Journal articles on the topic 'Cyclic temporal data'
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1
Phillips, Josh. "Cyclic tense: Discontinuous temporal reference in Djambarrpuyŋu." Semantics and Linguistic Theory 1 (December 29, 2022): 561. http://dx.doi.org/10.3765/salt.v1i0.5408.
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This paper presents a formal proposal for the semantics of Djambarrpuyŋu tense and temporal reference in Djambarrpuyŋu, a Yolŋu (Pama-Nyungan) variety spoken in northern Australia. On the basis of novel data, elicited in the field, it comprises the first formal treatment of “cyclic tense” phenomena, where formal devices encoding temporal remoteness are ostensibly “recycled” and posits a hypothesis about the diachronic development of cyclic tense systems.
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GAO, CHUNMING, CHANGHUI LI, GUANGHUA TAN, SONGRUI GUO, and KE XIAO. "ADAPTIVE SEGMENTATION APPROACH FOR HUMAN ACTION DATA." International Journal of Pattern Recognition and Artificial Intelligence 28, no. 08 (December 2014): 1455012. http://dx.doi.org/10.1142/s021800141455012x.
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Temporal segmentation of human motion data is an essential preparation process for action recognition. Due to the variability in the temporal scale of human action and the complexity of representing articulated motion, the research of it encounters many difficulties. Especially, when the number of behaviors contained in the motion sequences is unknown in advance, traditional algorithms cannot segment sequences successfully. In this paper, we extend previous works on change-points detection by probabilistic principle component analysis (PPCA). Based on it, an algorithm which is an extension of PCA and Maximum Mean Discrepancy between samples is proposed for estimating the cluster number. Finally, we optimize our approach and detect cyclic units of each action by aligned cluster analysis. We evaluate and compare the approach with the state-of-the-art methods on Synthetic data, Motion Capture Dataset and Kinect data. Experimental results demonstrate the effectiveness of our approach.
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De León-Lomelí, R., J. S. Murguía, I. Chouvarda, M. O. Méndez, E. González-Galván, and A. Alba. "Scaling analysis of heart beat fluctuations data and its relationship with cyclic alternating pattern data during sleep." International Journal of Modern Physics C 27, no. 07 (May 24, 2016): 1650071. http://dx.doi.org/10.1142/s0129183116500716.
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During sleep there exists a nonlinear dynamic phenomenon, which is called cyclic alternating pattern. This phenomenon is generated in the brain and is composed of a series of events of short duration known as A-phases. It has been shown that A-phases can be found in other physiological systems such as the cardiovascular. However, there is no evidence that shows the temporal influence of the A-phases with the cardiovascular system. For this purpose, we consider the scaling method known as detrended fluctuation analysis (DFA). The analysis was carried out in well sleepers and insomnia people, and the numerical results show an increment in the scaling parameter for the insomnia subjects compared with the normal ones. In addition, the results of the heart dynamics suggests a persistent behavior toward the [Formula: see text]-noise.
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Lai, Michael W., Nathan Chow, Antonio Checco, Balvir Kunar, David Redmond, Shahin Rafii, and Sina Y. Rabbany. "Systems Biology Analysis of Temporal Dynamics That Govern Endothelial Response to Cyclic Stretch." Biomolecules 12, no. 12 (December 8, 2022): 1837. http://dx.doi.org/10.3390/biom12121837.
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Endothelial cells in vivo are subjected to a wide array of mechanical stimuli, such as cyclic stretch. Notably, a 10% stretch is associated with an atheroprotective endothelial phenotype, while a 20% stretch is associated with an atheroprone endothelial phenotype. Here, a systems biology-based approach is used to present a comprehensive overview of the functional responses and molecular regulatory networks that characterize the transition from an atheroprotective to an atheroprone phenotype in response to cyclic stretch. Using primary human umbilical vein endothelial cells (HUVECs), we determined the role of the equibiaxial cyclic stretch in vitro, with changes to the radius of the magnitudes of 10% and 20%, which are representative of physiological and pathological strain, respectively. Following the transcriptome analysis of next-generation sequencing data, we identified four key endothelial responses to pathological cyclic stretch: cell cycle regulation, inflammatory response, fatty acid metabolism, and mTOR signaling, driven by a regulatory network of eight transcription factors. Our study highlights the dynamic regulation of several key stretch-sensitive endothelial functions relevant to the induction of an atheroprone versus an atheroprotective phenotype and lays the foundation for further investigation into the mechanisms governing vascular pathology. This study has significant implications for the development of treatment modalities for vascular disease.
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Chalyi, Serhii, Volodymyr Leshchynskyi, and Irina Leshchynska. "METHOD OF FORMING RECOMMENDATIONS USING TEMPORAL CONSTRAINTS IN A SITUATION OF CYCLIC COLD START OF THE RECOMMENDER SYSTEM." EUREKA: Physics and Engineering 4 (July 31, 2019): 34–40. http://dx.doi.org/10.21303/2461-4262.2019.00952.
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The problem of the formation of the recommended list of items in the situation of cyclic cold start of the recommendation system is considered. This problem occurs when building recommendations for occasional users. The interests of such consumers change significantly over time. These users are considered “cold” when accessing the recommendation system. A method for building recommendations in a cyclical cold start situation using temporal constraints is proposed. Temporal constraints are formed on the basis of the selection of repetitive pairs of actions for choosing the same objects at a given level of time granulation. Input data is represented by a set of user choice records. For each entry, a time stamp is indicated. The method includes the phases of the formation of temporal constraints, the addition of source data using these constraints, as well as the formation of recommendations using the collaborative filtering algorithm. The proposed method makes it possible, with the help of temporal constraints, to improve the accuracy of recommendations for “cold” users with periodic changes in their interests.
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Panzhin, Andrei, and Nataliia Panzhina. "Applying primary data from permanent stations for geodynamic zoning." Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal, no. 1 (February 17, 2021): 54–62. http://dx.doi.org/10.21440/0536-1028-2021-1-54-62.
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Introduction. The article focuses on present-day geodynamic motion in order to carry out geodynamic zoning of territories. Geodynamic monitoring may be both regional, for instance, of the Russian Federation, Ural region, geological rock mass, and it may also be local, i.e. covering a deposit and enclosing rock mass. Permanent stations of Global Navigation Satellite System (GNSS) have been used as a source of data for deformation monitoring. Methodology included the method of visualizing geodynamic motions according to the results of cyclic geodetic measurements which makes it possible to single out active geological structures, blocks, and tectonic faults on reasonable grounds. Results. It has been shown that it is advisable to use not modules of observation station displacement vector values but their velocities reduced to an annual cycle as a key source of information on geodynamic motion at large spatial-temporal bases. It has been indicated that an important characteristic of geodynamic motion vector field is divergence which characterizes the degree of convergence or divergence of a vector flux. Summary. Basic theses have been identified of the method of present-day geodynamic motions monitoring and visualization in the form of a vector field according to the results of cyclic geodetic measurements. Based on experimental data, it has been determined that the present-day geodynamic motion is vortical being the indicator of active tectonic faulting.
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de Mello Gallep, Cristiano, and Daniel Robert. "Are cyclic plant and animal behaviours driven by gravimetric mechanical forces?" Journal of Experimental Botany 73, no. 4 (November 2, 2021): 1093–103. http://dx.doi.org/10.1093/jxb/erab462.
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Abstract The celestial mechanics of the Sun, Moon, and Earth dominate the variations in gravitational force that all matter, live or inert, experiences on Earth. Expressed as gravimetric tides, these variations are pervasive and have forever been part of the physical ecology with which organisms evolved. Here, we first offer a brief review of previously proposed explanations that gravimetric tides constitute a tangible and potent force shaping the rhythmic activities of organisms. Through meta-analysis, we then interrogate data from three study cases and show the close association between the omnipresent gravimetric tides and cyclic activity. As exemplified by free-running cyclic locomotor activity in isopods, reproductive effort in coral, and modulation of growth in seedlings, biological rhythms coincide with temporal patterns of the local gravimetric tide. These data reveal that, in the presumed absence of rhythmic cues such as light and temperature, local gravimetric tide is sufficient to entrain cyclic behaviour. The present evidence thus questions the phenomenological significance of so-called free-run experiments.
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Roche, J. R., L. R. Turner, J. M. Lee, D. C. Edmeades, D. J. Donaghy, K. A. Macdonald, J. W. Penno, and D. P. Berry. "Weather, herbage quality and milk production in pastoral systems. 2. Temporal patterns and intra-relationships in herbage quality and mineral concentration parameters." Animal Production Science 49, no. 3 (2009): 200. http://dx.doi.org/10.1071/ea07308.
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Prevailing weather conditions influence herbage growth and quality, and therefore may have a substantial impact on animal production. Before investigating relationships between weather factors, herbage quality, and animal production, it is beneficial to first quantify temporal trends in herbage quality characteristics and mineral concentrations. The objective of the present study was to investigate the existence of temporal trends in herbage quality characteristics and mineral concentrations, and to quantify the intra-dependency among these variables. Weekly herbage quality and mineral concentration data from a research farm were collected from 1995 to 2001, inclusive. Fitted sinusoidal functions demonstrated cyclic temporal trends across herbage quality variables, but there was little cyclic temporal variation in the majority of herbage mineral concentration variables. The repeatability of herbage quality measurements was low to moderate (22% for ether extract to 54% for metabolisable energy). Linear relationships were observed within all herbage quality variables and herbage mineral concentration variables. Neutral detergent fibre and acid detergent fibre concentrations were strongly positively correlated with each other (r = 0.87), and negatively correlated with herbage digestibility (r = –0.64 and –0.74, respectively), water-soluble carbohydrate concentration (r = –0.52 and –0.68, respectively) and metabolisable energy content (r = –0.60 and –0.75, respectively). The absolute correlations among most herbage minerals were poor (r <0.30). However, magnesium concentration was positively correlated with calcium (r = 0.54), copper (r = 0.56), and manganese (r = 0.37) concentrations, and negatively correlated with zinc (r = –0.56) concentration. Further investigation is required into the relationships between temporal weather and herbage quality trends, and their impact on animal production.
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Liou, T.-M., and D. A. Santavicca. "Cycle Resolved LDV Measurements in a Motored IC Engine." Journal of Fluids Engineering 107, no. 2 (June 1, 1985): 232–40. http://dx.doi.org/10.1115/1.3242467.
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LDV measurements have been made in an IC engine motored at 1200 rpm. The data rates were sufficiently high to allow the bulk velocity to be characterized in individual cycles. The relative cyclic fluctuation of the bulk velocity was found to be as large as 200 percent. The turbulence intensity was calculated using both the velocity fluctuation with respect to the ensemble average velocity and the velocity fluctuation with respect to the cycle resolved bulk velocity. The former includes both the cyclic fluctuation of the bulk velocity and the turbulence, and therefore gave estimates of the ensemble averaged turbulence intensity which were from 50 to 100 percent greater than that obtained using the in-cycle fluctuation with respect to the bulk velocity. The relative cyclic fluctuation of the time averaged turbulence intensity, calculated over a 64-degree interval in each cycle, was found to be small, i.e., less than 20 percent. The high data rates also made it possible to determine the ensemble averaged temporal autocorrelation function from which the spectral energy distribution and the integral time scale were calculated.
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ROY, DEBORAH R. SAMANTA, and COLIN J. BARNSTABLE. "Developmental expression of intracellular targets of cGMP in rat visual cortex and alteration with dark rearing." Visual Neuroscience 18, no. 1 (January 2001): 109–18. http://dx.doi.org/10.1017/s0952523801181101.
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We describe the temporal pattern of mRNA expression of some of the molecular components of the NO/cGMP second messenger system in the developing rat visual cortex and the effect of dark rearing on their expression levels using semiquantitative RT-PCR. mRNA expression for these molecules was altered by dark rearing in one of three ways: (1) no change—rod, olfactory, and cone/testis CNG channels, nonselective cation channels gated by cyclic nucleotides and highly permeable to Ca2+; (2) decrease—cyclic nucleotide phosphodiesterases which regulate cyclic nucleotide levels, and soluble guanylyl cyclase, the key synthetic enzyme producing cGMP and potently activated by nitric oxide; and (3) increase—cGMP kinase I, a key enzyme activated by cGMP to phosphorylate a variety of intracellular proteins including cytoskeletal elements. These data suggest important and distinct roles for the cGMP system in both early and late developmental events in the rat visual cortex.
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Rivas-Casado, M., S. White, and P. Bellamy. "Guidelines for depth data collection in rivers when applying interpolation techniques (kriging) for river restoration." Hydrology and Earth System Sciences Discussions 4, no. 3 (May 16, 2007): 1069–94. http://dx.doi.org/10.5194/hessd-4-1069-2007.
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Abstract. River restoration appraisal requires the implementation of monitoring programmes that assess the river site before and after the restoration project. However, little work has yet been developed to design effective and efficient sampling strategies. Three main variables need to be considered when designing monitoring programmes: space, time and scale. The aim of this paper is to describe the methodology applied to analyse the variation of depth in space, scale and time so more comprehensive monitoring programmes can be developed. Geostatistical techniques were applied to study the spatial dimension (sampling strategy and density), spectral analysis was used to study the scale at which depth shows cyclic patterns, whilst descriptive statistics were used to assess the temporal variation. A brief set of guidelines have been summarised in the conclusion.
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Tenow, Olle. "Discovery of continental-scale travelling waves and lagged synchrony in geometrid moth outbreaks prompt a re-evaluation of mountain birch/geometrid studies." F1000Research 2 (September 6, 2013): 128. http://dx.doi.org/10.12688/f1000research.2-128.v2.
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The spatio-temporal dynamics of populations of two 9-10 year cyclic-outbreaking geometrids, Operophtera brumata and Epirrita autumnata in mountain birch forests in northern Fennoscandia, have been studied since the 1970´s by a Swedish-Norwegian research team and, during the last decade, by Norwegian and Finnish research teams. Some of the early results have been challenged by the Norwegian team. To examine the base for disagreements, five of the papers published by the Norwegian team (2004-2011) are reviewed. It is found that conclusions in these papers are questionable or data could not be interpreted fully because two decisive traits in the spatio-temporal behaviour of outbreaks of the two species were not considered.
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Ali, Ismail, Sandro Moiron, Martin Fleury, and Mohammed Ghanbari. "Congestion Resiliency for Data-Partitioned H.264/AVC Video Streaming Over IEEE 802.11e Wireless Networks." International Journal of Handheld Computing Research 3, no. 1 (January 2012): 55–73. http://dx.doi.org/10.4018/jhcr.2012010104.
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This paper examines the impact of data partitioning form on wireless network access control and proposes a selective dropping scheme based on dropping the partition carrying intra-coded macroblocks. Data partitioning is an error resiliency technique that allows unequal error protection for transmission over ‘lossy’ channels. Including a per-picture, cyclic intra-refresh macroblock line guards against temporal error propagation. The authors show that when congestion occurs, it is possible to gain up to 2 dB in video quality over assigning a stream to a single IEEE 802.11e access category. The scheme is consistently advantageous in indoor and outdoor wireless scenarios over other ways of assigning the partitioned data packets to different access categories. This counter-intuitive scheme for access control purposes reverses the priority usually given to partition-B data packets over that of partition-C.
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Testa, J. Ward, Gary Oehlert, David G. Ainley, John L. Bengtson, Donald B. Siniff, Richard M. Laws, and David Rounsevell. "Temporal Variability in Antarctic Marine Ecosystems: Periodic Fluctuations in the Phocid Seals." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 4 (April 1, 1991): 631–39. http://dx.doi.org/10.1139/f91-081.
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Three species of seals around Antarctica have shown quasi-cyclic patterns in some aspect of their biology: the age structure of crabeater seals (Lobodon carcinophagus) around the Antarctic Peninsula has shown strong cohorts separated by 4- to 5-yr intervals; juvenile leopard seals (Hydrurga leptonyx) have appeared in unusually large numbers at Macquarie Island, also at 4- to 5-yr intervals; and Weddell seals (Leptonychotes weddellii) in McMurdo Sound have undergone fluctuations in reproductive rate every 4–6 yr. Complex demodulation was used to compare patterns among these three data sets and with the Southern Oscillation Index (SOI). All of the seal data sets showed evidence of cyclical behavior when demodulated at a period of 5 yr. The Weddell seals were generally in phase with the SOI since the Weddell series began in 1970. The leopard seals and SOI were in phase in the 1960's, but thereafter the SOI series led the leopard seal series by about one quarter of a cycle. The crabeater series was more complicated, but similarities with the other data sets also were seen. If these tentative observations are confirmed, they point to large-scale oceanographic variation, possibly related to the El Niño – Southern Oscillation (ENSO), as an important mechanism in Antarctic marine ecosystems.
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Wessels, Deborah, Rebecca Brincks, Spencer Kuhl, Vesna Stepanovic, Karla J. Daniels, Gerald Weeks, Chinten J. Lim, et al. "RasC Plays a Role in Transduction of Temporal Gradient Information in the Cyclic-AMP Wave of Dictyostelium discoideum." Eukaryotic Cell 3, no. 3 (June 2004): 646–62. http://dx.doi.org/10.1128/ec.3.3.646-662.2004.
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ABSTRACT To define the role that RasC plays in motility and chemotaxis, the behavior of a rasC null mutant, rasC −, in buffer and in response to the individual spatial, temporal, and concentration components of a natural cyclic AMP (cAMP) wave was analyzed by using computer-assisted two-dimensional and three-dimensional motion analysis systems. These quantitative studies revealed that rasC − cells translocate at the same velocity and exhibit chemotaxis up spatial gradients of cAMP with the same efficiency as control cells. However, rasC − cells exhibit defects in maintaining anterior-posterior polarity along the substratum and a single anterior pseudopod when translocating in buffer in the absence of an attractant. rasC − cells also exhibit defects in their responses to both the increasing and decreasing temporal gradients of cAMP in the front and the back of a wave. These defects result in the inability of rasC − cells to exhibit chemotaxis in a natural wave of cAMP. The inability to respond normally to temporal gradients of cAMP results in defects in the organization of the cytoskeleton, most notably in the failure of both F actin and myosin II to exit the cortex in response to the decreasing temporal gradient of cAMP in the back of the wave. While the behavioral defect in the front of the wave is similar to that of the myoA −/myoF − myosin I double mutant, the behavioral and cytoskeletal defects in the back of the wave are similar to those of the S13A myosin II regulatory light-chain phosphorylation mutant. Expression array data support the premise that the behavioral defects exhibited by the rasC − mutant are the immediate result of the absence of RasC function.
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Sherratt, Jonathan A., and Matthew J. Smith. "Periodic travelling waves in cyclic populations: field studies and reaction–diffusion models." Journal of The Royal Society Interface 5, no. 22 (January 22, 2008): 483–505. http://dx.doi.org/10.1098/rsif.2007.1327.
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Periodic travelling waves have been reported in a number of recent spatio-temporal field studies of populations undergoing multi-year cycles. Mathematical modelling has a major role to play in understanding these results and informing future empirical studies. We review the relevant field data and summarize the statistical methods used to detect periodic waves. We then discuss the mathematical theory of periodic travelling waves in oscillatory reaction–diffusion equations. We describe the notion of a wave family, and various ecologically relevant scenarios in which periodic travelling waves occur. We also discuss wave stability, including recent computational developments. Although we focus on oscillatory reaction–diffusion equations, a brief discussion of other types of model in which periodic travelling waves have been demonstrated is also included. We end by proposing 10 research challenges in this area, five mathematical and five empirical.
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Evans, James A., Gideon Kunda, and Stephen R. Barley. "Beach Time, Bridge Time, and Billable Hours: The Temporal Structure of Technical Contracting." Administrative Science Quarterly 49, no. 1 (March 2004): 1–38. http://dx.doi.org/10.2307/4131454.
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This paper uses data from career histories of technical contractors to explore how they experience, interpret, and allocate their time and whether they take advantage of the temporal flexibility purportedly offered by contract work in the market. Technical contractors offer a unique opportunity for examining assumptions about organizations, work, and time because they are itinerant professionals who operate outside any single organizational context. We find that contractors do perceive themselves to have flexibility and that a few achieve a kind of flexibility unattained by most permanent employees doing similar work, but rather than take advantage of what they call “beach time” and “downtime,” the majority work long hours and rarely schedule their time flexibly. The contractors' use of time is constrained by the cyclic structure of employment, the centrality of reputation in markets for skill, the practice of billing by the hour, and the nature of technical work. Our research suggests that markets place more rather than fewer constraints on workers' time.
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Roche, J. R., L. R. Turner, J. M. Lee, D. C. Edmeades, D. J. Donaghy, K. A. Macdonald, J. W. Penno, and D. P. Berry. "Weather, herbage quality and milk production in pastoral systems. 1. Temporal patterns and intra-relationships in weather variables." Animal Production Science 49, no. 3 (2009): 192. http://dx.doi.org/10.1071/ea07307.
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Prevailing weather conditions are one factor that influences herbage growth and quality, and therefore may have a substantial impact on animal production. Before investigating relationships between weather factors, herbage growth and quality, and animal production, it is beneficial to first quantify temporal trends in weather variables. The objective of the present study was to investigate the existence of temporal weather trends in a predominantly dairy production region of New Zealand, and to quantify the level of intra-dependency among the weather variables measured. Daily weather data across the years 1995 to 2001 were merged. Fitted sinusoidal functions demonstrated cyclic temporal trends in weather throughout the year. Air and soil temperatures, radiation, and potential evapotranspiration were highly repeatable within fortnight. Repeatability of all other weather variables was low; for example repeatability of rainfall was ≤7%. Linear relationships were also observed among all weather variables. All air and soil temperature measurements were highly positively correlated with each other (r = 0.53–0.99), and with evaporation (r = 0.40–0.68) and potential evapotranspiration (r = 0.43–0.79), while maximum air temperature was positively correlated with radiation (r = 0.61). Further investigation is required to quantify the effect of temporal weather trends on herbage growth and quality, and subsequent animal production.
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Werner, Moritz, Roland Baar, Peter Haluska, and Ivo Sandor. "Bidirectional flow measurement based on the differential pressure method for surge analysis on a small centrifugal compressor." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 24 (September 7, 2016): 4450–60. http://dx.doi.org/10.1177/0954406216667406.
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To obtain a high temporal resolution of mass flow data, a flowmeter based on the differential pressure method has been developed. It is capable of detecting negative flow for investigations of dynamic effects in small centrifugal compressors used for turbocharging automotive internal combustion engines. Experiments were performed at a hot gas test bench focusing on the surge characteristics at different turbocharger speeds and the influence of volume modifications downstream of the compressor. Instantaneous operating points could be traced in the compressor map including the typical orbits at deep surge resulting from the cyclic character of the phenomenon.
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Edvartsen, Jone, Ville Maliniemi, Hilde Nesse Tyssøy, Timo Asikainen, and Spencer Hatch. "The Mansurov effect: Statistical significance and the role of autocorrelation." Journal of Space Weather and Space Climate 12 (2022): 11. http://dx.doi.org/10.1051/swsc/2022008.
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The Mansurov effect is related to the interplanetary magnetic field (IMF) and its ability to modulate the global electric circuit, which is further hypothesized to impact the polar troposphere through cloud generation processes. We investigate the connection between IMF By-component and polar surface pressure by using daily ERA5 reanalysis for geopotential height since 1980. Previous studies produce a 27-day cyclic response during solar cycle 23 which appears to be significant according to conventional statistical tests. However, we show here that when statistical tests appropriate for strongly autocorrelated variables are applied, there is a fairly high probability of obtaining the cyclic response and associated correlation merely by chance. Our results also show that data from three other solar cycles produce similar cyclic responses as during solar cycle 23, but with seemingly random offset in respect to the timing of the signal. By generating random normally distributed noise with different levels of temporal autocorrelation and using the real IMF By-time series as forcing, we show that the methods applied to support the Mansurov hypothesis up to now are highly susceptible to random chance as cyclic patterns always arise as artifacts of the methods. The potential non-stationary behavior of the Mansurov effect makes it difficult to achieve solid statistical significance on decadal time scales. We suggest more research on, e.g., seasonal dependence of the Mansurov effect to understand better potential IMF effects in the atmosphere.
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Van Lier Ribbink, J. A., M. G. Sarr, and M. Tanaka. "Neural isolation of the entire canine stomach in vivo: effects on motility." American Journal of Physiology-Gastrointestinal and Liver Physiology 257, no. 1 (July 1, 1989): G30—G40. http://dx.doi.org/10.1152/ajpgi.1989.257.1.g30.
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This study was designed to determine the effects of transection of all extrinsic and enteric neural continuity to the entire stomach on motility patterns of the stomach and small intestine. Five dogs were subjected to a model of orthotopic autotransplantation of the stomach to achieve an in vivo, "neurally isolated" stomach. Manometric catheters and serosal electrodes were implanted. A cyclic motor pattern occurred during fasting and was closely coordinated temporally with the migrating motor complex (MMC) in the small bowel. The period of the cyclic gastric motor activity did not differ from the period of the MMC in the small intestine [121 +/- 8 vs 124 +/- 10 (means +/- SE) min, P = 0.4], but the periods of both were greater than in control dogs (93 +/- 5 min, P less than 0.05). Tachygastria accounted for 36 +/- 13% of fasting myoelectric activity in the neurally isolated dogs and for less than 1% in control dogs. Plasma concentration of motilin was greatest during the phase III-like gastric motor activity; exogenous motilin induced premature phase III-like activity in the stomach and small intestine. Feeding abolished the cyclic motor activity in the stomach and decreased plasma motilin concentration. These data suggest that hormonal factors, and not extrinsic or intrinsic neural continuity to the stomach, may control both the initiation of a cyclic interdigestive gastric motor pattern and its temporal coordination with motor patterns in the small intestine.
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Guimarães, Vânia, Inês Sousa, and Miguel Velhote Correia. "Orientation-Invariant Spatio-Temporal Gait Analysis Using Foot-Worn Inertial Sensors." Sensors 21, no. 11 (June 7, 2021): 3940. http://dx.doi.org/10.3390/s21113940.
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Inertial sensors can potentially assist clinical decision making in gait-related disorders. Methods for objective spatio-temporal gait analysis usually assume the careful alignment of the sensors on the body, so that sensor data can be evaluated using the body coordinate system. Some studies infer sensor orientation by exploring the cyclic characteristics of walking. In addition to being unrealistic to assume that the sensor can be aligned perfectly with the body, the robustness of gait analysis with respect to differences in sensor orientation has not yet been investigated—potentially hindering use in clinical settings. To address this gap in the literature, we introduce an orientation-invariant gait analysis approach and propose a method to quantitatively assess robustness to changes in sensor orientation. We validate our results in a group of young adults, using an optical motion capture system as reference. Overall, good agreement between systems is achieved considering an extensive set of gait metrics. Gait speed is evaluated with a relative error of −3.1±9.2 cm/s, but precision improves when turning strides are excluded from the analysis, resulting in a relative error of −3.4±6.9 cm/s. We demonstrate the invariance of our approach by simulating rotations of the sensor on the foot.
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Greiner, Alexandra M., Sarah A. Biela, Hao Chen, Joachim P. Spatz, and Ralf Kemkemer. "Featured Article: Temporal responses of human endothelial and smooth muscle cells exposed to uniaxial cyclic tensile strain." Experimental Biology and Medicine 240, no. 10 (February 15, 2015): 1298–309. http://dx.doi.org/10.1177/1535370215570191.
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The physiology of vascular cells depends on stimulating mechanical forces caused by pulsatile flow. Thus, mechano-transduction processes and responses of primary human endothelial cells (ECs) and smooth muscle cells (SMCs) have been studied to reveal cell-type specific differences which may contribute to vascular tissue integrity. Here, we investigate the dynamic reorientation response of ECs and SMCs cultured on elastic membranes over a range of stretch frequencies from 0.01 to 1 Hz. ECs and SMCs show different cell shape adaptation responses (reorientation) dependent on the frequency. ECs reveal a specific threshold frequency (0.01 Hz) below which no responses is detectable while the threshold frequency for SMCs could not be determined and is speculated to be above 1 Hz. Interestingly, the reorganization of the actin cytoskeleton and focal adhesions system, as well as changes in the focal adhesion area, can be observed for both cell types and is dependent on the frequency. RhoA and Rac1 activities are increased for ECs but not for SMCs upon application of a uniaxial cyclic tensile strain. Analysis of membrane protrusions revealed that the spatial protrusion activity of ECs and SMCs is independent of the application of a uniaxial cyclic tensile strain of 1 Hz while the total number of protrusions is increased for ECs only. Our study indicates differences in the reorientation response and the reaction times of the two cell types in dependence of the stretching frequency, with matching data for actin cytoskeleton, focal adhesion realignment, RhoA/Rac1 activities, and membrane protrusion activity. These are promising results which may allow cell-type specific activation of vascular cells by frequency-selective mechanical stretching. This specific activation of different vascular cell types might be helpful in improving strategies in regenerative medicine.
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Miyazawa, Masatoshi, Anupama Venkataraman, Roel Snieder, and Michael A. Payne. "Analysis of microearthquake data at Cold Lake and its applications to reservoir monitoring." GEOPHYSICS 73, no. 3 (May 2008): O15—O21. http://dx.doi.org/10.1190/1.2901199.
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More than four months of continuously recorded micro-earthquake data acquired at Cold Lake, Canada, was analyzed using advanced algorithms for microearthquake location and subsurface tomography. Robust determination of the spatial, temporal, and magnitude distribution of seismicity is the first step toward understanding the relationship between the stress perturbations caused by the cyclic steam stimulation (CSS) process and seismicity. Acquisition geometry was constrained because the receivers were located in a single vertical borehole. Despite this constraint, we were successful in improving event locations by use of the double-difference method, which highlights several tight event clusters. The deep cluster at a depth of [Formula: see text], just above the oil reservoir, shows very high seismicity during the CSS processes. A second cluster is observed at shallower depths in the successive steam cycle. This suggests that repeated steaming causes the deformation to spread to shallower depths. The number of events, however, decreases in the second steam cycle. Even though some of the largest events occur below the Clearwater reservoir, we observed few events in the reservoir itself, indicating that the reservoir may be an aseismic region. The size and distribution of seismicity during the first cycle agrees with a Mohr's circle analysis using simple geomechanical modeling.
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Shi, Jiahao, Jie Yu, Jinkun Yang, Lingyu Xu, and Huan Xu. "Time Series Surface Temperature Prediction Based on Cyclic Evolutionary Network Model for Complex Sea Area." Future Internet 14, no. 3 (March 21, 2022): 96. http://dx.doi.org/10.3390/fi14030096.
Full textAbstract:
The prediction of marine elements has become increasingly important in the field of marine research. However, time series data in a complex environment vary significantly because they are composed of dynamic changes with multiple mechanisms, causes, and laws. For example, sea surface temperature (SST) can be influenced by ocean currents. Conventional models often focus on capturing the impact of historical data but ignore the spatio–temporal relationships in sea areas, and they cannot predict such widely varying data effectively. In this work, we propose a cyclic evolutionary network model (CENS), an error-driven network group, which is composed of multiple network node units. Different regions of data can be automatically matched to a suitable network node unit for prediction so that the model can cluster the data based on their characteristics and, therefore, be more practical. Experiments were performed on the Bohai Sea and the South China Sea. Firstly, we performed an ablation experiment to verify the effectiveness of the framework of the model. Secondly, we tested the model to predict sea surface temperature, and the results verified the accuracy of CENS. Lastly, there was a meaningful finding that the clustering results of the model in the South China Sea matched the actual characteristics of the continental shelf of the South China Sea, and the cluster had spatial continuity.
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Boccaccio, Anna, and Anna Menini. "Temporal Development of Cyclic Nucleotide-Gated and Ca2+-Activated Cl− Currents in Isolated Mouse Olfactory Sensory Neurons." Journal of Neurophysiology 98, no. 1 (July 2007): 153–60. http://dx.doi.org/10.1152/jn.00270.2007.
Full textAbstract:
A Ca2+-activated Cl− current constitutes a large part of the transduction current in olfactory sensory neurons. The binding of odorants to olfactory receptors in the cilia produces an increase in cAMP concentration; Ca2+ enters into the cilia through CNG channels and activates a Cl− current. In intact mouse olfactory sensory neurons little is known about the kinetics of the Ca2+-activated Cl− current. Here, we directly activated CNG channels by flash photolysis of caged cAMP or 8-Br-cAMP and measured the current response with the whole cell voltage-clamp technique in mouse neurons. We measured multiphasic currents in the rising phase of the response at −50 mV. The current rising phase became monophasic in the absence of extracellular Ca2+, at +50 mV, or when most of the intracellular Cl− was replaced by gluconate to shift the equilibrium potential for Cl− to −50 mV. These results show that the second phase of the current in mouse intact neurons is attributed to a Cl− current activated by Ca2+, similarly to previous results on isolated frog cilia. The percentage of the total saturating current carried by Cl− was estimated in two ways: 1) by measuring the maximum secondary current and 2) by blocking the Cl− channel with niflumic acid. We estimated that in the presence of 1 mM extracellular Ca2+ and in symmetrical Cl− concentrations the Cl− component can constitute up to 90% of the total current response. These data show how to unravel the CNG and Ca2+-activated Cl− component of the current rising phase.
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DIMITROV, B. D., and E. S. BABAYEV. "Cyclic variations in the dynamics of flu incidence in Azerbaijan, 1976–2000." Epidemiology and Infection 143, no. 1 (March 18, 2014): 13–22. http://dx.doi.org/10.1017/s095026881400048x.
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SUMMARYMulticomponent cyclicity in influenza (flu) incidence had been observed in various countries (e.g. periods T = 1, 2–3, 5–6, 8·0, 10·6–11·3, 13, 18–19 years) and its close similarity with cycles in natural environmental phenomena as meteorological factors and heliogeophysical activity (HGA) suggested. This report aimed at verifying previous results on cyclic patterns of flu incidence by exploring whether flu annual cyclicity (seasonality) and trans-year (13 to <24 months) and/or multiannual (long-term, ⩾24 months) cycles might be present. For this purpose, a relatively long monthly flu incidence dataset consisting of absolute numbers of new cases from the Grand Baku area, Azerbaijan, for the years 1976–2000 (300 months) was analysed. The exploration of underlying chronomes or, time structures, was done by linear and nonlinear parametric regression models, autocorrelation, spectral analysis and periodogram regression analysis. We analysed temporal dynamics and described multicomponent cyclicity, determining its statistical significance. The analysis, considering the flu data specifically stratified in three distinct intervals (1976–1990, 1991–1995, 1996–2000), and also combinations thereof, indicated that the main cyclic pattern was a seasonal one, with a period of T = 12 months. Further, a number of multiannual cycles with periods T in the ranges of 26–36, 62–85 or 113–162 months were observed, i.e. average periods of 2·5, 6·1 and 11·5 years, respectively. Indeed, most of these cycles correspond to similar cyclic parameters of HGA and further analyses are warranted to investigate such relationships. In conclusion, our study revealed the presence of multicomponent cyclic dynamics in influenza incidence by using relatively long time-series of monthly data. The specific cyclic patterns of flu incidence in Azerbaijan allows further, more specific modelling and correlations with environmental factors of similar cyclicity, e.g. HGA, to be explored. These results might contribute more widely to a better understanding of influenza dynamics and its aetiology as well as to the derivation of more precise forecasted estimates for planning and prevention purposes.
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De Meersman, K., J. M. Kendall, and M. van der Baan. "The 1998 Valhall microseismic data set: An integrated study of relocated sources, seismic multiplets, and S-wave splitting." GEOPHYSICS 74, no. 5 (September 2009): B183—B195. http://dx.doi.org/10.1190/1.3205028.
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We relocate 303 microseismic events recorded in 1998 by sensors in a single borehole in the North Sea Valhall oil field. A semiautomated array analysis method repicks the P- and S-wave arrival times and P-wave polarizations, which are needed to locate these events. The relocated sources are confined predominantly to a [Formula: see text]-thick zone just above the reservoir, and location uncertainties are half those of previous efforts. Multiplet analysis identifies 40 multiplet groups, which include 208 of the 303 events. The largest group contains 24 events, and five groups contain 10 or more events. Within each multiplet group, we further improve arrival-time picking through crosscorrelation, which enhances the relative accuracy of the relocated events and reveals that more than 99% of the seismic activity lies spatially in three distinct clusters. The spatial distribution of events and wave-form similarities reveal two faultlike structures that match well with north-northwest–south-southeast-trending fault planes interpreted from 3D surface seismic data. Most waveform differences between multiplet groups located on these faults can be attributed to S-wave phase content and polarity or P-to-S amplitude ratio. The range in P-to-S amplitude ratios observed on the faults is explained best in terms of varying source mechanisms. We also find a correlation between multiplet groups and temporal variations in seismic anisotropy, as revealed by S-wave splitting analysis. We explain these findings in the context of a cyclic recharge and dissipation of cap-rock stresses in response to production-driven compaction of the underlying oil reservoir. The cyclic nature of this mechanism drives the short-term variations in seismic anisotropy and the reactivation of microseismic source mechanisms over time.
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Matano, Fabio, Mauro Caccavale, Giuseppe Esposito, Alberto Fortelli, Germana Scepi, Maria Spano, and Marco Sacchi. "Integrated dataset of deformation measurements in fractured volcanic tuff and meteorological data (Coroglio coastal cliff, Naples, Italy)." Earth System Science Data 12, no. 1 (February 13, 2020): 321–44. http://dx.doi.org/10.5194/essd-12-321-2020.
Full textAbstract:
Abstract. Along the coastline of the Phlegraean Fields volcanic district, near Naples (Italy), severe retreat processes affect a large part of the coastal cliffs, mainly made of fractured volcanic tuff and pyroclastic deposits. Progressive fracturing and deformation of rocks can lead to hazardous sudden slope failures on coastal cliffs. Among the triggering mechanisms, the most relevant are related to meteorological factors, such as precipitation and thermal expansion due to solar heating of rock surfaces. In this paper, we present a database of measurement time series taken over a period of ∼4 years (December 2014–October 2018) for the deformations of selected tuff blocks in the Coroglio coastal cliff. The monitoring system is implemented on five unstable tuff blocks and is formed by nine crackmeters and two tiltmeters equipped with internal thermometers. The system is coupled with a total weather station, measuring rain, temperature, wind and atmospheric pressure and operating from January 2014 up to December 2018. Measurement frequencies of 10 and 30 min have been set for meteorological and deformation sensors respectively. The aim of the measurements is to assess the magnitude and temporal pattern of rock block deformations (fracture opening and block movements) before block failure and their correlation with selected meteorological parameters. The results of a multivariate statistical analysis of the measured time series suggest a close correlation between temperature and deformation trends. The recognized cyclic, sinusoidal changes in the width (opening–closing) of fractures and tuff block rotations are ostensibly linked to multiscale (i.e., daily, seasonal and annual) temperature variations. Some trends of cumulative multi-temporal changes have also been recognized. The full databases are freely available online at: https://doi.org/10.1594/PANGAEA.896000 (Matano et al., 2018) and https://doi.org/10.1594/PANGAEA.899562 (Fortelli et al., 2019).
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Opere, E., S. G. Juma, and B. Sitienei. "Trends in monthly rainfall and temperature in Rachuonyo North Sub-County, Kenya." Ethiopian Journal of Environmental Studies and Management 9, no. 6 (November 30, 2016): 738–47. http://dx.doi.org/10.4314/ejesm.v9i6.6.
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We analyse Climate Research Unit (CRU) Precipitation (1961-2014) and Temperature (1985-2014) data trends over Rachuonyo North Sub County at 50×50 km resolution. Time series and correlation analysis of the data was carried out. Temporal characteristics of temperature and Rainfall were determined. One sample t-tailed test of hypothesis was carried out. An increasing trend in temperature is observed over the years while a decreasing trend in precipitation is observed by the year 2014. The trends exhibited a cyclic and Seasonal pattern with Increasing Variability. Descriptive statistics revealed Rainfall and Temperature Means of 119.8 mm and 19.6 °C respectively. The results of one tailed t-test revealed that the change in Rainfall and temperature patterns over the area of study were not statistically significant.Keywords: Climate Change, Temperature, Rainfall Trend, Rachuonyo, Kenya
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Veitch, JA, and C. Martinsons. "Detection of the stroboscopic effect by young adults varying in sensitivity." Lighting Research & Technology 52, no. 6 (February 12, 2020): 790–810. http://dx.doi.org/10.1177/1477153519898718.
Full textAbstract:
The advent of LED lighting has renewed concern about the possible visual, neurobiological, and performance and cognition effects of cyclic variations in lighting system luminous flux (temporal light modulation). The stroboscopic visibility measure (SVM) characterises the temporal light modulation signal to predict the visibility of the stroboscopic effect, one of the visual perception effects of temporal light modulation. A SVM of 1 means that the average person would detect the phenomenon 50% of the time. There is little published data describing the population sensitivity to the stroboscopic effect in relation to the SVM, and none focusing on people subject to visual stress. This experiment, conducted in parallel in Canada and France, examined stroboscopic detection for horizontal and vertical moving targets when viewed under commercially available lamps varying in SVM conditions (SVM: ∼0; ∼0.4; ∼0.9; ∼1.4; ∼3.0). As expected, stroboscopic detection scores increased with increasing SVM. For the horizontal task, average scores were lower than the expected 4/8 at ∼0.90, but increased non-linearly with higher SVMs. Stroboscopic detection scores did not differ between people low and high in pattern glare sensitivity, but people in the high-pattern glare sensitivity group reported greater annoyance in the SVM ∼1.4 and ∼3.0 conditions.
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Blanco, Juan, Ángeles Moroño, Fabiola Arévalo, Jorge Correa, Covadonga Salgado, Araceli E. Rossignoli, and J. Pablo Lamas. "Twenty-Five Years of Domoic Acid Monitoring in Galicia (NW Spain): Spatial, Temporal and Interspecific Variations." Toxins 13, no. 11 (October 25, 2021): 756. http://dx.doi.org/10.3390/toxins13110756.
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Prevalence, impact on shellfish resources and interspecific, spatial, and temporal variabilities of domoic acid (DA) in bivalves from Galicia (NW Spain) have been studied based on more than 25 years of monitoring data. The maximum prevalence (samples in which DA was detected) (100%) and incidence (samples with DA levels above the regulatory limit) (97.4%) were recorded in Pecten maximus, and the minimum ones in Mytilus galloprovincialis (12.6 and 1.1%, respectively). The maximum DA concentrations were 663.9 mg kg−1 in P. maximus and 316 mg kg−1 in Venerupis corrugata. After excluding scallop P. maximus data, DA was found (prevalence) in 13.3% of bivalve samples, with 1.3% being over the regulatory limit. In general, the prevalence of this toxin decreased towards the North but not the magnitude of its episodes. The seasonal distribution was characterized by two maxima, in spring and autumn, with the later decreasing in intensity towards the north. DA levels decreased slightly over the studied period, although this decreasing trend was not linear. A cyclic pattern was observed in the interannual variability, with cycles of 4 and 11 years. Intoxication and detoxification rates were slower than those expected from laboratory experiments, suggesting the supply of DA during these phases plays an important role.
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Cho, Eunsaem, and Chulsang Yoo. "Analysis of the Spatiotemporal Behavior of Precipitation in South Korea Based on EOF and CSEOF Analyses." Journal of the Korean Society of Hazard Mitigation 20, no. 4 (August 31, 2020): 21–32. http://dx.doi.org/10.9798/kosham.2020.20.4.21.
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In this study, EOF analysis and CSEOF analysis were applied to major ASOS precipitation data in Korea to evaluate the spatiotemporal variability of precipitation in Korea. It was concluded that both EOF and CSEOF analyses are appropriate for identifying the spatiotemporal characteristics of precipitation in Korea. In particular, the CSEOF analysis method was able to interpret the temporal, cyclic behavior of precipitation data in detail. Both EOF and CSEOF showed that the first component explained the variance of most of the raw data. From the first EOF to the third EOF, the authors identified the average precipitation characteristics in Korea, precipitation characteristics according to latitude, and the phenomenon estimated by the mountain effect. The first CSEOF was characterized by precipitation in summer and winter in Korea, the second CSEOF was characterized by latitude and local precipitation, and the third CSEOF was characterized by varied and complex variation in precipitation.
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Nanavati, Nirali R., Neeraj Sen, and Devesh C. Jinwala. "Analysis and Evaluation of Novel Privacy Preserving Techniques for Collaborative Temporal Association Rule Mining Using Secret Sharing." International Journal of Distributed Systems and Technologies 5, no. 3 (July 2014): 58–76. http://dx.doi.org/10.4018/ijdst.2014070103.
Full textAbstract:
With digital data being abundant in today's world, competing organizations desire to gain insights about the market, without putting the privacy of their confidential data at risk. This paper provides a new dimension to the problem of Privacy Preserving Distributed Association Rule Mining (PPDARM) by extending it to a distributed temporal setup. It proposes extensions of public key based and non-public key based additively homomorphic techniques, based on efficient private matching and Shamir's secret sharing, to privately decipher these global cycles in cyclic association rules. Along with the theoretical analysis, it presents experimental results to substantiate it. This paper observes that the Secret Sharing scheme is more efficient than the one based on Paillier homomorphic encryption. However, it observes a considerable increase in the overhead associated with the Shamir's secret sharing scheme, as a result of the increase in the number of parties. To reduce this overhead, it extends the secret sharing scheme without mediators to a novel model with a Fully Trusted and a Semi Trusted Third Party. The experimental results establish this functioning for global cycle detections in a temporal setup as a case study. The novel constructions proposed can also be applied to other scenarios that want to undertake Secure Multiparty Computation (SMC) for PPDARM.
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Li, Yunyue Elita, Enhedelihai Alex Nilot, Yumin Zhao, and Gang Fang. "Quantifying Urban Activities Using Nodal Seismometers in a Heterogeneous Urban Space." Sensors 23, no. 3 (January 24, 2023): 1322. http://dx.doi.org/10.3390/s23031322.
Full textAbstract:
Earth’s surface is constantly vibrating due to natural processes inside and human activities on the surface of the Earth. These vibrations form the ambient seismic fields that are measured by sensitive seismometers. Compared with natural processes, anthropogenic vibrations dominate the seismic measurements at higher frequency bands, demonstrate clear temporal and cyclic variability, and are more heterogeneous in space. Consequently, urban ambient seismic fields are a rich information source for human activity monitoring. Improving from the conventional energy-based seismic spectral analysis, we utilize advanced signal processing techniques to extract the occurrence of specific urban activities, including motor vehicle counts and runner activities, from the high-frequency ambient seismic noise. We compare the seismic energy in different frequency bands with the extracted activity intensity at different locations within a one-kilometer radius and highlight the high-resolution information in the seismic data. Our results demonstrate the intense heterogeneity in a highly developed urban space. Different sectors of urban society serve different functions and respond differently when urban life is severely disturbed by the impact of the COVID-19 pandemic in 2020. The anonymity of seismic data enabled an unprecedented spatial and temporal resolution, which potentially could be utilized by government regulators and policymakers for dynamic monitoring and urban management.
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Xu, Chunrui, Henry Hollis, Michelle Dai, Xiangyu Yao, Layne T. Watson, Yang Cao, and Minghan Chen. "Modeling the temporal dynamics of master regulators and CtrA proteolysis in Caulobacter crescentus cell cycle." PLOS Computational Biology 18, no. 1 (January 28, 2022): e1009847. http://dx.doi.org/10.1371/journal.pcbi.1009847.
Full textAbstract:
The cell cycle of Caulobacter crescentus involves the polar morphogenesis and an asymmetric cell division driven by precise interactions and regulations of proteins, which makes Caulobacter an ideal model organism for investigating bacterial cell development and differentiation. The abundance of molecular data accumulated on Caulobacter motivates system biologists to analyze the complex regulatory network of cell cycle via quantitative modeling. In this paper, We propose a comprehensive model to accurately characterize the underlying mechanisms of cell cycle regulation based on the study of: a) chromosome replication and methylation; b) interactive pathways of five master regulatory proteins including DnaA, GcrA, CcrM, CtrA, and SciP, as well as novel consideration of their corresponding mRNAs; c) cell cycle-dependent proteolysis of CtrA through hierarchical protease complexes. The temporal dynamics of our simulation results are able to closely replicate an extensive set of experimental observations and capture the main phenotype of seven mutant strains of Caulobacter crescentus. Collectively, the proposed model can be used to predict phenotypes of other mutant cases, especially for nonviable strains which are hard to cultivate and observe. Moreover, the module of cyclic proteolysis is an efficient tool to study the metabolism of proteins with similar mechanisms.
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Muraközy, Judit, and András Ludmány. "Correlations of magnetic features and the torsional pattern." Proceedings of the International Astronomical Union 6, S273 (August 2010): 394–98. http://dx.doi.org/10.1017/s1743921311015626.
Full textAbstract:
AbstractThe striking similarity between the cyclic equatorward migration of the torsional oscillation belts and the sunspot activity latitudes inspired several attempts to seek an explanation of the torsional phenomenon in terms of interactions between flux ropes and plasma motions. The aim of the present work is to examine the spatial and temporal coincidences of the torsional waves and the emergence of sunspot magnetic fields. The locations of the shearing latitudes have been compared with the distributions of certain sunspot parameters by using sunspot data of more than two cycles. The bulges of the sunspot number and area distributions tend to be located within the ‘forward’ belts close to their poleward shearing borders. A possible geometry of the magnetic and velocity field interacion is proposed.
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Anders, Royce, Anaïs Llorens, Anne-Sophie Dubarry, Agnès Trébuchon, Catherine Liégeois-Chauvel, and F. Xavier Alario. "Cortical Dynamics of Semantic Priming and Interference during Word Production: An Intracerebral Study." Journal of Cognitive Neuroscience 31, no. 7 (July 2019): 978–1001. http://dx.doi.org/10.1162/jocn_a_01406.
Full textAbstract:
Language production requires that semantic representations are mapped to lexical representations on the basis of the ongoing context to select the appropriate words. This mapping is thought to generate two opposing phenomena, “semantic priming,” where multiple word candidates are activated, and “interference,” where these word activities are differentiated to make a goal-relevant selection. In previous neuroimaging and neurophysiological research, priming and interference have been associated to activity in regions of a left frontotemporal network. Most of such studies relied on recordings that either have high temporal or high spatial resolution, but not both. Here, we employed intracerebral EEG techniques to explore with both high resolutions, the neural activity associated with these phenomena. The data came from nine epileptic patients who were stereotactically implanted for presurgical diagnostics. They performed a cyclic picture-naming task contrasting semantically homogeneous and heterogeneous contexts. Of the 84 brain regions sampled, 39 showed task-evoked activity that was significant and consistent across two patients or more. In nine of these regions, activity was significantly modulated by the semantic manipulation. It was reduced for semantically homogeneous contexts (i.e., priming) in eight of these regions, located in the temporal ventral pathway as well as frontal areas. Conversely, it was increased only in the pre-SMA, notably at an early poststimulus temporal window (200–300 msec) and a preresponse temporal window (700–800 msec). These temporal effects respectively suggest the pre-SMA's role in initial conflict detection (e.g., increased response caution) and in preresponse control. Such roles of the pre-SMA are traditional from a history of neural evidence in simple perceptual tasks, yet are also consistent with recent cognitive lexicosemantic theories that highlight top–down processes in language production. Finally, although no significant semantic modulation was found in the ACC, future intracerebral EEG work should continue to inspect ACC with the pre-SMA.
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Suominen, Tapio, Jan Westerholm, Risto Kalliola, and Jenni Attila. "Partition of Marine Environment Dynamics According to Remote Sensing Reflectance and Relations of Dynamics to Physical Factors." Remote Sensing 13, no. 11 (May 27, 2021): 2104. http://dx.doi.org/10.3390/rs13112104.
Full textAbstract:
Seawaters exhibit various types of cyclic and trend-like temporal alterations in their biological, physical, and chemical processes. Surface water dynamics may vary, for instance, when the timings, durations, or amplitudes of seasonal developments of water properties alter between years and locations. We introduce a workflow using remote sensing to identify surface waters undergoing similar dynamics. The method, called ocean surface dynamics partitioning, classifies pixels based on their temporal change patterns instead of their properties at successive time snapshots. We apply an efficient parallel computing method to calculate Dynamic Time Warping (DTW) time series distances of large datasets of Earth Observation MERIS-instrument reflectance data Rrs(510 nm) and Rrs(620 nm), and produce a matrix of time series distances between 12,252 locations/time series in the Baltic Sea, for both wavelengths. We define cluster prototypes by hierarchical clustering of distance matrices and use them as initial prototypes for an iterative process of partitional clustering in order to identify areas that have similar reflectance dynamics. Lastly, we compute distances from the time series of the reflectance data to selected physical factors (wind, precipitation, and changes in sea surface temperature) obtained from Copernicus data archives. The workflow is reproducible and capable of managing large datasets in reasonable computation times and identifying areas of distinctive dynamics. The results show spatially coherent and logical areas without a priori information about the locations of the satellite image time series. The alignments of the reflectance time series vs. the observational time series of the physical environment clarify the causalities behind the cluster formation. We conclude that following the changes in an aquatic realm by biogeochemical observations at certain temporal intervals alone is not sufficient to identify environmental shifts. We foresee that the changes in dynamics are a sensitive measure of environmental threats and therefore they will be important to follow in the future.
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Panzhin, Andrey. "Identification of geodynamic movements based on the results of geodetic monitoring measurements." E3S Web of Conferences 192 (2020): 04001. http://dx.doi.org/10.1051/e3sconf/202019204001.
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The methodology and results of an experimental study of modern geodynamic movements using the data from geodetic deformation monitoring are presented. The related issues of modeling natural, anthropogenic, and ecological systems are considered. A technique for visualizing geodynamic movements based on the results of cyclic geodetic measurements, which allows to reasonably identify active geological structures, blocks, tectonic faults, is presented. It is shown that as a key source of information on geodynamic movements over large spatio-temporal intervals, it is advisable to use not the absolute values of the vectors of displacement of observation points, but their velocities, normalized to the annual cycle. It is indicated that an important characteristic of the vector field of geodynamic movements is divergence, which characterizes the degree of convergence or divergence of the vector flow.
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Ronold, K. O., and S. Haver. "Foundation Safety of Gravity-Based Systems During Severe Storms." Journal of Offshore Mechanics and Arctic Engineering 114, no. 2 (May 1, 1992): 104–13. http://dx.doi.org/10.1115/1.2919957.
Full textAbstract:
The temporal evolutions of the most important sea state characteristics during storms are presented together with the corresponding uncertainties. Storm data from the Northern North Sea are used for this purpose. The influence of the uncertainties associated with an extreme storm on the foundation safety is demonstrated for a gravity-based structural system founded on a clay. The stability is analyzed with respect to failure in large cyclic displacements accumulated during the storm. The failure probability is estimated by a first-order reliability method and the most important variables concerning their contribution to the failure probability are indicated. In most practical foundation safety investigations, an idealized deterministic storm profile is adopted. The adequacy of this profile is considered by calibrating a “load factor” to be used in connection with the idealized profile.
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Gorfman, Semën, Hyeokmin Choe, Michael Ziolkowski, Stefan Heidbrink, Marco Vogt, and Ullrich Pietsch. "Atomic, strain and domain dynamics in ferroelectrics under cyclic electric field." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C42. http://dx.doi.org/10.1107/s2053273314099574.
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Structural dynamics is a subject of a recent interest in solid state physics and a challenge for modern X-ray crystallography. Time-dependent response of solids to an external perturbation on atomic, mesoscopic and macroscopic length scales is the key to understanding many physical properties. We present the data-acquisition system (Gorfman et al., 2013) (DAQ) for X-ray diffraction study of repetitive micro- or millisecond dynamics in a broad range of materials (Gorfman, 2014) under cyclic perturbation. The DAQ operates on the principle of a multichannel analyser: it collects pulses from a single-photon-counting detector and resorts them between 10000 channels. Each channel corresponds to a certain time delay relative to the beginning of a latest perturbation cycle. The width of a channel (temporal resolution of the experiment) can be as small as 10 ns. We investigated atomic, strain and domain dynamics in SrxBa1-xNb2O6 single crystals: SBN50 (x=0.5, uniaxial ferroelectric) and SBN61(x=0.61, uniaxial relaxor ferroelectric). The experiments questioned the reason for large piezoelectric effect in uniaxial ferroelectrics where 1800(inversion) domains are present, while non-1800domains are absent. We applied triangular electric field (Figure 1) of variable frequencies and variable strengths. The time and electric field dependence of a set of Bragg rocking curves were followed: intensities, positions and peak widths were analysed giving access to atomic, strain and domain dynamics under external electric field. Figure 1. Left: contour plot of a -5 9 7 Bragg rocking curves from SBN50 single crystal collected under dynamically applied sub-coercive electric field. Right: dynamics of the peak position as a function of applied electric field, showing non-linear and hysteretic behaviour.
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Papa, Paula de Carvalho, Liza Margareth Medeiros de Carvalho Sousa, Renata dos Santos Silva, Luciana Alves de Fátima, Vanessa Uemura da Fonseca, Vanessa Coutinho do Amaral, Bernd Hoffmann, Ana Bárbara Alves-Wagner, Ubiratan Fabres Machado, and Mariusz Pawel Kowalewski. "Glucose transporter 1 expression accompanies hypoxia sensing in the cyclic canine corpus luteum." REPRODUCTION 147, no. 1 (January 2014): 81–89. http://dx.doi.org/10.1530/rep-13-0398.
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The canine corpus luteum (CL) functions as a source of progesterone (P4) and 17β-oestradiol (E2); however, the transport of energy substrates to maintain its high hormonal output has not yet been characterised. This study involved the localisation and temporal distribution of the facilitative glucose transporter 1 and the quantification of the corresponding protein (GLUT1) and gene (SLC2A1) expression. Some GLUT1/SLC2A1 regulatory proteins, such as hypoxia-inducible factor 1α (HIF1A) and fibroblast growth factor 2 (FGF2); mRNAs, such as HIF1A, FGF2 and vascular endothelial growth factor A (VEGFA); and VEGFA receptors 1 and 2 (FLT1 and KDR) were also analysed from days 10 to 70 after ovulation. Additionally, plasma P4 and E2 levels were assessed via chemiluminescence. Moreover, the canine KDR sequence has been cloned, thereby enabling subsequent semi-quantitative PCR analysis. Our results demonstrate time-dependent variations in the expression profile of SLC2A1 during dioestrus, which were accompanied by highly correlated changes (0.84<r<0.98; P<0.03) in the gene expression of HIF1A, VEGF and FLT1 as well as in P4 plasma concentrations. FGF2 mRNA correlated with E2 plasma concentrations (r=0.61; P=0.01). Our data reveal that the glucose transporter is regulated throughout the CL lifespan and suggest that CL depends on the sensing of hypoxia and the status of luteal vascularisation. Moreover, time-dependent expression of GLUT1/SLC2A1 may lie underneath increased metabolic and energetic requirements for sustaining P4 production.
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Husted, Russell F., Gerard P. Clancy, Abigail Adams-Brotherton, and John B. Stokes. "Inhibition of Na transport by 2-chloroadenosine: dissociation from production of cyclic nucleotides." Canadian Journal of Physiology and Pharmacology 68, no. 10 (October 1, 1990): 1357–62. http://dx.doi.org/10.1139/y90-205.
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The adenosine analogue 2-chloroadenosine (2-CA) is often used to determine the biologic effects of adenosine because 2-CA is less susceptible to degradation than adenosine. We studied the effects of 2-CA on primary cultures of rat inner medullary collecting ducts because there is good evidence that adenosine can influence cell function through its effects on second messengers. 2-CA inhibited Na+ transport across the apical membrane and increased cAMP content of the cells. The major adenosine receptors in these cells appear to be the stimulatory (A2) type. Stimulation of cAMP by 2-CA was more potent when applied to the apical membrane than to the basolateral membrane, an effect opposite to that of vasopressin. These results imply that adenosine receptors are more numerous or more effective on the apical membrane than on the basolateral membrane. Inhibition of Na+ transport was probably not mediated by an adenosine receptor as evidenced by (i) a lack of effect of adenosine and other adenosine analogues on Na+ transport; (ii) a lack of effect of nonmetabolizable cyclic nucleotides on Na+ transport; and (iii) a clear discrepancy in the temporal course of 2-CA effects on a second messenger system (cAMP) and 2-CA inhibition of Na+ transport. Dipyridimole, an inhibitor of adenosine transport, also reduced Na+ transport. Taken together, the data suggest that 2-CA inhibits Na+ transport by interfering with adenosine transport or metabolism.Key words: cAMP, cGMP, 2-chloroadenosine, vasopressin, Na+ transport, dipyridimole, adenosine metabolism.
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Maloof, Adam C., Daniel P. Schrag, James L. Crowley, and Samuel A. Bowring. "An expanded record of Early Cambrian carbon cycling from the Anti-Atlas Margin, Morocco." Canadian Journal of Earth Sciences 42, no. 12 (December 1, 2005): 2195–216. http://dx.doi.org/10.1139/e05-062.
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We present a δ13C record from the Anti-Atlas mountains of Morocco and place it in the context of a detailed regional tectonostratigraphy. We place the litho- and chemostratigraphic record in a temporal framework using precision UPb zircon geochronology of ashes interbedded with the same carbonate units that provide δ13C data. The variations in δ13C of carbonate occur on a wide range of time scales, suggesting that different mechanisms are involved, including non-steady state release of isotopically depleted carbon reservoirs on short (<100 000 years) time scales and changes in nutrient recycling and organic carbon burial on longer (≥1 Ma) time scales. Through a correlation with more fossiliferous, albeit condensed, sections in Siberia, we examine the pattern of cyclic δ13C variation in the context of the reappearance and diversification of skeletonized metazoa during the Early Cambrian.
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Wang, Jingkui, Laura Symul, Jake Yeung, Cédric Gobet, Jonathan Sobel, Sarah Lück, Pål O. Westermark, Nacho Molina, and Felix Naef. "Circadian clock-dependent and -independent posttranscriptional regulation underlies temporal mRNA accumulation in mouse liver." Proceedings of the National Academy of Sciences 115, no. 8 (February 5, 2018): E1916—E1925. http://dx.doi.org/10.1073/pnas.1715225115.
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The mammalian circadian clock coordinates physiology with environmental cycles through the regulation of daily oscillations of gene expression. Thousands of transcripts exhibit rhythmic accumulations across mouse tissues, as determined by the balance of their synthesis and degradation. While diurnally rhythmic transcription regulation is well studied and often thought to be the main factor generating rhythmic mRNA accumulation, the extent of rhythmic posttranscriptional regulation is debated, and the kinetic parameters (e.g., half-lives), as well as the underlying regulators (e.g., mRNA-binding proteins) are relatively unexplored. Here, we developed a quantitative model for cyclic accumulations of pre-mRNA and mRNA from total RNA-seq data, and applied it to mouse liver. This allowed us to identify that about 20% of mRNA rhythms were driven by rhythmic mRNA degradation, and another 15% of mRNAs regulated by both rhythmic transcription and mRNA degradation. The method could also estimate mRNA half-lives and processing times in intact mouse liver. We then showed that, depending on mRNA half-life, rhythmic mRNA degradation can either amplify or tune phases of mRNA rhythms. By comparing mRNA rhythms in wild-type and Bmal1−/− animals, we found that the rhythmic degradation of many transcripts did not depend on a functional BMAL1. Interestingly clock-dependent and -independent degradation rhythms peaked at distinct times of day. We further predicted mRNA-binding proteins (mRBPs) that were implicated in the posttranscriptional regulation of mRNAs, either through stabilizing or destabilizing activities. Together, our results demonstrate how posttranscriptional regulation temporally shapes rhythmic mRNA accumulation in mouse liver.
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Karklinsky, Matan, and Tamar Flash. "Timing of continuous motor imagery: the two-thirds power law originates in trajectory planning." Journal of Neurophysiology 113, no. 7 (April 2015): 2490–99. http://dx.doi.org/10.1152/jn.00421.2014.
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The two-thirds power law, v = γκ−1/3, expresses a robust local relationship between the geometrical and temporal aspects of human movement, represented by curvature κ and speed v, with a piecewise constant γ. This law is equivalent to moving at a constant equi-affine speed and thus constitutes an important example of motor invariance. Whether this kinematic regularity reflects central planning or peripheral biomechanical effects has been strongly debated. Motor imagery, i.e., forming mental images of a motor action, allows unique access to the temporal structure of motor planning. Earlier studies have shown that imagined discrete movements obey Fitts's law and their durations are well correlated with those of actual movements. Hence, it is natural to examine whether the temporal properties of continuous imagined movements comply with the two-thirds power law. A novel experimental paradigm for recording sparse imagery data from a continuous cyclic tracing task was developed. Using the likelihood ratio test, we concluded that for most subjects the distributions of the marked positions describing the imagined trajectory were significantly better explained by the two-thirds power law than by a constant Euclidean speed or by two other power law models. With nonlinear regression, the β parameter values in a generalized power law, v = γκ−β, were inferred from the marked position records. This resulted in highly variable yet mostly positive β values. Our results imply that imagined trajectories do follow the two-thirds power law. Our findings therefore support the conclusion that the coupling between velocity and curvature originates in centrally represented motion planning.
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Meyer, Frédéric, Magne Lund-Hansen, Trine M. Seeberg, Jan Kocbach, Øyvind Sandbakk, and Andreas Austeng. "Inner-Cycle Phases Can Be Estimated from a Single Inertial Sensor by Long Short-Term Memory Neural Network in Roller-Ski Skating." Sensors 22, no. 23 (November 28, 2022): 9267. http://dx.doi.org/10.3390/s22239267.
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Objective: The aim of this study was to provide a new machine learning method to determine temporal events and inner-cycle parameters (e.g., cycle, pole and ski contact and swing time) in cross-country roller-ski skating on the field, using a single inertial measurement unit (IMU). Methods: The developed method is based on long short-term memory neural networks to detect the initial and final contact of the poles and skis with the ground during the cyclic movements. Eleven athletes skied four laps of 2.5 km at a low and high intensity using skis with two different rolling coefficients. They were equipped with IMUs attached to the upper back, lower back and to the sternum. Data from force insoles and force poles were used as the reference system. Results: The IMU placed on the upper back provided the best results, as the LSTM network was able to determine the temporal events with a mean error ranging from −1 to 11 ms and had a standard deviation (SD) of the error between 64 and 70 ms. The corresponding inner-cycle parameters were calculated with a mean error ranging from −11 to 12 ms and an SD between 66 and 74 ms. The method detected 95% of the events for the poles and 87% of the events for the skis. Conclusion: The proposed LSTM method provides a promising tool for assessing temporal events and inner-cycle phases in roller-ski skating, showing the potential of using a single IMU to estimate different spatiotemporal parameters of human locomotion.
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Pomper, Ulrich, and Ulrich Ansorge. "Theta-Rhythmic Oscillation of Working Memory Performance." Psychological Science 32, no. 11 (September 30, 2021): 1801–10. http://dx.doi.org/10.1177/09567976211013045.
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Representations held in working memory are crucial in guiding human attention in a goal-directed fashion. Currently, it is debated whether only a single representation or several of these representations can be active and bias behavior at any given moment. In the present study, 25 university students performed a behavioral dense-sampling experiment to produce an estimate of the temporal-activation patterns of two simultaneously held visual templates. We report two key novel results. First, performance related to both representations was not continuous but fluctuated rhythmically at 6 Hz. This corresponds to neural oscillations in the theta band, the functional importance of which in working memory is well established. Second, our findings suggest that two concurrently held representations may be prioritized in alternation, not simultaneously. Our data extend recent research on rhythmic sampling of external information by demonstrating an analogous mechanism in the cyclic activation of internal working memory representations.
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Wu, Qiyan, and Jianquan Cheng. "A temporally cyclic growth model of urban spatial morphology in China: Evidence from Kunming Metropolis." Urban Studies 56, no. 8 (May 22, 2018): 1533–53. http://dx.doi.org/10.1177/0042098018767614.
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Rapid urbanisation and complexity of political-economic transition in China has brought about continuous and remarkable changes of urban morphology over the past decades, which were driven by a mixture of spatial, social-economic and institutional forces. Understanding such urban morphological evolution requires new mixed evidence and holistic perspectives. In this paper, it is argued that two dominant types of urban growth in China: low-density expansion and high-density infill, might be driven by different forces at different stages. To interpret the processes of urban development, two easy-to-understand morphological indicators: ‘expansion-induced investment density index’ (EID) and ‘infill-induced investment density index’ (IID), are defined to measure the investment density per unit of developed land and used to compare the morphological changes between different phases in a long period by integrating spatial and socio-economic data. The temporal variation of these indicators suggests a cyclic growth model (CGM), which means the periodic switch between low-density expansion and high-density infill. Using Kunming metropolis as a case study, this paper has confirmed that its urban morphological evolution from 1950 to 2014 was periodically and reciprocally driven by a set of vis-à-vis dualistic dynamics, in which low-density expansion is led by pro-growth infrastructure-oriented public investment, while the high-density infill is activated by collective and rational actions of individual enterprises and their economic behaviours. It is concluded that the confirmed CGM model, together with two morphological indicators, offers a new holistic perspective and method to easily and integrally interpret urban morphological evolution and accordingly has potential theoretical implications for reasonably understanding the urbanisation in China.