Sample records for acoustics temporal patterns

  1. Syllable acoustics, temporal patterns, and call composition vary with behavioral context in Mexican free-tailed bats

    E-print Network

    Bohn, Kirsten

    Syllable acoustics, temporal patterns, and call composition vary with behavioral context in Mexican has shown that some bat species have rich vocal repertoires with diverse syllable acoustics. Few repertoire of Mexican free-tailed bats, T. brasiliensis, is presented. Syllable acoustics and temporal

  2. Syllable acoustics, temporal patterns, and call composition vary with behavioral context in Mexican free-tailed bats

    PubMed Central

    Bohn, Kirsten M.; Schmidt-French, Barbara; Ma, Sean T.; Pollak, George D.

    2008-01-01

    Recent research has shown that some bat species have rich vocal repertoires with diverse syllable acoustics. Few studies, however, have compared vocalizations across different behavioral contexts or examined the temporal emission patterns of vocalizations. In this paper, a comprehensive examination of the vocal repertoire of Mexican free-tailed bats, T. brasiliensis, is presented. Syllable acoustics and temporal emission patterns for 16 types of vocalizations including courtship song revealed three main findings. First, although in some cases syllables are unique to specific calls, other syllables are shared among different calls. Second, entire calls associated with one behavior can be embedded into more complex vocalizations used in entirely different behavioral contexts. Third, when different calls are composed of similar syllables, distinctive temporal emission patterns may facilitate call recognition. These results indicate that syllable acoustics alone do not likely provide enough information for call recognition; rather, the acoustic context and temporal emission patterns of vocalizations may affect meaning. PMID:19045674

  3. In-Situ Optical and Acoustical Measurements of the Buoyant Cyanobacterium P. Rubescens: Spatial and Temporal Distribution Patterns

    PubMed Central

    Hofmann, Hilmar; Peeters, Frank

    2013-01-01

    Optical (fluorescence) and acoustic in-situ techniques were tested in their ability to measure the spatial and temporal distribution of plankton in freshwater ecosystems with special emphasis on the harmful and buoyant cyanobacterium P. rubescens. Fluorescence was measured with the multi-spectral FluoroProbe (Moldaenke FluoroProbe, MFP) and a Seapoint Chlorophyll Fluorometer (SCF). In-situ measurements of the acoustic backscatter strength (ABS) were conducted with three different acoustic devices covering multiple acoustic frequencies (614 kHz ADCP, 2 MHz ADP, and 6 MHz ADV). The MFP provides a fast and reliable technique to measure fluorescence at different wavelengths in situ, which allows discriminating between P. rubescens and other phytoplankton species. All three acoustic devices are sensitive to P. rubescens even if other scatterers, e.g., zooplankton or suspended sediment, are present in the water column, because P. rubescens containing gas vesicles has a strong density difference and hence acoustic contrast to the ambient water and other scatterers. After calibration, the combination of optical and acoustical measurements not only allows qualitative and quantitative observation of P. rubescens, but also distinction between P. rubescens, other phytoplankton, and zooplankton. As the measuring devices can sample in situ at high rates they enable assessment of plankton distributions at high temporal (minutes) and spatial (decimeters) resolution or covering large temporal (seasonal) and spatial (basin scale) scales. PMID:24303028

  4. Online temporal pattern learning

    Microsoft Academic Search

    Nastaran Farahmand; Mir Hossein Dezfoulian; Hossein GhiasiRad; Alireza Mokhtari; Ali Nouri

    2009-01-01

    This paper describes a biologically motivated approach, using hierarchical temporal memory (HTM), to build a high-level self-organizing visual system for a soccer bot. Meanwhile it presents two unsupervised online learning algorithms for temporal patterns in HTMs. The algorithms were implemented in a simulated soccer bot for a real-world evaluation. After a training phase, the robot was able to recognize different

  5. Temporal integration of acoustic energy.

    PubMed

    Pedersen, C B; Salomon, G

    1977-01-01

    Perception of sound shows an increase in loudness related to the duration of the acoustic stimulus. This phenomenon has been studied at threshold (temporal integration) in normal and impaired ears. Normal ears showed an improved threshold with impulse durations up to 200 msec. In cochlear hearing loss, regardless of pathology, the threshold improvement was reduced. A method to evaluate these changes has been designed (Brief Tone Audiometry). When using this method, a quantitative comparison showed the same reduction in temporal integration in ears with hearing loss, regardless of pathology. By using a loudness balance test, the increase in loudness related to prolongation of the stimulus was investigated (Loudness Summation). Loudness growth was measured at various intensities and the results from normal and hearing-impaired ears were compared. At a given sound intensity both normal and hearing-impaired ears showed the same Loudness Summation, which in turn showed a simple relationship to Brief Tone Audiometry in impaired ears. Physiological and diagnostic aspects of these findings are discussed. PMID:888677

  6. Temporal spike pattern learning

    NASA Astrophysics Data System (ADS)

    Talathi, Sachin S.; Abarbanel, Henry D. I.; Ditto, William L.

    2008-09-01

    Sensory systems pass information about an animal’s environment to higher nervous system units through sequences of action potentials. When these action potentials have essentially equivalent wave forms, all information is contained in the interspike intervals (ISIs) of the spike sequence. How do neural circuits recognize and read these ISI sequences? We address this issue of temporal sequence learning by a neuronal system utilizing spike timing dependent plasticity (STDP). We present a general architecture of neural circuitry that can perform the task of ISI recognition. The essential ingredients of this neural circuit, which we refer to as “interspike interval recognition unit” (IRU) are (i) a spike selection unit, the function of which is to selectively distribute input spikes to downstream IRU circuitry; (ii) a time-delay unit that can be tuned by STDP; and (iii) a detection unit, which is the output of the IRU and a spike from which indicates successful ISI recognition by the IRU. We present two distinct configurations for the time-delay circuit within the IRU using excitatory and inhibitory synapses, respectively, to produce a delayed output spike at time t0+?(R) in response to the input spike received at time t0 . R is the tunable parameter of the time-delay circuit that controls the timing of the delayed output spike. We discuss the forms of STDP rules for excitatory and inhibitory synapses, respectively, that allow for modulation of R for the IRU to perform its task of ISI recognition. We then present two specific implementations for the IRU circuitry, derived from the general architecture that can both learn the ISIs of a training sequence and then recognize the same ISI sequence when it is presented on subsequent occasions.

  7. Temporal pattern processing in songbirds.

    PubMed

    Comins, Jordan A; Gentner, Timothy Q

    2014-10-01

    Understanding how the brain perceives, organizes and uses patterned information is directly related to the neurobiology of language. Given the present limitations, such knowledge at the scale of neurons, neural circuits and neural populations can only come from non-human models, focusing on shared capacities that are relevant to language processing. Here we review recent advances in the behavioral and neural basis of temporal pattern processing of natural auditory communication signals in songbirds, focusing on European starlings. We suggest a general inhibitory circuit for contextual modulation that can act to control sensory representations based on patterning rules. PMID:25201176

  8. Writing magnetic patterns with surface acoustic waves

    SciTech Connect

    Li, Weiyang; Buford, Benjamin; Jander, Albrecht; Dhagat, Pallavi, E-mail: dhagat@eecs.oregonstate.edu [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, Oregon 97331 (United States)

    2014-05-07

    A novel patterning technique that creates magnetization patterns in a continuous magnetostrictive film with surface acoustic waves is demonstrated. Patterns of 10??m wide stripes of alternating magnetization and a 3??m dot of reversed magnetization are written using standing and focusing acoustic waves, respectively. The magnetization pattern is size-tunable, erasable, and rewritable by changing the magnetic field and acoustic power. This versatility, along with its solid-state implementation (no moving parts) and electronic control, renders it as a promising technique for application in magnetic recording, magnonic signal processing, magnetic particle manipulation, and spatial magneto-optical modulation.

  9. Diel patterns and temporal trends in spawning activities of Robust Redhorse and River Redhorse in Georgia, assessed using passive acoustic monitoring

    USGS Publications Warehouse

    Straight, Carrie A.; Jackson, C. Rhett; Freeman, Byron J.; Freeman, Mary C.

    2015-01-01

    The conservation of imperiled species depends upon understanding threats to the species at each stage of its life history. In the case of many imperiled migratory fishes, understanding how timing and environmental influences affect reproductive behavior could provide managers with information critical for species conservation. We used passive acoustic recorders to document spawning activities for two large-bodied catostomids (Robust Redhorse Moxostoma robustum in the Savannah and Broad rivers, Georgia, and River Redhorse M. carinatum in the Coosawattee River, Georgia) in relation to time of day, water temperature, discharge variation, moonlight, and weather. Robust Redhorse spawning activities in the Savannah and Broad rivers were more frequent at night or in the early morning (0100–0400 hours and 0800–1000 hours, respectively) and less frequent near midday (1300 hours). Spawning attempts in the Savannah and Broad rivers increased over a 3–4-d period and then declined. River Redhorse spawning activities in the Coosawattee River peaked on the first day of recording and declined over four subsequent days; diel patterns were less discernible, although moon illumination was positively associated with spawning rates, which was also observed for Robust Redhorses in the Savannah River. Spawning activity in the Savannah and Broad rivers was negatively associated with water temperature, and spawning activity increased in association with cloud cover in the Savannah River. A large variation in discharge was only measured in the flow-regulated Savannah River and was not associated with spawning attempts. To our knowledge, this is the first study to show diel and multiday patterns in spawning activities for anyMoxostoma species. These patterns and relationships between the environment and spawning activities could provide important information for the management of these species downstream of hydropower facilities.

  10. Transduction of temporal patterns by single neurons.

    PubMed

    Hooper, S L

    1998-12-01

    As our ability to communicate by Morse code illustrates, nervous systems can produce motor outputs, and identify sensory inputs, based on temporal patterning alone. Although this ability is central to a wide range of sensory and motor tasks, the ways in which nervous systems represent temporal patterns are not well understood. I show here that individual neurons of the lobster pyloric network can integrate rhythmic patterned input over the long times (hundreds of milliseconds) characteristic of many behaviorally relevant patterns, and that their firing delays vary as a graded function of the pattern's temporal character. These neurons directly transduce temporal patterns into a neural code, and constitute a novel biological substrate for temporal pattern detection and production. The combined activities of several such neurons can encode simple rhythmic patterns, and I provide a model illustrating how this could be achieved. PMID:10196589

  11. Discovering Phonetic Coherence in Acoustic Patterns*

    E-print Network

    Discovering Phonetic Coherence in Acoustic Patterns* Catherine T. Best,t Michael Studdert signal, listeners normally report coherent phonetic patterns corresponding to the phonemes of a language that they know. What is the basis for the internal coherence of phonetic segments? On one account, listeners

  12. Temporal patterning of neural progenitors in Drosophila.

    PubMed

    Li, Xin; Chen, Zhenqing; Desplan, Claude

    2013-01-01

    Drosophila has recently become a powerful model system to understand the mechanisms of temporal patterning of neural progenitors called neuroblasts (NBs). Two different temporal sequences of transcription factors (TFs) have been found to be sequentially expressed in NBs of two different systems: the Hunchback, Krüppel, Pdm1/Pdm2, Castor, and Grainyhead sequence in the Drosophila ventral nerve cord; and the Homothorax, Klumpfuss, Eyeless, Sloppy-paired, Dichaete, and Tailless sequence that patterns medulla NBs. In addition, the intermediate neural progenitors of type II NB lineages are patterned by a different sequence: Dichaete, Grainyhead, and Eyeless. These three examples suggest that temporal patterning of neural precursors by sequences of TFs is a common theme to generate neural diversity. Cross-regulations, including negative feedback regulation and positive feedforward regulation among the temporal factors, can facilitate the progression of the sequence. However, there are many remaining questions to understand the mechanism of temporal transitions. The temporal sequence progression is intimately linked to the progressive restriction of NB competence, and eventually determines the end of neurogenesis. Temporal identity has to be integrated with spatial identity information, as well as with the Notch-dependent binary fate choices, in order to generate specific neuron fates. PMID:23962839

  13. Mining Sequential Patterns from Temporal Streaming Data

    E-print Network

    Malerba, Donato

    Mining Sequential Patterns from Temporal Streaming Data A. Marascu and F. Masseglia INRIA Sophia.Marascu,Florent.Masseglia}@sophia.inria.fr Abstract. In recent years, emerging applications introduced new con- straints for data mining methods of our knowledge, no method has been proposed for mining sequential patterns in data streams. We argue

  14. Resurgence of Temporal Patterns of Responding

    ERIC Educational Resources Information Center

    Cancado, Carlos R. X.; Lattal, Kennon A.

    2011-01-01

    The resurgence of temporal patterns of key pecking by pigeons was investigated in two experiments. In Experiment 1, positively accelerated and linear patterns of responding were established on one key under a discrete-trial multiple fixed-interval variable-interval schedule. Subsequently, only responses on a second key produced reinforcers…

  15. Significance of temporal and spectral acoustic cues for sexual recognition in Xenopus laevis.

    PubMed

    Vignal, Clémentine; Kelley, Darcy

    2007-02-22

    As in many anurans, males of the totally aquatic species, Xenopus laevis, advertise their sexual receptivity using vocalizations. Unusually for anurans, X. laevis females also advertise producing a fertility call that results in courtship duets between partners. Although all X. laevis calls consist of repetitive click trains, male and female calls exhibit sex-specific acoustic features that might convey sexual identity. We tested the significance of the carrier frequency and the temporal pattern of calls using underwater playback experiments in which modified calls were used to evoke vocal responses in males. Since males respond differently to male and female calls, the modification of a key component of sexual identity in calls should change the male's response. We found that a female-like slow call rhythm triggers more vocal activity than a male-like fast rhythm. A call containing both a female-like temporal pattern and a female-like carrier frequency elicits higher levels of courtship display than either feature alone. In contrast, a male-like temporal pattern is sufficient to trigger typical male-male encounter vocalizations regardless of spectral cues. Thus, our evidence supports a role for temporal acoustic cues in sexual identity recognition and for spectral acoustic cues in conveying female attractiveness in X. laevis. PMID:17476767

  16. Temporal Dynamics for Blind Measurement of Room Acoustical Parameters

    Microsoft Academic Search

    Tiago H. Falk; Wai-Yip Chan

    2010-01-01

    In this paper, short- and long-term temporal dynamic information is investigated for the blind measurement of room acoustical parameters. In particular, estimators of room reverberation time (T60) and direct-to-reverberant energy ratio (DRR) are proposed. Short-term temporal dynamic information is obtained from differential (delta) cepstral coefficients. The statistics computed from the zeroth-order delta cepstral sequence serve as input features to a

  17. Spatial and temporal patterns of morel fruiting

    Microsoft Academic Search

    Jeanne D. Mihail; Johann N. Bruhn; Pierluigi Bonello

    2007-01-01

    The biotic and abiotic factors conditioning morel fruit body production are incompletely known. We examined spatial and temporal patterns of Morchella esculenta fruiting over five years in a wooded site in Missouri, USA. Fruiting onset was inversely correlated with spring air and soil temperatures, whereas abundance was positively correlated with rain events (>10mm) during the 30d preceding fruiting. The two

  18. Acoustic and Temporal Partitioning of Cicada Assemblages in City and Mountain Environments

    PubMed Central

    Shieh, Bao-Sen; Liang, Shih-Hsiung; Chiu, Yuh-Wen

    2015-01-01

    Comparing adaptations to noisy city environments with those to natural mountain environments on the community level can provide significant insights that allow an understanding of the impact of anthropogenic noise on invertebrates that employ loud calling songs for mate attraction, especially when each species has its distinct song, as in the case of cicadas. In this study, we investigated the partitioning strategy of cicada assemblages in city and mountain environments by comparing the acoustic features and calling activity patterns of each species, recorded using automated digital recording systems. Our comparison of activity patterns of seasonal and diel calling revealed that there was no significant temporal partitioning of cicada assemblages in either environment. In addition, there was no correlation between the acoustic distance based on spectral features and temporal segregation. Heterospecific spectral overlap was low in both city and mountain environments, although city and mountain cicada assemblages were subject to significantly different levels of anthropogenic or interspecific noise. Furthermore, for the common species found in both environments, the calling activity patterns at both seasonal and diel time scales were significantly consistent across sites and across environments. We suggest that the temporal calling activity is constrained by endogenous factors for each species and is less flexible in response to external factors, such as anthropogenic noise. As a result, cicada assemblages in city environments with low species diversity do not demonstrate a more significant temporal partitioning than those in mountain environments with high species diversity. PMID:25590620

  19. Spatial and temporal patterns of morel fruiting.

    PubMed

    Mihail, Jeanne D; Bruhn, Johann N; Bonello, Pierluigi

    2007-03-01

    The biotic and abiotic factors conditioning morel fruit body production are incompletely known. We examined spatial and temporal patterns of Morchella esculenta fruiting over five years in a wooded site in Missouri, USA. Fruiting onset was inversely correlated with spring air and soil temperatures, whereas abundance was positively correlated with rain events (>10mm) during the 30 d preceding fruiting. The two years with the greatest fruiting had the shortest fruiting seasons (6-7d). Fruiting season length was positively correlated with soil warming, suggesting that a narrow range of optimum soil temperatures favour the explosive production of fruit bodies. All woody stems of at least 1cm diam were mapped and stem diameter and crown condition were noted. Morel fruit bodies were significantly closer to stems of Carya spp., Tilia americana and Ulmus americana than predicted by the frequencies of these woody species or their contribution to the total basal area on the site. Although intra-annual clustering of fruit bodies was often observed, inter-annual clustering was not. The spatial pattern of M. esculenta fruiting appears to be associated with vegetation pattern, whereas the onset and abundance of fruiting are determined by the interaction of spring temperatures with availability of supporting precipitation. PMID:17363234

  20. Neural network systems for multi-dimensional temporal pattern classification

    Microsoft Academic Search

    R. Srinivasan; C. Wang; W. K. Ho; K. W. Lim

    2005-01-01

    Classification of multivariate, multi-class, temporal patterns is an important yet challenging problem that arises during state identification in agile processes. In this paper, we propose two new neural network structures that overcome the curse of dimensionality and the complexities in temporal pattern recognition. The one-variable-one-network (OVON) architecture decomposes the problem in the variable dimension—univariate temporal patterns, called sub-states, are first

  1. A SPATIO-TEMPORAL GENERALIZED FOURIER DOMAIN FRAMEWORK TO ACOUSTIC MODELING IN ENCLOSED SPACES

    E-print Network

    A SPATIO-TEMPORAL GENERALIZED FOURIER DOMAIN FRAMEWORK TO ACOUSTIC MODELING IN ENCLOSED SPACES thousands of acoustic input/output channels [2]. It is clear that to enable real- time, full for multichannel acoustical modeling in enclosed spaces. In Fourier analysis, it is well known that sampling in one

  2. Acoustic backscattering by Hawaiian lutjanid snappers. II. Broadband temporal and spectral structure

    E-print Network

    Benoit-Bird, Kelly J.

    Acoustic backscattering by Hawaiian lutjanid snappers. II. Broadband temporal and spectral The characteristics of acoustic echoes from six species of deep-dwelling up to 400 m Hawaiian Lujanid snappers were consistent within species and were easily distinguishable between species. © 2003 Acoustical Society

  3. Dynamic membrane structure induces temporal pattern formation.

    PubMed

    Lippoldt, J; Händel, C; Dietrich, U; Käs, J A

    2014-10-01

    The understanding of temporal pattern formation in biological systems is essential for insights into regulatory processes of cells. Concerning this problem, the present work introduces a model to explain the attachment/detachment cycle of MARCKS and PKC at the cell membrane, which is crucial for signal transduction processes. Our model is novel with regard to its driving mechanism: Structural changes within the membrane fuel an activator-inhibitor based global density oscillation of membrane related proteins. Based on simulated results of our model, phase diagrams were generated to illustrate the interplay of MARCKS and PKC. They predict the oscillatory behavior in the form of the number of peaks, the periodic time, and the damping constant depending on the amounts of MARCKS and PKC, respectively. The investigation of the phase space also revealed an unexpected intermediate state prior to the oscillations for high amounts of MARCKS in the system. The validation of the obtained results was carried out by stability analysis, which also accounts for further enhanced understanding of the studied system. It was shown, that the occurrence of the oscillating behavior is independent of the diffusion and the consumption of the reactants. The diffusion terms in the used reaction-diffusion equations only act as modulating terms and are not required for the oscillation. The hypothesis of our work suggests a new mechanism of temporal pattern formation in biological systems. This mechanism includes a classical activator-inhibitor system, but is based on the modifications of the membrane structure, rather than a reaction-diffusion system. PMID:24866013

  4. A pattern matching language for spatio-temporal databases

    Microsoft Academic Search

    Tsz S. Cheng; Shashi K. Gadia

    1994-01-01

    We propose a pattern matching language for spatio-temporal databases. The matching process in time dimension is based upon the evolutionary nature of time, but in spatial dimension it is based on placement, shape and sizes of regions. The concept of pattern matching introduced in this paper is independent of the choice of the underlying model for spatio-temporal databases. In particular,

  5. TEMPORAL PATTERN DISCOVERY FOR ANOMALY DETECTION IN A SMART HOME

    E-print Network

    Cook, Diane J.

    TEMPORAL PATTERN DISCOVERY FOR ANOMALY DETECTION IN A SMART HOME Vikramaditya Jakkula , Diane J, cook}@eecs.wsu.edu Keywords: Knowledge discovery, smart homes, anomaly detection, temporal relations with a better understanding of patterns over time. Detecting anomalies in such datasets is a complex

  6. Acoust. Sci. & Tech. 22, 2 (2001) Temporal coding of sensory information in the brain

    E-print Network

    Cariani, Peter

    2001-01-01

    Acoust. Sci. & Tech. 22, 2 (2001) TUTORIAL Temporal coding of sensory information in the brain@epl.meei.harvard.edu Abstract: Physiological and psychophysical evidence for temporal coding of sensory qualities in dif- ferent, proprioception, and vision. In phase-locked systems, temporal differ- ences between sensory surfaces can subserve

  7. Acoustic Predictors of Intelligibility for Segmentally Interrupted Speech: Temporal Envelope, Voicing, and Duration

    ERIC Educational Resources Information Center

    Fogerty, Daniel

    2013-01-01

    Purpose: Temporal interruption limits the perception of speech to isolated temporal glimpses. An analysis was conducted to determine the acoustic parameter that best predicts speech recognition from temporal fragments that preserve different types of speech information--namely, consonants and vowels. Method: Young listeners with normal hearing…

  8. Scaling properties in temporal patterns of schizophrenia

    NASA Astrophysics Data System (ADS)

    Dünki, R. M.; Ambühl, B.

    1996-02-01

    Investigations into the patterns of schizophrenia reveal evidence of scaling properties in temporal behaviour. This is shown in the spectral properties of mid-range and long-range (up to two years) daily recordings from a sample of patients drawn at the therapeutic dwelling SOTERIA (Ambühl et al., in: Springer Series in Synergetics, Vol. 58, eds. Tschacher et al. (Springer, Berlin, 1992) pp. 195-203 and references therein) of the Psychiatric University Hospital in Bern. The therapeutic setting is unique in that it tries to avoid treatment by medication. Power law behaviour has been found within fractal walk analysis and Fourier spectra for the daily fluctuations. A simple dynamic principle, based on a generic intermittency model, is put in relation to these time series thus predicting an additional scaling law for the distribution P( T) of time spans T between successive hospitalizations. Testing this hypothesis with our data shows only insignificant deviations. A possible role of this dynamic principle in the risk assignment of psychotic phases is explored with the help of an example.

  9. Surface wave patterns on acoustically levitated viscous liquid alloys

    NASA Astrophysics Data System (ADS)

    Hong, Z. Y.; Yan, N.; Geng, D. L.; Wei, B.

    2014-04-01

    We demonstrate two different kinds of surface wave patterns on viscous liquid alloys, which are melted and solidified under acoustic levitation condition. These patterns are consistent with the morphologies of standing capillary waves and ensembles of oscillons, respectively. The rapid solidification of two-dimensional liquid alloy surfaces may hold them down.

  10. Investigation of acoustic streaming patterns around oscillating sharp edges

    E-print Network

    Nama, Nitesh; Huang, Tony Jun; Costanzo, Francesco

    2014-01-01

    Oscillating sharp edges have been employed to achieve rapid and homogeneous mixing in microchannels using acoustic streaming. Here we use a perturbation approach to study the flow around oscillating sharp edges in a microchannel. This work extends prior experimental studies to numerically characterize the effect of various parameters on the acoustically induced flow. Our numerical results match well with the experimental results. We investigated multiple device parameters such as the tip angle, oscillation amplitude, and channel dimensions. Our results indicate that, due to the inherent nonlinearity of acoustic streaming, the channel dimensions could significantly impact the flow patterns and device performance.

  11. Coding of multisensory temporal patterns in human superior temporal sulcus

    PubMed Central

    Noesselt, Tömme; Bergmann, Daniel; Heinze, Hans-Jochen; Münte, Thomas; Spence, Charles

    2012-01-01

    Philosophers, psychologists, and neuroscientists have long been interested in how the temporal aspects of perception are represented in the brain. In the present study, we investigated the neural basis of the temporal perception of synchrony/asynchrony for audiovisual speech stimuli using functional magnetic resonance imaging (fMRI). Subjects judged the temporal relation of (a)synchronous audiovisual speech streams, and indicated any changes in their perception of the stimuli over time. Differential hemodynamic responses for synchronous versus asynchronous stimuli were observed in the multisensory superior temporal sulcus complex (mSTS-c) and prefrontal cortex. Within mSTS-c we found adjacent regions expressing an enhanced BOLD-response to the different physical (a)synchrony conditions. These regions were further modulated by the subjects' perceptual state. By calculating the distances between the modulated regions within mSTS-c in single-subjects we demonstrate that the “auditory leading (AL)” and “visual leading (VL) areas” lie closer to “synchrony areas” than to each other. Moreover, analysis of interregional connectivity indicates a stronger functional connection between multisensory prefrontal cortex and mSTS-c during the perception of asynchrony. Taken together, these results therefore suggest the presence of distinct sub-regions within the human STS-c for the maintenance of temporal relations for audiovisual speech stimuli plus differential functional connectivity with prefrontal regions. The respective local activity in mSTS-c is dependent both upon the physical properties of the stimuli presented and upon the subjects' perception of (a)synchrony. PMID:22973202

  12. Significance of temporal and spectral acoustic cues for sexual recognition in Xenopus laevis

    E-print Network

    Kelley, Darcy B.

    receptivity vocally, this species offers a rare opportunity to investigate acoustic recognition of sexSignificance of temporal and spectral acoustic cues for sexual recognition in Xenopus laevis Cle As in many anurans, males of the totally aquatic species, Xenopus laevis, advertise their sexual receptivity

  13. Acoustical Survey of Methane Plumes on North Hydrate Ridge: Constraining Temporal and Spatial Characteristics

    Microsoft Academic Search

    P. K. Kannberg; A. M. Trehu

    2008-01-01

    While methane plumes associated with hydrate formations have been acoustically imaged before, little is known about their temporal characteristics. Previous acoustic surveys have focused on determining plume location, but as far as we know, multiple, repeated surveys of the same plume have not been done prior to the survey presented here. In July 2008, we acquired sixteen identical surveys within

  14. Finding Spatio-Temporal Patterns in Large Sensor Datasets

    ERIC Educational Resources Information Center

    McGuire, Michael Patrick

    2010-01-01

    Spatial or temporal data mining tasks are performed in the context of the relevant space, defined by a spatial neighborhood, and the relevant time period, defined by a specific time interval. Furthermore, when mining large spatio-temporal datasets, interesting patterns typically emerge where the dataset is most dynamic. This dissertation is…

  15. VizPattern: Interactive Querying of Temporal Patterns by Example

    Microsoft Academic Search

    Jing Jin; Pedro Szekely

    In many domains, visualizations help users identify patterns in tem- poral data. However, being able to see patterns is not enough. For example, after spotting an example of a particular pattern, users often want to see all the instances of this pattern and its varia- tions. However, the simple browsing techniques such as filtering and zooming found in most existing

  16. Tunable Nanowire Patterning Using Standing Surface Acoustic Waves

    PubMed Central

    Chen, Yuchao; Ding, Xiaoyun; Lin, Sz-Chin Steven; Yang, Shikuan; Huang, Po-Hsun; Nama, Nitesh; Zhao, Yanhui; Nawaz, Ahmad Ahsan; Guo, Feng; Wang, Wei; Gu, Yeyi; Mallouk, Thomas E.; Huang, Tony Jun

    2014-01-01

    Patterning of nanowires in a controllable, tunable manner is important for the fabrication of functional nanodevices. Here we present a simple approach for tunable nanowire patterning using standing surface acoustic waves (SSAW). This technique allows for the construction of large-scale nanowire arrays with well-controlled patterning geometry and spacing within 5 seconds. In this approach, SSAWs were generated by interdigital transducers (IDTs), which induced a periodic alternating current (AC) electric field on the piezoelectric substrate and consequently patterned metallic nanowires in suspension. The patterns could be deposited onto the substrate after the liquid evaporated. By controlling the distribution of the SSAW field, metallic nanowires were assembled into different patterns including parallel and perpendicular arrays. The spacing of the nanowire arrays could be tuned by controlling the frequency of the surface acoustic waves. Additionally, we observed 3D spark-shape nanowire patterns in the SSAW field. The SSAW-based nanowire-patterning technique presented here possesses several advantages over alternative patterning approaches, including high versatility, tunability, and efficiency, making it promising for device applications. PMID:23540330

  17. Temporal coherence of acoustic rays and modes using the path integral approach.

    PubMed

    Yang, T C

    2012-06-01

    Acoustic propagation can be described by rays and normal modes. Applying the path integral to refractive rays in three dimensional space, Dashen et al. [J. Acoust. Soc. Am. 77, 1716-1722 (1985)] derived the mutual coherence function of the acoustic field. For shallow water where sound interacts with boundaries, the acoustic field can be described by vertical modes and horizontal rays. Applying the path integral to the horizontal rays, one obtains the mutual coherence function of the normal modes. This paper applies this formulation to the derivation of the temporal coherence function of individual modes and also that of the acoustic field in the presence of linear internal waves. The effects of mode coupling due to internal waves on temporal coherence loss are illustrated with numerical calculations. PMID:22712918

  18. Temporal Patterns of Communication in the Workplace

    ERIC Educational Resources Information Center

    Su, Norman Makoto

    2009-01-01

    In this dissertation, we report on results of an in-depth observational study to understand the temporal dimension of communication in the workplace. By employing the "shadowing" method for in situ to-the-second data gathering of information workers' behaviors, we gained a detailed snapshot of informants' workdays, "warts and all." Our…

  19. T-Patterns Revisited: Mining for Temporal Patterns in Sensor Data

    PubMed Central

    Salah, Albert Ali; Pauwels, Eric; Tavenard, Romain; Gevers, Theo

    2010-01-01

    The trend to use large amounts of simple sensors as opposed to a few complex sensors to monitor places and systems creates a need for temporal pattern mining algorithms to work on such data. The methods that try to discover re-usable and interpretable patterns in temporal event data have several shortcomings. We contrast several recent approaches to the problem, and extend the T-Pattern algorithm, which was previously applied for detection of sequential patterns in behavioural sciences. The temporal complexity of the T-pattern approach is prohibitive in the scenarios we consider. We remedy this with a statistical model to obtain a fast and robust algorithm to find patterns in temporal data. We test our algorithm on a recent database collected with passive infrared sensors with millions of events. PMID:22163613

  20. Spatial and temporal variability of zooplankton off New Caledonia (Southwestern Pacific) from acoustics and net measurements

    NASA Astrophysics Data System (ADS)

    Smeti, Houssem; Pagano, Marc; Menkes, Christophe; Lebourges-Dhaussy, Anne; Hunt, Brian P. V.; Allain, Valerie; Rodier, Martine; de Boissieu, Florian; Kestenare, Elodie; Sammari, Cherif

    2015-04-01

    Spatial and temporal distribution of zooplankton off New Caledonia in the eastern Coral Sea was studied during two multidisciplinary cruises in 2011, during the cool and the hot seasons. Acoustic measurements of zooplankton were made using a shipborne acoustic Doppler current profiler (S-ADCP), a scientific echosounder and a Tracor acoustic profiling system (TAPS). Relative backscatter from ADCP was converted to biomass estimates using zooplankton weights from net-samples collected during the cruises. Zooplankton biomass was estimated using four methods: weighing, digital imaging (ZooScan), ADCP and TAPS. Significant correlations were found between the different biomass estimators and between the backscatters of the ADCP and the echosounder. There was a consistent diel pattern in ADCP derived biomass and echosounder backscatter resulting from the diel vertical migration (DVM) of zooplankton. Higher DVM amplitudes were associated with higher abundance of small zooplankton and cold waters to the south of the study area, while lower DVM amplitudes in the north were associated with warmer waters and higher abundance of large organisms. Zooplankton was largely dominated by copepods (71-73%) among which calanoids prevailed (40-42%), with Paracalanus spp. as the dominant species (16-17%). Overall, zooplankton exhibited low abundance and biomass (mean night dry biomass of 4.7 ± 2.2 mg m3 during the cool season and 2.4 ± 0.4 mg m3 during the hot season) but high richness and diversity (Shannon index ˜4). Substantially enhanced biomass and abundance appeared to be episodically associated with mesoscale features contributing to shape a rather patchy zooplankton distribution.

  1. Temporal patterning of Drosophila medulla neuroblasts controls neural fates

    PubMed Central

    Li, Xin; Erclik, Ted; Bertet, Claire; Chen, Zhenqing; Voutev, Roumen; Venkatesh, Srinidhi; Morante, Javier; Celik, Arzu; Desplan, Claude

    2013-01-01

    In the Drosophila optic lobes, the medulla processes visual information coming from inner photoreceptors R7 and R8 and from lamina neurons. It contains ~40,000 neurons belonging to over 70 different types. We describe how precise temporal patterning of neural progenitors generates these different neural types. Five transcription factors--Homothorax, Eyeless, Sloppy-paired, Dichaete and Tailless--are sequentially expressed in a temporal cascade in each of the medulla neuroblasts as they age. Loss of either Eyeless, Sloppy-paired or Dichaete blocks further progression of the temporal sequence. We provide evidence that this temporal sequence in neuroblasts, together with Notch-dependent binary fate choice, controls the diversification of the neuronal progeny. Although a temporal sequence of transcription factors had been identified in Drosophila embryonic neuroblasts, our work illustrates the generality of this strategy, with different sequences of transcription factors being used in different contexts. PMID:23783517

  2. Detecting multineuronal temporal patterns in parallel spike trains.

    PubMed

    Gansel, Kai S; Singer, Wolf

    2012-01-01

    We present a non-parametric and computationally efficient method that detects spatiotemporal firing patterns and pattern sequences in parallel spike trains and tests whether the observed numbers of repeating patterns and sequences on a given timescale are significantly different from those expected by chance. The method is generally applicable and uncovers coordinated activity with arbitrary precision by comparing it to appropriate surrogate data. The analysis of coherent patterns of spatially and temporally distributed spiking activity on various timescales enables the immediate tracking of diverse qualities of coordinated firing related to neuronal state changes and information processing. We apply the method to simulated data and multineuronal recordings from rat visual cortex and show that it reliably discriminates between data sets with random pattern occurrences and with additional exactly repeating spatiotemporal patterns and pattern sequences. Multineuronal cortical spiking activity appears to be precisely coordinated and exhibits a sequential organization beyond the cell assembly concept. PMID:22661942

  3. Tunable patterning of microparticles and cells using standing surface acoustic Xiaoyun Ding,{a

    E-print Network

    demonstrated an ``acoustic tweezers'' technique, in which micro-objects were effectively patterned using#12;x Tunable patterning of microparticles and cells using standing surface acoustic waves Xiaoyun*a Received 20th October 2011, Accepted 3rd April 2012 DOI: 10.1039/c2lc21021e We have developed an acoustic

  4. Identification of cylindrical shells with sets of reinforcing ribs by their acoustic Bragg diffraction (grating) patterns

    Microsoft Academic Search

    Donald Brill; Guillermo C. Gaunaurd

    1995-01-01

    The authors present a basic study of the acoustic Bragg diffraction patterns produced by gratings with various types of slits, which are insonified by (monochromatic) acoustic waves of various frequencies. Given the spacing in between the slits, the (Bragg) angular diffraction pattern generated by the grating can be predicted by the method of physical optics (acoustics), and can be numerically

  5. Engaging concert hall acoustics is made up of temporal envelope preserving reflections.

    PubMed

    Lokki, Tapio; Pätynen, Jukka; Tervo, Sakari; Siltanen, Samuel; Savioja, Lauri

    2011-06-01

    Strong, exciting, and engaging sound is perceived in the best concert halls. Here, it is shown that wideband early reflections that preserve the temporal envelope of sound contribute to the clear and open acoustics with strong bass. Such reflections are fused with the direct sound due to the precedence effect. In contrast, reflections that distort the temporal envelope render the sound weak and muddy because they partially break down the precedence. The presented findings are based on the earlier psychoacoustics research, and confirmed by a perceptual evaluation with six simulated concert halls that have same monaural room acoustical parameter values according to ISO3382-1. PMID:21682356

  6. Eleutherodactylus frogs show frequency but no temporal partitioning: implications for the acoustic niche hypothesis

    PubMed Central

    2014-01-01

    Individuals in acoustic communities compete for the use of the sound resource for communication, a problem that can be studied as niche competition. The acoustic niche hypothesis presents a way to study the partitioning of the resource, but the studies have to take into account the three dimensions of this niche: time, acoustic frequency, and space. I used an Automated Digital Recording System to determine the partitioning of time and acoustic frequency of eight frogs of the genus Eleutherodactylus from Puerto Rico. The calling activity was measured using a calling index. The community exhibited no temporal partitioning since most species called at the same time, between sunset and midnight. The species partitioned the acoustic frequency of their signals, which, in addition to the microhabitat partitioning, can provide some insight into how these species deal with the problem. This data also suggest that monitoring projects with this group should take place only before midnight to avoid false negatives. PMID:25101228

  7. Finding Spatio-Temporal Patterns in Earth Science Data

    Microsoft Academic Search

    Pang-Ning Tan; Michael Steinbach; Vipin Kumar; Christopher Potter; Steven Klooster; Alicia Torregrosa

    2001-01-01

    This paper presents preliminary work in using data mining techniques to find interesting spatio-temporal patterns from Earth Science data. The data consists of time series measurements for various Earth science and climate variables (e.g. soil moisture, temperature, and precipitation), along with additional data from existing ecosystem models (e.g. Net Primary Production). The ecological patterns of interest include associations, clusters, predictive

  8. Learning of spatial and temporal patterns in sequential hand movements

    Microsoft Academic Search

    Daeyeol Lee

    2000-01-01

    Speed and accuracy in performing a complex movement sequence improve with practice. To examine how the temporal and spatial patterns of movement sequence are learned, the sequence of target locations and the consistency in the timing of target presentation were manipulated independently while subjects produced a series of visually guided hand movements. When the sequence of target locations and the

  9. Spatio-temporal Pattern Formation in Reaction-Diffusion Systems

    E-print Network

    Mocenni, Chiara

    Spatio-temporal Pattern Formation in Reaction-Diffusion Systems Chiara Mocenni January 15, 2013 #12 without diffusion By nondimensionalization and discarding diffusion, we have the following system is the wave number. #12;Diffusion-Driven Instability c = f (c) c Rn (R) #12;Diffusion-Driven Instability c

  10. Spatial Patterns and Temporal Trajectories of the Bog Ground Layer

    E-print Network

    Benscoter, Brian W.

    Spatial Patterns and Temporal Trajectories of the Bog Ground Layer Along a Post-Fire Chronosequence in boreal bogs, wildfire selectively removes the ground layer vegetation, creating heterogeneous habitat along a chronosequence of post-fire bogs (1­105 years since fire) in north central Alberta, Canada. We

  11. TIME SERIES DATAMINING: IDENTIFYING TEMPORAL PATTERNS FOR CHARACTERIZATIONAND

    E-print Network

    Povinelli, Richard J.

    TIME SERIES DATAMINING: IDENTIFYING TEMPORAL PATTERNS FOR CHARACTERIZATIONAND PREDICTION OF TIME favorite topic, Time Series Data Mining, and on his, Fuzzy Optimal Control. I am indebted to him. #12; iv Abstract A new framework for analyzing time series data called Time Series Data Mining (TSDM

  12. A TEMPORAL PATTERN APPROACH FOR PREDICTING WEEKLY FINANCIAL TIME SERIES

    E-print Network

    Povinelli, Richard J.

    A TEMPORAL PATTERN APPROACH FOR PREDICTING WEEKLY FINANCIAL TIME SERIES DAVID H. DIGGS Department time. Times series such as the stock market are often seen as non-stationary which present challenges. The method is designed to analyze non-stationary time series and provides the basis for this work. The paper

  13. Thermal Acoustic Waves from Wall with Temporal Temperature Change

    NASA Astrophysics Data System (ADS)

    Sakaguchi, G.; Tsukamoto, M.; Sakurai, A.

    2011-05-01

    Although phenomenon of thermo-acoustic wave has been known for many years in some familiar experiences such as "singing flame" from Bunsen burner, recent trends of utilizing it for the industrial applications urge the understandings of basic details of the phenomenon itself. Here we consider, in this connection, the problem of acoustic wave generation from a particular heat source of solid wall whose temperature changes with time and the phenomenon of temperature change by standing wave oscillating in closed tube. For these we set a hollow tube whose temperature at its one end wall changes with time, and compute flow field inside using the molecular kinetic model, which is found to be more convenient for the boundary value fitting than the ordinary acoustic theory system to this problem. In practice, we use the Boltzmann equation with the BGK approximation, and compute two cases above in monotonic and sinusoidal temperature changes with time. Results of both cases show propagating density wave from the wall almost in acoustic velocity to the first case and the temperature decreases in average to the second case.

  14. a Simple Heterodyne Temporal Speckle-Pattern Interferometer

    NASA Astrophysics Data System (ADS)

    Wong, W. O.; Gao, Z.; Lu, J.

    2010-05-01

    A common light path design of heterodyne speckle pattern interferometer based on temporal speckle pattern interferometry is proposed for non-contact, full-field and real-time continuous displacement measurement. Double frequency laser is produced by rotating a half wave plate. An experiment was carried out to measure the dynamic displacement of a cantilever plate for testing the proposed common path heterodyne speckle pattern interferometer. The accuracy of displacement measurement was checked by measuring the motion at the mid-point of the plate with a point displacement sensor.

  15. THE EXPERIMENTAL INVESTIGATION OF THE SPATIO-TEMPORAL CORRELATION FUNCTIONS OF THE THERMAL ACOUSTIC RADIATION

    Microsoft Academic Search

    A. A. Anosov; Yu. N. Barabanenkov; A. G. Selskiy

    The spatio-temporal correlation functions of pressure of the thermal acoustic radiation are measured for immovable heated sources: narrow plasticine plate, two narrow parallel plasticine plates and broad plasticine plate. The correlation dependencies are obtained with multiplication of signals (measured with two receivers) shifted with time delay. The functions oscillate (the oscillation period is defined by mean reception frequency, amplitude envelope

  16. Cannabinoid Receptor Activation Shifts Temporally Engendered Patterns of Dopamine Release

    PubMed Central

    Oleson, Erik B; Cachope, Roger; Fitoussi, Aurelie; Tsutsui, Kimberly; Wu, Sharon; Gallegos, Jacqueline A; Cheer, Joseph F

    2014-01-01

    The ability to discern temporally pertinent environmental events is essential for the generation of adaptive behavior in conventional tasks, and our overall survival. Cannabinoids are thought to disrupt temporally controlled behaviors by interfering with dedicated brain timing networks. Cannabinoids also increase dopamine release within the mesolimbic system, a neural pathway generally implicated in timing behavior. Timing can be assessed using fixed-interval (FI) schedules, which reinforce behavior on the basis of time. To date, it remains unknown how cannabinoids modulate dopamine release when responding under FI conditions, and for that matter, how subsecond dopamine release is related to time in these tasks. In the present study, we hypothesized that cannabinoids would accelerate timing behavior in an FI task while concurrently augmenting a temporally relevant pattern of dopamine release. To assess this possibility, we measured subsecond dopamine concentrations in the nucleus accumbens while mice responded for food under the influence of the cannabinoid agonist WIN 55?212-2 in an FI task. Our data reveal that accumbal dopamine concentrations decrease proportionally to interval duration—suggesting that dopamine encodes time in FI tasks. We further demonstrate that WIN 55?212-2 dose-dependently increases dopamine release and accelerates a temporal behavioral response pattern in a CB1 receptor-dependent manner—suggesting that cannabinoid receptor activation modifies timing behavior, in part, by augmenting time-engendered patterns of dopamine release. Additional investigation uncovered a specific role for endogenous cannabinoid tone in timing behavior, as elevations in 2-arachidonoylglycerol, but not anandamide, significantly accelerated the temporal response pattern in a manner akin to WIN 55?212-2. PMID:24345819

  17. Biodiversity, productivity and the temporal stability of productivity: patterns and processes

    E-print Network

    Wilsey, Brian J.

    LETTER Biodiversity, productivity and the temporal stability of productivity: patterns. Additionally, we tested whether biodiversity, productivity and temporal stability were similarly influenced that favoured unproductive species increased both biodiversity and temporal stability. Species interactions

  18. Acoustical Survey of Methane Plumes on North Hydrate Ridge: Constraining Temporal and Spatial Characteristics.

    NASA Astrophysics Data System (ADS)

    Kannberg, P. K.; Trehu, A. M.

    2008-12-01

    While methane plumes associated with hydrate formations have been acoustically imaged before, little is known about their temporal characteristics. Previous acoustic surveys have focused on determining plume location, but as far as we know, multiple, repeated surveys of the same plume have not been done prior to the survey presented here. In July 2008, we acquired sixteen identical surveys within 19 hours over the northern summit of Hydrate Ridge in the Cascadia accretionary complex using the onboard 3.5 and 12 kHz echosounders. As in previous studies, the plumes were invisible to the 3.5 kHz echosounder and clearly imaged with 12 kHz. Seafloor depth in this region is ~600 m. Three distinct plumes were detected close to where plumes were located by Heeschen et al. (2003) a decade ago. Two of the plumes disappeared at ~520 m water depth, which is the depth of the top of the gas hydrate stability as determined from CTD casts obtained during the cruise. This supports the conclusion of Heeschen et al. (2003) that the bubbles are armored by gas hydrate and that they dissolve in the water column when they leave the hydrate stability zone. One of the plumes near the northern summit, however, extended through this boundary to at least 400 m (the shallowest depth recorded). A similar phenomenon was observed in methane plumes in the Gulf of Mexico, where the methane was found to be armored by an oil skin. In addition to the steady plumes, two discrete "burps" were observed. One "burp" occurred approximately 600 m to the SSW of the northern summit. This was followed by a second strong event 300m to the north an hour later. To evaluate temporal and spatial patterns, we summed the power of the backscattered signal in different depth windows for each survey. We present the results as a movie in which the backscatter power is shown in map view as a function of time. The surveys encompassed two complete tidal cycles, but no correlation between plume location or intensity and tides is apparent in the data. Additional analyses will constrain plume strength as a function of water depth. Heeschen et al., GRL, v. 30, 2003.

  19. 1987 wet deposition temporal and spatial patterns in North America

    SciTech Connect

    Simpson, J.C.; Olsen, A.R.

    1990-03-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. The report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Data are from the Acid Deposition System (ADS) for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network (NADP/NTN), the MAP3S precipitation chemistry network, the Utility Acid Precipitation Study Program (UAPSP), the Canadian Precipitation Monitoring Network (CAPMoN), and the daily and 4-weekly Acidic Precipitation in Ontario Study (APIOS-D and APIOS-C). Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1987 annual, winter, and summer periods. The temporal pattern analyses use a subset of 39 sites over a 9-year (1979--1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982--1987) period. 68 refs., 15 figs., 15 tabs.

  20. Fault diagnosis of internal combustion engines using visual dot patterns of acoustic and vibration signals

    Microsoft Academic Search

    Jian-Da Wu; Chao-Qin Chuang

    2005-01-01

    An investigation of the fault diagnosis technique in internal combustion engines based on the visual dot pattern of acoustic and vibration signals is presented in this paper. Acoustic emissions and vibration signals are well known as being able to be used for monitoring the conditions of rotating machineries. Most of the conventional methods for fault diagnosis using acoustic and vibration

  1. Spatial-temporal coherence of acoustic signals propagating in a refractive, turbulent atmosphere.

    PubMed

    Ostashev, Vladimir E; Wilson, D Keith; Vecherin, Sergey N; Collier, Sandra L

    2014-11-01

    Propagation of acoustic signals above an impedance ground in a refractive, turbulent atmosphere with spatial-temporal fluctuations in temperature and wind velocity is considered. Starting from a parabolic equation, and using the Markov approximation and a locally frozen turbulence hypothesis, closed-form equations for the spatial-temporal statistical moments of arbitrary order of the sound-pressure field are derived. The general theory provides a basis for analysis of many statistical characteristics of broadband and narrowband acoustic signals for different geometries of propagation: line-of-sight propagation, multipath propagation in a refractive atmosphere above an impedance ground, and sound scattering into a refractive shadow zone. As an example of application of this theory, the spatial-temporal coherence of narrowband acoustic signals for line-of-sight propagation is calculated and analyzed. The coherence time of acoustic signals is studied numerically for meteorological conditions ranging from cloudy to sunny conditions, and with light, moderate, and strong wind. The results obtained are compared with available experimental data. PMID:25373944

  2. Temporal order and the evolution of complex acoustic signals.

    PubMed

    Gerhardt, H Carl; Humfeld, Sarah C; Marshall, Vincent T

    2007-07-22

    The evolution of complex signals may be favoured by hidden preferences or pre-existing sensory biases. Females of two species of grey treefrogs (Hyla chrysoscelis and Hyla versicolor) were tested with combinations of a conspecific advertisement call and acoustic appendages. Appendages consisted of aggressive calls and segments of advertisement calls from conspecific males and males of three other species and bursts of filtered noise. When a wide variety of these acoustic appendages followed the advertisement call, the resulting compound signal was often more attractive than the same advertisement call alone. When the same appendages led advertisement calls, however, the compound signal was never more attractive and sometimes less attractive. The order effect was especially strong in tests of H. versicolor in which advertisement-call duration was decreased. These results cannot be explained by a general pre-existing bias for extra stimulation per se. Rather, order and other effects may constrain the evolution and subsequent modification of complex and extravagant signals, examples of which have been reported for a wide range of taxa. PMID:17507330

  3. Odor identity influences tracking of temporally patterned plumes in Drosophila

    PubMed Central

    2011-01-01

    Background Turbulent fluid landscapes impose temporal patterning upon chemical signals, and the dynamical neuronal responses to patterned input vary across the olfactory receptor repertoire in flies, moths, and locusts. Sensory transformations exhibit low pass filtering that ultimately results in perceptual fusion of temporally transient sensory signals. For example, humans perceive a sufficiently fast flickering light as continuous, but the frequency threshold at which this fusion occurs varies with wavelength. Although the summed frequency sensitivity of the fly antenna has been examined to a considerable extent, it is unknown how intermittent odor signals are integrated to influence plume tracking behavior independent of wind cues, and whether temporal fusion for behavioral tracking might vary according to the odor encountered. Results Here we have adopted a virtual reality flight simulator to study the dynamics of plume tracking under different experimental conditions. Flies tethered in a magnetic field actively track continuous (non-intermittent) plumes of vinegar, banana, or ethyl butyrate with equal precision. However, pulsing these plumes at varying frequency reveals that the threshold rate, above which flies track the plume as if it were continuous, is unique for each odorant tested. Thus, the capability of a fly to navigate an intermittent plume depends on the particular odorant being tracked during flight. Finally, we measured antennal field potential responses to an intermittent plume, found that receptor dynamics track the temporal pattern of the odor stimulus and therefore do not limit the observed behavioral temporal fusion limits. Conclusions This study explores the flies' ability to track odor plumes that are temporally intermittent. We were surprised to find that the perceptual critical fusion limit, determined behaviorally, is strongly dependent on odor identity. Antennal field potential recordings indicate that peripheral processing of temporal cues faithfully follow rapid odor transients above the rates that can be resolved behaviorally. These results indicate that (1) higher order circuits create a perceptually continuous signal from an intermittent sensory one, and that (2) this transformation varies with odorant rather than being constrained by sensory-motor integration, thus (3) offering an entry point for examining the mechanisms of rapid olfactory decision making in an ecological context. PMID:21708035

  4. Music Perception with Temporal Cues in Acoustic and Electric Hearing

    Microsoft Academic Search

    Ying-Yee Kong; Rachel Cruz; J. Ackland Jones; Fan-Gang Zeng

    2004-01-01

    Design: Both normal-hearing and cochlear implant listeners participated in the experiments. Tempo discrimination was measured in a two-interval forced-choice procedure in which subjects were asked to choose the faster tempo at four standard tempo conditions (60, 80, 100, and 120 beats per minute). For rhythmic pattern identification, seven different rhythmic patterns were created and sub- jects were asked to read

  5. Speaker recognition with temporal cues in acoustic and electric hearing

    NASA Astrophysics Data System (ADS)

    Vongphoe, Michael; Zeng, Fan-Gang

    2005-08-01

    Natural spoken language processing includes not only speech recognition but also identification of the speaker's gender, age, emotional, and social status. Our purpose in this study is to evaluate whether temporal cues are sufficient to support both speech and speaker recognition. Ten cochlear-implant and six normal-hearing subjects were presented with vowel tokens spoken by three men, three women, two boys, and two girls. In one condition, the subject was asked to recognize the vowel. In the other condition, the subject was asked to identify the speaker. Extensive training was provided for the speaker recognition task. Normal-hearing subjects achieved nearly perfect performance in both tasks. Cochlear-implant subjects achieved good performance in vowel recognition but poor performance in speaker recognition. The level of the cochlear implant performance was functionally equivalent to normal performance with eight spectral bands for vowel recognition but only to one band for speaker recognition. These results show a disassociation between speech and speaker recognition with primarily temporal cues, highlighting the limitation of current speech processing strategies in cochlear implants. Several methods, including explicit encoding of fundamental frequency and frequency modulation, are proposed to improve speaker recognition for current cochlear implant users.

  6. Intermodal transfer in temporal discrimination. [of visual and acoustic stimuli duration

    NASA Technical Reports Server (NTRS)

    Warm, J. S.; Stutz, R. M.; Vassolo, P. A.

    1975-01-01

    This study determined if training for accuracy in temporal discrimination would transfer across sensory modalities. A fractionation method was used in which subjects bisected the durations of acoustic and visual signals at three standard intervals (6, 12, and 18 sec). Absolute error was the performance index. Half of the subjects were trained with acoustic stimuli and then tested in vision; the remainder were trained in vision and tested in audition. Similar negatively accelerated acquisition functions were noted for both modalities. Positive intermodal transfer, characterized by symmetry across modalities, was obtained at all standard durations. The results were considered to provide support for the notion that a common mechanism underlies temporal discriminations in different sensory systems.

  7. Spatial and temporal patterns of Cenozoic dynamic topography around Australia

    NASA Astrophysics Data System (ADS)

    Czarnota, K.; Hoggard, M. J.; White, N.; Winterbourne, J.

    2013-03-01

    Despite its importance, the spatial and temporal pattern of dynamic topography generated by mantle convective circulation is poorly known. We present accurate estimates of dynamic topography from oceanic basins and continental margins surrounding Australia. Our starting point is measurement of residual depth anomalies on the oldest oceanic floor adjacent to the continental shelf. These anomalies were determined from a combined dataset of ~200 seismic reflection and wide-angle images of well-sedimented oceanic crust. They have amplitudes of between -1 km and +0.5 km, and their spatial variation is broadly consistent with long-wavelength free-air gravity and shallow seismic tomographic anomalies. Along the Northwest Shelf, a regional depth anomaly of -300 to -700 m intersects the adjacent continental shelf. The temporal evolution of this anomaly was determined by analyzing the stratigraphic architecture of an extensive carbonate platform, which fringes the shelf and records a dramatic switch from progradation to aggradation during Neogene times. Three-dimensional seismic mapping calibrated by boreholes was used to calculate water-loaded subsidence histories at rollover points of clinoforms along the shelf. At 9 ± 3 Ma, the rate of subsidence increases from 5 to up 75 m Myr-1, generating a subsidence anomaly of -300 to -700 m. The amplitude of this anomaly varies along the shelf and cannot be generated by glacio-eustatic sea-level variation. Instead, we propose that a regional subsidence episode, which affects both the proximal shelf and the distal oceanic basin, was generated by convective drawdown. By combining our results with other published estimates of uplift and subsidence, a map of Australia, which shows the spatial and temporal pattern of dynamic topography is presented. Most, but not all, of Australia's epeirogeny can be attributed to rapid northward motion of the Australian plate over a pre-existing pattern of convective circulation.

  8. Inferring Synaptic Connectivity from Spatio-Temporal Spike Patterns

    PubMed Central

    Van Bussel, Frank; Kriener, Birgit; Timme, Marc

    2011-01-01

    Networks of well-known dynamical units but unknown interaction topology arise across various fields of biology, including genetics, ecology, and neuroscience. The collective dynamics of such networks is often sensitive to the presence (or absence) of individual interactions, but there is usually no direct way to probe for their existence. Here we present an explicit method for reconstructing interaction networks of leaky integrate-and-fire neurons from the spike patterns they exhibit in response to external driving. Given the dynamical parameters are known, the approach works well for networks in simple collective states but is also applicable to networks exhibiting complex spatio-temporal spike patterns. In particular, stationarity of spiking time series is not required. PMID:21344004

  9. A temporal fourth-order scheme for the first-order acoustic wave equations

    NASA Astrophysics Data System (ADS)

    Long, Guihua; Zhao, Yubo; Zou, Jun

    2013-09-01

    In this paper, we propose a temporal fourth-order scheme for solving the 2-D first-order acoustic wave equations with perfectly matched layers in time domain. For the temporal discretization, we approximate the velocity at mid-points and the pressure at grid points, then expand the velocity and pressure by Taylor series and replace the high-order temporal derivatives by spatial derivatives. For the spatial discretization, we apply the Fourier pseudospectral method based on conventional and staggered-grid schemes. The dispersion and stability of the new scheme are analysed, and numerical simulations are presented to confirm the robustness and efficiency of the scheme. The new scheme is eventually applied for the wavefield modelling and reverse time migration in bilayered and heterogeneous media to further verify its accuracy and efficiency.

  10. Gender and the lateral angle of the internal acoustic canal meatus as measured on computerized tomography of the temporal bone

    Microsoft Academic Search

    Gur Akansel; Nagihan Inan; Omer Kurtas; H. Tahsin Sarisoy; Arzu Arslan; Ali Demirci

    2008-01-01

    IntroductionCadaveric studies yielded promising results in sexing the temporal bones by measuring the lateral angle of the internal acoustic canal meatus. In this study, we evaluated the capability of computerized tomography of the temporal bone to reproduce these results.

  11. Spatio-Temporal Patterns in the Depth EEG During the Epileptic Seizure

    Microsoft Academic Search

    Jung Ae Kim; Sunyoung Cho; Sang-kun Lee; Hyunwoo Nam; Seung Kee Han

    2005-01-01

    \\u000a We analyzed the spatio-temporal patterns of the depth EEG recorded from a patient with lateral temporal-lobe epilepsy. Statistical\\u000a analysis based on the Jensen-Shannon entropy (JS-E) as well as linear power spectral analyses were performed. The spatio-temporal\\u000a patterns from JS-E and ? rhythm successfully detected the onset timing of the seizure and revealed the temporal topology of the epileptic focus. The

  12. Comparison of acoustic and net sampling systems to determine patterns in zooplankton distribution

    E-print Network

    Pierce, Stephen

    Comparison of acoustic and net sampling systems to determine patterns in zooplankton distribution distributions of zooplankton that were resolved acoustically were not apparent within the integrated depth strata of the individual MOCNESS net samples. The taxonomic and size composition of the zooplankton

  13. Temporal patterns in adult salmon migration timing across southeast Alaska.

    PubMed

    Kovach, Ryan P; Ellison, Stephen C; Pyare, Sanjay; Tallmon, David A

    2015-05-01

    Pacific salmon migration timing can drive population productivity, ecosystem dynamics, and human harvest. Nevertheless, little is known about long-term variation in salmon migration timing for multiple species across broad regions. We used long-term data for five Pacific salmon species throughout rapidly warming southeast Alaska to describe long-term changes in salmon migration timing, interannual phenological synchrony, relationships between climatic variation and migratory timing, and to test whether long-term changes in migration timing are related to glaciation in headwater streams. Temporal changes in the median date of salmon migration timing varied widely across species. Most sockeye populations are migrating later over time (11 of 14), but pink, chum, and especially coho populations are migrating earlier than they did historically (16 of 19 combined). Temporal trends in duration and interannual variation in migration timing were highly variable across species and populations. The greatest temporal shifts in the median date of migration timing were correlated with decreases in the duration of migration timing, suggestive of a loss of phenotypic variation due to natural selection. Pairwise interannual correlations in migration timing varied widely but were generally positive, providing evidence for weak region-wide phenological synchrony. This synchrony is likely a function of climatic variation, as interannual variation in migration timing was related to climatic phenomenon operating at large- (Pacific decadal oscillation), moderate- (sea surface temperature), and local-scales (precipitation). Surprisingly, the presence or the absence of glaciers within a watershed was unrelated to long-term shifts in phenology. Overall, there was extensive heterogeneity in long-term patterns of migration timing throughout this climatically and geographically complex region, highlighting that future climatic change will likely have widely divergent impacts on salmon migration timing. Although salmon phenological diversity will complicate future predictions of migration timing, this variation likely acts as a major contributor to population and ecosystem resiliency in southeast Alaska. PMID:25482609

  14. Measurement resolution of noise directivity patterns from acoustic flight tests

    NASA Technical Reports Server (NTRS)

    Conner, David A.

    1989-01-01

    The measurement resolution of noise directivity patterns from acoustic flight tests was investigated. Directivity angle resolution is affected by the data reduction parameters, the aircraft velocity and flyover altitude, and by deviations of the aircraft from the desired flight path. Equations are developed which determine bounds for the lateral and longitudinal directivity angle resolution as a function of the nominal directivity angle. The equations are applied to a flight test data base and the effects of several flight conditions and data reduction parameters on the directivity angle resolution are presented. The maximum directivity angle resolution typically occurs when the aircraft is at or near the overhead position. In general, directivity angle resolution improves with decreasing velocity, increasing altitude, increasing sampling rate, decreasing block size, and decreasing block averages. Deviations from the desired ideal flight path will increase the resolution. For the flight experiment considered in this study, an average of two flyovers were required at each test condition to obtain an acceptable flight path. The ability of the pilot to maintain the flight track improved with decreasing altitude, decreasing velocity, and practice. Due to the prevailing wind conditions, yaw angles of as much as 20 deg were required to maintain the desired flight path.

  15. Temporal Patterns of Fire in West Kalimantan, Indonesia

    NASA Astrophysics Data System (ADS)

    Murphy, K. J.

    2004-12-01

    Fire is an essential landscape management tool extensively employed in West Kalimantan Indonesia to clear land and prepare agricultural areas. Under typically wet climatic conditions fires are easily controlled and seldom spread into adjacent land cover. However, during droughts induced by strong El Nino events, land management fires threaten vast areas of the landscape threatening endangered species habitat and releasing large amounts of carbon into the atmosphere. This study investigates temporal and spatial variations of fires detected by Moderate-resolution Imaging Spectroradiometer (MODIS) and Along Track Scanning Radiometer between 2000 and 2004 against the MODIS Vegetation Continuous Fields and cultural features manually digitized from Landsat ETM+ scenes. Patterns of fire during phases of the El Niño-La Niña cycle are described and the impacts of fires on orangutan habitat are investigated.

  16. Temporal and spatial patterns of pan evaporation in South Korea

    NASA Astrophysics Data System (ADS)

    Jeon, S.; Ryu, Y.

    2012-12-01

    Pan evaporation determines atmospheric demand for evaporation. Several studies reported the decrease of pan evaporation in China in conjunction with global dimming in last several decades. In this study, we investigate the temporal and spatial patterns of pan evaporation measured at 16 stations in South Korea. The data records span 20 to 40 years and we conducted the trend analysis from 1973. We found that pan evaporation has decreased -1.47 mm yr-2 (p<0.05). Solar radiation has increased which does not indicate global dimming. Wind speed has decreased, which was the main factor that decreased pan evaporation. We found that reduction in pan evaporation was stronger in summer and coastal areas. The reduction of pan evaporation was similar in South Korea and China, but with different reasons. Thorough attribution of the reduction in pan evaporation is discussed.

  17. The BMP signaling gradient patterns dorsoventral tissues in a temporally progressive manner along the anteroposterior axis

    PubMed Central

    Tucker, Jennifer A.; Mintzer, Keith A.; Mullins, Mary C.

    2008-01-01

    Summary Patterning of the vertebrate anteroposterior (AP) axis proceeds temporally from anterior to posterior. How dorsoventral (DV) axial patterning relates to AP temporal patterning is unknown. We examined the temporal activity of BMP signaling in patterning ventrolateral cell fates along the AP axis, using transgenes that rapidly turn ‘off’ or ‘on’ BMP signaling. We show that BMP signaling patterns rostral DV cell fates at the onset of gastrulation, while progressively more caudal DV cell fates are patterned at progressively later intervals during gastrulation. Increased BMP signal duration is not required to pattern more caudal DV cell fates, rather distinct temporal intervals of signaling are required. This progressive action is regulated downstream of, or in parallel to BMP signal transduction at the level of Smad1/5 phosphorylation. We propose that a temporal cue regulates a cell's competence to respond to BMP signaling, allowing the acquisition of a cell's DV and AP identity simultaneously. PMID:18194657

  18. Temporal integration of the acoustic-reflex threshold and its age-related changes

    NASA Astrophysics Data System (ADS)

    Emmer, Michele Bonnie

    2000-08-01

    This study investigated age-related effects and changes on temporal integration of the acoustic-reflex threshold (ART) for broad-band noise (BBN) and 1000-Hz tonal activators. There were forty subjects comprised of 20 young adults (10 females and 10 males) and 20 older adults (10 females and 10 males). For both activating stimuli, temporal integration of the ART was investigated using 1-dB intensity increments and a high-resolution strip-chart recorder for the following activating stimulus durations: 12 msec, 25 msec, 50 msec, 100 msec, 200 msec, 300 msec, 500 msec, and 1000 msec. Temporal integration for both BBN and 1000-Hz tonal stimulus activators was analyzed using analysis of variance (ANOVA), analysis of covariance (ANCOVA), and analysis of trend. The results indicated the absence of a significant age-related effect on temporal integration of the ART for the 1000-Hz tonal activator. In contrast, a significant age-related effect was present for temporal integration of the ART for the BBN activator. This age- related effect for temporal integration for the BBN activator was observed at activator stimulus durations of over 200 msec. The absence of an age-related effect for temporal integration for the tonal activator, and its presence for the BBN activator, were explained primarily in relation to age-related changes of the outer-hair cells (OHCs) which are known to be first affected by age. This change in the OHCs was theorized to be the major factor for the age-related effects on the BBN ART. Clinical and research data were presented to support this hypothesis.

  19. Acoustic Waves and Farfield Patterns in Two Dimensional Oceans with Porouselastic Seabeds

    E-print Network

    Acoustic Waves and Far­field Patterns in Two Dimensional Oceans with Porous­elastic Seabeds R. P dimensional oceans with porous­elastic seabeds. First we outline our results developed for three dimensional

  20. Spatial and temporal patterns of hydrological extremes in Europe

    NASA Astrophysics Data System (ADS)

    Hall, Julia; Perdigão, Rui A. P.

    2015-04-01

    At a catchment scale, the hydrological characteristics of extreme events such as floods and droughts vary considerably across Europe. However, extreme events are also governed by large-scale physical processes that can influence the hydrological response of larger regions beyond catchment or national boundaries. To analyse such extreme events at a regional scale, a hydrological database for Europe, consisting of daily data from over 5000 stations, has been assembled. The database is a result of existing datasets of European coverage amended and complemented by a collaborative effort as part of a joint European flood research agreement based on the exchange of data, models, staff and expertise. The developed database allows an analysis of the influence of large scale drivers such as climate on the spatial patterns of floods and droughts across Europe. The timing of extreme events in Europe is a key variable in understanding the main processes governing flood and drought events. In this contribution, regional similarities and differences of hydrological extremes in Europe are analysed and the resulting characteristic spatio-temporal patterns of floods and droughts are presented separately and compared with one another.

  1. Statistical methods for investigating quiescence and other temporal seismicity patterns

    USGS Publications Warehouse

    Matthews, M.V.; Reasenberg, P.A.

    1988-01-01

    We propose a statistical model and a technique for objective recognition of one of the most commonly cited seismicity patterns:microearthquake quiescence. We use a Poisson process model for seismicity and define a process with quiescence as one with a particular type of piece-wise constant intensity function. From this model, we derive a statistic for testing stationarity against a 'quiescence' alternative. The large-sample null distribution of this statistic is approximated from simulated distributions of appropriate functionals applied to Brownian bridge processes. We point out the restrictiveness of the particular model we propose and of the quiescence idea in general. The fact that there are many point processes which have neither constant nor quiescent rate functions underscores the need to test for and describe nonuniformity thoroughly. We advocate the use of the quiescence test in conjunction with various other tests for nonuniformity and with graphical methods such as density estimation. ideally these methods may promote accurate description of temporal seismicity distributions and useful characterizations of interesting patterns. ?? 1988 Birkha??user Verlag.

  2. Niche Overlap and Temporal Activity Patterns of Social Wasps (Hymenoptera: Vespidae) in a Brazilian Cashew Orchard

    E-print Network

    Willig, Michael

    Niche Overlap and Temporal Activity Patterns of Social Wasps (Hymenoptera: Vespidae) in a Brazilian as a glucidic resource by wasps was quantified in an orchard to evaluate temporal overlap for a species-rich guild of social wasps and to determine if temporal partitioning within this guild reduces competition

  3. Spatio-temporal correlation of vegetation and temperature patterns

    NASA Astrophysics Data System (ADS)

    Coppola, R.; D'Emilio, M.; Imbrenda, V.; Lanfredi, M.; Macchiato, M.; Simoniello, T.

    2010-05-01

    Temperature is one of the variables largely influencing vegetation species distributions (biogeographical regions) and plant development (phenological cycle). Anomalies in temperature regional patterns and in microclimate conditions induce modifications in vegetation cover phenology; in particular in European regions, the responsiveness of vegetation to temperature increase is greater in warmer Mediterranean countries. In order to assess the spatial arrangement and the temporal variability of vegetation and temperature patterns in a typical Mediterranean environment, we investigated monthly NDVI-AVHRR and temperature time series over Southern Italy, core of Mediterranean Basin. Temperature data, obtained from 35 meteoclimatic stations, were rasterized by adopting a combined deterministic-stochastic procedure we suitably implemented for the investigated region in order to obtain spatial data comparable with NDVI maps. For the period 1996-1998, monthly MVC data were clusterized on annual basis by means of a classification procedure to aggregate areas with similar phenological cycles. The same procedure was adopted to jointly evaluate temperature and vegetation profiles and identify areas having similar phenological and temperature patterns. The comparison of the identified clusters showed that the classification obtained with and without temperature profiles are very similar enhancing the strong role of this variable in vegetation development. Some exceptions in the cluster arrangement are due to local anomalies in vegetation distribution, such as forest fires. In order to spatially analyze such a dependence, we also elaborated a time correlation map for each year and we found that the correlation patterns are persistent on the year basis and generally follow the land cover distributions. The correlation values are very high and positive for the forested mountainous areas (R>0.8), whereas they are negative for plan coastal areas (R<-0.8). Low correlation values (R= -0.4/0.4) were found for the transitional zones and agricultural areas mainly dominated by irrigated herbaceous cultivations. On average, in southern Italy the analysis showed a strong dependence of NDVI and temperature profiles during the spring and summer time (greening period) and a reduced responsiveness in autumn when precipitations control the vegetation recovery after the water shortage period.

  4. QueryMarvel: A visual query language for temporal patterns using comic strips

    Microsoft Academic Search

    Jing Jin; Pedro A. Szekely

    2009-01-01

    In many domains, decision makers want to find and understand patterns of events as these patterns often give insight into the causal relationships among events. Current systems to specify patterns are either too difficult to use or only support simple patterns. We present QueryMarvel, an interactive visual query environment that allows ordinary users to easily and efficiently specify complex temporal

  5. Macroscale Circulation Patterns as Reflected in Spatial and Temporal Patterns of Precipitation over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Conselyea, K.; Yin, Z.

    2007-12-01

    Circulation patterns such as the NAO, PNA, and AO have been known to impact climate both near the action centers and at great distances away. These macroscale circulation patterns can impact regional wind patterns, temperature gradients and pressure gradients. Changes in these gradients can cause an onset of various weather conditions including precipitation. Precipitation across the Tibetan Plateau is influenced by known phenomena such as monsoon systems and teleconnections. Previous studies have suggested that other forcing mechanisms also may play a vital role in influencing precipitation in this region. To evaluate potential forcing factors affecting precipitation across the Tibetan Plateau, the relationship between the spatial and temporal patterns of precipitation and the regional and macroscale circulation patterns will be investigated. To explore this relationship statistical analysis, such as Principal Component Analysis (PCA), Correlation Field Analysis, and Canonical Correspondence Analysis (CCA), is preformed. This study also incorporates tree ring chronologies from Qilian junipers (Sabina przewalskii Kom.) sampled in the Qaidam Basin, northeastern Tibetan Plateau. These data have been used in previous studies to indicate environmental change, and tree rings taken from this region have shown signatures of circulation patterns such as Arctic Oscillation (AO). Based on the relationship between tree ring data and circulation patterns it is possible to reconstruct past events. This information along with examination of National Centers for Environmental Protection/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis data will aid in the examination of the relationship between teleconnection patterns and precipitation, and develop a greater understanding of the precipitation variability across the Tibetan Plateau.

  6. Detection of spatio-temporal change of ocean acoustic velocity for observing seafloor crustal deformation applying seismological methods

    NASA Astrophysics Data System (ADS)

    Eto, S.; Nagai, S.; Tadokoro, K.

    2011-12-01

    Our group has developed a system for observing seafloor crustal deformation with a combination of acoustic ranging and kinematic GPS positioning techniques. One of the effective factors to reduce estimation error of submarine benchmark in our system is modeling variation of ocean acoustic velocity. We estimated various 1-dimensional velocity models with depth under some constraints, because it is difficult to estimate 3-dimensional acoustic velocity structure including temporal change due to our simple acquisition procedure of acoustic ranging data. We, then, applied the joint hypocenter determination method in seismology [Kissling et al., 1994] to acoustic ranging data. We assume two conditions as constraints in inversion procedure as follows: 1) fixed acoustic velocity in deeper part because it is usually stable both in space and time, 2) each inverted velocity model should be decreased with depth. The following two remarkable spatio-temporal changes of acoustic velocity 1) variations of travel-time residuals at the same points within short time and 2) larger differences between residuals at the neighboring points, which are one's of travel-time from different benchmarks. The First results cannot be explained only by the effect of atmospheric condition change including heating by sunlight. To verify the residual variations mentioned as the second result, we have performed forward modeling of acoustic ranging data with velocity models added velocity anomalies. We calculate travel time by a pseudo-bending ray tracing method [Um and Thurber, 1987] to examine effects of velocity anomaly on the travel-time differences. Comparison between these residuals and travel-time difference in forward modeling, velocity anomaly bodies in shallower depth can make these anomalous residuals, which may indicate moving water bodies. We need to apply an acoustic velocity structure model with velocity anomaly(s) in acoustic ranging data analysis and/or to develop a new system with a large number of sea surface stations to detect them, which may be able to reduce error of seafloor benchmarker position.

  7. Characterizing temporal patterns in the swimming activity of Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Choi, Yeontaek; Jeon, Wonju; Kang, Seung-Ho; Lee, Sang-Hee; Chon, Tae-Soo

    2012-06-01

    The locomotion behavior of Caenorhabditis elegans has been studied extensively to understand the respective roles of neural control and biomechanics as well as the interaction between them. In the present study, we suggest a new approach to characterize the temporal patterns in the swimming behavior of the organism. The approach is based on the branching length similarity (BLS) entropy defined on a simple branching network consisting of a single node and branches. The organism's swimming activity is recorded using a charge-coupled device (CCD) camera for 3 h at a rate of 4 frames per second. In each frame, we place 13 points as nodes, those points being distributed at equal intervals along the organism's length. Thus, the organism is represented by 13 nodes and 12 edges between nodes. By using the nodes and edges, we construct two simple networks. One is formed by connecting the center point to all other points, and the other is generated from the angles between edges. The BLS entropy values are calculated as S L for the former network and S ? for the latter. We investigate the distributions of the S L and the S ? values in the phase space of S L — S ? and compare those with the values obtained from a simulated C. elegans generated by using randomly-moving chained particles along a certain angle. The comparison revealed distinctive features of the movement patterns of C. elegans during swimming activity. In addition, we briefly discuss the application of our method to bio-monitoring systems to capture behavioral changes of test organisms before and after chemical treatment at low concentrations.

  8. Spatial and Temporal Patterns of Global Onshore Wind Speed Distribution

    SciTech Connect

    Zhou, Yuyu; Smith, Steven J.

    2013-09-09

    Wind power, a renewable energy source, can play an important role in electrical energy generation. Information regarding wind energy potential is important both for energy related modeling and for decision-making in the policy community. While wind speed datasets with high spatial and temporal resolution are often ultimately used for detailed planning, simpler assumptions are often used in analysis work. An accurate representation of the wind speed frequency distribution is needed in order to properly characterize wind energy potential. Using a power density method, this study estimated global variation in wind parameters as fitted to a Weibull density function using NCEP/CFSR reanalysis data. The estimated Weibull distribution performs well in fitting the time series wind speed data at the global level according to R2, root mean square error, and power density error. The spatial, decadal, and seasonal patterns of wind speed distribution were then evaluated. We also analyzed the potential error in wind power estimation when a commonly assumed Rayleigh distribution (Weibull k = 2) is used. We find that the assumption of the same Weibull parameter across large regions can result in substantial errors. While large-scale wind speed data is often presented in the form of average wind speeds, these results highlight the need to also provide information on the wind speed distribution.

  9. The temporal patterns of disease severity and prevalence in schistosomiasis

    NASA Astrophysics Data System (ADS)

    Ciddio, Manuela; Mari, Lorenzo; Gatto, Marino; Rinaldo, Andrea; Casagrandi, Renato

    2015-03-01

    Schistosomiasis is one of the most widespread public health problems in the world. In this work, we introduce an eco-epidemiological model for its transmission and dynamics with the purpose of explaining both intra- and inter-annual fluctuations of disease severity and prevalence. The model takes the form of a system of nonlinear differential equations that incorporate biological complexity associated with schistosome's life cycle, including a prepatent period in snails (i.e., the time between initial infection and onset of infectiousness). Nonlinear analysis is used to explore the parametric conditions that produce different temporal patterns (stationary, endemic, periodic, and chaotic). For the time-invariant model, we identify a transcritical and a Hopf bifurcation in the space of the human and snail infection parameters. The first corresponds to the occurrence of an endemic equilibrium, while the latter marks the transition to interannual periodic oscillations. We then investigate a more realistic time-varying model in which fertility of the intermediate host population is assumed to seasonally vary. We show that seasonality can give rise to a cascade of period-doubling bifurcations leading to chaos for larger, though realistic, values of the amplitude of the seasonal variation of fertility.

  10. A Regression-Based Temporal Pattern Mining Scheme for Data Streams

    Microsoft Academic Search

    Wei-guang Teng; Ming-syan Chen; Philip S. Yu

    2003-01-01

    We devise in this paper a regression-based al- gorithm, called algorithm FTP-DS (Frequent Temporal Patterns of Data Streams), to mine frequent temporal patterns for data streams. While providing a general framework of pat- tern frequency counting, algorithm FTP-DS has two major features, namely one data scan for online statistics collection and regression- based compact pattern representation .T o at- tain

  11. Generating Linear Temporal Logic Formulas for Pattern-Based Specifications

    E-print Network

    Ward, Karen

    is considered. Based on a selected pattern, SPS provides a specification for each type of scope in multiple behavior to represent pattern and scope parameters. In this work, we provide formal definitions of patterns. Each pattern describes the structure of specific behavior and defines the pattern's relationship

  12. Comparing sampling patterns for kriging the spatial mean temporal trend

    Microsoft Academic Search

    C. J. F. ter Braak; D. J. Brus; E. J. Pebesma

    2008-01-01

    In monitoring the environment one often wishes to detect the temporal trend in a variable that varies across a region. A useful\\u000a executive summary is then the temporal trend in the spatial mean. In this article, the best linear unbiased predictor of the\\u000a spatial mean temporal trend and its variance are derived under a universal kriging model. Five different, spatially

  13. Conversion of sound radiation pattern via gradient acoustic metasurface with space-coiling structure

    NASA Astrophysics Data System (ADS)

    Yuan, Baoguo; Cheng, Ying; Liu, Xiaojun

    2015-02-01

    We designed, fabricated, and experimentally demonstrated a gradient acoustic metasurface to manipulate sound radiation patterns. The gradient metasurface is constructed on the basis of a coiling-up space in a tunable interdigitated structure, which exhibits relative refractive index in a discretized classic hyperbolic secant profile. Capable of generating secondary sound sources with desired gradient phase shifts, the metasurface shows the ability of controlling sound radiation such as by cylindrical-to-plane-wave conversion, plane wave focusing, and effective tunable acoustic negative refraction. Owing to its deep-subwavelength thickness, the metasurface may reduce the size of acoustic devices and offer potential applications in imaging and scanning systems.

  14. Innovations in motoneuron synchrony drive rapid temporal modulations in vertebrate acoustic signaling

    PubMed Central

    Chagnaud, Boris P.; Zee, Michele C.; Baker, Robert

    2012-01-01

    Rapid temporal modulation of acoustic signals among several vertebrate lineages has recently been shown to depend on the actions of superfast muscles. We hypothesized that such fast events, known to require synchronous activation of muscle fibers, would rely on motoneuronal properties adapted to generating a highly synchronous output to sonic muscles. Using intracellular in vivo recordings, we identified a suite of premotor network inputs and intrinsic motoneuronal properties synchronizing the oscillatory-like, simultaneous activation of superfast muscles at high gamma frequencies in fish. Motoneurons lacked spontaneous activity, firing synchronously only at the frequency of premotor excitatory input. Population-level motoneuronal output generated a spike-like, vocal nerve volley that directly determines muscle contraction rate and, in turn, natural call frequency. In the absence of vocal output, motoneurons showed low excitability and a weak afterhyperpolarization, leading to rapid accommodation in firing rate. By contrast, vocal activity was accompanied by a prominent afterhyperpolarization, indicating a dependency on network activity. Local injection of a GABAA receptor antagonist demonstrated the necessity of electrophysiologically and immunohistochemically confirmed inhibitory GABAergic input for motoneuronal synchrony and vocalization. Numerous transneuronally labeled motoneurons following single-cell neurobiotin injection together with electrophysiological collision experiments confirmed gap junctional coupling, known to contribute to synchronous activity in other neural networks. Motoneuronal synchrony at the premotor input frequency was maintained during differential recruitment of variably sized motoneurons. Differential motoneuron recruitment led, however, to amplitude modulation (AM) of vocal output and, hence, natural call AM. In summary, motoneuronal intrinsic properties, in particular low excitability, predisposed vocal motoneurons to the synchronizing influences of premotor inputs to translate a temporal input code into a coincident and extremely synchronous, but variable-amplitude, output code. We propose an analogous suite of neuronal properties as a key innovation underlying similarly rapid acoustic events observed among amphibians, reptiles, birds, and mammals. PMID:22423004

  15. Detection of Acoustic Temporal Fine Structure by Cochlear Implant Listeners: Behavioral Results and Computational Modeling

    PubMed Central

    Imennov, Nikita S.; Won, Jong Ho; Drennan, Ward R.; Jameyson, Elyse; Rubinstein, Jay T.

    2013-01-01

    A test of within-channel detection of acoustic temporal fine structure (aTFS) cues is presented. Eight cochlear implant listeners (CI) were asked to discriminate between two Schroeder-phase (SP) complexes using a two-alternative, forced-choice task. Because differences between the acoustic stimuli are primarily constrained to their aTFS, successful discrimination reflects a combination of the subjects’ perception of and the strategy’s ability to deliver aTFS cues. Subjects were mapped with single-channel Continuous Interleaved Sampling (CIS) and Simultaneous Analog Stimulation (SAS) strategies. To compare within- and across- channel delivery of aTFS cues, a 16-channel clinical HiRes strategy was also fitted. Throughout testing, SAS consistently outperformed the CIS strategy (p ? 0.002). For SP stimuli with F0 =50 Hz, the highest discrimination scores were achieved with the HiRes encoding, followed by scores with the SAS and the CIS strategies, respectively. At 200 Hz, single-channel SAS performed better than HiRes (p = 0.022), demonstrating that under a more challenging testing condition, discrimination performance with a single-channel analog encoding can exceed that of a 16-channel pulsatile strategy. To better understand the intermediate steps of discrimination, a biophysical model was used to examine the neural discharges evoked by the SP stimuli. Discrimination estimates calculated from simulated neural responses successfully tracked the behavioral performance trends of single-channel CI listeners. PMID:23333260

  16. Acoustic chaos

    SciTech Connect

    Lauterborn, W.; Parlitz, U. [Drittes Physikalisches Institut, Universitaet Goettingen, D-37073 Goettingen (Germany); Holzfuss, J.; Billo, A. [Institut fuer Angewandte Physik, Technische Hochschule Darmstadt, D-64289 Darmstadt (Germany); Akhatov, I. [Department of Continuous Media Mechanics, Bashkir State University, Ufa 450074 (Russia)

    1996-06-01

    Acoustic cavitation, a complex, spatio-temporal dynamical system, is investigated with respect to its chaotic properties. The sound output, the {open_quote}{open_quote}noise{close_quote}{close_quote}, is subjected to time series analysis. The spatial dynamics of the bubble filaments is captured by high speed holographic cinematography and subsequent digital picture processing from the holograms. Theoretical models are put forward for describing the pattern formation. {copyright} {ital 1996 American Institute of Physics.}

  17. Intrinsic Temporal Patterning in the Spontaneous Movement of Awake Neonates.

    ERIC Educational Resources Information Center

    Robertson, Steven S.

    1982-01-01

    The temporal organization of spontaneous movement in healthy, awake neonates was studied on the second or third day after birth. Movement was recorded using time lapse photography and quantified as a function of time. Evidence of intrinsic temporal organization among subjects was found. (MP)

  18. Efficient detection of motion patterns in spatio-temporal data sets

    Microsoft Academic Search

    Joachim Gudmundsson; Marc J. van Kreveld; Bettina Speckmann

    2004-01-01

    Moving point object data can be analyzed through the discovery of patterns. We consider the computational efficiency of detecting four such spatio-temporal patterns, namely flock, leadership, convergence, and encounter, as defined by Laube et al., 2004. These patterns are large enough subgroups of the moving point objects that exhibit similar movement in the sense of direction, heading for the same

  19. Association rule mining based on spatio-temporal processes of spatial distribution patterns

    NASA Astrophysics Data System (ADS)

    Zhang, Xuewu; Su, Fenzhen; Shi, Yishao; He, Yawen

    2008-12-01

    Spatial distribution pattern is an arrangement of two or more spatial objects according to some spatial relations, such as spatial direction, topological and distance relations. In the real world, spatial objects and spatial distribution pattern all vary continuously along the time-line. Traditional spatial and non-spatial data dissevers this continuous spatio-temporal process. Under analyzing relations among spatial object, its attributes and spatial distribution pattern, we brought metaspatio- temporal process, spatio-temporal process and spatial distribution pattern spatio-temporal process. Rainfall in Eastern China has a typical spatial distribution pattern, being composed of the northern rain area and the southern rain area. Through constructing spatio-temporal process transactions, the association rules can be extracted from spatiotemporal process data set by the Apriori algorithm. The result of the spaio-temporal process association rule mining is consistent with the analysis of the theory. Finally, it is concluded that the spatio-temporal process can describe change of a spatial object in a defined time range, and change trend of one entity can be forecasted through varying trend of others based on the valuable spatio-temporal process association rules.

  20. Spatial and temporal patterns in erosion and deposition in the York River, Chesapeake Bay, VA

    NASA Astrophysics Data System (ADS)

    Rodríguez-Calderón, Cielomar; Kuehl, Steven A.

    2013-01-01

    Seasonal patterns of seabed erosion and deposition in a dynamic estuarine environment, the York River (USA), are examined through acoustic studies and seabed sampling to identify the dominant environmental controls on sediment mobility. Areas near Clay Bank in the York River were surveyed monthly using a dual-frequency sonar for a 12 month period. In addition, six stations within these areas were sampled during the surveys. Strong spatial and temporal variations of a soft mud layer were identified, providing new insight to recurring seasonal and spatial patterns in deposition and erosion in the middle reaches of the York River estuary. Sub-bottom data indicated maximum thickness (5-22 cm ± 4 cm) of the soft mud layer during spring and winter from April 2008 through March 2009. Minimum thicknesses (1-12 cm ± 4 cm) of the soft mud layer were observed during summer and fall. Maximum thickness coincided with the occurrence of the secondary turbidity maximum near Clay Bank in the York River. Spatial variations in the soft-mud layer thickness were also identified between and within the York River secondary channel, the inactive oyster reef area, the south west flank of the main channel, and the main channel. The upriver secondary channel, the south west channel flank, and the main channel areas were physically dominated. The downriver secondary channel area was biologically dominated and the inactive oyster reef area reflected both physical and biological processes. Water content trends showed no correlation with seabed stability in this area. Observed changes in soft mud thicknesses are interpreted to result from both biological and physical factors, which vary markedly between winter/spring and summer/fall seasons, and among the different environments of the estuary's channel.

  1. A GIS-based Bayesian approach for analyzing spatial-temporal patterns of traffic crashes 

    E-print Network

    Li, Linhua

    2009-06-02

    This thesis develops a GIS-based Bayesian approach for area-wide traffic crash analysis. Five years of crash data from Houston, Texas, are analyzed using a geographic information system (GIS), and spatial-temporal patterns ...

  2. Spatio-temporal foraging patterns of a giant zooplanktivore, the leatherback turtle

    Microsoft Academic Search

    Sabrina Fossette; Victoria J. Hobson; Charlotte Girard; Beatriz Calmettes; Philippe Gaspar; Jean-Yves Georges; Graeme C. Hays

    2010-01-01

    Understanding food web functioning through the study of natural bio-indicators may constitute a valuable and original approach. In the context of jellyfish proliferation in many overexploited marine ecosystems studying the spatio-temporal foraging patterns of the giant “jellyvore” leatherback turtle turns out to be particularly relevant. Here we analyzed long-term tracking data to assess spatio-temporal foraging patterns in 21 leatherback turtles

  3. Detection of Calendar-Based Periodicities of Interval-Based Temporal Patterns

    E-print Network

    Mahanta, Anjana K

    2012-01-01

    We present a novel technique to identify calendar-based (annual, monthly and daily) periodicities of an interval-based temporal pattern. An interval-based temporal pattern is a pattern that occurs across a time-interval, then disappears for some time, again recurs across another time-interval and so on and so forth. Given the sequence of time-intervals in which an interval-based temporal pattern has occurred, we propose a method for identifying the extent to which the pattern is periodic with respect to a calendar cycle. In comparison to previous work, our method is asymptotically faster. We also show an interesting relationship between periodicities across different levels of any hierarchical timestamp (year/month/day, hour/minute/second etc.).

  4. Pattern recognition of Landsat data based upon temporal trend analysis

    NASA Technical Reports Server (NTRS)

    Engvall, J. L.; Tubbs, J. D.; Holmes, Q. A.

    1977-01-01

    The Delta Classifier defined as an agricultural crop classification scheme employing a temporal trend procedure is applied to more than 100 different Landsat data sets collected during the 1974-1975 growing season throughout the major wheat-producing regions of the United States. The classification approach stresses examination of temporal trends of the Landsat mean vectors of crops in the absence of corresponding ground truth information. It is shown that the resulting classifications compare favorably to ground truth estimates for wheat proportion in those cases where ground truth is available, and that the temporal trend procedure yields estimates of the wheat proportion that are comparable to the best results from maximum likelihood classification with photointerpreter-defined training fields.

  5. Theoretical calculation of the acoustic force on a patterned silicon wafer during megasonic cleaning

    E-print Network

    Deymier, Pierre

    Theoretical calculation of the acoustic force on a patterned silicon wafer during megasonic wafer immersed in water subjected to a megasonic beam. The method of calculation is based on a Green as a function of frequency and the angle the incident megasonic beam makes with the wafer surface

  6. ACOUSTIC IDENTIFICATION AND MEASUREMENT OF ACTIVITY PATTERNS OF WHITE GRUBS IN SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activity patterns of Phyllophaga crinita (Burmeister), P. congrua (LeConte), P. crassissima (Blanchard), and Cyclocephala lurida (Bland) grubs were acoustically monitored in small pots of bluegrass, Poa arachnifera Torr, at varying and constant temperatures over multiple-day periods. Distinctive te...

  7. Acoustics and sociolinguistics: Patterns of communication in hearing impairing classrooms

    NASA Astrophysics Data System (ADS)

    McKellin, William; Shahin, Kimary; Jamieson, Janet; Hodgson, Murray; Pichora-Fuller, Kathleen

    2005-04-01

    In elementary school classes, noise during student led activities is often taken as evidence of successful interaction and learning. In this complex social environment of elementary school classrooms, acquisition of complex language and social skills-the focus of activities in early education-is expected to take place in hearing-hostile environments. Communication and language processing in these contexts requires interactive strategies, discourse forms, and syntactic structures different from the educationally desired forms used in acoustically advantageous environments. Recordings were made of the interaction of groups of students in grades 1-3, 5, and 7 during collaborative group work in their regular classrooms. Each student wore microphones at the ear level and head-mounted video cameras. Each group as a whole was also audio- and videotaped and noise level readings were recorded. Analysis of the acoustical and phonological properties of language heard by each student has demonstrated that the language variety used in these noisy and reverberant settings is similar to that of individuals with hearing impairments. This paper reports similarities between the syntactic structures and pragmatic strategies used by hearing impaired children and normally hearing children in noisy contexts. [Work supported by Peter Wall Institute for Advanced Studies, University of British Columbia.

  8. Acoustic beam steering by light refraction: illustration with directivity patterns of a tilted volume photoacoustic source.

    PubMed

    Raetz, Samuel; Dehoux, Thomas; Perton, Mathieu; Audoin, Bertrand

    2013-12-01

    The symmetry of a thermoelastic source resulting from laser absorption can be broken when the direction of light propagation in an elastic half-space is inclined relatively to the surface. This leads to an asymmetry of the directivity patterns of both compressional and shear acoustic waves. In contrast to classical surface acoustic sources, the tunable volume source allows one to take advantage of the mode conversion at the surface to control the directivity of specific modes. Physical interpretations of the evolution of the directivity patterns with the increasing light angle of incidence and of the relations between the preferential directions of compressional- and shear-wave emission are proposed. In order to compare calculated directivity patterns with measurements of normal displacement amplitudes performed on plates, a procedure is proposed to transform the directivity patterns into pseudo-directivity patterns representative of the experimental conditions. The comparison of the theoretical with measured pseudo-directivity patterns demonstrates the ability to enhance bulk-wave amplitudes and to steer specific bulk acoustic modes by adequately tuning light refraction. PMID:25669249

  9. The Encoding of Temporally Irregular and Regular Visual Patterns in the Human Brain

    PubMed Central

    Zeki, Semir; Hulme, Oliver J.; Roulston, Barrie; Atiyah, Michael

    2008-01-01

    In the work reported here, we set out to study the neural systems that detect predictable temporal patterns and departures from them. We used functional magnetic resonance imaging (fMRI) to locate activity in the brains of subjects when they viewed temporally regular and irregular patterns produced by letters, numbers, colors and luminance. Activity induced by irregular sequences was located within dorsolateral prefrontal cortex, including an area that was responsive to irregular patterns regardless of the type of visual stimuli producing them. Conversely, temporally regular arrangements resulted in activity in the right frontal lobe (medial frontal gyrus), in the left orbito-frontal cortex and in the left pallidum. The results show that there is an abstractive system in the brain for detecting temporal irregularity, regardless of the source producing it. PMID:18478105

  10. RESEARCH Open Access Spatial and temporal distribution patterns of

    E-print Network

    Boyer, Edmond

    larval habitat availability and suitable conditions under which they can thrive. Here, we investigated the impact of environmental factors on the temporal and spatial distribution of larval habitats of Anopheles archival data which provided the complete enumeration of An. arabiensis breeding habitats in three distinct

  11. Gene arrays and temporal patterns of drug response: corticosteroid effects on rat liver

    Microsoft Academic Search

    Richard R. Almon; Debra C. DuBois; Keri E. Pearson; DietrichA Stephan; William J. Jusko

    2003-01-01

    It was hypothesized that expression profiling using gene arrays can be used to distinguish temporal patterns of changes in gene expression in response to a drug in vivo, and that these patterns can be used to identify groups of genes regulated by common mechanisms. A corticosteroid, methylprednisolone (MPL), was administered intravenously to a group of 47 rats ( Rattus rattus)

  12. Temporal consistency in the spatial pattern of seed predation across a forest old field edge

    E-print Network

    field in low predation years. Seed removal rate covaried with spatial pattern of Peromyscus leucopus­581-7141) Received 20 March 2001; accepted in revised form 5 December 2001 Key words: Edge effects, Peromyscus leucopus, Temporal pattern, Tree regeneration Abstract Seed predation is an important factor in determining

  13. Aligning temporal data by sentinel events: discovering patterns in electronic health records

    Microsoft Academic Search

    Taowei David Wang; Catherine Plaisant; Alexander J. Quinn; Roman Stanchak; Shawn Murphy; Ben Shneiderman

    2008-01-01

    Electronic Health Records (EHRs) and other temporal databases contain hidden patterns that reveal important cause-and-effect phenomena. Finding these patterns is a challenge when using traditional query languages and tabular displays. We present an interactive visual tool that complements query formulation by providing operations to align, rank and filter the results, and to visualize estimates of the intervals of validity of

  14. Finding Spatio-Temporal Patterns in Earth Science Data * Pang-Ning Tan+

    E-print Network

    Kumar, Vipin

    and Engineering, Army HPC Research Center University of Minnesota {ptan, steinbac, kumar@cs.umn.edu} ++ NASA Ames-temporal patterns from Earth Science data. The data consists of time series measurements for various Earth science existing ecosystem models (e.g. Net Primary Production). The ecological patterns of interest include

  15. Spatio-temporal patterns of road traffic noise pollution in Karachi, Pakistan

    Microsoft Academic Search

    Mohammed Raza Mehdi; Minho Kim; Jeong Chang Seong; Mudassar Hassan Arsalan

    2011-01-01

    We studied the spatial and temporal patterns of noise exposure due to road traffic in Karachi City, Pakistan, and found that levels of noise were generally higher during mornings and evenings because of the commuting pattern of Karachi residents. This study found the average value of noise levels to be over 66dB, which could cause serious annoyance according to the

  16. Guest Editorial -Journal of Biogeography (2011) in press Running header: Predicting spatio-temporal patterns of species assemblages

    E-print Network

    Alvarez, Nadir

    2011-01-01

    -temporal patterns of species assemblages SESAM ­ a new framework integrating macroecological and species distribution models for predicting spatio-temporal patterns of species assemblages Antoine Guisan1* & Carsten@bio.ku.dk ABSTRACT Two different approaches currently prevail for predicting spatial patterns of species assemblages

  17. Regulation and Temporal Expression Patterns of Vibrio cholerae Virulence Genes during Infection

    Microsoft Academic Search

    Sang Ho Lee; David L Hava; Matthew K Waldor; Andrew Camilli

    1999-01-01

    The temporal expression patterns of the critical Vibrio cholerae virulence genes, tcpA and ctxA, were determined during infection using a recombinase reporter. TcpA was induced biphasically in two temporally and spatially separable events in the small intestine, whereas ctxA was induced monophasically only after, and remarkably, dependent upon, tcpA expression; however, this dependence was not observed during in vitro growth.

  18. Avian Incubation Patterns Reflect Temporal Changes in Developing Clutches.

    PubMed

    Cooper, Caren B; Voss, Margaret A

    2013-01-01

    Incubation conditions for eggs influence offspring quality and reproductive success. One way in which parents regulate brooding conditions is by balancing the thermal requirements of embryos with time spent away from the nest for self-maintenance. Age related changes in embryo thermal tolerance would thus be expected to shape parental incubation behavior. We use data from unmanipulated Black-capped Chickadee (Poecile atricapillus) nests to examine the temporal dynamics of incubation, testing the prediction that increased heat flux from eggs as embryos age influences female incubation behavior and/or physiology to minimize temperature fluctuations. We found that the rate of heat loss from eggs increased with embryo age. Females responded to increased egg cooling rates by altering incubation rhythms (more frequent, shorter on- and off- bouts), but not brood patch temperature. Consequently, as embryos aged, females were able to increase mean egg temperature and decrease variation in temperature. Our findings highlight the need to view full incubation as more than a static rhythm; rather, it is a temporally dynamic and finely adjustable parental behavior. Furthermore, from a methodological perspective, intra- and inter-specific comparisons of incubation rhythms and average egg temperatures should control for the stage of incubation. PMID:23840339

  19. Avian Incubation Patterns Reflect Temporal Changes in Developing Clutches

    PubMed Central

    2013-01-01

    Incubation conditions for eggs influence offspring quality and reproductive success. One way in which parents regulate brooding conditions is by balancing the thermal requirements of embryos with time spent away from the nest for self-maintenance. Age related changes in embryo thermal tolerance would thus be expected to shape parental incubation behavior. We use data from unmanipulated Black-capped Chickadee (Poecile atricapillus) nests to examine the temporal dynamics of incubation, testing the prediction that increased heat flux from eggs as embryos age influences female incubation behavior and/or physiology to minimize temperature fluctuations. We found that the rate of heat loss from eggs increased with embryo age. Females responded to increased egg cooling rates by altering incubation rhythms (more frequent, shorter on- and off- bouts), but not brood patch temperature. Consequently, as embryos aged, females were able to increase mean egg temperature and decrease variation in temperature. Our findings highlight the need to view full incubation as more than a static rhythm; rather, it is a temporally dynamic and finely adjustable parental behavior. Furthermore, from a methodological perspective, intra- and inter-specific comparisons of incubation rhythms and average egg temperatures should control for the stage of incubation. PMID:23840339

  20. An odor stimulator controlling odor temporal pattern applicable in insect olfaction study.

    PubMed

    Okada, Koutaroh; Sakuma, Masayuki

    2009-06-01

    The olfactory system of an insect brain codes for information about odorant quality and quantity using the temporal pattern of neural activity as well as neurons' firing. Although an accurate odor temporal pattern is indispensable for investigations of olfactory systems, it is difficult to control in conventional odor stimulators. To overcome this problem, we fabricated an odor stimulator that can control the odor temporal pattern. The stimulator has 3 major parts: an "odor conditioner," with odor-laden air prepared with known concentrations of odorants; a Pitot tube; and a small wind tunnel of laminar flow. Using this stimulator, we realized not only timing control of the odor stimulation with millisecond order but also constant odor concentrations or intensity of stimulation, with error of 2.4% in replicated trials. PMID:19363088

  1. A Temporal Pattern Search Algorithm for Personal History Event Visualization

    E-print Network

    Shneiderman, Ben

    , sorted by time stamps. Instead, TPS operates on a set of arrays, where each array contains all events of the same type, sorted by time stamps. TPS searches for a particular item in the pattern using a binary a query for the purpose of exploratory analysis, the multiple turnarounds are detri- mental to the process

  2. Spatio-Temporal Motion Pattern Modeling of Extremely Crowded Scenes

    E-print Network

    Paris-Sud XI, Université de

    manuscript, published in "The 1st International Workshop on Machine Learning for Vision-based Motion Analysis Department of Computer Science, Drexel University {lak24, kon}@drexel.edu Abstract. The abundance of video for modeling the motion pattern behavior of extremely crowded scenes. We construct a rich yet compact

  3. Temporal pattern of pulse wave velocity during brachial hyperemia reactivity

    NASA Astrophysics Data System (ADS)

    Graf, S.; Valero, M. J.; Craiem, D.; Torrado, J.; Farro, I.; Zócalo, Y.; Valls, G.; Bía, D.; Armentano, R. L.

    2011-09-01

    Endothelial function can be assessed non-invasively with ultrasound, analyzing the change of brachial diameter in response to transient forearm ischemia. We propose a new technique based in the same principle, but analyzing a continuous recording of carotid-radial pulse wave velocity (PWV) instead of diameter. PWV was measured on 10 healthy subjects of 22±2 years before and after 5 minutes forearm occlusion. After 59 ± 31 seconds of cuff release PWV decreased 21 ± 9% compared to baseline, reestablishing the same after 533 ± 65 seconds. There were no significant changes observed in blood pressure. When repeating the study one hour later in 5 subjects, we obtained a coefficient of repeatability of 4.8%. In conclusion, through analysis of beat to beat carotid-radial PWV it was possible to characterize the temporal profiles and analyze the acute changes in response to a reactive hyperemia. The results show that the technique has a high sensitivity and repeatability.

  4. Detecting spatial and temporal patterns of aboveground production in a tallgrass prairie using remotely sensed data

    SciTech Connect

    Su, Haiping; Krummel, J.R. [Argonne National Lab., IL (United States); Briggs, J.M.; Knapp, A.K.; Blair, J.M. [Kansas State Univ., Manhattan, KS (United States). Div. of Biology

    1996-05-01

    Spatial and temporal patterns of aboveground production is a tallgrass prairie ecosystem constitute one of the important spatial components associated with ecological processes and biophysical resources (e.g. water and nutrients). This study addresses the effects of disturbance, topography, and climate on the spatial and temporal patterns of North American tallgrass prairie at a landscape level by using high resolution satellite data. Spatial heterogeneity derived from the satellite data was related to the impacts of the disturbance of fire and grazing, topographical gradient, and amount of precipitation during the growing season. The result suggests that ecological processes and biophysical resources can be quantified with high resolution satellite data for tallgrass prairie management.

  5. Spatial hearing benefits demonstrated with presentation of acoustic temporal fine structure cues in bilateral cochlear implant listeners.

    PubMed

    Churchill, Tyler H; Kan, Alan; Goupell, Matthew J; Litovsky, Ruth Y

    2014-09-01

    Most contemporary cochlear implant (CI) processing strategies discard acoustic temporal fine structure (TFS) information, and this may contribute to the observed deficits in bilateral CI listeners' ability to localize sounds when compared to normal hearing listeners. Additionally, for best speech envelope representation, most contemporary speech processing strategies use high-rate carriers (?900?Hz) that exceed the limit for interaural pulse timing to provide useful binaural information. Many bilateral CI listeners are sensitive to interaural time differences (ITDs) in low-rate (<300?Hz) constant-amplitude pulse trains. This study explored the trade-off between superior speech temporal envelope representation with high-rate carriers and binaural pulse timing sensitivity with low-rate carriers. The effects of carrier pulse rate and pulse timing on ITD discrimination, ITD lateralization, and speech recognition in quiet were examined in eight bilateral CI listeners. Stimuli consisted of speech tokens processed at different electrical stimulation rates, and pulse timings that either preserved or did not preserve acoustic TFS cues. Results showed that CI listeners were able to use low-rate pulse timing cues derived from acoustic TFS when presented redundantly on multiple electrodes for ITD discrimination and lateralization of speech stimuli. PMID:25190398

  6. Predictability of spatio-temporal patterns in a lattice of coupled FitzHugh–Nagumo oscillators

    PubMed Central

    Grace, Miriam; Hütt, Marc-Thorsten

    2013-01-01

    In many biological systems, variability of the components can be expected to outrank statistical fluctuations in the shaping of self-organized patterns. In pioneering work in the late 1990s, it was hypothesized that a drift of cellular parameters (along a ‘developmental path’), together with differences in cell properties (‘desynchronization’ of cells on the developmental path) can establish self-organized spatio-temporal patterns (in their example, spiral waves of cAMP in a colony of Dictyostelium discoideum cells) starting from a homogeneous state. Here, we embed a generic model of an excitable medium, a lattice of diffusively coupled FitzHugh–Nagumo oscillators, into a developmental-path framework. In this minimal model of spiral wave generation, we can now study the predictability of spatio-temporal patterns from cell properties as a function of desynchronization (or ‘spread’) of cells along the developmental path and the drift speed of cell properties on the path. As a function of drift speed and desynchronization, we observe systematically different routes towards fully established patterns, as well as strikingly different correlations between cell properties and pattern features. We show that the predictability of spatio-temporal patterns from cell properties contains important information on the pattern formation process as well as on the underlying dynamical system. PMID:23349439

  7. The effects of morphine on fixed-interval patterning and temporal discrimination.

    PubMed Central

    Odum, A L; Schaal, D W

    2000-01-01

    Changes produced by drugs in response patterns under fixed-interval schedules of reinforcement have been interpreted to result from changes in temporal discrimination. To examine this possibility, this experiment determined the effects of morphine on the response patterning of 4 pigeons during a fixed-interval 1-min schedule of food delivery with interpolated temporal discrimination trials. Twenty of the 50 total intervals were interrupted by choice trials. Pecks to one key color produced food if the interval was interrupted after a short time (after 2 or 4.64 s). Pecks to another key color produced food if the interval was interrupted after a long time (after 24.99 or 58 s). Morphine (1.0 to 10.0 mg/kg) decreased the index of curvature (a measure of response patterning) during fixed intervals and accuracy during temporal discrimination trials. Accuracy was equally disrupted following short and long sample durations. Although morphine disrupted temporal discrimination in the context of a fixed-interval schedule, these effects are inconsistent with interpretations of the disruption of response patterning as a selective overestimation of elapsed time. The effects of morphine may be related to the effects of more conventional external stimuli on response patterning. PMID:11029024

  8. Acoustic temporal modulation detection in normal-hearing and cochlear implanted listeners: effects of hearing mechanism and development.

    PubMed

    Park, Min-Hyun; Won, Jong Ho; Horn, David L; Rubinstein, Jay T

    2015-06-01

    Temporal modulation detection ability matures over many years after birth and may be particularly sensitive to experience during this period. Profound hearing loss during early childhood might result in greater perceptual deficits than a similar loss beginning in adulthood. We tested this idea by measuring performance in temporal modulation detection in profoundly deaf children and adults fitted with cochlear implants (CIs). At least two independent variables could constrain temporal modulation detection performance in children with CIs: altered encoding of modulation information due to the CI-auditory nerve interface, and atypical development of central processing of sound information provided by CIs. The effect of altered encoding was investigated by testing subjects with one of two different hearing mechanisms (normal hearing vs. CI) and the effect of atypical development was studied by testing two different age groups. All subjects were tested for their ability to detect acoustic temporal modulations of sound amplitude. A comparison of the slope, or cutoff frequency, of the temporal modulation transfer functions (TMTFs) among the four subject groups revealed that temporal resolution was mainly constrained by hearing mechanism: normal-hearing listeners could detect smaller amplitude modulations at high modulation frequencies than CI users. In contrast, a comparison of the height of the TMTFs revealed a significant interaction between hearing mechanism and age group on overall sensitivity to temporal modulation: sensitivity was significantly poorer in children with CIs, relative to the other three groups. Results suggest that there is an age-specific vulnerability of intensity discrimination or non-sensory factors, which subsequently affects sensitivity to temporal modulation in prelingually deaf children who use CIs. PMID:25790949

  9. Temporal and spatial patterns of suicides in Stockholm's subway stations.

    PubMed

    Uittenbogaard, Adriaan; Ceccato, Vania

    2015-08-01

    This paper investigates the potential temporal and spatial variations of suicides in subway stations in Stockholm, Sweden. The study also assesses whether the variation in suicide rates is related to the station environments by controlling for each station's location and a number of contextual factors using regression models and geographical information systems (GIS). Data on accidents are used as references for the analysis of suicides. Findings show that suicides tend to occur during the day and in the spring. They are concentrated in the main transportation hubs but, interestingly, during off-peak hours. However, the highest rates of suicides per passenger are found in Stockholm's subway stations located in the Southern outskirts. More than half of the variation in suicide rates is associated with stations that have walls between the two sides of the platform but still allow some visibility from passers-by. The surrounding environment and socioeconomic context show little effect on suicide rates, but stations embedded in areas with high drug-related crime rates tend to show higher suicide rates. PMID:25958035

  10. Plant Effects on Spatial and Temporal Patterns of Nitrogen Cycling in Shortgrass Steppe

    Microsoft Academic Search

    Howard E. Epstein; Ingrid C. Burke; Arvin R. Mosier

    1998-01-01

    Because of the water-limited nature and discontinuous plant cover of shortgrass steppe, spatial patterns in ecosystem properties\\u000a are influenced more by the presence or absence of plants than by plant type. However, plant type may influence temporal patterns\\u000a of nutrient cycling between plant and soil. Plants having the carbon-3 (C3) or carbon-4 (C4) photosynthetic pathway differ in phenology as well

  11. Temporal trajectories of phosphorus and pedo-patterns mapped in Water Conservation Area 2, Everglades, Florida, USA

    E-print Network

    Grunwald, Sabine

    Temporal trajectories of phosphorus and pedo-patterns mapped in Water Conservation Area 2-patterns in Water Conservation Area 2, a subtropical wetland in the Everglades, Florida. Our specific objectives

  12. Spatio-temporal diffusion pattern and hotspot detection of dengue in Chachoengsao province, Thailand.

    PubMed

    Jeefoo, Phaisarn; Tripathi, Nitin Kumar; Souris, Marc

    2011-01-01

    In recent years, dengue has become a major international public health concern. In Thailand it is also an important concern as several dengue outbreaks were reported in last decade. This paper presents a GIS approach to analyze the spatial and temporal dynamics of dengue epidemics. The major objective of this study was to examine spatial diffusion patterns and hotspot identification for reported dengue cases. Geospatial diffusion pattern of the 2007 dengue outbreak was investigated. Map of daily cases was generated for the 153 days of the outbreak. Epidemiological data from Chachoengsao province, Thailand (reported dengue cases for the years 1999-2007) was used for this study. To analyze the dynamic space-time pattern of dengue outbreaks, all cases were positioned in space at a village level. After a general statistical analysis (by gender and age group), data was subsequently analyzed for temporal patterns and correlation with climatic data (especially rainfall), spatial patterns and cluster analysis, and spatio-temporal patterns of hotspots during epidemics. The results revealed spatial diffusion patterns during the years 1999-2007 representing spatially clustered patterns with significant differences by village. Villages on the urban fringe reported higher incidences. The space and time of the cases showed outbreak movement and spread patterns that could be related to entomologic and epidemiologic factors. The hotspots showed the spatial trend of dengue diffusion. This study presents useful information related to the dengue outbreak patterns in space and time and may help public health departments to plan strategies to control the spread of disease. The methodology is general for space-time analysis and can be applied for other infectious diseases as well. PMID:21318014

  13. Spatio-Temporal Diffusion Pattern and Hotspot Detection of Dengue in Chachoengsao Province, Thailand

    PubMed Central

    Jeefoo, Phaisarn; Tripathi, Nitin Kumar; Souris, Marc

    2011-01-01

    In recent years, dengue has become a major international public health concern. In Thailand it is also an important concern as several dengue outbreaks were reported in last decade. This paper presents a GIS approach to analyze the spatial and temporal dynamics of dengue epidemics. The major objective of this study was to examine spatial diffusion patterns and hotspot identification for reported dengue cases. Geospatial diffusion pattern of the 2007 dengue outbreak was investigated. Map of daily cases was generated for the 153 days of the outbreak. Epidemiological data from Chachoengsao province, Thailand (reported dengue cases for the years 1999–2007) was used for this study. To analyze the dynamic space-time pattern of dengue outbreaks, all cases were positioned in space at a village level. After a general statistical analysis (by gender and age group), data was subsequently analyzed for temporal patterns and correlation with climatic data (especially rainfall), spatial patterns and cluster analysis, and spatio-temporal patterns of hotspots during epidemics. The results revealed spatial diffusion patterns during the years 1999–2007 representing spatially clustered patterns with significant differences by village. Villages on the urban fringe reported higher incidences. The space and time of the cases showed outbreak movement and spread patterns that could be related to entomologic and epidemiologic factors. The hotspots showed the spatial trend of dengue diffusion. This study presents useful information related to the dengue outbreak patterns in space and time and may help public health departments to plan strategies to control the spread of disease. The methodology is general for space-time analysis and can be applied for other infectious diseases as well. PMID:21318014

  14. Temporal patterns of tick-borne granulocytic anaplasmosis in California.

    PubMed

    Rejmanek, Daniel; Nieto, Nathan C; Barash, Nell; Foley, Janet E

    2011-06-01

    Granulocytic anaplasmosis (GA) is a tick-borne emerging infectious disease caused by the bacterium Anaplasma phagocytophilum. From fall 2005 to spring 2007, A. phagocytophilum infection prevalence in small mammals and tick abundance were monitored at 4 study sites in coastal California. The abundance of different life stages of questing Ixodes pacificus ticks fluctuated seasonally with the number of adults peaking December to February, nymphs peaking May to July, and larvae peaking April to June. Numerous Ixodes tick species were found attached to dusky-footed woodrats (Neotoma fuscipes), chimunks (Tamias spp.), and deer mice (Peromyscus maniculatus); however, attached tick larvae on all 3 rodent species were primarily I. pacificus, attached nymphs were primarily I. angustus, and adults were either I. ochotonae, I. spinipalpis, or I. woodi. A. phagocytophilum DNA was detected by PCR in 2.2% (n=275, 95% C.I.=0.09-4.9) of sampled ticks. The overall A. phagocytophilum seroprevalence among small mammals was 7.4% (n=654, 95% C.I.=5.5-9.7) while 7.2% (n=125, 95% C.I.=3.5-13.4) of the animals were found to be PCR-positive. Seropositive animals included woodrats, chipmunks, and deer mice, although only woodrats and chipmunks had PCR-detectable infections. Seroprevalence varied temporally among species with the majority of exposed deer mice detected in fall 2006 and the majority of exposed woodrats and chipmunks identified in spring 2007. This study highlights the importance of multiple-year monitoring of both vectors and wildlife hosts in order to better understand the complex ecology of A. phagocytophilum and other related tick-borne disease agents. PMID:21771541

  15. Experimental quiescent drifting dusty plasmas and temporal dust acoustic wave growth

    SciTech Connect

    Heinrich, J. R.; Kim, S.-H.; Meyer, J. K.; Merlino, R. L. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

    2011-11-15

    We report on dust acoustic wave growth rate measurements taken in a dc (anode glow) discharge plasma device. By introducing a mesh with a variable bias 12-17 cm from the anode, we developed a technique to produce a drifting dusty plasma. A secondary dust cloud, free of dust acoustic waves, was trapped adjacent to the anode side of the mesh. When the mesh was returned to its floating potential, the secondary cloud was released and streamed towards the anode and primary dust cloud, spontaneously exciting dust acoustic waves. The amplitude growth of the excited dust acoustic waves was measured directly along with the wavelength and Doppler shifted frequency. These measurements were compared to fluid and kinetic dust acoustic wave theories. As the wave growth saturated a transition from linear to nonlinear waves was observed. The merging of the secondary and primary dust clouds was also observed.

  16. Spatio-temporal patterns in obsidian consumption in the Southern Nasca Region, Peru

    E-print Network

    Spatio-temporal patterns in obsidian consumption in the Southern Nasca Region, Peru Jelmer W Accepted 10 November 2009 Keywords: Obsidian Exchange Mobility Provenance analysis Nasca Peru a b s t r a c t Geochemical data from 426 obsidian artifacts collected from a range of sites in the Southern Nasca Region (SNR

  17. Temporal Patterns of Crashes of 16-to 17YearOld Drivers in Fairfax County, Virginia

    Microsoft Academic Search

    Laurie A. Hellinga; Anne T. McCartt; Srinivas Mandavilli

    2007-01-01

    Objective. To develop a better understanding of the frequency and characteristics of teenage driver crashes occurring during school commute times.Method. Data were obtained from police reports of crashes involving drivers ages 16–17 that occurred between September 2001 and August 2004 in Fairfax County, Virginia. Temporal patterns and other characteristics of crash involvement during the school year were examined, and crashes

  18. Fourier Harmonic Approach for Visualizing Temporal Patterns of Gene Expression Data

    E-print Network

    Buffalo, State University of New York

    -specialized end-users. The first Fourier harmonic projection (FFHP) was in- troduced to translate the multiFourier Harmonic Approach for Visualizing Temporal Patterns of Gene Expression Data Li Zhang and Aidong Zhang Department of Computer Science and Engineering State University of New York at Buffalo

  19. Spatial and temporal patterns of arsenic concentration in the High Plains Aquifer of Texas, USA

    Microsoft Academic Search

    Paul F. Hudak

    2006-01-01

    Spatial and temporal patterns of dissolved arsenic in groundwater were documented from samples collected at 987 water wells in the High Plains (Ogallala) Aquifer of Texas, USA. Sampled wells had a median depth of 73 m. Historic pesticide and defoliant applications to cotton fields are potential sources of arsenic in the study area. From a survey of samples collected between

  20. Stomach temperature telemetry reveals temporal patterns of foraging success in a free-ranging marine mammal

    Microsoft Academic Search

    DEBORAH AUSTIN; W. D. BOWEN; J. I. MCMILLAN; D. J. BONESS

    2006-01-01

    Summary 1. We studied feeding frequency in free-ranging grey seals using stomach temperature telemetry to test if previously reported sex differences in the diving, movement and diet were reflected in the temporal pattern of foraging success. 2. Data were retrieved from 21 of 32 grey seals from 1999 to 2001, totalling 343 days and 555 feeding events, with individual record

  1. TEMPORAL AND SPATIAL PATTERNS OF METHANE EMISSIONS FROM A RESERVOIR DRAINING AN AGRICULTURAL WATERSHED (abstract)

    EPA Science Inventory

    We used multiple approaches to characterize temporal and spatial patterns in methane (CH4) emissions from a mid-latitude reservoir (William H. Harsha Lake, Ohio, USA) draining an agricultural watershed. Weekly to monthly monitoring at six sites in the reservoir during a 13 month...

  2. TEMPORAL AND SPATIAL PATTERNS OF METHANE EMISSIONS FROM A RESERVOIR DRAINING AN AGRICULTURAL WATERSHED

    EPA Science Inventory

    We used multiple approaches to characterize temporal and spatial patterns in methane (CH4) emissions from a mid-latitude reservoir (William H. Harsha Lake, Ohio, USA) draining an agricultural watershed. Weekly to monthly monitoring at six sites in the reservoir during a 13 month...

  3. TEMPORALLY STABLE PATTERNS IN GRAIN YIELD AND SOIL WATER ON A DRYLAND CATENA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain yields from dryland cropping systems can be affected by water availability, topographic position, and crop rotation. The temporal stability over multiple years of observed spatial patterns on a dryland catena is investigated. Questions remain about: 1) relationships between yield, soil water...

  4. Temporal patterns of mosquito landing on human hosts: implications for detection, monitoring, and vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temporal patterns of landing activity on a human host by female Anopheles quadrimaculatus, Culex nigripalpus, Cx. quinquefasciatus, Ochlerotatus triseriatus and Aedes albopictus varied significantly throughout the diel period and with respect to time of collection within a 15 minute observation peri...

  5. A GIS-based Bayesian approach for analyzing spatial-temporal patterns of traffic crashes

    E-print Network

    Li, Linhua

    2009-06-02

    This thesis develops a GIS-based Bayesian approach for area-wide traffic crash analysis. Five years of crash data from Houston, Texas, are analyzed using a geographic information system (GIS), and spatial-temporal patterns of relative crash risk...

  6. TOOLS FOR PRESENTING SPATIAL AND TEMPORAL PATTERNS OF ENVIRONMENTAL MONITORING DATA

    EPA Science Inventory

    The EPA Health Effects Research Laboratory has developed this data presentation tool for use with a variety of types of data which may contain spatial and temporal patterns of interest. he technology links mainframe computing power to the new generation of "desktop publishing" ha...

  7. Temporal comparison of Broad-Complex expression during eggshell-appendage patterning and morphogenesis in two

    E-print Network

    Borenstein, Elhanan

    Temporal comparison of Broad-Complex expression during eggshell-appendage patterning and morphogenesis in two Drosophila species with different eggshell-appendage numbers Karen E. James, Celeste A in eggshell-appendage number--from as few as one to as many as nine, depending on the species. Appendage

  8. 113 Years of Physical Review: Using Flow Maps to Show Temporal and Topical Citation Patterns

    E-print Network

    Indiana University

    113 Years of Physical Review: Using Flow Maps to Show Temporal and Topical Citation Patterns Bruce time-topic reference system. The citations from 2005 papers are overlaid as flow maps from each topic---network analysis, domain visualization, physical review 1. Introduction This is the very first map of a 113-year

  9. Dynamic Graph-based Relational Learning of Temporal Patterns in Biological Networks Changing over Time

    E-print Network

    Cook, Diane J.

    novel knowledge in data rep- resented as a graph. Several graph-based data mining ap- proaches have beenDynamic Graph-based Relational Learning of Temporal Patterns in Biological Networks Changing over}@eecs.wsu.edu ABSTRACT We propose a dynamic graph-based relational learning ap- proach using graph-rewriting rules

  10. Spatial and temporal patterns of solar radiation based on topography and air temperature

    Microsoft Academic Search

    Sinkyu Kang; Sungwoo Kim; Dowon Lee

    2002-01-01

    Abstract: Incident solar radiation is a driving force for many ecological and hydrological processes. For this study, we developed TopoRad, a new radiation model, to describe spatial and temporal patterns of daily radiation based on topog- raphy and daily temperature regimes. The model was applied to the Mount Jumbong Forest, located in the mid-eastern area of the Korean peninsula; and

  11. ORIGINAL PAPER Temporal changes in the spatial pattern of leaf traits

    E-print Network

    Paris-Sud XI, Université de

    ORIGINAL PAPER Temporal changes in the spatial pattern of leaf traits in a Quercus robur population. Several leaf traits may show spatial structure at the same scale as light or soil resources. However the years than the non-limiting nutrient. We also hypothesized that single leaf traits [leaf N, leaf P

  12. Variability of spatio-temporal patterns in non-homogeneous rings of spiking neurons

    NASA Astrophysics Data System (ADS)

    Yanchuk, Serhiy; Perlikowski, Przemyslaw; Popovych, Oleksandr V.; Tass, Peter A.

    2011-12-01

    We show that a ring of unidirectionally delay-coupled spiking neurons may possess a multitude of stable spiking patterns and provide a constructive algorithm for generating a desired spiking pattern. More specifically, for a given time-periodic pattern, in which each neuron fires once within the pattern period at a predefined time moment, we provide the coupling delays and/or coupling strengths leading to this particular pattern. The considered homogeneous networks demonstrate a great multistability of various travelling time- and space-periodic waves which can propagate either along the direction of coupling or in opposite direction. Such a multistability significantly enhances the variability of possible spatio-temporal patterns and potentially increases the coding capability of oscillatory neuronal loops. We illustrate our results using FitzHugh-Nagumo neurons interacting via excitatory chemical synapses as well as limit-cycle oscillators.

  13. Effective beam pattern of the Blainville's beaked whale (Mesoplodon densirostris) and implications for passive acoustic monitoring.

    PubMed

    Shaffer, Jessica Ward; Moretti, David; Jarvis, Susan; Tyack, Peter; Johnson, Mark

    2013-03-01

    The presence of beaked whales in mass-strandings coincident with navy maneuvers has prompted the development of methods to detect these cryptic animals. Blainville's beaked whales, Mesoplodon densirostris, produce distinctive echolocation clicks during long foraging dives making passive acoustic detection a possibility. However, performance of passive acoustic monitoring depends upon the source level, beam pattern, and clicking behavior of the whales. In this study, clicks recorded from Digital acoustic Tags (DTags) attached to four M. densirostris were linked to simultaneous recordings from an 82-hydrophone bottom-mounted array to derive the source level and beam pattern of the clicks, as steps towards estimating their detectability. The mean estimated on-axis apparent source level for the four whales was 201 dBrms97. The mean 3?dB beamwidth and directivity index, estimated from sequences of clicks directed towards the far-field hydrophones, were 13° and 23?dB, respectively. While searching for prey, Blainville's beaked whales scan their heads horizontally at a mean rate of 3.6°/s over an angular range of some +/-10°. Thus, while the DI indicates a narrow beam, the area of ensonification over a complete foraging dive is large given the combined effects of body and head movements associated with foraging. PMID:23464046

  14. The precise temporal pattern of pre-hearing spontaneous activity is necessary for tonotopic map refinement

    PubMed Central

    Clause, Amanda; Kim, Gunsoo; Sonntag, Mandy; Weisz, Catherine J. C.; Vetter, Douglas E.; Rübsamen, Rudolf; Kandler, Karl

    2014-01-01

    SUMMARY Patterned spontaneous activity is a hallmark of developing sensory systems. In the auditory system, rhythmic bursts of spontaneous activity are generated in cochlear hair cells and propagated along central auditory pathways. The role of these activity patterns in the development of central auditory circuits has remained speculative. Here we demonstrate that blocking efferent cholinergic neurotransmission to developing hair cells in mice that lack the ?9 subunit of nicotinic acetylcholine receptors (?9 KO mice) altered the temporal fine-structure of spontaneous activity without changing activity levels. KO mice showed a severe impairment in the functional and structural sharpening of an inhibitory tonotopic map, as evidenced by deficits in synaptic strengthening and silencing of connections and an absence in axonal pruning. These results provide evidence that the precise temporal pattern of spontaneous activity before hearing onset is crucial for the establishment of precise tonotopy, the major organizing principle of central auditory pathways. PMID:24853941

  15. Spatial and temporal patterns of air pollutants in rural and urban areas of India.

    PubMed

    Sharma, Disha; Kulshrestha, U C

    2014-12-01

    In this study, we analysed spatial and temporal patterns of Suspended Particulate Matter (SPM) concentrations across India. We have also assessed MODIS-derived aerosol optical depth (AOD) variations to characterize the air quality and relate it to SPM, NO2 and SO2 in different areas. In addition, the pollutant concentrations have been mapped using geospatial techniques. The results indicated significant differences in air pollutant levels across rural and urban areas. In general, districts of central and northern India had relatively higher SPM concentrations compared to southern India. Out of the top ten SPM polluted districts in India, nine were located in the state of Uttar Pradesh (UP). We observed significant correlations between the SPM and AOD at different sites. Although spatial and temporal patterns of NO2 and SO2 matched AOD patterns, the correlation strength (r2) varied based on location. The causes and implications of these findings are presented. PMID:25244965

  16. Temporal Feeding Pattern May Influence Reproduction Efficiency, the Example of Breeding Mares

    PubMed Central

    Benhajali, Haifa; Ezzaouia, Mohammed; Lunel, Christophe; Charfi, Faouzia; Hausberger, Martine

    2013-01-01

    Discomfort in farm animals may be induced by inappropriate types or timing of food supplies. Thus, time restriction of meals and lack of roughage have been shown to be one source of emergence of oral stereotypies and abnormal behaviour in horses which have evolved to eat high-fibre diets in small amounts over long periods of time. This feeding pattern is often altered in domestic environment where horses are often fed low fibre meals that can be rapidly consumed. This study aimed at determining the effect of the temporal pattern of feeding on reproductive efficiency of breeding mares, One hundred Arab breeding mares were divided into two groups that differed only in the temporal pattern of roughage availability: only at night for the standard feeding pattern group (SFP mares), night and day for the “continuous feeding” group (CF mares). The total amount of roughage provided was the same as the CF mares received half of the hay during the day while in paddock (haynets). Mares were tested for oestrus detection by teasing with one stallion and were then examined clinically by rectal palpations and ultrasound before being mated naturally or inseminated by fresh or frozen semen. Multivariate logistic regression was used to analyse data. The treatment affected significantly the reproductive efficiency of the mares with fewer oestrus abnormalities (p?=?0.0002) and more fertility (p?=?0.024) in CF mares (conception rate?=?81% versus 55% in SFP mares). Ensuring semi-continous feeding by providing roughage may be a way of fulfilling the basic physiological needs of the horses' digestive system, reducing stress and associated inhibitors of reproduction. To our knowledge, this study provides the first evidence of an impact of temporal feeding patterns on reproductive success in a Mammal. Temporal patterns of feeding may be a major and underestimated factor in breeding. PMID:24098636

  17. Temporal feeding pattern may influence reproduction efficiency, the example of breeding mares.

    PubMed

    Benhajali, Haifa; Ezzaouia, Mohammed; Lunel, Christophe; Charfi, Faouzia; Hausberger, Martine

    2013-01-01

    Discomfort in farm animals may be induced by inappropriate types or timing of food supplies. Thus, time restriction of meals and lack of roughage have been shown to be one source of emergence of oral stereotypies and abnormal behaviour in horses which have evolved to eat high-fibre diets in small amounts over long periods of time. This feeding pattern is often altered in domestic environment where horses are often fed low fibre meals that can be rapidly consumed. This study aimed at determining the effect of the temporal pattern of feeding on reproductive efficiency of breeding mares, One hundred Arab breeding mares were divided into two groups that differed only in the temporal pattern of roughage availability: only at night for the standard feeding pattern group (SFP mares), night and day for the "continuous feeding" group (CF mares). The total amount of roughage provided was the same as the CF mares received half of the hay during the day while in paddock (haynets). Mares were tested for oestrus detection by teasing with one stallion and were then examined clinically by rectal palpations and ultrasound before being mated naturally or inseminated by fresh or frozen semen. Multivariate logistic regression was used to analyse data. The treatment affected significantly the reproductive efficiency of the mares with fewer oestrus abnormalities (p?=?0.0002) and more fertility (p?=?0.024) in CF mares (conception rate?=?81% versus 55% in SFP mares). Ensuring semi-continous feeding by providing roughage may be a way of fulfilling the basic physiological needs of the horses' digestive system, reducing stress and associated inhibitors of reproduction. To our knowledge, this study provides the first evidence of an impact of temporal feeding patterns on reproductive success in a Mammal. Temporal patterns of feeding may be a major and underestimated factor in breeding. PMID:24098636

  18. Characterizing spatial and temporal patterns of intermittent rivers

    NASA Astrophysics Data System (ADS)

    de Vries, Stefan B.; Hoeve, Jasper; Sauquet, Eric; Leigh, Catherine; Bonada, Núria; Fike, Kimberly; Dahm, Clifford; Booij, Martijn J.; Datry, Thibault

    2015-04-01

    Intermittent rivers (IRs) support high biodiversity due to their dynamic alternations between terrestrial and aquatic phases. They represent a large proportion of the river network. However the current knowledge on these ecosystems is limited. The international research project "Intermittent River Biodiversity Analysis and Synthesis" (IRBAS, www.irbas.fr) aims to collect and analyze data on IR biodiversity from France, Spain, North America and Australia. These activities ultimately should help in identifying relationships between flow regime components and ecological responses. The IRBAS project will provide guidelines for policy-makers and resource managers for effective water and habitat management, restoration and preservation. This work examines one of the aspects in the IRBAS project: studying the large-scale spatial distribution of IRs as well as the year-to-year variability of zero-flow events. IRs were described by two variables: the frequency of periods without flow (FREQ) per time period (months or years) and the total number of zero-flow days (DUR) in a specified time window (month or year). Daily discharge data from more than 1700 gauging stations with no significant human influence on flow were collected from France, Spain, Australia and conterminous United States. A minimum length of 30 years of data starting from 1970 was required with less than 5% of missing data. Climate data for France and Australia were also collected. A classification of perennial versus intermittent rivers was defined, with 455 stations out of the 1684 considered "intermittent", i.e. the gauging station records had, on average, at least 5 zero-flow days per year. The analysis of the subset of IRs showed that: - Greater than 50% of the IRs in the database is located in Australia, where only 35% of the stations are considered perennial. In Spain the proportion of IRs reaches 25%. The proportion of intermittent rivers in France (7%) is certainly underestimated as a consequence of the monitoring strategy, i.e. gauging stations have been primarily installed to measure perennial flows of medium size basins and most of the IRs remain ungauged. This is also true in the US where ~ 7% of the current and historical gage network is on intermittent rivers. - Intermittence of rivers demonstrates high seasonality which varies from one country to another. - Links between climate variability and intermittence are not straightforward. No relation was found between annual DUR and annual precipitation in France whereas DUR was significantly correlated with precipitation in Australia. Potential evapotranspiration was correlated with DUR for France, but not for Australia, where the results were more obscure. - No spatially coherent trends in flow intermittence were identified in Spain, France or the USA. Significant trends according to the Mann Kendall test were found in Australia and results suggest trends in yearly DUR consistent with observed changes in rainfall in Western Australia during the last few decades. The El Nino cycle is one of the possible sources of variability in intermittency patterns.

  19. Comparison of temporal and spectral scattering methods using acoustically large breast models derived from magnetic resonance images.

    PubMed

    Hesford, Andrew J; Tillett, Jason C; Astheimer, Jeffrey P; Waag, Robert C

    2014-08-01

    Accurate and efficient modeling of ultrasound propagation through realistic tissue models is important to many aspects of clinical ultrasound imaging. Simplified problems with known solutions are often used to study and validate numerical methods. Greater confidence in a time-domain k-space method and a frequency-domain fast multipole method is established in this paper by analyzing results for realistic models of the human breast. Models of breast tissue were produced by segmenting magnetic resonance images of ex vivo specimens into seven distinct tissue types. After confirming with histologic analysis by pathologists that the model structures mimicked in vivo breast, the tissue types were mapped to variations in sound speed and acoustic absorption. Calculations of acoustic scattering by the resulting model were performed on massively parallel supercomputer clusters using parallel implementations of the k-space method and the fast multipole method. The efficient use of these resources was confirmed by parallel efficiency and scalability studies using large-scale, realistic tissue models. Comparisons between the temporal and spectral results were performed in representative planes by Fourier transforming the temporal results. An RMS field error less than 3% throughout the model volume confirms the accuracy of the methods for modeling ultrasound propagation through human breast. PMID:25096103

  20. Different Temporal Patterns of Specific and General Autobiographical Memories across the Lifespan in Alzheimer's Disease

    PubMed Central

    Philippi, Nathalie; Rousseau, François; Noblet, Vincent; Botzung, Anne; Després, Olivier; Cretin, Benjamin; Kremer, Stéphane; Blanc, Frédéric; Manning, Liliann

    2015-01-01

    We compared specific (i.e., associated with a unique time and space) and general (i.e., extended or repeated events) autobiographical memories (AbM) in Alzheimer's disease (AD). The comparison aims at investigating the relationship between these two components of AbM across the lifespan and the volume of cerebral regions of interest within the temporal lobe. We hypothesized that the ability to elicit specific memories would correlate with hippocampal volume, whereas evoking general memories would be related to lateral temporal lobe. AbM was assessed using the modified Crovitz test in 18 patients with early AD and 18 matched controls. The proportions of total memories—supposed to reflect the ability to produce general memories—and specific memories retrieved were compared between AD patients and controls. Correlations to MRI volumes of temporal cortex were tested. We found different temporal patterns for specific and general memories in AD patients, with (i) relatively spared general memories, according to a temporal gradient that preserved remote memories, predominantly associated with right lateral temporal cortex volume. (ii) Conversely, the retrieval of specific AbMs was impaired for all life periods and correlated with bilateral hippocampal volumes. Our results highlight a shift from an initially episodic to a semantic nature of AbMs during AD, where the abstracted form of memories remains. PMID:26175549

  1. Three Eurasian teleconnection patterns: spatial structures, temporal variability, and associated winter climate anomalies

    NASA Astrophysics Data System (ADS)

    Liu, Yuyun; Wang, Lin; Zhou, Wen; Chen, Wen

    2014-06-01

    The Eurasian (EU) pattern is a distinct teleconnection pattern observed in boreal winter. Since the EU pattern was first identified, three types have been reported in the literature: the conventional EU pattern; the type 1 EU pattern, or Scandinavian (SCAND) pattern; and the type 2 EU pattern, or East Atlantic/West Russia (EATL/WRUS) pattern. Based on several reanalysis and observational datasets, the three EU patterns are extracted using the rotated empirical orthogonal function method. In order to provide a further distinction and understanding of the three EU patterns, a comprehensive side-by-side comparison is performed among them including their temporal variability, horizontal and vertical structure, related stationary Rossby wave activity, impact on climate, and possible driving factors associated with external forcing. The results reveal that all three EU patterns are characterised by a clear quasi-barotropic wave-train structure, but each has a distinct source and centre of action. Accordingly, their impacts on the precipitation and surface air temperature also differ from one other. Further evidence suggests that the conventional EU pattern is likely driven by anomalous sea surface temperatures (SST) over the North Atlantic, in which process the transient eddies are actively involved. The SCAND pattern is partly maintained by the vorticity source over Western Europe, which arises from the anomalous convergence/divergence over the Mediterranean and is efficiently driven by the tropical and southern Indian Ocean SST via divergent circulation. The EATL/WRUS pattern shows some linkage to the North American snow cover, and the involved process remains unclear and needs further investigation.

  2. Arbitrary two-dimensional multiphoton excitation patterns with temporally focused digital holograms

    NASA Astrophysics Data System (ADS)

    Oron, Dan; Papagiakoumou, Eirini; de-Sars, Vincent; Emiliani, Valentina

    2009-02-01

    Multiphoton excitation has recently found application in the fields of bioimaging, uncaging and lithography. In order to fully exploit the advantages of nonlinear excitation, in particular the axial resolution due to nonlinearity, most systems to date operate with point or multipoint excitation, while scanning either the laser beam or the sample to generate the illumination pattern. Here we combine the recently introduced technique of scanningless multiphoton excitation by temporal focusing with recent advances in digital holography to generate arbitrarily shaped, depth resolved, two-dimensional excitation patterns completely without scanning. This is of particular importance in applications requiring uniform excitation of large areas over short time scales, such as neuronal activation by multiphoton uncaging of neurotransmitters. We present an experimental and theoretical analysis of the effect of spatial patterning on the depth resolution achieved in temporal focusing microscopy. It is shown that the depth resolution for holographic excitation is somewhat worse than that achieved for uniform illumination. This is also accompanied by the appearance of a speckle pattern at the temporal focal plane. The origin of the two effects, as well as means to overcome them, are discussed.

  3. Temporal and Spatial Patterns of Habitat Use by Juveniles of a Small Coastal Shark (Mustelus lenticulatus) in an Estuarine Nursery

    PubMed Central

    Francis, Malcolm P.

    2013-01-01

    Juvenile rig (Mustelus lenticulatus) were internally tagged with acoustic transmitters and tracked with acoustic receivers deployed throughout two arms of Porirua Harbour, a small (7 km2) estuary in New Zealand. Ten rig were tracked for up to four months during summer–autumn to determine their spatial and temporal use of the habitat. The overall goal was to estimate the size of Marine Protected Areas required to protect rig nursery areas from direct human impacts. Rig showed clear site preferences, but those preferences varied among rig and over time. They spent most of their time in large basins and on shallow sand and mud flats around the margins, and avoided deep channels. Habitat range increased during autumn for many of the rig. Only one shark spent time in both harbour arms, indicating that there was little movement between the two. Rig home ranges were 2–7 km2, suggesting that an effective MPA would need to cover the entire Porirua Harbour. They moved to outer harbour sites following some high river flow rates, and most left the harbour permanently during or soon after a river spike, suggesting that they were avoiding low salinity water. Rig showed strong diel movements during summer, although the diel pattern weakened in autumn. Persistent use of the same day and night sites indicates that diel movements are directed rather than random. Further research is required to determine the sizes of rig home ranges in larger harbours where nursery habitat is more extensive. Marine Protected Areas do not control land-based impacts such as accelerated sedimentation and heavy metal pollution, so integration of marine and terrestrial management tools across a range of government agencies is essential to fully protect nursery areas. PMID:23437298

  4. A smart pattern recognition system for the automatic identification of aerospace acoustic sources

    NASA Technical Reports Server (NTRS)

    Cabell, R. H.; Fuller, C. R.

    1989-01-01

    An intelligent air-noise recognition system is described that uses pattern recognition techniques to distinguish noise signatures of five different types of acoustic sources, including jet planes, propeller planes, a helicopter, train, and wind turbine. Information for classification is calculated using the power spectral density and autocorrelation taken from the output of a single microphone. Using this system, as many as 90 percent of test recordings were correctly identified, indicating that the linear discriminant functions developed can be used for aerospace source identification.

  5. Temporal patterns of deer-vehicle collisions consistent with deer activity pattern and density increase but not general accident risk.

    PubMed

    Hothorn, Torsten; Müller, Jörg; Held, Leonhard; Möst, Lisa; Mysterud, Atle

    2015-08-01

    The increasing number of deer-vehicle collisions (DVCs) across Europe during recent decades poses a serious threat to human health and animal welfare and increasing costs for society. DVCs are triggered by both a human-related and a deer-related component. Mitigation requires an understanding of the processes driving temporal and spatial collision patterns. Separating human-related from deer-related processes is important for identifying potentially effective countermeasures, but this has rarely been done. We analysed two time series of 341,655 DVCs involving roe deer and 854,659 non-deer-related accidents (non-DVCs) documented between 2002 and 2011. Nonparametric smoothing and temporal parametric modelling were used to estimate annual, seasonal, weekly and diurnal patterns in DVCs, non-DVCs and adjusted DVCs. As we had access to data on both DVCs and non-DVCs, we were able to disentangle the relative role of human-related and deer-related processes contributing to the overall temporal DVC pattern. We found clear evidence that variation in DVCs was mostly driven by deer-related and not human-related activity on annual, seasonal, weekly and diurnal scales. A very clear crepuscular activity pattern with high activity after sunset and around sunrise throughout the year was identified. Early spring and the mating season between mid-July and mid-August are typically periods of high roe deer activity, and as expected we found a high number of DVC during these periods, although these patterns differed tremendously during different phases of a day. The role of human activity was mainly reflected in fewer DVCs on weekends than on weekdays. Over the ten-year study period, we estimated that DVCs increased by 25%, whereas the number of non-DVCs decreased by 10%. Increasing deer densities are the most likely driver behind this rise in DVCs. Precise estimates of DVC patterns and their relationship to deer and human activity patterns allow implementation of specific mitigation measures, such as tailored driver warning systems or temporary speed limits. To prevent a further increase in DVCs, state-wide measures to decrease roe deer density are required. PMID:25984644

  6. Temporal resolutions of time-reversal and passive-phase conjugation for underwater acoustic communications. I. Stationary source and receivers in a dynamic shallow-water environment

    NASA Astrophysics Data System (ADS)

    Yang, T. C.

    2002-11-01

    Multipath arrivals cause interference between transmitted symbols and hence, symbol errors in underwater acoustic communications. A time-reversal mirror uses the ocean to combine the multipath arrivals and can be used for underwater acoustic communications. Passive-phase conjugation uses the received data of a probe signal to deconvolve the channel transfer function and thereby removes the multipath effects. In this paper, we study the following temporal resolutions of a time-reversal or passive-phase conjugation process as applied to underwater acoustic communications: (1) the time resolution or the pulse width of a backpropagated, time-compressed pulse as compared with the original transmitted pulse; (2) the effectiveness of temporal focusing as measured by the peak-to-sidelobe ratio of the backpropagated or phase-conjugated pulse; both pulse elongation and sidelobe leakages are causes of intersymbol interference and bit errors for communications; (3) the duration of temporal focusing or the temporal coherence time of the underwater acoustic channel; and (4) the stability of temporal focusing as measured by the phase fluctuations of successive pulses (symbols). BPSK signals collected at sea were used to extract the above four parameters. The bit error rates are modeled with simulated data. [Work supported by ONR.

  7. Temporal resolutions of time-reversal and passive-phase conjugation for underwater acoustic communications. II. The effect of source motion

    NASA Astrophysics Data System (ADS)

    Yang, T. C.

    2002-11-01

    Multipath arrivals cause interference between transmitted symbols and hence, symbol errors in underwater acoustic communications. A time-reversal mirror uses the ocean to combine the multipath arrivals and can be used for underwater acoustic communications. Passive-phase conjugation uses the received data of a probe signal to deconvolve the channel transfer function and thereby removes the multipath effects. In this paper, we study the following temporal resolutions of a time-reversal or passive-phase conjugation process as applied to underwater acoustic communications: (1) the time resolution or the pulse width of a backpropagated, time-compressed pulse as compared with the original transmitted pulse; (2) the effectiveness of temporal focusing as measured by the peak-to-sidelobe ratio of the backpropagated or phase conjugated pulse; both pulse elongation and sidelobe leakages are causes of intersymbol interference and bit errors for communications; (3) the duration of temporal focusing or the temporal coherence time of the underwater acoustic channel; and (4) the stability of temporal focusing as measured by the phase fluctuations of successive pulses (symbols). We analyze BPSK signals collected at sea from a moving source, extract the above four parameters, and evaluate the bit error rate. [Work supported by ONR.

  8. Exploratory Analysis of Spatial-Temporal Patterns of Air Pollution in the City

    NASA Astrophysics Data System (ADS)

    Champendal, Alexandre; Kanevski, Mikhail; Huguenot, Pierre-Emmanuel; Golay, Jean

    2013-04-01

    Air pollution in the city is an important problem influencing environment, well-being of society, economy, management of urban zones, etc. The problem is extremely difficult due to a very complex distribution of the pollution sources, morphology of the city and dispersion processes leading to multivariate nature of the phenomena and high local spatial-temporal variability. The task of understanding, modelling and prediction of spatial-temporal patterns of air pollution in urban zones is an interesting and challenging topic having many research axes from science-based modelling to geostatistics and data mining. The present research mainly deals with a comprehensive exploratory analysis of spatial-temporal air pollution data using statistical, geostatistical and machine learning tools. This analysis helps to 1) understand and model spatial-temporal correlations using variography, 2) explore the temporal evolution of spatial correlation matrix; 3) analyse and visualize an interconnection between measurement stations using network science tools; 4) quantify the availability and predictability of structured patterns. The real data case study deals with spatial-temporal air pollution data of canton Geneva (2002-2011). Carbon dioxide (NO2) have caught our attention. It has effects on health: nitrogen dioxide can irritate the lungs, effects on plants; NO2 contributes to the phenomenon of acid rain. The negative effects of nitrogen dioxides on plants are reducing the growth, production and pesticide resistance. And finally the effects on materials: nitrogen dioxides increase the corrosion. Well-defined patterns of spatial-temporal correlations were detected. The analysis and visualization of spatial correlation matrix for 91 stations were carried out using the network science tools and high levels of clustering were revealed. Moving Window Correlation Matrix and Spatio-temporal variography methods were applied to define and explore the dynamic of our data. More than just exploratory of data analysis, this study brings to front the high complexity of air pollution in the city. This approach allowed the definition, parameterisation and analysis of the air pollution data in the city with the future goal of integrating this knowledge in the development of different models of air pollution diffusion. Keywords: space-time environmental data, variography, moving window correlation matrix, network science

  9. Crystallography: Precise Manipulation and Patterning of Protein Crystals for Macromolecular Crystallography Using Surface Acoustic Waves (Small 23/2015).

    PubMed

    Guo, Feng; Zhou, Weijie; Li, Peng; Mao, Zhangming; Yennawar, Neela H; French, Jarrod B; Huang, Tony Jun

    2015-06-01

    J. B. French, T. J. Huang, and co-workers develop a surface acoustic wave method to manipulate protein crystals for macromolecular crystallography. On page 2733, a capillary tube is coupled onto a piezoelectric substrate with a pair of interdigital transducers. When the transducers are turned on, an acoustic field is generated and introduced into the capillary through a thin layer of coupling gel. The micrometersized protein crystals suspended in the capillary will then be manipulated by the acoustic field and aligned into a linear pattern. PMID:26097081

  10. Spatial-temporally resolved high-frequency surface acoustic waves on silicon investigated by femtosecond spectroscopy

    NASA Astrophysics Data System (ADS)

    Schubert, Martin; Grossmann, Martin; Ristow, Oliver; Hettich, Mike; Bruchhausen, Axel; Barretto, Elaine C. S.; Scheer, Elke; Gusev, Vitalyi; Dekorsy, Thomas

    2012-07-01

    Various types of surface acoustic waves are generated by femtosecond pulses on bulk silicon with aluminium stripe transducers. Rayleigh and leaky longitudinal surface acoustic wave modes are detected in the time domain for various propagation distances. The modes are identified by measuring on various pitches and comparing the spectra with finite element calculations. The lifetimes of the modes are determined quantitatively by spatially separating pump and probe beam, showing a significant difference in the lifetimes of both modes. We were able to excite and measure Rayleigh modes with frequencies of up to 90 GHz using a 100 nm period grating.

  11. Spatial and Temporal Patterns in Macrofaunal Diversity Components Relative to Sea Floor Landscape Structure

    PubMed Central

    Zajac, Roman N.; Vozarik, Joseph M.; Gibbons, Brittney R.

    2013-01-01

    We examined temporal changes in macrofaunal ?- and ?-diversity over several spatial scales (within patches, among patches, across landscapes and across regions) in Long Island Sound on the northeast USA coast. Regional ?-diversity was estimated at 144 taxa, however ?-diversity fluctuated over time as did ?- and ?-diversity components. Based on additive partitioning, patch- and region-scale ?-diversity components generally had the highest contributions to ?-diversity; lower percentages were found at within-patch and landscape scales. Multiplicative diversity partitioning indicated highest species turnover at within- and among patch scales. For all partition results, within-patch and patch-scale ?-diversity increased sharply when hypoxia impacted benthic communities. Spatial variation in diversity components can be attributed to the collection of different patch types at varying spatial scales and their associated habitats across the benthic landscapes, as well as gradients in depth and other estuarine-scale characteristics. Temporal variation in diversity components across spatial scales may be related to seasonal changes in habitat heterogeneity, species population dynamics, and seasonal disturbances. Rare species were significant and temporally consistent components of macrofaunal diversity patterns over different spatial scales. Our findings agree with other marine and terrestrial studies that show diversity components vary significantly over different spatial scales and the importance of habitat/landscape heterogeneity in supporting diversity. However, our results indicate that the relative contributions of scale-specific ?-diversity components can also change significantly over time. Thus, studies of diversity patterns across patches and landscapes based on data collected at one time, or assembled into a single data set from different times, may not capture the full suite of diversity patterns that occur over varying spatial scales and any time-specific determinants of those patterns. Many factors that shape and maintain sedimentary communities vary temporally, and appear to play an important role in determining and maintaining macrofaunal diversity over different spatial scales. PMID:23776552

  12. The predatory behavior of wintering Accipiter hawks: temporal patterns in activity of predators and prey

    Microsoft Academic Search

    Timothy C. Roth; Steven L. Lima

    2007-01-01

    Studies focused on how prey trade-off predation and starvation risk are prevalent in behavioral ecology. However, our current\\u000a understanding of these trade-offs is limited in one key respect: we know little about the behavior of predators. In this study,\\u000a we provide some of the first detailed information on temporal patterns in the daily hunting behavior of bird-eating Accipiter hawks and

  13. Dynamics of spatio-temporal patterns in associative networks of spiking neurons

    Microsoft Academic Search

    Thomas Wennekers

    2000-01-01

    This paper studies dynamical properties of spatio-temporal pattern sequences ("synfirechains") in associative networks of spiking neurons. Employing postsynaptic potentialswith a finite rise-time, the replay speed of stored sequences can be controledby unspecific background signals. In addition, the speed also depends on the numberof co-activated sequences, but balanced inhibition can prevent this dependency.An implicit equation is derived and solved numerically which

  14. Spatio-temporal patterns of forest carbon dioxide exchange based on global eddy covariance measurements

    Microsoft Academic Search

    XingChang Wang; ChuanKuan Wang; GuiRui Yu

    2008-01-01

    Spatio-temporal patterns and driving mechanisms of forest carbon dioxide (CO2) exchange are the key issues on terrestrial ecosystem carbon cycles, which are the basis for developing and validating ecosystem\\u000a carbon cycle models, assessing and predicting the role of forests in global carbon balance. Eddy covariance (EC) technique,\\u000a an important method for measuring energy and material exchanges between terrestrial ecosystems and

  15. Contact printing of metallic pattern and its applications on fabricating high-frequency surface acoustic wave (SAW) devices

    Microsoft Academic Search

    Yung-Chun Lee; Chun-Hung Chen; Hsueh-Liang Chen; Chin-Hsin Liu; Cheng-Yu Chiu; Hung-Yi Lin

    2008-01-01

    In this paper, two types of contact-printing methods for micro\\/nano-lithography are developed and their application on fabricating high-frequency surface acoustic wave (SAW) devices are investigated. First of all, a light-assisted metal film patterning (LAMP) method which transfers a patterned metal film directly from a silicon mold to a substrate is discussed. The pattern transformation relies on both mechanical contact pressure

  16. Discrimination of acoustic patterns in rats using the water T-maze

    PubMed Central

    de la Mora, Daniela M.; Toro, Juan M.

    2014-01-01

    The extraction of abstract rules and their generalization to new items has been proposed to be at the heart of higher cognitive functions such as language. Research with animals has shown that various species can extract rather complex patterns from the input, as well as establish abstract same/different relations. However, much of these findings have been observed after extensive training procedures. Here, we tested rats’ capacity to discriminate and generalize tone triplets that entailed a repetition from triplets that followed an ordinal, non-repeating pattern following a relatively short discrimination training procedure in a water T-maze. Our findings demonstrate that, under this procedure and after only 12 sessions, rats can learn to discriminate both patterns when a reliable difference in pitch variations is present across them (Experiment 1). When differences in pitch are eliminated (Experiment 2), no discrimination between patterns is found. Results suggest a procedure based on a water T-maze might be used to explore discrimination of acoustic patterns in rodents. PMID:25729120

  17. Precise Manipulation and Patterning of Protein Crystals for Macromolecular Crystallography Using Surface Acoustic Waves.

    PubMed

    Guo, Feng; Zhou, Weijie; Li, Peng; Mao, Zhangming; Yennawar, Neela H; French, Jarrod B; Huang, Tony Jun

    2015-06-01

    Advances in modern X-ray sources and detector technology have made it possible for crystallographers to collect usable data on crystals of only a few micrometers or less in size. Despite these developments, sample handling techniques have significantly lagged behind and often prevent the full realization of current beamline capabilities. In order to address this shortcoming, a surface acoustic wave-based method for manipulating and patterning crystals is developed. This method, which does not damage the fragile protein crystals, can precisely manipulate and pattern micrometer and submicrometer-sized crystals for data collection and screening. The technique is robust, inexpensive, and easy to implement. This method not only promises to significantly increase efficiency and throughput of both conventional and serial crystallography experiments, but will also make it possible to collect data on samples that were previously intractable. PMID:25641793

  18. Diel behavioral pattern of hatchery-reared black-spot tuskfish determined by acoustic telemetry in the natural environment and video observation in a fish tank

    Microsoft Academic Search

    YUUKI KAWABATA; JUNICHI OKUYAMA; KIMIO ASAMI; KENZO YOSEDA; NOBUAKI ARAI

    Diel behavioral pattern of hatchery-reared black-spot tuskfish was examined by acoustic telemetry in the natural environment and video observation in a fish tank. Nine tuskfish were monitored using acoustic telemetry for 150 days; five fish were observed in a fish tank for 2 days. In the acoustic telemetry tracking, tuskfish moved horizontally and vertically during the day; they stayed still

  19. Temporal and Spatial Variability in the Migration Patterns of Juvenile and Subadult Bull Trout in Northeastern Oregon

    Microsoft Academic Search

    Kristen Homel; Phaedra Budy

    2008-01-01

    Conservation planning for threatened bull trout Salvelinus confluentus requires the identification of temporal and spatial movement patterns to better understand the patch size and connectivity requirements of different behavioral strategies (e.g., resident and migratory) and life stages (e.g., juvenile and adult). Although these patterns have been identified for adults, less is known about the movement patterns of juvenile and subadult

  20. Spatio-temporal patterns of dengue in Malaysia: combining address and sub-district level.

    PubMed

    Ling, Cheong Y; Gruebner, Oliver; Krämer, Alexander; Lakes, Tobia

    2014-11-01

    Spatio-temporal patterns of dengue risk in Malaysia were studied both at the address and the sub-district level in the province of Selangor and the Federal Territory of Kuala Lumpur. We geocoded laboratory-confirmed dengue cases from the years 2008 to 2010 at the address level and further aggregated the cases in proportion to the population at risk at the sub-district level. Kulldorff's spatial scan statistic was applied for the investigation that identified changing spatial patterns of dengue cases at both levels. At the address level, spatio-temporal clusters of dengue cases were concentrated at the central and south-eastern part of the study area in the early part of the years studied. Analyses at the sub-district level revealed a consistent spatial clustering of a high number of cases proportional to the population at risk. Linking both levels assisted in the identification of differences and confirmed the presence of areas at high risk for dengue infection. Our results suggest that the observed dengue cases had both a spatial and a temporal epidemiological component, which needs to be acknowledged and addressed to develop efficient control measures, including spatially explicit vector control. Our findings highlight the importance of detailed geographical analysis of disease cases in heterogeneous environments with a focus on clustered populations at different spatial and temporal scales. We conclude that bringing together information on the spatio-temporal distribution of dengue cases with a deeper insight of linkages between dengue risk, climate factors and land use constitutes an important step towards the development of an effective risk management strategy. PMID:25545931

  1. New model of human luminance pattern vision mechanisms: analysis of the effects of pattern orientation, spatial phase, and temporal frequency

    NASA Astrophysics Data System (ADS)

    Foley, John M.; Boynton, Geoffrey M.

    1994-03-01

    Models of human pattern vision mechanisms are examined in light of new results in psychophysics and single-cell recording. Four experiments on simultaneous masking of Gabor patterns by sinewave gratings are described. In these experiments target contrast thresholds are measured as functions of masker contrast, orientation, spatial phase, and temporal frequency. The results are used to test the theory of simultaneous masking proposed by Legge and Foley that is based on mechanisms that sum excitation linearly over a receptive field and produce a response that is an s-shaped transform of this sum. The theory is shown to be inadequate. Recent single-cell-recording results from simple cells in the cat show that these cells receive a broadband divisive input as well as an input that is summed linearly over their receptive fields. A new theory of simultaneous masking based on mechanisms with similar properties is shown to describe the psychophysical results well. Target threshold vs masker contrast (TvC) functions for a set of target-masker pairs are used to estimate the parameters of the theory including the excitatory and inhibitory sensitivities of the mechanisms along the various pattern dimensions. The human luminance pattern vision mechanisms, unlike most of the cells, do not saturate at high contrast.

  2. Emergence of striation patterns in acoustic signals reflected from dynamic surface waves.

    PubMed

    Choo, Youngmin; Seong, Woojae; Song, Heechun

    2014-09-01

    A striation pattern can emerge in high-frequency acoustic signals interacting with dynamic surface waves. The striation pattern is analyzed using a ray tracing algorithm for both a sinusoidal and a rough surface. With a source or receiver close to the surface, it is found that part of the surface on either side of the specular reflection point can be illuminated by rays, resulting in time-varying later arrivals in channel impulse response that form the striation pattern. In contrast to wave focusing associated with surface wave crests, the striation occurs due to reflection off convex sections around troughs. Simulations with a sinusoidal surface show both an upward (advancing) and downward (retreating) striation patterns that depend on the surface-wave traveling direction and the location of the illuminated area. In addition, the striation length is determined mainly by the depth of the source or receiver, whichever is closer in range to the illuminated region. Even with a rough surface, the striation emerges in both directions. However, broadband (7-13?kHz) simulations in shallow water indicate that the longer striation in one direction is likely pronounced against a quiet noise background, as observed from at-sea experimental data. PMID:25190380

  3. Employing passive acoustics as a temporally precise monologue for constraining ebullitive methane fluxes in warming subarctic lakes

    NASA Astrophysics Data System (ADS)

    Osman, M.; Varner, R. K.; Palace, M. W.; Wik, M.; Crill, P. M.; Lang, A.

    2013-12-01

    Systematic difficulties in capturing the large spatial and temporal variability of ebullition (bubbling) has promoted a broad range of uncertainty in our understanding of the role of lakes as key emitters of atmospheric methane (CH4). With the projected warming and ongoing thawing of high-latitude frozen peatlands abundant in small lakes and ponds, there is an increasing need for methods that provide high-temporal resolution delineating precisely when and under what circumstances ebullitive fluxes occur. Employing the well-established Minnaert resonance formula as a reliable proxy for bubble volume, we designed a system of passive acoustic hydrophone sensors calibrated to continuously record ebullition from lakes at 160 kbits/sec. We present here the results of three summer field seasons (2011-2013) of acoustic and manual bubble flux measurements from four subarctic lakes situated in discontinuous permafrost regions of northern Sweden and Alaska. Results show trends similar to prior lake measurements in the subarctic. We found wide variation in CH4 concentrations, spanning between 0.10 to 95.16%. Fluxes ranged from 0-279.72 mg CH4 m-2 d-1 and averaged 12.03 mg CH4 m-2 d-1 (n = 401) over the three year period. High resolution time series analysis of our measurements will be compared alongside standard meteorological parameters such as atmospheric pressure, temperature, rainfall, water table, wind speed, and radiative inputs to infer dominant external forcings on ebullition. Radiocarbon and 13C/12C ratios of bubble samples collected from Swedish lakes in July 2013 are to be subsequently analyzed for age, transport, and production mechanisms.

  4. Are obsidian subsources meaningful units of analysis?: temporal and spatial patterning of subsources in the Coso Volcanic Field,

    E-print Network

    Are obsidian subsources meaningful units of analysis?: temporal and spatial patterning Archaeologists frequently assign artifacts to chemically discrete subsignatures of major obsidian sources. While reserved. Keywords: Obsidian fingerprinting; Intra-source variability; Coso Volcanic Field; California

  5. TEMPORAL PATTERNS IN THREE-DIMENSIONAL STRUCTURE AND ACTIVITY OF SCHOOLS OF THE ATLANTIC SILVERSIDE 'MENIDIA MENIDIA'

    EPA Science Inventory

    Temporal patterns in the structure and activity of schools of the Atlantic silverside Menidia menidia were investigated under laboratory conditions using a new computerized video technique for three-dimensional analysis. Fish were collected by seining at Middle Bridge, Pettaquans...

  6. Temporal variations of low-order spherical harmonic representations of sunspot group patterns: Evidence for solar spin-orbit coupling

    Microsoft Academic Search

    D. Juckett

    2003-01-01

    The spatial and temporal patterns of sunspot groups spanning 125 years are explored using surface spherical harmonic (SSH) analysis at a temporal resolution of one Carrington Rotation (CR). SSHs spanning order, 1 <= m <= 12, and degree, l, satisfying (l-m) <= 12 are calculated for each CR from 300 to 1950 and are expressed as amplitude and spatial phase

  7. Spatio-temporal patterns of leptospirosis in Thailand: is flooding a risk factor?

    PubMed

    Suwanpakdee, S; Kaewkungwal, J; White, L J; Asensio, N; Ratanakorn, P; Singhasivanon, P; Day, N P J; Pan-Ngum, W

    2015-07-01

    We studied the temporal and spatial patterns of leptospirosis, its association with flooding and animal census data in Thailand. Flood data from 2010 to 2012 were extracted from spatial information taken from satellite images. The incidence rate ratio (IRR) was used to determine the relationship between spatio-temporal flooding patterns and the number of human leptospirosis cases. In addition, the area of flood coverage, duration of waterlogging, time lags between flood events, and a number of potential animal reservoirs were considered in a sub-analysis. There was no significant temporal trend of leptospirosis over the study period. Statistical analysis showed an inconsistent relationship between IRR and flooding across years and regions. Spatially, leptospirosis occurred repeatedly and predominantly in northeastern Thailand. Our findings suggest that flooding is less influential in leptospirosis transmission than previously assumed. High incidence of the disease in the northeastern region is explained by the fact that agriculture and animal farming are important economic activities in this area. The periodic rise and fall of reported leptospirosis cases over time might be explained by seasonal exposure from rice farming activities performed during the rainy season when flood events often occur. We conclude that leptospirosis remains an occupational disease in Thailand. PMID:25778527

  8. Analysis of spatial and temporal water pollution patterns in Lake Dianchi using multivariate statistical methods.

    PubMed

    Yang, Yong-Hui; Zhou, Feng; Guo, Huai-Cheng; Sheng, Hu; Liu, Hui; Dao, Xu; He, Cheng-Jie

    2010-11-01

    Various multivariate statistical methods including cluster analysis (CA), discriminant analysis (DA), factor analysis (FA), and principal component analysis (PCA) were used to explain the spatial and temporal patterns of surface water pollution in Lake Dianchi. The dataset, obtained during the period 2003-2007 from the Kunming Environmental Monitoring Center, consisted of 12 variables surveyed monthly at eight sites. The CA grouped the 12 months into two groups, August-September and the remainder, and divided the lake into two regions based on their different physicochemical properties and pollution levels. The DA showed the best results for data reduction and pattern recognition in both temporal and spatial analysis. It calculated four parameters (TEMP, pH, CODMn, and Chl-a) to 85.4% correct assignment in the temporal analysis and three parameters (BOD, NH?+-N, and TN) to almost 71.7% correct assignment in spatial analysis of the two clusters. The FA/PCA applied to datasets of two special clusters of the lake calculated four factors for each region, capturing 72.5% and 62.5% of the total variance, respectively. Strong loadings included DO, BOD, TN, CODCr, CODMn, NH?+-N, TP, and EC. In addition, box-whisker plots and GIS further facilitated and supported the multivariate analysis results. PMID:19936953

  9. Functional and anatomic correlates of two frequently observed temporal lobe seizure-onset patterns.

    PubMed

    Velasco, A L; Wilson, C L; Babb, T L; Engel, J

    2000-01-01

    Intracranial depth electrode EEG records of 478 seizures, recorded in 68 patients undergoing diagnostic monitoring with depth electrodes, were evaluated to investigate the correlates of electrographic onset patterns in patients with temporal lobe seizures. The seizure onsets in 78% of these patients were identified as either hypersynchronous onsets, beginning with low-frequency, high-amplitude spikes, or low-voltage fast (LVF) onsets, increasing in amplitude as the seizure progressed. The number of patients (35) having hypersynchronous seizure onsets was nearly twice that of patients (18) having LVF onsets. Three major differences were seen among patients with the two seizure-onset patterns. When compared with patients having LVF onsets, patients with hypersynchronous seizure onsets had a significantly greater probability of having (1) focal rather than regional seizure onsets (p < 0.01), (2) seizures spreading more slowly to the contralateral mesial temporal lobe (p < 0.003), and (3) cell counts in resected hippocampal tissue showing greater neuronal loss (p < 0.001). The results provide evidence that the most frequent electrographic abnormality associated with mesial temporal seizures is local hypersynchrony, a condition associated with major neuronal loss in the hippocampus. The results also indicate that LVF seizure onsets more frequently represent widely distributed discharges, which interact with and spread more rapidly to surrounding neocortical areas. PMID:10709214

  10. Modelling spatio-temporal patterns of long-distance Culicoides dispersal into northern Australia.

    PubMed

    Eagles, D; Walker, P J; Zalucki, M P; Durr, P A

    2013-07-01

    Novel arboviruses, including new serotypes of bluetongue virus, are isolated intermittently from cattle and insects in northern Australia. These viruses are thought to be introduced via windborne dispersal of Culicoides from neighbouring land masses to the north. We used the HYSPLIT particle dispersal model to simulate the spatio-temporal patterns of Culicoides dispersal into northern Australia from nine putative source sites across Indonesia, Timor-Leste and Papua New Guinea. Simulated dispersal was found to be possible from each site, with the islands of Timor and Sumba highlighted as the likely principal sources and February the predominant month of dispersal. The results of this study define the likely spatial extent of the source and arrival regions, the relative frequency of dispersal from the putative sources and the temporal nature of seasonal winds from source sites into arrival regions. Importantly, the methodology and results may be applicable to other insect and pathogen incursions into northern Australia. PMID:23642857

  11. Can acoustic emissions patterns signal imminence of avalanche events in a growing sand pile?

    NASA Astrophysics Data System (ADS)

    Vögtli, Melanie; Lehmann, Peter; Breitenstein, Daniel; Or, Dani

    2014-05-01

    Gravity driven mass release is often triggered abruptly with limited precursory cues to indicate imminent failure and thus limiting early warning. Evidence suggests that with increased mechanical loading of a slope, numerous local damage events marking friction between rearranged particles or breakage of roots release strain energy as elastic waves measurable as acoustic emissions. We examined the potential predictability of mass release events from preceding acoustic emission (AE) signatures in a well-known and simple model system of a growing sand pile. We installed four AE-sensors within the core of a 30 cm (diameter) sand pile fed by a constant input of grains and mounted on a balance. Subsequent to the convergence of the slope to dynamic angle of repose, sand avalanche across the bottom boundary were monitored by abrupt mass change and by the amplitudes and number of AE events (recorded at high frequency and averaged to 0.2 s). We detected a systematic change of AE-patterns characterized by systematically decreasing AE standard deviation prior to each mass release. Although the lead time following minimum AE standard deviation was relatively short (10s of seconds), the AE signature already started to change minutes before the mass release. Accordingly the information embedded in AE signal dynamics could potentially offer larger lead times for systems of practical interest.

  12. Spatial and Temporal Patterns of Carbon Storage in Forest Ecosystems on Hainan Island, Southern China

    PubMed Central

    Tang, Xuli; Zhang, Qianmei; Wang, Dong; Yuan, Lianlian; Chen, Xubing

    2014-01-01

    Spatial and temporal patterns of carbon (C) storage in forest ecosystems significantly affect the terrestrial C budget, but such patterns are unclear in the forests in Hainan Province, the largest tropical island in China. Here, we estimated the spatial and temporal patterns of C storage from 1993–2008 in Hainan's forest ecosystems by combining our measured data with four consecutive national forest inventories data. Forest coverage increased from 20.7% in the 1950s to 56.4% in the 2010s. The average C density of 163.7 Mg C/ha in Hainan's forest ecosystems in this study was slightly higher than that of China's mainland forests, but was remarkably lower than that in the tropical forests worldwide. Total forest ecosystem C storage in Hainan increased from 109.51 Tg in 1993 to 279.17 Tg in 2008. Soil C accounted for more than 70% of total forest ecosystem C. The spatial distribution of forest C storage in Hainan was uneven, reflecting differences in land use change and forest management. The potential carbon sequestration of forest ecosystems was 77.3 Tg C if all forested lands were restored to natural tropical forests. To increase the C sequestration potential on Hainan Island, future forest management should focus on the conservation of natural forests, selection of tree species, planting of understory species, and implementation of sustainable practices. PMID:25229628

  13. Distinct Mechanisms for Synchronization and Temporal Patterning of Odor-Encoding Neural Assemblies

    NASA Astrophysics Data System (ADS)

    MacLeod, Katrina; Laurent, Gilles

    1996-11-01

    Stimulus-evoked oscillatory synchronization of neural assemblies and temporal patterns of neuronal activity have been observed in many sensory systems, such as the visual and auditory cortices of mammals or the olfactory system of insects. In the locust olfactory system, single odor puffs cause the immediate formation of odor-specific neural assemblies, defined both by their transient synchronized firing and their progressive transformation over the course of a response. The application of an antagonist of ionotropic ?-aminobutyric acid (GABA) receptors to the first olfactory relay neuropil selectively blocked the fast inhibitory synapse between local and projection neurons. This manipulation abolished the synchronization of the odor-coding neural ensembles but did not affect each neuron's temporal response patterns to odors, even when these patterns contained periods of inhibition. Fast GABA-mediated inhibition, therefore, appears to underlie neuronal synchronization but not response tuning in this olfactory system. The selective desynchronization of stimulus-evoked oscillating neural assemblies in vivo is now possible, enabling direct functional tests of their significance for sensation and perception.

  14. Vision based forest smoke detection using analyzing of temporal patterns of smoke and their probability models

    NASA Astrophysics Data System (ADS)

    Ham, SunJae; Ko, Byoung-Chul; Nam, Jae-Yeal

    2011-03-01

    In general, since smoke appears before flames, smoke detection is particularly important for early fire detection systems. To detect fire-smoke using video camera is a difficult work because main characteristics of a smoke are uncertain, vague, constant patterns of shape and color. Thus, this paper proposes a new fire-smoke detection method, especially forest smoke using analyzing of temporal patterns of smoke and Fuzzy Finite Automata (FFA). To consider the smoke characteristics over time, the temporal patterns of intensity entropy, wavelet energy and motion orientation have been used for generating, multivariate probability density functions (PDFs) are applied Fuzzy Finite Automata (FFA) for smoke verification. The proposed FFA consist of a set of fuzzy states (VH, H, L, VL), and a transition mapping that describes what event can occur at which state and resulting new state. For smoke verification, FFA is most appropriate method in case variables are time-dependent and uncertain. The proposed algorithm is successfully applied to various fire-smoke videos and shows a better detection performance.

  15. The impact of spatial and temporal patterns on multi-cellular behavior

    NASA Astrophysics Data System (ADS)

    Nikolic, Djordje L.

    What makes a fruit fly a fruit fly? Essentially this question stems from one of the most fascinating problems in biology: how a single cell (fertilized egg) can give rise to a fully grown animal. To be able to answer this question, the importance to how spatial and temporal patterns of gene and protein expression influence the development of an organism must be understood. After all, fruit fly larvae are segmented, while fertilized eggs are not. Pattern formation is fundamental to establishing this organization of the developing embryo with the ultimate goal being the precise arrangements of specialized cells and tissues within each organ in an adult organism. The research presented here showcases the examples of studies that assess the impact spatial and temporal protein patterns have on the behavior of a collection of cells. By introducing new experimental, non-traditional techniques we developed model systems that allowed us to examine the dependence of the strength of adhesion of cells on the protein organization on sub-cellular, micron length scales, and to investigate how epithelial cell sheets coordinate their migration incorporating individual cell locomotion, molecular signal propagation and different boundary conditions. The first part of this dissertation presents a photolithography-based silanization patterning technique that allowed us to homogeneously pattern large areas with high precision. This method is then applied to organizing cell adhesion-promoting proteins on surfaces for the purposes of studying and manipulating cell behavior. We show how the strength of adhesion is dependent on high local density of an adhesive extracellular matrix protein fibronectin. The varied appeal of this technique is exhibited by showing its applicability to pattern stretched DNA, too. The second part of this dissertation focuses on the impact of spatial and temporal propagation of a molecular signal (ERK 1/2 MAPK) in migrating epithelial sheets during wound healing. By tracking the motion of individual cells within the sheet under the three constructed conditions, we show how the dynamics of the individual cells' motion is responsible for the coordinated migration of the sheet in accordance with the activation of ERK 1/2 MAPK.

  16. Acoustic Emission Patterns and the Transition to Ductility in Sub-Micron Scale Laboratory Earthquakes

    NASA Astrophysics Data System (ADS)

    Ghaffari, H.; Xia, K.; Young, R.

    2013-12-01

    We report observation of a transition from the brittle to ductile regime in precursor events from different rock materials (Granite, Sandstone, Basalt, and Gypsum) and Polymers (PMMA, PTFE and CR-39). Acoustic emission patterns associated with sub-micron scale laboratory earthquakes are mapped into network parameter spaces (functional damage networks). The sub-classes hold nearly constant timescales, indicating dependency of the sub-phases on the mechanism governing the previous evolutionary phase, i.e., deformation and failure of asperities. Based on our findings, we propose that the signature of the non-linear elastic zone around a crack tip is mapped into the details of the evolutionary phases, supporting the formation of a strongly weak zone in the vicinity of crack tips. Moreover, we recognize sub-micron to micron ruptures with signatures of 'stiffening' in the deformation phase of acoustic-waveforms. We propose that the latter rupture fronts carry critical rupture extensions, including possible dislocations faster than the shear wave speed. Using 'template super-shear waveforms' and their network characteristics, we show that the acoustic emission signals are possible super-shear or intersonic events. Ref. [1] Ghaffari, H. O., and R. P. Young. "Acoustic-Friction Networks and the Evolution of Precursor Rupture Fronts in Laboratory Earthquakes." Nature Scientific reports 3 (2013). [2] Xia, Kaiwen, Ares J. Rosakis, and Hiroo Kanamori. "Laboratory earthquakes: The sub-Rayleigh-to-supershear rupture transition." Science 303.5665 (2004): 1859-1861. [3] Mello, M., et al. "Identifying the unique ground motion signatures of supershear earthquakes: Theory and experiments." Tectonophysics 493.3 (2010): 297-326. [4] Gumbsch, Peter, and Huajian Gao. "Dislocations faster than the speed of sound." Science 283.5404 (1999): 965-968. [5] Livne, Ariel, et al. "The near-tip fields of fast cracks." Science 327.5971 (2010): 1359-1363. [6] Rycroft, Chris H., and Eran Bouchbinder. "Fracture Toughness of Metallic Glasses: Annealing-Induced Embrittlement." Physical review letters 109.19 (2012): 194301. [7] Buehler, Markus J., Farid F. Abraham, and Huajian Gao. "Hyperelasticity governs dynamic fracture at a critical length scale." Nature 426.6963 (2003): 141-146.

  17. PURPOSE: To assess the developmental pattern of vowel acoustics in individuals with Down syndrome (DS) as compared to typically

    E-print Network

    Vorperian, Houri K.

    PURPOSE: To assess the developmental pattern of vowel acoustics in individuals with Down syndrome children and children with Down syndrome Allison Petska, Houri K. Vorperian, and Ray D. Kent Vocal Tract: University of Alberta. Kent, R.D. and Vorperian, H.K. (2013). Speech Impairment in Down Syndrome: A Review. J

  18. Global Spatio-temporal Patterns of Influenza in the Post-pandemic Era.

    PubMed

    He, Daihai; Lui, Roger; Wang, Lin; Tse, Chi Kong; Yang, Lin; Stone, Lewi

    2015-01-01

    We study the global spatio-temporal patterns of influenza dynamics. This is achieved by analysing and modelling weekly laboratory confirmed cases of influenza A and B from 138 countries between January 2006 and January 2015. The data were obtained from FluNet, the surveillance network compiled by the the World Health Organization. We report a pattern of skip-and-resurgence behavior between the years 2011 and 2013 for influenza H1N1pdm, the strain responsible for the 2009 pandemic, in Europe and Eastern Asia. In particular, the expected H1N1pdm epidemic outbreak in 2011/12 failed to occur (or "skipped") in many countries across the globe, although an outbreak occurred in the following year. We also report a pattern of well-synchronized wave of H1N1pdm in early 2011 in the Northern Hemisphere countries, and a pattern of replacement of strain H1N1pre by H1N1pdm between the 2009 and 2012 influenza seasons. Using both a statistical and a mechanistic mathematical model, and through fitting the data of 108 countries, we discuss the mechanisms that are likely to generate these events taking into account the role of multi-strain dynamics. A basic understanding of these patterns has important public health implications and scientific significance. PMID:26046930

  19. Global Spatio-temporal Patterns of Influenza in the Post-pandemic Era

    PubMed Central

    He, Daihai; Lui, Roger; Wang, Lin; Tse, Chi Kong; Yang, Lin; Stone, Lewi

    2015-01-01

    We study the global spatio-temporal patterns of influenza dynamics. This is achieved by analysing and modelling weekly laboratory confirmed cases of influenza A and B from 138 countries between January 2006 and January 2015. The data were obtained from FluNet, the surveillance network compiled by the the World Health Organization. We report a pattern of skip-and-resurgence behavior between the years 2011 and 2013 for influenza H1N1pdm, the strain responsible for the 2009 pandemic, in Europe and Eastern Asia. In particular, the expected H1N1pdm epidemic outbreak in 2011/12 failed to occur (or “skipped”) in many countries across the globe, although an outbreak occurred in the following year. We also report a pattern of well-synchronized wave of H1N1pdm in early 2011 in the Northern Hemisphere countries, and a pattern of replacement of strain H1N1pre by H1N1pdm between the 2009 and 2012 influenza seasons. Using both a statistical and a mechanistic mathematical model, and through fitting the data of 108 countries, we discuss the mechanisms that are likely to generate these events taking into account the role of multi-strain dynamics. A basic understanding of these patterns has important public health implications and scientific significance. PMID:26046930

  20. Identification of unaspirated plosives using integrated temporal and spectral features in dynamic representation as acoustic cues

    Microsoft Academic Search

    D. Yeung; C. Chan

    1985-01-01

    Using a set of integrated temporal and spectral features to parameterize the consonant regions of C-V syllables, natural Mandarin unaspirated plosives \\/b\\/,\\/d\\/,\\/g\\/,\\/j\\/,\\/zh\\/, and \\/z\\/ were identified satisfactorily when stepwise discriminant function analysis was employed for classification. Out of several different parametric representation methods used, it was found that the highest overall percentage of correct recognition was reached if a dynamic

  1. Spontaneous Firings of Carnivorous Aquatic Utricularia Traps: Temporal Patterns and Mechanical Oscillations

    PubMed Central

    Vincent, Olivier; Roditchev, Ivan; Marmottant, Philippe

    2011-01-01

    Aquatic species of Utricularia are carnivorous plants living in environments poor in nutrients. Their trapping mechanism has fascinated generations of scientists and is still debated today. It was reported recently that Utricularia traps can fire spontaneously. We show here that these spontaneous firings follow an unexpected diversity of temporal patterns, from “metronomic” traps which fire at fixed time intervals to “random” patterns, displaying more scattered firing times. Some “bursting” traps even combine both aspects, with groups of fast regular firings separated by a variable amount of time. We propose a physical model to understand these very particular behaviors, showing that a trap of Utricularia accomplishes mechanical oscillations, based on continuous pumping and sudden opening of the trap door (buckling). We isolate the key parameters governing these oscillations and discuss the effect of their fluctuations. PMID:21647417

  2. Power-law Relationship in Describing Temporal and Spatial Precipitation Pattern in Turkey

    NASA Astrophysics Data System (ADS)

    Kadi?lu, M.; ?en, Z.

    Wet and dry spell properties of monthly rainfall series at five meteorology stations in Turkey are examined by plotting successive wet and dry month duration versus their number of occurrences on the double-logarithmic paper. Straight line relationships on such graphs show that power-laws govern the pattern of successive persistent wet and dry monthly spells. Functional power law relationships between the number of dry and wet spells for a given monthly period are derived from the available monthly precipitation data. The probability statements for wet and dry period spells are obtained from the power law expressions. Comparison of power-law behaviours at five distinct sites in Turkey provides useful interpretation about the temporal and spatial rainfall pattern. As in temperate areas such as Turkey the rainfall amounts change mostly due to one-month-long dry or wet spells.

  3. Measuring the scaling properties of temporal and spatial patterns: from the human eye to the foraging albatross

    E-print Network

    Taylor, Richard

    Measuring the scaling properties of temporal and spatial patterns: from the human eye, we will move on to a physical system ­ movements of the human eye as a person looks at patterns projected on a screen. The human eye is chosen because it highlights the challenges of interpreting real

  4. Fire, native species, and soil resource interactions influence the spatio-temporal invasion pattern of Bromus tectorum

    Microsoft Academic Search

    Michael J. Gundale; Steve Sutherland; Thomas H. DeLuca

    2008-01-01

    Bromus tectorum (cheatgrass) is an invasive annual that occupies perennial grass and shrub communities throughout the western United States. Bromus tectorum exhibits an intriguing spatio-temporal pattern of invasion in low elevation ponderosa pine Pinus ponderosa\\/bunchgrass communities in western Montana where it forms dense rings beneath solitary pines following fire. This pattern provides a unique opportunity to investigate several indirect effects

  5. Deriving spatio-temporal profiles of global forest fragmentation and disturbance patterns from the latest globcover datasets

    Microsoft Academic Search

    Mingshi Li; Chaoqun Jiang; Chunhong Wang; Lin Cao; Jinsong Dai

    2011-01-01

    Changes in forest fragmentation and disturbance patterns are essential for assessing the effectiveness of forest management approaches and are currently of primary concern for conservation communities. Based on the temporal Globcover datasets for 2005 and 2009, this analysis quantifies and compares forest fragmentation and disturbance patterns in the six inhabitated continents of the world by employing a fragmentation model in

  6. Self-Organization of Spatio-Temporal Hierarchy via Learning of Dynamic Visual Image Patterns on Action Sequences

    PubMed Central

    Jung, Minju; Hwang, Jungsik; Tani, Jun

    2015-01-01

    It is well known that the visual cortex efficiently processes high-dimensional spatial information by using a hierarchical structure. Recently, computational models that were inspired by the spatial hierarchy of the visual cortex have shown remarkable performance in image recognition. Up to now, however, most biological and computational modeling studies have mainly focused on the spatial domain and do not discuss temporal domain processing of the visual cortex. Several studies on the visual cortex and other brain areas associated with motor control support that the brain also uses its hierarchical structure as a processing mechanism for temporal information. Based on the success of previous computational models using spatial hierarchy and temporal hierarchy observed in the brain, the current report introduces a novel neural network model for the recognition of dynamic visual image patterns based solely on the learning of exemplars. This model is characterized by the application of both spatial and temporal constraints on local neural activities, resulting in the self-organization of a spatio-temporal hierarchy necessary for the recognition of complex dynamic visual image patterns. The evaluation with the Weizmann dataset in recognition of a set of prototypical human movement patterns showed that the proposed model is significantly robust in recognizing dynamically occluded visual patterns compared to other baseline models. Furthermore, an evaluation test for the recognition of concatenated sequences of those prototypical movement patterns indicated that the model is endowed with a remarkable capability for the contextual recognition of long-range dynamic visual image patterns. PMID:26147887

  7. Spatio-temporal pattern of vestibular information processing after brief caloric stimulation.

    PubMed

    Marcelli, Vincenzo; Esposito, Fabrizio; Aragri, Adriana; Furia, Teresa; Riccardi, Pasquale; Tosetti, Michela; Biagi, Laura; Marciano, Elio; Di Salle, Francesco

    2009-05-01

    Processing of vestibular information at the cortical and subcortical level is essential for head and body orientation in space and self-motion perception, but little is known about the neural dynamics of the brain regions of the vestibular system involved in this task. Neuroimaging studies using both galvanic and caloric stimulation have shown that several distinct cortical and subcortical structures can be activated during vestibular information processing. The insular cortex has been often targeted and presented as the central hub of the vestibular cortical system. Since very short pulses of cold water ear irrigation can generate a strong and prolonged vestibular response and a nystagmus, we explored the effects of this type of caloric stimulation for assessing the blood-oxygen-level-dependent (BOLD) dynamics of neural vestibular processing in a whole-brain event-related functional magnetic resonance imaging (fMRI) experiment. We evaluated the spatial layout and the temporal dynamics of the activated cortical and subcortical regions in time-locking with the instant of injection and were able to extract a robust pattern of neural activity involving the contra-lateral insular cortex, the thalamus, the brainstem and the cerebellum. No significant correlation with the temporal envelope of the nystagmus was found. The temporal analysis of the activation profiles highlighted a significantly longer duration of the evoked BOLD activity in the brainstem compared to the insular cortex suggesting a functional de-coupling between cortical and subcortical activity during the vestibular response. PMID:18342473

  8. Comprehensive common spatial patterns with temporal structure information of EEG data: minimizing nontask related EEG component.

    PubMed

    Wang, Haixian; Xu, Dong

    2012-09-01

    In the context of electroencephalogram (EEG)-based brain-computer interfaces (BCI), common spatial patterns (CSP) is widely used for spatially filtering multichannel EEG signals. CSP is a supervised learning technique depending on only labeled trials. Its generalization performance deteriorates due to overfitting occurred when the number of training trials is small. On the other hand, a large number of unlabeled trials are relatively easy to obtain. In this paper, we contribute a comprehensive learning scheme of CSP (cCSP) that learns on both labeled and unlabeled trials. cCSP regularizes the objective function of CSP by preserving the temporal relationship among samples of unlabeled trials in terms of linear representation. The intrinsically temporal structure is characterized by an l(1) graph. As a result, the temporal correlation information of unlabeled trials is incorporated into CSP, yielding enhanced generalization capacity. Interestingly, the regularizer of cCSP can be interpreted as minimizing a nontask related EEG component, which helps cCSP alleviate nonstationarities. Experiment results of single-trial EEG classification on publicly available EEG datasets confirm the effectiveness of the proposed method. PMID:22736634

  9. Temporal vocal features suggest different call-pattern generating mechanisms in mice and bats

    PubMed Central

    2013-01-01

    Background Mice produce ultrasonic vocalizations in various inter-individual encounters and with high call rates. However, it is so far virtually unknown how these vocal patterns are generated. On the one hand, these vocal patterns could be embedded into the normal respiratory cycle, as happens in bats and other mammals that produce similar call rates and frequencies. On the other, mice could possess distinct vocal pattern generating systems that are capable of modulating the respiratory cycle, which is what happens in non-human and human primates. In the present study, we investigated the temporal call patterns of two different mammalian species, bats and mice, in order to differentiate between these two possibilities for mouse vocalizations. Our primary focus was on comparing the mechanisms for the production of rapid, successive ultrasound calls of comparable frequency ranges in the two species. Results We analyzed the temporal call pattern characteristics of mice, and we compared these characteristics to those of ultrasonic echolocation calls produced by horseshoe bats. We measured the distributions of call durations, call intervals, and inter-call intervals in the two species. In the bat, and consistent with previous studies, we found that call duration was independent of corresponding call intervals, and that it was negatively correlated with the corresponding inter-call interval. This indicates that echolocation call production mechanisms in the bat are highly correlated with the respiratory cycle. In contrast, call intervals in the mouse were directly correlated with call duration. Importantly, call duration was not, or was only slightly, correlated with inter-call intervals, consistent with the idea that vocal production in the mouse is largely independent of the respiratory cycle. Conclusions Our findings suggest that ultrasonic vocalizations in mice are produced by call-pattern generating mechanisms that seem to be similar to those that have been found in primates. This is in contrast to the production mechanisms of ultrasonic echolocation calls in horseshoe bats. These results are particularly interesting, especially since mouse vocalizations have recently attracted increased attention as potential indicators for the degree of progression of several disease patterns in mouse models for neurodegenerative and neurodevelopmental disorders of humans. PMID:24020588

  10. Population dynamics of wetland fishes: Spatio-temporal patterns synchronized by hydrological disturbance?

    USGS Publications Warehouse

    Ruetz, C. R., III; Trexler, J.C.; Jordan, F.; Loftus, W.F.; Perry, S.A.

    2005-01-01

    1. Drought is a natural disturbance that can cause widespread mortality of aquatic organisms in wetlands. We hypothesized that seasonal drying of marsh surfaces (i.e. hydrological disturbance) shapes spatio-temporal patterns of fish populations. 2. We tested whether population dynamics of fishes were synchronized by hydrological disturbance (Moran effect) or distance separating study sites (dispersal). Spatio-temporal patterns were examined in local populations of five abundant species at 17 sites (sampled five times per year from 1996 to 2001) in a large oligotrophic wetland. 3. Fish densities differed significantly across spatio-temporal scales for all species. For all species except eastern mosquitofish (Gambusia holbrooki), a significant portion of spatio-temporal variation in density was attributed to drying events (used as a covariate). 4. We observed three patterns of response to hydrological disturbance. Densities of bluefin killifish (Lucania goodei), least killifish (Heterandria formosa), and golden top-minnow (Fundulus chrysotus) were usually lowest after a dry down and recovered slowly. Eastern mosquitofish showed no distinct response to marsh drying (i.e. they recovered quickly). Flagfish (Jordanella floridae) density was often highest after a dry down and then declined. Population growth after a dry down was often asymptotic for bluefin killifish and golden topminnow, with greatest asymptotic density and longest time to recovery at sites that dried infrequently. 5. Fish population dynamics were synchronized by hydrological disturbance (independent of distance) and distance separating study sites (independent of hydrological disturbance). Our ability to separate the relative importance of the Moran effect from dispersal was strengthened by a weak association between hydrological synchrony and distance among study sites. Dispersal was the primary mechanism for synchronous population dynamics of flagfish, whereas hydrological disturbance was the primary mechanism for synchronous population dynamics of the other species examined. 6. Species varied in the relative role of the Moran effect and dispersal in homogenizing their population dynamics, probably as a function of life history and ability to exploit dry-season refugia. ?? 2005 British Ecological Society.

  11. Temporal patterns of genetic and phenotypic variation in the epidemiologically important drone fly, Eristalis tenax.

    PubMed

    Francuski, Lj; Mati?, I; Ludoški, J; Milankov, V

    2011-06-01

    Eristalis tenax L. (Diptera: Syrphidae) is commonly known as the drone fly (adult) or rat-tailed maggot (immature). Both adults and immature stages are identified as potential mechanical vectors of mycobacterial pathogens, and early-stage maggots cause accidental myiasis. We compared four samples from Mount Fruška Gora, Serbia, with the aim of obtaining insights into the temporal variations and sexual dimorphism in the species. This integrative approach was based on allozyme loci, morphometric wing parameters (shape and size) and abdominal colour patterns. Consistent sexual dimorphism was observed, indicating that male specimens had lighter abdomens and smaller and narrower wings than females. The distribution of genetic diversity at polymorphic loci indicated genetic divergence among collection dates. Landmark-based geometric morphometrics revealed, contrary to the lack of divergence in wing size, significant wing shape variation throughout the year. In addition, temporal changes in the frequencies of the abdominal patterns observed are likely to relate to the biology of the species and ecological factors in the locality. Hence, the present study expands our knowledge of the genetic diversity and phenotypic plasticity of E. tenax. The quantification of such variability represents a step towards the evaluation of the adaptive potential of this species of medical and epidemiological importance. PMID:21414022

  12. Fish and phytoplankton exhibit contrasting temporal species abundance patterns in a dynamic north temperate lake.

    PubMed

    Hansen, Gretchen J A; Carey, Cayelan C

    2015-01-01

    Temporal patterns of species abundance, although less well-studied than spatial patterns, provide valuable insight to the processes governing community assembly. We compared temporal abundance distributions of two communities, phytoplankton and fish, in a north temperate lake. We used both 17 years of observed relative abundance data as well as resampled data from Monte Carlo simulations to account for the possible effects of non-detection of rare species. Similar to what has been found in other communities, phytoplankton and fish species that appeared more frequently were generally more abundant than rare species. However, neither community exhibited two distinct groups of "core" (common occurrence and high abundance) and "occasional" (rare occurrence and low abundance) species. Both observed and resampled data show that the phytoplankton community was dominated by occasional species appearing in only one year that exhibited large variation in their abundances, while the fish community was dominated by core species occurring in all 17 years at high abundances. We hypothesize that the life-history traits that enable phytoplankton to persist in highly dynamic environments may result in communities dominated by occasional species capable of reaching high abundances when conditions allow. Conversely, longer turnover times and broad environmental tolerances of fish may result in communities dominated by core species structured primarily by competitive interactions. PMID:25651399

  13. Temporal patterns of human behaviour: are there signs of deterministic 1/ f scaling?

    NASA Astrophysics Data System (ADS)

    Dünki, Rudolf M.; Keller, Elvira; Meier, Peter F.; Ambühl, Brigitte

    2000-02-01

    Temporal patterns apparently exhibiting scaling properties may originate either from fractal stochastic processes or from causal (i.e., deterministic) dynamics. In general, the distinction between the possible two origins remains a non-trivial task. This holds especially for the interpretation of properties derived from temporal patterns of various types of human behaviour, which were reported repeatedly. We propose here a computational scheme based on a generic intermittency model to test predictability (thus determinism) of a part of a time series with knowledge gathered from another part. The method is applied onto psychodynamic time series related to turns from non-psychosis to psychosis. A nonrandom correlation ( ?=0.76) between prediction and real outcome is found. Our scheme thus provides a particular kind of fractal risk-assessment for this possibly deterministic process. We briefly discuss possible implications of these findings to evaluate the risk to undergo a state transition, in our case a patients risk to enter a next psychotic state. We further point to some problems concerning data sample pecularities and equivalence between data and model setup.

  14. Fish and Phytoplankton Exhibit Contrasting Temporal Species Abundance Patterns in a Dynamic North Temperate Lake

    PubMed Central

    Hansen, Gretchen J. A.; Carey, Cayelan C.

    2015-01-01

    Temporal patterns of species abundance, although less well-studied than spatial patterns, provide valuable insight to the processes governing community assembly. We compared temporal abundance distributions of two communities, phytoplankton and fish, in a north temperate lake. We used both 17 years of observed relative abundance data as well as resampled data from Monte Carlo simulations to account for the possible effects of non-detection of rare species. Similar to what has been found in other communities, phytoplankton and fish species that appeared more frequently were generally more abundant than rare species. However, neither community exhibited two distinct groups of “core” (common occurrence and high abundance) and “occasional” (rare occurrence and low abundance) species. Both observed and resampled data show that the phytoplankton community was dominated by occasional species appearing in only one year that exhibited large variation in their abundances, while the fish community was dominated by core species occurring in all 17 years at high abundances. We hypothesize that the life-history traits that enable phytoplankton to persist in highly dynamic environments may result in communities dominated by occasional species capable of reaching high abundances when conditions allow. Conversely, longer turnover times and broad environmental tolerances of fish may result in communities dominated by core species structured primarily by competitive interactions. PMID:25651399

  15. Temporal Changes in Eruptive Behavior at Fuego Volcano, Guatemala Identified with Seismic Coda Wave Interferometry and Seismo-acoustic Observations

    NASA Astrophysics Data System (ADS)

    Erdem, J.; Waite, G. P.

    2011-12-01

    Fuego Volcano (14°29'N, 90°53'W, 3800m) is the southernmost vent of the north-south trending Fuego-Acatenango volcanic complex. A basaltic-andesite stratovolcano, Fuego has had more than 60 sub-plinian eruptions since 1524 AD, making it one of the most active volcanoes in the world. Since 1999 Fuego has exhibited continuous low-level activity, which alternates between periods of lava effusion with strombolian explosions and periods of discrete explosions with no lava effusion. We analyzed 138 explosions recorded on a broadband seismometer and infrasonic microphones from 7 to 14 June 2008 at a distance of 7.5 km from the vent. During the observation period, a new lava flow began. Additional observations were made at a distance of 1 km between 27 June and 1 July 2008. The explosions were identified through a combination of visual field observations and the examination of infrasound records. Acoustic waveform cross-correlation indicated a highly repetitive source appropriate for investigating temporal variations in the wavefield. We measured variations in seismic and acoustic wave arrival time differences in the range of 0.5 s for the more distant station, which might occur as a result of variations in source depth, for example. However, after examining a wind speed model for the region, we find that wind speed variations are more likely to explain the delays. We also detected short-term relative changes in the velocity structure ranging from -0.23% to 0.61% at the distant station and -0.8% to 0.7% at the closer station using seismic coda wave interferometry. This rapid variation, sometimes changing by 0.23% in 90 minutes, may indicate minor fluctuations in volatile content.

  16. Temporal Links in Daily Activity Patterns between Coral Reef Predators and Their Prey

    PubMed Central

    Bosiger, Yoland J.; McCormick, Mark I.

    2014-01-01

    Few studies have documented the activity patterns of both predators and their common prey over 24 h diel cycles. This study documents the temporal periodicity of two common resident predators of juvenile reef fishes, Cephalopholis cyanostigma (rockcod) and Pseudochromis fuscus (dottyback) and compares these to the activity and foraging pattern of a common prey species, juvenile Pomacentrus moluccensis (lemon damselfish). Detailed observations of activity in the field and using 24 h infrared video in the laboratory revealed that the two predators had very different activity patterns. C. cyanostigma was active over the whole 24 h period, with a peak in feeding strikes at dusk and increased activity at both dawn and dusk, while P. fuscus was not active at night and had its highest strike rates at midday. The activity and foraging pattern of P. moluccensis directly opposes that of C. cyanostigma with individuals reducing strike rate and intraspecific aggression at both dawn and dusk, and reducing distance from shelter and boldness at dusk only. Juveniles examined were just outside the size-selection window of P. fuscus. We suggest that the relatively predictable diel behaviour of coral reef predators results from physiological factors such as visual sensory abilities, circadian rhythmicity, variation in hunting profitability, and predation risk at different times of the day. Our study suggests that the diel periodicity of P. moluccensis behaviour may represent a response to increased predation risk at times when both the ability to efficiently capture food and visually detect predators is reduced. PMID:25354096

  17. Spatio-Temporal Patterns of Key Exploited Marine Species in the Northwestern Mediterranean Sea

    PubMed Central

    Morfin, Marie; Fromentin, Jean-Marc; Jadaud, Angélique; Bez, Nicolas

    2012-01-01

    This study analyzes the temporal variability/stability of the spatial distributions of key exploited species in the Gulf of Lions (Northwestern Mediterranean Sea). To do so, we analyzed data from the MEDITS bottom-trawl scientific surveys from 1994 to 2010 at 66 fixed stations and selected 12 key exploited species. We proposed a geostatistical approach to handle zero-inflated and non-stationary distributions and to test for the temporal stability of the spatial structures. Empirical Orthogonal Functions and other descriptors were then applied to investigate the temporal persistence and the characteristics of the spatial patterns. The spatial structure of the distribution (i.e. the pattern of spatial autocorrelation) of the 12 key species studied remained highly stable over the time period sampled. The spatial distributions of all species obtained through kriging also appeared to be stable over time, while each species displayed a specific spatial distribution. Furthermore, adults were generally more densely concentrated than juveniles and occupied areas included in the distribution of juveniles. Despite the strong persistence of spatial distributions, we also observed that the area occupied by each species was correlated to its abundance: the more abundant the species, the larger the occupation area. Such a result tends to support MacCall's basin theory, according to which density-dependence responses would drive the expansion of those 12 key species in the Gulf of Lions. Further analyses showed that these species never saturated their habitats, suggesting that they are below their carrying capacity; an assumption in agreement with the overexploitation of several of these species. Finally, the stability of their spatial distributions over time and their potential ability to diffuse outside their main habitats give support to Marine Protected Areas as a potential pertinent management tool. PMID:22655079

  18. Spatio-temporal patterns of key exploited marine species in the Northwestern Mediterranean Sea.

    PubMed

    Morfin, Marie; Fromentin, Jean-Marc; Jadaud, Angélique; Bez, Nicolas

    2012-01-01

    This study analyzes the temporal variability/stability of the spatial distributions of key exploited species in the Gulf of Lions (Northwestern Mediterranean Sea). To do so, we analyzed data from the MEDITS bottom-trawl scientific surveys from 1994 to 2010 at 66 fixed stations and selected 12 key exploited species. We proposed a geostatistical approach to handle zero-inflated and non-stationary distributions and to test for the temporal stability of the spatial structures. Empirical Orthogonal Functions and other descriptors were then applied to investigate the temporal persistence and the characteristics of the spatial patterns. The spatial structure of the distribution (i.e. the pattern of spatial autocorrelation) of the 12 key species studied remained highly stable over the time period sampled. The spatial distributions of all species obtained through kriging also appeared to be stable over time, while each species displayed a specific spatial distribution. Furthermore, adults were generally more densely concentrated than juveniles and occupied areas included in the distribution of juveniles. Despite the strong persistence of spatial distributions, we also observed that the area occupied by each species was correlated to its abundance: the more abundant the species, the larger the occupation area. Such a result tends to support MacCall's basin theory, according to which density-dependence responses would drive the expansion of those 12 key species in the Gulf of Lions. Further analyses showed that these species never saturated their habitats, suggesting that they are below their carrying capacity; an assumption in agreement with the overexploitation of several of these species. Finally, the stability of their spatial distributions over time and their potential ability to diffuse outside their main habitats give support to Marine Protected Areas as a potential pertinent management tool. PMID:22655079

  19. Molecular Dynamics Simulations of Surface Acoustic Waves on Patterned Layered Nanostructures

    NASA Astrophysics Data System (ADS)

    Bjornsson, Matteo; Connolly, Aine; Mahat, Sushant; Rachmilowitz, Bryan; Daly, Brian; Antonelli, George; Myers, Alan; Singh, Kanwal; Yoo, Hiu-Jae; King, Sean

    2015-03-01

    We report coarse-grained molecular dynamics (MD) simulations of surface acoustic waves on patterned layered nanostructures. The simulations were designed for comparison with samples consisting of the following patterned film stack: 25 nm physically vapor deposited TiN / 180 nm porous PECVD-grown a-SiOC:H / 12 nm non-porous PECVD-grown a-SiOC:H etch-stop / 100 nm CVD-grown a-SiO2 / Si (100) substrate. The TiN film was etched with lines of rectangular cross-section with pitch = 168 to 420 nm. Ultrafast optical experiments on these samples have detected high frequency surface waves in the range of 10's of GHz. The MD simulation demonstrates the presence of strongly excited modes at frequencies that closely match those found in the experiments. Moreover, the simulation predicts that the type of surface wave mode detected should change depending on the pitch. For larger pitch, Rayleigh-like waves are predicted, but for smaller pitch, Sezawa waves (surface waves with properties similar to free plate modes of the thin films) are predicted. The MD simulation also demonstrates the cutoff wavelength for the Sezawa modes, as is reflected in the experimental results and as is also predicted by isotropic elastic calculations of the surface modes of a thin film on an infinite substrate. This work was supported by NSF Award DMR1206681.

  20. Imaging Spatial and Temporal Patterns of Landslide Movement with Ground-Based Radar Interferometry

    NASA Astrophysics Data System (ADS)

    Gomez, F.; Held, B. M.; Lowry, B. W.; Mooney, M.; Zhou, W.; Grasmick, J.

    2012-12-01

    Ground-based interferometric radar (GBIR) provides a means of addressing questions about landslides that involve monitoring changes across large areas (<10 km2) with high spatial (<1 mm) and temporal precision (<1 hr). Recent studies have shown that landslide displacement rates may exhibit sensitivity to unlikely sources, such as atmospheric tides. This study applies GBIR to measure temporal and spatial patterns of movement in a slow-velocity slide on the west side of the Colorado Front Range. Multiple deployments of the GBIR permit assessing long-term (seasonal) variations in slide kinematics, which compared favorably with ground-truth measurements using more conventional surveying techniques. Each GBIR deployment involves long observation sessions (5 - 36 hours) with images acquired every 7.5 - 15 minutes. The data redundancy permits rigorous time-series analysis that results in 0.3 - 0.4 mm positional uncertainties. The time series is further constrained by imposing a 'no back-slip' condition that is justified by the nearly horizontal viewing geometry facing in the slide's direction of transport. The slide demonstrates significant seasonal variations that correspond with variations in groundwater measured by piezometric wells in the study area. These are primarily driven by variations in spring snow melt and precipitation. Additionally, short-span time series for individual observation sessions suggest short term variations in displacement rate over periods of several hours. One possible model for this quasi stick-slip behavior may involve release of excess fluid pressure during slide movement that increases frictional coupling at the base of the slide. As a tool for geodetic imaging, offers a significant improvement in temporal and spatial resolution compared with satellite and airborne radar interferometry. The sensitivity and temporal sampling of GBIR complement well the spatial resolution and 3-dimensional displacements measured with other methods, such as terrestrial laser scanners.

  1. The Chronotron: A Neuron That Learns to Fire Temporally Precise Spike Patterns

    PubMed Central

    Florian, R?zvan V.

    2012-01-01

    In many cases, neurons process information carried by the precise timings of spikes. Here we show how neurons can learn to generate specific temporally precise output spikes in response to input patterns of spikes having precise timings, thus processing and memorizing information that is entirely temporally coded, both as input and as output. We introduce two new supervised learning rules for spiking neurons with temporal coding of information (chronotrons), one that provides high memory capacity (E-learning), and one that has a higher biological plausibility (I-learning). With I-learning, the neuron learns to fire the target spike trains through synaptic changes that are proportional to the synaptic currents at the timings of real and target output spikes. We study these learning rules in computer simulations where we train integrate-and-fire neurons. Both learning rules allow neurons to fire at the desired timings, with sub-millisecond precision. We show how chronotrons can learn to classify their inputs, by firing identical, temporally precise spike trains for different inputs belonging to the same class. When the input is noisy, the classification also leads to noise reduction. We compute lower bounds for the memory capacity of chronotrons and explore the influence of various parameters on chronotrons' performance. The chronotrons can model neurons that encode information in the time of the first spike relative to the onset of salient stimuli or neurons in oscillatory networks that encode information in the phases of spikes relative to the background oscillation. Our results show that firing one spike per cycle optimizes memory capacity in neurons encoding information in the phase of firing relative to a background rhythm. PMID:22879876

  2. A method for estimating the temporal and spatial patterns of carbon dioxide emissions from national fossil-fuel consumption

    Microsoft Academic Search

    J. S. Gregg; Robert Joseph Andres

    2008-01-01

    A proportional methodology is presented for estimating fossil-fuel consumption and concomitant anthropogenic carbon dioxide (CO2) emissions. This methodology employs data from representative sectors of the fossil-fuel market to determine the temporal (monthly) and spatial (provincial\\/state) patterns of fuel consumption. These patterns of fuel consumption are then converted to patterns of CO2 emissions. The purpose is to provide a procedure for

  3. The Use of Census Migration Data to Approximate Human Movement Patterns across Temporal Scales

    PubMed Central

    Wesolowski, Amy; Buckee, Caroline O.; Pindolia, Deepa K.; Eagle, Nathan; Smith, David L.; Garcia, Andres J.; Tatem, Andrew J.

    2013-01-01

    Human movement plays a key role in economies and development, the delivery of services, and the spread of infectious diseases. However, it remains poorly quantified partly because reliable data are often lacking, particularly for low-income countries. The most widely available are migration data from human population censuses, which provide valuable information on relatively long timescale relocations across countries, but do not capture the shorter-scale patterns, trips less than a year, that make up the bulk of human movement. Census-derived migration data may provide valuable proxies for shorter-term movements however, as substantial migration between regions can be indicative of well connected places exhibiting high levels of movement at finer time scales, but this has never been examined in detail. Here, an extensive mobile phone usage data set for Kenya was processed to extract movements between counties in 2009 on weekly, monthly, and annual time scales and compared to data on change in residence from the national census conducted during the same time period. We find that the relative ordering across Kenyan counties for incoming, outgoing and between-county movements shows strong correlations. Moreover, the distributions of trip durations from both sources of data are similar, and a spatial interaction model fit to the data reveals the relationships of different parameters over a range of movement time scales. Significant relationships between census migration data and fine temporal scale movement patterns exist, and results suggest that census data can be used to approximate certain features of movement patterns across multiple temporal scales, extending the utility of census-derived migration data. PMID:23326367

  4. Spatial and temporal exposure patterns in non-target small mammals during brodifacoum rat control.

    PubMed

    Geduhn, Anke; Esther, Alexandra; Schenke, Detlef; Mattes, Hermann; Jacob, Jens

    2014-10-15

    Worldwide pest rodents on livestock farms are often regulated using anticoagulant rodenticides (ARs). Second generation ARs in particular can cause poisoning in non-target species due to their high toxicity and persistence. However, research on exposure of small mammals is rare. We systematically investigated spatial and temporal exposure patterns of non-target small mammals in a large-scale replicated study. Small mammals were trapped at different distances to bait stations on ten farms before, during and after brodifacoum (BR) bait application, and liver samples of 1178 non-target small mammals were analyzed for residues of eight ARs using liquid chromatography coupled with tandem mass spectrometry. BR residues were present in 23% out of 742 samples collected during and after baiting. We found clear spatial and temporal exposure patterns. High BR residue concentrations mainly occurred within 15m from bait stations. Occurrence and concentrations of residues significantly decreased with increasing distance. This pattern was found in almost all investigated taxa. After baiting, significantly more individuals contained residues than during baiting but concentrations were considerably lower. Residue occurrence and concentrations differed significantly among taxa, with the highest maximal residue concentrations in Apodemus species, which are protected in Germany. Although Sorex species are known to be insectivorous we regularly found residues in this genus. Residues of active agents other than brodifacoum were rare in all samples. The confirmation of substantial primary exposure in non-target small mammals close to the baiting area indicates considerable risk of secondary poisoning of predators, a pathway that was possibly underestimated until now. Our results will help to develop risk mitigation strategies to reduce risk for non-target small mammals, as well as their predators, in relation to biocidal AR usage. PMID:25087064

  5. Optimization of the temporal pattern of radiation: An IMRT based study

    SciTech Connect

    Altman, Michael B. [Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL (United States); Chmura, Steven J. [Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL (United States); Deasy, Joseph O. [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO (United States); Roeske, John C. [Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL (United States)]. E-mail: roeske@rover.uchicago.edu

    2006-11-01

    Purpose: To investigate how the temporal pattern of dose applied during a single-intensity modulated radiation therapy (IMRT) fraction can be arranged to maximize or minimize cell kill. Methods and Materials: Using the linear-quadratic repair-time model and a simplified IMRT delivery pattern model, the surviving fraction of cells for a single fraction was calculated for all permutations of the dose delivery pattern for an array of clinically based IMRT cases. Maximization of cell kill was achieved by concentrating the highest doses in the middle of a fraction, while minimization was achieved by spreading the highest doses between the beginning and end. The percent difference between maximum and minimum cell kill (%Diff{sub min/max}) and the difference between maximum and minimum total doses normalized to 2 Gy/fx ({delta}NTD{sub 2Gy}) was calculated for varying fraction durations (T), {alpha}/{beta} ratios, and doses/fx. Results: %Diff{sub min/max} and {delta}NTD{sub 2Gy} both increased with increasing T and with decreasing {alpha}/{beta}. The largest increases occurred with dose/fx. With {alpha}/{beta} = 3 Gy and 30 min/fx, %Diff{sub min/max} ranged from 2.7-5.3% for 2 Gy/fx to 48.6-74.1% for 10 Gy/fx, whereas {delta}NTD{sub 2Gy} ranged from 1.2 Gy-2.4 Gy for 30 fractions of 2 Gy/fx to 2.3-4.8 Gy for 2 fractions of 10.84 Gy/fx. Using {alpha}/{beta} = 1.5 Gy, an analysis of prostate hypofractionation schemes yielded differences in clinical outcome based on the pattern of applied dose ranging from 3.2%-6.1% of the treated population. Conclusions: Rearrangement of the temporal pattern of dose for a single IMRT fraction could be used to optimize cell kill and to directly, though modestly, affect treatment outcome.

  6. The spatial and temporal distributions of arthropods in forest canopies: uniting disparate patterns with hypotheses for specialisation.

    PubMed

    Wardhaugh, Carl W

    2014-11-01

    Arguably the majority of species on Earth utilise tropical rainforest canopies, and much progress has been made in describing arboreal assemblages, especially for arthropods. The most commonly described patterns for tropical rainforest insect communities are host specificity, spatial specialisation (predominantly vertical stratification), and temporal changes in abundance (seasonality and circadian rhythms). Here I review the recurrent results with respect to each of these patterns and discuss the evolutionary selective forces that have generated them in an attempt to unite these patterns in a holistic evolutionary framework. I propose that species can be quantified along a generalist-specialist scale not only with respect to host specificity, but also other spatial and temporal distribution patterns, where specialisation is a function of the extent of activity across space and time for particular species. When all of these distribution patterns are viewed through the paradigm of specialisation, hypotheses that have been proposed to explain the evolution of host specificity can also be applied to explain the generation and maintenance of other spatial and temporal distribution patterns. The main driver for most spatial and temporal distribution patterns is resource availability. Generally, the distribution of insects follows that of the resources they exploit, which are spatially stratified and vary temporally in availability. Physiological adaptations are primarily important for host specificity, where nutritional and chemical variation among host plants in particular, but also certain prey species and fungi, influence host range. Physiological tolerances of abiotic conditions are also important for explaining the spatial and temporal distributions of some insect species, especially in drier forest environments where desiccation is an ever-present threat. However, it is likely that for most species in moist tropical rainforests, abiotic conditions are valuable indicators of resource availability, rather than physiologically limiting factors. Overall, each distribution pattern is influenced by the same evolutionary forces, but at differing intensities. Consequently, each pattern is linked and not mutually exclusive of the other distribution patterns. Most studies have examined each of these patterns in isolation. Future work should focus on examining the evolutionary drivers of these patterns in concert. Only then can the relative strength of resource availability and distribution, host defensive phenotypes, and biotic and abiotic interactions on insect distribution patterns be determined. PMID:24581118

  7. Evaluation of the Temporal Acoustic Window for Transcranial Doppler in a Multi-Ethnic Population in Brazil.

    PubMed

    Bazan, Rodrigo; Braga, Gabriel Pereira; Luvizutto, Gustavo José; Hueb, João Carlos; Hokama, Newton Key; Zanati Bazan, Silméia Garcia; de Carvalho Nunes, Hélio Rubens; Leite, João Pereira; Pontes-Neto, Octávio Marques

    2015-08-01

    The aim of this study was to relate the presence of a temporal acoustic window (TAW) to the variables sex, age and race. This observational study was conducted in patients under etiologic investigation after stroke, sickle-cell anemia and hospitalization in an intensive therapy neurologic unit. TAW presence was confirmed by bilateral assessment by two neurologists via transcranial Doppler (TCD). Multiple logistic regression was performed to explain the presence of the window as a function of sex, age and race. In 20% of the 262 patients evaluated, a TAW was not present. The incidence of TAW presence was greater in men (odds ratio [OR] = 5.4, 95% confidence interval [CI] = 2.5-11.7, p < 0.01); lower with increased age (OR = 0.9, 95% CI = 0.92-0.97, p < 0.01); and lower among those of African and Asian descent (OR = 0.32, 95% CI = 0.14-0.70, p = 0.005). On the basis of the results, more men than women had TAWs, and the decrease in TAWs was associated with increased age and African or Asian descent. PMID:25964064

  8. Low-frequency vibration measurement by temporal analysis of projected fringe patterns

    NASA Astrophysics Data System (ADS)

    Fu, Yu

    2010-02-01

    Fringe projection is a whole field, non-contacting optical technique allowing direct measurement of surface contour of an object. In many cases, 3D surface profiling is required for vibrating objects or for objects with continuously changing profile, where conventional phase shifting techniques are not applicable. Carrier-based spatial Fourier, window Fourier analyses, or wavelet analysis are normally used to retrieve instantaneous phase maps in dynamic measurement from one fringe pattern, but these techniques require high-quality surface, such as uniform reflectivity, continuity of the surface and a regular shape. Otherwise, large errors will be generated during the process. In this study, a grating is projected on the surface of a low-frequency vibrating object and a sequence of fringe patterns is captured by a high-speed camera. The fringe patterns are processed point-by-point along time axis by different algorithms. To avoid the phase ambiguity problem, a temporal carrier is introduced in the experiment by shifting the grating with a constant speed. The results show that high-quality instantaneous surface profile and the kinematic parameters of vibration, such as displacement, velocity and acceleration can be obtained precisely.

  9. User Activity Recognition in Smart Homes Using Pattern Clustering Applied to Temporal ANN Algorithm.

    PubMed

    Bourobou, Serge Thomas Mickala; Yoo, Younghwan

    2015-01-01

    This paper discusses the possibility of recognizing and predicting user activities in the IoT (Internet of Things) based smart environment. The activity recognition is usually done through two steps: activity pattern clustering and activity type decision. Although many related works have been suggested, they had some limited performance because they focused only on one part between the two steps. This paper tries to find the best combination of a pattern clustering method and an activity decision algorithm among various existing works. For the first step, in order to classify so varied and complex user activities, we use a relevant and efficient unsupervised learning method called the K-pattern clustering algorithm. In the second step, the training of smart environment for recognizing and predicting user activities inside his/her personal space is done by utilizing the artificial neural network based on the Allen's temporal relations. The experimental results show that our combined method provides the higher recognition accuracy for various activities, as compared with other data mining classification algorithms. Furthermore, it is more appropriate for a dynamic environment like an IoT based smart home. PMID:26007738

  10. User Activity Recognition in Smart Homes Using Pattern Clustering Applied to Temporal ANN Algorithm

    PubMed Central

    Bourobou, Serge Thomas Mickala; Yoo, Younghwan

    2015-01-01

    This paper discusses the possibility of recognizing and predicting user activities in the IoT (Internet of Things) based smart environment. The activity recognition is usually done through two steps: activity pattern clustering and activity type decision. Although many related works have been suggested, they had some limited performance because they focused only on one part between the two steps. This paper tries to find the best combination of a pattern clustering method and an activity decision algorithm among various existing works. For the first step, in order to classify so varied and complex user activities, we use a relevant and efficient unsupervised learning method called the K-pattern clustering algorithm. In the second step, the training of smart environment for recognizing and predicting user activities inside his/her personal space is done by utilizing the artificial neural network based on the Allen’s temporal relations. The experimental results show that our combined method provides the higher recognition accuracy for various activities, as compared with other data mining classification algorithms. Furthermore, it is more appropriate for a dynamic environment like an IoT based smart home. PMID:26007738

  11. Precision phenotyping of biomass accumulation in triticale reveals temporal genetic patterns of regulation

    PubMed Central

    Busemeyer, Lucas; Ruckelshausen, Arno; Möller, Kim; Melchinger, Albrecht E.; Alheit, Katharina V.; Maurer, Hans Peter; Hahn, Volker; Weissmann, Elmar A.; Reif, Jochen C.; Würschum, Tobias

    2013-01-01

    To extend agricultural productivity by knowledge-based breeding and tailor varieties adapted to specific environmental conditions, it is imperative to improve our ability to assess the dynamic changes of the phenome of crops under field conditions. To this end, we have developed a precision phenotyping platform that combines various sensors for a non-invasive, high-throughput and high-dimensional phenotyping of small grain cereals. This platform yielded high prediction accuracies and heritabilities for biomass of triticale. Genetic variation for biomass accumulation was dissected with 647 doubled haploid lines derived from four families. Employing a genome-wide association mapping approach, two major quantitative trait loci (QTL) for biomass were identified and the genetic architecture of biomass accumulation was found to be characterized by dynamic temporal patterns. Our findings highlight the potential of precision phenotyping to assess the dynamic genetics of complex traits, especially those not amenable to traditional phenotyping. PMID:23942574

  12. Remote flow sensing of complex systems: steps towards spatio-temporal prediction of flow patterns

    NASA Astrophysics Data System (ADS)

    Monnier, Bruno; Mokhasi, Paritosh; Rempfer, Dietmar; Wark, Candace

    2009-11-01

    Prediction of the spatial and temporal phenomena of wind flow patterns through urban areas is investigated. Typically sparse measurements are used in wind forecasting models for updating and prediction via a method called variational data assimilation. To improve upon this method, an experimental investigation combining various measurement tools (Hot Wire Anemometry, Stereoscopic Particle Image Velocimetry SPIV), static pressure measurements and Laser Doppler Velocimetry(LDV)) is carried out to study the airflow around wall mounted obstacles in a turbulent boundary layer. The method of Proper Orthogonal Decomposition (POD) is used to decompose the flow field into a finite set of POD coefficients which vary only in time associated with a corresponding set of POD basis functions which vary only in space. Direct measurement models utilizing the measurements from SPIV and LDV, along with indirect measurement models using sparse measurements from microphones are investigated and may ultimately be combined with state-space models to obtain more robust dynamical models.

  13. Radio-frequency discharges in oxygen: II. Spatio-temporally resolved optical emission pattern

    NASA Astrophysics Data System (ADS)

    Dittmann, K.; Drozdov, D.; Krames, B.; Meichsner, J.

    2007-11-01

    Axially and temporally resolved optical emission structures were investigated in the rf sheath region of a parallel plate capacitively coupled rf discharge (13.56 MHz) in pure oxygen and tetrafluoromethane. The rf discharge was driven at total pressures of between 10 and 100 Pa, gas flow rate of 3 sccm and rf power in the range 5-100 W. In particular, the emission of the atomic oxygen at 844.6 nm (3p3P ? 3s3S0) and the atomic carbon at 193 nm (3s1P0 ? 2p1D) were imaged with a lens onto the entrance slit of a spectrometer and detected by a fast ICCD-camera. The spatio-temporally resolved analysis of the emission intensity during the rf cycle (73.75 ns) provides two significant excitation processes inside the rf sheath: the electron impact excitation at the sheath edge, and heavy particle impact excitation in front of the powered electrode. In oxygen plasma the emission of atomic oxygen was found in both regions whereas in tetrafluoromethane the emission of atomic carbon was observed only in front of the powered electrode. The experimental results reveal characteristic dependence of the emission pattern in front of the powered electrode on plasma process parameters (self-bias voltage, pressure) and allow an estimation of the excitation threshold energy and effective cross section of energetic heavy particle loss.

  14. Within-day temporal patterns of smoking, withdrawal symptoms, and craving.

    PubMed

    Chandra, Siddharth; Scharf, Deborah; Shiffman, Saul

    2011-09-01

    We examined the temporal relationships between smoking frequency and craving and withdrawal. 351 heavy smokers (?15 cigarettes per day) used ecological momentary assessment and electronic diaries to track smoking, craving, negative affect, arousal, restlessness, and attention disturbance in real time over 16 days. The waking day was divided into 8 2-h "bins" during which cigarette counts and mean levels of craving and withdrawal were computed. Cross-sectional analyses showed no association between restlessness and smoking, and arousal and smoking, but craving (b=0.65, p<0.01) was positively associated, and negative affect (b=-0.20, p<0.01), and attention disturbance (b=-0.24, p<0.01) were inversely associated with smoking. In prospective lagged analyses, higher craving predicted more subsequent smoking and higher smoking predicted lower craving (p's<0.01). Higher restlessness also predicted more subsequent smoking and higher smoking predicted lower restlessness (p's<0.01). Higher negative affect did not predict later smoking, but more smoking preceded lower negative affect (p<0.01). Neither attention disturbance nor arousal predicted, or were predicted by variations in smoking. In short, smoking exhibits time-lagged, reciprocal relationships with craving and restlessness, and a one-way predictive relationship with negative affect. Temporal patterns of craving and restlessness may aid in the design of smoking cessation interventions. PMID:21324611

  15. Spatial and temporal electroselection patterns in electric field stimulation of polarized luminescence from photosynthetic membrane vesicles

    PubMed Central

    Rosemberg, Yosef; Rozen, Philip; Malkin, Shmuel; Korenstein, Rafi

    1992-01-01

    Electroselection processes of charge recombination are manifested in the study of electric field induced polarized emission from photosynthetic membrane vesicles. The study explores the coupled spatial-temporal characteristics of electric field induced charge recombination by examining the dependence of the integrated polarized emission and the time dependent polarization on electric field strength. The experimental results were fitted to theoretical models by computer simulations employing empirical parameters. Simulation of the dependence of the integrated polarized components of emission on electric field strength, suggests field-dependent increased ratio between radiative and nonradiative rates of charge recombination. The observation that the initial polarization values are independent of electric field strength supports the assumption that electric field induced emission originates from the pole area and then spreads away from it towards the equator. The propagation rate of this electric field induced charge recombination from the pole area towards the equator is reflected by the decay of polarization which increases upon raising the electric field strength. Simulation of the polarization's decay, based on a calculated angle of 26.3 ± 0.4° between the transition moment of emission and the plane of the membrane, establishes coupled temporal spatial patterns of electroselection in intramembrane electron transfer invoked by exposing preilluminated photosynthetic vesicles to a homogeneous electric field. PMID:19431835

  16. Modeling self-organized spatio-temporal patterns of PIP? and PTEN during spontaneous cell polarization.

    PubMed

    Knoch, Fabian; Tarantola, Marco; Bodenschatz, Eberhard; Rappel, Wouter-Jan

    2014-08-01

    During spontaneous cell polarization of Dictyostelium discoideum cells, phosphatidylinositol (3,4,5)-triphoshpate (PIP3) and PTEN (phosphatase tensin homolog) have been identified as key signaling molecules which govern the process of polarization in a self-organized manner. Recent experiments have quantified the spatio-temporal dynamics of these signaling components. Surprisingly, it was found that membrane-bound PTEN can be either in a high or low state, that PIP3 waves were initiated in areas lacking PTEN through an excitable mechanism, and that PIP3 was degraded even though the PTEN concentration remained low. Here we develop a reaction-diffusion model that aims to explain these experimental findings. Our model contains bistable dynamics for PTEN, excitable dynamics for PIP3, and postulates the existence of two species of PTEN with different dephosphorylation rates. We show that our model is able to produce results that are in good qualitative agreement with the experiments, suggesting that our reaction-diffusion model underlies the self-organized spatio-temporal patterns observed in experiments. PMID:25024302

  17. Within-Day Temporal Patterns of Smoking, Withdrawal Symptoms, and Craving*

    PubMed Central

    Chandra, Siddharth; Scharf, Deborah; Shiffman, Saul

    2011-01-01

    We examined the temporal relationships between smoking frequency and craving and withdrawal. 351 heavy smokers (?15 cigarettes per day) used ecological momentary assessment and electronic diaries to track smoking, craving, negative affect, arousal, restlessness, and attention disturbance in real time over 16 days. The waking day was divided into 8 2-hour “bins” during which cigarette counts and mean levels of craving and withdrawal were computed. Cross-sectional analyses showed no association between restlessness and smoking, and arousal and smoking, but craving (b=0.65, p<0.01) was positively associated, and negative affect (b=-0.20, p<0.01), and attention disturbance (b=-0.24, p<0.01) were inversely associated with smoking. In prospective lagged analyses, higher craving predicted more subsequent smoking and higher smoking predicted lower craving (p's < 0.01). Higher restlessness also predicted more subsequent smoking and higher smoking predicted lower restlessness (p's < 0.01). Higher negative affect did not predict later smoking, but more smoking preceded lower negative affect (p<0.01). Neither attention disturbance nor arousal predicted, or were predicted by variations in smoking. In short, smoking exhibits time-lagged, reciprocal relationships with craving and restlessness, and a one-way predictive relationship with negative affect. Temporal patterns of craving and restlessness may aid in the design of smoking cessation interventions. PMID:21324611

  18. The importance of the temporal pattern of syllables and the syllable structure of display calls for individual recognition in the genus aptenodytes.

    PubMed

    Robisson, P

    1991-01-01

    Aptenodytes penguins have a recognition call consisting of a series of repeated syllables. Play-back experiments were conducted to determine the respective importance of the temporal pattern of syllables and the syllable structure. Two hybrid signals were created by switching the temporal pattern of the familiar call (partner or parent) with that of an alien call, then played back to relevant partners. The hybrid signal with the familiar temporal pattern of syllables and an alien syllable structure induced no response of individual recognition, while the hybrid signal with an alien temporal pattern of syllables and the familiar syllable structure elicited some positive responses. PMID:24897176

  19. Electrophysiological evidence for a defect in the processing of temporal sound patterns in multiple sclerosis

    PubMed Central

    Jones, S; Sprague, L; Vaz, P

    2002-01-01

    Objectives: To assess the processing of spectrotemporal sound patterns in multiple sclerosis by using auditory evoked potentials (AEPs) to complex harmonic tones. Methods: 22 patients with definite multiple sclerosis but mild disability and no auditory complaints were compared with 15 normal controls. Short latency AEPs were recorded using standard methods. Long latency AEPs were recorded to synthesised musical instrument tones, at onset every two seconds, at abrupt frequency changes every two seconds, and at the end of a two second period of 16/s frequency changes. The subjects were inattentive but awake, reading irrelevant material. Results: Short latency AEPs were abnormal in only 4 of 22 patients, whereas long latency AEPs were abnormal to one or more stimuli in 17 of 22. No significant latency prolongation was seen in response to onset and infrequent frequency changes (P1, N1, P2) but the potentials at the end of 16/s frequency modulations, particularly the P2 peaking approximately 200 ms after the next expected change, were significantly delayed. Conclusion: The delayed responses appear to be a mild disorder in the processing of change in temporal sound patterns. The delay may be conceived of as extra time taken to compare the incoming sound with the contents of a temporally ordered sensory memory store (the long auditory store or echoic memory), which generates a response when the next expected frequency change fails to occur. The defect cannot be ascribed to lesions of the afferent pathways and so may be due to disseminated brain lesions visible or invisible on magnetic resonance imaging. PMID:12397152

  20. Temporal patterns in appearance of sooty blotch and flyspeck fungi on apples.

    PubMed

    Batzer, J C; Sisson, A J; Harrington, T C; Mayfield, D A; Gleason, M L

    2012-11-01

    Sooty blotch and flyspeck (SBFS) is a complex of about 80 fungal species that blemish the surface of apple fruit in humid regions worldwide. The dark colonies become visible in mid- to late summer, reducing the value of fresh fruit. Although many SBFS species can co-occur in the same orchard and even on the same apple, little is known about temporal patterns of these species, including the timing of colony appearance. To test the hypothesis that colonies of SBFS species appear on apples at characteristic times during the growing season, 50 apples were monitored weekly at three Iowa orchards in 2006 and six orchards in 2007 and 2008. However, a mean of 24.3 apples per orchard was assessed at harvest because of apple drop throughout the season. Colonies were marked with colored pens as they appeared. After harvest and after storage of apples at 2 °C for 3 months, SBFS colonies on each fruit were counted and classified by morphology, and a representative subset of colonies was excised from the fruit and preserved on dried peels for species identification using rDNA. Seventeen species were identified. Stomiopeltis spp. RS1 and RS2 appeared on apples 10 to 14 days before other SBFS taxa. Dissoconium aciculare was generally the last species to appear on apple fruit, and it continued to appear during postharvest storage. The most prevalent taxa in Iowa orchards were also the most abundant. Diversity of SBFS fungi in an orchard was positively correlated with cumulative hours of surface wetness hours due to rainfall or dew, which is believed to favor growth of SBFS fungi. Species-specific information about temporal patterns of appearance on apple fruit may lead to improved SBFS management strategies. PMID:22832919

  1. Spatial and temporal statistical analysis of bycatch data: Patterns of sea turtle bycatch in the North Atlantic

    USGS Publications Warehouse

    Gardner, B.; Sullivan, P.J.; Morreale, S.J.; Epperly, S.P.

    2008-01-01

    Loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtle distributions and movements in offshore waters of the western North Atlantic are not well understood despite continued efforts to monitor, survey, and observe them. Loggerhead and leatherback sea turtles are listed as endangered by the World Conservation Union, and thus anthropogenic mortality of these species, including fishing, is of elevated interest. This study quantifies spatial and temporal patterns of sea turtle bycatch distributions to identify potential processes influencing their locations. A Ripley's K function analysis was employed on the NOAA Fisheries Atlantic Pelagic Longline Observer Program data to determine spatial, temporal, and spatio-temporal patterns of sea turtle bycatch distributions within the pattern of the pelagic fishery distribution. Results indicate that loggerhead and leatherback sea turtle catch distributions change seasonally, with patterns of spatial clustering appearing from July through October. The results from the space-time analysis indicate that sea turtle catch distributions are related on a relatively fine scale (30-200 km and 1-5 days). The use of spatial and temporal point pattern analysis, particularly K function analysis, is a novel way to examine bycatch data and can be used to inform fishing practices such that fishing could still occur while minimizing sea turtle bycatch. ?? 2008 NRC.

  2. Spatial and temporal patterns of large-scale droughts in Europe: model dispersion and performance

    NASA Astrophysics Data System (ADS)

    Tallaksen, Lena M.; Stahl, Kerstin

    2014-05-01

    Droughts are regional events that have a wide range of environmental and socio-economic impacts and thus, it is vital that models correctly simulate drought characteristics in a future climate. In this study we explore the performance of a suite of off-line, global hydrological and land surface models in mapping spatial and temporal patterns of large-scale hydrological droughts. The model ensemble consists of seven global models run with the same simulation setup (developed in a joint effort within the WATCH project). Daily total runoff (sum of fast and slow component) simulated for each grid cell in Europe for the period 1963-2000 constitute the basis for the analysis. Simulated and observed daily (7-day backward-smoothed) runoff series for each grid cell were first transformed into nonparametric anomalies, and a grid cell is considered to be in drought if the runoff is below q20, i.e., the 20% non-exceedance frequency of that day. The mean annual drought area, i.e., the average of the daily total area in drought, is used to characterize the overall dryness of a year. The annual maximum drought cluster area, i.e., the area of the largest cluster of spatially contiguous cells in drought within a year, is chosen as a measure of the severity of a given drought. The total number of drought events is defined as runs of consecutive days in drought over the entire record. Consistent model behavior was found for inter-annual variability in mean drought area, whereas high model dispersion was revealed in the weekly evolution of contiguous area in drought and its annual maximum. Comparison with nearly three hundred catchment-scale streamflow observations showed an overall tendency to overestimate the number of drought events and hence, underestimate drought duration, whereas persistence in drought affected area (weekly mean) was underestimated, noticeable for one group of models. The high model dispersion in temporal and spatial persistence of drought identified implies that care should be taken when analyzing drought characteristics from only one or a limited number of models unless validated specifically for hydrological drought. Citation: Tallaksen, L.M., Stahl, K. (2014) Spatial and temporal patterns of large-scale droughts in Europe: model dispersion and performance. Geophysical Research Letters (accepted), doi: 10.1002/2013GL058573

  3. Spatial and Temporal Patterns of Biocide Action against Staphylococcus epidermidis Biofilms? ‡

    PubMed Central

    Davison, William M.; Pitts, Betsey; Stewart, Philip S.

    2010-01-01

    The dynamic antimicrobial action of chlorine, a quaternary ammonium compound, glutaraldehyde, and nisin within biofilm cell clusters of Staphylococcus epidermidis was investigated using time-lapse confocal scanning laser microscopy. The technique allowed for the simultaneous imaging of changes in biofilm structure and disruption of cellular membrane integrity through the loss of an unbound fluorophore loaded into bacterial cells prior to antimicrobial challenge. Each of the four antimicrobial agents produced distinct spatial and temporal patterns of fluorescence loss. The antimicrobial action of chlorine was localized around the periphery of biofilm cell clusters. Chlorine was the only antimicrobial agent that caused any biofilm removal. Treatment with the quaternary ammonium compound caused membrane permeabilization that started at the periphery of cell clusters, then migrated steadily inward. A secondary pattern superimposed on the penetration dynamic suggested a subpopulation of less-susceptible cells. These bacteria lost fluorescence much more slowly than the majority of the population. Nisin caused a rapid and uniform loss of green fluorescence from all parts of the biofilm without any removal of biofilm. Glutaraldehyde caused no biofilm removal and also no loss of membrane integrity. Measurements of biocide penetration and action time at the center of cell clusters yielded 46 min for 10 mg liter?1 chlorine, 21 min for 50 mg liter?1 chlorine, 25 min for the quaternary ammonium compound, and 4 min for nisin. These results underscore the distinction between biofilm removal and killing and reinforce the critical role of biocide reactivity in determining the rate of biofilm penetration. PMID:20457816

  4. Spatial and temporal patterns of micropollutants upstream and downstream of 24 WWTPs across Switzerland

    NASA Astrophysics Data System (ADS)

    Spycher, Barbara; Deuber, Fabian; Kistler, David; Burdon, Frank; Reyes, Marta; Alder, Alfredo C.; Joss, Adriano; Eggen, Rik; Singer, Heinz; Stamm, Christian

    2015-04-01

    Treated wastewater is an important source of micropollutants in many streams. These chemicals consist of very diverse set of compounds that may vary in space and time. In order to improve our understanding of such spatio-temporal patterns of micropollutants in surface waters, we compared upstream and downstream locations at 24 sites across the Swiss Plateau and Jura (12 sites in the 2013 campaign, 12 sites during the 2014 campaign). Each site represents the most upstream treatment plant in the corresponding catchment. This survey is part of the interdisciplinary, Eawag-wide research project EcoImpact that aims at elucidating the ecological effects of micropollutants on stream ecosystems. In 2013, a broad analytical screening was applied to samples collected during winter (January) and summer conditions (June). Based in these results, the bi-monthly samples obtained in 2014 were analysed for a set of about 60 selected organic micropollutants and 10 heavy metals. The screening results demonstrate that generally pharmaceuticals, artificial sweeteners and corrosion inhibitors make up the largest part of the organic micropollutants. Pesticides including biocides and plant protection products are also regularly found but at lower concentrations. This presentation will analyse the variability of the micropollutant patterns across the different sites and how upstream conditions and the wastewater composition changes with season.

  5. Does Sex Matter? Temporal and Spatial Patterns of Cougar-Human Conflict in British Columbia

    PubMed Central

    Teichman, Kristine J.; Cristescu, Bogdan; Nielsen, Scott E.

    2013-01-01

    Wildlife-human conflicts occur wherever large carnivores overlap human inhabited areas. Conflict mitigation can be facilitated by understanding long-term dynamics and examining sex-structured conflict patterns. Predicting areas with high probability of conflict helps focus management strategies in order to proactively decrease carnivore mortality. We investigated the importance of cougar (Puma concolor) habitat, human landscape characteristics and the combination of habitat and human features on the temporal and spatial patterns of cougar-human conflicts in British Columbia. Conflicts (n?=?1,727; 1978–2007) involved similar numbers of male and female cougars with conflict rate decreasing over the past decade. Conflicts were concentrated within the southern part of the province with the most conflicts per unit area occurring on Vancouver Island. For both sexes, the most supported spatial models for the most recent (1998–2007) conflicts contained both human and habitat variables. Conflicts were more likely to occur close to roads, at intermediate elevations and far from the northern edge of the cougar distribution range in British Columbia. Male cougar conflicts were more likely to occur in areas of intermediate human density. Unlike cougar conflicts in other regions, cattle density was not a significant predictor of conflict location. With human populations expanding, conflicts are expected to increase. Conservation tools, such as the maps predicting conflict hotspots from this study, can help focus management efforts to decrease carnivore-human conflict. PMID:24040312

  6. Behavioral and physiological correlates of temporal pitch perception in electric and acoustic hearing

    PubMed Central

    Carlyon, Robert P.; Mahendran, Suresh; Deeks, John M.; Long, Christopher J.; Axon, Patrick; Baguley, David; Bleeck, Stefan; Winter, Ian M.

    2008-01-01

    In the “4-6” condition of experiment 1, normal-hearing (NH) listeners compared the pitch of a bandpass-filtered pulse train, whose inter-pulse intervals (IPIs) alternated between 4 and 6 ms, to that of isochronous pulse trains. Consistent with previous results obtained at a lower signal level, the pitch of the 4-6 stimulus corresponded to that of an isochronous pulse train having a period of 5.7 ms – longer than the mean IPI of 5 ms. In other conditions the IPI alternated between 3.5-5.5 ms and 4.5-6.5 ms. Experiment 2 was similar but presented electric pulse trains to one channel of a CI. In both cases, as overall IPI increased, the pitch of the alternating-interval stimulus approached that of an isochronous train having a period equal to the mean IPI. Experiment 3 measured compound action potentials (CAPs) to alternating-interval stimuli in guinea pigs and in NH listeners. The CAPs to pulses occurring after 4-ms intervals were smaller than responses to pulses occurring after 6-ms intervals, resulting in a modulated pattern that was independent of overall level. The results are compared to the predictions of a simple model incorporating auditory-nerve (AN) refractoriness, and where pitch is estimated from 1st-order intervals in the AN response. PMID:18247900

  7. THE ACOUSTICS OF A LARGE SPACE WITH A REPETITIVE PATTERN OF COUPLED ROOMS

    Microsoft Academic Search

    J. S. Anderson; M. Bratos-Anderson; P. Doany

    1997-01-01

    The acoustics are discussed of a large building divided by arches and columns into 77 coupled “subspaces” or rooms. Two models of coupled rooms have been devised to predict acoustical characteristics such as the decay of sound energy density and reverberation time. The first is a general model which can be supplied to any system of coupled rooms. For each

  8. Temporal scales and patterns of invertebrate biodiversity dynamics in boreal lakes recovering from acidification.

    PubMed

    Angeler, David G; Johnson, Richard K

    2012-06-01

    Despite international policy implementation to reduce atmospheric acid deposition and restore natural resources from cultural acidification, evidence of ecological recovery is equivocal. Failure to meet recovery goals means that acidification still threatens biodiversity in many areas of the world. Managers thus need information to manage biodiversity, especially its components that are sensitive to stress (acid-sensitive taxa). We analyzed 20-year time series (1988-2007) of water quality and littoral invertebrates in acidified and circum-neutral lakes across Sweden to evaluate regional biodiversity dynamics and the extent to which changes in water quality affect these dynamics. We used multivariate time series modeling to (1) test how individual species groups within invertebrate communities track changes in the abiotic environment and (2) reveal congruencies of taxon contributions to species group change across lakes. Chemical recovery in the lakes was equivocal, and increases of pH and alkalinity were observed in subsets of acidified and circum-neutral lakes. Time series analyses revealed two different patterns of species groups for invertebrate communities across lakes; the first species group showed monotonic change over time, while the second group showed fluctuating temporal patterns. These independent species groups correlated distinctly with different sets of environmental variables. Recovery of pH and alkalinity status was associated with species group patterns only in a few lakes, highlighting an overall weak recovery of invertebrate species. The sets of species, including acid-sensitive taxa, composing these species groups differed markedly across lakes, highlighting context-specific responses of invertebrates to environmental variation. These results are encouraging because disparate local-scale dynamics maintain the diversity of sensitive invertebrate species on a regional scale, despite persisting acidification problems. Our study can inform and help refine current acidification-related policy focused on sensitive biodiversity elements. PMID:22827126

  9. Analysis of spatio-temporal brain imaging patterns by Hidden Markov Models and serial MRI images.

    PubMed

    Wang, Ying; Resnick, Susan M; Davatzikos, Christos

    2014-09-01

    Brain changes due to development and maturation, normal aging, or degenerative disease are continuous, gradual, and variable across individuals. To quantify the individual progression of brain changes, we propose a spatio-temporal methodology based on Hidden Markov Models (HMM), and apply it on four-dimensional structural brain magnetic resonance imaging series of older individuals. First, regional brain features are extracted in order to reduce image dimensionality. This process is guided by the objective of the study or the specific imaging patterns whose progression is of interest, for example, the evaluation of Alzheimer-like patterns of brain change in normal individuals. These regional features are used in conjunction with HMMs, which aim to measure the dynamic association between brain structure changes and progressive stages of disease over time. A bagging framework is used to obtain models with good generalization capability, since in practice the number of serial scans is limited. An application of the proposed methodology was to detect individuals with the risk of developing MCI, and therefore it was tested on modeling the progression of brain atrophy patterns in older adults. With HMM models, the state-transition paths corresponding to longitudinal brain changes were constructed from two completely independent datasets, the Alzheimer Disease Neuroimaging Initiative and the Baltimore Longitudinal Study of Aging. The statistical analysis of HMM-state paths among the normal, progressive MCI, and MCI groups indicates that, HMM-state index 1 is likely to be a predictor of the conversion from cognitively normal to MCI, potentially many years before clinical symptoms become measurable. PMID:24706564

  10. Temporal patterns in daily measurements of inorganic and organic speciated PM2.5 in Denver

    PubMed Central

    Dutton, Steven J.; Rajagopalan, Balaji; Vedal, Sverre; Hannigan, Michael P.

    2013-01-01

    Airborne particulate matter less than 2.5 ?m in aerodynamic diameter (PM2.5) has been linked to a wide range of adverse health effects and as a result is currently regulated by the U.S. Environmental Protection Agency. PM2.5 originates from a multitude of sources and has heterogeneous physical and chemical characteristics. These features complicate the link between PM2.5 emission sources, ambient concentrations and health effects. The goal of the Denver Aerosol Sources and Health (DASH) study is to investigate associations between sources and health using daily measurements of speciated PM2.5 in Denver. The datxa set being collected for the DASH study will be the longest daily speciated PM2.5 data set of its kind covering 5.5 years of daily inorganic and organic speciated measurements. As of 2008, 4.5 years of bulk measurements (mass, inorganic ions and total carbon) and 1.5 years of organic molecular marker measurements have been completed. Several techniques were used to reveal long-term and short-term temporal patterns in the bulk species and the organic molecular marker species. All species showed a strong annual periodicity, but their monthly and seasonal behavior varied substantially. Weekly periodicities appear in many compound classes with the most significant weekday/weekend effect observed for elemental carbon, cholestanes, hopanes, select polycyclic aromatic hydrocarbons (PAHs), heavy n-alkanoic acids and methoxyphenols. Many of the observed patterns can be explained by meteorology or anthropogenic activity patterns while others do not appear to have such obvious explanations. Similarities and differences in these findings compared to those reported from other cities are highlighted. PMID:23486844

  11. Understanding flood-induced water chemistry variability extracting temporal patterns with the LDA method

    NASA Astrophysics Data System (ADS)

    Aubert, A. H.; Tavenard, R.; Emonet, R.; De Lavenne, A.; Malinowski, S.; Guyet, T.; Quiniou, R.; Odobez, J.; Merot, P.; Gascuel-odoux, C.

    2013-12-01

    Studying floods has been a major issue in hydrological research for years, both in quantitative and qualitative hydrology. Stream chemistry is a mix of solutes, often used as tracers, as they originate from various sources in the catchment and reach the stream by various flow pathways. Previous studies (for instance (1)) hypothesized that stream chemistry reaction to a rainfall event is not unique but varies seasonally, and according to the yearly meteorological conditions. Identifying a typology of flood temporal chemical patterns is a way to better understand catchment processes at the flood and seasonal time scale. We applied a probabilistic model (Latent Dirichlet Allocation or LDA (2)) mining recurrent sequential patterns from a dataset of floods. A set of 472 floods was automatically extracted from a daily 12-year long record of nitrate, dissolved organic carbon, sulfate and chloride concentrations. Rainfall, discharge, water table depth and temperature are also considered. Data comes from a long-term hydrological observatory (AgrHys, western France) located at Kervidy-Naizin. From each flood, a document has been generated that is made of a set of "hydrological words". Each hydrological word corresponds to a measurement: it is a triplet made of the considered variable, the time at which the measurement is made (relative to the beginning of the flood), and its magnitude (that can be low, medium or high). The documents and the number of pattern to be mined are used as input data to the LDA algorithm. LDA relies on spotting co-occurrences (as an alternative to the more traditional study of correlation) between words that appear within the flood documents. It has two nice properties that are its ability to easily deal with missing data and its additive property that allows a document to be seen as a mixture of several flood patterns. The output of LDA is a set of patterns easily represented in graphics. These patterns correspond to typical reactions to rainfall events. The patterns themselves are carefully studied, as well as their repartition along the year and along the 12 years of the dataset. We would recommend the use of such model to any study based on patterns or signature extraction. It could be well suited to compare different geographical locations and analyzing the resulting different pattern distributions. (1) Aubert, A.H., Gascuel-Odoux, C., Gruau, G., Akkal, N., Faucheux, M., Fauvel, Y., Grimaldi, C., Hamon, Y., Jaffrezic, A., Lecoz Boutnik, M., Molenat, J., Petitjean, P., Ruiz, L., Merot, Ph. (2013), Solute transport dynamics in small, shallow groundwater-dominated agricultural catchments: insights from a high-frequency, multisolute 10 yr-long monitoring study. Hydrol. Earth Syst. Sci., 17(4): 1379-1391. (2) Aubert, A.H., Tavenard, R, Emonet, R., de Lavenne, A., Malinowski, S., Guyet, T., Quiniou, R., Odobez, J.-M., Merot, Ph., Gascuel-Odoux, C., submitted to WRR. Clustering with a probabilistic method newly applied in hydrology: application on flood events from water quality time-series.

  12. Rapid Generation of Multiplexed Cell Cocultures Using Acoustic Droplet Ejection Followed by Aqueous Two-Phase Exclusion Patterning

    PubMed Central

    Fang, Yu; Frampton, John P.; Raghavan, Shreya; Sabahi-Kaviani, Rahman; Luker, Gary

    2012-01-01

    The development of tools for patterning cocultures of cells is a fundamental interest among cell biologists and tissue engineers. Although a variety of systems exist for micropatterning cells, the methods used to generate cell micropatterns are often cumbersome and difficult to adapt for tissue engineering purposes. This study combines acoustic droplet ejection and aqueous two-phase system exclusion patterning to introduce a method for patterning cocultures of cells in multiplexed arrays. This new method uses focused acoustic radiation pressure to eject discrete droplets of uniform size from the surface of a dextran solution containing cells. The size of droplets is controlled by adjusting ultrasound parameters, such as pulse, duration, and amplitude. The ejected dextran droplets are captured on a cell culture substrate that is manipulated by a computer-controlled 3D positioning system according to predesigned patterns. Polyethylene glycol solution containing an additional cell type is then added to the culture dish to produce a two-phase system capable of depositing different types of cells around the initial pattern of cells. We demonstrate that our method can produce patterns of islands or lines with two or more cell types. Further, we demonstrate that patterns can be multiplexed for studies involving combinations of multiple cell types. This method offers a tool to transfer cell-containing samples in a contact-free, nozzle-less manner, avoiding sample cross-contamination. It can be used to pattern cell cocultures without complicated fabrication of culture substrates. These capabilities were used to examine the response of cancer cells to the presence of a ligand (CXCL12) secreted from surrounding cocultured cells. PMID:22356298

  13. Factors influencing the temporal and spatial patterns of dogwood borer (Lepidoptera: Sesiidae) infestations in newly planted apple orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The temporal and spatial patterns of infestation by larval dogwood borer, Synanthedon scitula (Harris), was studied during 2002–2004 in two newly planted apple orchards in West Virginia and Virginia. The orchards contained several rootstock-variety combinations grown under different cultural manage...

  14. Water quality in the Fort Cobb Watershed, USA: Spatial and temporal patterns of dissolved P stream concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dissolved phosphorus (P) has often been identified as the nutrient of concern in lakes, reservoirs and streams especially where there is evidence of eutrophication. The objective of this work is to identify spatial and temporal patterns in dissolved P [soluble reactive P (SRP) and bioavailable P (B...

  15. Floating and fixed artificial habitats: Spatial and temporal patterns of benthic communities in a coral reef environment

    E-print Network

    Benayahu, Yehuda

    Floating and fixed artificial habitats: Spatial and temporal patterns of benthic communities of the effect of motion on the communities of floating artificial habitats such as buoys, rafts, and pontoons, particularly in tropical systems. Hydrodynamic features greatly differ between floating and fixed artificial

  16. EPIDEMIOLOGY OF CHRONIC WASTING DISEASE IN FREE RANGING MULE DEER: SPATIAL, TEMPORAL, AND DEMOGRAPHIC INFLUENCES ON OBSERVED PREVALENCE PATTERNS

    Microsoft Academic Search

    Michael W. Miller; Mary M. Conner

    2005-01-01

    We analyzed chronic wasting disease (CWD) prevalence data from mule deer pop- ulations in northcentral Colorado, USA, to discern the likely influences of temporal, spatial, and demographic factors on patterns observed in naturally infected populations. In addition to reaf- firming spatial heterogeneity among wintering mule deer subpopulations, we report marked dif- ferences in CWD prevalence by sex and age groups

  17. DATA-DRIVEN DISCOVERY OF TEMPORAL AND GEOSPATIAL PATTERNS OF DISEASE TRANSMISSION: WEST NILE VIRUS IN MARYLAND

    EPA Science Inventory

    The necessity of rapid response to a developing disease outbreak often precludes systematic investigation of the mechanisms and patterns (temporal and geospatial) of spread. In order to deploy the most rapid response possible, we must exploit existing data to its maximum extent....

  18. Temporally patterned pulse trains affect directional sensitivity of inferior collicular neurons of the big brown bat, Eptesicus fuscus

    Microsoft Academic Search

    M. I. Wu; P. H. S. Jen

    1996-01-01

    The directional sensitivity of inferior collicular neurons of the big brown bat, Eptesicus fuscus, was studied under free field stimulation conditions with 3 temporally patterned trains of sound pulses which differed in pulse repetition rate and duration. The directional sensitivity curves of 92 neurons studied can be described as hemifield, directionally-selective, or non-directional according to the variation in the number

  19. A Pattern Mining Approach for Classifying Multivariate Temporal Data Iyad Batal, Hamed Valizadegan, Gregory F. Cooper and Milos Hauskrecht

    E-print Network

    Hauskrecht, Milos

    -world clinical task of predicting patients who are at risk of developing heparin induced thrombocytopenia is one of the most challenging topics of data mining research. This work primarily focuses on developing to define complex temporal patterns like "the administration of heparin precedes a decreasing trend

  20. Spatial and temporal variation in mortality of newly settled damselfish: patterns, causes and co-variation with settlement

    Microsoft Academic Search

    Sally J. Holbrook; Russell J. Schmitt

    2003-01-01

    Local abundance and dynamics of sedentary species with a dispersing life stage reflect factors that influence input and loss rates to patches of suitable habitat. For reef fishes, more attention has focused on sources of variation in input (larval settlement) than on patterns and causes of subsequent losses. We estimated spatial and temporal variation in juvenile mortality of a tropical

  1. When to feed on gums: Temporal patterns of gummivory in wild tamarins,Saguinus mystaxand Saguinus fuscicollis(Callitrichinae)

    Microsoft Academic Search

    Eckhard W. Heymann; Andrew C. Smith

    1999-01-01

    This study examines the temporal patterning of gum feeding in two species of sympatric tamarin monkeys, Saguinus mystax and Saguinus fuscicollis, during the diurnal activity period. The number and duration of visits to gum sources and number of gum feeding records are used as parameters to analyze the gum feeding itinerary. Both visits to gum sources and gum feeding records

  2. Buoyancy characteristics of the bloater (Coregonus hoyi) in relation to patterns of vertical migration and acoustic backscattering

    USGS Publications Warehouse

    Fleischer, Guy W.; TeWinkel, Leslie M.

    1998-01-01

    Acoustic studies in Lake Michigan found that bloaters (Coregonus hoyi) were less reflective per size than the other major pelagic species. This difference in in situ acoustic backscattering could indicate that the deep-water bloaters have compressed swimbladders for much of their vertical range with related implications on buoyancy. To test this hypothesis, the buoyancy characteristics of bloaters were determined with fish placed in a cage that was lowered to bottom and monitored with an underwater camera. We found bloaters were positively buoyant near surface, neutrally buoyant at intermediate strata, and negatively buoyant near bottom. This pattern was consistent for the range of depths bloaters occur. The depth of neutral buoyancy (near the 50-n strata) corresponds with the maximum extent of vertical migration for bloaters observed in acoustic surveys. Fish below this depth would be negatively buoyant which supports our contention that bloaters deeper in the water column have compressed swimbladders. Understanding the buoyancy characteristics of pelagic fishes will help to predict the effects of vertical migration on target strength measurement and confirms the use of acoustics as a tool to identify and quantify the ecological phenomenon of vertical migration.

  3. Temporal patterns of nitrogenase gene (nifH) expression in the oligotrophic North Pacific Ocean.

    PubMed

    Church, Matthew J; Short, Cindy M; Jenkins, Bethany D; Karl, David M; Zehr, Jonathan P

    2005-09-01

    Dinitrogen (N(2))-fixing microorganisms (diazotrophs) play important roles in ocean biogeochemistry and plankton productivity. In this study, we examined the presence and expression of specific planktonic nitrogenase genes (nifH) in the upper ocean (0 to 175 m) at Station ALOHA in the oligotrophic North Pacific Ocean. Clone libraries constructed from reverse-transcribed PCR-amplified mRNA revealed six unique phylotypes. Five of the nifH phylotypes grouped with sequences from unicellular and filamentous cyanobacteria, and one of the phylotypes clustered with gamma-proteobacteria. The cyanobacterial nifH phylotypes retrieved included two sequence types that phylogenetically grouped with unicellular cyanobacteria (termed groups A and B), several sequences closely related (97 to 99%) to Trichodesmium spp. and Katagnymene spiralis, and two previously unreported phylotypes clustering with heterocyst-forming nifH cyanobacteria. Temporal patterns of nifH expression were evaluated using reverse-transcribed quantitative PCR amplification of nifH gene transcripts. The filamentous and presumed unicellular group A cyanobacterial phylotypes exhibited elevated nifH transcription during the day, while members of the group B (closely related to Crocosphaera watsonii) unicellular phylotype displayed greater nifH transcription at night. In situ nifH expression by all of the cyanobacterial phylotypes exhibited pronounced diel periodicity. The gamma-proteobacterial phylotype had low transcript abundance and did not exhibit a clear diurnal periodicity in nifH expression. The temporal separation of nifH expression by the various phylotypes suggests that open ocean diazotrophic cyanobacteria have unique in situ physiological responses to daily fluctuations of light in the upper ocean. PMID:16151126

  4. Spatial and temporal patterns of coexistence between competing Aedes mosquitoes in urban Florida.

    PubMed

    Leisnham, Paul T; Juliano, S A

    2009-05-01

    Understanding mechanisms fostering coexistence between invasive and resident species is important in predicting ecological, economic, or health impacts of invasive species. The mosquito Aedes aegypti coexists at some urban sites in southeastern United States with invasive Aedes albopictus, which is often superior in interspecific competition. We tested predictions for three hypotheses of species coexistence: seasonal condition-specific competition, aggregation among individual water-filled containers, and colonization-competition tradeoff across spatially partitioned habitat patches (cemeteries) that have high densities of containers. We measured spatial and temporal patterns of abundance for both species among water-filled resident cemetery vases and experimentally positioned standard cemetery vases and ovitraps in metropolitan Tampa, Florida. Consistent with the seasonal condition-specific competition hypothesis, abundances of both species in resident and standard cemetery vases were higher early in the wet season (June) versus late in the wet season (September), but the proportional increase of A. albopictus was greater than that of A. aegypti, presumably due to higher dry-season egg mortality and strong wet-season competitive superiority of larval A. albopictus. Spatial partitioning was not evident among cemeteries, a result inconsistent with the colonization-competition tradeoff hypothesis, but both species were highly independently aggregated among standard cemetery vases and ovitraps, which is consistent with the aggregation hypothesis. Densities of A. aegypti but not A. albopictus differed among land use categories, with A. aegypti more abundant in ovitraps in residential areas compared to industrial and commercial areas. Spatial partitioning among land use types probably results from effects of land use on conditions in both terrestrial and aquatic-container environments. These results suggest that both temporal and spatial variation may contribute to local coexistence between these Aedes in urban areas. PMID:19263086

  5. Interpreting the spatio-temporal patterns of sea turtle strandings: Going with the flow

    USGS Publications Warehouse

    Hart, K.M.; Mooreside, P.; Crowder, L.B.

    2006-01-01

    Knowledge of the spatial and temporal distribution of specific mortality sources is crucial for management of species that are vulnerable to human interactions. Beachcast carcasses represent an unknown fraction of at-sea mortalities. While a variety of physical (e.g., water temperature) and biological (e.g., decomposition) factors as well as the distribution of animals and their mortality sources likely affect the probability of carcass stranding, physical oceanography plays a major role in where and when carcasses strand. Here, we evaluate the influence of nearshore physical oceanographic and wind regimes on sea turtle strandings to decipher seasonal trends and make qualitative predictions about stranding patterns along oceanfront beaches. We use results from oceanic drift-bottle experiments to check our predictions and provide an upper limit on stranding proportions. We compare predicted current regimes from a 3D physical oceanographic model to spatial and temporal locations of both sea turtle carcass strandings and drift bottle landfalls. Drift bottle return rates suggest an upper limit for the proportion of sea turtle carcasses that strand (about 20%). In the South Atlantic Bight, seasonal development of along-shelf flow coincides with increased numbers of strandings of both turtles and drift bottles in late spring and early summer. The model also predicts net offshore flow of surface waters during winter - the season with the fewest relative strandings. The drift bottle data provide a reasonable upper bound on how likely carcasses are to reach land from points offshore and bound the general timeframe for stranding post-mortem (< two weeks). Our findings suggest that marine turtle strandings follow a seasonal regime predictable from physical oceanography and mimicked by drift bottle experiments. Managers can use these findings to reevaluate incidental strandings limits and fishery takes for both nearshore and offshore mortality sources. ?? 2005 Elsevier Ltd. All rights reserved.

  6. Temporal and Spatial Patterns of Ambient Endotoxin Concentrations in Fresno, California

    PubMed Central

    Tager, Ira B.; Lurmann, Frederick W.; Haight, Thaddeus; Alcorn, Siana; Penfold, Bryan; Hammond, S. Katharine

    2010-01-01

    Background Endotoxins are found in indoor dust generated by human activity and pets, in soil, and adsorbed onto the surfaces of ambient combustion particles. Endotoxin concentrations have been associated with respiratory symptoms and the risk of atopy and asthma in children. Objective We characterized the temporal and spatial variability of ambient endotoxin in Fresno/Clovis, California, located in California’s Central Valley, to identify correlates and potential predictors of ambient endotoxin concentrations in a cohort of children with asthma [Fresno Asthmatic Children’s Environment Study (FACES)]. Methods Between May 2001 and October 2004, daily ambient endotoxin and air pollutants were collected at the central ambient monitoring site of the California Air Resources Board in Fresno and, for shorter time periods, at 10 schools and indoors and outdoors at 84 residences in the community. Analyses were restricted to May–October, the dry months during which endotoxin concentrations are highest. Results Daily endotoxin concentration patterns were determined mainly by meteorologic factors, particularly the degree of air stagnation. Overall concentrations were lowest in areas distant from agricultural activities. Highest concentrations were found in areas immediately downwind from agricultural/pasture land. Among three other measured air pollutants [fine particulate matter, elemental carbon (a marker of traffic in Fresno), and coarse particulate matter (PMc)], PMc was the only pollutant correlated with endotoxin. Endotoxin, however, was the most spatially variable. Conclusions Our data support the need to evaluate the spatial/temporal variability of endotoxin concentrations, rather than relying on a few measurements made at one location, in studies of exposure and and respiratory health effects, particularly in children with asthma and other chronic respiratory diseases. PMID:20494854

  7. Temporal Patterns of Nitrogenase Gene (nifH) Expression in the Oligotrophic North Pacific Ocean

    PubMed Central

    Church, Matthew J.; Short, Cindy M.; Jenkins, Bethany D.; Karl, David M.; Zehr, Jonathan P.

    2005-01-01

    Dinitrogen (N2)-fixing microorganisms (diazotrophs) play important roles in ocean biogeochemistry and plankton productivity. In this study, we examined the presence and expression of specific planktonic nitrogenase genes (nifH) in the upper ocean (0 to 175 m) at Station ALOHA in the oligotrophic North Pacific Ocean. Clone libraries constructed from reverse-transcribed PCR-amplified mRNA revealed six unique phylotypes. Five of the nifH phylotypes grouped with sequences from unicellular and filamentous cyanobacteria, and one of the phylotypes clustered with ?-proteobacteria. The cyanobacterial nifH phylotypes retrieved included two sequence types that phylogenetically grouped with unicellular cyanobacteria (termed groups A and B), several sequences closely related (97 to 99%) to Trichodesmium spp. and Katagnymene spiralis, and two previously unreported phylotypes clustering with heterocyst-forming nifH cyanobacteria. Temporal patterns of nifH expression were evaluated using reverse-transcribed quantitative PCR amplification of nifH gene transcripts. The filamentous and presumed unicellular group A cyanobacterial phylotypes exhibited elevated nifH transcription during the day, while members of the group B (closely related to Crocosphaera watsonii) unicellular phylotype displayed greater nifH transcription at night. In situ nifH expression by all of the cyanobacterial phylotypes exhibited pronounced diel periodicity. The ?-proteobacterial phylotype had low transcript abundance and did not exhibit a clear diurnal periodicity in nifH expression. The temporal separation of nifH expression by the various phylotypes suggests that open ocean diazotrophic cyanobacteria have unique in situ physiological responses to daily fluctuations of light in the upper ocean. PMID:16151126

  8. Spatial and temporal patterns of sea ice variations in Vilkitsky strait, Russian High Arctic

    NASA Astrophysics Data System (ADS)

    Ci, T.; Cheng, X.; Hui, F.

    2013-12-01

    The Arctic Ocean has been greatly affected by climate change. Future predications show an even more drastic reduction of the ice cap which will open new areas for the exploration of natural resources and maritime transportation.Shipping through the Arctic Ocean via the Northern Sea Route (NSR) could save about 40% of the sailing distance from Asia (Yokohama) to Europe (Rotterdam) compared to the traditional route via the Suez Canal. Vilkitsky strait is the narrowest and northest portion of the Northern Sea Route with heaviest traffic between the Taimyr Peninsular and the Severnaya Zemlya archipelago. The preliminary results of sea ice variations are presented by using moderate-resolution imaging spectro radiometer(MODIS) data with 250-m resolution in the Vilkitsky strait during 2009-2012. Temporally, the first rupture on sea ice in Vilkitsky strait usually comes up in April and sea ice completely break into pieces in early June. The strait would be ice-free between August and late September. The frequency of ice floes grows while temperature falls down in October. There are always one or two months suitable for transport. Spatially, Sea ice on Laptev sea side breaks earlier than that of Kara sea side while sea ice in central of strait breaks earlier than in shoreside. The phenomena are directly related with the direction of sea wind and ocean current. In summmary, study on Spatial and temporal patterns in this area is significant for the NSR. An additional research issue to be tackled is to seeking the trends of ice-free duration in the context of global warming. Envisat ASAR data will also be used in this study.

  9. Temporal and spatial patterns of Bartonella infection in black-tailed prairie dogs (Cynomys ludovicianus).

    PubMed

    Bai, Ying; Kosoy, M Y; Ray, C; Brinkerhoff, R J; Collinge, S K

    2008-08-01

    We describe the temporal dynamics and spatial distribution of Bartonella in black-tailed prairie dogs (Cynomys ludovicianus) based on a longitudinal study conducted in 20 black-tailed prairie dog (BTPD) colonies in Boulder County, CO from 2003 to 2005. Bartonella infection was widely distributed in all colonies with an overall prevalence of 23.1%, but varied by colony from 4.8% to 42.5% and by year from 9.1 to 39.0%, with a marked increase in Bartonella activity in 2005. Levels of bacteremia varied from 40 to 12,000 colony forming units (CFU) per milliliter of BTPD blood, but were highly skewed with a median of 240 CFU. Bartonella infection rates were unimodal with respect to BTPD body mass, first increasing among growing juveniles, then declining among adults. Infection rates exhibited a sigmoidal response to body mass, such that 700g may prove to be a useful threshold value to evaluate the likelihood of Bartonella infection in BTPDs. Bartonella prevalence increased throughout the testing season for each year, as newly emerged juveniles developed bacteremia. Data from recaptured animals suggest that Bartonella infections did not persist in individual BTPDs, which may explain the relatively low prevalence of Bartonella in BTPDs compared to other rodent species. No association was found between Bartonella prevalence and host population density. Prevalence did not differ between males and females. The spatio-temporal pattern of Bartonella infection among colonies suggests epizootic spread from northern to central and southern portions of the study area. The potential significance of the BTPD-associated Bartonella for public health needs to be further investigated. PMID:18176820

  10. Linking water surface roughness to velocity patterns using terrestrial laser scanning and acoustic doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Heritage, George; Milan, David; Entwistle, Neil

    2010-05-01

    There are well established links between water surface characteristics and hydraulics. Biotope identification is currently an important part of the River Habitat Survey in England and Wales. Their differentiation is based upon recognition of a family of flow features exhibited on the water surface. Variability in this water surface ‘roughness' is dependent upon the interaction of flow with boundary roughness and flow depth. Past research that has attempted to differentiate biotopes based upon differences in Froude number (Fr) and Reynolds number (Re), however this linkage has only been limited to local analysis between flow velocity, depth and roughness. Milan et al. (2010) have recently demonstrated that terrestrial laser scanning (TLS) can be applied to produce fully quantitative maps of hydraulic habitat, based upon defined water surface roughness delimeters. However the nature of the linkages between water surface roughness, flow velocity and depth are still poorly understood, particularly at the reach-scale. This study attempts to provide a full spatial picture of the links between water surface roughness, flow depth and velocity. A Sontek Acoustic Doppler Velocity Profiler (ADVP) was used to provide detailed information on vertical velocity and water depth for a 300 m reach of the gravel-bed River Wharfe, Yorkshire, UK. Simultaneous to the ADVP measurements, a Riegl LMS-Z210 TLS was used to take a series of first return scans of the water surface. Categorisation of the point cloud elevation data for the water surface was achieved through the allocation of moving window standard deviation values to a regular grid, thus defining water surface roughness. The ADVP data demonstrate gross reach-scale variation in velocity and depth linked to bedforms, and more localised spatial and temporal variation within biotope units. The ADVP data was used to produce reach-scale maps of Fr and Re. The extent to which water surface roughness defined biotopes mapped onto these Fr and Re maps was then explored. The maps produced demonstrate a hydraulic picture that is far more complex than previously reported. It is concluded that a re-evaluation of the definition and use of biotopes to map instream river habitat is required. Reference Milan, D.J., Heritage, G.L., Large, A.R.G., Entwistle, N. 2010. Identification of hydraulic biotopes using terrestrial laser scan data of water surface properties. Earth Surface Processes & Landforms, 35, in press.

  11. Spatial and temporal seismicity patterns from dynamic trigger by great earthquakes

    NASA Astrophysics Data System (ADS)

    Johnson, C. W.; Burgmann, R.

    2013-12-01

    Questions remain regarding the dynamic triggering of large earthquakes at global distances and the role of earthquake nucleation times following dynamic stress perturbations on active faults. At distances beyond 2-3 fault lengths, transient stress changes as a result of seismic waves have been shown to trigger microseismicity in regions of geothermal activity, non-volcanic tremor, and small tectonic earthquakes, i.e. M<3, during the passage of seismic waves and subsequent days. Less frequently, immediate triggering of earthquakes ranging from 3 > M < 5 is detected during the passage of the surface wave train, whereas events M>5 are shown to experience no rate increase outside the aftershock zone of large-magnitude events. An exception to this magnitude threshold for dynamically triggered activity is the MW 8.6 2012 east Indian Ocean earthquake that resulted in above-average global seismicity for events >M5.5 in the 6 days following the mainshock (Pollitz et al., 2012 Nature) followed by a 95 day period of global quiescence for M>=6.5 events (Pollitz et al., 2013 submitted to BSSA). The activity observed following the 2012 event is an example of delayed dynamic triggering which suggests that the stress perturbations experienced during the teleseismic surface waves were large enough to advance the earthquake cycle of multiple >M5 events. Conversely, the same stress changes could suppress activity while earthquake rates return to equilibrium. Here we investigate the idea of global 'dynamic shadowing' in order to determine if a spatial and temporal relationship to large-magnitude events exists for periods of reduced global seismicity. We build on the previous work by Parsons and Velasco (2011 Nature Geoscience) who concluded that increases in M>5 seismicity are confined to within 2-3 fault lengths of the rupture and activity returned to background rates within 36 hours following a M>7 event. Using a similar methodology, we explore the suppression of global activity with respect to background earthquake activity following large magnitude events using 30 years of earthquake catalog data obtained from the Advanced National Seismic System. Our goal is to determine if a dynamic shadow effect results in a reduction of seismicity at a distinguishable level below the background seismicity over various temporal and spatial ranges following the largest cataloged earthquakes. We utilize spatial ranges consistent with maximum transient stress changes for different fault mechanisms in order to document the temporal characteristics of seismicity patterns.

  12. Spatial and temporal patterns of greenness on the Yamal Peninsula, Russia: interactions of ecological and social factors affecting the Arctic normalized difference vegetation index

    E-print Network

    Bhatt, Uma

    Spatial and temporal patterns of greenness on the Yamal Peninsula, Russia: interactions.1088/1748-9326/4/4/045004 Spatial and temporal patterns of greenness on the Yamal Peninsula, Russia: interactions of ecological, USA 2 Earth Cryosphere Institute, Russian Academy of Science, Siberian Branch, Tyumen, Russia 3

  13. Very high resolution airborne imagery for characterising spatial and temporal thermal patterns of braided rivers

    NASA Astrophysics Data System (ADS)

    Wawrzyniak, V.; Piégay, H.; Allemand, P.; Grandjean, P.

    2011-12-01

    At the catchment scale water temperature is influenced by geographical factors, but at the reach scale superficial and groundwater hydrology and channel geometry strongly affect thermal patterns. During the last 30 years, studies have been pointed out the significance and complexity of water exchanges between the channel and the hyporheic and phreatic zones. These surface-subsurface water exchanges influence water temperature patterns. Braided rivers present particular thermal conditions with very high spatial water temperature variability. This high thermal variability is difficult to comprehend using only in situ measurements and so thermal infrared (TIR) remote sensing is particularly suited to assessing the thermal patterns associated with these rivers. The aims of this study are to evaluate temperature patterns of nine braided reaches at very high spatial resolution (~20 cm) and to link temperature and water-body types. We hypothesized that river type has an influence of the spatial patterns of water temperature and that the patterns change through the day. All reaches are located in France, in the Rhône catchment. The nine reaches were selected based on high aquatic habitat diversities and are located in three regional areas: the massif des Écrins, the Rhône valley, and south Alps. They are about 1 km long. We have three distinct temporal approaches. The first one is a multi-site approach which proposes one survey of each site during summers 2010 or 2011. Three reaches were selected for the second phase (a multi-annual analysis and were therefore imaged both in summers 2010 and 2011. The last phase is an intra-day survey of two reaches with several flights at different times of day. This presentation focuses on the last approach with two reaches of the Drôme and Drac Noir rivers. To observe the evolution of the thermal patterns of these two reaches through the day, four flights within a day were realized during summer 2011 for both sites. The Drôme reach (44°44' N, 4°56' E) is characterized by a nivo-pluvial regime while the Drac Noir (44°40' N, 6°18' E) is a glacial river. Very high spatial resolution thermal images are needed because braided rivers have multiple, often narrow, channels. Satellite and aircraft TIR do not have fine enough spatial resolutions and consequently we used a drone, a helicopter and a paraglider to acquire sets of images. The three vector types were equipped with a thermal camera (7.5-14 ?m) which can detect noise equivalent temperature differences of ±0.08°C. Based on flight and camera parameter, we collected thermal images with very high spatial resolution (10-30 cm). At the same time as the thermal acquisitions, visible images were recorded and in situ measurements of water temperatures, velocities and discharges were taken.

  14. Improvement of temporal resolution in blood concentration imaging using NIR speckle patterns

    NASA Astrophysics Data System (ADS)

    Yokoi, Naomichi; Shimatani, Yuichi; Kyoso, Masaki; Funamizu, Hideki; Aizu, Yoshihisa

    2013-06-01

    In the imaging of blood concentration change using near infrared bio-speckles, temporal averaging of speckle images is necessary for speckle reduction. To improve the temporal resolution in blood concentration imaging, use of spatial averaging is investigated to measured data in rat experiments. Results show that three frames in temporal averaging with (2×2) pixels in spatial averaging can be accepted to obtain the temporal resolution of ten concentration images per second.

  15. Hierarchical Bayesian modeling of spatio-temporal patterns of lung cancer incidence risk in Georgia, USA: 2000-2007

    NASA Astrophysics Data System (ADS)

    Yin, Ping; Mu, Lan; Madden, Marguerite; Vena, John E.

    2014-10-01

    Lung cancer is the second most commonly diagnosed cancer in both men and women in Georgia, USA. However, the spatio-temporal patterns of lung cancer risk in Georgia have not been fully studied. Hierarchical Bayesian models are used here to explore the spatio-temporal patterns of lung cancer incidence risk by race and gender in Georgia for the period of 2000-2007. With the census tract level as the spatial scale and the 2-year period aggregation as the temporal scale, we compare a total of seven Bayesian spatio-temporal models including two under a separate modeling framework and five under a joint modeling framework. One joint model outperforms others based on the deviance information criterion. Results show that the northwest region of Georgia has consistently high lung cancer incidence risk for all population groups during the study period. In addition, there are inverse relationships between the socioeconomic status and the lung cancer incidence risk among all Georgian population groups, and the relationships in males are stronger than those in females. By mapping more reliable variations in lung cancer incidence risk at a relatively fine spatio-temporal scale for different Georgian population groups, our study aims to better support healthcare performance assessment, etiological hypothesis generation, and health policy making.

  16. Multivariate pattern analysis reveals anatomical connectivity differences between the left and right mesial temporal lobe epilepsy

    PubMed Central

    Fang, Peng; An, Jie; Zeng, Ling-Li; Shen, Hui; Chen, Fanglin; Wang, Wensheng; Qiu, Shijun; Hu, Dewen

    2015-01-01

    Previous studies have demonstrated differences of clinical signs and functional brain network organizations between the left and right mesial temporal lobe epilepsy (mTLE), but the anatomical connectivity differences underlying functional variance between the left and right mTLE remain uncharacterized. We examined 43 (22 left, 21 right) mTLE patients with hippocampal sclerosis and 39 healthy controls using diffusion tensor imaging. After the whole-brain anatomical networks were constructed for each subject, multivariate pattern analysis was applied to classify the left mTLE from the right mTLE and extract the anatomical connectivity differences between the left and right mTLE patients. The classification results reveal 93.0% accuracy for the left mTLE versus the right mTLE, 93.4% accuracy for the left mTLE versus controls and 90.0% accuracy for the right mTLE versus controls. Compared with the right mTLE, the left mTLE exhibited a different connectivity pattern in the cortical-limbic network and cerebellum. The majority of the most discriminating anatomical connections were located within or across the cortical-limbic network and cerebellum, thereby indicating that these disease-related anatomical network alterations may give rise to a portion of the complex of emotional and memory deficit between the left and right mTLE. Moreover, the orbitofrontal gyrus, cingulate cortex, hippocampus and parahippocampal gyrus, which exhibit high discriminative power in classification, may play critical roles in the pathophysiology of mTLE. The current study demonstrated that anatomical connectivity differences between the left mTLE and the right mTLE may have the potential to serve as a neuroimaging biomarker to guide personalized diagnosis of the left and right mTLE. PMID:25844312

  17. Convective rain cells: radar-derived spatio-temporal characteristics and synoptic patterns

    NASA Astrophysics Data System (ADS)

    Peleg, N.; Morin, E.

    2012-04-01

    In this study we present the spatiotemporal characteristics of convective rain cells over the Eastern Mediterranean (northern Israel) and their relationship to synoptic patterns. Information on rain cell features was extracted from high-resolution weather radar data for a total of 191,586 radar volume scans from 12 hydrological years. The convective rain cell features (i.e., cell area, rainfall intensity and cell orientation) were obtained using cell segmentation technique. Cell tracking algorithm was used to analyze the changes of those features over time. Convective rain cells were clustered into three synoptic types (two extratropical winter lows: deep Cyprus low and shallow low, and a tropical intrusion: Active Red Sea Trough) using several NCEP/NCAR parameters, and empirical distributions were computed for their spatial and temporal features. In the study region, it was found that the Active Red Sea Trough rain cells are larger, live for less time and possess lower rain intensities than the rain cells generated by the winter lows. The Cyprus low rain cells were found to be less intense and slightly larger on average than the shallow low rain cells. It was further discovered that the preferential orientation of the rain cells is associated with the direction and velocity of the wind. The effect of distance from the coastline was also examined. An increase in the number and area of the rain cells near the coastline was observed, presumably due to the sea breeze convection. The mean rainfall intensity was found to peak near the shore and decrease with distance inland. This information is of great importance for understanding rain patterns and can be further applied in exploring the hydrological responses of the basins in this region. The presented study is the first step in achieving the long-term goal: to develop a high space-time resolution weather generator for creating rainfall ensembles under different climatology scenarios. Those rainfall ensembles will be incorporated into hydrological models for simulating hydrological response under predicted climate changes.

  18. Convergence and Divergence in the Evolution of Cat Skulls: Temporal and Spatial Patterns of Morphological Diversity

    PubMed Central

    Sakamoto, Manabu; Ruta, Marcello

    2012-01-01

    Background Studies of biological shape evolution are greatly enhanced when framed in a phylogenetic perspective. Inclusion of fossils amplifies the scope of macroevolutionary research, offers a deep-time perspective on tempo and mode of radiations, and elucidates life-trait changes. We explore the evolution of skull shape in felids (cats) through morphometric analyses of linear variables, phylogenetic comparative methods, and a new cladistic study of saber-toothed cats. Methodology/Principal Findings A new phylogenetic analysis supports the monophyly of saber-toothed cats (Machairodontinae) exclusive of Felinae and some basal felids, but does not support the monophyly of various saber-toothed tribes and genera. We quantified skull shape variation in 34 extant and 18 extinct species using size-adjusted linear variables. These distinguish taxonomic group membership with high accuracy. Patterns of morphospace occupation are consistent with previous analyses, for example, in showing a size gradient along the primary axis of shape variation and a separation between large and small-medium cats. By combining the new phylogeny with a molecular tree of extant Felinae, we built a chronophylomorphospace (a phylogeny superimposed onto a two-dimensional morphospace through time). The evolutionary history of cats was characterized by two major episodes of morphological divergence, one marking the separation between saber-toothed and modern cats, the other marking the split between large and small-medium cats. Conclusions/Significance Ancestors of large cats in the ‘Panthera’ lineage tend to occupy, at a much later stage, morphospace regions previously occupied by saber-toothed cats. The latter radiated out into new morphospace regions peripheral to those of extant large cats. The separation between large and small-medium cats was marked by considerable morphologically divergent trajectories early in feline evolution. A chronophylomorphospace has wider applications in reconstructing temporal transitions across two-dimensional trait spaces, can be used in ecophenotypical and functional diversity studies, and may reveal novel patterns of morphospace occupation. PMID:22792186

  19. Optimized temporally deconvolved Ca²? imaging allows identification of spatiotemporal activity patterns of CA1 hippocampal ensembles.

    PubMed

    Pfeiffer, Thomas; Draguhn, Andreas; Reichinnek, Susanne; Both, Martin

    2014-07-01

    Hippocampal activity is characterized by the coordinated firing of a subset of neurons. Such neuronal ensembles can either be driven by external stimuli to form new memory traces or be reactivated by intrinsic mechanisms to reactivate and consolidate old memories. Hippocampal network oscillations orchestrate this coherent activity. One key question is how the topology, i.e. the functional connectivity of neuronal networks supports their desired function. Recently, this has been addressed by characterizing the intrinsic properties for the highly recurrently connected CA3 region using organotypic slice cultures and Ca(2+) imaging. In the present study, we aimed to determine the properties of CA1 hippocampal ensembles at high temporal and multiple single cell resolution. Thus, we performed Ca(2+) imaging using the chemical fluorescent Ca(2+) indicator Oregon Green BAPTA 1-AM. To achieve most physiological conditions, we used acute hippocampal slices that were recorded in a so-called interface chamber. To faithfully reconstruct firing patterns of multiple neurons in the field of view, we optimized deconvolution-based detection of action potential associated Ca(2+) events. Our approach outperformed currently available detection algorithms by its sensitivity and robustness. In combination with advanced network analysis, we found that acute hippocampal slices contain a median of 11 CA1 neuronal ensembles with a median size of 4 neurons. This apparently low number of neurons is likely due to the confocal imaging acquisition and therefore yields a lower limit. The distribution of ensemble sizes was compatible with a scale-free topology, as far as can be judged from data with small cell numbers. Interestingly, cells were more tightly clustered in large ensembles than in smaller groups. Together, our data show that spatiotemporal activity patterns of hippocampal neuronal ensembles can be reliably detected with deconvolution-based imaging techniques in mouse hippocampal slices. The here presented techniques are fully applicable to similar studies of distributed optical measurements of neuronal activity (in vivo), where signal-to-noise ratio is critical. PMID:24650598

  20. Reconstructing spatio-temporal patterns of debris-flow activity using dendrogeomorphological methods

    NASA Astrophysics Data System (ADS)

    Bollschweiler, Michelle; Stoffel, Markus; Ehmisch, Melanie; Monbaron, Michel

    2007-07-01

    Debris flows are a major threat in many parts of the Alps, where they repeatedly cause severe damage to infrastructure and transportation corridors or even loss of life. Nonetheless, the spatial behavior of past debris-flow activity and the analysis of areas affected during particular events have been widely neglected in reconstructions so far. It was therefore the purpose of this study to reconstruct spatio-temporal patterns of past debris flows on a forested cone in the Swiss Alps (Bruchji torrent, Blatten, Valais). The analysis of past events was based on a detailed geomorphic map (1:1000) of all forms related to debris flows as well as on tree-ring series from 401 heavily affected trees ( Larix decidua Mill. and Picea abies (L.) Karst.) growing in or next to deposits. The samples were analyzed and growth disturbances related to debris-flow activity assessed, such as tangential rows of traumatic resin ducts, the onset of reaction wood or abrupt growth suppression or release. In total, 960 growth disturbances were identified in the samples, belonging to 40 different event years between A.D. 1867 and 2005. In addition, the coupling of tree-ring data with the geomorphic map allowed reconstruction of eleven formerly active channels and spatial representation of individual events. Based on our results we believe that before 1935, debris flows preferentially used those channels located in the western part of the cone, whereas the eastern part of the cone remained widely unaffected. The spatial representation of the 40 events also allowed identification of five different spatial patterns for debris flows at the study site.

  1. Age-related changes in trunk neuromuscular activation patterns during a controlled functional transfer task include amplitude and temporal synergies.

    PubMed

    Quirk, D Adam; Hubley-Kozey, Cheryl L

    2014-12-01

    While healthy aging is associated with physiological changes that can impair control of trunk motion, few studies examine how spinal muscle responses change with increasing age. This study examined whether older (over 65 years) compared to younger (20-45 years) adults had higher overall amplitude and altered temporal recruitment patterns of trunk musculature when performing a functional transfer task. Surface electromyograms from twelve bilateral trunk muscle (24) sites were analyzed using principal component analysis, extracting amplitude and temporal features (PCs) from electromyographic waveforms. Two PCs explained 96% of the waveform variance. Three factor ANOVA models tested main effects (group, muscle and reach) and interactions for PC scores. Significant (p<.0125) group interactions were found for all PC scores. Post hoc analysis revealed that relative to younger adults, older adults recruited higher agonist and antagonistic activity, demonstrated continuous activation levels in specific muscle sites despite changing external moments, and had altered temporal synergies within abdominal and back musculature. In summary both older and younger adults recruit highly organized activation patterns in response to changing external moments. Differences in temporal trunk musculature recruitment patterns suggest that older adults experience different dynamic spinal stiffness and loading compared to younger adults during a functional lifting task. PMID:25457424

  2. Temporal patterns in the intertidal faunal community at the mouth of a tropical estuary.

    PubMed

    Lacerda, C H F; Barletta, M; Dantas, D V

    2014-11-01

    The use of intertidal sandy beaches by fish and macrocrustaceans was studied at different temporal scales at the mouth of a tropical estuary. Samples were taken along the lunar and diel cycles in the late dry and rainy seasons. Fish assemblage (number of species, density and biomass), crustaceans and wrack biomass, showed significant interactions among all studied factors, and the combination of moon phase and diel cycle, resulting in different patterns of environmental variables (depth, water temperature and dissolved oxygen), affected habitat use by the different species. Variances in faunal community were detected between seasons, stimulated by salinity fluctuations from freshwater input during the rainy season. These differences suggest an important cycling of habitats and an increase in connectivity between adjacent habitats (estuary and coastal waters). Moreover, the results showed that this intertidal sandy beach also provides an alternative nursery and protected shallow-water area for the initial development phase of many marine and estuarine species. In addition, this intertidal habitat plays an important role in the maintenance of the ecological functioning of the estuarine-coastal ecosystem continuum. PMID:25315884

  3. Temporal patterns of gene expression in developing maize endosperm identified through transcriptome sequencing

    PubMed Central

    Li, Guosheng; Wang, Dongfang; Yang, Ruolin; Logan, Kyle; Chen, Hao; Zhang, Shanshan; Skaggs, Megan I.; Lloyd, Alan; Burnett, William J.; Laurie, John D.; Hunter, Brenda G.; Dannenhoffer, Joanne M.; Larkins, Brian A.; Drews, Gary N.; Wang, Xiangfeng; Yadegari, Ramin

    2014-01-01

    Endosperm is a filial structure resulting from a second fertilization event in angiosperms. As an absorptive storage organ, endosperm plays an essential role in support of embryo development and seedling germination. The accumulation of carbohydrate and protein storage products in cereal endosperm provides humanity with a major portion of its food, feed, and renewable resources. Little is known regarding the regulatory gene networks controlling endosperm proliferation and differentiation. As a first step toward understanding these networks, we profiled all mRNAs in the maize kernel and endosperm at eight successive stages during the first 12 d after pollination. Analysis of these gene sets identified temporal programs of gene expression, including hundreds of transcription-factor genes. We found a close correlation of the sequentially expressed gene sets with distinct cellular and metabolic programs in distinct compartments of the developing endosperm. The results constitute a preliminary atlas of spatiotemporal patterns of endosperm gene expression in support of future efforts for understanding the underlying mechanisms that control seed yield and quality. PMID:24821765

  4. Temporal patterns of infiltration into a water repellent soil under field conditions

    NASA Astrophysics Data System (ADS)

    Ward, Phil; Roper, Margaret; Micin, Shayne; Jongepier, Ramona

    2014-05-01

    Water repellency causes substantial economic losses for farmers in southern Australia through impacts on crop growth and weed germination. However, recent research has demonstrated that laboratory measurements of water repellency may not be a reliable indicator of the severity of symptoms experienced in the field. In particular, crop residue retention and minimal soil disturbance led to increased water repellency, but was also associated with higher soil water contents measured at strategic times of the year. Little is known about the temporal patterns of soil water storage close to the soil surface in a water repellent sand. In this research we measured soil water content at a depth of 0.05 m at 15-minute intervals from June 2011 to October 2012, under various treatment combinations of residue retention and soil disturbance. Measurements were made in both 'crop row' and 'crop inter-row' positions. For a rainfall event (9.2 mm) in March 2012, prior to crop seeding, plots previously established with no-till absorbed significantly more water (increase in soil water content of 0.074 v/v) than plots conventionally cultivated (0.038 v/v). In June 2012 (12.6 mm), 4 weeks after crop seeding, tillage was again significant, and there was a significant interaction between tillage and 'row' or 'inter-row' position. These results demonstrate the importance of crop management in modifying the response of water repellent soils to rainfall in the field.

  5. CT Scans in Young People in Great Britain: Temporal and Descriptive Patterns, 1993–2002

    PubMed Central

    Pearce, Mark S.; Salotti, Jane A.; Howe, Nicola L.; McHugh, Kieran; Kim, Kwang Pyo; Lee, Choonsik; Craft, Alan W.; Berrington de Gonzaléz, Amy; Parker, Louise

    2012-01-01

    Background. Although using computed tomography (CT) can be greatly beneficial, the associated relatively high radiation doses have led to growing concerns in relation to potential associations with risk of future cancer. Very little has been published regarding the trends of CT use in young people. Therefore, our objective was to assess temporal and other patterns in CT usage among patients aged under 22 years in Great Britain from 1993 to 2002. Methods. Electronic data were obtained from the Radiology Information Systems of 81 hospital trusts within Great Britain. All included patients were aged under 22 years and examined using CT between 1993 and 2002, with accessible radiology records. Results. The number of CT examinations doubled over the study period. While increases in numbers of recorded examinations were seen across all age groups, the greatest increases were in the older patients, most notably those aged 15–19 years of age. Sixty percent of CT examinations were of the head, with the percentages varying with calendar year and patient age. Conclusions. In contrast to previous data from the North of England, the doubling of CT use was not accompanied by an increase in numbers of multiple examinations to the same individual. PMID:22792457

  6. We'll Meet Again: Revealing Distributional and Temporal Patterns of Social Contact

    PubMed Central

    Pachur, Thorsten; Schooler, Lael J.; Stevens, Jeffrey R.

    2014-01-01

    What are the dynamics and regularities underlying social contact, and how can contact with the people in one's social network be predicted? In order to characterize distributional and temporal patterns underlying contact probability, we asked 40 participants to keep a diary of their social contacts for 100 consecutive days. Using a memory framework previously used to study environmental regularities, we predicted that the probability of future contact would follow in systematic ways from the frequency, recency, and spacing of previous contact. The distribution of contact probability across the members of a person's social network was highly skewed, following an exponential function. As predicted, it emerged that future contact scaled linearly with frequency of past contact, proportionally to a power function with recency of past contact, and differentially according to the spacing of past contact. These relations emerged across different contact media and irrespective of whether the participant initiated or received contact. We discuss how the identification of these regularities might inspire more realistic analyses of behavior in social networks (e.g., attitude formation, cooperation). PMID:24475073

  7. Spatio-temporal patterns of genome evolution in allotetraploid species of the genus Oryza.

    PubMed

    Ammiraju, Jetty S S; Fan, Chuanzhu; Yu, Yeisoo; Song, Xiang; Cranston, Karen A; Pontaroli, Ana Clara; Lu, Fei; Sanyal, Abhijit; Jiang, Ning; Rambo, Teri; Currie, Jennifer; Collura, Kristi; Talag, Jayson; Bennetzen, Jeffrey L; Chen, Mingsheng; Jackson, Scott; Wing, Rod A

    2010-08-01

    Despite knowledge that polyploidy is widespread and a major evolutionary force in flowering plant diversification, detailed comparative molecular studies on polyploidy have been confined to only a few species and families. The genus Oryza is composed of 23 species that are classified into ten distinct 'genome types' (six diploid and four polyploid), and is emerging as a powerful new model system to study polyploidy. Here we report the identification, sequence and comprehensive comparative annotation of eight homoeologous genomes from a single orthologous region (Adh1-Adh2) from four allopolyploid species representing each of the known Oryza genome types (BC, CD, HJ and KL). Detailed comparative phylogenomic analyses of these regions within and across species and ploidy levels provided several insights into the spatio-temporal dynamics of genome organization and evolution of this region in 'natural' polyploids of Oryza. The major findings of this study are that: (i) homoeologous genomic regions within the same nucleus experience both independent and parallel evolution, (ii) differential lineage-specific selection pressures do not occur between polyploids and their diploid progenitors, (iii) there have been no dramatic structural changes relative to the diploid ancestors, (iv) a variation in the molecular evolutionary rate exists between the two genomes in the BC complex species even though the BC and CD polyploid species appear to have arisen <2?million years ago, and (v) there are no clear distinctions in the patterns of genome evolution in the diploid versus polyploid species. PMID:20487382

  8. Multi-voxel pattern analysis of noun and verb differences in ventral temporal cortex.

    PubMed

    Boylan, Christine; Trueswell, John C; Thompson-Schill, Sharon L

    2014-10-01

    Recent evidence suggests a probabilistic relationship exists between the phonological/orthographic form of a word and its lexical-syntactic category (specifically nouns vs. verbs) such that syntactic prediction may elicit form-based estimates in sensory cortex. We tested this hypothesis by conducting multi-voxel pattern analysis (MVPA) of fMRI data from early visual cortex (EVC), left ventral temporal (VT) cortex, and a subregion of the latter - the left mid fusiform gyrus (mid FG), sometimes called the "visual word form area." Crucially, we examined only those volumes sampled when subjects were predicting, but not viewing, nouns and verbs. This allowed us to investigate prediction effects in visual areas without any bottom-up orthographic input. We found that voxels in VT and mid FG, but not in EVC, were able to classify noun-predictive trials vs. verb-predictive trials in sentence contexts, suggesting that sentence-level predictions are sufficient to generate word form-based estimates in visual areas. PMID:25156159

  9. Temporal-spatial neural activation patterns linked to perceptual encoding of emotional salience.

    PubMed

    Todd, Rebecca M; Taylor, Margot J; Robertson, Amanda; Cassel, Daniel B; Doesberg, Sam M; Lee, Daniel H; Shek, Pang N; Pang, Elizabeth W

    2014-01-01

    It is well known that we continuously filter incoming sensory information, selectively allocating attention to what is important while suppressing distracting or irrelevant information. Yet questions remain about spatiotemporal patterns of neural processes underlying attentional biases toward emotionally significant aspects of the world. One index of affectively biased attention is an emotional variant of an attentional blink (AB) paradigm, which reveals enhanced perceptual encoding for emotionally salient over neutral stimuli under conditions of limited executive attention. The present study took advantage of the high spatial and temporal resolution of magnetoencephalography (MEG) to investigate neural activation related to emotional and neutral targets in an AB task. MEG data were collected while participants performed a rapid stimulus visual presentation task in which two target stimuli were embedded in a stream of distractor words. The first target (T1) was a number and the second (T2) either an emotionally salient or neutral word. Behavioural results replicated previous findings of greater accuracy for emotionally salient than neutral T2 words. MEG source analyses showed that activation in orbitofrontal cortex, characterized by greater power in the theta and alpha bands, and dorsolateral prefrontal activation were associated with successful perceptual encoding of emotionally salient relative to neutral words. These effects were observed between 250 and 550 ms, latencies associated with discrimination of perceived from unperceived stimuli. These data suggest that important nodes of both emotional salience and frontoparietal executive systems are associated with the emotional modulation of the attentional blink. PMID:24727751

  10. Discovering temporal patterns in water quality time series, focusing on floods with the LDA method

    NASA Astrophysics Data System (ADS)

    Hélène Aubert, Alice; Tavenard, Romain; Emonet, Rémi; Malinowski, Simon; Guyet, Thomas; Quiniou, René; Odobez, Jean-Marc; Gascuel-Odoux, Chantal

    2013-04-01

    Studying floods has been a major issue in hydrological research for years. It is often done in terms of water quantity but it is also of interest in terms of water quality. Stream chemistry is a mix of solutes. They originate from various sources in the catchment, reach the stream by various flow pathways and are transformed by biogeochemical reactions at different locations. Therefore, we hypothesized that reaction of the stream chemistry to a rainfall event is not unique but varies according to the season (1), and the global meteorological conditions of the year (2). Identifying a typology of temporal chemical patterns of reaction to a rainfall event is a way to better understand catchment processes at the flood time scale. To answer this issue, we applied a probabilistic model (Latent Dirichlet Allocation or LDA (3)) mining recurrent sequential patterns to a dataset of floods. The dataset is 12 years long and daily recorded. It gathers a broad range of parameters from which we selected rainfall, discharge, water table depth, temperature as well as nitrate, dissolved organic carbon, sulphate and chloride concentrations. It comes from a long-term hydrological observatory (AgrHys, western France) located at Kervidy-Naizin. A set of 472 floods was automatically extracted (4). From each flood, a document has been generated that is made of a set of "hydrological words". Each hydrological word corresponds to a measurement: it is a triplet made of the considered variable, the time at which the measurement is made (relative to the beginning of the flood), and its magnitude (that can be low, medium or high). The documents are used as input data to the LDA algorithm. LDA relies on spotting co-occurrences (as an alternative to the more traditional study of correlation) between words that appear within the flood documents. It has two nice properties that are its ability to easily deal with missing data and its additive property that allows a document to be seen as a mixture of several flood patterns. The output of LDA is a set of patterns that can easily be represented in graphics. These patterns correspond to typical reactions to rainfall events. The patterns themselves are carefully studied, as well as their repartition along the year and along the 12 years of the dataset. The novelties are fourfold. First, as a methodological point of view, we learn that hydrological data can be analyzed with this LDA model giving a typology of a multivariate chemical signature of floods. Second, we outline that chemistry parameters are sufficient to obtain meaningful patterns. There is no need to include hydro-meteorological parameters to define the patterns. However, hydro-meteorological parameters are useful to understand the processes leading to these patterns. Third, our hypothesis of seasonal specific reaction to rainfall is verified, moreover detailed; so is our hypothesis of different reactions to rainfall for years with different hydro-meteorological conditions. Fourth, this method allows the consideration of overlapping floods that are usually not studied. We would recommend the use of such model to study chemical reactions of stream after rainfall events, or more broadly after any hydrological events. The typology that has been provided by this method is a kind of bar code of water chemistry during floods. It could be well suited to compare different geographical locations by using the same patterns and analysing the resulting different pattern distributions. (1) Aubert, A.H. et al., 2012. The chemical signature of a livestock farming catchment: synthesis from a high-frequency multi-element long term monitoring. HESSD, 9(8): 9715 - 9741. (2) Aubert, A.H., Gascuel-Odoux, C., Merot, P., 2013. Annual hysteresis of water quality: A method to analyse the effect of intra- and inter-annual climatic conditions. Journal of Hydrology, 478(0): 29-39. (3) Blei, D. M.; Ng, A. Y.; Jordan, M. I., 2003. Latent Dirichlet allocation. Journal of Machine Learning Research, 3(4-5): 993-1022. (4) de Lavenne, A., Cudennec, C., Streamflow velocity

  11. Spatial and Temporal Pattern of Rift Valley Fever Outbreaks in Tanzania; 1930 to 2007

    PubMed Central

    Sindato, Calvin; Karimuribo, Esron D.; Pfeiffer, Dirk U.; Mboera, Leonard E. G.; Kivaria, Fredrick; Dautu, George; Bernard, Bett; Paweska, Janusz T.

    2014-01-01

    Background Rift Valley fever (RVF)-like disease was first reported in Tanzania more than eight decades ago and the last large outbreak of the disease occurred in 2006–07. This study investigates the spatial and temporal pattern of RVF outbreaks in Tanzania over the past 80 years in order to guide prevention and control strategies. Materials and Methods A retrospective study was carried out based on disease reporting data from Tanzania at district or village level. The data were sourced from the Ministries responsible for livestock and human health, Tanzania Meteorological Agency and research institutions involved in RVF surveillance and diagnosis. The spatial distribution of outbreaks was mapped using ArcGIS 10. The space-time permutation model was applied to identify clusters of cases, and a multivariable logistic regression model was used to identify risk factors associated with the occurrence of outbreaks in the district. Principal Findings RVF outbreaks were reported between December and June in 1930, 1947, 1957, 1960, 1963, 1968, 1977–79, 1989, 1997–98 and 2006–07 in 39.2% of the districts in Tanzania. There was statistically significant spatio-temporal clustering of outbreaks. RVF occurrence was associated with the eastern Rift Valley ecosystem (OR?=?6.14, CI: 1.96, 19.28), total amount of rainfall of >405.4 mm (OR?=?12.36, CI: 3.06, 49.88), soil texture (clay [OR?=?8.76, CI: 2.52, 30.50], and loam [OR?=?8.79, CI: 2.04, 37.82]). Conclusion/Significance RVF outbreaks were found to be distributed heterogeneously and transmission dynamics appeared to vary between areas. The sequence of outbreak waves, continuously cover more parts of the country. Whenever infection has been introduced into an area, it is likely to be involved in future outbreaks. The cases were more likely to be reported from the eastern Rift Valley than from the western Rift Valley ecosystem and from areas with clay and loam rather than sandy soil texture. PMID:24586433

  12. Geospatial and temporal patterns of annual cholera outbreaks in Matlab, Bangladesh

    NASA Astrophysics Data System (ADS)

    Majumder, M. S.; de Klerk, K.; Meyers, D.

    2012-12-01

    Cholera is a waterborne diarrheal disease endemic to Bangladesh, resulting in 1 million diagnoses annually. Such disease burden results in incalculable lost wages and treatment expenses, taken from the pockets of an already impoverished society. Two seasonally correlated outbreaks of cholera occur in Bangladesh every year. In the spring and early summer, the Bay of Bengal - which serves as a natural reservoir for the cholera bacteria - flows inland, causing the first outbreak amongst coastal communities. Waste containing the cholera bacteria enters the sewage system and remains untreated due to poor water and sanitation infrastructure. Therefore, during the following monsoon season, flooding of cholera-contaminated sewage into drinking water sources results in a second outbreak. Though considered common knowledge among local populations, this geographic and temporal progression has not been empirically verified in the current literature. The aim of our ongoing study is to systematically analyze the seasonal trajectory of endemic cholera in Bangladesh. This paper discusses the results obtained from a comprehensive survey of available cholera data from the International Centre of Diarrheal Disease Research, Bangladesh (ICDDR,B) in Matlab, Bangladesh. Matlab thana is a near-coastal community that consists of 142 villages. Monsoon season takes place from June through October. Due to its proximity to the Meghna River, which opens into the Bay of Bengal, the area experiences significant flooding during these months. Using 10 years of geographically referenced cholera data, cases were plotted in time and space. Preliminary patterns suggest that villages closer to the Meghna River experience the majority of the area's cholera outbreaks and that case count is highest in late spring and late fall. April/May and November/December represent 25% and 23% of total annual case counts respectively. Moreover, villages further from the coastline demonstrate 57% higher relative prevalence in fall than in the spring. Such initial results demonstrate great promise in advancing our present knowledge of endemic cholera in Bangladesh. By improving our understanding of cholera proliferating in time and space, disease mitigation resources can be distributed to the most susceptible areas when they need them most. The next step forward for our ongoing study involves the use of mobile health (mHealth) case surveillance and cloud computing for real-time geographic and temporal cholera data acquisition.

  13. Sequence-based mapping approach to spatio-temporal snow patterns from MODIS time-series applied to Scotland

    NASA Astrophysics Data System (ADS)

    Poggio, Laura; Gimona, Alessandro

    2015-02-01

    Snow cover and its monitoring are important because of the impact on important environmental variables, hydrological circulation and ecosystem services. For regional snow cover mapping and monitoring, the MODIS satellite sensors are particularly appealing. However cloud presence is an important limiting factor. This study addressed the problem of cloud cover for time-series in a boreal-Atlantic region where melting and re-covering of snow often do not follow the usual alpine-like patterns. A key requirement in this context was to apply improved methods to deal with the high cloud cover and the irregular spatio-temporal snow occurrence, through exploitation of space-time correlation of pixel values. The information contained in snow presence sequences was then used to derive summary indices to describe the time series patterns. Finally it was tested whether the derived indices can be considered an accurate summary of the snow presence data by establishing and evaluating their statistical relations with morphology and the landscape. The proposed cloud filling method had a good agreement (between 80 and 99%) with validation data even with a large number of pixels missing. The sequence analysis algorithm proposed takes into account the position of the states to fully consider the temporal dimension, i.e. the order in which a certain state appears in an image sequence compared to its neighbourhoods. The indices that were derived from the sequence of snow presence proved useful for describing the general spatio-temporal patterns of snow in Scotland as they were well related (more than 60% of explained deviance) with environmental information such as morphology supporting their use as a summary of snow patterns over time. The use of the derived indices is an advantage because of data reduction, easier interpretability and capture of sequence position-wise information (e.g. importance of short term fall/melt cycles). The derived seven clusters took into account the temporal patterns of the snow presence and they were well separated both spatially and according to the snow patterns and the environmental information. In conclusion, the use of sequences proved useful for analysing different spatio-temporal patterns of snow that could be related to other environmental information to characterize snow regimes regions in Scotland and to be integrated with ground measures for further hydrological and climatological analysis as baseline data for climate change models.

  14. Acoustic telemetry reveals large-scale migration patterns of walleye in Lake Huron.

    PubMed

    Hayden, Todd A; Holbrook, Christopher M; Fielder, David G; Vandergoot, Christopher S; Bergstedt, Roger A; Dettmers, John M; Krueger, Charles C; Cooke, Steven J

    2014-01-01

    Fish migration in large freshwater lacustrine systems such as the Laurentian Great Lakes is not well understood. The walleye (Sander vitreus) is an economically and ecologically important native fish species throughout the Great Lakes. In Lake Huron walleye has recently undergone a population expansion as a result of recovery of the primary stock, stemming from changing food web dynamics. During 2011 and 2012, we used acoustic telemetry to document the timing and spatial scale of walleye migration in Lake Huron and Saginaw Bay. Spawning walleye (n = 199) collected from a tributary of Saginaw Bay were implanted with acoustic tags and their migrations were documented using acoustic receivers (n = 140) deployed throughout U.S. nearshore waters of Lake Huron. Three migration pathways were described using multistate mark-recapture models. Models were evaluated using the Akaike Information Criterion. Fish sex did not influence migratory behavior but did affect migration rate and walleye were detected on all acoustic receiver lines. Most (95%) tagged fish migrated downstream from the riverine tagging and release location to Saginaw Bay, and 37% of these fish emigrated from Saginaw Bay into Lake Huron. Remarkably, 8% of walleye that emigrated from Saginaw Bay were detected at the acoustic receiver line located farthest from the release location more than 350 km away. Most (64%) walleye returned to the Saginaw River in 2012, presumably for spawning. Our findings reveal that fish from this stock use virtually the entirety of U.S. nearshore waters of Lake Huron. PMID:25506913

  15. Acoustic Telemetry Reveals Large-Scale Migration Patterns of Walleye in Lake Huron

    PubMed Central

    Hayden, Todd A.; Holbrook, Christopher M.; Fielder, David G.; Vandergoot, Christopher S.; Bergstedt, Roger A.; Dettmers, John M.; Krueger, Charles C.; Cooke, Steven J.

    2014-01-01

    Fish migration in large freshwater lacustrine systems such as the Laurentian Great Lakes is not well understood. The walleye (Sander vitreus) is an economically and ecologically important native fish species throughout the Great Lakes. In Lake Huron walleye has recently undergone a population expansion as a result of recovery of the primary stock, stemming from changing food web dynamics. During 2011 and 2012, we used acoustic telemetry to document the timing and spatial scale of walleye migration in Lake Huron and Saginaw Bay. Spawning walleye (n?=?199) collected from a tributary of Saginaw Bay were implanted with acoustic tags and their migrations were documented using acoustic receivers (n?=?140) deployed throughout U.S. nearshore waters of Lake Huron. Three migration pathways were described using multistate mark-recapture models. Models were evaluated using the Akaike Information Criterion. Fish sex did not influence migratory behavior but did affect migration rate and walleye were detected on all acoustic receiver lines. Most (95%) tagged fish migrated downstream from the riverine tagging and release location to Saginaw Bay, and 37% of these fish emigrated from Saginaw Bay into Lake Huron. Remarkably, 8% of walleye that emigrated from Saginaw Bay were detected at the acoustic receiver line located farthest from the release location more than 350 km away. Most (64%) walleye returned to the Saginaw River in 2012, presumably for spawning. Our findings reveal that fish from this stock use virtually the entirety of U.S. nearshore waters of Lake Huron. PMID:25506913

  16. Soft computing analysis of the possible correlation between temporal and energy release patterns in seismic activity

    NASA Astrophysics Data System (ADS)

    Konstantaras, Anthony; Katsifarakis, Emmanouil; Artzouxaltzis, Xristos; Makris, John; Vallianatos, Filippos; Varley, Martin

    2010-05-01

    This paper is a preliminary investigation of the possible correlation of temporal and energy release patterns of seismic activity involving the preparation processes of consecutive sizeable seismic events [1,2]. The background idea is that during periods of low-level seismic activity, stress processes in the crust accumulate energy at the seismogenic area whilst larger seismic events act as a decongesting mechanism releasing considerable energy [3,4]. A dynamic algorithm is being developed aiming to identify and cluster pre- and post- seismic events to the main earthquake following on research carried out by Zubkov [5] and Dobrovolsky [6,7]. This clustering technique along with energy release equations dependent on Richter's scale [8,9] allow for an estimate to be drawn regarding the amount of the energy being released by the seismic sequence. The above approach is being implemented as a monitoring tool to investigate the behaviour of the underlying energy management system by introducing this information to various neural [10,11] and soft computing models [1,12,13,14]. The incorporation of intelligent systems aims towards the detection and simulation of the possible relationship between energy release patterns and time-intervals among consecutive sizeable earthquakes [1,15]. Anticipated successful training of the imported intelligent systems may result in a real-time, on-line processing methodology [1,16] capable to dynamically approximate the time-interval between the latest and the next forthcoming sizeable seismic event by monitoring the energy release process in a specific seismogenic area. Indexing terms: pattern recognition, long-term earthquake precursors, neural networks, soft computing, earthquake occurrence intervals References [1] Konstantaras A., Vallianatos F., Varley M.R. and Makris J. P.: ‘Soft computing modelling of seismicity in the southern Hellenic arc', IEEE Geoscience and Remote Sensing Letters, vol. 5 (3), pp. 323-327, 2008 [2] Eneva M. and Ben-Zion Y.: ‘Techniques and parameters to analyze seismicity patterns associated with large earthquakes', Geophysics Res., vol. 102, pp. 17785-17795, 1997a [3] Habermann R. E.: ‘Precursory seismic quiescence: past, present and future', Pure Applied Geophysics, vol. 126, pp. 279-318, 1988 [4] Matthews M. V. and Reasenberg P. A.: ‘Statistical methods for investigating quiescence and other temporal seismicity patterns', Pure Applied Geophysics, vol. 126, pp. 357-372, 1988 [5] Zubkov S. I.: ‘The appearance times of earthquake precursors', Izv. Akad. Nauk SSSR Fiz. Zemli (Solid Earth), No. 5, pp. 87-91, 1987 [6] Dobrovolsky I. P., Zubkov S. I. and Miachkin V. I.: ‘Estimation of the size of earthquake preparation zones', Pageoph, vol. 117, pp. 1025-1044, 1979 [7] Dobrovolsky I. P., Gershenzon N. I. And Gokhberg M. B.: ‘Theory of electrokinetic effects occurring at the final stage in the preparation of a tectonic earthquake', Physics of the Earth and Planetary Interiors, vol. 57, pp. 144-156, 1989 [8] Richter C. F.: ‘Elementary Seismology', W.H.Freeman and Co., San Francisco, 1958 [9] Choy G. L. and Boatwright J. L.: ‘Global patterns of radiated seismic energy and apparent stress', Journal of Geophysical Research, vol. 84 (B5), pp. 2348-2350, 1995 [10] Haykin S.: ‘Neural Networks', 2nd Edition, Prentice Hall, 1999 [11] Jang J., Sun T. and Mizutany E.: ‘Neuro-fuzzy and soft computing', Prentice Hall, Upper Saddle River, NJ, 1997 [12] Konstantaras A., Varley M.R., Vallianatos F., Collins G. and Holifield P.: ‘Detection of weak seismo-electric signals upon the recordings of the electrotelluric field by means of neuron-fuzzy technology', IEEE Geoscience and Remote Sensing Letters, vol. 4 (1), 2007 [13] Konstantaras A., Varley M.R., Vallianatos F., Collins G. and Holifield P.: ‘Neuro-fuzzy prediction-based adaptive filtering applied to severely distorted magnetic field recordings', IEEE Geoscience and Remote Sensing Letters, vol. 3 (4), 2006 [14] Maravelakis E., Bilalis N., Keith J. and Antoniadis A.: ‘Measuring and Benchmarking the Innovativene

  17. Spatio-temporal patterns of schistosomiasis japonica in lake and marshland areas in China: the effect of snail habitats.

    PubMed

    Hu, Yi; Gao, Jie; Chi, Meina; Luo, Can; Lynn, Henry; Sun, Liqian; Tao, Bo; Wang, Decheng; Zhang, Zhijie; Jiang, Qingwu

    2014-09-01

    The progress of the integrated control policy for schistosomiasis implemented since 2005 in China, which is aiming at reducing the roles of bovines and humans as infection sources, may be challenged by persistent presence of infected snails in lake and marshland areas. Based on annual parasitologic data for schistosomiasis during 2004-2011 in Xingzi County, a spatio-temporal kriging model was used to investigate the spatio-temporal pattern of schistosomiasis risk. Results showed that environmental factors related to snail habitats can explain the spatio-temporal variation of schistosomiasis. Predictive maps of schistosomiasis risk illustrated that clusters of the disease fluctuated during 2004-2008; there was an extensive outbreak in 2008 and attenuated disease occurrences afterwards. An area with an annually constant cluster of schistosomiasis was identified. Our study suggests that targeting snail habitats located within high-risk areas for schistosomiasis would be an economic and sustainable way of schistosomiasis control in the future. PMID:24980498

  18. Multivariate data-driven modelling and pattern recognition for damage detection and identification for acoustic emission and acousto-ultrasonics

    NASA Astrophysics Data System (ADS)

    Torres-Arredondo, M.-A.; Tibaduiza, D.-A.; McGugan, M.; Toftegaard, H.; Borum, K.-K.; Mujica, L. E.; Rodellar, J.; Fritzen, C.-P.

    2013-10-01

    Different methods are commonly used for non-destructive testing in structures; among others, acoustic emission and ultrasonic inspections are widely used to assess structures. The research presented in this paper is motivated by the need to improve the inspection capabilities and reliability of structural health monitoring (SHM) systems based on ultrasonic guided waves with focus on the acoustic emission and acousto-ultrasonics techniques. The use of a guided wave based approach is driven by the fact that these waves are able to propagate over relatively long distances, and interact sensitively and uniquely with different types of defect. Special attention is paid here to the development of efficient SHM methodologies. This requires robust signal processing techniques for the correct interpretation of the complex ultrasonic waves. Therefore, a variety of existing algorithms for signal processing and pattern recognition are evaluated and integrated into the different proposed methodologies. As a contribution to solve the problem, this paper presents results in damage detection and classification using a methodology based on hierarchical nonlinear principal component analysis, square prediction measurements and self-organizing maps, which are applied to data from acoustic emission tests and acousto-ultrasonic inspections. At the end, the efficiency of these methodologies is experimentally evaluated in diverse anisotropic composite structures.

  19. Spatial and temporal variability of plankton stocks from acoustic backscatter intensity and direct measurements in the northeastern Gulf of Mexico

    E-print Network

    Scott, Rebecca Lee

    2001-01-01

    of the zooplankton tows (one hour prior to tow and one hour after tow). A regression analysis was performed using a total of 21 backscatter/zooplankton data pairs. Figure 8 displays the results of the regression analysis between acoustic backscatter intensity... bm at l l ADCP moonng locations. 33 5 Statistically sigmficant correlations (r values) between 40-hour low-pass filtered acoustic backscatter intensity data and 40-hour low-pass filtered rotated current velocity components...

  20. Using Conditional Analysis to Investigate Spatial and Temporal patterns in Upland Rainfall

    NASA Astrophysics Data System (ADS)

    Sakamoto Ferranti, Emma Jayne; Whyatt, James Duncan; Timmis, Roger James

    2010-05-01

    The seasonality and characteristics of rainfall in the UK are altering under a changing climate. Summer rainfall is generally decreasing whereas winter rainfall is increasing, particularly in northern and western areas (Maraun et al., 2008) and recent research suggests these rainfall increases are amplified in upland areas (Burt and Ferranti, 2010). Conditional analysis has been used to investigate these rainfall patterns in Cumbria, an upland area in northwest England. Cumbria was selected as an example of a topographically diverse mid-latitude region that has a predominately maritime and westerly-defined climate. Moreover it has a dense network of more than 400 rain gauges that have operated for periods between 1900 and present day. Cumbria has experienced unprecedented flooding in the past decade and understanding the spatial and temporal changes in this and other upland regions is important for water resource and ecosystem management. The conditional analysis method examines the spatial and temporal variations in rainfall under different synoptic conditions and in different geographic sub-regions (Ferranti et al., 2009). A daily synoptic typing scheme, the Lamb Weather Catalogue, was applied to classify rainfall into different weather types, for example: south-westerly, westerly, easterly or cyclonic. Topographic descriptors developed using GIS were used to classify rain gauges into 6 directionally-dependant geographic sub-regions: coastal, windward-lowland, windward-upland, leeward-upland, leeward-lowland, secondary upland. Combining these classification methods enabled seasonal rainfall climatologies to be produced for specific weather types and sub-regions. Winter rainfall climatologies were constructed for all 6 sub-regions for 3 weather types - south-westerly (SW), westerly (W), and cyclonic (C); these weather types contribute more than 50% of total winter rainfall. The frequency of wet-days (>0.3mm), the total winter rainfall and the average wet day rainfall amount were analysed for each rainfall sub-region and weather type from 1961-2007 (Ferranti et al., 2010). The conditional analysis showed total rainfall under SW and W weather types to be increasing, with the greatest increases observed in the upland sub-regions. The increase in total SW rainfall is driven by a greater occurrence of SW rain days, and there has been little change to the average wet-day rainfall amount. The increase in total W rainfall is driven in part by an increase in the frequency of wet-days, but more significantly by an increase in the average wet-day rainfall amount. In contrast, total rainfall under C weather types has decreased. Further analysis will investigate how spring, summer and autumn rainfall climatologies have changed for the different weather types and sub-regions. Conditional analysis that combines GIS and synoptic climatology provides greater insights into the processes underlying readily available meteorological data. Dissecting Cumbrian rainfall data under different synoptic and geographic conditions showed the observed changes in winter rainfall are not uniform for the different weather types, nor for the different geographic sub-regions. These intricate details are often lost during coarser resolution analysis, and conditional analysis will provide a detailed synopsis of Cumbrian rainfall processes against which Regional Climate Model (RCM) performance can be tested. Conventionally RCMs try to simulate composite rainfall over many different weather types and sub-regions and by undertaking conditional validation the model performance for individual processes can be tested. This will help to target improvements in model performance, and ultimately lead to better simulation of rainfall in areas of complex topography. BURT, T. P. & FERRANTI, E. J. S. (2010) Changing patterns of heavy rainfall in upland areas: a case study from northern England. Atmospheric Environment, [in review]. FERRANTI, E. J. S., WHYATT, J. D. & TIMMIS, R. J. (2009) Development and application of topographic descriptors for conditional a

  1. Temporal and spatial paleoproductivity patterns associated with Eastern Mediterranean sapropels: paleoceanographic significance.

    NASA Astrophysics Data System (ADS)

    Gallego-Torres, D.; Martinez-Ruiz, F.; Meyers, P. A.; Paytan, A.; Jimenez-Espejo, F. J.; Ortega-Huertas, M.

    2007-12-01

    Deposition of Eastern Mediterranean sapropels has been discussed in terms of enhanced primary productivity and/or preferential preservation due to anoxic conditions in the deep basin. However, formation of these organic enriched layers is not homogeneous across the basin and through time, and temporal and spatial patterns can be observed in organic carbon concentrations and depositional conditions. We used a transect of ODP sites in the Eastern Mediterranean for the study of such variations, covering the area of major influence of the European continent and incoming waters from the Western Mediterranean basin (Ionian basin, Site 964), a region of influence of the Nile River (Levantine basin, Site 967), the central region of the basin with minor continental influence (Mediterranean Ridge, Site 969), and shallower bathymetries (Eratosthenes Seamount, Site 966). A set of paleoproductivity related proxies has been applied in order to reconstruct the paleoceanographic conditions that led to the formation of sapropels. As a whole, sapropel formation corresponds to wetter periods occurring during precessional minima and appears associated to increased productivity, evidenced by Ba/Al, and TOC-Ba mass accumulation rates maxima. ?13C data indicate intensified carbon fixation during organic carbon entrapment in sediment, where as low ?15N values provide evidence of nitrogen fixation through cyanobacteria activity as a source of increased primary and export productivity. This overwhelming export productivity led to the depletion of deep water dissolved oxygen, thus improving organic matter preservation. The above mentioned proxies show that sapropels represent periods of high productivity in an otherwise oligotrophic basin. This productivity was initiated and sustained by a change in bacterial community to nitrogen-fixing organism favored by intensified continental drainage and nutrient input. In agreement to this observation, sapropel onset generally occurred earlier in the Levantine basin, directly influenced by variations in the Nile River discharge, and progressively spread toward the western part of the basin. Thus, this change in paleoceanographic conditions is ultimately climatically driven and the evolution of the regional climate affects the intensity of the sapropel formation for the last 3 My. Intensified productivity and enhanced preservation is observed during sapropel deposition from the middle Pliocene until the lower Pleistocene. Productivity maxima occur during the late Pleistocene, coinciding with highest recorded sedimentary rate, and a relatively weak increase is observed during the deposition of the Holocene sapropel. This pattern implies that the rates of deep-water ventilation and of continental erosion generally increased in the eastern Mediterranean region as climate cooled since the mid-Pliocene.

  2. Spatial and Temporal Patterns of On-Road Diesel Truck Emissions in California

    NASA Astrophysics Data System (ADS)

    McDonald, B.; Harley, R. A.

    2011-12-01

    Heavy-duty diesel-powered trucks comprise a relatively small fraction of total traffic, typically less than 10% nationally. However, as light-duty gasoline vehicle emissions have been controlled over time, diesel trucks have become a major source of emissions of pollutants such as nitrogen oxides (NOx) and fine particulate matter (PM). In the past, spatially resolved emission inventories for trucks have often been mapped either by (1) assuming a constant truck fraction and applying that value to gridded estimates of total vehicle miles traveled throughout the area of interest, or (2) using surrogates (e.g., miles of highway available in each grid square) to apportion top-down estimates of diesel emissions. Unfortunately, such simplified descriptions of truck traffic are inaccurate. Goods movement-related traffic differs markedly from passenger vehicle travel in many ways, and truck traffic does not make equal use of all available highways. Here we develop new inventories that reflect observed spatial patterns and day of week, seasonal, and decadal changes in diesel truck emissions. High-resolution (4 km) gridded emission inventories have been developed in this study for diesel trucks in California. Fuel consumption and associated CO2 emissions were calculated for each segment of highway from census counts of truck traffic that span the entire highway network. This captures the majority of truck travel and on-road diesel fuel consumption in California. Remaining truck traffic on other roadways (e.g., urban arterials) is estimated by difference using statewide taxable diesel fuel sales and fuel economy survey data. Fuel-based emission factors measured in roadside remote sensing and tunnel studies were applied to CO2 emissions to estimate NOx. Air basin-specific temporal patterns in diesel truck activity and emissions are derived from 75 Weigh-in-Motion (WIM) traffic count sites located on major highways throughout the state. WIM sensors count and classify vehicles by number of axles and weight per axle, so separate counts for truck traffic are available with hourly or better time resolution. We find strong weekly cycles in diesel truck emissions, with lower values on weekends, especially in urban air basins surrounding Los Angeles and San Francisco. We also find seasonal cycles, up to +/-20% about annual average values, in the San Francisco Bay area and the San Joaquin and Sacramento Valleys. Peak emissions in these areas occur in June-July and appear to be associated with the harvest season in Central California.

  3. [Temporal and spatial pattern of phytoplankton community and its biodiversity indices in the Danjiangkou Reservoir].

    PubMed

    Tan, Xiang; Xia, Xiao-Ling; Cheng, Xiao-Li; Zhang, Quan-Fa

    2011-10-01

    Temporal and spatial patterns of phytoplankton community and their associated influencing factors using canonical correspondence analysis (CCA) were analyzed in the Danjiangkou Reservoir, China. Water quality of the reservoir was also assessed using phytoplankton cell density and biodiversity indices. Results showed that Bacillariophyta and Cyanophyta accounted for 51.08% and 18.39% of all the species, respectively. There was great seasonal variation in phytoplankton assemblage composition, cell density and biodiversity index. In summer, Cyanophyta was dominant and composed of 42.24% of the phytoplankton composition, whereas Bacillariophyta was dominant in spring, summer and winter, and accounted for 77.13%, 61.29% and 50.91% of all species, respectively. The phytoplankton density reached the maximum of 1.76 x 10(6) cells/L in summer, while the lowest value was 2.32 x 10(5) cells/L in autumn. Seasonal variability was the same for the indices of Shannon-Wiener, Simpson and Pielou, and they were 2.08, 0.77, 0.65 in autumn, and decreased to 0.85, 0.32, 0.28 in winter, respectively. Though the spatial variability was not significant in indices H', D, D(m) and J, the difference was significant between the Dan and the Han Reservoirs in terms of phytoplankton composition. The dominant phytoplankton was Bacillariophyta in Dan Reservoir and Cyanophyta in Han Reservoir. The results also indicated that conductivity was the main environmental factor influencing variation in phytoplankton composition except in autumn. The reservoir could be classified as oligotrophication by cell density and the middle level between beta-mesosaprobic zone and oligosaprobic zone using biodiversity indices. The research demonstrated the potential to use phytoplankton community and its biodiversity indices to monitor water quality in the Danjingkou Reservoir. PMID:22279895

  4. Spatial and Temporal Patterns of Soil Organic Carbon in Mangrove Forest Ecosystems (Invited)

    NASA Astrophysics Data System (ADS)

    McKee, K. L.

    2010-12-01

    Wetlands are recognized as potentially important carbon sinks, but few studies have focused on tropical and sub-tropical systems that accumulate organic carbon. Soil organic carbon (SOC) density was analyzed in multiple mangrove forests, representing 30 geographic locations and six forest types (total of 230 study plots overall). SOC density varied from 0.002 to 0.1 g cm-3, with an overall average of 0.019 and 0.058 g cm-3 in mineral and organic soils, respectively. Sites spanned a latitudinal range from 37° S to 29° N, and carbon density was correlated with average annual temperature. However, high variation in SOC density within latitude indicated additional influences. At a regional scale, SOC density varied with forest type and generally increased with hydrologic energy. At a site in Panama, SOC density varied spatially with soil pore space, which influenced bulk density and soil temperature—indicating an influence of compaction and/or degree of decomposition. Carbon sequestration rates estimated from surface accretion of organic C were similar in organic (216 g C m-2 yr-1) and mineral (145 g C m-2 yr-1) soil types, but varied across geographic locations (41 to 591 g C m-2 yr-1). Subsurface inputs of carbon, which were estimated using measured rates of root matter accumulation and root carbon content, averaged 121 g m-2 yr-1, but exceeded 400 g m-2 yr-1 at several sites. Depths of mangrove peat varied across sites from < 1 m to over 10 m, indicating the potentially large carbon stores that can develop under certain conditions. Rates of carbon accretion at a site in Belize have varied from 90 to 300 g C m-2 yr-1 over 8000 yr. These patterns indicate spatial and temporal variability in SOC and suggest multiple controls on rates of carbon accumulation in mangrove ecosystems.

  5. Dynamic Triggering of Microseismicity inferred from Spatio/Temporal Patterns in a Mine Setting

    NASA Astrophysics Data System (ADS)

    Castellanos, F.; Van der Baan, M.

    2014-12-01

    We examine spatial and temporal patterns of microseismic events in an underground mine. Our objective is to address three key questions: Where does the seismicity occur? Why does it occur in these locations but not elsewhere? And what triggers it? We take advantage of waveform similarity by performing multiplet analysis based on the double-difference technique to obtain highly accurate relative locations. Seven vertical receiver boreholes that surround the area under investigation have recorded microseismic data during a month, thus providing a good azimuthal coverage. A minimum crosscorrelation level of 85% is used to detect 21 multiplet groups, which represents 60% of the total seismicity. The largest groups are located close to the main shaft and tunnels at orebody levels, thus we postulate seismicity is facilitated by the potential of subsidence if we assume a compacting earth and hoop stresses acting on the vertical shafts. Surprisingly, most events only occur during certain hours of the day but do not relate to blasting. They correlate with scheduled operations of rock removal. Therefore, it is likely they have been triggered by the transportation of the debris along the main shaft instead of blasting, as we initially expected. Given that seismicity is present around the main shaft but absent close to the second air shaft, we conclude that for seismicity to occur both a favourable stress state must exist, as well as additional external forces, causing dynamic triggering. This analysis provides more insight into anthropogenic processes and their roles as major initiators of seismicity during dynamic stress transfer thereby facilitating identification of hazardous areas in mine settings.

  6. Temporal pattern of accelerated lung growth after tracheal occlusion in the fetal rabbit.

    PubMed

    De Paepe, M E; Johnson, B D; Papadakis, K; Sueishi, K; Luks, F I

    1998-01-01

    Tracheal occlusion in utero is a potent stimulus of fetal lung growth. We describe the early growth mechanics of fetal lungs and type II pneumocytes after tracheal ligation (TL). Fetal rabbits underwent TL at 24 days gestational age (DGA; late pseudoglandular stage; term = 31 to 33 days) and were sacrificed at time intervals ranging from 1 to 5 days after TL. Lung growth was measured by stereological volumetry and bromodeoxyuridine (BrdU) pulse labeling. Pneumocyte II population kinetics were analyzed using a combination of anti-surfactant protein A and BrdU immunohistochemistry and computer-assisted morphometry. Nonoperated littermates served as controls. TL resulted in dramatically enhanced lung growth (lung weight/body weight was 5.00 +/- 0.81% in TL versus 2.52 +/- 0.13% in controls at 29 DGA; P < 0.001, unpaired Student's t-test). Post-TL lung growth was characterized by a 3-day lag-phase typified by relative stagnation of growth, followed by distension of airspaces, increased cell proliferation, and accelerated architectural and cellular maturation by postligation days 4 and 5. During the proliferation phase, the replicative activity of type II cells was markedly increased (type II cell BrdU labeling index was 10.0 +/- 4.1% in TL versus 1.1 +/- 0.3% for controls at 29 DGA; P < 0.02), but their numerical density decreased (3.0 +/- 0.5 x 10(-3)/microm2 in TL versus 4.5 +/- 0.3 x 10(-3)/microm2 in controls at 29 DGA; P < 0.02), suggesting accelerated terminal differentiation to type I cells. In conclusion, post-TL lung development is characterized by a well defined temporal pattern of lung growth and maturation. The rabbit model lends itself well to study the regulatory mechanisms underlying accelerated fetal lung growth after TL. PMID:9422535

  7. Nest site attributes and temporal patterns of northern flicker nest loss: effects of predation and competition.

    PubMed

    Fisher, Ryan J; Wiebe, Karen L

    2006-04-01

    To date, most studies of nest site selection have failed to take into account more than one source of nest loss (or have combined all sources in one analysis) when examining nest site characteristics, leaving us with an incomplete understanding of the potential trade-offs that individuals may face when selecting a nest site. Our objectives were to determine whether northern flickers (Colaptes auratus) may experience a trade-off in nest site selection in response to mammalian nest predation and nest loss to a cavity nest competitor (European starling, Sturnus vulgaris). We also document within-season temporal patterns of these two sources of nest loss with the hypothesis that flickers may also be constrained in the timing of reproduction under both predatory and competitive influence. Mammalian predators frequently depredated flicker nests that were: lower to the ground, less concealed by vegetation around the cavity entrance and at the base of the nest tree, closer to coniferous forest edges and in forest clumps with a high percentage of conifer content. Proximity to coniferous edges or coniferous trees increased the probability of nest predation, but nests near conifers were less likely to be lost to starlings. Flickers may thus face a trade-off in nest site selection with respect to safety from predators or competitors. Models suggested that peaks of nest predation and nest loss to eviction occurred at the same time, although a competing model suggested that the peak of nest loss to starlings occurred 5 days earlier than the peak of mammalian predation. Differences in peaks of mammalian predation and loss to starlings may constrain any adjustment in clutch initiation date by flickers to avoid one source of nest loss. PMID:16323016

  8. Temporal patterns of nitrogen leakage from mid-Appalachian forested watersheds: Role of insect defoliation

    NASA Astrophysics Data System (ADS)

    Eshleman, Keith N.; Morgan, Raymond P.; Webb, James R.; Deviney, Frank A.; Galloway, James N.

    1998-08-01

    Fluxes of dissolved nitrogen (N) as nitrate from forested watersheds in the mid-Appalachian region have important water quality ramifications for small acid-sensitive streams and for downstream receiving waters such as the Chesapeake Bay. Previous studies of N leakage have suggested that annual dissolved N fluxes from small watersheds can vary by several orders of magnitude and may be increasing as second-growth forests gradually become N saturated from the accrual of atmospheric N loadings. In this study, we examined the temporal (intra-annual and interannual) variability in dissolved nitrate fluxes from five small (area < 15 km2) forested watersheds in the mid-Appalachian region from 1988 to 1995. At all sites, nitrate concentrations were observed to increase dramatically during storm flow events, with nitric acid contributing significantly to depressions in pH and acid-neutralizing capacity; annual nitrate fluxes were dominated by high-discharge periods. Interannually, the fluxes at each site varied by 1-2 orders of magnitude, but the patterns of N leakage displayed considerable synchrony with outbreaks of gypsy moth caterpillar defoliation that began in the late 1980s and early 1990s in this region. N leakage from forested watersheds apparently lagged the initial defoliation by several months to perhaps a year or more. Defoliation outbreaks by the gypsy moth caterpillar (or other herbivorous pests) thus provide an alternative explanation of N leakage from forest ecosystems. Poorly documented insect defoliations, rather than premature N saturation of intact forest ecosystems, need to be considered as a possible explanation of N leakage from forested watersheds in the mid-Appalachian region and elsewhere.

  9. A GIS-based Bayesian approach for analyzing spatial–temporal patterns of intra-city motor vehicle crashes

    Microsoft Academic Search

    Linhua Li; Li Zhu; Daniel Z. Sui

    2007-01-01

    This paper develops a GIS-based Bayesian approach for intra-city motor vehicle crash analysis. Five-year crash data for Harris County (primarily the City of Houston), Texas are analyzed using a geographic information system (GIS), and spatial–temporal patterns of relative crash risks are identified based on a Bayesian approach. This approach is used to identify and rank roadway segments with potentially high

  10. GATA5: A Transcriptional Activator Expressed in a Novel Temporally and Spatially-Restricted Pattern during Embryonic Development

    Microsoft Academic Search

    Edward E. Morrisey; Hon S. Ip; Zhihua Tang; Min M. Lu; Michael S. Parmacek

    1997-01-01

    Members of the GATA family of zinc finger transcription factors regulate critical steps of cellular differentiation during vertebrate development. In the studies described in this report, we have isolated and functionally characterized the murine GATA-5 cDNA and protein and defined the temporal and spatial pattern of GATA-5 gene expression during mammalian development. The amino terminus of the mouse GATA-5 protein

  11. Acoustic measurements of the spatial and temporal structure of the near-bottom boundary layer in the 1990-1991 STRESS experiment

    NASA Astrophysics Data System (ADS)

    Lynch, James F.; Irish, James D.; Gross, Thomas F.; Wiberg, Patricia L.; Newhall, Arthur E.; Traykovski, Peter A.; Warren, Joseph D.

    1997-08-01

    As part of the 1990-1991 Sediment TRansport Events on Shelves and Slopes (STRESS) experiment, a 5 MHz Acoustic BackScatter System (ABSS) was deployed in 90 m of water to measure vertical profiles of near-bottom suspended sediment concentration. By looking at the vertical profile of concentration from 0 to 50 cm above bottom (cmab) with 1 cm vertical resolution, the ABSS was able to examine the detailed structure of the bottom boundary layer created by combined wave and current stresses. The acoustic profiles clearly showed the wave-current boundary layer, which extends to (order) 10 cmab. The profiles also showed evidence of an "intermediate" boundary layer, also influenced by combined wave and current stresses, just above the wave-current boundary layer. This paper examines the boundary-layer structure by comparing acoustic data obtained by the authors to a 1-D eddy viscosity model formulation. Specifically, these data are compared to a simple extension of the Grant-Glenn-Madsen model formulation. Also of interest is the appearance of apparently 3-D "advective plume" structures in these data. This is an interesting feature in a site which was initially chosen to be a good example of (temporally averaged) 1-D bottom boundary-layer dynamics. Computer modeling and sector-scanning sonar images are presented to justify the plausibility of observing 3-D structure at the STRESS site. 1997 Elsevier Science Ltd

  12. Temporal stability of estimated soil water flux patterns across agricultural fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When a field or a small watershed is repeatedly surveyed for soil water content, sites often can be spotted where soil is consistently wetter or consistently dryer than average across the study area. This phenomenon has been called time stability, temporal stability, temporal persistence, or rank st...

  13. Dynamic maps: a visual-analytic methodology for exploring spatio-temporal disease patterns

    Microsoft Academic Search

    Denise A Castronovo; Kenneth KH Chui; Elena N Naumova

    2009-01-01

    BACKGROUND: Epidemiologic studies are often confounded by the human and environmental interactions that are complex and dynamic spatio-temporal processes. Hence, it is difficult to discover nuances in the data and generate pertinent hypotheses. Dynamic mapping, a method to simultaneously visualize temporal and spatial information, was introduced to elucidate such complexities. A conceptual framework for dynamic mapping regarding principles and implementation

  14. SN algorithm: analysis of temporal clinical data for mining periodic patterns and impending augury

    PubMed Central

    2013-01-01

    Background EHR (Electronic Health Record) system has led to development of specialized form of clinical databases which enable storage of information in temporal prospective. It has been a big challenge for mining this form of clinical data considering varied temporal points. This study proposes a conjoined solution to analyze the clinical parameters akin to a disease. We have used “association rule mining algorithm” to discover association rules among clinical parameters that can be augmented with the disease. Furthermore, we have proposed a new algorithm, SN algorithm, to map clinical parameters along with a disease state at various temporal points. Result SN algorithm is based on Jacobian approach, which augurs the state of a disease ‘Sn’ at a given temporal point ‘Tn’ by mapping the derivatives with the temporal point ‘T0’, whose state of disease ‘S0’ is known. The predictive ability of the proposed algorithm is evaluated in a temporal clinical data set of brain tumor patients. We have obtained a very high prediction accuracy of ~97% for a brain tumor state ‘Sn’ for any temporal point ‘Tn’. Conclusion The results indicate that the methodology followed may be of good value to the diagnostic procedure, especially for analyzing temporal form of clinical data. PMID:24283349

  15. CLASSIFICATION OF FOOD KERNELS WITH IMPACT ACOUSTICS TIME-1 FREQUENCY PATTERNS2

    E-print Network

    Minnesota, University of

    13 signals for detecting hazelnuts with cracked shells and damaged wheat kernels. The impact acoustic surface so it31 is nearly impossible to detect by visual inspection. When the egg hatches, the insect%, 82% and22 94%, respectively. For the cracked undamaged shell hazelnut separation, the overall

  16. Acoustic Modal Patterns and Striations (AMPS) experiment G-325, Norfolk Public Schools

    NASA Technical Reports Server (NTRS)

    Young, Joy W.

    1995-01-01

    This paper will describe how high school students with the guidance of volunteer mentors were able to successfully complete an acoustics space experiment. Some of the NORSTAR program strategies used to effectively accomplish this goal will be discussed. The experiment and present status of results will be explained.

  17. Automated pattern analysis: A newsilent partner in insect acoustic detection studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This seminar reviews methods that have been developed for automated analysis of field-collected sounds used to estimate pest populations and guide insect pest management decisions. Several examples are presented of successful usage of acoustic technology to map insect distributions in field environ...

  18. Spatial and temporal patterns of larval dispersal in a coral-reef fish metapopulation: evidence of variable reproductive success.

    PubMed

    Pusack, Timothy J; Christie, Mark R; Johnson, Darren W; Stallings, Christopher D; Hixon, Mark A

    2014-07-01

    Many marine organisms can be transported hundreds of kilometres during their pelagic larval stage, yet little is known about spatial and temporal patterns of larval dispersal. Although traditional population-genetic tools can be applied to infer movement of larvae on an evolutionary timescale, large effective population sizes and high rates of gene flow present serious challenges to documenting dispersal patterns over shorter, ecologically relevant, timescales. Here, we address these challenges by combining direct parentage analysis and indirect genetic analyses over a 4-year period to document spatial and temporal patterns of larval dispersal in a common coral-reef fish: the bicolour damselfish (Stegastes partitus). At four island locations surrounding Exuma Sound, Bahamas, including a long-established marine reserve, we collected 3278 individuals and genotyped them at 10 microsatellite loci. Using Bayesian parentage analysis, we identified eight parent-offspring pairs, thereby directly documenting dispersal distances ranging from 0 km (i.e., self-recruitment) to 129 km (i.e., larval connectivity). Despite documenting substantial dispersal and gene flow between islands, we observed more self-recruitment events than expected if the larvae were drawn from a common, well-mixed pool (i.e., a completely open population). Additionally, we detected both spatial and temporal variation in signatures of sweepstakes and Wahlund effects. The high variance in reproductive success (i.e., 'sweepstakes') we observed may be influenced by seasonal mesoscale gyres present in the Exuma Sound, which play a prominent role in shaping local oceanographic patterns. This study documents the complex nature of larval dispersal in a coral-reef fish, and highlights the importance of sampling multiple cohorts and coupling both direct and indirect genetic methods in order disentangle patterns of dispersal, gene flow and variable reproductive success. PMID:24917250

  19. Cascadia Segmentation and Long Term Temporal Rupture Pattern based on Paleoseismicity: some Global Implications

    NASA Astrophysics Data System (ADS)

    Goldfinger, C.

    2011-12-01

    Onshore and offshore paleoseismic evidence from 41 Cascadia earthquakes strongly suggest that segmentation plays a significant role in Cascadia, and may have multiple sources. Offshore turbidite records show a remarkable correspondence along strike in 14C ages, physical property correlations, and even details such as mass per event and number of coarse fraction units per event. The joint correlation of these parameters allows approximate delineation of paleo-rupture extent, limited mostly by the spatial distribution of cores. The onshore-offshore space-time diagram reveals that recurrence intervals and segment length decreases southward along the margin. Southern segments may be controlled by obvious structural boundaries such as the Blanco Fracture zone, and two subducting pseudo faults. Along the northern margin, where segmentation is not apparent, basement structure is masked by thicker incoming sediment supply from two large fan systems, supporting a primary control by sediment thickness on the subducting plate. We suspect, supported by paleoseismic data, that northern Cascadia and northern Sumatra may be prone to large ruptures by similar mechanisms. One segment boundary in Cascadia appears not to be related to sediment supply, but may linked to a narrowing of the locked interface in map view. The Cascadia forearc is composed of an Eocene-Pliocene accretionary complex, outboard of which lies a Pleistocene-Holocene wedge of low taper, mixed vergence, and high pore fluid pressure. The young wedge is widest off Washington and northernmost Oregon, tapering both north and south. Mixed vergence, open folds, mud volcanoes and backstop parallel trends indicate poor coupling of the young wedge that is easily mapped from surface data. The long-term average downdip limit of significant coupling appears to be consistent with thermal, geodetic, and structural evidence of a transition from arc normal to arc parallel contraction. An average boundary consistent with these disparate data suggest significant heterogeneity in along-strike width and or magnitude of coupling. A seaward swing of the downdip locked zone, combined with a landward position of the updip limit may create a "pinchout" in central Oregon, where we observe a paleoseismic segment boundary. The 10ka paleoseismic record includes evidence of temporal variability as well. Temporal clustering, and the presence of several outsized events is apparent. When we compare the mass of correlated turbidite deposits along strike, we find a surprisingly strong correspondence between disparate sites, enough to conclude that earthquake magnitude and turbidite mass are crudely related for many Cascadia events. The two outsized events, dated at ~ 5960 and 8810 yrs. BP, consistently have two to five times the average turbidite mass for Holocene events at many sites, a relation not related to sediment supply. Plotting the long term energy balance based on mass per event reveals a robust pattern including long term increases and declines in stored "energy state" or "supercycles". If Cascadia is representative of other plate boundary faults, this suggests that recurrence models may be neither time nor slip predictable and cannot be based on short instrumental records.

  20. Spatio-temporal Patterns and Landscape-Associated Risk of Buruli Ulcer in Akonolinga, Cameroon

    PubMed Central

    Landier, Jordi; Gaudart, Jean; Carolan, Kevin; Lo Seen, Danny; Guégan, Jean-François; Eyangoh, Sara; Fontanet, Arnaud; Texier, Gaëtan

    2014-01-01

    Background Buruli ulcer (BU) is an extensively damaging skin infection caused by Mycobacterium ulcerans, whose transmission mode is still unknown. The focal distribution of BU and the absence of interpersonal transmission suggest a major role of environmental factors, which remain unidentified. This study provides the first description of the spatio-temporal variations of BU in an endemic African region, in Akonolinga, Cameroon. We quantify landscape-associated risk of BU, and reveal local patterns of endemicity. Methodology/Principal Findings From January 2002 to May 2012, 787 new BU cases were recorded in 154 villages of the district of Akonolinga. Incidence per village ranged from 0 (n?=?59 villages) to 10.4 cases/1000 person.years (py); median incidence was 0.4 cases/1,000py. Villages neighbouring the Nyong River flood plain near Akonolinga town were identified as the highest risk zone using the SPODT algorithm. We found a decreasing risk with increasing distance to the Nyong and identified 4 time phases with changes in spatial distribution. We classified the villages into 8 groups according to landscape characteristics using principal component analysis and hierarchical clustering. We estimated the incidence ratio (IR) associated with each landscape using a generalised linear model. BU risk was highest in landscapes with abundant wetlands, especially cultivated ones (IR?=?15.7, 95% confidence interval [95%CI]?=?15.7[4.2–59.2]), and lowest in reference landscape where primary and secondary forest cover was abundant. In intermediate-risk landscapes, risk decreased with agriculture pressure (from IR[95%CI]?=?7.9[2.2–28.8] to 2.0[0.6–6.6]). We identified landscapes where endemicity was stable and landscapes where incidence increased with time. Conclusion/Significance Our study on the largest series of BU cases recorded in a single endemic region illustrates the local evolution of BU and identifies the Nyong River as the major driver of BU incidence. Local differences along the river are explained by wetland abundance and human modification of the environment. PMID:25188464

  1. Incorporation of treatment plan spatial and temporal dose patterns into a prostate intrafractional motion management strategy

    SciTech Connect

    Zhang Pengpeng; Hunt, Margie; Happersett, Laura; Cox, Brett; Mageras, Gig [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States); Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States)

    2012-09-15

    Purpose: Periodic MV/KV radiographs taken during volumetric modulated arc therapy (VMAT) for hypofractionated treatment provide guidance in intrafractional motion management. The choice of imaging frequency and timing are key components in delivering the desired dose while reducing associated overhead such as imaging dose, preparation, and processing time. In this project the authors propose a paradigm with imaging timing and frequency based on the spatial and temporal dose patterns of the treatment plan. Methods: A number of control points are used in treatment planning to model VMAT delivery. For each control point, the sensitivity of individual target or organ-at-risk dose to motion can be calculated as the summation of dose degradations given the organ displacements along a number of possible motion directions. Instead of acquiring radiographs at uniform time intervals, MV/KV image pairs are acquired indexed to motion sensitivity. Five prostate patients treated via hypofractionated VMAT are included in this study. Intrafractional prostate motion traces from the database of an electromagnetic tracking system are used to retrospectively simulate the VMAT delivery and motion management. During VMAT delivery simulation patient position is corrected based on the radiographic findings via couch movement if target deviation violates a patient-specific 3D threshold. The violation rate calculated as the percentage of traces failing the clinical dose objectives after motion correction is used to evaluate the efficacy of this approach. Results: Imaging indexed to a 10 s equitime interval and correcting patient position accordingly reduces the violation rate to 19.5% with intervention from 44.5% without intervention. Imaging indexed to the motion sensitivity further reduces the violation rate to 12.1% with the same number of images. To achieve the same 5% violation rate, the imaging incidence can be reduced by 40% by imaging indexed to motion sensitivity instead of time. Conclusions: The simulation results suggest that image scheduling according to the characteristics of the treatment plan can improve the efficiency of intrafractional motion management. Using such a technique, the accuracy of delivered dose during image-guided hypofractionated VMAT treatment can be improved.

  2. Analyzing spatial-temporal patterns of motor vehicle crashes using GIS: a case study in Dallas

    E-print Network

    Lu, Bing

    2003-01-01

    This paper uses GIS to analyze the characteristics of temporal and spatial distributions of motor vehicle crashes. These characteristics include that traffic accidents are most likely to occur in the afternoon "rush hour" (4:00 - 6:00PM...

  3. Representation of interval timing by temporally scalable firing patterns in rat prefrontal cortex

    PubMed Central

    Xu, Min; Zhang, Si-yu; Dan, Yang; Poo, Mu-ming

    2014-01-01

    Perception of time interval on the order of seconds is an essential component of cognition, but the underlying neural mechanism remains largely unknown. In rats trained to estimate time intervals, we found that many neurons in the medial prefrontal cortex (PFC) exhibited sustained spiking activity with diverse temporal profiles of firing-rate modulation during the time-estimation period. Interestingly, in tasks involving different intervals, each neuron exhibited firing-rate modulation with the same profile that was temporally scaled by a factor linearly proportional to the instructed intervals. The behavioral variability across trials within each task also correlated with the intertrial variability of the temporal scaling factor. Local cooling of the medial PFC, which affects neural circuit dynamics, significantly delayed behavioral responses. Thus, PFC neuronal activity contributes to time perception, and temporally scalable firing-rate modulation may reflect a general mechanism for neural representation of interval timing. PMID:24367075

  4. Spatial pattern and temporal dynamics of northern bobwhite abundance and agricultural landuse, and potential casual factors 

    E-print Network

    Okay, Atiye Zeynep

    2006-04-12

    There was a long-term decline in northern bobwhite (Colinus virginianus, NBW) abundance since the 1920s, based on the Christmas Bird Count (CBC) data, but with substantial spatial and temporal variations across its range. ...

  5. Numerical Study of the Complex Temporal Pattern of Spontaneous Oscillation in Bullfrog Saccular Hair Cells

    NASA Astrophysics Data System (ADS)

    Roongthumskul, Yuttana; Fredrickson-Hemsing, Lea; Kao, Albert; Bozovic, Dolores

    2011-11-01

    Hair bundles of the bullfrog sacculus display spontaneous oscillations that show complex temporal profiles. Quiescent intervals are typically interspersed with oscillations, analogous to bursting behavior observed in neural systems. By introducing slow calcium dynamics into the theoretical model of bundle mechanics, we reproduce numerically the multi-mode oscillations and explore the effects of internal parameters on the temporal profiles and the frequency tuning of their linear response functions. We also study the effects of mechanical overstimulation on the oscillatory behavior.

  6. STRUCTURAL INTEGRITY EVALUATION OF WIND TURBINE BLADES USING PATTERN RECOGNITION ANALYSIS ON ACOUSTIC EMISSION DATA

    Microsoft Academic Search

    A. A. Anastassopoulos; D. A. Kouroussis; V. N. Nikolaidis; A. Proust; A. G. Dutton; M. J. Blanch; L. E. Jones; P. Vionis; D. J. Lekou; D R V van Delft; P. A. Joosse

    2002-01-01

    Current Wind Turbine (W\\/T) Blade certification practices require the conduction of static and fatigue tests on new blades, in order to assess whether the blade can sustain the applied loads. Within the scopes of a current EC-funded research project, Acoustic Emission (AE) monitoring has been extensively applied during testing of various W\\/T Blades of similar design. All blades were loaded

  7. Spatial and Temporal Variation in Color Pattern Morphology in the Tropical Frog, Eleutherodactylus coqui

    E-print Network

    and patterns that help to camouflage the animal. Animals that rely on camouflage are generally palatable patterns help to conceal the shape of prey animals and thus can be viewed as a type of camouflage (Owen

  8. Temporal motifs reveal collaboration patterns in online task-oriented networks

    NASA Astrophysics Data System (ADS)

    Xuan, Qi; Fang, Huiting; Fu, Chenbo; Filkov, Vladimir

    2015-05-01

    Real networks feature layers of interactions and complexity. In them, different types of nodes can interact with each other via a variety of events. Examples of this complexity are task-oriented social networks (TOSNs), where teams of people share tasks towards creating a quality artifact, such as academic research papers or software development in commercial or open source environments. Accomplishing those tasks involves both work, e.g., writing the papers or code, and communication, to discuss and coordinate. Taking into account the different types of activities and how they alternate over time can result in much more precise understanding of the TOSNs behaviors and outcomes. That calls for modeling techniques that can accommodate both node and link heterogeneity as well as temporal change. In this paper, we report on methodology for finding temporal motifs in TOSNs, limited to a system of two people and an artifact. We apply the methods to publicly available data of TOSNs from 31 Open Source Software projects. We find that these temporal motifs are enriched in the observed data. When applied to software development outcome, temporal motifs reveal a distinct dependency between collaboration and communication in the code writing process. Moreover, we show that models based on temporal motifs can be used to more precisely relate both individual developer centrality and team cohesion to programmer productivity than models based on aggregated TOSNs.

  9. Temporal Patterns of Ant Diversity across a Mountain with Climatically Contrasting Aspects in the Tropics of Africa

    PubMed Central

    Munyai, Thinandavha Caswell; Foord, Stefan Hendrik

    2015-01-01

    Factors that drive species richness over space and time are still poorly understood and are often context specific. Identifying these drivers for ant diversity has become particularly relevant within the context of contemporary global change events. We report on a long-term bi-annual (wet and dry seasons), standardized sampling of epigeal ants over a five year period on the mesic and arid aspects of an inselberg (Soutpansberg Mountain Range) in the tropics of Africa. We detail seasonal, annual and long-term trends of species density, test the relative contribution of geometric constraints, energy, available area, climate, local environmental variables, time, and space in explaining ant species density patterns through Generalized Linear Mixed Models (GLMM) where replicates were included as random factors to account for temporal pseudo-replication. Seasonal patterns were very variable and we found evidence of decreased seasonal variation in species density with increased elevation. The extent and significance of a decrease in species density with increased elevation varied with season. Annual patterns point to an increase in ant diversity over time. Ant density patterns were positively correlated with mean monthly temperature but geometric constraints dominated model performance while soil characteristics were minor correlates. These drivers and correlates accounted for all the spatio-temporal variability in the database. Ant diversity was therefore mainly determined by geometric constraints and temperature while soil characteristics (clay and carbon content) accounted for smaller but significant amounts of variation. This study documents the role of season, elevation and their interaction in affecting ant species densities while highlighting the importance of neutral processes and temperature in driving these patterns. PMID:25774670

  10. Multi-voxel pattern analysis of selective representation of visual working memory in ventral temporal and occipital regions.

    PubMed

    Han, Xufeng; Berg, Alexander C; Oh, Hwamee; Samaras, Dimitris; Leung, Hoi-Chung

    2013-06-01

    While previous results from univariate analysis showed that the activity level of the parahippocampal gyrus (PHG) but not the fusiform gyrus (FG) reflects selective maintenance of the cued picture category, present results from multi-voxel pattern analysis (MVPA) showed that the spatial response patterns of both regions can be used to differentiate the selected picture category in working memory. The ventral temporal and occipital areas including the PHG and FG have been shown to be specialized in perceiving and processing different kinds of visual information, though their role in the representation of visual working memory remains unclear. To test whether the PHG and FG show spatial response patterns that reflect selective maintenance of task-relevant visual working memory in comparison with other posterior association regions, we reanalyzed data from a previous fMRI study of visual working memory with a cue inserted during the delay period of a delayed recognition task. Classification of FG and PHG activation patterns for the selected category (face or scene) during the cue phase was well above chance using classifiers trained with fMRI data from the cue or probe phase. Classification of activity in other temporal and occipital regions for the cued picture category during the cue phase was relatively less consistent even though classification of their activity during the probe recognition was comparable with the FG and PHG. In sum, these findings suggest that the FG and PHG carry information relevant to the cued visual category, and their spatial activation patterns during selective maintenance seem to match those during visual recognition. PMID:23380167

  11. Assessing hippocampal functional reserve in temporal lobe epilepsy: a multi-voxel pattern analysis of fMRI data.

    PubMed

    Bonnici, Heidi M; Sidhu, Meneka; Chadwick, Martin J; Duncan, John S; Maguire, Eleanor A

    2013-07-01

    Assessing the functional reserve of key memory structures in the medial temporal lobes (MTL) of pre-surgical patients with intractable temporal lobe epilepsy (TLE) remains a challenge. Conventional functional MRI (fMRI) memory paradigms have yet to fully convince of their ability to confidently assess the risk of a post-surgical amnesia. An alternative fMRI analysis method, multi-voxel pattern analysis (MVPA), focuses on the patterns of activity across voxels in specific brain regions that are associated with individual memory traces. This method makes it possible to investigate whether the hippocampus and related structures contralateral to any proposed surgery are capable of laying down and representing specific memories. Here we used MVPA-fMRI to assess the functional integrity of the hippocampi and MTL in patients with long-standing medically refractory TLE associated with unilateral hippocampal sclerosis (HS). Patients were exposed to movie clips of everyday events prior to scanning, which they subsequently recalled during high-resolution fMRI. MTL structures were delineated and pattern classifiers were trained to learn the patterns of brain activity across voxels associated with each memory. Predictable patterns of activity across voxels associated with specific memories could be detected in MTL structures, including the hippocampus, on the side contralateral to the HS, indicating their functional viability. By contrast, no discernible memory representations were apparent in the sclerotic hippocampus, but adjacent MTL regions contained detectable information about the memories. These findings suggest that MVPA in fMRI memory studies of TLE can indicate hippocampal functional reserve and may be useful to predict the effects of hippocampal resection in individual patients. PMID:23352740

  12. Spatial and Temporal Patterns of Locally-Acquired Dengue Transmission in Northern Queensland, Australia, 1993–2012

    PubMed Central

    Naish, Suchithra; Dale, Pat; Mackenzie, John S.; McBride, John; Mengersen, Kerrie; Tong, Shilu

    2014-01-01

    Background Dengue has been a major public health concern in Australia since it re-emerged in Queensland in 1992–1993. We explored spatio-temporal characteristics of locally-acquired dengue cases in northern tropical Queensland, Australia during the period 1993–2012. Methods Locally-acquired notified cases of dengue were collected for northern tropical Queensland from 1993 to 2012. Descriptive spatial and temporal analyses were conducted using geographic information system tools and geostatistical techniques. Results 2,398 locally-acquired dengue cases were recorded in northern tropical Queensland during the study period. The areas affected by the dengue cases exhibited spatial and temporal variation over the study period. Notified cases of dengue occurred more frequently in autumn. Mapping of dengue by statistical local areas (census units) reveals the presence of substantial spatio-temporal variation over time and place. Statistically significant differences in dengue incidence rates among males and females (with more cases in females) (?2?=?15.17, d.f.?=?1, p<0.01). Differences were observed among age groups, but these were not statistically significant. There was a significant positive spatial autocorrelation of dengue incidence for the four sub-periods, with the Moran's I statistic ranging from 0.011 to 0.463 (p<0.01). Semi-variogram analysis and smoothed maps created from interpolation techniques indicate that the pattern of spatial autocorrelation was not homogeneous across the northern Queensland. Conclusions Tropical areas are potential high-risk areas for mosquito-borne diseases such as dengue. This study demonstrated that the locally-acquired dengue cases have exhibited a spatial and temporal variation over the past twenty years in northern tropical Queensland, Australia. Therefore, this study provides an impetus for further investigation of clusters and risk factors in these high-risk areas. PMID:24691549

  13. Temporal control of self-organized pattern formation without morphogen gradients in bacteria

    PubMed Central

    Payne, Stephen; Li, Bochong; Cao, Yangxiaolu; Schaeffer, David; Ryser, Marc D; You, Lingchong

    2013-01-01

    Diverse mechanisms have been proposed to explain biological pattern formation. Regardless of their specific molecular interactions, the majority of these mechanisms require morphogen gradients as the spatial cue, which are either predefined or generated as a part of the patterning process. However, using Escherichia coli programmed by a synthetic gene circuit, we demonstrate here the generation of robust, self-organized ring patterns of gene expression in the absence of an apparent morphogen gradient. Instead of being a spatial cue, the morphogen serves as a timing cue to trigger the formation and maintenance of the ring patterns. The timing mechanism enables the system to sense the domain size of the environment and generate patterns that scale accordingly. Our work defines a novel mechanism of pattern formation that has implications for understanding natural developmental processes. PMID:24104480

  14. Temporal scales of auditory objects underlying birdsong vocal recognition.

    PubMed

    Gentner, Timothy Q

    2008-08-01

    Vocal recognition is common among songbirds, and provides an excellent model system to study the perceptual and neurobiological mechanisms for processing natural vocal communication signals. Male European starlings, a species of songbird, learn to recognize the songs of multiple conspecific males by attending to stereotyped acoustic patterns, and these learned patterns elicit selective neuronal responses in auditory forebrain neurons. The present study investigates the perceptual grouping of spectrotemporal acoustic patterns in starling song at multiple temporal scales. The results show that permutations in sequencing of submotif acoustic features have significant effects on song recognition, and that these effects are specific to songs that comprise learned motifs. The observations suggest that (1) motifs form auditory objects embedded in a hierarchy of acoustic patterns, (2) that object-based song perception emerges without explicit reinforcement, and (3) that multiple temporal scales within the acoustic pattern hierarchy convey information about the individual identity of the singer. The authors discuss the results in the context of auditory object formation and talker recognition. PMID:18681620

  15. On the use of sequential patterns mining as temporal features for music genre classification

    Microsoft Academic Search

    Jia-Min Ren; Zhi-Sheng Chen; Jyh-Shing Roger Jang

    2010-01-01

    Music can be viewed as a sequence of sound events. However, most of current approaches to genre classification either ignore temporal information or only capture local structures within the music under analysis. In this paper, we propose the use of a song tokenization method (which transforms the music into a sequence of units) in conjunction with a data mining technique

  16. An analysis of clinical seizure patterns and their localizing value in frontal and temporal lobe epilepsies

    Microsoft Academic Search

    M. Manford; D. R. Fish; S. D. Shorvon

    1996-01-01

    Summary The differentiation of frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE) is a clinical problem of major theoretical and practical importance. Current electroclinical classification is based on retrospective studies of highly selected patients. When applied to the presurgical evaluation of patients, it has poor specificity. The current study adopts a different and prospective approach to the analysis of

  17. Temporal integration of sequential auditory events: silent period in sound pattern activates human planum temporale

    Microsoft Academic Search

    Henrietta Mustovic; Klaus Scheffler; Francesco Di Salle; Fabrizio Esposito; John G Neuhoff; Jürgen Hennig; Erich Seifritz

    2003-01-01

    Temporal integration is a fundamental process that the brain carries out to construct coherent percepts from serial sensory events. This process critically depends on the formation of memory traces reconciling past with present events and is particularly important in the auditory domain where sensory information is received both serially and in parallel. It has been suggested that buffers for transient

  18. Disentangling temporal patterns in our perception of the fossil history of gymnosperms

    Microsoft Academic Search

    Borja Cascales-Miñana

    2011-01-01

    By taking gymnosperms as a case study, this article evaluates the perception of plant life history from the fossil record to test the biases associated with the time-dependent aspects of the taxonomy, following a stepwise modelling procedure based on two divergent sets of time units. The idea that the effects of the temporal component of paleobiological inference need to be

  19. Disentangling temporal patterns in our perception of the fossil history of gymnosperms

    Microsoft Academic Search

    Borja Cascales-Miñana

    2012-01-01

    By taking gymnosperms as a case study, this article evaluates the perception of plant life history from the fossil record to test the biases associated with the time-dependent aspects of the taxonomy, following a stepwise modelling procedure based on two divergent sets of time units. The idea that the effects of the temporal component of paleobiological inference need to be

  20. Geographical variation in temporal and spatial vocalization patterns of male harbour seals in the mating season

    Microsoft Academic Search

    Sofie M. Van Parijs; Gordon D. Hastie; Paul M. Thompson

    1999-01-01

    In the aquatically mating harbour seal, Phoca vitulina, oestrous females show marked differences in spatial and temporal distribution between geographical areas. This suggests that the males' display behaviour may also vary between areas. We recorded male vocalizations in two areas, the Moray Firth and Orkney, U.K. In the Moray Firth, females haul out on a few intertidal sandbars and travel

  1. Temporal stability of soil water contents as affected by weather patterns: a simulation study.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temporal stability of soil water content (TS SWC) is a natural phenomenon that recently attracts attention and finds multiple applications. Large variations in the interannual and interseasonal TS SWC have been encountered among locations studied by various authors. The objective of this work was ...

  2. Spatial and temporal patterns of cuttlefish (Sepia officinalis) abundance and environmental influences – a case study using trawl fishery data in French Atlantic coastal, English Channel, and adjacent waters

    Microsoft Academic Search

    Jianjun Wang; Graham J. Pierce; Peter R. Boyle; Vincent Denis; Jean-paul Robin; Jose M. Bellido

    2003-01-01

    The spatial and temporal distribution patterns of cuttlefish abundance and the relationships between cuttlefish abundance and environmental variables in the French Atlantic coast, the English Channel, and adjacent waters were studied using both geographical information system and statistical methods. Cuttlefish have a clear general annual migration pattern, consistently occurring in broadly the same areas in different years. The strength of

  3. Complex temporal patterns in molecular dynamics: A direct measure of the phase-space exploration by the trajectory at macroscopic time scales

    E-print Network

    Nerukh, Dmitry

    Complex temporal patterns in molecular dynamics: A direct measure of the phase-space exploration how the trajectory explores the phase space and independent from the particular molecular signal used in liquids form complex patterns in the phase space. Because of the system's high dimensionality defined

  4. Evaluating spatial and temporal patterns of MODIS GPP over the conterminous U.S. against flux measurements and a process model

    E-print Network

    Chen, Jiquan

    Evaluating spatial and temporal patterns of MODIS GPP over the conterminous U.S. against fluxCB) photosynthetic models are widely used for GPP estimation. In this paper, the MODIS GPP algorithm using the LUE them in terms of their spatial and tem- poral distribution patterns. The spatial distribution of MODIS

  5. Spatial and temporal patterns of species diversity in montane mammal communities of western North America

    Microsoft Academic Search

    Elizabeth A. Hadly; Brian A. Maurer

    1996-01-01

    We present the results of the first analysis of distributional patterns of the same taxa across thousands of kilometres and thousands of years, which demonstrate that the exponents for the power relationships in space and time are similar. In both space and time, the distribution of mammalian taxa of the Great Basin and Rocky Mountains follows a 'nested subset' pattern.

  6. Dependence of Empirical Fundamental Diagram on Spatial-Temporal Traffic Patterns Features

    Microsoft Academic Search

    Boris S. Kerner

    2003-01-01

    It is shown that the branch of the empirical fundamental diagram for congested traffic strongly depends both on the type of the congested pattern at a freeway bottleneck and on the freeway location where the fundamental diagram is measured. Since the type of the pattern at the same bottleneck can depend on traffic demand, a qualitative form of the empirical

  7. High resolution acoustic measurement system and beam pattern reconstruction method for bat echolocation emissions.

    PubMed

    Gaudette, Jason E; Kloepper, Laura N; Warnecke, Michaela; Simmons, James A

    2014-01-01

    Measurements of the transmit beam patterns emitted by echolocating bats have previously been limited to cross-sectional planes or averaged over multiple signals using sparse microphone arrays. To date, no high-resolution measurements of individual bat transmit beams have been reported in the literature. Recent studies indicate that bats may change the time-frequency structure of their calls depending on the task, and suggest that their beam patterns are more dynamic than previously thought. To investigate beam pattern dynamics in a variety of bat species, a high-density reconfigurable microphone array was designed and constructed using low-cost ultrasonic microphones and custom electronic circuitry. The planar array is 1.83?m wide by 1.42?m tall with microphones positioned on a 2.54?cm square grid. The system can capture up to 228 channels simultaneously at a 500?kHz sampling rate. Beam patterns are reconstructed in azimuth, elevation, and frequency for visualization and further analysis. Validation of the array measurement system and post-processing functions is shown by reconstructing the beam pattern of a transducer with a fixed circular aperture and comparing the result with a theoretical model. To demonstrate the system in use, transmit beam patterns of the big brown bat, Eptesicus fuscus, are shown. PMID:24437791

  8. A cross-ecosystem comparison of spatial and temporal patterns of covariation in the recruitment of functionally analogous fish stocks

    NASA Astrophysics Data System (ADS)

    Megrey, Bernard A.; Hare, Jonathan A.; Stockhausen, William T.; Dommasnes, Are; Gjøsæter, Harald; Overholtz, William; Gaichas, Sarah; Skaret, Georg; Falk-Petersen, Jannike; Link, Jason S.; Friedland, Kevin D.

    2009-04-01

    Temporal and spatial patterns of recruitment ( R) and spawning stock biomass ( S) variability were compared among functionally analogous species and similar feeding guilds from six marine ecosystems. Data were aggregated into four regions including the Gulf of Maine/Georges Bank, the Norwegian/Barents Seas, the eastern Bering Sea, and the Gulf of Alaska. Variability was characterized by calculating coefficients of variation and anomalies for three response variables: ln( R), ln( R/ S), and stock-recruit model residuals. Patterns of synchrony and asynchrony in the response variables were examined among and between ecosystems, between- and within-ocean basins and among functionally analogous species groups using pair-wise correlation analysis corrected for within-time series autocorrelation, multivariate cross-correlation analyses and regime shift detectors. Time series trends in response variables showed consistent within basin similarities and consistent and coherent differences between the Atlantic and Pacific basin ecosystems. Regime shift detection algorithms identified two broad-scale regime shift time periods for the pelagic feeding guild (1972-1976 and 1999-2002) and possibly one for the benthic feeding guild (1999-2002). No spatial patterns in response variable coefficients of variation were observed. Results from multivariate cross-correlation analysis showed similar trends. The data suggest common external factors act in synchrony on stocks within ocean basins but temporal stock patterns, often of the same species or functional group, between basins change in opposition to each other. Basin-scale results (similar within but different between) suggest that the two geographically broad areas are connected by unknown mechanisms that, depending on the year, may influence the two basins in opposite ways. This work demonstrates that commonalities and synchronies in recruitment fluctuations can be found across geographically distant ecosystems but biophysical causes of the fluctuations remain difficult to identify.

  9. Seasonal suspended particles distribution patterns in Western South Yellow Sea based on Acoustic Doppler Current Profiler observation

    NASA Astrophysics Data System (ADS)

    Li, Jianchao; Li, Guangxue; Xu, Jishang; Qiao, Lulu; Dong, Ping; Ding, Dong; Liu, Shidong; Sun, Pingkuo

    2015-06-01

    An Acoustic Doppler Current Profiler (ADCP) observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters (SPM) distribution pattern. The SPM concentration could be semi-quantitatively represented by backscatter intensity (Sv), converted by the echo intensity (EI) of ADCP. Results show two types of SPM in the water column: the quasi-biological SPM and quasi-mineral SPM. The quasi-biological SPM mainly exists in summer half year and is concentrated above the thermocline. It has periodically diurnal variations with high concentration at night and low concentration in the daytime. The quasi-mineral SPM is located in lower part of the water column, with similar relation to monthly tidal current variation all year round. However, the daily quasi-mineral SPM distribution patterns vary between summer and winter half year. The sunlight is thought to be the origin factor leading to the diurnally vertical motion of the biological features, which might cause the diurnal Sv variation. Unlike in winter half year when tidal current is relatively single driving force of the monthly SPM pattern, the high speed current near the thermocline is also responsible for the concentration of quasi-mineral SPM in summer half year. The sediment input difference between summer and winter half year contribute to the varied daily variation of quasi-mineral SPM with re-suspended SPM in winter and sediments from Yellow Sea Mud Area (YSMA) in summer. The seasonal variations in hydrodynamics, water structure and heavy-wind incidents are the primary factors influencing the differential seasonal SPM distribution patterns.

  10. High-order space-time finite element schemes for acoustic and viscodynamic wave equations with temporal decoupling

    PubMed Central

    Banks, H T; Birch, Malcolm J; Brewin, Mark P; Greenwald, Stephen E; Hu, Shuhua; Kenz, Zackary R; Kruse, Carola; Maischak, Matthias; Shaw, Simon; Whiteman, John R

    2014-01-01

    We revisit a method originally introduced by Werder et al. (in Comput. Methods Appl. Mech. Engrg., 190:6685–6708, 2001) for temporally discontinuous Galerkin FEMs applied to a parabolic partial differential equation. In that approach, block systems arise because of the coupling of the spatial systems through inner products of the temporal basis functions. If the spatial finite element space is of dimension D and polynomials of degree r are used in time, the block system has dimension (r + 1)D and is usually regarded as being too large when r > 1. Werder et al. found that the space-time coupling matrices are diagonalizable over for r ?100, and this means that the time-coupled computations within a time step can actually be decoupled. By using either continuous Galerkin or spectral element methods in space, we apply this DG-in-time methodology, for the first time, to second-order wave equations including elastodynamics with and without Kelvin–Voigt and Maxwell–Zener viscoelasticity. An example set of numerical results is given to demonstrate the favourable effect on error and computational work of the moderately high-order (up to degree 7) temporal and spatio-temporal approximations, and we also touch on an application of this method to an ambitious problem related to the diagnosis of coronary artery disease. Copyright © 2014 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons Ltd. PMID:25834284

  11. Radiative heating of acoustically levitated nano-silica droplets: Internal flow pattern leading to ring or bowl shaped structure

    NASA Astrophysics Data System (ADS)

    Saha, Abhishek; Tijerino, Erick; Kumar, Ranganathan; Basu, Saptarshi

    2010-11-01

    An experimental setup using radiative heating has been used to understand the thermophysical phenomena inside acoustically levitated droplets. In this transformation process, through IR thermography and high speed imaging, events such as vaporization, precipitation have been recorded at high temporal resolution; leading to bowl or ring shaped structures. High solute loading is seen to form high concentration precipitate near the surface with a weak center linkage which results in a horizontal ring formation initially. Droplet recirculation is more effective at lower concentrations, inducing a bridge formation near the center leading to a bowl formation. With non-uniform particle distribution, these structures can experience rupture which modifies the droplet rotational speed with preferential orientation. PIV on sub millimeter sized droplets shows presence of strong single core vortex around droplet center. Study with droplet diameter and viscosity of the liquid leads to the conclusion that the strength of the vortex is dependent on these parameters. Further investigation with LIF confirms preferential accumulation of particles at the bottom of the droplet.

  12. The temporal and spatial expression pattern of the LGI1 epilepsy predisposition gene during mouse embryonic cranial development

    PubMed Central

    2011-01-01

    Background Mutations in the LGI1 gene predispose to a rare, hereditary form of temporal epilepsy. Currently, little is known about the temporal and spatial expression pattern of Lgi1 during normal embryogenesis and so to define this more clearly we used a transgenic mouse line that expresses GFP under the control of Lgi1 cis-regulatory elements. Results During embryonic brain growth, high levels of Lgi1 expression were found in the surface ectoderm, the neuroepithelium, mesenchymal connective tissue, hippocampus, and sensory organs, such as eye, tongue, and the olfactory bulb. Lgi1 was also found in the cranial nerve nuclei and ganglia, such as vestibular, trigeminal, and dorsal ganglia. Expression of Lgi1 followed an orchestrated pattern during mouse development becoming more subdued in areas of the neocortex of the mid- and hind-brain in early postnatal animals, although high expression levels were retained in the choroid plexus and hippocampus. In late postnatal stages, Lgi1 expression continued to be detected in many areas in the brain including, hippocampus, paraventricular thalamic nuclei, inferior colliculus, and the cerebral aqueduct. We also showed that Lgi1-expressing cells co-express nestin, DCX, and beta-III tubulin suggesting that Lgi1-expressing cells are migratory neuroblasts. Conclusion These observations imply that Lgi1 may have a role in establishing normal brain architecture and neuronal functions during brain development suggesting that it may be involved in neurogenesis and neuronal plasticity, which become more specifically defined in the adult animal. PMID:21569517

  13. Temporal variability of remotely sensed suspended sediment and sea surface temperature patterns in Mobile Bay, Alabama

    USGS Publications Warehouse

    Rucker, J.B.; Stumpf, R.P.; Schroeder, W.W.

    1990-01-01

    Distribution patterns of suspended sediments and sea surface temperatures in, Mobile Bay were derived from algorithms using digital data from the visible, near infrared, and infrared channels of the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-TIROS-N satellite. Closely spaced AVHRR scenes for January 20, 24, and 29, 1982, were compared with available environmental information taken during the same period. A complex interaction between river discharge, winds, and astronomical tides controlled the distribution patterns of suspended sediments. These same variables, coupled with air temperatures, also governed the distribution patterns of sea surface temperatures. ?? 1990 Estuarine Research Federation.

  14. Computed tomography of temporal bone pneumatization. 1. Normal pattern and morphology

    SciTech Connect

    Virapongse, C.; Sarwar, M.; Bhimani, S.; Sasaki, C.; Shapiro, R.

    1985-09-01

    The pneumatization of 141 normal temporal bones on computed tomography (CT) was evaluated in 100 patients. Because of the controversy surrounding the sclerotic squamomastoid (mastoid), temporal bones with this finding were discarded. A CT index of pneumatization was based on the pneumatized area and the number of cells seen within a representative scanning section. Results suggest that squamomastoid pneumatization follows the classic normal distribution and does not correlate with age, gender, or laterality. A high degree of symmetry was found in 41 patients who had both ears examined. Air-cell configuration was variable. Air-cell size tended to increase progressively from the mastoid antrum. The scutum pseudotumor appearance caused by incomplete pneumatization was seen frequently, and should not be mistaken for mastoiditis or an osteoma. Thick sections producing partial-volume effect may also produce this spurious finding. Therefore, when searching for mucosal thickening due to mastoiditis, large air cells should preferably be analyzed.

  15. Decoding temporal and spatial patterns of fault uplift using transient river long profiles

    Microsoft Academic Search

    Alexander C. Whittaker; Mikaël Attal; Patience A. Cowie; Gregory E. Tucker; Gerald Roberts

    2008-01-01

    We present detailed observations of rivers crossing active normal faults in the Central Apennines, Italy, where excellent constraints exist on the temporal and spatial history of fault movement. We demonstrate that rivers with drainage areas >10 km2 and crossing faults that have undergone an increase in throw rate within the last 1 My, have significant long-profile convexities. In contrast, channels that cross

  16. Temporal and Spatial Patterns of Bartonella Infection in Black-tailed Prairie Dogs ( Cynomys ludovicianus )

    Microsoft Academic Search

    Ying Bai; M. Y. Kosoy; C. Ray; R. J. Brinkerhoff; S. K. Collinge

    2008-01-01

    We describe the temporal dynamics and spatial distribution of Bartonella in black-tailed prairie dogs (Cynomys ludovicianus) based on a longitudinal study conducted in 20 black-tailed prairie dog (BTPD) colonies in Boulder County, CO from 2003 to\\u000a 2005. Bartonella infection was widely distributed in all colonies with an overall prevalence of 23.1%, but varied by colony from 4.8% to 42.5%\\u000a and

  17. Spatial pattern of soil moisture and its temporal stability within profiles on a loessial slope in northwestern China

    NASA Astrophysics Data System (ADS)

    Jia, Yu-Hua; Shao, Ming-An; Jia, Xiao-Xu

    2013-07-01

    Temporal stability of spatial distributions of soil moisture are usually observed after repeated surveys of soil moisture across an area. To understand how temporal stability of soil moisture varied with soil depth under the combined influences of vegetation and local topography, we collected soil moisture data at intervals of 10 cm within 1-m profiles on a loessial slope in China in four plots (61 m × 5 m) under different types of vegetation (Korshinsk peashrub, KOP; purple alfalfa, ALF; natural fallow, NAF; millet, MIL). Measurements of soil water content were made by neutron probes on 15 occasions between 2010 and 2012. Soil moisture distributions in both the vertical and horizontal dimensions were investigated to describe its spatial pattern and to lay the groundwork for better understanding its temporal stability characteristics. The results indicated that: (1) soil moisture presented different vertical but similar horizontal trends in the four plots, with significant correlations of soil moisture occurring primarily among adjacent soil layers irrespective of vegetation types, mostly in soil profiles under KOP and ALF and less frequently in soil profiles under NAF and MIL; (2) based on Spearman rank correlation coefficients, with increasing depth temporal stability generally increased under KOP and MIL, but first increased and then decreased under ALF, and increased after the first three measurements under NAF; (3) based on the relative difference technique, points with extreme moisture tended to remain representative at more depths than did points with average moisture and their time stability increased with increasing soil depth; and (4) the correlation between MRD (mean relative differences) and the wetness index weakened with soil depth. The relationship between SDRD (the standard deviation of MRD) and the wetness index varied nonlinearly with soil depth. Vegetation type, soil depth and the wetness index, in descending order of influence, had significant effects on the temporal stability of soil moisture. Among selected soil properties, saturated hydraulic conductivity, bulk density and soil organic carbon all significantly affected the SDRDs. These observations are expected to add valuable information to the theory of temporal stability and for the practices of soil moisture management.

  18. Dependence of Empirical Fundamental Diagram on Spatial-Temporal Traffic Patterns Features

    Microsoft Academic Search

    Boris S. Kerner

    2003-01-01

    It is shown that the branch of the empirical fundamental diagram for\\u000acongested traffic strongly depends both on the type of the congested pattern at\\u000aa freeway bottleneck and on the freeway location where the fundamental diagram\\u000ais measured. Since the type of the pattern at the same bottleneck can depend on\\u000atraffic demand, a qualitative form of the empirical

  19. Complex Acoustic Pattern Learning in Songbirds and Humans Kimberly M. Fenn (kmfenn@uchicago.edu)

    E-print Network

    Gentner, Timothy

    structures of natural language is a uniquely human faculty (Fitch et al., 2005; Hauser et al., 2002; language; syntax; recursion Introduction How we acquire knowledge of linguistic patterns has been a controversial theoretical issue in research on language development. One view is that human language cannot

  20. Temporal pattern cues in vibrational risk assessment by embryos of the red-eyed treefrog, Agalychnis callidryas.

    PubMed

    Warkentin, Karen M; Caldwell, Michael S; McDaniel, J Gregory

    2006-04-01

    The embryos of red-eyed treefrogs, Agalychnis callidryas, use vibrations transmitted through their arboreal egg clutch to cue escape hatching behavior when attacked by egg-eating snakes. Hatching early increases the risk of predation in the water, so embryos should avoid it unless they are in danger. We exposed egg clutches to intermittent vibrations with different combinations of vibration duration and spacing to examine the role of simple temporal pattern cues in the escape hatching response. Stimuli were bursts of synthetic white noise from 0 to 100 Hz, including the range of frequencies with substantial energy in snake attacks, and had approximately rectangular amplitude envelopes. Embryos hatched in response to a small range of temporal patterns and not in response to many others, rather than hatching to most vibrations except for certain patterns perceived as safe. Neither cycle length nor duty cycle predicted hatching response, except at extreme values where no hatching occurred; the highest energy stimuli elicited little or no hatching. Both vibration duration and inter-vibration interval strongly affected the hatching response. The highest levels of hatching were to durations of 0.5 s combined with intervals of 1.5-2.5 s, and hatching decreased gradually with increasing difference of either duration or interval from these most effective stimuli. Vibration duration and interval appear to function as two necessary elements of a composite cue, rather than as redundant cues. This increases response specificity and reduces the range of stimuli that elicit hatching, likely reducing the chance of hatching unnecessarily in a benign disturbance. Vibration-cued hatching in A. callidryas embryos offers an opportunity to experimentally assess the behavioral decision rules underlying an effective and costly anti-predator defense. PMID:16574797

  1. Temporal variation in end-member chemistry and its influence on runoff mixing patterns in a forested, Piedmont catchment

    NASA Astrophysics Data System (ADS)

    Inamdar, Shreeram; Dhillon, Gurbir; Singh, Shatrughan; Dutta, Sudarshan; Levia, Delphis; Scott, Durelle; Mitchell, Myron; Stan, John; McHale, Patrick

    2013-04-01

    Runoff mixing patterns for base flow and 42 storm events were investigated for a 3 year period (2008-2010) in a 12 ha forested catchment in the mid-Atlantic, Piedmont region of the USA. Eleven distinct runoff sources were sampled independently and included: precipitation, throughfall, stemflow, litter leachate, wetland soil water, tension soil water, shallow groundwater, groundwater seeps, hyporheic water, riparian groundwater, and deep groundwater. A rigorous end-member mixing analysis (EMMA) was implemented and all base flow, storm-flow, and end-member chemistries were evaluated in a two-dimensional mixing space. End-members enclosed stream water chemistry and displayed a systematic continuum in EMMA space. Base-flow chemistry of stream waters was similar to groundwater seeps. Storm-event runoff was attributed to contributions from surficial sources (precipitation, throughfall, stemflow, and litter leachate) on the rising limb of the discharge hydrograph that was followed by soil and shallow groundwater sources on the recession limb of the hydrograph. The shapes of the storm-event hysteresis loops (wide versus tight, linear patterns) varied with hydrologic conditions from wet, hydrologically well-connected conditions to a dry, disconnected state. Detailed temporal data on end-member chemistry allowed us to explain the changes in stream water hysteresis patterns and runoff mixing space to shifts in end-member chemistry that occurred as the catchment became hydrologically disconnected. These results highlight the need to recognize the temporal variation in end-member chemistry as a function of catchment wetness and the need to collect high-frequency data on both--stream water as well as potential runoff end-members to better characterize catchment flow paths and mixing responses.

  2. Spatial and temporal patterns of carabid activity-density in cereals do not explain levels of predation on weed seeds.

    PubMed

    Saska, P; van der Werf, W; de Vries, E; Westerman, P R

    2008-04-01

    Seed predation is an important component of seed mortality of weeds in agro-ecosystems, but the agronomic use and management of this natural weed suppression is hampered by a lack of insight in the underlying ecological processes. In this paper, we investigate whether and how spatial and temporal variation in activity-density of granivorous ground beetles (Coleoptera: Carabidae) results in a corresponding pattern of seed predation. Activity-density of carabids was measured by using pitfall traps in two organic winter wheat fields from March to July 2004. Predation of seeds (Capsella bursa-pastoris, Lamium amplexicaule, Poa annua and Stellaria media) was assessed using seed cards at the same sites and times. As measured by pitfall traps, carabids were the dominant group of insects that had access to the seed cards. In the field, predation of the four different species of seed was in the order: C. bursa-pastoris>P. annua>S. media>L. amplexicaule; and this order of preference was confirmed in the laboratory using the dominant species of carabid. On average, seed predation was higher in the field interior compared to the edge, whereas catches of carabids were highest near the edge. Weeks with elevated seed predation did not concur with high activity-density of carabids. Thus, patterns of spatial and temporal variation in seed predation were not matched by similar patterns in the abundance of granivorous carabid beetles. The lack of correspondence is ascribed to effects of confounding factors, such as weather, the background density of seeds, the composition of the carabid community, and the phenology and physiological state of the beetles. Our results show that differences in seed loss among weed species may be predicted from laboratory trials on preference. However, predator activity-density, as measured in pitfall traps, is an insufficient predictor of seed predation over time and space within a field. PMID:18076785

  3. Factors controlling the long-term temporal and spatial patterns of nitrate-nitrogen export in a dairy farming watershed.

    PubMed

    Jiang, Rui; Wang, Chun-ying; Hatano, Ryusuke; Kuramochi, Kanta; Hayakawa, Atsushi; Woli, Krishna P

    2015-04-01

    It is difficult to investigate the factors that control the riverine nitrate-nitrogen (NO3--N) export in a watershed which gains or losses groundwater. To control the NO3--N contamination in these watersheds, it is necessary to investigate the factors that are related to the export of NO3--N that is only produced by the watershed itself. This study was conducted in the Shibetsu watershed located in eastern Hokkaido, Japan, which gains external groundwater contribution (EXT) and 34% of the annual NO3--N loading occurs through EXT. The riverine NO3--N exports from 1980 to 2009 were simulated by the SWAT model, and the factors controlling the temporal and spatial patterns of NO3--N exports were investigated without considering the EXT. The results show that hydrological events control NO3--N export at the seasonal scale, while the hydrological and biogeochemical processes are likely to control NO3--N export at the annual scale. There was an integrated effect among the land use, topography, and soil type related to denitrification process, that regulated the spatial patterns of NO3--N export. The spatial distribution of NO3--N export from hydrologic response units (HRUs) identified the agricultural areas with surplus N that are vulnerable to nitrate contamination. A new standard for the N fertilizer application rate including manure application should be given to control riverine NO3--N export. This study demonstrates that applying the SWAT model is an appropriate method to determine the temporal and spatial patterns of NO3--N export from the watershed which includes EXT and to identify the crucial pollution areas within a watershed in which the management practices can be improved to more effectively control NO3--N export to water bodies. PMID:25805369

  4. Data integration for spatio-temporal patterns of gene expression of zebrafish development: the GEMS database.

    PubMed

    Belmamoune, Mounia; Verbeek, Fons J

    2008-01-01

    The Gene Expression Management System (GEMS) is a database system for patterns of gene expression. These patterns result from systematic whole-mount fluorescent in situ hybridization studies on zebrafish embryos. GEMS is an integrative platform that addresses one of the important challenges of developmental biology: how to integrate genetic data that underpin morphological changes during embryogenesis. Our motivation to build this system was by the need to be able to organize and compare multiple patterns of gene expression at tissue level. Integration with other developmental and biomolecular databases will further support our understanding of development. The GEMS operates in concert with a database containing a digital atlas of zebrafish embryo; this digital atlas of zebrafish development has been conceived prior to the expansion of the GEMS. The atlas contains 3D volume models of canonical stages of zebrafish development in which in each volume model element is annotated with an anatomical term. These terms are extracted from a formal anatomical ontology, i.e. the Developmental Anatomy Ontology of Zebrafish (DAOZ). In the GEMS, anatomical terms from this ontology together with terms from the Gene Ontology (GO) are also used to annotate patterns of gene expression and in this manner providing mechanisms for integration and retrieval. The annotations are the glue for integration of patterns of gene expression in GEMS as well as in other biomolecular databases. At the one hand, zebrafish anatomy terminology allows gene expression data within GEMS to be integrated with phenotypical data in the 3D atlas of zebrafish development. At the other hand, GO terms extend GEMS expression patterns integration to a wide range of bioinformatics resources. PMID:20134060

  5. Patterns of life in temporal data: indexing and hashing for fast and relevant data retrieval

    NASA Astrophysics Data System (ADS)

    Jacobsen, Matthew; Levchuk, Georgiy; Weston, Mark; Roberts, Jennifer

    2014-05-01

    As datasets with time-series records, such as computer logs or financial transactions, grow larger, indexing solutions are needed that can efficiently filter out irrelevant records while retrieving most of relevant ones. These methods must capture essential temporal properties present in the data, and provide a scalable way to generate the index and update it as the new records are presented. Current time-series analysis and indexing methods are insufficient, because the fixed features they rely on capture only limited periodicity in time-series data and become brittle when the time-series encode heterogeneous temporal behaviors and are noisy and incomplete. New indexing solutions must not only cluster the data, but also infer the meaningful characteristics and present them to the users to improve their understanding of the data. In this paper, we develop an indexing procedure based on typical latent behaviors within the time series. Our method (1) converts the data to a quantized format, (2) learns identifying behaviors generating the data, and (3) produces an index for the time series based on these behaviors. The method is found to outperform standard approaches to time series indexing in terms of recall and precision for varying degrees of data noise.

  6. Multivariate pattern analysis of the human medial temporal lobe revealed representationally categorical cortex and representationally agnostic hippocampus

    PubMed Central

    Huffman, Derek J.; Stark, Craig E.L.

    2014-01-01

    Contemporary theories of the medial temporal lobe (MTL) suggest that there are functional differences between the MTL cortex and the hippocampus. High-resolution functional magnetic resonance imaging and multivariate pattern analysis were utilized to study whether MTL subregions could classify categories of images, with the hypothesis that the hippocampus would be less representationally categorical than the MTL cortex. Results revealed significant classification accuracy for faces versus objects and faces versus scenes in MTL cortical regions—parahippocampal cortex and perirhinal cortex—with little evidence for category discrimination in the hippocampus. MTL cortical regions showed significantly greater classification accuracy than the hippocampus. The hippocampus showed significant classification accuracy for images compared to a non-mnemonic baseline task, suggesting that it responded to the images. Classification accuracy in a region of interest encompassing retrosplenial cortex and the posterior cingulate cortex posterior to retrosplenial cortex (RSC/PCC), showed a similar pattern of results to parahippocampal cortex, supporting the hypothesis that these regions are functionally related. The results suggest that parahippocampal cortex, perirhinal cortex, and RSC/PCC are representationally categorical and the hippocampus is more representationally agnostic, which is concordant with the hypothesis of the role of the hippocampus in pattern separation. PMID:24976498

  7. Spatial and Temporal Patterns of Small-Scale Mixing in Drake Passage

    Microsoft Academic Search

    Andrew F. Thompson; Sarah T. Gille; J. A. MacKinnon; Janet Sprintall

    2007-01-01

    Temperature and salinity profiles obtained with expendable CTD probes throughout Drake Passage between February 2002 and July 2005 are analyzed to estimate turbulent diapycnal eddy diffusivities to a depth of 1000 m. Diffusivity values are inferred from density\\/temperature inversions and internal wave vertical strain. Both methods reveal the same pattern of spatial variability across Drake Passage; diffusivity estimates from inversions

  8. Global Climate Patterns to Model the Spatial and Temporal Distribution of Vector-Borne Diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global climate patterns, such as the El Niño/Southern Oscillation (ENSO), have been shown to have an impact on vector-borne infectious disease outbreaks. In October 2006 the Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA/CPC) issued an unscheduled El Niño advi...

  9. Spatio-temporal expression patterns of Arabidopsis thaliana and Medicago truncatula defensin-like genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant genomes typically contain several hundred defensin-like (DEFL) genes that encode short proteins resembling defensins, which are antimicrobial polypeptides. Little is known about the expression patterns of DEFL genes because most were recently discovered and many are not well represented on sta...

  10. Environmental influences on temporal patterns of settlement in two littoral labrid fishes in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Raventos, N.; Macpherson, E.

    2005-06-01

    Correlations between daily fish settlement and environmental and physical parameters were examined during two consecutive years in two labrid species ( Symphodus roissali and Symphodus ocellatus) in the NW Mediterranean Sea. Both these species have a short planktonic larval duration (12±0.3 and 9±0.4 days, respectively) and limited offshore larval dispersal. Time-series analysis was used to compare the daily settlement patterns with various environmental variables, and non-linear generalized additive models (GAM) were used to examine the relationship between environmental conditions averaged over larval period and daily settlement patterns. Settlement was not uniform and took place as pulses of different length. Although the analyses detected a few significant correlations between day-to-day patterns in environmental variables and settlement (e.g. solar radiation, atmospheric pressure, daytime or nocturnal wind components), these were not consistent among years. In S. ocellatus, however, wind components (daytime or nighttime) explained part of the variance in settlement intensity. The correlations (GAM outputs) observed between settlement patterns and environmental variables (averaged during the whole planktonic period) suggest that calm weather during the planktonic period usually increases settlement success.

  11. Temporal and spatial expression patterns of the LEAFY homologue NLF during florogenesis in Narcissus tazetta

    Microsoft Academic Search

    Tal Noy-Porat; Rina Kamenetsky; Amram Eshel; Moshe A. Flaishman

    2010-01-01

    Studies of flower development in numerous plants suggest that the LEAFY gene (LFY) of Arabidopsis and its homologues in other species act as integrators of floral inductive signals and determine the fate of meristems. In Narcissus tazetta, the LFY homologue NLF was identified, and its expression pattern during flower development was studied under various temperature conditions. In N. tazetta, flower

  12. Temporal Patterns in Bacterial Communities in Three Temperate Lakes of Different Trophic Status

    Microsoft Academic Search

    A. C. Yannarell; A. D. Kent; G. H. Lauster; T. K. Kratz; E. W. Triplett

    2003-01-01

    Despite considerable attention in recent years, the composition and dynamics of lake bacterial communities over annual time scales are poorly understood. This study used automated ribosomal intergenic spacer analysis (ARISA) to explore the patterns of change in lake bacterial communities in three temperate lakes over 2 consecutive years. The study lakes included a humic lake, an oligotrophic lake, and a

  13. How Temporal and Spatial Aspects of Presenting Visualizations Affect Learning about Locomotion Patterns

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Edelmann, Jorg; Gerjets, Peter

    2012-01-01

    Two studies investigated the effectiveness of dynamic and static visualizations for a perceptual learning task (locomotion pattern classification). In Study 1, seventy-five students viewed either dynamic, static-sequential, or static-simultaneous visualizations. For tasks of intermediate difficulty, dynamic visualizations led to better…

  14. Multivoxel patterns in face-sensitive temporal regions reveal an encoding schema based on detecting life

    E-print Network

    Bucci, David J.

    , toy dogs). We used multivariate pattern analysis of BOLD responses to uncover the representational of faces by using animate and inanimate faces with human form (humans, mannequins) and dog form (real dogs occipital gyrus are organized by global facial form alone (human vs dog) while animacy becomes an additional

  15. Spatio-temporal patterns of neuronal activity: analysis of optical imaging data using geometric shape matching.

    PubMed

    Köhling, R; Reinel, J; Vahrenhold, J; Hinrichs, K; Speckmann, E-J

    2002-02-15

    Optical imaging of neuronal network activity yields information of spatial dynamics which generally is analyzed visually. The transient appearance of spatial activity patterns is difficult to gauge in a quantifiable manner, or may even altogether escape detection. Here, we employ geometric shape matching using Fréchet distances or straight skeletons to search for pre-selected patterns in optical imaging data with adjustable degrees of tolerance. Data were sampled from fluorescence changes of a voltage-sensitive dye recorded with a 464-photodiode array. Fluorescence was monitored in a neuronal network in vitro. Neuronal activity prompting fluorescence fluctuations consisted of spontaneous epileptiform discharges in neocortical slices from patients undergoing epilepsy surgery. The experiments show that: (a) spatial activity patterns can be detected in optical imaging data; (b) shapes such as "mini-foci" appear in close correlation to bioelectric discharges monitored with field potential electrodes in a reproducible manner; (c) Fréchet distances yield more conservative matches regarding rectangular, and less conservative hits with respect to radially symmetric shapes than the straight skeleton approach; and (d) tolerances of 0.03-0.1 are suited to detect faithful images of pre-selected shapes, whereas values >0.8 will report matches with any polygonal pattern. In conclusion, the methods reported here are suited to detect and analyze spatial, geometric dynamics in optical imaging data. PMID:11850035

  16. SPATIAL AND TEMPORAL PATTERNS OF MAIZE WEEVIL PRE-HARVEST INFESTATION IN CORN FIELDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three corn fields were sampled continuously for 6- or 8-wks to determine the invasion patterns of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), infestation. The weekly samplings started when the kernel moisture level was about 30%. The weevil infestation levels vari...

  17. Spatio-temporal patterns of soil water storage under dryland agriculture at the watershed scale

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water patterns vary significantly due to precipitation, soil properties, topographic features, and land use. We used empirical orthogonal function (EOF) analysis to characterize the spatial variability of soil water across a 37-ha field of the Washington State University Cook Agronomy Farm near...

  18. Bioaccumulation Patterns and Temporal Trends of Mercury Exposure in Wisconsin Common Loons

    Microsoft Academic Search

    Brick M. Fevold; Michael W. Meyer; Paul W. Rasmussen; Stanley A. Temple

    2003-01-01

    A long term field study was initiated by the Wisconsin Department of Natural Resources in 1992 to elucidate patterns of common loon (Gavia immer) mercury (Hg) exposure. Analysis of loon blood and feather samples collected from recaptured adult loons in Wisconsin 1992–2000 found evidence of a decline in overall body burdens of mercury in common loons for this region. The

  19. Two Phase Temporal-Spatial Autocorrelation of Urban Patterns: Revealing Focal Areas of Re-Urbanization in Tel Aviv-Yafo

    Microsoft Academic Search

    Idan Porat; Maxim Shoshany; Amnon Frenkel

    A new two-phase temporal-spatial analysis technique is presented for exploring core areas of re-urbanization in complex patterns\\u000a of urban change. The Local Autocorrelation of Pearson (LAoP) technique first computes temporal Pearson correlations between\\u000a time series of data for each sub-area and the city’s average time series and then computes the local Moran autocorrelation\\u000a (LISA) of these temporal correlations. This technique

  20. A comparison of EEG seizure patterns recorded with surface and depth electrodes in patients with temporal lobe epilepsy.

    PubMed

    Lieb, J P; Walsh, G O; Babb, T L; Walter, R D; Crandall, P H

    1976-06-01

    Surface and depth EEG seizure patterns were compared in 34 patients with intractable temporal lobe epilepsy in whom depth EEG electrodes had been chronically implanted in order to localize epileptogenic sites with a view to surgery. EEG records accompanied by clinical seizures, auras, no behavioral changes, as well as records for which no behavioral observations had been made, were judged with respect to the manner in which seizure activity originating unilaterally in the depth of one of the temporal lobes spread to the surface. For each EEG record, the onset of seizure activity in depth was classified as being focal or regional in form, and seizure activity was judged as: (1) not spreading to the surface, (2) spreading bilaterally and synchronously to the surface, (3) spreading initially to the surface ipsilateral to the depth site(s) in which the electrographic seizure first appeared, or (4) spreading initially to the surface contralateral to the depth site(s) in which the seizure activity initially occurred. EEG seizure activity was found to be less likely to propagate to the surface for those records that were either unaccompanied by behavior changes or accompanied only by auras than for those records accompanied by clinical seizures. In records accompanied by clinical seizures, seizure activity commonly propagated to the surface in a bilateral and synchronous fashion and was also found to spread initially to the ipsilateral but not to the contralateral surface. Anatomical and electrophysiological data accounting for the occurrence of ipsilateral spread were discussed. Diagnostic usefulness of surface recordings during clinical seizures in temporal lobe epilepsy was discussed. PMID:947745

  1. Spatial and temporal patterns in water chemistry of two high elevation lakes in southeast Wyoming

    SciTech Connect

    Musselman, R.C. [Forest Service, Fort Collins, CO (United States). Rocky Mountain Forest and Range Experiment Station

    1995-12-31

    The Glacier Lakes Ecosystem Experiments Site (GLEES) was established to examine the effects of atmospheric deposition and climate change on alpine and subalpine ecosystems. This report documents temporal and spatial trends during 1993 in water chemistry in East and West Glacier Lakes. Data are presented on seasonal and lake depth changes in water chemistry of the two lakes. The application of the results to appropriate sampling protocols for two alpine lakes is discussed. Both lakes were sampled during the same day, at midday. Samples were kept cool, returned to the lab the same day, and filtered for analysis. Samples were analyzed for cations and anions, pH, and conductivity at the Rocky Mountain Station Water Chemistry laboratory. Silica and aluminum were also measured for some sample dates.

  2. Metals in horseshoe crab eggs from Delaware Bay, USA: temporal patterns from 1993 to 2012.

    PubMed

    Burger, Joanna; Tsipoura, Nellie

    2014-10-01

    The health of horseshoe crab (Limulus polyphemus) eggs is important not only to maintain horseshoe crab populations, but because they are a resource for higher trophic levels, such as fish and shorebirds. We examined the concentrations of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in the eggs of horseshoe crabs from Delaware Bay (between New Jersey and Delaware, USA) in 1993, 1994, 1995, 1999, 2000, and 2012 to determine if there were significant temporal changes and if levels appear to pose a health risk to the crabs themselves, or to predators that consume them. All metal levels declined in horseshoe crab eggs between 1994 and 2012, although the declines were much less consistent for lead and chromium than that for mercury and cadmium. Levels of contaminants found in these eggs are well below those known to cause adverse effects in the crabs themselves or to organisms that consume them, such as migrating shorebirds. PMID:25015345

  3. A network that performs brute-force conversion of a temporal sequence to a spatial pattern: relevance to odor recognition

    PubMed Central

    Sanders, Honi; Kolterman, Brian E.; Shusterman, Roman; Rinberg, Dmitry; Koulakov, Alexei; Lisman, John

    2014-01-01

    A classic problem in neuroscience is how temporal sequences (TSs) can be recognized. This problem is exemplified in the olfactory system, where an odor is defined by the TS of olfactory bulb (OB) output that occurs during a sniff. This sequence is discrete because the output is subdivided by gamma frequency oscillations. Here we propose a new class of “brute-force” solutions to recognition of discrete sequences. We demonstrate a network architecture in which there are a small number of modules, each of which provides a persistent snapshot of what occurs in a different gamma cycle. The collection of these snapshots forms a spatial pattern (SP) that can be recognized by standard attractor-based network mechanisms. We will discuss the implications of this strategy for recognizing odor-specific sequences generated by the OB. PMID:25278870

  4. The Spatio-Temporal Distribution Patterns of Biting Midges of the Genus Culicoides in Salta Province, Argentina

    PubMed Central

    Aybar, Cecilia A. Veggiani; Juri, María J. Dantur; Santana, Mirta; de Grosso, Mercedes S. Lizarralde; Spinelli, Gustavo R.

    2012-01-01

    The goal of this survey was to analyze the spatio-temporal distribution patterns of Culicoides Latreille species (Diptera: Ceratopogonidae) and their relationship with environmental variables in Salta, northwestern Argentina. Culicoides were collected monthly from January 2003 through December 2005. The influence of the climatic variables on population abundance was analyzed with a multilevel Poisson regression. A total of 918 specimens belonging to five species were collected. The most abundant species was Culicoides paraensis Goeldi (65.5%), followed by Culicoides lahillei Iches (14.6%) and Culicoides debilipalpis Lutz (7.6%). The highest seasonal abundance for C. paraensis, C. debilipalpis and C. lahillei occurred during the spring and summer. A Poisson regression analysis showed that the mean maximum and minimum temperature and the mean maximum and minimum humidity were the variables with the greatest influence on the population abundance of Culicoides species. PMID:23461794

  5. Temporal patterns in coral reef, seagrass and mangrove communities from Chengue bay CARICOMP site (Colombia): 1993-2008.

    PubMed

    Rodríguez-Ramírez, Alberto; Garzón-Ferreira, Jaime; Batista-Morales, Angélica; Gil, Diego L; Gómez-López, Diana Isabel; Gómez-Campo, Kelly; López-Londoño, Tomás; Navas-Camacho, Raúl; Reyes-Nivia, María Catalina; Vega-Sequeda, Johanna

    2010-10-01

    Few monitoring programs have simultaneously assessed the dynamics of linked marine ecosystems (coral reefs, seagrass beds and mangroves) to document their temporal and spatial variability. Based on CARICOMP protocol we evaluated permanent stations in coral reefs, seagrass beds and mangroves from 1993 to 2008 in Chengue Bay at the Tayrona Natural Park, Colombian Caribbean. Overall, the studied ecosystems showed a remarkable stability pattern over the monitoring period. While there were annual variations in coral reefs (coral cover) and mangroves (litterfall) caused by hurricane Lenny in 1999, particular trends in seagrass (leaf area index and leaf productivity) appear to reflect the natural variability in this ecosystem. We suggest that monitoring sites at the three marine ecosystems had in general a healthy development in the last 16 years. Our results are critical to locally improve the management strategies (Tayrona Natural Park) and to understand the long-term dynamics of closely associated marine ecosystems in the Caribbean. PMID:21299095

  6. Analysis of motor patterns in the isolated guinea-pig large intestine by spatio-temporal maps.

    PubMed

    D'Antona, G; Hennig, G W; Costa, M; Humphreys, C M; Brookes, S J

    2001-10-01

    We investigated and quantified the spontaneous patterns of motility in the isolated guinea-pig proximal and distal colon taken from adult animals. During spontaneous emptying, profiles of proximal and distal colon were recorded with a video camera, and image analysis was used to construct spatio-temporal maps of the motions of the intestinal wall. Four patterns of motility were recorded. In the proximal colon there were neurally mediated contractions that propagated in the aboral direction at 4.1 mm s(-1), gently pushing the soft contents aborally; these are likely to represent spontaneous peristaltic behaviour. A second pattern, insensitive to tetrodotoxin (TTX; 0.6 microM), consisted, in both oral and aboral propagation, of shallow contractions of the circular muscle (ripples). These contractions propagated aborally at 2.8 +/- 0.45 mm s(-1) and orally at 2.03 +/- 0.31 mm s(-1) (n=10). Of these TTX-resistant contractions, 22.5% propagated both orally and aborally from a common origin. The orally propagated component of these myogenic contractions is likely to correspond to the antiperistalsis widely described in the proximal colon. In the distal colon, two patterns of motor activity were observed. One, induced by natural or artificial pellets, consisted of peristaltic contractions that pushed the pellets aborally at 0.8 mm s(-1) and expelled a pellet every 108 s. In the interval between pellet propulsion and after the distal colon had emptied all of its pellets a second, nerve-mediated pattern of motor activity, consisting of clusters of annular circular muscle contractions separated by short dilated regions, slowly propagated aborally at 0.3 mm s(-1). Both of these motor patterns were abolished by TTX (0.6 microM). A latex balloon, inserted at the oral end of the empty isolated distal colon and inflated to a size similar to faecal pellets, was propelled at 1.4 mm s(-1). Epoxy resin-covered natural pellets were propelled at a similar speed of 1.6 mm s(-1). Our data revealed that myogenic and neurogenic patterns of propagated contractions in the colon occur in isolated preparations and are involved in emptying the colon. PMID:11696110

  7. Modeling self-organized spatio-temporal patterns of PIP3 and PTEN during spontaneous cell polarization

    NASA Astrophysics Data System (ADS)

    Knoch, Fabian; Tarantola, Marco; Bodenschatz, Eberhard; Rappel, Wouter-Jan

    2014-08-01

    During spontaneous cell polarization of Dictyostelium discoideum cells, phosphatidylinositol (3,4,5)-triphoshpate (PIP3) and PTEN (phosphatase tensin homolog) have been identified as key signaling molecules which govern the process of polarization in a self-organized manner. Recent experiments have quantified the spatio-temporal dynamics of these signaling components. Surprisingly, it was found that membrane-bound PTEN can be either in a high or low state, that PIP3 waves were initiated in areas lacking PTEN through an excitable mechanism, and that PIP3 was degraded even though the PTEN concentration remained low. Here we develop a reaction-diffusion model that aims to explain these experimental findings. Our model contains bistable dynamics for PTEN, excitable dynamics for PIP3, and postulates the existence of two species of PTEN with different dephosphorylation rates. We show that our model is able to produce results that are in good qualitative agreement with the experiments, suggesting that our reaction-diffusion model underlies the self-organized spatio-temporal patterns observed in experiments.

  8. SuperFly: a comparative database for quantified spatio-temporal gene expression patterns in early dipteran embryos

    PubMed Central

    Cicin-Sain, Damjan; Pulido, Antonio Hermoso; Crombach, Anton; Wotton, Karl R.; Jiménez-Guri, Eva; Taly, Jean-François; Roma, Guglielmo; Jaeger, Johannes

    2015-01-01

    We present SuperFly (http://superfly.crg.eu), a relational database for quantified spatio-temporal expression data of segmentation genes during early development in different species of dipteran insects (flies, midges and mosquitoes). SuperFly has a special focus on emerging non-drosophilid model systems. The database currently includes data of high spatio-temporal resolution for three species: the vinegar fly Drosophila melanogaster, the scuttle fly Megaselia abdita and the moth midge Clogmia albipunctata. At this point, SuperFly covers up to 9 genes and 16 time points per species, with a total of 1823 individual embryos. It provides an intuitive web interface, enabling the user to query and access original embryo images, quantified expression profiles, extracted positions of expression boundaries and integrated datasets, plus metadata and intermediate processing steps. SuperFly is a valuable new resource for the quantitative comparative study of gene expression patterns across dipteran species. Moreover, it provides an interesting test set for systems biologists interested in fitting mathematical gene network models to data. Both of these aspects are essential ingredients for progress toward a more quantitative and mechanistic understanding of developmental evolution. PMID:25404137

  9. Automatic Segmentation of Polypoidal Choroidal Vasculopathy from Indocyanine Green Angiography Using Spatial and Temporal Patterns

    PubMed Central

    Lin, Wei-Yang; Yang, Sheng-Chang; Chen, Shih-Jen; Tsai, Chia-Ling; Du, Shuo-Zhao; Lim, Tock-Han

    2015-01-01

    Purpose To develop a computer-aided diagnostic tool for automated detection and quantification of polypoidal regions in indocyanine green angiography (ICGA) images. Methods The ICGA sequences of 59 polypoidal choroidal vasculopathy (PCV) treatment–naïve patients from five Asian countries (Hong Kong, Singapore, South Korea, Taiwan, and Thailand) were provided by the EVEREST study. The ground truth was provided by the reading center for the presence of polypoidal regions. The proposed detection algorithm used both temporal and spatial features to characterize the severity of polypoidal lesions in ICGA sequences. Leave-one-out cross validation was carried out so that each patient was used once as the validation sample. For each patient, a fixed detection threshold of 0.5 on the severity was applied to obtain sensitivity, specificity, and balanced accuracy with respect to the ground truth. Results Our system achieved an average accuracy of 0.9126 (sensitivity = 0.9125, specificity = 0.9127) for detection of polyps in the 59 ICGA sequences. Among the total of 222 features extracted from ICGA sequence, the spatial variances exhibited best discriminative power in distinguishing between polyp and nonpolyp regions. The results also indicated the importance of combining spatial and temporal features to further improve detection accuracy. Conclusions The developed software provided a means of detecting and quantifying polypoidal regions in ICGA images for the first time. Translational Relevance This preliminary study demonstrated a computer-aided diagnostic tool, which enables objective evaluation of PCV and its progression. Ophthalmologists can easily visualize the polypoidal regions and obtain quantitative information about polyps by using the proposed system. PMID:25806144

  10. Clinical and temporal patterns of severe pneumonia causing critical illness during Hajj

    PubMed Central

    2012-01-01

    Background Pneumonia is a leading cause of hospitalization during Hajj and susceptibility and transmission may be exacerbated by extreme spatial and temporal crowding. We describe the number and temporal onset, co–morbidities, and outcomes of severe pneumonia causing critical illness among pilgrims. Method A cohort study of all critically ill Hajj patients, of over 40 nationalities, admitted to 15 hospitals in 2 cities in 2009 and 2010. Demographic, clinical, and laboratory data, and variables necessary for calculation of the Acute Physiology and Chronic Health Evaluation IV scores were collected. Results There were 452 patients (64.6% male) who developed critical illness. Pneumonia was the primary cause of critical illness in 123 (27.2%) of all intensive care unit (ICU) admissions during Hajj. Pneumonia was community (Hajj)–acquired in 66.7%, aspiration–related in 25.2%, nosocomial in 3.3%, and tuberculous in 4.9%. Pneumonia occurred most commonly in the second week of Hajj, 95 (77.2%) occurred between days 5–15 of Hajj, corresponding to the period of most extreme pilgrim density. Mechanical ventilation was performed in 69.1%. Median duration of ICU stay was 4 (interquartile range [IQR] 1–8) days and duration of ventilation 4 (IQR 3–6) days. Commonest preexisting co–morbidities included smoking (22.8%), diabetes (32.5%), and COPD (17.1%). Short–term mortality (during the 3–week period of Hajj) was 19.5%. Conclusion Pneumonia is a major cause of critical illness during Hajj and occurs amidst substantial crowding and pilgrim density. Increased efforts at prevention for at risk pilgrim prior to Hajj and further attention to spatial and physical crowding during Hajj may attenuate this risk. PMID:22591189

  11. Temporal trends of perfluorooctanesulfonate isomer and enantiomer patterns in archived Swedish and American serum samples.

    PubMed

    Liu, Yanna; Pereira, Alberto S; Beesoon, Sanjay; Vestergren, Robin; Berger, Urs; Olsen, Geary W; Glynn, Anders; Martin, Jonathan W

    2015-02-01

    Human perfluorooctanesulfonate (PFOS) body burdens are attributable to both direct PFOS and indirect PFOS precursor (PreFOS) exposure. The relative importance of these two pathways has been estimated, but the relative temporal trajectory of exposure to PFOS and PreFOS has not been examined. Here, two hypothesized biomarkers of PreFOS exposure, PFOS isomer profiles (quantified as percent branched PFOS, %br-PFOS) and chiral 1m-PFOS enantiomer fractions (1m-PFOS EF) were analyzed in archived human serum samples of individual American adults (1974-2010) and pooled samples of Swedish primiparous women (1996-2010). After correcting for potential confounders, significant correlations between %br-PFOS and 1m-PFOS EFs were observed in American samples and in Swedish samples for the 1996-2000 period, supporting the hypothesis that both %br-PFOS and 1m-PFOS EF are biomarkers of PreFOS exposure. Significant trends of increasing %br-PFOS, from 2000 to 2010, and increasingly non-racemic 1m-PFOS EFs, from 1996 to 2000, were detected in Swedish samples. No statistically significant trend for %br-PFOS or 1m-PFOS EF was observed in American samples, but American males had significantly higher %br-PFOS and significantly lower 1m-PFOS EF (i.e. more non-racemic) than females, and a similar significant difference was shown in the older age group, relative to the younger age group. These temporal trends in %br-PFOS and 1m-PFOS EF are not easily explained and the results highlight uncertainties about how humans are exposed to PFOS. PMID:25490284

  12. Catchment controls on soil moisture dynamics: from site-specific hysteresis in event responses to temporal stability of patterns

    NASA Astrophysics Data System (ADS)

    Hassler, Sibylle K.; Weiler, Markus; Blume, Theresa

    2015-04-01

    Understanding soil moisture dynamics is a prerequisite for predicting hydrological response at the hillslope and catchment scale. Soil moisture is not only determined by its input characteristics such as rainfall, its redistribution by vegetation and evapotranspiration. Catchment characteristics resulting from the interplay of geology, topography, land cover and associated soil hydraulic properties also affect the distribution, storage and transport of water in the vadose zone. Successful process predictions and appropriate hydrological model structures thus rely on a good representation of soil moisture patterns and dynamics and benefit from insights into their dependence on catchment characteristics. In a unique measurement setup at the CAOS hydrological observatory in Luxemburg (http://www.caos-project.de) we record hydro-meteorological variables at 45 sensor cluster sites. These sites are distributed across the mesoscale Attert catchment and cover three different geological units (schist, marls and sandstone), two types of land use (forest and grassland), different topographical positions (up- and downslope with north- and south-facing aspects as well as plateau and floodplain locations). At each sensor cluster, each covering approximately an area of 30 m², soil moisture is measured in three profiles at three different depths, in piezometers groundwater levels are recorded, and rain gauges collect throughfall or gross precipitation. At near-stream locations we also measure stream water levels. This extensive sensor network enables us to study the influence of geology, land use and topography on soil moisture dynamics. In this study we focus on short-term hysteretic responses related to individual rainfall events and on longer-term temporal stability of soil moisture patterns. Similarities in the hysteresis loops of rainfall/soil moisture, soil moisture/groundwater levels and soil moisture/stream water levels can give some indication of the dominant catchment controls on storage and flow path activation. Examining the temporal stability of soil moisture patterns then helps to estimate the importance of these plot- and hillslope-scale hydrological processes on catchment-scale longer-term soil moisture dynamics. First results of the event-based analyses indicate differences in thresholds of the soil moisture response to rainfall events as an effect of land use. These thresholds are also dependent on the actual soil moisture state and rainfall event characteristics. Longer-term soil moisture patterns seem to be affected by both land use and topographic controls. Further should enable a more comprehensive assessment of the catchment controls on soil moisture.

  13. Spatio-temporal expression pattern of receptors for myelin-associated inhibitors in the developing rat olfactory system.

    PubMed

    Richard, Marion; Sacquet, Joëlle; Jourdan, François; Pellier-Monnin, Véronique

    2009-02-01

    The myelin-associated inhibitory proteins (Nogo-A, MAG and OMgp) that prevent axon regeneration in adult CNS, mediate their effects via a receptor referred as NgR1. Beside their inhibitory role in the adult CNS, Nogo-A and NgR1 might also be functionally involved in the developing nervous system. At the present time, no detailed study is available regarding either the onset of NgR1 expression during development or its spatio-temporal pattern of expression relative to the presence of Nogo-A. Two homologs of NgR1, NgR2 and NgR3, have been recently identified, but their function in the nervous system is still unknown in adult as well as during development. We have examined the spatio-temporal expression pattern of both NgR1, NgR2 and NgR3 mRNAs and corresponding proteins in the developing rat olfactory system using in situ hybridization and immunohistochemistry. From E15-E16 onwards, NgR1 mRNA was expressed by differentiating neurons in both the olfactory epithelium and the olfactory bulb. At all developmental stages, including adult animals, NgR1 protein was preferentially targeted to olfactory axons emerging from the olfactory epithelium. Using double-immunostainings in the postnatal olfactory mucosa, we confirm the neuronal localization of NgR1 and its preferential distribution along the olfactory axons. The NgR2 and NgR3 transcripts and their proteins display similar expression profiles in the olfactory system. Together, our data suggest that, in non-pathological conditions, NgR1 and its homologs may play a role in axon outgrowth in the rat olfactory system and may be relevant for the confinement of neural projections within the developing olfactory bulb. PMID:19063867

  14. Daily Temporal Patterns of Heroin and Cocaine Use and Craving: Relationship with Business Hours Regardless of Actual Employment Status

    PubMed Central

    Phillips, Karran A.; Epstein, David H.; Preston, Kenzie L.

    2013-01-01

    Real-time monitoring of behavior using Ecological Momentary Assessment (EMA) has provided detailed data about daily temporal patterns of craving and use in cigarette smokers. We have collected similar data from a sample of cocaine and heroin users. Here we analyzed it in the context of its relationship with a societal construct of daily temporal organization: 9-to-5 business hours. In a 28-week prospective study, 112 methadone-maintained polydrug-abusing individuals initiated an electronic-diary entry and provided data each time they used cocaine, heroin, or both during weeks 4 to 28. EMA data were collected for 10,781 person-days and included: 663 cocaine-craving events, 710 cocaine-use events, 288 heroin-craving events, 66 heroin-use events, 630 craving-both-drugs events, and 282 use-of-both-drugs events. At baseline, 34% of the participants reported full-time employment in the preceding 3-year period. Most participants’ current employment status fluctuated throughout the study. In a generalized linear mixed model (SAS Proc Glimmix), cocaine use varied by time of day relative to business hours (p<0.0001) and there was a significant interaction between Day of the Week and Time Relative to Business Hours (p<0.002) regardless of current work status. Cocaine craving also varied by time of day relative to business hours (p<0.0001), however, there was no significant interaction between Day of the Week and Time Relative to Business Hours (p=.57). Heroin craving and use were mostly reported during business hours, but data were sparse. Cocaine craving is most frequent during business hours while cocaine use is more frequent after business hours. Cocaine use during business hours, but not craving, seems suppressed on most weekdays, but not weekends, suggesting that societal conventions reflected in business hours influence drug-use patterns even in individuals whose daily schedules are not necessarily dictated by employment during conventional business hours. PMID:23770647

  15. Temporal patterns of diversity: Assessing the biotic and abiotic controls on ant assemblages

    USGS Publications Warehouse

    Dunn, R.R.; Parker, C.R.; Sanders, N.J.

    2007-01-01

    In this study, we use 12 months of data from 11 ant assemblages to test whether seasonal variation in ant diversity is governed by either the structuring influences of interspecific competition or environmental conditions. Because the importance of competition might vary along environmental gradients, we also test whether the signature of competition depends on elevation. We find little evidence that competition structures the seasonal patterns of activity in the ant assemblages considered, but find support for the effects of temperature on seasonal patterns of diversity, especially at low-elevation sites. Although, in general, both competition and the environment interact to structure ant assemblages, our results suggest that environmental conditions are the primary force structuring the seasonal activity of the ant assemblages studied here. ?? 2007 The Linnean Society of London.

  16. Discovering and Predicting Temporal Patterns of WiFi-interactive Social Populations

    E-print Network

    Li, Xiang; Vasilakos, Athanasios V

    2014-01-01

    Extensive efforts have been devoted to characterizing the rich connectivity patterns among the nodes (components) of such complex networks (systems), and in the course of development of research in this area, people have been prompted to address on a fundamental question: How does the fascinating yet complex topological features of a network affect or determine the collective behavior and performance of the networked system? While elegant attempts to address this core issue have been made, for example, from the viewpoints of synchronization, epidemics, evolutionary cooperation, and the control of complex networks, theoretically or empirically, this widely concerned key question still remains open in the newly emergent field of network science. Such fruitful advances also push the desire to understand (mobile) social networks and characterize human social populations with the interdependent collective dynamics as well as the behavioral patterns. Nowadays, a great deal of digital technologies are unobtrusively ...

  17. Complaints and Annoyance caused by Aircraft Operations: Temporal Patterns and Individual Bias.

    PubMed

    Hume, Ken; Terranova, Daniela; Thomas, Callum

    2002-01-01

    The impact of aircraft movements on annoyance in the local community surrounding a major international airport was assessed for (a) patterns of complaints for the year, month, day-of-the-week and time-of-day and (b) the frequency of complaining by individuals. Complaint data from Manchester Airport since 1991 and detailed analysis for 1998 were compared with associated information on noise monitoring and aircraft movements to investigate underlying biological and sociological patterns. The annual number of complaints peaked in 1996 when the 'Manchester Airport Second Runway Public Inquiry' was a major local issue and had a high profile in the local media. Since 1996 the number of flights has increased while the number of complaints has steadily fallen; from 50 to13 complaints per 1,000 movements from 1996 to 1999. Detailed inspection of the 1998 data revealed a total of 2072 noise complaints from 594 individuals but, while the majority of individuals complained once or twice, three individuals accounted for 41% of complaints. This introduced some bias into the results but there was; (a) a steady increase in complaints (per 1,000 movements) over the week from a low on Monday to a high on Saturday/Sunday; (b) a marked hourly variation over the 24 hours in both flight frequency (movements per hour) and complaints. However, the hourly patterns in flight frequency and complaints were clearly distinct. Calculations of the complaints per aircraft movement (a reflection of sensitivity) for each hour of the day showed a striking 24h pattern with twice as many complaints between 23.00 and 07.00 as the rest of the day (07.00-23.00). Late evening and night-time, particularly during the early hours of sleep, was the time of greatest sensitivity to aircraft, with or without the serial complainers. These results could be used to inform airport operations to minimize community disturbance. PMID:12678948

  18. Spatial and Temporal Patterns of Stranded Intertidal Marine Debris: Is There a Picture of Global Change?

    PubMed

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

    2015-06-16

    Floating and stranded marine debris is widespread. Increasing sea levels and altered rainfall, solar radiation, wind speed, waves, and oceanic currents associated with climatic change are likely to transfer more debris from coastal cities into marine and coastal habitats. Marine debris causes economic and ecological impacts, but understanding the scope of these requires quantitative information on spatial patterns and trends in the amounts and types of debris at a global scale. There are very few large-scale programs to measure debris, but many peer-reviewed and published scientific studies of marine debris describe local patterns. Unfortunately, methods of defining debris, sampling, and interpreting patterns in space or time vary considerably among studies, yet if data could be synthesized across studies, a global picture of the problem may be avaliable. We analyzed 104 published scientific papers on marine debris in order to determine how to evaluate this. Although many studies were well designed to answer specific questions, definitions of what constitutes marine debris, the methods used to measure, and the scale of the scope of the studies means that no general picture can emerge from this wealth of data. These problems are detailed to guide future studies and guidelines provided to enable the collection of more comparable data to better manage this growing problem. PMID:25938368

  19. Temporal cues derived from statistical patterns can overcome resource limitations in the attentional blink.

    PubMed

    Visser, Troy A W; Ohan, Jeneva L; Enns, James T

    2015-07-01

    Previous studies have shown that humans are sensitive to statistical patterns indicating the likely locations, identities, and timings of visual targets. Here we tested whether participants can also use this kind of information to ameliorate the attentional blink (AB)-a reduction in accuracy for the second of two targets (T1, T2) presented at brief intertarget intervals (lags). In particular, we asked whether participants can use patterns arising from differential distributions of intertarget lags across trials to predict the arrival of T2. We tested this by comparing the ABs in an aging versus a nonaging distribution of trials, where aging refers to the increased likelihood of T2, given that it has not yet occurred, when lags occur with equal frequencies. Experiments 1 and 2 showed that the aging condition yielded greater T2 accuracy at longer lags than did the nonaging condition. In Experiment 3, we used a more sensitive response time measure to show faster T2 discrimination at shorter lags in the nonaging condition. These results demonstrate that participants can predict the likely onset of T2 by using statistical patterns present in the AB task, and that they can use this ability to more effectively direct limited processing resources. PMID:25813742

  20. Mountain chickadees from different elevations sing different songs: acoustic adaptation, temporal drift or signal of local adaptation?

    PubMed

    Branch, Carrie L; Pravosudov, Vladimir V

    2015-04-01

    Song in songbirds is widely thought to function in mate choice and male-male competition. Song is also phenotypically plastic and typically learned from local adults; therefore, it varies across geographical space and can serve as a cue for an individual's location of origin, with females commonly preferring males from their respective location. Geographical variation in song dialect may reflect acoustic adaptation to different environments and/or serve as a signal of local adaptation. In montane environments, environmental differences can occur over an elevation gradient, favouring local adaptations across small spatial scales. We tested whether food caching mountain chickadees, known to exhibit elevation-related differences in food caching intensity, spatial memory and the hippocampus, also sing different dialects despite continuous distribution and close proximity. Male songs were collected from high and low elevations at two different mountains (separated by 35 km) to test whether song differs between elevations and/or between adjacent populations at each mountain. Song structure varied significantly between high and low elevation adjacent populations from the same mountain and between populations from different mountains at the same elevations, despite a continuous distribution across each mountain slope. These results suggest that elevation-related differences in song structure in chickadees might serve as a signal for local adaptation. PMID:26064641

  1. Mountain chickadees from different elevations sing different songs: acoustic adaptation, temporal drift or signal of local adaptation?

    PubMed Central

    Branch, Carrie L.; Pravosudov, Vladimir V.

    2015-01-01

    Song in songbirds is widely thought to function in mate choice and male–male competition. Song is also phenotypically plastic and typically learned from local adults; therefore, it varies across geographical space and can serve as a cue for an individual's location of origin, with females commonly preferring males from their respective location. Geographical variation in song dialect may reflect acoustic adaptation to different environments and/or serve as a signal of local adaptation. In montane environments, environmental differences can occur over an elevation gradient, favouring local adaptations across small spatial scales. We tested whether food caching mountain chickadees, known to exhibit elevation-related differences in food caching intensity, spatial memory and the hippocampus, also sing different dialects despite continuous distribution and close proximity. Male songs were collected from high and low elevations at two different mountains (separated by 35 km) to test whether song differs between elevations and/or between adjacent populations at each mountain. Song structure varied significantly between high and low elevation adjacent populations from the same mountain and between populations from different mountains at the same elevations, despite a continuous distribution across each mountain slope. These results suggest that elevation-related differences in song structure in chickadees might serve as a signal for local adaptation.

  2. Spatio-Temporal Patterns of Beaked Whale Echolocation Signals in the North Pacific

    PubMed Central

    Baumann-Pickering, Simone; Roch, Marie A.; Brownell Jr, Robert L.; Simonis, Anne E.; McDonald, Mark A.; Solsona-Berga, Alba; Oleson, Erin M.; Wiggins, Sean M.; Hildebrand, John A.

    2014-01-01

    At least ten species of beaked whales inhabit the North Pacific, but little is known about their abundance, ecology, and behavior, as they are elusive and difficult to distinguish visually at sea. Six of these species produce known species-specific frequency modulated (FM) echolocation pulses: Baird’s, Blainville’s, Cuvier’s, Deraniyagala’s, Longman’s, and Stejneger’s beaked whales. Additionally, one described FM pulse (BWC) from Cross Seamount, Hawai’i, and three unknown FM pulse types (BW40, BW43, BW70) have been identified from almost 11 cumulative years of autonomous recordings at 24 sites throughout the North Pacific. Most sites had a dominant FM pulse type with other types being either absent or limited. There was not a strong seasonal influence on the occurrence of these signals at any site, but longer time series may reveal smaller, consistent fluctuations. Only the species producing BWC signals, detected throughout the Pacific Islands region, consistently showed a diel cycle with nocturnal foraging. By comparing stranding and sighting information with acoustic findings, we hypothesize that BWC signals are produced by ginkgo-toothed beaked whales. BW43 signal encounters were restricted to Southern California and may be produced by Perrin’s beaked whale, known only from Californian waters. BW70 signals were detected in the southern Gulf of California, which is prime habitat for Pygmy beaked whales. Hubb’s beaked whale may have produced the BW40 signals encountered off central and southern California; however, these signals were also recorded off Pearl and Hermes Reef and Wake Atoll, which are well south of their known range. PMID:24465877

  3. Acoustic Analyses and Intelligibility Assessments of Timing Patterns Among Chinese English Learners with Different Dialect Backgrounds.

    PubMed

    Chen, Hsueh Chu

    2014-09-01

    This paper includes two interrelated studies. The first production study investigates the timing patterns of English as spoken by Chinese learners with different dialect backgrounds. The second comprehension study explores native and non-native speakers' assessments of the intelligibility of Chinese-accented English, and examines the effects of the listeners' language backgrounds on their perceptions of Chinese-accented English. The results showed that the Hong Kong (HK) group performed better in unstressed syllable duration compared with the Taiwan (TW) and Beijing (BJ) groups. The results also revealed that all six listener groups achieved at least 78 % intelligibility, with the native speaker accent achieving the highest rating, followed by the HK, TW, and BJ accents. A shared first language (L1) background may have little or no impact on intelligibility. The speech properties might prevail over the shared L1 effect. All listeners perceived inappropriate word-stress shift and consonant cluster simplifications to be the most unintelligible features. PMID:25194949

  4. Temporal and spatial pattern of embolism induced by pressure collar techniques in twigs of Picea abies.

    PubMed

    Mayr, Stefan; Rothart, Barbara; Wolfschwenger, Marion

    2006-01-01

    The pressure collar technique enables the induction of embolism in plant xylem. This artificial cavitation is based on air seeding processes which occur when specific pressure gradients between the air and water phase of the xylem are exceeded. Standard pressure collars and a new point injection technique, which builds up a local potential gradient, were used to study the time and spatial pattern of this process. On twigs of Norway spruce (Picea abies), the cross-sectional and axial pattern, and the time-course of embolism formation were analysed via conductivity and ultrasonic measurements as well as staining experiments. Furthermore, the release of air from the twig surface was studied by immersing twig sections in water. In cross-sections, embolized areas induced by the point injection technique were smaller compared with the standard collar and restricted to a circle sector. Embolism propagated from the pressure collar towards the nearest distal and proximal nodes but not further. A release of air was also observed predominantly at the internode attached to the pressure collar. Embolism rates increased within minutes and reached approximately 80% loss of conductivity after 10 min treatment with the standard collar. The size of air entry points and embolism rates correlated significantly. Embolism formation in wood therefore depends not only on vulnerability thresholds but also on the extent of air-water interfaces within the xylem and on the time of exposure to pressure gradients. These aspects and the propagation of pressure within samples are crucial for pressure collar experiments. In addition, wood architecture influences the extent and pattern of embolism caused by air seeding processes. PMID:16882643

  5. Temporal patterns of surface ozone levels in different habitats of the North Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Ribas, Àngela; Peñuelas, Josep

    A systematic temporal analysis of surface ozone observations in four sites representative of the main types of habitats: coast, mountain, inland and urban in the North Western Mediterranean basin is presented here for the period between 1994 and 2001. Concentrations were relatively high, especially in the coastal site where the European human and plant protection thresholds were surpassed an average of 54 and 297 days per year, respectively. We observed a 22% decrease in the ozone concentrations along the past decade in the coastal site, a 14% increase in the mountain site, and no significant change in the inland and urban sites. The annual cycle of ozone in the coastal site (maximum concentrations in spring) was typical of areas with higher influences of background ozone, whereas in the other sites, the broad spring-summer maximum indicated dominance of local photochemical production. The site differences were also evident in their diurnal cycles, which were very evident in all sites except in the coastal one. There was thus significant variability among the monitoring sites, due to both the influence of local and background sources and the complex orographic and meteorological conditions of this region.

  6. Spatio-temporal patterns of stratification on the Northwest Atlantic shelf

    NASA Astrophysics Data System (ADS)

    Li, Yun; Fratantoni, Paula S.; Chen, Changsheng; Hare, Jonathan A.; Sun, Yunfang; Beardsley, Robert C.; Ji, Rubao

    2015-05-01

    A spatially explicit stratification climatology is constructed for the Northwest Atlantic continental shelf using daily averaged hydrographic fields from a 33-year high-resolution, data-assimilated reanalysis dataset. The high-resolution climatology reveals considerable spatio-temporal heterogeneity in seasonal variability with strong interplay between thermal and haline processes. Regional differences in the magnitude and phasing of the seasonal cycle feature earlier development/breakdown in the Middle Atlantic Bight (MAB) and larger peaks on the shelf than in the Gulf of Maine (GoM). The relative contribution of the thermal and haline components to the overall stratification is quantified using a novel diagram composed of two key ratios. The first relates the vertical temperature gradient to the vertical salinity gradient, and the second relates the thermal expansion coefficient to the haline contraction coefficient. Two distinct regimes are identified: the MAB region is thermally-dominated through a larger portion of the year, whereas the Nova Scotian Shelf and the eastern GoM have a tendency towards haline control during the year. The timing of peak stratification and the beginning/end of thermally-positive and thermally-dominant states are examined. Their spatial distributions indicate a prominent latitudinal shift and regionality, having implications for the seasonal cycle of ecosystem dynamics and its interannual variability.

  7. Macroinvertebrates Associated With Dikes in the Mississippi River: Spatial and Temporal Patterns

    NASA Astrophysics Data System (ADS)

    Battle, J.; Jackson, J. K.; Sweeney, B. W.

    2005-05-01

    Fine sediments and rocky substrates are dominant benthic macroinvertebrate habitats in the Mississippi River. We sampled macroinvertebrates in fine sediments downstream of wing dikes on four occasions and on rocks upstream of wing dikes on two occasions. We identified 65 taxa in the fine sediments and 50 taxa on the rocks, with only 26 taxa found in both habitats. Presumably, assemblage differences reflect flow and substrate differences. Assemblages in both habitats exhibited considerable temporal variability. Macroinvertebrate densities in the fine sediments ranged from 3737 to 8706 individuals m-2 y-1, with oligochaetes representing 77-92% of total density. Macroinvertebrate density on the rocks ranged from 57,770 to 162,966 individuals m-2 y-1, with hydropsychid caddisflies (Hydropsyche bidens/orris and Potamyia flava) representing 82-97% of total density. A literature survey found that macroinvertebrate assemblages in large rivers of the Mississippi River Basin (e.g., Upper and Lower Mississippi, Illinois, Ohio, and Missouri Rivers) tend to be dominated by a few taxa. Because of this, we believe that traditional approaches to describing community structure (e.g., species richness, relative abundance) in biological assessments may be insensitive to subtle differences among large river faunas.

  8. Temporal and spatial patterns in recruitment of three penaeid prawns in Moreton Bay, Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Courtney, A. J.; Masel, J. M.; Die, D. J.

    1995-10-01

    The size at recruitment, temporal and spatial distribution, and abiotic factors influencing abundance of three commercially important species of penaeid prawns in the sublittoral trawl grounds of Moreton Bay (Queensland, Australia) were compared. Metapenaeus bennettae and Penaeus plebejus recruit to the trawl grounds at sizes which are relatively small (14-15 mm carapace length, CL) and below that at which prawns are selected for, and retained, in the fleet's cod-ends. In contrast, Penaeus esculentus recruit at the relatively large size of 27 mm CL from February to May, well above the size ranges selected for. Recruitment of M. bennettae extends over several months, September-October and February-March, and was thus likely to be bi-annual, while the recruitment period of P. plebejus was distinct, peaking in October-November each year. Size classes of M. bennettae were the most spatially stratified of the three species. Catch rates of recruits were negatively correlated with depth for all three species, and were also negatively correlated with salinity for M. bennettae.

  9. Patterns of cyto-nuclear linkage disequilibrium in Silene latifolia: genomic heterogeneity and temporal stability.

    PubMed

    Fields, P D; McCauley, D E; McAssey, E V; Taylor, D R

    2014-02-01

    Non-random association of alleles in the nucleus and cytoplasmic organelles, or cyto-nuclear linkage disequilibrium (LD), is both an important component of a number of evolutionary processes and a statistical indicator of others. The evolutionary significance of cyto-nuclear LD will depend on both its magnitude and how stable those associations are through time. Here, we use a longitudinal population genetic data set to explore the magnitude and temporal dynamics of cyto-nuclear disequilibria through time. We genotyped 135 and 170 individuals from 16 and 17 patches of the plant species Silene latifolia in Southwestern VA, sampled in 1993 and 2008, respectively. Individuals were genotyped at 14 highly polymorphic microsatellite markers and a single-nucleotide polymorphism (SNP) in the mitochondrial gene, atp1. Normalized LD (D') between nuclear and cytoplasmic loci varied considerably depending on which nuclear locus was considered (ranging from 0.005-0.632). Four of the 14 cyto-nuclear associations showed a statistically significant shift over approximately seven generations. However, the overall magnitude of this disequilibrium was largely stable over time. The observed origin and stability of cyto-nuclear LD is most likely caused by the slow admixture between anciently diverged lineages within the species' newly invaded range, and the local spatial structure and metapopulation dynamics that are known to structure genetic variation in this system. PMID:24002238

  10. Spatial and Temporal Patterns of Apparent Electrical Conductivity: DUALEM vs. Veris Sensors for Monitoring Soil Properties

    PubMed Central

    Serrano, João; Shahidian, Shakib; da Silva, José Marques

    2014-01-01

    The main objective of this study was to compare two apparent soil electrical conductivity (ECa) sensors (Veris 2000 XA and DUALEM 1S) for mapping variability of soil properties in a Mediterranean shallow soil. This study also aims at studying the effect of soil cover vegetation on the ECa measurement by the two types of sensors. The study was based on two surveys carried out under two very different situations: in February of 2012, with low soil moisture content (SMC) and with high and differentiated vegetation development (non grazed pasture), and in February of 2013, with high SMC and with short and relatively homogeneous vegetation development (grazed pasture). The greater temporal stability of Veris sensor, despite the wide variation in the SMC and vegetation ground cover indicates the suitability of using this sensor for monitoring soil properties in permanent pastures. The survey carried out with the DUALEM sensor in 2012 might have been affected by the presence of a 0.20 m vegetation layer at the soil surface, masking the soil properties. These differences should be considered in the selection of ECa sensing systems for a particular application. PMID:24915182

  11. Patterns of cyto-nuclear linkage disequilibrium in Silene latifolia: genomic heterogeneity and temporal stability

    PubMed Central

    Fields, P D; McCauley, D E; McAssey, E V; Taylor, D R

    2014-01-01

    Non-random association of alleles in the nucleus and cytoplasmic organelles, or cyto-nuclear linkage disequilibrium (LD), is both an important component of a number of evolutionary processes and a statistical indicator of others. The evolutionary significance of cyto-nuclear LD will depend on both its magnitude and how stable those associations are through time. Here, we use a longitudinal population genetic data set to explore the magnitude and temporal dynamics of cyto-nuclear disequilibria through time. We genotyped 135 and 170 individuals from 16 and 17 patches of the plant species Silene latifolia in Southwestern VA, sampled in 1993 and 2008, respectively. Individuals were genotyped at 14 highly polymorphic microsatellite markers and a single-nucleotide polymorphism (SNP) in the mitochondrial gene, atp1. Normalized LD (D?) between nuclear and cytoplasmic loci varied considerably depending on which nuclear locus was considered (ranging from 0.005–0.632). Four of the 14 cyto-nuclear associations showed a statistically significant shift over approximately seven generations. However, the overall magnitude of this disequilibrium was largely stable over time. The observed origin and stability of cyto-nuclear LD is most likely caused by the slow admixture between anciently diverged lineages within the species' newly invaded range, and the local spatial structure and metapopulation dynamics that are known to structure genetic variation in this system. PMID:24002238

  12. Temporal Patterns of Happiness and Information in a Global Social Network: Hedonometrics and Twitter

    PubMed Central

    Dodds, Peter Sheridan; Harris, Kameron Decker; Kloumann, Isabel M.; Bliss, Catherine A.; Danforth, Christopher M.

    2011-01-01

    Individual happiness is a fundamental societal metric. Normally measured through self-report, happiness has often been indirectly characterized and overshadowed by more readily quantifiable economic indicators such as gross domestic product. Here, we examine expressions made on the online, global microblog and social networking service Twitter, uncovering and explaining temporal variations in happiness and information levels over timescales ranging from hours to years. Our data set comprises over 46 billion words contained in nearly 4.6 billion expressions posted over a 33 month span by over 63 million unique users. In measuring happiness, we construct a tunable, real-time, remote-sensing, and non-invasive, text-based hedonometer. In building our metric, made available with this paper, we conducted a survey to obtain happiness evaluations of over 10,000 individual words, representing a tenfold size improvement over similar existing word sets. Rather than being ad hoc, our word list is chosen solely by frequency of usage, and we show how a highly robust and tunable metric can be constructed and defended. PMID:22163266

  13. Phytoplankton blooms in the Ross Sea, Antarctica: Interannual variability in magnitude, temporal patterns, and composition

    NASA Astrophysics Data System (ADS)

    Peloquin, Jill A.; Smith, Walker O.

    2007-08-01

    The continental shelf of the Ross Sea, Antarctica, is a unique region within the Southern Ocean. Phytoplankton growth is believed to be seasonally limited, first in austral spring by irradiance, and then in summer by biologically available iron. It also is historically known to have taxonomically distinct regimes: the south-central portion is dominated by Phaeocystis antarctica and to the west diatoms are abundant. We measured photochemical yield to interpret the health of the phytoplankton assemblage from 2001-2004 and interfaced these measurements with satellite remote sensing of pigments. The bloom of 2001-2002 was similar in both temporal and spatial distributions to the climatological mean of the Ross Sea, with a peak in biomass being observed in mid-December within the Ross Sea polynyas; Fv/Fm values averaged 0.43. We found high (0.50-0.65) Fv/Fm for most of the seasonal phytoplankton bloom for 2002-2003, suggesting that it was not seasonally iron limited. An unusual, large bloom occurred during 2003-2004, with an initial bloom of P. antarctica during austral spring followed by an extensive diatom bloom in summer that may have been enhanced by an intrusion of modified circumpolar deep water. On the basis of an analysis of the historical SeaWiFS records, accumulation of phytoplankton biomass in February may occur approximately every 2-4 years, potentially being a significant source of carbon on the continental shelf.

  14. Developmental Trajectories of Emotion Regulation Across Infancy: Do Age and the Social Partner Influence Temporal Patterns?

    PubMed Central

    Ekas, Naomi V.; Lickenbrock, Diane M.; Braungart-Rieker, Julia M.

    2012-01-01

    The ability to effectively regulate emotions is a critical component of early socio-emotional development. This longitudinal study examined the developmental trajectories of emotion regulation in a sample of 3-, 5-, and 7-month-olds during an interaction with mothers and fathers. Infants’ negative affect and use of behavioral strategies, including distraction, self-soothing, and high intensity motor behaviors were rated during the still-face episode of the Still-Face Paradigm. Longitudinal mixed-effects models were tested to determine whether strategies were followed by an increase or decrease in negative affect. Results from mother-infant and father-infant dyads indicated that focusing attention away from the unresponsive parent and engaging in self-soothing behaviors were associated with a subsequent decline in negative affect and the strength of these temporal associations were stable across infancy. In contrast, high-intensity motor behaviors were followed by an increase in negative affect and this effect declined over time. No significant effects were found for the behavioral strategy of looking at the parent. Results underscore the importance of considering infant age and the social partner when studying the effectiveness of emotion regulatory strategies in early infancy. PMID:24244107

  15. Multivoxel patterns in face-sensitive temporal regions reveal an encoding schema based on detecting life in a face.

    PubMed

    Looser, Christine E; Guntupalli, Jyothi S; Wheatley, Thalia

    2013-10-01

    More than a decade of research has demonstrated that faces evoke prioritized processing in a 'core face network' of three brain regions. However, whether these regions prioritize the detection of global facial form (shared by humans and mannequins) or the detection of life in a face has remained unclear. Here, we dissociate form-based and animacy-based encoding of faces by using animate and inanimate faces with human form (humans, mannequins) and dog form (real dogs, toy dogs). We used multivariate pattern analysis of BOLD responses to uncover the representational similarity space for each area in the core face network. Here, we show that only responses in the inferior occipital gyrus are organized by global facial form alone (human vs dog) while animacy becomes an additional organizational priority in later face-processing regions: the lateral fusiform gyri (latFG) and right superior temporal sulcus. Additionally, patterns evoked by human faces were maximally distinct from all other face categories in the latFG and parts of the extended face perception system. These results suggest that once a face configuration is perceived, faces are further scrutinized for whether the face is alive and worthy of social cognitive resources. PMID:22798395

  16. Temporal dynamics of salt crust patterns on a sodic playa: implications for aerodynamic roughness and dust emission potential

    NASA Astrophysics Data System (ADS)

    Nield, Joanna; Bryant, Robert; Wiggs, Giles; King, James; Thomas, David; Eckardt, Frank; Washington, Richard

    2015-04-01

    Salt pans (or playas) are common in arid environments and can be major sources of windblown mineral dust, but there are uncertainties associated with their dust emission potential. These landforms typically form crusts which modify both their erosivity and erodibility by limiting sediment availability, modifying surface and aerodynamic roughness and limiting evaporation rates and sediment production. Here we show the relationship between seasonal surface moisture change and crust pattern development on part of the Makgadikgadi Pans of Botswana (a Southern Hemisphere playa that emits significant dust), based on both remote-sensing and field surface and atmospheric measurements. We use high resolution (sub-cm) terrestrial laser scanning (TLS) surveys over weekly, monthly and annual timescales to accurately characterise crustal ridge thrusting and collapse. Ridge development can change surface topography as much as 30 mm/week on fresh pan areas that have recently been reset by flooding. The corresponding change aerodynamic roughness can be as much as 3 mm/week. At the same time, crack densities across the surface increase and this raises the availability of erodible fluffy, low density dust source sediment stored below the crust layer. We present a conceptual model accounting for the driving forces (subsurface, surface and atmospheric moisture) and feedbacks between these and surface shape that lead to crust pattern trajectories between highly emissive degraded surfaces and less emissive ridged or continuous crusts. These findings improve our understanding of temporal changes in dust availability and supply from playa source regions.

  17. Understanding the spatial and temporal patterns of copper in-use stocks in china.

    PubMed

    Zhang, Ling; Yang, Jiameng; Cai, Zhijian; Yuan, Zengwei

    2015-06-01

    Two approaches are adopted to characterize the comprehensive pattern of the copper in-use stocks in China. The top-down results indicate that both the total amount and the per capita quantity of the stocks have exhibited a significant and increasing trend for the past 60 years, especially since 2000. The top-down results show that the copper stocks increased from a negligible level of less than 1 kg/capita in 1952 to 44 kg/capita in 2012. The total stocks in 2012 are estimated to be 60 Mt by a top-down approach or 48 Mt by a bottom-up calculation. The bottom-up method determines that the largest reservoir is the infrastructure sector, which accounts for approximately 58% of the total stocks. The spatial pattern indicates that the copper in-use stocks are predominately spatially distributed in the eastern regions of China, a feature that is obviously different from the geographical distribution of the primary resources. Analysis on the prospects of stocks shows both the total magnitude and per capita value will continuously increase in the following decade, and enter a relatively stable stage in around 2030, with a maximum value of 106 kg/capita. The results improve the knowledge about closing copper cycles. PMID:25927890

  18. Spatial and temporal patterns of throughfall chemistry within a temperate mixed oak-beech stand.

    PubMed

    André, Frédéric; Jonard, Mathieu; Ponette, Quentin

    2008-07-01

    The effects of meteorological variables and local canopy characteristics on throughfall chemistry were investigated within a mixed oak-beech stand during the leafed and the leafless seasons. Throughfall was collected after each rain event in 12 structural units delimited by three neighbouring trees each. For each investigated ion (H+, Mg2+, Ca2+, K+, NH4+, Na+, Cl(-), NO3(-) and SO4(2-)), mixed linear models were used to analyse the effects of the rain volume (R) and of the length of the preceding dry period (ADP) on net throughfall ion fluxes and to evaluate the influence of canopy density and tree species composition on these relationships. The models explained more than 70% of the total variability. Canopy characteristics accounted for most of the spatial variability while a large part of the temporal variability was not explained by R and ADP, suggesting an influence of other variables such as wind force and direction. For each season, net throughfall ion fluxes generally increased with increasing R and ADP, whose coefficients were interpreted as leaching capacity and dry deposition rate, respectively; H+ is an exception with negative exchange capacity (i.e. absorption) during the leafed season. Dry deposition rate and exchange capacity estimates were generally lower for the leafless canopies compared with the leafed season. For a given density level, exchange capacities were either higher for oak than for beech or similar for both species while dry deposition tended to increase with increasing beech proportion. The enhancing effect of canopy density on dry deposition was particularly marked for the mixed leafed canopies. For the pure canopies, the effect of canopy density on dry deposition rate and exchange capacity tended to be more pronounced during the leafless period compared with the leafed season, while it was generally limited compared with the species effect. PMID:18403000

  19. Identification of Damaged Wheat Kernels and Cracked-Shell Hazelnuts with Impact Acoustics Time-Frequency Patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new adaptive time-frequency (t-f) analysis and classification procedure is applied to impact acoustic signals for detecting hazelnuts with cracked shells and three types of damaged wheat kernels. Kernels were dropped onto a steel plate, and the resulting impact acoustic signals were recorded with ...

  20. Temporal and spatial patterns of late Pleistocene-Holocene faulting in Arizona

    SciTech Connect

    Menges, C.M. (Geological Survey, Las Vegas, NV (United States)); Pearthree, P.A. (Arizona Geological Survey, Tucson, AZ (United States))

    1993-04-01

    Geomorphic and geologic analyses of Quaternary faults in Arizona and adjoining areas conducted in the past 15 years have revealed the general patterns of late Pleistocene and Holocene (< 150 ka) faulting. Nearly all of the late Quaternary faults in Arizona are located within a broad band stretching from northwest to southeast across the State. The greatest density of late Quaternary faults is found along the Basin and Range-Colorado Plateau transition in central and northwestern Arizona; a lesser concentration of these faults exists in the Mexican Highland portion of the Basin and Range in southeastern Arizona and southwestern New Mexico. Several active faults are located in southwestern Arizona, outside the main band of faulting. The band of late Quaternary faults in Arizona coincides with a zone of moderate historical seismicity. Studies of 15 individual fault zones provide more detailed information about the patterns of late Pleistocene and Holocene faulting in Arizona. These studies have involved geologic mapping, soils and stratigraphic analyses, morphologic fault scarp analyses, or trenching. The most active faults in Arizona, with recurrence intervals as short as 10,000--20,000 yrs, are found in the northwestern portion of the State. Faults in north-central and southwesternmost Arizona have somewhat longer recurrence intervals (ca. 20,000--50,000 yrs). Late Pleistocene and younger faulting (< 150 ka) has occurred in all areas where there is evidence of Quaternary faulting. Latest Pleistocene-Holocene faulting (< 20 ka) has occurred on 17--20 faults. These events are concentrated in several restricted belts in northwestern Arizona, central Arizona, and the border region between AZ, NM, and Sonora, Mex. Given the long recurrence intervals for individual faults in central and southeastern AZ, faulting in the past 20 k.y. may represent a burst of activity that is a low-strain analog of the historical burst of surface faulting in the central NV seismic belt.

  1. Temporal patterns in the epidemiology of schistosome infections of snails: a model for field data.

    PubMed

    Woolhouse, M E; Chandiwana, S K

    1990-04-01

    The prevalence of patent schistosome infections of intermediate host snails often shows seasonal variations. For schistosome, mainly Schistosoma haematobium, infections of Bulinus globosus field data from Zimbabwe show annual ranges in prevalence from 2% to 30%. In this paper a mathematical model is developed for B. globosus population dynamics and the epidemiology of schistosome infection. The model is a discrete-time analogue of a catalytic model, with an added recruitment term. Snail fecundity and survival are functions of age, infection, and temperature. The pre-patent period of infection is dependent on temperature. Parameter values, and relationships with temperature, are taken from earlier field and laboratory studies. The force-of-infection is estimated from analysis of age-prevalence data. Model predictions, making use of temperature data recorded in the field, are in good agreement with observations over a 2-year period at a study site in Zimbabwe. The key features of interest are a fall in the prevalence of patent infections during the cold season and a rapid rise to a peak early in the hot season. This pattern results from the accumulation of pre-patent infections which fail to develop at low temperatures, but mature en masse, together with new infections, after a few weeks at higher temperatures. Model analysis demonstrates that seasonal patterns in the prevalence of patent infections may be due largely to the influence of temperature on the pre-patent period. Seasonal and year-to-year variations in temperature may therefore have significant epidemiological effects. PMID:2345659

  2. Changing patterns of propagation in a super-refractory status of the temporal lobe. Over 900 seizures recorded over nearly one year?

    PubMed Central

    Napolitano, Cayetano E.; Orriols, Miguel A.

    2013-01-01

    Objective Our goals were to study the propagation models in a situation of persistent temporal epileptic seizures with varying degrees of bitemporal excitability and to analyze which propagation models were found at times of high temporal excitability and which occurred with lower levels of excitability. Methods A patient with super-refractory status arising from the temporal lobes was studied daily using video-electroencephalography (VEEG), with a large number of electroclinical seizures recorded. The analysis focused on the method and type of seizure propagation and classified them either according to the propagation models described in the literature or as undetermined. Results Video-EEG monitoring was carried out daily for 310 days. A total of 990 electroclinical seizures were recorded; 135 seizures were recorded during the first week, and 523 were recorded in the first month. From the beginning, the interictal recording showed independent discharges over both temporal lobes. The seizures showed independent onset in both temporal lobes. During periods of the highest number of seizures, certain models of propagation begin to predominate through switch of lateralization, temporal asynchrony, early remote propagation, total contralateral propagation, seizures with nonlocalized onset, or models that are difficult to classify. Conversely, when the condition was brought relatively under control, we observed fewer propagation models with predominantly simple patterns: only hemispheric propagation or graduated sequential propagation with a few nonlateralized onset seizures. Conclusions Upon analyzing the seizures, we found that the propagation models vary as the status evolved, with the change reflecting the degree of excitability in the mesial temporal–limbic network at a given time. In clinical practice, these changes in propagation models are more likely to be observed in temporal status that extends over time and with an onset of the seizures in both temporal lobes. Significance The analysis of the propagation models may provide information about the excitability of the mesial temporal–limbic network. PMID:25667845

  3. Temporal expression patterns of diapause-associated genes in flesh fly pupae from the onset of diapause through post-diapause quiescence

    Microsoft Academic Search

    S. A. L. Hayward; S. C. Pavlides; S. P. Tammariello; J. P. Rinehart; D. L. Denlinger

    2005-01-01

    Distinct differences in the temporal expression patterns of genes associated with pupal diapause were noted in the flesh fly, Sarcophaga crassipalpis. The first change observed was a decline in expression of the gene encoding heat shock protein 90 (hsp90) 2 days after pupariation (1 day before the pupa reaches the phanerocephalic stage characteristic of diapause). In contrast, hsp23 and hsp70

  4. Abstract The spatial characteristics and temporal variability of the West North Pacific (WNP) typhoon tracks are studied by analyzing the spatial pattern and

    E-print Network

    Liu, Paul

    ) typhoon tracks are studied by analyzing the spatial pattern and temporal variability of the empirical orthogonal functions (EOFs) of the WNP typhoon track density function (TTDF) from 1945 to 2004. The results show that WNP typhoon tracks exhibit three principal EOF Modes. The first EOF Mode represents

  5. Spatial and temporal patterns of exhumation in the Greater Caucasus from low-temperature thermochronometry (Invited)

    NASA Astrophysics Data System (ADS)

    Avdeev, B.; Niemi, N. A.

    2009-12-01

    Results of a low-temperature thermochronometric study are presented that provide new constraints on the spatial and temporal patters of exhumation in the central and eastern Greater Caucasus. This study employed a range of thermochronomtric systems with thermal sensitivity below ~250°C, including ZFT, 40Ar/39Ar, AFT, and apatite and zircon (U-Th)/He. Granitic samples from the central Greater Caucasus in Russia were collected primarily along two N-S transects between Mt. Elbrus and Mt. Kazbek, at ~43.25°E and 43.75°E. ZFT and 40Ar/39Ar results from these samples are Late Paleozoic in age, consistent with regional igneous cooling ages perhaps related to the Variscan orogeny. AFT and (U-Th)/He results indicate slow (<4°C/Myr) cooling from at least 30 until ~5Ma, at which time the rate of cooling sharply increased to ~ 25°C/Myr. These data constrain total exhumation of the central Greater Caucasus to ~10 km, with at least half of this total having been exhumed since the end of the Miocene. The initiation of the first phase of slow exhumation in the central Greater Caucasus is poorly constrained by our rapidly exhumed sample suite, but one slowly cooled sample from the northern edge of the range suggests exhumation may have begun in the Oligocene. No evidence is preserved in the thermochronometric data for an Eocene exhumational event related to the proposed onset of continental-continental collision at this time, but pre-Oligocene exhumation can be constrained by our data to be less than 1-2 km, assuming simple, monotonic cooling. Low-temperature thermochronometry of volcaniclastic rocks from the eastern Caucasus in Azerbaijan (~48.25°E) yield a markedly different story. Cretaceous AFT ages are consistent with stratigraphic estimates of the eruptive age of the volcaniclastic sequence, while (U-Th)/He ages are reset, limiting burial and re-exhumation since the Mesozoic to ~3 km. Rapid exhumation of these rocks began ~3 Ma, and well-preserved post-Mesozoic thermal histories yield no evidence for Paleogene or early Neogene exhumation. These results, together with previously published data, suggest a two-stage exhumational evolution of the Greater Caucasus. In the western and central Greater Caucasus, slow exhumation, and presumably uplift, of the range began likely no earlier than Oligocene time. In Late Miocene or early Pliocene time, coincident with a proposed reorganization of the Eurasia-Arabia plate boundary, the rate of exhumation of the central Greater Caucasus increased five-fold, and exhumation in the eastern Greater Caucasus commenced.

  6. Optimal Control of Saccades by Spatial-Temporal Activity Patterns in the Monkey Superior Colliculus

    PubMed Central

    Goossens, H. H. L. M.; van Opstal, A. J.

    2012-01-01

    A major challenge in computational neurobiology is to understand how populations of noisy, broadly-tuned neurons produce accurate goal-directed actions such as saccades. Saccades are high-velocity eye movements that have stereotyped, nonlinear kinematics; their duration increases with amplitude, while peak eye-velocity saturates for large saccades. Recent theories suggest that these characteristics reflect a deliberate strategy that optimizes a speed-accuracy tradeoff in the presence of signal-dependent noise in the neural control signals. Here we argue that the midbrain superior colliculus (SC), a key sensorimotor interface that contains a topographically-organized map of saccade vectors, is in an ideal position to implement such an optimization principle. Most models attribute the nonlinear saccade kinematics to saturation in the brainstem pulse generator downstream from the SC. However, there is little data to support this assumption. We now present new neurophysiological evidence for an alternative scheme, which proposes that these properties reside in the spatial-temporal dynamics of SC activity. As predicted by this scheme, we found a remarkably systematic organization in the burst properties of saccade-related neurons along the rostral-to-caudal (i.e., amplitude-coding) dimension of the SC motor map: peak firing-rates systematically decrease for cells encoding larger saccades, while burst durations and skewness increase, suggesting that this spatial gradient underlies the increase in duration and skewness of the eye velocity profiles with amplitude. We also show that all neurons in the recruited population synchronize their burst profiles, indicating that the burst-timing of each cell is determined by the planned saccade vector in which it participates, rather than by its anatomical location. Together with the observation that saccade-related SC cells indeed show signal-dependent noise, this precisely tuned organization of SC burst activity strongly supports the notion of an optimal motor-control principle embedded in the SC motor map as it fully accounts for the straight trajectories and kinematic nonlinearity of saccades. PMID:22615548

  7. Zooplankton community structure in a highly turbid environment (Charente estuary, France): Spatio-temporal patterns and environmental control

    NASA Astrophysics Data System (ADS)

    Modéran, Julien; Bouvais, Pierre; David, Valérie; Le Noc, Sandrine; Simon-Bouhet, Benoit; Niquil, Nathalie; Miramand, Pierre; Fichet, Denis

    2010-06-01

    Zooplankton assemblages were studied from January 2007 to January 2008 along the salinity gradient of the Charente estuary (France). A Lagrangian survey was performed monthly at five sampling stations defined by salinity (freshwater, 0.5, 5, 15 and 25) in order to collect zooplankton and measure the main environmental parameters (concentrations of suspended particulate matter, particulate organic carbon, chlorophyll a and phaeopigments). A combination of multivariate cluster analysis, species indicator index and canonical correspondence analysis was used to relate the spatio-temporal patterns of the zooplankton assemblages with environmental drivers. The estuary was divided into three different zones by means of environmental parameters while four zooplankton assemblages were identified along the salinity gradient. The Charente estuary appeared as one of the most turbid systems in Europe, with suspended particulate matter (SPM) concentration reaching 3.5 g l -1 in the Maximum Turbidity Zone (MTZ). Algal heterotrophy and microphytobenthos resuspension from the wide mudflats could be responsible for the relatively high chlorophyll a concentrations measured within this MTZ. Salinity and SPM affected significantly the spatial distribution of zooplankton species while temperature and river flow seemed to control their temporal variations. From a zooplanktonic viewpoint, the highly turbid Charente estuary seemed to match an "ecotone-ecocline" model: the succession of species assemblages along the salinity gradient matched the concept of ecocline while the MTZ, which is a stressful narrow area, could be considered as an ecotone. Although such ecoclinal characteristics seemed to be a general feature of estuarine biocenoses, the ecotone could be more system-specific and biological compartment-specific.

  8. The spatial and temporal patterning of the deep crust and implications for the process of melt extraction.

    PubMed

    Brown, Michael

    2010-01-13

    Volumetrically significant melt production requires crustal temperatures above approximately 800 °C. At the grain scale, the former presence of melt may be inferred based on various microstructures, particularly pseudomorphs of melt pores and grain-boundary melt films. In residual migmatites and granulites, evidence of melt-extraction pathways at outcrop scale is recorded by crystallized products of melt (leucosome) and residual material from which melt has drained (melanosome). These features form networks or arrays that potentially demonstrate the temporal and spatial relations between deformation and melting. As melt volume increases at sites of initial melting, the feedback between deformation and melting creates a dynamic rheological environment owing to localization and strain-rate weakening. With increasing temperature, melt volume increases to the melt connectivity transition, in the range of 2-7 vol% melt, at which point melt may escape in the first of several melt-loss events, where each event represents a batch of melt that left the source and ascended higher in the crust. Each contributing process has characteristic length and time scales, and it is the nonlinear interactions and feedback relations among them that give rise to the dissipative structures and episodicity of melt-extraction events that are recorded as variations in the spatial and temporal patterning of the crust. Focused melt flow occurs by dilatant shear failure of low-melt fraction rocks creating melt-flow networks that allow accumulation and storage of melt, and form the link for melt flow from grain boundaries to veins allowing drainage to crustal-scale ascent conduits. Preliminary indications suggest that anatectic systems are strongly self-organized from the bottom up, becoming more ordered by decreasing the number and increasing the width of ascent conduits from the anatectic zone through the overlying subsolidus crust to the ductile-to-brittle transition zone, where the melt accumulates in plutons. PMID:19948543

  9. Long-Term Citizen-Collected Data Reveal Geographical Patterns and Temporal Trends in Lake Water Clarity

    PubMed Central

    Lottig, Noah R.; Wagner, Tyler; Norton Henry, Emily; Spence Cheruvelil, Kendra; Webster, Katherine E.; Downing, John A.; Stow, Craig A.

    2014-01-01

    We compiled a lake-water clarity database using publically available, citizen volunteer observations made between 1938 and 2012 across eight states in the Upper Midwest, USA. Our objectives were to determine (1) whether temporal trends in lake-water clarity existed across this large geographic area and (2) whether trends were related to the lake-specific characteristics of latitude, lake size, or time period the lake was monitored. Our database consisted of >140,000 individual Secchi observations from 3,251 lakes that we summarized per lake-year, resulting in 21,020 summer averages. Using Bayesian hierarchical modeling, we found approximately a 1% per year increase in water clarity (quantified as Secchi depth) for the entire population of lakes. On an individual lake basis, 7% of lakes showed increased water clarity and 4% showed decreased clarity. Trend direction and strength were related to latitude and median sample date. Lakes in the southern part of our study-region had lower average annual summer water clarity, more negative long-term trends, and greater inter-annual variability in water clarity compared to northern lakes. Increasing trends were strongest for lakes with median sample dates earlier in the period of record (1938–2012). Our ability to identify specific mechanisms for these trends is currently hampered by the lack of a large, multi-thematic database of variables that drive water clarity (e.g., climate, land use/cover). Our results demonstrate, however, that citizen science can provide the critical monitoring data needed to address environmental questions at large spatial and long temporal scales. Collaborations among citizens, research scientists, and government agencies may be important for developing the data sources and analytical tools necessary to move toward an understanding of the factors influencing macro-scale patterns such as those shown here for lake water clarity. PMID:24788722

  10. Spatio-temporal patterns of mass fluxes of micropollutants in Swiss rivers of catchments with different land use

    NASA Astrophysics Data System (ADS)

    Stamm, Christian; van der Voet, Jürgen; Singer, Heinz

    2010-05-01

    It is known from many studies that a large number of micropollutants like pesticides, household products or pharmaceuticals can be found in water bodies. However, there is a general lack of systematic monitoring data that allow for distinguishing between possible sources, detecting temporal trends, or evaluating effects of possible mitigation measures. Including micropollutants in existing monitoring programs is not a trivial task for several reasons (e.g., sorption to sampling equipment, hydrolysis, detection limits etc.). Here, we present systematic concentration and load data for 12 substances (7 pesticides and/or biocides, 3 pharmaceuticals, and 2 anti-corrosives) obtained from a one-year sampling campaign within the "National Long-term Surveillance of Swiss Rivers" (NADUF) programme. Six (partially) nested sampling stations were selected to monitor these compounds in weekly or bi-weekly, flow-proportional samples over one year. Due to the high sensitivity of the LC-MSMS method all compounds could be quantified in almost all samples. Only at the reference site without any effluent from waste water treatment plants and hardly any arable farming, the concentrations were always below the limits of detection of a few ng/L. At all other sites, concentrations generally ranged between 10 and 200 ng/L. Only, the anticorrosive agent benzotriazole often exceeded 1000 ng/L. According to the use of the compounds, different temporal load patterns can be expected. In general, the data confirmed these patterns with almost constant loads of pharmaceuticals at most sites, increased herbicides loads during the periods of agricultural use and positive correlations with discharge year round for biocides used in material protection. However, at some sites the expectations were not met for all compounds. The pain-killer diclofenac for example showed strongly declining loads during the summer months at sites influenced by lake water. This compound is not stable in the epilimnion of lakes, where it has a residence time of several weeks, while it flows through the river system within a few days. This example illustrates how compound properties, season and spatial location may interact and control the occurrence of micropollutants in a stream. The spatial nesting of study catchments made it possible to check the data for plausibility and consistency: we present data on cumulative mass balances downstream and test whether the load development along the river network corresponds to the spatial distribution of possible compound sources (e.g., acreage of arable fields, number of inhabitants etc.). Overall, the data show that monitoring of micropollutants may be achieved even without changing an existing monitoring programme. However, given the generally low concentrations in the composite samples of the NADUF programme compounds with lower use and/or lower stability may fall below the limit of reliable quantification or even detection. A proper interpretation of the data relies on additional (spatio-temporal) information like land use data or precipitation patterns.

  11. Temporal relation of ovulation to salivary and vaginal electrical resistance patterns: implications for natural family planning.

    PubMed

    Moreno, J E; Weitzman, G A; Doody, M C; Gibbons, W E; Besch, P; Goldzieher, J W

    1988-10-01

    An independent assessment of the CUE Monitor (Zetek, Aurora, Colorado) as an ovulation predictor was made with emphasis on its potential role in "natural family planning". The device provides a digital measurement of the electrical resistance of saliva and vaginal secretions. Twenty-nine menstrual cycles from 11 regularly cycling women were monitored with basal temperatures, urinary LH, pelvic ultrasound and the CUE monitor. Patterns of peak salivary electrical resistance were able to predict ovulation on average 5.3 (+/- 1.9 SD) days in advance. Despite variations in total length of the follicular phase from cycle to cycle, the within-subject variation of this predictive interval was quite small. Nadirs in the electrical resistance of vaginal secretions occurred within 2 days of ovulation in all but one patient. Variation in this interval from cycle-to-cycle was small as well. We propose an algorithm for the use of these intervals in "natural family planning" that could safely reduce the monthly abstinence period of present methods. The simplicity, objectivity and consistency of this device could result in their greater general acceptance. PMID:3208515

  12. Spatial and temporal patterns of paleoglaciation across eastern Tibet and Central Asia

    NASA Astrophysics Data System (ADS)

    Stroeven, Arjen P.

    2015-04-01

    Cosmogenic nuclide dating has emerged as a key tool in reconstructing the timing and impacts of past glaciation. Dates from glacial deposits such as moraines and erratics typically provide constraints on the minimum ages of glacial stages. As an international team, we are reconstructing glacial histories of several areas in Central Asia, including parts of the eastern Tibetan Plateau and along the Tian Shan, Altai and Kunlun Mountains. Results to date show significant variations in the timing and extent of glaciation, including areas in the southeast Tibetan Plateau and Tian Shan with extensive valley and small polythermal ice cap glaciation during the global last glacial maximum, in contrast to areas in central and northeast Tibetan Plateau that had very limited valley glacier expansion during the global last glacial maximum. Polythermal ice cap glaciation is inferred for the Haizi Shan area in the southeast Tibetan Plateau on the basis of patterns of glacial and relict landforms, as well as only partial resetting of ages on some erosional features. Numerical modelling attempting to simulate mapped and dated paleoglacial extents predicts limited cooling to attain former maximum glacier extents.

  13. Efficient spatio-temporal local binary patterns for spontaneous facial micro-expression recognition.

    PubMed

    Wang, Yandan; See, John; Phan, Raphael C-W; Oh, Yee-Hui

    2015-01-01

    Micro-expression recognition is still in the preliminary stage, owing much to the numerous difficulties faced in the development of datasets. Since micro-expression is an important affective clue for clinical diagnosis and deceit analysis, much effort has gone into the creation of these datasets for research purposes. There are currently two publicly available spontaneous micro-expression datasets-SMIC and CASME II, both with baseline results released using the widely used dynamic texture descriptor LBP-TOP for feature extraction. Although LBP-TOP is popular and widely used, it is still not compact enough. In this paper, we draw further inspiration from the concept of LBP-TOP that considers three orthogonal planes by proposing two efficient approaches for feature extraction. The compact robust form described by the proposed LBP-Six Intersection Points (SIP) and a super-compact LBP-Three Mean Orthogonal Planes (MOP) not only preserves the essential patterns, but also reduces the redundancy that affects the discriminality of the encoded features. Through a comprehensive set of experiments, we demonstrate the strengths of our approaches in terms of recognition accuracy and efficiency. PMID:25993498

  14. Spatio-temporal patterns of microbial communities in a hydrologically dynamic pristine aquifer.

    PubMed

    Zhou, Yuxiang; Kellermann, Claudia; Griebler, Christian

    2012-07-01

    Seasonal patterns of groundwater and sediment microbial communities were explored in a hydrologically dynamic alpine oligotrophic porous aquifer, characterized by pronounced groundwater table fluctuations. Rising of the groundwater level in consequence of snow melting water recharge was accompanied by a dramatic drop of bacterial Shannon diversity in groundwater from H' = 3.22 ± 0.28 in autumn and winter to H' = 1.31 ± 0.35 in spring and summer, evaluated based on T-RFLP community fingerprinting. Elevated numbers of bacteria in groundwater in autumn followed nutrient inputs via recharge from summer rains and correlated well with highest concentrations of assimilable organic carbon. Sterile sediments incubated to groundwater in monitoring wells were readily colonized reaching maximum cell densities within 2 months, followed by a consecutive but delayed increase and leveling-off of bacterial diversity. After 1 year of incubation, the initially sterile sediments exhibited a similar number of bacteria and Shannon diversity when compared to vital sediment from a nearby river incubated in parallel. The river bed sediment microbial communities hardly changed in composition, diversity, and cell numbers during 1 year of exposure to groundwater. Summing up, the seasonal hydrological dynamics were found to induce considerable dynamics of microbial communities suspended in groundwater, while sediment communities seem unaffected and stable in terms of biomass and diversity. PMID:22452537

  15. Inducible defenses stay up late: temporal patterns of immune gene expression in Tenebrio molitor.

    PubMed

    Johnston, Paul R; Makarova, Olga; Rolff, Jens

    2014-06-01

    The course of microbial infection in insects is shaped by a two-stage process of immune defense. Constitutive defenses, such as engulfment and melanization, act immediately and are followed by inducible defenses, archetypically the production of antimicrobial peptides, which eliminate or suppress the remaining microbes. By applying RNAseq across a 7-day time course, we sought to characterize the long-lasting immune response to bacterial challenge in the mealworm beetle Tenebrio molitor, a model for the biochemistry of insect immunity and persistent bacterial infection. By annotating a hybrid de novo assembly of RNAseq data, we were able to identify putative orthologs for the majority of components of the conserved insect immune system. Compared with Tribolium castaneum, the most closely related species with a reference genome sequence and a manually curated immune system annotation, the T. molitor immune gene count was lower, with lineage-specific expansions of genes encoding serine proteases and their countervailing inhibitors accounting for the majority of the deficit. Quantitative mapping of RNAseq reads to the reference assembly showed that expression of genes with predicted functions in cellular immunity, wound healing, melanization, and the production of reactive oxygen species was transiently induced immediately after immune challenge. In contrast, expression of genes encoding antimicrobial peptides or components of the Toll signaling pathway and iron sequestration response remained elevated for at least 7 days. Numerous genes involved in metabolism and nutrient storage were repressed, indicating a possible cost of immune induction. Strikingly, the expression of almost all antibacterial peptides followed the same pattern of long-lasting induction, regardless of their spectra of activity, signaling possible interactive roles in vivo. PMID:24318927

  16. Inducible Defenses Stay Up Late: Temporal Patterns of Immune Gene Expression in Tenebrio molitor

    PubMed Central

    Johnston, Paul R; Makarova, Olga; Rolff, Jens

    2014-01-01

    The course of microbial infection in insects is shaped by a two-stage process of immune defense. Constitutive defenses, such as engulfment and melanization, act immediately and are followed by inducible defenses, archetypically the production of antimicrobial peptides, which eliminate or suppress the remaining microbes. By applying RNAseq across a 7-day time course, we sought to characterize the long-lasting immune response to bacterial challenge in the mealworm beetle Tenebrio molitor, a model for the biochemistry of insect immunity and persistent bacterial infection. By annotating a hybrid de novo assembly of RNAseq data, we were able to identify putative orthologs for the majority of components of the conserved insect immune system. Compared with Tribolium castaneum, the most closely related species with a reference genome sequence and a manually curated immune system annotation, the T. molitor immune gene count was lower, with lineage-specific expansions of genes encoding serine proteases and their countervailing inhibitors accounting for the majority of the deficit. Quantitative mapping of RNAseq reads to the reference assembly showed that expression of genes with predicted functions in cellular immunity, wound healing, melanization, and the production of reactive oxygen species was transiently induced immediately after immune challenge. In contrast, expression of genes encoding antimicrobial peptides or components of the Toll signaling pathway and iron sequestration response remained elevated for at least 7 days. Numerous genes involved in metabolism and nutrient storage were repressed, indicating a possible cost of immune induction. Strikingly, the expression of almost all antibacterial peptides followed the same pattern of long-lasting induction, regardless of their spectra of activity, signaling possible interactive roles in vivo. PMID:24318927

  17. Spatio-temporal patterns of distribution of West Nile virus vectors in eastern Piedmont Region, Italy

    PubMed Central

    2011-01-01

    Background West Nile Virus (WNV) transmission in Italy was first reported in 1998 as an equine outbreak near the swamps of Padule di Fucecchio, Tuscany. No other cases were identified during the following decade until 2008, when horse and human outbreaks were reported in Emilia Romagna, North Italy. Since then, WNV outbreaks have occurred annually, spreading from their initial northern foci throughout the country. Following the outbreak in 1998 the Italian public health authority defined a surveillance plan to detect WNV circulation in birds, horses and mosquitoes. By applying spatial statistical analysis (spatial point pattern analysis) and models (Bayesian GLMM models) to a longitudinal dataset on the abundance of the three putative WNV vectors [Ochlerotatus caspius (Pallas 1771), Culex pipiens (Linnaeus 1758) and Culex modestus (Ficalbi 1890)] in eastern Piedmont, we quantified their abundance and distribution in space and time and generated prediction maps outlining the areas with the highest vector productivity and potential for WNV introduction and amplification. Results The highest abundance and significant spatial clusters of Oc. caspius and Cx. modestus were in proximity to rice fields, and for Cx. pipiens, in proximity to highly populated urban areas. The GLMM model showed the importance of weather conditions and environmental factors in predicting mosquito abundance. Distance from the preferential breeding sites and elevation were negatively associated with the number of collected mosquitoes. The Normalized Difference Vegetation Index (NDVI) was positively correlated with mosquito abundance in rice fields (Oc. caspius and Cx. modestus). Based on the best models, we developed prediction maps for the year 2010 outlining the areas where high abundance of vectors could favour the introduction and amplification of WNV. Conclusions Our findings provide useful information for surveillance activities aiming to identify locations where the potential for WNV introduction and local transmission are highest. Such information can be used by vector control offices to stratify control interventions in areas prone to the invasion of WNV and other mosquito-transmitted pathogens. PMID:22152822

  18. Temporal Patterns of Inputs to Cerebellum Necessary and Sufficient for Trace Eyelid Conditioning

    PubMed Central

    Kalmbach, Brian E.; Ohyama, Tatsuya

    2010-01-01

    Trace eyelid conditioning is a form of associative learning that requires several forebrain structures and cerebellum. Previous work suggests that at least two conditioned stimulus (CS)-driven signals are available to the cerebellum via mossy fiber inputs during trace conditioning: one driven by and terminating with the tone and a second driven by medial prefrontal cortex (mPFC) that persists through the stimulus-free trace interval to overlap in time with the unconditioned stimulus (US). We used electric stimulation of mossy fibers to determine whether this pattern of dual inputs is necessary and sufficient for cerebellar learning to express normal trace eyelid responses. We find that presenting the cerebellum with one input that mimics persistent activity observed in mPFC and the lateral pontine nuclei during trace eyelid conditioning and another that mimics tone-elicited mossy fiber activity is sufficient to produce responses whose properties quantitatively match trace eyelid responses using a tone. Probe trials with each input delivered separately provide evidence that the cerebellum learns to respond to the mPFC-like input (that overlaps with the US) and learns to suppress responding to the tone-like input (that does not). This contributes to precisely timed responses and the well-documented influence of tone offset on the timing of trace responses. Computer simulations suggest that the underlying cerebellar mechanisms involve activation of different subsets of granule cells during the tone and during the stimulus-free trace interval. These results indicate that tone-driven and mPFC-like inputs are necessary and sufficient for the cerebellum to learn well-timed trace conditioned responses. PMID:20484534

  19. Bioaccumulation patterns and temporal trends of mercury exposure in Wisconsin common loons.

    PubMed

    Fevold, Brick M; Meyer, Michael W; Rasmussen, Paul W; Temple, Stanley A

    2003-01-01

    A long term field study was initiated by the Wisconsin Department of Natural Resources in 1992 to elucidate patterns of common loon (Gavia immer) mercury (Hg) exposure. Analysis of loon blood and feather samples collected from recaptured adult loons in Wisconsin 1992-2000 found evidence of a decline in overall body burdens of mercury in common loons for this region. The interval between sampling individual loons spanned 2-8 years, a sufficient length of time to observe a change in tissue Hg concentrations. Loon chick blood Hg levels declined by 4.9% annually for chicks sampled on 33 lakes during the period 1992-2000. This is the first evidence we are aware of showing a recent regional annual decrease in common loon Hg exposure. Repeated captures of wild loon chicks in Wisconsin shows that blood Hg concentrations can increase during the period of rapid feather growth (weeks 2-5), although the rate of increase is very slow. Mean egg Hg levels ranged from 0.19 to 0.87 microg Hg/g wet weight (ww) in samples collected 1996-2000. Egg Hg concentration was inversely and significantly related to lake pH (p < 0.0001; r2 = 0.55). Adults and chicks were often captured simultaneous during the period 1992-2000. Correlations were highest between sibling blood Hg levels (r = 0.88) and chick blood and adult blood (male r = 0.61, female r = 0.52) Hg levels, likely reflecting the influence of the Hg content of prey from the natal lake on loon blood Hg levels. The relationship between feathers and blood of adults and that of chick blood and adult feathers was weaker. PMID:12739859

  20. Center for Auditory and Acoustic Research

    E-print Network

    Simon, Jonathan Z.

    Center for Auditory and Acoustic Research Institute for Systems Research University of Maryland at . #12;Center for Auditory and Acoustic Research Institute, we derive Spectro-Temporal Receptive Fields (STRFs), a linear, quantitative descriptor of how a cell

  1. Identification of Temporal and Region-Specific Myocardial Gene Expression Patterns in Response to Infarction in Swine

    PubMed Central

    Nonell, Lara; Puigdecanet, Eulàlia; Astier, Laura; Solé, Francesc; Bayes-Genis, Antoni

    2013-01-01

    Molecular mechanisms associated with pathophysiological changes in ventricular remodelling due to myocardial infarction (MI) remain poorly understood. We analyzed changes in gene expression by microarray technology in porcine myocardial tissue at 1, 4, and 6 weeks post-MI. MI was induced by coronary artery ligation in 9 female pigs (30–40 kg). Animals were randomly sacrificed at 1, 4, or 6 weeks post-MI (n?=?3 per group) and 3 healthy animals were also included as control group. Total RNA from myocardial samples was hybridized to GeneChip® Porcine Genome Arrays. Functional analysis was obtained with the Ingenuity Pathway Analysis (IPA) online tool. Validation of microarray data was performed by quantitative real-time PCR (qRT-PCR). More than 8,000 different probe sets showed altered expression in the remodelling myocardium at 1, 4, or 6 weeks post-MI. Ninety-seven percent of altered transcripts were detected in the infarct core and 255 probe sets were differentially expressed in the remote myocardium. Functional analysis revealed 28 genes de-regulated in the remote myocardial region in at least one of the three temporal analyzed stages, including genes associated with heart failure (HF), systemic sclerosis and coronary artery disease. In the infarct core tissue, eight major time-dependent gene expression patterns were recognized among 4,221 probe sets commonly altered over time. Altered gene expression of ACVR2B, BID, BMP2, BMPR1A, LMNA, NFKBIA, SMAD1, TGFB3, TNFRSF1A, and TP53 were further validated. The clustering of similar expression patterns for gene products with related function revealed molecular footprints, some of them described for the first time, which elucidate changes in biological processes at different stages after MI. PMID:23372767

  2. Spatial and temporal patterns in the hyperbenthic community structure in a warm temperate southern African permanently open estuary

    NASA Astrophysics Data System (ADS)

    Heyns, Elodie; Froneman, William

    2010-06-01

    The spatial and temporal patterns in the hyperbenthic community structure (>500 ?m) in the warm temperate, permanently open Kariega Estuary situated along the south-eastern coastline of South Africa was investigated monthly over a period of twelve months. Data were collected using a modified hyperbenthic sledge at six stations along the length of the estuary. Physico-chemical data indicate the presence of a constant reverse salinity gradient, with highest salinities measured in the upper reaches and lowest at the mouth of the estuary. Strong seasonal patterns in temperature, dissolved oxygen and total chlorophyll- a (chl- a) concentration were evident. Total average hyperbenthic densities ranged between 0.4 and 166 ind.m -3 in the lower net and between 0.2 and 225 ind.m -3 in the upper net. Hyperbenthic biomass values ranged between 0.02 and 11.9 mg.dry weight.m -3 in the lower net and between 0.02 and 17.4 mg.dry weight.m -3 in the upper net. Both the lower and upper nets were numerically dominated by decapods (mainly brachyuran crab zoea) with the exception of June and July 2008 when mysids (mainly Mesopodopsis wooldridgei) dominated, comprising up to 72.4 ± 58.14% of the total abundance in the lower net. A redundancy analysis (RDA) indicated that 99.2% of the variance in the hyperbenthic community structure could be explained by the first two canonical axes. Axis one, which accounted for 96.8% of the total variation detected in the ordination plot was highly correlated with sedimentary organic content and to a lesser extent the chl- a concentration within the Kariega Estuary. The correlations with the second canonical axis (2.4%) were less obvious, however, salinity and seston concentration were weakly correlated with this axis.

  3. Classifying acoustic signals into phoneme categories: average and dyslexic readers make use of complex dynamical patterns and multifractal scaling properties of the speech signal.

    PubMed

    Hasselman, Fred

    2015-01-01

    Several competing aetiologies of developmental dyslexia suggest that the problems with acquiring literacy skills are causally entailed by low-level auditory and/or speech perception processes. The purpose of this study is to evaluate the diverging claims about the specific deficient peceptual processes under conditions of strong inference. Theoretically relevant acoustic features were extracted from a set of artificial speech stimuli that lie on a /bAk/-/dAk/ continuum. The features were tested on their ability to enable a simple classifier (Quadratic Discriminant Analysis) to reproduce the observed classification performance of average and dyslexic readers in a speech perception experiment. The 'classical' features examined were based on component process accounts of developmental dyslexia such as the supposed deficit in Envelope Rise Time detection and the deficit in the detection of rapid changes in the distribution of energy in the frequency spectrum (formant transitions). Studies examining these temporal processing deficit hypotheses do not employ measures that quantify the temporal dynamics of stimuli. It is shown that measures based on quantification of the dynamics of complex, interaction-dominant systems (Recurrence Quantification Analysis and the multifractal spectrum) enable QDA to classify the stimuli almost identically as observed in dyslexic and average reading participants. It seems unlikely that participants used any of the features that are traditionally associated with accounts of (impaired) speech perception. The nature of the variables quantifying the temporal dynamics of the speech stimuli imply that the classification of speech stimuli cannot be regarded as a linear aggregate of component processes that each parse the acoustic signal independent of one another, as is assumed by the 'classical' aetiologies of developmental dyslexia. It is suggested that the results imply that the differences in speech perception performance between average and dyslexic readers represent a scaled continuum rather than being caused by a specific deficient component. PMID:25834769

  4. Granger causality analysis reveals distinct spatio-temporal connectivity patterns in motor and perceptual visuo-spatial working memory

    PubMed Central

    Protopapa, Foteini; Siettos, Constantinos I.; Evdokimidis, Ioannis; Smyrnis, Nikolaos

    2014-01-01

    We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no) change detection task with memory and non-memory conditions. On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes. Movement-memory trial types exhibited higher degree nodes during the first 2 s of the delay period, mainly at central, left frontal and right-parietal areas. Change detection-memory trial types resulted in a three-peak temporal pattern of the total degree with higher degree nodes emerging mainly at central, right frontal, and occipital areas. Functional connectivity networks resulting from non-memory trial types were characterized by more sparse structures for both tasks. The movement-memory trial types encompassed an apparent coarse flow from frontal to parietal areas while the opposite flow from occipital, parietal to central and frontal areas was evident for the change detection-memory trial types. The differences among tasks and conditions were more profound in ? (8–12 Hz) and ? (12–30 Hz) and less in ? (30–45 Hz) band. Our results favor the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations. PMID:25431557

  5. Patterns of Spatial and Temporal Distribution of Humpback Whales at the Southern Limit of the Southeast Pacific Breeding Area

    PubMed Central

    Guidino, Chiara; Llapapasca, Miguel A.; Silva, Sebastian; Alcorta, Belen; Pacheco, Aldo S.

    2014-01-01

    Understanding the patterns of spatial and temporal distribution in threshold habitats of highly migratory and endangered species is important for understanding their habitat requirements and recovery trends. Herein, we present new data about the distribution of humpback whales (Megaptera novaeangliae) in neritic waters off the northern coast of Peru: an area that constitutes a transitional path from cold, upwelling waters to warm equatorial waters where the breeding habitat is located. Data was collected during four consecutive austral winter/spring seasons from 2010 to 2013, using whale-watching boats as platforms for research. A total of 1048 whales distributed between 487 groups were sighted. The spatial distribution of humpbacks resembled the characteristic segregation of whale groups according to their size/age class and social context in breeding habitats; mother and calf pairs were present in very shallow waters close to the coast, while dyads, trios or more whales were widely distributed from shallow to moderate depths over the continental shelf break. Sea surface temperatures (range: 18.2–25.9°C) in coastal waters were slightly colder than those closer to the oceanic realm, likely due to the influence of cold upwelled waters from the Humboldt Current system. Our results provide new evidence of the southward extension of the breeding region of humpback whales in the Southeast Pacific. Integrating this information with the knowledge from the rest of the breeding region and foraging grounds would enhance our current understanding of population dynamics and recovery trends of this species. PMID:25391137

  6. Modelling Spatial and Temporal Forest Cover Change Patterns (1973-2020): A Case Study from South Western Ghats (India)

    PubMed Central

    Giriraj, Amarnath; Irfan-Ullah, Mohammed; Murthy, Manchi Sri Ramachandra; Beierkuhnlein, Carl

    2008-01-01

    This study used time series remote sensing data from 1973, 1990 and 2004 to assess spatial forest cover change patterns in the Kalakad-Mundanthurai Tiger Reserve (KMTR), South Western Ghats (India). Analysis of forest cover changes and its causes are the most challenging areas of landscape ecology, especially due to the absence of temporal ground data and comparable space platform based data. Comparing remotely sensed data from three different sources with sensors having different spatial and spectral resolution presented a technical challenge. Quantitative change analysis over a long period provided a valuable insight into forest cover dynamics in this area. Time-series maps were combined within a geographical information system (GIS) with biotic and abiotic factors for modelling its future change. The land-cover change has been modelled using GEOMOD and predicted for year 2020 using the current disturbance scenario. Comparison of the forest change maps over the 31-year period shows that evergreen forest being degraded (16%) primarily in the form of selective logging and clear felling to raise plantations of coffee, tea and cardamom. The natural disturbances such as forest fire, wildlife grazing, invasions after clearance and soil erosion induced by anthropogenic pressure over the decades are the reasons of forest cover change in KMTR. The study demonstrates the role of remote sensing and GIS in monitoring of large-coverage of forest area continuously for a given region over time more precisely and in cost-effective manner which will be ideal for conservation planning and prioritization.

  7. Temporal variation in the dispersion patterns of metazoan parasites of a coastal fish species from the Gulf of Mexico.

    PubMed

    Vidal-Martínez, V M; Pal, P; Aguirre-Macedo, M L; May-Tec, A L; Lewis, J W

    2014-03-01

    Global climate change (GCC) is expected to affect key environmental variables such as temperature and rainfall, which in turn influence the infection dynamics of metazoan parasites in tropical aquatic hosts. Thus, our aim was to determine how temporal patterns of temperature and rainfall influence the mean abundance and aggregation of three parasite species of the fish Cichlasoma urophthalmus from Yucatán, México. We calculated mean abundance and the aggregation parameter of the negative binomial distribution k for the larval digeneans Oligogonotylus manteri and Ascocotyle (Phagicola) nana and the ectoparasite Argulus yucatanus monthly from April 2005 to December 2010. Fourier analysis of time series and cross-correlations were used to determine potential associations between mean abundance and k for the three parasite species with water temperature and rainfall. Both O. manteri and A. (Ph.) nana exhibited their highest frequency peaks in mean abundance at 6 and 12 months, respectively, while their peak in k occurred every 24 months. For A. yucatanus the frequency peaks in mean abundance and k occurred every 12 months. We suggest that the level of aggregation at 24 months of O. manteri increases the likelihood of fish mortality. Such a scenario is less likely for A. (Ph.) nana and A. yucatanus, due to their low infection levels. Our findings suggest that under the conditions of GCC it would be reasonable to expect higher levels of parasite aggregation in tropical aquatic hosts, in turn leading to a potential increase in parasite-induced host mortality. PMID:23298602

  8. Robust detection of small infrared objects in maritime scenarios using local minimum patterns and spatio-temporal context

    NASA Astrophysics Data System (ADS)

    Qi, Baojun; Wu, Tao; He, Hangen

    2012-02-01

    Here, we describe a novel approach for small surface object detection with an onboard infrared (IR) camera working in maritime scenes. First, we propose a simple but effective tool called the local minimum patterns (LMP), which are theoretically the approximated coefficients of some stationary wavelet transforms, for single image background estimation. Second, potential objects are segmented by an adaptive threshold estimated from the saliency map, which is obtained by background subtraction. Using the LMP based wavelet transforms and the histogram of the saliency map, the threshold can be automatically determined by singularity analysis. Next, we localize potential objects by our proposed fast clustering algorithm, which, compared with popular K-Means, is much faster and less sensitive to noises. To make the surveillance system more reliable, we finally discuss how to integrate multiple cues, such as scene geometry constraints and spatio-temporal context, into detections by Bayesian inference. The proposed method has shown to be both effective and efficient by our extensive experiments on some challenging data sets with a competitive performance over some state-of-the-art techniques.

  9. Temporal and spatial patterns of Cenozoic and Late Mesozoic erosion and deposition along the western margin of southern Africa

    SciTech Connect

    Brown, R.W.; Gleadow, A.J.W. (Latrobe Univ., Bundoora (Australia)); Rust, D.J.; Summerfield, M.A. (Univ. of Edinburgh (Scotland))

    1990-05-01

    Compared with subsidence history and eustatic sea level change, sediment supply has been a neglected component of studies of passive margin stratigraphy. The spatial and temporal pattern of sediment supply to continental margin, however, is a critical factor in determining the architecture of offshore sedimentary sequences. Sediment routing across passive margins is controlled primarily by their tectonic development and the consequent morphological evolution of the subaerial part of the margin. By combining offshore sediment volume and sedimentation rate data based on isopach maps and borehole records with apatite fission-track analysis and denudational modeling onland, the depositional history of the western margin of southern Africa has been related to its geomorphic response to continental rifting. The sediment volume data indicate a declining rate of sedimentation after rifting in the Early Cretaceous despite a probable enlargement of the sediment source area through time. Similarly, apatite fission-track ages and confined track length distributions indicate an Early Cretaceous episode of relatively high erosion rates which affected areas both inland and oceanward of the major topographic discontinuity along the margin represented by the Great Escarpment. Late Cenozoic rates of erosion and sediment supply have been low, although much of the sediment source area is still at a significant elevation. Although aridity may have contributed to this reduction in sediment supply, the morphological response to the tectonic evolution of the margin has also been crucial.

  10. Complex Patterns of Alternative Splicing Mediate the Spatial and Temporal Distribution of Perlecan/UNC-52 in Caenorhabditis elegans

    PubMed Central

    Mullen, Gregory P.; Rogalski, Teresa M.; Bush, Jason A.; Gorji, Poupak Rahmani; Moerman, Donald G.

    1999-01-01

    The unc-52 gene encodes the nematode homologue of mammalian perlecan, the major heparan sulfate proteoglycan of the extracellular matrix. This is a large complex protein with regions similar to low-density lipoprotein receptors, laminin, and neural cell adhesion molecules (NCAMs). In this study, we extend our earlier work and demonstrate that a number of complex isoforms of this protein are expressed through alternative splicing. We identified three major classes of perlecan isoforms: a short form lacking the NCAM region and the C-terminal agrin-like region; a medium form containing the NCAM region, but still lacking the agrin-like region; and a newly identified long form that contains all five domains present in mammalian perlecan. ?Using region-specific antibodies and unc-52 mutants, we reveal a complex spatial and temporal expression pattern for these UNC-52 isoforms. As well, using a series of mutations affecting different regions and thus different isoforms of UNC-52, we demonstrate that the medium NCAM-containing isoforms are sufficient for myofilament lattice assembly in developing nematode body-wall muscle. Neither short isoforms nor isoforms containing the C-terminal agrin-like region are essential for sarcomere assembly or muscle cell attachment, and their role in development remains unclear. PMID:10512861

  11. Temporal patterns of charcoal burning suicides among the working age population in Hong Kong SAR: the influence of economic activity status and sex

    PubMed Central

    2012-01-01

    Background Charcoal burning in a sealed room has recently emerged as the second most common suicide means in Hong Kong, causing approximately 200 deaths each year. As charcoal burning suicide victims have a unique sociodemographic profile (i.e., predominantly economically active men), they may commit suicide at specific times. However, little is known about the temporal patterns of charcoal burning suicides. Methods Suicide data from 2001 to 2008 on victims of usual working age (20–59) were obtained from the registered death files of the Census and Statistics Department of Hong Kong. A total of 1649 cases of charcoal burning suicide were analyzed using a two-step procedure, which first examined the temporal asymmetries in the incidence of suicide, and second investigated whether these asymmetries were influenced by sex and/or economic activity status. Poisson regression analyses were employed to model the monthly and daily patterns of suicide by economic activity status and sex. Results Our findings revealed pronounced monthly and daily temporal variations in the pattern of charcoal burning suicides in Hong Kong. Consistent with previous findings on overall suicide deaths, there was an overall spring peak in April, and Monday was the common high risk day for all groups. Although sex determined the pattern of variation in charcoal burning suicides, the magnitude of the variation was influenced by the economic activity status of the victims. Conclusion The traditional classification of suicide methods as either violent or nonviolent tends to elide the temporal variations of specific methods. The interaction between sex and economic activity status observed in the present study indicates that sex should be taken into consideration when investigating the influence of economic activity status on temporal variations of suicide. This finding also suggests that suicide prevention efforts should be both time- and subgroup-specific. PMID:22770504

  12. Adaptive Acoustical-Environmental Assessment for the Focused Acoustic Field-05 At-sea Exercise

    E-print Network

    Schmidt, Henrik

    column extremely complex. The properties of the seabed are also variable, which impact acousticAdaptive Acoustical-Environmental Assessment for the Focused Acoustic Field-05 At-sea Exercise Ding environment span a wide range of spatial and temporal scales. From an acoustic viewpoint, the limited

  13. Generating Linear Temporal Logic Formulas for PatternBased Specifications Salamah Salamah, Vladik Kreinovich, and Ann Q. Gates

    E-print Network

    Ward, Karen

    pattern is considered. Based on a selected pattern, SPS provides a specification for each type of scope­ current behavior over pattern and scope parameters. In this work, we present an approach to support the au behavior, defines the pattern's re­ lationship with other patterns, and defines the scope over which

  14. Generating Linear Temporal Logic Formulas for Pattern-Based Speci cations Salamah Salamah, Vladik Kreinovich, and Ann Q. Gates

    E-print Network

    Ward, Karen

    pattern is associ- ated with a scope that de nes the extent of program exe- cution over which a property harder to write speci cations. The Speci cation Pattern System [3] de nes patterns and scopes to assist nes the pattern's re- lationship with other patterns, and de nes the scope over which the property

  15. Generating Linear Temporal Logic Formulas for Pattern-Based Speci cations Salamah Salamah, Vladik Kreinovich, and Ann Q. Gates

    E-print Network

    Kreinovich, Vladik

    pattern is associ- ated with a scope that de nes the extent of program exe- cution over which a property to write speci cations. The Speci cation Pattern System [3] de nes patterns and scopes to assist nes the pattern's re- lationship with other patterns, and de nes the scope over which the property

  16. Temporal expression patterns of insulin-like growth factor binding protein-4 in the embryonic and postnatal rat brain

    PubMed Central

    2013-01-01

    Background IGFBP-4 has been considered as a factor involving in development of the central nervous system (CNS), but its role needs to be further clarified. In present study, the localization of IGFBP-4 expression in the embryonic forebrain, midbrain and hindbrain was determined using immunohistochemistry, and the levels of IGFBP-4 protein and mRNA were semi-quantified using RT-PCR and Western blot in the embryonic (forebrain, midbrain and hindbrain) and postnatal brain (cerebral cortex, cerebellum and midbrain). Results A clear immunoreactivity of IGFBP-4 covered almost the entire embryonic brain (forebrain, midbrain, hindbrain) from E10.5 to E18.5, except for the area near the ventricle from E14.5. The change of IGFBP-4 mRNA level was regularly from E10.5 to E18.5: its expression peaked at E13.5 and E14.5, followed by gradual decreasing from E15.5. The expression of IGFBP-4 protein was similar to that of mRNA in embryonic stage. After birth, the pattern of IGFBP-4 expression was shown to be rather divergent in different brain areas. In the cerebral cortex, the IGFBP-4 mRNA increased gradually after birth (P0), while the protein showed little changes from P0 to P28, but decreased significantly at P70. In the cerebellum, the IGFBP-4 mRNA decreased gradually from P0, reached the lowest level at P21, and then increased again. However, its protein level gradually increased from P0 to P70. In the midbrain, the IGFBP-4 mRNA first decreased and reached its lowest level at P28 before it increased, while the protein remained constant from P0 to P70. At P7, P14, P21, P28 and P70, the levels of IGFBP-4 mRNA in the cerebral cortex were significantly higher than that in the cerebellum or in the midbrain. Differently, the protein levels in the cerebellum were significantly higher than that either in the cerebral cortex or in the midbrain at P14, P21, P28 and P70. Conclusions The temporal expression pattern of IGFBP-4 in the embryonic brain from E10.5 to E18.5 was consistent with the course of neurogenesis in the ventricular zone, suggesting an important role of IGFBP-4 in regulating differentiation of neural stem cells. A strikingly higher abundance of the IGFBP-4 protein observed in the cerebellum from P14 to P70 suggests that IGFBP-4 may participate in the maintenance of cerebellar plasticity. PMID:24175938

  17. Spatial and Temporal Patterns of Observed Bark Beetle-Caused Tree Mortality in Western United States and British Columbia

    NASA Astrophysics Data System (ADS)

    Meddens, A. J.; Hicke, J. A.; Ferguson, C. A.

    2011-12-01

    Outbreaks of aggressive bark beetle species cause widespread tree mortality, affecting wildlife habitat, wildfire risk, forest recovery, biogeochemical cycling, and biophysical processes. As a result, agencies responsible for forest management in the US and British Columbia are concerned about monitoring outbreaks and so conduct aerial surveys to map these forest disturbances. Here, we describe a gridded product of bark beetle disturbances for the western conterminous United States (1997-2009) and British Columbia (2001-2009). We converted aerial survey polygon data into 1-km2 grids for each combination of host type (e.g., lodgepole pine) and bark beetle species (e.g., mountain pine beetle) available in the US, and for each bark beetle species available in British Columbia. Polygon data are considered "affected area" because the polygons include live and killed trees. We converted affected area to mortality area within each grid cell for each year. We compared the number of killed trees from the US data set with high-resolution classified imagery in Idaho, Colorado, and New Mexico, finding that the number of trees reported by the aerial surveys in these locations was substantially underestimated. We adjusted mortality area for the US and found better matches with the spatial patterns and severity of the British Columbia mortality area. As a result, we produced US grids for lower (from the original aerial survey) and upper (with adjustment) estimates. Bark beetle mortality occurred across the entire study domain and temporal and spatial patterns differed among bark beetle species. The calculated mortality area from all bark beetles combined was 0.42 million ha for the lower estimate and 5.04 million ha for the upper estimate in the western conterminous US from 1997 to 2009, and 5.07 million ha in British Columbia from 2001 to 2009. The analyses suggest that mortality area caused by bark beetles in the western conterminous US exceeded the British Columbia mortality area in recent years. We conclude by discussing the uses and limitations of these data in future ecological studies.

  18. Observing and predicting the spatial-temporal pattern of runoff generation processes from the watershed to the regional scale

    NASA Astrophysics Data System (ADS)

    Weiler, M.

    2012-12-01

    Runoff generation processes are the key to understand and predict watershed dynamics and behaviour under current as well as under changing conditions. A variety of approaches have been developed to observe these processes at the plot scale (e.g. infiltration and sprinkling experiments), the hillslope scale (soil moisture and piezometer networks and trenching) and the watershed scale (hydrograph separation with stable isotopes and natural tracers). However, predicting the four major runoff generation mechanisms (infiltration excess, saturation excess, subsurface flow and deep percolation) without detailed observation in ungauged watershed is still a challenge, but a prerequisite to track water flow pathways and to make adequate prediction for hydrological extremes. Methods have been developed to map dominant runoff generation processes in the field and with digital maps, however, these methods are often static and do not consider the temporal dynamics of runoff generation processes frequently observed with the various experimental approaches. The recently developed parsimonious rainfall-runoff model DROGen can bridge the gap between across spatial scales in ungauged watersheds since parameters are not calibrated. The model incorporates high-resolution GIS data (1m resolution DEM, land-use, impervious surfaces), hydro-geological and pedological data as well as information about the effect of macropores and preferential flow pathways on runoff generation processes with a comprehensive knowledge base from various field observations and experiments. The model was applied to over 6500 meso-scale watershed in the State of Baden-Württemberg in Germany and 15 gauged watersheds were selected for detailed model evaluation. The evaluation was done with field-mapping of runoff generation processes for direct comparison with the simulated pattern of runoff processes for different types of precipitation (high intensity and short duration / low intensity and long duration) and benchmarking of several observed floods in these watersheds. The simulated patterns were analysed in more detail to gain a better understanding of the initial conditions (soil moisture) and different precipitation events and to derive scaling relationships. The model DROGen is different from many other model approaches not only with respect to spatial resolution and model calibration, but in particular by incorporating a detailed understanding of hydrological processes, obtained from many experimental studies on runoff generation at the plot and hillslope scale worldwide.

  19. Spatial and Temporal Patterns in Forest Harvest, Fire, and Pest/Pathogen Disturbance for Western and Eastern Oregon

    NASA Astrophysics Data System (ADS)

    Turner, D. P.; Kennedy, R. E.; Ritts, W. D.

    2014-12-01

    The disturbance regime in temperate zone forests is a function of both human interventions - such as thinning and harvesting - and background events, including wildfire and outbreaks of pests and pathogens. Forest management requires a good understanding of the relative magnitude and trends in these disturbances, but the inherent spatial heterogeneity in their distribution and the large size of the relevant domains makes monitoring a challenge. Satellite remote sensing offers various tools to address this challenge, and in this study we employed 25 years of Landsat data (1986-2010) to characterize the disturbance regime over forested areas in the state of Oregon, U.S.A. Segmentation of the temporal trajectory of a spectral vegetation index over the study interval was used to specify the year, duration, and intensity of disturbances for each Landsat pixel. Attribution was to Harvest/Thinning, Fire, and Other (mostly pests and pathogens). The western side of the state had a larger proportion of its area disturbed over the study interval (29% vs. 23% for Eastern Oregon). The incidence of Harvest/Thinning there greatly exceeded the incidence of Fire and Other disturbance. In the more xeric eastern OR, the incidence of Fire was greater than the incidence of Harvest/Thinning or Other. The annual area harvested or thinned increased from the 1990s to the 2000s in western Oregon, but decreased in eastern Oregon. In both cases, the area burned increased. These observed patterns in disturbance will be input to a spatially-distributed biogeochemistry model to evaluate related impacts on the carbon and hydrologic cycles.

  20. Patterns of microRNA expression in normal and early Alzheimer's disease human temporal cortex: white matter versus gray matter

    PubMed Central

    Wang, Wang-Xia; Huang, Qingwei; Hu, Yanling; Stromberg, Arnold J.

    2011-01-01

    MicroRNA (miRNA) expression was assessed in human cerebral cortical gray matter (GM) and white matter (WM) in order to provide the first insights into the difference between GM and WM miRNA repertoires across a range of Alzheimer's disease (AD) pathology. RNA was isolated separately from GM and WM portions of superior and middle temporal cerebral cortex (N = 10 elderly females, postmortem interval < 4 h). miRNA profiling experiments were performed using state-of-the-art Exiqon© LNA-microarrays. A subset of miRNAs that appeared to be strongly expressed according to the microarrays did not appear to be conventional miRNAs according to Northern blot analyses. Some well-characterized miRNAs were substantially enriched in WM as expected. However, most of the miRNA expression variability that correlated with the presence of early AD-related pathology was seen in GM. We confirm that downregulation of a set of miRNAs in GM (including several miR-15/107 genes and miR-29 paralogs) correlated strongly with the density of diffuse amyloid plaques detected in adjacent tissue. A few miRNAs were differentially expressed in WM, including miR-212 that is downregulated in AD and miR-424 which is upregulated in AD. The expression of certain miRNAs correlates with other miRNAs across different cases, and particular subsets of miRNAs are coordinately expressed in relation to AD-related pathology. These data support the hypothesis that patterns of miRNA expression in cortical GM may contribute to AD pathogenetically, because the aggregate change in miRNA expression observed early in the disease would be predicted to cause profound changes in gene expression. PMID:20936480

  1. Spatio-temporal patterns of recent and future climate extremes in the eastern Mediterranean and Middle East region

    NASA Astrophysics Data System (ADS)

    Kostopoulou, E.; Giannakopoulos, C.; Hatzaki, M.; Karali, A.; Hadjinicolaou, P.; Lelieveld, J.; Lange, M. A.

    2014-06-01

    Recent and future changes in temperature and precipitation climate extremes are estimated using the Hadley Centre PRECIS ("Providing REgional Climates for Impacts Studies") climate model for the eastern Mediterranean and Middle East region. The area of interest is considered vulnerable to extreme climate events as there is evidence for a temperature rise while precipitation tends to decline, suggesting likely effects on vital socioeconomic sectors in the region. Observations have been obtained for the recent period (1961-1990) and used to evaluate the model output. The spatial distribution of recent temporal trends in temperature indicates strong increasing in minimum temperature over the eastern Balkan Peninsula, Turkey and the Arabian Peninsula. The rate of warming reaches 0.4-0.5 °C decade-1 in a large part of the domain, while warming is expected to be strongest in summer (0.6-0.7 °C decade-1) in the eastern Balkans and western Turkey. The trends in annual and summer maximum temperature are estimated at approximately 0.5 and 0.6 °C decade-1 respectively. Recent estimates do not indicate statistically significant trends in precipitation except for individual sub-regions. Results indicate a future warming trend for the study area over the last 30 years of the 21st century. Trends are estimated to be positive and statistically significant in nearly the entire region. The annual trend patterns for both minimum and maximum temperature show warming rates of approximately 0.4-0.6 °C decade-1, with pronounced warming over the Middle Eastern countries. Summer temperatures reveal a gradual warming (0.5-0.9 °C decade-1) over much of the region. The model projects drying trends by 5-30% in annual precipitation towards the end of the 21st century, with the number of wet days decreasing at the rate of 10-30 days year-1, while heavy precipitation is likely to decrease in the high-elevation areas by 15 days year-1.

  2. Spatial and temporal patterns of recent and future climate extremes in the Eastern Mediterranean and Middle East region

    NASA Astrophysics Data System (ADS)

    Kostopoulou, E.; Giannakopoulos, C.; Hatzaki, M.; Karali, A.; Hadjinicolaou, P.; Lelieveld, J.; Lange, M. A.

    2013-09-01

    Recent and future changes in temperature and precipitation climate extremes are estimated using the Hadley Centre PRECIS climate model for the Eastern Mediterranean and Middle East region. The area of interest is considered vulnerable to extreme climate events as there is evidence for a temperature rise while precipitation tends to decline, suggesting likely effects on vital socioeconomic sectors in the region. Observations have been obtained for the recent period (1961-1990) and used to evaluate the model output. The spatial distribution of recent temporal trends in temperature indicates strong increasing in minimum temperature over the eastern Balkan Peninsula, Turkey and the Arabian Peninsula. The rate of warming reaches 0.4-0.5 °C decade-1 in a large part of the domain, while warming is expected to be strongest in summer (0.6-0.7 °C decade-1) in the E-Balkans and W-Turkey. The trends in annual and summer maximum temperature are estimated at approximately 0.5 and 0.6 °C decade-1. Recent estimates do not indicate statistically significant trends in precipitation except for individual sub-regions. Results indicate a future warming trend for the study area over the last 30 yr of the 21st century. Trends are estimated to be positive and statistically significant in nearly the entire region. The annual trend patterns for both minimum and maximum temperature show warming rates of approximately 0.4-0.6 °C decade-1, with pronounced warming over the Middle Eastern countries. Summer temperatures reveal a gradual warming (0.5-0.9 °C decade-1) over much of the region. The model projects drying trends by 5-30% in annual precipitation towards the end of the 21st century, with the number of wet days decreasing at the rate of 10-30 days yr-1, while heavy precipitation is likely to decrease in the high-elevation areas by 15 days yr-1.

  3. Spatial and temporal patterns of Amazon rainfall. Consequences for the planning of agricultural occupation and the protection of primary forests.

    PubMed

    Sombroek, W

    2001-11-01

    The spatial and temporal pattern of annual rainfall and the strength of the dry season within the Amazon region are poorly known. Existing rainfall maps are based on the data from full-scale, long-term meteorological stations, operated by national organizations linked to the World Meteorological Organisation, such as INMET in Brazil. Stations with 30 or more years of uninterrupted and reliable recordings are very few, considering the size of the region, and most of them are located along the major rivers. It has been suggested that rainfall conditions away from these rivers are substantially different. An analysis has been made of the records of a network of simple pluviometric sites in the Brazilian part of the region as maintained by the National Agency for Electric Energy (ANEEL) since 1970. The latter data sets were used to draw more detailed maps on annual rainfall, and on the strength of the dry season in particular; average number of consecutive months with less than 100 mm, 50 mm, and 10 mm, respectively. Also, some data were obtained on the spatial expression of El Niño events within the region. Subregional differences are large, and it is argued that they are important for the success or failure of agricultural settlements; for the hazard of large-scale fire damage of the still existing primary forest vegetation; for the functioning of this land cover as stock and sink of CO2, and for the likelihood that secondary forests on abandoned agricultural lands will have less biomass. The effects of past El Niño rainfall anomalies on the biodiversity of the natural savannahs within the forest region are discussed. PMID:11795213

  4. Reconstructing spatial and temporal patterns of soil formation in an anthropogenic drift sand area in Northeastern Germany

    NASA Astrophysics Data System (ADS)

    Schneider, Anna; Hirsch, Florian; Raab, Thomas; Wechler, Klaus-Peter

    2015-04-01

    On the sandy deposits of the Weichselian glaciation, soils developed during periods of landscape stability are often conserved under windblown sand. The relatively diverse morphology of dune areas and the possibilities for dating the accumulation of windblown sediment offer good opportunities to improve the understanding of spatial and temporal patterns of soil formation. However, a mapping of the buried soils and surfaces is often limited to single outcrops. In the forefield of the open-cast mine Cottbus-Nord, archaeological excavations in an about 10 ha dune and drift sand area revealed widespread buried soils, mainly podzols, of different characteristics. Archaeological findings give evidence for the age of the buried surfaces. The densely spaced excavation trenches allow for reconstructing the distribution of fossil and recent soils in a high spatial resolution. We created and analyzed digital models of the recent surface and the buried soils using a combination of methods: To characterize the recent ground surface, we used microdrone-based photogrammetry, LIDAR-based elevation data and GPS. To create a digital model of the palaeosurface and the distribution of fossil soils, we used soil and sedimentological mapping along excavation trenches, mapping of the elevation of excavated palaeosurfaces, and prospection of the fossil soils by Ground Penetrating Radar. Our studies reveal a high vertical and horizontal heterogeneity of soils, with varying thicknesses of eluvial and illuvial horizons and varying degrees of organic compound and sesquioxide accumulation. First results reflect several phases of landscape development: i) the formation of a Late Pleistocene soil on fluvio-eolian deposits, ii) a fossilization by eolian sands which underwent intensive podsolization, and iii) a land use-induced eolian remobilization of the sands. The soil characteristics' spatial distribution in relation to surface morphology indicates a high relevance of lateral leachate transport, even along very low gradients.

  5. Spatial and temporal patterns of movement and migration at spawning aggregations of red hind, Epinephelus guttatus , in the U.S. Virgin Islands

    Microsoft Academic Search

    Richard S. Nemeth; Jeremiah Blondeau; Steve Herzlieb; Elizabeth Kadison

    2007-01-01

    This study compared the spatial and temporal patterns of red hind, Epinephelus guttatus, movement and migration from annual spawning aggregations on St Thomas (STT) and St Croix (STX), United States Virgin Islands.\\u000a Around STT E. guttatus migrated 6–33 km from a functional spawning migration area of 500 km2 and around STX E. guttatus migrated 5–18 km from an area of 90 km2. Similarities between

  6. An observational study of the temporal and spatial patterns of Marek's-disease-associated leukosis condemnation of young chickens in the United States of America.

    PubMed

    Kennedy, David A; Dunn, John R; Dunn, Patricia A; Read, Andrew F

    2015-07-01

    Marek's disease, a disease primarily affecting immature chickens, is a worldwide problem that has on at least three occasions threatened the poultry industry in the United States. A rich dataset to study the epidemiology of this disease is available because the United States Department of Agriculture has required mandatory inspections of all commercially sold poultry of significant scale since the mid-20th century with over 99% of all chickens inspected. This dataset includes monthly totals aggregated by state since 1961 of the number of "young chickens" inspected and the number with "leukosis", a condemnation category that is almost always associated with Marek's disease in this category of birds. The objective of this study was to analyze temporal and spatial patterns in this condemnation data to gain insight into the ecology and epidemiology of the causative virus. We extracted visual patterns in the data using seasonal trend decomposition, and we tested for statistical significance using extended linear modeling techniques. The analysis confirmed previous findings that there are differences in leukosis condemnation rates between states, across years, and within years. The analysis also revealed several patterns not previously highlighted, including spatial and temporal autocorrelations in leukosis condemnation, changes to the amplitude of seasonality over time, and increasing within-year variation in condemnation rate over time. These patterns suggest that locally shared farm practices, virus transmission between farms, or viral persistence may be important to understanding the dynamics of the disease. We also discuss the plausibility of other potential explanations for these patterns. PMID:25998661

  7. Cortical representation of natural complex sounds: effects of acoustic features and auditory object category

    PubMed Central

    Leaver, Amber M.; Rauschecker, Josef P.

    2010-01-01

    How the brain processes complex sounds, like voices or musical instrument sounds, is currently not well understood. The features comprising the acoustic profiles of such sounds are thought to be represented by neurons responding to increasing degrees of complexity throughout auditory cortex, with complete auditory “objects” encoded by neurons (or small networks of neurons) in anteroventral temporal regions. Although specialized voice and speech-sound regions have been proposed, it is unclear how other types of complex natural sounds are processed within this object-processing pathway. Using functional magnetic resonance imaging (fMRI), we sought to demonstrate spatially distinct patterns of category-selective activity in human auditory cortex, independent of semantic content and low-level acoustic features. Category-selective responses were identified in anterior superior temporal regions, consisting of clusters selective for musical instrument sounds and for human speech. An additional subregion was identified that was particularly selective for the acoustic-phonetic content of speech. In contrast, regions along the superior temporal plane closer to primary auditory cortex were not selective for stimulus category, responding instead to specific acoustic features embedded in natural sounds, such as spectral structure and temporal modulation. Our results support a hierarchical organization of the anteroventral auditory processing stream, with the most anterior regions representing the complete acoustic signature of auditory objects. PMID:20519535

  8. Mean, variance, and temporal coherence of the 3D acoustic field forward propagated through random inhomogeneities in continental-shelf and deep ocean waveguides

    E-print Network

    Chen, Tianrun

    2009-01-01

    When an acoustic field propagates through a multimodal waveguide, the effect of variations in medium properties induced by 3D random inhomogeneities accumulates by multiple forward scattering over range. This causes ...

  9. Temporal and spatial evolution of the large scale meteorological patterns (LSMPs) for California Central Valley hot spells

    NASA Astrophysics Data System (ADS)

    Lee, Y. Y.; Grotjahn, R.

    2014-12-01

    Extreme hot spell events have major impacts on human activities in the California Central Valley (CCV). Previous studies (Grotjahn and Faure 2008; Grotjahn 2011, 2013, 2014) showed that Large Scale Meteorological Patterns (LSMPs) amplify heat over the regional scale CCV. This study diagnoses the temporal and spatial evolution as well as the thermodynamics and dynamics of LSMPs during extreme CCV hot spells. Hot spells begin when at least 6 of 15 CCV stations are in the highest 5% of their normalized daily maximum temperature anomaly (using each station's long term daily mean, LTDM, and LTDM standard deviation). Hot spells must persist at least 3 consecutive days and be separated from other events by 6 days or longer. 22 such events occur during summer (JJAS) 1981-2010. Air parcel trajectories arrive at the critical region for high temperature anomaly from different origins. During the last 4 days leading up to a hot spell onset, air parcels commonly move downward several hundred hPa. Prior to this sinking, two thirds of the parcels (cluster 1) come from the far west (west of 160W) while the rest (cluster 2) from various directions near the CCV. The LSMP evolves as follows: a strong ridge off NE Asia and a stronger trough to the east both upstream of North America, amplify a west coast ridge. In both clusters wave activity flux (WAF) propagates across the North Pacific. In mid to lower troposphere, sinking motion over western North America is coupled to offshore flow. In cluster 1 the upper troposphere WAF off Asia is from the middle and higher latitudes; in the lower troposphere warm anomalies form and amplify along the California coastline. Cluster 2 WAF off Asia is from middle and subtropical latitudes, revealing Rossby wave propagation from the tropics not seen in cluster 1. Also in contrast, warm anomalies in cluster 2 are first prominent off the US/Canada west coast then amplify and expand southward towards California's coast. Objective clustering techniques classify CCV hot spell events based on the evolution of temperature in key parts of the LSMPs. Additional dynamical and adiabatic and diabatic thermal analyses are ongoing and will be shown for each cluster.

  10. Temporal patterns and types of sperm whale (Physeter macrocephalus) codas in the Northern Gulf of Mexico: a metadata analysis

    E-print Network

    Apple, Trent Curtis

    2002-01-01

    Variation in sperm whale codas, short rhythmic series of clicks, was examined across annual, seasonal, and time-of-day temporal categories. Recordings were made from towed linear arrays during two-week seasonal cruises of the Northern Gulf...

  11. A procedure for estimating gestural scores from speech acoustics.

    PubMed

    Nam, Hosung; Mitra, Vikramjit; Tiede, Mark; Hasegawa-Johnson, Mark; Espy-Wilson, Carol; Saltzman, Elliot; Goldstein, Louis

    2012-12-01

    Speech can be represented as a constellation of constricting vocal tract actions called gestures, whose temporal patterning with respect to one another is expressed in a gestural score. Current speech datasets do not come with gestural annotation and no formal gestural annotation procedure exists at present. This paper describes an iterative analysis-by-synthesis landmark-based time-warping architecture to perform gestural annotation of natural speech. For a given utterance, the Haskins Laboratories Task Dynamics and Application (TADA) model is employed to generate a corresponding prototype gestural score. The gestural score is temporally optimized through an iterative timing-warping process such that the acoustic distance between the original and TADA-synthesized speech is minimized. This paper demonstrates that the proposed iterative approach is superior to conventional acoustically-referenced dynamic timing-warping procedures and provides reliable gestural annotation for speech datasets. PMID:23231127

  12. Low Frequency Vibrations Disrupt Left-Right Patterning in the Xenopus Embryo

    Microsoft Academic Search

    Laura N. Vandenberg; Brian W. Pennarola; Michael Levin

    2011-01-01

    The development of consistent left-right (LR) asymmetry across phyla is a fascinating question in biology. While many pharmacological and molecular approaches have been used to explore molecular mechanisms, it has proven difficult to exert precise temporal control over functional perturbations. Here, we took advantage of acoustical vibration to disrupt LR patterning in Xenopus embryos during tightly-circumscribed periods of development. Exposure

  13. An observational study of the temporal and spatial patterns of Marek’s-disease-associated leukosis condemnation of young chickens in the United States of America

    PubMed Central

    Dunn, John R.; Dunn, Patricia A.; Read, Andrew F.

    2015-01-01

    Marek’s disease, a disease primarily affecting immature chickens, is a worldwide problem that has on at least three occasions threatened the poultry industry in the United States. A rich dataset to study the epidemiology of this disease is available because the United States Department of Agriculture has required mandatory inspections of all commercially sold poultry of significant scale since the mid-20th century with over 99% of all chickens inspected. This dataset includes monthly totals aggregated by state since 1961 of the number of “young chickens” inspected and the number with “leukosis”, a condemnation category that is almost always associated with Marek’s disease in this category of birds. The objective of this study was to analyze temporal and spatial patterns in this condemnation data to gain insight into the ecology and epidemiology of the causative virus. We extracted visual patterns in the data using seasonal trend decomposition, and we tested for statistical significance using extended linear modeling techniques. The analysis confirmed previous findings that there are differences in leukosis condemnation rates between states, across years, and within years. The analysis also revealed several patterns not previously highlighted, including spatial and temporal autocorrelations in leukosis condemnation, changes to the amplitude of seasonality over time, and increasing within-year variation in condemnation rate over time. These patterns suggest that locally shared farm practices, virus transmission between farms, or viral persistence may be important to understanding the dynamics of the disease. We also discuss the plausibility of other potential explanations for these patterns. PMID:25998661

  14. Patterns in temporal variability of temperature, oxygen and pH along an environmental gradient in a coral reef.

    PubMed

    Guadayol, Òscar; Silbiger, Nyssa J; Donahue, Megan J; Thomas, Florence I M

    2014-01-01

    Spatial and temporal environmental variability are important drivers of ecological processes at all scales. As new tools allow the in situ exploration of individual responses to fluctuations, ecologically meaningful ways of characterizing environmental variability at organism scales are needed. We investigated the fine-scale spatial heterogeneity of high-frequency temporal variability in temperature, dissolved oxygen concentration, and pH experienced by benthic organisms in a shallow coastal coral reef. We used a spatio-temporal sampling design, consisting of 21 short-term time-series located along a reef flat-to-reef slope transect, coupled to a long-term station monitoring water column changes. Spectral analyses revealed sharp gradients in variance decomposed by frequency, as well as differences between physically-driven and biologically-reactive parameters. These results highlight the importance of environmental variance at organismal scales and present a new sampling scheme for exploring this variability in situ. PMID:24416364

  15. Evaluation of spatial and temporal patterns of insect damage and aflatoxin level in the pre-harvest corn fields to improve management tactics.

    PubMed

    Ni, Xinzhi; Wilson, Jeffrey P; Toews, Michael D; Buntin, G David; Lee, R Dewey; Li, Xin; Lei, Zhongren; He, Kanglai; Xu, Wenwei; Li, Xianchun; Huffaker, Alisa; Schmelz, Eric A

    2014-10-01

    Spatial and temporal patterns of insect damage in relation to aflatoxin contamination in a corn field with plants of uniform genetic background are not well understood. After previous examination of spatial patterns of insect damage and aflatoxin in pre-harvest corn fields, we further examined both spatial and temporal patterns of cob- and kernel-feeding insect damage, and aflatoxin level with two samplings at pre-harvest in 2008 and 2009. The feeding damage by each of the ear/kernel-feeding insects (i.e., corn earworm/fall armyworm damage on the silk/cob, and discoloration of corn kernels by stink bugs) and maize weevil population were assessed at each grid point with five ears. Sampling data showed a field edge effect in both insect damage and aflatoxin contamination in both years. Maize weevils tended toward an aggregated distribution more frequently than either corn earworm or stink bug damage in both years. The frequency of detecting aggregated distribution for aflatoxin level was less than any of the insect damage assessments. Stink bug damage and maize weevil number were more closely associated with aflatoxin level than was corn earworm damage. In addition, the indices of spatial-temporal association (?) demonstrated that the number of maize weevils was associated between the first (4 weeks pre-harvest) and second (1 week pre-harvest) samplings in both years on all fields. In contrast, corn earworm damage between the first and second samplings from the field on the Belflower Farm, and aflatoxin level and corn earworm damage from the field on the Lang Farm were dissociated in 2009. PMID:23956115

  16. Animal-Borne Acoustic Transceivers Reveal Patterns of at-Sea Associations in an Upper-Trophic Level Predator

    PubMed Central

    Lidgard, Damian C.; Bowen, W. Don; Jonsen, Ian D.; Iverson, Sara J.

    2012-01-01

    Satellite telemetry data have substantially increased our understanding of habitat use and foraging behaviour of upper-trophic marine predators, but fall short of providing an understanding of their social behaviour. We sought to determine whether novel acoustic and archival GPS data could be used to examine at-sea associations among grey seals (Halichoerus grypus) during the fall foraging period. Fifteen grey seals from Sable Island, Canada were deployed with Vemco Mobile Transceivers and Satellite-GPS transmitters in October 2009, 13 of which were recaptured and units retrieved 79±2.3 days later during the following breeding season, December 2009–January 2010. An association between two individuals was defined as a cluster of acoustic detections where the time between detections was <30 min. Bathymetry, travel rate, and behavioural state (slow and fast movement) were determined for each GPS archival point (3.7±0.1 locations recorded per hour). Behavioural state was estimated using a hidden Markov model. All seals had been involved in associations with other instrumented seals while at sea, with a total of 1,872 acoustic detections recorded in 201 associations. The median number of detections per association was 3 (range: 1–151) and the median duration of an association was 0.17 h (range: <0.1–11.3 h). Linear mixed-effects models showed that associations occurred when seals were exhibiting slow movement (0.24±0.01 ms?1) on shallow (53.4±3.7 m) offshore banks where dominant prey is known to occur. These results suggest the occurrence of short-term associations among multiple individuals at foraging grounds and provide new insights into the foraging ecology of this upper-trophic marine predator. PMID:23155435

  17. Acoustic stratigraphy of Bear Lake, Utah-Idaho: late Quaternary sedimentation patterns in a simple half-graben

    USGS Publications Warehouse

    Colman, Steven M.

    2006-01-01

    A 277-km network of high-resolution seismic-reflection profiles, supplemented with a sidescan-sonar mosaic of the lake floor, was collected in Bear Lake, Utah–Idaho, in order to explore the sedimentary framework of the lake's paleoclimate record. The acoustic stratigraphy is tied to a 120 m deep, continuously cored drill hole in the lake. Based on the age model for the drill core, the oldest continuously mapped acoustic reflector in the data set has an age of about 100 ka, although older sediments were locally imaged. The acoustic stratigraphy of the sediments below the lake indicates that the basin developed primarily as a simple half-graben, with a steep normal-fault margin on the east and a flexural margin on the west. As expected for a basin controlled by a listric master fault, seismic reflections steepen and diverge toward the fault, bounding eastward-thickening sediment wedges. Secondary normal faults west of the master fault were imaged beneath the lake and many of these faults show progressively increasing offset with depth and age. Several faults cut the youngest sediments in the lake as well as the modern lake floor. The relative simplicity of the sedimentary sequence is interrupted in the northwestern part of the basin by a unit that is interpreted as a large (4 × 10 km) paleodelta of the Bear River. The delta overlies a horizon with an age of about 97 ka, outcrops at the lake floor and is onlapped by much of the uppermost sequence of lake sediments. A feature interpreted as a wave-cut bench occurs in many places on the western side of the lake. The base of this bench occurs at a depth (22–24 m) similar to that (20–25 m) of the distal surface of the paleodelta. Pinch-outs of sedimentary units are common in relatively shallow water on the gentle western margin of the basin and little Holocene sediment has accumulated in water depths of less than 30 m. On the steep eastern margin of the basin, sediments commonly onlap the hanging wall of the East Bear Lake Fault. However, no major erosional or depositional features suggestive of shoreline processes were observed on acoustic profiles in water deeper than about 20–25 m.

  18. Time-warp invariant pattern detection with bursting neurons

    NASA Astrophysics Data System (ADS)

    Gollisch, Tim

    2008-01-01

    Sound patterns are defined by the temporal relations of their constituents, individual acoustic cues. Auditory systems need to extract these temporal relations to detect or classify sounds. In various cases, ranging from human speech to communication signals of grasshoppers, this pattern detection has been found to display invariance to temporal stretching or compression of the sound signal ('linear time-warp invariance'). In this work, a four-neuron network model is introduced, designed to solve such a detection task for the example of grasshopper courtship songs. As an essential ingredient, the network contains neurons with intrinsic bursting dynamics, which allow them to encode durations between acoustic events in short, rapid sequences of spikes. As shown by analytical calculations and computer simulations, these neuronal dynamics result in a powerful mechanism for temporal integration. Finally, the network reads out the encoded temporal information by detecting equal activity of two such bursting neurons. This leads to the recognition of rhythmic patterns independent of temporal stretching or compression.

  19. Primate drum kit: a system for studying acoustic pattern production by non-human primates using acceleration and strain sensors.

    PubMed

    Ravignani, Andrea; Matellán Olivera, Vicente; Gingras, Bruno; Hofer, Riccardo; Rodríguez Hernández, Carlos; Sonnweber, Ruth-Sophie; Fitch, W Tecumseh

    2013-01-01

    The possibility of achieving experimentally controlled, non-vocal acoustic production in non-human primates is a key step to enable the testing of a number of hypotheses on primate behavior and cognition. However, no device or solution is currently available, with the use of sensors in non-human animals being almost exclusively devoted to applications in food industry and animal surveillance. Specifically, no device exists which simultaneously allows: (i) spontaneous production of sound or music by non-human animals via object manipulation, (ii) systematical recording of data sensed from these movements, (iii) the possibility to alter the acoustic feedback properties of the object using remote control. We present two prototypes we developed for application with chimpanzees (Pan troglodytes) which, while fulfilling the aforementioned requirements, allow to arbitrarily associate sounds to physical object movements. The prototypes differ in sensing technology, costs, intended use and construction requirements. One prototype uses four piezoelectric elements embedded between layers of Plexiglas and foam. Strain data is sent to a computer running Python through an Arduino board. A second prototype consists in a modified Wii Remote contained in a gum toy. Acceleration data is sent via Bluetooth to a computer running Max/MSP. We successfully pilot tested the first device with a group of chimpanzees. We foresee using these devices for a range of cognitive experiments. PMID:23912427

  20. Spatial and temporal patterns of carabid activity-density in cereals do not explain levels of predation on weed seeds

    Microsoft Academic Search

    P. Saska; W. van der Werf; E. de Vries; P. R. Westerman

    2008-01-01

    Seed predation is an important component of seed mortality of weeds in agro-ecosystems, but the agronomic use and management of this natural weed suppression is hampered by a lack of insight in the underlying ecological processes. In this paper, we investigate whether and how spatial and temporal variation in activity-density of granivorous ground beetles (Coleoptera: Carabidae) results in a corresponding

  1. Spatial and temporal patterns in the aquatic insect community of a high altitude Andean stream (Mendoza, Argentina)

    Microsoft Academic Search

    Erica E. Scheibler; Guillermo O. Debandi

    2008-01-01

    Benthic invertebrate communities have been poorly studied in Andean streams apart from the Patagonian region. The primary objective of this work was to analyse the faunal composition at three different altitudes and to observe whether there were differences in aquatic insect community structure at spatial and temporal scales. Physicochemical variables were measured on a monthly basis. Sixteen families were found,

  2. Spatial, spectral and temporal patterns of tropical forest cover change as observed with multiple scales of optical satellite data

    Microsoft Academic Search

    Daniel J. Hayes; Warren B. Cohen

    2007-01-01

    This article describes the development of a methodology for scaling observations of changes in tropical forest cover to large areas at high temporal frequency from coarse resolution satellite imagery. The approach for estimating proportional forest cover change as a continuous variable is based on a regression model that relates multispectral, multitemporal MODIS data, transformed to optimize the spectral detection of

  3. Cluster Analysis in Sociometric Research: A Pattern-Oriented Approach to Identifying Temporally Stable Peer Status Groups of Girls

    ERIC Educational Resources Information Center

    Zettergren, Peter

    2007-01-01

    A modern clustering technique was applied to age-10 and age-13 sociometric data with the purpose of identifying longitudinally stable peer status clusters. The study included 445 girls from a Swedish longitudinal study. The identified temporally stable clusters of rejected, popular, and average girls were essentially larger than corresponding…

  4. Innovative sensing techniques and data analysis for characterizing the spatial and temporal dynamics of soil moisture patterns at the hillslope scale

    NASA Astrophysics Data System (ADS)

    Martini, Edoardo; Wollschläger, Ute; Kögler, Simon; Behrens, Thorsten; Dietrich, Peter; Reinstorf, Frido; Schmidt, Karsten; Weiler, Markus; Werban, Ulrike; Zacharias, Steffen

    2015-04-01

    Soil moisture plays a critical role in every hydrological or meteorological model; nevertheless, it is still a great challenge to provide adequate information on soil moisture distribution beyond the point scale. Mobile geophysical methods such as electromagnetic induction (EMI) have been widely used for mapping soil water content at the field scale with high spatial resolution. Recent advances in wireless sensor technology allow monitoring of soil moisture dynamics with high temporal resolution at varying scales. The objective of this study was to characterize the spatio-temporal pattern of soil moisture at the hillslope scale and infer the controlling hydrological processes, integrating well established and innovative sensing techniques, as well as new statistical methods. We combined soil hydrological and pedological expertise with geophysical measurements and methods from digital soil mapping for designing the monitoring setup of a wireless sensor network for a grassland hillslope in the Schäfertal catchment, Central Germany. At the same site, we measured soil apparent electrical conductivity (ECa) using EMI devices. Hypothesizing a wet and a dry soil moisture state to be characteristic of the spatial pattern of soil moisture, we tested a new method of analysis based on the Spearman rank correlation coefficient for describing the spatial and temporal evolution of such patterns. Based on this approach, we described the persistence and switching mechanisms of the two characteristic states, inferring the local properties that control the observed spatial patterns and the hydrological processes driving the transitions. The method showed to provide valuable insight into the persistence of characteristic states of soil moisture and the mechanisms of transition, and to be suitable for highlighting events for which specific hydrological processes occurred. The spatial organization of soil moisture was observed to be controlled by different processes in different soil horizons, with time-varying contribution, and the topsoil's moisture does not mirror processes that take place within the soil profile. The EMI investigation at the Schäfertal site appears to be suitable for mapping soil moisture at times when local soil properties control the spatial distribution of soil moisture, but not when topography has a major control on such pattern. The results will help to improve conceptual understanding for hydrological model studies at similar or smaller scales, and to transfer observation concepts and process understanding to larger or less instrumented areas.

  5. An examination of the temporal and geographical patterns of psychiatric emergency service use by multiple visit patients as a means for their early detection

    PubMed Central

    Chaput, Yves JA; Lebel, Marie-Josée

    2007-01-01

    Background: Frequent users of the psychiatric emergency service (PES) place a heavy burden upon the mental health care delivery system. The aim of this study was to identify distinct temporal or geographical patterns of PES use by these patients as potential markers for their early detection. Methods: Diagnostic profiles were obtained for patients making an intermediate (4 to 10) or a high (11 or more) number of visits to a general hospital PES in Montreal (Canada) between 1985 and 2004. Between-group comparisons were made with regards to several parameters. These included the time intervals between consecutive visits, visit clustering (single, repeating, and the time interval to the first cluster) and visits made to three other services where data was similarly acquired from 2002 to 2004. Results: The two multiple visit groups differed with regards to diagnostic profiles and actual time between consecutive visits (significantly shorter in patients with 11 or more visits). Patients with 11 or more visits were more likely to have a single cluster (3 or more visits/3 months) or repeating clusters (4 visits/3 months) in their patterns of use. Personality disorders were more prevalent in patients with single clusters as they were, along with schizophrenia, in those with repeating clusters. In addition, clusters were found to occur sufficiently early so as to be potentially useful as markers for early detection. Ten percent of those with 11 or more visits and 16% of those with an intermediate number of visits frequented at least one other PES. A small number of patients, primarily those with substance abuse, made over 50% of their visits to other services. Conclusion: Temporal and geographical patterns of use differed significantly between the multiple visit groups. These patterns, combined with distinct diagnostic profiles, could potentially lead to the more rapid identification and treatment of specific sub-groups of multiple visit patients. PMID:17963530

  6. Noise-robust acoustic signature recognition using nonlinear Hebbian learning

    Microsoft Academic Search

    Bing Lu; Alireza A. Dibazar; Theodore W. Berger

    2010-01-01

    We propose using a new biologically inspired approach, nonlinear Hebbian learning (NHL), to implement acoustic signal recognition in noisy environments. The proposed learning processes both spectral and temporal features of input acoustic data. The spectral analysis is realized by using auditory gammatone filterbanks. The temporal dynamics is addressed by analyzing gammatone-filtered feature vectors over multiple temporal frames, which is called

  7. Linking spatio-temporal patterns in land cover dynamics with regional climate factors and recent weather: Application to the Flint Hills of Kansas and Oklahoma

    SciTech Connect

    Henebry, G.M.; Goodin, D.G. [Kansas State Univ., Manhattan, KS (United States); Su, H. [Argonne National Lab., IL (United States)] [and others

    1995-06-01

    A key obstacle to developing regional models of ecosystem dynamics is representation of spatio-temporal variation in constituent patterns and processes. Simple resealing of site-specific ecological data or simulations to broader spatial scales is unlikely to capture regional spatio-temporal dynamics. Yet logistical constraints usually require synoptic weather data to be synthesized from sparse data networks. We seek a simple top-down model that links remotely-sensed vegetation cover with antecedent meteorological forcings to generate boundary conditions for site-specific fine-resolution data and simulations of tallgrass prairie. We developed several candidate models using AVHRR NDVI maximum biweekly composites of the Flint Hills from 1990-1993 and data from a network of more than 60 weather stations across the 40,000 km2 region. Models combined parameters derived from exemplary land cover trajectories, spatial structure (lacunarity and correlation length), and running weighted sums of weather data. Spectral-temporal models were easier to fit; lacunarity was more sensitive than correlation length; compositing effects were strong.

  8. Assessment of long-range correlation in animal behavior time series: The temporal pattern of locomotor activity of Japanese quail (Coturnix coturnix) and mosquito larva (Culex quinquefasciatus)

    NASA Astrophysics Data System (ADS)

    Kembro, Jackelyn M.; Flesia, Ana Georgina; Gleiser, Raquel M.; Perillo, María A.; Marin, Raul H.

    2013-12-01

    Detrended Fluctuation Analysis (DFA) is a method that has been frequently used to determine the presence of long-range correlations in human and animal behaviors. However, according to previous authors using statistical model systems, in order to correctly use DFA different aspects should be taken into account such as: (1) the establishment by hypothesis testing of the absence of short term correlation, (2) an accurate estimation of a straight line in the log-log plot of the fluctuation function, (3) the elimination of artificial crossovers in the fluctuation function, and (4) the length of the time series. Taking into consideration these factors, herein we evaluated the presence of long-range correlation in the temporal pattern of locomotor activity of Japanese quail (Coturnix coturnix) and mosquito larva (Culex quinquefasciatus). In our study, modeling the data with the general autoregressive integrated moving average (ARFIMA) model, we rejected the hypothesis of short-range correlations (d=0) in all cases. We also observed that DFA was able to distinguish between the artificial crossover observed in the temporal pattern of locomotion of Japanese quail and the crossovers in the correlation behavior observed in mosquito larvae locomotion. Although the test duration can slightly influence the parameter estimation, no qualitative differences were observed between different test durations.

  9. Acrylamide exposure induces a delayed unscheduled DNA synthesis in germ cells of male mice that is correlated with the temporal pattern of adduct formation in testis DNA

    SciTech Connect

    Sega, G.A.; Generoso, E.E.; Brimer, P.A. (Oak Ridge National Laboratory, TN (USA))

    1990-01-01

    A study of meiotic and postmeiotic germ-cell-stage sensitivity of male mice to induction of unscheduled DNA synthesis (UDS) by acrylamide showed that DNA repair could be detected in early spermatocytes (after the last scheduled DNA synthesis) through about mid-spermatid stages. No DNA repair could be detected in later stages. The maximum UDS response was observed 6 hr after i.p. exposure and was about 5 times greater than the response measured immediately after treatment. This is the longest delay between chemical treatment and maximum UDS response yet observed in mouse germ cells. There was a linear relationship between the UDS response and acrylamide exposure from 7.8 to 125 mg/kg. By using 14C-labeled acrylamide it was determined that the temporal pattern of adduct formation in testes DNA paralleled that of the UDS response, with maximum binding occurring 4 to 6 hr after exposure. In contrast, the temporal pattern of adduct formation in liver DNA showed maximum binding within 1 to 2 hr after exposure and was an order of magnitude greater than that found for the testis DNA.

  10. Study of perkinsosis in the carpet shell clam Tapes decussatus in Galicia (NW Spain). II. Temporal pattern of disease dynamics and association with clam mortality.

    PubMed

    Villalba, Antonio; Casas, Sandra M; López, Carmen; Carballal, María J

    2005-07-18

    Temporal dynamics of the infection by Perkinsus olseni in a clam (Tapes decussatus) bed was studied over 5 yr (March 1996 to December 2000). Diagnostic techniques were compared to assess their suitability for epizootiological purposes. A technique based on incubation of 2 gill lamellae in Ray's fluid thioglycollate medium (RFTM) was more sensitive, quicker and cheaper than examination of histological sections. Incubation of the whole-clam soft tissues in RFTM allowed detection of very light infections that were not detected with incubation of only 2 gill lamellae. Nevertheless, the correlation between the infection intensity estimated by both RFTM incubations was high. Infection intensity was significantly and positively correlated with clam size/age. No infected clam smaller than 20 mm was found. There was an annual pattern of infection involving lower mean infection intensity and prevalence in winter and higher values for both variables from spring to autumn, with 2 main annual peaks in spring and late summer-early autumn. This temporal pattern was significantly associated with the seawater temperature. The annual spring peak of infection intensity occurred when seawater temperature was around 15 degrees C. Monthly mortality in the clam bed peaked in spring and summer--after peaks of P. olseni infection intensity and concurrently with high seawater temperature. A comparison of percentage mortality between clams from 2 sources (a perkinsosis-affected and a non-affected area) placed in the same clam bed revealed significantly higher mortality in the clams originating from the perkinsosis-affected area. PMID:16119895

  11. Predictors of temporal patterns of psychiatric distress during 10 years following the nuclear accident at Three Mile Island.

    PubMed

    Dew, M A; Bromet, E J

    1993-04-01

    The present study examines psychiatric symptom levels during a 10-year period in a community sample of mothers of young children. All were identified in the early aftermath of the 1979 Three Mile Island nuclear accident, and followed through the accident's 1989 anniversary. Cluster analysis was used to identify long-term distress profiles during the study period; women's temporal profiles were found to be either (a) stable and at low, clinically nonsignificant levels of distress across all measurement points or (b) at consistently elevated, clinically significant levels that varied with the timing of postaccident events such as the restart of the undamaged reactor and the 10th anniversary. Subsequent multivariate analyses indicated that preaccident characteristics, as well as parameters reflecting respondents' initial involvement with, and reactions to the accident, were important for distinguishing between women within the two temporal profile groups. Implications of the results for both policy formulation and continued research on significant environmental stressors is discussed. PMID:8511662

  12. Quantifying Temporal Documentation Patterns in Clinician Use of AHLTA—the DoD’s Ambulatory Electronic Health Record

    PubMed Central

    Bohnsack, Kevin J.; Parker, David P.; Zheng, Kai

    2009-01-01

    In this paper, we analyzed computer-recorded user interactions with AHLTA, the electronic health record (EHR) used by the Department of Defense, to study clinicians’ temporal documentation behavior in their use of the system in their daily clinical practice. We collected one week of AHLTA usage data via a monitoring software program installed in 35,570 clinical workstations across 138 military treatment facilities. The data allowed us to quantify the temporal relations among sentinel events that represent two distinct phases of clinical documentation: initiating a patient encounter and finalizing the patient note. The results suggest that alternative EHR documentation strategies such as deferred documentation were commonly employed by clinicians. The incidence rates of encounter initiation and finalization were significantly disproportional across time of day. Lunchtime and late afternoon catch-up activities were clearly delineated. While alternative documentation is a known tactic employed by clinicians, it has not been rigorously quantified in previous research. PMID:20351821

  13. Spatio-temporal patterns and source apportionment of pollution in Qiantang River (China) using neural-based modeling and multivariate statistical techniques

    NASA Astrophysics Data System (ADS)

    Su, Shiliang; Zhi, Junjun; Lou, Liping; Huang, Fang; Chen, Xia; Wu, Jiaping

    Characterizing the spatio-temporal patterns and apportioning the pollution sources of water bodies are important for the management and protection of water resources. The main objective of this study is to describe the dynamics of water quality and provide references for improving river pollution control practices. Comprehensive application of neural-based modeling and different multivariate methods was used to evaluate the spatio-temporal patterns and source apportionment of pollution in Qiantang River, China. Measurement data were obtained and pretreated for 13 variables from 41 monitoring sites for the period of 2001-2004. A self-organizing map classified the 41 monitoring sites into three groups (Group A, B and C), representing different pollution characteristics. Four significant parameters (dissolved oxygen, biochemical oxygen demand, total phosphorus and total lead) were identified by discriminant analysis for distinguishing variations of different years, with about 80% correct assignment for temporal variation. Rotated principal component analysis (PCA) identified four potential pollution sources for Group A (domestic sewage and agricultural pollution, industrial wastewater pollution, mineral weathering, vehicle exhaust and sand mining), five for Group B (heavy metal pollution, agricultural runoff, vehicle exhaust and sand mining, mineral weathering, chemical plants discharge) and another five for Group C (vehicle exhaust and sand mining, chemical plants discharge, soil weathering, biochemical pollution, mineral weathering). The identified potential pollution sources explained 75.6% of the total variances for Group A, 75.0% for Group B and 80.0% for Group C, respectively. Receptor-based source apportionment was applied to further estimate source contributions for each pollution variable in the three groups, which facilitated and supported the PCA results. These results could assist managers to develop optimal strategies and determine priorities for river pollution control and effective water resources management.

  14. Transmission of spatio-temporal patterns from biological to artificial neural networks by a multi-electrode array

    Microsoft Academic Search

    Andreas Herzog; Karsten Kube; Bernd Michaelis; Ana D. De Lima; Thomas Baltz; Thomas B. Voigt

    2008-01-01

    The monitoring of a set of individual neurons in cultured biological networks or in the brain has become feasible with the used\\/development of multi-electrode arrays (MEA). However, even with the huge mass of data, getting suitable information about the actual spatio-temporal context of the analyzed biological network is not easy. In this paper we present a new conception and first

  15. Radiometric correction of multi-temporal Landsat data for characterization of early successional forest patterns in western Oregon

    Microsoft Academic Search

    Todd A. Schroeder; Warren B. Cohen; Conghe Song; Morton J. Canty; Zhiqiang Yang

    2006-01-01

    Detecting and characterizing continuous changes in early forest succession using multi-temporal satellite imagery requires atmospheric correction procedures that are both operationally reliable, and that result in comparable units (e.g., surface reflectance). This paper presents a comparison of five atmospheric correction methods (2 relative, 3 absolute) used to correct a nearly continuous 20-year Landsat TM\\/ETM+ image data set (19-images) covering western

  16. Time-resolved coherent X-ray diffraction imaging of surface acoustic waves

    PubMed Central

    Nicolas, Jan-David; Reusch, Tobias; Osterhoff, Markus; Sprung, Michael; Schülein, Florian J. R.; Krenner, Hubert J.; Wixforth, Achim; Salditt, Tim

    2014-01-01

    Time-resolved coherent X-ray diffraction experiments of standing surface acoustic waves, illuminated under grazing incidence by a nanofocused synchrotron beam, are reported. The data have been recorded in stroboscopic mode at controlled and varied phase between the acoustic frequency generator and the synchrotron bunch train. At each time delay (phase angle), the coherent far-field diffraction pattern in the small-angle regime is inverted by an iterative algorithm to yield the local instantaneous surface height profile along the optical axis. The results show that periodic nanoscale dynamics can be imaged at high temporal resolution in the range of 50?ps (pulse length). PMID:25294979

  17. Monitoring acoustically tagged king prawns Penaeus ( Melicertus ) plebejus in an estuarine lagoon

    Microsoft Academic Search

    Matthew D. Taylor; Anthony Ko

    2011-01-01

    Fine-scale movement patterns in penaeid prawns are rarely observed in situ, but are essential in understanding habitat use,\\u000a foraging, and anti-predator behaviour. Acoustic telemetry was applied to examine the activity, space utilization, and habitat\\u000a use of the eastern king prawn Penaeus (Melicertus) plebejus, at small temporal and spatial scales. Tracking of sub-adult P. plebejus (n = 9) in Wallagoot Lake (36.789°S, 149.959°E; 23

  18. Temporal patterns of Campylobacter contamination on chicken and their relationship to campylobacteriosis cases in the United States.

    PubMed

    Williams, Michael S; Golden, Neal J; Ebel, Eric D; Crarey, Emily T; Tate, Heather P

    2015-09-01

    The proportion of Campylobacter contaminated food and water samples collected by different surveillance systems often exhibit seasonal patterns. In addition, the incidence of foodborne campylobacteriosis also tends to exhibit strong seasonal patterns. Of the various product classes, the occurrence of Campylobacter contamination can be high on raw poultry products, and chicken is often thought to be one of the leading food vehicles for campylobacteriosis. Two different federal agencies in the United States collected samples of raw chicken products and tested them for the presence of Campylobacter. During the same time period, a consortium of federal and state agencies operated a nationwide surveillance system to monitor cases of campylobacteriosis in the United States. This study uses a common modeling approach to estimate trends and seasonal patterns in both the proportion of raw chicken product samples that test positive for Campylobacter and cases of campylobacteriosis. The results generally support the hypothesis of a weak seasonal increase in the proportion of Campylobacter positive chicken samples in the summer months, though the number of Campylobacter on test-positive samples is slightly lower during this time period. In contrast, campylobacteriosis cases exhibit a strong seasonal pattern that generally precedes increases in contaminated raw chicken. These results suggest that while contaminated chicken products may be responsible for a substantial number of campylobacteriosis cases, they are most likely not the primary driver of the seasonal pattern in human illness. PMID:26065728

  19. Seasonal physical-chemical structure and acoustic Doppler current profiler flow patterns over multiple years in a shallow, stratified estuary, with implications for lateral variability

    NASA Astrophysics Data System (ADS)

    Reed, Robert E.; Glasgow, Howard B.; Burkholder, JoAnn M.; Brownie, Cavell

    2004-08-01

    The overall goal of this study was to strengthen understanding of the hydrographic structure in shallow estuaries as influenced by seasonal and depth-dependent variability, and by variability from extreme meteorological events. The mesohaline Neuse Estuary, North Carolina, U.S.A., which was the focus, receives surface inputs from upriver and tributary freshwater sources and bottom inputs from downriver high-salinity sound water sources, resulting in varying degrees of stratification. To assess depth-dependent, estuary-wide changes in salinity, a multiple time series was created using data from four discrete depths (surface and 1, 2, and 3 m±0.25 m). The database was developed from weekly to biweekly sampling of the entire water column, and included side-channel as well as mid-channel data. We characterized seasonal differences in halocline depth affecting the hydrographic structure of the mesohaline estuary and site-specific variation in nutrient concentrations, based on a comprehensive eight-year physical/chemical database. The first two years of the record showed an expected seasonal signal and included events that impacted the surface layer from freshwater inputs. Remaining years had greater variability over seasons and depths, with freshening events that affected all depths. Halocline depth was compared at specific locations, and a "snapshot" view was provided of the relative depth of these water masses within the estuary by season. We also examined flow patterns at the same cross-estuary sites over a three-year period, using a boat-mounted acoustic Doppler current profiler (ADCP) with bottom-tracking capability. Composite visualizations constructed with single-transect ADCP data revealed a classical estuarine circulation pattern of outflow at the surface/southern shore and inflow at the bottom/northern shore. Although this pattern deviated under extreme climatological events and was sometimes variable, the estuary generally exhibited a high probability of direction of flow. Wind fields, hurricanes, and small-scale, high-precipitation events represented significant forcing variables.

  20. Effects of spectral and temporal disruption on cortical encoding of gerbil vocalizations

    PubMed Central

    Ter-Mikaelian, Maria; Semple, Malcolm N.

    2013-01-01

    Animal communication sounds contain spectrotemporal fluctuations that provide powerful cues for detection and discrimination. Human perception of speech is influenced both by spectral and temporal acoustic features but is most critically dependent on envelope information. To investigate the neural coding principles underlying the perception of communication sounds, we explored the effect of disrupting the spectral or temporal content of five different gerbil call types on neural responses in the awake gerbil's primary auditory cortex (AI). The vocalizations were impoverished spectrally by reduction to 4 or 16 channels of band-passed noise. For this acoustic manipulation, an average firing rate of the neuron did not carry sufficient information to distinguish between call types. In contrast, the discharge patterns of individual AI neurons reliably categorized vocalizations composed of only four spectral bands with the appropriate natural token. The pooled responses of small populations of AI cells classified spectrally disrupted and natural calls with an accuracy that paralleled human performance on an analogous speech task. To assess whether discharge pattern was robust to temporal perturbations of an individual call, vocalizations were disrupted by time-reversing segments of variable duration. For this acoustic manipulation, cortical neurons were relatively insensitive to short reversal lengths. Consistent with human perception of speech, these results indicate that the stable representation of communication sounds in AI is more dependent on sensitivity to slow temporal envelopes than on spectral detail. PMID:23761696