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Sample records for acoustics temporal patterns

  1. Temporal pattern of acoustic imaging noise asymmetrically modulates activation in the auditory cortex.

    PubMed

    Ranaweera, Ruwan D; Kwon, Minseok; Hu, Shuowen; Tamer, Gregory G; Luh, Wen-Ming; Talavage, Thomas M

    2016-01-01

    This study investigated the hemisphere-specific effects of the temporal pattern of imaging related acoustic noise on auditory cortex activation. Hemodynamic responses (HDRs) to five temporal patterns of imaging noise corresponding to noise generated by unique combinations of imaging volume and effective repetition time (TR), were obtained using a stroboscopic event-related paradigm with extra-long (≥27.5 s) TR to minimize inter-acquisition effects. In addition to confirmation that fMRI responses in auditory cortex do not behave in a linear manner, temporal patterns of imaging noise were found to modulate both the shape and spatial extent of hemodynamic responses, with classically non-auditory areas exhibiting responses to longer duration noise conditions. Hemispheric analysis revealed the right primary auditory cortex to be more sensitive than the left to the presence of imaging related acoustic noise. Right primary auditory cortex responses were significantly larger during all the conditions. This asymmetry of response to imaging related acoustic noise could lead to different baseline activation levels during acquisition schemes using short TR, inducing an observed asymmetry in the responses to an intended acoustic stimulus through limitations of dynamic range, rather than due to differences in neuronal processing of the stimulus. These results emphasize the importance of accounting for the temporal pattern of the acoustic noise when comparing findings across different fMRI studies, especially those involving acoustic stimulation.

  2. Temporal pattern of acoustic imaging noise asymmetrically modulates activation in the auditory cortex

    PubMed Central

    Ranaweera, Ruwan D.; Kwon, Minseok; Hu, Shuowen; Tamer, Gregory G.; Luh, Wen-Ming; Talavage, Thomas M.

    2015-01-01

    This study investigated the hemisphere-specific effects of the temporal pattern of imaging related acoustic noise on auditory cortex activation. Hemodynamic responses (HDRs) to five temporal patterns of imaging noise corresponding to noise generated by unique combinations of imaging volume and effective repetition time (TR), were obtained using a stroboscopic event-related paradigm with extra-long (≥27.5s) TR to minimize inter-acquisition effects. In addition to confirmation that fMRI responses in auditory cortex do not behave in a linear manner, temporal patterns of imaging noise were found to modulate both the shape and spatial extent of hemodynamic responses, with classically non-auditory areas exhibiting responses to longer duration noise conditions. Hemispheric analysis revealed the right primary auditory cortex to be more sensitive than the left to the presence of imaging related acoustic noise. Right primary auditory cortex responses were significantly larger during all the conditions. This asymmetry of response to imaging related acoustic noise could lead to different baseline activation levels during acquisition schemes using short TR, inducing an observed asymmetry in the responses to an intended acoustic stimulus through limitations of dynamic range, rather than due to differences in neuronal processing of the stimulus. These results emphasize the importance of accounting for the temporal pattern of the acoustic noise when comparing findings across different fMRI studies, especially those involving acoustic stimulation. PMID:26519093

  3. 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

  4. Long Term Memory for Noise: Evidence of Robust Encoding of Very Short Temporal Acoustic Patterns

    PubMed Central

    Viswanathan, Jayalakshmi; Rémy, Florence; Bacon-Macé, Nadège; Thorpe, Simon J.

    2016-01-01

    Recent research has demonstrated that humans are able to implicitly encode and retain repeating patterns in meaningless auditory noise. Our study aimed at testing the robustness of long-term implicit recognition memory for these learned patterns. Participants performed a cyclic/non-cyclic discrimination task, during which they were presented with either 1-s cyclic noises (CNs) (the two halves of the noise were identical) or 1-s plain random noises (Ns). Among CNs and Ns presented once, target CNs were implicitly presented multiple times within a block, and implicit recognition of these target CNs was tested 4 weeks later using a similar cyclic/non-cyclic discrimination task. Furthermore, robustness of implicit recognition memory was tested by presenting participants with looped (shifting the origin) and scrambled (chopping sounds into 10− and 20-ms bits before shuffling) versions of the target CNs. We found that participants had robust implicit recognition memory for learned noise patterns after 4 weeks, right from the first presentation. Additionally, this memory was remarkably resistant to acoustic transformations, such as looping and scrambling of the sounds. Finally, implicit recognition of sounds was dependent on participant's discrimination performance during learning. Our findings suggest that meaningless temporal features as short as 10 ms can be implicitly stored in long-term auditory memory. Moreover, successful encoding and storage of such fine features may vary between participants, possibly depending on individual attention and auditory discrimination abilities. Significance Statement Meaningless auditory patterns could be implicitly encoded and stored in long-term memory.Acoustic transformations of learned meaningless patterns could be implicitly recognized after 4 weeks.Implicit long-term memories can be formed for meaningless auditory features as short as 10 ms.Successful encoding and long-term implicit recognition of meaningless patterns may

  5. In-situ optical and acoustical measurements of the buoyant cyanobacterium p. Rubescens: spatial and temporal distribution patterns.

    PubMed

    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.

  6. Temporal patterns in the acoustic signals of beaked whales at Cross Seamount.

    PubMed

    Johnston, D W; McDonald, M; Polovina, J; Domokos, R; Wiggins, S; Hildebrand, J

    2008-04-23

    Seamounts may influence the distribution of marine mammals through a combination of increased ocean mixing, enhanced local productivity and greater prey availability. To study the effects of seamounts on the presence and acoustic behaviour of cetaceans, we deployed a high-frequency acoustic recording package on the summit of Cross Seamount during April through October 2005. The most frequently detected cetacean vocalizations were echolocation sounds similar to those produced by ziphiid and mesoplodont beaked whales together with buzz-type signals consistent with prey-capture attempts. Beaked whale signals occurred almost entirely at night throughout the six-month deployment. Measurements of prey presence with a Simrad EK-60 fisheries acoustics echo sounder indicate that Cross Seamount may enhance local productivity in near-surface waters. Concentrations of micronekton were aggregated over the seamount in near-surface waters at night, and dense concentrations of nekton were detected across the surface of the summit. Our results suggest that seamounts may provide enhanced foraging opportunities for beaked whales during the night through a combination of increased productivity, vertical migrations by micronekton and local retention of prey. Furthermore, the summit of the seamount may act as a barrier against which whales concentrate prey.

  7. The Curious Acoustic Behavior of Estuarine Snapping Shrimp: Temporal Patterns of Snapping Shrimp Sound in Sub-Tidal Oyster Reef Habitat.

    PubMed

    Bohnenstiehl, DelWayne R; Lillis, Ashlee; Eggleston, David B

    2016-01-01

    Ocean soundscapes convey important sensory information to marine life. Like many mid-to-low latitude coastal areas worldwide, the high-frequency (>1.5 kHz) soundscape of oyster reef habitat within the West Bay Marine Reserve (36°N, 76°W) is dominated by the impulsive, short-duration signals generated by snapping shrimp. Between June 2011 and July 2012, a single hydrophone deployed within West Bay was programmed to record 60 or 30 seconds of acoustic data every 15 or 30 minutes. Envelope correlation and amplitude information were then used to count shrimp snaps within these recordings. The observed snap rates vary from 1500-2000 snaps per minute during summer to <100 snaps per minute during winter. Sound pressure levels are positively correlated with snap rate (r = 0.71-0.92) and vary seasonally by ~15 decibels in the 1.5-20 kHz range. Snap rates are positively correlated with water temperatures (r = 0.81-0.93), as well as potentially influenced by climate-driven changes in water quality. Light availability modulates snap rate on diurnal time scales, with most days exhibiting a significant preference for either nighttime or daytime snapping, and many showing additional crepuscular increases. During mid-summer, the number of snaps occurring at night is 5-10% more than predicted by a random model; however, this pattern is reversed between August and April, with an excess of up to 25% more snaps recorded during the day in the mid-winter. Diurnal variability in sound pressure levels is largest in the mid-winter, when the overall rate of snapping is at its lowest, and the percentage difference between daytime and nighttime activity is at its highest. This work highlights our lack of knowledge regarding the ecology and acoustic behavior of one of the most dominant soniforous invertebrate species in coastal systems. It also underscores the necessity of long-duration, high-temporal-resolution sampling in efforts to understand the bioacoustics of animal behaviors and

  8. The Curious Acoustic Behavior of Estuarine Snapping Shrimp: Temporal Patterns of Snapping Shrimp Sound in Sub-Tidal Oyster Reef Habitat

    PubMed Central

    Bohnenstiehl, DelWayne R.; Lillis, Ashlee; Eggleston, David B.

    2016-01-01

    Ocean soundscapes convey important sensory information to marine life. Like many mid-to-low latitude coastal areas worldwide, the high-frequency (>1.5 kHz) soundscape of oyster reef habitat within the West Bay Marine Reserve (36°N, 76°W) is dominated by the impulsive, short-duration signals generated by snapping shrimp. Between June 2011 and July 2012, a single hydrophone deployed within West Bay was programmed to record 60 or 30 seconds of acoustic data every 15 or 30 minutes. Envelope correlation and amplitude information were then used to count shrimp snaps within these recordings. The observed snap rates vary from 1500–2000 snaps per minute during summer to <100 snaps per minute during winter. Sound pressure levels are positively correlated with snap rate (r = 0.71–0.92) and vary seasonally by ~15 decibels in the 1.5–20 kHz range. Snap rates are positively correlated with water temperatures (r = 0.81–0.93), as well as potentially influenced by climate-driven changes in water quality. Light availability modulates snap rate on diurnal time scales, with most days exhibiting a significant preference for either nighttime or daytime snapping, and many showing additional crepuscular increases. During mid-summer, the number of snaps occurring at night is 5–10% more than predicted by a random model; however, this pattern is reversed between August and April, with an excess of up to 25% more snaps recorded during the day in the mid-winter. Diurnal variability in sound pressure levels is largest in the mid-winter, when the overall rate of snapping is at its lowest, and the percentage difference between daytime and nighttime activity is at its highest. This work highlights our lack of knowledge regarding the ecology and acoustic behavior of one of the most dominant soniforous invertebrate species in coastal systems. It also underscores the necessity of long-duration, high-temporal-resolution sampling in efforts to understand the bioacoustics of animal behaviors

  9. Representations of specific acoustic patterns in the auditory cortex and hippocampus.

    PubMed

    Kumar, Sukhbinder; Bonnici, Heidi M; Teki, Sundeep; Agus, Trevor R; Pressnitzer, Daniel; Maguire, Eleanor A; Griffiths, Timothy D

    2014-09-22

    Previous behavioural studies have shown that repeated presentation of a randomly chosen acoustic pattern leads to the unsupervised learning of some of its specific acoustic features. The objective of our study was to determine the neural substrate for the representation of freshly learnt acoustic patterns. Subjects first performed a behavioural task that resulted in the incidental learning of three different noise-like acoustic patterns. During subsequent high-resolution functional magnetic resonance imaging scanning, subjects were then exposed again to these three learnt patterns and to others that had not been learned. Multi-voxel pattern analysis was used to test if the learnt acoustic patterns could be 'decoded' from the patterns of activity in the auditory cortex and medial temporal lobe. We found that activity in planum temporale and the hippocampus reliably distinguished between the learnt acoustic patterns. Our results demonstrate that these structures are involved in the neural representation of specific acoustic patterns after they have been learnt.

  10. 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.

  11. Writing magnetic patterns with surface acoustic waves

    SciTech Connect

    Li, Weiyang; Buford, Benjamin; Jander, Albrecht; Dhagat, Pallavi

    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 μm wide stripes of alternating magnetization and a 3 μm 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.

  12. 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.

  13. Segregation of complex acoustic scenes based on temporal coherence

    PubMed Central

    Teki, Sundeep; Chait, Maria; Kumar, Sukhbinder; Shamma, Shihab; Griffiths, Timothy D

    2013-01-01

    In contrast to the complex acoustic environments we encounter everyday, most studies of auditory segregation have used relatively simple signals. Here, we synthesized a new stimulus to examine the detection of coherent patterns (‘figures’) from overlapping ‘background’ signals. In a series of experiments, we demonstrate that human listeners are remarkably sensitive to the emergence of such figures and can tolerate a variety of spectral and temporal perturbations. This robust behavior is consistent with the existence of automatic auditory segregation mechanisms that are highly sensitive to correlations across frequency and time. The observed behavior cannot be explained purely on the basis of adaptation-based models used to explain the segregation of deterministic narrowband signals. We show that the present results are consistent with the predictions of a model of auditory perceptual organization based on temporal coherence. Our data thus support a role for temporal coherence as an organizational principle underlying auditory segregation. DOI: http://dx.doi.org/10.7554/eLife.00699.001 PMID:23898398

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

    PubMed Central

    Vignal, Clémentine; Kelley, Darcy

    2006-01-01

    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

  15. Discrimination and identification of acoustic transient patterns

    NASA Astrophysics Data System (ADS)

    Ballas, J. A.; Howard, J. H., Jr.

    1981-08-01

    The relation between the discrimination and the identification of acoustic patterns can be addressed psychophysically or cognitively. The psychophysical approach predicts a monotonic relationship between performance on the two tasks. Cognitively, the relationship may depend upon the type of structure encoded from the patterns. Structure based upon similarities in runs could enhance discrimination but degrade identification. Hierarchical structural encoding might enhance both tasks. The relationship was investigated in three dual task experiments. In one experiment, trial and error learning was used whereas in the other two, observation of positive examples was used. All three experiments indicated that discrimination was superior to identification, and that the concurrent identification task improved discrimination performance above what has been obtained in single task discrimination studies. The effects of structure in the two tasks were equivocal but implied that the type of structured encoding is important and may be influenced by the procedure used to acquire the patterns.

  16. 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…

  17. Optimal temporal patterns for dynamical cellular signaling

    NASA Astrophysics Data System (ADS)

    Hasegawa, Yoshihiko

    2016-11-01

    Cells use temporal dynamical patterns to transmit information via signaling pathways. As optimality with respect to the environment plays a fundamental role in biological systems, organisms have evolved optimal ways to transmit information. Here, we use optimal control theory to obtain the dynamical signal patterns for the optimal transmission of information, in terms of efficiency (low energy) and reliability (low uncertainty). Adopting an activation-deactivation decoding network, we reproduce several dynamical patterns found in actual signals, such as steep, gradual, and overshooting dynamics. Notably, when minimizing the energy of the input signal, the optimal signals exhibit overshooting, which is a biphasic pattern with transient and steady phases; this pattern is prevalent in actual dynamical patterns. We also identify conditions in which these three patterns (steep, gradual, and overshooting) confer advantages. Our study shows that cellular signal transduction is governed by the principle of minimizing free energy dissipation and uncertainty; these constraints serve as selective pressures when designing dynamical signaling patterns.

  18. Acoustic and temporal partitioning of cicada assemblages in city and mountain environments.

    PubMed

    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.

  19. 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

  20. Acoustic reflex patterns in amyotrophic lateral sclerosis.

    PubMed

    Canale, Andrea; Albera, Roberto; Lacilla, Michelangelo; Canosa, Antonio; Albera, Andrea; Sacco, Francesca; Chiò, Adriano; Calvo, Andrea

    2017-02-01

    The aim of the study is to investigate acoustic reflex testing in amyotrophic lateral sclerosis patients. Amplitude, latency, and rise time of stapedial reflex were recorded for 500 and 1000 Hz contralateral stimulus. Statistical analysis was performed by the Wilcoxon test and the level of significance was set at 5 %. Fifty-one amyotrophic lateral sclerosis patients and ten sex- and age-matched control subjects were studied. Patients were further divided in two groups: amyotrophic lateral sclerosis-bulbar (38 cases, with bulbar signs at evaluation) and amyotrophic lateral sclerosis-spinal (13 cases, without bulbar signs at evaluation). Stapedial reflex was present in all patients. There was a statistically significant difference in the mean amplitude, latency, and rise time between the amyotrophic lateral sclerosis patients as compared with the controls. Amplitude was lower in both the amyotrophic lateral sclerosis-bulbar and the amyotrophic lateral sclerosis-spinal patients than in the controls (p < 0.05) and rise time was longer in both patient groups compared with the controls (p < 0.05). These results confirm the presence of abnormal acoustic reflex patterns in amyotrophic lateral sclerosis cases with bulbar signs and, moreover, suggesting a possible subclinical involvement of the stapedial motor neuron even in amyotrophic lateral sclerosis-spinal patients. Amplitude and rise time seem to be good sensitive parameters for investigating subclinical bulbar involvement.

  1. Auditory Temporal Pattern Discrimination and Reading Ability

    ERIC Educational Resources Information Center

    McAnally, Ken I.; Castles, Anne; Bannister, Susan

    2004-01-01

    The relation between reading ability and performance on an auditory temporal pattern discrimination task was investigated in children who were either good or delayed readers. The stimuli in the primary task consisted of sequences of tones, alternating between high and low frequencies. The threshold interstimulus interval (ISI) for discrimination…

  2. Discrimination of acoustic communication signals by grasshoppers (Chorthippus biguttulus): temporal resolution, temporal integration, and the impact of intrinsic noise.

    PubMed

    Ronacher, Bernhard; Wohlgemuth, Sandra; Vogel, Astrid; Krahe, Rüdiger

    2008-08-01

    A characteristic feature of hearing systems is their ability to resolve both fast and subtle amplitude modulations of acoustic signals. This applies also to grasshoppers, which for mate identification rely mainly on the characteristic temporal patterns of their communication signals. Usually the signals arriving at a receiver are contaminated by various kinds of noise. In addition to extrinsic noise, intrinsic noise caused by stochastic processes within the nervous system contributes to making signal recognition a difficult task. The authors asked to what degree intrinsic noise affects temporal resolution and, particularly, the discrimination of similar acoustic signals. This study aims at exploring the neuronal basis for sexual selection, which depends on exploiting subtle differences between basically similar signals. Applying a metric, by which the similarities of spike trains can be assessed, the authors investigated how well the communication signals of different individuals of the same species could be discriminated and correctly classified based on the responses of auditory neurons. This spike train metric yields clues to the optimal temporal resolution with which spike trains should be evaluated.

  3. Neural representation of three-dimensional acoustic space in the human temporal lobe

    PubMed Central

    Zhang, Xiaolu; Zhang, Qingtian; Hu, Xiaolin; Zhang, Bo

    2015-01-01

    Sound localization is an important function of the human brain, but the underlying cortical mechanisms remain unclear. In this study, we recorded auditory stimuli in three-dimensional space and then replayed the stimuli through earphones during functional magnetic resonance imaging (fMRI). By employing a machine learning algorithm, we successfully decoded sound location from the blood oxygenation level-dependent signals in the temporal lobe. Analysis of the data revealed that different cortical patterns were evoked by sounds from different locations. Specifically, discrimination of sound location along the abscissa axis evoked robust responses in the left posterior superior temporal gyrus (STG) and right mid-STG, discrimination along the elevation (EL) axis evoked robust responses in the left posterior middle temporal lobe (MTL) and right STG, and discrimination along the ordinate axis evoked robust responses in the left mid-MTL and right mid-STG. These results support a distributed representation of acoustic space in human cortex. PMID:25932011

  4. Pattern-formation under acoustic driving forces

    NASA Astrophysics Data System (ADS)

    Valverde, Jose Manuel

    2015-07-01

    Chemical and metallurgical processes enhanced by high intensity acoustic waves, thermoacoustic engines and refrigerators, fuel rods in nuclear reactors, heat exchanger tubes, offshore and vibrating structures, solar thermal collectors, acoustic levitators, microfluidic devices, cycling, musical acoustics, blood flow through veins/arteries, hearing in the mammalian ear, carbon nanotube loudspeakers, etc. The evolution of a myriad of processes involving the oscillation of viscous fluids in the presence of solid boundaries is up to a certain extent influenced by acoustic streaming. In addition to the sound field, viscous energy dissipation at the fluid-solid boundary causes a time-independent fluid circulation, which can lead to a significant enhancement of heat, mass and momentum transfer at large oscillation amplitudes. A particularly relevant phenomenon that can be notably affected by acoustic streaming is the promotion of sound waves by temperature gradients or viceversa (thermoacoustics), which is at the basis of potentially efficient and environmental friendly engines and refrigerators that have attracted a renewed interest in the last years. In the present manuscript, historical developments and the underlying basic physics behind acoustic streaming and thermoacoustics are reviewed from an unifying perspective.

  5. Spatial and temporal frequency domain laser-ultrasound applied in the direct measurement of dispersion relations of surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Grünsteidl, Clemens; Veres, István A.; Roither, Jürgen; Burgholzer, Peter; Murray, Todd W.; Berer, Thomas

    2013-01-01

    We present a laser-ultrasound measurement technique which combines adjustable spatial and temporal modulation of the excitation laser beam. Our method spreads the intensity of an amplitude modulated continuous wave laser over a micro-scale pattern on the sample surface to excite surface acoustic waves. The excitation pattern consists of parallel, equidistant lines and the waves generated from the individual lines interfere on the sample surface. Measurement is done in the spatial-temporal frequency domain allowing the direct determination of dispersion relations. The technique performs with high signal-to-noise-ratios and low peak power densities on the sample.

  6. Acoustic Tweezing and Patterning of Concentration Fields in Microfluidics

    NASA Astrophysics Data System (ADS)

    Karlsen, Jonas T.; Bruus, Henrik

    2017-03-01

    We demonstrate theoretically that acoustic forces acting on inhomogeneous fluids can be used to pattern and manipulate solute concentration fields into spatiotemporally controllable configurations stabilized against gravity. A theoretical framework describing the dynamics of concentration fields that weakly perturb the fluid density and speed of sound is presented and applied to study manipulation of concentration fields in rectangular-channel acoustic eigenmodes and in Bessel-function acoustic vortices. In the first example, methods to obtain horizontal and vertical multilayer stratification of the concentration field at the end of a flow-through channel are presented. In the second example, we demonstrate acoustic tweezing and spatiotemporal manipulation of a local high-concentration region in a lower-concentration medium, thereby extending the realm of acoustic tweezing to include concentration fields.

  7. 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.

  8. Investigation of acoustic streaming patterns around oscillating sharp edges

    PubMed Central

    Nama, Nitesh; Huang, Po-Hsun; 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. PMID:24903475

  9. 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…

  10. A Pattern Mining Approach for Classifying Multivariate Temporal Data.

    PubMed

    Batal, Iyad; Valizadegan, Hamed; Cooper, Gregory F; Hauskrecht, Milos

    2011-11-12

    We study the problem of learning classification models from complex multivariate temporal data encountered in electronic health record systems. The challenge is to define a good set of features that are able to represent well the temporal aspect of the data. Our method relies on temporal abstractions and temporal pattern mining to extract the classification features. Temporal pattern mining usually returns a large number of temporal patterns, most of which may be irrelevant to the classification task. To address this problem, we present the minimal predictive temporal patterns framework to generate a small set of predictive and non-spurious patterns. We apply our approach to the real-world clinical task of predicting patients who are at risk of developing heparin induced thrombocytopenia. The results demonstrate the benefit of our approach in learning accurate classifiers, which is a key step for developing intelligent clinical monitoring systems.

  11. Temporal Patterns of Behavior from the Scheduling of Psychology Quizzes

    ERIC Educational Resources Information Center

    Jarmolowicz, David P.; Hayashi, Yusuke; St. Peter Pipkin, Claire

    2010-01-01

    Temporal patterns of behavior have been observed in real-life performances such as bill passing in the U.S. Congress, in-class studying, and quiz taking. However, the practical utility of understanding these patterns has not been evaluated. The current study demonstrated the presence of temporal patterns of quiz taking in a university-level…

  12. 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.

  13. Network Analysis Using Spatio-Temporal Patterns

    NASA Astrophysics Data System (ADS)

    Miranda, Gisele H. B.; Machicao, Jeaneth; Bruno, Odemir M.

    2016-08-01

    Different network models have been proposed along the last years inspired by real-world topologies. The characterization of these models implies the understanding of the underlying network phenomena, which accounts structural and dynamic properties. Several mathematical tools can be employed to characterize such properties as Cellular Automata (CA), which can be defined as dynamical systems of discrete nature composed by spatially distributed units governed by deterministic rules. In this paper, we proposed a method based on the modeling of one specific CA over distinct network topologies in order to perform the classification of the network model. The proposed methodology consists in the modeling of a binary totalistic CA over a network. The transition function that governs each CA cell is based on the density of living neighbors. Secondly, the distribution of the Shannon entropy is obtained from the evolved spatio-temporal pattern of the referred CA and used as a network descriptor. The experiments were performed using a dataset composed of four different types of networks: random, small-world, scale-free and geographical. We also used cross-validation for training purposes. We evaluated the accuracy of classification as a function of the initial number of living neighbors, and, also, as a function of a threshold parameter related to the density of living neighbors. The results show high accuracy values in distinguishing among the network models which demonstrates the feasibility of the proposed method.

  14. 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

  15. Tunable nanowire patterning using standing surface acoustic waves.

    PubMed

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

    2013-04-23

    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 s. In this approach, SSAWs were generated by interdigital transducers, 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-shaped 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.

  16. 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.

  17. Spatial, Temporal and Spatio-Temporal Patterns of Maritime Piracy

    PubMed Central

    Marchione, Elio

    2013-01-01

    Objectives: To examine patterns in the timing and location of incidents of maritime piracy to see whether, like many urban crimes, attacks cluster in space and time. Methods: Data for all incidents of maritime piracy worldwide recorded by the National Geospatial Intelligence Agency are analyzed using time-series models and methods originally developed to detect disease contagion. Results: At the macro level, analyses suggest that incidents of pirate attacks are concentrated in five subregions of the earth’s oceans and that the time series for these different subregions differ. At the micro level, analyses suggest that for the last 16 years (or more), pirate attacks appear to cluster in space and time suggesting that patterns are not static but are also not random. Conclusions: Much like other types of crime, pirate attacks cluster in space, and following an attack at one location the risk of others at the same location or nearby is temporarily elevated. The identification of such regularities has implications for the understanding of maritime piracy and for predicting the future locations of attacks. PMID:25076796

  18. Auditory spectro-temporal pattern analysis

    NASA Astrophysics Data System (ADS)

    Hall, Joseph W.

    1992-05-01

    The long-term aim of this project is a better understanding of auditory processes which use across frequency or across-ear temporal envelope difference cues to aid performance. Specific areas of investigation include comodulation masking release (CMR), the masking-level difference (MLD), temporal resolution, and the processing of amplitude and frequency modulation. The goal of the first proposed experiment is to examine the possible relation between CMR and auditory phenomena related to auditory scene analysis; the goal of the second experiment is to examine the possible relation between CMR and the MLD for narrowband noise maskers; the goal of the third experiment is to determine the extent to which across-frequency correlation of temporal envelope may influence gap detection for wideband stimuli; the goal of the fourth experiment is to determine whether masking release can be derived from cues based upon across-frequency coherence of frequency modulation; and the goal of the fifth experiment is to examine a modulation masking phenomenon related to frequency modulation. The tasks will be signal detection in masking noise, temporal gap detection, and the detection of frequency modulation. Testing will be performed in a sound-treated room, using a 3AFC adaptive procedure.

  19. 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…

  20. 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

  1. 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…

  2. Spatio-temporal patterns in simple models of marine systems

    NASA Astrophysics Data System (ADS)

    Feudel, U.; Baurmann, M.; Gross, T.

    2009-04-01

    Spatio-temporal patterns in marine systems are a result of the interaction of population dynamics with physical transport processes. These physical transport processes can be either diffusion processes in marine sediments or in the water column. We study the dynamics of one population of bacteria and its nutrient in in a simplified model of a marine sediments, taking into account that the considered bacteria possess an active as well as an inactive state, where activation is processed by signal molecules. Furthermore the nutrients are transported actively by bioirrigation and passively by diffusion. It is shown that under certain conditions Turing patterns can occur which yield heterogeneous spatial patterns of the species. The influence of bioirrigation on Turing patterns leads to the emergence of ''hot spots``, i.e. localized regions of enhanced bacterial activity. All obtained patterns fit quite well to observed patterns in laboratory experiments. Spatio-temporal patterns appear in a predator-prey model, used to describe plankton dynamics. These patterns appear due to the simultaneous emergence of Turing patterns and oscillations in the species abundance in the neighborhood of a Turing-Hopf bifurcation. We observe a large variety of different patterns where i) stationary heterogeneous patterns (e.g. hot and cold spots) compete with spatio-temporal patterns ii) slowly moving patterns are embedded in an oscillatory background iii) moving fronts and spiral waves appear.

  3. Spectral and temporal resolutions of information-bearing acoustic changes for understanding vocoded sentencesa)

    PubMed Central

    Stilp, Christian E.; Goupell, Matthew J.

    2015-01-01

    Short-time spectral changes in the speech signal are important for understanding noise-vocoded sentences. These information-bearing acoustic changes, measured using cochlea-scaled entropy in cochlear implant simulations [CSECI; Stilp et al. (2013). J. Acoust. Soc. Am. 133(2), EL136–EL141; Stilp (2014). J. Acoust. Soc. Am. 135(3), 1518–1529], may offer better understanding of speech perception by cochlear implant (CI) users. However, perceptual importance of CSECI for normal-hearing listeners was tested at only one spectral resolution and one temporal resolution, limiting generalizability of results to CI users. Here, experiments investigated the importance of these informational changes for understanding noise-vocoded sentences at different spectral resolutions (4–24 spectral channels; Experiment 1), temporal resolutions (4–64 Hz cutoff for low-pass filters that extracted amplitude envelopes; Experiment 2), or when both parameters varied (6–12 channels, 8–32 Hz; Experiment 3). Sentence intelligibility was reduced more by replacing high-CSECI intervals with noise than replacing low-CSECI intervals, but only when sentences had sufficient spectral and/or temporal resolution. High-CSECI intervals were more important for speech understanding as spectral resolution worsened and temporal resolution improved. Trade-offs between CSECI and intermediate spectral and temporal resolutions were minimal. These results suggest that signal processing strategies that emphasize information-bearing acoustic changes in speech may improve speech perception for CI users. PMID:25698018

  4. Spatial and Temporal Variability of Zooplankton Thin Layers: The Effects of Composition and Orientation on Acoustic Detection of Layers

    DTIC Science & Technology

    2007-09-30

    Spatial and Temporal Variability of Zooplankton Thin Layers: The Effects of Composition and Orientation on Acoustic Detection of Layers Carin...physical and biological mechanisms of formation and maintenance of thin layers of zooplankton . Because zooplankton can be strong sound scatterers...acoustic instruments are effective at detecting and describing zooplankton thin layers. Using a combination of instruments (acoustics, image-forming

  5. Spatial and Temporal Variability of Zooplankton Thin Layers: The Effects of Composition and Orientation on Acoustic Detection of Layers

    DTIC Science & Technology

    2006-01-01

    Spatial and Temporal Variability of Zooplankton Thin Layers: The Effects of Composition and Orientation on Acoustic Detection of Layers Carin...physical and biological mechanisms of formation and maintenance of thin layers of zooplankton . Because zooplankton can be strong sound scatterers...acoustic instruments are effective at detecting and describing zooplankton thin layers. Using a combination of instruments (acoustics, image-forming

  6. Analysis of brain patterns using temporal measures

    DOEpatents

    Georgopoulos, Apostolos

    2015-08-11

    A set of brain data representing a time series of neurophysiologic activity acquired by spatially distributed sensors arranged to detect neural signaling of a brain (such as by the use of magnetoencephalography) is obtained. The set of brain data is processed to obtain a dynamic brain model based on a set of statistically-independent temporal measures, such as partial cross correlations, among groupings of different time series within the set of brain data. The dynamic brain model represents interactions between neural populations of the brain occurring close in time, such as with zero lag, for example. The dynamic brain model can be analyzed to obtain the neurophysiologic assessment of the brain. Data processing techniques may be used to assess structural or neurochemical brain pathologies.

  7. Complex temporal and spatial patterns in nonequilibrium systems

    SciTech Connect

    Swinney, H.L.

    1991-09-01

    Dynamical systems methods are being developed and used to characterize the formation and evolution of temporal and spatial patterns in systems maintained far from equilibrium. In particular, experiments and analyses are considering electrodeposition of fractal metallic clusters, pattern formation in reaction-diffusion systems, and the primary instabilities of some fluid flows. Novel reactors have been developed to search for chemical patterns (spatial variations in the chemical composition), and sustained patterns have been found in several different one- and two-dimensional geometries. Bifurcations in these patterns are studied by varying control parameters, e.g., the concentrations of the feed chemicals or the temperature. The observed two-dimensional chemical patterns range from the stationary patterns, similar to those predicted by Turing in 1952 but not observed until 1990, to chemical turbulence, which is characterized by large numbers of defects and a rapid decay of spatial correlations. These provide general insights into the formation of spatiotemporal patterns in nonequilibrium systems.

  8. Compensation for acoustic heterogeneities in photoacoustic computed tomography using a variable temporal data truncation reconstruction method

    NASA Astrophysics Data System (ADS)

    Poudel, Joemini; Matthews, Thomas P.; Anastasio, Mark A.; Wang, Lihong V.

    2016-03-01

    Photoacoustic computed tomography (PACT) is an emerging computed imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the absorbed optical energy density within tissue. If the object possesses spatially variant acoustic properties that are unaccounted for by the reconstruction algorithm, the estimated image can contain distortions. While reconstruction algorithms have recently been developed for compensating for this effect, they generally require the objects acoustic properties to be known a priori. To circumvent the need for detailed information regarding an objects acoustic properties, we have previously proposed a half-time reconstruction method for PACT. A half-time reconstruction method estimates the PACT image from a data set that has been temporally truncated to exclude the data components that have been strongly aberrated. In this approach, the degree of temporal truncation is the same for all measurements. However, this strategy can be improved upon it when the approximate sizes and locations of strongly heterogeneous structures such as gas voids or bones are known. In this work, we investigate PACT reconstruction algorithms that are based on a variable temporal data truncation (VTDT) approach that represents a generalization of the half-time reconstruction approach. In the VTDT approach, the degree of temporal truncation for each measurement is determined by the distance between the corresponding transducer location and the nearest known bone or gas void location. Reconstructed images from a numerical phantom is employed to demonstrate the feasibility and effectiveness of the approach.

  9. 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.

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

    PubMed

    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.

  11. 1988 Wet deposition temporal and spatial patterns in North America

    SciTech Connect

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

    1992-03-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1988 and spatial patterns for 1988. It is the third in a series of reports that investigate 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. 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 1988 annual, winter, and summer periods. Temporal pattern analyses use a subset of 35 sites over a 10-year (1979--1988) period and an expanded subset of 137 sites, with greater spatial coverage, over a 7-year (1982--1988) period. The 10-year period represents the longest period with wet deposition monitoring data available that has a sufficient number of sites with data of known quality to allow a descriptive summary of annual temporal patterns. Sen's median trend estimate and Kendall's seasonal tau (KST) test are calculated for each ion species concentration and deposition at each site in both subsets.

  12. 1988 Wet deposition temporal and spatial patterns in North America

    SciTech Connect

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

    1992-03-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1988 and spatial patterns for 1988. It is the third in a series of reports that investigate 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. 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 1988 annual, winter, and summer periods. Temporal pattern analyses use a subset of 35 sites over a 10-year (1979--1988) period and an expanded subset of 137 sites, with greater spatial coverage, over a 7-year (1982--1988) period. The 10-year period represents the longest period with wet deposition monitoring data available that has a sufficient number of sites with data of known quality to allow a descriptive summary of annual temporal patterns. Sen`s median trend estimate and Kendall`s seasonal tau (KST) test are calculated for each ion species concentration and deposition at each site in both subsets.

  13. A New Surgical Approach for Direct Acoustic Cochlear Implant: A Temporal Bone Study

    PubMed Central

    Bruschini, Luca; Forli, Francesca; Vito, Andrea De; Berrettini, Stefano

    2016-01-01

    Objectives The direct acoustic cochlear implant (DACI) is among the latest developments in the field of implantable acoustic prostheses. The surgical procedure requires a mastoidectomy and a posterior-inferior tympanotomy, with access to the facial recess at the level of the oval window, in a complex and lengthy surgical approach. Here, we report a new and considerably shorter surgical approach. Methods The new approach involves positioning of artificial incus above the oval window through the superior-anterior tympanotomy. We performed DACI placement in temporal bone specimens (n=5) to assess the feasibility of the new approach. Results The average time for the DACI implant in the temporal bones was only 112 minutes (range, 94 to 142 minutes) and there was little clinical risk associated with the procedure. Access was easy and drilling was minimal. Conclusion Our approach simplified the surgical procedure and consequently reduced the time required for DACI placement. PMID:27334513

  14. 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.

  15. Spatiotemporal patterns of acoustic emission (AE) activity in salt mine

    NASA Astrophysics Data System (ADS)

    Maghsoudi, S.; Cesca, S.; Hainzl, S.; Kaiser, D.; Dahm, T.

    2012-04-01

    Assessing the magnitude of completeness (Mc) is essential for the correct interpretation of earthquake catalogs. Knowledge on the spatiotemporal variation of Mc allows the mapping of other seismicity parameters, such as b-values. Spatial and temporal variations of b-values can indicate structural heterogeneities, stress perturbations and time-dependent fracturing processes. In order to precisely estimate Mc in strongly heterogeneous media, we propose a 3D development of the probabilistic magnitude of completeness (PMC) method, which relies on the analysis of network detection capabilities, to study spatial distribution of the Mc and b-value estimations for mining networks. We used a large dataset including more than 1 million acoustic emissions (AE), recorded at the Morsleben salt mine, Germany. Our study shows that the PMC estimations strongly depend on the source-receiver direction, and cannot be correctly accounted using a standard approach. The comparison between Mc using the 3D PMC method and Gutenberg-Richter methods show agreements for two reference depth ranges. Following our approach, we estimate Mc ranging between 1.25 (AE ,relative acoustic magnitude), at the center of the network, and 3.5, at further distances outside the network. Our method provides small-scale details about the capability of sensors to detect an AE event, and spatial distributions of Mc and b-value, which can be linked to the presence of structural heterogeneities or cavities in specific directions. Effects of heterogeneities on detection analysis are confirmed by synthetic tests using waveform modeling in heterogeneous media. This work has been funded by the German BMBF "Geotechnologien" project MINE (BMBF03G0737A).

  16. 1986 wet deposition temporal and spatial patterns in North America

    SciTech Connect

    Olsen, A.R.

    1989-07-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1986 and spatial patterns for 1986. The report provides statistical distribution summaries of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. The data in the report are from the Acid Depositing System (ADS) for the statistical reporting of North American deposition data. Isopleth maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1986 annual, winter, and summer periods. The temporal pattern analyses use a subset of 30 sites over an 8-year (1979-1986) period and an expanded subset of 137 sites with greater spatial coverage over a 5-year (1982-1986) period. The 8-year period represents the longest period with wet deposition monitoring data unavailable that has a sufficient number of sites with data of known quality to allow a descriptive summary of annual temporal patterns. 19 refs., 105 figs., 29 tabs.

  17. Temporal coherence of the acoustic field forward propagated through a continental shelf with random internal waves.

    PubMed

    Gong, Zheng; Chen, Tianrun; Ratilal, Purnima; Makris, Nicholas C

    2013-11-01

    An analytical model derived from normal mode theory for the accumulated effects of range-dependent multiple forward scattering is applied to estimate the temporal coherence of the acoustic field forward propagated through a continental-shelf waveguide containing random three-dimensional internal waves. The modeled coherence time scale of narrow band low-frequency acoustic field fluctuations after propagating through a continental-shelf waveguide is shown to decay with a power-law of range to the -1/2 beyond roughly 1 km, decrease with increasing internal wave energy, to be consistent with measured acoustic coherence time scales. The model should provide a useful prediction of the acoustic coherence time scale as a function of internal wave energy in continental-shelf environments. The acoustic coherence time scale is an important parameter in remote sensing applications because it determines (i) the time window within which standard coherent processing such as matched filtering may be conducted, and (ii) the number of statistically independent fluctuations in a given measurement period that determines the variance reduction possible by stationary averaging.

  18. Impaired extraction of speech rhythm from temporal modulation patterns in speech in developmental dyslexia

    PubMed Central

    Leong, Victoria; Goswami, Usha

    2014-01-01

    Dyslexia is associated with impaired neural representation of the sound structure of words (phonology). The “phonological deficit” in dyslexia may arise in part from impaired speech rhythm perception, thought to depend on neural oscillatory phase-locking to slow amplitude modulation (AM) patterns in the speech envelope. Speech contains AM patterns at multiple temporal rates, and these different AM rates are associated with phonological units of different grain sizes, e.g., related to stress, syllables or phonemes. Here, we assess the ability of adults with dyslexia to use speech AMs to identify rhythm patterns (RPs). We study 3 important temporal rates: “Stress” (~2 Hz), “Syllable” (~4 Hz) and “Sub-beat” (reduced syllables, ~14 Hz). 21 dyslexics and 21 controls listened to nursery rhyme sentences that had been tone-vocoded using either single AM rates from the speech envelope (Stress only, Syllable only, Sub-beat only) or pairs of AM rates (Stress + Syllable, Syllable + Sub-beat). They were asked to use the acoustic rhythm of the stimulus to identity the original nursery rhyme sentence. The data showed that dyslexics were significantly poorer at detecting rhythm compared to controls when they had to utilize multi-rate temporal information from pairs of AMs (Stress + Syllable or Syllable + Sub-beat). These data suggest that dyslexia is associated with a reduced ability to utilize AMs <20 Hz for rhythm recognition. This perceptual deficit in utilizing AM patterns in speech could be underpinned by less efficient neuronal phase alignment and cross-frequency neuronal oscillatory synchronization in dyslexia. Dyslexics' perceptual difficulties in capturing the full spectro-temporal complexity of speech over multiple timescales could contribute to the development of impaired phonological representations for words, the cognitive hallmark of dyslexia across languages. PMID:24605099

  19. Acoustic droplet–hydrogel composites for spatial and temporal control of growth factor delivery and scaffold stiffness

    PubMed Central

    Fabiilli, Mario L.; Wilson, Christopher G.; Padilla, Frédéric; Martín-Saavedra, Francisco M.; Fowlkes, J. Brian; Franceschi, Renny T.

    2013-01-01

    Wound healing is regulated by temporally and spatially restricted patterns of growth factor signaling, but there are few delivery vehicles capable of the “on-demand” release necessary for recapitulating these patterns. Recently we described a perfluorocarbon double emulsion that selectively releases a protein payload upon exposure to ultrasound through a process known as acoustic droplet vaporization (ADV). In this study, we describe a delivery system composed of fibrin hydrogels doped with growth factor-loaded double emulsion for applications in tissue regeneration. Release of immunoreactive basic fibroblast growth factor (bFGF) from the composites increased up to 5-fold following ADV and delayed release was achieved by delaying exposure to ultrasound. Releasates of ultrasound-treated materials significantly increased the proliferation of endothelial cells compared to sham controls, indicating that the released bFGF was bioactive. ADV also triggered changes in the ultrastructure and mechanical properties of the fibrin as bubble formation and consolidation of the fibrin in ultrasound-treated composites were accompanied by up to a 22-fold increase in shear stiffness. ADV did not reduce the viability of cells suspended in composite scaffolds. These results demonstrate that an acoustic droplet–hydrogel composite could have broad utility in promoting wound healing through on-demand control of growth factor release and/or scaffold architecture. PMID:23535233

  20. 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.

  1. Mastoidectomy dimensions for direct acoustic cochlear implantation: a human cadaveric temporal bone study.

    PubMed

    Fiorino, Francesco; Amadori, Maurizio

    2017-02-28

    The objective of the present paper was to acquire information about the mastoidectomy size necessary to obtain an optimal placement of the direct acoustic cochlear implant actuator and fixation system. Ten human cadaveric temporal bones were dissected and implanted with direct acoustic cochlear implant. Mastoidectomy size was determined after implantation in each temporal bone. A bone bed for the receiver/stimulator, mastoidectomy and a large posterior tympanotomy were drilled out. The mastoidectomy was progressively enlarged posteriorly in small steps until the actuator template was judged adequately oriented to enable passage of the rod through the posterior tympanotomy without any contact with the bony walls. The distance between different landmarks in the mastoidectomy was measured. All measured values showed a high degree of consistency, with limited median absolute deviation values. One of the most critical measure, i.e. the distance between the posterior margin of the mastoidectomy to the superior rim of the bony external ear canal wall, ranged from 13 to 16 mm with a median value of 15 mm. Prior knowledge of the ideal size of the mastoidectomy for direct acoustic cochlear implant facilitates the positioning of the fixation system and may save time during implant surgery.

  2. Real-time decomposition and recognition of acoustical patterns with an analog neural computer

    NASA Astrophysics Data System (ADS)

    Mueller, Paul; Van der Spiegel, Jan; Blackman, David; Donham, Christopher; Cummings, Ralph

    1992-09-01

    A prototype programmable analog neural computer has been assembled from over 100 custom VLSI modules containing neurons, synapses, routing switches, and programmable synaptic time constants. The modules are directly interconnected and arbitrary network configurations can be programmed. Connection symmetry and modular construction allow expansion of the network to any size. The network runs in real time analog mode, but connection architecture as well as neuron and synapse parameters are controlled by a digital host. Network performance is monitored by the host through an A/D interface and used in the implementation of learning algorithms. The machine is intended for real time, real world computations. In its current configuration maximal speed is equivalent to that of a digital machine capable of 1011 FLOPS. The programmable synaptic time constants permit the real time computation of temporal patterns as they occur in speech and other acoustic signals. Several applications involving the dynamic decomposition and recognition of acoustical patterns including speech signals (phonemes) are described. The decomposition network is loosely based on the primary auditory system of higher vertebrates. It extracts and represents by the activity in different neuron arrays the following pattern primitives: frequency, bandwidth, amplitude, amplitude modulation, amplitude modulation frequency, frequency modulation, frequency modulation frequency, duration, sequence. The frequency tuned units are the first stage and form the input space for subsequent stages that extract the other primitives, e.g., bandwidth, amplitude modulation, etc., for different frequency bands. Acoustic input generates highly specific, relatively sparse distributed activity in this feature space, which is decoded and recognized by units trained by specific input patterns such as phonemes or diphones or active sonar patterns. Through simple feedback connections in conjunction with synaptic time constants the

  3. Temporal acoustic measures distinguish primary progressive apraxia of speech from primary progressive aphasia.

    PubMed

    Duffy, Joseph R; Hanley, Holly; Utianski, Rene; Clark, Heather; Strand, Edythe; Josephs, Keith A; Whitwell, Jennifer L

    2017-02-07

    The purpose of this study was to determine if acoustic measures of duration and syllable rate during word and sentence repetition, and a measure of within-word lexical stress, distinguish speakers with primary progressive apraxia of speech (PPAOS) from nonapraxic speakers with the agrammatic or logopenic variants of primary progressive aphasia (PPA), and control speakers. Results revealed that the PPAOS group had longer durations and reduced rate of syllable production for most words and sentences, and the measure of lexical stress. Sensitivity and specificity indices for the PPAOS versus the other groups were highest for longer multisyllabic words and sentences. For the PPAOS group, correlations between acoustic measures and perceptual ratings of AOS were moderately high to high. Several temporal measures used in this study may aid differential diagnosis and help quantify features of PPAOS that are distinct from those associated with PPA in which AOS is not present.

  4. Planktivorous Fish Recognize Temporal Motion Patterns of Suspended Particles

    NASA Astrophysics Data System (ADS)

    Strickler, J. R.; Tsonis, A.

    2004-12-01

    Small planktivorous fish feed by selective captures of individual zooplankters. We realize that: 1) the predator, as well as the prey is suspended in the water column, which does not provide either with stable reference points; 2) the ambient flow field acts differently on the larger predators than on the much smaller prey; and 3) within the water column there are many suspended particles of lower nutritional value than the zooplankters represent. We investigated in the laboratory whether or not fish can distinguish between small targets moving with different swimming patterns, e.g. particles entrained passively in the ambient water flow versus entrained but actively swimming particles. We created in an aquarium computer-animated stimuli with motion patterns ranging from random to actual swimming motions of live animals. The results show that planktivorous fish can recognize temporal patterns in a visually homogeneous environment. Therefore, blue-water fish must process visual information similar to terrestrial animals processing auditory information.

  5. 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.

  6. Temporal patterns in rates of community change during succession.

    PubMed

    Anderson, Kristina J

    2007-06-01

    While ecological dogma holds that rates of community change decrease over the course of succession, this idea has yet to be tested systematically across a wide variety of successional sequences. Here, I review and define several measures of community change rates for species presence-absence data and test for temporal patterns therein using data acquired from 16 studies comprising 62 successional sequences. Community types include plant secondary and primary succession as well as succession of arthropods on defaunated mangrove islands and carcasses. Rates of species gain generally decline through time, whereas rates of species loss display no systematic temporal trends. As a result, percent community turnover generally declines while species richness increases--both in a decelerating manner. Although communities with relatively minor abiotic and dispersal limitations (e.g., plant secondary successional communities) exhibit rapidly declining rates of change, limitations arising from harsh abiotic conditions or spatial isolation of the community appear to substantially alter temporal patterns in rates of successional change.

  7. Exploring Temporal Patterns of Stress in Adolescent Girls with Headache.

    PubMed

    Björling, Elin A; Singh, Narayan

    2017-02-01

    As part of a larger study on perceived stress and headaches in 2009, momentary perceived stress, head pain levels and stress-related symptom data were collected. This paper explores a temporal analysis of the patterns of stress, as well as an analysis of momentary and retrospective stress-related symptoms compared by level of headache activity. Adolescent girls (N = 31) ages 14-18 were randomly cued by electronic diaries 7 times per day over a 21-day period responding to momentary questions about level of head pain, perceived stress and stress-related symptoms. Multivariate general linear modelling was used to determine significant differences among headache groups in relation to temporal patterns of stress. Significant headache group differences were found on retrospective and momentary stress-related symptom measures. A total of 2841 diary responses captured stress levels, head pain and related symptoms. The chronic headache (CH) group reported the highest levels of hourly and daily stress, followed by the moderate headache (MH) and low headache (LH) groups. Patterns of stress for the three headache groups were statistically distinct, illustrating increased stress in girls with more frequent head pain. This evidence suggests that because of increased stress, girls with recurrent head pain are likely a vulnerable population who may benefit from stress-reducing interventions. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Recurrent Coupling Improves Discrimination of Temporal Spike Patterns

    PubMed Central

    Yuan, Chun-Wei; Leibold, Christian

    2012-01-01

    Despite the ubiquitous presence of recurrent synaptic connections in sensory neuronal systems, their general functional purpose is not well understood. A recent conceptual advance has been achieved by theories of reservoir computing in which recurrent networks have been proposed to generate short-term memory as well as to improve neuronal representation of the sensory input for subsequent computations. Here, we present a numerical study on the distinct effects of inhibitory and excitatory recurrence in a canonical linear classification task. It is found that both types of coupling improve the ability to discriminate temporal spike patterns as compared to a purely feed-forward system, although in different ways. For a large class of inhibitory networks, the network’s performance is optimal as long as a fraction of roughly 50% of neurons per stimulus is active in the resulting population code. Thereby the contribution of inactive neurons to the neural code is found to be even more informative than that of the active neurons, generating an inherent robustness of classification performance against temporal jitter of the input spikes. Excitatory couplings are found to not only produce a short-term memory buffer but also to improve linear separability of the population patterns by evoking more irregular firing as compared to the purely inhibitory case. As the excitatory connectivity becomes more sparse, firing becomes more variable, and pattern separability improves. We argue that the proposed paradigm is particularly well-suited as a conceptual framework for processing of sensory information in the auditory pathway. PMID:22586392

  9. Inverse hydrological modelling of spatio-temporal rainfall patterns

    NASA Astrophysics Data System (ADS)

    Grundmann, Jens; Hörning, Sebastian; Bárdossy, András

    2016-04-01

    Distributed hydrological models are commonly used for simulating the non-linear response of a watershed to rainfall events for addressing different hydrological properties of the landscape. Such models are driven by spatial rainfall patterns for consecutive time steps, which are normally generated from point measurements using spatial interpolation methods. However, such methods fail in reproducing the true spatio-temporal rainfall patterns especially in data scarce regions with poorly gauged catchments or for highly dynamic, small scaled rainstorms which are not well recorded by existing monitoring networks. Consequently, uncertainties are associated with poorly identified spatio-temporal rainfall distribution in distributed rainfall-runoff-modelling since the amount of rainfall received by a catchment as well as the dynamics of the runoff generation of flood waves are underestimated. For addressing these challenges a novel methodology for inverse hydrological modelling is proposed using a Markov-Chain-Monte-Carlo framework. Thereby, potential candidates of spatio-temporal rainfall patterns are generated and selected according their ability to reproduce the observed surface runoff at the catchment outlet for a given transfer function in a best way. The Methodology combines the concept of random mixing of random spatial fields with a grid-based spatial distributed rainfall runoff model. The conditional target rainfall field is obtained as a linear combination of unconditional spatial random fields. The corresponding weights of the linear combination are selected such that the spatial variability of the rainfall amounts as well as the actual observed rainfall values are reproduced. The functionality of the methodology is demonstrated on a synthetic example. Thereby, the known spatio-temporal distribution of rainfall is reproduced for a given number of point observations of rainfall and the integral catchment response at the catchment outlet for a synthetic catchment

  10. Detecting spatial and temporal dot patterns in noise

    NASA Astrophysics Data System (ADS)

    Drum, Bruce

    1991-06-01

    The visual system can be thought of as an image processor that first reduces the dynamic retinal image to a temporal succession of noisy but redundant arrays of retinal ganglion cell signals and then reconstructs from these signals a stable representation of the external world. The process by which this reconstruction takes place is still poorly understood. An obvious requirement, however, is the capability to reject the noise in the individual neural signals. I am investigating the visual system's noise rejection capabilities by determining how much noise must be added to dot patterns to reduce them to detection threshold. The stimuli are patches of nonrandom dots surrounded by dynamic random dots of the same mean luminance and contrast. The non randomness, or coherence, of the stimulus patterns is controlled by randomizing a known percentage of stimulus dots in each frame of the dynamic display. The stimulus patterns can be limited to either spatial or temporal information. In addition to coherence, the size, duration and retinal location of the stimulus can be varied, as well as the temporal frequency, dot size, contrast and mean luminance of the entire display. Coherence thresholds are generally elevated by any operation that reduced the number of ganglion cells responding to the stimulus, either by reducing the stimulus area or duration or by limiting the response to a subset of ganglion cells (e.g., the receptive field overlap or response redundancy factor can be reduced by preferentially stimulating only one functional ganglion cell type, or by testing glaucoma patients with partially destroyed ganglion cell layers). The visual system thus appears to reduce noise effects by integrating neural responses that are correlated in either space or time.

  11. Reconstructing spatial and temporal patterns of paleoglaciation across Central Asia

    NASA Astrophysics Data System (ADS)

    Stroeven, Arjen P.

    2014-05-01

    Understanding the behaviour of mountain glaciers and ice caps, the evolution of mountain landscapes, and testing global climate models all require well-constrained information on past spatial and temporal patterns of glacier change. Particularly important are transitional regions that have high spatial and temporal variation in glacier activity and that can provide a sensitive record of past climate change. Central Asia is an extreme continental location with glaciers that have responded sensitively to variations in major regional climate systems. As an international team, we are reconstructing glacial histories of several areas of the Tibetan Plateau as well as along the Tian Shan, Altai and Kunlun Mountains. Building on previous work, we are using remote sensing-based geomorphological mapping augmented with field observations to map out glacial landforms and the maximum distributions of erratics. We then use cosmogenic nuclide Be-10 and Al-26, optically stimulated luminescence, and electron spin resonance dating of moraines and other landforms to compare dating techniques and to constrain the ages of defined extents of paleo-glaciers and ice caps. Comparing consistently dated glacial histories across central Asia provides an opportunity to examine shifts in the dominance patterns of climate systems over time in the region. 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 then. Initial numerical modelling attempting to simulate mapped and dated paleoglacial extents indicates that relatively limited cooling is sufficient to produce observed past expansions of glaciers across the Tibetan Plateau, and predicts complex basal thermal regimes in some locations that

  12. Temporal and acoustic characteristics of Greek vowels produced by adults with cerebral palsy

    NASA Astrophysics Data System (ADS)

    Botinis, Antonis; Orfanidou, Ioanna; Fourakis, Marios; Fourakis, Marios

    2005-09-01

    The present investigation examined the temporal and spectral characteristics of Greek vowels as produced by speakers with intact (NO) versus cerebral palsy affected (CP) neuromuscular systems. Six NO and six CP native speakers of Greek produced the Greek vowels [i, e, a, o, u] in the first syllable of CVCV nonsense words in a short carrier phrase. Stress could be on either the first or second syllable. There were three female and three male speakers in each group. In terms of temporal characteristics, the results showed that: vowels produced by CP speakers were longer than vowels produced by NO speakers; stressed vowels were longer than unstressed vowels; vowels produced by female speakers were longer than vowels produced by male speakers. In terms of spectral characteristics the results showed that the vowel space of the CP speakers was smaller than that of the NO speakers. This is similar to the results recently reported by Liu et al. [J. Acoust. Soc. Am. 117, 3879-3889 (2005)] for CP speakers of Mandarin. There was also a reduction of the acoustic vowel space defined by unstressed vowels, but this reduction was much more pronounced in the vowel productions of CP speakers than NO speakers.

  13. Acoustic temporal modulation detection and speech perception in cochlear implant listeners.

    PubMed

    Won, Jong Ho; Drennan, Ward R; Nie, Kaibao; Jameyson, Elyse M; Rubinstein, Jay T

    2011-07-01

    The goals of the present study were to measure acoustic temporal modulation transfer functions (TMTFs) in cochlear implant listeners and examine the relationship between modulation detection and speech recognition abilities. The effects of automatic gain control, presentation level and number of channels on modulation detection thresholds (MDTs) were examined using the listeners' clinical sound processor. The general form of the TMTF was low-pass, consistent with previous studies. The operation of automatic gain control had no effect on MDTs when the stimuli were presented at 65 dBA. MDTs were not dependent on the presentation levels (ranging from 50 to 75 dBA) nor on the number of channels. Significant correlations were found between MDTs and speech recognition scores. The rates of decay of the TMTFs were predictive of speech recognition abilities. Spectral-ripple discrimination was evaluated to examine the relationship between temporal and spectral envelope sensitivities. No correlations were found between the two measures, and 56% of the variance in speech recognition was predicted jointly by the two tasks. The present study suggests that temporal modulation detection measured with the sound processor can serve as a useful measure of the ability of clinical sound processing strategies to deliver clinically pertinent temporal information.

  14. Temporal Patterns of Road Traffic Injuries in Iran

    PubMed Central

    Khorshidi, Ali; Ainy, Elaheh; Hashemi Nazari, Seyed Saeed; Soori, Hamid

    2016-01-01

    Background Road traffic injuries (RTIs) are the main causes of death and disability in Iran. However, very few studies about the temporal variations of RTIs have been published to date. Objectives This study was conducted to investigate the temporal pattern of RTIs in Iran in 2012. Materials and Methods All road traffic accidents (RTAs) reported to traffic police during a one-year period (March 21, 2012 through March 21, 2013) were investigated after obtaining permission from the law enforcement force of the Islamic Republic of Iran. Distributions of RTAs were obtained for season, month, week, and hour scales, and for long holidays (more than one day) and the day prior to long holidays (DPLH). The final analysis was carried out using the Poisson regression model to calculate incidence rate ratios for RTIs. All analyses were conducted using STATA 13.1 and Excel software; statistical significance was set at P < 0.05. Results A total of 452,192 RTAs were examined. The estimated rate of all accidents was 219 per 10,000 registered vehicles, or 595 per 100,000 people. About 28% of all RTAs, and more than one third of fatal RTAs, occurred during the summer months. The incidence rate for all traffic accidents on DPLH was 1.20, compared to workdays as a reference category, and it was 1.40 for fatal crashes. The rate of fatal road traffic accidents in outer cities was 3.2 times higher than in inner ones. Conclusions Our findings reveal that there are temporal variations in traffic accidents, and long holidays significantly influence accident rates. Traffic injuries have different patterns on outer/inner city roads, based on weekday and holiday status. Thus, these findings could be used to create effective initiatives aimed at traffic management. PMID:27703958

  15. Temporally-patterned magnetic fields induce complete fragmentation in planaria.

    PubMed

    Murugan, Nirosha J; Karbowski, Lukasz M; Lafrenie, Robert M; Persinger, Michael A

    2013-01-01

    A tandem sequence composed of weak temporally-patterned magnetic fields was discovered that produced 100% dissolution of planarian in their home environment. After five consecutive days of 6.5 hr exposure to a frequency-modulated magnetic field (0.1 to 2 µT), immediately followed by an additional 6.5 hr exposure on the fifth day, to another complex field (0.5 to 5 µT) with exponentially increasing spectral power 100% of planarian dissolved within 24 hr. Reversal of the sequence of the fields or presentation of only one pattern for the same duration did not produce this effect. Direct video evidence showed expansion (by visual estimation ∼twice normal volume) of the planarian following the first field pattern followed by size reduction (estimated ∼1/2 of normal volume) and death upon activation of the second pattern. The contortions displayed by the planarian during the last field exposure suggest effects on contractile proteins and alterations in the cell membrane's permeability to water.

  16. Pattern-level temporal difference learning, data fusion, and chess

    NASA Astrophysics Data System (ADS)

    Levinson, Robert; Weber, Ryan J.

    2000-04-01

    Our research group is using chess as a vehicle for studying the fusion of adaptation, multiple representation, and search technologies for real-time decision making. Chess systems like Deep Blue have achieved Grandmaster chess play with a brute-force search of the game tree and human- supplied information, like piece-values and opening books. However, subtle aspects of chess, including positional features and advanced concepts, are not capable of being represented or processed efficiently with the standard method. Since 1989, Morph I-III have exhibited more autonomy and learning ability than traditional chess programs in `adaptive pattern-oriented chess'. Like its predecessors, Morph IV is a reinforcement learner, but it also uses a new technique we call pattern-level TD and Q-learning to mathematically map the state space and effectively learn to classify situations. Its three knowledge sources include two traditional ones: material and a piece-square table, and a new method called Distance. These are combined using a simple genetic algorithm and a decision tree. This paper shows the effectiveness of fusing knowledge to replace search in real-time situations, since an agent which combines all sources is capable of consistently beating an agent which employs any of the individual knowledge sources. Surprisingly, the pattern-level TD agent is slightly superior to the pattern-level Q-learning agent, despite the fact that the Q-learning agent updates more Q-values on each temporal step.

  17. Acoustic sleepiness detection: framework and validation of a speech-adapted pattern recognition approach.

    PubMed

    Krajewski, Jarek; Batliner, Anton; Golz, Martin

    2009-08-01

    This article describes a general framework for detecting sleepiness states on the basis of prosody, articulation, and speech-quality-related speech characteristics. The advantages of this automatic real-time approach are that obtaining speech data is nonobstrusive and is free from sensor application and calibration efforts. Different types of acoustic features derived from speech, speaker, and emotion recognition were employed (frame-level-based speech features). Combing these features with high-level contour descriptors, which capture the temporal information of frame-level descriptor contours, results in 45,088 features per speech sample. In general, the measurement process follows the speech-adapted steps of pattern recognition: (1) recording speech, (2) preprocessing, (3) feature computation (using perceptual and signal-processing-related features such as, e.g., fundamental frequency, intensity, pause patterns, formants, and cepstral coefficients), (4) dimensionality reduction, (5) classification, and (6) evaluation. After a correlation-filter-based feature subset selection employed on the feature space in order to find most relevant features, different classification models were trained. The best model-namely, the support-vector machine-achieved 86.1% classification accuracy in predicting sleepiness in a sleep deprivation study (two-class problem, N=12; 01.00-08.00 a.m.).

  18. 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

  19. Spatial and temporal patterns of eastern Australia subtropical coral communities.

    PubMed

    Dalton, Steven J; Roff, George

    2013-01-01

    Despite increases in the frequency and intensity of disturbances on coral reefs over the past few decades, the response of subtropical coral assemblages to climate change is poorly understood. To address this knowledge gap on Australian reefs and provide a baseline for future comparisons, we quantified spatial (10-100's of kilometres) and temporal (decadal) patterns of benthic assemblages across a latitudinal gradient along the east Australian coastline (23.5° S to 31.5° S). Benthic community composition was quantified at six locations from the southern Great Barrier Reef, Queensland (Heron Reef, 23.5° S, 152° E) to northern New South Wales (31° S, 153.1° E) and at Lord Howe Island (31.5° S, 159.1° E). Our results indicate significant latitudinal differences in benthic assemblages, while community composition at some sites was more similar to those hundreds of kilometres away than to that of neighbouring reefs. A general trend was observed with decreasing cover of Acroporidae with increasing latitude, corresponding with an increasing cover of Pocilloporidae and Dendrophylliidae. Heron Reef comprised a high proportion of Acropora corals (43% total coral cover) and coralline algae (44%). In contrast, high-latitude reefs were dominated by mixed coral assemblages (0-52%) and high macroalgal cover (16-27%). Decadal comparisons of high-latitude reefs showed regional stability of benthic assemblages (9 out of 11 assemblages remained stable at > 75% similarity), during a period of warming oceans (0.15-0.24°C per decade). Such temporal stability suggests that eastern Australian subtropical communities may be more resistant than tropical reef communities that have experienced assembly shifts caused by perturbations associated with recent global climate change. Despite the clear differences in the structure of coral assemblages evident in our spatial surveys, we suggest that the temporal stability of high-latitude reefs may provide a limited refuge for tropical coral

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

    USGS Publications Warehouse

    Kovach, Ryan P.; Ellison, Stephen; Pyare, Sanjay; Tallmon, David

    2015-01-01

    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

  1. 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.

  2. Target and temporal pattern selection at neocortical synapses.

    PubMed Central

    Thomson, Alex M; Bannister, A Peter; Mercer, Audrey; Morris, Oliver T

    2002-01-01

    We attempt to summarize the properties of cortical synaptic connections and the precision with which they select their targets in the context of information processing in cortical circuits. High-frequency presynaptic bursts result in rapidly depressing responses at most inputs onto spiny cells and onto some interneurons. These 'phasic' connections detect novelty and changes in the firing rate, but report frequency of maintained activity poorly. By contrast, facilitating inputs to interneurons that target dendrites produce little or no response at low frequencies, but a facilitating-augmenting response to maintained firing. The neurons activated, the cells they in turn target and the properties of those synapses determine which parts of the circuit are recruited and in what temporal pattern. Inhibitory interneurons provide both temporal and spatial tuning. The 'forward' flow from layer-4 excitatory neurons to layer 3 and from 3 to 5 activates predominantly pyramids. 'Back' projections, from 3 to 4 and 5 to 3, do not activate excitatory cells, but target interneurons. Despite, therefore, an increasing complexity in the information integrated as it is processed through these layers, there is little 'contamination' by 'back' projections. That layer 6 acts both as a primary input layer feeding excitation 'forward' to excitatory cells in other layers and as a higher-order layer with more integrated response properties feeding inhibition to layer 4 is discussed. PMID:12626012

  3. Uncovering Urban Temporal Patterns from Geo-Tagged Photography

    PubMed Central

    Paldino, Silvia; Kondor, Dániel; Sobolevsky, Stanislav; González, Marta C.; Ratti, Carlo

    2016-01-01

    We live in a world where digital trails of different forms of human activities compose big urban data, allowing us to detect many aspects of how people experience the city in which they live or come to visit. In this study we propose to enhance urban planning by taking into a consideration individual preferences using information from an unconventional big data source: dataset of geo-tagged photographs that people take in cities which we then use as a measure of urban attractiveness. We discover and compare a temporal behavior of residents and visitors in ten most photographed cities in the world. Looking at the periodicity in urban attractiveness, the results show that the strongest periodic patterns for visitors are usually weekly or monthly. Moreover, by dividing cities into two groups based on which continent they belong to (i.e., North America or Europe), it can be concluded that unlike European cities, behavior of visitors in the US cities in general is similar to the behavior of their residents. Finally, we apply two indices, called “dilatation attractiveness index” and “dilatation index”, to our dataset which tell us the spatial and temporal attractiveness pulsations in the city. The proposed methodology is not only important for urban planning, but also does support various business and public stakeholder decision processes, concentrated for example around the question how to attract more visitors to the city or estimate the impact of special events organized there. PMID:27935979

  4. Uncovering Urban Temporal Patterns from Geo-Tagged Photography.

    PubMed

    Paldino, Silvia; Kondor, Dániel; Bojic, Iva; Sobolevsky, Stanislav; González, Marta C; Ratti, Carlo

    2016-01-01

    We live in a world where digital trails of different forms of human activities compose big urban data, allowing us to detect many aspects of how people experience the city in which they live or come to visit. In this study we propose to enhance urban planning by taking into a consideration individual preferences using information from an unconventional big data source: dataset of geo-tagged photographs that people take in cities which we then use as a measure of urban attractiveness. We discover and compare a temporal behavior of residents and visitors in ten most photographed cities in the world. Looking at the periodicity in urban attractiveness, the results show that the strongest periodic patterns for visitors are usually weekly or monthly. Moreover, by dividing cities into two groups based on which continent they belong to (i.e., North America or Europe), it can be concluded that unlike European cities, behavior of visitors in the US cities in general is similar to the behavior of their residents. Finally, we apply two indices, called "dilatation attractiveness index" and "dilatation index", to our dataset which tell us the spatial and temporal attractiveness pulsations in the city. The proposed methodology is not only important for urban planning, but also does support various business and public stakeholder decision processes, concentrated for example around the question how to attract more visitors to the city or estimate the impact of special events organized there.

  5. 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

  6. Complex temporal response patterns with a simple retinal circuit.

    PubMed

    Werner, Birgit; Cook, Paul B; Passaglia, Christopher L

    2008-08-01

    The retina can respond to a wide array of features in the visual input. It was recently reported that the retina can even recognize complicated temporal input patterns and signal violations in the patterns. When a sequence of flashes was presented, ganglion cells exhibited a variety of firing profiles and many cells showed an "omitted stimulus response" (OSR), in which they fired strongly if a flash in the sequence was omitted. We examined the synaptic origins of the OSR by recording excitatory synaptic currents from ganglion cells in the salamander retina in response to periodic flash sequences. Consistent with previous spike recordings, ganglion cells exhibited an OSR in their current response and the OSR shifted in time with a change in flash frequency such that it could predict when the next flash should have occurred. Although the behavior may seem sophisticated, we show that a simple linear-nonlinear model with a spike threshold can account for the OSR in on ganglion cells and that the variety of complex firing profiles seen in other ganglion cells can be explained by adding contributions from the off pathway. We discuss the physiological and simulation results and their implications for understanding retinal mechanisms of visual information processing.

  7. Acoustic effects analysis utilizing speckle pattern with fixed-particle Monte Carlo

    NASA Astrophysics Data System (ADS)

    Vakili, Ali; Hollmann, Joseph A.; Holt, R. Glynn; DiMarzio, Charles A.

    2016-03-01

    Optical imaging in a turbid medium is limited because of multiple scattering a photon undergoes while traveling through the medium. Therefore, optical imaging is unable to provide high resolution information deep in the medium. In the case of soft tissue, acoustic waves unlike light, can travel through the medium with negligible scattering. However, acoustic waves cannot provide medically relevant contrast as good as light. Hybrid solutions have been applied to use the benefits of both imaging methods. A focused acoustic wave generates a force inside an acoustically absorbing medium known as acoustic radiation force (ARF). ARF induces particle displacement within the medium. The amount of displacement is a function of mechanical properties of the medium and the applied force. To monitor the displacement induced by the ARF, speckle pattern analysis can be used. The speckle pattern is the result of interfering optical waves with different phases. As light travels through the medium, it undergoes several scattering events. Hence, it generates different scattering paths which depends on the location of the particles. Light waves that travel along these paths have different phases (different optical path lengths). ARF induces displacement to scatterers within the acoustic focal volume, and changes the optical path length. In addition, temperature rise due to conversion of absorbed acoustic energy to heat, changes the index of refraction and therefore, changes the optical path length of the scattering paths. The result is a change in the speckle pattern. Results suggest that the average change in the speckle pattern measures the displacement of particles and temperature rise within the acoustic wave focal area, hence can provide mechanical and thermal properties of the medium.

  8. Spatial and Temporal Variability of Zooplankton Thin Layers: The Effects of Composition and Orientation on Acoustic Detection of Layers

    DTIC Science & Technology

    2008-01-01

    Spatial and Temporal Variability of Zooplankton Thin Layers: The Effects of Composition and Orientation...to better understand the physical and biological mechanisms of formation and maintenance of thin layers of zooplankton . Because zooplankton can be...strong sound scatterers, acoustic instruments are effective at detecting and describing zooplankton thin layers. Using a combination of instruments

  9. A Temporal Pattern Mining Approach for Classifying Electronic Health Record Data.

    PubMed

    Batal, Iyad; Valizadegan, Hamed; Cooper, Gregory F; Hauskrecht, Milos

    2013-09-01

    We study the problem of learning classification models from complex multivariate temporal data encountered in electronic health record systems. The challenge is to define a good set of features that are able to represent well the temporal aspect of the data. Our method relies on temporal abstractions and temporal pattern mining to extract the classification features. Temporal pattern mining usually returns a large number of temporal patterns, most of which may be irrelevant to the classification task. To address this problem, we present the Minimal Predictive Temporal Patterns framework to generate a small set of predictive and non-spurious patterns. We apply our approach to the real-world clinical task of predicting patients who are at risk of developing heparin induced thrombocytopenia. The results demonstrate the benefit of our approach in efficiently learning accurate classifiers, which is a key step for developing intelligent clinical monitoring systems.

  10. Spatial and temporal patterns of Risso's dolphin echolocation in the Southern California Bight.

    PubMed

    Soldevilla, Melissa S; Wiggins, Sean M; Hildebrand, John A

    2010-01-01

    Geographical and temporal trends in echolocation clicking activity can lead to insights into the foraging and migratory behaviors of pelagic dolphins. Using autonomous acoustic recording packages, the geographical, diel, and seasonal patterns of Risso's dolphin (Grampus griseus) echolocation click activity are described for six locations in the Southern California Bight between 2005 and 2007. Risso's dolphin echolocation click bouts are identified based on their unique spectral characteristics. Click bouts were identified on 739 of 1959 recording days at all 6 sites, with the majority occurring at nearshore sites. A significant diel pattern is evident in which both hourly occurrences of click bouts and click rates are higher at night than during the day. At all nearshore sites, Risso's dolphin clicks were identified year-round, with the highest daily occurrence at the southern end of Santa Catalina Island. Seasonal and interannual variabilities in occurrence were high across sites with peak occurrence in autumn of most years at most sites. These results suggest that Risso's dolphins forage at night and that the southern end of Santa Catalina Island represents an important habitat for Risso's dolphins throughout the year.

  11. 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

  12. Unravelling spatio-temporal evapotranspiration patterns in topographically complex landscapes

    NASA Astrophysics Data System (ADS)

    Metzen, Daniel; Sheridan, Gary; Nyman, Petter; Lane, Patrick

    2016-04-01

    Vegetation co-evolves with soils and topography under a given long-term climatic forcing. Previous studies demonstrated a strong eco-hydrologic feedback between topography, vegetation and energy and water fluxes. Slope orientation (aspect and gradient) alter the magnitude of incoming solar radiation resulting in larger evaporative losses and less water availability on equator-facing slopes. Furthermore, non-local water inputs from upslope areas potentially contribute to available water at downslope positions. The combined effect of slope orientation and drainage position creates complex spatial patterns in biological productivity and pedogenesis, which in turn alter the local hydrology. In complex upland landscapes, topographic alteration of incoming radiation can cause substantial aridity index (ratio of potential evapotranspiration to precipitation) variations over small spatial extents. Most of the upland forests in south-east Australia are located in an aridity index (AI) range of 1-2, around the energy limited to water limited boundary, where forested systems are expected to be most sensitive to AI changes. In this research we aim to improve the fundamental understanding of spatio-temporal evolution of evapotranspiration (ET) patterns in complex terrain, accounting for local topographic effects on system properties (e.g. soil depth, sapwood area, leaf area) and variation in energy and water exchange processes due to slope orientation and drainage position. Six measurement plots were set-up in a mixed species eucalypt forest on a polar and equatorial-facing hillslope (AI ˜1.3 vs. 1.8) at varying drainage position (ridge, mid-slope, gully), while minimizing variations in other factors, e.g. geology and weather patterns. Sap flow, soil water content, incoming solar radiation and throughfall were continuously monitored at field sites spanning a wide range of soil depth (0.5 - >3m), maximum tree heights (17 - 51m) and LAI (1.2 - 4.6). Site-specific response curves

  13. The temporal pattern of vitellogenin synthesis in Drosophila grimshawi

    SciTech Connect

    Kambysellis, M.P.; Hatzopoulos, P.; Craddock, E.M. )

    1989-09-01

    The temporal pattern of protein production and, in particular, vitellogenin protein synthesis during the sexual maturation of Drosophila grimshawi females has been studied in vivo by briefly feeding the flies with 35S-methionine and 3H-amino acids. The overall level of incorporation was very low in young flies; it then progressively increased to reach a maximum with the onset of sexual maturity at 13-15 days. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses revealed three classes of proteins: those synthesized throughout the age spectrum, which constitute the majority of protein species; proteins synthesized primarily or only in young flies; and proteins synthesized only by the older flies. In this Drosophila species, the three vitellogenins (V1, V2, and V3) appeared to be synthesized in a two-phase pattern. In the first phase, small quantities of V1 and V2 were detected immunologically in the fat body and hemolymph of newly emerged and 1 day-old flies. These proteins did not accumulate in the hemolymph or the ovaries, apparently being unstable proteins. The second phase commenced in early vitellogenesis (7-9 days of age) with synthesis in the fat body of small quantities of V1 and V2, followed by V3 proteins. These proteins were secreted and accumulated in the hemolymph and 24 h later were found in the ovaries. Their quantities increased rapidly and a steady state of synthesis, release into the hemolymph, and uptake by the ovaries was reached by days 13-15. We have estimated that during the steady state of vitellogenin synthesis, a fly can synthesize in 24 h at least 152 micrograms of vitellogenins, which is more than 2% of its body weight, at an average rate of about 6.3 micrograms vitellogenins/h. About 2 micrograms of this are synthesized in the fat body, and about 4 micrograms in the ovaries.

  14. Temporal Patterns in Diversity Change on Earth Over Time

    NASA Astrophysics Data System (ADS)

    Bambach, Richard

    2007-05-01

    Multi-celled animals and plants did not originate until about 600 million years ago. Since then the diversity of life has expanded greatly, but this has not been a monotonic increase. Diversity, as taxonomic variety or richness, is produced by the interaction of origination and extinction. Origination and extinction are almost equally balanced; it has taken 600 million years to accumulate 10 to 30 million living species. With most species life spans in the range of one to fifteen million years most species that have ever originated are extinct and global diversity has “turned over” many times. Paleontologists recognize about 18 short-term events of elevated extinction intensity and diversity loss of sufficient magnitude to warrant the term “mass extinction.” Interestingly, in only one instance, the end-Cretaceous extinction, is there a consensus for the triggering event, but the kill mechanism or mechanisms that caused the widespread death of lineages is not established. We know less about the cause-effect relationships for other events. Recently a 62 million-year periodicity in the fluctuation of diversity has been documented, expressed primarily in the variation of diversity of marine genera that survived 45 million years or less. Analysis of the pattern of diversity change at the finest temporal scale possible suggests that the short-term mass extinctions are superimposed on this regular pattern of diversity fluctuations, rather than causal of them. However, most mass extinctions (14 of 18) occurred during the intervals of general diversity loss. It remains to be seen how origination and extinction interact to produce the periodic fluctuation in diversity.

  15. 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.

  16. Spatio-temporal patterns of proportions of influenza B cases

    PubMed Central

    He, Daihai; Chiu, Alice P. Y.; Lin, Qianying; Yu, Duo

    2017-01-01

    We studied the spatio-temporal patterns of the proportions of influenza B cases out of all typed cases, with data from 139 countries and regions downloaded from the FluNet compiled by the World Health Organization, from January 2006 to October 2015. We restricted our analysis to 34 countries that reported more than 2,000 confirmations for each of types A and B over the study period. Globally, we found that Pearson’s correlation is greater than 0.6 between effective distance from Mexico and the proportions of influenza B cases among the countries during the post-pandemic era (i.e. Week 1, 2010 to Week 40, 2015). Locally, in the United States, the proportions of influenza B cases in the pre-pandemic period (2003–2008) negatively correlated with that in the post-pandemic era (2010–2015) at the regional level. Our study limitations are the country-level variations in both surveillance methods and testing policies. The proportions of influenza B cases displayed wide variations over the study period. Our findings suggest that the 2009 influenza pandemic has an evident impact on the relative burden of the two influenza types. Future studies should examine whether there are other additional factors. This study has potential implications in prioritizing public health control measures. PMID:28067277

  17. Temporal prediction of epidemic patterns in community networks

    NASA Astrophysics Data System (ADS)

    Peng, Xiao-Long; Small, Michael; Xu, Xin-Jian; Fu, Xinchu

    2013-11-01

    Most previous studies of epidemic dynamics on complex networks suppose that the disease will eventually stabilize at either a disease-free state or an endemic one. In reality, however, some epidemics always exhibit sporadic and recurrent behaviour in one region because of the invasion from an endemic population elsewhere. In this paper we address this issue and study a susceptible-infected-susceptible epidemiological model on a network consisting of two communities, where the disease is endemic in one community but alternates between outbreaks and extinctions in the other. We provide a detailed characterization of the temporal dynamics of epidemic patterns in the latter community. In particular, we investigate the time duration of both outbreak and extinction, and the time interval between two consecutive inter-community infections, as well as their frequency distributions. Based on the mean-field theory, we theoretically analyse these three timescales and their dependence on the average node degree of each community, the transmission parameters and the number of inter-community links, which are in good agreement with simulations, except when the probability of overlaps between successive outbreaks is too large. These findings aid us in better understanding the bursty nature of disease spreading in a local community, and thereby suggesting effective time-dependent control strategies.

  18. Pattern formation and temporal undulations of plane magnetic droplet

    NASA Astrophysics Data System (ADS)

    Singh, Chamkor; Das, Arup Kumar; Das, Prasanta Kumar

    2016-11-01

    In this study, we numerically investigate the time-dependent response of a ferrofluid droplet under an impulsively applied uniform magnetic field in a zero gravity environment. It is identified that two characteristic non-dimensional groups, namely, the Laplace number La and the magnetic Bond number Bom , primarily influence the response of the droplet. It is found that the nature of the time response can be either monotonic or undulating depending on the parameters. The transition between the two is smooth. In addition to the previously well-known regimes of elliptic and acicular ferrofluid droplet shapes, a new regime on the La - Bom plane is found where we observe some unique bifurcating patterns at the poles of the droplet. The temporal aperiodic to periodic mode transition on the La - Bom plane is found to be governed by La and the spatial droplet deformation and its final equilibrium configuration is found to be governed by Bom . The mechanism behind the elliptic to non-elliptic or elliptic to bifurcated shape transitions is discussed. The authors gratefully acknowledge the support of the Council of Scientific and Industrial Research, New Delhi, India, for the present work.

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

    SciTech Connect

    Ciddio, Manuela; Gatto, Marino Casagrandi, Renato

    2015-03-15

    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.

  20. Temporal and spatial patterns of wetland sedimentation, West Tennessee

    USGS Publications Warehouse

    Hupp, C.R.; Bazemore, D.E.

    1993-01-01

    Dendrogeomorphic techniques were used to describe and interpret patterns of sedimentation rates at two forested wetland sites in West Tennessee. Fifty-five sampling stations were established along transects upstream and downstream from bridge structures, and 515 trees were examined for depth of sediment accretion and cored for age determination. Temporal variation in sedimentation rate may be related more to stream channelization and agricultural activity than to bridge and causeway construction. Sedimentation rates have increased substantially in the last 28 years, although channelized streams may have overall lower rates than unchannelized streams. Comparisons of sedimentation rates from deposition over artificial markers (short term) with those determined from tree-ring analysis (long-term) indicate that trends are similar where hydrogeomorphic conditions have not been altered substantially. No tendency for increased sedimentation upstream from bridges was observed. Deposition rates were inversely correlated with elevation and degree of ponding. Downstream deposition of sand splays appears to be related to flow constrictions and may be extensive. Mean overall rates of sedimentation (between 0.24 and 0.28 cm year-1), determined dendrogeomorphically, are comparable with other published rates. ?? 1993.

  1. Air pollution in Accra neighborhoods: spatial, socioeconomic, and temporal patterns.

    PubMed

    Dionisio, Kathie L; Arku, Raphael E; Hughes, Allison F; Vallarino, Jose; Carmichael, Heather; Spengler, John D; Agyei-Mensah, Samuel; Ezzati, Majid

    2010-04-01

    This study examined the spatial, socioeconomic status (SES), and temporal patterns of ambient air pollution in Accra, Ghana. Over 22 months, integrated and continuous rooftop particulate matter (PM) monitors were placed at a total of 11 residential or roadside monitoring sites in four neighborhoods of varying SES and biomass fuel use. PM concentrations were highest in late December and January, due to dust blown from the Sahara. Excluding this period, annual PM(2.5) ranged from 39 to 53 microg/m(3) at roadside sites and 30 to 70 microg/m(3) at residential sites; mean annual PM(10) ranged from 80 to 108 microg/m(3) at roadside sites and 57 to 106 microg/m(3) at residential sites. The low-income and densely populated neighborhood of Jamestown/Ushertown had the single highest residential PM concentration. There was less difference across traffic sites. Daily PM increased at all sites at daybreak, followed by a mid-day peak at some sites, and a more spread-out evening peak at all sites. Average carbon monoxide concentrations at different sites and seasons ranged from 7 to 55 ppm, and were generally lower at residential sites than at traffic sites. The results show that PM in these four neighborhoods is substantially higher than the WHO Air Quality Guidelines and in some cases even higher than the WHO Interim Target 1, with the highest pollution in the poorest neighborhood.

  2. 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.

  3. Acoustic patterning for 3D embedded electrically conductive wire in stereolithography

    NASA Astrophysics Data System (ADS)

    Erdem Yunus, Doruk; Sohrabi, Salman; He, Ran; Shi, Wentao; Liu, Yaling

    2017-04-01

    In this paper, we reported a new approach for particle assembly with acoustic tweezers during three-dimensional (3D) printing, for the fabrication of embedded conductive wires with 3D structures. A hexagon shaped acoustic tweezer was incorporated with a digital light processing based stereolithography printer to pattern conductive lines via aligning and condensing conductive nanoparticles. The effect of filler content on electrical resistivity and pattern thickness were studied for copper, magnetite nanoparticles, and carbon nanofiber reinforced nanocomposite samples. The obtained data was later used to produce examples of conductive 3D microstructures and embedded electronic components by using the suggested method.

  4. Acoustic chaos

    SciTech Connect

    Lauterborn, W.; Parlitz, U.; Holzfuss, J.; Billo, A.; Akhatov, I.

    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.}

  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. 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.

  7. An Efficient Pattern Mining Approach for Event Detection in Multivariate Temporal Data.

    PubMed

    Batal, Iyad; Cooper, Gregory; Fradkin, Dmitriy; Harrison, James; Moerchen, Fabian; Hauskrecht, Milos

    2016-01-01

    This work proposes a pattern mining approach to learn event detection models from complex multivariate temporal data, such as electronic health records. We present Recent Temporal Pattern mining, a novel approach for efficiently finding predictive patterns for event detection problems. This approach first converts the time series data into time-interval sequences of temporal abstractions. It then constructs more complex time-interval patterns backward in time using temporal operators. We also present the Minimal Predictive Recent Temporal Patterns framework for selecting a small set of predictive and non-spurious patterns. We apply our methods for predicting adverse medical events in real-world clinical data. The results demonstrate the benefits of our methods in learning accurate event detection models, which is a key step for developing intelligent patient monitoring and decision support systems.

  8. An Efficient Pattern Mining Approach for Event Detection in Multivariate Temporal Data

    PubMed Central

    Batal, Iyad; Cooper, Gregory; Fradkin, Dmitriy; Harrison, James; Moerchen, Fabian; Hauskrecht, Milos

    2015-01-01

    This work proposes a pattern mining approach to learn event detection models from complex multivariate temporal data, such as electronic health records. We present Recent Temporal Pattern mining, a novel approach for efficiently finding predictive patterns for event detection problems. This approach first converts the time series data into time-interval sequences of temporal abstractions. It then constructs more complex time-interval patterns backward in time using temporal operators. We also present the Minimal Predictive Recent Temporal Patterns framework for selecting a small set of predictive and non-spurious patterns. We apply our methods for predicting adverse medical events in real-world clinical data. The results demonstrate the benefits of our methods in learning accurate event detection models, which is a key step for developing intelligent patient monitoring and decision support systems. PMID:26752800

  9. Temporal and Spatial Acoustical Factors for Listeners in the Boxes of Historical Opera Theatres

    NASA Astrophysics Data System (ADS)

    Sakai, H.; Ando, Y.; Prodi, N.; Pompoli, R.

    2002-11-01

    Acoustical measurements were conducted in a horseshoe-shaped opera house to clarify the acoustical quality of a sound field for listeners inside the boxes of an historical opera house. In order to investigate the effects of multiple reflections between the walls inside a box and scattering by the heads of people, the location of the receiver and the number of persons in the box were varied. In each configuration, four orthogonal factors and supplementary factors were derived as temporal and spatial factors by analysis of binaural impulse responses. Each factor is compared to that at a typical location in the stalls of the same theatre. An omni-directional sound source was located on the stage to emulate a singer or in the orchestra pit to reproduce the location of the musicians. Thus, in this paper, temporal and spatial factors in relation to subjective evaluation are characterized against changes in the listening conditions inside a box, and procedures for improvement and design methods for boxes are proposed. The main conclusions reached are as follows. As strong reflections from the lateral walls of a hall are screened by the front or side walls of a box for a receiver in a seat deeper in the box, the maximum listening level ( LL) in the boxes was observed at the front of the box, and the maximum range of LL values for each box was found to be 5 dB. Concerning the initial time delay gap ( Δt1), a more uniform listening environment was obtained in boxes further back in the theatre than in one closer to the stage. The subsequent reverberation time ( Tsub) lengthens for boxes closer to the stage due to the stage house with its huge volume, and a peak is observed at 1 kHz. For the box at the back, Tsub monotonically decreases with frequency in the same way as in the stalls, and moreover, its values approach those in the stalls. As the contribution of multiple reflections relatively increases for a receiver deeper in the box, the IACC in such positions decreases in

  10. Pattern recognition and tomography using crosswell acoustic data

    SciTech Connect

    Albright, J.N.; Terry, D.A.; Bradley, C.R.

    1985-01-01

    Measurements of the travel time of acoustic signals transmitted between wells at the Department of Energy Multi-Well Experiment site (MWX) near Rifle, Colorado, are processed and analyzed. Interpretations relevant to sand geometry and continuity have proved possible through inspection of the signal travel time plotted against the coordinates of transmitter and receiver wellbore positions, or against the depth of receiver and ray path inclination. The continuity of several sands between wells is corroborated. A major lenticular sand terminating between wells could be inferred. To explore the possible distortions in tomographic images derived from crosswell data, synthetic tomographs are constructed from computed travel times of signals transmitted through idealized models from stratigraphy thought to be present at the MWX site. The synthetic tomographs, although preserving the general character of the model stratigraphy, are distorted enough that detailed interpretations are not possible. Horizontal distortions predominate in reconstructions of flat-lying stratigraphy. 7 refs., 9 figs.

  11. Spatial and Temporal Patterns of Aerosol-Cloud Interactions

    NASA Astrophysics Data System (ADS)

    Fuchs, Julia; Cermak, Jan

    2014-05-01

    This study determines the spatial and temporal distribution of regions with frequent aerosol-cloud interactions (aci) and identifies their meteorological determinants based on CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) and ECMWF (European Centre for Medium-Range Weather Forecasts) data products. Atmospheric aerosols influence the microphysical structure of clouds, while both also respond to meteorological conditions. The potential radiative adjustments to changes in a cloud system associated with aerosol-cloud interactions are grouped and termed as effective radiative forcing due to aerosol-cloud interactions (ERFaci). It is difficult to distinguish, to what extent radiative forcing and precipitation patterns of clouds are a result of cloud feedbacks to aerosols or the existing meteorological conditions. A complete understanding of aerosol-cloud-meteorology interactions is crucial as the uncertainty range of ERFaci in climate change modeling could be significantly reduced. In the present study it is suggested that presence of hydrated aerosols is an implication for aci. Knowledge of their vertical and horizontal distribution and frequency over the globe would be important for understanding ERFaci. To identify regions with aerosol-cloud transitions the CAD score (cloud-aerosol discrimination) of the CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) instrument on the CALIPSO satellite is used. It separates aerosols and clouds according to the probability distribution functions of 5 parameters (attenuated backscatter, total color ratio, volume depolarization ratio, altitude and latitude) and assigns the likelihood of cloud or aerosol presence. This parameter is used to calculate relative frequencies of aci on a global scale from 2006 to 2013.

  12. Match analysis and temporal patterns of fatigue in rugby sevens.

    PubMed

    Granatelli, Giampietro; Gabbett, Tim J; Briotti, Gianluca; Padulo, Johnny; Buglione, Antonio; D'Ottavio, Stefano; Ruscello, Bruno M

    2014-03-01

    Rugby sevens is a rapidly growing sport. Match analysis is increasingly being used by sport scientists and coaches to improve the understanding of the physical demands of this sport. This study investigated the physical and physiological demands of elite men's rugby sevens, with special reference to the temporal patterns of fatigue during match play. Nine players, 4 backs and 5 forwards (age 25.1 ± 3.1 years) participated during 2 "Roma 7" international tournaments (2010 and 2011). All the players were at the professional level in the highest Italian rugby union, and 5 of these players also competed at the international level. During the matches (n = 15), the players were filmed to assess game performance. Global positioning system, heart rate (HR), and blood lactate (BLa) concentration data were measured and analyzed. The mean total distance covered throughout matches was 1,221 ± 118 m (first half = 643 ± 70 m and second half = 578 ± 77 m; with a decrease of 11.2%, p > 0.05, Effect Size [ES] = 0.29). The players achieved 88.3 ± 4.2 and 87.7 ± 3.4% of the HRmax during the first and second halves, respectively. The BLa for the first and second halves was 3.9 ± 0.9 and 11.2 ± 1.4 mmol·L, respectively. The decreases in performance occurred consistently in the final 3 minutes of the matches (-40.5% in the distance covered per minute). The difference found in relation to the playing position, although not statistically significant (p = 0.11), showed a large ES (η = 0.20), suggesting possible practical implications. These results demonstrate that rugby sevens is a demanding sport that places stress on both the anaerobic glycolytic and aerobic oxidative energy systems. Strength and conditioning programs designed to train these energy pathways may prevent fatigue-induced reductions in physical performance.

  13. Spatial and temporal patterns of subtidal and intertidal crabs excursions

    NASA Astrophysics Data System (ADS)

    Silva, A. C. F.; Boaventura, D. M.; Thompson, R. C.; Hawkins, S. J.

    2014-01-01

    Highly mobile predators such as fish and crabs are known to migrate from the subtidal zone to forage in the intertidal zone at high-tide. The extent and variation of these habitat linking movements along the vertical shore gradient have not been examined before for several species simultaneously, hence not accounting for species interactions. Here, the foraging excursions of Carcinus maenas (L.), Necora puber (Linnaeus, 1767) and Cancer pagurus (Linnaeus, 1758) were assessed in a one-year mark-recapture study on two replicated rocky shores in southwest U.K. A comparison between the abundance of individuals present on the shore at high-tide with those present in refuges exposed at low-tide indicated considerable intertidal migration by all species, showing strong linkage between subtidal and intertidal habitats. Estimates of population size based on recapture of marked individuals indicated that an average of ~ 4000 individuals combined for the three crab species, can be present on the shore during one tidal cycle. There was also a high fidelity of individuals and species to particular shore levels. Underlying mechanisms for these spatial patterns such as prey availability and agonistic interactions are discussed. Survival rates were estimated using the Cormack-Jolly-Seber model from multi-recapture analysis and found to be considerably high with a minimum of 30% for all species. Growth rates were found to vary intraspecifically with size and between seasons. Understanding the temporal and spatial variations in predation pressure by crabs on rocky shores is dependent on knowing who, when and how many of these commercially important crab species depend on intertidal foraging. Previous studies have shown that the diet of these species is strongly based on intertidal prey including key species such as limpets; hence intertidal crab migration could be associated with considerable impacts on intertidal assemblages.

  14. Temporal Patterns in Student Authorship: A Cross-National Perspective

    ERIC Educational Resources Information Center

    Foster, David

    2004-01-01

    While recent studies have demonstrated the importance of material structures in shaping writers' roles and practices in academic settings, relatively little attention has been focused on temporality, which exists as an embedded aspect of all such structures. Using the perspectives on temporality articulated in Anthony Giddens' concept of…

  15. Acoustically Evoked Different Vibration Pattern Across the Width of the Cochlea Partition

    NASA Astrophysics Data System (ADS)

    Zha, Dingjun; Chen, Fangyi; Friderberg, Anders; Choudhury, Niloy; Nuttall, Alfred

    2011-11-01

    Using optical low coherence interferometry, the acoustically evoked vibration patterns of the basilar membrane (BM) and reticular lamina (RL) in the first turn of living guinea pigs were measured as function of the radial location. It was demonstrated that the vibration of the BM varied widely in amplitude, but little in phase across the width of the partition, while the RL had a different vibration pattern compared with the BM.

  16. Acoustic Seaglider

    DTIC Science & Technology

    2008-03-07

    a national naval responsibility. Acoustic sensors on mobile, autonomous platforms will enable basic research topics on temporal and spatial...problem and acoustic navigation and communications within the context of distributed autonomous persistent undersea surveillance sensor networks...Acoustic sensors on mobile, autonomous platforms will enable basic research topics on temporal and spatial coherence and the description of ambient

  17. 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.

  18. 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.

  19. Spatio-temporal patterns of Campylobacter colonization in Danish broilers.

    PubMed

    Chowdhury, S; Themudo, G E; Sandberg, M; Ersbøll, A K

    2013-05-01

    Despite a number of risk-factor studies in different countries, the epidemiology of Campylobacter colonization in broilers, particularly spatial dependencies, is still not well understood. A series of analyses (visualization and exploratory) were therefore conducted in order to obtain a better understanding of the spatial and temporal distribution of Campylobacter in the Danish broiler population. In this study, we observed a non-random temporal occurrence of Campylobacter, with high prevalence during summer and low during winter. Significant spatio-temporal clusters were identified in the same areas in the summer months from 2007 to 2009. Range of influence between broiler farms were estimated at distances of 9.6 km and 13.5 km in different years. Identification of areas and time with greater risk indicates variable presence of risk factors with space and time. Implementation of safety measures on farms within high-risk clusters during summer could have an impact in reducing prevalence.

  20. Assessing the value of information in climber's guidebooks to derive spatio-temporal rockfall patterns

    NASA Astrophysics Data System (ADS)

    Temme, A. J. A. M.

    2012-04-01

    Rockfall rates in mountain ranges are expensive to measure over large spatial scales, mainly due to the inaccessibility of mountainous terrain. Existing methods to measure rockfall include acoustic methods (listening to the rock's impact or creation by frost weathering) , spectral methods (looking at the colour of mountain faces to determine their freshness and by extension the time since last rockfall) and volumetric methods (measuring the volume that fell). These methods, especially in combination, have allowed researchers to quantitatively derive rates (and distribution of rates over time) of rockfall for several well studied locations. However, the small spatial support of these methods means that results are only valid for small well-studied locations. This is a problem when we want to derive baseline information on rockfall rates over entire mountain chains and ranges - which is important to study their temporal distribution and their relation with climate change. This contribution explores the potential of information contained in climber's guidebooks to derive qualitative rockfall rates with large spatial and temporal coverage. Climber's guidebooks have been published since the early 1900's, giving prospective mountaineers strongly codified information about routes and conditions expected along the way. The information about the looseness of rocks, which is clearly important for climbers from a safety perspective, may also be useful to link to rockfall rates. I have used a series of guidebooks published at irregular intervals for the Bernese Oberland in Switzerland to study the change in descriptions of looseness of rocks for a number of famous climbing routes. These routes were selected because of the opportunity to complement information in guidebooks with other (visual and written) sources of information. Results indicate that descriptions of looseness of rock can be used to derive a qualitative pattern of rockfall, especially over larger spatial scales

  1. 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.

  2. 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.

    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.

  3. Dexterous acoustic trapping and patterning of particles assisted by phononic crystal plate

    SciTech Connect

    Wang, Tian; Ke, Manzhu Xu, Shengjun; Feng, Junheng; Qiu, Chunyin; Liu, Zhengyou

    2015-04-20

    In this letter, we present experimental demonstration of multi-particles trapping and patterning by the artificially engineered acoustic field of phononic crystal plate. Polystyrene particles are precisely trapped and patterned in two dimensional arrays, for example, the square, triangular, or quasi-periodic arrays, depending on the structures of the phononic crystal plates with varying sub-wavelength holes array. Analysis shows that the enhanced acoustic radiation force, induced by the resonant transmission field highly localized near the sub-wavelength apertures, accounts for the particles self-organizing. It can be envisaged that this kind of simple design of phononic crystal plates would pave an alternative route for self-assembly of particles and may be utilized in the lab-on-a-chip devices.

  4. Analysis of Nociceptive Information Encoded in the Temporal Discharge Patterns of Cutaneous C-Fibers

    PubMed Central

    Cho, Kyeongwon; Jang, Jun Ho; Kim, Sung-Phil; Lee, Sang Hoon; Chung, Soon-Cheol; Kim, In Young; Jang, Dong Pyo; Jung, Sung Jun

    2016-01-01

    The generation of pain signals from primary afferent neurons is explained by a labeled-line code. However, this notion cannot apply in a simple way to cutaneous C-fibers, which carry signals from a variety of receptors that respond to various stimuli including agonist chemicals. To represent the discharge patterns of C-fibers according to different agonist chemicals, we have developed a quantitative approach using three consecutive spikes. By using this method, the generation of pain in response to chemical stimuli is shown to be dependent on the temporal aspect of the spike trains. Furthermore, under pathological conditions, gamma-aminobutyric acid resulted in pain behavior without change of spike number but with an altered discharge pattern. Our results suggest that information about the agonist chemicals may be encoded in specific temporal patterns of signals in C-fibers, and nociceptive sensation may be influenced by the extent of temporal summation originating from the temporal patterns. PMID:27917120

  5. General asymmetric neutral networks and structure design by genetic algorithms: A learning rule for temporal patterns

    SciTech Connect

    Bornholdt, S.; Graudenz, D.

    1993-07-01

    A learning algorithm based on genetic algorithms for asymmetric neural networks with an arbitrary structure is presented. It is suited for the learning of temporal patterns and leads to stable neural networks with feedback.

  6. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  7. Behavioral and Single-Neuron Sensitivity to Millisecond Variations in Temporally Patterned Communication Signals

    PubMed Central

    Baker, Christa A.; Ma, Lisa; Casareale, Chelsea R.

    2016-01-01

    In many sensory pathways, central neurons serve as temporal filters for timing patterns in communication signals. However, how a population of neurons with diverse temporal filtering properties codes for natural variation in communication signals is unknown. Here we addressed this question in the weakly electric fish Brienomyrus brachyistius, which varies the time intervals between successive electric organ discharges to communicate. These fish produce an individually stereotyped signal called a scallop, which consists of a distinctive temporal pattern of ∼8–12 electric pulses. We manipulated the temporal structure of natural scallops during behavioral playback and in vivo electrophysiology experiments to probe the temporal sensitivity of scallop encoding and recognition. We found that presenting time-reversed, randomized, or jittered scallops increased behavioral response thresholds, demonstrating that fish's electric signaling behavior was sensitive to the precise temporal structure of scallops. Next, using in vivo intracellular recordings and discriminant function analysis, we found that the responses of interval-selective midbrain neurons were also sensitive to the precise temporal structure of scallops. Subthreshold changes in membrane potential recorded from single neurons discriminated natural scallops from time-reversed, randomized, and jittered sequences. Pooling the responses of multiple neurons improved the discriminability of natural sequences from temporally manipulated sequences. Finally, we found that single-neuron responses were sensitive to interindividual variation in scallop sequences, raising the question of whether fish may analyze scallop structure to gain information about the sender. Collectively, these results demonstrate that a population of interval-selective neurons can encode behaviorally relevant temporal patterns with millisecond precision. SIGNIFICANCE STATEMENT The timing patterns of action potentials, or spikes, play important

  8. Analysis of spatial-temporal gene expression patterns reveals dynamics and regionalization in developing mouse brain.

    PubMed

    Chou, Shen-Ju; Wang, Chindi; Sintupisut, Nardnisa; Niou, Zhen-Xian; Lin, Chih-Hsu; Li, Ker-Chau; Yeang, Chen-Hsiang

    2016-01-20

    Allen Brain Atlas (ABA) provides a valuable resource of spatial/temporal gene expressions in mammalian brains. Despite rich information extracted from this database, current analyses suffer from several limitations. First, most studies are either gene-centric or region-centric, thus are inadequate to capture the superposition of multiple spatial-temporal patterns. Second, standard tools of expression analysis such as matrix factorization can capture those patterns but do not explicitly incorporate spatial dependency. To overcome those limitations, we proposed a computational method to detect recurrent patterns in the spatial-temporal gene expression data of developing mouse brains. We demonstrated that regional distinction in brain development could be revealed by localized gene expression patterns. The patterns expressed in the forebrain, medullary and pontomedullary, and basal ganglia are enriched with genes involved in forebrain development, locomotory behavior, and dopamine metabolism respectively. In addition, the timing of global gene expression patterns reflects the general trends of molecular events in mouse brain development. Furthermore, we validated functional implications of the inferred patterns by showing genes sharing similar spatial-temporal expression patterns with Lhx2 exhibited differential expression in the embryonic forebrains of Lhx2 mutant mice. These analysis outcomes confirm the utility of recurrent expression patterns in studying brain development.

  9. Dissociation of psychophysical and EEG steady-state response measures of cross-modal temporal correspondence for amplitude modulated acoustic and vibrotactile stimulation.

    PubMed

    Timora, Justin R; Budd, Timothy W

    2013-09-01

    Research examining multisensory integration suggests that the correspondence of stimulus characteristics across modalities (cross-modal correspondence) can have a dramatic influence on both neurophysiological and perceptual responses to multimodal stimulation. The current study extends prior research by examining the cross-modal correspondence of amplitude modulation rate for simultaneous acoustic and vibrotactile stimulation using EEG and perceptual measures of sensitivity to amplitude modulation. To achieve this, psychophysical thresholds and steady-state responses (SSRs) were measured for acoustic and vibrotactile amplitude modulated (AM) stimulation for 21 and 40 Hz AM rates as a function of the cross-modal correspondence. The study design included three primary conditions to determine whether the changes in the SSR and psychophysical thresholds were due to the cross-modal temporal correspondence of amplitude modulated stimuli: NONE (AM in one modality only), SAME (the same AM rate for each modality) and DIFF (different AM rates for each modality). The results of the psychophysical analysis showed that AM detection thresholds for the simultaneous AM conditions (i.e., SAME and DIFF) were significantly higher (i.e., lower sensitivity) than AM detection thresholds for the stimulation of a single modality (i.e., NONE). SSR results showed significant effects of SAME and DIFF conditions on SSR activity. The different pattern of results for perceptual and SSR measures of cross-modal correspondence of AM rate indicates a dissociation between entrained cortical activity (i.e., SSR) and perception.

  10. Two-dimensional single-cell patterning with one cell per well driven by surface acoustic waves

    PubMed Central

    Collins, David J.; Morahan, Belinda; Garcia-Bustos, Jose; Doerig, Christian; Plebanski, Magdalena; Neild, Adrian

    2015-01-01

    In single-cell analysis, cellular activity and parameters are assayed on an individual, rather than population-average basis. Essential to observing the activity of these cells over time is the ability to trap, pattern and retain them, for which previous single-cell-patterning work has principally made use of mechanical methods. While successful as a long-term cell-patterning strategy, these devices remain essentially single use. Here we introduce a new method for the patterning of multiple spatially separated single particles and cells using high-frequency acoustic fields with one cell per acoustic well. We characterize and demonstrate patterning for both a range of particle sizes and the capture and patterning of cells, including human lymphocytes and red blood cells infected by the malarial parasite Plasmodium falciparum. This ability is made possible by a hitherto unexplored regime where the acoustic wavelength is on the same order as the cell dimensions. PMID:26522429

  11. Two-dimensional single-cell patterning with one cell per well driven by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Collins, David J.; Morahan, Belinda; Garcia-Bustos, Jose; Doerig, Christian; Plebanski, Magdalena; Neild, Adrian

    2015-11-01

    In single-cell analysis, cellular activity and parameters are assayed on an individual, rather than population-average basis. Essential to observing the activity of these cells over time is the ability to trap, pattern and retain them, for which previous single-cell-patterning work has principally made use of mechanical methods. While successful as a long-term cell-patterning strategy, these devices remain essentially single use. Here we introduce a new method for the patterning of multiple spatially separated single particles and cells using high-frequency acoustic fields with one cell per acoustic well. We characterize and demonstrate patterning for both a range of particle sizes and the capture and patterning of cells, including human lymphocytes and red blood cells infected by the malarial parasite Plasmodium falciparum. This ability is made possible by a hitherto unexplored regime where the acoustic wavelength is on the same order as the cell dimensions.

  12. Acoustic correlates of English rhythmic patterns for American versus Japanese speakers.

    PubMed

    Mori, Yoko; Hori, Tomoko; Erickson, Donna

    2014-01-01

    This study investigates acoustic correlates of English rhythmic patterns for 20 American English speakers (AS) and 42 Japanese learners of English (JS). The results indicate that for AS in an English sentence where monosyllabic content and function words alternate, the vowels in content words are over twice as long as those in function words, resulting in alternating long-short vowels. In contrast, the JS show no stress-related duration control and realize a similar rhythmic pattern mostly through recursive high-low fundamental frequency (F0). In a sentence with a sequence of content words in which 4 stressed syllables occur successively, the AS show recursion of strong-weak syllables by means of F0, intensity and first formant, whereas JS show inconsistent stress patterns. These results indicate that the AS apply different strategies for implementing rhythmic alternation depending on sentence stress patterns, and these strategies are different from those of JS.

  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.

  14. Temporal Patterns of Gene Expression During Calyx of Held Development

    PubMed Central

    Kolson, D. R.; Wan, J.; Wu, J.; Dehoff, M.; Brandebura, A. N.; Qian, J.; Mathers, P. H.; Spirou, G. A.

    2015-01-01

    Relating changes in gene expression to discrete developmental events remains an elusive challenge in neuroscience, in part because most neural territories are comprised of multiple cell types that mature over extended periods of time. The medial nucleus of the trapezoid body (MNTB) is an attractive vertebrate model system that contains a nearly homogeneous population of neurons, which are innervated by large glutamatergic nerve terminals called calyces of Held (CH). Key steps in maturation of CHs and MNTB neurons, including CH growth and competition, occur very quickly for most cells between postnatal days (P)2 and P6. Therefore, we characterized genome-wide changes in this system, with dense temporal sampling during the first postnatal week. We identified 541 genes whose expression changed significantly between P0–6 and clustered them into eight groups based on temporal expression profiles. Candidate genes from each of the eight profile groups were validated in separate samples by qPCR. Our tissue sample permitted comparison of known glial and neuronal transcripts and revealed that monotonically increasing or decreasing expression profiles tended to be associated with glia and neurons, respectively. Gene ontology revealed enrichment of genes involved in axon pathfinding, cell differentiation, cell adhesion and extracellular matrix. The latter category included elements of perineuronal nets, a prominent feature of MNTB neurons that is morphologically distinct by P6, when CH growth and competition are resolved onto nearly all MNTB neurons. These results provide a genetic framework for investigation of general mechanisms responsible for nerve terminal growth and maturation. PMID:26014473

  15. Cultural and environmental influences on temporal-spectral development patterns of corn and soybeans

    NASA Technical Reports Server (NTRS)

    Crist, E. P.

    1982-01-01

    A technique for evaluating crop temporal-spectral development patterns is described and applied to the analysis of cropping practices and environmental conditions as they affect reflectance characteristics of corn and soybean canopies. Typical variations in field conditions are shown to exert significant influences on the spectral development patterns, and thereby to affect the separability of the two crops.

  16. Dissociation of visual and auditory pattern discrimination functions within the cat's temporal cortex.

    PubMed

    Cornwell, P; Nudo, R J; Straussfogel, D; Lomber, S G; Payne, B R

    1998-08-01

    In ablation-behavior experiments performed in adult cats, a double dissociation was demonstrated between ventral posterior suprasylvian cortex (vPS) and temporo-insular cortex (TI) lesions on complex visual and auditory tasks. Lesions of the vPS cortex resulted in deficits at visual pattern discrimination, but not at a difficult auditory discrimination. By contrast, TI lesions resulted in profound deficits at discriminating complex sounds, but not at discriminating visual patterns. This pattern of dissociation of deficits in cats parallels the dissociation of deficits after inferior temporal versus superior temporal lesions in monkeys and humans.

  17. Temporal Patterns in Seawater Quality from Dredging in Tropical Environments

    PubMed Central

    Jones, Ross; Fisher, Rebecca; Stark, Clair; Ridd, Peter

    2015-01-01

    Maintenance and capital dredging represents a potential risk to tropical environments, especially in turbidity-sensitive environments such as coral reefs. There is little detailed, published observational time-series data that quantifies how dredging affects seawater quality conditions temporally and spatially. This information is needed to test realistic exposure scenarios to better understand the seawater-quality implications of dredging and ultimately to better predict and manage impacts of future projects. Using data from three recent major capital dredging programs in North Western Australia, the extent and duration of natural (baseline) and dredging-related turbidity events are described over periods ranging from hours to weeks. Very close to dredging i.e. <500 m distance, a characteristic features of these particular case studies was high temporal variability. Over several hours suspended sediment concentrations (SSCs) can range from 100–500 mg L-1. Less turbid conditions (10–80 mg L-1) can persist over several days but over longer periods (weeks to months) averages were <10 mg L-1. During turbidity events all benthic light was sometimes extinguished, even in the shallow reefal environment, however a much more common feature was very low light ‘caliginous’ or daytime twilight periods. Compared to pre-dredging conditions, dredging increased the intensity, duration and frequency of the turbidity events by 10-, 5- and 3-fold respectively (at sites <500 m from dredging). However, when averaged across the entire dredging period of 80–180 weeks, turbidity values only increased by 2–3 fold above pre-dredging levels. Similarly, the upper percentile values (e.g., P99, P95) of seawater quality parameters can be highly elevated over short periods, but converge to values only marginally above baseline states over longer periods. Dredging in these studies altered the overall probability density distribution, increasing the frequency of extreme values. As such

  18. 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.

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

    PubMed Central

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

    2014-01-01

    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. Temporal patterns in seedling establishment on pocket gopher disturbances.

    PubMed

    Forbis, Tara A; Larmore, Jason; Addis, Elizabeth

    2004-01-01

    Disturbances often facilitate seedling establishment, and can change the species composition of a community by increasing recruitment of disturbance-adapted species. To understand the effects of pocket gopher disturbances on alpine seedling dynamics, we examined the gopher disturbances' effects on seedling emergence and survival on gopher disturbances 0 to 5 years old. In contrast to results from most other ecosystems, these recently created gopher mounds had lower seedling emergence and survival rates than undisturbed areas. A lack of correlation between species' abundances on gopher mounds and undisturbed sites in one of the two communities studied suggested that a suite of disturbance-adapted species recruited onto the mounds. To explain low seedling emergence on recent gopher mounds, we quantified gopher mound seed banks and studied recruitment in a site with mounds that ranged from 0 to >20 years old. Seed numbers in first-year gopher mound soils were extremely low relative to undisturbed soils, and this pattern was mirrored in seedling establishment patterns over the long term. Gopher disturbance depressed seedling emergence density for the first 5 years. Subsequently, emergence density increased until at least 20 years following the disturbance. Emergence on disturbances more than 20 years old was higher than on undisturbed sites. Therefore, gopher disturbances probably facilitate seedling establishment in alpine dry and moist meadow; however, this process takes place over decades.

  1. Temporal Variabilities in Genetic Patterns and Antibiotic Resistance Profiles of Enterococci Isolated from Human Feces

    PubMed Central

    Nishiyama, Masateru; Shimauchi, Hidetaka; Suzuki, Yoshihiro

    2016-01-01

    Temporal variabilities in the genetic patterns and antibiotic resistance profiles of enterococci were monitored over a 7-month period. Enterococcus faecalis isolates (103 strains) collected from feces showed only one genetic pattern and antibiotic resistance profile within 0 d and 30 d. In contrast, after 60 d and 90 d, the genetic patterns and antibiotic resistance profiles of all E. faecalis isolates (8 strains) clearly differed within 30 d. These results indicate that the genetic patterns and antibiotic resistance profiles of E. faecalis in human feces changed to completely dissimilar patterns between 1 and 2 months. PMID:27265342

  2. Spatial and Temporal Patterns in Carbon Emissions to the Atmosphere

    NASA Astrophysics Data System (ADS)

    Broniak, C. T.; Blasing, T. J.; Marland, G.

    2003-12-01

    Data on global fossil-fuel emissions of CO2 to the atmosphere for year 2000 show that the range of national average per capita emissions, in metric tons of carbon per person, includes values of 5.40 for the United States, 2.61 for Germany, 0.29 for India and 0.04 for Liberia. This range is more than two orders of magnitude. Similar data on national fossil-fuel emissions for the United States vary by more than an order of magnitude, from 34.18 metric tons of carbon per person for Wyoming to 2.70 for California. The state data also show differing patterns of change over time. The Kyoto Protocol would require ratifying developed countries to reduce greenhouse gas emissions to quantified negotiated targets. The concept of contraction and convergence (C&C) has been widely touted as a possible basis for ultimate, more strict limits on greenhouse gas emissions. The idea of C&C is that per-capita emissions of CO2 for all countries would converge toward some common value that is consistent with stabilization of global climate. The U.S., on the other hand, has proposed intensity-based emissions targets whereby goals would be defined in terms of emissions per unit of gross domestic product, or perhaps emissions per unit of output for specific activities. This paper describes the data set on U.S. CO2 emissions by state, and begins to explore the patterns between states and over time.

  3. Discrimination of speech stimuli based on neuronal response phase patterns depends on acoustics but not comprehension.

    PubMed

    Howard, Mary F; Poeppel, David

    2010-11-01

    Speech stimuli give rise to neural activity in the listener that can be observed as waveforms using magnetoencephalography. Although waveforms vary greatly from trial to trial due to activity unrelated to the stimulus, it has been demonstrated that spoken sentences can be discriminated based on theta-band (3-7 Hz) phase patterns in single-trial response waveforms. Furthermore, manipulations of the speech signal envelope and fine structure that reduced intelligibility were found to produce correlated reductions in discrimination performance, suggesting a relationship between theta-band phase patterns and speech comprehension. This study investigates the nature of this relationship, hypothesizing that theta-band phase patterns primarily reflect cortical processing of low-frequency (<40 Hz) modulations present in the acoustic signal and required for intelligibility, rather than processing exclusively related to comprehension (e.g., lexical, syntactic, semantic). Using stimuli that are quite similar to normal spoken sentences in terms of low-frequency modulation characteristics but are unintelligible (i.e., their time-inverted counterparts), we find that discrimination performance based on theta-band phase patterns is equal for both types of stimuli. Consistent with earlier findings, we also observe that whereas theta-band phase patterns differ across stimuli, power patterns do not. We use a simulation model of the single-trial response to spoken sentence stimuli to demonstrate that phase-locked responses to low-frequency modulations of the acoustic signal can account not only for the phase but also for the power results. The simulation offers insight into the interpretation of the empirical results with respect to phase-resetting and power-enhancement models of the evoked response.

  4. Discrimination of Speech Stimuli Based on Neuronal Response Phase Patterns Depends on Acoustics But Not Comprehension

    PubMed Central

    Poeppel, David

    2010-01-01

    Speech stimuli give rise to neural activity in the listener that can be observed as waveforms using magnetoencephalography. Although waveforms vary greatly from trial to trial due to activity unrelated to the stimulus, it has been demonstrated that spoken sentences can be discriminated based on theta-band (3–7 Hz) phase patterns in single-trial response waveforms. Furthermore, manipulations of the speech signal envelope and fine structure that reduced intelligibility were found to produce correlated reductions in discrimination performance, suggesting a relationship between theta-band phase patterns and speech comprehension. This study investigates the nature of this relationship, hypothesizing that theta-band phase patterns primarily reflect cortical processing of low-frequency (<40 Hz) modulations present in the acoustic signal and required for intelligibility, rather than processing exclusively related to comprehension (e.g., lexical, syntactic, semantic). Using stimuli that are quite similar to normal spoken sentences in terms of low-frequency modulation characteristics but are unintelligible (i.e., their time-inverted counterparts), we find that discrimination performance based on theta-band phase patterns is equal for both types of stimuli. Consistent with earlier findings, we also observe that whereas theta-band phase patterns differ across stimuli, power patterns do not. We use a simulation model of the single-trial response to spoken sentence stimuli to demonstrate that phase-locked responses to low-frequency modulations of the acoustic signal can account not only for the phase but also for the power results. The simulation offers insight into the interpretation of the empirical results with respect to phase-resetting and power-enhancement models of the evoked response. PMID:20484530

  5. Near perfect ultrasonic omnidirectional transducer using the optimal patterning of the zero-index acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Hyun, Jaeyub; Wang, Semyung

    2016-11-01

    This study proposes the theoretical optimal patterning method based on the geometrical transformation acoustics to design an ultrasonic omnidirectional transducer system, which is composed of the designed near zero-index acoustic metamaterial (ZIAMM). The designed ZIAMM is made of circular rubber rods in water matrix. Meanwhile, the curved unit cell structure is necessary to arrange the designed ZIAMM effectively into the circular-shaped ultrasonic omnidirectional transducer system. To this end, we transform the square unit cell into the curved unit cell in the physical space, instead of starting from a homogeneous medium. Also the periodic boundary condition in the two-dimensional polar coordinate is proposed to calculate the dynamic characteristic (i.e., the effective material properties and the dispersion relation) according to the curvature of curved unit cell. The proposed optimal patterning method is verified through the ZIAMM-based ultrasonic omnidirectional transducer system. Especially the radiation performance of ZIAMM-based ultrasonic omnidirectional transducer system is greatly improved by this optimal patterning.

  6. Pattern recognition techniques applied to acoustic detection of liquid-metal fast breeder reactor cooling defects

    SciTech Connect

    Brunet, M.; Dubuisson, B.

    1983-08-01

    In the event of a partial or total blockage of a liquid-metal fast breeder reactor core subassembly, a boiling zone may be created. Acoustic signals from such a zone could provide a means of early detection of accident conditions. A three-step method, based on pattern recognition techniques, is described and used to analyze data from three experiments that simulate core cooling fault conditions. This method is shown to be capable of detecting the abnormal situation in each of the experiments analyzed.

  7. Patterns of temporal scaling of groundwater level fluctuation

    NASA Astrophysics Data System (ADS)

    Yu, Xue; Ghasemizadeh, Reza; Padilla, Ingrid Y.; Kaeli, David; Alshawabkeh, Akram

    2016-05-01

    We studied the fractal scaling behavior of groundwater level fluctuation for various types of aquifers in Puerto Rico using the methods of (1) detrended fluctuation analysis (DFA) to examine the monofractality and (2) wavelet transform maximum modulus (WTMM) to analyze the multifractality. The DFA results show that fractals exist in groundwater fluctuations of all the aquifers with scaling patterns that are anti-persistent (1 < β < 1.5; 1.32 ± 0.12, 18 wells) or persistent (β > 1.5; 1.62 ± 0.07, 4 wells). The multifractal analysis confirmed the need to characterize these highly complex processes with multifractality, which originated from the stochastic distribution of the irregularly-shaped fluctuations. The singularity spectra of the fluctuation processes in each well were site specific. We found a general elevational effect with smaller fractal scaling coefficients in the shallower wells, except for the Northern Karst Aquifer Upper System. High spatial variability of fractal scaling of groundwater level fluctuations in the karst aquifer is due to the coupled effects of anthropogenic perturbations, precipitation, elevation and particularly the high heterogeneous hydrogeological conditions.

  8. Monoaminergic influences on temporal patterning of sexual behavior in male rats.

    PubMed

    Yells, D P; Prendergast, M A; Hendricks, S E; Miller, M E

    1995-11-01

    We evaluated the effects of the serotonin (5-HT) presynaptic uptake blocker fluoxetine (FLX) and the dopamine (DA)/noradrenaline (NE) releaser amantadine (AMA), separately and in combination, on the temporal patterning of male rat sexual behavior. FLX alone increased intermount-bout intervals, time-outs, grooming time, ejaculation latency, number of mounts per mount bout, and number of mount bouts per ejaculation. AMA alone had the opposite effect on these measures. Additionally, AMA, when given in combination with FLX, completely reversed the FLX-induced deficits in copulatory behavior. We interpret our results as suggesting an interaction between 5-HT and catecholamines in the temporal patterning of male rat copulatory behavior.

  9. Geochemical and temporal patterns of felsic volcanism in Ethiopia

    SciTech Connect

    Walter, R.C.; Westgate, J.A.; Giday, W.G.; Aronson, J.L.; Hart, W.K.

    1985-01-01

    At least three major geochemical groups characterize late Cenozoic felsic volcanism exposed in the central Ethiopian Rift graben or along its uplifted margins. Each group is distinguished by age and/or position with distinctive compositional traits that are probably tectonically controlled. They include: (1) large-volume Pliocene tholeiitic to calcalkaline rhyolitic ignimbrites that form >500m thick exposures along the rift margins. These have moderate FeO/sub T/ (1.5-3.0%), low CaO (<0.5%) and moderately steep REE slopes (Ce/Yb = 21-24) with large negative Eu anomalies (Eu/Eu* = 0.2-0.4). K/Ar ages range from 4.5 to 3.0 Ma. These ignimbrites must have been associated with major caldera-forming events, but no calderas of this age or chemistry have yet been found; (2) Plio-Pleistocene trachytic volcanoes occur on the Ethiopian Highland, parallel to the rift axis. These have low SiO/sub 2/ (60-70%), high FeO/sub T/ (4-8%) and steep REE patterns (Ce/Yb = 25-37) with very small negative Eu anomalies (0.8-0.9). The volcanoes of Chilalo, Kaka, Hunkulu and the Bada Range are of this group. K/Ar ages range from 3.5 to 1.0 Ma; (3) Pleistocene peralkaline rhyolitic volcanoes of the Ethiopian Rift graben have high FeO/sub T/ (5-8%), high Na/sub 2/O (6-8%) and shallow REE profiles (Ce/Yb = 14-21) with small Eu anomalies (0.5 to 0.6). K/Ar ages range from 0.5 to <0.05 Ma. The volcanoes of Aluto and Dofen are of this group. Eruption of Group 1 signaled the modern rapid development of the present rift; Group 2 overlapped in time and mainly was confined to the Plateau margins; and Group 3 represents the present mature stage of rift floor volcanism.

  10. Temporal Patterns in Fine Particulate Matter Time Series in Beijing: A Calendar View.

    PubMed

    Liu, Jianzheng; Li, Jie; Li, Weifeng

    2016-08-26

    Extremely high fine particulate matter (PM2.5) concentration has become synonymous to Beijing, the capital of China, posing critical challenges to its sustainable development and leading to major public health concerns. In order to formulate mitigation measures and policies, knowledge on PM2.5 variation patterns should be obtained. While previous studies are limited either because of availability of data, or because of problematic a priori assumptions that PM2.5 concentration follows subjective seasonal, monthly, or weekly patterns, our study aims to reveal the data on a daily basis through visualization rather than imposing subjective periodic patterns upon the data. To achieve this, we conduct two time-series cluster analyses on full-year PM2.5 data in Beijing in 2014, and provide an innovative calendar visualization of PM2.5 measurements throughout the year. Insights from the analysis on temporal variation of PM2.5 concentration show that there are three diurnal patterns and no weekly patterns; seasonal patterns exist but they do not follow a strict temporal division. These findings advance current understanding on temporal patterns in PM2.5 data and offer a different perspective which can help with policy formulation on PM2.5 mitigation.

  11. Temporal Patterns in Fine Particulate Matter Time Series in Beijing: A Calendar View

    PubMed Central

    Liu, Jianzheng; Li, Jie; Li, Weifeng

    2016-01-01

    Extremely high fine particulate matter (PM2.5) concentration has become synonymous to Beijing, the capital of China, posing critical challenges to its sustainable development and leading to major public health concerns. In order to formulate mitigation measures and policies, knowledge on PM2.5 variation patterns should be obtained. While previous studies are limited either because of availability of data, or because of problematic a priori assumptions that PM2.5 concentration follows subjective seasonal, monthly, or weekly patterns, our study aims to reveal the data on a daily basis through visualization rather than imposing subjective periodic patterns upon the data. To achieve this, we conduct two time-series cluster analyses on full-year PM2.5 data in Beijing in 2014, and provide an innovative calendar visualization of PM2.5 measurements throughout the year. Insights from the analysis on temporal variation of PM2.5 concentration show that there are three diurnal patterns and no weekly patterns; seasonal patterns exist but they do not follow a strict temporal division. These findings advance current understanding on temporal patterns in PM2.5 data and offer a different perspective which can help with policy formulation on PM2.5 mitigation. PMID:27561629

  12. Temporal Patterns in Fine Particulate Matter Time Series in Beijing: A Calendar View

    NASA Astrophysics Data System (ADS)

    Liu, Jianzheng; Li, Jie; Li, Weifeng

    2016-08-01

    Extremely high fine particulate matter (PM2.5) concentration has become synonymous to Beijing, the capital of China, posing critical challenges to its sustainable development and leading to major public health concerns. In order to formulate mitigation measures and policies, knowledge on PM2.5 variation patterns should be obtained. While previous studies are limited either because of availability of data, or because of problematic a priori assumptions that PM2.5 concentration follows subjective seasonal, monthly, or weekly patterns, our study aims to reveal the data on a daily basis through visualization rather than imposing subjective periodic patterns upon the data. To achieve this, we conduct two time-series cluster analyses on full-year PM2.5 data in Beijing in 2014, and provide an innovative calendar visualization of PM2.5 measurements throughout the year. Insights from the analysis on temporal variation of PM2.5 concentration show that there are three diurnal patterns and no weekly patterns; seasonal patterns exist but they do not follow a strict temporal division. These findings advance current understanding on temporal patterns in PM2.5 data and offer a different perspective which can help with policy formulation on PM2.5 mitigation.

  13. 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

    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.

  14. 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.

  15. Problems Associated with Statistical Pattern Recognition of Acoustic Emission Signals in a Compact Tension Fatigue Specimen

    NASA Technical Reports Server (NTRS)

    Hinton, Yolanda L.

    1999-01-01

    Acoustic emission (AE) data were acquired during fatigue testing of an aluminum 2024-T4 compact tension specimen using a commercially available AE system. AE signals from crack extension were identified and separated from noise spikes, signals that reflected from the specimen edges, and signals that saturated the instrumentation. A commercially available software package was used to train a statistical pattern recognition system to classify the signals. The software trained a network to recognize signals with a 91-percent accuracy when compared with the researcher's interpretation of the data. Reasons for the discrepancies are examined and it is postulated that additional preprocessing of the AE data to focus on the extensional wave mode and eliminate other effects before training the pattern recognition system will result in increased accuracy.

  16. Precise Manipulation and Patterning of Protein Crystals for Macromolecular Crystallography using Surface Acoustic Waves

    PubMed Central

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

    2015-01-01

    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 we have developed a surface acoustic wave-based method for manipulating and patterning crystals. This method, which does not damage the fragile protein crystals, can precisely manipulate and pattern micrometer and sub-micrometer 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 also will make it possible to collect data on samples that were previously intractable. PMID:25641793

  17. Temporal analysis of feeding patterns of Culex erraticus in central Alabama.

    PubMed

    Oliveira, Ana; Katholi, Charles R; Burkett-Cadena, Nathan; Hassan, Hassan K; Kristensen, Sibylle; Unnasch, Thomas R

    2011-04-01

    Host blood meals in seven mosquito species previously shown to be infected with eastern equine encephalitis virus at a site in the Tuskegee National Forest in southcentral Alabama were investigated. Of 1374 blood meals derived from 88 different host species collected over 6 years from these seven mosquito species, 1099 were derived from Culex erraticus. Analysis of the temporal pattern of Cx. erraticus meals using a Runs test revealed that the patterns of feeding upon avian and mammalian hosts from March to September of each year were not randomly distributed over time. Similarly, meals taken from the three most commonly targeted host species (yellow-crowned night heron, great blue heron, and white-tailed deer) were not randomly distributed. A Tukey's two-way analysis of variance test demonstrated that although the temporal pattern of meals taken from avian hosts were consistent over the years, the patterns of meals taken from the individual host species were not consistent from year to year.

  18. Spatio-temporal expression patterns of anterior Hox genes during Nile tilapia (Oreochromis niloticus) embryonic development.

    PubMed

    Lyon, R Stewart; Davis, Adam; Scemama, Jean-Luc

    2013-01-01

    Hox genes encode transcription factors that function to pattern regional tissue identities along the anterior-posterior axis during animal embryonic development. Divergent nested Hox gene expression patterns within the posterior pharyngeal arches may play an important role in patterning morphological variation in the pharyngeal jaw apparatus (PJA) between evolutionarily divergent teleost fishes. Recent gene expression studies have shown the expression patterns from all Hox paralog group (PG) 2-6 genes in the posterior pharyngeal arches (PAs) for the Japanese medaka (Oryzias latipes) and from most genes of these PGs for the Nile tilapia (Oreochromis niloticus). While several orthologous Hox genes exhibit divergent spatial and temporal expression patterns between these two teleost species in the posterior PAs, several tilapia Hox gene expression patterns from PG3-6 must be documented for a full comparative study. Here we present the spatio-temporal expression patterns of hoxb3b, c3a, b4a, a5a, b5a, b5b, b6a and b6b in the neural tube and posterior PAs of the Nile tilapia. We show that several of these tilapia Hox genes exhibit divergent expression patterns in the posterior PAs from their medaka orthologs. We also compare these gene expression patterns to orthologs in other gnathostome vertebrates, including the dogfish shark.

  19. Temporal variability and stability in infant-directed sung speech: evidence for language-specific patterns.

    PubMed

    Falk, Simone

    2011-06-01

    In this paper, sung speech is used as a methodological tool to explore temporal variability in the timing of word-internal consonants and vowels. It is hypothesized that temporal variability/stability becomes clearer under the varying rhythmical conditions induced by song.This is explored crosslinguistically in German - a language that exhibits a potential vocalic quantity distinction - and the non-quantity languages French and Russian. Songs by non-professional singers, i.e. parents that sang to their infants aged 2 to 13 months in a non-laboratory setting, were recorded and analyzed.Vowel and consonant durations at syllable contacts of trochaic word types with CVCV or CV:CV structure were measured under varying rhythmical conditions. Evidence is provided that in German non-professional singing, the two syllable structures can be differentiated by two distinct temporal variability patterns: vocalic variability (and consonantal stability) was found to be dominant in CV:CV structures whereas consonantal variability (and vocalic stability) was characteristic for CVCV structures. In French and Russian, however, only vocalic variability seemed to apply.Additionally, findings suggest that the different temporal patterns found in German were also supported by the stability pattern at the tonal level. These results point to subtle (supra) segmental timing mechanisms in sung speech that affect temporal targets according to the specific prosodic nature of the language in question.

  20. 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

  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. 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...

  4. Interrelationships Among Warmth, Genuineness, Empathy, And Temporal Speech Patterns In Interpersonal Interaction

    ERIC Educational Resources Information Center

    Welkowitz, Joan; Kuc, Marta

    1973-01-01

    This study explores interrelationships among ratings by conversational partners and independent observers of empathy, warmth, and genuineness, and relates these ratings to partners' dialogue patterns. The results support the hypothesis that one of the parameters of temporal congruence, switching pauses, relates significantly to ratings of warmth…

  5. Auditory Temporal Pattern Perception in 6- and 12-Month-Old Infants.

    ERIC Educational Resources Information Center

    Morrongiello, Barbara A.

    1984-01-01

    A go/no-go conditioned head-turn paradigm was used to examine the abilities of 6- and 12-month-olds to discriminate changes in temporal grouping and their perception of absolute and relative timing information when listening to patterns of white-noise bursts. (Author/RH)

  6. Reconstruction of missing data in social networks based on temporal patterns of interactions

    NASA Astrophysics Data System (ADS)

    Stomakhin, Alexey; Short, Martin B.; Bertozzi, Andrea L.

    2011-11-01

    We discuss a mathematical framework based on a self-exciting point process aimed at analyzing temporal patterns in the series of interaction events between agents in a social network. We then develop a reconstruction model that allows one to predict the unknown participants in a portion of those events. Finally, we apply our results to the Los Angeles gang network.

  7. Acoustic Cluster Therapy: In Vitro and Ex Vivo Measurement of Activated Bubble Size Distribution and Temporal Dynamics.

    PubMed

    Healey, Andrew John; Sontum, Per Christian; Kvåle, Svein; Eriksen, Morten; Bendiksen, Ragnar; Tornes, Audun; Østensen, Jonny

    2016-05-01

    Acoustic cluster technology (ACT) is a two-component, microparticle formulation platform being developed for ultrasound-mediated drug delivery. Sonazoid microbubbles, which have a negative surface charge, are mixed with micron-sized perfluoromethylcyclopentane droplets stabilized with a positively charged surface membrane to form microbubble/microdroplet clusters. On exposure to ultrasound, the oil undergoes a phase change to the gaseous state, generating 20- to 40-μm ACT bubbles. An acoustic transmission technique is used to measure absorption and velocity dispersion of the ACT bubbles. An inversion technique computes bubble size population with temporal resolution of seconds. Bubble populations are measured both in vitro and in vivo after activation within the cardiac chambers of a dog model, with catheter-based flow through an extracorporeal measurement flow chamber. Volume-weighted mean diameter in arterial blood after activation in the left ventricle was 22 μm, with no bubbles >44 μm in diameter. After intravenous administration, 24.4% of the oil is activated in the cardiac chambers.

  8. 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

  9. The precise temporal pattern of prehearing spontaneous activity is necessary for tonotopic map refinement.

    PubMed

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

    2014-05-21

    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 α9 subunit of nicotinic acetylcholine receptors (α9 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.

  10. 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.

  11. Phase demodulation from a spatial carrier fringe pattern by spatial-temporal fringes method

    NASA Astrophysics Data System (ADS)

    Lan, Bin; Feng, Guoying; Zhang, Tao; Zhou, Shouhuan

    2016-12-01

    Phase extraction from a single fringe pattern is a valuable but challenging task. In this paper, a spatial carrier phase-shifting algorithm based on spatial-temporal fringes method is proposed to demodulate the phase from a single carrier interfergram. Firstly, two phase-shifted fringe patterns are composed from the original interferogram shifting by several pixels their starting position. Secondly, these two phase shift fringes are fused into one spatial-temporal fringes (STF) image. Then, the modulating phase is calculated from the frequency spectrum of the STF image. Meanwhile, the main factors, such as the level of random noise, the carrier frequency values and angle of fringe pattern are analyzed and discussed in the simulations, and experimental results are given to demonstrate the validity of the proposed method. The proposed method is effective, accurate and immune to external disturbance and vibration, which greatly promotes the application in the on-line detection fields.

  12. Temporal pattern of incorporation of /sup 3/H precursors into pituitary glycoproteins and their subsequent release

    SciTech Connect

    Grotjan, H.E. Jr.

    1982-04-01

    The temporal pattern of incorporation of various /sup 3/H precursors into glycoproteins by rat anterior pituitaries incubated in vitro and the release of /sup 3/H-glycoproteins was examined. (/sup 3/H)Leucine incorporation was linear with respect to time and (/sup 3/H)leucine-containing macromolecules appeared in the media in about 1 hr. The temporal pattern of (/sup 3/H)mannose incorporation and release was similar. (/sup 3/H)Galactose and (/sup 3/H)fucose were incorporated after apparent time of delays of approximately 15 min and soon thereafter (20-25 min) appeared in the medium in /sup 3/H-glycoproteins. Thus, these precursors appear to be added as terminal residues. (/sup 3/H)Glucosamine exhibited a pattern intermediate between (/sup 3/H)leucine and (/sup 3/H)fucose whereas (/sup 3/H)GlcNAc appeared to be incorporated as a terminal residue.

  13. 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.

  14. COMPOSE: Using temporal patterns for interpreting wearable sensor data with computer interpretable guidelines.

    PubMed

    Urovi, V; Jimenez-Del-Toro, O; Dubosson, F; Ruiz Torres, A; Schumacher, M I

    2017-02-01

    This paper describes a novel temporal logic-based framework for reasoning with continuous data collected from wearable sensors. The work is motivated by the Metabolic Syndrome, a cluster of conditions which are linked to obesity and unhealthy lifestyle. We assume that, by interpreting the physiological parameters of continuous monitoring, we can identify which patients have a higher risk of Metabolic Syndrome. We define temporal patterns for reasoning with continuous data and specify the coordination mechanisms for combining different sets of clinical guidelines that relate to this condition. The proposed solution is tested with data provided by twenty subjects, which used sensors for four days of continuous monitoring. The results are compared to the gold standard. The novelty of the framework stands in extending a temporal logic formalism, namely the Event Calculus, with temporal patterns. These patterns are helpful to specify the rules for reasoning with continuous data and in combining new knowledge into one consistent outcome that is tailored to the patient's profile. The overall approach opens new possibilities for delivering patient-tailored interventions and educational material before the patients present the symptoms of the disease.

  15. Ipsilateral blinking seizures during left fronto-temporal ictal pattern on scalp EEG.

    PubMed

    Pestana, Elia M; Gupta, Ajay

    2007-12-01

    We report an infant with left eye blinking seizures accompanying a left (ipsilateral) fronto-temporal scalp EEG ictal pattern. The epileptogenic lesion was a left frontal encephalomalacia along the ventriculo-peritoneal shunt tract. The shunt was inserted for treatment of communicating hydrocephalus. This case illustrates the lateralizing value of the ictal blinking. Review of the literature suggests that seizures with unilateral blinking are likely to be produced by activation of ipsilateral trigeminal fibers innervating subdural intracranial structures and pial vessels in temporal and frontal lobes. Ipsilateral blinking could also be produced by activation of the ipsilateral cerebellar hemisphere.

  16. 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

  17. 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

  18. Spatial and temporal patterns of cloud cover and fog inundation in coastal California: Ecological implications

    USGS Publications Warehouse

    Rastogi, Bharat; Williams, A. Park; Fischer, Douglas T.; Iacobellis, Sam F.; McEachern, Kathryn; Carvalho, Leila; Jones, Charles Leslie; Baguskas, Sara A.; Still, Christopher J.

    2016-01-01

    The presence of low-lying stratocumulus clouds and fog has been known to modify biophysical and ecological properties in coastal California where forests are frequently shaded by low-lying clouds or immersed in fog during otherwise warm and dry summer months. Summer fog and stratus can ameliorate summer drought stress and enhance soil water budgets, and often have different spatial and temporal patterns. Here we use remote sensing datasets to characterize the spatial and temporal patterns of cloud cover over California’s northern Channel Islands. We found marine stratus to be persistent from May through September across the years 2001-2012. Stratus clouds were both most frequent and had the greatest spatial extent in July. Clouds typically formed in the evening, and dissipated by the following early afternoon. We present a novel method to downscale satellite imagery using atmospheric observations and discriminate patterns of fog from those of stratus and help explain patterns of fog deposition previously studied on the islands. The outcomes of this study contribute significantly to our ability to quantify the occurrence of coastal fog at biologically meaningful spatial and temporal scales that can improve our understanding of cloud-ecosystem interactions, species distributions and coastal ecohydrology.

  19. Spatial and temporal air quality pattern recognition using environmetric techniques: a case study in Malaysia.

    PubMed

    Syed Abdul Mutalib, Sharifah Norsukhairin; Juahir, Hafizan; Azid, Azman; Mohd Sharif, Sharifah; Latif, Mohd Talib; Aris, Ahmad Zaharin; Zain, Sharifuddin M; Dominick, Doreena

    2013-09-01

    The objective of this study is to identify spatial and temporal patterns in the air quality at three selected Malaysian air monitoring stations based on an eleven-year database (January 2000-December 2010). Four statistical methods, Discriminant Analysis (DA), Hierarchical Agglomerative Cluster Analysis (HACA), Principal Component Analysis (PCA) and Artificial Neural Networks (ANNs), were selected to analyze the datasets of five air quality parameters, namely: SO2, NO2, O3, CO and particulate matter with a diameter size of below 10 μm (PM10). The three selected air monitoring stations share the characteristic of being located in highly urbanized areas and are surrounded by a number of industries. The DA results show that spatial characterizations allow successful discrimination between the three stations, while HACA shows the temporal pattern from the monthly and yearly factor analysis which correlates with severe haze episodes that have happened in this country at certain periods of time. The PCA results show that the major source of air pollution is mostly due to the combustion of fossil fuel in motor vehicles and industrial activities. The spatial pattern recognition (S-ANN) results show a better prediction performance in discriminating between the regions, with an excellent percentage of correct classification compared to DA. This study presents the necessity and usefulness of environmetric techniques for the interpretation of large datasets aiming to obtain better information about air quality patterns based on spatial and temporal characterizations at the selected air monitoring stations.

  20. Tracking pedestrians using local spatio-temporal motion patterns in extremely crowded scenes.

    PubMed

    Kratz, Louis; Nishino, Ko

    2012-05-01

    Tracking pedestrians is a vital component of many computer vision applications, including surveillance, scene understanding, and behavior analysis. Videos of crowded scenes present significant challenges to tracking due to the large number of pedestrians and the frequent partial occlusions that they produce. The movement of each pedestrian, however, contributes to the overall crowd motion (i.e., the collective motions of the scene's constituents over the entire video) that exhibits an underlying spatially and temporally varying structured pattern. In this paper, we present a novel Bayesian framework for tracking pedestrians in videos of crowded scenes using a space-time model of the crowd motion. We represent the crowd motion with a collection of hidden Markov models trained on local spatio-temporal motion patterns, i.e., the motion patterns exhibited by pedestrians as they move through local space-time regions of the video. Using this unique representation, we predict the next local spatio-temporal motion pattern a tracked pedestrian will exhibit based on the observed frames of the video. We then use this prediction as a prior for tracking the movement of an individual in videos of extremely crowded scenes. We show that our approach of leveraging the crowd motion enables tracking in videos of complex scenes that present unique difficulty to other approaches.

  1. Temporal consistency of spatial pattern in growth of the mussel, Mytilus edulis: Implications for predictive modelling

    NASA Astrophysics Data System (ADS)

    Bergström, Per; Lindegarth, Susanne; Lindegarth, Mats

    2013-10-01

    Human pressures on coastal seas are increasing and methods for sustainable management, including spatial planning and mitigative actions, are therefore needed. In coastal areas worldwide, the development of mussel farming as an economically and ecologically sustainable industry requires geographic information on the growth and potential production capacity. In practice this means that coherent maps of temporally stable spatial patterns of growth need to be available in the planning process and that maps need to be based on mechanistic or empirical models. Therefore, as a first step towards development of models of growth, we assessed empirically the fundamental requirement that there are temporally consistent spatial patterns of growth in the blue mussel, Mytilus edulis. Using a pilot study we designed and dimensioned a transplant experiment, where the spatial consistency in the growth of mussels was evaluated at two resolutions. We found strong temporal and scale-dependent spatial variability in growth but patterns suggested that spatial patterns were uncoupled between growth of shell and that of soft tissue. Spatial patterns of shell growth were complex and largely inconsistent among years. Importantly, however, the growth of soft tissue was qualitatively consistent among years at the scale of km. The results suggest that processes affecting the whole coastal area cause substantial differences in growth of soft tissue among years but that factors varying at the scale of km create strong and persistent spatial patterns of growth, with a potential doubling of productivity by identifying the most suitable locations. We conclude that the observed spatial consistency provides a basis for further development of predictive modelling and mapping of soft tissue growth in these coastal areas. Potential causes of observed patterns, consequences for mussel-farming as a tool for mitigating eutrophication, aspects of precision of modelling and sampling of mussel growth as well

  2. 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

  3. Brain responses in humans reveal ideal observer-like sensitivity to complex acoustic patterns

    PubMed Central

    Pearce, Marcus T.; Griffiths, Timothy D.; Chait, Maria

    2016-01-01

    We use behavioral methods, magnetoencephalography, and functional MRI to investigate how human listeners discover temporal patterns and statistical regularities in complex sound sequences. Sensitivity to patterns is fundamental to sensory processing, in particular in the auditory system, because most auditory signals only have meaning as successions over time. Previous evidence suggests that the brain is tuned to the statistics of sensory stimulation. However, the process through which this arises has been elusive. We demonstrate that listeners are remarkably sensitive to the emergence of complex patterns within rapidly evolving sound sequences, performing on par with an ideal observer model. Brain responses reveal online processes of evidence accumulation—dynamic changes in tonic activity precisely correlate with the expected precision or predictability of ongoing auditory input—both in terms of deterministic (first-order) structure and the entropy of random sequences. Source analysis demonstrates an interaction between primary auditory cortex, hippocampus, and inferior frontal gyrus in the process of discovering the regularity within the ongoing sound sequence. The results are consistent with precision based predictive coding accounts of perceptual inference and provide compelling neurophysiological evidence of the brain's capacity to encode high-order temporal structure in sensory signals. PMID:26787854

  4. Spatio-temporal patterns of Cu contamination in mosses using geostatistical estimation.

    PubMed

    Martins, Anabela; Figueira, Rui; Sousa, António Jorge; Sérgio, Cecília

    2012-11-01

    Several recent studies have reported temporal trends in metal contamination in mosses, but such assessments did not evaluate uncertainty in temporal changes, therefore providing weak statistical support for time comparisons. Furthermore, levels of contaminants in the environment change in both space and time, requiring space-time modelling methods for map estimation. We propose an indicator of spatial and temporal variation based on space-time estimation by indicator kriging, where uncertainty at each location is estimated from the local distribution function, thereby calculating variability intervals for comparison between several biomonitoring dates. This approach was exemplified using copper concentrations in mosses from four Portuguese surveys (1992, 1997, 2002 and 2006). Using this approach, we identified a general decrease in copper contamination, but spatial patterns were not uniform, and from the uncertainty intervals, changes could not be considered significant in the majority of the study area.

  5. 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

  6. Identification of the neighborhood and CA rules from spatio-temporal CA patterns.

    PubMed

    Billings, S A; Yang, Yingxu

    2003-01-01

    Extracting the rules from spatio-temporal patterns generated by the evolution of cellular automata (CA) usually produces a CA rule table without providing a clear understanding of the structure of the neighborhood or the CA rule. In this paper, a new identification method based on using a modified orthogonal least squares or CA-OLS algorithm to detect the neighborhood structure and the underlying polynomial form of the CA rules is proposed. The Quine-McCluskey method is then applied to extract minimum Boolean expressions from the polynomials. Spatio-temporal patterns produced by the evolution of 1D, 2D, and higher dimensional binary CAs are used to illustrate the new algorithm, and simulation results show that the CA-OLS algorithm can quickly select both the correct neighborhood structure and the corresponding rule.

  7. Reliability of spatial and temporal patterns of C. finmarchicus inferred from the CPR survey

    NASA Astrophysics Data System (ADS)

    Hélaouët, Pierre; Beaugrand, Grégory; Reygondeau, Gabriel

    2016-01-01

    The Continuous Plankton Recorder (CPR) survey has collected plankton since 1958 in the North Atlantic Ocean and its adjacent seas. Among all species recorded by the CPR, Calanus finmarchicus has probably been the most investigated species because of its ecological importance for the temperate and subpolar regions of the North Atlantic Ocean. However, abundances of C. finmarchicus assessed from the CPR survey have been rarely compared to more traditional sampling methodologies. In this study, we examine and compare spatial (surface and vertical) and temporal (diel and seasonal) patterns in the abundance of C. finmarchicus with another sampling technique in the gulf of Maine. Our results provide evidence that the CPR survey not only gives internally consistent time series of C. finmarchicus, but also an accurate representation of both spatial (surface and vertical) and temporal (diel and seasonal) patterns.

  8. Temporal metastates are associated with differential patterns of time-resolved connectivity, network topology, and attention

    PubMed Central

    Shine, James M.; Koyejo, Oluwasanmi; Poldrack, Russell A.

    2016-01-01

    Little is currently known about the coordination of neural activity over longitudinal timescales and how these changes relate to behavior. To investigate this issue, we used resting-state fMRI data from a single individual to identify the presence of two distinct temporal states that fluctuated over the course of 18 mo. These temporal states were associated with distinct patterns of time-resolved blood oxygen level dependent (BOLD) connectivity within individual scanning sessions and also related to significant alterations in global efficiency of brain connectivity as well as differences in self-reported attention. These patterns were replicated in a separate longitudinal dataset, providing additional supportive evidence for the presence of fluctuations in functional network topology over time. Together, our results underscore the importance of longitudinal phenotyping in cognitive neuroscience. PMID:27528672

  9. Variable Temporal Integration of Stimulus Patterns in the Mouse Barrel Cortex.

    PubMed

    Pitas, Anna; Albarracín, Ana Lía; Molano-Mazón, Manuel; Maravall, Miguel

    2016-02-01

    Making sense of the world requires distinguishing temporal patterns and sequences lasting hundreds of milliseconds or more. How cortical circuits integrate over time to represent specific sensory sequences remains elusive. Here we assessed whether neurons in the barrel cortex (BC) integrate information about temporal patterns of whisker movements. We performed cell-attached recordings in anesthetized mice while delivering whisker deflections at variable intervals and compared the information carried by neurons about the latest interstimulus interval (reflecting sensitivity to instantaneous frequency) and earlier intervals (reflecting integration over timescales up to several hundred milliseconds). Neurons carried more information about the latest interval than earlier ones. The amount of temporal integration varied with neuronal responsiveness and with the cortical depth of the recording site, that is, with laminar location. A subset of neurons in the upper layers displayed the strongest integration. Highly responsive neurons in the deeper layers encoded the latest interval but integrated particularly weakly. Under these conditions, BC neurons act primarily as encoders of current stimulation parameters; however, our results suggest that temporal integration over hundreds of milliseconds can emerge in some neurons within BC.

  10. Temporal patterns of native Mandarin Chinese speakers' productions of English stop-vowel syllable

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Behne, Dawn M.

    2004-05-01

    Second language (L2) production can be a kind of interlanguage, a relatively stable system bearing the nature of both the native language (L1) and L2. Within such a system sound components of a syllable may bear their own interlanguage characteristics and yet interact with the other component sounds. The present study investigates temporal patterns of L1-L2 interaction at the syllable level. Audio recordings were made of English stop-vowel syllables produced by native speakers of Mandarin who were fluent in English (ChE). Native English productions (AmE) of these syllables and native productions of Mandarin (ChM) stop-vowel syllables were acquired as native norms. Temporal measures included stop closure duration, voice-onset time (VOT), vowel duration, and syllable duration. Results show that the internal timing components of ChE often deviate from AmE, with the closure duration, VOT, and vowel duration being intermediate to AmE and ChM. However, at the syllable level, ChE productions tend to follow the overall patterns of AmE. Temporal deviations were often compensated by temporal compensation of other components in the syllable, maintaining a balanced consonant/vowel distribution. These findings have implications for a broader understanding of L2 productions.

  11. Temporal patterns of native Mandarin Chinese speakers' productions of English stop-vowel syllable

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Behne, Dawn M.

    2001-05-01

    Second language (L2) production can be a kind of interlanguage, a relatively stable system bearing the nature of both the native language (L1) and L2. Within such a system sound components of a syllable may bear their own interlanguage characteristics and yet interact with the other component sounds. The present study investigates temporal patterns of L1-L2 interaction at the syllable level. Audio recordings were made of English stop-vowel syllables produced by native speakers of Mandarin who were fluent in English (ChE). Native English productions (AmE) of these syllables and native productions of Mandarin (ChM) stop-vowel syllables were acquired as native norms. Temporal measures included stop closure duration, voice-onset time (VOT), vowel duration, and syllable duration. Results show that the internal timing components of ChE often deviate from AmE, with the closure duration, VOT, and vowel duration being intermediate to AmE and ChM. However, at the syllable level, ChE productions tend to follow the overall patterns of AmE. Temporal deviations were often compensated by temporal compensation of other components in the syllable, maintaining a balanced consonant/vowel distribution. These findings have implications for a broader understanding of L2 productions.

  12. Active processing of spatio-temporal input patterns in silicon dendrites.

    PubMed

    Wang, Yingxue; Liu, Shih-Chii

    2013-06-01

    Capturing the functionality of active dendritic processing into abstract mathematical models will help us to understand the role of complex biophysical neurons in neuronal computation and to build future useful neuromorphic analog Very Large Scale Integrated (aVLSI) neuronal devices. Previous work based on an aVLSI multi-compartmental neuron model demonstrates that the compartmental response in the presence of either of two widely studied classes of active mechanisms, is a nonlinear sigmoidal function of the degree of either input temporal synchrony OR input clustering level. Using the same silicon model, this work expounds the interaction between both active mechanisms in a compartment receiving input patterns of varying temporal AND spatial clustering structure and demonstrates that this compartmental response can be captured by a combined sigmoid and radial-basis function over both input dimensions. This paper further shows that the response to input spatio-temporal patterns in a one-dimensional multi-compartmental dendrite, can be described by a radial-basis like function of the degree of temporal synchrony between the inter-compartmental inputs.

  13. 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.

  14. Continuous sheathless microparticle and cell patterning using CL-SSAWs (conductive liquid-based standing surface acoustic waves)

    NASA Astrophysics Data System (ADS)

    Nam, Jeonghun; Kim, Jae Young; Lim, Chae Seung

    2017-01-01

    We present continuous, sheathless microparticle patterning using conductive liquid (CL)-based standing surface acoustic waves (SSAWs). Conventional metal electrodes patterned on a piezoelectric substrate were replaced with electrode channels filled with a CL. The device performance was evaluated with 5-μm fluorescent polystyrene particles at different flow rate and via phase shifting. In addition, our device was further applied to continuous concentration of malaria parasites at the sidewalls of the fluidic channel.

  15. Spatial and temporal patterns in macrofaunal diversity components relative to sea floor landscape structure.

    PubMed

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

    2013-01-01

    We examined temporal changes in macrofaunal α- and β-diversity over several spatial scales (within patches, among patches, across landscapes and across regions) in Long Island Sound on the northeast USA coast. Regional ε-diversity was estimated at 144 taxa, however γ-diversity fluctuated over time as did α- and β-diversity components. Based on additive partitioning, patch- and region-scale β-diversity components generally had the highest contributions to γ-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 β-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 β-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

  16. Temporal coherence among tropical coastal lagoons: a search for patterns and mechanisms.

    PubMed

    Caliman, A; Carneiro, L S; Santangelo, J M; Guariento, R D; Pires, A P F; Suhett, A L; Quesado, L B; Scofield, V; Fonte, E S; Lopes, P M; Sanches, L F; Azevedo, F D; Marinho, C C; Bozelli, R L; Esteves, F A; Farjalla, V F

    2010-10-01

    Temporal coherence (i.e., the degree of synchronicity of a given variable among ecological units within a predefined space) has been shown for several limnological features among temperate lakes, allowing predictions about the structure and function of ecosystems. However, there is little evidence of temporal coherence among tropical aquatic systems, where the climatic variability among seasons is less pronounced. Here, we used data from long-term monitoring of physical, chemical and biological variables to test the degree of temporal coherence among 18 tropical coastal lagoons. The water temperature and chlorophyll-a concentration had the highest and lowest temporal coherence among the lagoons, respectively, whereas the salinity and water colour had intermediate temporal coherence. The regional climactic factors were the main factors responsible for the coherence patterns in the water temperature and water colour, whereas the landscape position and morphometric characteristics explained much of the variation of the salinity and water colour among the lagoons. These results indicate that both local (lagoon morphometry) and regional (precipitation, air temperature) factors regulate the physical and chemical conditions of coastal lagoons by adjusting the terrestrial and marine subsidies at a landscape-scale. On the other hand, the chlorophyll-a concentration appears to be primarily regulated by specific local conditions resulting in a weak temporal coherence among the ecosystems. We concluded that temporal coherence in tropical ecosystems is possible, at least for some environmental features, and should be evaluated for other tropical ecosystems. Our results also reinforce that aquatic ecosystems should be studied more broadly to accomplish a full understanding of their structure and function.

  17. Lactase gene promoter fragments mediate differential spatial and temporal expression patterns in transgenic mice.

    PubMed

    Wang, Zhi; Maravelias, Charalambos; Sibley, Eric

    2006-04-01

    Lactase gene expression is spatiotemporally regulated during mammalian gut development. We hypothesize that distinct DNA control regions specify appropriate spatial and temporal patterning of lactase gene expression. In order to define regions of the lactase promoter involved in mediating intestine-specific and spatiotemporal restricted expression, transgenic mice harboring 100 bp, 1.3- and 2.0- kb fragments of the 5' flanking region of the rat lactase gene cloned upstream of a luciferase reporter were characterized. The 100-bp lactase promoter-reporter transgenic mouse line expressed maximal luciferase activity in the intestine with a posterior shift in spatial restriction and ectopic expression in the stomach and lung. The temporal pattern of expression mediated by the 1.3-kb promoter?reporter transgene increases with postnatal maturation in contrast with the postnatal decline mediated by the 2.0-kb promoter-reporter transgene and the endogenous lactase gene. The differential transgene expression patterns mediated by the lactase promoter fragments suggests that intestine-specific spatial and temporal control elements reside in distinct regions of the DNA sequences upstream of the lactase gene transcription start-site.

  18. The Temporal Pattern, Flux, and Function of Autophagy in Spinal Cord Injury

    PubMed Central

    Zhou, Kailiang; Sansur, Charles A.; Xu, Huazi; Jia, Xiaofeng

    2017-01-01

    Previous studies have indicated that autophagy plays a critical role in spinal cord injury (SCI), including traumatic spinal cord injury (TSCI) and ischemia-reperfusion spinal cord injury (IRSCI). However, while the understanding of mechanisms underlying autophagy in SCI has progressed, there remain several controversial points: (1) temporal pattern results of autophagic activation after SCI are not consistent across studies; (2) effect of accumulation of autophagosomes due to the blockade or enhancement of autophagic flux is uncertain; (3) overall effect of enhanced autophagy remains undefined, with both beneficial and detrimental outcomes reported in SCI literature. In this review, the temporal pattern of autophagic activation, autophagic flux, autophagic cell death, relationship between autophagy and apoptosis, and pharmacological intervention of autophagy in TSCI (contusion injury, compression injury and hemisection injury) and IRSCI are discussed. Types of SCI and severity appear to contribute to differences in outcomes regarding temporal pattern, flux, and function of autophagy. With future development of specific strategies on autophagy intervention, autophagy may play an important role in improving functional recovery in patients with SCI. PMID:28230791

  19. How can a recurrent neurodynamic predictive coding model cope with fluctuation in temporal patterns? Robotic experiments on imitative interaction.

    PubMed

    Ahmadi, Ahmadreza; Tani, Jun

    2017-03-21

    The current paper examines how a recurrent neural network (RNN) model using a dynamic predictive coding scheme can cope with fluctuations in temporal patterns through generalization in learning. The conjecture driving this present inquiry is that a RNN model with multiple timescales (MTRNN) learns by extracting patterns of change from observed temporal patterns, developing an internal dynamic structure such that variance in initial internal states account for modulations in corresponding observed patterns. We trained a MTRNN with low-dimensional temporal patterns, and assessed performance on an imitation task employing these patterns. Analysis reveals that imitating fluctuated patterns consists in inferring optimal internal states by error regression. The model was then tested through humanoid robotic experiments requiring imitative interaction with human subjects. Results show that spontaneous and lively interaction can be achieved as the model successfully copes with fluctuations naturally occurring in human movement patterns.

  20. Patterns of acoustical activity of bats prior to and following White-nose Syndrome occurrence

    USGS Publications Warehouse

    Ford, W. Mark; Britzke, Eric R.; Dobony, Christopher A.; Rodrigue, Jane L.; Johnson, Joshua B.

    2011-01-01

    White-nose Syndrome (WNS), a wildlife health concern that has decimated cave-hibernating bat populations in eastern North America since 2006, began affecting source-caves for summer bat populations at Fort Drum, a U.S. Army installation in New York in the winter of 2007–2008. As regional die-offs of bats became evident, and Fort Drum's known populations began showing declines, we examined whether WNS-induced change in abundance patterns and seasonal timing of bat activity could be quantified using acoustical surveys, 2003–2010, at structurally uncluttered riparian–water habitats (i.e., streams, ponds, and wet meadows). As predicted, we observed significant declines in overall summer activity between pre-WNS and post-WNS years for little brown bats Myotis lucifugus, northern bats M. septentrionalis, and Indiana bats M. sodalis. We did not observe any significant change in activity patterns between pre-WNS and post-WNS years for big brown bats Eptesicus fuscus, eastern red bats Lasiurus borealis, or the small number of tri-colored bats Perimyotis subflavus. Activity of silver-haired bats Lasionycteris noctivagans increased from pre-WNS to post-WNS years. Activity levels of hoary bats Lasiurus cinereus significantly declined between pre- and post-WNS years. As a nonhibernating, migratory species, hoary bat declines might be correlated with wind-energy development impacts occurring in the same time frame rather than WNS. Intraseason activity patterns also were affected by WNS, though the results were highly variable among species. Little brown bats showed an overall increase in activity from early to late summer pre-WNS, presumably due to detections of newly volant young added to the local population. However, the opposite occurred post-WNS, indicating that reproduction among surviving little brown bats may be declining. Our data suggest that acoustical monitoring during the summer season can provide insights into species' relative abundance on the

  1. Spatio-temporal patterns of forest fires: a comprehensive application of the K-function

    NASA Astrophysics Data System (ADS)

    Tonini, Marj; Vega Orozco, Carmen; Kanevski, Mikhaïl; Conedera, Marco

    2013-04-01

    The spatial distribution of uncontrolled hazardous events, such as forest fires, is largely investigated from the scientific community with the purpose of finding out the more vulnerable areas. Mapping the location of spatio-temporal sequences for a given environmental dataset is of great impact; however, the majority of the studies miss the analysis of the aggregation over time. Nonetheless discovering unusual temporal pattern for a given time sequence is fundamental to understand the phenomena and underlying processes. The present study aims investigating both the spatial and the temporal cluster behaviour of forest fires occurrences registered in Canton Ticino (Switzerland) over a period of about 40 years and testing if space and time interact in generate clusters. To do this, the purely spatial, the time and the space-time extensions of the Ripley's K-function were applied. The Ripley's K-function is a statistic exploratory method which enables detecting whether or not a point process (e.g. the location of the ignition points) is randomly distributed. The purely spatial K-function K(r) is defined as the expected number of further events within an area of radius r around an arbitrary point of the pattern, divided by the intensity of the phenomenon. Under completely spatial randomness, the value of the K(r) is equal to the area around the point (=πr2), while observations above this theoretical value imply a clustering behaviour at the corresponding distance r. For the purely time analysis, the Ripley's K-function K(t) can be taught as a reformulation of the spatial version to detect unexpected aggregation of events over the temporal scale. For its computation, the value of the intensity used in K(r) is replaced by the total duration of the time sequence divided by the total number of observed events, and the distance r is replaced by the time interval t. Under time-regularity, K(t) equals 2t, whereas, observed measures above this theoretical value indicate a

  2. Spatial and Temporal Migration Patterns of Neotropical Migrants in the Southwest Revealed by Stable Isotopes

    USGS Publications Warehouse

    Paxton, Kristina L.; van Riper, Charles

    2006-01-01

    Executive Summary We used stable hydrogen isotopes (?D) to investigate both temporal and spatial patterns during spring migration for three warbler species, Wilson's Warbler (Wilsonia pusilla), MacGillivray's Warbler (Oporornis tolmiei), and Nashville Warbler (Vermivora ruficapilla), across multiple migration routes in southwest North America. A strong correlation between stable hydrogen isotope values of feathers and the local precipitation at sites where feathers where collected across the breeding range for all three species reaffirmed that stable hydrogen isotopes were a good predictor of breeding locations. For the Wilson's Warbler, we found a significant negative relationship between the date when warblers passed through the sampling station and ?D values of their feathers, indicating that warblers who bred the previous season at southern latitudes migrated through the migration stations earlier than did warblers that had previously bred at more northern latitudes. This pattern was consistent across their southwestern migration route (5 sites sampled) and was consistent between years. Comparing ?D values between migration stations also showed a shift towards more negative ?D values from the western to the eastern migration stations sampled in this study, which corresponded to different geographical regions of the Wilson's Warblers' western breeding range. For MacGillivray's Warbler we found the same temporal pattern as Wilson's Warbler, with warblers that bred the previous season at southern latitudes migrating through the migration stations earlier than warblers that had previously bred at more northern latitudes. This pattern was consistent at the Lower Colorado River and Arivaca Creek, the two sites where sample sizes were adequate to test these hypotheses. Comparison of the ?D between the two sites indicated that the majority of warblers migrating through these stations were breeding within a geographically limited area of MacGillivray's Warblers' overall

  3. Spatio-Temporal Patterns of Barmah Forest Virus Disease in Queensland, Australia

    PubMed Central

    Naish, Suchithra; Hu, Wenbiao; Mengersen, Kerrie; Tong, Shilu

    2011-01-01

    Background Barmah Forest virus (BFV) disease is a common and wide-spread mosquito-borne disease in Australia. This study investigated the spatio-temporal patterns of BFV disease in Queensland, Australia using geographical information system (GIS) tools and geostatistical analysis. Methods/Principal Findings We calculated the incidence rates and standardised incidence rates of BFV disease. Moran's I statistic was used to assess the spatial autocorrelation of BFV incidences. Spatial dynamics of BFV disease was examined using semi-variogram analysis. Interpolation techniques were applied to visualise and display the spatial distribution of BFV disease in statistical local areas (SLAs) throughout Queensland. Mapping of BFV disease by SLAs reveals the presence of substantial spatio-temporal variation over time. Statistically significant differences in BFV incidence rates were identified among age groups (χ2 = 7587, df = 7327,p<0.01). There was a significant positive spatial autocorrelation of BFV incidence for all four periods, with the Moran's I statistic ranging from 0.1506 to 0.2901 (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 state. Conclusions/Significance This is the first study to examine spatial and temporal variation in the incidence rates of BFV disease across Queensland using GIS and geostatistics. The BFV transmission varied with age and gender, which may be due to exposure rates or behavioural risk factors. There are differences in the spatio-temporal patterns of BFV disease which may be related to local socio-ecological and environmental factors. These research findings may have implications in the BFV disease control and prevention programs in Queensland. PMID:22022430

  4. Discovery of temporal and disease association patterns in condition-specific hospital utilization rates

    PubMed Central

    Haimovich, Julian S.; Venkatesh, Arjun K.; Coppi, Andreas; Li, Shu-Xia; Krumholz, Harlan M.

    2017-01-01

    Identifying temporal variation in hospitalization rates may provide insights about disease patterns and thereby inform research, policy, and clinical care. However, the majority of medical conditions have not been studied for their potential seasonal variation. The objective of this study was to apply a data-driven approach to characterize temporal variation in condition-specific hospitalizations. Using a dataset of 34 million inpatient discharges gathered from hospitals in New York State from 2008–2011, we grouped all discharges into 263 clinical conditions based on the principal discharge diagnosis using Clinical Classification Software in order to mitigate the limitation that administrative claims data reflect clinical conditions to varying specificity. After applying Seasonal-Trend Decomposition by LOESS, we estimated the periodicity of the seasonal component using spectral analysis and applied harmonic regression to calculate the amplitude and phase of the condition’s seasonal utilization pattern. We also introduced four new indices of temporal variation: mean oscillation width, seasonal coefficient, trend coefficient, and linearity of the trend. Finally, K-means clustering was used to group conditions across these four indices to identify common temporal variation patterns. Of all 263 clinical conditions considered, 164 demonstrated statistically significant seasonality. Notably, we identified conditions for which seasonal variation has not been previously described such as ovarian cancer, tuberculosis, and schizophrenia. Clustering analysis yielded three distinct groups of conditions based on multiple measures of seasonal variation. Our study was limited to New York State and results may not directly apply to other regions with distinct climates and health burden. A substantial proportion of medical conditions, larger than previously described, exhibit seasonal variation in hospital utilization. Moreover, the application of clustering tools yields groups

  5. Temporal organization of an anuran acoustic community in a Taiwanese subtropical forest

    USGS Publications Warehouse

    Hsu, M.-Y.; Kam, Y.-C.; Fellers, G.M.

    2006-01-01

    We recorded anuran vocalizations in each of four habitats at Lien Hua Chih Field Station, Taiwan, between July 2000 and July 2001. For each 27 biweekly sample, eight recorders taped calls for 1 min out of every 11 between the hours of 17:00 and 07:00. We obtained 11 481 recordings with calls, and identified 21 503 frogs or groups of frogs. These included 20 species, with an average of 10.4??3.5 species calling each night. Some species called year round, others called in the spring and summer, and a third group called only in the fall and winter. The number of species calling and the maximum calling intensity were correlated with both rainfall and air temperature. The nightly pattern of calling varied among species. Most species called continuously throughout the night, whereas some had a peak right after dusk. A few species had different nightly calling patterns in different habitats. Both Rana limnocharis and Rana kuhlii changed their calling pattern in the presence of large choruses of other anuran species. ?? 2006 The Authors.

  6. Mining and analysing spatio-temporal patterns of gene expression in an integrative database framework.

    PubMed

    Belmamoune, M; Potikanond, D; Verbeek, F J

    2010-03-25

    Mining patterns of gene expression provides a crucial approach in discovering knowledge such as finding genetic networks that underpin the embryonic development. Analysis of mining results and evaluation of their relevance in the domain remains a major concern. In this paper we describe our explorative studies in support of solutions to facilitate the analysis and interpretation of mining results. In our particular case we describe a solution that is found in the extension of the Gene Expression Management System (GEMS), i.e. an integrative framework for spatio-temporal organization of gene expression patterns of zebrafish to a framework supporting data mining, data analysis and patterns interpretation As a proof of principle, the GEMS has been equipped with data mining functionality suitable for spatio-temporal tracking, thereby generating added value to the submission of data for data mining and analysis. The analysis of the genetic networks is based on the availability of domain ontologies which dynamically provides meaning to the discovered patterns of gene expression data. Combination of data mining with the already presently available capabilities of GEMS will significantly augment current data processing and functional analysis strategies.

  7. Defining spatial and temporal patterns of phylogeographic structure in Madagascar's iguanid lizards (genus Oplurus).

    PubMed

    Chan, Lauren M; Choi, Dean; Raselimanana, Achille P; Rakotondravony, Hery A; Yoder, Anne D

    2012-08-01

    Understanding the remarkably high species diversity and levels of endemism found among Madagascar's flora and fauna has been the focus of many studies. One hypothesis that has received much attention proposes that Quaternary climate fluctuations spurred diversification. While spatial patterns of distribution and phylogenetic relationships can provide support for biogeographic predictions, temporal estimates of divergence are required to determine the fit of these geospatial patterns to climatic or biogeographic mechanisms. We use multilocus DNA sequence data to test whether divergence times among Malagasy iguanid lizards of the subfamily Oplurinae are compatible with a hypotheses of Pliocene-Pleistocene diversification. We estimate the oplurine species tree and associated divergence times under a relaxed-clock model. In addition, we examine the phylogeographic structure and population divergence times within two sister species of Oplurus primarily distributed in the north-west and south-west of Madagascar (Oplurus cuvieri and Oplurus cyclurus, respectively). We find that divergence events among oplurine lineages occurred in the Oligocene and Miocene and are thus far older and incompatible with the hypothesis that recent climate fluctuations are related to current species diversity. However, the timing of intraspecific divergences and spatial patterns of population genetic structure within O. cuvieri and O. cyclurus suggest a role for both intrinsic barriers and recent climate fluctuations at population-level divergences. Integrating information across spatial and temporal scales allows us to identify and better understand the mechanisms generating patterns diversity.

  8. Temporal Patterns in Bacterioplankton Community Composition in Three Reservoirs of Similar Trophic Status in Shenzhen, China

    PubMed Central

    Li, Jiancheng; Chen, Cheng; Lu, Jun; Lei, Anping; Hu, Zhangli

    2016-01-01

    The bacterioplankton community composition’s (BCC) spatial and temporal variation patterns in three reservoirs (Shiyan, Xikeng, and LuoTian Reservoir) of similar trophic status in Bao’an District, Shenzhen (China), were investigated using PCR amplification of the 16S rDNA gene and the denaturing gradient gel electrophoresis (DGGE) techniques. Water samples were collected monthly in each reservoir during 12 consecutive months. Distinct differences were detected in band number, pattern, and density of DGGE at different sampling sites and time points. Analysis of the DGGE fingerprints showed that changes in the bacterial community structure mainly varied with seasons, and the patterns of change indicated that seasonal forces might have a more significant impact on the BCC than eutrophic status in the reservoirs, despite the similar Shannon-Weiner index among the three reservoirs. The sequences obtained from excised bands were affiliated with Cyanobacteria, Firmicutes, Bacteriodetes, Acidobacteria, Actinobacteria, Planctomycetes, and Proteobacteria. PMID:27322295

  9. Judgments relative to patterns: how temporal sequence patterns affect judgments and memory.

    PubMed

    Kusev, Petko; Ayton, Peter; van Schaik, Paul; Tsaneva-Atanasova, Krasimira; Stewart, Neil; Chater, Nick

    2011-12-01

    Six experiments studied relative frequency judgment and recall of sequentially presented items drawn from 2 distinct categories (i.e., city and animal). The experiments show that judged frequencies of categories of sequentially encountered stimuli are affected by certain properties of the sequence configuration. We found (a) a first-run effect whereby people overestimated the frequency of a given category when that category was the first repeated category to occur in the sequence and (b) a dissociation between judgments and recall; respondents may judge 1 event more likely than the other and yet recall more instances of the latter. Specifically, the distribution of recalled items does not correspond to the frequency estimates for the event categories, indicating that participants do not make frequency judgments by sampling their memory for individual items as implied by other accounts such as the availability heuristic (Tversky & Kahneman, 1973) and the availability process model (Hastie & Park, 1986). We interpret these findings as reflecting the operation of a judgment heuristic sensitive to sequential patterns and offer an account for the relationship between memory and judged frequencies of sequentially encountered stimuli.

  10. 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.

  11. Decoding of retinal ganglion cell spike trains evoked by temporally patterned electrical stimulation.

    PubMed

    Ryu, Sang Baek; Ye, Jang Hee; Goo, Yong Sook; Kim, Chi Hyun; Kim, Kyung Hwan

    2010-08-12

    For successful restoration of vision by retinal prostheses, the neural activity of retinal ganglion cells (RGCs) evoked by electrical stimulation should represent the information of spatiotemporal patterns of visual input. We propose a method to evaluate the effectiveness of stimulation pulse trains so that the crucial temporal information of a visual input is accurately represented in the RGC responses as the amplitudes of pulse trains are modulated according to the light intensity. This was enabled by spike train decoding. The effectiveness of the stimulation was evaluated by the accuracy of decoding pulse amplitude from the RGC spike train, i.e., by the similarity between the original and the decoded pulse amplitude time series. When the parameters of stimulation were suitably determined, the RGC responses were reliably modulated by varying the amplitude of electrical pulses. Accordingly, the temporal pattern of pulse amplitudes could be successfully decoded from multiunit RGC spike trains. The range of pulse amplitude and the pulse rate were critical for accurate representation of input information in RGC responses. These results suggest that pulse amplitude modulation is a feasible means to encode temporal visual information by RGC spike trains and thus to implement stimulus encoding strategies for retinal prostheses.

  12. Microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks

    NASA Astrophysics Data System (ADS)

    Kerner, Boris S.; Klenov, Sergey L.

    2003-09-01

    A microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks due to on-ramps, merge bottlenecks (a reduction of highway lanes), and off-ramps is presented. The basic postulate of three-phase traffic theory is used, which claims that homogeneous (in space and time) model solutions (steady states) of synchronized flow cover a two dimensional region in the flow-density plane [B. S. Kerner, Phys. Rev. Lett. 81, 3797 (1998); Trans. Res. Rec. 1678, 160 (1999)]. Phase transitions leading to diverse congested patterns, pattern evolution, and pattern nonlinear features have been found. Diagrams of congested patterns, i.e., regions of the pattern emergence dependent on traffic demand, have been derived. Diverse effects of metastability with respect to the pattern formation have been found. The microscopic theory allows us to explain the main empirical pattern features at on-ramps and off-ramps which have recently been found [B. S. Kerner, Phys. Rev. E 65, 046138 (2002)]. (i) Rather than moving jams, synchronized flow first occurs at bottlenecks if the flow rate is slowly increasing. Wide moving jams can spontaneously occur only in synchronized flow. (ii) General patterns (GP) and synchronized flow patterns (SP) can spontaneously emerge at the bottlenecks. There can be the widening SP (WSP), the moving SP (MSP), and the localized SP. (iii) At on-ramps cases of “weak” and “strong” congestion should be distinguished. In contrast to weak congestion, under strong congestion the flow rate in synchronized flow in GP reaches a limit flow rate, the frequency of the moving jam emergence reaches a maximum, i.e., the GP characteristics under strong congestion do not depend on traffic demand. (iv) At the off-ramp GP with weak congestion occur. (v) A study of the pattern formation on a highway with two bottlenecks shows that diverse expanded patterns can occur, which cover both bottlenecks. SP first emerged at the downstream bottleneck can be caught

  13. Microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks.

    PubMed

    Kerner, Boris S; Klenov, Sergey L

    2003-09-01

    A microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks due to on-ramps, merge bottlenecks (a reduction of highway lanes), and off-ramps is presented. The basic postulate of three-phase traffic theory is used, which claims that homogeneous (in space and time) model solutions (steady states) of synchronized flow cover a two dimensional region in the flow-density plane [B. S. Kerner, Phys. Rev. Lett. 81, 3797 (1998); Trans. Res. Rec. 1678, 160 (1999)]. Phase transitions leading to diverse congested patterns, pattern evolution, and pattern nonlinear features have been found. Diagrams of congested patterns, i.e., regions of the pattern emergence dependent on traffic demand, have been derived. Diverse effects of metastability with respect to the pattern formation have been found. The microscopic theory allows us to explain the main empirical pattern features at on-ramps and off-ramps which have recently been found [B. S. Kerner, Phys. Rev. E 65, 046138 (2002)]. (i) Rather than moving jams, synchronized flow first occurs at bottlenecks if the flow rate is slowly increasing. Wide moving jams can spontaneously occur only in synchronized flow. (ii) General patterns (GP) and synchronized flow patterns (SP) can spontaneously emerge at the bottlenecks. There can be the widening SP (WSP), the moving SP (MSP), and the localized SP. (iii) At on-ramps cases of "weak" and "strong" congestion should be distinguished. In contrast to weak congestion, under strong congestion the flow rate in synchronized flow in GP reaches a limit flow rate, the frequency of the moving jam emergence reaches a maximum, i.e., the GP characteristics under strong congestion do not depend on traffic demand. (iv) At the off-ramp GP with weak congestion occur. (v) A study of the pattern formation on a highway with two bottlenecks shows that diverse expanded patterns can occur, which cover both bottlenecks. SP first emerged at the downstream bottleneck can be caught at the

  14. Patterns of acoustic variation in Cicada barbara Stål (Hemiptera, Cicadoidea) from the Iberian Peninsula and Morocco.

    PubMed

    Pinto-Juma, G A; Seabra, S G; Quartau, J A

    2008-02-01

    Field recordings of the calling song and of an amplitude modulated signal produced by males of Cicada barbara from North Africa and the Iberian Peninsula were analysed in order to assess the geographical acoustic variation and the potential usefulness of acoustic data in the discrimination of subspecies and populations. Sound recordings were digitized and the frequency and temporal properties of the calls of each cicada were analysed. In all regions studied, peak frequency, quartiles 25, 50 and 75% and syllable rate showed low coefficients of variation suggesting inherent static properties. All frequency variables were correlated with the latitude, decreasing from south to north. In addition, most acoustic variables of the calling song showed significant differences between regions, and PCA and DFA analyses supported a partitioning within this species between Iberian Peninsula+Ceuta and Morocco, corroborating mtDNA data on the same species. Therefore, the subspecific division of C. barbara into C. barbara barbara from Morocco and C. barbara lusitanica from Portugal, Spain and Ceuta finds support from the present acoustic analyses, a result which is also reinforced by molecular markers.

  15. Temporal phase-unwrapping algorithm for dynamic interference pattern analysis in interference-contrast microscopy.

    PubMed

    van den Doel, L R; van Vliet, L J

    2001-09-01

    A temporal phase-unwrapping algorithm has been developed for the analysis of dynamic interference patterns generated with interference-contrast microscopy in micromachined picoliter vials. These vials are etched in silicon dioxide, have a typical depth of 6 mum, and are filled with a liquid sample. In this kind of microscopy, fringe patterns are observed at the air-liquid interface. These fringe patterns are caused by interference between the directly reflected part of an incident plane wave and the part of that wave that is reflected on the bottom of the vial. The optical path difference (OPD) between both parts is proportional to the distance to the reflecting bottom of the vial. Evaporation decreases the OPD at the meniscus level and causes alternating constructive and destructive interference of the incident light, resulting in an interferogram. Imaging of the space-varying OPD yields a fringe pattern in which the isophotes correspond to isoheight curves of the meniscus. When the bottom is flat, the interference pattern allows for monitoring of the meniscus as a function of time during evaporation. However, when there are objects on the bottom of the vial, the heights of these objects are observed as phase jumps in the fringes proportional to their heights. First, we present a classical electromagnetic description of interference-contrast microscopy. Second, a temporal phase-unwrapping algorithm is described that retrieves the meniscus profile from the interference pattern. Finally, this algorithm is applied to measure height differences of objects on the bottom in other micromachined vials with a precision of ~5 nm.

  16. Deciphering principles of morphogenesis from temporal and spatial patterns on the integument

    PubMed Central

    Li, Ang; Lai, Yung-Chih; Figueroa, Seth; Yang, Tian; Widelitz, Randall B; Kobielak, Krzysztof; Nie, Qing; Chuong, Cheng Ming

    2015-01-01

    How tissue patterns form in development and regeneration is a fundamental issue remaining to be fully understood. The integument often forms repetitive units in space (periodic patterning) and time (cyclic renewal), such as feathers and hairs. Integument patterns are visible and experimentally manipulatable, helping us reveal pattern formative processes. Variability is seen in regional phenotypic specificities and temporal cycling at different physiological stages. Here we show some cellular / molecular bases revealed by analyzing integument patterns. 1) Localized cellular activity (proliferation, rearrangement, apoptosis, differentiation) transforms prototypic organ primordia into specific shapes. Combinatorial positioning of different localized activity zones generates diverse and complex organ forms. 2) Competitive equilibrium between activators and inhibitors regulates stem cells through cyclic quiescence and activation. Dynamic interactions between stem cells and their adjacent niche regulate regenerative behavior, modulated by multi-layers of macro-environmental factors (dermis, body hormone status and external environment). Genomics studies may reveal how positional information of localized cellular activity is stored. In vivo skin imaging and lineage tracing unveils new insights into stem cell plasticity. Principles of self-assembly obtained from the integumentary organ model can be applied to help restore damaged patterns during regenerative wound healing and for tissue engineering to rebuild tissues. PMID:25858668

  17. Exploring Spatio-temporal Dynamics of Cellular Automata for Pattern Recognition in Networks.

    PubMed

    Miranda, Gisele Helena Barboni; Machicao, Jeaneth; Bruno, Odemir Martinez

    2016-11-22

    Network science is an interdisciplinary field which provides an integrative approach for the study of complex systems. In recent years, network modeling has been used for the study of emergent phenomena in many real-world applications. Pattern recognition in networks has been drawing attention to the importance of network characterization, which may lead to understanding the topological properties that are related to the network model. In this paper, the Life-Like Network Automata (LLNA) method is introduced, which was designed for pattern recognition in networks. LLNA uses the network topology as a tessellation of Cellular Automata (CA), whose dynamics produces a spatio-temporal pattern used to extract the feature vector for network characterization. The method was evaluated using synthetic and real-world networks. In the latter, three pattern recognition applications were used: (i) identifying organisms from distinct domains of life through their metabolic networks, (ii) identifying online social networks and (iii) classifying stomata distribution patterns varying according to different lighting conditions. LLNA was compared to structural measurements and surpasses them in real-world applications, achieving improvement in the classification rate as high as 23%, 4% and 7% respectively. Therefore, the proposed method is a good choice for pattern recognition applications using networks and demonstrates potential for general applicability.

  18. Exploring Spatio-temporal Dynamics of Cellular Automata for Pattern Recognition in Networks

    NASA Astrophysics Data System (ADS)

    Miranda, Gisele Helena Barboni; Machicao, Jeaneth; Bruno, Odemir Martinez

    2016-11-01

    Network science is an interdisciplinary field which provides an integrative approach for the study of complex systems. In recent years, network modeling has been used for the study of emergent phenomena in many real-world applications. Pattern recognition in networks has been drawing attention to the importance of network characterization, which may lead to understanding the topological properties that are related to the network model. In this paper, the Life-Like Network Automata (LLNA) method is introduced, which was designed for pattern recognition in networks. LLNA uses the network topology as a tessellation of Cellular Automata (CA), whose dynamics produces a spatio-temporal pattern used to extract the feature vector for network characterization. The method was evaluated using synthetic and real-world networks. In the latter, three pattern recognition applications were used: (i) identifying organisms from distinct domains of life through their metabolic networks, (ii) identifying online social networks and (iii) classifying stomata distribution patterns varying according to different lighting conditions. LLNA was compared to structural measurements and surpasses them in real-world applications, achieving improvement in the classification rate as high as 23%, 4% and 7% respectively. Therefore, the proposed method is a good choice for pattern recognition applications using networks and demonstrates potential for general applicability.

  19. Exploring Spatio-temporal Dynamics of Cellular Automata for Pattern Recognition in Networks

    PubMed Central

    Miranda, Gisele Helena Barboni; Machicao, Jeaneth; Bruno, Odemir Martinez

    2016-01-01

    Network science is an interdisciplinary field which provides an integrative approach for the study of complex systems. In recent years, network modeling has been used for the study of emergent phenomena in many real-world applications. Pattern recognition in networks has been drawing attention to the importance of network characterization, which may lead to understanding the topological properties that are related to the network model. In this paper, the Life-Like Network Automata (LLNA) method is introduced, which was designed for pattern recognition in networks. LLNA uses the network topology as a tessellation of Cellular Automata (CA), whose dynamics produces a spatio-temporal pattern used to extract the feature vector for network characterization. The method was evaluated using synthetic and real-world networks. In the latter, three pattern recognition applications were used: (i) identifying organisms from distinct domains of life through their metabolic networks, (ii) identifying online social networks and (iii) classifying stomata distribution patterns varying according to different lighting conditions. LLNA was compared to structural measurements and surpasses them in real-world applications, achieving improvement in the classification rate as high as 23%, 4% and 7% respectively. Therefore, the proposed method is a good choice for pattern recognition applications using networks and demonstrates potential for general applicability. PMID:27874024

  20. Similarity breeds proximity: Pattern similarity within and across contexts is related to later mnemonic judgments of temporal proximity

    PubMed Central

    Ezzyat, Youssef; Davachi, Lila

    2014-01-01

    Summary Experiences unfold over time, but little is known about the mechanisms that support the formation of coherent episodic memories for temporally-extended events. Recent work in animals has provided evidence for signals in hippocampus that could link events across temporal gaps, however it is unknown whether and how such signals might be related to later memory for temporal information in humans. We measured patterns of fMRI BOLD activity as people encoded items that were separated in time and manipulated the presence of shared or distinct context across items. We found that hippocampal pattern similarity in the BOLD response across trials predicted later temporal memory decisions when context changed. By contrast, pattern similarity in lateral occipital cortex was related to memory only when context remained stable. These data provide the first evidence in humans that representational stability in hippocampus across time may be a mechanism for temporal memory organization. PMID:24607235

  1. Diverse spatio-temporal dynamical patterns of p53 and cell fate decisions

    NASA Astrophysics Data System (ADS)

    Clairambault, Jean; Eliaš, Ján

    2016-06-01

    The protein p53 as a tumour suppressor protein accumulates in cells in response to DNA damage and transactivates a large variety of genes involved in apoptosis, cell cycle regulation and numerous other processes. Recent biological observations suggest that specific spatio-temporal dynamical patterns of p53 may be associated with specific cellular response, and thus the spatio-temporal heterogeneity of the p53 dynamics contributes to the overall complexity of p53 signalling. Reaction-diffusion equations taking into account spatial representation of the cell and motion of the species inside the cell can be used to model p53 protein network and could be thus of some help to biologists and pharmacologists in anticancer treatment.

  2. Meteor tracking via local pattern clustering in spatio-temporal domain

    NASA Astrophysics Data System (ADS)

    Kukal, Jaromír.; Klimt, Martin; Švihlík, Jan; Fliegel, Karel

    2016-09-01

    Reliable meteor detection is one of the crucial disciplines in astronomy. A variety of imaging systems is used for meteor path reconstruction. The traditional approach is based on analysis of 2D image sequences obtained from a double station video observation system. Precise localization of meteor path is difficult due to atmospheric turbulence and other factors causing spatio-temporal fluctuations of the image background. The proposed technique performs non-linear preprocessing of image intensity using Box-Cox transform as recommended in our previous work. Both symmetric and asymmetric spatio-temporal differences are designed to be robust in the statistical sense. Resulting local patterns are processed by data whitening technique and obtained vectors are classified via cluster analysis and Self-Organized Map (SOM).

  3. Spatial pattern of reference evapotranspiration change and its temporal evolution over Southwest China

    NASA Astrophysics Data System (ADS)

    Sun, Shanlei; Wang, Guojie; Huang, Jin; Mu, Mengyuan; Yan, Guixia; Liu, Chunwei; Gao, Chujie; Li, Xing; Yin, Yixing; Zhang, Fangmin; Zhu, Siguang; Hua, Wenjian

    2016-09-01

    Due to the close relationship of climate change with reference evapotranspiration (ETo), detecting changes in ETo spatial distribution and its temporal evolution at local and regional levels is favorable to comprehensively understand climate change-induced impacts on hydrology and agriculture. In this study, the objective is to identify whether climate change has caused variation of ETo spatial distribution in different analysis periods [i.e., long- (20-year), medium- (10-year), and short-term (5-year)] and to investigate its temporal evolution (namely, when these changes happened) at annual and monthly scales in Southwest China (SWC). First, we estimated ETo values using the United Nations Food and Agriculture Organization (FAO) Penman-Monteith equation, based on historical climate data measured at 269 weather sites during 1973-2012. The analysis of variance (ANOVA) results indicated that the spatial pattern of annual ETo had significantly changed during the past 40 years, particularly in west SWC for the long-term analysis period, and west and southeast SWC in both medium- and short-term periods, which corresponded to the percent area of significant differences which were 21.9, 58.0, and 48.2 %, respectively. For investigating temporal evolution of spatial patterns of annual ETo, Duncan's multiple range test was used, and we found that the most significant changes appeared during 1988-2002 with the significant area of higher than 25.0 %. In addition, for long-, medium-, and short-term analysis periods, the spatial distribution has significantly changed during March, September, November, and December, especially in the corresponding periods of 1988-1997, 1983-1992, 1973-1977, and 1988-2002. All in all, climate change has resulted in significant ETo changes in SWC since the 1970s. Knowledge of climate change-induced spatial distribution of ETo and its temporal evolution would aid in formulating strategies for water resources and agricultural managements.

  4. Geographic Variation in Daily Temporal Activity Patterns of a Neotropical Marsupial (Gracilinanus agilis).

    PubMed

    Vieira, Emerson M; de Camargo, Nícholas F; Colas, Paul F; Ribeiro, Juliana F; Cruz-Neto, Ariovaldo P

    2017-01-01

    The temporal activity of animals is an outcome of both biotic and abiotic factors, which may vary along the geographic range of the species. Therefore, studies conducted with a species in different localities with distinct features could elucidate how animals deal with such factors. In this study, we used live traps equipped with timing devices to investigate the temporal activity patterns of the didelphid Gracilinanus agilis in two dry-woodland areas of the Brazilian savanna (Cerrado). These areas were located about 660 km apart, one in Central Brazil and the other in Southeastern Brazil. We compared such patterns considering both reproductive and non-reproductive periods, and how it varies as a function of temperature on a seasonal basis. In Central Brazil, we found a constant, and temperature-independent activity during the night in both reproductive and non-reproductive periods. On the other hand, in Southeastern Brazil, we detected a constant activity during the reproductive period, but in the non-reproductive period G. agilis presented a peak of activity between two and four hours after sunset. Moreover, in this latter we found a relation between temporal activity and temperature during the autumn and spring. These differences in temporal activity between areas, observed during the non-reproductive period, might be associated with the higher seasonal variability in temperature, and lower mean temperatures in the Southeastern site in comparison to the Central one. In Southeastern Brazil, the decrease in temperature during the non-reproductive season possibly forced G. agilis to be active only at certain hours of the night. However, likely due to the reproductive activities (intensive foraging and searching for mates) this marsupial showed constant, temperature-independent activity during the night in the reproductive period at both sites.

  5. Geographic Variation in Daily Temporal Activity Patterns of a Neotropical Marsupial (Gracilinanus agilis)

    PubMed Central

    Vieira, Emerson M.; de Camargo, Nícholas F.; Colas, Paul F.; Ribeiro, Juliana F.; Cruz-Neto, Ariovaldo P.

    2017-01-01

    The temporal activity of animals is an outcome of both biotic and abiotic factors, which may vary along the geographic range of the species. Therefore, studies conducted with a species in different localities with distinct features could elucidate how animals deal with such factors. In this study, we used live traps equipped with timing devices to investigate the temporal activity patterns of the didelphid Gracilinanus agilis in two dry-woodland areas of the Brazilian savanna (Cerrado). These areas were located about 660 km apart, one in Central Brazil and the other in Southeastern Brazil. We compared such patterns considering both reproductive and non-reproductive periods, and how it varies as a function of temperature on a seasonal basis. In Central Brazil, we found a constant, and temperature-independent activity during the night in both reproductive and non-reproductive periods. On the other hand, in Southeastern Brazil, we detected a constant activity during the reproductive period, but in the non-reproductive period G. agilis presented a peak of activity between two and four hours after sunset. Moreover, in this latter we found a relation between temporal activity and temperature during the autumn and spring. These differences in temporal activity between areas, observed during the non-reproductive period, might be associated with the higher seasonal variability in temperature, and lower mean temperatures in the Southeastern site in comparison to the Central one. In Southeastern Brazil, the decrease in temperature during the non-reproductive season possibly forced G. agilis to be active only at certain hours of the night. However, likely due to the reproductive activities (intensive foraging and searching for mates) this marsupial showed constant, temperature-independent activity during the night in the reproductive period at both sites. PMID:28052077

  6. 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

  7. Spatial and temporal patterns of carbon storage in forest ecosystems on Hainan island, southern China.

    PubMed

    Ren, Hai; Li, Linjun; Liu, Qiang; Wang, Xu; Li, Yide; Hui, Dafeng; Jian, Shuguang; Wang, Jun; Yang, Huai; Lu, Hongfang; Zhou, Guoyi; 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.

  8. Progressive tarsal patterning in the Drosophila by temporally dynamic regulation of transcription factor genes.

    PubMed

    Natori, Kohei; Tajiri, Reiko; Furukawa, Shiori; Kojima, Tetsuya

    2012-01-15

    The morphology of insect appendages, such as the number and proportion of leg tarsal segments, is immensely diverse. In Drosophila melanogaster, adult legs have five tarsal segments. Accumulating evidence indicates that tarsal segments are formed progressively through dynamic changes in the expression of transcription factor genes, such as Bar genes, during development. In this study, to examine further the basis of progressive tarsal patterning, the precise expression pattern and function of several transcription factor genes were investigated in relation to the temporal regulation of Bar expression. The results indicate that nubbin is expressed over a broad region at early stages but gradually disappears from the middle of the tarsal region. This causes the progressive expansion of rotund expression, which in turn progressively represses Bar expression, leading to the formation of the tarsal segment 3. The region corresponding to the tarsal segment 4 is formed when apterous expression is initiated, which renders Bar expression refractory to rotund. In addition, the tarsal segment 2 appears to be derived from the region that expresses Bar at a very early stage. Cessation of Bar expression in this region requires the function of spineless, which also regulates rotund expression. These findings indicate that the temporally dynamic regulatory interaction of these transcription factor genes is the fundamental basis of the progressive patterning of the tarsal region.

  9. Temporal changes of spatial soil moisture patterns: controlling factors explained with a multidisciplinary approach

    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

    2016-04-01

    Characterizing the spatial patterns of soil moisture is critical for hydrological and meteorological models, as soil moisture is a key variable that controls matter and energy fluxes and soil-vegetation-atmosphere exchange processes. Deriving detailed process understanding at the hillslope scale is not trivial, because of the temporal variability of local soil moisture dynamics. Nevertheless, it remains a challenge to provide adequate information on the temporal variability of soil moisture and its controlling factors. Recent advances in wireless sensor technology allow monitoring of soil moisture dynamics with high temporal resolution at varying scales. In addition, 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, as being related to soil apparent electrical conductivity (ECa). The objective of this study was to characterize the spatial and temporal pattern of soil moisture at the hillslope scale and to 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 a wireless soil moisture monitoring network. For a hillslope site within the Schäfertal catchment (Central Germany), soil water dynamics were observed during 14 months, and soil ECa was mapped on seven occasions whithin this period of time using an EM38-DD device. Using the Spearman rank correlation coefficient, we described the temporal persistence of a dry and a wet characteristic state of soil moisture as well as the switching mechanisms, inferring the local properties that control the observed spatial patterns and the hydrological processes driving the transitions. Based on this, we evaluated the use of EMI for mapping the spatial pattern of soil moisture under

  10. Different patterns of famous people recognition disorders in patients with right and left anterior temporal lesions: a systematic review.

    PubMed

    Gainotti, Guido

    2007-04-09

    Selective disorders in recognition of familiar people have been described in patients with right and left anterior temporal lesions, but the exact nature of these cognitive impairments remains controversial. A clarification of this issue could have theoretical implications, because, according to Snowden et al. [Snowden, J. S., Thompson, J. C., & Neary, D. (2004). Knowledge of famous faces and names in semantic dementia. Brain, 127, 860-872], the pattern of impairment shown by patients with right and left anterior temporal atrophy is inconsistent with unitary, abstract, amodal models of semantic memory. This pattern could, on the contrary suggest a multimodal network, in which the right and left temporal lobes would mainly process and store visual and, respectively, verbal information. I tried to clarify this issue by systematically reviewing: (a) all published individual cases of patients showing a prevalent damage of the anterior parts of the right or left temporal lobes and a selective disorder of famous people recognition; (b) all group studies of patients with right or left temporal lobe epilepsy, which had investigated aspects of famous people recognition impairment. Results of these reviews consistently showed that different patterns of impaired recognition of familiar people can be observed in patients with right and left anterior temporal pathology. These patterns consist of a loss of familiarity feelings and of person specific information retrieval from face stimuli, when the right temporal lobe is damaged and of a prevalent impairment in finding their names when the anterior parts of the left temporal lobe are selectively damaged.

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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 during their pluri-annual migration in the Northern Atlantic. Through an analytical approach based on the animal's own motion (independent of currents) and diving behavior distinct zones of high and low foraging success were identified. High foraging success occurred in a sub-equatorial zone spanning the width of the Atlantic and at high (>30°N) latitudes. Between these zones in the centre of North Atlantic gyre there was low foraging success. This "ocean desert" area was traversed at high speed by leatherbacks on their way to more productive areas at higher latitudes. Animals traveled slowly in high foraging success areas and dived shallower (17.2 ± 8.0 km day - 1 and 53.6 ± 33.1 m mean ± SD respectively) than in low foraging success areas (51.0 ± 13.1 km day - 1 and 81.8 ± 56.2 m mean ± SD respectively). These spatio-temporal foraging patterns seem to relatively closely match the main features of the integrated meso-zooplankton distribution in the North Atlantic. Our method of defining high foraging success areas is intuitive and relatively easy to implement but also takes into account the impact of oceanic currents on animal's behavior.

  12. Temporal and geographic patterns of Aedes aegypti (Diptera: Culicidae) production in Iquitos, Peru.

    PubMed

    Morrison, Amy C; Gray, Kenneth; Getis, Arthur; Astete, Helvio; Sihuincha, Moises; Focks, Dana; Watts, Douglas; Stancil, Jeffrey D; Olson, James G; Blair, Patrick; Scott, Thomas W

    2004-11-01

    Large-scale longitudinal cohort studies are necessary to characterize temporal and geographic variation in Aedes aegypti (L.) (Diptera: Culicidae) production patterns and to develop targeted dengue control strategies that will reduce disease. We carried out pupal/demographic surveys in a circuit of approximately 6,000 houses, 10 separate times, between January 1999 and August 2002 in the Amazonian city of Iquitos, Peru. We quantified the number of containers positive for Ae. aegypti larvae and/or pupae, containers holding pupae, and the absolute number of pupae by 4-mo sampling circuits and spatially by geographic area by using a geographic information system developed for the city. A total of 289,941 water-holding containers were characterized, of which 7.3% were positive for Ae. aegypti. Temporal and geographic variations were detected for all variables examined, and the relative importance of different container types for production of Ae. aegypti was calculated. Ae. aegypti larvae and pupae were detected in 64 types of containers. Consistent production patterns were observed for the lid status (lids: 32% wet containers, 2% pupal production), container location (outdoor: 43% wet containers, 85% pupal production), and method by which the container was filled with water (rain filled: 15% wet containers, 88.3% pupal production); these patterns were consistent temporally and geographically. We describe a new container category (nontraditional) that includes transient puddles, which were rare but capable of producing large numbers of pupae. Because of high variable pupal counts, four container categories (large tank, medium storage, miscellaneous, and nontraditional) should be targeted in addition to outdoor rain-filled containers that are not covered by a lid. The utility of targeted Ae. aegypti control is discussed, as well as the ability to achieve control objectives based on published but untested threshold values.

  13. Assessing Temporal and Spatial Patterns of Observed and Predicted Ozone in Multiple Urban Areas

    PubMed Central

    Simon, Heather; Wells, Benjamin; Baker, Kirk R.; Hubbell, Bryan

    2016-01-01

    Background: Ambient monitoring data show spatial gradients in ozone (O3) across urban areas. Nitrogen oxide (NOx) emissions reductions will likely alter these gradients. Epidemiological studies often use exposure surrogates that may not fully account for the impacts of spatially and temporally changing concentrations on population exposure. Objectives: We examined the impact of large NOx decreases on spatial and temporal O3 patterns and the implications on exposure. Methods: We used a photochemical model to estimate O3 response to large NOx reductions. We derived time series of 2006–2008 O3 concentrations consistent with 50% and 75% NOx emissions reduction scenarios in three urban areas (Atlanta, Philadelphia, and Chicago) at each monitor location and spatially interpolated O3 to census-tract centroids. Results: We predicted that low O3 concentrations would increase and high O3 concentrations would decrease in response to NOx reductions within an urban area. O3 increases occurred across larger areas for the seasonal mean metric than for the regulatory metric (annual 4th highest daily 8-hr maximum) and were located only in urban core areas. O3 always decreased outside the urban core (e.g., at locations of maximum local ozone concentration) for both metrics and decreased within the urban core in some instances. NOx reductions led to more uniform spatial gradients and diurnal and seasonal patterns and caused seasonal peaks in midrange O3 concentrations to shift from midsummer to earlier in the year. Conclusions: These changes have implications for how O3 exposure may change in response to NOx reductions and are informative for the design of future epidemiology studies and risk assessments. Citation: Simon H, Wells B, Baker KR, Hubbell B. 2016. Assessing temporal and spatial patterns of observed and predicted ozone in multiple urban areas. Environ Health Perspect 124:1443–1452; http://dx.doi.org/10.1289/EHP190 PMID:27153213

  14. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

  16. 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

  17. Trend and uncertainty in spatial-temporal patterns of hydrological droughts in the Amazon basin

    NASA Astrophysics Data System (ADS)

    Lopes, A. V.; Chiang, J. C. H.; Thompson, S. A.; Dracup, J. A.

    2016-04-01

    Spatial-temporal patterns of hydrological droughts in the Amazon basin are derived from drought indices computed from existing streamflow data. Principal component analysis and Monte Carlo simulations are employed to account for the uncertainty and overcome the limitations of missing data in streamflow records. Results show that northern and southern subbasins differ in drought trends and in patterns of correlation between drought indices and climate anomalies originating from the Pacific (El Niño-Southern Oscillation) and Atlantic (differences in sea surface temperature across the equator) Oceans. A significant trend toward more intense droughts is found in the southern subbasins, which is highly correlated to tropical Atlantic Ocean sea surface temperature anomalies. That drying trend might have distinct causes in each subbasin and can lead to potential intensification of regional impacts.

  18. Mechanisms for spatio-temporal pattern formation in highway traffic models.

    PubMed

    Wilson, R Eddie

    2008-06-13

    A key qualitative requirement for highway traffic models is the ability to replicate a type of traffic jam popularly referred to as a phantom jam, shock wave or stop-and-go wave. Despite over 50 years of modelling, the precise mechanisms for the generation and propagation of stop-and-go waves and the associated spatio-temporal patterns are in dispute. However, the increasing availability of empirical datasets, such as those collected from motorway incident detection and automatic signalling system (MIDAS) inductance loops in the UK or the next-generation simulation trajectory data (NGSIM) project in the USA, means that we can expect to resolve these questions definitively in the next few years. This paper will survey the essence of the competing explanations of highway traffic pattern formation and introduce and analyse a new mechanism, based on dynamical systems theory and bistability, which can help resolve the conflict.

  19. Spatio-temporal dynamics of the white-eye square superlattice pattern in dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Wei, Lingyan; Dong, Lifang; Feng, Jianyu; Liu, Weibo; Fan, Weili; Pan, Yuyang

    2016-05-01

    We report on the first investigation of the white-eye square superlattice pattern (WESSP) in a dielectric barrier discharge system. The evolution of patterns with increasing voltage is given. A phase diagram of WESSP as functions of gas pressure p and argon concentration φ is presented. The spatio-temporal dynamics of the WESSP is studied by using an intensified charge-coupled device camera and photomultipliers. Results show that the WESSP consists of four different transient sublattices, whose discharge sequence is small spots—spots on the line—halos—central spots in each half voltage cycle. The discharge moment and position of each sublattice are dependent upon the field of the wall charges produced by all sublattices discharged previously.

  20. 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.

  1. A framework for the assessment of the spatial and temporal patterns of threatened coastal delphinids

    PubMed Central

    Wang, Jingzhen; Yang, Yingting; Yang, Feng; Li, Yuelin; Li, Lianjie; Lin, Derun; He, Tangtian; Liang, Bo; Zhang, Tao; Lin, Yao; Li, Ping; Liu, Wenhua

    2016-01-01

    The massively accelerated biodiversity loss rate in the Anthropocene calls for an efficient and effective way to identify the spatial and temporal dynamics of endangered species. To this end, we developed a useful identification framework based on a case study of locally endangered Sousa chinensis by combining both LEK (local ecological knowledge) evaluation and regional boat-based survey methods. Our study investigated the basic ecological information of Sousa chinensis in the estuaries of eastern Guangdong that had previously been neglected, which could guide the future study and conservation. Based on the statistical testing of reported spatial and temporal dolphins sighting data from fishermen and the ecological monitoring analyses, including sighting rate, site fidelity and residence time estimations, some of the current Sousa chinensis units are likely to be geographically isolated and critically endangered, which calls for much greater conservation efforts. Given the accelerated population extinction rate and increasing budgetary constraints, our survey pattern can be applied in a timely and economically acceptable manner to the spatial and temporal assessment of other threatened coastal delphinids, particularly when population distributions are on a large scale and traditional sampling methods are difficult to implement. PMID:26804347

  2. A framework for the assessment of the spatial and temporal patterns of threatened coastal delphinids

    NASA Astrophysics Data System (ADS)

    Wang, Jingzhen; Yang, Yingting; Yang, Feng; Li, Yuelin; Li, Lianjie; Lin, Derun; He, Tangtian; Liang, Bo; Zhang, Tao; Lin, Yao; Li, Ping; Liu, Wenhua

    2016-01-01

    The massively accelerated biodiversity loss rate in the Anthropocene calls for an efficient and effective way to identify the spatial and temporal dynamics of endangered species. To this end, we developed a useful identification framework based on a case study of locally endangered Sousa chinensis by combining both LEK (local ecological knowledge) evaluation and regional boat-based survey methods. Our study investigated the basic ecological information of Sousa chinensis in the estuaries of eastern Guangdong that had previously been neglected, which could guide the future study and conservation. Based on the statistical testing of reported spatial and temporal dolphins sighting data from fishermen and the ecological monitoring analyses, including sighting rate, site fidelity and residence time estimations, some of the current Sousa chinensis units are likely to be geographically isolated and critically endangered, which calls for much greater conservation efforts. Given the accelerated population extinction rate and increasing budgetary constraints, our survey pattern can be applied in a timely and economically acceptable manner to the spatial and temporal assessment of other threatened coastal delphinids, particularly when population distributions are on a large scale and traditional sampling methods are difficult to implement.

  3. Dynamic evolving spiking neural networks for on-line spatio- and spectro-temporal pattern recognition.

    PubMed

    Kasabov, Nikola; Dhoble, Kshitij; Nuntalid, Nuttapod; Indiveri, Giacomo

    2013-05-01

    On-line learning and recognition of spatio- and spectro-temporal data (SSTD) is a very challenging task and an important one for the future development of autonomous machine learning systems with broad applications. Models based on spiking neural networks (SNN) have already proved their potential in capturing spatial and temporal data. One class of them, the evolving SNN (eSNN), uses a one-pass rank-order learning mechanism and a strategy to evolve a new spiking neuron and new connections to learn new patterns from incoming data. So far these networks have been mainly used for fast image and speech frame-based recognition. Alternative spike-time learning methods, such as Spike-Timing Dependent Plasticity (STDP) and its variant Spike Driven Synaptic Plasticity (SDSP), can also be used to learn spatio-temporal representations, but they usually require many iterations in an unsupervised or semi-supervised mode of learning. This paper introduces a new class of eSNN, dynamic eSNN, that utilise both rank-order learning and dynamic synapses to learn SSTD in a fast, on-line mode. The paper also introduces a new model called deSNN, that utilises rank-order learning and SDSP spike-time learning in unsupervised, supervised, or semi-supervised modes. The SDSP learning is used to evolve dynamically the network changing connection weights that capture spatio-temporal spike data clusters both during training and during recall. The new deSNN model is first illustrated on simple examples and then applied on two case study applications: (1) moving object recognition using address-event representation (AER) with data collected using a silicon retina device; (2) EEG SSTD recognition for brain-computer interfaces. The deSNN models resulted in a superior performance in terms of accuracy and speed when compared with other SNN models that use either rank-order or STDP learning. The reason is that the deSNN makes use of both the information contained in the order of the first input spikes

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

    USGS Publications Warehouse

    Ruetz, C. R.; 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

  5. Spatial and temporal patterns in modeled particle transport to estuarine habitat with comparisons to larval fish settlement patterns

    NASA Astrophysics Data System (ADS)

    Brown, C. A.; Jackson, G. A.; Holt, S. A.; Holt, G. J.

    2005-07-01

    Larval fish settlement in estuarine nursery areas is the end result of numerous biological and physical processes. We used a numerical circulation model coupled to a particle transport model to examine the role that physics play in determining settlement patterns of red drum larvae ( Sciaenops ocellatus) in nursery habitat along the Texas coast. We examined supply at various spatial scales (supply to inlet, bays, and individual settlement sites). Temporal patterns in larval settlement in Aransas Bay, Texas, are correlated with several indices of modeled particle supply (number of particles inside the bays, integrated particle input to Lydia Ann Channel, and cumulative number of competent particles in Lydia Ann Channel). High abundances of recently settled red drum in Aransas Bay result from a combination of high larval input, limited habitat for settlement, and proximity of habitat to the inlet. In contrast, larval settlement in Corpus Christi and Redfish Bays does not appear to be related to modeled measures of larval supply. Modeled particle supply at the bay-scale suggests that difference in the abundance of recently settled red drum between the bays may be related to larval supply normalized by the amount available settlement habitat within the bay.

  6. Associative neural network model for the generation of temporal patterns. Theory and application to central pattern generators.

    PubMed Central

    Kleinfeld, D; Sompolinsky, H

    1988-01-01

    Cyclic patterns of motor neuron activity are involved in the production of many rhythmic movements, such as walking, swimming, and scratching. These movements are controlled by neural circuits referred to as central pattern generators (CPGs). Some of these circuits function in the absence of both internal pacemakers and external feedback. We describe an associative neural network model whose dynamic behavior is similar to that of CPGs. The theory predicts the strength of all possible connections between pairs of neurons on the basis of the outputs of the CPG. It also allows the mean operating levels of the neurons to be deduced from the measured synaptic strengths between the pairs of neurons. We apply our theory to the CPG controlling escape swimming in the mollusk Tritonia diomedea. The basic rhythmic behavior is shown to be consistent with a simplified model that approximates neurons as threshold units and slow synaptic responses as elementary time delays. The model we describe may have relevance to other fixed action behaviors, as well as to the learning, recall, and recognition of temporally ordered information. Images FIGURE 2 FIGURE 4 PMID:3233265

  7. Spatial and temporal patterns of Ambystoma tigrinum virus (ATV) prevalence in tiger salamanders Ambystoma tigrinum nebulosum.

    PubMed

    Greer, Amy L; Brunner, Jesse L; Collins, James P

    2009-05-27

    Amphibian ranaviruses have been documented as causes of mass mortality in amphibian populations throughout the world. The temporal and spatial dynamics of ranavirus infections when epidemics are not apparent remains unclear. To address this question, we collected tissue samples from 2003 to 2006 in 4 geographically separated tiger salamander Ambystoma tigrinum nebulosum host populations on the Kaibab Plateau in northern Arizona. We tested for Ambystoma tigrinum virus (ATV), a lethal ranavirus of tiger salamanders, calculated ATV prevalence for each sampling date, and examined temporal and spatial patterns by quantifying the annual level of ATV synchrony among populations using the intraclass correlation coefficient. Salamander populations were commonly infected with ATV. We observed no morbidity or mortality in these populations even as ATV prevalence values varied from 0 to 57%. Infection prevalence across the landscape was more similar within a given year than between years. There was no statistically significant spatial pattern in prevalence across the landscape. Our findings highlight the need to explore new hypotheses regarding the population level impact of these pathogens on amphibian communities.

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

    PubMed

    Francuski, Lj; Matić, 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.

  9. 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.

  10. 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 ( ρ=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.

  11. Hyperpigmentation in North Sea dab Limanda limanda. I. Spatial and temporal patterns and host effects.

    PubMed

    Grütjen, F; Lang, T; Feist, S; Bruno, D; Noguera, P; Wosniok, W

    2013-03-13

    Hyperpigmentation is a term describing a specific pigment anomaly affecting common dab Limanda limanda in the North Sea and, less frequently, in adjacent areas, e.g. the English Channel, Irish and Celtic Seas, western Baltic Sea and Icelandic waters. Other North Sea flatfish species are also affected, but at a markedly lower prevalence. The condition is characterised by the occurrence of varying degrees of green to black patchy pigment spots in the skin of the upper (ocular) body side and pearly-white pigment spots in the skin of the lower (abocular) body side. In the course of fish disease monitoring programmes carried out by Germany and the UK (England and Scotland), a pronounced spatial pattern of hyperpigmentation has been detected in the North Sea. An increase in prevalence has been recorded in almost all North Sea areas studied in the past 2 decades. The prevalence recorded in hot spot areas of the condition increased from 5 to >40% between 1988 and 2009. Analysis of the German data indicates that the prevalence and intensity (degree of discolouration) of hyperpigmentation increase with size and age, indicating a temporal progression of the condition with size and age. Intense hyperpigmentation is associated with increased growth (length) and decreased condition factor. Potential causes of the condition (UV-B radiation nutrition, water temperature increase, demographic changes) and, in particular, of the spatial/temporal patterns recorded as well as the relationship to host-specific factors (sex, age, length, growth, condition factor) are discussed.

  12. Spatial and temporal patterns of bioindicator mercury in pennsylvania oak forest.

    PubMed

    McClenahen, James R; Hutnik, Russell J; Davis, Donald D

    2013-01-01

    We monitored spatial and temporal patterns of total Hg in forest bioindicators to assess possible local, regional, and global changes in atmospheric Hg deposition. Total Hg concentrations were monitored in leaves and fresh litterfall of northern red oak ( L.), on an epiphytic moss ( Hedw.) on northern red oak stems, and in surface soil organic matter (O and O horizons) in Pennsylvania oak-dominated forests. Variously configured plots were used to monitor Hg deposition near local coal-fired generating stations and an industrial city and along an extended regional transect. Linearly decreasing temporal trends in Hg concentrations occurred in leaves, litterfall, moss, and soil O and O. Mean annual Hg concentrations were often greater near local emissions sources compared with remote areas, especially in the initial monitoring period. Decreasing time trends for different impact areas tended to converge due to greater rates of Hg decrease where initial bioindicator Hg levels were higher. Fresh litter and soil O showed the greatest overall potential as Hg bioindicators. We conclude that Hg deposition has been significantly decreasing over time throughout the study area as a result of locally and regionally declining Hg emissions. Reductions in Hg emissions are likely a co-benefit of the 1990 Clean Air Act regulations and changing industrial activities. Recent leveling of several bioindicator Hg time trends may foretell a shift in Hg depositional patterns. Mercury monitoring studies such as this fulfill a need for documenting local and regional effects of emissions reduction.

  13. Spatial and temporal patterns of enzootic raccoon rabies adjusted for multiple covariates

    PubMed Central

    Recuenco, Sergio; Eidson, Millicent; Kulldorff, Martin; Johnson, Glen; Cherry, Bryan

    2007-01-01

    Background With the objective of identifying spatial and temporal patterns of enzootic raccoon variant rabies, a spatial scan statistic was utilized to search for significant terrestrial rabies clusters by year in New York State in 1997–2003. Cluster analyses were unadjusted for other factors, adjusted for covariates, and adjusted for covariates and large scale geographic variation (LSGV). Adjustments were intended to identify the unusual aggregations of cases given the expected distribution based on the observed locations. Results Statistically significant clusters were identified particularly in the Albany, Finger Lakes, and South Hudson areas. The clusters were generally persistent in the Albany area, but demonstrated cyclical changes in rabies activity every few years in the other areas. Cluster adjustments allowed the discussion of possible causes for the high risk raccoon rabies areas identified. Conclusion This study analyzed raccoon variant rabies spatial and temporal patterns in New York that have not been previously described at a focal (census tract) level. Comparisons across the type of spatial analysis performed with various degrees of adjustment allow consideration of the potential influence of geographical factors for raccoon rabies and possible reasons for the highest risk areas (statistically significant clusters). PMID:17428324

  14. Temporal patterns of human and canine Giardia infection in the United States: 2003-2009.

    PubMed

    Mohamed, Ahmed S; Levine, Michael; Camp, Joseph W; Lund, Elisabeth; Yoder, Jonathan S; Glickman, Larry T; Moore, George E

    2014-02-01

    Giardia protozoa have been suspected to be of zoonotic transmission, including transmission from companion animals such as pet dogs to humans. Patterns of infection have been previously described for dogs and humans, but such investigations have used different time periods and locations for these two species. Our objective was to describe and compare the overall trend and seasonality of Giardia species infection among dogs and humans in the United States from 2003 through 2009 in an ecological study using public health surveillance data and medical records of pet dogs visiting a large nationwide private veterinary hospital. Canine data were obtained from all dogs visiting Banfield hospitals in the United States with fecal test results for Giardia species, from January 2003 through December 2009. Incidence data of human cases from the same time period were obtained from the CDC. Descriptive time plots, a seasonal trend decomposition (STL) procedure, and seasonal autoregressive moving-average (SARIMA) models were used to assess the temporal characteristics of Giardia infection in the two species. Canine incidence showed a gradual decline from 2003 to 2009 with no significant/distinct regular seasonal component. By contrast, human incidence showed a stable annual rate with a significant regular seasonal cycle, peaking in August and September. Different temporal patterns in human and canine Giardia cases observed in this study suggest that the epidemiological disease processes underlying both series might be different, and Giardia transmission between humans and their companion dogs seems uncommon.

  15. Quantifying positional and temporal movement patterns in professional rugby union using global positioning system.

    PubMed

    Jones, Marc R; West, Daniel J; Crewther, Blair T; Cook, Christian J; Kilduff, Liam P

    2015-01-01

    This study assessed the positional and temporal movement patterns of professional rugby union players during competition using global positioning system (GPS) units. GPS data were collected from 33 professional rugby players from 13 matches throughout the 2012-2013 season sampling at 10 Hz. Players wore GPS units from which information on distances, velocities, accelerations, exertion index, player load, contacts, sprinting and repeated high-intensity efforts (RHIE) were derived. Data files from players who played over 60 min (n = 112) were separated into five positional groups (tight and loose forwards; half, inside and outside backs) for match analysis. A further comparison of temporal changes in movement patterns was also performed using data files from those who played full games (n = 71). Significant positional differences were found for movement characteristics during performance (P < 0.05). Results demonstrate that inside and outside backs have greatest high-speed running demands; however, RHIE and contact demands are greatest in loose forwards during match play. Temporal analysis of all players displayed significant differences in player load, cruising and striding between halves, with measures of low- and high-intensity movement and acceleration/deceleration significantly declining throughout each half. Our data demonstrate significant positional differences for a number of key movement variables which provide a greater understanding of positional requirements of performance. This in turn may be used to develop progressive position-specific drills that elicit specific adaptations and provide objective measures of preparedness. Knowledge of performance changes may be used when developing drills and should be considered when monitoring and evaluating performance.

  16. Temporal and spatial pattern of dref expression during Drosophila bristle development.

    PubMed

    Kawamori, Akihito; Shimaji, Kouhei; Yamaguchi, Masamitsu

    2013-01-01

    The DNA replication-related element-binding factor (DREF) is a BED finger-type transcription factor that has important roles in cell cycle progression. In an earlier study, we showed that DREF is required for endoreplication during posterior scutellar macrochaete development. However, dynamic change in the dref expression in the cell lineage is unclear. In this study, we focused on the spatio-temporal pattern of expression of the dref gene during bristle development. Gene expression analysis using GAL4 enhancer trap lines of dref and the upstream activation sequence-green fluorescent protein with nuclear localization signals (UAS-GFPnls) in combination with immunostaining revealed the half-life of GFPnls in vivo (<6 hours) is short enough to monitor the dref gene expression. The analysis revealed that the dref expression occurs in clusters that include cells consisting of a bristle as well as surrounding epidermal cells. The intensity of GFP signals was almost the same in those cells, suggesting expression of the dref gene in bristle cell lineages occurs simultaneously in clusters. Further analysis showed that GFP signals increased twice during sensory organ precursor development as well as in bristle development at 9 hours and 15 hours after pupal formation, respectively. However, its expression was barely detectable in the cell lineages in and around asymmetric cell division or at other stages of development. For the first time, we clarified a spatio-temporal pattern of expression of the dref gene in vivo and revealed that expression of the dref gene occurs in clusters and is temporally regulated at specific times during bristle development.

  17. Temporal stability in patterns of genetic diversity and structure of a marine foundation species (Zostera marina).

    PubMed

    Reynolds, L K; Stachowicz, J J; Hughes, A R; Kamel, S J; Ort, B S; Grosberg, R K

    2017-04-01

    Genetic diversity and population structure reflect complex interactions among a diverse set of processes that may vary temporally, limiting their potential to predict ecological and evolutionary outcomes. Yet, the stability of these patterns is rarely tested. We resampled eelgrass (Zostera marina) meadows from published studies to determine variability in genetic diversity and structure within and between meadows over 5-12 years. The meadows sampled (San Francisco, Tomales and Bodega Bays in California and the Virginia coastal bays) represent a range of life histories (annual vs perennial), age (well-established vs restored) and environments (rural vs urbanized). In all of these systems, neither diversity nor differentiation (FST) changed over time. Differences among tidal heights within Bodega Bay were also remarkably consistent, with the high intertidal being more diverse than the subtidal, and tidal height differentiation being modest but significant at both time points. Historical studies used only a few microsatellite loci; therefore, our temporal comparisons were based on 4-5 loci. However, analysis of the current data using a set of 12 loci show that 4-5 loci are sufficient to describe diversity and differentiation patterns in this system. This temporal consistency was not because of the resampling of large clones, underscoring the feasibility and relevance of understanding drivers of the differences. Because seagrasses are declining at rapid rates, restoration and conservation are increasingly a coastal management priority. Our results argue that surveys of eelgrass genetic structure and diversity at decadal scales can provide accurate depictions of populations, increasing the utility of published genetic data for restoration and designing networks of reserves.

  18. 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

  19. Circadian variation in stroke onset: identical temporal pattern in ischemic and hemorrhagic events.

    PubMed

    Manfredini, Roberto; Boari, Benedetta; Smolensky, Michael H; Salmi, Raffaella; la Cecilia, Olga; Maria Malagoni, Anna; Haus, Erhard; Manfredini, Fabio

    2005-01-01

    Stroke is the culmination of a heterogeneous group of cerebrovascular diseases that is manifested as ischemia or hemorrhage of one or more blood vessels of the brain. The occurrence of many acute cardiovascular events--such as myocardial infarction, sudden cardiac death, pulmonary embolism, critical limb ischemia, and aortic aneurysm rupture--exhibits prominent 24 h patterning, with a major morning peak and secondary early evening peak. The incidence of stroke exhibits the same 24 h pattern. Although ischemic and hemorrhagic strokes are different entities and are characterized by different pathophysiological mechanisms, they share an identical double-peak 24 h pattern. A constellation of endogenous circadian rhythms and exogenous cyclic factors are involved. The staging of the circadian rhythms in vascular tone, coagulative balance, and blood pressure plus temporal patterns in posture, physical activity, emotional stress, and medication effects play central and/or triggering roles. Features of the circadian rhythm of blood pressure, in terms of their chronic and acute effects on cerebral vessels, and of coagulation are especially important. Clinical medicine has been most concerned with the prevention of stroke in the morning, when population-based studies show it is of greatest risk during the 24 h; however, improved protection of at-risk patients against stroke in the early evening, the second most vulnerable time of cerebrovascular accidents, has received relatively little attention thus far.

  20. 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.

  1. Gender Differences in Speech Temporal Patterns Detected Using Lagged Co-Occurrence Text-Analysis of Personal Narratives

    ERIC Educational Resources Information Center

    Cohen, Shuki J.

    2009-01-01

    This paper describes a novel methodology for the detection of speech patterns. Lagged co-occurrence analysis (LCA) utilizes the likelihood that a target word will be uttered in a certain position after a trigger word. Using this methodology, it is possible to uncover a statistically significant repetitive temporal patterns of word use, compared to…

  2. Seasonal and temporal patterns of NDMA formation potentials in surface waters.

    PubMed

    Uzun, Habibullah; Kim, Daekyun; Karanfil, Tanju

    2015-02-01

    The seasonal and temporal patterns of N-nitrosodimethylamine (NDMA) formation potentials (FPs) were examined with water samples collected monthly for 21 month period in 12 surface waters. This long term study allowed monitoring the patterns of NDMA FPs under dynamic weather conditions (e.g., rainy and dry periods) covering several seasons. Anthropogenically impacted waters which were determined by high sucralose levels (>100 ng/L) had higher NDMA FPs than limited impacted sources (<100 ng/L). In most sources, NDMA FP showed more variability in spring months, while seasonal mean values remained relatively consistent. The study also showed that watershed characteristics played an important role in the seasonal and temporal patterns. In the two dam-controlled river systems (SW A and G), the NDMA FP levels at the downstream sampling locations were controlled by the NDMA levels in the dams independent of either the increases in discharge rates due to water releases from the dams prior to or during the heavy rain events or intermittent high NDMA FP levels observed at the upstream of dams. The large reservoirs and impoundments on rivers examined in this study appeared serving as an equalization basin for NDMA precursors. On the other hand, in a river without an upstream reservoir (SW E), the NDMA levels were influenced by the ratio of an upstream wastewater treatment plant (WWTP) effluent discharge to the river discharge rate. The impact of WWTP effluent decreased during the high river flow periods due to rain events. Linear regression with independent variables DOC, DON, and sucralose yielded poor correlations with NDMA FP (R(2) < 0.27). Multiple linear regression analysis using DOC and log [sucralose] yielded a better correlation with NDMA FP (R(2) = 0.53).

  3. Detecting spatio-temporal controls on depth distributions of root water uptake using soil moisture patterns

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Heidbüchel, Ingo; Simard, Sonia; Güntner, Andreas; Weiler, Markus

    2016-04-01

    Landscape scale soil moisture patterns show a pronounced shift when plants become active during the growing season. Soil moisture patterns are then not only controlled by soils, topography and related abiotic site characteristics as well as site characteristic throughfall patterns but also by root water uptake. In this study root water uptake from different soil depths is estimated based on diurnal fluctuations in soil moisture content and was investigated with a setup of 15 field sites in a forest in northeastern Germany. These sites cover different topographic positions and forest stands. Vegetation types include pine forest (young and old) and different deciduous forest stands. Available data at all sites includes information at high temporal resolution from 5 soil moisture and soil temperature profiles, matric potential, piezometers and sapflow sensors as well as standard climate data. The resulting comprehensive data set of depth distributed root water uptake shows differences in overall amounts as well as in uptake depth distributions between different forest stands, but also related to slope position and thus depth to groundwater. Temporal dynamics of signal strength within the profile suggest a locally shifting spatial distribution of root water uptake depending on water availability. The relative contributions of the different depths to overall root water uptake shift as the summer progresses. However, the relationship of these depth resolved uptake rates to overall soil water availability varies considerably between tree species. This unique data set of depth specific contributions to root water uptake down to a depth of 2 m allows a much more detailed analysis of tree response to water availability than the more common transpiration estimates generated by sapflow or eddy flux measurements.

  4. The use of census migration data to approximate human movement patterns across temporal scales.

    PubMed

    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.

  5. 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.

  6. Spatio-temporal patterns of soil erosion and suspended sediment dynamics in the Mekong River Basin.

    PubMed

    Suif, Zuliziana; Fleifle, Amr; Yoshimura, Chihiro; Saavedra, Oliver

    2016-10-15

    Understanding of the distribution patterns of sediment erosion, concentration and transport in river basins is critically important as sediment plays a major role in river basin hydrophysical and ecological processes. In this study, we proposed an integrated framework for the assessment of sediment dynamics, including soil erosion (SE), suspended sediment load (SSL) and suspended sediment concentration (SSC), and applied this framework to the Mekong River Basin. The Revised Universal Soil Loss Equation (RUSLE) model was adopted with a geographic information system to assess SE and was coupled with a sediment accumulation and a routing scheme to simulate SSL. This framework also analyzed Landsat imagery captured between 1987 and 2000 together with ground observations to interpolate spatio-temporal patterns of SSC. The simulated SSL results from 1987 to 2000 showed the relative root mean square error of 41% and coefficient of determination (R(2)) of 0.89. The polynomial relationship of the near infrared exoatmospheric reflectance and the band 4 wavelength (760-900nm) to the observed SSC at 9 sites demonstrated the good agreement (overall relative RMSE=5.2%, R(2)=0.87). The result found that the severe SE occurs in the upper (China and Lao PDR) and lower (western part of Vietnam) regions. The SSC in the rainy season (June-November) showed increasing and decreasing trends longitudinally in the upper (China and Lao PDR) and lower regions (Cambodia), respectively, while the longitudinal profile of SSL showed a fluctuating trend along the river in the early rainy season. Overall, the results described the unique spatio-temporal patterns of SE, SSL and SSC in the Mekong River Basin. Thus, the proposed integrated framework is useful for elucidating complex process of sediment generation and transport in the land and river systems of large river basins.

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

    PubMed

    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.

  8. 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

  9. Benefiting from a migratory prey: spatio-temporal patterns in allochthonous subsidization of an Arctic predator.

    PubMed

    Giroux, Marie-Andrée; Berteaux, Dominique; Lecomte, Nicolas; Gauthier, Gilles; Szor, Guillaume; Bêty, Joël

    2012-05-01

    1. Flows of nutrients and energy across ecosystem boundaries have the potential to subsidize consumer populations and modify the dynamics of food webs, but how spatio-temporal variations in autochthonous and allochthonous resources affect consumers' subsidization remains largely unexplored. 2. We studied spatio-temporal patterns in the allochthonous subsidization of a predator living in a relatively simple ecosystem. We worked on Bylot Island (Nunavut, Canada), where arctic foxes (Vulpes lagopus L.) feed preferentially on lemmings (Lemmus trimucronatus and Dicrostonyx groenlandicus Traill), and alternatively on colonial greater snow geese (Anser caerulescens atlanticus L.). Geese migrate annually from their wintering grounds (where they feed on farmlands and marshes) to the Canadian Arctic, thus generating a strong flow of nutrients and energy across ecosystem boundaries. 3. We examined the influence of spatial variations in availability of geese on the diet of fox cubs (2003-2005) and on fox reproductive output (1996-2005) during different phases of the lemming cycle. 4. Using stable isotope analysis and a simple statistical routine developed to analyse the outputs of a multisource mixing model (SIAR), we showed that the contribution of geese to the diet of arctic fox cubs decreased with distance from the goose colony. 5. The probability that a den was used for reproduction by foxes decreased with distance from the subsidized goose colony and increased with lemming abundance. When lemmings were highly abundant, the effect of distance from the colony disappeared. The goose colony thus generated a spatial patterning of reproduction probability of foxes, while the lemming cycle generated a strong temporal variation of reproduction probability of foxes. 6. This study shows how the input of energy owing to the large-scale migration of prey affects the functional and reproductive responses of an opportunistic consumer, and how this input is spatially and

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

    SciTech Connect

    Altman, Michael B.; Chmura, Steven J.; Deasy, Joseph O.; Roeske, John C. . 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.

  11. Spatio-temporal dynamics of global H5N1 outbreaks match bird migration patterns.

    PubMed

    Si, Yali; Skidmore, Andrew K; Wang, Tiejun; de Boer, Willem F; Debba, Pravesh; Toxopeus, Albert G; Li, Lin; Prins, Herbert H T

    2009-11-01

    The global spread of highly pathogenic avian influenza H5N1 in poultry, wild birds and humans, poses a significant pandemic threat and a serious public health risk. An efficient surveillance and disease control system relies on the understanding of the dispersion patterns and spreading mechanisms of the virus. A space-time cluster analysis of H5N1 outbreaks was used to identify spatio-temporal patterns at a global scale and over an extended period of time. Potential mechanisms explaining the spread of the H5N1 virus, and the role of wild birds, were analyzed. Between December 2003 and December 2006, three global epidemic phases of H5N1 influenza were identified. These H5N1 outbreaks showed a clear seasonal pattern, with a high density of outbreaks in winter and early spring (i.e., October to March). In phase I and II only the East Asia Australian flyway was affected. During phase III, the H5N1 viruses started to appear in four other flyways: the Central Asian flyway, the Black Sea Mediterranean flyway, the East Atlantic flyway and the East Africa West Asian flyway. Six disease cluster patterns along these flyways were found to be associated with the seasonal migration of wild birds. The spread of the H5N1 virus, as demonstrated by the space-time clusters, was associated with the patterns of migration of wild birds. Wild birds may therefore play an important role in the spread of H5N1 over long distances. Disease clusters were also detected at sites where wild birds are known to overwinter and at times when migratory birds were present. This leads to the suggestion that wild birds may also be involved in spreading the H5N1 virus over short distances.

  12. Relationship between Musical Characteristics and Temporal Breathing Pattern in Piano Performance.

    PubMed

    Sakaguchi, Yutaka; Aiba, Eriko

    2016-01-01

    Although there is growing evidence that breathing is modulated by various motor and cognitive activities, the nature of breathing in musical performance has been little explored. The present study examined the temporal breath pattern in piano performance, aiming to elucidate how breath timing is related to musical organization/events and performance. In the experiments, the respiration of 15 professional and amateur pianists, playing 10 music excerpts in total (from four-octave C major scale, Hanon's exercise, J. S. Bach's Invention, Mozart's Sonatas, and Debussy's Clair de lune), was monitored by capnography. The relationship between breathing and musical characteristics was analyzed. Five major results were obtained. (1) Mean breath interval was shortened for excerpts in faster tempi. (2) Fluctuation of breath intervals was reduced for the pieces for finger exercise and those in faster tempi. Pianists showing large within-trial fluctuation also exhibited large inter-excerpt difference. (3) Inter-trial consistency of the breath patterns depended on the excerpts. Consistency was generally reduced for the excerpts that could be performed mechanically (i.e., pieces for finger exercise), but interestingly, one third of the participant showed consistent patterns for the simple scale, correlated with the ascending/descending sequences. (4) Pianists tended to exhale just after the music onsets, inhale at the rests, and inhibit inhale during the slur parts. There was correlation between breathing pattern and two-voice polyphonic structure for several participants. (5) Respiratory patterns were notably different among the pianists. Every pianist showed his or her own characteristic features commonly for various musical works. These findings suggest that breathing in piano performance depends not only on musical parameters and organization written in the score but also some pianist-dependent factors which might be ingrained to individual pianists.

  13. Relationship between Musical Characteristics and Temporal Breathing Pattern in Piano Performance

    PubMed Central

    Sakaguchi, Yutaka; Aiba, Eriko

    2016-01-01

    Although there is growing evidence that breathing is modulated by various motor and cognitive activities, the nature of breathing in musical performance has been little explored. The present study examined the temporal breath pattern in piano performance, aiming to elucidate how breath timing is related to musical organization/events and performance. In the experiments, the respiration of 15 professional and amateur pianists, playing 10 music excerpts in total (from four-octave C major scale, Hanon's exercise, J. S. Bach's Invention, Mozart's Sonatas, and Debussy's Clair de lune), was monitored by capnography. The relationship between breathing and musical characteristics was analyzed. Five major results were obtained. (1) Mean breath interval was shortened for excerpts in faster tempi. (2) Fluctuation of breath intervals was reduced for the pieces for finger exercise and those in faster tempi. Pianists showing large within-trial fluctuation also exhibited large inter-excerpt difference. (3) Inter-trial consistency of the breath patterns depended on the excerpts. Consistency was generally reduced for the excerpts that could be performed mechanically (i.e., pieces for finger exercise), but interestingly, one third of the participant showed consistent patterns for the simple scale, correlated with the ascending/descending sequences. (4) Pianists tended to exhale just after the music onsets, inhale at the rests, and inhibit inhale during the slur parts. There was correlation between breathing pattern and two-voice polyphonic structure for several participants. (5) Respiratory patterns were notably different among the pianists. Every pianist showed his or her own characteristic features commonly for various musical works. These findings suggest that breathing in piano performance depends not only on musical parameters and organization written in the score but also some pianist-dependent factors which might be ingrained to individual pianists. PMID:27516736

  14. Temporal patterns and geographic heterogeneity of Zika virus (ZIKV) outbreaks in French Polynesia and Central America

    PubMed Central

    2017-01-01

    Background Zika virus (ZIKV) transmission has been reported in 67 countries/territories in the Oceania region and the Americas since 2015, prompting the World Health Organization (WHO) to declare ZIKV as a Public Health Emergency of International Concern in February 2016, due to its strong association with medical complications such as microcephaly and Guillain–Barré Syndrome (GBS). However, a substantial gap in knowledge still exists regarding differing temporal pattern and potential of transmission of ZIKV in different regions of the world. Methods We use a phenomenological model to ascertain the temporal patterns and transmission potential of ZIKV in various countries/territories, by fitting the model to Zika case data from Yap Island and French Polynesia in the Oceania region and 11 countries/territories with confirmed case data, namely, Colombia, Ecuador, French Guiana, Guadeloupe, Guatemala, Mexico, Nicaragua, Panama, Puerto Rico, Saint Martin, and Suriname, to pinpoint the waves of infections in each country/territory and to estimate the respective basic reproduction number R0. Results Six of these time series datasets resulted in statistically significant model fit of at least one wave of reported cases, namely that of French Polynesia, Colombia, Puerto Rico, Guatemala, Suriname and Saint Martin. However, only Colombia and Guatemala exhibited two waves of cases while the others had only one wave. Temporal patterns of the second wave in Colombia and the single wave in Suriname are very similar, with the respective turning points separated by merely a week. Moreover, the mean estimates of R0 for Colombia, Guatemala and Suriname, all land-based populations, range between 1.05 and 1.75, while the corresponding mean estimates for R0 of island populations in French Polynesia, Puerto Rico and Saint Martin are significantly lower with a range of 5.70–6.89. We also fit the Richards model to Zika case data from six main archipelagos in French Polynesia

  15. Temporal Pattern Recognition: A Network Architecture For Multi-Sensor Fusion

    NASA Astrophysics Data System (ADS)

    Priebe, C. E.; Marchette, D. J.

    1989-03-01

    A self-organizing network architecture for the learning and recognition of temporal patterns is proposed. This multi-layered architecture has as its focal point a layer of multi-dimensional Gaussian classification nodes, and the learning scheme employed is based on standard statistical moving mean and moving covariance calculations. The nodes are implemented in the network architecture by using a Gaussian, rather than sigmoidal, transfer function acting on the input from numerous connections. Each connection is analogous to a separate dimension for the Gaussian function. The learning scheme is a one-pass method, eliminating the need for repetitive presentation of the teaching stimuli. The Gaussian classes developed are representative of the statistics of the teaching data and act as templates in classifying novel inputs. The input layer employs a time-based decay to develop a time-ordered representation of the input stimuli. This temporal pattern recognition architecture is used to perform multi-sensor fusion and scene analysis for ROBART II, an autonomous sentry robot employing heterogeneous and homogeneous binary (on / off) sensors. The system receives sensor packets from ROBART indicating which sensors are active. The packets from various sensors are integrated in the input layer. As time progresses these sensor outputs become ordered, allowing the system to recognize activities which are dependent, not only on the individual events which make up the activity, but also on the order in which these events occur and their relative spacing throughout time. Each Gaussian classification node, representing a learned activity as an ordered sequence of sensor outputs, calculates its activation value independently, based on the activity in the input layer. These Gaussian activation values are then used to determine which, if any, of the learned sequences are present and with what confidence. The classification system is capable of recognizing activities despite missing

  16. Patterns of spatial and temporal variability of UV transparency in Lake Tahoe, California-Nevada

    NASA Astrophysics Data System (ADS)

    Rose, Kevin C.; Williamson, Craig E.; Schladow, S. Geoff; Winder, Monika; Oris, James T.

    2009-06-01

    Lake Tahoe is an ultra-oligotrophic subalpine lake that is renowned for its clarity. The region experiences little cloud cover and is one of the most UV transparent lakes in the world. As such, it is an ideal environment to study the role of UV radiation in aquatic ecosystems. Long-term trends in Secchi depths showed that water transparency to visible light has decreased in recent decades, but limited data are available on the UV transparency of the lake. Here we examine how ultraviolet radiation varies relative to longer-wavelength photosynthetically active radiation (PAR, 400-700 nm, visible wavelengths) horizontally along inshore-offshore transects in the lake and vertically within the water column as well as temporally throughout 2007. UV transparency was more variable than PAR transparency horizontally across the lake and throughout the year. Seasonal patterns of Secchi transparency differed from both UV and PAR, indicating that different substances may be responsible for controlling transparency to UV, PAR, and Secchi. In surface waters, UVA (380 nm) often attenuated more slowly than PAR, a pattern visible in only exceptionally transparent waters with very low dissolved organic carbon. On many sampling dates, UV transparency decreased progressively with depth suggesting surface photobleaching, reductions in particulate matter, increasing chlorophyll a, or some combination of these increased during summer months. Combining these patterns of UV transparency with data on visible light provides a more comprehensive understanding of ecosystem structure, function, and effects of environmental change in highly transparent alpine and subalpine lakes such as Tahoe.

  17. 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

  18. Temporal Patterns of Snow Accumulation and the Effect of Nearby Summit, Greenland

    NASA Astrophysics Data System (ADS)

    Kelson, J.; Hawley, R. L.; Lutz, E.

    2012-12-01

    The mass balance of a glacier reflects how the mass of the ice sheet changes over time, which reflects climate change and could affect sea level rise. The rate at which snow accumulates is essential for calculating the mass balance of the Greenland ice sheet. We examine the accumulation measured monthly from 2006 to 2011 at 121 stakes in a stepping line near Summit, Greenland. We investigate the temporal patterns in accumulation with a monthly resolution. We find that seasonally, September experiences the most accumulation. We also determine that there is no significant change in accumulation rates over the study period. We then examine the spatial patterns of accumulation in order to determine if the accumulation record from the stakes can be considered an accurate estimate for regional accumulation patterns. We find that the accumulation surface is very smooth at our sampling scale; there are no ridge or trough features that might cause unrepresentative data. However, the stake line experiences increased accumulation in the South, which may be a snowdrift caused by the structures of nearby Summit Camp. Considering the possibility of drift from Summit, the accumulation measurements near the southern end of the stake line cannot be used as a regional estimate for accumulation.

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

    PubMed

    Bourobou, Serge Thomas Mickala; Yoo, Younghwan

    2015-05-21

    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.

  20. Rationalizing spatial exploration patterns of wild animals and humans through a temporal discounting framework.

    PubMed

    Namboodiri, Vijay Mohan K; Levy, Joshua M; Mihalas, Stefan; Sims, David W; Hussain Shuler, Marshall G

    2016-08-02

    Understanding the exploration patterns of foragers in the wild provides fundamental insight into animal behavior. Recent experimental evidence has demonstrated that path lengths (distances between consecutive turns) taken by foragers are well fitted by a power law distribution. Numerous theoretical contributions have posited that "Lévy random walks"-which can produce power law path length distributions-are optimal for memoryless agents searching a sparse reward landscape. It is unclear, however, whether such a strategy is efficient for cognitively complex agents, from wild animals to humans. Here, we developed a model to explain the emergence of apparent power law path length distributions in animals that can learn about their environments. In our model, the agent's goal during search is to build an internal model of the distribution of rewards in space that takes into account the cost of time to reach distant locations (i.e., temporally discounting rewards). For an agent with such a goal, we find that an optimal model of exploration in fact produces hyperbolic path lengths, which are well approximated by power laws. We then provide support for our model by showing that humans in a laboratory spatial exploration task search space systematically and modify their search patterns under a cost of time. In addition, we find that path length distributions in a large dataset obtained from free-ranging marine vertebrates are well described by our hyperbolic model. Thus, we provide a general theoretical framework for understanding spatial exploration patterns of cognitively complex foragers.

  1. A review on the temporal pattern of deer-vehicle accidents: impact of seasonal, diurnal and lunar effects in cervids.

    PubMed

    Steiner, Wolfgang; Leisch, Friedrich; Hackländer, Klaus

    2014-05-01

    The increasing number of deer-vehicle-accidents (DVAs) and the resulting economic costs have promoted numerous studies on behavioural and environmental factors which may contribute to the quantity, spatiotemporal distribution and characteristics of DVAs. Contrary to the spatial pattern of DVAs, data of their temporal pattern is scarce and difficult to obtain because of insufficient accuracy in available datasets, missing standardization in data aquisition, legal terms and low reporting rates to authorities. Literature of deer-traffic collisions on roads and railways is reviewed to examine current understanding of DVA temporal trends. Seasonal, diurnal and lunar peak accident periods are identified for deer, although seasonal pattern are not consistent among and within species or regions and data on effects of lunar cycles on DVAs is almost non-existent. Cluster analysis of seasonal DVA data shows nine distinct clusters of different seasonal DVA pattern for cervid species within the reviewed literature. Studies analyzing the relationship between time-related traffic predictors and DVAs yield mixed results. Despite the seasonal dissimilarity, diurnal DVA pattern are comparatively constant in deer, resulting in pronounced DVA peaks during the hours of dusk and dawn frequently described as bimodal crepuscular pattern. Behavioural aspects in activity seem to have the highest impact in DVAs temporal trends. Differences and variations are related to habitat-, climatic- and traffic characteristics as well as effects of predation, hunting and disturbance. Knowledge of detailed temporal DVA pattern is essential for prevention management as well as for the application and evaluation of mitigation measures.

  2. Effects of subsampling of passive acoustic recordings on acoustic metrics.

    PubMed

    Thomisch, Karolin; Boebel, Olaf; Zitterbart, Daniel P; Samaran, Flore; Van Parijs, Sofie; Van Opzeeland, Ilse

    2015-07-01

    Passive acoustic monitoring is an important tool in marine mammal studies. However, logistics and finances frequently constrain the number and servicing schedules of acoustic recorders, requiring a trade-off between deployment periods and sampling continuity, i.e., the implementation of a subsampling scheme. Optimizing such schemes to each project's specific research questions is desirable. This study investigates the impact of subsampling on the accuracy of two common metrics, acoustic presence and call rate, for different vocalization patterns (regimes) of baleen whales: (1) variable vocal activity, (2) vocalizations organized in song bouts, and (3) vocal activity with diel patterns. To this end, above metrics are compared for continuous and subsampled data subject to different sampling strategies, covering duty cycles between 50% and 2%. The results show that a reduction of the duty cycle impacts negatively on the accuracy of both acoustic presence and call rate estimates. For a given duty cycle, frequent short listening periods improve accuracy of daily acoustic presence estimates over few long listening periods. Overall, subsampling effects are most pronounced for low and/or temporally clustered vocal activity. These findings illustrate the importance of informed decisions when applying subsampling strategies to passive acoustic recordings or analyses for a given target species.

  3. Wildlife in the Matrix: Spatio-Temporal Patterns of Herbivore Occurrence in Karnataka, India

    NASA Astrophysics Data System (ADS)

    Karanth, Krithi K.

    2016-01-01

    Wildlife reserves are becoming increasingly isolated from the surrounding human-dominated landscapes particularly in Asia. It is imperative to understand how species are distributed spatially and temporally in and outside reserves, and what factors influence their occurrence. This study surveyed 7500 km2 landscape surrounding five reserves in the Western Ghats to examine patterns of occurrence of five herbivores: elephant, gaur, sambar, chital, and pig. Species distributions are modeled spatio-temporally using an occupancy approach. Trained field teams conducted 3860 interview-based occupancy surveys in a 10-km buffer surrounding these five reserves in 2012. I found gaur and wild pig to be the least and most wide-ranging species, respectively. Elephant and chital exhibit seasonal differences in spatial distribution unlike the other three species. As predicted, distance to reserve, the reserve itself, and forest cover were associated with higher occupancy of all species, and higher densities of people negatively influenced occurrence of all species. Park management, species protection, and conflict mitigation efforts in this landscape need to incorporate temporal and spatial understanding of species distributions. All species are known crop raiders and conflict prone locations with resources (such as water and forage) have to be monitored and managed carefully. Wildlife reserves and adjacent areas are critical for long-term persistence and habitat use for all five herbivores and must be monitored to ensure wildlife can move freely. Such a large-scale approach to map and monitor species distributions can be adapted to other landscapes to identify and monitor critical habitats shared by people and wildlife.

  4. Wildlife in the Matrix: Spatio-Temporal Patterns of Herbivore Occurrence in Karnataka, India.

    PubMed

    Karanth, Krithi K

    2016-01-01

    Wildlife reserves are becoming increasingly isolated from the surrounding human-dominated landscapes particularly in Asia. It is imperative to understand how species are distributed spatially and temporally in and outside reserves, and what factors influence their occurrence. This study surveyed 7500 km(2) landscape surrounding five reserves in the Western Ghats to examine patterns of occurrence of five herbivores: elephant, gaur, sambar, chital, and pig. Species distributions are modeled spatio-temporally using an occupancy approach. Trained field teams conducted 3860 interview-based occupancy surveys in a 10-km buffer surrounding these five reserves in 2012. I found gaur and wild pig to be the least and most wide-ranging species, respectively. Elephant and chital exhibit seasonal differences in spatial distribution unlike the other three species. As predicted, distance to reserve, the reserve itself, and forest cover were associated with higher occupancy of all species, and higher densities of people negatively influenced occurrence of all species. Park management, species protection, and conflict mitigation efforts in this landscape need to incorporate temporal and spatial understanding of species distributions. All species are known crop raiders and conflict prone locations with resources (such as water and forage) have to be monitored and managed carefully. Wildlife reserves and adjacent areas are critical for long-term persistence and habitat use for all five herbivores and must be monitored to ensure wildlife can move freely. Such a large-scale approach to map and monitor species distributions can be adapted to other landscapes to identify and monitor critical habitats shared by people and wildlife.

  5. Monitoring, analyzing and simulating of spatial-temporal changes of landscape pattern over mining area

    NASA Astrophysics Data System (ADS)

    Liu, Pei; Han, Ruimei; Wang, Shuangting

    2014-11-01

    According to the merits of remotely sensed data in depicting regional land cover and Land changes, multi- objective information processing is employed to remote sensing images to analyze and simulate land cover in mining areas. In this paper, multi-temporal remotely sensed data were selected to monitor the pattern, distri- bution and trend of LUCC and predict its impacts on ecological environment and human settlement in mining area. The monitor, analysis and simulation of LUCC in this coal mining areas are divided into five steps. The are information integration of optical and SAR data, LULC types extraction with SVM classifier, LULC trends simulation with CA Markov model, landscape temporal changes monitoring and analysis with confusion matrixes and landscape indices. The results demonstrate that the improved data fusion algorithm could make full use of information extracted from optical and SAR data; SVM classifier has an efficient and stable ability to obtain land cover maps, which could provide a good basis for both land cover change analysis and trend simulation; CA Markov model is able to predict LULC trends with good performance, and it is an effective way to integrate remotely sensed data with spatial-temporal model for analysis of land use / cover change and corresponding environmental impacts in mining area. Confusion matrixes are combined with landscape indices to evaluation and analysis show that, there was a sustained downward trend in agricultural land and bare land, but a continues growth trend tendency in water body, forest and other lands, and building area showing a wave like change, first increased and then decreased; mining landscape has undergone a from small to large and large to small process of fragmentation, agricultural land is the strongest influenced landscape type in this area, and human activities are the primary cause, so the problem should be pay more attentions by government and other organizations.

  6. Temporal patterns of emergency calls of a metropolitan city in China

    NASA Astrophysics Data System (ADS)

    Wang, Wenjun; Yuan, Ning; Pan, Lin; Jiao, Pengfei; Dai, Weidi; Xue, Guixiang; Liu, Dong

    2015-10-01

    Quantitative understanding of human communication behavior, one of the fundamental human activities, is of great value in many practical problems, ranging from urban planning to emergency management. Most of the recent studies have focused on human communication under normal situations. Here, we study the temporal patterns of emergency calls, which is a special kind of human communication activity under emergency circumstances, by analyzing a dataset of emergency call records that collected from a metropolitan city in China during a five year period. We find that most individuals rarely make emergency calls. The distribution of inter-call durations decays as double power law along with an exponential tail. We also discover that, comparing with the normal communication activities, the activity of calling the emergency number shows more significant characteristics of burstiness and memory. We further demonstrate that the behavior of calling the emergency number when people encounter extreme events could be explained by an event-driven memory process.

  7. Differentiation of bacterial colonies and temporal growth patterns using hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Mehrübeoglu, Mehrube; Buck, Gregory W.; Livingston, Daniel W.

    2014-09-01

    Detection and identification of bacteria are important for health and safety. Hyperspectral imaging offers the potential to capture unique spectral patterns and spatial information from bacteria which can then be used to detect and differentiate bacterial species. Here, hyperspectral imaging has been used to characterize different bacterial colonies and investigate their growth over time. Six bacterial species (Pseudomonas fluorescens, Escherichia coli, Serratia marcescens, Salmonella enterica, Staphylococcus aureus, Enterobacter aerogenes) were grown on tryptic soy agar plates. Hyperspectral data were acquired immediately after, 24 hours after, and 96 hours after incubation. Spectral signatures from bacterial colonies demonstrated repeatable measurements for five out of six species. Spatial variations as well as changes in spectral signatures were observed across temporal measurements within and among species at multiple wavelengths due to strengthening or weakening reflectance signals from growing bacterial colonies based on their pigmentation. Between-class differences and within-class similarities were the most prominent in hyperspectral data collected 96 hours after incubation.

  8. Mosses as biomonitors of atmospheric heavy metal deposition: spatial patterns and temporal trends in Europe.

    PubMed

    Harmens, H; Norris, D A; Steinnes, E; Kubin, E; Piispanen, J; Alber, R; Aleksiayenak, Y; Blum, O; Coşkun, M; Dam, M; De Temmerman, L; Fernández, J A; Frolova, M; Frontasyeva, M; González-Miqueo, L; Grodzińska, K; Jeran, Z; Korzekwa, S; Krmar, M; Kvietkus, K; Leblond, S; Liiv, S; Magnússon, S H; Mankovská, B; Pesch, R; Rühling, A; Santamaria, J M; Schröder, W; Spiric, Z; Suchara, I; Thöni, L; Urumov, V; Yurukova, L; Zechmeister, H G

    2010-10-01

    In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found.

  9. 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

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

    NASA Astrophysics Data System (ADS)

    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

    2013-08-01

    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.

  11. Phase extraction from two phase-shifting fringe patterns using spatial-temporal fringes method.

    PubMed

    Zhu, Ronggang; Li, Bo; Zhu, Rihong; He, Yong; Li, Jianxin

    2016-04-04

    Phase extraction from phase-shifting fringe patterns with unknown phase shift values is a valuable but challenging task, especially when there are only two frames of fringes. In this paper, a phase demodulation method based on the spatial-temporal fringes (STF) method is proposed, where two phase shift fringes with linear carrier are fused into one STF image, and then the measured phase can be extracted from its frequency spectrum. The algorithm is deduced by extending the traditional STF theory with at least three frames of fringes to the two frames case. In the simulations, its performance is compared with the classical Fourier Transform method, and the different carrier and phase step conditions are analyzed where the accuracy can be ensured in most cases. The algorithm is also validated by the experiment, where the reliable result can be given even if the phase shift changes within a wide range.

  12. Remote sensing captures varying temporal patterns of vegetation between human-altered and natural landscapes

    PubMed Central

    Roderick, George K.

    2015-01-01

    Global change has led to shifts in phenology, potentially disrupting species interactions such as plant–pollinator relationships. Advances in remote sensing techniques allow one to detect vegetation phenological diversity between different land use types, but it is not clear how this translates to other communities in the ecosystem. Here, we investigated the phenological diversity of the vegetation across a human-altered landscape including urban, agricultural, and natural land use types. We found that the patterns of change in the vegetation indices (EVI and NDVI) of human-altered landscapes are out of synchronization with the phenology in neighboring natural California grassland habitat. Comparing these findings to a spatio-temporal pollinator distribution dataset, EVI and NDVI were significant predictors of total bee abundance, a relationship that improved with time lags. This evidence supports the importance of differences in temporal dynamics between land use types. These findings also highlight the potential to utilize remote sensing data to make predictions for components of biodiversity that have tight vegetation associations, such as pollinators. PMID:26290795

  13. Temporal matching among diurnal photosynthetic patterns within the crown of the evergreen sclerophyll Olea europaea L.

    PubMed

    Granado-Yela, C; García-Verdugo, C; Carrillo, K; Rubio DE Casas, R; Kleczkowski, L A; Balaguer, L

    2011-05-01

    Trees are modular organisms that adjust their within-crown morphology and physiology in response to within-crown light gradients. However, whether within-plant variation represents a strategy for optimizing light absorption has not been formally tested. We investigated the arrangement of the photosynthetic surface throughout one day and its effects on the photosynthetic process, at the most exposed and most sheltered crown layers of a wild olive tree (Olea europaea L.). Similar measurements were made for cuttings taken from this individual and grown in a greenhouse at contrasted irradiance-levels (100 and 20% full sunlight). Diurnal variations in light interception, carbon fixation and carbohydrate accumulation in sun leaves were negatively correlated with those in shade leaves under field conditions when light intensity was not limiting. Despite genetic identity, these complementary patterns were not found in plants grown in the greenhouse. The temporal disparity among crown positions derived from specialization of the photosynthetic behaviour at different functional and spatial scales: architectural structure (crown level) and carbon budget (leaf level). Our results suggest that the profitability of producing a new module may not only respond to construction costs or light availability, but also rely on its spatio-temporal integration within the productive processes at the whole-crown level.

  14. Remote sensing captures varying temporal patterns of vegetation between human-altered and natural landscapes.

    PubMed

    Leong, Misha; Roderick, George K

    2015-01-01

    Global change has led to shifts in phenology, potentially disrupting species interactions such as plant-pollinator relationships. Advances in remote sensing techniques allow one to detect vegetation phenological diversity between different land use types, but it is not clear how this translates to other communities in the ecosystem. Here, we investigated the phenological diversity of the vegetation across a human-altered landscape including urban, agricultural, and natural land use types. We found that the patterns of change in the vegetation indices (EVI and NDVI) of human-altered landscapes are out of synchronization with the phenology in neighboring natural California grassland habitat. Comparing these findings to a spatio-temporal pollinator distribution dataset, EVI and NDVI were significant predictors of total bee abundance, a relationship that improved with time lags. This evidence supports the importance of differences in temporal dynamics between land use types. These findings also highlight the potential to utilize remote sensing data to make predictions for components of biodiversity that have tight vegetation associations, such as pollinators.

  15. Temporal and spatial patterns of aquatic macrophyte diversity in the Upper Paraná River floodplain.

    PubMed

    Thomaz, S M; Carvalho, P; Padial, A A; Kobayashi, J T

    2009-06-01

    Although the importance of long-term data has been emphasized by ecologists in recent years, little is known about how communities may change over time. In this study, we describe the general patterns of aquatic macrophyte diversity in the Paraná River floodplain observed during six years of study. Temporal changes in community composition were also evaluated. Data on the presence or absence of aquatic macrophytes were collected between March 2002 and March 2008, in six lakes associated with three rivers. Different analytical strategies were used to evaluate the dynamics of aquatic macrophyte communities between the different systems in the floodplain. The composition of aquatic macrophytes differed among the rivers, mainly with respect to the different vegetation life forms (floating, submersed, emergent and rooted with floating stems). The temporal similarity of species composition during the six years and the beta-diversity index indicated that the month-to-month species turnover was, in general, lower in the connected lakes, which are directly influenced by the river. Probably the water level fluctuation is a selective force that contributes to maintaining diversity or richness. Our findings indicated the importance of abiotic characteristics and connectivity of the lakes in determining macrophyte composition and community stability over a long time frame.

  16. 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

  17. The pattern of acoustic emission under fluid initiation of failure: Laboratory modeling

    NASA Astrophysics Data System (ADS)

    Potanina, M. G.; Smirnov, V. B.; Ponomarev, A. V.; Bernard, P.; Lyubushin, A. A.; Shoziyoev, Sh. P.

    2015-03-01

    The results of the laboratory experiment on the initiation of acoustic emission in a loaded specimen by wetting a part of its surface without a material increase in the pore pressure are analyzed. The experiment was conducted on the lever press at the Schmidt Institute of Physics of the Earth, Russian Academy of Sciences (Sobolev and Ponomarev, 2011). Infusion of water into the surface of the specimen initiated the swarm acoustic emission, which, after having migrated to the area with higher stresses, culminated in the formation of a macrofracture. The analysis revealed the regularities in the excitation and relaxation of the acoustic activity in response to different types of initiation: the forced excitation by stepwise increasing the load at the initial stage of the experiment; excitation resulting from fluid diffusion, which can be associated with the reduction in the material strength due to wetting; excitation that reflects the preparation for the emergence of a macrofracture in the area with the highest Coulomb stresses; and spontaneous excitation of swarm activity at the stage of relaxation of the acoustic emission after the formation of a macrofracture. The features revealed in the acoustic time series at the stages of excitation and decay of the emission are qualitatively similar to the trends identified in the variations of seismic parameters during the natural swarms, preparation of the sources of the strong earthquakes, and relaxation of the aftershocks. In particular, the obtained results support the hypothesis of fluid initiation of nonvolcanic seismic swarms.

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

    USGS Publications Warehouse

    Hayden, Todd A.; Holbrook, Christopher; 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.

  19. a Three-Step Spatial-Temporal Clustering Method for Human Activity Pattern Analysis

    NASA Astrophysics Data System (ADS)

    Huang, W.; Li, S.; Xu, S.

    2016-06-01

    How people move in cities and what they do in various locations at different times form human activity patterns. Human activity pattern plays a key role in in urban planning, traffic forecasting, public health and safety, emergency response, friend recommendation, and so on. Therefore, scholars from different fields, such as social science, geography, transportation, physics and computer science, have made great efforts in modelling and analysing human activity patterns or human mobility patterns. One of the essential tasks in such studies is to find the locations or places where individuals stay to perform some kind of activities before further activity pattern analysis. In the era of Big Data, the emerging of social media along with wearable devices enables human activity data to be collected more easily and efficiently. Furthermore, the dimension of the accessible human activity data has been extended from two to three (space or space-time) to four dimensions (space, time and semantics). More specifically, not only a location and time that people stay and spend are collected, but also what people "say" for in a location at a time can be obtained. The characteristics of these datasets shed new light on the analysis of human mobility, where some of new methodologies should be accordingly developed to handle them. Traditional methods such as neural networks, statistics and clustering have been applied to study human activity patterns using geosocial media data. Among them, clustering methods have been widely used to analyse spatiotemporal patterns. However, to our best knowledge, few of clustering algorithms are specifically developed for handling the datasets that contain spatial, temporal and semantic aspects all together. In this work, we propose a three-step human activity clustering method based on space, time and semantics to fill this gap. One-year Twitter data, posted in Toronto, Canada, is used to test the clustering-based method. The results show that the

  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.

  1. Analysis of Spatio-Temporal Traffic Patterns Based on Pedestrian Trajectories

    NASA Astrophysics Data System (ADS)

    Busch, S.; Schindler, T.; Klinger, T.; Brenner, C.

    2016-06-01

    For driver assistance and autonomous driving systems, it is essential to predict the behaviour of other traffic participants. Usually, standard filter approaches are used to this end, however, in many cases, these are not sufficient. For example, pedestrians are able to change their speed or direction instantly. Also, there may be not enough observation data to determine the state of an object reliably, e.g. in case of occlusions. In those cases, it is very useful if a prior model exists, which suggests certain outcomes. For example, it is useful to know that pedestrians are usually crossing the road at a certain location and at certain times. This information can then be stored in a map which then can be used as a prior in scene analysis, or in practical terms to reduce the speed of a vehicle in advance in order to minimize critical situations. In this paper, we present an approach to derive such a spatio-temporal map automatically from the observed behaviour of traffic participants in everyday traffic situations. In our experiments, we use one stationary camera to observe a complex junction, where cars, public transportation and pedestrians interact. We concentrate on the pedestrians trajectories to map traffic patterns. In the first step, we extract trajectory segments from the video data. These segments are then clustered in order to derive a spatial model of the scene, in terms of a spatially embedded graph. In the second step, we analyse the temporal patterns of pedestrian movement on this graph. We are able to derive traffic light sequences as well as the timetables of nearby public transportation. To evaluate our approach, we used a 4 hour video sequence. We show that we are able to derive traffic light sequences as well as time tables of nearby public transportation.

  2. Spatial and temporal patterns of exhumation across the Venezuelan Andes: Implications for Cenozoic Caribbean geodynamics

    NASA Astrophysics Data System (ADS)

    Bermúdez, Mauricio A.; Kohn, Barry P.; van der Beek, Peter A.; Bernet, Matthias; O'Sullivan, Paul B.; Shagam, Reginald

    2010-10-01

    The Venezuelan Andes formed by complex geodynamic interaction between the Caribbean Plate, the Panamá Arc, the South American Plate and the continental Maracaibo block. We study the spatial and temporal patterns of exhumation across the Venezuelan Andes using 47 new apatite fission track (AFT) ages as well as topographic analyses. This approach permits the identification of at least seven tectonic blocks (Escalante, Cerro Azul, Trujillo, Caparo, Sierra Nevada, Sierra La Culata and El Carmen blocks) with contrasting exhumation and cooling histories. The Sierra Nevada, Sierra La Culata and El Carmen blocks, located in the central part of the Venezuelan Andes and separated by the Boconó fault system, cooled rapidly but diachronously during the late Miocene-Pliocene. Major surface uplift and exhumation occurred in the Sierra Nevada block since before 8 Ma. A second phase of uplift and exhumation affected the El Carmen and Sierra La Culata blocks to the north of the Boconó fault during the late Miocene-Pliocene. The highest topography and steepest relief of the belt coincides with these blocks. The Caparo and Trujillo blocks, located at the northeastern and southwestern ends of the orogen, cooled more slowly from the Oligocene to the late Miocene. These blocks are characterized by significantly lower mean elevations and slightly lower mean slopes than the central blocks. Unraveling the cooling history of the individual blocks is important to better understand the control of preexisting faults and regional Caribbean geodynamics on the evolution of the Venezuelan Andes. Our data indicate a strong control of major preexisting fault zones on exhumation patterns and temporal correlation between phases of rapid exhumation in different blocks with major tectonic events (e.g., collision of the Panamá arc; rotation of the Maracaibo block).

  3. Temporal variability in winter travel patterns of Yellowstone bison: the effects of road grooming.

    PubMed

    Bruggeman, Jason E; Garrott, Robert A; Bjornlie, Daniel D; White, P J; Watson, Fred G R; Borkowski, John

    2006-08-01

    The influence of winter recreation on wildlife in Yellowstone National Park (YNP), Wyoming and Montana, USA, is a controversial issue. In particular, the effects of road grooming, done to facilitate snowmobile and snowcoach travel, on bison (Bison bison) ecology are under debate. We collected data during winters, from 1997 to 2005, on bison road use, off-road travel, and activity budgets to quantify temporal trends in the amount of bison road and off-road travel and to identify the ecological factors affecting bison movements and use of the groomed road system in the Madison-Gibbon-Firehole (MGF) area of YNP. Using model comparison techniques, we found bison travel patterns to be influenced by multiple, interacting effects. Road travel was negatively correlated with road grooming, and we found no evidence that bison preferentially used groomed roads during winter. Snow water equivalent, bison density, and the springtime melt period were positively correlated with both bison road and off-road travel. From behavioral scans on 68,791 bison, we found that travel is only a small percentage (11%) of all bison activity, with foraging comprising 67% of observations. Also, only 7% of traveling bison and 30% of foraging bison were displacing snow, and we suggest foraging, rather than traveling, is likely the major energetic cost to bison in winter. Bison utilize their own trail network, connecting foraging areas using stream corridors, geothermal pathways, and self-groomed travel routes. Our results indicate that temporal patterns in bison road travel are a manifestation of general travel behavior and that groomed roads in the MGF do not appear to be a major factor influencing bison ecology and spatial redistribution. We suggest that the changes in bison spatial dynamics during the past three decades have likely been the result of the natural phenomenon of density-dependent range expansion, rather than having been caused by the anthropogenic influence of road grooming.

  4. Using dynamic Brownian bridge movement modelling to measure temporal patterns of habitat selection.

    PubMed

    Byrne, Michael E; Clint McCoy, J; Hinton, Joseph W; Chamberlain, Michael J; Collier, Bret A

    2014-09-01

    Accurately describing animal space use is vital to understanding how wildlife use habitat. Improvements in GPS technology continue to facilitate collection of telemetry data at high spatial and temporal resolutions. Application of the recently introduced dynamic Brownian bridge movement model (dBBMM) to such data is promising as the method explicitly incorporates the behavioural heterogeneity of a movement path into the estimated utilization distribution (UD). Utilization distributions defining space use are normally estimated for time-scales ranging from weeks to months, obscuring much of the fine-scale information available from high-volume GPS data sets. By accounting for movement heterogeneity, the dBBMM provides a rigorous, behaviourally based estimate of space use between each set of relocations. Focusing on UDs generated between individual sets of locations allows us to quantify fine-scale circadian variation in habitat use. We used the dBBMM to estimate UDs bounding individual time steps for three terrestrial species with different life histories to illustrate how the method can be used to identify fine-scale variations in habitat use. We also demonstrate how dBBMMs can be used to characterize circadian patterns of habitat selection and link fine-scale patterns of habitat use to behaviour. We observed circadian patterns of habitat use that varied seasonally for a white-tailed deer (Odocoileus virginianus) and coyote (Canis latrans). We found seasonal patterns in selection by the white-tailed deer and were able to link use of conifer forests and agricultural fields to behavioural state of the coyote. Additionally, we were able to quantify the date in which a Rio Grande wild turkey (Meleagris gallopavo intermedia) initiated laying as well as when during the day, she was most likely to visit the nest site to deposit eggs. The ability to quantify circadian patterns of habitat use may have important implications for research and management of wildlife

  5. Passive acoustic telemetry reveals highly variable home range and movement patterns among unicornfish within a marine reserve

    NASA Astrophysics Data System (ADS)

    Marshell, A.; Mills, J. S.; Rhodes, K. L.; McIlwain, J.

    2011-09-01

    Marine reserves are the primary management tool for Guam's reef fish fishery. While a build-up of fish biomass has occurred inside reserve boundaries, it is unknown whether reserve size matches the scale of movement of target species. Using passive acoustic telemetry, we quantified movement patterns and home range size of two heavily exploited unicornfish Naso unicornis and Naso lituratus. Fifteen fish ( N. unicornis: n = 7; N. lituratus: n = 4 male, n = 4 female) were fitted with internal acoustic tags and tracked continuously over four months within a remote acoustic receiver array located in a decade-old marine reserve. This approach provided robust estimates of unicornfish movement patterns and home range size. The mean home range of 3.2 ha for N. unicornis was almost ten times larger than that previously recorded from a three-week tracking study of the species in Hawaii. While N. lituratus were smaller in body size, their mean home range (6.8 ha) was over twice that of N. unicornis. Both species displayed strong site fidelity, particularly during nocturnal and crepuscular periods. Although there was some overlap, individual movement patterns and home range size were highly variable within species and between sexes. N. unicornis home range increased with body size, and only the three largest fish home ranges extended into the deeper outer reef slope beyond the shallow reef flat. Both Naso species favoured habitat dominated by corals. Some individuals made predictable daily crepuscular migrations between different locations or habitat types. There was no evidence of significant spillover from the marine reserve into adjacent fished areas. Strong site fidelity coupled with negligible spillover suggests that small-scale reserves, with natural habitat boundaries to emigration, are effective in protecting localized unicornfish populations.

  6. Acoustic dose and acoustic dose-rate.

    PubMed

    Duck, Francis

    2009-10-01

    Acoustic dose is defined as the energy deposited by absorption of an acoustic wave per unit mass of the medium supporting the wave. Expressions for acoustic dose and acoustic dose-rate are given for plane-wave conditions, including temporal and frequency dependencies of energy deposition. The relationship between the acoustic dose-rate and the resulting temperature increase is explored, as is the relationship between acoustic dose-rate and radiation force. Energy transfer from the wave to the medium by means of acoustic cavitation is considered, and an approach is proposed in principle that could allow cavitation to be included within the proposed definitions of acoustic dose and acoustic dose-rate.

  7. Large-Scale Spatio-Temporal Patterns of Mediterranean Cephalopod Diversity

    PubMed Central

    Keller, Stefanie; Bartolino, Valerio; Hidalgo, Manuel; Bitetto, Isabella; Casciaro, Loredana; Cuccu, Danila; Esteban, Antonio; Garcia, Cristina; Garofalo, Germana; Josephides, Marios; Jadaud, Angelique; Lefkaditou, Evgenia; Maiorano, Porzia; Manfredi, Chiara; Marceta, Bojan; Massutí, Enric; Micallef, Reno; Peristeraki, Panagiota; Relini, Giulio; Sartor, Paolo; Spedicato, Maria Teresa; Tserpes, George; Quetglas, Antoni

    2016-01-01

    Species diversity is widely recognized as an important trait of ecosystems’ functioning and resilience. Understanding the causes of diversity patterns and their interaction with the environmental conditions is essential in order to effectively assess and preserve existing diversity. While diversity patterns of most recurrent groups such as fish are commonly studied, other important taxa such as cephalopods have received less attention. In this work we present spatio-temporal trends of cephalopod diversity across the entire Mediterranean Sea during the last 19 years, analysing data from the annual bottom trawl survey MEDITS conducted by 5 different Mediterranean countries using standardized gears and sampling protocols. The influence of local and regional environmental variability in different Mediterranean regions is analysed applying generalized additive models, using species richness and the Shannon Wiener index as diversity descriptors. While the western basin showed a high diversity, our analyses do not support a steady eastward decrease of diversity as proposed in some previous studies. Instead, high Shannon diversity was also found in the Adriatic and Aegean Seas, and high species richness in the eastern Ionian Sea. Overall diversity did not show any consistent trend over the last two decades. Except in the Adriatic Sea, diversity showed a hump-shaped trend with depth in all regions, being highest between 200–400 m depth. Our results indicate that high Chlorophyll a concentrations and warmer temperatures seem to enhance species diversity, and the influence of these parameters is stronger for richness than for Shannon diversity. PMID:26760965

  8. 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

  9. Temporal patterns and processes of retreat of drumlin coastal cliffs — Strangford Lough, Northern Ireland

    NASA Astrophysics Data System (ADS)

    Greenwood, Richard O.; Orford, Julian D.

    2008-02-01

    Monthly measurements of erosion pins at sixteen sites around the very low energy marine environment of Strangford Lough, Northern Ireland, were used to investigate temporal patterns and processes of retreat of low cliffs of glacial material. Erosion rates were extremely varied: the mean was 76 ± 49.03 mm a - 1 . Erosion is strongly seasonal with 86.6% of the total erosion occurring during 'winter' (September to March) periods. This seasonal pattern was most exaggerated in some of the more rapidly-eroding sites on the exposed eastern side of the lough. 'Preparatory processes' - heavy rainfall, desiccation and frost action - reduce the compressive strength of the cliff materials and act as important forcing of the erodibility of the cliffs. Direct wave attack on cliffs around the lough takes place when threshold conditions of wind speed and tidal heights are met (tidal levels > 1.50 m above O.D. with wind speed of 15.4 m s - 1 (30 knots), maintaining for more than 4 h). During the study period eighteen events exceeding the above criteria were identified. Extremely low atmospheric pressure has also been identified as important in raising water levels. Slumps, falls, topples and slides were the forms of cliff failure observed.

  10. 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.

  11. Detection of Cardiac Function Abnormality from MRI Images Using Normalized Wall Thickness Temporal Patterns.

    PubMed

    Wael, Mai; Ibrahim, El-Sayed H; Fahmy, Ahmed S

    2016-01-01

    Purpose. To develop a method for identifying abnormal myocardial function based on studying the normalized wall motion pattern during the cardiac cycle. Methods. The temporal pattern of the normalized myocardial wall thickness is used as a feature vector to assess the cardiac wall motion abnormality. Principal component analysis is used to reduce the feature dimensionality and the maximum likelihood method is used to differentiate between normal and abnormal features. The proposed method was applied on a dataset of 27 cases from normal subjects and patients. Results. The developed method achieved 81.5%, 85%, and 88.5% accuracy for identifying abnormal contractility in the basal, midventricular, and apical slices, respectively. Conclusions. A novel feature vector, namely, the normalized wall thickness, has been introduced for detecting myocardial regional wall motion abnormality. The proposed method provides assessment of the regional myocardial contractility for each cardiac segment and slice; therefore, it could be a valuable tool for automatic and fast determination of regional wall motion abnormality from conventional cine MRI images.

  12. Does sex matter? Temporal and spatial patterns of cougar-human conflict in British Columbia.

    PubMed

    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.

  13. Temporal patterns in count-to-ten fetal movement charts and their associations with pregnancy characteristics: a prospective cohort study

    PubMed Central

    2012-01-01

    Background Fetal movement counting has long been suggested as a screening tool to identify impaired placental function. However, quantitative limits for decreased fetal movement perform poorly for screening purposes, indicating the need for methodological refinement. We aimed to identify the main individual temporal patterns in fetal movement counting charts, and explore their associations with pregnancy characteristics. Methods In a population-based prospective cohort in Norway, 2009–2011, women with singleton pregnancies counted fetal movements daily from pregnancy week 24 until delivery using a modified "count-to-ten” procedure. To account for intra-woman correlation of observations, we used functional data analysis and corresponding functional principal component analysis to identify the main individual temporal patterns in fetal movement count data. The temporal patterns are described by continuous functional principal component (FPC) curves, with an individual score on each FPC for each woman. These scores were later used as outcome variables in multivariable linear regression analyses, with pregnancy characteristics as explanatory variables. Results Fetal movement charts from 1086 pregnancies were included. Three FPC curves explained almost 99% of the variation in the temporal data, with the first FPC, representing the individual overall counting time, accounting for 91% alone. There were several statistically significant associations between the FPCs and various pregnancy characteristics. However, the effects were small and of limited clinical value. Conclusions This statistical approach for analyzing fetal movement counting data successfully captured clinically meaningful individual temporal patterns and how these patterns vary between women. Maternal body mass index, gestational age and placental site explained little of the variation in the temporal fetal movement counting patterns. Thus, a perceived decrease in fetal movement should not be

  14. 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.

  15. Patterns of Occurrence and Marine Mammal Acoustic Behavior in Relation to Navy Sonar Activity Off Jacksonville, Florida.

    PubMed

    Oswald, Julie N; Norris, Thomas F; Yack, Tina M; Ferguson, Elizabeth L; Kumar, Anurag; Nissen, Jene; Bell, Joel

    2016-01-01

    Passive acoustic data collected from marine autonomous recording units deployed off Jacksonville, FL (from 13 September to 8 October 2009 and 3 December 2009 to 8 January 2010), were analyzed for detection of cetaceans and Navy sonar. Cetaceans detected included Balaenoptera acutorostrata, Eubalaena glacialis, B. borealis, Physeter macrocephalus, blackfish, and delphinids. E. glacialis were detected at shallow and, somewhat unexpectedly, deep sites. P. macrocephalus were characterized by a strong diel pattern. B. acutorostrata showed the strongest relationship between sonar activity and vocal behavior. These results provide a preliminary assessment of cetacean occurrence off Jacksonville and new insights on vocal responses to sonar.

  16. Multi-instrument Method to Map Spatial and Temporal Patterns of Snowmelt Infiltration

    NASA Astrophysics Data System (ADS)

    Hyde, K.; Beverly, D.; Thayer, D.; Speckman, H. N.; Parsekian, A.; Kelleners, T.

    2015-12-01

    Mapping spatial patterns of relative soil moisture over time may improve understanding of snowmelt infiltration processes in heterogeneous systems. Conventional soil water measurement methods disturb soil properties and rocky materials generally limit installation of monitoring instruments to shallow depths in mountainous landscapes with snowmelt dominated hydrology. Modifications to existing technology combined with low impact installation methods provide high temporal and spatial resolution of relative soil moisture as well as a temperature profile and water table level. Closely spaced (10cm) electrical resistance pads are combined in a small diameter (2.54 cm) tube with temperature probes each 50cm, a pressure transducer, and a tube to extract groundwater for stable isotope analysis. This vertical probe array (VPA) extends 3.2m and is installed in a small diameter (4 cm) bore using a backpack drill limiting soil disturbance. Two VPAs are installed in the Snowy Range of Wyoming, one in a forested mountainous environment impacted by mortality by insects and disease and the other (limited to resistance pads only) in recently burned sagelands. Each VPA is co-located with meteorological stations. Eddy-covariance, sap flux, electrical resistivity, snowpack survey, and other hillslope eco-hydrology measurements accompany the fully instrumented VPA. Data are sampled and recorded at 5 or 15 minute intervals starting in December 2014. Over the winter both sites exhibit highly variable patterns of relatively dry soils with steady increase in wetness. Abrupt increases in relative wetness occurred with short periods of warming temperatures in Spring. Following a temperature increase in the forested site the relative moisture dramatically increased over a period of several hours at all depths as water level rose 1m within 8 hours. In contrast, following snowmelt relative moisture in the sageland site increased gradually and systematically with depth over a period of two weeks

  17. 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.

  18. Spontaneous assembly of chemically encoded two-dimensional coacervate droplet arrays by acoustic wave patterning

    PubMed Central

    Tian, Liangfei; Martin, Nicolas; Bassindale, Philip G.; Patil, Avinash J.; Li, Mei; Barnes, Adrian; Drinkwater, Bruce W.; Mann, Stephen

    2016-01-01

    The spontaneous assembly of chemically encoded, molecularly crowded, water-rich micro-droplets into periodic defect-free two-dimensional arrays is achieved in aqueous media by a combination of an acoustic standing wave pressure field and in situ complex coacervation. Acoustically mediated coalescence of primary droplets generates single-droplet per node micro-arrays that exhibit variable surface-attachment properties, spontaneously uptake dyes, enzymes and particles, and display spatial and time-dependent fluorescence outputs when exposed to a reactant diffusion gradient. In addition, coacervate droplet arrays exhibiting dynamical behaviour and exchange of matter are prepared by inhibiting coalescence to produce acoustically trapped lattices of droplet clusters that display fast and reversible changes in shape and spatial configuration in direct response to modulations in the acoustic frequencies and fields. Our results offer a novel route to the design and construction of ‘water-in-water' micro-droplet arrays with controllable spatial organization, programmable signalling pathways and higher order collective behaviour. PMID:27708286

  19. 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...

  20. Spontaneous assembly of chemically encoded two-dimensional coacervate droplet arrays by acoustic wave patterning

    NASA Astrophysics Data System (ADS)

    Tian, Liangfei; Martin, Nicolas; Bassindale, Philip G.; Patil, Avinash J.; Li, Mei; Barnes, Adrian; Drinkwater, Bruce W.; Mann, Stephen

    2016-10-01

    The spontaneous assembly of chemically encoded, molecularly crowded, water-rich micro-droplets into periodic defect-free two-dimensional arrays is achieved in aqueous media by a combination of an acoustic standing wave pressure field and in situ complex coacervation. Acoustically mediated coalescence of primary droplets generates single-droplet per node micro-arrays that exhibit variable surface-attachment properties, spontaneously uptake dyes, enzymes and particles, and display spatial and time-dependent fluorescence outputs when exposed to a reactant diffusion gradient. In addition, coacervate droplet arrays exhibiting dynamical behaviour and exchange of matter are prepared by inhibiting coalescence to produce acoustically trapped lattices of droplet clusters that display fast and reversible changes in shape and spatial configuration in direct response to modulations in the acoustic frequencies and fields. Our results offer a novel route to the design and construction of `water-in-water' micro-droplet arrays with controllable spatial organization, programmable signalling pathways and higher order collective behaviour.

  1. Rationalizing spatial exploration patterns of wild animals and humans through a temporal discounting framework

    PubMed Central

    Namboodiri, Vijay Mohan K.; Levy, Joshua M.; Mihalas, Stefan; Sims, David W.; Hussain Shuler, Marshall G.

    2016-01-01

    Understanding the exploration patterns of foragers in the wild provides fundamental insight into animal behavior. Recent experimental evidence has demonstrated that path lengths (distances between consecutive turns) taken by foragers are well fitted by a power law distribution. Numerous theoretical contributions have posited that “Lévy random walks”—which can produce power law path length distributions—are optimal for memoryless agents searching a sparse reward landscape. It is unclear, however, whether such a strategy is efficient for cognitively complex agents, from wild animals to humans. Here, we developed a model to explain the emergence of apparent power law path length distributions in animals that can learn about their environments. In our model, the agent’s goal during search is to build an internal model of the distribution of rewards in space that takes into account the cost of time to reach distant locations (i.e., temporally discounting rewards). For an agent with such a goal, we find that an optimal model of exploration in fact produces hyperbolic path lengths, which are well approximated by power laws. We then provide support for our model by showing that humans in a laboratory spatial exploration task search space systematically and modify their search patterns under a cost of time. In addition, we find that path length distributions in a large dataset obtained from free-ranging marine vertebrates are well described by our hyperbolic model. Thus, we provide a general theoretical framework for understanding spatial exploration patterns of cognitively complex foragers. PMID:27385831

  2. Spatial and Temporal Patterns of Dissolved Organic Matter Characteristics in the Upper Willamette River Basin, Oregon

    NASA Astrophysics Data System (ADS)

    Lee, B. S.; Lajtha, K.

    2014-12-01

    Dissolved organic matter (DOM) leaching through soil affects soil carbon sequestration and the carbon metabolism of receiving water bodies. Improving our understanding of the sources and fate of DOM at varying spatial and temporal patterns is crucial for land management decisions. However, little is known about how DOM sources change with land use types and seasonal flow patterns. In the Willamette River Basin (WRB), which is home to Oregon's major cities including Portland and Salem, forested headwaters transition to agricultural and urban land. The climate of WRB has a distinctive seasonal pattern with dry warm summers and wet winters driven by winter precipitation and snowmelt runoff between November and March. This study examined DOM fluorescence characteristic in stream water from 21 locations collected monthly and 16 locations collected seasonally to identify the sources and fate of DOM in the upper WRB in contrasting land uses. DOC and dissolved organic nitrogen concentrations increased as the flow rate increased during winter precipitation at all sites. This indicates that increased flow rate increased the connectivity between land and nearby water bodies. DOM fluorescent properties varied among land use types. During the first precipitation event after a long dry summer, a microbial DOM signature in agricultural areas increased along with nitrate concentrations. This may be because accumulated nutrients on land during the dry season flowed to nearby streams during the first rain event and promoted microbial growth in the streams. During the month of the highest flow rate in 2014, sampling sites near forest showed evidence of a greater terrestrial DOM signature compared to its signature during the dry season. This indicates fluorescent DOM characteristics in streams vary as the flow connectivity changes even within the same land type.

  3. Vertical distribution, composition and migratory patterns of acoustic scattering layers in the Canary Islands

    NASA Astrophysics Data System (ADS)

    Ariza, A.; Landeira, J. M.; Escánez, A.; Wienerroither, R.; Aguilar de Soto, N.; Røstad, A.; Kaartvedt, S.; Hernández-León, S.

    2016-05-01

    Diel vertical migration (DVM) facilitates biogeochemical exchanges between shallow waters and the deep ocean. An effective way of monitoring the migrant biota is by acoustic observations although the interpretation of the scattering layers poses challenges. Here we combine results from acoustic observations at 18 and 38 kHz with limited net sampling in order to unveil the origin of acoustic phenomena around the Canary Islands, subtropical northeast Atlantic Ocean. Trawling data revealed a high diversity of fishes, decapods and cephalopods (152 species), although few dominant species likely were responsible for most of the sound scattering in the region. We identified four different acoustic scattering layers in the mesopelagic realm: (1) at 400-500 m depth, a swimbladder resonance phenomenon at 18 kHz produced by gas-bearing migrant fish such as Vinciguerria spp. and Lobianchia dofleini, (2) at 500-600 m depth, a dense 38 kHz layer resulting primarily from the gas-bearing and non-migrant fish Cyclothone braueri, and to a lesser extent, from fluid-like migrant fauna also inhabiting these depths, (3) between 600 and 800 m depth, a weak signal at both 18 and 38 kHz ascribed either to migrant fish or decapods, and (4) below 800 m depth, a weak non-migrant layer at 18 kHz which was not sampled. All the dielly migrating layers reached the epipelagic zone at night, with the shorter-range migrations moving at 4.6 ± 2.6 cm s - 1 and the long-range ones at 11.5 ± 3.8 cm s - 1. This work reduces uncertainties interpreting standard frequencies in mesopelagic studies, while enhances the potential of acoustics for future research and monitoring of the deep pelagic fauna in the Canary Islands.

  4. 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

  5. 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.

  6. Laser-speckle-visibility acoustic spectroscopy in soft turbid media

    NASA Astrophysics Data System (ADS)

    Wintzenrieth, Frédéric; Cohen-Addad, Sylvie; Le Merrer, Marie; Höhler, Reinhard

    2014-01-01

    We image the evolution in space and time of an acoustic wave propagating along the surface of turbid soft matter by shining coherent light on the sample. The wave locally modulates the speckle interference pattern of the backscattered light, which is recorded using a camera. We show both experimentally and theoretically how the temporal and spatial correlations in this pattern can be analyzed to obtain the acoustic wavelength and attenuation length. The technique is validated using shear waves propagating in aqueous foam. It may be applied to other kinds of acoustic waves in different forms of turbid soft matter such as biological tissues, pastes, or concentrated emulsions.

  7. Earthquake damage history in Israel and its close surrounding - evaluation of spatial and temporal patterns

    NASA Astrophysics Data System (ADS)

    Zohar, Motti; Salamon, Amos; Rubin, Rehav

    2017-01-01

    Israel was hit by destructive earthquakes many times in the course of history. To properly understand the hazard and support effective preparedness towards future earthquakes, we examined the spatial and temporal distribution of the resulted damage. We described in detail our systematic approach to searching the available literature, collecting the data and screening the authenticity of that information. We used GIS (Geographic Information System) to map and evaluate the distribution of the damage and to search for recurring patterns. Overall, it is found that 186 localities were hit, 54 of them at least twice. We also found that Israel was affected by 4, 17, 8 and 2 damaging earthquakes that originated, respectively, from the southern, central, central-northern and northern parts of the Dead Sea Transform (DST). The temporal appearance of the northern earthquakes is clustered; the central earthquakes are more regular in time, whereas no damage from the north-central and the central quakes, with the exception of the year 363 earthquake, seems to have occurred south of the Dead Sea region. Analyzing the distribution of the damage, we realized that the number of the damage reports reflects only half of the incidents that actually happened, attesting to incompleteness of the historical catalogue. Jerusalem is the most reported city with 14 entries, followed by Akko (Acre), Tiberias, Nablus and Tyre with 8, 7, 7 and 6 reports, respectively. In general, localities in the Galilee and north of it suffered more severely than localities in central Israel with the exception of Nablus and the localities along the coastal plain of Israel, most probably due to local site effects. For the sake of hazard management, these observations should be considered for future planning and risk mitigation.

  8. Factors controlling spatial and temporal patterns of multiple pesticide compounds in groundwater (Hesbaye chalk aquifer, Belgium).

    PubMed

    Hakoun, Vivien; Orban, Philippe; Dassargues, Alain; Brouyère, Serge

    2017-04-01

    Factors governing spatial and temporal patterns of pesticide compounds (pesticides and metabolites) concentrations in chalk aquifers remain unclear due to complex flow processes and multiple sources. To uncover which factors govern pesticide compound concentrations in a chalk aquifer, we develop a methodology based on time series analyses, uni- and multivariate statistics accounting for concentrations below detection limits. The methodology is applied to long records (1996-2013) of a restricted compound (bentazone), three banned compounds (atrazine, diuron and simazine) and two metabolites (deethylatrazine (DEA) and 2,6-dichlorobenzamide (BAM)) sampled in the Hesbaye chalk aquifer in Belgium. In the confined area, all compounds had non-detects fractions >80%. By contrast, maximum concentrations exceeded EU's drinking-water standard (100 ng L(-1)) in the unconfined area. This contrast confirms that recent recharge and polluted water did not reach the confined area, yet. Multivariate analyses based on variables representative of the hydrogeological setting revealed higher diuron and simazine concentrations in the southeast of the unconfined area, where urban activities dominate land use and where the aquifer lacks protection from a less permeable layer of hardened chalk. At individual sites, positive correlations (up to τ=0.48 for bentazone) between pesticide compound concentrations and multi-annual groundwater level fluctuations confirm occurrences of remobilization. A downward temporal trend of atrazine concentrations likely reflects decreasing use of this compound over the last 28 years. However, the lack of a break in concentrations time series and maximum concentrations of atrazine, simazine, DEA and BAM exceeding EU's standard post-ban years provide evidence of persistence. Contrasting upward trends in bentazone concentrations show that a time lag is required for restriction measures to be efficient. These results shed light on factors governing pesticide

  9. 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 γ-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 γ-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

  10. Temporal and spatial patterns of West Nile virus transmission in Saginaw County, Michigan, 2003-2006.

    PubMed

    Chuang, Ting-Wu; Knepper, Randall G; Stanuszek, William W; Walker, Edward D; Wilson, Mark L

    2011-09-01

    The dynamics of West Nile virus (family Flaviviridae, genus Flavivirus, WNV) infection in mosquitoes, sentinel pheasants, and wild dead birds were evaluated during 2003-2006 in Saginaw Co., MI. Mosquitoes were collected by New Jersey Light Traps at 22 sites during May-September, pooled by species and sample location, and tested for presence of WNV RNA by using a real-time reverse transcription-polymerase chain reaction assay. Oral swabs from wild dead birds submitted by the public were tested by Vec-Test assay. Sentinel pheasants were bled weekly, and serum was tested for antibodies with an inhibition enzyme immunoassay. In total, 37,225 mosquitoes [Aedes vexans (Meigen), Culex pipiens L., and Culex restuans Theobald] were tested in 5,429 pools, of which 59 (1.1%) were positive. Ae. vexans was most abundant but had a comparatively low infection rate (0.06-2.11) compared with Cx. pipiens (1.75-4.59) and Cx. restuans (1.22-15.67). Mosquito abundances were temporally related to variations in 2-wk average weather variables. Infected dead crows appeared earlier each transmission season than blue jays, but infection prevalence for both peaked approximately mid-August. Space-time clusters were found in different locations each year. Sentinel pheasant seroprevalence was 19.3% (16/83), 12.7% (10/79), and 7.7% (5/65) during 2003-2005, respectively. We demonstrated temporal patterns of WNV activity in corvid birds and Culex spp. mosquitoes during the study period, suggesting virus transmission within an enzootic cycle. Despite the absence of human case reports nearby, this surveillance system demonstrated WNV transmission and possible human risk. Maintained surveillance using more appropriate gravid traps and CDC CO2 light traps could improve sensitivity of vector collection and virus detection.

  11. 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

  12. Mining Spatial-Temporal Patterns and Structural Sparsity for Human Motion Data Denoising.

    PubMed

    Feng, Yinfu; Ji, Mingming; Xiao, Jun; Yang, Xiaosong; Zhang, Jian J; Zhuang, Yueting; Li, Xuelong

    2015-12-01

    Motion capture is an important technique with a wide range of applications in areas such as computer vision, computer animation, film production, and medical rehabilitation. Even with the professional motion capture systems, the acquired raw data mostly contain inevitable noises and outliers. To denoise the data, numerous methods have been developed, while this problem still remains a challenge due to the high complexity of human motion and the diversity of real-life situations. In this paper, we propose a data-driven-based robust human motion denoising approach by mining the spatial-temporal patterns and the structural sparsity embedded in motion data. We first replace the regularly used entire pose model with a much fine-grained partlet model as feature representation to exploit the abundant local body part posture and movement similarities. Then, a robust dictionary learning algorithm is proposed to learn multiple compact and representative motion dictionaries from the training data in parallel. Finally, we reformulate the human motion denoising problem as a robust structured sparse coding problem in which both the noise distribution information and the temporal smoothness property of human motion have been jointly taken into account. Compared with several state-of-the-art motion denoising methods on both the synthetic and real noisy motion data, our method consistently yields better performance than its counterparts. The outputs of our approach are much more stable than that of the others. In addition, it is much easier to setup the training dataset of our method than that of the other data-driven-based methods.

  13. Don't forget the porpoise: acoustic monitoring reveals fine scale temporal variation between bottlenose dolphin and harbour porpoise in Cardigan Bay SAC.

    PubMed

    Nuuttila, Hanna K; Courtene-Jones, Winnie; Baulch, Sarah; Simon, Malene; Evans, Peter G H

    2017-01-01

    Populations of bottlenose dolphin and harbour porpoise inhabit Cardigan Bay, which was designated a Special Area of Conservation (SAC), with bottlenose dolphin listed as a primary feature for its conservation status. Understanding the abundance, distribution and habitat use of species is fundamental for conservation and the implementation of management. Bottlenose dolphin and harbour porpoise usage of feeding sites within Cardigan Bay SAC was examined using passive acoustic monitoring. Acoustic detections recorded with calibrated T-PODs (acoustic data loggers) indicated harbour porpoise to be present year round and in greater relative abundance than bottlenose dolphin. Fine-scale temporal partitioning between the species occurred at three levels: (1) seasonal differences, consistent between years, with porpoise detections peaking in winter months and dolphin detections in summer months; (2) diel variation, consistent across sites, seasons and years, with porpoise detections highest at night and dolphin detections highest shortly after sunrise; and (3) tidal variation was observed with peak dolphin detections occurring during ebb at the middle of the tidal cycle and before low tide, whereas harbour porpoise detections were highest at slack water, during and after high water with a secondary peak recorded during and after low water. General Additive Models (GAMs) were applied to better understand the effects of each covariate. The reported abundance and distribution of the two species, along with the temporal variation observed, have implications for the design and management of protected areas. Currently, in the UK, no SACs have been formally designated for harbour porpoise while three exist for bottlenose dolphins. Here, we demonstrate a need for increased protection and species-specific mitigation measures for harbour porpoise.

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

    NASA Astrophysics Data System (ADS)

    Johnson, C. W.; Burgmann, R.

    2013-12-01

    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.

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

    PubMed

    Austin, Deborah; Bowen, W D; McMillan, J I; Boness, D J

    2006-03-01

    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 length varying from 2 to 40 days (mean: 16.33 +/- 2.67 days/seal). 3. Seals fed on 57.8 +/- 6.46% of days sampled and had an average of 1.7 +/- 0.26 meals per day, but individual variability was apparent in the temporal distribution of feeding as evidenced by high coefficients of variation (coefficient of variation = 69.0%). 4. Bout analysis of non-feeding intervals of six grey seals suggests that feeding intervals of individuals were varied and probably reflect differences in prey availability. Grey seals tended to have many single feeding events with long periods separating each event, as would be expected for a large carnivore with a batch-reactor digestive system. 5. We found significant sex differences in the temporal distribution of feeding. The number of feeding events per day was greater in males (2.2 +/- 0.4 vs. 1.0 +/- 0.2), as was time associated with feeding per day (56.6 +/- 5.8 min vs. 43.9 +/- 9.4 min). 6. The number of feeding events varied with time of day with the least number occurring during dawn. Feeding event size differed significantly by time of day, with greater meal sizes during the dawn and the smallest meals during the night. 7. The length of time between meals increased with the size of the previous meal, and was significantly less in males (541.4 +/- 63.5 min) than in females (1092.6 +/- 169.9 min). 8. These results provide new insight into the basis of sex differences in diving and diet in this large size-dimorphic marine predator.

  16. Understanding spatial and temporal patterning of astrocyte calcium transients via interactions between network transport and extracellular diffusion

    NASA Astrophysics Data System (ADS)

    Shtrahman, E.; Maruyama, D.; Olariu, E.; Fink, C. G.; Zochowski, M.

    2017-02-01

    Astrocytes form interconnected networks in the brain and communicate via calcium signaling. We investigate how modes of coupling between astrocytes influence the spatio-temporal patterns of calcium signaling within astrocyte networks and specifically how these network interactions promote coordination within this group of cells. To investigate these complex phenomena, we study reduced cultured networks of astrocytes and neurons. We image the spatial temporal patterns of astrocyte calcium activity and quantify how perturbing the coupling between astrocytes influences astrocyte activity patterns. To gain insight into the pattern formation observed in these cultured networks, we compare the experimentally observed calcium activity patterns to the patterns produced by a reduced computational model, where we represent astrocytes as simple units that integrate input through two mechanisms: gap junction coupling (network transport) and chemical release (extracellular diffusion). We examine the activity patterns in the simulated astrocyte network and their dependence upon these two coupling mechanisms. We find that gap junctions and extracellular chemical release interact in astrocyte networks to modulate the spatiotemporal patterns of their calcium dynamics. We show agreement between the computational and experimental findings, which suggests that the complex global patterns can be understood as a result of simple local coupling mechanisms.

  17. Muscle wasting and the temporal gene expression pattern in a novel rat intensive care unit model

    PubMed Central

    2011-01-01

    Background Acute quadriplegic myopathy (AQM) or critical illness myopathy (CIM) is frequently observed in intensive care unit (ICU) patients. To elucidate duration-dependent effects of the ICU intervention on molecular and functional networks that control the muscle wasting and weakness associated with AQM, a gene expression profile was analyzed at time points varying from 6 hours to 14 days in a unique experimental rat model mimicking ICU conditions, i.e., post-synaptically paralyzed, mechanically ventilated and extensively monitored animals. Results During the observation period, 1583 genes were significantly up- or down-regulated by factors of two or greater. A significant temporal gene expression pattern was constructed at short (6 h-4 days), intermediate (5-8 days) and long (9-14 days) durations. A striking early and maintained up-regulation (6 h-14d) of muscle atrogenes (muscle ring-finger 1/tripartite motif-containing 63 and F-box protein 32/atrogin-1) was observed, followed by an up-regulation of the proteolytic systems at intermediate and long durations (5-14d). Oxidative stress response genes and genes that take part in amino acid catabolism, cell cycle arrest, apoptosis, muscle development, and protein synthesis together with myogenic factors were significantly up-regulated from 5 to 14 days. At 9-14 d, genes involved in immune response and the caspase cascade were up-regulated. At 5-14d, genes related to contractile (myosin heavy chain and myosin binding protein C), regulatory (troponin, tropomyosin), developmental, caveolin-3, extracellular matrix, glycolysis/gluconeogenesis, cytoskeleton/sarcomere regulation and mitochondrial proteins were down-regulated. An activation of genes related to muscle growth and new muscle fiber formation (increase of myogenic factors and JunB and down-regulation of myostatin) and up-regulation of genes that code protein synthesis and translation factors were found from 5 to 14 days. Conclusions Novel temporal patterns of

  18. Decoding temporal structure in music and speech relies on shared brain resources but elicits different fine-scale spatial patterns.

    PubMed

    Abrams, Daniel A; Bhatara, Anjali; Ryali, Srikanth; Balaban, Evan; Levitin, Daniel J; Menon, Vinod

    2011-07-01

    Music and speech are complex sound streams with hierarchical rules of temporal organization that become elaborated over time. Here, we use functional magnetic resonance imaging to measure brain activity patterns in 20 right-handed nonmusicians as they listened to natural and temporally reordered musical and speech stimuli matched for familiarity, emotion, and valence. Heart rate variability and mean respiration rates were simultaneously measured and were found not to differ between musical and speech stimuli. Although the same manipulation of temporal structure elicited brain activation level differences of similar magnitude for both music and speech stimuli, multivariate classification analysis revealed distinct spatial patterns of brain responses in the 2 domains. Distributed neuronal populations that included the inferior frontal cortex, the posterior and anterior superior and middle temporal gyri, and the auditory brainstem classified temporal structure manipulations in music and speech with significant levels of accuracy. While agreeing with previous findings that music and speech processing share neural substrates, this work shows that temporal structure in the 2 domains is encoded differently, highlighting a fundamental dissimilarity in how the same neural resources are deployed.

  19. Saline Stress Alters the Temporal Patterns of Xylem Differentiation and Alternative Oxidase Expression in Developing Soybean Roots1

    PubMed Central

    Hilal, Mirna; Zenoff, Ana M.; Ponessa, Graciela; Moreno, Hortensia; Massa, Eddy M.

    1998-01-01

    We conducted a coordinated biochemical and morphometric analysis of the effect of saline conditions on the differentiation zone of developing soybean (Glycine max L.) roots. Between d 3 and d 14 for seedlings grown in control or NaCl-supplemented medium, we studied (a) the temporal evolution of the respiratory alternative oxidase (AOX) capacity in correlation with the expression and localization of AOX protein analyzed by tissue-print immunoblotting; (b) the temporal evolution and tissue localization of a peroxidase activity involved in lignification; and (c) the structural changes, visualized by light microscopy and quantified by image digitization. The results revealed that saline stress retards primary xylem differentiation. There is a corresponding delay in the temporal pattern of AOX expression, which is consistent with the xylem-specific localization of AOX protein and the idea that this enzyme is linked to xylem development. An NaCl-induced acceleration of the development of secondary xylem was also observed. However, the temporal pattern of a peroxidase activity localized in the primary and secondary xylem was unaltered by NaCl treatment. Thus, the NaCl-stressed root was specifically affected in the temporal patterns of AOX expression and xylem development. PMID:9625723

  20. ClinicalTime: Identification of Patients with Acute Kidney Injury using Temporal Abstractions and Temporal Pattern Matching

    PubMed Central

    Capurro, Daniel; Barbe, Mario; Daza, Claudio; María, Josefa Santa; Trincado, Javier; Gomez, Ignacio

    2015-01-01

    Introduction The rising cost of providing healthcare services creates an extreme pressure to know what works best in medicine. Traditional methods of generating clinical evidence are expensive and time consuming. The availability of electronic clinical data generated during routine patient encounters provides an opportunity to use that information to generate new clinical evidence. However, electronic clinical data is frequently marred by inadequate quality that impedes such secondary uses. This study provides a proof-of-concept and tests the classification accuracy of ClinicalTime—a temporal query system—to identify patient cohorts in clinical databases. Methods we randomly selected a sample of medical records from the MIMIC-II database, an anonymized database of intensive care patients. Records were manually classified as having an acute kidney injury or not according to the AKIN criteria. Those records were then blindly classified using ClinicalTime to represent the AKIN criteria. Classification accuracy was measured. Results ClinicalTime correctly classified 88% of all patients, with a sensitivity of 0.93 and specificity of 0.84. Its performance was superior to simply using ICD-9 codes, which correctly classified 66% of all patients. Conclusions ClinicalTime, a temporal query system, is a valid method to add to the currently available ones to identify patient phenotypes in patient databases and, thus, improving our ability to re-use routinely collected electronic clinical data for secondary purposes. PMID:26306233

  1. Acoustic pattern variations in the female-directed birdsongs of a colony of laboratory-bred zebra finches.

    PubMed

    Helekar; Marsh; Viswanath; Rosenfield

    2000-04-03

    The acoustic profile of the zebra finch song is characterized by a series of identical repeating units, each comprising a distinctive sequence of acoustic elements, called syllables. Here, we perform an analysis of song pattern deviations caused by variabilities in the production of song syllables. Zebra finches produce four different kinds of syllable variabilities-syllable deletions, single or double syllable insertions, syllable alterations, and syllable repetitions. All these variabilities, with the exception of repetitions, are present in songs of more than two-thirds of the normal adult birds; repetitions are present in less than one-fifth of birds. The frequency of occurrence of these variabilities is independent of the amount of singing, suggesting that they are unlikely to result simply from singing-induced physiological changes such as fatigue. Their frequencies in tutor-deprived birds are not significantly different from those in normal birds, indicating that they are unlikely to be acquired due to deficiencies in tutor-dependent learning. The types, patterns of occurrence and relative frequencies of these song syllable variabilities might reveal insights into the functioning of the song motor control pathway.

  2. Expression pattern of Mical-1 in the temporal neocortex of patients with intractable temporal epilepsy and pilocarpine-induced rat model.

    PubMed

    Luo, Jing; Xu, Yali; Zhu, Qiong; Zhao, Fenghua; Zhang, Ying; Peng, Xi; Wang, Wei; Wang, Xuefeng

    2011-11-01

    Mical-1 is a novel F-actin-disassembly factor that is critical in actin reorganization. It provides a molecular conduit through which actin reorganizes-a hallmark of cell morphological changes, including axon navigation. However, whether Mical-1 is involved in the epileptogenesis remains unknown. Here, we investigate Mical-1 expression pattern in patients with intractable temporal lobe epilepsy (TLE) and pilocarpine-induced rat model. We used double-labeled immunoflurescence, immunohistochemistry, and Western blotting to assess the location and expression of Mical-1 in temporal neocortex of patients with intractable TLE, and the expression pattern of Mical-1 at different time point in the hippocampus and temporal lobe cortex of the pilocarpine-induced rat model. Double-labeled immunofluorescence showed that Mical-1 was coexpressed with neuron-specific enolase (NSE) in the cytoplasm of neurons in temporal neocortex of patients with TLE and hippocampus of rat model. Faint and scattered immunoreactivity for Mical-1 in the neuron of temporal neocortex in TLE group, but strong immunoreactivity for Mical-1 was shown in control subjects. To quantitatively evaluate the Mical-1 immunoreactivity, we measured the mean optical density (OD) of Mical-1. In the hippocampus of pilocarpine-induced rat model, the OD values transient increased at 6 h after seizure then decreased from 1 day to 14 days, and returned to a subnormal level at 60 days. The lowest level of Mical-1 expression occurred at 14 days after seizure in the hippocampus. In the temporal lobe cortex of rat model, the OD values decreased at all time point after kindling compared to the normal group. Furthermore, our Western blot analysis confirmed these expression patterns of Mical-1 from latent stage to chronic stage. Our results indicate that in patients with TLE and pilocarpine-induced rat model, the expression of Mical-1 were followed a downtrend from the latent stage to chronic stage after seizure evoke. Thus, as

  3. Learning and Discrimination of Audiovisual Events in Human Infants: The Hierarchical Relation between Intersensory Temporal Synchrony and Rhythmic Pattern Cues.

    ERIC Educational Resources Information Center

    Lewkowicz, David J.

    2003-01-01

    Three experiments examined 4- to 10-month-olds' perception of audio-visual (A-V) temporal synchrony cues in the presence or absence of rhythmic pattern cues. Results established that infants of all ages could discriminate between two different audio-visual rhythmic events. Only 10-month-olds detected a desynchronization of the auditory and visual…

  4. Effects of Temporal Sequencing and Auditory Discrimination on Children's Memory Patterns for Tones, Numbers, and Nonsense Words

    ERIC Educational Resources Information Center

    Gromko, Joyce Eastlund; Hansen, Dee; Tortora, Anne Halloran; Higgins, Daniel; Boccia, Eric

    2009-01-01

    The purpose of this study was to determine whether children's recall of tones, numbers, and words was supported by a common temporal sequencing mechanism; whether children's patterns of memory for tones, numbers, and nonsense words were the same despite differences in symbol systems; and whether children's recall of tones, numbers, and nonsense…

  5. 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....

  6. 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...

  7. Spatial and temporal patterns of micropollutants in streams and effluent of 24 WWTPs across Switzerland

    NASA Astrophysics Data System (ADS)

    Schönenberger, Urs; Spycher, Barbara; Kistler, David; Burdon, Frank; Reyes, Marta; Eggen, Rik; Joss, Adriano; Singer, Heinz; Stamm, Christian

    2016-04-01

    Treated municipal wastewater is an important source of micropollutants entering the environment. Micropollutants are a diverse range of chemicals of which concentrations vary strongly in space and time. To better quantitatively understand the spatio-temporal patterns of micropollutants in streams, we compared upstream and downstream locations at 24 wastewater treatment plants (WWTPs) across the Swiss Plateau and Jura regions. Each site represents the most upstream treatment plant in the corresponding catchment. In 2013, a broad analytical screening was applied to samples collected at 12 sites during winter (January) and summer conditions (June). Based in these results, the bi-monthly samples obtained in 2014 at 12 additional sites were analysed for a group of approximately 60 selected organic micropollutants. The screening results demonstrate that generally, pharmaceuticals, artificial sweeteners and corrosion inhibitors make up the largest share of the organic micropollutants in wastewater. Pesticides including biocides and plant protection products are also regularly found, but at lower concentrations. The opposite holds true for the concentration variability: pesticides vary the most across time and space, while pharmaceuticals exhibit more stable concentrations. Heavy metals fluctuate to a similar degree as pharmaceuticals. Principal component analyses suggest that pesticide and pharmaceutical levels at both upstream locations and in the wastewater vary independently of each other. At the upstream locations, the pesticide levels increased with the proportion of arable land in the watershed, whilst decreasing with greater cover of pasture and forest. Interestingly, the same patterns hold true for the composition of wastewater when considering land use in the catchments of the WWTPs. This suggests that pesticide-intensive agricultural crops not only impact surface water quality via diffuse pollution but also increase levels of pesticides in wastewater discharged

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

    PubMed

    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.

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

    PubMed

    Roth, Timothy C; Lima, Steven L

    2007-05-01

    Studies focused on how prey trade-off predation and starvation risk are prevalent in behavioral ecology. However, our current understanding of these trade-offs is limited in one key respect: we know little about the behavior of predators. In this study, we provide some of the first detailed information on temporal patterns in the daily hunting behavior of bird-eating Accipiter hawks and relate that to their prey. During the winters of 1999-2004, twenty-one sharp-shinned hawks (A. striatus) and ten Cooper's hawks (A. cooperii) were intensively radio tracked in rural and urban habitats in western Indiana, USA. Cooper's hawks left roost before sunrise and usually returned to roost around sunset, while sharp-shinned hawks left roost at sunrise or later and returned to roost well before sunset. An overall measure of Cooper's-hawk-induced risk (a composite variable of attack rate and activity patterns) generally reflected the timing of prey activity, with peaks occurring around sunrise and sunset. In contrast, risk induced by the smaller sharp-shinned hawk did not strongly reflect the activity of their prey. Specifically, an early morning peak in prey activity did not correspond to a period with intense hawk activity. The lack of early morning hunting by sharp-shinned hawks may reflect the high risk of owl-induced predation experienced by these hawks. The net effect of this intraguild predation may be to "free" small birds from much hawk-induced predation risk prior to sunrise. This realization presents an alternative to energetics as an explanation for the early morning peak in small bird activity during the winter.

  10. Inferring the Spatio-temporal Patterns of Dengue Transmission from Surveillance Data in Guangzhou, China

    PubMed Central

    Liu, Jiming; Tan, Qi; Shi, Benyun

    2016-01-01

    Background Dengue is a serious vector-borne disease, and incidence rates have significantly increased during the past few years, particularly in 2014 in Guangzhou. The current situation is more complicated, due to various factors such as climate warming, urbanization, population increase, and human mobility. The purpose of this study is to detect dengue transmission patterns and identify the disease dispersion dynamics in Guangzhou, China. Methodology We conducted surveys in 12 districts of Guangzhou, and collected daily data of Breteau index (BI) and reported cases between September and November 2014 from the public health authority reports. Based on the available data and the Ross-Macdonald theory, we propose a dengue transmission model that systematically integrates entomologic, demographic, and environmental information. In this model, we use (1) BI data and geographic variables to evaluate the spatial heterogeneities of Aedes mosquitoes, (2) a radiation model to simulate the daily mobility of humans, and (3) a Markov chain Monte Carlo (MCMC) method to estimate the model parameters. Results/Conclusions By implementing our proposed model, we can (1) estimate the incidence rates of dengue, and trace the infection time and locations, (2) assess risk factors and evaluate the infection threat in a city, and (3) evaluate the primary diffusion process in different districts. From the results, we can see that dengue infections exhibited a spatial and temporal variation during 2014 in Guangzhou. We find that urbanization, vector activities, and human behavior play significant roles in shaping the dengue outbreak and the patterns of its spread. This study offers useful information on dengue dynamics, which can help policy makers improve control and prevention measures. PMID:27105350

  11. Automated swimming activity monitor for examining temporal patterns of toxicant effects on individual Daphnia magna.

    PubMed

    Bahrndorff, Simon; Michaelsen, Thomas Yssing; Jensen, Anne; Marcussen, Laurits Faarup; Nielsen, Majken Elley; Roslev, Peter

    2016-07-01

    Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high-throughput methods for detecting sublethal effects. We have evaluated an automated infra-red (IR) light-based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K2 Cr2 O7 at 15, 20 and 25 °C and 2,4-dichlorophenol at 20 °C. Significant effects (P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K2 Cr2 O7 whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12-18 h. A similar biphasic pattern was observed after 2,4-dichlorophenol exposure at 20 °C. EC50 values for 2,4-dichlorophenol and K2 Cr2 O7 determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC50 of 0.03-0.07 mg l(-1) h(-1) . EC50 values determined after 48 h were comparable or lower than EC50 values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high-throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Capturing spatial and temporal patterns of widespread, extreme flooding across Europe

    NASA Astrophysics Data System (ADS)

    Busby, Kathryn; Raven, Emma; Liu, Ye

    2013-04-01

    Statistical characterisation of physical hazards is an integral part of probabilistic catastrophe models used by the reinsurance industry to estimate losses from large scale events. Extreme flood events are not restricted by country boundaries which poses an issue for reinsurance companies as their exposures often extend beyond them. We discuss challenges and solutions that allow us to appropriately capture the spatial and temporal dependence of extreme hydrological events on a continental-scale, which in turn enables us to generate an industry-standard stochastic event set for estimating financial losses for widespread flooding. By presenting our event set methodology, we focus on explaining how extreme value theory (EVT) and dependence modelling are used to account for short, inconsistent hydrological data from different countries, and how to make appropriate statistical decisions that best characterise the nature of flooding across Europe. The consistency of input data is of vital importance when identifying historical flood patterns. Collating data from numerous sources inherently causes inconsistencies and we demonstrate our robust approach to assessing the data and refining it to compile a single consistent dataset. This dataset is then extrapolated using a parameterised EVT distribution to estimate extremes. Our method then captures the dependence of flood events across countries using an advanced multivariate extreme value model. Throughout, important statistical decisions are explored including: (1) distribution choice; (2) the threshold to apply for extracting extreme data points; (3) a regional analysis; (4) the definition of a flood event, which is often linked with reinsurance industry's hour's clause; and (5) handling of missing values. Finally, having modelled the historical patterns of flooding across Europe, we sample from this model to generate our stochastic event set comprising of thousands of events over thousands of years. We then briefly

  13. Temporal-Spatial Pattern of Carbon Stocks in Forest Ecosystems in Shaanxi, Northwest China.

    PubMed

    Cui, Gaoyang; Chen, Yunming; Cao, Yang

    2015-01-01

    The precise and accurate quantitative evaluation of the temporal and spatial pattern of carbon (C) storage in forest ecosystems is critical for understanding the role of forests in the global terrestrial C cycle and is essential for formulating forest management policies to combat climate change. In this study, we examined the C dynamics of forest ecosystems in Shaanxi, northwest China, based on four forest inventories (1989-1993, 1994-1998, 1999-2003, and 2004-2008) and field-sampling measurements (2012). The results indicate that the total C storage of forest ecosystems in Shaanxi increased by approximately 29.3%, from 611.72 Tg in 1993 to 790.75 Tg in 2008, partially as a result of ecological restoration projects. The spatial pattern of C storage in forest ecosystems mainly exhibited a latitude-zonal distribution across the province, increasing from north (high latitude) to south (low latitude) generally, which signifies the effect of environmental conditions, chiefly water and heat related factors, on forest growth and C sequestration. In addition, different data sources and estimation methods had a significant effect on the results obtained, with the C stocks in 2008 being considerably overestimated (864.55 Tg) and slightly underestimated (778.07 Tg) when measured using the mean C density method and integrated method, respectively. Overall, our results demonstrated that the forest ecosystem in Shaanxi acted as a C sink over the last few decades. However, further studies should be carried out with a focus on adaption of plants to environmental factors along with forest management for vegetation restoration to maximize the C sequestration potential and to better cope with climate change.

  14. 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

    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

  15. Spatial and Temporal Patterns of SMAP Brightness Temperatures for Use in Level 1 TB Characterization

    NASA Astrophysics Data System (ADS)

    Kim, E. J.

    2015-12-01

    1. IntroductionThe recent launch of NASA's Soil Moisture Active Passive (SMAP) mission [Entekhabi, et al] has opened the door to improved brightness temperature (TB) calibration of satellite L-band microwave radiometers, through the use of SMAP's lower noise performance and better immunity to man-made interference (vs. ESA's Soil Moisture Ocean Salinity (SMOS) mission [Kerr, et al]), better spatial resolution (vs. NASA's Aquarius sea surface salinity mission [Le Vine, et al]), and cleaner antenna pattern (vs. SMOS). All three radiometers use/used large homogeneous places on Earth's surface as calibration targets—parts of the ocean, Antarctica, and tropical forests. Despite the recent loss of Aquarius data, there is still hope for creating a longer-term L-band data set that spans the timeframe of all 3 missions. 2. Description of Analyses and Expected Results In this paper, we analyze SMAP brightness temperature data to quantify the spatial and temporal characteristics of external target areas in the oceans, Antarctica, forests, and other areas. Existing analyses have examined these targets in terms of averages, standard deviations, and other basic statistics (for Aquarius & SMOS as well). This paper will approach the problem from a signal processing perspective. Coupled with the use of SMAP's novel RFI-mitigated TBs, and the aforementioned lower noise and cleaner antenna pattern, it is expected that of the 3 L-band missions, SMAP should do the best job of characterizing such external targets. The resulting conclusions should be useful to extract the best possible TB calibration from all 3 missions, helping to inter-compare the TB from the 3 missions, and to eventually inter-calibrate the TBs into a single long-term dataset.

  16. Blood DNA methylation pattern is altered in mesial temporal lobe epilepsy

    PubMed Central

    Long, Hong-Yu; Feng, Li; Kang, Jin; Luo, Zhao-Hui; Xiao, Wen-Biao; Long, Li-Li; Yan, Xiao-Xin; Zhou, Luo; Xiao, Bo

    2017-01-01

    Mesial temporal lobe epilepsy (MTLE) is a common epileptic disorder; little is known whether it is associated with peripheral epigenetic changes. Here we compared blood whole genomic DNA methylation pattern in MTLE patients (n = 30) relative to controls (n = 30) with the Human Methylation 450 K BeadChip assay, and explored genes and pathways that were differentially methylated using bioinformatics profiling. The MTLE and control groups showed significantly different (P < 1.03e-07) DNA methylation at 216 sites, with 164 sites involved hyper- and 52 sites hypo- methylation. Two hyper- and 32 hypo-methylated sites were associated with promoters, while 87 hyper- and 43 hypo-methylated sites corresponded to coding regions. The differentially methylated genes were largely related to pathways predicted to participate in anion binding, oxidoreductant activity, growth regulation, skeletal development and drug metabolism, with the most distinct ones included SLC34A2, CLCN6, CLCA4, CYP3A43, CYP3A4 and CYP2C9. Among the MTLE patients, panels of genes also appeared to be differentially methylated relative to disease duration, resistance to anti-epileptics and MRI alterations of hippocampal sclerosis. The peripheral epigenetic changes observed in MTLE could be involved in certain disease-related modulations and warrant further translational investigations. PMID:28276448

  17. 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.

  18. Patterns of spatial and temporal distribution of the asparagus miner (Diptera: Agromyzidae): implications for management.

    PubMed

    Morrison, William R; Szendrei, Zsofia

    2013-06-01

    The asparagus miner is an obligatory feeder on asparagus and a putative vector for pathogenic fungi implicated in the early decline of asparagus fields. To date, the distribution of the asparagus miner over space and time is poorly understood. Our study evaluated the spatial and temporal pattern of adult asparagus miners in commercial asparagus fields in Michigan in 2011 and 2012. We sampled adults and damage weekly during the growing season using yellow sticky traps outside, at the edge, and inside commercial fields. Yellow sticky traps at each trapping location were placed at the canopy and ground level to determine vertical distribution of adults. During the first generation, adults were more evenly distributed throughout the field. In the second generation, adults were more commonly found on the edge of the field. Overall, there was a greater percent of mining damage near the edge of the field. Additionally, three times as many asparagus miners were found in the canopy compared with ground-level traps. There were 12 times as many asparagus miner adults on edges bordered by another asparagus field than on ones bordered by forest. Taken together, our results indicate that while asparagus miner management in the beginning of the growing season should focus on the entire field, in the latter half of the season, growers could save money and resources by targeting miner adults at the edges of fields. Finally, conserving the remaining naturally forested landscape and planting borders of trees may help ameliorate pest pressure in asparagus fields.

  19. Temporal and spatial patterns of anthropogenic disturbance at McMurdo Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Kennicutt, Mahlon C., II; Klein, Andrew; Montagna, Paul; Sweet, Stephen; Wade, Terry; Palmer, Terence; Sericano, Jose; Denoux, Guy

    2010-07-01

    Human visitations to Antarctica have increased in recent decades, raising concerns about preserving the continent's environmental quality. To understand the spatial and temporal patterns of anthropogenic disturbances at the largest scientific station in Antarctica, McMurdo Station, a long-term monitoring program has been implemented. Results from the first nine years (1999-2007) of monitoring are reported. Most physical disturbance of land surfaces occurred prior to 1970 during initial establishment of the station. Hydrocarbons from fuel and anthropogenic metals occur in patches of tens to hundreds of square meters in areas of fuel usage and storage. Most soil contaminant concentrations are not expected to elicit biological responses. Past disposal practices have contaminated marine sediments with polychlorinated biphenyls (PCBs), petroleum hydrocarbons, and metals in close proximity to the station that often exceed concentrations expected to elicit biological responses. Chemical contamination and organic enrichment reduced marine benthic ecological integrity within a few hundred meters offshore of the station. Contaminants were detected in marine benthic organisms confirming bioavailability and uptake. PCBs in sediments are similar to suspected source materials, indicating minimal microbial degradation decades after release. Anthropogenic disturbance of the marine environment is likely to persist for decades. A number of monitoring design elements, indicators and methodologies used in temperate climates were effective and provide guidance for monitoring programs elsewhere in Antarctica.

  20. Spatial and temporal patterns of debris flow deposition in the Oregon Coast Range, USA

    USGS Publications Warehouse

    May, Christine L.; Gresswell, Robert E.

    2004-01-01

    Patterns of debris-flow occurrence were investigated in 125 headwater basins in the Oregon Coast Range. Time since the previous debris-flows was established using dendrochronology, and recurrence interval estimates ranged from 98 to 357 years. Tributary basins with larger drainage areas had a greater abundance of potential landslide source areas and a greater frequency of scouring events compared to smaller basins. The flux rate of material delivered to the confluence with a larger river influenced the development of small-scale debris-flow fans. Fans at the mouths of tributary basins with smaller drainage areas had a higher likelihood of being eroded by the mainstem river in the interval between debris-flows, compared to bigger basins that had larger, more persistent fans. Valley floor width of the receiving channel also influenced fan development because it limited the space available to accommodate fan formation. Of 63 recent debris-flows, 52% delivered sediment and wood directly to the mainstem river, 30% were deposited on an existing fan before reaching the mainstem, and 18% were deposited within the confines of the tributary valley before reaching the confluence. Spatial variation in the location of past and present depositional surfaces indicated that sequential debris-flow deposits did not consistently form in the same place. Instead of being spatially deterministic, results of this study suggest that temporally variable and stochastic factors may be important for predicting the runout length of debris-flows.

  1. We'll meet again: revealing distributional and temporal patterns of social contact.

    PubMed

    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).

  2. Structural and functional correlates of behavioral pattern separation in the hippocampus and medial temporal lobe.

    PubMed

    Doxey, Christopher R; Kirwan, C Brock

    2015-04-01

    Structures of the medial temporal lobe (MTL) are known to be involved in declarative memory processes. However, little is known about how age-related changes in MTL structures, white matter integrity, and functional connectivity affect pattern separation processes in the MTL. In this study, we used magnetic resonance imaging (MRI) to measure the volumes of MTL regions of interest, including hippocampal subfields (dentate gyrus, CA3, CA1, and subiculum) in healthy older and younger adults. Additionally, we used diffusion tensor imaging to measure white matter integrity for both groups. Finally, we used functional MRI to acquire resting functional connectivity measures for both groups. We show that, along with age, the volume of left CA3/dentate gyrus predicts memory performance. Differences in fractional anisotropy and the strength of resting functional connections between the hippocampus and other cortical structures implicated in memory processing were not significant predictors of performance. As previous studies have only hinted, it seems that the size of left CA3/dentate gyrus contributes more to successful discrimination between similar mnemonic representations than other hippocampal sub-fields, MTL structures, and other neuroimaging correlates. Accordingly, the implications of aging and atrophy on lure discrimination capacities are discussed.

  3. Characterization of spatial-temporal patterns in dynamic speckle sequences using principal component analysis

    NASA Astrophysics Data System (ADS)

    López-Alonso, José Manuel; Grumel, Eduardo; Cap, Nelly Lucía; Trivi, Marcelo; Rabal, Héctor; Alda, Javier

    2016-12-01

    Speckle is being used as a characterization tool for the analysis of the dynamics of slow-varying phenomena occurring in biological and industrial samples at the surface or near-surface regions. The retrieved data take the form of a sequence of speckle images. These images contain information about the inner dynamics of the biological or physical process taking place in the sample. Principal component analysis (PCA) is able to split the original data set into a collection of classes. These classes are related to processes showing different dynamics. In addition, statistical descriptors of speckle images are used to retrieve information on the characteristics of the sample. These statistical descriptors can be calculated in almost real time and provide a fast monitoring of the sample. On the other hand, PCA requires a longer computation time, but the results contain more information related to spatial-temporal patterns associated to the process under analysis. This contribution merges both descriptions and uses PCA as a preprocessing tool to obtain a collection of filtered images, where statistical descriptors are evaluated on each of them. The method applies to slow-varying biological and industrial processes.

  4. 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.

  5. Temporal Patterns in Bivalve Excurrent Flow Under Varying Ambient Flow Conditions

    NASA Astrophysics Data System (ADS)

    Delavan, S. K.; Webster, D. R.

    2008-11-01

    The predator-prey relationship between blue crabs (Callinectes sapidus) and bivalve clams (Mercenaria mercenaria) is mediated by the transport of metabolites released by the prey (clams) and transported downstream as a passive scalar. This study focuses on how the prey behavior contributes to the information available within the odorant plume. Clams may modify factors such as excurrent flux, flow unsteadiness, and siphon height and diameter. A Particle Image Velocimetry (PIV) system has been used to quantify the temporal patterns in the excurrent jet of the bivalve siphon under varying ambient flow conditions. According to a spectral analysis of siphon excurrent velocity time records, there is a low frequency periodic component that could contribute to the mixing of clam metabolites through the generation of persistent jet vorticies. Also, fractal analysis of the velocity time records shows that as the ambient velocity increases the excurrent velocity becomes more correlated and less random. These results suggest that for high ambient flow a low frequency periodicity may be sufficient to promote the mixing and dilution of metabolites. In contrast, for low ambient flow more random siphon excurrent velocity may be required to reduce the amount of information available to predators in the downstream odorant plume.

  6. Multi-Voxel Pattern Analysis of Noun and Verb Differences in Ventral Temporal Cortex Marked Revision

    PubMed Central

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

    2014-01-01

    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

  7. Temporal Patterns of Larval Fish Occurrence in a Large Subtropical River

    PubMed Central

    Shuai, Fangmin; Li, Xinhui; Li, Yuefei; Li, Jie; Yang, Jiping; Lek, Sovan

    2016-01-01

    Knowledge of temporal patterns of larval fish occurrence is limited in south China, despite its ecological importance. This research examines the annual and seasonal patterns of fish larval presence in the large subtropical Pearl River. Data is based on samples collected every two days, from 2006 to 2013. In total, 45 taxa representing 13 families and eight orders were sampled. The dominant larval family was Cyprinidae, accounting for 27 taxa. Squaliobarbus curriculus was the most abundant species, followed by Megalobrama terminalis, Xenocypris davidi, Cirrhinus molitorella, Hemiculter leuscisculus and Squalidus argentatus. Fish larvae abundances varied significantly throughout the seasons (multivariate analyses: Cluster, SIMPROF and ANOSIM). The greatest numbers occurred between May and September, peaking from June through August, which corresponds to the reproductive season. In this study, redundancy analysis was used to describe the relationship between fish larval abundance and associated environmental factors. Mean water temperature, river discharge, atmospheric pressure, maximum temperature and precipitation play important roles in larval occurrence patterns. According to seasonal variations, fish larvae occurrence is mainly affected by water temperature. It was also noted that the occurrence of Salanx reevesii and Cyprinus carpio larvae is associated with higher dissolved oxygen (DO) concentrations, higher atmospheric pressure and lower water temperatures which occur in the spring. On the other hand, M. terminalis, X. davidi, and C. molitorella are associated with high precipitation, high river discharge, low atmospheric pressure and low DO concentrations which featured during the summer months. S. curriculus also peaks in the summer and is associated with peak water temperatures and minimum NH3–N concentrations. Rhinogobius giurinus occur when higher atmospheric pressure, lower precipitation and lower river discharges occur in the autumn. Dominant fish

  8. Rich do not rise early: spatio-temporal patterns in the mobility networks of different socio-economic classes

    NASA Astrophysics Data System (ADS)

    Lotero, Laura; Hurtado, Rafael G.; Floría, Luis Mario; Gómez-Gardeñes, Jesús

    2016-10-01

    We analyse the urban mobility in the cities of Medellín and Manizales (Colombia). Each city is represented by six mobility networks, each one encoding the origin-destination trips performed by a subset of the population corresponding to a particular socio-economic status. The nodes of each network are the different urban locations whereas links account for the existence of a trip between two different areas of the city. We study the main structural properties of these mobility networks by focusing on their spatio-temporal patterns. Our goal is to relate these patterns with the partition into six socio-economic compartments of these two societies. Our results show that spatial and temporal patterns vary across these socio-economic groups. In particular, the two datasets show that as wealth increases the early-morning activity is delayed, the midday peak becomes smoother and the spatial distribution of trips becomes more localized.

  9. Rich do not rise early: spatio-temporal patterns in the mobility networks of different socio-economic classes.

    PubMed

    Lotero, Laura; Hurtado, Rafael G; Floría, Luis Mario; Gómez-Gardeñes, Jesús

    2016-10-01

    We analyse the urban mobility in the cities of Medellín and Manizales (Colombia). Each city is represented by six mobility networks, each one encoding the origin-destination trips performed by a subset of the population corresponding to a particular socio-economic status. The nodes of each network are the different urban locations whereas links account for the existence of a trip between two different areas of the city. We study the main structural properties of these mobility networks by focusing on their spatio-temporal patterns. Our goal is to relate these patterns with the partition into six socio-economic compartments of these two societies. Our results show that spatial and temporal patterns vary across these socio-economic groups. In particular, the two datasets show that as wealth increases the early-morning activity is delayed, the midday peak becomes smoother and the spatial distribution of trips becomes more localized.

  10. Rich do not rise early: spatio-temporal patterns in the mobility networks of different socio-economic classes

    PubMed Central

    Hurtado, Rafael G.; Floría, Luis Mario

    2016-01-01

    We analyse the urban mobility in the cities of Medellín and Manizales (Colombia). Each city is represented by six mobility networks, each one encoding the origin-destination trips performed by a subset of the population corresponding to a particular socio-economic status. The nodes of each network are the different urban locations whereas links account for the existence of a trip between two different areas of the city. We study the main structural properties of these mobility networks by focusing on their spatio-temporal patterns. Our goal is to relate these patterns with the partition into six socio-economic compartments of these two societies. Our results show that spatial and temporal patterns vary across these socio-economic groups. In particular, the two datasets show that as wealth increases the early-morning activity is delayed, the midday peak becomes smoother and the spatial distribution of trips becomes more localized. PMID:27853531

  11. Spatial-temporal patterns in Mediterranean carnivore road casualties: Consequences for mitigation

    USGS Publications Warehouse

    Grilo, C.; Bissonette, J.A.; Santos-Reis, M.

    2009-01-01

    Many carnivores have been seriously impacted by the expansion of transportation systems and networks; however we know little about carnivore response to the extent and magnitude of road mortality, or which age classes may be disproportionately impacted. Recent research has demonstrated that wildlife-vehicle-collisions (WVC) involving carnivores are modulated by temporal and spatial factors. Thus, we investigated road mortality on a guild of small and medium-sized carnivores in southern Portugal using road-kill data obtained from a systematic 36 months monitoring period along highways (260 km) and national roads (314 km) by addressing the following questions: (a) which species and age class are most vulnerable to WVC? (b) are there temporal and/or spatial patterns in road-kill? and (c) which life-history and/or spatial factors influence the likelihood of collisions? We recorded a total of 806 carnivore casualties, which represented an average of 47 ind./100 km/year. Red fox and stone marten had the highest mortality rates. Our findings highlight three key messages: (1) the majority of road-killed individuals were adults of common species; (2) all carnivores, except genets, were more vulnerable during specific life-history phenological periods: higher casualties were observed when red fox and stone marten were provisioning young, Eurasian badger casualties occurred more frequently during dispersal, and higher Egyptian mongoose mortality occurred during the breeding period; and (3) modeling demonstrated that favorable habitat, curves in the road, and low human disturbance were major contributors to the deadliest road segments. Red fox carcasses were more likely to be found on road sections with passages distant from urban areas. Conversely, stone marten mortalities were found more often on national roads with high of cork oak woodland cover; Egyptian mongoose and genet road-kills were found more often on road segments close to curves. Based on our results, two key

  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

  13. 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.

  14. 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

  15. Spatio-Temporal Pattern and Socio-Economic Factors of Bacillary Dysentery at County Level in Sichuan Province, China.

    PubMed

    Ma, Yue; Zhang, Tao; Liu, Lei; Lv, Qiang; Yin, Fei

    2015-10-15

    Bacillary dysentery (BD) remains a big public health problem in China. Effective spatio-temporal monitoring of BD incidence is important for successful implementation of control and prevention measures. This study aimed to examine the spatio-temporal pattern of BD and analyze socio-economic factors that may affect BD incidence in Sichuan province, China. Firstly, we used space-time scan statistic to detect the high risk spatio-temporal clusters in each year. Then, bivariate spatial correlation and Bayesian spatio-temporal model were utilized to examine the associations between the socio-economic factors and BD incidence. Spatio-temporal clusters of BD were mainly located in the northern-southern belt of the midwest area of Sichuan province. The proportion of primary industry, the proportion of rural population and the rates of BD incidence show statistically significant positive correlation. The proportion of secondary industry, proportion of tertiary Industry, number of beds in hospitals per thousand persons, medical and technical personnel per thousand persons, per capital GDP and the rate of BD incidence show statistically significant negative correlation. The best fitting spatio-temporal model showed that medical and technical personnel per thousand persons and per capital GDP were significantly negative related to the risk of BD.

  16. The use of satellite data for monitoring temporal and spatial patterns of fire: a comprehensive review

    NASA Astrophysics Data System (ADS)

    Lasaponara, R.

    2009-04-01

    Remotely sensed (RS) data can fruitfully support both research activities and operative monitoring of fire at different temporal and spatial scales with a synoptic view and cost effective technologies. "The contribution of remote sensing (RS) to forest fires may be grouped in three categories, according to the three phases of fire management: (i) risk estimation (before fire), (ii) detection (during fire) and (iii) assessment (after fire)" Chuvieco (2006). Relating each phase, wide research activities have been conducted over the years. (i) Risk estimation (before fire) has been mainly based on the use of RS data for (i) monitoring vegetation stress and assessing variations in vegetation moisture content, (ii) fuel type mapping, at different temporal and spatial scales from global, regional down to a local scale (using AVHRR, MODIS, TM, ASTER, Quickbird images and airborne hyperspectral and LIDAR data). Danger estimation has been mainly based on the use of AVHRR (onborad NOAA), MODIS (onboard TERRA and AQUA), VEGETATION (onboard SPOT) due to the technical characteristics (i.e. spectral, spatial and temporal resolution). Nevertheless microwave data have been also used for vegetation monitoring. (ii) Detection: identification of active fires, estimation of fire radiative energy and fire emission. AVHRR was one of the first satellite sensors used for setting up fire detection algorithms. The availbility of MODIS allowed us to obtain global fire products free downloaded from NASA web site. Sensors onboard geostationary satellite platforms, such as GOES, SEVIRI, have been used for fire detection, to obtain a high temporal resolution (at around 15 minutes) monitoring of active fires. (iii) Post fire damage assessment includes: burnt area mapping, fire emission, fire severity, vegetation recovery, fire resilience estimation, and, more recently, fire regime characterization. Chuvieco E. L. Giglio, C. Justice, 2008 Global charactrerization of fire activity: toward defining

  17. MP-1 biofeedback: luminous pattern stimulus versus acoustic biofeedback in age related macular degeneration (AMD).

    PubMed

    Vingolo, Enzo M; Salvatore, Serena; Limoli, Paolo G

    2013-03-01

    In this study we evaluated the efficacy of visual rehabilitation by means of two different types of biofeedback techniques in patients with age related macular degeneration (AMD). Thirty patients, bilaterally affected by AMD, were randomly divided in two groups: one group was treated with an acoustic biofeedback (AB group), the other was treated with luminous biofeedback of a black and white checkerboard flickering during the examination (LB group). All patients underwent a complete ophthalmological examination. Rehabilitation consisted of 12 training sessions of 10 min for each eye performed once a week for both groups. Both groups showed better visual performance after rehabilitation and luminous flickering biofeedback stimulus showed a statistically significant improvement in training the patients to modify their preferred retinal locus in comparison to acoustic biofeedback. This suggests that it might be possible in the damaged retina to override dead photoreceptor and outer retinal layers and involve residual surviving cells, as well as amplify and integrate retinal and brain cortex plasticity by using other spared channels towards associative pathways.

  18. The acoustic salience of prosody trumps infants' acquired knowledge of language-specific prosodic patterns

    PubMed Central

    Hawthorne, Kara; Mazuka, Reiko; Gerken, LouAnn

    2015-01-01

    There is mounting evidence that prosody facilitates grouping the speech stream into syntactically-relevant units (e.g., Hawthorne & Gerken, 2014; Soderstrom, Kemler Nelson, & Jusczyk, 2005). We ask whether prosody's role in syntax acquisition relates to its general acoustic salience or to the learner's acquired knowledge of correlations between prosody and syntax in her native language. English- and Japanese-acquiring 19-month-olds listened to sentences from an artificial grammar with non-native prosody (Japanese or English, respectively), then were tested on their ability to recognize prosodically-marked constituents when the constituents had moved to a new position in the sentence. Both groups were able to use non-native prosody to parse speech into cohesive, reorderable, syntactic constituent-like units. Comparison with Hawthorne & Gerken (2014), in which English-acquiring infants were tested on sentences with English prosody, suggests that 19-month-olds are equally adept at using native and non-native prosody for at least some types of learning tasks and, therefore, that prosody is useful in early syntactic segmentation because of its acoustic salience. PMID:25870497

  19. Analysis and Monitoring of the Spatio-temporal Aerosol Patterns over Bangladesh

    NASA Astrophysics Data System (ADS)

    Mamun, M.; Islam, M.

    2012-12-01

    Nowadays climate change is the burning issue and atmospheric aerosols are vital parameter of the global climate system. So, atmospheric aerosols are one of the hot topics for present scientific research. Most remote sensing methods retrieve aerosol optical depth (AOD) to assess the aerosols and their various effects on environmental and climate system. However, there is lack of studies dealing with monitoring of aerosol patterns over Bangladesh. In this research, we have analyzed the spatial and temporal variations in aerosol load over Bangladesh, using MODerate resolution Imaging Spectroradiometer (MODIS) Level 3 remote sensing data. A Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to generate a backward trajectory in order to identify the origins of air masses, with the aim of understanding these spatial and temporal variabilities in aerosol concentrations. During the last decade, AODs have increased across Bangladesh and revealed a higher AOD concentration in western part but a much cleaner environment in eastern part. An assessment of monthly mean variations in AOD has exhibited maximum AODs in June and minimum AODs in October. Looking over seasonal variations during the last decade over Bangladesh showed maximum AOD values during the summer, while minimum AOD values showed during the post monsoon also an evidence of a decreasing AOD trend showed during the monsoon can be owing to an increase in monsoonal rainfall in Bangladesh, while all other seasons showed increasing trends. Northwestern part of Bangladesh has showed at the top of AOD concentration in winter season during the year 2010. Dense fog activities in northern part of Bangladesh may be the causes of this high AOD distribution. We also documented, the regional AOD variations over seven different divisions of Bangladesh, for which Dhaka and Sylhet divisions showed decreasing trends where all others showed increasing trends. Annual mean AODs have highest levels in

  20. [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.

  1. Temporal Patterns of Medications Dispensed to Children and Adolescents in a National Insured Population

    PubMed Central

    Olson, Karen L.; Mandl, Kenneth D.

    2012-01-01

    This study aimed to comprehensively describe prevalence and temporal dispensing patterns for medications prescribed to children and adolescents in the United States. Participants were 1.6 million children (49% female) under 18 years old enrolled in a nation-wide, employer-provided insurance plan. All medication claims from 1999–2006 were reviewed retrospectively. Drugs were assigned to 16 broad therapeutic categories. Effects of trend over time, seasonality, age and gender on overall and within category prevalence were examined. Results: Mean monthly prevalence for dispensed medications was 23.5% (range 19.4–27.5), with highest rates in winter and lowest in July. The age group with the highest prevalence was one-year-old children. On average each month, 17.1% of all children were dispensed a single drug and 6.4% were dispensed two or more. Over time, prevalence for two or more drugs did not change, but the proportion of children dispensed a single drug decreased (slope -.02%, p = .001). Overall, boys had higher monthly rates than girls (average difference 0.9%, p = .002). However, differences by gender were greatest during middle childhood, especially for respiratory and central nervous system agents. Contraceptives accounted for a large proportion of dispensed medication to older teenage girls. Rates for the drugs with the highest prevalence in this study were moderately correlated (average Pearson r.66) with those from a previously published national survey. Conclusion: On average, nearly one quarter of a population of insured children in the United States was dispensed medication each month. This rate decreased somewhat over time, primarily because proportionally fewer children were dispensed a single medication. The rate for two or more drugs dispensed simultaneously remained steady. PMID:22829905

  2. 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.

  3. Spatial and temporal patterns of dissolved organic matter optical properties across large rivers in Africa

    NASA Astrophysics Data System (ADS)

    Lambert, Thibault; Darchambeau, François; Vieira Borges, Alberto; Alhou, Bassirou; Mbega, Jean-Daniel; Teodoru, Cristian; Marwick, Trent Richard; Bouillon, Steven

    2014-05-01

    Tropical rivers have disproportionally high carbon transport and outgassing compared to temperate and Arctic rivers. Yet the cycling of dissolved organic matter (DOM) within these systems is still poorly studied with the exception of the Amazon basin. The chromophoric or colored dissolved organic matter (CDOM) is the fraction of DOM that absorbs ultraviolet and visible light. As the biochemical nature of DOM (and CDOM) defines its optical properties, optical measurements are particularly useful to assess the composition of DOM in freshwater and hence can be applied as proxies for assessments of DOM sources and its biogeochemical role. However, less is known on how specific optical characteristics can be applied as proxies and how these proxies vary from one system to another. In this study we compared concentrations and stable isotopic signature of dissolved organic carbon with optical properties of DOM from diverse tropical river systems across the African continent including the Congo basin, the Zambezi basin, the Ogooué basin and the Niger basin. These major rivers of the African continent were monitored for long period (from 1-3 years) at biweekly frequency. This large dataset allowed us to compare the spatial and temporal patterns of DOM quality along various environmental gradients, including hydrology, river size, terrestrial vegetation and connectivity to terrestrial inputs. The optical proxies presented and discussed in this study include absorption coefficients a(Λ) at different wavelength (254, 300, 350 and 440 nm), spectral slopes (S275-295and S350-400), the spectral slope ratio (SR=S275-295:S350-400) and the a(250):a(365) ratio.

  4. Does Weather Matter? The Effect of Weather Patterns and Temporal Factors on Pediatric Orthopedic Trauma Volume

    PubMed Central

    Livingston, Kristin S.; Miller, Patricia E.; Lierhaus, Anneliese; Matheney, Travis H.; Mahan, Susan T.

    2016-01-01

    Objectives: Orthopaedists often speculate how weather and school schedule may influence pediatric orthopedic trauma volume, but few studies have examined this. This study aims to determine: how do weather patterns, day, month, season and public school schedule influence the daily frequency of pediatric orthopedic trauma consults and admissions? Methods: With IRB approval, orthopedic trauma data from a level 1 pediatric trauma center, including number of daily orthopedic trauma consults and admissions, were collected from July 2009 to March 2012. Historical weather data (high temperatures, precipitation and hours of daylight), along with local public school schedule data were collected for the same time period. Univariate and multivariate regression models were used to show the average number of orthopedic trauma consults and admissions as a function of weather and temporal variables. Results: High temperature, precipitation, month and day of the week significantly affected the number of daily consults and admissions. The number of consults and admissions increased by 1% for each degree increase in temperature (p=0.001 and p<0.001, respectively), and decreased by 21% for each inch of precipitation (p<0.001, p=0.006). Daily consults on snowy days decreased by an additional 16% compared to days with no precipitation. November had the lowest daily consult and admission rate, while September had the highest. Daily consult rate was lowest on Wednesdays and highest on Saturdays. Holiday schedule was not independently significant. Conclusion: Pediatric orthopedic trauma consultations and admissions are highly linked to temperature and precipitation, as well as day of the week and time of year. PMID:27990193

  5. Systematic temporal patterns in the relationship between housing development and forest bird biodiversity.

    PubMed

    Pidgeon, Anna M; Flather, Curtis H; Radeloff, Volker C; Lepczyk, Christopher A; Keuler, Nicholas S; Wood, Eric M; Stewart, Susan I; Hammer, Roger B

    2014-10-01

    As people encroach increasingly on natural areas, one question is how this affects avian biodiversity. The answer to this is partly scale-dependent. At broad scales, human populations and biodiversity concentrate in the same areas and are positively associated, but at local scales people and biodiversity are negatively associated with biodiversity. We investigated whether there is also a systematic temporal trend in the relationship between bird biodiversity and housing development. We used linear regression to examine associations between forest bird species richness and housing growth in the conterminous United States over 30 years. Our data sources were the North American Breeding Bird Survey and the 2000 decennial U.S. Census. In the 9 largest forested ecoregions, housing density increased continually over time. Across the conterminous United States, the association between bird species richness and housing density was positive for virtually all guilds except ground nesting birds. We found a systematic trajectory of declining bird species richness as housing increased through time. In more recently developed ecoregions, where housing density was still low, the association with bird species richness was neutral or positive. In ecoregions that were developed earlier and where housing density was highest, the association of housing density with bird species richness for most guilds was negative and grew stronger with advancing decades. We propose that in general the relationship between human settlement and biodiversity over time unfolds as a 2-phase process. The first phase is apparently innocuous; associations are positive due to coincidence of low-density housing with high biodiversity. The second phase is highly detrimental to biodiversity, and increases in housing density are associated with biodiversity losses. The long-term effect on biodiversity depends on the final housing density. This general pattern can help unify our understanding of the relationship

  6. Spatial and Temporal Patterns of Global NDVI Trends: Correlations with Climate and Human Factors

    NASA Astrophysics Data System (ADS)

    LIU, Y.; Li, S.

    2015-12-01

    Abstract: Changes in vegetation activity are driven by multiple natural and anthropogenic factors, which can be reflected by Normalized Difference Vegetation Index (NDVI) derived from satellite. In this paper, NDVI trends from 1982 to 2012 are first estimated by the Theil-Sen median slope method to explore their spatial and temporal patterns. Then the impact of climate variables and human activity on the observed NDVI trends is analyzed. Our results show on average NDVI increased by 0.46×10-3 per year from 1982 to 2012 globally with decadal variations. For most regions of the world, a greening (increasing) - browning(decreasing) - greening (G-B-G) trend is observed over the periods 1982-2004, 1995-2004, and 2005-2012, respectively. A positive partial correlation of NDVI and temperature is observed in the first period but it decreases and occasionally becomes negative in the following periods, especially in the Humid Temperate and Dry Domain Regions. This suggests a weakened effect of temperature on vegetation growth. Precipitation, on the other hand, is found to have a positive impact on the NDVI trend. This effect becomes stronger in the third period of 1995-2004, especially in the Dry Domain Region. Anthropogenic effects and human activities, derived here from the Human Footprint Dataset and the associated Human Influence Index (HII), have varied impacts on the magnitude (absolute value) of the NDVI trends across continents. Significant positive effects are found in Asia, Africa, and Europe, suggesting that intensive human activity could accelerate the change in NDVI and vegetation. A more accurate attribution of vegetation change to specific climatic and anthropogenic factors is instrumental to understand vegetation dynamics and requires further research.

  7. Temporal Pattern of the Repeated Bout Effect of Eccentric Exercise on Delayed-Onset Muscle Soreness

    PubMed Central

    Cleary, Michelle A.; Kimura, Iris F.; Sitler, Michael R.; Kendrick, Zebulon V.

    2002-01-01

    Objective: To determine the temporal pattern of the repeated bout effect of eccentric exercise on perceived pain and muscular tenderness associated with delayed-onset muscle soreness (DOMS). Design and Setting: Subjects completed 2 identical eccentric exercise bouts separated by 6, 7, 8, or 9 weeks. The experiment was conducted in a biokinetics research laboratory. Subjects: Sixteen male and 15 female untrained subjects (age = 24.59 ± 4.42 years, height = 171.71 ± 7.81 cm, weight = 73.00 ± 11.20 kg). Measurements: Two physiologic characteristics of DOMS were measured immediately before and 0, 24, 48, and 72 hours after each eccentric exercise bout. Perceived pain was measured using a visual analog scale (VAS), and muscular tenderness was measured using a punctate tenderness gauge (PTG). Results: Two 4 × 2 × 5 (group × bout × time) analyses of variance with repeated measures on the bout and time factors were performed on the VAS and PTG data. Significant (P < .05) main effects were found for group, bout, and time for the VAS and the PTG data. No significant interactions were detected. Post hoc analysis revealed significantly less perceived pain for the 9-week group than the 8-week group. The 7-week group had significantly less and the 8-week group had significantly more muscular tenderness than any other group. Perceived pain and muscular tenderness were significantly less after exercise bout 2 than after exercise bout 1. All subjects had significantly less perceived pain and muscular tenderness pre-exercise than 0 and 24 hours after the eccentric exercise bouts. Conclusions: An effective prophylaxis for perceived pain and muscular tenderness associated with DOMS is the performance of an eccentric exercise bout 6 to 9 weeks before a similar exercise bout. PMID:12937441

  8. Temporal patterns in the foraging behavior of sea otters in Alaska

    USGS Publications Warehouse

    Esslinger, George G.; Bodkin, James L.; Breton, André R.; Burns, Jennifer M.; Monson, Daniel H.

    2014-01-01

    Activity time budgets in apex predators have been proposed as indicators of population status relative to resource limitation or carrying capacity. We used archival time-depth recorders implanted in 15 adult female and 4 male sea otters (Enhydra lutris) from the northernmost population of the species, Prince William Sound, Alaska, USA, to examine temporal patterns in their foraging behavior. Sea otters that we sampled spent less time foraging during summer (females 8.8 hr/day, males 7.9 hr/day) than other seasons (females 10.1–10.5 hr/day, males 9.2–9.5 hr/day). Both sexes showed strong preferences for diurnal foraging and adjusted their foraging effort in response to the amount of available daylight. One exception to this diurnal foraging mode occurred after females gave birth. For approximately 3 weeks post-partum, females switched to nocturnal foraging, possibly in an effort to reduce the risk of predation by eagles on newborn pups. We used multilevel mixed regression models to assess the contribution of several biological and environmental covariates to variation in the daily foraging effort of parous females. In the random effects only model, 87% of the total variation in foraging effort was within-otter variation. The relatively small among-otter variance component (13%) indicates substantial consistency in the foraging effort of sea otters in this northern population. In the top 3 models, 17% of the within-otter variation was explained by reproductive stage, day length, wind speed, air temperature and a wind speed × air temperature interaction. This study demonstrates the potential importance of environmental and reproductive effects when using activity budgets to assess population status relative to carrying capacity.

  9. Long-period seismic events with strikingly regular temporal patterns on Katla volcano's south flank (Iceland)

    NASA Astrophysics Data System (ADS)

    Sgattoni, Giulia; Jeddi, Zeinab; Gudmundsson, Ólafur; Einarsson, Páll; Tryggvason, Ari; Lund, Björn; Lucchi, Federico

    2016-09-01

    Katla is a threatening volcano in Iceland, partly covered by the Mýrdalsjökull ice cap. The volcano has a large caldera with several active geothermal areas. A peculiar cluster of long-period seismic events started on Katla's south flank in July 2011, during an unrest episode in the caldera that culminated in a glacier outburst. The seismic events were tightly clustered at shallow depth in the Gvendarfell area, 4 km south of the caldera, under a small glacier stream at the southern margin of Mýrdalsjökull. No seismic events were known to have occurred in this area before. The most striking feature of this seismic cluster is its temporal pattern, characterized by regular intervals between repeating seismic events, modulated by a seasonal variation. Remarkable is also the stability of both the time and waveform features over a long time period, around 3.5 years. We have not found any comparable examples in the literature. Both volcanic and glacial processes can produce similar waveforms and therefore have to be considered as potential seismic sources. Discerning between these two causes is critical for monitoring glacier-clad volcanoes and has been controversial at Katla. For this new seismic cluster on the south flank, we regard volcano-related processes as more likely than glacial ones for the following reasons: 1) the seismic activity started during an unrest episode involving sudden melting of the glacier and a jökulhlaup; 2) the glacier stream is small and stagnant; 3) the seismicity remains regular and stable for years; 4) there is no apparent correlation with short-term weather changes, such as rainstorms. We suggest that a small, shallow hydrothermal system was activated on Katla's south flank in 2011, either by a minor magmatic injection or by changes of permeability in a local crack system.

  10. 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

  11. Spatial-Temporal Patterns of Viral Amplification and Interference Initiated by a Single Infected Cell

    PubMed Central

    Akpinar, Fulya; Inankur, Bahar

    2016-01-01

    ABSTRACT When viruses infect their host cells, they can make defective virus-like particles along with intact virus. Cells coinfected with virus and defective particles often exhibit interference with virus growth caused by the competition for resources by defective genomes. Recent reports of the coexistence and cotransmission of such defective interfering particles (DIPs) in vivo, across epidemiological length and time scales, suggest a role in viral pathogenesis, but it is not known how DIPs impact infection spread, even under controlled culture conditions. Using fluorescence microscopy, we quantified coinfections of vesicular stomatitis virus (VSV) expressing a fluorescent reporter protein and its DIPs on BHK-21 host cell monolayers. We found that viral gene expression was more delayed, infections spread more slowly, and patterns of spread became more “patchy” with higher DIP inputs to the initial cell. To examine how infection spread might depend on the behavior of the initial coinfected cell, we built a computational model, adapting a cellular automaton (CA) approach to incorporate kinetic data on virus growth for the first time. Specifically, changes in observed patterns of infection spread could be directly linked to previous high-throughput single-cell measures of virus-DIP coinfection. The CA model also provided testable hypotheses on the spatial-temporal distribution of the DIPs, which remain governed by their predator-prey interaction. More generally, this work offers a data-driven computational modeling approach for better understanding of how single infected cells impact the multiround spread of virus infections across cell populations. IMPORTANCE Defective interfering particles (DIPs) compete with intact virus, depleting host cell resources that are essential for virus growth and infection spread. However, it is not known how such competition, strong or weak, ultimately affects the way in which infections spread and cause disease. In this study

  12. 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. δ13C data indicate intensified carbon fixation during organic carbon entrapment in sediment, where as low δ15N 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

  13. Temporal patterns in the soundscape of the shallow waters of a Mediterranean marine protected area

    NASA Astrophysics Data System (ADS)

    Buscaino, Giuseppa; Ceraulo, Maria; Pieretti, Nadia; Corrias, Valentina; Farina, Almo; Filiciotto, Francesco; Maccarrone, Vincenzo; Grammauta, Rosario; Caruso, Francesco; Giuseppe, Alonge; Mazzola, Salvatore

    2016-09-01

    The study of marine soundscapes is an emerging field of research that contributes important information about biological compositions and environmental conditions. The seasonal and circadian soundscape trends of a marine protected area (MPA) in the Mediterranean Sea have been studied for one year using an autonomous acoustic recorder. Frequencies less than 1 kHz are dominated by noise generated by waves and are louder during the winter; conversely, higher frequencies (4–96 kHz) are dominated by snapping shrimp, which increase their acoustic activity at night during the summer. Fish choruses, below 2 kHz, characterize the soundscape at sunset during the summer. Because there are 13 vessel passages per hour on average, causing acoustic interference with fish choruses 46% of the time, this MPA cannot be considered to be protected from noise. On the basis of the high seasonal variability of the soundscape components, this study proposes a one-year acoustic monitoring protocol using the soundscape methodology approach and discusses the concept of MPA size.

  14. Temporal patterns in the soundscape of the shallow waters of a Mediterranean marine protected area

    PubMed Central

    Buscaino, Giuseppa; Ceraulo, Maria; Pieretti, Nadia; Corrias, Valentina; Farina, Almo; Filiciotto, Francesco; Maccarrone, Vincenzo; Grammauta, Rosario; Caruso, Francesco; Giuseppe, Alonge; Mazzola, Salvatore

    2016-01-01

    The study of marine soundscapes is an emerging field of research that contributes important information about biological compositions and environmental conditions. The seasonal and circadian soundscape trends of a marine protected area (MPA) in the Mediterranean Sea have been studied for one year using an autonomous acoustic recorder. Frequencies less than 1 kHz are dominated by noise generated by waves and are louder during the winter; conversely, higher frequencies (4–96 kHz) are dominated by snapping shrimp, which increase their acoustic activity at night during the summer. Fish choruses, below 2 kHz, characterize the soundscape at sunset during the summer. Because there are 13 vessel passages per hour on average, causing acoustic interference with fish choruses 46% of the time, this MPA cannot be considered to be protected from noise. On the basis of the high seasonal variability of the soundscape components, this study proposes a one-year acoustic monitoring protocol using the soundscape methodology approach and discusses the concept of MPA size. PMID:27677956

  15. Gender differences in speech temporal patterns detected using lagged co-occurrence text-analysis of personal narratives.

    PubMed

    Cohen, Shuki J

    2009-03-01

    This paper describes a novel methodology for the detection of speech patterns. Lagged co-occurrence analysis (LCA) utilizes the likelihood that a target word will be uttered in a certain position after a trigger word. Using this methodology, it is possible to uncover a statistically significant repetitive temporal patterns of word use, compared to a random choice of words. To demonstrate this new tool on autobiographical narratives, 200 subjects related each a 5-min story, and these stories were transcribed and subjected to LCA, using software written by the author. This study focuses on establishing the usefulness of LCA in psychological research by examining its associations with gender. The application of LCA to the corpus of personal narratives revealed significant differences in the temporal patterns of using the word "I" between male and female speakers. This finding is particularly demonstrative of the potential for studying speech temporal patterns using LCA, as men and women tend to utter the pronoun "I" in comparable frequencies. Specifically, LCA of the personal narratives showed that, on average, men tended to have shorter interval between their use of the pronoun, while women speak longer between two subsequent utterances of the pronoun. The results of this study are discussed in light of psycholinguistic factors governing male and female speech communities.

  16. Temporal Variability and Stability in Infant-Directed Sung Speech: Evidence for Language-Specific Patterns

    ERIC Educational Resources Information Center

    Falk, Simone

    2011-01-01

    In this paper, sung speech is used as a methodological tool to explore temporal variability in the timing of word-internal consonants and vowels. It is hypothesized that temporal variability/stability becomes clearer under the varying rhythmical conditions induced by song. This is explored cross-linguistically in German--a language that exhibits a…

  17. Spatio-Temporal Patterns of Schistosomiasis Japonica in Lake and Marshland Areas in China: The Effect of Snail Habitats

    PubMed Central

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

    2014-01-01

    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 temporal pattern analysis applied to the study of rat behavior in the elevated plus maze: methodological and conceptual highlights.

    PubMed

    Casarrubea, M; Magnusson, M S; Roy, V; Arabo, A; Sorbera, F; Santangelo, A; Faulisi, F; Crescimanno, G

    2014-08-30

    Aim of this article is to illustrate the application of a multivariate approach known as t-pattern analysis in the study of rat behavior in elevated plus maze. By means of this multivariate approach, significant relationships among behavioral events in the course of time can be described. Both quantitative and t-pattern analyses were utilized to analyze data obtained from fifteen male Wistar rats following a trial 1-trial 2 protocol. In trial 2, in comparison with the initial exposure, mean occurrences of behavioral elements performed in protected zones of the maze showed a significant increase counterbalanced by a significant decrease of mean occurrences of behavioral elements in unprotected zones. Multivariate t-pattern analysis, in trial 1, revealed the presence of 134 t-patterns of different composition. In trial 2, the temporal structure of behavior become more simple, being present only 32 different t-patterns. Behavioral strings and stripes (i.e. graphical representation of each t-pattern onset) of all t-patterns were presented both for trial 1 and trial 2 as well. Finally, percent distributions in the three zones of the maze show a clear-cut increase of t-patterns in closed arm and a significant reduction in the remaining zones. Results show that previous experience deeply modifies the temporal structure of rat behavior in the elevated plus maze. In addition, this article, by highlighting several conceptual, methodological and illustrative aspects on the utilization of t-pattern analysis, could represent a useful background to employ such a refined approach in the study of rat behavior in elevated plus maze.

  19. Microbial respiration and root respiration follow divergent seasonal and diel temporal patterns in a temperate forest

    NASA Astrophysics Data System (ADS)

    Davidson, E. A.; Savage, K. E.; Tang, J.

    2010-12-01

    Soil respiration is often related to empirical measurements of soil temperature and water content, as if it were a single process that responds uniformly to these environmental drivers. However, we know that root and microbial processes both contribute to CO2 production within the soil, and the roots are connected to aboveground plant tissues, which may, in turn, be responding to other environmental cues. Trenched plots provide a method to separate these two processes, where only microbial respiration (Rm) occurs in the trenched plots that have had roots excluded, total soil respiration (Rt) occurs in untrenched reference plots, and root respiration (Rr) is inferred by the difference between the two treatments. Like all methods, this one has potential artifacts that may render the quantification of Rr uncertain, but the method is likely to demonstrate the phenology of Rr and its impact on diel and seasonal temporal patterns of Rt. We deployed three automated soil respiration chambers in both control and trenched plots at the Harvard Forest in central Massachusetts. Soil CO2 efflux was measured every half hour for each chamber from day-of-year 112 to 304, 2009 (with some data gaps in the intervening period due to equipment failure). For the combined measurement period, mean daily soil respiration and mean daily flux amplitude were significantly higher in the reference plots compared to the trenched plots. The peak flux also occurred about 2 hours later in the evening in the reference plots compared to the trenched plots. Breaking this period down into four seasonal windows (spring, early summer, late summer, and autumn), the mean daily flux was significantly higher in the reference plot for all seasons, the higher daily amplitude was significant only during the early summer, and the delay in peak emissions was significant during early and late summer. While roots were contributing to soil respiration in all measurement periods, their largest effect on daily mean

  20. Near-Real-Time Acoustic Monitoring of Beaked Whales and Other Cetaceans Using a Seaglider(TM)

    DTIC Science & Technology

    2012-05-18

    and Cuvier’s beaked whale [8], Longman’s beaked whale [27], and an unidentified beaked whale species recorded offshore Hawai’i at Cross Seamount [28,29...S, et al. (2008) Temporal patterns in the acoustic signals of beaked whales at Cross Seamount . Biology Letters 4: 208–211. 29. McDonald MA, Hildebrand...JA, Wiggins SM, Johnston DW, Polovina JJ (2009) An acoustic survey of beaked whales at Cross Seamount near Hawaii. Journal of the Acoustical Society

  1. Temporal discharge patterns evoked by rapid sequences of wide- and narrowband clicks in the primary auditory cortex of cat.

    PubMed

    Lu, T; Wang, X

    2000-07-01

    The present study investigated neural responses to rapid, repetitive stimuli in the primary auditory cortex (A1) of cats. We focused on two important issues regarding cortical coding of sequences of stimuli: temporal discharge patterns of A1 neurons as a function of inter-stimulus interval and cortical mechanisms for representing successive stimulus events separated by very short intervals. These issues were studied using wide- and narrowband click trains with inter-click intervals (ICIs) ranging from 3 to 100 ms as a class of representative sequential stimuli. The main findings of this study are 1) A1 units displayed, in response to click train stimuli, three distinct temporal discharge patterns that we classify as regions I, II, and III. At long ICIs nearly all A1 units exhibited typical stimulus-synchronized response patterns (region I) consistent with previously reported observations. At intermediate ICIs, no clear temporal structures were visible in the responses of most A1 units (region II). At short ICIs, temporal discharge patterns are characterized by the presence of either intrinsic oscillations (at approximately 10 Hz) or a change in discharge rate that was a monotonically decreasing function of ICI (region III). In some A1 units, temporal discharge patterns corresponding to region III were absent. 2) The boundary between regions I and II (synchronization boundary) had a median value of 39.8 ms ICI ([25%, 75%] = [20.4, 58. 8] ms ICI; n = 131). The median boundary between regions II and III was estimated at 6.3 ms ([25%, 75%] = [5.2, 9.7] ms ICI; n = 47) for units showing rate changes (rate-change boundary). 3) The boundary values between different regions appeared to be relatively independent of stimulus intensity (at modest sound levels) or the bandwidth of the clicks used. 4) There is a weak correlation between a unit's synchronization boundary and its response latency. Units with shorter latencies appeared to also have smaller boundary values. And 5

  2. Acoustic pattern evaluation during cementless hip arthroplasty surgery may be a new method for predicting complications

    PubMed Central

    Morohashi, Itaru; Iwase, Hideaki; Kanda, Akio; Sato, Taichi; Homma, Yasuhiro; Mogami, Atsuhiko; Obayashi, Osamu; Kaneko, Kazuo

    2017-01-01

    Background: Although surgeons must perform implantation of the cementless stem during total hip arthroplasty (THA) without complications, assessment is left to the surgeon’s intuitive judgement, which could contain inter/intra-observer bias variety. We therefore asked (1) whether the sound created during the stem implantation could be evaluated objectively and (2) whether those sounds are correlate to the complication specific to the cementless stems. Our hypothesis is that the sounds produced during stem insertion could be quantified and related to the complications. Patients and method: In 71 THAs, we quantified the sound produced during stem insertion and investigated the relationship between these sounds and the occurrence of intraoperative fracture and subsidence. Results: The sound data were divided into two patterns: Patterns A and B. The difference between the peak value (dB) at the most common frequency (near 7 kHz) and the second most common frequency (near 4 kHz) of strikes during the final phase of implantation in Patterns A and B showed a significant difference. Adverse events on intraoperative fracture and subsidence were significantly less common in patients with Pattern A than in those with Pattern B (six of 42 hips with Pattern A and 13 of 29 hips with Pattern B, p = 0.004). Pattern A in predicting a clinical course without those adverse events was 69.2% and the specificity was 68.4%. Positive and negative predictive values were 85.7% and 44.8%, respectively. Conclusion: The sound generated during stem insertion was quantified. Those sound patterns were associated with complications. PMID:28186872

  3. A MyoD-generated feed-forward circuit temporally patterns gene expression during skeletal muscle differentiation

    PubMed Central

    Penn, Bennett H.; Bergstrom, Donald A.; Dilworth, F. Jeffrey; Bengal, Eyal; Tapscott, Stephen J.

    2004-01-01

    The development and differentiation of distinct cell types is achieved through the sequential expression of subsets of genes; yet, the molecular mechanisms that temporally pattern gene expression remain largely unknown. In skeletal myogenesis, gene expression is initiated by MyoD and includes the expression of specific Mef2 isoforms and activation of the p38 mitogen-activated protein kinase (MAPK) pathway. Here, we show that p38 activity facilitates MyoD and Mef2 binding at a subset of late-activated promoters, and the binding of Mef2D recruits Pol II. Most importantly, expression of late-activated genes can be shifted to the early stages of differentiation by precocious activation of p38 and expression of Mef2D, demonstrating that a MyoD-mediated feed-forward circuit temporally patterns gene expression. PMID:15466486

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

    NASA Astrophysics Data System (ADS)

    Goldfinger, C.

    2011-12-01

    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.

  5. Frequency and time pattern differences in acoustic signals produced by Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) in stored maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The acoustic signals emitted by the last stage larval instars and adults of Prostephanus truncatus and Sitophilus zeamais in stored maize were investigated. Analyses were performed to identify brief, 1-10-ms broadband sound impulses of five different frequency patterns produced by larvae and adults,...

  6. Two-level hierarchy with sparsely and temporally coded patterns and its possible functional role in information processing.

    PubMed

    Nomura, Masaki; Aoyagi, Toshio; Okada, Masato

    2003-09-01

    We study the stability of two types of mixed states in an oscillator neural network model. Patterns to be stored are represented by complex variables whose amplitudes are either 0 (silent state) or 1 (firing state) and whose phases represent the timing of firing. The mixed states are defined in terms of a certain type of average over some specified number s of memory patterns. We define two types of such mixed states, each of which corresponds to a different type of restriction placed on this set of s memory patterns. The stability of each type is investigated both theoretically and numerically. We find that only one type of a mixed state, which consists of temporally correlated patterns, is stable. Finally, we discuss a possible functional role of such mixed states in information processing.

  7. High-order space-time finite element schemes for acoustic and viscodynamic wave equations with temporal decoupling.

    PubMed

    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

    2014-04-13

    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 [Formula: see text] 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.

  8. 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

  9. Spatial and Temporal Variability of Zooplankton Thin Layers: The Effects of Composition and Orientation on Acoustic Detection of Layers

    DTIC Science & Technology

    2010-09-30

    zooplankton . We saw many images that contained multiple copepods and delicate gelatinous taxa such as larvaceans and medusae (Figures 7 and 8). Images of...1 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. Spatial and Temporal Variability of Zooplankton Thin...understand the physical and biological mechanisms of formation and maintenance of thin layers of zooplankton . Because zooplankton can be strong sound

  10. T-pattern analysis for the study of temporal structure of animal and human behavior: a comprehensive review.

    PubMed

    Casarrubea, M; Jonsson, G K; Faulisi, F; Sorbera, F; Di Giovanni, G; Benigno, A; Crescimanno, G; Magnusson, M S

    2015-01-15

    A basic tenet in the realm of modern behavioral sciences is that behavior consists of patterns in time. For this reason, investigations of behavior deal with sequences that are not easily perceivable by the unaided observer. This problem calls for improved means of detection, data handling and analysis. This review focuses on the analysis of the temporal structure of behavior carried out by means of a multivariate approach known as T-pattern analysis. Using this technique, recurring sequences of behavioral events, usually hard to detect, can be unveiled and carefully described. T-pattern analysis has been successfully applied in the study of various aspects of human or animal behavior such as behavioral modifications in neuro-psychiatric diseases, route-tracing stereotypy in mice, interaction between human subjects and animal or artificial agents, hormonal-behavioral interactions, patterns of behavior associated with emesis and, in our laboratories, exploration and anxiety-related behaviors in rodents. After describing the theory and concepts of T-pattern analysis, this review will focus on the application of the analysis to the study of the temporal characteristics of behavior in different species from rodents to human beings. This work could represent a useful background for researchers who intend to employ such a refined multivariate approach to the study of behavior.

  11. Associative-memory representations emerge as shared spatial patterns of theta activity spanning the primate temporal cortex

    PubMed Central

    Nakahara, Kiyoshi; Adachi, Ken; Kawasaki, Keisuke; Matsuo, Takeshi; Sawahata, Hirohito; Majima, Kei; Takeda, Masaki; Sugiyama, Sayaka; Nakata, Ryota; Iijima, Atsuhiko; Tanigawa, Hisashi; Suzuki, Takafumi; Kamitani, Yukiyasu; Hasegawa, Isao

    2016-01-01

    Highly localized neuronal spikes in primate temporal cortex can encode associative memory; however, whether memory formation involves area-wide reorganization of ensemble activity, which often accompanies rhythmicity, or just local microcircuit-level plasticity, remains elusive. Using high-density electrocorticography, we capture local-field potentials spanning the monkey temporal lobes, and show that the visual pair-association (PA) memory is encoded in spatial patterns of theta activity in areas TE, 36, and, partially, in the parahippocampal cortex, but not in the entorhinal cortex. The theta patterns elicited by learned paired associates are distinct between pairs, but similar within pairs. This pattern similarity, emerging through novel PA learning, allows a machine-learning decoder trained on theta patterns elicited by a particular visual item to correctly predict the identity of those elicited by its paired associate. Our results suggest that the formation and sharing of widespread cortical theta patterns via learning-induced reorganization are involved in the mechanisms of associative memory representation. PMID:27282247

  12. 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.

  13. Understanding spatio-temporal mobility patterns for seniors, child/student and adult using smart card data

    NASA Astrophysics Data System (ADS)

    Huang, X.; Tan, J.

    2014-11-01

    Commutes in urban areas create interesting travel patterns that are often stored in regional transportation databases. These patterns can vary based on the day of the week, the time of the day, and commuter type. This study proposes methods to detect underlying spatio-temporal variability among three groups of commuters (senior citizens, child/students, and adults) using data mining and spatial analytics. Data from over 36 million individual trip records collected over one week (March 2012) on the Singapore bus and Mass Rapid Transit (MRT) system by the fare collection system were used. Analyses of such data are important for transportation and landuse designers and contribute to a better understanding of urban dynamics. Specifically, descriptive statistics, network analysis, and spatial analysis methods are presented. Descriptive variables were proposed such as density and duration to detect temporal features of people. A directed weighted graph G ≡ (N , L, W) was defined to analyze the global network properties of every pair of the transportation link in the city during an average workday for all three categories. Besides, spatial interpolation and spatial statistic tools were used to transform the discrete network nodes into structured human movement landscape to understand the role of transportation systems in urban areas. The travel behaviour of the three categories follows a certain degree of temporal and spatial universality but also displays unique patterns within their own specialties. Each category is characterized by their different peak hours, commute distances, and specific locations for travel on weekdays.

  14. 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

  15. Temporal pattern in the effect of postnatal blood lead level on intellectual development of young children.

    PubMed

    Schnaas, L; Rothenberg, S J; Perroni, E; Martínez, S; Hernández, C; Hernández, R M

    2000-01-01

    To determine the temporal pattern of the effect of postnatal blood lead level on the General Cognitive Index (GCI) of the McCarthy Scales of Children's Abilities, we used data from 112 children of the Mexico City Prospective Lead Study with complete evaluations from 36 to 60 months of age at 6-month intervals. We measured blood lead level every 6 months from 6 to 54 months. We controlled for 5-min Apgar, birth weight, birth order, sex, socioeconomic level, maternal IQ, and maximum maternal educational level in a repeated measures ANCOVA using child blood lead level grouped by 6-18 month (geometric mean 10.1 microg/dl, range 3.5-37.0 microg/dl), 24-36 month (geometric mean 9.7 microg/dl, range 3.0-42.7 microg/dl), and 42-54 month (geometric mean 8.4 microg/dl, range 2.5-44.8 microg/dl) averages. There were significant interactions between the 6-18 month blood lead level and age with GCI as the endpoint and between 24-36 month blood lead level and age. The regression coefficient of blood lead at 6-18 months became more negative with age until 48 months, when the rate of decline moderated (linear polynomial contrast p=0. 047). The regression coefficient of blood lead at 24-36 months with CGI became more negative as well from 36 to 48 months but then started decreasing toward zero from 48 to 60 months (quadratic polynomial contrast p=0.019). Significant between-subjects lead effects on GCI were found for 24-36 month blood lead level at 48 months (p=0.021) and at 54 months (p=0.073). The greatest effect (at 48 months) was a 5.8-point GCI decrease with each natural log unit increase in blood lead. Significant between-subjects lead effects on GCI were found for 42-54 month blood lead level at 54 months (p=0. 040) and at 60 months (p=0.060). The effect of postnatal blood lead level on GCI reaches its maximum approximately 1-3 years later, and then becomes less evident. Four to five years of age appears to be a critical period for the manifestation of the earlier postnatal

  16. Spatio-temporal distribution patterns of the epibenthic community in the coastal waters of Suriname

    NASA Astrophysics Data System (ADS)

    Willems, Tomas; De Backer, Annelies; Wan Tong You, Kenneth; Vincx, Magda; Hostens, Kris

    2015-10-01

    This study aimed to characterize the spatio-temporal patterns of the epibenthic community in the coastal waters of Suriname. Data were collected on a (bi)monthly basis in 2012-2013 at 15 locations in the shallow (<40 m) coastal area, revealing three spatially distinct species assemblages, related to clear gradients in some environmental parameters. A species-poor coastal assemblage was discerned within the muddy, turbid-water zone (6-20 m depth), dominated by Atlantic seabob shrimp Xiphopenaeus kroyeri (Crustacea: Penaeoidea). Near the 30 m isobath, sediments were much coarser (median grain size on average 345±103 μm vs. 128±53 μm in the coastal assemblage) and water transparency was much higher (on average 7.6±3.5 m vs. 2.4±2.1 m in the coastal assemblage). In this zone, a diverse offshore assemblage was found, characterized by brittle stars (mainly Ophioderma brevispina and Ophiolepis elegans) and a variety of crabs, sea stars and hermit crabs. In between both zones, a transition assemblage was noted, with epibenthic species typically found in either the coastal or offshore assemblages, but mainly characterized by the absence of X. kroyeri. Although the epibenthic community was primarily structured in an on-offshore gradient related to depth, sediment grain size and sediment total organic carbon content, a longitudinal (west-east) gradient was apparent as well. The zones in the eastern part of the Suriname coastal shelf seemed to be more widely stretched along the on-offshore gradient. Although clear seasonal differences were noted in the environmental characteristics (e.g. dry vs. rainy season), this was not reflected in the epibenthic community structure. X. kroyeri reached very high densities (up to 1383 ind 1000 m-²) in the shallow coastal waters of Suriname. As X. kroyeri is increasingly exploited throughout its range, the current study provides the ecological context for its presence and abundance, which is crucial for an ecosystem approach and the

  17. Spatial-temporal excess mortality patterns of the 1918–1919 influenza pandemic in Spain

    PubMed Central

    2014-01-01

    Background The impact of socio-demographic factors and baseline health on the mortality burden of seasonal and pandemic influenza remains debated. Here we analyzed the spatial-temporal mortality patterns of the 1918 influenza pandemic in Spain, one of the countries of Europe that experienced the highest mortality burden. Methods We analyzed monthly death rates from respiratory diseases and all-causes across 49 provinces of Spain, including the Canary and Balearic Islands, during the period January-1915 to June-1919. We estimated the influenza-related excess death rates and risk of death relative to baseline mortality by pandemic wave and province. We then explored the association between pandemic excess mortality rates and health and socio-demographic factors, which included population size and age structure, population density, infant mortality rates, baseline death rates, and urbanization. Results Our analysis revealed high geographic heterogeneity in pandemic mortality impact. We identified 3 pandemic waves of varying timing and intensity covering the period from Jan-1918 to Jun-1919, with the highest pandemic-related excess mortality rates occurring during the months of October-November 1918 across all Spanish provinces. Cumulative excess mortality rates followed a south–north gradient after controlling for demographic factors, with the North experiencing highest excess mortality rates. A model that included latitude, population density, and the proportion of children living in provinces explained about 40% of the geographic variability in cumulative excess death rates during 1918–19, but different factors explained mortality variation in each wave. Conclusions A substantial fraction of the variability in excess mortality rates across Spanish provinces remained unexplained, which suggests that other unidentified factors such as comorbidities, climate and background immunity may have affected the 1918–19 pandemic mortality rates. Further archeo

  18. Spatio-Temporal Patterns of Demyelination and Remyelination in the Cuprizone Mouse Model

    PubMed Central

    Tagge, Ian; O’Connor, Audrey; Chaudhary, Priya; Pollaro, Jim; Berlow, Yosef; Chalupsky, Megan; Bourdette, Dennis; Woltjer, Randy; Johnson, Mac; Rooney, William

    2016-01-01

    Cuprizone administration in mice provides a reproducible model of demyelination and spontaneous remyelination, and has been useful in understanding important aspects of human disease, including multiple sclerosis. In this study, we apply high spatial resolution quantitative MRI techniques to establish the spatio-temporal patterns of acute demyelination in C57BL/6 mice after 6 weeks of cuprizone administration, and subsequent remyelination after 6 weeks of post-cuprizone recovery. MRI measurements were complemented with Black Gold II stain for myelin and immunohistochemical stains for associated tissue changes. Gene expression was evaluated using the Allen Gene Expression Atlas. Twenty-five C57BL/6 male mice were split into control and cuprizone groups; MRI data were obtained at baseline, after 6 weeks of cuprizone, and 6 weeks post-cuprizone. High-resolution (100μm isotropic) whole-brain coverage magnetization transfer ratio (MTR) parametric maps demonstrated concurrent caudal-to-rostral and medial-to-lateral gradients of MTR decrease within corpus callosum (CC) that correlated well with demyelination assessed histologically. Our results show that demyelination was not limited to the midsagittal line of the corpus callosum, and also that opposing gradients of demyelination occur in the lateral and medial CC. T2-weighted MRI gray/white matter contrast was strong at baseline, weak after 6 weeks of cuprizone treatment, and returned to a limited extent after recovery. MTR decreases during demyelination were observed throughout the brain, most clearly in callosal white matter. Myelin damage and repair appear to be influenced by proximity to oligodendrocyte progenitor cell populations and exhibit an inverse correlation with myelin basic protein gene expression. These findings suggest that susceptibility to injury and ability to repair vary across the brain, and whole-brain analysis is necessary to accurately characterize this model. Whole-brain parametric mapping across

  19. Spatial and temporal patterns of Pleistocene biogenic sediment accumulation in the Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Moy, C. M.; Bahlburg, H.; Childress, L. B.; Cowan, E. A.; Forwick, M.; Müller, J.; Ribeiro, F.; Ridgway, K. D.; Mix, A. C.

    2013-12-01

    Reconstructing the timing and nature of past changes in aquatic productivity in the Gulf of Alaska (GoA) can shed light on the primary processes driving biogeochemical cycling over geologic timescales. Today, Fe is an important micronutrient that limits primary productivity in surface waters beyond the continental shelf in much of the GoA. However, we have a relatively poor understanding of how Fe-delivery processes, combined with changing climate, environmental, and oceanographic conditions, interact to influence primary production over glacial-interglacial timescales. An important first step is to identify the spatial and temporal patterns of increased productivity in the sediment record. Here, we present sedimentologic and physical property data from IODP Expedition 341 and identify intervals where diatom ooze and diatom-rich mud lithofacies are prevalent during the Pleistocene. Among the Expedition 341 recovered cores, were high-recovery intervals in the outer (Site U1417) and inner (U1418) Surveyor Fan, and from a small slope basin at the edge of the continental shelf (Site U1419). In general, greenish gray diatomaceous ooze (containing >50 % diatoms in smear slides) and diatom-rich mud (>25% diatoms) is found in beds ranging in thickness from 20 to 150 cm, interbedded with gray mud that commonly contains lonestones. Ooze is occasionally found immediately overlying volcanic ash. Compared to non-biogenic mud, diatomaceous sediments are generally characterized by lower magnetic susceptibility, natural gamma ray, bulk density, and higher b* color reflectance. At Site U1417, we observe a frequent occurrence of diatomaceous ooze during the middle Pleistocene relative to the early and late Pleistocene. At Site U1418, intervals containing diatom ooze are less common than at U1417 and biogenic sediments are mainly observed within the late Pleistocene portion of the record. However, higher sedimentation rates at U1418 relative to U1417, and the co-occurrence of sand

  20. 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.

  1. Classification of Hazelnut Kernels by Using Impact Acoustic Time-Frequency Patterns

    NASA Astrophysics Data System (ADS)

    Kalkan, Habil; Ince, Nuri Firat; Tewfik, Ahmed H.; Yardimci, Yasemin; Pearson, Tom

    2007-12-01

    Hazelnuts with damaged or cracked shells are more prone to infection with aflatoxin producing molds ( Aspergillus flavus). These molds can cause cancer. In this study, we introduce a new approach that separates damaged/cracked hazelnut kernels from good ones by using time-frequency features obtained from impact acoustic signals. The proposed technique requires no prior knowledge of the relevant time and frequency locations. In an offline step, the algorithm adaptively segments impact signals from a training data set in time using local cosine packet analysis and a Kullback-Leibler criterion to assess the discrimination power of different segmentations. In each resulting time segment, the signal is further decomposed into subbands using an undecimated wavelet transform. The most discriminative subbands are selected according to the Euclidean distance between the cumulative probability distributions of the corresponding subband coefficients. The most discriminative subbands are fed into a linear discriminant analysis classifier. In the online classification step, the algorithm simply computes the learned features from the observed signal and feeds them to the linear discriminant analysis (LDA) classifier. The algorithm achieved a throughput rate of 45 nuts/s and a classification accuracy of 96% with the 30 most discriminative features, a higher rate than those provided with prior methods.

  2. Acoustic assessment of species richness and assembly rules in ensiferan communities from temperate ecosystems.

    PubMed

    Roca, Irene T; Proulx, Raphaël

    2016-01-01

    Vocalizing animals are known to produce a wide range of species-specific spectral and temporal communication patterns. As a consequence, the acoustic heterogeneity of insect communities is expected to increase with the number of vocalizing species. Using a combination of simulation models and field surveys, we tested the hypotheses that (1) acoustic heterogeneity increases with the number of cricket and katydid species in ensiferan communities and (2) acoustic heterogeneity of naturally assembled ensiferan communities is higher than that of randomly assembled ones. The slope of the acoustic heterogeneity--species richness relationship in naturally assembled communities was positive but did not differ from that of randomly assembled communities, suggesting a rather weak competition for the acoustic space. Comparing the species richness-acoustic heterogeneity relationship of naturally and randomly assembled communities, our study provides a novel approach for understanding species assembly rules in animal groups that rely on acoustic communication.

  3. Variability in Regularity: Mining Temporal Mobility Patterns in London, Singapore and Beijing Using Smart-Card Data

    PubMed Central

    Zhong, Chen; Batty, Michael; Manley, Ed; Wang, Jiaqiu; Wang, Zijia; Chen, Feng; Schmitt, Gerhard

    2016-01-01

    To discover regularities in human mobility is of fundamental importance to our understanding of urban dynamics, and essential to city and transport planning, urban management and policymaking. Previous research has revealed universal regularities at mainly aggregated spatio-temporal scales but when we zoom into finer scales, considerable heterogeneity and diversity is observed instead. The fundamental question we address in this paper is at what scales are the regularities we detect stable, explicable, and sustainable. This paper thus proposes a basic measure of variability to assess the stability of such regularities focusing mainly on changes over a range of temporal scales. We demonstrate this by comparing regularities in the urban mobility patterns in three world cities, namely London, Singapore and Beijing using one-week of smart-card data. The results show that variations in regularity scale as non-linear functions of the temporal resolution, which we measure over a scale from 1 minute to 24 hours thus reflecting the diurnal cycle of human mobility. A particularly dramatic increase in variability occurs up to the temporal scale of about 15 minutes in all three cities and this implies that limits exist when we look forward or backward with respect to making short-term predictions. The degree of regularity varies in fact from city to city with Beijing and Singapore showing higher regularity in comparison to London across all temporal scales. A detailed discussion is provided, which relates the analysis to various characteristics of the three cities. In summary, this work contributes to a deeper understanding of regularities in patterns of transit use from variations in volumes of travellers entering subway stations, it establishes a generic analytical framework for comparative studies using urban mobility data, and it provides key points for the management of variability by policy-makers intent on for making the travel experience more amenable. PMID:26872333

  4. Variability in Regularity: Mining Temporal Mobility Patterns in London, Singapore and Beijing Using Smart-Card Data.

    PubMed

    Zhong, Chen; Batty, Michael; Manley, Ed; Wang, Jiaqiu; Wang, Zijia; Chen, Feng; Schmitt, Gerhard

    2016-01-01

    To discover regularities in human mobility is of fundamental importance to our understanding of urban dynamics, and essential to city and transport planning, urban management and policymaking. Previous research has revealed universal regularities at mainly aggregated spatio-temporal scales but when we zoom into finer scales, considerable heterogeneity and diversity is observed instead. The fundamental question we address in this paper is at what scales are the regularities we detect stable, explicable, and sustainable. This paper thus proposes a basic measure of variability to assess the stability of such regularities focusing mainly on changes over a range of temporal scales. We demonstrate this by comparing regularities in the urban mobility patterns in three world cities, namely London, Singapore and Beijing using one-week of smart-card data. The results show that variations in regularity scale as non-linear functions of the temporal resolution, which we measure over a scale from 1 minute to 24 hours thus reflecting the diurnal cycle of human mobility. A particularly dramatic increase in variability occurs up to the temporal scale of about 15 minutes in all three cities and this implies that limits exist when we look forward or backward with respect to making short-term predictions. The degree of regularity varies in fact from city to city with Beijing and Singapore showing higher regularity in comparison to London across all temporal scales. A detailed discussion is provided, which relates the analysis to various characteristics of the three cities. In summary, this work contributes to a deeper understanding of regularities in patterns of transit use from variations in volumes of travellers entering subway stations, it establishes a generic analytical framework for comparative studies using urban mobility data, and it provides key points for the management of variability by policy-makers intent on for making the travel experience more amenable.

  5. Temporal patterns of deep brain stimulation generated with a true random number generator and the logistic equation: effects on CNS arousal in mice

    PubMed Central

    Quinkert, A. W.; Pfaff, D. W.

    2012-01-01

    Deep brain stimulation (DBS) has shown promise in the treatment of many neurological and psychiatric disorders as well as a disorder of consciousness, the minimally conscious state (MCS). In the clinic, DBS is always monotonic standard pulses; however, we have hypothesized that temporally patterned pulses might be more efficient in achieving desired behavioral responses. Here we present two experiments on DBS of the central thalamus to increase arousal, as measured by motor activity, and to affect the electroencephalogram (EEG). In the first, we optimized amplitude and frequency in standard stimulation of the central thalamus in intact mice. In the second, the optimized fixed frequency was compared to two alternative temporal patterns, chaotic and random, which were physically identical to each other and fixed frequency in all ways except temporal pattern. In both experiments and with all types of stimulation, DBS of the central thalamus increased arousal as measured by motor activity. These data also revealed that temporal patterning of pulses can modulate response to stimulation. That temporal patterns in DBS of the central thalamus were found to alter motor activity response implies possible usefulness of temporal patterns in DBS of other contexts. More investigation into exactly how temporally patterned stimulation may affect neuronal circuit dynamics is necessary. PMID:22285420

  6. Spatial and Temporal Patterns of Impervious Cover Relative to Watershed Stream Location

    EPA Science Inventory

    The influence of spatial pattern on ecological processes is a guiding principle of landscape ecology. The guiding principle of spatial pattern was used for a U.S. nationwide assessment of impervious cover (IC). Spatial pattern was measured by comparing IC concentration near strea...

  7. Coding Acoustic Metasurfaces.

    PubMed

    Xie, Boyang; Tang, Kun; Cheng, Hua; Liu, Zhengyou; Chen, Shuqi; Tian, Jianguo

    2017-02-01

    Coding acoustic metasurfaces can combine simple logical bits to acquire sophisticated functions in wave control. The acoustic logical bits can achieve a phase difference of exactly π and a perfect match of the amplitudes for the transmitted waves. By programming the coding sequences, acoustic metasurfaces with various functions, including creating peculiar antenna patterns and waves focusing, have been demonstrated.

  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. Alteration of consciousness via diverse photo-acoustic stimulatory patterns. Phenomenology and effect on salivary flow rate, alpha-amylase and total protein levels.

    PubMed

    Beck, Anita; Fábián, Gábor; Fejérdy, Pál; Krause, Wolf-Rainer; Hermann, Péter; Módos, Károly; Varga, Gábor; Fábián, Tibor Károly

    2015-12-01

    Long-term photo-acoustic stimulation is used for the induction of altered states of consciousness for both therapeutic and experimental purposes. Long-term photo-acoustic stimulation also leads to changes in the composition of saliva which have a key contribution to the efficiency of this technique in easing mucosal symptoms of oral psychosomatic patients. The aim of this study is to find out whether there is any cumulative effect of repeated stimulation and whether there are any detectable differences between diverse stimulatory patterns of long lasting photo-acoustic stimulation on the phenomenology of the appearing trance state and on salivary secretion. There was significant cumulative effect in relation with the appearance of day dreaming as phenomenological parameter, and in relation with protein output and amylase/protein ratio as salivary parameter. Pattern specific effect was detectable in relation with salivary flow rate only. Although our results clearly indicate the existence of certain cumulative and stimulation-pattern specific effects of repeated photo-acoustic stimulation, the absolute values of all these effects were relatively small in this study. Therefore, in spite of their theoretical importance there are no direct clinical consequences of these findings. However, our data do not exclude at all the possibility that repeated stimulation with other stimulatory parameters may lead to more pronounced effects. Further studies are needed to make clear conclusion in this respect.

  10. Acoustic Analyses and Intelligibility Assessments of Timing Patterns among Chinese English Learners with Different Dialect Backgrounds

    ERIC Educational Resources Information Center

    Chen, Hsueh Chu

    2015-01-01

    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…

  11. Spatial and temporal pattern for the dentition in the Australian lungfish revealed with sonic hedgehog expression profile.

    PubMed

    Smith, Moya M; Okabe, Masataka; Joss, Jean

    2009-02-22

    We report a temporal order of tooth addition in the Australian lungfish where timing of tooth induction is sequential in the same pattern as osteichthyans along the lower jaw. The order of tooth initiation in Neoceratodus starts from the midline tooth, together with left and right ones at jaw position 2, followed by 3 and then 1. This is the pattern order for dentary teeth of several teleosts and what we propose represents a stereotypic initiation pattern shared with all osteichthyans, including the living sister group to all tetrapods, the Australian lungfish. This is contrary to previous opinions that the lungfish dentition is otherwise derived and uniquely different. Sonic hedgehog (shh) expression is intensely focused on tooth positions at different times corresponding with their initiation order. This deployment of shh is required for lungfish tooth induction, as cyclopamine treatment results in complete loss of these teeth when applied before they develop. The temporal sequence of tooth initiation is possibly regulated by shh and is know to be required for dentition pattern in other osteichthyans, including cichlid fish and snakes. This reflects a shared developmental process with jawed vertebrates at the level of the tooth module but differs with the lack of replacement teeth.

  12. Temporally coordinated signals progressively pattern the anteroposterior and dorsoventral body axes

    PubMed Central

    Tuazon, Francesca B; Mullins, Mary C

    2015-01-01

    The vertebrate body plan is established through the precise spatiotemporal coordination morphogen signaling pathways that pattern the anteroposterior (AP) and dorsoventral (DV) axes. Patterning along the AP axis is directed by posteriorizing signals Wnt, fibroblast growth factor (FGF), Nodal, and retinoic acid (RA), while patterning along the DV axis is directed by bone morphogenetic proteins (BMP) ventralizing signals. This review addresses the current understanding of how Wnt, FGF, RA and BMP pattern distinct AP and DV cell fates during early development and how their signaling mechanisms are coordinated to concomitantly pattern AP and DV tissues. PMID:26123688

  13. Complex temporal and spatial patterns in nonequilibrium processes. Final report, December 1, 1987--November 30, 1992

    SciTech Connect

    Not Available

    1992-12-31

    Dynamical systems methods have been used to study bifurcations and pattern formation in nonequilibrium systems. Accomplishments during this period include: information-theoretic methods for analyzing chaos, chemical reactors for studying sustained reaction-diffusion patterns, a reactor exploiting pattern formation to extract short- lived intermediate species, observation of bifurcation from periodic to quasiperiodic rotating chemical spiral patterns, observation of a Turing bifurcation (transition from uniform state to a stationary chemical pattern), method for extracting noise strength in ramped convection, self-similar fractal structure of Zn clusters in electrodeposition, and dynamical instability in crack propagation.

  14. Spatial and temporal patterns in bacterial abundance, production and viral infection in a temporarily open/closed southern African estuary

    NASA Astrophysics Data System (ADS)

    Allan, E. L.; Froneman, P. W.

    2008-05-01

    The spatial and temporal patterns in bacterial abundance, biomass, production, nanoflagellate abundance and the loss of bacterial production due to viral lysis were investigated in a temporarily open/closed estuary along the eastern seaboard of southern Africa over the period May 2006 to April 2007. Bacterial abundance, biomass and production ranged between 1.00 × 10 9 and 4.93 × 10 9 cells l -1, 32.43 and 108.59 μg C l -1 and 0.01 and 1.99 μg C l -1 h -1, respectively. With a few exceptions there were no significant spatial patterns in the values ( P > 0.05). Bacterial abundance, biomass and production, however, demonstrated a distinct temporal pattern with the lowest values consistently recorded during the winter months. Bacterial dynamics showed no effect of mouth opening events. Nanoflagellate and bacterial abundances were significantly correlated to one another ( P < 0.05) suggesting a strong predator-prey relationship. The frequency of visibly infected bacterial cells and the number of virus particles within each bacterial cell during the study demonstrated no significant temporal or spatial pattern ( P > 0.05) and ranged from 0.5 to 6.1% and 12.0 to 37.5 virus particles per bacterium, respectively. Viral infection and lysis was thus a constant source of bacterial mortality throughout the year. The estimated percentage of bacterial production removed by viral lysis ranged between 7.8 and 88.9% (mean = 30.3%) of the total which suggests that viral lysis represents a very important source of bacterial mortality during the study.

  15. Separation of spatial-temporal patterns ('climatic modes') by combined analysis of really measured and generated numerically vector time series

    NASA Astrophysics Data System (ADS)

    Feigin, A. M.; Mukhin, D.; Volodin, E. M.; Gavrilov, A.; Loskutov, E. M.

    2013-12-01

    The new method of decomposition of the Earth's climate system into well separated spatial-temporal patterns ('climatic modes') is discussed. The method is based on: (i) generalization of the MSSA (Multichannel Singular Spectral Analysis) [1] for expanding vector (space-distributed) time series in basis of spatial-temporal empirical orthogonal functions (STEOF), which makes allowance delayed correlations of the processes recorded in spatially separated points; (ii) expanding both real SST data, and longer by several times SST data generated numerically, in STEOF basis; (iii) use of the numerically produced STEOF basis for exclusion of 'too slow' (and thus not represented correctly) processes from real data. The application of the method allows by means of vector time series generated numerically by the INM RAS Coupled Climate Model [2] to separate from real SST anomalies data [3] two climatic modes possessing by noticeably different time scales: 3-5 and 9-11 years. Relations of separated modes to ENSO and PDO are investigated. Possible applications of spatial-temporal climatic patterns concept to prognosis of climate system evolution is discussed. 1. Ghil, M., R. M. Allen, M. D. Dettinger, K. Ide, D. Kondrashov, et al. (2002) "Advanced spectral methods for climatic time series", Rev. Geophys. 40(1), 3.1-3.41. 2. http://83.149.207.89/GCM_DATA_PLOTTING/GCM_INM_DATA_XY_en.htm 3. http://iridl.ldeo.columbia.edu/SOURCES/.KAPLAN/.EXTENDED/.v2/.ssta/

  16. Spatial and Temporal Patterns of Nitrogen Transport in a Subtropical Urban Coastal Watershed

    NASA Astrophysics Data System (ADS)

    Toor, G.; Banger, K.; Inglett, P.; Stanley, C.

    2010-12-01

    Non-point source pollution is the dominant pathway of nitrogen (N) transport in agriculture as well as urban watersheds. Very little is known about N transport in urban watersheds located in the subtropics. Our objective was to evaluate the spatial and temporal evolution patterns of N forms in streams draining sub-basins, ranging in size from 19 to 350 km2, of an urban watershed located in the Tampa Bay region. We used long-term monthly (1991-2009) and weekly (2009) stream water N concentration data collected from these sub-basins to evaluate the impact of urban development on N transport. Sub-basins were separated in two groups based on urban land uses: developed (18-24% residential, 1-14% built up) and undeveloped (3-11% residential, 1-3% built up). Mean monthly total N concentrations during 1991-2009 were 0.8-2.4 mg L-1 at all sites and were greatest in streams draining developed (1.7-2.4 mg L-1) than undeveloped (0.8-1.2 mg L-1) sub-basins. All the developed and undeveloped sub-basins had a narrow range of organic N concentration (0.60-0.77 mg L-1) in streams; however, percent organic N was about twice as much in streams draining undeveloped (66-71% of total N) than developed (30-44% of total N) sub-basins. On the other hand, both NO3-N concentration and percentage of total N were much greater in developed (0.89-1.66 mg L-1; 53-68% of total N) than undeveloped (0.21-0.37 mg L-1; 25-30% of total N) sub-basins. Among all N forms, mean monthly concentrations of NH4-N were lowest (<0.1 mg L-1; 2-5% of total N). Compared with long-term monthly total N concentrations, weekly total N concentrations were much higher (1.90-2.90 mg L-1) during 2009 high-flow period (June to September), with greater concentrations in developed (2.40-2.95 mg L-1) as compared to undeveloped (1.90-2.06 mg L-1) sub-basins. Concentrations of organic N mirrored a similar trend as total N at all sites. The weekly inorganic N (NO3-N, NH4-N) trends were similar to long-term data, with greater

  17. Spatial and temporal patterns of recent area change of glacier systems on the Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Cook, Alison; Murray, Tavi; Luckman, Adrian; Vaughan, David

    2013-04-01

    Glaciers on the Antarctic Peninsula (AP) have recently shown changes in extent, velocity and thickness. Understanding the response of glaciers to warming air temperatures and ocean circulation changes in this region is critical for understanding future mass balance changes, and yet there is little quantification of change in the mass balance of individual basins and the processes controlling changes in their extent. One reason for this is that the AP is a complex mountainous glacier system and without a topographic model at sufficient resolution the boundaries between individual glacier systems have been difficult to identify. With outlines it becomes possible to calculate changes in area and compare characteristics of individual glaciers. We present a new Digital Elevation Model (DEM) and a new drainage basin data set for the Antarctic Peninsula, along with an assessment of changes in area of marine-terminating glacier systems from the 1940s to 2010. We explain the methodology used in producing the new 100-m DEM of the region using ASTER GDEM, and the semi-automated drainage basin delineation method based on this DEM. This approach has resulted in outlines for 1598 glacier systems: these include outlet and mountain glaciers, ice caps, piedmonts, ice-covered islands and 'ice walls'. Of these, 903 are marine-terminating glaciers, all of which have coastal-change data at various time periods since the 1940s. Area calculations, along with other attributes, were assigned to individual basins, thus enabling comparative statistical analyses. We give a summary of these changes both by overall area change and by change in extent at 5-year time intervals, and describe patterns of ice loss both spatially (by latitude and by specific regions) and temporally (trends across time intervals). Although 90% of the 903 glaciers have reduced in size since the earliest recorded date, the area lost varies considerably between glaciers. Largest area loss has occurred to glaciers flowing

  18. Temporal patterns and source apportionment of nitrate-nitrogen leaching in a paddy field at Kelantan, Malaysia.

    PubMed

    Hussain, Hazilia; Yusoff, Mohd Kamil; Ramli, Mohd Firuz; Abd Latif, Puziah; Juahir, Hafizan; Zawawi, Mohamed Azwan Mohammed

    2013-11-15

    Nitrate-nitrogen leaching from agricultural areas is a major cause for groundwater pollution. Polluted groundwater with high levels of nitrate is hazardous and cause adverse health effects. Human consumption of water with elevated levels of NO3-N has been linked to the infant disorder methemoglobinemia and also to non-Hodgkin's disease lymphoma in adults. This research aims to study the temporal patterns and source apportionment of nitrate-nitrogen leaching in a paddy soil at Ladang Merdeka Ismail Mulong in Kelantan, Malaysia. The complex data matrix (128 x 16) of nitrate-nitrogen parameters was subjected to multivariate analysis mainly Principal Component Analysis (PCA) and Discriminant Analysis (DA). PCA extracted four principal components from this data set which explained 86.4% of the total variance. The most important contributors were soil physical properties confirmed using Alyuda Forecaster software (R2 = 0.98). Discriminant analysis was used to evaluate the temporal variation in soil nitrate-nitrogen on leaching process. Discriminant analysis gave four parameters (hydraulic head, evapotranspiration, rainfall and temperature) contributing more than 98% correct assignments in temporal analysis. DA allowed reduction in dimensionality of the large data set which defines the four operating parameters most efficient and economical to be monitored for temporal variations. This knowledge is important so as to protect the precious groundwater from contamination with nitrate.

  19. Poincare Plots and Symbolic Dynamics Patterns of Left Ventricular Function Parameters Extracted From Echocardiographic Acoustic Quantification

    DTIC Science & Technology

    2007-11-02

    N/A Dates Covered (from... to) - Title and Subtitle Poincare Plots and Symbolic Dynamics Patterns of Left Ventricular Function Parameters...IV. POINCARE ’ PLOTS ANALYSIS Poincarè plot analysis is a simple and robust graphical technique based on the analysis of the maps obtained by...Fortuin, et al. Ecocardiographic assessment of a normal adult aging population. Circulation 1977;56:273-278. [13] J.M. Gardin, W.L. Henry , D.D. Savage, J

  20. 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

  1. Spatio-temporal patterns of gun violence in Syracuse, New York 2009-2015

    PubMed Central

    Lane, Sandra; Jennings-Bey, Timothy; Haygood-El, Arnett; Brundage, Kim; Rubinstein, Robert A.

    2017-01-01

    Gun violence in the United States of America is a large public health problem that disproportionately affects urban areas. The epidemiology of gun violence reflects various aspects of an infectious disease including spatial and temporal clustering. We examined the spatial and temporal trends of gun violence in Syracuse, New York, a city of 145,000. We used a spatial scan statistic to reveal spatio-temporal clusters of gunshots investigated and corroborated by Syracuse City Police Department for the years 2009–2015. We also examined predictors of areas with increased gun violence using a multi-level zero-inflated Poisson regression with data from the 2010 census. Two space-time clusters of gun violence were revealed in the city. Higher rates of segregation, poverty and the summer months were all associated with increased risk of gun violence. Previous gunshots in the area were associated with a 26.8% increase in the risk of gun violence. Gun violence in Syracuse, NY is both spatially and temporally stable, with some neighborhoods of the city greatly afflicted. PMID:28319125

  2. TEMPORAL GENE INDUCTION PATTERNS IN SHEEPSHEAD MINNOWS EXPOSED TO 17-ESTRADIOL

    EPA Science Inventory

    Gene arrays provide a powerful method to examine changes in gene expression in fish due to chemical exposures in the environment. In this study, we expanded an existing gene array for sheepshead minnows (Cyprinodon variegatus) (SHM) and used it to examine temporal changes in gene...

  3. Spatio-temporal patterns of gun violence in Syracuse, New York 2009-2015.

    PubMed

    Larsen, David A; Lane, Sandra; Jennings-Bey, Timothy; Haygood-El, Arnett; Brundage, Kim; Rubinstein, Robert A

    2017-01-01

    Gun violence in the United States of America is a large public health problem that disproportionately affects urban areas. The epidemiology of gun violence reflects various aspects of an infectious disease including spatial and temporal clustering. We examined the spatial and temporal trends of gun violence in Syracuse, New York, a city of 145,000. We used a spatial scan statistic to reveal spatio-temporal clusters of gunshots investigated and corroborated by Syracuse City Police Department for the years 2009-2015. We also examined predictors of areas with increased gun violence using a multi-level zero-inflated Poisson regression with data from the 2010 census. Two space-time clusters of gun violence were revealed in the city. Higher rates of segregation, poverty and the summer months were all associated with increased risk of gun violence. Previous gunshots in the area were associated with a 26.8% increase in the risk of gun violence. Gun violence in Syracuse, NY is both spatially and temporally stable, with some neighborhoods of the city greatly afflicted.

  4. Spatio-temporal pattern of EEG in young brain respiration-training children.

    PubMed

    Kim, H R; Kim, S Y; Kim, D J; Kim, Y Y; Park, S K; Chae, J H; Kim, K S; Lee, K H; Lee, S H

    2001-01-01

    We have evaluated the effect of 'Brain Respiration' training on brain activity using Karhunen-Loeve (KL) decomposition as a method for spatio-temporal analysis of the electroencephalogram (EEG). BR training is a form of breath-work to optimize the function of the brain by concentrating Qi energy in the brain. Recently, BR-training has been reported to improve emotional maturity (i.e., EQ), short-term memory and intuition (Yoo et al., 1998). EEG data were taken during BR-training from 12 young BR-trainees (average age: 9.4 years) who had trained for 4 to 14 months, and during relaxation from age matched non-trained children. Spatio-temporal analysis showed a significant difference of EEG dynamics in right prefrontal, right inferior frontal, posterior temporal, parietal and occipital areas between BR-trainees and the control group. Amplitude of eigenvector components of BR-trainees in the areas of frontal, temporal and occipital cortex was larger than that of non-trained children (values were smaller in parietal cortex), with remarkably high amplitude alpha coherence all over the scalp. These results suggest that BR-training possibly activates brain function through changes in the activity of the frontal association area where higher mental integration and creative activities are mediated.

  5. 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 ...

  6. Intra-storm temporal patterns of rainfall in China using Huff curves 2251

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The intra-storm temporal distributions of precipitation are important to infiltration, runoff and erosion processes and models. A convenient and established method for characterizing precipitation hyetographs is with the use of Huff curves. In this study, 11,801 erosive rainfall events with one-mi...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Theory predicts that the temporal stability of productivity, measured as the ratio of the mean to the standard deviation of community biomass, increases with species richness and evenness. We used experimental species mixtures of grassland plants to test this hypothesis and identify the mechanisms i...

  8. 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.

  9. 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. PMID:26064641

  10. Temporal evolution of the chemical structure during the pattern transfer by ion-beam sputtering

    NASA Astrophysics Data System (ADS)

    Ha, N.-B.; Jeong, S.; Yu, S.; Ihm, H.-I.; Kim, J.-S.

    2015-01-01

    Ru films patterned by ion-beam sputtering (IBS) serve as sacrificial masks for the transfer of the patterns to Si(1 0 0) and metallic glass substrates by continued IBS. Under the same sputter condition, however, both bare substrates remain featureless. Chemical analyses of the individual nano structures simultaneously with the investigation of their morphological evolution reveal that the pattern transfer, despite its apparent success, suffers from premature degradation before the mask is fully removed by IBS. Moreover, the residue of the mask or Ru atoms stubbornly remains near the surface, resulting in unintended doping or alloying of both patterned substrates.

  11. Spatial and temporal patterns of chronic wasting disease: Fine-scale mapping of a wildlife epidemic in Wisconsin

    USGS Publications Warehouse

    Osnas, E.E.; Heisey, D.M.; Rolley, R.E.; Samuel, M.D.

    2009-01-01

    Emerging infectious diseases threaten wildlife populations and human health. Understanding the spatial distributions of these new diseases is important for disease management and policy makers; however, the data are complicated by heterogeneities across host classes, sampling variance, sampling biases, and the space-time epidemic process. Ignoring these issues can lead to false conclusions or obscure important patterns in the data, such as spatial variation in disease prevalence. Here, we applied hierarchical Bayesian disease mapping methods to account for risk factors and to estimate spatial and temporal patterns of infection by chronic wasting disease (CWD) in white-tailed deer (Odocoileus virginianus) of Wisconsin, USA. We found significant heterogeneities for infection due to age, sex, and spatial location. Infection probability increased with age for all young deer, increased with age faster for young males, and then declined for some older animals, as expected from disease-associated mortality and age-related changes in infection risk. We found that disease prevalence was clustered in a central location, as expected under a simple spatial epidemic process where disease prevalence should increase with time and expand spatially. However, we could not detect any consistent temporal or spatiotemporal trends in CWD prevalence. Estimates of the temporal trend indicated that prevalence may have decreased or increased with nearly equal posterior probability, and the model without temporal or spatiotemporal effects was nearly equivalent to models with these effects based on deviance information criteria. For maximum interpretability of the role of location as a disease risk factor, we used the technique of direct standardization for prevalence mapping, which we develop and describe. These mapping results allow disease management actions to be employed with reference to the estimated spatial distribution of the disease and to those host classes most at risk. Future

  12. Spatial and temporal patterns of endocrine active chemicals in small streams indicate differential exposure to aquatic organisms

    USGS Publications Warehouse

    Lee, K.E.; Barber, L.B.; Schoenfuss, H.L.

    2014-01-01

    Alkylphenolic chemicals (APCs) and hormones were measured six times from February through October 2007 in three Minnesota streams receiving wastewater to identify spatial and temporal patterns in concentrations and in estrogen equivalency. Fish were collected once during the study to evaluate endpoints indicative of endocrine disruption. The most commonly detected APCs were 4-tert-octylphenol and 4-nonylphenol and the most commonly detected hormones were estrone and androstenedione. Chemical concentrations were greatest for nonylphenol ethoxycarboxylates (NPECs) (5,000-140,000 ng/l), followed by 4-nonlylphenol and 4-nonylphenolethoxylates (50-880 ng/l), 4-tert-octylphenol and 4-tert-octylphenolethoxylates with concentrations as great as 130 ng/l, and hormones (0.1-54 ng/l). Patterns in chemicals and estrogen equivalency indicated that wastewater effluent is a pathway of APCs and hormones to downstream locations in this study. However, upstream contributions can be equally or more important indicating alternative sources. This study indicates that aquatic organisms experience both spatially and temporally variable exposures in the number of compounds, total concentrations, and estrogenicity. This variability was evident in fish collected from the three rivers as no clear upstream to downstream pattern of endocrine disruption endpoints emerged.

  13. Characterizing spatial and temporal patterns of cloud cover and fog inundation for the Northern Channel islands of California

    NASA Astrophysics Data System (ADS)

    Rastogi, Bharat

    The presence of low-lying stratocumulus clouds and fog has been known to modify biophysical and ecological properties in a variety of ecosystems in different climates. This is especially true for California's Channel Islands, where forests are frequently shaded by low-lying clouds or immersed in fog during warm and dry summer months. Previous studies suggest that clouds strongly modulate forest distributions as well as carbon and water budgets in these semi-arid environments by reducing solar insolation and raising relative humidity and thus reducing evapotranspiration, while also potentially supplying water directly to the landscape from fog-drip. While summertime fog and stratus cover in California's Channel Islands can ameliorate summer drought stress and enhance soil water budgets, they often have different spatial and temporal patterns. These differing patterns and the resulting shifts in relative ecological importance of fog and stratus are understudied. The overall objective of this study is to map spatial and temporal distributions of daytime cloud cover frequency for the California Channel Islands, and to predict probabilities of surface cloud (fog) contact and immersion for these islands. The results of this research are significant for water balance modeling, help explain vegetation patterns on the islands, and better identify locations where native vegetation restoration efforts are likely to be most successful.

  14. Complex temporal and spatial patterns in nonequilibrium processes. Progress report, December 1, 1987--November 30, 1992

    SciTech Connect

    Swinney, H.L.

    1992-10-01

    We have used dynamical systems methods to study and characterize bifurcations and pattern formation in a variety of nonequilibrium systems. In this paper we describe our work on dynamical systems, chemical oscillations and chaos, chemical spatial patterns, instabilities in fluid dynamics, electrodeposition clusters, the ballast resistor, and crack propagation.

  15. An investigation of acoustic beam patterns for the sonar localization problem using a beam based method.

    PubMed

    Guarato, Francesco; Windmill, James; Gachagan, Anthony; Harvey, Gerald

    2013-06-01

    Target localization can be accomplished through an ultrasonic sonar system equipped with an emitter and two receivers. Time of flight of the sonar echoes allows the calculation of the distance of the target. The orientation can be estimated from knowledge