community.« less

Theoretical and experimental study on PMD-supported transmission using polarization diversity in coherent optical OFDM systems.

PubMed

Shieh, W; Yi, X; Ma, Y; Tang, Y

2007-08-06

In this paper, we conduct theoretical and experimental study on the PMD-supported transmission with coherent optical orthogonal frequency-division multiplexing (CO-OFDM). We first present the model for the optical fiber communication channel in the presence of the polarization effects. It shows that the optical fiber channel model can be treated as a special kind of multiple-input multiple-output (MIMO) model, namely, a two-input two-output (TITO) model which is intrinsically represented by a two-element Jones vector familiar to the optical communications community. The detailed discussions on various coherent optical MIMO-OFDM (CO-MIMO-OFDM) models are presented. Furthermore, we show the first experiment of polarization-diversity detection in CO-OFDM systems. In particular, a CO-OFDM signal at 10.7 Gb/s is successfully recovered after 900 ps differential-group-delay (DGD) and 1000-km transmission through SSMF fiber without optical dispersion compensation. The transmission experiment with higher-order PMD further confirms the immunity of the CO-OFDM signal to PMD in the transmission fiber. The nonlinearity performance of PMD-supported transmission is also reported. For the first time, nonlinear phase noise mitigation based on receiver digital signal processing is experimentally demonstrated for CO-OFDM transmission.

Frequency domain laser velocimeter signal processor: A new signal processing scheme

NASA Technical Reports Server (NTRS)

Meyers, James F.; Clemmons, James I., Jr.

1987-01-01

A new scheme for processing signals from laser velocimeter systems is described. The technique utilizes the capabilities of advanced digital electronics to yield a smart instrument that is able to configure itself, based on the characteristics of the input signals, for optimum measurement accuracy. The signal processor is composed of a high-speed 2-bit transient recorder for signal capture and a combination of adaptive digital filters with energy and/or zero crossing detection signal processing. The system is designed to accept signals with frequencies up to 100 MHz with standard deviations up to 20 percent of the average signal frequency. Results from comparative simulation studies indicate measurement accuracies 2.5 times better than with a high-speed burst counter, from signals with as few as 150 photons per burst.

Novel sonar signal processing tool using Shannon entropy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quazi, A.H.

1996-06-01

Traditionally, conventional signal processing extracts information from sonar signals using amplitude, signal energy or frequency domain quantities obtained using spectral analysis techniques. The object is to investigate an alternate approach which is entirely different than that of traditional signal processing. This alternate approach is to utilize the Shannon entropy as a tool for the processing of sonar signals with emphasis on detection, classification, and localization leading to superior sonar system performance. Traditionally, sonar signals are processed coherently, semi-coherently, and incoherently, depending upon the a priori knowledge of the signals and noise. Here, the detection, classification, and localization technique will bemore » based on the concept of the entropy of the random process. Under a constant energy constraint, the entropy of a received process bearing finite number of sample points is maximum when hypothesis H{sub 0} (that the received process consists of noise alone) is true and decreases when correlated signal is present (H{sub 1}). Therefore, the strategy used for detection is: (I) Calculate the entropy of the received data; then, (II) compare the entropy with the maximum value; and, finally, (III) make decision: H{sub 1} is assumed if the difference is large compared to pre-assigned threshold and H{sub 0} is otherwise assumed. The test statistics will be different between entropies under H{sub 0} and H{sub 1}. Here, we shall show the simulated results for detecting stationary and non-stationary signals in noise, and results on detection of defects in a Plexiglas bar using an ultrasonic experiment conducted by Hughes. {copyright} {ital 1996 American Institute of Physics.}« less

A fully reconfigurable photonic integrated signal processor

NASA Astrophysics Data System (ADS)

Liu, Weilin; Li, Ming; Guzzon, Robert S.; Norberg, Erik J.; Parker, John S.; Lu, Mingzhi; Coldren, Larry A.; Yao, Jianping

2016-03-01

Photonic signal processing has been considered a solution to overcome the inherent electronic speed limitations. Over the past few years, an impressive range of photonic integrated signal processors have been proposed, but they usually offer limited reconfigurability, a feature highly needed for the implementation of large-scale general-purpose photonic signal processors. Here, we report and experimentally demonstrate a fully reconfigurable photonic integrated signal processor based on an InP-InGaAsP material system. The proposed photonic signal processor is capable of performing reconfigurable signal processing functions including temporal integration, temporal differentiation and Hilbert transformation. The reconfigurability is achieved by controlling the injection currents to the active components of the signal processor. Our demonstration suggests great potential for chip-scale fully programmable all-optical signal processing.

User's manual SIG: a general-purpose signal processing program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lager, D.; Azevedo, S.

1983-10-25

SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time- and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Many of the basic operations one would perform on digitized data are contained in the core SIG package. Out of these core commands, more powerful signal processing algorithms may be built. Many different operations on time- and frequency-domain signals can be performed by SIG. They include operations on the samples of a signal, such as adding a scalar tomore » each sample, operations on the entire signal such as digital filtering, and operations on two or more signals such as adding two signals. Signals may be simulated, such as a pulse train or a random waveform. Graphics operations display signals and spectra.« less

Costs and effects of a 'healthy living' approach to community development in two deprived communities: findings from a mixed methods study

PubMed Central

2011-01-01

Background Inequalities in health have proved resistant to 'top down' approaches. It is increasingly recognised that health promotion initiatives are unlikely to succeed without strong local involvement at all stages of the process and many programmes now use grass roots approaches. A healthy living approach to community development (HLA) was developed as an innovative response to local concerns about a lack of appropriate services in two deprived communities in Pembrokeshire, West Wales. We sought to assess feasibility, costs, benefits and working relationships of this HLA. Methods The HLA intervention operated through existing community forums and focused on the whole community and its relationship with statutory and voluntary sectors. Local people were trained as community researchers and gathered views about local needs though resident interviews. Forums used interview results to write action plans, disseminated to commissioning organisations. The process was supported throughout through the project. The evaluation used a multi-method before and after study design including process and outcome formative and summative evaluation; data gathered through documentary evidence, diaries and reflective accounts, semi-structured interviews, focus groups and costing proformas. Main outcome measures were processes and timelines of implementation of HLA; self reported impact on communities and participants; community-agency processes of liaison; costs. Results Communities were able to produce and disseminate action plans based on locally-identified needs. The process was slower than anticipated: few community changes had occurred but expectations were high. Community participants gained skills and confidence. Cross-sector partnership working developed. The process had credibility within service provider organisations but mechanisms for refocusing commissioning were patchy. Intervention costs averaged £58,304 per community per annum. Conclusions The intervention was feasible and inexpensive, with indications of potential impact at individual, community and policy planning levels. However, it is a long term process which requires sustained investment and must be embedded in planning and service delivery processes. PMID:21223586

Dissemination as Dialogue: Building Trust and Sharing Research Findings Through Community Engagement.

PubMed

McDavitt, Bryce; Bogart, Laura M; Mutchler, Matt G; Wagner, Glenn J; Green, Harold D; Lawrence, Sean Jamar; Mutepfa, Kieta D; Nogg, Kelsey A

2016-03-17

A fundamental feature of community-based participatory research (CBPR) is sharing findings with community members and engaging community partners in the dissemination process. To be truly collaborative, dissemination should involve community members in a two-way dialogue about new research findings. Yet little literature describes how to engage communities in dialogue about research findings, especially with historically marginalized communities where mistrust of researchers may exist because of past or present social injustices. Through a series of interactive community presentations on findings from a longitudinal study, we developed a process for community dissemination that involved several overlapping phases: planning, outreach, content development, interactive presentations, and follow-up. Through this process, we built on existing and new community relationships. Following each interactive presentation, the research team debriefed and reviewed notes to identify lessons learned from the process. Key themes included the importance of creating a flexible dissemination plan, tailoring presentations to each community group, establishing a point person to serve as a community liaison, and continuing dialogue with community members after the presentations. Core strategies for developing trust during dissemination included engaging community members at every step, reserving ample time for discussion during presentations, building rapport by sharing personal experiences, being receptive to and learning from criticism, and implementing input from community members. This process led to a deeper understanding of research findings and ensured that results reached community members who were invested in them.

Dissemination as Dialogue: Building Trust and Sharing Research Findings Through Community Engagement

PubMed Central

Bogart, Laura M.; Mutchler, Matt G.; Wagner, Glenn J.; Green, Harold D.; Lawrence, Sean Jamar; Mutepfa, Kieta D.; Nogg, Kelsey A.

2016-01-01

A fundamental feature of community-based participatory research (CBPR) is sharing findings with community members and engaging community partners in the dissemination process. To be truly collaborative, dissemination should involve community members in a two-way dialogue about new research findings. Yet little literature describes how to engage communities in dialogue about research findings, especially with historically marginalized communities where mistrust of researchers may exist because of past or present social injustices. Through a series of interactive community presentations on findings from a longitudinal study, we developed a process for community dissemination that involved several overlapping phases: planning, outreach, content development, interactive presentations, and follow-up. Through this process, we built on existing and new community relationships. Following each interactive presentation, the research team debriefed and reviewed notes to identify lessons learned from the process. Key themes included the importance of creating a flexible dissemination plan, tailoring presentations to each community group, establishing a point person to serve as a community liaison, and continuing dialogue with community members after the presentations. Core strategies for developing trust during dissemination included engaging community members at every step, reserving ample time for discussion during presentations, building rapport by sharing personal experiences, being receptive to and learning from criticism, and implementing input from community members. This process led to a deeper understanding of research findings and ensured that results reached community members who were invested in them. PMID:26986541

Gas turbine engine control system

NASA Technical Reports Server (NTRS)

Idelchik, Michael S. (Inventor)

1991-01-01

A control system and method of controlling a gas turbine engine. The control system receives an error signal and processes the error signal to form a primary fuel control signal. The control system also receives at least one anticipatory demand signal and processes the signal to form an anticipatory fuel control signal. The control system adjusts the value of the anticipatory fuel control signal based on the value of the error signal to form an adjusted anticipatory signal and then the adjusted anticipatory fuel control signal and the primary fuel control signal are combined to form a fuel command signal.

Electronic filters, signal conversion apparatus, hearing aids and methods

NASA Technical Reports Server (NTRS)

Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

1994-01-01

An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed.

Searching for links in the biotic characteristics and abiotic parameters of nine different biogas plants

PubMed Central

Walter, Andreas; Knapp, Brigitte A.; Farbmacher, Theresa; Ebner, Christian; Insam, Heribert; Franke‐Whittle, Ingrid H.

2012-01-01

Summary To find links between the biotic characteristics and abiotic process parameters in anaerobic digestion systems, the microbial communities of nine full‐scale biogas plants in South Tyrol (Italy) and Vorarlberg (Austria) were investigated using molecular techniques and the physical and chemical properties were monitored. DNA from sludge samples was subjected to microarray hybridization with the ANAEROCHIP microarray and results indicated that sludge samples grouped into two main clusters, dominated either by Methanosarcina or by Methanosaeta, both aceticlastic methanogens. Hydrogenotrophic methanogens were hardly detected or if detected, gave low hybridization signals. Results obtained using denaturing gradient gel electrophoresis (DGGE) supported the findings of microarray hybridization. Real‐time PCR targeting Methanosarcina and Methanosaeta was conducted to provide quantitative data on the dominating methanogens. Correlation analysis to determine any links between the microbial communities found by microarray analysis, and the physicochemical parameters investigated was conducted. It was shown that the sludge samples dominated by the genus Methanosarcina were positively correlated with higher concentrations of acetate, whereas sludge samples dominated by representatives of the genus Methanosaeta had lower acetate concentrations. No other correlations between biotic characteristics and abiotic parameters were found. Methanogenic communities in each reactor were highly stable and resilient over the whole year. PMID:22950603

Music to knowledge: A visual programming environment for the development and evaluation of music information retrieval techniques

NASA Astrophysics Data System (ADS)

Ehmann, Andreas F.; Downie, J. Stephen

2005-09-01

The objective of the International Music Information Retrieval Systems Evaluation Laboratory (IMIRSEL) project is the creation of a large, secure corpus of audio and symbolic music data accessible to the music information retrieval (MIR) community for the testing and evaluation of various MIR techniques. As part of the IMIRSEL project, a cross-platform JAVA based visual programming environment called Music to Knowledge (M2K) is being developed for a variety of music information retrieval related tasks. The primary objective of M2K is to supply the MIR community with a toolset that provides the ability to rapidly prototype algorithms, as well as foster the sharing of techniques within the MIR community through the use of a standardized set of tools. Due to the relatively large size of audio data and the computational costs associated with some digital signal processing and machine learning techniques, M2K is also designed to support distributed computing across computing clusters. In addition, facilities to allow the integration of non-JAVA based (e.g., C/C++, MATLAB, etc.) algorithms and programs are provided within M2K. [Work supported by the Andrew W. Mellon Foundation and NSF Grants No. IIS-0340597 and No. IIS-0327371.

Design of signal reception and processing system of embedded ultrasonic endoscope

NASA Astrophysics Data System (ADS)

Li, Ming; Yu, Feng; Zhang, Ruiqiang; Li, Yan; Chen, Xiaodong; Yu, Daoyin

2009-11-01

Embedded Ultrasonic Endoscope, based on embedded microprocessor and embedded real-time operating system, sends a micro ultrasonic probe into coelom through the biopsy channel of the Electronic Endoscope to get the fault histology features of digestive organs by rotary scanning, and acquires the pictures of the alimentary canal mucosal surface. At the same time, ultrasonic signals are processed by signal reception and processing system, forming images of the full histology of the digestive organs. Signal Reception and Processing System is an important component of Embedded Ultrasonic Endoscope. However, the traditional design, using multi-level amplifiers and special digital processing circuits to implement signal reception and processing, is no longer satisfying the standards of high-performance, miniaturization and low power requirements that embedded system requires, and as a result of the high noise that multi-level amplifier brought, the extraction of small signal becomes hard. Therefore, this paper presents a method of signal reception and processing based on double variable gain amplifier and FPGA, increasing the flexibility and dynamic range of the Signal Reception and Processing System, improving system noise level, and reducing power consumption. Finally, we set up the embedded experiment system, using a transducer with the center frequency of 8MHz to scan membrane samples, and display the image of ultrasonic echo reflected by each layer of membrane, with a frame rate of 5Hz, verifying the correctness of the system.

Punch stretching process monitoring using acoustic emission signal analysis. II - Application of frequency domain deconvolution

NASA Technical Reports Server (NTRS)

Liang, Steven Y.; Dornfeld, David A.; Nickerson, Jackson A.

1987-01-01

The coloring effect on the acoustic emission signal due to the frequency response of the data acquisition/processing instrumentation may bias the interpretation of AE signal characteristics. In this paper, a frequency domain deconvolution technique, which involves the identification of the instrumentation transfer functions and multiplication of the AE signal spectrum by the inverse of these system functions, has been carried out. In this way, the change in AE signal characteristics can be better interpreted as the result of the change in only the states of the process. Punch stretching process was used as an example to demonstrate the application of the technique. Results showed that, through the deconvolution, the frequency characteristics of AE signals generated during the stretching became more distinctive and can be more effectively used as tools for process monitoring.

A microcomputer based frequency-domain processor for laser Doppler anemometry

NASA Technical Reports Server (NTRS)

Horne, W. Clifton; Adair, Desmond

1988-01-01

A prototype multi-channel laser Doppler anemometry (LDA) processor was assembled using a wideband transient recorder and a microcomputer with an array processor for fast Fourier transform (FFT) computations. The prototype instrument was used to acquire, process, and record signals from a three-component wind tunnel LDA system subject to various conditions of noise and flow turbulence. The recorded data was used to evaluate the effectiveness of burst acceptance criteria, processing algorithms, and selection of processing parameters such as record length. The recorded signals were also used to obtain comparative estimates of signal-to-noise ratio between time-domain and frequency-domain signal detection schemes. These comparisons show that the FFT processing scheme allows accurate processing of signals for which the signal-to-noise ratio is 10 to 15 dB less than is practical using counter processors.

Process Dissociation and Mixture Signal Detection Theory

ERIC Educational Resources Information Center

DeCarlo, Lawrence T.

2008-01-01

The process dissociation procedure was developed in an attempt to separate different processes involved in memory tasks. The procedure naturally lends itself to a formulation within a class of mixture signal detection models. The dual process model is shown to be a special case. The mixture signal detection model is applied to data from a widely…

Platform for Post-Processing Waveform-Based NDE

NASA Technical Reports Server (NTRS)

Roth, Don J.

2010-01-01

Signal- and image-processing methods are commonly needed to extract information from the waves, improve resolution of, and highlight defects in an image. Since some similarity exists for all waveform-based nondestructive evaluation (NDE) methods, it would seem that a common software platform containing multiple signal- and image-processing techniques to process the waveforms and images makes sense where multiple techniques, scientists, engineers, and organizations are involved. NDE Wave & Image Processor Version 2.0 software provides a single, integrated signal- and image-processing and analysis environment for total NDE data processing and analysis. It brings some of the most useful algorithms developed for NDE over the past 20 years into a commercial-grade product. The software can import signal/spectroscopic data, image data, and image series data. This software offers the user hundreds of basic and advanced signal- and image-processing capabilities including esoteric 1D and 2D wavelet-based de-noising, de-trending, and filtering. Batch processing is included for signal- and image-processing capability so that an optimized sequence of processing operations can be applied to entire folders of signals, spectra, and images. Additionally, an extensive interactive model-based curve-fitting facility has been included to allow fitting of spectroscopy data such as from Raman spectroscopy. An extensive joint-time frequency module is included for analysis of non-stationary or transient data such as that from acoustic emission, vibration, or earthquake data.

Effects of jasmonic acid, ethylene, and salicylic acid signaling on the rhizosphere bacterial community of Arabidopsis thaliana.

PubMed

Doornbos, Rogier F; Geraats, Bart P J; Kuramae, Eiko E; Van Loon, L C; Bakker, Peter A H M

2011-04-01

Systemically induced resistance is a promising strategy to control plant diseases, as it affects numerous pathogens. However, since induced resistance reduces one or both growth and activity of plant pathogens, the indigenous microflora may also be affected by an enhanced defensive state of the plant. The aim of this study was to elucidate how much the bacterial rhizosphere microflora of Arabidopsis is affected by induced systemic resistance (ISR) or systemic acquired resistance (SAR). Therefore, the bacterial microflora of wild-type plants and plants affected in their defense signaling was compared. Additionally, ISR was induced by application of methyl jasmonate and SAR by treatment with salicylic acid or benzothiadiazole. As a comparative model, we also used wild type and ethylene-insensitive tobacco. Some of the Arabidopsis genotypes affected in defense signaling showed altered numbers of culturable bacteria in their rhizospheres; however, effects were dependent on soil type. Effects of plant genotype on rhizosphere bacterial community structure could not be related to plant defense because chemical activation of ISR or SAR had no significant effects on density and structure of the rhizosphere bacterial community. These findings support the notion that control of plant diseases by elicitation of systemic resistance will not significantly affect the resident soil bacterial microflora.

Charcoal disrupts cell-cell communication through multiple mechanisms

NASA Astrophysics Data System (ADS)

Gao, X.; Cheng, H. Y.; Liu, S.; Masiello, C. A.; Silberg, J. J.; Del Valle, I.

2016-12-01

Microbial cell-cell communication through the release and detection of small signaling molecules is employed by soil microbes to manage many biogeochemically relevant processes including production of biofilms, priming effects on native SOM, and management of methanogenesis and denitrification. Charcoal is a ubiquitous component of soil, entering soil either from natural fire or intentionally amended as biochar. Charcoal's presence in soil introduces spatial and temporal heterogeneity in nutrients and habitats for soil microbes and may trigger a range of biological effects not yet predictable, in part because it interferes with microbial cell-cell communication. We hypothesized that charcoal's alkalinity and large active surface area could affect the lifetime of some chemical compounds that microbes use for cell-cell signaling on times scales relevant to growth and communication. To test this idea, we examined the extent and rate of charcoal quenching of cell-cell communication caused by ten charcoals with a wide range of physicochemical properties. Our measurements focused on signaling mediated by an acyl-homoserine lactone (AHL), N-3-oxo-dodecanoyl-L-homoserine lactone, which is used by many gram-negative bacteria for quorum sensing. Our results from a bioassay and chemical sorption experiments revealed that charcoal can decrease the bioavailable level of AHL through a combination of sorption and pH-dependent hydrolysis of the lactone ring. We found that the kinetics of hydrolysis can exceed those of sorption. These findings implicate charcoal surface area and alkalinity as properties that could be tuned to regulate the degradation rates of cell-cell signaling molecules in soils. We then built a quantitative model that predicts the half-lives of different microbial signaling compounds in the presence of charcoals varying in pH and surface area. Our model results suggest that the effects of charcoal on pH-sensitive bacterial AHL signals will be fundamentally distinct from effects on pH-insensitive fungal signals, potentially leading to shifts in microbial community structures.

Severe weather investigation using GNSS signals - a new dimension of GNSS meteorology

NASA Astrophysics Data System (ADS)

Rohm, W.; Zhang, K.; Choy, S.; Kuleshov, Y.; Bosy, J.; Kroszczyński, K.

2012-04-01

The Global Navigation Satellite Systems (GNSS) signals transmitted from satellites are subjected to atmospheric delays since the signals have to propagate through different layers of the atmosphere before GNSS receiver receives them. Two major distinctive effects according to the nature of the impact on the signal propagation are the ionosphere which is a dispersive media and the troposphere which is a non-dispersive layer. In this study, our focus of research is concentrated on the troposphere and the severe weather phenomena caused by midlatitude cyclonic storms. GNSS tomography technique is used to investigate both the spatial and temporal structures of a cyclonic storm. New algorithms will be developed based on optimal integrations of various observation techniques, such as ground-based meteorological measurements, radiosonde data, numerical weather prediction (NWP) models, GNSS radio occultation (RO) profiles. Our initial results suggest that the ground-based GNSS CORS stations will play a major role in the integration process. The structure and distribution of the GNSS CORS network and satellite constellations in context of size and resolution of tomography model are investigated along with the a priori information required, observation and estimation time interval and precision and accuracy needs. A number of numerical analyses are carried out using actual measurements in different parts of the world to evaluate the new algorithms developed through international collaboration. It is expected that GNSS tomography with a number of integrated measurements will provide an important insight into the vertical as well as the horizontal structure of different kinds of severe weather phenomena. It is also expected that GNSS tomography will become an important tool for the study of the severe weather processes, such as the development, maturation, and dissipation stages, which is complementary to other meteorological techniques such as weather radars and microwave radiometers. Potential usages of the new technique in real and/or near-real time would provide an exciting opportunity to launch monitoring and warning services that are able to offer vital information for community and decision makers.

Community Leadership through Community-Based Programming: The Role of the Community College.

ERIC Educational Resources Information Center

Boone, Edgar J.; And Others

Organized around 15 tasks involved in the community-based programming (CBP) process, this book provides practical, field-tested guidance on successfully implementing CBP in community colleges. Following prefatory materials, the following chapters are provided: (1) "An Introduction to the Community-Based Programming Process" (Edgar J.…

Cohorts and community: a case study of community engagement in the establishment of a health and demographic surveillance site in Malaysia

PubMed Central

Allotey, Pascale; Reidpath, Daniel D.; Devarajan, Nirmala; Rajagobal, Kanason; Yasin, Shajahan; Arunachalam, Dharmalingam; Imelda, Johanna Debora; Soyiri, Ireneous; Davey, Tamzyn; Jahan, Nowrozy

2014-01-01

Background Community engagement is an increasingly important requirement of public health research and plays an important role in the informed consent and recruitment process. However, there is very little guidance about how it should be done, the indicators for assessing effectiveness of the community engagement process and the impact it has on recruitment, retention, and ultimately on the quality of the data collected as part of longitudinal cohort studies. Methods An instrumental case study approach, with data from field notes, policy documents, unstructured interviews, and focus group discussions with key community stakeholders and informants, was used to explore systematically the implementation and outcomes of the community engagement strategy for recruitment of an entire community into a demographic and health surveillance site in Malaysia. Results For a dynamic cohort, community engagement needs to be an ongoing process. The community engagement process has likely helped to facilitate the current response rate of 85% in the research communities. The case study highlights the importance of systematic documentation of the community engagement process to ensure an understanding of the effects of the research on recruitment and the community. Conclusions A critical lesson from the case study data is the importance of relationships in the recruitment process for large population-based studies, and the need for ongoing documentation and analysis of the impact of cumulative interactions between research and community engagement. PMID:24804983

Collective efficacy in Denver, Colorado: Strengthening neighborhoods and health through community gardens.

PubMed

Teig, Ellen; Amulya, Joy; Bardwell, Lisa; Buchenau, Michael; Marshall, Julie A; Litt, Jill S

2009-12-01

Community gardens are viewed as a potentially useful environmental change strategy to promote active and healthy lifestyles but the scientific evidence base for gardens is limited. As a step towards understanding whether gardens are a viable health promotion strategy for local communities, we set out to examine the social processes that might explain the connection between gardens, garden participation and health. We analyzed data from semi-structured interviews with community gardeners in Denver. The analysis examined social processes described by community gardeners and how those social processes were cultivated by or supportive of activities in community gardens. After presenting results describing these social processes and the activities supporting them, we discuss the potential for the place-based social processes found in community gardens to support collective efficacy, a powerful mechanism for enhancing the role of gardens in promoting health.

Modeling laser velocimeter signals as triply stochastic Poisson processes

NASA Technical Reports Server (NTRS)

Mayo, W. T., Jr.

1976-01-01

Previous models of laser Doppler velocimeter (LDV) systems have not adequately described dual-scatter signals in a manner useful for analysis and simulation of low-level photon-limited signals. At low photon rates, an LDV signal at the output of a photomultiplier tube is a compound nonhomogeneous filtered Poisson process, whose intensity function is another (slower) Poisson process with the nonstationary rate and frequency parameters controlled by a random flow (slowest) process. In the present paper, generalized Poisson shot noise models are developed for low-level LDV signals. Theoretical results useful in detection error analysis and simulation are presented, along with measurements of burst amplitude statistics. Computer generated simulations illustrate the difference between Gaussian and Poisson models of low-level signals.

Real-time holographic surveillance system

DOEpatents

Collins, H. Dale; McMakin, Douglas L.; Hall, Thomas E.; Gribble, R. Parks

1995-01-01

A holographic surveillance system including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm.

A conceptual framework for invasion in microbial communities.

PubMed

Kinnunen, Marta; Dechesne, Arnaud; Proctor, Caitlin; Hammes, Frederik; Johnson, David; Quintela-Baluja, Marcos; Graham, David; Daffonchio, Daniele; Fodelianakis, Stilianos; Hahn, Nicole; Boon, Nico; Smets, Barth F

2016-12-01

There is a growing interest in controlling-promoting or avoiding-the invasion of microbial communities by new community members. Resource availability and community structure have been reported as determinants of invasion success. However, most invasion studies do not adhere to a coherent and consistent terminology nor always include rigorous interpretations of the processes behind invasion. Therefore, we suggest that a consistent set of definitions and a rigorous conceptual framework are needed. We define invasion in a microbial community as the establishment of an alien microbial type in a resident community and argue how simple criteria to define aliens, residents, and alien establishment can be applied for a wide variety of communities. In addition, we suggest an adoption of the community ecology framework advanced by Vellend (2010) to clarify potential determinants of invasion. This framework identifies four fundamental processes that control community dynamics: dispersal, selection, drift and diversification. While selection has received ample attention in microbial community invasion research, the three other processes are often overlooked. Here, we elaborate on the relevance of all four processes and conclude that invasion experiments should be designed to elucidate the role of dispersal, drift and diversification, in order to obtain a complete picture of invasion as a community process.

A conceptual framework for invasion in microbial communities

PubMed Central

Kinnunen, Marta; Dechesne, Arnaud; Proctor, Caitlin; Hammes, Frederik; Johnson, David; Quintela-Baluja, Marcos; Graham, David; Daffonchio, Daniele; Fodelianakis, Stilianos; Hahn, Nicole; Boon, Nico; Smets, Barth F

2016-01-01

There is a growing interest in controlling—promoting or avoiding—the invasion of microbial communities by new community members. Resource availability and community structure have been reported as determinants of invasion success. However, most invasion studies do not adhere to a coherent and consistent terminology nor always include rigorous interpretations of the processes behind invasion. Therefore, we suggest that a consistent set of definitions and a rigorous conceptual framework are needed. We define invasion in a microbial community as the establishment of an alien microbial type in a resident community and argue how simple criteria to define aliens, residents, and alien establishment can be applied for a wide variety of communities. In addition, we suggest an adoption of the community ecology framework advanced by Vellend (2010) to clarify potential determinants of invasion. This framework identifies four fundamental processes that control community dynamics: dispersal, selection, drift and diversification. While selection has received ample attention in microbial community invasion research, the three other processes are often overlooked. Here, we elaborate on the relevance of all four processes and conclude that invasion experiments should be designed to elucidate the role of dispersal, drift and diversification, in order to obtain a complete picture of invasion as a community process. PMID:27137125

System for monitoring non-coincident, nonstationary process signals

DOEpatents

Gross, Kenneth C.; Wegerich, Stephan W.

2005-01-04

An improved system for monitoring non-coincident, non-stationary, process signals. The mean, variance, and length of a reference signal is defined by an automated system, followed by the identification of the leading and falling edges of a monitored signal and the length of the monitored signal. The monitored signal is compared to the reference signal, and the monitored signal is resampled in accordance with the reference signal. The reference signal is then correlated with the resampled monitored signal such that the reference signal and the resampled monitored signal are coincident in time with each other. The resampled monitored signal is then compared to the reference signal to determine whether the resampled monitored signal is within a set of predesignated operating conditions.

Biologically-based signal processing system applied to noise removal for signal extraction

DOEpatents

Fu, Chi Yung; Petrich, Loren I.

2004-07-13

The method and system described herein use a biologically-based signal processing system for noise removal for signal extraction. A wavelet transform may be used in conjunction with a neural network to imitate a biological system. The neural network may be trained using ideal data derived from physical principles or noiseless signals to determine to remove noise from the signal.

Pervasive randomness in physics: an introduction to its modelling and spectral characterisation

NASA Astrophysics Data System (ADS)

Howard, Roy

2017-10-01

An introduction to the modelling and spectral characterisation of random phenomena is detailed at a level consistent with a first exposure to the subject at an undergraduate level. A signal framework for defining a random process is provided and this underpins an introduction to common random processes including the Poisson point process, the random walk, the random telegraph signal, shot noise, information signalling random processes, jittered pulse trains, birth-death random processes and Markov chains. An introduction to the spectral characterisation of signals and random processes, via either an energy spectral density or a power spectral density, is detailed. The important case of defining a white noise random process concludes the paper.

Selective Heterogeneity in Exoprotease Production by Bacillus subtilis

PubMed Central

Davidson, Fordyce A.; Seon-Yi, Chung; Stanley-Wall, Nicola R.

2012-01-01

Bacteria have elaborate signalling mechanisms to ensure a behavioural response that is most likely to enhance survival in a changing environment. It is becoming increasingly apparent that as part of this response, bacteria are capable of cell differentiation and can generate multiple, mutually exclusive co-existing cell states. These cell states are often associated with multicellular processes that bring benefit to the community as a whole but which may be, paradoxically, disadvantageous to an individual subpopulation. How this process of cell differentiation is controlled is intriguing and remains a largely open question. In this paper, we consider an important aspect of cell differentiation that is known to occur in the Gram-positive bacterium Bacillus subtilis: we investigate the role of two master regulators DegU and Spo0A in the control of extra-cellular protease production. Recent work in this area focussed the on role of DegU in this process and suggested that transient effects in protein production were the drivers of cell-response heterogeneity. Here, using a combination of mathematical modelling, analysis and stochastic simulations, we provide a complementary analysis of this regulatory system that investigates the roles of both DegU and Spo0A in extra-cellular protease production. In doing so, we present a mechanism for bimodality, or system heterogeneity, without the need for a bistable switch in the underlying regulatory network. Moreover, our analysis leads us to conclude that this heterogeneity is in fact a persistent, stable feature. Our results suggest that system response is divided into three zones: low and high signal levels induce a unimodal or undifferentiated response from the cell population with all cells OFF and ON, respectively for exoprotease production. However, for intermediate levels of signal, a heterogeneous response is predicted with a spread of activity levels, representing typical “bet-hedging” behaviour. PMID:22745669

Modeling micro-droplet formation in near-field electrohydrodynamic jet printing

NASA Astrophysics Data System (ADS)

Popell, George Colin

Near-field electrohydrodynamic jet (E-jet) printing has recently gained significant interest within the manufacturing research community because of its ability to produce micro/sub-micron-scale droplets using a wide variety of inks and substrates. However, the process currently operates in open-loop and as a result suffers from unpredictable printing quality. The use of physics-based, control-oriented process models is expected to enable closed-loop control of this printing technique. The objective of this research is to perform a fundamental study of the substrate-side droplet shape-evolution in near-field E-jet printing and to develop a physics-based model of the same that links input parameters such as voltage magnitude and ink properties to the height and diameter of the printed droplet. In order to achieve this objective, a synchronized high-speed imaging and substrate-side current-detection system was used implemented to enable a correlation between the droplet shape parameters and the measured current signal. The experimental data reveals characteristic process signatures and droplet spreading regimes. The results of these studies are then used as the basis for a model that predicts the droplet diameter and height using the measured current signal as the input. A unique scaling factor based on the measured current signal is used in this model instead of relying on empirical scaling laws found in literature. For each of the three inks tested in this study, the average absolute error in the model predictions is under 4.6% for diameter predictions and under 10.6% for height predictions of the steady-state droplet. While printing under non-conducive ambient conditions of low humidity and high temperatures, the use of the environmental correction factor in the model is seen to result in average absolute errors of 10.35% and 12.5% for diameter and height predictions.

Application and Evaluation of Independent Component Analysis Methods to Generalized Seizure Disorder Activities Exhibited in the Brain.

PubMed

George, S Thomas; Balakrishnan, R; Johnson, J Stanly; Jayakumar, J

2017-07-01

EEG records the spontaneous electrical activity of the brain using multiple electrodes placed on the scalp, and it provides a wealth of information related to the functions of brain. Nevertheless, the signals from the electrodes cannot be directly applied to a diagnostic tool like brain mapping as they undergo a "mixing" process because of the volume conduction effect in the scalp. A pervasive problem in neuroscience is determining which regions of the brain are active, given voltage measurements at the scalp. Because of which, there has been a surge of interest among the biosignal processing community to investigate the process of mixing and unmixing to identify the underlying active sources. According to the assumptions of independent component analysis (ICA) algorithms, the resultant mixture obtained from the scalp can be closely approximated by a linear combination of the "actual" EEG signals emanating from the underlying sources of electrical activity in the brain. As a consequence, using these well-known ICA techniques in preprocessing of the EEG signals prior to clinical applications could result in development of diagnostic tool like quantitative EEG which in turn can assist the neurologists to gain noninvasive access to patient-specific cortical activity, which helps in treating neuropathologies like seizure disorders. The popular and proven ICA schemes mentioned in various literature and applications were selected (which includes Infomax, JADE, and SOBI) and applied on generalized seizure disorder samples using EEGLAB toolbox in MATLAB environment to see their usefulness in source separations; and they were validated by the expert neurologist for clinical relevance in terms of pathologies on brain functionalities. The performance of Infomax method was found to be superior when compared with other ICA schemes applied on EEG and it has been established based on the validations carried by expert neurologist for generalized seizure and its clinical correlation. The results are encouraging for furthering the studies in the direction of developing useful brain mapping tools using ICA methods.

Signal Processing in Functional Near-Infrared Spectroscopy (fNIRS): Methodological Differences Lead to Different Statistical Results.

PubMed

Pfeifer, Mischa D; Scholkmann, Felix; Labruyère, Rob

2017-01-01

Even though research in the field of functional near-infrared spectroscopy (fNIRS) has been performed for more than 20 years, consensus on signal processing methods is still lacking. A significant knowledge gap exists between established researchers and those entering the field. One major issue regularly observed in publications from researchers new to the field is the failure to consider possible signal contamination by hemodynamic changes unrelated to neurovascular coupling (i.e., scalp blood flow and systemic blood flow). This might be due to the fact that these researchers use the signal processing methods provided by the manufacturers of their measurement device without an advanced understanding of the performed steps. The aim of the present study was to investigate how different signal processing approaches (including and excluding approaches that partially correct for the possible signal contamination) affect the results of a typical functional neuroimaging study performed with fNIRS. In particular, we evaluated one standard signal processing method provided by a commercial company and compared it to three customized approaches. We thereby investigated the influence of the chosen method on the statistical outcome of a clinical data set (task-evoked motor cortex activity). No short-channels were used in the present study and therefore two types of multi-channel corrections based on multiple long-channels were applied. The choice of the signal processing method had a considerable influence on the outcome of the study. While methods that ignored the contamination of the fNIRS signals by task-evoked physiological noise yielded several significant hemodynamic responses over the whole head, the statistical significance of these findings disappeared when accounting for part of the contamination using a multi-channel regression. We conclude that adopting signal processing methods that correct for physiological confounding effects might yield more realistic results in cases where multi-distance measurements are not possible. Furthermore, we recommend using manufacturers' standard signal processing methods only in case the user has an advanced understanding of every signal processing step performed.

Process dissociation and mixture signal detection theory.

PubMed

DeCarlo, Lawrence T

2008-11-01

The process dissociation procedure was developed in an attempt to separate different processes involved in memory tasks. The procedure naturally lends itself to a formulation within a class of mixture signal detection models. The dual process model is shown to be a special case. The mixture signal detection model is applied to data from a widely analyzed study. The results suggest that a process other than recollection may be involved in the process dissociation procedure.

Programming an offline-analyzer of motor imagery signals via python language.

PubMed

Alonso-Valerdi, Luz María; Sepulveda, Francisco

2011-01-01

Brain Computer Interface (BCI) systems control the user's environment via his/her brain signals. Brain signals related to motor imagery (MI) have become a widespread method employed by the BCI community. Despite the large number of references describing the MI signal treatment, there is not enough information related to the available programming languages that could be suitable to develop a specific-purpose MI-based BCI. The present paper describes the development of an offline-analysis system based on MI-EEG signals via open-source programming languages, and the assessment of the system using electrical activity recorded from three subjects. The analyzer recognized at least 63% of the MI signals corresponding to three classes. The results of the offline analysis showed a promising performance considering that the subjects have never undergone MI trainings.

Community Education: A Community Planning Process Guide.

ERIC Educational Resources Information Center

Wiglesworth, Bill, Comp.

Designed to assist in the planning of community education and services, this booklet offers an argument in support of as well as step-by-step implementation instructions for a 2-day planning process. Following a discussion of the advantages of cooperative planning, the community planning process is outlined. Examined next are the reasons why a…

Development of cardiac prescreening device for rural population using ultralow-power embedded system.

PubMed

Mandal, Subhamoy; Basak, Kausik; Mandana, K M; Ray, Ajoy K; Chatterjee, Jyotirmoy; Mahadevappa, Manjunatha

2011-03-01

The invention is inspired by the desire to understand the opportunities and expectations of developing economies in terms of healthcare. The designed system is a point-of-care (POC) device that can deliver heart-care services to the rural population and bridge the rural-urban divide in healthcare delivery. The product design incorporates several innovations including the effective use of adaptive and multiresolution signal-processing techniques for acquisition, denoising, segmentation, and characterization of the heart sounds (HS) and murmurs using an ultralow-power embedded Mixed Signal Processor. The device is able to provide indicative diagnosis of cardiac conditions and classify a subject into either normal, abnormal, ischemic, or valvular abnormalities category. Preliminary results demonstrated by the prototype confirm the applicability of the device as a prescreening tool that can be used by paramedics in rural outreach programs. Feedback from medical professionals also shows that such a device is helpful in early detection of common congenital heart diseases. This letter aims to determine a framework for utilization of automated HS analysis system for community healthcare and healthcare inclusion.

A Low-cost 4 Bit, 10 Giga-samples-per-second Analog-to-digital Converter Printed Circuit Board Assembly for FPGA-based Backends

NASA Astrophysics Data System (ADS)

Jiang, Homin; Yu, Chen-Yu; Kubo, Derek; Chen, Ming-Tang; Guzzino, Kim

2016-11-01

In this study, a 4 bit, 10 giga-samples-per-second analog-to-digital converter (ADC) printed circuit board assembly (PCBA) was designed, manufactured, and characterized for digitizing radio telescopes. For this purpose, an Adsantec ANST7120A-KMA flash ADC chip was used. Together with the field-programmable gate array platform, developed by the Collaboration for Astronomy Signal Processing and Electronics Research community, the PCBA enables data acquisition with a wide bandwidth and simplifies the intermediate frequency section. In the current version, the PCBA and the chip exhibit an analog bandwidth of 10 GHz (3 dB loss) and 20 GHz, respectively, which facilitates second, third, and even fourth Nyquist sampling. The following average performance parameters were obtained from the first and second Nyquist zones of the three boards: a spurious-free dynamic range of 31.35/30.45 dB, a signal-to-noise and distortion ratio of 22.95/21.83 dB, and an effective number of bits of 3.65/3.43, respectively.

Magnetic resonance spectroscopic imaging at superresolution: Overview and perspectives

NASA Astrophysics Data System (ADS)

Kasten, Jeffrey; Klauser, Antoine; Lazeyras, François; Van De Ville, Dimitri

2016-02-01

The notion of non-invasive, high-resolution spatial mapping of metabolite concentrations has long enticed the medical community. While magnetic resonance spectroscopic imaging (MRSI) is capable of achieving the requisite spatio-spectral localization, it has traditionally been encumbered by significant resolution constraints that have thus far undermined its clinical utility. To surpass these obstacles, research efforts have primarily focused on hardware enhancements or the development of accelerated acquisition strategies to improve the experimental sensitivity per unit time. Concomitantly, a number of innovative reconstruction techniques have emerged as alternatives to the standard inverse discrete Fourier transform (DFT). While perhaps lesser known, these latter methods strive to effect commensurate resolution gains by exploiting known properties of the underlying MRSI signal in concert with advanced image and signal processing techniques. This review article aims to aggregate and provide an overview of the past few decades of so-called "superresolution" MRSI reconstruction methodologies, and to introduce readers to current state-of-the-art approaches. A number of perspectives are then offered as to the future of high-resolution MRSI, with a particular focus on translation into clinical settings.

Fourier Transform Spectrometer System

NASA Technical Reports Server (NTRS)

Campbell, Joel F. (Inventor)

2014-01-01

A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.

Photo-Spectrometer Realized In A Standard Cmos Ic Process

DOEpatents

Simpson, Michael L.; Ericson, M. Nance; Dress, William B.; Jellison, Gerald E.; Sitter, Jr., David N.; Wintenberg, Alan L.

1999-10-12

A spectrometer, comprises: a semiconductor having a silicon substrate, the substrate having integrally formed thereon a plurality of layers forming photo diodes, each of the photo diodes having an independent spectral response to an input spectra within a spectral range of the semiconductor and each of the photo diodes formed only from at least one of the plurality of layers of the semiconductor above the substrate; and, a signal processing circuit for modifying signals from the photo diodes with respective weights, the weighted signals being representative of a specific spectral response. The photo diodes have different junction depths and different polycrystalline silicon and oxide coverings. The signal processing circuit applies the respective weights and sums the weighted signals. In a corresponding method, a spectrometer is manufactured by manipulating only the standard masks, materials and fabrication steps of standard semiconductor processing, and integrating the spectrometer with a signal processing circuit.

New signal processing technique for density profile reconstruction using reflectometry.

PubMed

Clairet, F; Ricaud, B; Briolle, F; Heuraux, S; Bottereau, C

2011-08-01

Reflectometry profile measurement requires an accurate determination of the plasma reflected signal. Along with a good resolution and a high signal to noise ratio of the phase measurement, adequate data analysis is required. A new data processing based on time-frequency tomographic representation is used. It provides a clearer separation between multiple components and improves isolation of the relevant signals. In this paper, this data processing technique is applied to two sets of signals coming from two different reflectometer devices used on the Tore Supra tokamak. For the standard density profile reflectometry, it improves the initialization process and its reliability, providing a more accurate profile determination in the far scrape-off layer with density measurements as low as 10(16) m(-1). For a second reflectometer, which provides measurements in front of a lower hybrid launcher, this method improves the separation of the relevant plasma signal from multi-reflection processes due to the proximity of the plasma.

Electronic filters, repeated signal charge conversion apparatus, hearing aids and methods

NASA Technical Reports Server (NTRS)

Morley, Jr., Robert E. (Inventor); Engebretson, A. Maynard (Inventor); Engel, George L. (Inventor); Sullivan, Thomas J. (Inventor)

1993-01-01

An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed.

Cross Time-Frequency Analysis of Gastrocnemius Electromyographic Signals in Hypertensive and Nonhypertensive Subjects

NASA Astrophysics Data System (ADS)

Mitchell, Patrick; Krotish, Debra; Shin, Yong-June; Hirth, Victor

2010-12-01

The effects of hypertension are chronic and continuous; it affects gait, balance, and fall risk. Therefore, it is desirable to assess gait health across hypertensive and nonhypertensive subjects in order to prevent or reduce the risk of falls. Analysis of electromyography (EMG) signals can identify age related changes of neuromuscular activation due to various neuropathies and myopathies, but it is difficult to translate these medical changes to clinical diagnosis. To examine and compare geriatrics patients with these gait-altering diseases, we acquire EMG muscle activation signals, and by use of a timesynchronized mat capable of recording pressure information, we localize the EMG data to the gait cycle, ensuring identical comparison across subjects. Using time-frequency analysis on the EMG signal, in conjunction with several parameters obtained from the time-frequency analyses, we can determine the statistical discrepancy between diseases. We base these parameters on physiological manifestations caused by hypertension, as well as other comorbities that affect the geriatrics community. Using these metrics in a small population, we identify a statistical discrepancy between a control group and subjects with hypertension, neuropathy, diabetes, osteoporosis, arthritis, and several other common diseases which severely affect the geriatrics community.

Succession of the functional microbial communities and the metabolic functions in maize straw composting process.

PubMed

Wei, Huawei; Wang, Liuhong; Hassan, Muhammad; Xie, Bing

2018-05-01

Illumina MiSeq sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) were applied to study the dynamic changes and effects of microbial community structures as well as the metabolic function of bacterial community in maize straw composting process. Results showed that humic acid contents in loosely combined humus (HA1) and stably combined humus (HA2) increased after composting and Staphylococcus, Cellulosimicrobium and Ochrobactrum possibly participated in the transformation of the process. The bacterial communities differed in different stages of the composting. Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria were reported the dominant phyla throughout the process and the relative abundance of the dominant phyla varied significantly (p < 0.05) over time. Moreover, the total phosphorus (TP) had the greatest influence on the microbial community structure among C/N ratio, available phosphorus (AP) and humic substances. Metabolism, cellular processes and environmental information processing might be the primary functions of microbial community during the composting. Copyright © 2018 Elsevier Ltd. All rights reserved.

Nation Building and Social Signaling in Southern Ontario: A.D. 1350-1650.

PubMed

Hart, John P; Shafie, Termeh; Birch, Jennifer; Dermarkar, Susan; Williamson, Ronald F

2016-01-01

Pottery is a mainstay of archaeological analysis worldwide. Often, high proportions of the pottery recovered from a given site are decorated in some manner. In northern Iroquoia, late pre-contact pottery and early contact decoration commonly occur on collars-thick bands of clay that encircle a pot and extend several centimeters down from the lip. These decorations constitute signals that conveyed information about a pot's user(s). In southern Ontario the period A.D. 1350 to 1650 witnessed substantial changes in socio-political and settlement systems that included population movement, coalescence of formerly separate communities into large villages and towns, waxing and waning of regional strife, the formation of nations, and finally the development of three confederacies that each occupied distinct, constricted areas. Social network analysis demonstrates that signaling practices changed to reflect these regional patterns. Networks become more consolidated through time ultimately resulting in a "small world" network with small degrees of separation between sites reflecting the integration of communities within and between the three confederacies.

Community trees: Identifying codiversification in the Páramo dipteran community.

PubMed

Carstens, Bryan C; Gruenstaeudl, Michael; Reid, Noah M

2016-05-01

Groups of codistributed species that responded in a concerted manner to environmental events are expected to share patterns of evolutionary diversification. However, the identification of such groups has largely been based on qualitative, post hoc analyses. We develop here two methods (posterior predictive simulation [PPS], Kuhner-Felsenstein [K-F] analysis of variance [ANOVA]) for the analysis of codistributed species that, given a group of species with a shared pattern of diversification, allow empiricists to identify those taxa that do not codiversify (i.e., "outlier" species). The identification of outlier species makes it possible to jointly estimate the evolutionary history of co-diversifying taxa. To evaluate the approaches presented here, we collected data from Páramo dipterans, identified outlier species, and estimated a "community tree" from species that are identified as having codiversified. Our results demonstrate that dipteran communities from different Páramo habitats in the same mountain range are more closely related than communities in other ranges. We also conduct simulation testing to evaluate this approach. Results suggest that our approach provides a useful addition to comparative phylogeographic methods, while identifying aspects of the analysis that require careful interpretation. In particular, both the PPS and K-F ANOVA perform acceptably when there are one or two outlier species, but less so as the number of outliers increases. This is likely a function of the corresponding degradation of the signal of community divergence; without a strong signal from a codiversifying community, there is no dominant pattern from which to detect an outlier species. For this reason, both the magnitude of K-F distance distribution and outside knowledge about the phylogeographic history of each putative member of the community should be considered when interpreting the results. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Verrucomicrobial community structure and abundance as indicators for changes in chemical factors linked to soil fertility.

PubMed

Navarrete, Acacio Aparecido; Soares, Tielle; Rossetto, Raffaella; van Veen, Johannes Antonie; Tsai, Siu Mui; Kuramae, Eiko Eurya

2015-09-01

Here we show that verrucomicrobial community structure and abundance are extremely sensitive to changes in chemical factors linked to soil fertility. Terminal restriction fragment length polymorphism fingerprint and real-time quantitative PCR assay were used to analyze changes in verrucomicrobial communities associated with contrasting soil nutrient conditions in tropical regions. In case study Model I ("Slash-and-burn deforestation") the verrucomicrobial community structures revealed disparate patterns in nutrient-enriched soils after slash-and-burn deforestation and natural nutrient-poor soils under an adjacent primary forest in the Amazonia (R = 0.819, P = 0.002). The relative proportion of Verrucomicrobia declined in response to increased soil fertility after slash-and-burn deforestation, accounting on average, for 4 and 2 % of the total bacterial signal, in natural nutrient-poor forest soils and nutrient-enriched deforested soils, respectively. In case study Model II ("Management practices for sugarcane") disparate patterns were revealed in sugarcane rhizosphere sampled on optimal and deficient soil fertility for sugarcane (R = 0.786, P = 0.002). Verrucomicrobial community abundance in sugarcane rhizosphere was negatively correlated with soil fertility, accounting for 2 and 5 % of the total bacterial signal, under optimal and deficient soil fertility conditions for sugarcane, respectively. In nutrient-enriched soils, verrucomicrobial community structures were related to soil factors linked to soil fertility, such as total nitrogen, phosphorus, potassium and sum of bases, i.e., the sum of calcium, magnesium and potassium contents. We conclude that community structure and abundance represent important ecological aspects in soil verrucomicrobial communities for tracking the changes in chemical factors linked to soil fertility under tropical environmental conditions.

Trust the process: community health psychology after Occupy.

PubMed

Cornish, Flora; Montenegro, Cristian; van Reisen, Kirsten; Zaka, Flavia; Sevitt, James

2014-01-01

This article argues that community health psychology's core strategy of 'community mobilisation' is in need of renewal and proposes a new way of conceptualising community health action. Taking the Occupy movement as an example, we critique modernist understandings of community mobilisation, which are based on instrumental action in the service of a predetermined goal. Aiming to re-invigorate the 'process' tradition of community health psychology, we explore possibilities of an open-ended, anti-hierarchical and inclusive mode of community action, which we label 'trusting the process'. The gains to be made are unpredictable, but we suggest that the risk is worth taking.

Patterns and Processes of Microbial Community Assembly

PubMed Central

Schmidt, Steven K.; Fukami, Tadashi; O'Neill, Sean P.; Bilinski, Teresa M.; Stanish, Lee F.; Knelman, Joseph E.; Darcy, John L.; Lynch, Ryan C.; Wickey, Phillip; Ferrenberg, Scott

2013-01-01

SUMMARY Recent research has expanded our understanding of microbial community assembly. However, the field of community ecology is inaccessible to many microbial ecologists because of inconsistent and often confusing terminology as well as unnecessarily polarizing debates. Thus, we review recent literature on microbial community assembly, using the framework of Vellend (Q. Rev. Biol. 85:183–206, 2010) in an effort to synthesize and unify these contributions. We begin by discussing patterns in microbial biogeography and then describe four basic processes (diversification, dispersal, selection, and drift) that contribute to community assembly. We also discuss different combinations of these processes and where and when they may be most important for shaping microbial communities. The spatial and temporal scales of microbial community assembly are also discussed in relation to assembly processes. Throughout this review paper, we highlight differences between microbes and macroorganisms and generate hypotheses describing how these differences may be important for community assembly. We end by discussing the implications of microbial assembly processes for ecosystem function and biodiversity. PMID:24006468

Standardized processing of MALDI imaging raw data for enhancement of weak analyte signals in mouse models of gastric cancer and Alzheimer's disease.

PubMed

Schwartz, Matthias; Meyer, Björn; Wirnitzer, Bernhard; Hopf, Carsten

2015-03-01

Conventional mass spectrometry image preprocessing methods used for denoising, such as the Savitzky-Golay smoothing or discrete wavelet transformation, typically do not only remove noise but also weak signals. Recently, memory-efficient principal component analysis (PCA) in conjunction with random projections (RP) has been proposed for reversible compression and analysis of large mass spectrometry imaging datasets. It considers single-pixel spectra in their local context and consequently offers the prospect of using information from the spectra of adjacent pixels for denoising or signal enhancement. However, little systematic analysis of key RP-PCA parameters has been reported so far, and the utility and validity of this method for context-dependent enhancement of known medically or pharmacologically relevant weak analyte signals in linear-mode matrix-assisted laser desorption/ionization (MALDI) mass spectra has not been explored yet. Here, we investigate MALDI imaging datasets from mouse models of Alzheimer's disease and gastric cancer to systematically assess the importance of selecting the right number of random projections k and of principal components (PCs) L for reconstructing reproducibly denoised images after compression. We provide detailed quantitative data for comparison of RP-PCA-denoising with the Savitzky-Golay and wavelet-based denoising in these mouse models as a resource for the mass spectrometry imaging community. Most importantly, we demonstrate that RP-PCA preprocessing can enhance signals of low-intensity amyloid-β peptide isoforms such as Aβ1-26 even in sparsely distributed Alzheimer's β-amyloid plaques and that it enables enhanced imaging of multiply acetylated histone H4 isoforms in response to pharmacological histone deacetylase inhibition in vivo. We conclude that RP-PCA denoising may be a useful preprocessing step in biomarker discovery workflows.

Controlled membrane translocation provides a mechanism for signal transduction and amplification

NASA Astrophysics Data System (ADS)

Langton, Matthew J.; Keymeulen, Flore; Ciaccia, Maria; Williams, Nicholas H.; Hunter, Christopher A.

2017-05-01

Transmission and amplification of chemical signals across lipid bilayer membranes is of profound significance in many biological processes, from the development of multicellular organisms to information processing in the nervous system. In biology, membrane-spanning proteins are responsible for the transmission of chemical signals across membranes, and signal transduction is often associated with an amplified signalling cascade. The ability to reproduce such processes in artificial systems has potential applications in sensing, controlled drug delivery and communication between compartments in tissue-like constructs of synthetic vesicles. Here we describe a mechanism for transmitting a chemical signal across a membrane based on the controlled translocation of a synthetic molecular transducer from one side of a lipid bilayer membrane to the other. The controlled molecular motion has been coupled to the activation of a catalyst on the inside of a vesicle, which leads to a signal-amplification process analogous to the biological counterpart.

Introduction to Radar Signal and Data Processing: The Opportunity

DTIC Science & Technology

2006-09-01

SpA) Director of Analysis of Integrated Systems Group Via Tiburtina Km. 12.400 00131 Rome ITALY e.mail: afarina@selex-si.com Key words: radar...signal processing, data processing, adaptivity, space-time adaptive processing, knowledge based systems , CFAR. 1. SUMMARY This paper introduces to...the lecture series dedicated to the knowledge-based radar signal and data processing. Knowledge-based expert system (KBS) is in the realm of

Standards for data acquisition and software-based analysis of in vivo electroencephalography recordings from animals. A TASK1-WG5 report of the AES/ILAE Translational Task Force of the ILAE.

PubMed

Moyer, Jason T; Gnatkovsky, Vadym; Ono, Tomonori; Otáhal, Jakub; Wagenaar, Joost; Stacey, William C; Noebels, Jeffrey; Ikeda, Akio; Staley, Kevin; de Curtis, Marco; Litt, Brian; Galanopoulou, Aristea S

2017-11-01

Electroencephalography (EEG)-the direct recording of the electrical activity of populations of neurons-is a tremendously important tool for diagnosing, treating, and researching epilepsy. Although standard procedures for recording and analyzing human EEG exist and are broadly accepted, there are no such standards for research in animal models of seizures and epilepsy-recording montages, acquisition systems, and processing algorithms may differ substantially among investigators and laboratories. The lack of standard procedures for acquiring and analyzing EEG from animal models of epilepsy hinders the interpretation of experimental results and reduces the ability of the scientific community to efficiently translate new experimental findings into clinical practice. Accordingly, the intention of this report is twofold: (1) to review current techniques for the collection and software-based analysis of neural field recordings in animal models of epilepsy, and (2) to offer pertinent standards and reporting guidelines for this research. Specifically, we review current techniques for signal acquisition, signal conditioning, signal processing, data storage, and data sharing, and include applicable recommendations to standardize collection and reporting. We close with a discussion of challenges and future opportunities, and include a supplemental report of currently available acquisition systems and analysis tools. This work represents a collaboration on behalf of the American Epilepsy Society/International League Against Epilepsy (AES/ILAE) Translational Task Force (TASK1-Workgroup 5), and is part of a larger effort to harmonize video-EEG interpretation and analysis methods across studies using in vivo and in vitro seizure and epilepsy models. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Development Of A Three-Dimensional Circuit Integration Technology And Computer Architecture

NASA Astrophysics Data System (ADS)

Etchells, R. D.; Grinberg, J.; Nudd, G. R.

1981-12-01

This paper is the first of a series 1,2,3 describing a range of efforts at Hughes Research Laboratories, which are collectively referred to as "Three-Dimensional Microelectronics." The technology being developed is a combination of a unique circuit fabrication/packaging technology and a novel processing architecture. The packaging technology greatly reduces the parasitic impedances associated with signal-routing in complex VLSI structures, while simultaneously allowing circuit densities orders of magnitude higher than the current state-of-the-art. When combined with the 3-D processor architecture, the resulting machine exhibits a one- to two-order of magnitude simultaneous improvement over current state-of-the-art machines in the three areas of processing speed, power consumption, and physical volume. The 3-D architecture is essentially that commonly referred to as a "cellular array", with the ultimate implementation having as many as 512 x 512 processors working in parallel. The three-dimensional nature of the assembled machine arises from the fact that the chips containing the active circuitry of the processor are stacked on top of each other. In this structure, electrical signals are passed vertically through the chips via thermomigrated aluminum feedthroughs. Signals are passed between adjacent chips by micro-interconnects. This discussion presents a broad view of the total effort, as well as a more detailed treatment of the fabrication and packaging technologies themselves. The results of performance simulations of the completed 3-D processor executing a variety of algorithms are also presented. Of particular pertinence to the interests of the focal-plane array community is the simulation of the UNICORNS nonuniformity correction algorithms as executed by the 3-D architecture.

Ice thickness measurements over Pine Island and Thwaites Glaciers

NASA Astrophysics Data System (ADS)

Kanagaratnam, P.; Casassa, G.; Thomas, R.; Gogineni, S.

2003-04-01

The Pine Island and Thwaites glaciers (PIG and TG) are the fastest measured glaciers in Antarctica and have been identified as the part of the West Antarctica ice sheet most prone to instability. However, the reasons for the rapid retreat of these glaciers have not been resolved due to insufficient data. In particular, the role of ice shelves in regulating the ice discharge of these glaciers has been a point of contention in the glaciology community. To help resolve this issue the Centro de Estudios Científicos (CECS) and NASA with the support of the Armada de Chile conducted four airborne remote sensing missions over the PIG/TG regions. In addition, two missions were conducted over the Antarctic Peninsula. The University of Kansas operated its Coherent Radar Depth Sounder (CORDS) to measure the thickness of the ice sheet in these regions. CORDS is a pulse-compression radar that has proven its utility in the glaciological surveys over Greenland. The combination of pulse compression and coherent processing has allowed us to obtain high-sensitivity and high-resolution in the along-track direction while keeping the transmitted power low. CORDS transmits a 140-160 MHz chirp signal with 200 Watts of peak power and has a vertical resolution of about 5 meters in ice. We used a four-element dipole array on either side of the wing to transmit and receive the radar signals. We successfully mapped the thickness of the ice sheet over 99% of the PIG/TG flight lines. In this paper we will provide a description of the radar, experiment and signal processing. We will also discuss samples results of the ice thickness, basal conditions and surface roughness.

Social media and disasters: a functional framework for social media use in disaster planning, response, and research.

PubMed

Houston, J Brian; Hawthorne, Joshua; Perreault, Mildred F; Park, Eun Hae; Goldstein Hode, Marlo; Halliwell, Michael R; Turner McGowen, Sarah E; Davis, Rachel; Vaid, Shivani; McElderry, Jonathan A; Griffith, Stanford A

2015-01-01

A comprehensive review of online, official, and scientific literature was carried out in 2012-13 to develop a framework of disaster social media. This framework can be used to facilitate the creation of disaster social media tools, the formulation of disaster social media implementation processes, and the scientific study of disaster social media effects. Disaster social media users in the framework include communities, government, individuals, organisations, and media outlets. Fifteen distinct disaster social media uses were identified, ranging from preparing and receiving disaster preparedness information and warnings and signalling and detecting disasters prior to an event to (re)connecting community members following a disaster. The framework illustrates that a variety of entities may utilise and produce disaster social media content. Consequently, disaster social media use can be conceptualised as occurring at a number of levels, even within the same disaster. Suggestions are provided on how the proposed framework can inform future disaster social media development and research. © 2014 2014 The Author(s). Disasters © Overseas Development Institute, 2014.

Experimental demonstration of a format-flexible single-carrier coherent receiver using data-aided digital signal processing.

PubMed

Elschner, Robert; Frey, Felix; Meuer, Christian; Fischer, Johannes Karl; Alreesh, Saleem; Schmidt-Langhorst, Carsten; Molle, Lutz; Tanimura, Takahito; Schubert, Colja

2012-12-17

We experimentally demonstrate the use of data-aided digital signal processing for format-flexible coherent reception of different 28-GBd PDM and 4D modulated signals in WDM transmission experiments over up to 7680 km SSMF by using the same resource-efficient digital signal processing algorithms for the equalization of all formats. Stable and regular performance in the nonlinear transmission regime is confirmed.

Signal Processing and Interpretation Using Multilevel Signal Abstractions.

DTIC Science & Technology

1986-06-01

mappings expressed in the Fourier domain. Pre- viously proposed causal analysis techniques for diagnosis are based on the analysis of intermediate data ...can be processed either as individual one-dimensional waveforms or as multichannel data 26 I P- - . . . ." " ." h9. for source detection and direction...microphone data . The signal processing for both spectral analysis of microphone signals and direc- * tion determination of acoustic sources involves

Acoustic emission signal processing technique to characterize reactor in-pile phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agarwal, Vivek, E-mail: vivek.agarwal@inl.gov; Tawfik, Magdy S., E-mail: magdy.tawfik@inl.gov; Smith, James A., E-mail: james.smith@inl.gov

2015-03-31

Existing and developing advanced sensor technologies and instrumentation will allow non-intrusive in-pile measurement of temperature, extension, and fission gases when coupled with advanced signal processing algorithms. The transmitted measured sensor signals from inside to the outside of containment structure are corrupted by noise and are attenuated, thereby reducing the signal strength and the signal-to-noise ratio. Identification and extraction of actual signal (representative of an in-pile phenomenon) is a challenging and complicated process. In the paper, empirical mode decomposition technique is utilized to reconstruct actual sensor signal by partially combining intrinsic mode functions. Reconstructed signal will correspond to phenomena and/or failuremore » modes occurring inside the reactor. In addition, it allows accurate non-intrusive monitoring and trending of in-pile phenomena.« less

Identifying high frequency signals in the daily swath mascon solutions from GRACE

NASA Astrophysics Data System (ADS)

Save, H.

2016-12-01

The Gravity Recovery and Climate Experiment (GRACE) mission has provided us with unique information about the total water column in the Earth system over the past 14 years. The GRACE project provides a monthly mean time-variable gravity solution. There has been significant progress in the community over the years to develop shorter time-window gravity solutions. The daily swath mascon solutions, which are under development at the Center for Space Research (CSR), are computed using daily GRACE observation data. This paper discusses the development and the progress of this product. This paper summarizes the analysis of these solutions with special emphasis on identifying the higher frequency natural processes observed by GRACE using these daily swath mascon solutions.

Mass Movement Susceptibility Mapping Using Satellite Optical Imagery Compared With INSAR Monitoring: Zigui County, Three Gorges Region, China

NASA Astrophysics Data System (ADS)

Kincal, Cem; Singleton, Andrew; Liu, Peng; Li, Zhenhong; Drummond, Jane; Hoey, Trevor; Muller, Jan-Peter; Qu, Wei; Zeng, Qiming; Zhang, Jingfa; Du, Peijun

2010-10-01

Mass movements on steep slopes are a major hazard to communities and infrastructure in the Three Gorges region, China. Developing susceptibility maps of mass movements is therefore very important in both current and future land use planning. This study employed satellite optical imagery and an ASTER GDEM (15 m) to derive various parameters (namely geology; slope gradient; proximity to drainage networks and proximity to lineaments) in order to create a GIS-based map of mass movement susceptibility. This map was then evaluated using highly accurate deformation signals processed using the Persistent Scatterer (PS) InSAR technique. Areas of high susceptibility correspond well to points of high subsidence, which provides a strong support of our susceptibility map.

A compact light-sheet microscope for the study of the mammalian central nervous system

PubMed Central

Yang, Zhengyi; Haslehurst, Peter; Scott, Suzanne; Emptage, Nigel; Dholakia, Kishan

2016-01-01

Investigation of the transient processes integral to neuronal function demands rapid and high-resolution imaging techniques over a large field of view, which cannot be achieved with conventional scanning microscopes. Here we describe a compact light sheet fluorescence microscope, featuring a 45° inverted geometry and an integrated photolysis laser, that is optimized for applications in neuroscience, in particular fast imaging of sub-neuronal structures in mammalian brain slices. We demonstrate the utility of this design for three-dimensional morphological reconstruction, activation of a single synapse with localized photolysis, and fast imaging of neuronal Ca2+ signalling across a large field of view. The developed system opens up a host of novel applications for the neuroscience community. PMID:27215692

Low-pass parabolic FFT filter for airborne and satellite lidar signal processing.

PubMed

Jiao, Zhongke; Liu, Bo; Liu, Enhai; Yue, Yongjian

2015-10-14

In order to reduce random errors of the lidar signal inversion, a low-pass parabolic fast Fourier transform filter (PFFTF) was introduced for noise elimination. A compact airborne Raman lidar system was studied, which applied PFFTF to process lidar signals. Mathematics and simulations of PFFTF along with low pass filters, sliding mean filter (SMF), median filter (MF), empirical mode decomposition (EMD) and wavelet transform (WT) were studied, and the practical engineering value of PFFTF for lidar signal processing has been verified. The method has been tested on real lidar signal from Wyoming Cloud Lidar (WCL). Results show that PFFTF has advantages over the other methods. It keeps the high frequency components well and reduces much of the random noise simultaneously for lidar signal processing.

Field programmable gate array processing of eye-safe all-fiber coherent wind Doppler lidar return signals

NASA Astrophysics Data System (ADS)

Abdelazim, S.; Santoro, D.; Arend, M.; Moshary, F.; Ahmed, S.

2011-11-01

A field deployable all-fiber eye-safe Coherent Doppler LIDAR is being developed at the Optical Remote Sensing Lab at the City College of New York (CCNY) and is designed to monitor wind fields autonomously and continuously in urban settings. Data acquisition is accomplished by sampling lidar return signals at 400 MHz and performing onboard processing using field programmable gate arrays (FPGAs). The FPGA is programmed to accumulate signal information that is used to calculate the power spectrum of the atmospherically back scattered signal. The advantage of using FPGA is that signal processing will be performed at the hardware level, reducing the load on the host computer and allowing for 100% return signal processing. An experimental setup measured wind speeds at ranges of up to 3 km.

Microbial community redundancy in anaerobic digestion drives process recovery after salinity exposure.

PubMed

De Vrieze, Jo; Christiaens, Marlies E R; Walraedt, Diego; Devooght, Arno; Ijaz, Umer Zeeshan; Boon, Nico

2017-03-15

Anaerobic digestion of high-salinity wastewaters often results in process inhibition due to the susceptibility of the methanogenic archaea. The ability of the microbial community to deal with increased salinity levels is of high importance to ensure process perseverance or recovery after failure. The exact strategy of the microbial community to ensure process endurance is, however, often unknown. In this study, we investigated how the microbial community is able to recover process performance following a disturbance through the application of high-salinity molasses wastewater. After a stable start-up, methane production quickly decreased from 625 ± 17 to 232 ± 35 mL CH 4 L -1 d -1 with a simultaneous accumulation in volatile fatty acids up to 20.5 ± 1.4 g COD L -1 , indicating severe process disturbance. A shift in feedstock from molasses wastewater to waste activated sludge resulted in complete process recovery. However, the bacterial and archaeal communities did not return to their original composition as before the disturbance, despite similar process conditions. Microbial community diversity was recovered to similar levels as before disturbance, which indicates that the metabolic potential of the community was maintained. A mild increase in ammonia concentration after process recovery did not influence methane production, indicating a well-balanced microbial community. Hence, given the change in community composition following recovery after salinity disturbance, it can be assumed that microbial community redundancy was the major strategy to ensure the continuation of methane production, without loss of functionality or metabolic flexibility. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Should I stay or should I go? Initiation of joint travel in mother-infant dyads of two chimpanzee communities in the wild.

PubMed

Fröhlich, Marlen; Wittig, Roman M; Pika, Simone

2016-05-01

It is well established that great apes communicate via intentionally produced, elaborate and flexible gestural means. Yet relatively little is known about the most fundamental steps into this communicative endeavour-communicative exchanges of mother-infant dyads and gestural acquisition; perhaps because the majority of studies concerned captive groups and single communities in the wild only. Here, we report the first systematic, quantitative comparison of communicative interactions of mother-infant dyads in two communities of wild chimpanzees by focusing on a single communicative function: initiation of carries for joint travel. Over 156 days of observation, we recorded 442 actions, 599 cases of intentional gesture production, 51 multi-modal combinations and 80 vocalisations in the Kanyawara community, Kibale National Park, Uganda, and the Taï South community, Taï National Park, Côte d'Ivoire. Our results showed that (1) mothers and infants differed concerning the signal frequency and modality employed to initiate joint travel, (2) concordance rates of mothers' gestural production were relatively low within but also between communities, (3) infant communicative development is characterised by a shift from mainly vocal to gestural means, and (4) chimpanzee mothers adjusted their signals to the communicative level of their infants. Since neither genetic channelling nor ontogenetic ritualization explains our results satisfactorily, we propose a revised theory of gestural acquisition, social negotiation, in which gestures are the output of social shaping, shared understanding and mutual construction in real time by both interactants.

Development of microcontroller-based acquisition and processing unit for fiber optic vibration sensor

NASA Astrophysics Data System (ADS)

Suryadi; Puranto, P.; Adinanta, H.; Waluyo, T. B.; Priambodo, P. S.

2017-04-01

Microcontroller based acquisition and processing unit (MAPU) has been developed to measure vibration signal from fiber optic vibration sensor. The MAPU utilizes a 32-bit ARM microcontroller to perform acquisition and processing of the input signal. The input signal is acquired with 12 bit ADC and processed using FFT method to extract frequency information. Stability of MAPU is characterized by supplying a constant input signal at 500 Hz for 29 hours and shows a stable operation. To characterize the frequency response, input signal is swapped from 20 to 1000 Hz with 20 Hz interval. The characterization result shows that MAPU can detect input signal from 20 to 1000 Hz with minimum signal of 4 mV RMS. The experiment has been set that utilizes the MAPU with singlemode-multimode-singlemode (SMS) fiber optic sensor to detect vibration which is induced by a transducer in a wooden platform. The experimental result indicates that vibration signal from 20 to 600 Hz has been successfully detected. Due to the limitation of the vibration source used in the experiment, vibration signal above 600 Hz is undetected.

From individuals to populations to communities: a dynamic energy budget model of marine ecosystem size-spectrum including life history diversity.

PubMed

Maury, Olivier; Poggiale, Jean-Christophe

2013-05-07

Individual metabolism, predator-prey relationships, and the role of biodiversity are major factors underlying the dynamics of food webs and their response to environmental variability. Despite their crucial, complementary and interacting influences, they are usually not considered simultaneously in current marine ecosystem models. In an attempt to fill this gap and determine if these factors and their interaction are sufficient to allow realistic community structure and dynamics to emerge, we formulate a mathematical model of the size-structured dynamics of marine communities which integrates mechanistically individual, population and community levels. The model represents the transfer of energy generated in both time and size by an infinite number of interacting fish species spanning from very small to very large species. It is based on standard individual level assumptions of the Dynamic Energy Budget theory (DEB) as well as important ecological processes such as opportunistic size-based predation and competition for food. Resting on the inter-specific body-size scaling relationships of the DEB theory, the diversity of life-history traits (i.e. biodiversity) is explicitly integrated. The stationary solutions of the model as well as the transient solutions arising when environmental signals (e.g. variability of primary production and temperature) propagate through the ecosystem are studied using numerical simulations. It is shown that in the absence of density-dependent feedback processes, the model exhibits unstable oscillations. Density-dependent schooling probability and schooling-dependent predatory and disease mortalities are proposed to be important stabilizing factors allowing stationary solutions to be reached. At the community level, the shape and slope of the obtained quasi-linear stationary spectrum matches well with empirical studies. When oscillations of primary production are simulated, the model predicts that the variability propagates along the spectrum in a given frequency-dependent size range before decreasing for larger sizes. At the species level, the simulations show that small and large species dominate the community successively (small species being more abundant at small sizes and large species being more abundant at large sizes) and that the total biomass of a species decreases with its maximal size which again corroborates empirical studies. Our results indicate that the simultaneous consideration of individual growth and reproduction, size-structured trophic interactions, the diversity of life-history traits and a density-dependent stabilizing process allow realistic community structure and dynamics to emerge without any arbitrary prescription. As a logical consequence of our model construction and a basis for future studies, we define the function Φ as the relative contribution of each species to the total biomass of the ecosystem, for any given size. We argue that this function is a measure of the functional role of biodiversity characterizing the impact of the structure of the community (its species composition) on its function (the relative proportions of losses, dissipation and biological work). Copyright © 2013 Elsevier Ltd. All rights reserved.

Introducing Multisensor Satellite Radiance-Based Evaluation for Regional Earth System Modeling

NASA Technical Reports Server (NTRS)

Matsui, T.; Santanello, J.; Shi, J. J.; Tao, W.-K.; Wu, D.; Peters-Lidard, C.; Kemp, E.; Chin, M.; Starr, D.; Sekiguchi, M.;

The comparative ecology and biogeography of parasites

PubMed Central

Poulin, Robert; Krasnov, Boris R.; Mouillot, David; Thieltges, David W.

2011-01-01

Comparative ecology uses interspecific relationships among traits, while accounting for the phylogenetic non-independence of species, to uncover general evolutionary processes. Applied to biogeographic questions, it can be a powerful tool to explain the spatial distribution of organisms. Here, we review how comparative methods can elucidate biogeographic patterns and processes, using analyses of distributional data on parasites (fleas and helminths) as case studies. Methods exist to detect phylogenetic signals, i.e. the degree of phylogenetic dependence of a given character, and either to control for these signals in statistical analyses of interspecific data, or to measure their contribution to variance. Parasite–host interactions present a special case, as a given trait may be a parasite trait, a host trait or a property of the coevolved association rather than of one participant only. For some analyses, it is therefore necessary to correct simultaneously for both parasite phylogeny and host phylogeny, or to evaluate which has the greatest influence on trait expression. Using comparative approaches, we show that two fundamental properties of parasites, their niche breadth, i.e. host specificity, and the nature of their life cycle, can explain interspecific and latitudinal variation in the sizes of their geographical ranges, or rates of distance decay in the similarity of parasite communities. These findings illustrate the ways in which phylogenetically based comparative methods can contribute to biogeographic research. PMID:21768153

Correlating the electrification of volcanic plumes with ashfall textures at Sakurajima Volcano, Japan

NASA Astrophysics Data System (ADS)

Smith, Cassandra M.; Van Eaton, Alexa R.; Charbonnier, Sylvain; McNutt, Stephen R.; Behnke, Sonja A.; Thomas, Ronald J.; Edens, Harald E.; Thompson, Glenn

2018-06-01

Volcanic lightning detection has become a useful resource for monitoring remote, under-instrumented volcanoes. Previous studies have shown that the behavior of volcanic plume electrification responds to changes in the eruptive processes and products. However, there has not yet been a study to quantify the links between ash textures and plume electrification during an actively monitored eruption. In this study, we examine a sequence of vulcanian eruptions from Sakurajima Volcano in Japan to compare ash textural properties (grain size, shape, componentry, and groundmass crystallinity) to plume electrification using a lightning mapping array and other monitoring data. We show that the presence of the continual radio frequency (CRF) signal is more likely to occur during eruptions that produce large seismic amplitudes (>7 μm) and glass-rich volcanic ash with more equant particle shapes. We show that CRF is generated during energetic, impulsive eruptions, where charge buildup is enhanced by secondary fragmentation (milling) as particles travel out of the conduit and into the gas-thrust region of the plume. We show that the CRF signal is influenced by a different electrification process than later volcanic lightning. By using volcanic CRF and lightning to better understand the eruptive event and its products these key observations will help the monitoring community better utilize volcanic electrification as a method for monitoring and understanding ongoing explosive eruptions.

pySPACE—a signal processing and classification environment in Python

PubMed Central

Krell, Mario M.; Straube, Sirko; Seeland, Anett; Wöhrle, Hendrik; Teiwes, Johannes; Metzen, Jan H.; Kirchner, Elsa A.; Kirchner, Frank

2013-01-01

In neuroscience large amounts of data are recorded to provide insights into cerebral information processing and function. The successful extraction of the relevant signals becomes more and more challenging due to increasing complexities in acquisition techniques and questions addressed. Here, automated signal processing and machine learning tools can help to process the data, e.g., to separate signal and noise. With the presented software pySPACE (http://pyspace.github.io/pyspace), signal processing algorithms can be compared and applied automatically on time series data, either with the aim of finding a suitable preprocessing, or of training supervised algorithms to classify the data. pySPACE originally has been built to process multi-sensor windowed time series data, like event-related potentials from the electroencephalogram (EEG). The software provides automated data handling, distributed processing, modular build-up of signal processing chains and tools for visualization and performance evaluation. Included in the software are various algorithms like temporal and spatial filters, feature generation and selection, classification algorithms, and evaluation schemes. Further, interfaces to other signal processing tools are provided and, since pySPACE is a modular framework, it can be extended with new algorithms according to individual needs. In the presented work, the structural hierarchies are described. It is illustrated how users and developers can interface the software and execute offline and online modes. Configuration of pySPACE is realized with the YAML format, so that programming skills are not mandatory for usage. The concept of pySPACE is to have one comprehensive tool that can be used to perform complete signal processing and classification tasks. It further allows to define own algorithms, or to integrate and use already existing libraries. PMID:24399965

pySPACE-a signal processing and classification environment in Python.

PubMed

Krell, Mario M; Straube, Sirko; Seeland, Anett; Wöhrle, Hendrik; Teiwes, Johannes; Metzen, Jan H; Kirchner, Elsa A; Kirchner, Frank

2013-01-01

In neuroscience large amounts of data are recorded to provide insights into cerebral information processing and function. The successful extraction of the relevant signals becomes more and more challenging due to increasing complexities in acquisition techniques and questions addressed. Here, automated signal processing and machine learning tools can help to process the data, e.g., to separate signal and noise. With the presented software pySPACE (http://pyspace.github.io/pyspace), signal processing algorithms can be compared and applied automatically on time series data, either with the aim of finding a suitable preprocessing, or of training supervised algorithms to classify the data. pySPACE originally has been built to process multi-sensor windowed time series data, like event-related potentials from the electroencephalogram (EEG). The software provides automated data handling, distributed processing, modular build-up of signal processing chains and tools for visualization and performance evaluation. Included in the software are various algorithms like temporal and spatial filters, feature generation and selection, classification algorithms, and evaluation schemes. Further, interfaces to other signal processing tools are provided and, since pySPACE is a modular framework, it can be extended with new algorithms according to individual needs. In the presented work, the structural hierarchies are described. It is illustrated how users and developers can interface the software and execute offline and online modes. Configuration of pySPACE is realized with the YAML format, so that programming skills are not mandatory for usage. The concept of pySPACE is to have one comprehensive tool that can be used to perform complete signal processing and classification tasks. It further allows to define own algorithms, or to integrate and use already existing libraries.

A miniature electronic nose system based on an MWNT-polymer microsensor array and a low-power signal-processing chip.

PubMed

Chiu, Shih-Wen; Wu, Hsiang-Chiu; Chou, Ting-I; Chen, Hsin; Tang, Kea-Tiong

2014-06-01

This article introduces a power-efficient, miniature electronic nose (e-nose) system. The e-nose system primarily comprises two self-developed chips, a multiple-walled carbon nanotube (MWNT)-polymer based microsensor array, and a low-power signal-processing chip. The microsensor array was fabricated on a silicon wafer by using standard photolithography technology. The microsensor array comprised eight interdigitated electrodes surrounded by SU-8 "walls," which restrained the material-solvent liquid in a defined area of 650 × 760 μm(2). To achieve a reliable sensor-manufacturing process, we used a two-layer deposition method, coating the MWNTs and polymer film as the first and second layers, respectively. The low-power signal-processing chip included array data acquisition circuits and a signal-processing core. The MWNT-polymer microsensor array can directly connect with array data acquisition circuits, which comprise sensor interface circuitry and an analog-to-digital converter; the signal-processing core consists of memory and a microprocessor. The core executes the program, classifying the odor data received from the array data acquisition circuits. The low-power signal-processing chip was designed and fabricated using the Taiwan Semiconductor Manufacturing Company 0.18-μm 1P6M standard complementary metal oxide semiconductor process. The chip consumes only 1.05 mW of power at supply voltages of 1 and 1.8 V for the array data acquisition circuits and the signal-processing core, respectively. The miniature e-nose system, which used a microsensor array, a low-power signal-processing chip, and an embedded k-nearest-neighbor-based pattern recognition algorithm, was developed as a prototype that successfully recognized the complex odors of tincture, sorghum wine, sake, whisky, and vodka.

Signal processing methods for MFE plasma diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candy, J.V.; Casper, T.; Kane, R.

1985-02-01

The application of various signal processing methods to extract energy storage information from plasma diamagnetism sensors occurring during physics experiments on the Tandom Mirror Experiment-Upgrade (TMX-U) is discussed. We show how these processing techniques can be used to decrease the uncertainty in the corresponding sensor measurements. The algorithms suggested are implemented using SIG, an interactive signal processing package developed at LLNL.

Epidemic spreading on complex networks with community structures

PubMed Central

Stegehuis, Clara; van der Hofstad, Remco; van Leeuwaarden, Johan S. H.

2016-01-01

Many real-world networks display a community structure. We study two random graph models that create a network with similar community structure as a given network. One model preserves the exact community structure of the original network, while the other model only preserves the set of communities and the vertex degrees. These models show that community structure is an important determinant of the behavior of percolation processes on networks, such as information diffusion or virus spreading: the community structure can both enforce as well as inhibit diffusion processes. Our models further show that it is the mesoscopic set of communities that matters. The exact internal structures of communities barely influence the behavior of percolation processes across networks. This insensitivity is likely due to the relative denseness of the communities. PMID:27440176

Real-time holographic surveillance system

DOEpatents

Collins, H.D.; McMakin, D.L.; Hall, T.E.; Gribble, R.P.

1995-10-03

A holographic surveillance system is disclosed including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm. 21 figs.

Signal processing of bedload transport impact amplitudes on accelerometer instrumented plates

USDA-ARS?s Scientific Manuscript database

This work was performed to help establish a data processing methodology for relating accelerometer signals caused by impacts of gravel on steel plates to the mass and size of the transported material. Signal processing was performed on impact plate data collected in flume experiments at the Nationa...

Asymmetric Dual-Band Tracking Technique for Optimal Joint Processing of BDS B1I and B1C Signals

PubMed Central

Wang, Chuhan; Cui, Xiaowei; Ma, Tianyi; Lu, Mingquan

2017-01-01

Along with the rapid development of the Global Navigation Satellite System (GNSS), satellite navigation signals have become more diversified, complex, and agile in adapting to increasing market demands. Various techniques have been developed for processing multiple navigation signals to achieve better performance in terms of accuracy, sensitivity, and robustness. This paper focuses on a technique for processing two signals with separate but adjacent center frequencies, such as B1I and B1C signals in the BeiDou global system. The two signals may differ in modulation scheme, power, and initial phase relation and can be processed independently by user receivers; however, the propagation delays of the two signals from a satellite are nearly identical as they are modulated on adjacent frequencies, share the same reference clock, and undergo nearly identical propagation paths to the receiver, resulting in strong coherence between the two signals. Joint processing of these signals can achieve optimal measurement performance due to the increased Gabor bandwidth and power. In this paper, we propose a universal scheme of asymmetric dual-band tracking (ASYM-DBT) to take advantage of the strong coherence, the increased Gabor bandwidth, and power of the two signals in achieving much-reduced thermal noise and more accurate ranging results when compared with the traditional single-band algorithm. PMID:29035350

Laser pulse coded signal frequency measuring device based on DSP and CPLD

NASA Astrophysics Data System (ADS)

Zhang, Hai-bo; Cao, Li-hua; Geng, Ai-hui; Li, Yan; Guo, Ru-hai; Wang, Ting-feng

2011-06-01

Laser pulse code is an anti-jamming measures used in semi-active laser guided weapons. On account of the laser-guided signals adopting pulse coding mode and the weak signal processing, it need complex calculations in the frequency measurement process according to the laser pulse code signal time correlation to meet the request in optoelectronic countermeasures in semi-active laser guided weapons. To ensure accurately completing frequency measurement in a short time, it needed to carry out self-related process with the pulse arrival time series composed of pulse arrival time, calculate the signal repetition period, and then identify the letter type to achieve signal decoding from determining the time value, number and rank number in a signal cycle by Using CPLD and DSP for signal processing chip, designing a laser-guided signal frequency measurement in the pulse frequency measurement device, improving the signal processing capability through the appropriate software algorithms. In this article, we introduced the principle of frequency measurement of the device, described the hardware components of the device, the system works and software, analyzed the impact of some system factors on the accuracy of the measurement. The experimental results indicated that this system improve the accuracy of the measurement under the premise of volume, real-time, anti-interference, low power of the laser pulse frequency measuring device. The practicality of the design, reliability has been demonstrated from the experimental point of view.

Asymmetric Dual-Band Tracking Technique for Optimal Joint Processing of BDS B1I and B1C Signals.

PubMed

Wang, Chuhan; Cui, Xiaowei; Ma, Tianyi; Zhao, Sihao; Lu, Mingquan

2017-10-16

Along with the rapid development of the Global Navigation Satellite System (GNSS), satellite navigation signals have become more diversified, complex, and agile in adapting to increasing market demands. Various techniques have been developed for processing multiple navigation signals to achieve better performance in terms of accuracy, sensitivity, and robustness. This paper focuses on a technique for processing two signals with separate but adjacent center frequencies, such as B1I and B1C signals in the BeiDou global system. The two signals may differ in modulation scheme, power, and initial phase relation and can be processed independently by user receivers; however, the propagation delays of the two signals from a satellite are nearly identical as they are modulated on adjacent frequencies, share the same reference clock, and undergo nearly identical propagation paths to the receiver, resulting in strong coherence between the two signals. Joint processing of these signals can achieve optimal measurement performance due to the increased Gabor bandwidth and power. In this paper, we propose a universal scheme of asymmetric dual-band tracking (ASYM-DBT) to take advantage of the strong coherence, the increased Gabor bandwidth, and power of the two signals in achieving much-reduced thermal noise and more accurate ranging results when compared with the traditional single-band algorithm.

A mixed signal ECG processing platform with an adaptive sampling ADC for portable monitoring applications.

PubMed

Kim, Hyejung; Van Hoof, Chris; Yazicioglu, Refet Firat

2011-01-01

This paper describes a mixed-signal ECG processing platform with an 12-bit ADC architecture that can adapt its sampling rate according to the input signals rate of change. This enables the sampling of ECG signals with significantly reduced data rate without loss of information. The presented adaptive sampling scheme reduces the ADC power consumption, enables the processing of ECG signals with lower power consumption, and reduces the power consumption of the radio while streaming the ECG signals. The test results show that running a CWT-based R peak detection algorithm using the adaptively sampled ECG signals consumes only 45.6 μW and it leads to 36% less overall system power consumption.

Expanded Owens Valley Solar Array Science and Data Products

NASA Astrophysics Data System (ADS)

Gary, Dale E.; Hurford, G. J.; Nita, G. M.; Fleishman, G. D.; McTiernan, J. M.

2010-05-01

The Owens Valley Solar Array (OVSA) has been funded for major expansion, to create a university-based facility serving a broad scientific community, to keep the U.S. competitive in the field of solar radio physics. The project, funded by the National Science Foundation through the MRI-Recovery and Reinvestment program, will result in a world-class facility for scientific research at microwave radio frequencies (1-18 GHz) in solar and space weather physics. The project also includes an exciting program of targeted astronomical science. The solar science to be addressed focuses on the magnetic structure of the solar corona, on transient phenomena resulting from magnetic interactions, including the sudden release of energy and subsequent particle acceleration and heating, and on space weather phenomena. The project will support the scientific community by providing open data access and software tools for analysis of the data, to exploit synergies with on-going solar research in other wavelength bands. The New Jersey Institute of Technology (NJIT) will upgrade OVSA from its current complement of 7 antennas to a total of 15 by adding 8 new antennas, and will reinvest in the existing infrastructure by replacing the existing control systems, signal transmission, and signal processing with modern, far more capable and reliable systems based on new technology developed for the Frequency Agile Solar Radiotelescope (FASR). The project will be completed in time to provide solar-dedicated observations during the upcoming solar maximum in 2013 and beyond. We will detail the new science addressed by the expanded array, and provide an overview of the expected data products.

Overcoming low-alignment signal contrast induced alignment failure by alignment signal enhancement

NASA Astrophysics Data System (ADS)

Lee, Byeong Soo; Kim, Young Ha; Hwang, Hyunwoo; Lee, Jeongjin; Kong, Jeong Heung; Kang, Young Seog; Paarhuis, Bart; Kok, Haico; de Graaf, Roelof; Weichselbaum, Stefan; Droste, Richard; Mason, Christopher; Aarts, Igor; de Boeij, Wim P.

2016-03-01

Overlay is one of the key factors which enables optical lithography extension to 1X node DRAM manufacturing. It is natural that accurate wafer alignment is a prerequisite for good device overlay. However, alignment failures or misalignments are commonly observed in a fab. There are many factors which could induce alignment problems. Low alignment signal contrast is one of the main issues. Alignment signal contrast can be degraded by opaque stack materials or by alignment mark degradation due to processes like CMP. This issue can be compounded by mark sub-segmentation from design rules in combination with double or quadruple spacer process. Alignment signal contrast can be improved by applying new material or process optimization, which sometimes lead to the addition of another process-step with higher costs. If we can amplify the signal components containing the position information and reduce other unwanted signal and background contributions then we can improve alignment performance without process change. In this paper we use ASML's new alignment sensor (as was introduced and released on the NXT:1980Di) and sample wafers with special stacks which can induce poor alignment signal to demonstrate alignment and overlay improvement.

Adaptive filtering in biological signal processing.

PubMed

Iyer, V K; Ploysongsang, Y; Ramamoorthy, P A

1990-01-01

The high dependence of conventional optimal filtering methods on the a priori knowledge of the signal and noise statistics render them ineffective in dealing with signals whose statistics cannot be predetermined accurately. Adaptive filtering methods offer a better alternative, since the a priori knowledge of statistics is less critical, real time processing is possible, and the computations are less expensive for this approach. Adaptive filtering methods compute the filter coefficients "on-line", converging to the optimal values in the least-mean square (LMS) error sense. Adaptive filtering is therefore apt for dealing with the "unknown" statistics situation and has been applied extensively in areas like communication, speech, radar, sonar, seismology, and biological signal processing and analysis for channel equalization, interference and echo canceling, line enhancement, signal detection, system identification, spectral analysis, beamforming, modeling, control, etc. In this review article adaptive filtering in the context of biological signals is reviewed. An intuitive approach to the underlying theory of adaptive filters and its applicability are presented. Applications of the principles in biological signal processing are discussed in a manner that brings out the key ideas involved. Current and potential future directions in adaptive biological signal processing are also discussed.

Ant-mediated ecosystem processes are driven by trophic community structure but mainly by the environment.

PubMed

Salas-Lopez, Alex; Mickal, Houadria; Menzel, Florian; Orivel, Jérôme

2017-01-01

The diversity and functional identity of organisms are known to be relevant to the maintenance of ecosystem processes but can be variable in different environments. Particularly, it is uncertain whether ecosystem processes are driven by complementary effects or by dominant groups of species. We investigated how community structure (i.e., the diversity and relative abundance of biological entities) explains the community-level contribution of Neotropical ant communities to different ecosystem processes in different environments. Ants were attracted with food resources representing six ant-mediated ecosystem processes in four environments: ground and vegetation strata in cropland and forest habitats. The exploitation frequencies of the baits were used to calculate the taxonomic and trophic structures of ant communities and their contribution to ecosystem processes considered individually or in combination (i.e., multifunctionality). We then investigated whether community structure variables could predict ecosystem processes and whether such relationships were affected by the environment. We found that forests presented a greater biodiversity and trophic complementarity and lower dominance than croplands, but this did not affect ecosystem processes. In contrast, trophic complementarity was greater on the ground than on vegetation and was followed by greater resource exploitation levels. Although ant participation in ecosystem processes can be predicted by means of trophic-based indices, we found that variations in community structure and performance in ecosystem processes were best explained by environment. We conclude that determining the extent to which the dominance and complementarity of communities affect ecosystem processes in different environments requires a better understanding of resource availability to different species.

Research on signal processing method for total organic carbon of water quality online monitor

NASA Astrophysics Data System (ADS)

Ma, R.; Xie, Z. X.; Chu, D. Z.; Zhang, S. W.; Cao, X.; Wu, N.

2017-08-01

At present, there is no rapid, stable and effective approach of total organic carbon (TOC) measurement in the Marine environmental online monitoring field. Therefore, this paper proposes an online TOC monitor of chemiluminescence signal processing method. The weak optical signal detected by photomultiplier tube can be enhanced and converted by a series of signal processing module: phase-locked amplifier module, fourth-order band pass filter module and AD conversion module. After a long time of comparison test & measurement, compared with the traditional method, on the premise of sufficient accuracy, this chemiluminescence signal processing method can offer greatly improved measuring speed and high practicability for online monitoring.

Bistatic SAR: Signal Processing and Image Formation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wahl, Daniel E.; Yocky, David A.

This report describes the significant processing steps that were used to take the raw recorded digitized signals from the bistatic synthetic aperture RADAR (SAR) hardware built for the NCNS Bistatic SAR project to a final bistatic SAR image. In general, the process steps herein are applicable to bistatic SAR signals that include the direct-path signal and the reflected signal. The steps include preprocessing steps, data extraction to for a phase history, and finally, image format. Various plots and values will be shown at most steps to illustrate the processing for a bistatic COSMO SkyMed collection gathered on June 10, 2013more » on Kirtland Air Force Base, New Mexico.« less

Design of a dataway processor for a parallel image signal processing system

NASA Astrophysics Data System (ADS)

Nomura, Mitsuru; Fujii, Tetsuro; Ono, Sadayasu

1995-04-01

Recently, demands for high-speed signal processing have been increasing especially in the field of image data compression, computer graphics, and medical imaging. To achieve sufficient power for real-time image processing, we have been developing parallel signal-processing systems. This paper describes a communication processor called 'dataway processor' designed for a new scalable parallel signal-processing system. The processor has six high-speed communication links (Dataways), a data-packet routing controller, a RISC CORE, and a DMA controller. Each communication link operates at 8-bit parallel in a full duplex mode at 50 MHz. Moreover, data routing, DMA, and CORE operations are processed in parallel. Therefore, sufficient throughput is available for high-speed digital video signals. The processor is designed in a top- down fashion using a CAD system called 'PARTHENON.' The hardware is fabricated using 0.5-micrometers CMOS technology, and its hardware is about 200 K gates.

Estimating synchronous demographic changes across populations using hABC and its application for a herpetological community from northeastern Brazil.

PubMed

Gehara, Marcelo; Garda, Adrian A; Werneck, Fernanda P; Oliveira, Eliana F; da Fonseca, Emanuel M; Camurugi, Felipe; Magalhães, Felipe de M; Lanna, Flávia M; Sites, Jack W; Marques, Ricardo; Silveira-Filho, Ricardo; São Pedro, Vinícius A; Colli, Guarino R; Costa, Gabriel C; Burbrink, Frank T

2017-09-01

Many studies propose that Quaternary climatic cycles contracted and/or expanded the ranges of species and biomes. Strong expansion-contraction dynamics of biomes presume concerted demographic changes of associated fauna. The analysis of temporal concordance of demographic changes can be used to test the influence of Quaternary climate on diversification processes. Hierarchical approximate Bayesian computation (hABC) is a powerful and flexible approach that models genetic data from multiple species, and can be used to estimate the temporal concordance of demographic processes. Using available single-locus data, we can now perform large-scale analyses, both in terms of number of species and geographic scope. Here, we first compared the power of four alternative hABC models for a collection of single-locus data. We found that the model incorporating an a priori hypothesis about the timing of simultaneous demographic change had the best performance. Second, we applied the hABC models to a data set of seven squamate and four amphibian species occurring in the Seasonally Dry Tropical Forests (Caatinga) in northeastern Brazil, which, according to paleoclimatic evidence, experienced an increase in aridity during the Pleistocene. If this increase was important for the diversification of associated xeric-adapted species, simultaneous population expansions should be evident at the community level. We found a strong signal of synchronous population expansion in the Late Pleistocene, supporting the increase of the Caatinga during this time. This expansion likely enhanced the formation of communities adapted to high aridity and seasonality and caused regional extirpation of taxa adapted to wet forest. © 2017 John Wiley & Sons Ltd.

Managing soil microbial communities in grain production systems through cropping practices

NASA Astrophysics Data System (ADS)

Gupta, Vadakattu

2013-04-01

Cropping practices can significantly influence the composition and activity of soil microbial communities with consequences to plant growth and production. Plant type can affect functional capacity of different groups of biota in the soil surrounding their roots, rhizosphere, influencing plant nutrition, beneficial symbioses, pests and diseases and overall plant health and crop production. The interaction between different players in the rhizosphere is due to the plethora of carbon and nutritional compounds, root-specific chemical signals and growth regulators that originate from the plant and are modulated by the physico-chemical properties of soils. A number of plant and environmental factors and management practices can influence the quantity and quality of rhizodeposition and in turn affect the composition of rhizosphere biota communities, microbe-fauna interactions and biological processes. Some of the examples of rhizosphere interactions that are currently considered important are: proliferation of plant and variety specific genera or groups of microbiota, induction of genes involved in symbiosis and virulence, promoter activity in biocontrol agents and genes correlated with root adhesion and border cell quality and quantity. The observation of variety-based differences in rhizodeposition and associated changes in rhizosphere microbial diversity and function suggests the possibility for the development of varieties with specific root-microbe interactions targeted for soil type and environment i.e. designer rhizospheres. Spatial location of microorganisms in the heterogeneous field soil matrix can have significant impacts on biological processes. Therefore, for rhizosphere research to be effective in variable seasonal climate and soil conditions, it must be evaluated in the field and within a farming systems context. With the current focus on security of food to feed the growing global populations through sustainable agricultural production systems there is a need to develop innovative cropping systems that are both economically and environmentally sustainable.

Automatic Coregistration and orthorectification (ACRO) and subsequent mosaicing of NASA high-resolution imagery over the Mars MC11 quadrangle, using HRSC as a baseline

NASA Astrophysics Data System (ADS)

Sidiropoulos, Panagiotis; Muller, Jan-Peter; Watson, Gillian; Michael, Gregory; Walter, Sebastian

2018-02-01

This work presents the coregistered, orthorectified and mosaiced high-resolution products of the MC11 quadrangle of Mars, which have been processed using novel, fully automatic, techniques. We discuss the development of a pipeline that achieves fully automatic and parameter independent geometric alignment of high-resolution planetary images, starting from raw input images in NASA PDS format and following all required steps to produce a coregistered geotiff image, a corresponding footprint and useful metadata. Additionally, we describe the development of a radiometric calibration technique that post-processes coregistered images to make them radiometrically consistent. Finally, we present a batch-mode application of the developed techniques over the MC11 quadrangle to validate their potential, as well as to generate end products, which are released to the planetary science community, thus assisting in the analysis of Mars static and dynamic features. This case study is a step towards the full automation of signal processing tasks that are essential to increase the usability of planetary data, but currently, require the extensive use of human resources.

Neural Parallel Engine: A toolbox for massively parallel neural signal processing.

PubMed

Tam, Wing-Kin; Yang, Zhi

2018-05-01

Large-scale neural recordings provide detailed information on neuronal activities and can help elicit the underlying neural mechanisms of the brain. However, the computational burden is also formidable when we try to process the huge data stream generated by such recordings. In this study, we report the development of Neural Parallel Engine (NPE), a toolbox for massively parallel neural signal processing on graphical processing units (GPUs). It offers a selection of the most commonly used routines in neural signal processing such as spike detection and spike sorting, including advanced algorithms such as exponential-component-power-component (EC-PC) spike detection and binary pursuit spike sorting. We also propose a new method for detecting peaks in parallel through a parallel compact operation. Our toolbox is able to offer a 5× to 110× speedup compared with its CPU counterparts depending on the algorithms. A user-friendly MATLAB interface is provided to allow easy integration of the toolbox into existing workflows. Previous efforts on GPU neural signal processing only focus on a few rudimentary algorithms, are not well-optimized and often do not provide a user-friendly programming interface to fit into existing workflows. There is a strong need for a comprehensive toolbox for massively parallel neural signal processing. A new toolbox for massively parallel neural signal processing has been created. It can offer significant speedup in processing signals from large-scale recordings up to thousands of channels. Copyright © 2018 Elsevier B.V. All rights reserved.

Mapping biological process relationships and disease perturbations within a pathway network.

PubMed

Stoney, Ruth; Robertson, David L; Nenadic, Goran; Schwartz, Jean-Marc

2018-01-01

Molecular interaction networks are routinely used to map the organization of cellular function. Edges represent interactions between genes, proteins, or metabolites. However, in living cells, molecular interactions are dynamic, necessitating context-dependent models. Contextual information can be integrated into molecular interaction networks through the inclusion of additional molecular data, but there are concerns about completeness and relevance of this data. We developed an approach for representing the organization of human cellular processes using pathways as the nodes in a network. Pathways represent spatial and temporal sets of context-dependent interactions, generating a high-level network when linked together, which incorporates contextual information without the need for molecular interaction data. Analysis of the pathway network revealed linked communities representing functional relationships, comparable to those found in molecular networks, including metabolism, signaling, immunity, and the cell cycle. We mapped a range of diseases onto this network and find that pathways associated with diseases tend to be functionally connected, highlighting the perturbed functions that result in disease phenotypes. We demonstrated that disease pathways cluster within the network. We then examined the distribution of cancer pathways and showed that cancer pathways tend to localize within the signaling, DNA processes and immune modules, although some cancer-associated nodes are found in other network regions. Altogether, we generated a high-confidence functional network, which avoids some of the shortcomings faced by conventional molecular models. Our representation provides an intuitive functional interpretation of cellular organization, which relies only on high-quality pathway and Gene Ontology data. The network is available at https://data.mendeley.com/datasets/3pbwkxjxg9/1.

Complex networks of functional connectivity in a wetland reconnected to its floodplain

USGS Publications Warehouse

Larsen, Laurel G.; Newman, Susan; Saunders, Colin; Harvey, Judson

2017-01-01

Disturbances such as fire or flood, in addition to changing the local magnitude of ecological, hydrological, or biogeochemical processes, can also change their functional connectivity—how those processes interact in space. Complex networks offer promise for quantifying functional connectivity in watersheds. The approach resolves connections between nodes in space based on statistical similarities in perturbation signals (derived from solute time series) and is sensitive to a wider range of timescales than traditional mass-balance modeling. We use this approach to test hypotheses about how fire and flood impact ecological and biogeochemical dynamics in a wetland (Everglades, FL, USA) that was reconnected to its floodplain. Reintroduction of flow pulses after decades of separation by levees fundamentally reconfigured functional connectivity networks. The most pronounced expansion was that of the calcium network, which reflects periphyton dynamics and may represent an indirect influence of elevated nutrients, despite the comparatively smaller observed expansion of phosphorus networks. With respect to several solutes, periphyton acted as a “biotic filter,” shifting perturbations in water-quality signals to different timescales through slow but persistent transformations of the biotic community. The complex-networks approach also revealed portions of the landscape that operate in fundamentally different regimes with respect to dissolved oxygen, separated by a threshold in flow velocity of 1.2 cm/s, and suggested that complete removal of canals may be needed to restore connectivity with respect to biogeochemical processes. Fire reconfigured functional connectivity networks in a manner that reflected localized burn severity, but had a larger effect on the magnitude of solute concentrations.

Complex networks of functional connectivity in a wetland reconnected to its floodplain

NASA Astrophysics Data System (ADS)

Larsen, Laurel G.; Newman, Susan; Saunders, Colin; Harvey, Judson W.

2017-07-01

Disturbances such as fire or flood, in addition to changing the local magnitude of ecological, hydrological, or biogeochemical processes, can also change their functional connectivity—how those processes interact in space. Complex networks offer promise for quantifying functional connectivity in watersheds. The approach resolves connections between nodes in space based on statistical similarities in perturbation signals (derived from solute time series) and is sensitive to a wider range of timescales than traditional mass-balance modeling. We use this approach to test hypotheses about how fire and flood impact ecological and biogeochemical dynamics in a wetland (Everglades, FL, USA) that was reconnected to its floodplain. Reintroduction of flow pulses after decades of separation by levees fundamentally reconfigured functional connectivity networks. The most pronounced expansion was that of the calcium network, which reflects periphyton dynamics and may represent an indirect influence of elevated nutrients, despite the comparatively smaller observed expansion of phosphorus networks. With respect to several solutes, periphyton acted as a "biotic filter," shifting perturbations in water-quality signals to different timescales through slow but persistent transformations of the biotic community. The complex-networks approach also revealed portions of the landscape that operate in fundamentally different regimes with respect to dissolved oxygen, separated by a threshold in flow velocity of 1.2 cm/s, and suggested that complete removal of canals may be needed to restore connectivity with respect to biogeochemical processes. Fire reconfigured functional connectivity networks in a manner that reflected localized burn severity, but had a larger effect on the magnitude of solute concentrations.

75 FR 20811 - Proposed Information Collection; Comment Request; Produce Processor Profiles of Fish Processing...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-21

... population of an Alaska community with a fish processing plant can increase significantly during peak... workforce in a company galley, the interactions between seasonal processing workers and permanent residents of the community, and the history of the fish processing facility in the community. This type of...

Community Strategic Visioning as a Method to Define and Address Poverty: An Analysis from Select Rural Montana Communities

ERIC Educational Resources Information Center

Lachapelle, Paul; Austin, Eric; Clark, Daniel

2010-01-01

Community strategic visioning is a citizen-based planning process in which diverse sectors of a community collectively determine a future state and coordinate a plan of action. Twenty-one communities in rural Montana participated in a multi-phase poverty reduction program that culminated in a community strategic vision process. Research on this…

Microbial community related to lysozyme digestion process for boosting waste activated sludge biodegradability.

PubMed

Xin, Xiao-Dong; He, Jun-Guo; Qiu, Wei; Tang, Jian; Liu, Tian-Tian

2015-01-01

Waste activated sludge from a lab-scale sequencing batch reactor was used to investigate the potential relation of microbial community with lysozyme digestion process for sludge solubilization. The results showed the microbial community shifted conspicuously as sludge suffered lysozyme digestion. Soluble protein and polysaccharide kept an increasing trend in solution followed with succession of microbial community. The rise of lysozyme dosage augmented the dissimilarity among communities in various digested sludge. A negative relationship presented between community diversity and lysozyme digestion process under various lysozyme/TS from 0 to 240min (correlation coefficient R(2) exceeded 0.9). Pareto-Lorenz curves demonstrated that microbial community tended to be even with sludge disintegration process by lysozyme. Finally, with diversity (H) decrease and community distribution getting even, the SCOD/TCOD increased steadily in solution which suggested the sludge with high community diversity and uneven population distribution might have tremendous potential for improving their biodegradability by lysozyme digestion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quality of cyclone early warning services: a case study in remote off-shore island in Bangladesh

NASA Astrophysics Data System (ADS)

Ashrafi, Z. M.; Mahmud, S.; Mahbub, A. Q. M.

2015-12-01

Geographic location, the unique natural setting of the country and its tropical monsoon climate modify and regulate the climatic condition, makes Bangladesh more vulnerable to cyclones and storm surges. Previous studies have showed that 80-90 % of global losses and 53 % of total cyclone-related deaths worldwide, occur in Bangladesh and out of which, 42% of cyclone-caused deaths were recorded in the last two centuries. The Cyclone Preparedness Program (CPP) is a unique joint program under the initiative of Government of Bangladesh and Bangladesh Red Crescent Society that provides a robust cyclone early warning (CEW) system for the 13 coastal districts in Bangladesh. CPP ensures rapid dissemination of official Bangladesh Meteorological Department's CEW signals to these communities. However, inconsistent CEW services are reported in several of these coastal communities. This study offered the quality assessment of CPP CEW services in Nijhum Island, a highly populated remotely located off-shore island in Bangladesh. Primary rural appraisal (household survey, focus group discussion and expert interview) were used for field data collection and Likert scale, for data analysis. Study revealed that cyclone early warning signal dissemination were restricted to small area covering only 35 percent of the total population. Moreover, local inhabitants had very poor understanding about disseminated CEW signals (flag signaling system, signal number & severity) although CPP initiated several training program to build and raise awareness. Consequently, people remained inactive during cyclone and reluctant to seek shelter which resulted in lack of proper post-disaster management. Moreover, local people had concern regarding accuracy of CEW signals disseminated by CPP. To ensure last mile connectivity of CEW services, it is highly recommended that local people should be given more training and awareness on CEW signals and how to respond to the same.

LOAPEX: The Long-Range Ocean Acoustic Propagation EXperiment

DTIC Science & Technology

2009-01-01

roughly 4200 m, the OBS/H packages at 5000 m received the LOAPEX transmissions. 4) Signal Processing : In general, signal processing for all receptions is...coherently in the time domain. To optimize processing , is based on the coherence time of the received signal and the resulting pro- cessing gain is . The...replica of the transmission. This process produces a triangular-shaped pulse with a time resolution of 1-b length, or 27 ms, and additional processing

Consequences of spring phytodetritus sedimentation on the benthic compartment along a depth gradient in the Eastern English Channel.

PubMed

Denis, Lionel; Desroy, Nicolas

2008-11-01

Phaeocystis blooms are of major importance in the Eastern English Channel, where they significantly contribute to spring organic matter input with chlorophyll concentrations commonly higher than 30 microgl(-1) in the water column. Post-bloom deposition of Phaeocystis derived mucilaginous compounds has been shown to have a major importance on benthic intertidal systems, but resulting mineralization processes and consequences on the macrobenthic compartment remain poorly documented in subtidal areas. In this frame, a study was performed along the French coast of the English Channel to quantify mineralization processes, as well as potential consequences on subtidal sediments, especially their geochemistry and associated macrofaunal communities. Seven stations were studied along a depth gradient during four cruises: before (March), during (April, May) and after (June) the spring bloom. Sediment characteristics and organic carbon content were described, as well as sediment-water fluxes of oxygen and ammonium. Macrofaunal characteristics were also analyzed. Stations were chosen as representative of the various benthic communities present in the area, which are directly linked to the granulometric characteristics of the sediments. To account for the general functioning of the water column, characterized by a coastal flow where higher concentrations of Phaeocystis are generally recorded, similar communities were sampled inshore and offshore, when possible: (i) the Abra alba community located only close to the coast, (ii) the Ophelia borealis community located inshore and offshore, and (iii) the Amphioxus lanceolatus community located inshore and offshore. Generally, low exchange rates of oxygen and ammonium were measured (respectively, in the range 50-150 micromol O2 m(-2)h(-1) and -25 to 35 micromol NH4+ m(-2)h(-1)) between the water column and the muddy-sand to coarse sand permeable sediments, as a consequence of the low organic carbon content due to the high hydrodynamic forcing. As a consequence of organic matter accumulation in surficial sediments probably resulting from Phaeocystis post-bloom deposition, an increase of sediment oxygen demand and ammonium release was clearly evidenced up to 660 micromol O2 m(-2)h(-1) and 205 micromol NH4+ m(-2)h(-1) in May, only in stations located close to the coast (<8 kms), in the A. alba community. Despite those significant biogeochemical changes in surficial sediments, no significant consequence was pointed out on macrofauna, neither in the O. borealis and A. lanceolatus communities, nor in the coastal A. alba community. Most of the temporal variations recorded might be attributed to the common spring population dynamics, but this study highlights the potential use of geochemical parameters as a forewarning signal of benthic disequilibrium.

An Integrated Framework to Analyze Local Decision Making and Adaptation to Sea-Level Rise in Coastal Regions in Santos-Brazil, Broward County-USA and Selsey-UK

NASA Astrophysics Data System (ADS)

Marengo, J. A.; Muller-Karger, F. E.; Pelling, M.; Reynolds, C. J.; Merril, S. B.; Nunes, L. H.; Paterson, S.; Gray, A.; Lockman, J. T.; Kartez, J.; Moreira, F.; Greco, R.; Harari, J.; Souza, C. G.; Alves, L. M.; Hosokawa, E.; Tabuchi, E.

2016-12-01

One of the clear signals of present climate change is sea level rise (SLR). There is mounting evidence of other changes, including warmer temperatures in many localities, and changes in the intensity and frequency of extreme meteorological events, including wind, rain, and waves. A rising sea level combined with these factors and tides is expected to affect coastal communities through a number of processes, including increased risk of flooding and contamination of water sources. An international collaboration between Brazil, the United Kingdom, and the United States was designed to evaluate local decision making processes and to open convening space for local urban managers to reflect on possible actions toward adaption to SLR and the constraints imposed by framing administrative and institutional structures. The overall goal of the project is to help coastal communities better understand factors that facilitate or hinder their intrinsic, local decision-making processes related to planning for adaptation to risk. The project carried out these tests in 2014 and 2015 in one coastal city in each partnering nation. The framework was designed by an interdisciplinary team that incorporated social and natural scientists from these three nations, and which included local government officials. To support the overall goal, this paper 1) discusses some aspects of adaptive capacity and participant survey research conducted through the project, 2) presents technical modelling results for adaptation options that may reduce the potential damages of SLR and storm surge in each location, and 3) identifies project design considerations for similar transnational adaptation projects.

Digital signal processing in the radio science stability analyzer

NASA Technical Reports Server (NTRS)

Greenhall, C. A.

1995-01-01

The Telecommunications Division has built a stability analyzer for testing Deep Space Network installations during flight radio science experiments. The low-frequency part of the analyzer operates by digitizing wave signals with bandwidths between 80 Hz and 45 kHz. Processed outputs include spectra of signal, phase, amplitude, and differential phase; time series of the same quantities; and Allan deviation of phase and differential phase. This article documents the digital signal-processing methods programmed into the analyzer.

Relative Roles of Deterministic and Stochastic Processes in Driving the Vertical Distribution of Bacterial Communities in a Permafrost Core from the Qinghai-Tibet Plateau, China.

PubMed

Hu, Weigang; Zhang, Qi; Tian, Tian; Li, Dingyao; Cheng, Gang; Mu, Jing; Wu, Qingbai; Niu, Fujun; Stegen, James C; An, Lizhe; Feng, Huyuan

2015-01-01

Understanding the processes that influence the structure of biotic communities is one of the major ecological topics, and both stochastic and deterministic processes are expected to be at work simultaneously in most communities. Here, we investigated the vertical distribution patterns of bacterial communities in a 10-m-long soil core taken within permafrost of the Qinghai-Tibet Plateau. To get a better understanding of the forces that govern these patterns, we examined the diversity and structure of bacterial communities, and the change in community composition along the vertical distance (spatial turnover) from both taxonomic and phylogenetic perspectives. Measures of taxonomic and phylogenetic beta diversity revealed that bacterial community composition changed continuously along the soil core, and showed a vertical distance-decay relationship. Multiple stepwise regression analysis suggested that bacterial alpha diversity and phylogenetic structure were strongly correlated with soil conductivity and pH but weakly correlated with depth. There was evidence that deterministic and stochastic processes collectively drived bacterial vertically-structured pattern. Bacterial communities in five soil horizons (two originated from the active layer and three from permafrost) of the permafrost core were phylogenetically random, indicator of stochastic processes. However, we found a stronger effect of deterministic processes related to soil pH, conductivity, and organic carbon content that were structuring the bacterial communities. We therefore conclude that the vertical distribution of bacterial communities was governed primarily by deterministic ecological selection, although stochastic processes were also at work. Furthermore, the strong impact of environmental conditions (for example, soil physicochemical parameters and seasonal freeze-thaw cycles) on these communities underlines the sensitivity of permafrost microorganisms to climate change and potentially subsequent permafrost thaw.

Relative Roles of Deterministic and Stochastic Processes in Driving the Vertical Distribution of Bacterial Communities in a Permafrost Core from the Qinghai-Tibet Plateau, China

PubMed Central

Tian, Tian; Li, Dingyao; Cheng, Gang; Mu, Jing; Wu, Qingbai; Niu, Fujun; Stegen, James C.; An, Lizhe; Feng, Huyuan

2015-01-01

Understanding the processes that influence the structure of biotic communities is one of the major ecological topics, and both stochastic and deterministic processes are expected to be at work simultaneously in most communities. Here, we investigated the vertical distribution patterns of bacterial communities in a 10-m-long soil core taken within permafrost of the Qinghai-Tibet Plateau. To get a better understanding of the forces that govern these patterns, we examined the diversity and structure of bacterial communities, and the change in community composition along the vertical distance (spatial turnover) from both taxonomic and phylogenetic perspectives. Measures of taxonomic and phylogenetic beta diversity revealed that bacterial community composition changed continuously along the soil core, and showed a vertical distance-decay relationship. Multiple stepwise regression analysis suggested that bacterial alpha diversity and phylogenetic structure were strongly correlated with soil conductivity and pH but weakly correlated with depth. There was evidence that deterministic and stochastic processes collectively drived bacterial vertically-structured pattern. Bacterial communities in five soil horizons (two originated from the active layer and three from permafrost) of the permafrost core were phylogenetically random, indicator of stochastic processes. However, we found a stronger effect of deterministic processes related to soil pH, conductivity, and organic carbon content that were structuring the bacterial communities. We therefore conclude that the vertical distribution of bacterial communities was governed primarily by deterministic ecological selection, although stochastic processes were also at work. Furthermore, the strong impact of environmental conditions (for example, soil physicochemical parameters and seasonal freeze-thaw cycles) on these communities underlines the sensitivity of permafrost microorganisms to climate change and potentially subsequent permafrost thaw. PMID:26699734

Designer cell signal processing circuits for biotechnology

PubMed Central

Bradley, Robert W.; Wang, Baojun

2015-01-01

Microorganisms are able to respond effectively to diverse signals from their environment and internal metabolism owing to their inherent sophisticated information processing capacity. A central aim of synthetic biology is to control and reprogramme the signal processing pathways within living cells so as to realise repurposed, beneficial applications ranging from disease diagnosis and environmental sensing to chemical bioproduction. To date most examples of synthetic biological signal processing have been built based on digital information flow, though analogue computing is being developed to cope with more complex operations and larger sets of variables. Great progress has been made in expanding the categories of characterised biological components that can be used for cellular signal manipulation, thereby allowing synthetic biologists to more rationally programme increasingly complex behaviours into living cells. Here we present a current overview of the components and strategies that exist for designer cell signal processing and decision making, discuss how these have been implemented in prototype systems for therapeutic, environmental, and industrial biotechnological applications, and examine emerging challenges in this promising field. PMID:25579192

How Community Development Programmes Can Foster Re-Engagement with Learning in Disadvantaged Communities: Leadership as Process

ERIC Educational Resources Information Center

Millar, Pat; Kilpatrick, Sue

2005-01-01

Family and community capacity building projects in Tasmania are attempting to address the disadvantage of communities marginalised by socio-economic and other influences. Collaborations between the projects, community members and groups, and education and training organisations, have resulted in a leadership process which has fostered reengagement…

Frequency-feature based antistrong-disturbance signal processing method and system for vortex flowmeter with single sensor

NASA Astrophysics Data System (ADS)

Xu, Ke-Jun; Luo, Qing-Lin; Wang, Gang; Liu, San-Shan; Kang, Yi-Bo

2010-07-01

Digital signal processing methods have been applied to vortex flowmeter for extracting the useful information from noisy output of the vortex flow sensor. But these approaches are unavailable when the power of the mechanical vibration noise is larger than that of the vortex flow signal. In order to solve this problem, an antistrong-disturbance signal processing method is proposed based on frequency features of the vortex flow signal and mechanical vibration noise for the vortex flowmeter with single sensor. The frequency bandwidth of the vortex flow signal is different from that of the mechanical vibration noise. The autocorrelation function can represent bandwidth features of the signal and noise. The output of the vortex flow sensor is processed by the spectrum analysis, filtered by bandpass filters, and calculated by autocorrelation function at the fixed delaying time and at τ =0 to obtain ratios. The frequency corresponding to the minimal ratio is regarded as the vortex flow frequency. With an ultralow-power microcontroller, a digital signal processing system is developed to implement the antistrong-disturbance algorithm, and at the same time to ensure low-power and two-wire mode for meeting the requirement of process instrumentation. The water flow-rate calibration and vibration test experiments are conducted, and the experimental results show that both the algorithm and system are effective.

Frequency-feature based antistrong-disturbance signal processing method and system for vortex flowmeter with single sensor.

PubMed

Xu, Ke-Jun; Luo, Qing-Lin; Wang, Gang; Liu, San-Shan; Kang, Yi-Bo

2010-07-01

Digital signal processing methods have been applied to vortex flowmeter for extracting the useful information from noisy output of the vortex flow sensor. But these approaches are unavailable when the power of the mechanical vibration noise is larger than that of the vortex flow signal. In order to solve this problem, an antistrong-disturbance signal processing method is proposed based on frequency features of the vortex flow signal and mechanical vibration noise for the vortex flowmeter with single sensor. The frequency bandwidth of the vortex flow signal is different from that of the mechanical vibration noise. The autocorrelation function can represent bandwidth features of the signal and noise. The output of the vortex flow sensor is processed by the spectrum analysis, filtered by bandpass filters, and calculated by autocorrelation function at the fixed delaying time and at tau=0 to obtain ratios. The frequency corresponding to the minimal ratio is regarded as the vortex flow frequency. With an ultralow-power microcontroller, a digital signal processing system is developed to implement the antistrong-disturbance algorithm, and at the same time to ensure low-power and two-wire mode for meeting the requirement of process instrumentation. The water flow-rate calibration and vibration test experiments are conducted, and the experimental results show that both the algorithm and system are effective.

A model system for targeted drug release triggered by biomolecular signals logically processed through enzyme logic networks.

PubMed

Mailloux, Shay; Halámek, Jan; Katz, Evgeny

2014-03-07

A new Sense-and-Act system was realized by the integration of a biocomputing system, performing analytical processes, with a signal-responsive electrode. A drug-mimicking release process was triggered by biomolecular signals processed by different logic networks, including three concatenated AND logic gates or a 3-input OR logic gate. Biocatalytically produced NADH, controlled by various combinations of input signals, was used to activate the electrochemical system. A biocatalytic electrode associated with signal-processing "biocomputing" systems was electrically connected to another electrode coated with a polymer film, which was dissolved upon the formation of negative potential releasing entrapped drug-mimicking species, an enzyme-antibody conjugate, operating as a model for targeted immune-delivery and consequent "prodrug" activation. The system offers great versatility for future applications in controlled drug release and personalized medicine.

Processing circuit with asymmetry corrector and convolutional encoder for digital data

NASA Technical Reports Server (NTRS)

Pfiffner, Harold J. (Inventor)

1987-01-01

A processing circuit is provided for correcting for input parameter variations, such as data and clock signal symmetry, phase offset and jitter, noise and signal amplitude, in incoming data signals. An asymmetry corrector circuit performs the correcting function and furnishes the corrected data signals to a convolutional encoder circuit. The corrector circuit further forms a regenerated clock signal from clock pulses in the incoming data signals and another clock signal at a multiple of the incoming clock signal. These clock signals are furnished to the encoder circuit so that encoded data may be furnished to a modulator at a high data rate for transmission.

Phenotypic Microdiversity and Phylogenetic Signal Analysis of Traits Related to Social Interaction in Bacillus spp. from Sediment Communities.

PubMed

Rodríguez-Torres, María Dolores; Islas-Robles, África; Gómez-Lunar, Zulema; Delaye, Luis; Hernández-González, Ismael; Souza, Valeria; Travisano, Michael; Olmedo-Álvarez, Gabriela

2017-01-01

Understanding the relationship between phylogeny and predicted traits is important to uncover the dimension of the predictive power of a microbial composition approach. Numerous works have addressed the taxonomic composition of bacteria in communities, but little is known about trait heterogeneity in closely related bacteria that co-occur in communities. We evaluated a sample of 467 isolates from the Churince water system of the Cuatro Cienegas Basin (CCB), enriched for Bacillus spp. The 16S rRNA gene revealed a random distribution of taxonomic groups within this genus among 11 sampling sites. A subsample of 141 Bacillus spp. isolates from sediment, with seven well-represented species was chosen to evaluate the heterogeneity and the phylogenetic signal of phenotypic traits that are known to diverge within small clades, such as substrate utilization, and traits that are conserved deep in the lineage, such as prototrophy, swarming and biofilm formation. We were especially interested in evaluating social traits, such as swarming and biofilm formation, for which cooperation is needed to accomplish a multicellular behavior and for which there is little information from natural communities. The phylogenetic distribution of traits, evaluated by the Purvis and Fritz's D statistics approached a Brownian model of evolution. Analysis of the phylogenetic relatedness of the clusters of members sharing the trait using consenTRAIT algorithm, revealed more clustering and deeper phylogenetic signal for prototrophy, biofilm and swimming compared to the data obtained for substrate utilization. The explanation to the observed Brownian evolution of social traits could be either loss due to complete dispensability or to compensated trait loss due to the availability of public goods. Since many of the evaluated traits can be considered to be collective action traits, such as swarming, motility and biofilm formation, the observed microdiversity within taxonomic groups might be explained by distributed functions in structured communities.

Community-Partnered Project-Based Studio Pedagogy: Developing a Framework and Exploring the Impact on Faculty in Art and Design Higher Education

ERIC Educational Resources Information Center

Corn, Melanie E.

2013-01-01

Young would-be artists flock to art schools to learn from masters and immerse themselves in a study of the aesthetic histories, techniques, and theories that will inform their practices. However, the emergence of community-partnered project-based (CP) studio courses at many independent art colleges signals a fundamental shift in art and design…

Probabilistic Signal Recovery and Random Matrices

DTIC Science & Technology

2016-12-08

applications in statistics , biomedical data analysis, quantization, dimen- sion reduction, and networks science. 1. High-dimensional inference and geometry Our...low-rank approxima- tion, with applications to community detection in networks, Annals of Statistics 44 (2016), 373–400. [7] C. Le, E. Levina, R...approximation, with applications to community detection in networks, Annals of Statistics 44 (2016), 373–400. C. Le, E. Levina, R. Vershynin, Concentration

Signaling network of dendritic cells in response to pathogens: a community-input supported knowledgebase.

PubMed

Patil, Sonali; Pincas, Hanna; Seto, Jeremy; Nudelman, German; Nudelman, Irina; Sealfon, Stuart C

2010-10-07

Dendritic cells are antigen-presenting cells that play an essential role in linking the innate and adaptive immune systems. Much research has focused on the signaling pathways triggered upon infection of dendritic cells by various pathogens. The high level of activity in the field makes it desirable to have a pathway-based resource to access the information in the literature. Current pathway diagrams lack either comprehensiveness, or an open-access editorial interface. Hence, there is a need for a dependable, expertly curated knowledgebase that integrates this information into a map of signaling networks. We have built a detailed diagram of the dendritic cell signaling network, with the goal of providing researchers with a valuable resource and a facile method for community input. Network construction has relied on comprehensive review of the literature and regular updates. The diagram includes detailed depictions of pathways activated downstream of different pathogen recognition receptors such as Toll-like receptors, retinoic acid-inducible gene-I-like receptors, C-type lectin receptors and nucleotide-binding oligomerization domain-like receptors. Initially assembled using CellDesigner software, it provides an annotated graphical representation of interactions stored in Systems Biology Mark-up Language. The network, which comprises 249 nodes and 213 edges, has been web-published through the Biological Pathway Publisher software suite. Nodes are annotated with PubMed references and gene-related information, and linked to a public wiki, providing a discussion forum for updates and corrections. To gain more insight into regulatory patterns of dendritic cell signaling, we analyzed the network using graph-theory methods: bifan, feedforward and multi-input convergence motifs were enriched. This emphasis on activating control mechanisms is consonant with a network that subserves persistent and coordinated responses to pathogen detection. This map represents a navigable aid for presenting a consensus view of the current knowledge on dendritic cell signaling that can be continuously improved through contributions of research community experts. Because the map is available in a machine readable format, it can be edited and may assist researchers in data analysis. Furthermore, the availability of a comprehensive knowledgebase might help further research in this area such as vaccine development. The dendritic cell signaling knowledgebase is accessible at http://tsb.mssm.edu/pathwayPublisher/DC_pathway/DC_pathway_index.html.

Advancing coalition theory: the effect of coalition factors on community capacity mediated by member engagement

PubMed Central

Kegler, Michelle C.; Swan, Deanne W.

2012-01-01

Community coalitions have the potential to enhance a community’s capacity to engage in effective problem solving for a range of community concerns. Although numerous studies have documented correlations between member engagement and coalition processes and structural characteristics, fewer have examined associations between coalition factors and community capacity outcomes. The current study uses data from an evaluation of the California Healthy Cities and Communities program to examine pathways between coalition factors (i.e. membership, processes), member engagement (i.e. participation, satisfaction) and community capacity as hypothesized by the Community Coalition Action Theory (CCAT). Surveys were completed by 231 members of 19 healthy cities and communities coalitions. Multilevel mediation analyses were used to examine possible mediating effects of member engagement on three community capacity indicators: new skills, sense of community and social capital. Results generally supported CCAT. Member engagement mediated the effects of leadership and staffing on community capacity outcomes. Results also showed that member engagement mediated several relationships between process variables (i.e. task focus, cohesion) and community capacity, but several unmediated direct effects were also observed. This suggests that although member engagement does explain some relationships, it alone is not sufficient to explain how coalition processes influence indicators of community capacity. PMID:21911845

Changes of soil prokaryotic communities after clear-cutting in a karst forest: evidences for cutting-based disturbance promoting deterministic processes.

PubMed

Zhang, Xiao; Liu, Shirong; Li, Xiangzhen; Wang, Jingxin; Ding, Qiong; Wang, Hui; Tian, Chao; Yao, Minjie; An, Jiaxing; Huang, Yongtao

2016-03-01

To understand the temporal responses of soil prokaryotic communities to clear-cutting disturbance, we examined the changes in soil bacterial and archaeal community composition, structure and diversity along a chronosequence of forest successional restoration using high-throughput 16S rRNA gene sequencing. Our results demonstrated that clear-cutting significantly altered soil bacterial community structure, while no significant shifts of soil archaeal communities were observed. The hypothesis that soil bacterial communities would become similar to those of surrounding intact primary forest with natural regeneration was supported by the shifts in the bacterial community composition and structure. Bacterial community diversity patterns induced by clear-cutting were consistent with the intermediate disturbance hypothesis. Dynamics of bacterial communities was mostly driven by soil properties, which collectively explained more than 70% of the variation in bacterial community composition. Community assembly data revealed that clear-cutting promoted the importance of the deterministic processes in shaping bacterial communities, coinciding with the resultant low resource environments. But assembly processes in the secondary forest returned a similar level compared to the intact primary forest. These findings suggest that bacterial community dynamics may be predictable during the natural recovery process. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Determining causal miRNAs and their signaling cascade in diseases using an influence diffusion model.

PubMed

Nalluri, Joseph J; Rana, Pratip; Barh, Debmalya; Azevedo, Vasco; Dinh, Thang N; Vladimirov, Vladimir; Ghosh, Preetam

2017-08-15

In recent studies, miRNAs have been found to be extremely influential in many of the essential biological processes. They exhibit a self-regulatory mechanism through which they act as positive/negative regulators of expression of genes and other miRNAs. This has direct implications in the regulation of various pathophysiological conditions, signaling pathways and different types of cancers. Studying miRNA-disease associations has been an extensive area of research; however deciphering miRNA-miRNA network regulatory patterns in several diseases remains a challenge. In this study, we use information diffusion theory to quantify the influence diffusion in a miRNA-miRNA regulation network across multiple disease categories. Our proposed methodology determines the critical disease specific miRNAs which play a causal role in their signaling cascade and hence may regulate disease progression. We extensively validate our framework using existing computational tools from the literature. Furthermore, we implement our framework on a comprehensive miRNA expression data set for alcohol dependence and identify the causal miRNAs for alcohol-dependency in patients which were validated by the phase-shift in their expression scores towards the early stages of the disease. Finally, our computational framework for identifying causal miRNAs implicated in diseases is available as a free online tool for the greater scientific community.

Phosphoproteomic network analysis in the sea urchin Strongylocentrotus purpuratus reveals new candidates in egg activation.

PubMed

Guo, Hongbo; Garcia-Vedrenne, Ana Elisa; Isserlin, Ruth; Lugowski, Andrew; Morada, Anthony; Sun, Alex; Miao, Yishen; Kuzmanov, Uros; Wan, Cuihong; Ma, Hongyue; Foltz, Kathy; Emili, Andrew

2015-12-01

Fertilization triggers a dynamic symphony of molecular transformations induced by a rapid rise in intracellular calcium. Most prominent are surface alterations, metabolic activation, cytoskeletal reorganization, and cell-cycle reentry. While the activation process appears to be broadly evolutionarily conserved, and protein phosphorylation is known to play a key role, the signaling networks mediating the response to fertilization are not well described. To address this gap, we performed a time course phosphoproteomic analysis of egg activation in the sea urchin Strongylocentrotus purpuratus, a system that offers biochemical tractability coupled with exquisite synchronicity. By coupling large-scale phosphopeptide enrichment with unbiased quantitative MS, we identified striking changes in global phosphoprotein patterns at 2- and 5-min postfertilization as compared to unfertilized eggs. Overall, we mapped 8796 distinct phosphosite modifications on 2833 phosphoproteins, of which 15% were differentially regulated in early egg activation. Activated kinases were identified by phosphosite mapping, while enrichment analyses revealed conserved signaling cascades not previously associated with egg activation. This work represents the most comprehensive study of signaling associated with egg activation to date, suggesting novel mechanisms that can be experimentally tested and providing a valuable resource for the broader research community. All MS data have been deposited in the ProteomeXchange with identifier PXD002239 (http://proteomecentral.proteomexchange.org/dataset/PXD002239). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis in natural time domain of geoelectric time series monitored prior two strong earthquakes occurred in Mexico

NASA Astrophysics Data System (ADS)

Ramírez-Rojas, A.; Flores-Marquez, L. E.

2009-12-01

The short-time prediction of seismic phenomena is currently an important problem in the scientific community. In particular, the electromagnetic processes associated with seismic events take in great interest since the VAN method was implemented. The most important features of this methodology are the seismic electrical signals (SES) observed prior to strong earthquakes. SES has been observed in the electromagnetic series linked to EQs in Greece, Japan and Mexico. By mean of the so-called natural time domain, introduced by Varotsos et al. (2001), they could characterize signals of dichotomic nature observed in different systems, like SES and ionic current fluctuations in membrane channels. In this work we analyze SES observed in geoelectric time series monitored in Guerrero, México. Our analysis concern with two strong earthquakes occurred, on October 24, 1993 (M=6.6) and September 14, 1995 (M=7.3). The time series of the first one displayed a seismic electric signal six days before the main shock and for the second case the time series displayed dichotomous-like fluctuations some months before the EQ. In this work we present the first results of the analysis in natural time domain for the two cases which seems to be agreeing with the results reported by Varotsos. P. Varotsos, N. Sarlis, and E. Skordas, Practica of the Athens Academy 76, 388 (2001).

UHF Signal Processing and Pattern Recognition of Partial Discharge in Gas-Insulated Switchgear Using Chromatic Methodology

PubMed Central

Wang, Xiaohua; Li, Xi; Rong, Mingzhe; Xie, Dingli; Ding, Dan; Wang, Zhixiang

2017-01-01

The ultra-high frequency (UHF) method is widely used in insulation condition assessment. However, UHF signal processing algorithms are complicated and the size of the result is large, which hinders extracting features and recognizing partial discharge (PD) patterns. This article investigated the chromatic methodology that is novel in PD detection. The principle of chromatic methodologies in color science are introduced. The chromatic processing represents UHF signals sparsely. The UHF signals obtained from PD experiments were processed using chromatic methodology and characterized by three parameters in chromatic space (H, L, and S representing dominant wavelength, signal strength, and saturation, respectively). The features of the UHF signals were studied hierarchically. The results showed that the chromatic parameters were consistent with conventional frequency domain parameters. The global chromatic parameters can be used to distinguish UHF signals acquired by different sensors, and they reveal the propagation properties of the UHF signal in the L-shaped gas-insulated switchgear (GIS). Finally, typical PD defect patterns had been recognized by using novel chromatic parameters in an actual GIS tank and good performance of recognition was achieved. PMID:28106806

UHF Signal Processing and Pattern Recognition of Partial Discharge in Gas-Insulated Switchgear Using Chromatic Methodology.

PubMed

Wang, Xiaohua; Li, Xi; Rong, Mingzhe; Xie, Dingli; Ding, Dan; Wang, Zhixiang

2017-01-18

The ultra-high frequency (UHF) method is widely used in insulation condition assessment. However, UHF signal processing algorithms are complicated and the size of the result is large, which hinders extracting features and recognizing partial discharge (PD) patterns. This article investigated the chromatic methodology that is novel in PD detection. The principle of chromatic methodologies in color science are introduced. The chromatic processing represents UHF signals sparsely. The UHF signals obtained from PD experiments were processed using chromatic methodology and characterized by three parameters in chromatic space ( H , L , and S representing dominant wavelength, signal strength, and saturation, respectively). The features of the UHF signals were studied hierarchically. The results showed that the chromatic parameters were consistent with conventional frequency domain parameters. The global chromatic parameters can be used to distinguish UHF signals acquired by different sensors, and they reveal the propagation properties of the UHF signal in the L-shaped gas-insulated switchgear (GIS). Finally, typical PD defect patterns had been recognized by using novel chromatic parameters in an actual GIS tank and good performance of recognition was achieved.

Maximum-likelihood spectral estimation and adaptive filtering techniques with application to airborne Doppler weather radar. Thesis Technical Report No. 20

NASA Technical Reports Server (NTRS)

Lai, Jonathan Y.

1994-01-01

This dissertation focuses on the signal processing problems associated with the detection of hazardous windshears using airborne Doppler radar when weak weather returns are in the presence of strong clutter returns. In light of the frequent inadequacy of spectral-processing oriented clutter suppression methods, we model a clutter signal as multiple sinusoids plus Gaussian noise, and propose adaptive filtering approaches that better capture the temporal characteristics of the signal process. This idea leads to two research topics in signal processing: (1) signal modeling and parameter estimation, and (2) adaptive filtering in this particular signal environment. A high-resolution, low SNR threshold maximum likelihood (ML) frequency estimation and signal modeling algorithm is devised and proves capable of delineating both the spectral and temporal nature of the clutter return. Furthermore, the Least Mean Square (LMS) -based adaptive filter's performance for the proposed signal model is investigated, and promising simulation results have testified to its potential for clutter rejection leading to more accurate estimation of windspeed thus obtaining a better assessment of the windshear hazard.

MIMO signal progressing with RLSCMA algorithm for multi-mode multi-core optical transmission system

NASA Astrophysics Data System (ADS)

Bi, Yuan; Liu, Bo; Zhang, Li-jia; Xin, Xiang-jun; Zhang, Qi; Wang, Yong-jun; Tian, Qing-hua; Tian, Feng; Mao, Ya-ya

2018-01-01

In the process of transmitting signals of multi-mode multi-core fiber, there will be mode coupling between modes. The mode dispersion will also occur because each mode has different transmission speed in the link. Mode coupling and mode dispersion will cause damage to the useful signal in the transmission link, so the receiver needs to deal received signal with digital signal processing, and compensate the damage in the link. We first analyzes the influence of mode coupling and mode dispersion in the process of transmitting signals of multi-mode multi-core fiber, then presents the relationship between the coupling coefficient and dispersion coefficient. Then we carry out adaptive signal processing with MIMO equalizers based on recursive least squares constant modulus algorithm (RLSCMA). The MIMO equalization algorithm offers adaptive equalization taps according to the degree of crosstalk in cores or modes, which eliminates the interference among different modes and cores in space division multiplexing(SDM) transmission system. The simulation results show that the distorted signals are restored efficiently with fast convergence speed.

Maglev Train Signal Processing Architecture Based on Nonlinear Discrete Tracking Differentiator.

PubMed

Wang, Zhiqiang; Li, Xiaolong; Xie, Yunde; Long, Zhiqiang

2018-05-24

In a maglev train levitation system, signal processing plays an important role for the reason that some sensor signals are prone to be corrupted by noise due to the harsh installation and operation environment of sensors and some signals cannot be acquired directly via sensors. Based on these concerns, an architecture based on a new type of nonlinear second-order discrete tracking differentiator is proposed. The function of this signal processing architecture includes filtering signal noise and acquiring needed signals for levitation purposes. The proposed tracking differentiator possesses the advantages of quick convergence, no fluttering, and simple calculation. Tracking differentiator's frequency characteristics at different parameter values are studied in this paper. The performance of this new type of tracking differentiator is tested in a MATLAB simulation and this tracking-differentiator is implemented in Very-High-Speed Integrated Circuit Hardware Description Language (VHDL). In the end, experiments are conducted separately on a test board and a maglev train model. Simulation and experiment results show that the performance of this novel signal processing architecture can fulfill the real system requirement.

A novel time-domain signal processing algorithm for real time ventricular fibrillation detection

NASA Astrophysics Data System (ADS)

Monte, G. E.; Scarone, N. C.; Liscovsky, P. O.; Rotter S/N, P.

2011-12-01

This paper presents an application of a novel algorithm for real time detection of ECG pathologies, especially ventricular fibrillation. It is based on segmentation and labeling process of an oversampled signal. After this treatment, analyzing sequence of segments, global signal behaviours are obtained in the same way like a human being does. The entire process can be seen as a morphological filtering after a smart data sampling. The algorithm does not require any ECG digital signal pre-processing, and the computational cost is low, so it can be embedded into the sensors for wearable and permanent applications. The proposed algorithms could be the input signal description to expert systems or to artificial intelligence software in order to detect other pathologies.

Investigation of signal processing algorithms for an embedded microcontroller-based wearable pulse oximeter.

PubMed

Johnston, W S; Mendelson, Y

2006-01-01

Despite steady progress in the miniaturization of pulse oximeters over the years, significant challenges remain since advanced signal processing must be implemented efficiently in real-time by a relatively small size wearable device. The goal of this study was to investigate several potential digital signal processing algorithms for computing arterial oxygen saturation (SpO(2)) and heart rate (HR) in a battery-operated wearable reflectance pulse oximeter that is being developed in our laboratory for use by medics and first responders in the field. We found that a differential measurement approach, combined with a low-pass filter (LPF), yielded the most suitable signal processing technique for estimating SpO(2), while a signal derivative approach produced the most accurate HR measurements.

Towards a Standard Mixed-Signal Parallel Processing Architecture for Miniature and Microrobotics.

PubMed

Sadler, Brian M; Hoyos, Sebastian

2014-01-01

The conventional analog-to-digital conversion (ADC) and digital signal processing (DSP) architecture has led to major advances in miniature and micro-systems technology over the past several decades. The outlook for these systems is significantly enhanced by advances in sensing, signal processing, communications and control, and the combination of these technologies enables autonomous robotics on the miniature to micro scales. In this article we look at trends in the combination of analog and digital (mixed-signal) processing, and consider a generalized sampling architecture. Employing a parallel analog basis expansion of the input signal, this scalable approach is adaptable and reconfigurable, and is suitable for a large variety of current and future applications in networking, perception, cognition, and control.

Towards a Standard Mixed-Signal Parallel Processing Architecture for Miniature and Microrobotics

PubMed Central

Sadler, Brian M; Hoyos, Sebastian

2014-01-01

The conventional analog-to-digital conversion (ADC) and digital signal processing (DSP) architecture has led to major advances in miniature and micro-systems technology over the past several decades. The outlook for these systems is significantly enhanced by advances in sensing, signal processing, communications and control, and the combination of these technologies enables autonomous robotics on the miniature to micro scales. In this article we look at trends in the combination of analog and digital (mixed-signal) processing, and consider a generalized sampling architecture. Employing a parallel analog basis expansion of the input signal, this scalable approach is adaptable and reconfigurable, and is suitable for a large variety of current and future applications in networking, perception, cognition, and control. PMID:26601042

Optical Profilometers Using Adaptive Signal Processing

NASA Technical Reports Server (NTRS)

Hall, Gregory A.; Youngquist, Robert; Mikhael, Wasfy

2006-01-01

A method of adaptive signal processing has been proposed as the basis of a new generation of interferometric optical profilometers for measuring surfaces. The proposed profilometers would be portable, hand-held units. Sizes could be thus reduced because the adaptive-signal-processing method would make it possible to substitute lower-power coherent light sources (e.g., laser diodes) for white light sources and would eliminate the need for most of the optical components of current white-light profilometers. The adaptive-signal-processing method would make it possible to attain scanning ranges of the order of decimeters in the proposed profilometers.

Community Opinion and Satisfaction with the Leadership at an Urban Community Educational Learning Center during an Organizational Transformation Process: A Frontline Perspective from Community Stakeholders

ERIC Educational Resources Information Center

Lewis, Joseph Lee

2013-01-01

This study examined selected community stakeholders' perception of the current leadership at their local community educational learning center during an organizational transformation and cultural change process. The transition from a community college to an educational learning center, mandated in 2006 by the Accredition Commission and agreed on…

SIG. Signal Processing, Analysis, & Display

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernandez, J.; Lager, D.; Azevedo, S.

1992-01-22

SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG; a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time and frequency-domain signals includingmore » operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments, commenting lines, defining commands, and automatic execution for each item in a `repeat` sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.« less

SIG. Signal Processing, Analysis, & Display

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernandez, J.; Lager, D.; Azevedo, S.

1992-01-22

SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time-and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG - a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time and frequency-domain signals includingmore » operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments, commenting lines, defining commands, and automatic execution for each item in a repeat sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.« less

Digital signal processing for velocity measurements in dynamical material's behaviour studies.

PubMed

Devlaminck, Julien; Luc, Jérôme; Chanal, Pierre-Yves

2014-03-01

In this work, we describe different configurations of optical fiber interferometers (types Michelson and Mach-Zehnder) used to measure velocities during dynamical material's behaviour studies. We detail the algorithms of processing developed and optimized to improve the performance of these interferometers especially in terms of time and frequency resolutions. Three methods of analysis of interferometric signals were studied. For Michelson interferometers, the time-frequency analysis of signals by Short-Time Fourier Transform (STFT) is compared to a time-frequency analysis by Continuous Wavelet Transform (CWT). The results have shown that the CWT was more suitable than the STFT for signals with low signal-to-noise, and low velocity and high acceleration areas. For Mach-Zehnder interferometers, the measurement is carried out by analyzing the phase shift between three interferometric signals (Triature processing). These three methods of digital signal processing were evaluated, their measurement uncertainties estimated, and their restrictions or operational limitations specified from experimental results performed on a pulsed power machine.

Algebraic signal processing theory: 2-D spatial hexagonal lattice.

PubMed

Pünschel, Markus; Rötteler, Martin

2007-06-01

We develop the framework for signal processing on a spatial, or undirected, 2-D hexagonal lattice for both an infinite and a finite array of signal samples. This framework includes the proper notions of z-transform, boundary conditions, filtering or convolution, spectrum, frequency response, and Fourier transform. In the finite case, the Fourier transform is called discrete triangle transform. Like the hexagonal lattice, this transform is nonseparable. The derivation of the framework makes it a natural extension of the algebraic signal processing theory that we recently introduced. Namely, we construct the proper signal models, given by polynomial algebras, bottom-up from a suitable definition of hexagonal space shifts using a procedure provided by the algebraic theory. These signal models, in turn, then provide all the basic signal processing concepts. The framework developed in this paper is related to Mersereau's early work on hexagonal lattices in the same way as the discrete cosine and sine transforms are related to the discrete Fourier transform-a fact that will be made rigorous in this paper.

Improving the signal analysis for in vivo photoacoustic flow cytometry

NASA Astrophysics Data System (ADS)

Niu, Zhenyu; Yang, Ping; Wei, Dan; Tang, Shuo; Wei, Xunbin

2015-03-01

At early stage of cancer, a small number of circulating tumor cells (CTCs) appear in the blood circulation. Thus, early detection of malignant circulating tumor cells has great significance for timely treatment to reduce the cancer death rate. We have developed an in vivo photoacoustic flow cytometry (PAFC) to monitor the metastatic process of CTCs and record the signals from target cells. Information of target cells which is helpful to the early therapy would be obtained through analyzing and processing the signals. The raw signal detected from target cells often contains some noise caused by electronic devices, such as background noise and thermal noise. We choose the Wavelet denoising method to effectively distinguish the target signal from background noise. Processing in time domain and frequency domain would be combined to analyze the signal after denoising. This algorithm contains time domain filter and frequency transformation. The frequency spectrum image of the signal contains distinctive features that can be used to analyze the property of target cells or particles. The PAFC technique can detect signals from circulating tumor cells or other particles. The processing methods have a great potential for analyzing signals accurately and rapidly.

EMG amplifier with wireless data transmission

NASA Astrophysics Data System (ADS)

Kowalski, Grzegorz; Wildner, Krzysztof

2017-08-01

Wireless medical diagnostics is a trend in modern technology used in medicine. This paper presents a concept of realization, architecture of hardware and software implementation of an elecromyography signal (EMG) amplifier with wireless data transmission. This amplifier consists of three components: analogue processing of bioelectric signal module, micro-controller circuit and an application enabling data acquisition via a personal computer. The analogue bioelectric signal processing circuit receives electromyography signals from the skin surface, followed by initial analogue processing and preparation of the signals for further digital processing. The second module is a micro-controller circuit designed to wirelessly transmit the electromyography signals from the analogue signal converter to a personal computer. Its purpose is to eliminate the need for wired connections between the patient and the data logging device. The third block is a computer application designed to display the transmitted electromyography signals, as well as data capture and analysis. Its purpose is to provide a graphical representation of the collected data. The entire device has been thoroughly tested to ensure proper functioning. In use, the device displayed the captured electromyography signal from the arm of the patient. Amplitude- frequency characteristics were set in order to investigate the bandwidth and the overall gain of the device.

Forewarning of Debris flows using Intelligent Geophones

NASA Astrophysics Data System (ADS)

PK, I.; Ramesh, M. V.

2017-12-01

Landslides are one of the major catastrophic disasters that cause significant damage to human life and civil structures. Heavy rainfall on landslide prone areas can lead to most dangerous debris flow, where the materials such as mud, sand, soil, rock, water and air will move with greater velocity down the mountain. This sudden slope instability can lead to loss of human life and infrastructure. According to our knowledge, till now no one could identify the minutest factors that lead to initiation of the landslide. In this work, we aim to study the landslide phenomena deeply, using the landslide laboratory set up in our university. This unique mechanical simulator for landslide initiation is equipped with the capability to generate rainfall, seepage, etc., in the laboratory setup. Using this setup, we aim to study several landslide initiation scenarios generated by varying different parameters. The complete setup will be equipped with heterogeneous sensors such as rain gauge, moisture sensor, pore pressure sensor, strain gauges, tiltmeter, inclinometer, extensometer, and geophones. Our work will focus on the signals received from the intelligent geophone system for identifying the underground vibrations during a debris flow. Using the large amount of signals derived from the laboratory set up, we have performed detailed signal processing and data analysis to determine the fore warning signals captured by these heterogeneous sensors. Detailed study of these heterogeneous signals has provided the insights to forewarning the community based on the signals generated during the laboratory tests. In this work we will describe the details of the design, development, methodology, results, inferences and the suggestion for the next step to detect and forewarn the students. The response of intelligent geophone sensors at the time of failure, failure style and subsequent debris flow for heterogeneous soil layers were studied, thus helping in the development of fore warning systems for debris flows.

Extracting Independent Local Oscillatory Geophysical Signals by Geodetic Tropospheric Delay

NASA Technical Reports Server (NTRS)

Botai, O. J.; Combrinck, L.; Sivakumar, V.; Schuh, H.; Bohm, J.

2010-01-01

Zenith Tropospheric Delay (ZTD) due to water vapor derived from space geodetic techniques and numerical weather prediction simulated-reanalysis data exhibits non-linear and non-stationary properties akin to those in the crucial geophysical signals of interest to the research community. These time series, once decomposed into additive (and stochastic) components, have information about the long term global change (the trend) and other interpretable (quasi-) periodic components such as seasonal cycles and noise. Such stochastic component(s) could be a function that exhibits at most one extremum within a data span or a monotonic function within a certain temporal span. In this contribution, we examine the use of the combined Ensemble Empirical Mode Decomposition (EEMD) and Independent Component Analysis (ICA): the EEMD-ICA algorithm to extract the independent local oscillatory stochastic components in the tropospheric delay derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) over six geodetic sites (HartRAO, Hobart26, Wettzell, Gilcreek, Westford, and Tsukub32). The proposed methodology allows independent geophysical processes to be extracted and assessed. Analysis of the quality index of the Independent Components (ICs) derived for each cluster of local oscillatory components (also called the Intrinsic Mode Functions (IMFs)) for all the geodetic stations considered in the study demonstrate that they are strongly site dependent. Such strong dependency seems to suggest that the localized geophysical signals embedded in the ZTD over the geodetic sites are not correlated. Further, from the viewpoint of non-linear dynamical systems, four geophysical signals the Quasi-Biennial Oscillation (QBO) index derived from the NCEP/NCAR reanalysis, the Southern Oscillation Index (SOI) anomaly from NCEP, the SIDC monthly Sun Spot Number (SSN), and the Length of Day (LoD) are linked to the extracted signal components from ZTD. Results from the synchronization analysis show that ZTD and the geophysical signals exhibit (albeit subtle) site dependent phase synchronization index.

Research on photodiode detector-based spatial transient light detection and processing system

NASA Astrophysics Data System (ADS)

Liu, Meiying; Wang, Hu; Liu, Yang; Zhao, Hui; Nan, Meng

2016-10-01

In order to realize real-time signal identification and processing of spatial transient light, the features and the energy of the captured target light signal are first described and quantitatively calculated. Considering that the transient light signal has random occurrence, a short duration and an evident beginning and ending, a photodiode detector based spatial transient light detection and processing system is proposed and designed in this paper. This system has a large field of view and is used to realize non-imaging energy detection of random, transient and weak point target under complex background of spatial environment. Weak signal extraction under strong background is difficult. In this paper, considering that the background signal changes slowly and the target signal changes quickly, filter is adopted for signal's background subtraction. A variable speed sampling is realized by the way of sampling data points with a gradually increased interval. The two dilemmas that real-time processing of large amount of data and power consumption required by the large amount of data needed to be stored are solved. The test results with self-made simulative signal demonstrate the effectiveness of the design scheme. The practical system could be operated reliably. The detection and processing of the target signal under the strong sunlight background was realized. The results indicate that the system can realize real-time detection of target signal's characteristic waveform and monitor the system working parameters. The prototype design could be used in a variety of engineering applications.

Coherent broadband sonar signal processing with the environmentally corrected matched filter

NASA Astrophysics Data System (ADS)

Camin, Henry John, III

The matched filter is the standard approach for coherently processing active sonar signals, where knowledge of the transmitted waveform is used in the detection and parameter estimation of received echoes. Matched filtering broadband signals provides higher levels of range resolution and reverberation noise suppression than can be realized through narrowband processing. Since theoretical processing gains are proportional to the signal bandwidth, it is typically desirable to utilize the widest band signals possible. However, as signal bandwidth increases, so do environmental effects that tend to decrease correlation between the received echo and the transmitted waveform. This is especially true for ultra wideband signals, where the bandwidth exceeds an octave or approximately 70% fractional bandwidth. This loss of coherence often results in processing gains and range resolution much lower than theoretically predicted. Wiener filtering, commonly used in image processing to improve distorted and noisy photos, is investigated in this dissertation as an approach to correct for these environmental effects. This improved signal processing, Environmentally Corrected Matched Filter (ECMF), first uses a Wiener filter to estimate the environmental transfer function and then again to correct the received signal using this estimate. This process can be viewed as a smarter inverse or whitening filter that adjusts behavior according to the signal to noise ratio across the spectrum. Though the ECMF is independent of bandwidth, it is expected that ultra wideband signals will see the largest improvement, since they tend to be more impacted by environmental effects. The development of the ECMF and demonstration of improved parameter estimation with its use are the primary emphases in this dissertation. Additionally, several new contributions to the field of sonar signal processing made in conjunction with the development of the ECMF are described. A new, nondimensional wideband ambiguity function is presented as a way to view the behavior of the matched filter with and without the decorrelating environmental effects; a new, integrated phase broadband angle estimation method is developed and compared to existing methods; and a new, asymptotic offset phase angle variance model is presented. Several data sets are used to demonstrate these new contributions. High fidelity Sonar Simulation Toolset (SST) synthetic data is used to characterize the theoretical performance. Two in-water data sets were used to verify assumptions that were made during the development of the ECMF. Finally, a newly collected in-air data set containing ultra wideband signals was used in lieu of a cost prohibitive underwater experiment to demonstrate the effectiveness of the ECMF at improving parameter estimates.

Disturbance by an endemic rodent in an arid shrubland is a habitat filter: effects on plant invasion and taxonomical, functional and phylogenetic community structure

PubMed Central

Escobedo, Víctor M.; Rios, Rodrigo S.; Salgado-Luarte, Cristian; Stotz, Gisela C.

2017-01-01

Abstract Background and Aims Disturbance often drives plant invasion and may modify community assembly. However, little is known about how these modifications of community patterns occur in terms of taxonomic, functional and phylogenetic structure. This study evaluated in an arid shrubland the influence of disturbance by an endemic rodent on community functional divergence and phylogenetic structure as well as on plant invasion. It was expected that disturbance would operate as a habitat filter favouring exotic species with short life cycles. Methods Sixteen plots were sampled along a disturbance gradient caused by the endemic fossorial rodent Spalacopus cyanus, measuring community parameters and estimating functional divergence for life history traits (functional dispersion index) and the relative contribution to functional divergence of exotic and native species. The phylogenetic signal (Pagel’s lambda) and phylogenetic community structure (mean phylogenetic distance and mean nearest taxon phylogenetic distance) were also estimated. The use of a continuous approach to the disturbance gradient allowed the identification of non-linear relationships between disturbance and community parameters. Key Results The relationship between disturbance and both species richness and abundance was positive for exotic species and negative for native species. Disturbance modified community composition, and exotic species were associated with more disturbed sites. Disturbance increased trait convergence, which resulted in phylogenetic clustering because traits showed a significant phylogenetic signal. The relative contribution of exotic species to functional divergence increased, while that of natives decreased, with disturbance. Exotic and native species were not phylogenetically distinct. Conclusions Disturbance by rodents in this arid shrubland constitutes a habitat filter over phylogeny-dependent life history traits, leading to phylogenetic clustering, and drives invasion by favouring species with short life cycles. Results can be explained by high phenotypic and phylogenetic resemblance between exotic and native species. The use of continuous gradients when studying the effects of disturbance on community assembly is advocated. PMID:28087661

Masked multichannel analyzer

DOEpatents

Winiecki, A.L.; Kroop, D.C.; McGee, M.K.; Lenkszus, F.R.

1984-01-01

An analytical instrument and particularly a time-of-flight-mass spectrometer for processing a large number of analog signals irregularly spaced over a spectrum, with programmable masking of portions of the spectrum where signals are unlikely in order to reduce memory requirements and/or with a signal capturing assembly having a plurality of signal capturing devices fewer in number than the analog signals for use in repeated cycles within the data processing time period.

Masked multichannel analyzer

DOEpatents

Winiecki, Alan L.; Kroop, David C.; McGee, Marilyn K.; Lenkszus, Frank R.

1986-01-01

An analytical instrument and particularly a time-of-flight-mass spectrometer for processing a large number of analog signals irregularly spaced over a spectrum, with programmable masking of portions of the spectrum where signals are unlikely in order to reduce memory requirements and/or with a signal capturing assembly having a plurality of signal capturing devices fewer in number than the analog signals for use in repeated cycles within the data processing time period.

Directional dual-tree complex wavelet packet transforms for processing quadrature signals.

PubMed

Serbes, Gorkem; Gulcur, Halil Ozcan; Aydin, Nizamettin

2016-03-01

Quadrature signals containing in-phase and quadrature-phase components are used in many signal processing applications in every field of science and engineering. Specifically, Doppler ultrasound systems used to evaluate cardiovascular disorders noninvasively also result in quadrature format signals. In order to obtain directional blood flow information, the quadrature outputs have to be preprocessed using methods such as asymmetrical and symmetrical phasing filter techniques. These resultant directional signals can be employed in order to detect asymptomatic embolic signals caused by small emboli, which are indicators of a possible future stroke, in the cerebral circulation. Various transform-based methods such as Fourier and wavelet were frequently used in processing embolic signals. However, most of the times, the Fourier and discrete wavelet transforms are not appropriate for the analysis of embolic signals due to their non-stationary time-frequency behavior. Alternatively, discrete wavelet packet transform can perform an adaptive decomposition of the time-frequency axis. In this study, directional discrete wavelet packet transforms, which have the ability to map directional information while processing quadrature signals and have less computational complexity than the existing wavelet packet-based methods, are introduced. The performances of proposed methods are examined in detail by using single-frequency, synthetic narrow-band, and embolic quadrature signals.

Multi-channel non-invasive fetal electrocardiography detection using wavelet decomposition

NASA Astrophysics Data System (ADS)

Almeida, Javier; Ruano, Josué; Corredor, Germán.; Romo-Bucheli, David; Navarro-Vargas, José Ricardo; Romero, Eduardo

2017-11-01

Non-invasive fetal electrocardiography (fECG) has attracted the medical community because of the importance of fetal monitoring. However, its implementation in clinical practice is challenging: the fetal signal has a low Signal- to-Noise-Ratio and several signal sources are present in the maternal abdominal electrocardiography (AECG). This paper presents a novel method to detect the fetal signal from a multi-channel maternal AECG. The method begins by applying filters and signal detrending the AECG signals. Afterwards, the maternal QRS complexes are identified and subtracted. The residual signals are used to detect the fetal QRS complex. Intervals of these signals are analyzed by using a wavelet decomposition. The resulting representation feds a previously trained Random Forest (RF) classifier that identifies signal intervals associated to fetal QRS complex. The method was evaluated on a public available dataset: the Physionet2013 challenge. A set of 50 maternal AECG records were used to train the RF classifier. The evaluation was carried out in signals intervals extracted from additional 25 maternal AECG. The proposed method yielded an 83:77% accuracy in the fetal QRS complex classification task.

Carbon allocation and carbon isotope fluxes in the plant-soil-atmosphere continuum: a review

NASA Astrophysics Data System (ADS)

Brüggemann, N.; Gessler, A.; Kayler, Z.; Keel, S. G.; Badeck, F.; Barthel, M.; Boeckx, P.; Buchmann, N.; Brugnoli, E.; Esperschütz, J.; Gavrichkova, O.; Ghashghaie, J.; Gomez-Casanovas, N.; Keitel, C.; Knohl, A.; Kuptz, D.; Palacio, S.; Salmon, Y.; Uchida, Y.; Bahn, M.

2011-11-01

The terrestrial carbon (C) cycle has received increasing interest over the past few decades, however, there is still a lack of understanding of the fate of newly assimilated C allocated within plants and to the soil, stored within ecosystems and lost to the atmosphere. Stable carbon isotope studies can give novel insights into these issues. In this review we provide an overview of an emerging picture of plant-soil-atmosphere C fluxes, as based on C isotope studies, and identify processes determining related C isotope signatures. The first part of the review focuses on isotopic fractionation processes within plants during and after photosynthesis. The second major part elaborates on plant-internal and plant-rhizosphere C allocation patterns at different time scales (diel, seasonal, interannual), including the speed of C transfer and time lags in the coupling of assimilation and respiration, as well as the magnitude and controls of plant-soil C allocation and respiratory fluxes. Plant responses to changing environmental conditions, the functional relationship between the physiological and phenological status of plants and C transfer, and interactions between C, water and nutrient dynamics are discussed. The role of the C counterflow from the rhizosphere to the aboveground parts of the plants, e.g. via CO2 dissolved in the xylem water or as xylem-transported sugars, is highlighted. The third part is centered around belowground C turnover, focusing especially on above- and belowground litter inputs, soil organic matter formation and turnover, production and loss of dissolved organic C, soil respiration and CO2 fixation by soil microbes. Furthermore, plant controls on microbial communities and activity via exudates and litter production as well as microbial community effects on C mineralization are reviewed. A further part of the paper is dedicated to physical interactions between soil CO2 and the soil matrix, such as CO2 diffusion and dissolution processes within the soil profile. Finally, we highlight state-of-the-art stable isotope methodologies and their latest developments. From the presented evidence we conclude that there exists a tight coupling of physical, chemical and biological processes involved in C cycling and C isotope fluxes in the plant-soil-atmosphere system. Generally, research using information from C isotopes allows an integrated view of the different processes involved. However, complex interactions among the range of processes complicate or currently impede the interpretation of isotopic signals in CO2 or organic compounds at the plant and ecosystem level. This review tries to identify present knowledge gaps in correctly interpreting carbon stable isotope signals in the plant-soil-atmosphere system and how future research approaches could contribute to closing these gaps.

Hybrid photonic signal processing

NASA Astrophysics Data System (ADS)

Ghauri, Farzan Naseer

This thesis proposes research of novel hybrid photonic signal processing systems in the areas of optical communications, test and measurement, RF signal processing and extreme environment optical sensors. It will be shown that use of innovative hybrid techniques allows design of photonic signal processing systems with superior performance parameters and enhanced capabilities. These applications can be divided into domains of analog-digital hybrid signal processing applications and free-space---fiber-coupled hybrid optical sensors. The analog-digital hybrid signal processing applications include a high-performance analog-digital hybrid MEMS variable optical attenuator that can simultaneously provide high dynamic range as well as high resolution attenuation controls; an analog-digital hybrid MEMS beam profiler that allows high-power watt-level laser beam profiling and also provides both submicron-level high resolution and wide area profiling coverage; and all optical transversal RF filters that operate on the principle of broadband optical spectral control using MEMS and/or Acousto-Optic tunable Filters (AOTF) devices which can provide continuous, digital or hybrid signal time delay and weight selection. The hybrid optical sensors presented in the thesis are extreme environment pressure sensors and dual temperature-pressure sensors. The sensors employ hybrid free-space and fiber-coupled techniques for remotely monitoring a system under simultaneous extremely high temperatures and pressures.

Simplified signal processing for impedance spectroscopy with spectrally sparse sequences

NASA Astrophysics Data System (ADS)

Annus, P.; Land, R.; Reidla, M.; Ojarand, J.; Mughal, Y.; Min, M.

2013-04-01

Classical method for measurement of the electrical bio-impedance involves excitation with sinusoidal waveform. Sinusoidal excitation at fixed frequency points enables wide variety of signal processing options, most general of them being Fourier transform. Multiplication with two quadrature waveforms at desired frequency could be easily accomplished both in analogue and in digital domains, even simplest quadrature square waves can be considered, which reduces signal processing task in analogue domain to synchronous switching followed by low pass filter, and in digital domain requires only additions. So called spectrally sparse excitation sequences (SSS), which have been recently introduced into bio-impedance measurement domain, are very reasonable choice when simultaneous multifrequency excitation is required. They have many good properties, such as ease of generation and good crest factor compared to similar multisinusoids. Typically, the usage of discrete or fast Fourier transform in signal processing step is considered so far. Usage of simplified methods nevertheless would reduce computational burden, and enable simpler, less costly and less energy hungry signal processing platforms. Accuracy of the measurement with SSS excitation when using different waveforms for quadrature demodulation will be compared in order to evaluate the feasibility of the simplified signal processing. Sigma delta modulated sinusoid (binary signal) is considered to be a good alternative for a synchronous demodulation.

Setting health priorities in a community: a case example

PubMed Central

Sousa, Fábio Alexandre Melo do Rego; Goulart, Maria José Garcia; Braga, Antonieta Manuela dos Santos; Medeiros, Clara Maria Oliveira; Rego, Débora Cristina Martins; Vieira, Flávio Garcia; Pereira, Helder José Alves da Rocha; Tavares, Helena Margarida Correia Vicente; Loura, Marta Maria Puim

2017-01-01

ABSTRACT OBJECTIVE To describe the methodology used in the process of setting health priorities for community intervention in a community of older adults. METHODS Based on the results of a health diagnosis related to active aging, a prioritization process was conceived to select the priority intervention problem. The process comprised four successive phases of problem analysis and classification: (1) grouping by level of similarity, (2) classification according to epidemiological criteria, (3) ordering by experts, and (4) application of the Hanlon method. These stages combined, in an integrated manner, the views of health team professionals, community nursing and gerontology experts, and the actual community. RESULTS The first stage grouped the identified problems by level of similarity, comprising a body of 19 issues for analysis. In the second stage these problems were classified by the health team members by epidemiological criteria (size, vulnerability, and transcendence). The nine most relevant problems resulting from the second stage of the process were submitted to expert analysis and the five most pertinent problems were selected. The last step identified the priority issue for intervention in this specific community with the participation of formal and informal community leaders: Low Social Interaction in Community Participation. CONCLUSIONS The prioritization process is a key step in health planning, enabling the identification of priority problems to intervene in a given community at a given time. There are no default formulas for selecting priority issues. It is up to each community intervention team to define its own process with different methods/techniques that allow the identification of and intervention in needs classified as priority by the community. PMID:28273229

Acoustic emission signal processing for rolling bearing running state assessment using compressive sensing

NASA Astrophysics Data System (ADS)

Liu, Chang; Wu, Xing; Mao, Jianlin; Liu, Xiaoqin

2017-07-01

In the signal processing domain, there has been growing interest in using acoustic emission (AE) signals for the fault diagnosis and condition assessment instead of vibration signals, which has been advocated as an effective technique for identifying fracture, crack or damage. The AE signal has high frequencies up to several MHz which can avoid some signals interference, such as the parts of bearing (i.e. rolling elements, ring and so on) and other rotating parts of machine. However, acoustic emission signal necessitates advanced signal sampling capabilities and requests ability to deal with large amounts of sampling data. In this paper, compressive sensing (CS) is introduced as a processing framework, and then a compressive features extraction method is proposed. We use it for extracting the compressive features from compressively-sensed data directly, and also prove the energy preservation properties. First, we study the AE signals under the CS framework. The sparsity of AE signal of the rolling bearing is checked. The observation and reconstruction of signal is also studied. Second, we present a method of extraction AE compressive feature (AECF) from compressively-sensed data directly. We demonstrate the energy preservation properties and the processing of the extracted AECF feature. We assess the running state of the bearing using the AECF trend. The AECF trend of the running state of rolling bearings is consistent with the trend of traditional features. Thus, the method is an effective way to evaluate the running trend of rolling bearings. The results of the experiments have verified that the signal processing and the condition assessment based on AECF is simpler, the amount of data required is smaller, and the amount of computation is greatly reduced.

Surface Electromyography Signal Processing and Classification Techniques

PubMed Central

Chowdhury, Rubana H.; Reaz, Mamun B. I.; Ali, Mohd Alauddin Bin Mohd; Bakar, Ashrif A. A.; Chellappan, Kalaivani; Chang, Tae. G.

2013-01-01

Electromyography (EMG) signals are becoming increasingly important in many applications, including clinical/biomedical, prosthesis or rehabilitation devices, human machine interactions, and more. However, noisy EMG signals are the major hurdles to be overcome in order to achieve improved performance in the above applications. Detection, processing and classification analysis in electromyography (EMG) is very desirable because it allows a more standardized and precise evaluation of the neurophysiological, rehabitational and assistive technological findings. This paper reviews two prominent areas; first: the pre-processing method for eliminating possible artifacts via appropriate preparation at the time of recording EMG signals, and second: a brief explanation of the different methods for processing and classifying EMG signals. This study then compares the numerous methods of analyzing EMG signals, in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above. PMID:24048337

Testing Signal-Detection Models of Yes/No and Two-Alternative Forced-Choice Recognition Memory

ERIC Educational Resources Information Center

Jang, Yoonhee; Wixted, John T.; Huber, David E.

2009-01-01

The current study compared 3 models of recognition memory in their ability to generalize across yes/no and 2-alternative forced-choice (2AFC) testing. The unequal-variance signal-detection model assumes a continuous memory strength process. The dual-process signal-detection model adds a thresholdlike recollection process to a continuous…

SPROC: A multiple-processor DSP IC

NASA Technical Reports Server (NTRS)

Davis, R.

1991-01-01

A large, single-chip, multiple-processor, digital signal processing (DSP) integrated circuit (IC) fabricated in HP-Cmos34 is presented. The innovative architecture is best suited for analog and real-time systems characterized by both parallel signal data flows and concurrent logic processing. The IC is supported by a powerful development system that transforms graphical signal flow graphs into production-ready systems in minutes. Automatic compiler partitioning of tasks among four on-chip processors gives the IC the signal processing power of several conventional DSP chips.

Fourier analysis and signal processing by use of the Moebius inversion formula

NASA Technical Reports Server (NTRS)

Reed, Irving S.; Yu, Xiaoli; Shih, Ming-Tang; Tufts, Donald W.; Truong, T. K.

1990-01-01

A novel Fourier technique for digital signal processing is developed. This approach to Fourier analysis is based on the number-theoretic method of the Moebius inversion of series. The Fourier transform method developed is shown also to yield the convolution of two signals. A computer simulation shows that this method for finding Fourier coefficients is quite suitable for digital signal processing. It competes with the classical FFT (fast Fourier transform) approach in terms of accuracy, complexity, and speed.

LWT Based Sensor Node Signal Processing in Vehicle Surveillance Distributed Sensor Network

NASA Astrophysics Data System (ADS)

Cha, Daehyun; Hwang, Chansik

Previous vehicle surveillance researches on distributed sensor network focused on overcoming power limitation and communication bandwidth constraints in sensor node. In spite of this constraints, vehicle surveillance sensor node must have signal compression, feature extraction, target localization, noise cancellation and collaborative signal processing with low computation and communication energy dissipation. In this paper, we introduce an algorithm for light-weight wireless sensor node signal processing based on lifting scheme wavelet analysis feature extraction in distributed sensor network.

Compositional Stability of the Bacterial Community in a Climate-Sensitive Sub-Arctic Peatland.

PubMed

Weedon, James T; Kowalchuk, George A; Aerts, Rien; Freriks, Stef; Röling, Wilfred F M; van Bodegom, Peter M

2017-01-01

The climate sensitivity of microbe-mediated soil processes such as carbon and nitrogen cycling offers an interesting case for evaluating the corresponding sensitivity of microbial community composition to environmental change. Better understanding of the degree of linkage between functional and compositional stability would contribute to ongoing efforts to build mechanistic models aiming at predicting rates of microbe-mediated processes. We used an amplicon sequencing approach to test if previously observed large effects of experimental soil warming on C and N cycle fluxes (50-100% increases) in a sub-arctic Sphagnum peatland were reflected in changes in the composition of the soil bacterial community. We found that treatments that previously induced changes to fluxes did not associate with changes in the phylogenetic composition of the soil bacterial community. For both DNA- and RNA-based analyses, variation in bacterial communities could be explained by the hierarchy: spatial variation (12-15% of variance explained) > temporal variation (7-11%) > climate treatment (4-9%). We conclude that the bacterial community in this environment is stable under changing conditions, despite the previously observed sensitivity of process rates-evidence that microbe-mediated soil processes can alter without concomitant changes in bacterial communities. We propose that progress in linking soil microbial communities to ecosystem processes can be advanced by further investigating the relative importance of community composition effects versus physico-chemical factors in controlling biogeochemical process rates in different contexts.

Examining Electronic Learning Communities through the Communities of Practice Framework

ERIC Educational Resources Information Center

Linton, Jayme N.

2015-01-01

This qualitative interpretive case study used Wenger's (1998) communities of practice (CoP) framework to analyze how the electronic learning community (eLC) process at an established state virtual high school operated like a community of practice. Components of the eLC process were analyzed according to elements of the CoP framework, which…

Optical signal processing techniques and applications of optical phase modulation in high-speed communication systems

NASA Astrophysics Data System (ADS)

Deng, Ning

In recent years, optical phase modulation has attracted much research attention in the field of fiber optic communications. Compared with the traditional optical intensity-modulated signal, one of the main merits of the optical phase-modulated signal is the better transmission performance. For optical phase modulation, in spite of the comprehensive study of its transmission performance, only a little research has been carried out in terms of its functions, applications and signal processing for future optical networks. These issues are systematically investigated in this thesis. The research findings suggest that optical phase modulation and its signal processing can greatly facilitate flexible network functions and high bandwidth which can be enjoyed by end users. In the thesis, the most important physical-layer technology, signal processing and multiplexing, are investigated with optical phase-modulated signals. Novel and advantageous signal processing and multiplexing approaches are proposed and studied. Experimental investigations are also reported and discussed in the thesis. Optical time-division multiplexing and demultiplexing. With the ever-increasing demand on communication bandwidth, optical time division multiplexing (OTDM) is an effective approach to upgrade the capacity of each wavelength channel in current optical systems. OTDM multiplexing can be simply realized, however, the demultiplexing requires relatively complicated signal processing and stringent timing control, and thus hinders its practicability. To tackle this problem, in this thesis a new OTDM scheme with hybrid DPSK and OOK signals is proposed. Experimental investigation shows this scheme can greatly enhance the demultiplexing timing misalignment and improve the demultiplexing performance, and thus make OTDM more practical and cost effective. All-optical signal processing. In current and future optical communication systems and networks, the data rate per wavelength has been approaching the speed limitation of electronics. Thus, all-optical signal processing techniques are highly desirable to support the necessary optical switching functionalities in future ultrahigh-speed optical packet-switching networks. To cope with the wide use of optical phase-modulated signals, in the thesis, an all-optical logic for DPSK or PSK input signals is developed, for the first time. Based on four-wave mixing in semiconductor optical amplifier, the structure of the logic gate is simple, compact, and capable of supporting ultrafast operation. In addition to the general logic processing, a simple label recognition scheme, as a specific signal processing function, is proposed for phase-modulated label signals. The proposed scheme can recognize any incoming label pattern according to the local pattern, and is potentially capable of handling variable-length label patterns. Optical access network with multicast overlay and centralized light sources. In the arena of optical access networks, wavelength division multiplexing passive optical network (WDM-PON) is a promising technology to deliver high-speed data traffic. However, most of proposed WDM-PONs only support conventional point-to-point service, and cannot meet the requirement of increasing demand on broadcast and multicast service. In this thesis, a simple network upgrade is proposed based on the traditional PON architecture to support both point-to-point and multicast service. In addition, the two service signals are modulated on the same lightwave carrier. The upstream signal is also remodulated on the same carrier at the optical network unit, which can significantly relax the requirement on wavelength management at the network unit.

GNSS Radio Occultation Observations as a data source for Ionospheric Assimilation: COSMIC-1 & COSMIC-2

NASA Astrophysics Data System (ADS)

Yue, X.; Schreiner, W. S.; Kuo, Y. H.

2014-12-01

Since the pioneer GPS/MET mission, low Earth orbit (LEO) based global navigation satellite system (GNSS) Radio Occultation (RO) technique has been a powerful technique in ionosphere monitoring. After that, many LEO satellites were launched with RO payload, include: CHAMP , GRACE, SAC-C/D, COSMIC, C/NOFS, Metop-A/B, TerraSAR-X/TanDEM-X, and etc. COSMIC was the first constellation of satellites dedicated primarily to RO and delivering RO data in near real time. Currently in UCAR CDAAC, we process most of these missions' RO data for the community. Due to the success of COSMIC mission, a follow on mission called COSMIC-2 will be launched in 2016 and 2018, respectively. The COSMIC-2 RO data will be 4-6 times of COSMIC due to the doubled satellite and GNSS signals. In this paper we will describe: (1) Data process and quality in UCAR/CDAAC; (2) Ionospheric data assimilation results based on COSMIC data; (3) OSSE study for COSMIC-2.

An international network of magnetic observatories

USGS Publications Warehouse

Love, Jeffrey J.; Chulliat, A.

2013-01-01

Since its formation in the late 1980s, the International Real-Time Magnetic Observatory Network (INTERMAGNET), a voluntary consortium of geophysical institutes from around the world, has promoted the operation of magnetic observatories according to modern standards [eg. Rasson, 2007]. INTERMAGNET institutes have cooperatively developed infrastructure for data exchange and management ads well as methods for data processing and checking. INTERMAGNET institute have also helped to expand global geomagnetic monitoring capacity, most notably by assisting magnetic observatory institutes in economically developing countries by working directly with local geophysicists. Today the INTERMAGNET consortium encompasses 57 institutes from 40 countries supporting 120 observatories (see Figures 1a and 1b). INTERMAGNET data record a wide variety of time series signals related to a host of different physical processes in the Earth's interiors and in the Earth's surrounding space environment [e.g., Love, 2008]. Observatory data have always had a diverse user community, and to meet evolving demand, INTERMAGNET has recently coordinated the introduction of several new data services.

Calibration of an electronic nose for poultry farm

NASA Astrophysics Data System (ADS)

Abdullah, A. H.; Shukor, S. A.; Kamis, M. S.; Shakaff, A. Y. M.; Zakaria, A.; Rahim, N. A.; Mamduh, S. M.; Kamarudin, K.; Saad, F. S. A.; Masnan, M. J.; Mustafa, H.

2017-03-01

Malodour from the poultry farms could cause air pollution and therefore potentially dangerous to humans' and animals' health. This issue also poses sustainability risk to the poultry industries due to objections from local community. The aim of this paper is to develop and calibrate a cost effective and efficient electronic nose for poultry farm air monitoring. The instrument main components include sensor chamber, array of specific sensors, microcontroller, signal conditioning circuits and wireless sensor networks. The instrument was calibrated to allow classification of different concentrations of main volatile compounds in the poultry farm malodour. The outcome of the process will also confirm the device's reliability prior to being used for poultry farm malodour assessment. The Multivariate Analysis (HCA and KNN) and Artificial Neural Network (ANN) pattern recognition technique was used to process the acquired data. The results show that the instrument is able to calibrate the samples using ANN classification model with high accuracy. The finding verifies the instrument's performance to be used as an effective poultry farm malodour monitoring.

High performance hybrid functional Petri net simulations of biological pathway models on CUDA.

PubMed

Chalkidis, Georgios; Nagasaki, Masao; Miyano, Satoru

2011-01-01

Hybrid functional Petri nets are a wide-spread tool for representing and simulating biological models. Due to their potential of providing virtual drug testing environments, biological simulations have a growing impact on pharmaceutical research. Continuous research advancements in biology and medicine lead to exponentially increasing simulation times, thus raising the demand for performance accelerations by efficient and inexpensive parallel computation solutions. Recent developments in the field of general-purpose computation on graphics processing units (GPGPU) enabled the scientific community to port a variety of compute intensive algorithms onto the graphics processing unit (GPU). This work presents the first scheme for mapping biological hybrid functional Petri net models, which can handle both discrete and continuous entities, onto compute unified device architecture (CUDA) enabled GPUs. GPU accelerated simulations are observed to run up to 18 times faster than sequential implementations. Simulating the cell boundary formation by Delta-Notch signaling on a CUDA enabled GPU results in a speedup of approximately 7x for a model containing 1,600 cells.

Bacterial pathogenesis of plants: future challenges from a microbial perspective: Challenges in Bacterial Molecular Plant Pathology.

PubMed

Pfeilmeier, Sebastian; Caly, Delphine L; Malone, Jacob G

2016-10-01

Plant infection is a complicated process. On encountering a plant, pathogenic microorganisms must first adapt to life on the epiphytic surface, and survive long enough to initiate an infection. Responsiveness to the environment is critical throughout infection, with intracellular and community-level signal transduction pathways integrating environmental signals and triggering appropriate responses in the bacterial population. Ultimately, phytopathogens must migrate from the epiphytic surface into the plant tissue using motility and chemotaxis pathways. This migration is coupled with overcoming the physical and chemical barriers to entry into the plant apoplast. Once inside the plant, bacteria use an array of secretion systems to release phytotoxins and protein effectors that fulfil diverse pathogenic functions (Fig. ) (Melotto and Kunkel, ; Phan Tran et al., ). As our understanding of the pathways and mechanisms underpinning plant pathogenicity increases, a number of central research challenges are emerging that will profoundly shape the direction of research in the future. We need to understand the bacterial phenotypes that promote epiphytic survival and surface adaptation in pathogenic bacteria. How do these pathways function in the context of the plant-associated microbiome, and what impact does this complex microbial community have on the onset and severity of plant infections? The huge importance of bacterial signal transduction to every stage of plant infection is becoming increasingly clear. However, there is a great deal to learn about how these signalling pathways function in phytopathogenic bacteria, and the contribution they make to various aspects of plant pathogenicity. We are increasingly able to explore the structural and functional diversity of small-molecule natural products from plant pathogens. We need to acquire a much better understanding of the production, deployment, functional redundancy and physiological roles of these molecules. Type III secretion systems (T3SSs) are important and well-studied contributors to bacterial disease. Several key unanswered questions will shape future investigations of these systems. We need to define the mechanism of hierarchical and temporal control of effector secretion. For successful infection, effectors need to interact with host components to exert their function. Advanced biochemical, proteomic and cell biological techniques will enable us to study the function of effectors inside the host cell in more detail and on a broader scale. Population genomics analyses provide insight into evolutionary adaptation processes of phytopathogens. The determination of the diversity and distribution of type III effectors (T3Es) and other virulence genes within and across pathogenic species, pathovars and strains will allow us to understand how pathogens adapt to specific hosts, the evolutionary pathways available to them, and the possible future directions of the evolutionary arms race between effectors and molecular plant targets. Although pathogenic bacteria employ a host of different virulence and proliferation strategies, as a result of the space constraints, this review focuses mainly on the hemibiotrophic pathogens. We discuss the process of plant infection from the perspective of these important phytopathogens, and highlight new approaches to address the outstanding challenges in this important and fast-moving field. © 2016 The Authors. Molecular Plant Pathology Published by British Society for Plant Pathology and John Wiley & Sons Ltd.

Methods for Linking Community Views to Measureable Outcomes in a Youth Violence Prevention Program

PubMed Central

McDonald, Catherine C.; Richmond, Therese S.; Guerra, Terry; Thomas, Nicole A.; Walker, Alia; Branas, Charles C.; TenHave, Thomas R.; Vaughn, Nicole A.; Leff, Stephen S.; Hausman, Alice J.

2013-01-01

Background All parties in community–academic partnerships have a vested interest prevention program success. Markers of success that reflect community’s experiences of programmatic prevention success are not always measurable, but critically speak to community-defined needs. Objective The purpose of this manuscript was to (1) describe our systematic process for linking locally relevant community views (community-defined indicators) to measurable outcomes in the context of a youth violence prevention program and (2) discuss lessons learned, next steps, and recommendations for others trying to replicate a similar process. Methods A research team composed of both academic and community researchers conducted a systematic process of matching community-defined indicators of youth violence prevention programmatic success to standardized youth survey items being administered in the course of a program evaluation. The research team of three community partners and Five academic partners considered 43 community-defined indicators and 208 items from the youth surveys being utilized within the context of a community-based aggression prevention program. At the end of the matching process, 92 youth survey items were identified and agreed upon as potential matches to 11 of the community-defined indicators. Conclusions We applied rigorous action steps to match community-defined indicators to survey data collected in the youth violence prevention intervention. We learned important lessons that inform recommendations for others interested in such endeavors. The process used to derive and assess community-defined indicators of success emphasized the principles of community-based participatory research (CBPR) and use of existing and available data to reduce participant burden. PMID:23221296

Functional description of signal processing in the Rogue GPS receiver

NASA Technical Reports Server (NTRS)

Thomas, J. B.

1988-01-01

Over the past year, two Rogue GPS prototype receivers have been assembled and successfully subjected to a variety of laboratory and field tests. A functional description is presented of signal processing in the Rogue receiver, tracing the signal from RF input to the output values of group delay, phase, and data bits. The receiver can track up to eight satellites, without time multiplexing among satellites or channels, simultaneously measuring both group delay and phase for each of three channels (L1-C/A, L1-P, L2-P). The Rogue signal processing described requires generation of the code for all three channels. Receiver functional design, which emphasized accuracy, reliability, flexibility, and dynamic capability, is summarized. A detailed functional description of signal processing is presented, including C/A-channel and P-channel processing, carrier-aided averaging of group delays, checks for cycle slips, acquistion, and distinctive features.

Optical Signal Processing: Poisson Image Restoration and Shearing Interferometry

NASA Technical Reports Server (NTRS)

Hong, Yie-Ming

1973-01-01

Optical signal processing can be performed in either digital or analog systems. Digital computers and coherent optical systems are discussed as they are used in optical signal processing. Topics include: image restoration; phase-object visualization; image contrast reversal; optical computation; image multiplexing; and fabrication of spatial filters. Digital optical data processing deals with restoration of images degraded by signal-dependent noise. When the input data of an image restoration system are the numbers of photoelectrons received from various areas of a photosensitive surface, the data are Poisson distributed with mean values proportional to the illuminance of the incoherently radiating object and background light. Optical signal processing using coherent optical systems is also discussed. Following a brief review of the pertinent details of Ronchi's diffraction grating interferometer, moire effect, carrier-frequency photography, and achromatic holography, two new shearing interferometers based on them are presented. Both interferometers can produce variable shear.

Software for biomedical engineering signal processing laboratory experiments.

PubMed

Tompkins, Willis J; Wilson, J

2009-01-01

In the early 1990's we developed a special computer program called UW DigiScope to provide a mechanism for anyone interested in biomedical digital signal processing to study the field without requiring any other instrument except a personal computer. There are many digital filtering and pattern recognition algorithms used in processing biomedical signals. In general, students have very limited opportunity to have hands-on access to the mechanisms of digital signal processing. In a typical course, the filters are designed non-interactively, which does not provide the student with significant understanding of the design constraints of such filters nor their actual performance characteristics. UW DigiScope 3.0 is the first major update since version 2.0 was released in 1994. This paper provides details on how the new version based on MATLAB! works with signals, including the filter design tool that is the programming interface between UW DigiScope and processing algorithms.

Empowering community settings: agents of individual development, community betterment, and positive social change.

PubMed

Maton, Kenneth I

2008-03-01

The pathways and processes through which empowering community settings influence their members, the surrounding community and the larger society are examined. To generate the proposed pathways and processes, a broad range of studies of community settings were reviewed, in the domains of adult well-being, positive youth development, locality development, and social change. A set of organizational characteristics and associated processes leading to member empowerment across domains were identified, as well as three pathways through which empowering settings in each domain contribute to community betterment and positive social change. The paper concludes with an examination of the ways that community psychology and allied disciplines can help increase the number and range of empowering settings, and enhance the community and societal impact of existing ones.

Signal processing for order 10 pm accuracy displacement metrology in real-world scientific applications

NASA Technical Reports Server (NTRS)

Halverson, Peter G.; Loya, Frank M.

2004-01-01

This paper describes heterodyne displacement metrology gauge signal processing methods that achieve satisfactory robustness against low signal strength and spurious signals, and good long-term stability. We have a proven displacement-measuring approach that is useful not only to space-optical projects at JPL, but also to the wider field of distance measurements.

Fast and economic signal processing technique of laser diode self-mixing interferometry for nanoparticle size measurement

NASA Astrophysics Data System (ADS)

Wang, Huarui; Shen, Jianqi

2014-05-01

The size of nanoparticles is measured by laser diode self-mixing interferometry, which employs a sensitive, compact, and simple optical setup. However, the signal processing of the interferometry is slow or expensive. In this article, a fast and economic signal processing technique is introduced, in which the self-mixing AC signal is transformed into DC signals with an analog circuit consisting of 16 channels. These DC signals are obtained as a spectrum from which the size of nanoparticles can be retrieved. The technique is examined by measuring the standard nanoparticles. Further experiments are performed to compare the skimmed milk and whole milk, and also the fresh skimmed milk and rotten skimmed milk.

Reconfigurable environmentally adaptive computing

NASA Technical Reports Server (NTRS)

Coxe, Robin L. (Inventor); Galica, Gary E. (Inventor)

2008-01-01

Described are methods and apparatus, including computer program products, for reconfigurable environmentally adaptive computing technology. An environmental signal representative of an external environmental condition is received. A processing configuration is automatically selected, based on the environmental signal, from a plurality of processing configurations. A reconfigurable processing element is reconfigured to operate according to the selected processing configuration. In some examples, the environmental condition is detected and the environmental signal is generated based on the detected condition.

Gastropod diversification and community structuring processes in ancient Lake Ohrid: a metacommunity speciation perspective

NASA Astrophysics Data System (ADS)

Hauffe, T.; Albrecht, C.; Wilke, T.

2015-09-01

The Balkan Lake Ohrid is the oldest and most speciose freshwater lacustrine system in Europe. However, it remains unclear whether the diversification of its endemic taxa is mainly driven by neutral processes, environmental factors, or species interactions. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics. Such a unifying framework - the metacommunity speciation model - considers how community assembly affects diversification and vice versa by assessing the relative contribution of the three main community assembly processes, dispersal limitation, environmental filtering, and species interaction. The current study therefore used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process based metacommunity analyses. Specifically, the study aimed at (i) identifying the relative importance of the three community assembly processes and (ii) to test whether the importance of these individual processes changes gradually with lake depth or whether they are distinctively related to eco-zones. Based on specific simulation steps for each of the three processes, it could be demonstrated that dispersal limitation had the strongest influence on gastropod community structures in Lake Ohrid. However, it was not the exclusive assembly process but acted together with the other two processes - environmental filtering, and species interaction. In fact, the relative importance of the three community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter. The study thus corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community structure) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental filtering and biotic interaction also suggests a small but significant influence of ecological speciation. These findings contribute to the main goal of the SCOPSCO initiative - inferring the drivers of biotic evolution - and might provide an integrative perspective on biological and limnological dynamics in ancient Lake Ohrid.

The Vector, Signal, and Image Processing Library (VSIPL): an Open Standard for Astronomical Data Processing

NASA Astrophysics Data System (ADS)

Kepner, J. V.; Janka, R. S.; Lebak, J.; Richards, M. A.

1999-12-01

The Vector/Signal/Image Processing Library (VSIPL) is a DARPA initiated effort made up of industry, government and academic representatives who have defined an industry standard API for vector, signal, and image processing primitives for real-time signal processing on high performance systems. VSIPL supports a wide range of data types (int, float, complex, ...) and layouts (vectors, matrices and tensors) and is ideal for astronomical data processing. The VSIPL API is intended to serve as an open, vendor-neutral, industry standard interface. The object-based VSIPL API abstracts the memory architecture of the underlying machine by using the concept of memory blocks and views. Early experiments with VSIPL code conversions have been carried out by the High Performance Computing Program team at the UCSD. Commercially, several major vendors of signal processors are actively developing implementations. VSIPL has also been explicitly required as part of a recent Rome Labs teraflop procurement. This poster presents the VSIPL API, its functionality and the status of various implementations.

Hardware design and implementation of fast DOA estimation method based on multicore DSP

NASA Astrophysics Data System (ADS)

Guo, Rui; Zhao, Yingxiao; Zhang, Yue; Lin, Qianqiang; Chen, Zengping

2016-10-01

In this paper, we present a high-speed real-time signal processing hardware platform based on multicore digital signal processor (DSP). The real-time signal processing platform shows several excellent characteristics including high performance computing, low power consumption, large-capacity data storage and high speed data transmission, which make it able to meet the constraint of real-time direction of arrival (DOA) estimation. To reduce the high computational complexity of DOA estimation algorithm, a novel real-valued MUSIC estimator is used. The algorithm is decomposed into several independent steps and the time consumption of each step is counted. Based on the statistics of the time consumption, we present a new parallel processing strategy to distribute the task of DOA estimation to different cores of the real-time signal processing hardware platform. Experimental results demonstrate that the high processing capability of the signal processing platform meets the constraint of real-time direction of arrival (DOA) estimation.

The Not-So-Global Blood Oxygen Level-Dependent Signal.

PubMed

Billings, Jacob; Keilholz, Shella

2018-04-01

Global signal regression is a controversial processing step for resting-state functional magnetic resonance imaging, partly because the source of the global blood oxygen level-dependent (BOLD) signal remains unclear. On the one hand, nuisance factors such as motion can readily introduce coherent BOLD changes across the whole brain. On the other hand, the global signal has been linked to neural activity and vigilance levels, suggesting that it contains important neurophysiological information and should not be discarded. Any widespread pattern of coordinated activity is likely to contribute appreciably to the global signal. Such patterns may include large-scale quasiperiodic spatiotemporal patterns, known also to be tied to performance on vigilance tasks. This uncertainty surrounding the separability of the global BOLD signal from concurrent neurological processes motivated an examination of the global BOLD signal's spatial distribution. The results clarify that although the global signal collects information from all tissue classes, a diverse subset of the BOLD signal's independent components contribute the most to the global signal. Further, the timing of each network's contribution to the global signal is not consistent across volunteers, confirming the independence of a constituent process that comprises the global signal.

Signal Processing, Analysis, & Display

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lager, Darrell; Azevado, Stephen

1986-06-01

SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time- and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG - a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time- and frequency-domain signalsmore » including operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments,commenting lines, defining commands, and automatic execution for each item in a repeat sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.« less

SIG. Signal Processing, Analysis, & Display

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernandez, J.; Lager, D.; Azevedo, S.

1992-01-22

SIG is a general-purpose signal processing, analysis, and display program. Its main purpose is to perform manipulations on time- and frequency-domain signals. However, it has been designed to ultimately accommodate other representations for data such as multiplexed signals and complex matrices. Two user interfaces are provided in SIG - a menu mode for the unfamiliar user and a command mode for more experienced users. In both modes errors are detected as early as possible and are indicated by friendly, meaningful messages. An on-line HELP package is also included. A variety of operations can be performed on time- and frequency-domain signalsmore » including operations on the samples of a signal, operations on the entire signal, and operations on two or more signals. Signal processing operations that can be performed are digital filtering (median, Bessel, Butterworth, and Chebychev), ensemble average, resample, auto and cross spectral density, transfer function and impulse response, trend removal, convolution, Fourier transform and inverse window functions (Hamming, Kaiser-Bessel), simulation (ramp, sine, pulsetrain, random), and read/write signals. User definable signal processing algorithms are also featured. SIG has many options including multiple commands per line, command files with arguments,commenting lines, defining commands, and automatic execution for each item in a repeat sequence. Graphical operations on signals and spectra include: x-y plots of time signals; real, imaginary, magnitude, and phase plots of spectra; scaling of spectra for continuous or discrete domain; cursor zoom; families of curves; and multiple viewports.« less

Are Big Food's corporate social responsibility strategies valuable to communities? A qualitative study with parents and children.

PubMed

Richards, Zoe; Phillipson, Lyn

2017-12-01

Recent studies have identified parents and children as two target groups whom Big Food hopes to positively influence through its corporate social responsibility (CSR) strategies. The current preliminary study aimed to gain an in-depth understanding of parents and children's awareness and interpretation of Big Food's CSR strategies to understand how CSR shapes their beliefs about companies. Community-based qualitative semi-structured interviews. New South Wales, Australia. Parents (n 15) and children aged 8-12 years (n 15). Parents and children showed unprompted recognition of CSR activities when shown McDonald's and Coca-Cola brand logos, indicating a strong level of association between the brands and activities that target the settings of children. When discussing CSR strategies some parents and most children saw value in the activities, viewing them as acts of merit or worth. For some parents and children, the companies' CSR activities were seen as a reflection of the company's moral attributes, which resonated with their own values of charity and health. For others, CSR strategies were in conflict with companies' core business. Finally, some also viewed the activities as harmful, representing a deceit of the public and a smokescreen for the companies' ultimately unethical behaviour. A large proportion of participants valued the CSR activities, signalling that denormalising CSR to sever the strong ties between the community and Big Food will be a difficult process for the public health community. Efforts to gain public acceptance for action on CSR may need greater levels of persuasion to gain public support of a comprehensive and restrictive approach.

Hybrid Analog/Digital Receiver

NASA Technical Reports Server (NTRS)

Brown, D. H.; Hurd, W. J.

1989-01-01

Advanced hybrid analog/digital receiver processes intermediate-frequency (IF) signals carrying digital data in form of phase modulation. Uses IF sampling and digital phase-locked loops to track carrier and subcarrier signals and to synchronize data symbols. Consists of three modules: IF assembly, signal-processing assembly, and test-signal assembly. Intended for use in Deep Space Network, but presumably basic design modified for such terrestrial uses as communications or laboratory instrumentation where signals weak and/or noise strong.

Receptor signaling clusters in the immune synapse(in eng)

DOE PAGES

Dustin, Michael L.; Groves, Jay T.

2012-02-23

Signaling processes between various immune cells involve large-scale spatial reorganization of receptors and signaling molecules within the cell-cell junction. These structures, now collectively referred to as immune synapses, interleave physical and mechanical processes with the cascades of chemical reactions that constitute signal transduction systems. Molecular level clustering, spatial exclusion, and long-range directed transport are all emerging as key regulatory mechanisms. The study of these processes is drawing researchers from physical sciences to join the effort and represents a rapidly growing branch of biophysical chemistry. Furthermore, recent advances in physical and quantitative analyses of signaling within the immune synapses are reviewedmore » here.« less

Receptor signaling clusters in the immune synapse (in eng)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dustin, Michael L.; Groves, Jay T.

2012-02-23

Signaling processes between various immune cells involve large-scale spatial reorganization of receptors and signaling molecules within the cell-cell junction. These structures, now collectively referred to as immune synapses, interleave physical and mechanical processes with the cascades of chemical reactions that constitute signal transduction systems. Molecular level clustering, spatial exclusion, and long-range directed transport are all emerging as key regulatory mechanisms. The study of these processes is drawing researchers from physical sciences to join the effort and represents a rapidly growing branch of biophysical chemistry. Furthermore, recent advances in physical and quantitative analyses of signaling within the immune synapses are reviewedmore » here.« less

Plant community succession in modern Yellow River Delta, China*

PubMed Central

Zhang, Gao-sheng; Wang, Ren-qing; Song, Bai-min

2007-01-01

Data were collected in different successional stages using a simultaneous sampling method and analyzed through quantitative classification method. Three large groups and 12 classes were made to represent the community patterns of three succession stages and 12 succession communities. The succession series of plant community in the study area was as follows: saline bare land→community Suaeda salsa→community Tamarix chinensis→grassland. Succession degree and succession process of 12 succession communities were calculated. Most of these communities were in the lower succession stage, however, community Phragmites communis+Glycine soja and community Imperata cylindrica+G. soja were close to the succession stage of grassland climax. Five species diversity indices were used to study the changes in species richness, species evenness and diversity during succession of community. Heterogeneity index and richness index increased gradually during the community succession process, but species evenness tended to decrease with succession development. The relation between succession and environment was studied by ordination technique, and the results showed that the soil salt content was an important factor to halarch succession of the modern Yellow River Delta. It affected community structure, species composition and succession process. PMID:17657854

High taxonomic variability despite stable functional structure across microbial communities.

PubMed

Louca, Stilianos; Jacques, Saulo M S; Pires, Aliny P F; Leal, Juliana S; Srivastava, Diane S; Parfrey, Laura Wegener; Farjalla, Vinicius F; Doebeli, Michael

2016-12-05

Understanding the processes that are driving variation of natural microbial communities across space or time is a major challenge for ecologists. Environmental conditions strongly shape the metabolic function of microbial communities; however, other processes such as biotic interactions, random demographic drift or dispersal limitation may also influence community dynamics. The relative importance of these processes and their effects on community function remain largely unknown. To address this uncertainty, here we examined bacterial and archaeal communities in replicate 'miniature' aquatic ecosystems contained within the foliage of wild bromeliads. We used marker gene sequencing to infer the taxonomic composition within nine metabolic functional groups, and shotgun environmental DNA sequencing to estimate the relative abundances of these groups. We found that all of the bromeliads exhibited remarkably similar functional community structures, but that the taxonomic composition within individual functional groups was highly variable. Furthermore, using statistical analyses, we found that non-neutral processes, including environmental filtering and potentially biotic interactions, at least partly shaped the composition within functional groups and were more important than spatial dispersal limitation and demographic drift. Hence both the functional structure and taxonomic composition within functional groups of natural microbial communities may be shaped by non-neutral and roughly separate processes.

A user's guide for the signal processing software for image and speech compression developed in the Communications and Signal Processing Laboratory (CSPL), version 1

NASA Technical Reports Server (NTRS)

Kumar, P.; Lin, F. Y.; Vaishampayan, V.; Farvardin, N.

1986-01-01

A complete documentation of the software developed in the Communication and Signal Processing Laboratory (CSPL) during the period of July 1985 to March 1986 is provided. Utility programs and subroutines that were developed for a user-friendly image and speech processing environment are described. Additional programs for data compression of image and speech type signals are included. Also, programs for the zero-memory and block transform quantization in the presence of channel noise are described. Finally, several routines for simulating the perfromance of image compression algorithms are included.

Preliminary development of digital signal processing in microwave radiometers

NASA Technical Reports Server (NTRS)

Stanley, W. D.

1980-01-01

Topics covered involve a number of closely related tasks including: the development of several control loop and dynamic noise model computer programs for simulating microwave radiometer measurements; computer modeling of an existing stepped frequency radiometer in an effort to determine its optimum operational characteristics; investigation of the classical second order analog control loop to determine its ability to reduce the estimation error in a microwave radiometer; investigation of several digital signal processing unit designs; initiation of efforts to develop required hardware and software for implementation of the digital signal processing unit; and investigation of the general characteristics and peculiarities of digital processing noiselike microwave radiometer signals.

A systematic strategic planning process focused on improved community engagement by an academic health center: the University of Kansas Medical Center's story.

PubMed

Cook, David C; Nelson, Eve-Lynn; Ast, Cori; Lillis, Teresa

2013-05-01

A growing number of academic health centers (AHCs) are considering approaches to expand collaboration with their communities in order to address complex and multisystem health concerns. In 2010, internal leaders at the University of Kansas Medical Center undertook a strategic planning process to enhance both community engagement activities and the scholarship resulting from these engagement activities. The authors describe the strategic planning process, recommendations, and actions associated with elevating community engagement within the AHC's mission and priorities. The strategic planning process included conducting an inventory of community engagement activities within the AHC; analyzing strengths, weaknesses, opportunities, and threats for community engagement work; and identifying goals and strategies to improve future community engagement activities and scholarship. The resulting road map for enhancing community engagement at their institution through 2015 consists of four main strategies: emphasize scholarship in community engagement, revise organizational structures to better facilitate community engagement, prioritize current engagement activities to ensure appropriate use of resources, and enhance communication of engagement initiatives to further develop stakeholder relationships.The authors also discuss implementation of the plan to date and highlight lessons learned that may inform other AHCs as they enhance and expand similar endeavors.

EEG Recording and Online Signal Processing on Android: A Multiapp Framework for Brain-Computer Interfaces on Smartphone

PubMed Central

Debener, Stefan; Emkes, Reiner; Volkening, Nils; Fudickar, Sebastian; Bleichner, Martin G.

2017-01-01

Objective Our aim was the development and validation of a modular signal processing and classification application enabling online electroencephalography (EEG) signal processing on off-the-shelf mobile Android devices. The software application SCALA (Signal ProCessing and CLassification on Android) supports a standardized communication interface to exchange information with external software and hardware. Approach In order to implement a closed-loop brain-computer interface (BCI) on the smartphone, we used a multiapp framework, which integrates applications for stimulus presentation, data acquisition, data processing, classification, and delivery of feedback to the user. Main Results We have implemented the open source signal processing application SCALA. We present timing test results supporting sufficient temporal precision of audio events. We also validate SCALA with a well-established auditory selective attention paradigm and report above chance level classification results for all participants. Regarding the 24-channel EEG signal quality, evaluation results confirm typical sound onset auditory evoked potentials as well as cognitive event-related potentials that differentiate between correct and incorrect task performance feedback. Significance We present a fully smartphone-operated, modular closed-loop BCI system that can be combined with different EEG amplifiers and can easily implement other paradigms. PMID:29349070

EEG Recording and Online Signal Processing on Android: A Multiapp Framework for Brain-Computer Interfaces on Smartphone.

PubMed

Blum, Sarah; Debener, Stefan; Emkes, Reiner; Volkening, Nils; Fudickar, Sebastian; Bleichner, Martin G

2017-01-01

Our aim was the development and validation of a modular signal processing and classification application enabling online electroencephalography (EEG) signal processing on off-the-shelf mobile Android devices. The software application SCALA (Signal ProCessing and CLassification on Android) supports a standardized communication interface to exchange information with external software and hardware. In order to implement a closed-loop brain-computer interface (BCI) on the smartphone, we used a multiapp framework, which integrates applications for stimulus presentation, data acquisition, data processing, classification, and delivery of feedback to the user. We have implemented the open source signal processing application SCALA. We present timing test results supporting sufficient temporal precision of audio events. We also validate SCALA with a well-established auditory selective attention paradigm and report above chance level classification results for all participants. Regarding the 24-channel EEG signal quality, evaluation results confirm typical sound onset auditory evoked potentials as well as cognitive event-related potentials that differentiate between correct and incorrect task performance feedback. We present a fully smartphone-operated, modular closed-loop BCI system that can be combined with different EEG amplifiers and can easily implement other paradigms.

Fast, multi-channel real-time processing of signals with microsecond latency using graphics processing units.

PubMed

Rath, N; Kato, S; Levesque, J P; Mauel, M E; Navratil, G A; Peng, Q

2014-04-01

Fast, digital signal processing (DSP) has many applications. Typical hardware options for performing DSP are field-programmable gate arrays (FPGAs), application-specific integrated DSP chips, or general purpose personal computer systems. This paper presents a novel DSP platform that has been developed for feedback control on the HBT-EP tokamak device. The system runs all signal processing exclusively on a Graphics Processing Unit (GPU) to achieve real-time performance with latencies below 8 μs. Signals are transferred into and out of the GPU using PCI Express peer-to-peer direct-memory-access transfers without involvement of the central processing unit or host memory. Tests were performed on the feedback control system of the HBT-EP tokamak using forty 16-bit floating point inputs and outputs each and a sampling rate of up to 250 kHz. Signals were digitized by a D-TACQ ACQ196 module, processing done on an NVIDIA GTX 580 GPU programmed in CUDA, and analog output was generated by D-TACQ AO32CPCI modules.

Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?

PubMed Central

Graham, Emily B.; Knelman, Joseph E.; Schindlbacher, Andreas; Siciliano, Steven; Breulmann, Marc; Yannarell, Anthony; Beman, J. M.; Abell, Guy; Philippot, Laurent; Prosser, James; Foulquier, Arnaud; Yuste, Jorge C.; Glanville, Helen C.; Jones, Davey L.; Angel, Roey; Salminen, Janne; Newton, Ryan J.; Bürgmann, Helmut; Ingram, Lachlan J.; Hamer, Ute; Siljanen, Henri M. P.; Peltoniemi, Krista; Potthast, Karin; Bañeras, Lluís; Hartmann, Martin; Banerjee, Samiran; Yu, Ri-Qing; Nogaro, Geraldine; Richter, Andreas; Koranda, Marianne; Castle, Sarah C.; Goberna, Marta; Song, Bongkeun; Chatterjee, Amitava; Nunes, Olga C.; Lopes, Ana R.; Cao, Yiping; Kaisermann, Aurore; Hallin, Sara; Strickland, Michael S.; Garcia-Pausas, Jordi; Barba, Josep; Kang, Hojeong; Isobe, Kazuo; Papaspyrou, Sokratis; Pastorelli, Roberta; Lagomarsino, Alessandra; Lindström, Eva S.; Basiliko, Nathan; Nemergut, Diana R.

2016-01-01

Microorganisms are vital in mediating the earth’s biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: ‘When do we need to understand microbial community structure to accurately predict function?’ We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology. PMID:26941732

Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?

PubMed

Graham, Emily B; Knelman, Joseph E; Schindlbacher, Andreas; Siciliano, Steven; Breulmann, Marc; Yannarell, Anthony; Beman, J M; Abell, Guy; Philippot, Laurent; Prosser, James; Foulquier, Arnaud; Yuste, Jorge C; Glanville, Helen C; Jones, Davey L; Angel, Roey; Salminen, Janne; Newton, Ryan J; Bürgmann, Helmut; Ingram, Lachlan J; Hamer, Ute; Siljanen, Henri M P; Peltoniemi, Krista; Potthast, Karin; Bañeras, Lluís; Hartmann, Martin; Banerjee, Samiran; Yu, Ri-Qing; Nogaro, Geraldine; Richter, Andreas; Koranda, Marianne; Castle, Sarah C; Goberna, Marta; Song, Bongkeun; Chatterjee, Amitava; Nunes, Olga C; Lopes, Ana R; Cao, Yiping; Kaisermann, Aurore; Hallin, Sara; Strickland, Michael S; Garcia-Pausas, Jordi; Barba, Josep; Kang, Hojeong; Isobe, Kazuo; Papaspyrou, Sokratis; Pastorelli, Roberta; Lagomarsino, Alessandra; Lindström, Eva S; Basiliko, Nathan; Nemergut, Diana R

2016-01-01

Microorganisms are vital in mediating the earth's biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: 'When do we need to understand microbial community structure to accurately predict function?' We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology.

Method and apparatus for improving resolution in spectrometers processing output steps from non-ideal signal sources

DOEpatents

Warburton, William K.; Momayezi, Michael

2006-06-20

A method and apparatus for processing step-like output signals (primary signals) generated by non-ideal, for example, nominally single-pole ("N-1P ") devices. An exemplary method includes creating a set of secondary signals by directing the primary signal along a plurality of signal paths to a signal summation point, summing the secondary signals reaching the signal summation point after propagating along the signal paths to provide a summed signal, performing a filtering or delaying operation in at least one of said signal paths so that the secondary signals reaching said summing point have a defined time correlation with respect to one another, applying a set of weighting coefficients to the secondary signals propagating along said signal paths, and performing a capturing operation after any filtering or delaying operations so as to provide a weighted signal sum value as a measure of the integrated area Q_gT of the input signal.

The evolution of ethylene signaling in plant chemical ecology.

PubMed

Groen, Simon C; Whiteman, Noah K

2014-07-01

Ethylene is a key hormone in plant development, mediating plant responses to abiotic environmental stress, and interactions with attackers and mutualists. Here, we provide a synthesis of the role of ethylene in the context of plant ecology and evolution, and a prospectus for future research in this area. We focus on the regulatory function of ethylene in multi-organismal interactions. In general, plant interactions with different types of organisms lead to reduced or enhanced levels of ethylene. This in turn affects not only the plant's response to the interacting organism at hand, but also to other organisms in the community. These community-level effects become observable as enhanced or diminished relationships with future commensals, and systemic resistance or susceptibility to secondary attackers. Ongoing comparative genomic and phenotypic analyses continue to shed light on these interactions. These studies have revealed that plants and interacting organisms from separate kingdoms of life have independently evolved the ability to produce, perceive, and respond to ethylene. This signature of convergent evolution of ethylene signaling at the phenotypic level highlights the central role ethylene metabolism and signaling plays in plant interactions with microbes and animals.

A biological inspired fuzzy adaptive window median filter (FAWMF) for enhancing DNA signal processing.

PubMed

Ahmad, Muneer; Jung, Low Tan; Bhuiyan, Al-Amin

2017-10-01

Digital signal processing techniques commonly employ fixed length window filters to process the signal contents. DNA signals differ in characteristics from common digital signals since they carry nucleotides as contents. The nucleotides own genetic code context and fuzzy behaviors due to their special structure and order in DNA strand. Employing conventional fixed length window filters for DNA signal processing produce spectral leakage and hence results in signal noise. A biological context aware adaptive window filter is required to process the DNA signals. This paper introduces a biological inspired fuzzy adaptive window median filter (FAWMF) which computes the fuzzy membership strength of nucleotides in each slide of window and filters nucleotides based on median filtering with a combination of s-shaped and z-shaped filters. Since coding regions cause 3-base periodicity by an unbalanced nucleotides' distribution producing a relatively high bias for nucleotides' usage, such fundamental characteristic of nucleotides has been exploited in FAWMF to suppress the signal noise. Along with adaptive response of FAWMF, a strong correlation between median nucleotides and the Π shaped filter was observed which produced enhanced discrimination between coding and non-coding regions contrary to fixed length conventional window filters. The proposed FAWMF attains a significant enhancement in coding regions identification i.e. 40% to 125% as compared to other conventional window filters tested over more than 250 benchmarked and randomly taken DNA datasets of different organisms. This study proves that conventional fixed length window filters applied to DNA signals do not achieve significant results since the nucleotides carry genetic code context. The proposed FAWMF algorithm is adaptive and outperforms significantly to process DNA signal contents. The algorithm applied to variety of DNA datasets produced noteworthy discrimination between coding and non-coding regions contrary to fixed window length conventional filters. Copyright © 2017 Elsevier B.V. All rights reserved.

Intensive removal of signal crayfish (Pacifastacus leniusculus) from rivers increases numbers and taxon richness of macroinvertebrate species.

PubMed

Moorhouse, Tom P; Poole, Alison E; Evans, Laura C; Bradley, David C; Macdonald, David W

2014-02-01

Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfish from UK rivers. Crayfish were intensively trapped and removed from two tributaries of the River Thames to test the hypothesis that lowering signal crayfish densities would result in increases in macroinvertebrate numbers and taxon richness. We removed 6181 crayfish over four sessions, resulting in crayfish densities that decreased toward the center of the removal sections. Conversely in control sections (where crayfish were trapped and returned), crayfish density increased toward the center of the section. Macroinvertebrate numbers and taxon richness were inversely correlated with crayfish densities. Multivariate analysis of the abundance of each taxon yielded similar results and indicated that crayfish removals had positive impacts on macroinvertebrate numbers and taxon richness but did not alter the composition of the wider macroinvertebrate community. Synthesis and applications: Our results demonstrate that non-eradication-oriented crayfish removal programmes may lead to increases in the total number of macroinvertebrates living in the benthos. This represents the first evidence that removing signal crayfish from riparian systems, at intensities feasible during control attempts or commercial crayfishing, may be beneficial for a range of sympatric aquatic macroinvertebrates.

Intensive removal of signal crayfish (Pacifastacus leniusculus) from rivers increases numbers and taxon richness of macroinvertebrate species

PubMed Central

Moorhouse, Tom P; Poole, Alison E; Evans, Laura C; Bradley, David C; Macdonald, David W

2014-01-01

Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfish from UK rivers. Crayfish were intensively trapped and removed from two tributaries of the River Thames to test the hypothesis that lowering signal crayfish densities would result in increases in macroinvertebrate numbers and taxon richness. We removed 6181 crayfish over four sessions, resulting in crayfish densities that decreased toward the center of the removal sections. Conversely in control sections (where crayfish were trapped and returned), crayfish density increased toward the center of the section. Macroinvertebrate numbers and taxon richness were inversely correlated with crayfish densities. Multivariate analysis of the abundance of each taxon yielded similar results and indicated that crayfish removals had positive impacts on macroinvertebrate numbers and taxon richness but did not alter the composition of the wider macroinvertebrate community. Synthesis and applications: Our results demonstrate that non-eradication-oriented crayfish removal programmes may lead to increases in the total number of macroinvertebrates living in the benthos. This represents the first evidence that removing signal crayfish from riparian systems, at intensities feasible during control attempts or commercial crayfishing, may be beneficial for a range of sympatric aquatic macroinvertebrates. PMID:24634733

Community perspectives

NASA Technical Reports Server (NTRS)

1975-01-01

General aviation is considered from the perspective of the local community's decision-making process in determining its needs for access to general aviation services. The decision-making model, preliminary decision, community characteristics, and planning processes are discussed.

Assembly processes of gastropod community change with horizontal and vertical zonation in ancient Lake Ohrid: a metacommunity speciation perspective

NASA Astrophysics Data System (ADS)

Hauffe, Torsten; Albrecht, Christian; Wilke, Thomas

2016-05-01

The Balkan Lake Ohrid is the oldest and most diverse freshwater lacustrine system in Europe. However, it remains unclear whether species community composition, as well as the diversification of its endemic taxa, is mainly driven by dispersal limitation, environmental filtering, or species interaction. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics, as provided by the unifying framework of the "metacommunity speciation model".The current study used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process-based metacommunity analyses. Specifically, the study aimed (1) to identifying the relative importance of the three community assembly processes and (2) to test whether the importance of these individual processes changes gradually with lake depth or discontinuously with eco-zone shifts.Based on automated eco-zone detection and process-specific simulation steps, we demonstrated that dispersal limitation had the strongest influence on gastropod community composition. However, it was not the exclusive assembly process, but acted together with the other two processes - environmental filtering and species interaction. The relative importance of the community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter.This suggests that environmental characteristics have a pronounced effect on shaping gastropod communities via assembly processes. Moreover, the study corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community composition) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental filtering and biotic interaction also suggests a small but significant influence of ecological speciation. These findings contribute to the main goal of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) deep drilling initiative - inferring the drivers of biotic evolution - and might provide an integrative perspective on biological and limnological dynamics in ancient Lake Ohrid.

Neuromimetic Sound Representation for Percept Detection and Manipulation

NASA Astrophysics Data System (ADS)

Zotkin, Dmitry N.; Chi, Taishih; Shamma, Shihab A.; Duraiswami, Ramani

2005-12-01

The acoustic wave received at the ears is processed by the human auditory system to separate different sounds along the intensity, pitch, and timbre dimensions. Conventional Fourier-based signal processing, while endowed with fast algorithms, is unable to easily represent a signal along these attributes. In this paper, we discuss the creation of maximally separable sounds in auditory user interfaces and use a recently proposed cortical sound representation, which performs a biomimetic decomposition of an acoustic signal, to represent and manipulate sound for this purpose. We briefly overview algorithms for obtaining, manipulating, and inverting a cortical representation of a sound and describe algorithms for manipulating signal pitch and timbre separately. The algorithms are also used to create sound of an instrument between a "guitar" and a "trumpet." Excellent sound quality can be achieved if processing time is not a concern, and intelligible signals can be reconstructed in reasonable processing time (about ten seconds of computational time for a one-second signal sampled at [InlineEquation not available: see fulltext.]). Work on bringing the algorithms into the real-time processing domain is ongoing.

Community and individual effects on SOD intensification in California redwood forests: implications for tanoak persistence

Treesearch

Richard C. Cobb; Joao A. N. Filipe; Ross K. Meentemeyer; Chris A. Gilligan; Shannon C. Lynch; David M. Rizzo

2010-01-01

Processes operating across different spatial scales (for example, individual, community, landscape) influence disease dynamics. Understanding these processes and their interactions can yield general insights into disease control, disease dynamics within communities, and community response to disease. For Phytophthora ramorum, pathogen establishment...

Learning Communities for Curriculum Change: Key Factors in an Educational Change Process in New Zealand

ERIC Educational Resources Information Center

Edwards, Frances

2012-01-01

Increasingly school change processes are being facilitated through the formation and operation of groups of teachers working together for improved student outcomes. These groupings are variously referred to as networks, networked learning communities, communities of practice, professional learning communities, learning circles or clusters. The…

Differential capacitance probe for process control involving aqueous dielectric fluids

DOEpatents

Svoboda, John M.; Morrison, John L.

2002-10-08

A differential capacitance probe device for process control involving aqueous dielectric fluids is disclosed. The device contains a pair of matched capacitor probes configured in parallel, one immersed in a sealed container of reference fluid, and the other immersed in the process fluid. The sealed container holding the reference fluid is also immersed in the process fluid, hence both probes are operated at the same temperature. Signal conditioning measures the difference in capacitance between the reference probe and the process probe. The resulting signal is a control error signal that can be used to control the process.

Early-Stage Visual Processing and Cortical Amplification Deficits in Schizophrenia

PubMed Central

Butler, Pamela D.; Zemon, Vance; Schechter, Isaac; Saperstein, Alice M.; Hoptman, Matthew J.; Lim, Kelvin O.; Revheim, Nadine; Silipo, Gail; Javitt, Daniel C.

2005-01-01

Background Patients with schizophrenia show deficits in early-stage visual processing, potentially reflecting dysfunction of the magnocellular visual pathway. The magnocellular system operates normally in a nonlinear amplification mode mediated by glutamatergic (N-methyl-d-aspartate) receptors. Investigating magnocellular dysfunction in schizophrenia therefore permits evaluation of underlying etiologic hypotheses. Objectives To evaluate magnocellular dysfunction in schizophrenia, relative to known neurochemical and neuroanatomical substrates, and to examine relationships between electrophysiological and behavioral measures of visual pathway dysfunction and relationships with higher cognitive deficits. Design, Setting, and Participants Between-group study at an inpatient state psychiatric hospital and out-patient county psychiatric facilities. Thirty-three patients met DSM-IV criteria for schizophrenia or schizoaffective disorder, and 21 nonpsychiatric volunteers of similar ages composed the control group. Main Outcome Measures (1) Magnocellular and parvocellular evoked potentials, analyzed using nonlinear (Michaelis-Menten) and linear contrast gain approaches; (2) behavioral contrast sensitivity measures; (3) white matter integrity; (4) visual and nonvisual neuropsychological measures, and (5) clinical symptom and community functioning measures. Results Patients generated evoked potentials that were significantly reduced in response to magnocellular-biased, but not parvocellular-biased, stimuli (P=.001). Michaelis-Menten analyses demonstrated reduced contrast gain of the magnocellular system (P=.001). Patients showed decreased contrast sensitivity to magnocellular-biased stimuli (P<.001). Evoked potential deficits were significantly related to decreased white matter integrity in the optic radiations (P<.03). Evoked potential deficits predicted impaired contrast sensitivity (P=.002), which was in turn related to deficits in complex visual processing (P≤.04). Both evoked potential (P≤.04) and contrast sensitivity (P=.01) measures significantly predicted community functioning. Conclusions These findings confirm the existence of early-stage visual processing dysfunction in schizophrenia and provide the first evidence that such deficits are due to decreased nonlinear signal amplification, consistent with glutamatergic theories. Neuroimaging studies support the hypothesis of dysfunction within low-level visual pathways involving thalamocortical radiations. Deficits in early-stage visual processing significantly predict higher cognitive deficits. PMID:15867102

Process observation in fiber laser-based selective laser melting

NASA Astrophysics Data System (ADS)

Thombansen, Ulrich; Gatej, Alexander; Pereira, Milton

2015-01-01

The process observation in selective laser melting (SLM) focuses on observing the interaction point where the powder is processed. To provide process relevant information, signals have to be acquired that are resolved in both time and space. Especially in high-power SLM, where more than 1 kW of laser power is used, processing speeds of several meters per second are required for a high-quality processing results. Therefore, an implementation of a suitable process observation system has to acquire a large amount of spatially resolved data at low sampling speeds or it has to restrict the acquisition to a predefined area at a high sampling speed. In any case, it is vitally important to synchronously record the laser beam position and the acquired signal. This is a prerequisite that allows the recorded data become information. Today, most SLM systems employ f-theta lenses to focus the processing laser beam onto the powder bed. This report describes the drawbacks that result for process observation and suggests a variable retro-focus system which solves these issues. The beam quality of fiber lasers delivers the processing laser beam to the powder bed at relevant focus diameters, which is a key prerequisite for this solution to be viable. The optical train we present here couples the processing laser beam and the process observation coaxially, ensuring consistent alignment of interaction zone and observed area. With respect to signal processing, we have developed a solution that synchronously acquires signals from a pyrometer and the position of the laser beam by sampling the data with a field programmable gate array. The relevance of the acquired signals has been validated by the scanning of a sample filament. Experiments with grooved samples show a correlation between different powder thicknesses and the acquired signals at relevant processing parameters. This basic work takes a first step toward self-optimization of the manufacturing process in SLM. It enables the addition of cognitive functions to the manufacturing system to the extent that the system could track its own process. The results are based on analyzing and redesigning the optical train, in combination with a real-time signal acquisition system which provides a solution to certain technological barriers.

Compositional Stability of the Bacterial Community in a Climate-Sensitive Sub-Arctic Peatland

PubMed Central

Weedon, James T.; Kowalchuk, George A.; Aerts, Rien; Freriks, Stef; Röling, Wilfred F. M.; van Bodegom, Peter M.

2017-01-01

The climate sensitivity of microbe-mediated soil processes such as carbon and nitrogen cycling offers an interesting case for evaluating the corresponding sensitivity of microbial community composition to environmental change. Better understanding of the degree of linkage between functional and compositional stability would contribute to ongoing efforts to build mechanistic models aiming at predicting rates of microbe-mediated processes. We used an amplicon sequencing approach to test if previously observed large effects of experimental soil warming on C and N cycle fluxes (50–100% increases) in a sub-arctic Sphagnum peatland were reflected in changes in the composition of the soil bacterial community. We found that treatments that previously induced changes to fluxes did not associate with changes in the phylogenetic composition of the soil bacterial community. For both DNA- and RNA-based analyses, variation in bacterial communities could be explained by the hierarchy: spatial variation (12–15% of variance explained) > temporal variation (7–11%) > climate treatment (4–9%). We conclude that the bacterial community in this environment is stable under changing conditions, despite the previously observed sensitivity of process rates—evidence that microbe-mediated soil processes can alter without concomitant changes in bacterial communities. We propose that progress in linking soil microbial communities to ecosystem processes can be advanced by further investigating the relative importance of community composition effects versus physico-chemical factors in controlling biogeochemical process rates in different contexts. PMID:28326062