Stable operating regime for traveling wave devices

DOEpatents

Carlsten, Bruce E.

2000-01-01

Autophase stability is provided for a traveling wave device (TWD) electron beam for amplifying an RF electromagnetic wave in walls defining a waveguide for said electromagnetic wave. An off-axis electron beam is generated at a selected energy and has an energy noise inherently arising from electron gun. The off-axis electron beam is introduced into the waveguide. The off-axis electron beam is introduced into the waveguide at a second radius. The waveguide structure is designed to obtain a selected detuning of the electron beam. The off-axis electron beam has a velocity and the second radius to place the electron beam at a selected distance from the walls defining the waveguide, wherein changes in a density of the electron beam due to the RF electromagnetic wave are independent of the energy of the electron beam to provide a concomitant stable operating regime relative to the energy noise.

Two-bunch operation with ns temporal separation at the FERMI FEL facility

NASA Astrophysics Data System (ADS)

Penco, Giuseppe; Allaria, Enrico; Bassanese, Silvano; Cinquegrana, Paolo; Cleva, Stefano; Danailov, Miltcho B.; Demidovich, Alexander; Ferianis, Mario; Gaio, Giulio; Giannessi, Luca; Masciovecchio, Claudio; Predonzani, Mauro; Rossi, Fabio; Roussel, Eleonore; Spampinati, Simone; Trovò, Mauro

2018-05-01

In the last decade, a continuous effort has been dedicated to extending the capabilities of existing free-electron lasers (FELs) operating in the x-ray and vacuum ultraviolet regimes. In this framework, the generation of two-color (or multi-color) temporally separated FEL pulses, has paved the way to new x-ray pump and probe experiments and several two-color two-pulse schemes have been implemented at the main facilities, but with a generally limited time-separation between the pulses, from 0 to few hundreds of fs. This limitation may be overcome by generating light with two independent electron bunches, temporally separated by integral multiples of the radio-frequency period. This solution was investigated at FERMI, measurements and characterization of this two-bunch mode of operation are presented, including trajectory control, impact of longitudinal and transverse wakefields, manipulation of the longitudinal phase space and finally a demonstration of suitability of the scheme to provide extreme ultraviolet light by using both bunches.

Conditioning of the Stable, Discrete-time Lyapunov Operator

NASA Technical Reports Server (NTRS)

Tippett, Michael K.; Cohn, Stephen E.; Todling, Ricardo; Marchesin, Dan

2000-01-01

The Schatten p-norm condition of the discrete-time Lyapunov operator L(sub A) defined on matrices P is identical with R(sup n X n) by L(sub A) P is identical with P - APA(sup T) is studied for stable matrices A is a member of R(sup n X n). Bounds are obtained for the norm of L(sub A) and its inverse that depend on the spectrum, singular values and radius of stability of A. Since the solution P of the the discrete-time algebraic Lyapunov equation (DALE) L(sub A)P = Q can be ill-conditioned only when either L(sub A) or Q is ill-conditioned, these bounds are useful in determining whether P admits a low-rank approximation, which is important in the numerical solution of the DALE for large n.

Stable Short-Term Frequency Support Using Adaptive Gains for a DFIG-Based Wind Power Plant

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

Lee, Jinsik; Jang, Gilsoo; Muljadi, Eduard

For the fixed-gain inertial control of wind power plants (WPPs), a large gain setting provides a large contribution to supporting system frequency control, but it may cause over-deceleration for a wind turbine generator that has a small amount of kinetic energy (KE). Further, if the wind speed decreases during inertial control, even a small gain may cause over-deceleration. This paper proposes a stable inertial control scheme using adaptive gains for a doubly fed induction generator (DFIG)-based WPP. The scheme aims to improve the frequency nadir (FN) while ensuring stable operation of all DFIGs, particularly when the wind speed decreases duringmore » inertial control. In this scheme, adaptive gains are set to be proportional to the KE stored in DFIGs, which is spatially and temporally dependent. To improve the FN, upon detecting an event, large gains are set to be proportional to the KE of DFIGs; to ensure stable operation, the gains decrease with the declining KE. The simulation results demonstrate that the scheme improves the FN while ensuring stable operation of all DFIGs in various wind and system conditions. Further, it prevents over-deceleration even when the wind speed decreases during inertial control.« less

Spatio-temporal environmental data tide corrections for reconnaissance operations

NASA Astrophysics Data System (ADS)

Barbu, Costin; Avera, Will; Harris, Mike; Malpass, Kevyn

2005-06-01

Dynamic, accurate near-real time environmental data is critical to the success of the mine countermeasures operations. Bathymetric data acquired from the AQS-20 mine hunting sensor should be adjusted for local tide variations related to the specific geographic area and time interval. This problem can be overcome by a spatio-temporal estimate of tide corrections provided for the area and time of interest by the Naval Research Laboratory tide prediction code PCTides. For each geographic position of the AQS-20 sonar, a tide height relative to mean sea level is computed by interpolating the tidal information from the K - nearest neighbored stations for the corresponding time. The value is used to correct the measured depth generated by the AQS-20 sonar in that location to mean sea level for fusion with other bathymetric data products. It is argued that this paper provides a useful tool to the MCM decision factors during Mine Warfare operations.

Assessing site-specific spatio-temporal variations in hydrogen and oxygen stable isotopes of human drinking water

NASA Astrophysics Data System (ADS)

Kennedy, C. D.; Bowen, G. J.; Ehleringer, J. R.

2008-12-01

Stable isotope ratios of hydrogen and oxygen (δ2H and δ18O) are environmental forensic tracers that can be used to constrain the origin and movement of animals, people, and products. The fundamental assumption underlying this method is that water resources at different geographic locations have distinct and characteristic isotopic signatures that are assimilated into organic tissues. Although much is known about regional-scale spatio-temporal variability in δ2H and δ18O of water, few studies have addressed the question of how distinct these geographic and seasonal patterns are for any given site. To address this question, a 2-year survey of δ2H and δ18O in tap water from across the contiguous U.S. and Canada was conducted. The data show that seasonal variability in δ2H and δ18O of tap water is generally low (<10 ‰ for δ2H), and those with the highest variability can be classified as: a) cities or towns in areas of high climate seasonality, or b) large cities in arid or seasonally arid regions which access and switch among multiple water sources throughout the year. The data suggest that inter-annual variation in tap water isotope ratios is typically low, with a median difference for month-month pairs during the 2 sampling years of 2.7 (δ2H). The results from this study confirm the existence of temporal variability in δ2H and δ18O of tap water, but suggest that this variability in human-managed systems is highly damped and may be amenable to classification, modeling, and prediction. In all, the data provide the foundation for incorporating temporal variation in predictive models of water and organic δ2H and δ18O, leading to more robust and statistically defensible tests of geographic origin.

High voltage threshold for stable operation in a dc electron gun

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

Yamamoto, Masahiro, E-mail: masahiro@post.kek.jp; Nishimori, Nobuyuki, E-mail: n-nishim@tagen.tohoku.ac.jp

We report clear observation of a high voltage (HV) threshold for stable operation in a dc electron gun. The HV hold-off time without any discharge is longer than many hours for operation below the threshold, while it is roughly 10 min above the threshold. The HV threshold corresponds to the minimum voltage where discharge ceases. The threshold increases with the number of discharges during HV conditioning of the gun. Above the threshold, the amount of gas desorption per discharge increases linearly with the voltage difference from the threshold. The present experimental observations can be explained by an avalanche discharge modelmore » based on the interplay between electron stimulated desorption (ESD) from the anode surface and subsequent secondary electron emission from the cathode by the impact of ionic components of the ESD molecules or atoms.« less

Temporal variation of nitrogen balance within constructed wetlands treating slightly polluted water using a stable nitrogen isotope experiment.

PubMed

Zhang, Wanguang; Lei, Qiongye; Li, Zhengkui; Han, Huayang

2016-02-01

Slightly polluted water has become one of the main sources of nitrogen contaminants in recent years, for which constructed wetlands (CW) is a typical and efficient treatment. However, the knowledge about contribution of individual nitrogen removal pathways and nitrogen balance in constructed wetlands is still limited. In this study, a stable-isotope-addition experiment was performed in laboratory-scale constructed wetlands treating slightly polluted water to determine quantitative contribution of different pathways and temporal variation of nitrogen balance using Na(15)NO3 as tracer. Microbial conversion and substrate retention were found to be the dominant pathways in nitrogen removal contributing 24.4-79.9 and 8.9-70.7 %, respectively, while plant contributed only 4.6-11.1 % through direct assimilation but promoted the efficiency of other pathways. In addition, microbial conversion became the major way to remove N whereas nitrogen retained in substrate at first was gradually released to be utilized by microbes and plants over time. The findings indicated that N2 emission representing microbial conversion was not only the major but also permanent nitrogen removal process, thus keeping a high efficiency of microbial conversion is important for stable and efficient nitrogen removal in constructed wetlands.

SiC Field Effect Transistor Technology Demonstrating Prolonged Stable Operation at 500 C

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Okojie, Robert S.; Beheim, Glenn M.; Meredith, Roger; Ferrier, Terry

2006-01-01

While there have been numerous reports of short-term transistor operation at 500 degree C or above, these devices have previously not demonstrated sufficient long-term operational durability at 500 degree C to be considered viable for most envisioned applications. This paper reports the development of Silicone Carbi field effect transistors capable of long-term electrical operation at 500 degree C. A 6H-SiC MESFET was packaged and subjected to continuous electrical operation while residing in a 500 degree C oven in oxidizing air atmosphere for over 2400 hours. The transistor gain, saturation current (IDSS), and on-resistance (RDS) changed by less than 20% from initial values throughout the duration of the biased 500 degree C test. Another high-temperature packaged 6H-SiC MESFET was employed to form a simple one-stage high-temperature low-frequency voltage amplifier. This single-stage common-source amplifier demonstrated stable continuous electrical operation (negligible changes to gain and operating biases) for over 600 hours while residing in a 500 degree C air ambient oven. In both cases, increased leakage from annealing of the Schottky gate-to-channel diode was the dominant transistor degradation mechanism that limited the duration of 500 degree C electrical operation.

Temporal Simultons in Optical Parametric Oscillators

NASA Astrophysics Data System (ADS)

Jankowski, Marc; Marandi, Alireza; Phillips, C. R.; Hamerly, Ryan; Ingold, Kirk A.; Byer, Robert L.; Fejer, M. M.

2018-02-01

We report the first demonstration of a regime of operation in optical parametric oscillators (OPOs), in which the formation of temporal simultons produces stable femtosecond half-harmonic pulses. Simultons are simultaneous bright-dark solitons of a signal field at frequency ω and the pump field at 2 ω , which form in a quadratic nonlinear medium. The formation of simultons in an OPO is due to the interplay of nonlinear pulse acceleration with the timing mismatch between the pump repetition period and the cold-cavity round-trip time and is evidenced by sech2 spectra with broad instantaneous bandwidths when the resonator is detuned to a slightly longer round-trip time than the pump repetition period. We provide a theoretical description of an OPO operating in a regime dominated by these dynamics, observe the distinct features of simulton formation in an experiment, and verify our results with numerical simulations. These results represent a new regime of operation in nonlinear resonators, which can lead to efficient and scalable sources of few-cycle frequency combs at arbitrary wavelengths.

Temporal variability in arctic fox diet as reflected in stable-carbon isotopes; the importance of sea ice.

PubMed

Roth, James D

2002-09-01

Consumption of marine foods by terrestrial predators can lead to increased predator densities, potentially impacting their terrestrial resources. For arctic foxes (Alopex lagopus), access to such marine foods in winter depends on sea ice, which is threatened by global climate change. To quantify the importance of marine foods (seal carrion and seal pups) and document temporal variation in arctic fox diet I measured the ratios of the stable isotopes of carbon ((13)C/(12)C) in hair of arctic foxes near Cape Churchill, Manitoba, from 1994 to 1997. These hair samples were compared to the stable carbon isotope ratios of several prey species. Isotopic differences between seasonally dimorphic pelage types indicated a diet with a greater marine content in winter when sea ice provided access to seal carrion. Annual variation in arctic fox diet in both summer and winter was correlated with lemming abundance. Marine food sources became much more important in winters with low lemming populations, accounting for nearly half of the winter protein intake following a lemming decline. Potential alternative summer foods with isotopic signatures differing from lemmings included goose eggs and caribou, but these were unavailable in winter. Reliance on marine food sources in winter during periods of low lemming density demonstrates the importance of the sea ice as a potential habitat for this arctic fox population and suggests that a continued decline in sea ice extent will disrupt an important link between the marine and terrestrial ecosystems.

Temporal Non-locality

NASA Astrophysics Data System (ADS)

Filk, Thomas

2013-04-01

In this article I investigate several possibilities to define the concept of "temporal non-locality" within the standard framework of quantum theory. In particular, I analyze the notions of "temporally non-local states", "temporally non-local events" and "temporally non-local observables". The idea of temporally non-local events is already inherent in the standard formalism of quantum mechanics, and Basil Hiley recently defined an operator in order to measure the degree of such a temporal non-locality. The concept of temporally non-local states enters as soon as "clock-representing states" are introduced in the context of special and general relativity. It is discussed in which way temporally non-local measurements may find an interesting application for experiments which test temporal versions of Bell inequalities.

Spatio-temporal texture (SpTeT) for distinguishing vulnerable from stable atherosclerotic plaque on dynamic contrast enhancement (DCE) MRI in a rabbit model

PubMed Central

Wan, Tao; Madabhushi, Anant; Phinikaridou, Alkystis; Hamilton, James A.; Hua, Ning; Pham, Tuan; Danagoulian, Jovanna; Kleiman, Ross; Buckler, Andrew J.

2014-01-01

Purpose: To develop a new spatio-temporal texture (SpTeT) based method for distinguishing vulnerable versus stable atherosclerotic plaques on DCE-MRI using a rabbit model of atherothrombosis. Methods: Aortic atherosclerosis was induced in 20 New Zealand White rabbits by cholesterol diet and endothelial denudation. MRI was performed before (pretrigger) and after (posttrigger) inducing plaque disruption with Russell's-viper-venom and histamine. Of the 30 vascular targets (segments) under histology analysis, 16 contained thrombus (vulnerable) and 14 did not (stable). A total of 352 voxel-wise computerized SpTeT features, including 192 Gabor, 36 Kirsch, 12 Sobel, 52 Haralick, and 60 first-order textural features, were extracted on DCE-MRI to capture subtle texture changes in the plaques over the course of contrast uptake. Different combinations of SpTeT feature sets, in which the features were ranked by a minimum-redundancy-maximum-relevance feature selection technique, were evaluated via a random forest classifier. A 500 iterative 2-fold cross validation was performed for discriminating the vulnerable atherosclerotic plaque and stable atherosclerotic plaque on per voxel basis. Four quantitative metrics were utilized to measure the classification results in separating between vulnerable and stable plaques. Results: The quantitative results show that the combination of five classes of SpTeT features can distinguish between vulnerable (disrupted plaques with an overlying thrombus) and stable plaques with the best AUC values of 0.9631 ± 0.0088, accuracy of 89.98% ± 0.57%, sensitivity of 83.71% ± 1.71%, and specificity of 94.55% ± 0.48%. Conclusions: Vulnerable and stable plaque can be distinguished by SpTeT based features. The SpTeT features, following validation on larger datasets, could be established as effective and reliable imaging biomarkers for noninvasively assessing atherosclerotic risk. PMID:24694153

L-Band Transmit/Receive Module for Phase-Stable Array Antennas

NASA Technical Reports Server (NTRS)

Andricos, Constantine; Edelstein, Wendy; Krimskiy, Vladimir

2008-01-01

Interferometric synthetic aperture radar (InSAR) has been shown to provide very sensitive measurements of surface deformation and displacement on the order of 1 cm. Future systematic measurements of surface deformation will require this capability over very large areas (300 km) from space. To achieve these required accuracies, these spaceborne sensors must exhibit low temporal decorrelation and be temporally stable systems. An L-band (24-cmwavelength) InSAR instrument using an electronically steerable radar antenna is suited to meet these needs. In order to achieve the 1-cm displacement accuracy, the phased array antenna requires phase-stable transmit/receive (T/R) modules. The T/R module operates at L-band (1.24 GHz) and has less than 1- deg absolute phase stability and less than 0.1-dB absolute amplitude stability over temperature. The T/R module is also high power (30 W) and power efficient (60-percent overall efficiency). The design is currently implemented using discrete components and surface mount technology. The basic T/R module architecture is augmented with a calibration loop to compensate for temperature variations, component variations, and path loss variations as a function of beam settings. The calibration circuit consists of an amplitude and phase detector, and other control circuitry, to compare the measured gain and phase to a reference signal and uses this signal to control a precision analog phase shifter and analog attenuator. An architecture was developed to allow for the module to be bidirectional, to operate in both transmit and receive mode. The architecture also includes a power detector used to maintain a transmitter power output constant within 0.1 dB. The use of a simple, stable, low-cost, and high-accuracy gain and phase detector made by Analog Devices (AD8302), combined with a very-high efficiency T/R module, is novel. While a self-calibrating T/R module capability has been sought for years, a practical and cost-effective solution has

Spatial and temporal variance in fatty acid and stable isotope signatures across trophic levels in large river systems

USGS Publications Warehouse

Fritts, Andrea; Knights, Brent C.; Lafrancois, Toben D.; Bartsch, Lynn; Vallazza, Jon; Bartsch, Michelle; Richardson, William B.; Karns, Byron N.; Bailey, Sean; Kreiling, Rebecca

2018-01-01

Fatty acid and stable isotope signatures allow researchers to better understand food webs, food sources, and trophic relationships. Research in marine and lentic systems has indicated that the variance of these biomarkers can exhibit substantial differences across spatial and temporal scales, but this type of analysis has not been completed for large river systems. Our objectives were to evaluate variance structures for fatty acids and stable isotopes (i.e. δ13C and δ15N) of seston, threeridge mussels, hydropsychid caddisflies, gizzard shad, and bluegill across spatial scales (10s-100s km) in large rivers of the Upper Mississippi River Basin, USA that were sampled annually for two years, and to evaluate the implications of this variance on the design and interpretation of trophic studies. The highest variance for both isotopes was present at the largest spatial scale for all taxa (except seston δ15N) indicating that these isotopic signatures are responding to factors at a larger geographic level rather than being influenced by local-scale alterations. Conversely, the highest variance for fatty acids was present at the smallest spatial scale (i.e. among individuals) for all taxa except caddisflies, indicating that the physiological and metabolic processes that influence fatty acid profiles can differ substantially between individuals at a given site. Our results highlight the need to consider the spatial partitioning of variance during sample design and analysis, as some taxa may not be suitable to assess ecological questions at larger spatial scales.

Stable operation of a Secure QKD system in the real-world setting

NASA Astrophysics Data System (ADS)

Tomita, Akihisa

2007-06-01

Quantum Key Distribution (QKD) now steps forward from the proof of principle to the validation of the practical feasibility. Nevertheless, the QKD technology should respond to the challenges from the real-world such as stable operation against the fluctuating environment, and security proof under the practical setting. We report our recent progress on stable operation of a QKD system, and key generation with security assurance. A QKD system should robust to temperature fluctuation in a common office environment. We developed a loop-mirror, a substitution of a Faraday mirror, to allow easy compensation for the temperature dependence of the device. Phase locking technique was also employed to synchronize the system clock to the quantum signals. This technique is indispensable for the transmission system based on the installed fiber cables, which stretch and shrink due to the temperature change. The security proof of QKD, however, has assumed the ideal conditions, such as the use of a genuine single photon source and/or unlimited computational resources. It has been highly desirable to give an assurance of security for practical systems, where the ideal conditions are no longer satisfied. We have constructed a theory to estimate the leakage information on the transmitted key under the practically attainable conditions, and have developed a QKD system equipped with software for secure key distillation. The QKD system generates the final key at the rate of 2000 bps after 20 km fiber transmission. Eavesdropper's information on the final key is guaranteed to be less than 2-7 per bit. This is the first successful generation of the secure key with quantitative assurance of the upper bound of the leakage information. It will put forth the realization of highly secure metropolitan optical communication network against any types of eavesdropping.

Evolutionarily stable and convergent stable strategies in reaction-diffusion models for conditional dispersal.

PubMed

Lam, King-Yeung; Lou, Yuan

2014-02-01

We consider a mathematical model of two competing species for the evolution of conditional dispersal in a spatially varying, but temporally constant environment. Two species are different only in their dispersal strategies, which are a combination of random dispersal and biased movement upward along the resource gradient. In the absence of biased movement or advection, Hastings showed that the mutant can invade when rare if and only if it has smaller random dispersal rate than the resident. When there is a small amount of biased movement or advection, we show that there is a positive random dispersal rate that is both locally evolutionarily stable and convergent stable. Our analysis of the model suggests that a balanced combination of random and biased movement might be a better habitat selection strategy for populations.

Approximating basins of attraction for dynamical systems via stable radial bases

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

Cavoretto, R.; De Rossi, A.; Perracchione, E.

2016-06-08

In applied sciences it is often required to model and supervise temporal evolution of populations via dynamical systems. In this paper, we focus on the problem of approximating the basins of attraction of such models for each stable equilibrium point. We propose to reconstruct the basins via an implicit interpolant using stable radial bases, obtaining the surfaces by partitioning the phase space into disjoint regions. An application to a competition model presenting jointly three stable equilibria is considered.

Operation of a wet near-field scanning optical microscope in stable zones by minimizing the resonance change of tuning forks.

PubMed

Park, Kyoung-Duck; Park, Doo Jae; Lee, Seung Gol; Choi, Geunchang; Kim, Dai-Sik; Byeon, Clare Chisu; Choi, Soo Bong; Jeong, Mun Seok

2014-02-21

A resonant shift and a decrease of resonance quality of a tuning fork attached to a conventional fiber optic probe in the vicinity of liquid is monitored systematically while varying the protrusion length and immersion depth of the probe. Stable zones where the resonance modification as a function of immersion depth is minimized are observed. A wet near-field scanning optical microscope (wet-NSOM) is operated for a sample within water by using such a stable zone.

Principles of Temporal Processing Across the Cortical Hierarchy.

PubMed

Himberger, Kevin D; Chien, Hsiang-Yun; Honey, Christopher J

2018-05-02

The world is richly structured on multiple spatiotemporal scales. In order to represent spatial structure, many machine-learning models repeat a set of basic operations at each layer of a hierarchical architecture. These iterated spatial operations - including pooling, normalization and pattern completion - enable these systems to recognize and predict spatial structure, while robust to changes in the spatial scale, contrast and noisiness of the input signal. Because our brains also process temporal information that is rich and occurs across multiple time scales, might the brain employ an analogous set of operations for temporal information processing? Here we define a candidate set of temporal operations, and we review evidence that they are implemented in the mammalian cerebral cortex in a hierarchical manner. We conclude that multiple consecutive stages of cortical processing can be understood to perform temporal pooling, temporal normalization and temporal pattern completion. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

An experimental study of the stable and unstable operation of an LPP gas turbine combustor

NASA Astrophysics Data System (ADS)

Dhanuka, Sulabh Kumar

A study was performed to better understand the stable operation of an LPP combustor and formulate a mechanism behind the unstable operation. A unique combustor facility was developed at the University of Michigan that incorporates the latest injector developed by GE Aircraft Engines and enables operation at elevated pressures with preheated air at flow-rates reflective of actual conditions. The large optical access has enabled the use of a multitude of state-of-the-art laser diagnostics such as PIV and PLIF, and has shed invaluable light not only into the GE injector specifically but also into gas turbine combustors in general. Results from Particle Imaging Velocimetry (PIV) have illustrated the role of velocity, instantaneous vortices, and key recirculation zones that are all critical to the combustor's operation. It was found that considerable differences exist between the iso-thermal and reacting flows, and between the instantaneous and mean flow fields. To image the flame, Planar Laser Induced Fluorescence (PLIF) of the formaldehyde radical was successfully utilized for the first time in a Jet-A flame. Parameters regarding the flame's location and structure have been obtained that assist in interpreting the velocity results. These results have also shown that some of the fuel injected from the main fuel injectors actually reacts in the diffusion flame of the pilot. The unstable operation of the combustor was studied in depth to obtain the stability limits of the combustor, behavior of the flame dynamics, and frequencies of the oscillations. Results from simultaneous pressure and high speed chemiluminescence images have shown that the low frequency dynamics can be characterized as flashback oscillations. The results have also shown that the stability of the combustor can be explained by simple and well established premixed flame stability mechanisms. This study has allowed the development of a model that describes the instability mechanism and accurately

Advanced diagnosis of the temporal characteristics of ultra-short electron beams

NASA Astrophysics Data System (ADS)

Otake, Yuji

2011-05-01

Monitoring the temporal structure of an ultra-short electron beam is an indispensable function in order to tune a machine to obtain a highly qualified beam for a recent sophisticated accelerator, such as an X-ray free electron laser (XFEL), and to maintain stable X-ray laser operation. For this purpose, various instruments, such as an HEM11-mode RF beam deflector (RFDEF), a screen monitor (SCM), an electro-optic (EO) sampling method that uses a ZnTe crystal, and a beam position monitor (BPM) have been developed. The SCM that is used to observe the deflected beam image has a position resolution of 2.5 μm, which corresponds to a temporal resolution of 0.5 fs and it is installed at a position 5 m downstream from the RFDEF. The EO sampling method showed the ability to observe an electron bunch length for up to 300 fs (FWHM) at the SCSS test accelerator. The phase reference cavity of the BPM has an additional function of providing beam arrival timing information. A test for the BPM showed temporal fluctuation of 46 fs on the beam arrival timing at the test accelerator. These monitors with high temporal resolutions allow us to achieve the fine beam tuning demanded for the XFEL. The above-mentioned activities are described in this paper as a review article.

High-Order Entropy Stable Formulations for Computational Fluid Dynamics

NASA Technical Reports Server (NTRS)

Carpenter, Mark H.; Fisher, Travis C.

2013-01-01

A systematic approach is presented for developing entropy stable (SS) formulations of any order for the Navier-Stokes equations. These SS formulations discretely conserve mass, momentum, energy and satisfy a mathematical entropy inequality. They are valid for smooth as well as discontinuous flows provided sufficient dissipation is added at shocks and discontinuities. Entropy stable formulations exist for all diagonal norm, summation-by-parts (SBP) operators, including all centered finite-difference operators, Legendre collocation finite-element operators, and certain finite-volume operators. Examples are presented using various entropy stable formulations that demonstrate the current state-of-the-art of these schemes.

Towards operational hydrology for a thorough spatio-temporal exploration of the Critical Zone

NASA Astrophysics Data System (ADS)

Chatton, Eliot; Labasque, Thierry; Guillou, Aurélie; Aquilina, Luc; Bour, Olivier; Le Borgne, Tanguy; Longuevergne, Laurent

2017-04-01

Over the last century, the Critical Zone faced remarkable climate and land use changes increasing the pressures on the Hydrosphere and giving rise to numerous environmental consequences in terms of water quantity and quality. From now on, the Critical Zone must face the challenge to supply 9 billion people with quality food and safe drinking water in a context of global warming. For the Hydrosphere, this challenge could be addressed with a better understanding of the dynamics and resilience of aquatic environments (rivers, lakes, groundwaters, oceans). In view of the spatial and temporal variety and variability of flow dynamics and biogeochemical reactions occurring in the Hydrosphere a new investigation method is needed. This study approaches the concept of "operational hydrology" aiming to enhance either the spatio-temporal distribution and the quality of environmental data for a thorough exploration of the Hydrosphere. To illustrate our approach, we present natural and anthropogenic dissolved gas data (He, Ne, Ar, Kr, Xe, N2, O2, CO2, CH4, N2O, H2, BTEX, and some VOCs) measured in situ with a CF-MIMS (Chatton et al, 2016) installed in a mobile laboratory arranged in an all-terrain truck (CRITEX-Lab). This ongoing work focuses on groundwater and the field investigation of residence time distributions, recharge processes (origins), water flow paths and mixing, biogeochemical reactivity and contamination (sources). The rationale behind "operational hydrology" could be applied to the field measurement at high-frequency of many other environmental parameters (temperature, cations, anions, isotopes, micro-organisms) not only for the investigation of groundwaters but also rivers, lakes and oceans. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour and Luc Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow; Environmental Science

STABLE ISOTOPES AS INDICATORS OF SOIL WATER DYNAMICS IN WATERSHEDS

EPA Science Inventory

Stream water quality and quantity depend on discharge rates of water and nutrients from soils. However, soil-water storage is very dynamic and strongly influenced by plants. We analyzed stable isotopes of oxygen and hydrogen to quantify spatial and temporal changes in evaporati...

Does the ocean-atmosphere system have more than one stable mode of operation?

NASA Technical Reports Server (NTRS)

Broecker, W. S.; Peteet, D. M.; Rind, D.

1985-01-01

The climate record obtained from two long Greenland ice cores reveals several brief climate oscillations during glacial time. The most recent of these oscillations, also found in continental pollen records, has greatest impact in the area under the meteorological influence of the northern Atlantic, but none in the United States. This suggests that these oscillations are caused by fluctuations in the formation rate of deep water in the northern Atlantic. As the present production of deep water in this area is driven by an excess of evaporation over precipitation and continental runoff, atmospheric water transport may be an important element in climate change. Changes in the production rate of deep water in this sector of the ocean may push the climate system from one quasi-stable mode of operation to another.

[Startup, stable operation and process failure of EBPR system under the low temperature and low dissolved oxygen condition].

PubMed

Ma, Juan; Li, Lu; Yu, Xiao-Jun; Wei, Xue-Fen; Liu, Juan-Li

2015-02-01

A sequencing batch reactor (SBR) was started up and operated with alternating anaerobic/oxic (An/O) to perform enhanced biological phosphorus removal (EBPR) under the condition of 13-16 degrees C. The results showed that under the condition of low temperature, the EBPR system was successfully started up in a short time (<6 d). The reactor achieved a high and stable phosphorus removal performance with an influent phosphate concentration of 20 mg x L(-1) and the dissolved oxygen (DO) concentration of 2 mg x L(-1). The effluent phosphate concentration was lower than 0.5 mg x L(-1). It was found that decreasing DO had an influence on the steady operation of EBPR system. As DO concentration of aerobic phase decreased from 2 mg x L(-1) to 1 mg x L(-1), the system could still perform EBPR and the phosphorus removal efficiency was greater than 97.4%. However, the amount of phosphate released during anaerobic phase was observed to decrease slightly compared with that of 2 mg x L(-1) DO condition. Moreover, the phosphorus removal performance of the system deteriorated immediately and the effluent phosphate concentration couldn't meet the national integrated wastewater discharge standard when DO concentration was further lowered to 0.5 mg x L(-1). The experiments of increasing DO to recover phosphorus removal performance of the EBPR suggested the process failure resulted from low DO was not reversible in the short-term. It was also found that the batch tests of anoxic phosphorus uptake using nitrite and nitrate as electron acceptors had an impact on the stable operation of EBPR system, whereas the resulting negative influence could be recovered within 6 cycles. In addition, the mixed liquid suspended solids (MLSS) of the EBPR system remained stable and the sludge volume index (SVI) decreased to a certain extend in a long run, implying long-term low temperature and low DO condition favored the sludge sedimentation.

Ultrasound assisted synthesis of stable oil in milk emulsion: Study of operating parameters and scale-up aspects.

PubMed

Patil, Leena; Gogate, Parag R

2018-01-01

In the present work, application of ultrasound and stirring individually or in combination for improved emulsification of turmeric oil in skimmed milk has been investigated. The effect of different operating parameters/strategies such as addition of surfactant, sodium dodecyl sulfate (SDS), at different concentrations, quantity of oil phase, applied power, sonication time and duty cycle on the droplet size have been investigated. The stability of emulsion was analyzed in terms of the fraction of the emulsion that remains stable for a period of 28days. Optimized set of major emulsification process variables has been used at higher emulsion volumes. The effectiveness of treatment approach was analyzed based on oil droplet size, energy density and the time required for the formation of stable emulsion. It was observed that the stable emulsion at 50mL capacity with mean droplet diameter of about 235.4nm was obtained with the surfactant concentration of 5mg/mL, 11% of rated power (power density: 0.31W/mL) and irradiation time of 5min. The emulsion stability was higher in the case of ultrasound assisted approach as compared to the stirring. For the preparation of stable emulsion at 300mL capacity, it was observed that the sequential approach, i.e., stirring followed by ultrasound, gave lower mean droplet diameter (232.6nm) than the simultaneous approach, i.e., ultrasound and stirring together (257.9nm). However, the study also revealed that the simultaneous approach required very less time (15min) to synthesize stable emulsion as compared to the sequential approach (30min stirring and 60min ultrasound). It was successfully demonstrated that the ultrasound-assisted emulsification in the presence of SDS could be used for the preparation of stable turmeric oil-dairy emulsions, also providing insights into the role of SDS in increasing the stability of emulsions and of ultrasound in giving lower droplet sizes. Copyright © 2017 Elsevier B.V. All rights reserved.

Stable Electrical Operation of 6H-SiC JFETs and ICs for Thousands of Hours at 500 C

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Beheim, Glenn M.; Okojie, Robert S.; Chang, Carl W.; Meredith, Roger D.; Ferrier, Terry L.; Evans, Laura J.; Krasowski, Michael J.;

First stable isotope analysis of Asiatic wild ass tail hair from the Mongolian Gobi

PubMed Central

Horacek, Micha; Sturm, Martina Burnik; Kaczensky, Petra

2015-01-01

Stable isotope analysis has become a powerful tool to study feeding ecology, water use or movement pattern in contemporary, historic and ancient species. Certain hair and teeth grow continuously, and when sampled longitudinally can provide temporally explicit information on dietary regime and movement pattern. In an initial trial, we analysed a tail sample of an Asiatic wild ass (Equus hemionus) from the Mongolian Gobi. We found seasonal variations in H, C and N isotope patterns, likely being the result of temporal variations in available feeds, water supply and possibly physiological status. Thus stable isotope analysis shows promise to study the comparative ecology of the three autochthonous equid species in the Mongolian Gobi. PMID:26339116

First stable isotope analysis of Asiatic wild ass tail hair from the Mongolian Gobi.

PubMed

Horacek, Micha; Sturm, Martina Burnik; Kaczensky, Petra

Stable isotope analysis has become a powerful tool to study feeding ecology, water use or movement pattern in contemporary, historic and ancient species. Certain hair and teeth grow continuously, and when sampled longitudinally can provide temporally explicit information on dietary regime and movement pattern. In an initial trial, we analysed a tail sample of an Asiatic wild ass ( Equus hemionus ) from the Mongolian Gobi. We found seasonal variations in H, C and N isotope patterns, likely being the result of temporal variations in available feeds, water supply and possibly physiological status. Thus stable isotope analysis shows promise to study the comparative ecology of the three autochthonous equid species in the Mongolian Gobi.

Design techniques for a stable operation of cryogenic field-programmable gate arrays.

PubMed

Homulle, Harald; Visser, Stefan; Patra, Bishnu; Charbon, Edoardo

2018-01-01

In this paper, we show how a deep-submicron field-programmable gate array (FPGA) can be operated more stably at extremely low temperatures through special firmware design techniques. Stability at low temperatures is limited through long power supply wires and reduced performance of various printed circuit board components commonly employed at room temperature. Extensive characterization of these components shows that the majority of decoupling capacitor types and voltage regulators are not well behaved at cryogenic temperatures, asking for an ad hoc solution to stabilize the FPGA supply voltage, especially for sensitive applications. Therefore, we have designed a firmware that enforces a constant power consumption, so as to stabilize the supply voltage in the interior of the FPGA. The FPGA is powered with a supply at several meters distance, causing significant resistive voltage drop and thus fluctuations on the local supply voltage. To achieve the stabilization, the variation in digital logic speed, which directly corresponds to changes in supply voltage, is constantly measured and corrected for through a tunable oscillator farm, implemented on the FPGA. The impact of the stabilization technique is demonstrated together with a reconfigurable analog-to-digital converter (ADC), completely implemented in the FPGA fabric and operating at 15 K. The ADC performance can be improved by at most 1.5 bits (effective number of bits) thanks to the more stable supply voltage. The method is versatile and robust, enabling seamless porting to other FPGA families and configurations.

Design techniques for a stable operation of cryogenic field-programmable gate arrays

NASA Astrophysics Data System (ADS)

Homulle, Harald; Visser, Stefan; Patra, Bishnu; Charbon, Edoardo

2018-01-01

In this paper, we show how a deep-submicron field-programmable gate array (FPGA) can be operated more stably at extremely low temperatures through special firmware design techniques. Stability at low temperatures is limited through long power supply wires and reduced performance of various printed circuit board components commonly employed at room temperature. Extensive characterization of these components shows that the majority of decoupling capacitor types and voltage regulators are not well behaved at cryogenic temperatures, asking for an ad hoc solution to stabilize the FPGA supply voltage, especially for sensitive applications. Therefore, we have designed a firmware that enforces a constant power consumption, so as to stabilize the supply voltage in the interior of the FPGA. The FPGA is powered with a supply at several meters distance, causing significant resistive voltage drop and thus fluctuations on the local supply voltage. To achieve the stabilization, the variation in digital logic speed, which directly corresponds to changes in supply voltage, is constantly measured and corrected for through a tunable oscillator farm, implemented on the FPGA. The impact of the stabilization technique is demonstrated together with a reconfigurable analog-to-digital converter (ADC), completely implemented in the FPGA fabric and operating at 15 K. The ADC performance can be improved by at most 1.5 bits (effective number of bits) thanks to the more stable supply voltage. The method is versatile and robust, enabling seamless porting to other FPGA families and configurations.

Robust temporal alignment of multimodal cardiac sequences

NASA Astrophysics Data System (ADS)

Perissinotto, Andrea; Queirós, Sandro; Morais, Pedro; Baptista, Maria J.; Monaghan, Mark; Rodrigues, Nuno F.; D'hooge, Jan; Vilaça, João. L.; Barbosa, Daniel

2015-03-01

Given the dynamic nature of cardiac function, correct temporal alignment of pre-operative models and intraoperative images is crucial for augmented reality in cardiac image-guided interventions. As such, the current study focuses on the development of an image-based strategy for temporal alignment of multimodal cardiac imaging sequences, such as cine Magnetic Resonance Imaging (MRI) or 3D Ultrasound (US). First, we derive a robust, modality-independent signal from the image sequences, estimated by computing the normalized cross-correlation between each frame in the temporal sequence and the end-diastolic frame. This signal is a resembler for the left-ventricle (LV) volume curve over time, whose variation indicates different temporal landmarks of the cardiac cycle. We then perform the temporal alignment of these surrogate signals derived from MRI and US sequences of the same patient through Dynamic Time Warping (DTW), allowing to synchronize both sequences. The proposed framework was evaluated in 98 patients, which have undergone both 3D+t MRI and US scans. The end-systolic frame could be accurately estimated as the minimum of the image-derived surrogate signal, presenting a relative error of 1.6 +/- 1.9% and 4.0 +/- 4.2% for the MRI and US sequences, respectively, thus supporting its association with key temporal instants of the cardiac cycle. The use of DTW reduces the desynchronization of the cardiac events in MRI and US sequences, allowing to temporally align multimodal cardiac imaging sequences. Overall, a generic, fast and accurate method for temporal synchronization of MRI and US sequences of the same patient was introduced. This approach could be straightforwardly used for the correct temporal alignment of pre-operative MRI information and intra-operative US images.

Operations automation using temporal dependency networks

NASA Technical Reports Server (NTRS)

Cooper, Lynne P.

1991-01-01

Precalibration activities for the Deep Space Network are time- and work force-intensive. Significant gains in availability and efficiency could be realized by intelligently incorporating automation techniques. An approach is presented to automation based on the use of Temporal Dependency Networks (TDNs). A TDN represents an activity by breaking it down into its component pieces and formalizing the precedence and other constraints associated with lower level activities. The representations are described which are used to implement a TDN and the underlying system architecture needed to support its use. The commercial applications of this technique are numerous. It has potential for application in any system which requires real-time, system-level control, and accurate monitoring of health, status, and configuration in an asynchronous environment.

Highly stable self-pulsed operation of an Er:Lu2O3 ceramic laser at 2.7 µm

NASA Astrophysics Data System (ADS)

Wang, Li; Huang, Haitao; Shen, Deyuan; Zhang, Jian; Chen, Hao; Tang, Dingyuan

2017-04-01

We report on the highly stable self-pulsed operation of a 2.74 µm Er:Lu2O3 ceramic laser pumped by a wavelength locked narrow bandwidth 976 nm laser diode. The operating pulse repetition rate is continuously tunable from 126 kHz to 270 kHz depending on the pump power level. For 12.3 W of absorbed diode pump power, the Er:Lu2O3 ceramic laser generates 820 mW of average output power at a 270 kHz repetition rate and with a pulse duration of 183 ns. The corresponding pulse-to-pulse amplitude fluctuation is estimated to be less than 0.7%. In the continues-wave (CW) mode of operation, the laser yields over 1.3 W of output power with a slope efficiency of 11.9% with respect to the 976 nm pump power.

Temporal Stability of Multiple Response Systems to 7.5% Carbon Dioxide Challenge

PubMed Central

Roberson-Nay, Roxann; Gorlin, Eugenia I.; Beadel, Jessica R.; Cash, Therese; Vrana, Scott; Teachman, Bethany A.

2017-01-01

Self-reported anxiety, and potentially physiological response, to maintained inhalation of carbon dioxide (CO2) enriched air shows promise as a putative marker of panic reactivity and vulnerability. Temporal stability of response systems during low-dose, steady-state CO2 breathing challenge is lacking. Outcomes on multiple levels were measured two times, one week apart, in 93 individuals. Stability was highest during the CO2 breathing phase compared to pre-CO2 and recovery phases, with anxiety ratings, respiratory rate, skin conductance level, and heart rate demonstrating good to excellent temporal stability (ICCs ≥ 0.71). Cognitive symptoms tied to panic were somewhat less stable (ICC = 0.58) than physical symptoms (ICC = 0.74) during CO2 breathing. Escape/avoidance behaviors and DSM-5 panic attacks were not stable. Large effect sizes between task phases also were observed. Overall, results suggest good-excellent levels of temporal stability for multiple outcomes during respiratory stimulation via 7.5% CO2. PMID:28163046

Temporal system-level organization of the switch from glycolytic to gluconeogenic operation in yeast

PubMed Central

Zampar, Guillermo G; Kümmel, Anne; Ewald, Jennifer; Jol, Stefan; Niebel, Bastian; Picotti, Paola; Aebersold, Ruedi; Sauer, Uwe; Zamboni, Nicola; Heinemann, Matthias

2013-01-01

The diauxic shift in Saccharomyces cerevisiae is an ideal model to study how eukaryotic cells readjust their metabolism from glycolytic to gluconeogenic operation. In this work, we generated time-resolved physiological data, quantitative metabolome (69 intracellular metabolites) and proteome (72 enzymes) profiles. We found that the diauxic shift is accomplished by three key events that are temporally organized: (i) a reduction in the glycolytic flux and the production of storage compounds before glucose depletion, mediated by downregulation of phosphofructokinase and pyruvate kinase reactions; (ii) upon glucose exhaustion, the reversion of carbon flow through glycolysis and onset of the glyoxylate cycle operation triggered by an increased expression of the enzymes that catalyze the malate synthase and cytosolic citrate synthase reactions; and (iii) in the later stages of the adaptation, the shutting down of the pentose phosphate pathway with a change in NADPH regeneration. Moreover, we identified the transcription factors associated with the observed changes in protein abundances. Taken together, our results represent an important contribution toward a systems-level understanding of how this adaptation is realized. PMID:23549479

Spatio-temporal pattern clustering for skill assessment of the Korea Operational Oceanographic System

NASA Astrophysics Data System (ADS)

Kim, J.; Park, K.

2016-12-01

In order to evaluate the performance of operational forecast models in the Korea operational oceanographic system (KOOS) which has been developed by Korea Institute of Ocean Science and Technology (KIOST), a skill assessment (SA) tool has developed and provided multiple skill metrics including not only correlation and error skills by comparing predictions and observation but also pattern clustering with numerical models, satellite, and observation. The KOOS has produced 72 hours forecast information on atmospheric and hydrodynamic forecast variables of wind, pressure, current, tide, wave, temperature, and salinity at every 12 hours per day produced by operating numerical models such as WRF, ROMS, MOM5, WW-III, and SWAN and the SA has conducted to evaluate the forecasts. We have been operationally operated several kinds of numerical models such as WRF, ROMS, MOM5, MOHID, WW-III. Quantitative assessment of operational ocean forecast model is very important to provide accurate ocean forecast information not only to general public but also to support ocean-related problems. In this work, we propose a method of pattern clustering using machine learning method and GIS-based spatial analytics to evaluate spatial distribution of numerical models and spatial observation data such as satellite and HF radar. For the clustering, we use 10 or 15 years-long reanalysis data which was computed by the KOOS, ECMWF, and HYCOM to make best matching clusters which are classified physical meaning with time variation and then we compare it with forecast data. Moreover, for evaluating current, we develop extraction method of dominant flow and apply it to hydrodynamic models and HF radar's sea surface current data. By applying pattern clustering method, it allows more accurate and effective assessment of ocean forecast models' performance by comparing not only specific observation positions which are determined by observation stations but also spatio-temporal distribution of whole model

Temporal plus epilepsy is a major determinant of temporal lobe surgery failures.

PubMed

Barba, Carmen; Rheims, Sylvain; Minotti, Lorella; Guénot, Marc; Hoffmann, Dominique; Chabardès, Stephan; Isnard, Jean; Kahane, Philippe; Ryvlin, Philippe

2016-02-01

Reasons for failed temporal lobe epilepsy surgery remain unclear. Temporal plus epilepsy, characterized by a primary temporal lobe epileptogenic zone extending to neighboured regions, might account for a yet unknown proportion of these failures. In this study all patients from two epilepsy surgery programmes who fulfilled the following criteria were included: (i) operated from an anterior temporal lobectomy or disconnection between January 1990 and December 2001; (ii) magnetic resonance imaging normal or showing signs of hippocampal sclerosis; and (iii) postoperative follow-up ≥ 24 months for seizure-free patients. Patients were classified as suffering from unilateral temporal lobe epilepsy, bitemporal epilepsy or temporal plus epilepsy based on available presurgical data. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom over time. Predictors of seizure recurrence were investigated using Cox proportional hazards model. Of 168 patients included, 108 (63.7%) underwent stereoelectroencephalography, 131 (78%) had hippocampal sclerosis, 149 suffered from unilateral temporal lobe epilepsy (88.7%), one from bitemporal epilepsy (0.6%) and 18 (10.7%) from temporal plus epilepsy. The probability of Engel class I outcome at 10 years of follow-up was 67.3% (95% CI: 63.4-71.2) for the entire cohort, 74.5% (95% CI: 70.6-78.4) for unilateral temporal lobe epilepsy, and 14.8% (95% CI: 5.9-23.7) for temporal plus epilepsy. Multivariate analyses demonstrated four predictors of seizure relapse: temporal plus epilepsy (P < 0.001), postoperative hippocampal remnant (P = 0.001), past history of traumatic or infectious brain insult (P = 0.022), and secondary generalized tonic-clonic seizures (P = 0.023). Risk of temporal lobe surgery failure was 5.06 (95% CI: 2.36-10.382) greater in patients with temporal plus epilepsy than in those with unilateral temporal lobe epilepsy. Temporal plus epilepsy represents a hitherto unrecognized prominent cause of

Multi-operational tuneable Q-switched mode-locking Er fibre laser

NASA Astrophysics Data System (ADS)

Qamar, F. Z.

2018-01-01

A wavelength-spacing tuneable, Q-switched mode-locking (QML) erbium-doped fibre laser based on non-linear polarization rotation controlled by four waveplates and a cube polarizer is proposed. A mode-locked pulse train using two quarter-wave plates and a half-wave plate (HWP) is obtained first, and then an extra HWP is inserted into the cavity to produce different operation regimes. The evolutions of temporal and spectral dynamics with different orientation angles of the extra HWP are investigated. A fully modulated stable QML pulse train is observed experimentally. This is, to the author’s best knowledge, the first experimental work reporting QML operation without adding an extra saturable absorber inside the laser cavity. Multi-wavelength pulse laser operation, multi-pulse train continuous-wave mode-locking operation and pulse-splitting operations are also reported at certain HWP angles. The observed operational dynamics are interpreted as a mutual interaction of dispersion, non-linear effect and insertion loss. This work provides a new mechanism for fabricating cheap tuneable multi-wavelength lasers with QML pulses.

Migrating Myeloid Cells Sense Temporal Dynamics of Chemoattractant Concentrations.

PubMed

Petrie Aronin, Caren E; Zhao, Yun M; Yoon, Justine S; Morgan, Nicole Y; Prüstel, Thorsten; Germain, Ronald N; Meier-Schellersheim, Martin

2017-11-21

Chemoattractant-mediated recruitment of hematopoietic cells to sites of pathogen growth or tissue damage is critical to host defense and organ homeostasis. Chemotaxis is typically considered to rely on spatial sensing, with cells following concentration gradients as long as these are present. Utilizing a microfluidic approach, we found that stable gradients of intermediate chemokines (CCL19 and CXCL12) failed to promote persistent directional migration of dendritic cells or neutrophils. Instead, rising chemokine concentrations were needed, implying that temporal sensing mechanisms controlled prolonged responses to these ligands. This behavior was found to depend on G-coupled receptor kinase-mediated negative regulation of receptor signaling and contrasted with responses to an end agonist chemoattractant (C5a), for which a stable gradient led to persistent migration. These findings identify temporal sensing as a key requirement for long-range myeloid cell migration to intermediate chemokines and provide insights into the mechanisms controlling immune cell motility in complex tissue environments. Published by Elsevier Inc.

Towards more stable operation of the Tokyo Tier2 center

NASA Astrophysics Data System (ADS)

Nakamura, T.; Mashimo, T.; Matsui, N.; Sakamoto, H.; Ueda, I.

2014-06-01

(Tokyo to New York and Tokyo to Los Angeles). The new line will be connected to LHCONE for the more improvement of the connectivity. In this circumstance, we are working for the further stable operation. For instance, we have newly introduced GPFS (IBM) for the non-grid disk storage, while Disk Pool Manager (DPM) are continued to be used as Tier2 disk storage from the previous system. Since the number of files stored in a DPM pool will be increased with increasing the total amount of data, the development of stable database configuration is one of the crucial issues as well as scalability. We have started some studies on the performance of asynchronous database replication so that we can take daily full backup. In this report, we would like to introduce several improvements in terms of the performances and stability of our new system and possibility of the further improvement of local I/O performance in the multi-core worker node. We also present the status of the wide area network connectivity from Japan to US and/or EU with LHCONE.

Development of operationally stable inverted organic light-emitting diode prepared without using alkali metals (Presentation Recording)

NASA Astrophysics Data System (ADS)

Fukagawa, Hirohiko; Morii, Katsuyuki; Hasegawa, Munehiro; Gouda, Shun; Tsuzuki, Toshimitsu; Shimizu, Takahisa; Yamamoto, Toshihiro

2015-10-01

The OLED is one of the key devices for realizing future flexible displays and lightings. One of the biggest challenges left for the OLED fabricated on a flexible substrate is the improvement of its resistance to oxygen and moisture. A high barrier layer [a water vapor transmission rate (WVTR) of about 10-6 g/m2/day] is proposed to be necessary for the encapsulation of conventional OLEDs. Some flexible high barrier layers have recently been demonstrated; however, such high barrier layers require a complex process, which makes flexible OLEDs expensive. If an OLED is prepared without using air-sensitive materials such as alkali metals, no stringent encapsulation is necessary for such an OLED. In this presentation, we will discuss our continuing efforts to develop an inverted OLED (iOLED) prepared without using alkali metals. iOLEDs with a bottom cathode are considered to be effective for realizing air-stable OLEDs since the electron injection layer (EIL) can be prepared by fabrication processes that might damage the organic layers, resulting in the enhanced range of materials suitable for EILs. We have demonstrated that a highly efficient and relatively air-stable iOLED can be realized by employing poly(ethyleneimine) as an EIL. Dark spot formation was not observed after 250 days in the poly(ethyleneimine)-based iOLED encapsulated by a barrier film with a WVTR of 10-4 g/m2/day. In addition, we have demonstrated the fabrication of a highly operational stable iOLED utilizing a newly developed EIL. The iOLED exhibits an expected half-lifetime of over 10,000 h from an initial luminance of 1,000 cd/m2.

Mini-Mega-TORTORA wide-field monitoring system with sub-second temporal resolution: first year of operation

NASA Astrophysics Data System (ADS)

Karpov, S.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Perkov, A.; Sasyuk, V.

2016-12-01

Here we present the summary of first years of operation and the first results of a novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-Mega-TORTORA (MMT-9), which is in operation now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (˜900 square degrees) or narrow (˜100 square degrees) fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds. The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by MMT include faint meteors and artificial satellites. The pipeline for a longer time scales variability analysis is still in development.

Temporal Stability of Genetic Variability and Differentiation in the Three-Spined Stickleback (Gasterosteus aculeatus)

PubMed Central

DeFaveri, Jacquelin; Merilä, Juha

2015-01-01

Temporal variation in allele frequencies, whether caused by deterministic or stochastic forces, can inform us about interesting demographic and evolutionary phenomena occurring in wild populations. In spite of the continued surge of interest in the genetics of three-spined stickleback (Gasterosteus aculeatus) populations, little attention has been paid towards the temporal stability of allele frequency distributions, and whether there are consistent differences in effective size (Ne) of local populations. We investigated temporal stability of genetic variability and differentiation in 15 microsatellite loci within and among eight collection sites of varying habitat type, surveyed twice over a six-year time period. In addition, Nes were estimated with the expectation that they would be lowest in isolated ponds, intermediate in larger lakes and largest in open marine sites. In spite of the marked differences in genetic variability and differentiation among the study sites, the temporal differences in allele frequencies, as well as measures of genetic diversity and differentiation, were negligible. Accordingly, the Ne estimates were temporally stable, but tended to be lower in ponds than in lake or marine habitats. Hence, we conclude that allele frequencies in putatively neutral markers in three-spined sticklebacks seem to be temporally stable – at least over periods of few generations – across a wide range of habitat types differing markedly in levels of genetic variability, effective population size and gene flow. PMID:25853707

Temporal stability of genetic variability and differentiation in the three-spined stickleback (Gasterosteus aculeatus).

PubMed

DeFaveri, Jacquelin; Merilä, Juha

2015-01-01

Temporal variation in allele frequencies, whether caused by deterministic or stochastic forces, can inform us about interesting demographic and evolutionary phenomena occurring in wild populations. In spite of the continued surge of interest in the genetics of three-spined stickleback (Gasterosteus aculeatus) populations, little attention has been paid towards the temporal stability of allele frequency distributions, and whether there are consistent differences in effective size (Ne) of local populations. We investigated temporal stability of genetic variability and differentiation in 15 microsatellite loci within and among eight collection sites of varying habitat type, surveyed twice over a six-year time period. In addition, Nes were estimated with the expectation that they would be lowest in isolated ponds, intermediate in larger lakes and largest in open marine sites. In spite of the marked differences in genetic variability and differentiation among the study sites, the temporal differences in allele frequencies, as well as measures of genetic diversity and differentiation, were negligible. Accordingly, the Ne estimates were temporally stable, but tended to be lower in ponds than in lake or marine habitats. Hence, we conclude that allele frequencies in putatively neutral markers in three-spined sticklebacks seem to be temporally stable - at least over periods of few generations - across a wide range of habitat types differing markedly in levels of genetic variability, effective population size and gene flow.

Electrically actuatable temporal tristimulus-color device

DOEpatents

Koehler, Dale R.

1992-01-01

The electrically actuated light filter operates in a cyclical temporal mode to effect a tristimulus-color light analyzer. Construction is based on a Fabry-Perot interferometer comprised of a high-speed movable mirror pair and cyclically powered electrical actuators. When combined with a single vidicon tube or a monochrome solid state image sensor, a temporally operated tristimulus-color video camera is effected. A color-generated is accomplished when constructed with a companion light source and is a flicker-free colored-light source for transmission type display systems. Advantages of low cost and small physical size result from photolithographic batch-processing manufacturability.

Biocybernetic system evaluates indices of operator engagement in automated task

NASA Technical Reports Server (NTRS)

Pope, A. T.; Bogart, E. H.; Bartolome, D. S.

1995-01-01

A biocybernetic system has been developed as a method to evaluate automated flight deck concepts for compatibility with human capabilities. A biocybernetic loop is formed by adjusting the mode of operation of a task set (e.g., manual/automated mix) based on electroencephalographic (EEG) signals reflecting an operator's engagement in the task set. A critical issue for the loop operation is the selection of features of the EEG to provide an index of engagement upon which to base decisions to adjust task mode. Subjects were run in the closed-loop feedback configuration under four candidate and three experimental control definitions of an engagement index. The temporal patterning of system mode switching was observed for both positive and negative feedback of the index. The indices were judged on the basis of their relative strength in exhibiting expected feedback control system phenomena (stable operation under negative feedback and unstable operation under positive feedback). Of the candidate indices evaluated in this study, an index constructed according to the formula, beta power/(alpha power + theta power), reflected task engagement best.

Ensemble Solute Transport in 2-D Operator-Stable Random Fields

NASA Astrophysics Data System (ADS)

Monnig, N. D.; Benson, D. A.

2006-12-01

The heterogeneous velocity field that exists at many scales in an aquifer will typically cause a dissolved solute plume to grow at a rate faster than Fick's Law predicts. Some statistical model must be adopted to account for the aquifer structure that engenders the velocity heterogeneity. A fractional Brownian motion (fBm) model has been shown to create the long-range correlation that can produce continually faster-than-Fickian plume growth. Previous fBm models have assumed isotropic scaling (defined here by a scalar Hurst coefficient). Motivated by field measurements of aquifer hydraulic conductivity, recent techniques were developed to construct random fields with anisotropic scaling with a self-similarity parameter that is defined by a matrix. The growth of ensemble plumes is analyzed for transport through 2-D "operator- stable" fBm hydraulic conductivity (K) fields. Both the longitudinal and transverse Hurst coefficients are important to both plume growth rates and the timing and duration of breakthrough. Smaller Hurst coefficients in the transverse direction lead to more "continuity" or stratification in the direction of transport. The result is continually faster-than-Fickian growth rates, highly non-Gaussian ensemble plumes, and a longer tail early in the breakthrough curve. Contrary to some analytic stochastic theories for monofractal K fields, the plume growth rate never exceeds Mercado's [1967] purely stratified aquifer growth rate of plume apparent dispersivity proportional to mean distance. Apparent super-Mercado growth must be the result of other factors, such as larger plumes corresponding to either a larger initial plume size or greater variance of the ln(K) field.

Comparing spatial and temporal patterns of river water isotopes across networks

EPA Science Inventory

A detailed understanding of the spatial and temporal dynamics of water sources across river networks is central to managing the impacts of climate change. Because the stable isotope composition of precipitation varies geographically, variation in surface-water isotope signatures ...

The Voronoi spatio-temporal data structure

NASA Astrophysics Data System (ADS)

Mioc, Darka

2002-04-01

Current GIS models cannot integrate the temporal dimension of spatial data easily. Indeed, current GISs do not support incremental (local) addition and deletion of spatial objects, and they can not support the temporal evolution of spatial data. Spatio-temporal facilities would be very useful in many GIS applications: harvesting and forest planning, cadastre, urban and regional planning, and emergency planning. The spatio-temporal model that can overcome these problems is based on a topological model---the Voronoi data structure. Voronoi diagrams are irregular tessellations of space, that adapt to spatial objects and therefore they are a synthesis of raster and vector spatial data models. The main advantage of the Voronoi data structure is its local and sequential map updates, which allows us to automatically record each event and performed map updates within the system. These map updates are executed through map construction commands that are composed of atomic actions (geometric algorithms for addition, deletion, and motion of spatial objects) on the dynamic Voronoi data structure. The formalization of map commands led to the development of a spatial language comprising a set of atomic operations or constructs on spatial primitives (points and lines), powerful enough to define the complex operations. This resulted in a new formal model for spatio-temporal change representation, where each update is uniquely characterized by the numbers of newly created and inactivated Voronoi regions. This is used for the extension of the model towards the hierarchical Voronoi data structure. In this model, spatio-temporal changes induced by map updates are preserved in a hierarchical data structure that combines events and corresponding changes in topology. This hierarchical Voronoi data structure has an implicit time ordering of events visible through changes in topology, and it is equivalent to an event structure that can support temporal data without precise temporal

A possible mechanism of interleaving at weak baroclinic fronts under stable-stable stratification in the Arctic Basin

NASA Astrophysics Data System (ADS)

Kuzmina, Natalia; Izvekova, Yulia N.

2016-04-01

Some analytical solutions are found for the problem of three-dimensional instability of a weak geostrophic flow with linear velocity shear taking into account vertical diffusion of buoyancy. The analysis is based on the potential vorticity equation in a long-wave approximation when the horizontal scale of disturbances is taken much larger than the local baroclinic radius Rossby. It is hypothesized that the solutions found can be applied to describe stable and unstable disturbances of planetary scale with respect, especially, to the Arctic basin where weak baroclinic fronts with typical temporal variability period of the order of several years or more are observed and the beta-effect is negligible. Stable (decreasing with time) solutions describe disturbances that, in contrast to the Rossby waves, can propagate both to the west and east depending on the sign of linear shear of geostrophic velocity. The unstable (growing with time) solutions are applied to describe large-scale intrusions at baroclinic fronts under stable-stable thermohaline stratification observed in the upper layer of the Polar Deep Water in the Eurasian basin. The proposed description of intrusive layering can be considered as a possible alternative to the mechanism of interleaving due to the differential mixing (Merryfield, 2002; Kuzmina et al., 2011). References Kuzmina N., Rudels B., Zhurbas V., Stipa T. On the structure and dynamical features of intrusive layering in the Eurasian Basin in the Arctic Ocean. J. Geophys. Res., 2011, 116, C00D11, doi:10.1029/2010JC006920. Merryfield W. J. Intrusions in double-diffusively stable Arctic Waters: Evidence for differential mixing? J. Phys. Oceanogr., 2002, 32, 1452-1439.

Temporal logics meet telerobotics

NASA Technical Reports Server (NTRS)

Rutten, Eric; Marce, Lionel

1989-01-01

The specificity of telerobotics being the presence of a human operator, decision assistance tools are necessary for the operator, especially in hostile environments. In order to reduce execution hazards due to a degraded ability for quick and efficient recovery of unexpected dangerous situations, it is of importance to have the opportunity, amongst others, to simulate the possible consequences of a plan before its actual execution, in order to detect these problematic situations. Hence the idea of providing the operator with a simulator enabling him to verify the temporal and logical coherence of his plans. Therefore, the power of logical formalisms is used for representation and deduction purposes. Starting from the class of situations that are represented, a STRIPS (the STanford Research Institute Problem Solver)-like formalism and its underlying logic are adapted to the simulation of plans of actions in time. The choice of a temporal logic enables to build a world representation, on which the effects of plans, grouping actions into control structures, will be transcribed by the simulation, resulting in a verdict and information about the plan's coherence.

Correlated full-field and pointwise temporally resolved measurements of thermomechanical stress inside an operating power transistor

NASA Astrophysics Data System (ADS)

Borza, Dan N.; Gautrelet, Christophe

2015-01-01

The paper describes a measurement system based on time-resolved speckle interferometry, able to record long series of thermally induced full-field deformation maps of die and wire bonds inside an operating power transistor. The origin of the deformation is the transistor heating during its normal operation. The full-field results consist in completely unwrapped deformation maps for out-of-plane displacements greater than 14 μm, with nanometer resolution, in presence of discontinuities due to structural and material inhomogeneity. These measurements are synchronized with the measurement of heatsink temperature and of base-emitter junction temperature, so as to provide data related to several interacting physical parameters. The temporal histories of the displacement are also accessible for any point. They are correlated with the thermal and electrical time series. Mechanical full-field curvatures may also be estimated, making these measurements useful for inspecting physical origins of thermomechanical stresses and for interacting with numerical models used in reliability-related studies.

Temporal compression in episodic memory for real-life events.

PubMed

Jeunehomme, Olivier; Folville, Adrien; Stawarczyk, David; Van der Linden, Martial; D'Argembeau, Arnaud

2018-07-01

Remembering an event typically takes less time than experiencing it, suggesting that episodic memory represents past experience in a temporally compressed way. Little is known, however, about how the continuous flow of real-life events is summarised in memory. Here we investigated the nature and determinants of temporal compression by directly comparing memory contents with the objective timing of events as measured by a wearable camera. We found that episodic memories consist of a succession of moments of prior experience that represent events with varying compression rates, such that the density of retrieved information is modulated by goal processing and perceptual changes. Furthermore, the results showed that temporal compression rates remain relatively stable over one week and increase after a one-month delay, particularly for goal-related events. These data shed new light on temporal compression in episodic memory and suggest that compression rates are adaptively modulated to maintain current goal-relevant information.

Prospects for Ultra-Stable Timekeeping with Sealed Vacuum Operation in Multi-Pole Linear Ion Trap Standards

NASA Technical Reports Server (NTRS)

Burt, Eric A.; Tjoelker, R. L.

2007-01-01

A recent long-term comparison between the compensated multi-pole Linear Ion Trap Standard (LITS) and the laser-cooled primary standards via GPS carrier phase time transfer showed a deviation of less than 2.7x10(exp -17)/day. A subsequent evaluation of potential drift contributors in the LITS showed that the leading candidates are fluctuations in background gases and the neon buffer gas. The current vacuum system employs a "flow-through" turbomolecular pump and a diaphragm fore pump. Here we consider the viability of a "sealed" vacuum system pumped by a non-evaporable getter for long-term ultra-stable clock operation. Initial tests suggests that both further stability improvement and longer mean-time-between-maintenance can be achieved using this approach

Spatial-temporal changes in Andean plateau climate and elevation from stable isotopes of mammal teeth

NASA Astrophysics Data System (ADS)

Bershaw, John; Garzione, Carmala N.; Higgins, Pennilyn; MacFadden, Bruce J.; Anaya, Frederico; Alvarenga, Herculano

2010-01-01

Paleoelevation constraints from fossil leaf physiognomy and stable isotopes of sedimentary carbonate suggest that significant surface uplift of the northern Andean plateau, on the order of 2.5 ± 1 km, occurred between ˜ 10.3 and 6.4 Ma. Independent spatial and temporal constraints on paleoelevation and paleoclimate of both the northern and southern plateau are important for understanding the distribution of rapid surface uplift and its relation to climate evolution across the plateau. This study focuses on teeth from modern and extinct mammal taxa (including notoungulates, pyrotheres, and litopterns) spanning ˜ 29 Ma to present, collected from the Altiplano and Eastern Cordillera of Bolivia (16.2°S to 21.4°S), and lowland Brazil. Tooth enamel of large, water-dependent mammals preserves a record of surface water isotopes and the type of plants that animals ingested while their teeth were mineralizing. Previous studies have shown that the δ18O of modern precipitation and surface waters decrease systematically with increasing elevations across the central Andes. Our results from high elevation sites between 3600 and 4100 m show substantially more positive δ18O values for late Oligocene tooth samples compared to < 10 Ma tooth δ18O values. Late Oligocene teeth collected from low elevation sites in southeast Brazil show δ18O values similar (within 2‰) to contemporaneous teeth collected at high elevation in the Eastern Cordillera. This affirms that the Andean plateau was at a very low elevation during the late Oligocene. Late Oligocene teeth from the northern Eastern Cordillera also yield consistent δ13C values of about - 9‰, indicating that the environment was semi-arid at that time. Latitudinal gradients in δ18O values of late Miocene to Pliocene fossil teeth are similar to modern values for large mammals, suggesting that by ˜ 8 Ma in the northern Altiplano and by ˜ 3.6 Ma in the southern Altiplano, both regions had reached high elevation and

Interannual Variation in Stable Carbon and Nitrogen Isotope Biogeochemistry of the Mattaponi River, Virginia

EPA Science Inventory

This manuscript addresses the difficult issue of identifying the origin of particulate organic matter (POM) in estuaries . . . The objectives of this study were to quantify spatial and temporal variability of the C and N stable isotope composition of suspended POM, and to identif...

Pre- and post-operative Wisconsin card sorting test performance in patients with temporal lobe epilepsy due to hippocampal sclerosis

PubMed Central

Tisser, Luciana; Palmini, Andre; Paglioli, Eliseu; Portuguez, Mirna; Azambuja, Ney; da Costa, Jaderson Costa; Paglioli, Eduardo; Torres, Carolina; Martinez, Jose Victor

2007-01-01

Patients with temporal lobe epilepsy due to hippocampal sclerosis (TLE/HS) have a distinct neuropsychological profile, but there is still debate on whether executive dysfunction is part of this profile and also whether temporal lobe surgery can modify this dysfunction. Objective To study the presence and reversibility of executive dysfunction in patients with unilateral TLE/HS. Methods Twenty-five patients with refractory seizures due to TLE/HS underwent presurgical evaluation which included the application of the Wiconsin Card Sorting Test (WCST). Nineteen were re-evaluated in follow up, at least 6 months after selective amygdalo-hippocampectomy (SAH). Twenty-two control subjects matched for age and education also performed the WCST. Results Sixteen of the 25 patients (64%) completed fewer than four categories in the WCST whereas only 4 of the 22 controls (18%) did not complete at least four categories (p<0.005). In addition, the performance of the patients involved significantly more perseverative responses and errors compared to controls. The patient group demonstrated significant post-operative improvement in many measures of the WCST following SAH. Conclusions These findings support the presence of executive dysfunction in patients with TLE/HS and suggest that such dysfunction can be partially reversed by selective resection of epileptogenic mesial temporal structures. PMID:29213385

Finding Mutual Exclusion Invariants in Temporal Planning Domains

NASA Technical Reports Server (NTRS)

Bernardini, Sara; Smith, David E.

2011-01-01

We present a technique for automatically extracting temporal mutual exclusion invariants from PDDL2.2 planning instances. We first identify a set of invariant candidates by inspecting the domain and then check these candidates against properties that assure invariance. If these properties are violated, we show that it is sometimes possible to refine a candidate by adding additional propositions and turn it into a real invariant. Our technique builds on other approaches to invariant synthesis presented in the literature, but departs from their limited focus on instantaneous discrete actions by addressing temporal and numeric domains. To deal with time, we formulate invariance conditions that account for both the entire structure of the operators (including the conditions, rather than just the effects) and the possible interactions between operators. As a result, we construct a technique that is not only capable of identifying invariants for temporal domains, but is also able to find a broader set of invariants for non-temporal domains than the previous techniques.

Electrophysiological Features of Single Store-Operated Calcium Channels in HEK S4 Cell Line with Stable STIM1 Protein Knockdown.

PubMed

Shalygin, A V; Vigont, V A; Glushankova, L N; Zimina, O A; Kolesnikov, D O; Skopin, A Yu; Kaznacheeva, E V

2017-07-01

An important role in intracellular calcium signaling is played by store-operated channels activated by STIM proteins, calcium sensors of the endoplasmic reticulum. In stable STIM1 knockdown HEK S4 cells, single channels activated by depletion of intracellular calcium stores were detected by cell-attached patch-clamp technique and their electrophysiological parameters were described. Comparison of the properties of single channels in HEK293 and HEK S4 cells revealed no significant differences in their current-voltage curves, while regulation of store-operated calcium channels in these cell lines depended on the level of STIM1 expression. We can conclude that electrophysiological peculiarities of store-regulated calcium entry observed in different cells can be explained by differences in STIM1 expression.

Changes in multifractal properties for stable angina pectoris

NASA Astrophysics Data System (ADS)

Knežević, Andrea; Martinis, Mladen; Krstačić, Goran; Vargović, Emil

2005-12-01

The multifractal approach has been applied to temporal fluctuations of heartbeat (RR) intervals, measured in various regimes of physical activity (ergometric data), taken from healthy subjects and those having stable angina pectoris (SAP). The problem we address here is whether SAP changes multifractality observed in healthy subjects. The G-moment method is used to analyse the multifractal spectrum. It is observed that both sets of data characterize multifractality, but a different trend in multifractal behaviour is found for SAP disease, under pronounced physical activity.

Highly Stable Operation of Lithium Metal Batteries Enabled by the Formation of a Transient High Concentration Electrolyte Layer

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

Zheng, Jianming; Yan, Pengfei; Mei, Donghai

2016-02-08

Lithium (Li) metal has been extensively investigated as an anode for rechargeable battery applications due to its ultrahigh specific capacity and the lowest redox potential. However, significant challenges including dendrite growth and low Coulombic efficiency are still hindering the practical applications of rechargeable Li metal batteries. Here, we demonstrate that long-term cycling of Li metal batteries can be realized by the formation of a transient high concentration electrolyte layer near the surface of Li metal anode during high rate discharge process. The highly concentrated Li+ ions in this transient layer will immediately solvate with the available solvent molecules and facilitatemore » the formation of a stable and flexible SEI layer composed of a poly(ethylene carbonate) framework integrated with other organic/inorganic lithium salts. This SEI layer largely suppresses the corrosion of Li metal anode by free organic solvents and enables the long-term operation of Li metal batteries. The fundamental findings in this work provide a new direction for the development and operation of Li metal batteries that could be operated at high current densities for a wide range of applications.« less

Research on target tracking algorithm based on spatio-temporal context

NASA Astrophysics Data System (ADS)

Li, Baiping; Xu, Sanmei; Kang, Hongjuan

2017-07-01

In this paper, a novel target tracking algorithm based on spatio-temporal context is proposed. During the tracking process, the camera shaking or occlusion may lead to the failure of tracking. The proposed algorithm can solve this problem effectively. The method use the spatio-temporal context algorithm as the main research object. We get the first frame's target region via mouse. Then the spatio-temporal context algorithm is used to get the tracking targets of the sequence of frames. During this process a similarity measure function based on perceptual hash algorithm is used to judge the tracking results. If tracking failed, reset the initial value of Mean Shift algorithm for the subsequent target tracking. Experiment results show that the proposed algorithm can achieve real-time and stable tracking when camera shaking or target occlusion.

[Temporal rotation skin flap combined with cartilage plasty for correcting cryptotia].

PubMed

Li, Gaofeng; Luo, Tao; Ding, Wei; Ouyang, Huawei; Liu, Wanli; Tan, Jun

2014-01-01

To explore the therapeutic effect of the temporal rotation flap combined with cartilage plasty for cryptotia correction. From January 2009 to June 2012, 8 cases with cryptotia (10 ears) were treated. After complete dissection of the cartilage adhesion, the cartilage was reshaped by suture to restore its appearance. Then the temporal triangular rotation flap was transferred to cover the wound. No hematoma, infection or flap necrosis happened. The follow-up period ranged from 3 months to 1 year, with an average of (6.88 +/- 2.85) months. The ear appearance kept stable with no recurrence and inconspicuous scar. Satisfactory result was achieved. Temporal rotation flap combined with cartilage plasty is a good option for correction of mild or moderate cryptotia.

Verbal Dominant Memory Impairment and Low Risk for Post-operative Memory Worsening in Both Left and Right Temporal Lobe Epilepsy Associated with Hippocampal Sclerosis.

PubMed

Khalil, Amr Farid; Iwasaki, Masaki; Nishio, Yoshiyuki; Jin, Kazutaka; Nakasato, Nobukazu; Tominaga, Teiji

2016-11-15

Post-operative memory changes after temporal lobe surgery have been established mainly by group analysis of cognitive outcome. This study investigated individual patient-based memory outcome in surgically-treated patients with mesial temporal lobe epilepsy (TLE). This study included 84 consecutive patients with intractable TLE caused by unilateral hippocampal sclerosis (HS) who underwent epilepsy surgery (47 females, 41 left [Lt] TLE). Memory functions were evaluated with the Wechsler Memory Scale-Revised before and at 1 year after surgery. Pre-operative memory function was classified into three patterns: verbal dominant memory impairment (Verb-D), visual dominant impairment (Vis-D), and no material-specific impairment. Post-operative changes in verbal and visual memory indices were classified into meaningful improvement, worsening, or no significant changes. Pre-operative patterns and post-operative changes in verbal and visual memory function were compared between the Lt and right (Rt) TLE groups. Pre-operatively, Verb-D was the most common type of impairment in both the Lt and Rt TLE groups (65.9 and 48.8%), and verbal memory indices were lower than visual memory indices, especially in the Lt compared with Rt TLE group. Vis-D was observed only in 11.6% of Rt and 7.3% of Lt TLE patients. Post-operatively, meaningful improvement of memory indices was observed in 23.3-36.6% of the patients, and the memory improvement was equivalent between Lt and Rt TLE groups and between verbal and visual materials. In conclusion, Verb-D is most commonly observed in patients with both the Lt and Rt TLE associated with HS. Hippocampectomy can improve memory indices in such patients regardless of the side of surgery and the function impaired.

Spatial and Temporal Variations in Stable Carbon (δ13C) and Nitrogen (δ15N) Isotopic Composition of Symbiotic Scleractinian Corals

PubMed Central

Nahon, Sarah; Richoux, Nicole B.; Kolasinski, Joanna; Desmalades, Martin; Ferrier Pages, Christine; Lecellier, Gael; Planes, Serge; Berteaux Lecellier, Véronique

2013-01-01

Tropical scleractinian corals are considered autotrophic as they rely mainly on photosynthesis-derived nutrients transferred from their photosymbionts. Corals are also able to capture and ingest suspended particulate organic matter, so heterotrophy can be an important supplementary trophic pathway to optimize coral fitness. The aim of this in situ study was to elucidate the trophic status of 10 coral species under contrasted environmental conditions in a French Polynesian lagoon. Carbon (δ13C) and nitrogen (δ15N) isotopic compositions of coral host tissues and photosymbionts were determined at 3 different fringing reefs during wet and dry seasons. Our results highlighted spatial variability in stable isotopic compositions of both coral host tissues and photosymbionts. Samples from the site with higher level of suspended particulate matter were 13C-depleted and 15N-enriched relative to corals and photosymbionts from less turbid sites. However, differences in both δ13C and δ15N between coral host tissues and their photosymbionts (Δhost-photosymbionts 13C and Δhost-photosymbionts 15N) were small (0.27 ± 0.76‰ and 1.40 ± 0.90‰, respectively) and similar at all sites, thus indicating no general increases in the heterotrophic pathway. Depleted δ13C and enriched δ15N values of coral host tissues measured at the most turbid site were explained by changes in isotopic composition of the inorganic nutrients taken up by photosymbionts and also by changes in rate of isotopic fractionation with environmental conditions. Our results also highlighted a lack of significant temporal variations in δ13C and δ15N values of coral host and photosymbiont tissues and in Δhost-photosymbionts 13C and Δhost-photosymbionts 15N values. This temporal stability indicated that corals remained principally autotrophic even during the wet season when photosymbiont densities were lower and the concentrations of phytoplankton were higher. Increased coral heterotrophy with higher food

Stable operation during pilot-scale anaerobic digestion of nutrient-supplemented maize/sugar beet silage.

PubMed

Nges, Ivo Achu; Björn, Annika; Björnsson, Lovisa

2012-08-01

Biogas production from maize/sugar beet silage was studied under mesophilic conditions in a continuous stirred tank reactor pilot-scale process. While energy crop mono-digestion is often performed with very long hydraulic retention times (HRTs), the present study demonstrated an efficient process operating with a 50-day HRT and a corrected total solids (TS(corr)) based organic loading rate of 3.4 kg/m(3)d. The good performance was attributed to supplementation with both macro- and micronutrients and was evidenced by good methane yields (318 m(3)/ton TS(corr)), which were comparable to laboratory maximum expected yields, plus low total volatile fatty acid concentrations (<0.8 g/L). A viscoplastic and thixotropic digester fluid behaviour was observed, and the viscosity problems common in crop mono-digestion were not seen in this study. The effluent also complied with Swedish certification standards for bio-fertilizer for farmland application. Nutrient addition thus rendered a stable biogas process, while the effluent was a good quality bio-fertilizer. Copyright © 2012 Elsevier Ltd. All rights reserved.

Spatial and temporal variability of runoff and streamflow generation within and among headwater catchments: a combined hydrometric and stable isotope approach

NASA Astrophysics Data System (ADS)

Singh, N. K.; Emanuel, R. E.; McGlynn, B. L.

2012-12-01

The combined influence of topography and vegetation on runoff generation and streamflow in headwater catchments remains unclear. We aim to understand how spatial, hydrological and climate variables affect runoff generation and streamflow at hillslope and watershed scales at the Coweeta Hydrologic Laboratory (CHL) in the southern Appalachian Mountains by analyzing stable isotopes of hydrogen (2H) and oxygen (18O) coupled with measurements of hydrological variables (stream discharge, soil moisture, shallow groundwater) and landscape variables (upslope accumulated area, vegetation density slope, and aspect). We investigated four small catchments, two of which contained broadleaf deciduous vegetation and two of which contained evergreen coniferous vegetation. Beginning in June 2011, we collected monthly water samples at 25 m intervals along each stream, monthly samples from 24 shallow groundwater wells, and weekly to monthly samples from 10 rain gauges distributed across CHL. Water samples were analyzed for 2H and 18O using cavity ring-down spectroscopy. During the same time period we recorded shallow groundwater stage at 30 min intervals from each well, and beginning in fall 2011 we collected volumetric soil moisture data at 30 min intervals from multiple depths at 16 landscape positions. Results show high spatial and temporal variability in δ2H and δ18O within and among streams, but in general we found isotopic enrichment with increasing contributing area along each stream. We used a combination of hydrometric observations and geospatial analyses to understand why stream isotope patterns varied during the year and among watersheds, and we used complementary measurements of δ2H and δ18O from other pools within the watersheds to understand the movement and mixing of precipitation that precedes runoff formation. This combination of high resolution stable isotope data and hydrometric observations facilitates a clearer understanding of spatial controls on streamflow

Closed-Cycle, Frequency-Stable CO2 Laser Technology

NASA Technical Reports Server (NTRS)

Batten, Carmen E. (Editor); Miller, Irvin M. (Editor); Wood, George M., Jr. (Editor); Willetts, David V. (Editor)

1987-01-01

These proceedings contain a collection of papers and comments presented at a workshop on technology associated with long-duration closed-cycle operation of frequency-stable, pulsed carbon dioxide lasers. This workshop was held at the NASA Langley Research Center June 10 to 12, 1986. The workshop, jointly sponsored by the National Aeronautics and Space Administration (NASA) and the Royal Signals and Radar Establishment (RSRE), was attended by 63 engineers and scientists from the United States and the United Kingdom. During the 2 1/2 days of the workshop, a number of issues relating to obtaining frequency-stable operation and to the catalytic control of laser gas chemistry were discussed, and specific recommendations concerning future activities were drafted.

Cubic map algebra functions for spatio-temporal analysis

USGS Publications Warehouse

Mennis, J.; Viger, R.; Tomlin, C.D.

2005-01-01

We propose an extension of map algebra to three dimensions for spatio-temporal data handling. This approach yields a new class of map algebra functions that we call "cube functions." Whereas conventional map algebra functions operate on data layers representing two-dimensional space, cube functions operate on data cubes representing two-dimensional space over a third-dimensional period of time. We describe the prototype implementation of a spatio-temporal data structure and selected cube function versions of conventional local, focal, and zonal map algebra functions. The utility of cube functions is demonstrated through a case study analyzing the spatio-temporal variability of remotely sensed, southeastern U.S. vegetation character over various land covers and during different El Nin??o/Southern Oscillation (ENSO) phases. Like conventional map algebra, the application of cube functions may demand significant data preprocessing when integrating diverse data sets, and are subject to limitations related to data storage and algorithm performance. Solutions to these issues include extending data compression and computing strategies for calculations on very large data volumes to spatio-temporal data handling.

Temporal Stability and Convergent Validity of the Behavior Assessment System for Children.

ERIC Educational Resources Information Center

Merydith, Scott P.

2001-01-01

Assesses the temporal stability and convergent validity of the Behavioral Assessment System for Children (BASC). Teachers and parents rated kindergarten and first-grade students using BASC. Teachers were more stable in rating children's externalizing behaviors and attention problems. Discusses results in terms of the accuracy of information…

Estimates of spatial and temporal variation of energy crops biomass yields in the US

NASA Astrophysics Data System (ADS)

Song, Y.; Jain, A. K.; Landuyt, W.; Kheshgi, H. S.

2013-12-01

Perennial grasses, such as switchgrass (Panicum viragatum) and Miscanthus (Miscanthus x giganteus) have been identified for potential use as biomass feedstocks in the US. Current research on perennial grass biomass production has been evaluated on small-scale plots. However, the extent to which this potential can be realized at a landscape-scale will depend on the biophysical potential to grow these grasses with minimum possible amount of land that needs to be diverted from food to fuel production. To assess this potential three questions about the biomass yield for these grasses need to be answered: (1) how the yields for different grasses are varied spatially and temporally across the US; (2) whether the yields are temporally stable or not; and (3) how the spatial and temporal trends in yields of these perennial grasses are controlled by limiting factors, including soil type, water availability, climate, and crop varieties. To answer these questions, the growth processes of the perennial grasses are implemented into a coupled biophysical, physiological and biogeochemical model (ISAM). The model has been applied to quantitatively investigate the spatial and temporal trends in biomass yields for over the period 1980 -2010 in the US. The bioenergy grasses considered in this study include Miscanthus, Cave-in-Rock switchgrass and Alamo switchgrass. The effects of climate, soil and topography on the spatial and temporal trends of biomass yields are quantitatively analyzed using principal component analysis and GIS based geographically weighted regression. The spatial temporal trend results are evaluated further to classify each part of the US into four homogeneous potential yield zones: high and stable yield zone (HS), high but unstable yield zone (HU), low and stable yield zone (LS) and low but unstable yield zone (LU). Our preliminary results indicate that the yields for perennial grasses among different zones are strongly related to the different controlling factors

Temporal stability of Escherichia coli concentration patterns in two irrigation ponds in Maryland

USDA-ARS?s Scientific Manuscript database

Fecal contamination of water sources is an important water quality issue for agricultural irrigation ponds. Escherichia coli is a common microbial indicator used to evaluate recreational and irrigation water quality. We hypothesized that there is a temporally stable pattern of E.coli concentrations ...

Using Advanced Tensiometers to Monitor Temporal Variations in Pore Pressure

NASA Astrophysics Data System (ADS)

Nichols, R. L.; Young, M. H.; Dixon, K. L.; Rossabi, J.; Hyde, W. K.; Holmes-Burns, H.

2002-12-01

The Savannah River Site has installed a comprehensive vadose zone monitoring system (VZMS) at it's low level radioactive waste disposal facility to collect the necessary information to calculate contaminant flux. The VZMS includes water content reflectometers, suction lysimeters, advanced tensiometers (ATs), water flux meters, access ports for neutron probes, and a tipping bucket rain gauge. Forty one ATs were installed from 1999 to 2001 at depths ranging from 2 to 60 feet and have been operated continuously. The installation depths were based on a hydrostatigraphic model developed from core logs, cone penetrometer logs, moisture content profiles, water retention curves model that were obtained during the phased installation of the VZMS. An AT consists of a porous cup installed at a prescribed depth with casing back to the surface and a pressure transducer that is lowered into the casing and connects with the porous cup. The pressure transducer transmits it's signal to a datalogger where the data is stored for future retrieval using a cellular phone communications package. Results from the 2 year operating period show that the AT calibrations are stable and t ATs are capable of extended monitoring of pore pressures in the 0 to 300 cm H2 O range. The ATs had sufficient resolution to detect the naturally occurring fluctuations in pore pressure (1 to 100 cm H2 O over 1 to 72 hours) that resulted from infiltration events at the site. The stable performance of the ATs combined with their ability to detect naturally occurring fluctuations in pore pressure make the ATs a useful tool in measuring temporal pore pressure variations for use in calibrating numerical models of fluid flow in variably saturated porous media.

Temporal evolution of stable water isotopologues in cloud droplets in a hill cap cloud in central Europe (HCCT-2010)

USGS Publications Warehouse

Spiegel, J.K.; Aemisegger, F.; Scholl, M.; Wienhold, F.G.; Collett, J.L.; Lee, T.; van Pinxteren, D.; Mertes, S.; Tilgner, A.; Herrmann, H.; Werner, Roland A.; Buchmann, N.; Eugster, W.

2012-01-01

In this work, we present the first study resolving the temporal evolution of δ2H and δ18O values in cloud droplets during 13 different cloud events. The cloud events were probed on a 937 m high mountain chain in Germany in the framework of the Hill Cap Cloud Thuringia 2010 campaign (HCCT-2010) in September and October 2010. The δ values of cloud droplets ranged from −77‰ to −15‰ (δ2H) and from −12.1‰ to −3.9‰ (δ18O) over the whole campaign. The cloud water line of the measured δ values was δ2H=7.8×δ18O+13×10−3, which is of similar slope, but with higher deuterium excess than other Central European Meteoric Water Lines. Decreasing δ values in the course of the campaign agree with seasonal trends observed in rain in central Europe. The deuterium excess was higher in clouds developing after recent precipitation revealing episodes of regional moisture recycling. The variations in δ values during one cloud event could either result from changes in meteorological conditions during condensation or from variations in the δ values of the water vapor feeding the cloud. To test which of both aspects dominated during the investigated cloud events, we modeled the variation in δ values in cloud water using a closed box model. We could show that the variation in δ values of two cloud events was mainly due to changes in local temperature conditions. For the other eleven cloud events, the variation was most likely caused by changes in the isotopic composition of the advected and entrained vapor. Frontal passages during two of the latter cloud events led to the strongest temporal changes in both δ2H (≈ 6‰ per hour) and δ18O (≈ 0.6‰ per hour). Moreover, a detailed trajectory analysis for the two longest cloud events revealed that variations in the entrained vapor were most likely related to rain out or changes in relative humidity and temperature at the moisture source region or both. This study illustrates the sensitivity of stable isotope

An operational ensemble prediction system for catchment rainfall over eastern Africa spanning multiple temporal and spatial scales

NASA Astrophysics Data System (ADS)

Riddle, E. E.; Hopson, T. M.; Gebremichael, M.; Boehnert, J.; Broman, D.; Sampson, K. M.; Rostkier-Edelstein, D.; Collins, D. C.; Harshadeep, N. R.; Burke, E.; Havens, K.

2017-12-01

While it is not yet certain how precipitation patterns will change over Africa in the future, it is clear that effectively managing the available water resources is going to be crucial in order to mitigate the effects of water shortages and floods that are likely to occur in a changing climate. One component of effective water management is the availability of state-of-the-art and easy to use rainfall forecasts across multiple spatial and temporal scales. We present a web-based system for displaying and disseminating ensemble forecast and observed precipitation data over central and eastern Africa. The system provides multi-model rainfall forecasts integrated to relevant hydrological catchments for timescales ranging from one day to three months. A zoom-in features is available to access high resolution forecasts for small-scale catchments. Time series plots and data downloads with forecasts, recent rainfall observations and climatological data are available by clicking on individual catchments. The forecasts are calibrated using a quantile regression technique and an optimal multi-model forecast is provided at each timescale. The forecast skill at the various spatial and temporal scales will discussed, as will current applications of this tool for managing water resources in Sudan and optimizing hydropower operations in Ethiopia and Tanzania.

How Stable Is Stable?

ERIC Educational Resources Information Center

Baehr, Marie

1994-01-01

Provides a problem where students are asked to find the point at which a soda can floating in some liquid changes its equilibrium between stable and unstable as the soda is removed from the can. Requires use of Newton's first law, center of mass, Archimedes' principle, stable and unstable equilibrium, and buoyant force position. (MVL)

Temporal context processing within hippocampal subfields.

PubMed

Wang, Fang; Diana, Rachel A

2016-07-01

The episodic memory system can differentiate similar events based on the temporal information associated with the events. Temporal context, which is at least partially determined by the events that precede or follow the critical event, may be a cue to differentiate events. The purpose of the present study is to investigate whether the hippocampal dentate gyrus (DG)/CA3 and CA1 subfields are sensitive to changes in temporal context and, if so, whether the subregions show a linear or threshold-like response to similar temporal contexts. Participants incidentally encoded a series of object picture triplets and 20 of them were included in final analyses. The third picture in each triplet was operationally defined as the target and the first two pictures served as temporal context for the target picture. Each target picture was presented twice with temporal context manipulated to be either repeated, high similarity, low similarity, or new on the second presentation. We extracted beta parameters for the repeated target as a function of the type of temporal context. We expected to see repetition suppression, a reduction in the beta values, in response to repetition of the target. If temporal context information is included in the representation of the target within a given region, this repetition suppression should be greater for target images that were preceded by their original context than for target images preceded by a new context. Neuroimaging results showed that CA1, but not DG/CA3, modifies the target's representation based on its temporal context. Right CA1 did not distinguish high similarity temporal context from repeated context but did distinguish low similarity temporal context from repeated context. These results indicate that CA1 is sensitive to temporal context and suggest that it does not differentiate between a substantially similar temporal context and an identical temporal context. In contrast, DG/CA3 does not appear to process temporal context as

High-resolution space-time characterization of convective rain cells: implications on spatial aggregation and temporal sampling operated by coarser resolution instruments

NASA Astrophysics Data System (ADS)

Marra, Francesco; Morin, Efrat

2017-04-01

Forecasting the occurrence of flash floods and debris flows is fundamental to save lives and protect infrastructures and properties. These natural hazards are generated by high-intensity convective storms, on space-time scales that cannot be properly monitored by conventional instrumentation. Consequently, a number of early-warning systems are nowadays based on remote sensing precipitation observations, e.g. from weather radars or satellites, that proved effective in a wide range of situations. However, the uncertainty affecting rainfall estimates represents an important issue undermining the operational use of early-warning systems. The uncertainty related to remote sensing estimates results from (a) an instrumental component, intrinsic of the measurement operation, and (b) a discretization component, caused by the discretization of the continuous rainfall process. Improved understanding on these sources of uncertainty will provide crucial information to modelers and decision makers. This study aims at advancing knowledge on the (b) discretization component. To do so, we take advantage of an extremely-high resolution X-Band weather radar (60 m, 1 min) recently installed in the Eastern Mediterranean. The instrument monitors a semiarid to arid transition area also covered by an accurate C-Band weather radar and by a relatively sparse rain gauge network ( 1 gauge/ 450 km2). Radar quantitative precipitation estimation includes corrections reducing the errors due to ground echoes, orographic beam blockage and attenuation of the signal in heavy rain. Intense, convection-rich, flooding events recently occurred in the area serve as study cases. We (i) describe with very high detail the spatiotemporal characteristics of the convective cores, and (ii) quantify the uncertainty due to spatial aggregation (spatial discretization) and temporal sampling (temporal discretization) operated by coarser resolution remote sensing instruments. We show that instantaneous rain intensity

Strategies for Global Optimization of Temporal Preferences

NASA Technical Reports Server (NTRS)

Morris, Paul; Morris, Robert; Khatib, Lina; Ramakrishnan, Sailesh

2004-01-01

A temporal reasoning problem can often be naturally characterized as a collection of constraints with associated local preferences for times that make up the admissible values for those constraints. Globally preferred solutions to such problems emerge as a result of well-defined operations that compose and order temporal assignments. The overall objective of this work is a characterization of different notions of global preference, and to identify tractable sub-classes of temporal reasoning problems incorporating these notions. This paper extends previous results by refining the class of useful notions of global temporal preference that are associated with problems that admit of tractable solution techniques. This paper also answers the hitherto open question of whether problems that seek solutions that are globally preferred from a Utilitarian criterion for global preference can be found tractably.

Sulfur poisoning of Ni/Gadolinium-doped ceria anodes: A long-term study outlining stable solid oxide fuel cell operation

NASA Astrophysics Data System (ADS)

Riegraf, Matthias; Zekri, Atef; Knipper, Martin; Costa, Rémi; Schiller, Günter; Friedrich, K. Andreas

2018-03-01

This work presents an analysis of the long-term behavior of nickel/gadolinium-doped ceria (CGO) anode-based solid oxide fuel cells (SOFC) under sulfur poisoning conditions. A parameter study of sulfur-induced irreversible long-term degradation of commercial, high-performance single cells was carried out at 900 °C for different H2/N2/H2S fuel gas atmospheres, current densities and Ni/CGO anodes. The poisoning periods of the cells varied from 200 to 1500 h. The possibility of stable long-term Ni/CGO anode operation under sulfur exposure is established and the critical operating regime is outlined. Depending on the operating conditions, two degradation phenomena can be observed. Small degradation of the ohmic resistance was witnessed for sulfur exposure times of approximately 1000 h. Moreover, degradation of the anode charge transfer resistance was observed to be triggered by the combination of a small anodic potential step and high sulfur coverage on Ni. The microstructural evolution of altered Ni/CGO anodes was examined post-mortem by means of SEM and FIB/SEM, and is correlated to the anode performance degradation under critical operating conditions, establishing Ni depletion, porosity increase and a tripe phase boundary density decrease in the anode functional layer. It is shown that short-term sulfur poisoning behavior can be used to assess long-term stability.

A mobile and self-sufficient lab for high frequency measurements of stable water isotopes and chemistry of multiple water sources

NASA Astrophysics Data System (ADS)

Windhorst, David; Kraft, Philipp; Holly, Hartmut; Sahraei, Amir; Breuer, Lutz

2017-04-01

Technical advances over the last years have made instruments for stable water isotope and water chemistry measurements smaller, more durable and energy efficient. It is nowadays feasible to deploy such instruments in situ during field campaigns. Coupled to an automated sample delivery system, high temporal resolution online measurements of various sources are within the bounds of economic and technical possibility. However, the day to day operation of such equipment still requires either a lot of man power and infrastructure or the implementation of a quasi-self-sufficient system. The challenge remains on how to facilitate and remotely operate such a system. We present the design and implementation of the Water Analysis Trailer for Environmental Research (WATER), an autonomous platform consisting of instruments for stable water isotope and water chemistry analysis. The system takes and measures samples in high temporal resolution (<15 min) of up to 12 sources. To ensure an unmanned operation of up to one week several issues need to be addressed. The essential topics are: - self-sufficient power supply, - automated sample delivery and preparation, and - autonomous measurements and management interfacing all instruments. In addition to the basic requirements we implemented: - communication of all system states, alarm messages and measurement results to an internal as well as an external database via cellular telemetry, - automated storage of up to 300 frozen reference samples (100 mL, stored at -18°C), - climate control for temperature sensitive equipment (±1°C), - a local and remote (up to 20 km using radio telemetry) sensor network (i.e. to record states of the hydrological system and climate and soil conditions), also suitable to trigger specific measurements - automatic fire suppression and security system. The initial instrumentation includes a UV spectrometer (ProPs, Trios GmBH, Germany) to measure NO3-, COD, TOC and total suspended sediments, multiparameter

Behavioral Changes Predicting Temporal Changes in Perceived Popular Status

PubMed Central

Bowker, Julie C.; Rubin, Kenneth H.; Buskirk-Cohen, Alison; Rose-Krasnor, Linda; Booth-LaForce, Cathryn

2009-01-01

The primary objectives of this investigation were to determine the extent to which young adolescents are stable in high perceived popular status across the middle school transition and to examine whether changes in social behaviors predict the stability, gain, and loss of perceived popular status after the transition. The sample included 672 young adolescents (323 boys) who completed peer-nomination assessments of social behavior and perceived popularity at the end of elementary school (5th grade) and the beginning of middle school (6th grade). Findings indicated that 62 percent of perceived popular adolescents remained stable in their high popular status across the middle school transition. Multinomial logistic regression analyses revealed that a combination of aggression and arrogance/conceit was associated with stable and newly-gained perceived popular status after the middle school transition. Taken together, findings highlight the significance of contextual and temporal changes in adolescents’ perceived popular status. PMID:20209113

Spatio-Temporal Evolution and Scaling Properties of Human Settlements (Invited)

NASA Astrophysics Data System (ADS)

Small, C.; Milesi, C.; Elvidge, C.; Baugh, K.; Henebry, G. M.; Nghiem, S. V.

2013-12-01

Growth and evolution of cities and smaller settlements is usually studied in the context of population and other socioeconomic variables. While this is logical in the sense that settlements are groups of humans engaged in socioeconomic processes, our means of collecting information about spatio-temporal distributions of population and socioeconomic variables often lack the spatial and temporal resolution to represent the processes at scales which they are known to occur. Furthermore, metrics and definitions often vary with country and through time. However, remote sensing provides globally consistent, synoptic observations of several proxies for human settlement at spatial and temporal resolutions sufficient to represent the evolution of settlements over the past 40 years. We use several independent but complementary proxies for anthropogenic land cover to quantify spatio-temporal (ST) evolution and scaling properties of human settlements globally. In this study we begin by comparing land cover and night lights in 8 diverse settings - each spanning gradients of population density and degree of land surface modification. Stable anthropogenic night light is derived from multi-temporal composites of emitted luminance measured by the VIIRS and DMSP-OLS sensors. Land cover is represented as mixtures of sub-pixel fractions of rock, soil and impervious Substrates, Vegetation and Dark surfaces (shadow, water and absorptive materials) estimated from Landsat imagery with > 94% accuracy. Multi-season stability and variability of land cover fractions effectively distinguishes between spectrally similar land covers that corrupt thematic classifications based on single images. We find that temporal stability of impervious substrates combined with persistent shadow cast between buildings results in temporally stable aggregate reflectance across seasons at the 30 m scale of a Landsat pixel. Comparison of night light brightness with land cover composition, stability and variability

Turbulence and pollutant transport in urban street canyons under stable stratification: a large-eddy simulation

NASA Astrophysics Data System (ADS)

Li, X.

2014-12-01

Thermal stratification of the atmospheric surface layer has strong impact on the land-atmosphere exchange of turbulent, heat, and pollutant fluxes. Few studies have been carried out for the interaction of the weakly to moderately stable stratified atmosphere and the urban canopy. This study performs a large-eddy simulation of a modeled street canyon within a weakly to moderately stable atmosphere boundary layer. To better resolve the smaller eddy size resulted from the stable stratification, a higher spatial and temporal resolution is used. The detailed flow structure and turbulence inside the street canyon are analyzed. The relationship of pollutant dispersion and Richardson number of the atmosphere is investigated. Differences between these characteristics and those under neutral and unstable atmosphere boundary layer are emphasized.

[Trapped temporal horn, an unusual form of obstructive hydrocephalus: 5 case-reports].

PubMed

Abderrahmen, K; Gdoura, Y; Kallel, J; Jemel, H

2016-04-01

"Entrapped temporal horn" is an unusual form of obstructive hydrocephalus which is due to an obstacle at the trigone of the lateral ventricle that seals off the temporal horn that may act as a space occupying process. In this study, our aim was to assess the clinical presentation, imaging, pathophysiology and the management of this entity. The medical records of patients with entrapped temporal horn diagnosed between January 2003 and December 2012 were reviewed retrospectively. Five patients were identified. In four cases, the condition developed after cranial surgery; an infant having two revisions of a ventriculoperitoneal shunt; an adult operated for a glioblastoma, an infant operated on for cerebral hydatidosis and an infant operated for an occipital encephalocele. In the last patient, the entrapped temporal horn revealed sarcoidosis. Trapped temporal horn syndrome can act as a space occupying process and requires surgical management. Internal shunting provides good results. However, the long term outcome depends on the etiology. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Functionally Stable and Phylogenetically Diverse Microbial Enrichments from Microbial Fuel Cells during Wastewater Treatment

PubMed Central

Ishii, Shun'ichi; Suzuki, Shino; Norden-Krichmar, Trina M.; Nealson, Kenneth H.; Sekiguchi, Yuji; Gorby, Yuri A.; Bretschger, Orianna

2012-01-01

Microbial fuel cells (MFCs) are devices that exploit microorganisms as biocatalysts to recover energy from organic matter in the form of electricity. One of the goals of MFC research is to develop the technology for cost-effective wastewater treatment. However, before practical MFC applications are implemented it is important to gain fundamental knowledge about long-term system performance, reproducibility, and the formation and maintenance of functionally-stable microbial communities. Here we report findings from a MFC operated for over 300 days using only primary clarifier effluent collected from a municipal wastewater treatment plant as the microbial resource and substrate. The system was operated in a repeat-batch mode, where the reactor solution was replaced once every two weeks with new primary effluent that consisted of different microbial and chemical compositions with every batch exchange. The turbidity of the primary clarifier effluent solution notably decreased, and 97% of biological oxygen demand (BOD) was removed after an 8–13 day residence time for each batch cycle. On average, the limiting current density was 1000 mA/m2, the maximum power density was 13 mW/m2, and coulombic efficiency was 25%. Interestingly, the electrochemical performance and BOD removal rates were very reproducible throughout MFC operation regardless of the sample variability associated with each wastewater exchange. While MFC performance was very reproducible, the phylogenetic analyses of anode-associated electricity-generating biofilms showed that the microbial populations temporally fluctuated and maintained a high biodiversity throughout the year-long experiment. These results suggest that MFC communities are both self-selecting and self-optimizing, thereby able to develop and maintain functional stability regardless of fluctuations in carbon source(s) and regular introduction of microbial competitors. These results contribute significantly toward the practical application of

Geographic, temporal, and age-specific variation in diets of Glaucous Gulls in western Alaska

USGS Publications Warehouse

Schmutz, J.A.; Hobson, K.A.

1998-01-01

We collected boluses and food remains of adult Glaucous Gulls (Larus hyperboreus) at or near nests and chicks, and digestive tracts from adults at three sites on the Yukon-Kuskokwim Delta, Alaska that differed in proximity to marine and terrestrial foods. We observed both geographic and temporal variation in diet; gulls consumed proportionately more terrestrial prey after peak hatch in late June, and gulls near the coast consumed proportionately more marine prey than gulls at two inland areas. Goslings occurred in > 60% of all samples from these inland areas. We compared these data to those from a previous study in western Alaska and found no marked differences. Evidence for similar patterns of geographic and temporal variation in diet was found using measurements of stable-carbon and nitrogen isotopes in gull and prey tissues. Stable isotope analysis further revealed that adult gulls consumed proportionately more marine prey (saffron cod, Eleginus gracilis) than they fed to their young. Using isotopic models, we estimated that 7-22% and 10-23% of the diet of adult and juvenile Glaucous Gulls, respectively, was comprised of terrestrial species. In addition to significant age-related variation, dietary estimates varied among geographic areas and between pre- and post-hatch periods. Overall, our isotopic estimates of the contribution of terrestrial prey to the diet of Glaucous Gulls was less than what may be inferred from conventional methods of diet analysis. Our study emphasizes the benefit of combining stable-isotope and conventional analyses to infer temporal and geographic changes in diet of wild birds and other organisms.

Phenology of stable fly (Diptera: Muscidae) larvae in round bale hay feeding sites in Eastern Nebraska

USDA-ARS?s Scientific Manuscript database

The temporal and spatial patterns of adult stable fly, Stomoxys calcitrans (L.), emergence from six sites where large round baled hay had been provided to pastured cattle as winter feed were studied using emergence traps. The substrate at these sites, consisting of waste hay mixed with bovine manure...

Temporal variability of bacterial communities in cryoconite on an alpine glacier.

PubMed

Franzetti, Andrea; Navarra, Federico; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Minora, Umberto; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Smiraglia, Claudio; Ambrosini, Roberto

2017-04-01

Cryoconite holes, that is, small ponds that form on glacier surface, are considered the most biologically active environments on glaciers. Bacterial communities in these environments have been extensively studied, but often through snapshot studies based on the assumption of a general stability of community structure. In this study, the temporal variation of bacterial communities in cryoconite holes on the Forni Glacier (Italian Alps) was investigated by high throughput DNA sequencing. A temporal change of bacterial communities was observed with autotrophic Cyanobacteria populations dominating communities after snowmelt, and heterotrophic Sphingobacteriales populations increasing in abundance later in the season. Bacterial communities also varied according to hole depth and area, amount of organic matter in the cryoconite and oxygen concentration. However, variation in environmental features explained a lower fraction of the variation in bacterial communities than temporal variation. Temporal change along ablation season seems therefore more important than local environmental conditions in shaping bacterial communities of cryoconite of the Forni Glacier. These findings challenge the assumption that bacterial communities of cryoconite holes are stable. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Economic agglomerations and spatio-temporal cycles in a spatial growth model with capital transport cost

NASA Astrophysics Data System (ADS)

Juchem Neto, J. P.; Claeyssen, J. C. R.; Pôrto Júnior, S. S.

2018-03-01

In this paper we introduce capital transport cost in a unidimensional spatial Solow-Swan model of economic growth with capital-induced labor migration, considered in an unbounded domain. Proceeding with a stability analysis, we show that there is a critical value for the capital transport cost where the dynamic behavior of the economy changes, provided that the intensity of capital-induced labor migration is strong enough. On the one hand, if the capital transport cost is higher than this critical value, the spatially homogeneous equilibrium of coexistence of the model is stable, and the economy converges to this spatially homogeneous state in the long run; on the other hand, if transport cost is lower than this critical value, the equilibrium is unstable, and the economy may develop different spatio-temporal dynamics, including the formation of stable economic agglomerations and spatio-temporal economic cycles, depending on the other parameters in the model. Finally, numerical simulations support the results of the stability analysis, and illustrate the spatio-temporal dynamics generated by the model, suggesting that the economy as a whole benefits from the formation of economic agglomerations and cycles, with a higher capital transport cost reducing this gain.

Stability of Synchronization Clusters and Seizurability in Temporal Lobe Epilepsy

PubMed Central

Palmigiano, Agostina; Pastor, Jesús; García de Sola, Rafael; Ortega, Guillermo J.

2012-01-01

Purpose Identification of critical areas in presurgical evaluations of patients with temporal lobe epilepsy is the most important step prior to resection. According to the “epileptic focus model”, localization of seizure onset zones is the main task to be accomplished. Nevertheless, a significant minority of epileptic patients continue to experience seizures after surgery (even when the focus is correctly located), an observation that is difficult to explain under this approach. However, if attention is shifted from a specific cortical location toward the network properties themselves, then the epileptic network model does allow us to explain unsuccessful surgical outcomes. Methods The intraoperative electrocorticography records of 20 patients with temporal lobe epilepsy were analyzed in search of interictal synchronization clusters. Synchronization was analyzed, and the stability of highly synchronized areas was quantified. Surrogate data were constructed and used to statistically validate the results. Our results show the existence of highly localized and stable synchronization areas in both the lateral and the mesial areas of the temporal lobe ipsilateral to the clinical seizures. Synchronization areas seem to play a central role in the capacity of the epileptic network to generate clinical seizures. Resection of stable synchronization areas is associated with elimination of seizures; nonresection of synchronization clusters is associated with the persistence of seizures after surgery. Discussion We suggest that synchronization clusters and their stability play a central role in the epileptic network, favoring seizure onset and propagation. We further speculate that the stability distribution of these synchronization areas would differentiate normal from pathologic cases. PMID:22844524

Selective amygdalohippocampectomy versus standard temporal lobectomy in patients with mesiotemporal lobe epilepsy and unilateral hippocampal sclerosis: post-operative facial emotion recognition abilities.

PubMed

Wendling, Anne-Sophie; Steinhoff, Bernhard J; Bodin, Frédéric; Staack, Anke M; Zentner, Josef; Scholly, Julia; Valenti, Maria-Paula; Schulze-Bonhage, Andreas; Hirsch, Edouard

2015-03-01

Surgical treatment of mesial temporal lobe epilepsy (mTLE) patients involves the removal either of the left or the right hippocampus. Since the mesial temporal lobe is responsible for emotion recognition abilities, we aimed to assess facial emotion recognition (FER) in two homogeneous patient cohorts that differed only in the administered surgery design since anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SAH) were performed independently of the underlying electroclinical conditions. The patient selection for the two respective surgical procedures was carried out retrospectively between 2000 and 2009 by two independent epilepsy centres, the Kork Epilepsy Centre, Germany and the University Hospital of Strasbourg, France. All included patients had presented with unilateral hippocampus sclerosis (HS) without associated dysplasia or white matter blurring and had become seizure-free postoperatively. Psychometric evaluation was carried out with the Ekman 60 Faces Test and screened for depression and psychosomatic symptoms with the SCL-90 R and the BDI. Thirty healthy volunteers participated as control subjects. Sixty patients were included, 27 had undergone SAH and 33 ATL. Patients and controls obtained comparable scores in FER for surprise, happiness, anger and sadness. Concerning fear and disgust the patient group scored significantly worse. Left-sided operations led to the the most pronounced impairment. The ATL group scored significantly worse for recognition of fear compared with SAH patients. Inversely, after SAH scores for disgust were significantly lower than after ATL, independently of the side of resection. Unilateral temporal damage impairs FER. Different neurosurgical procedures may affect FER differently. Copyright © 2015 Elsevier B.V. All rights reserved.

Geospatial modeling of plant stable isotope ratios - the development of isoscapes

NASA Astrophysics Data System (ADS)

West, J. B.; Ehleringer, J. R.; Hurley, J. M.; Cerling, T. E.

2007-12-01

Large-scale spatial variation in stable isotope ratios can yield critical insights into the spatio-temporal dynamics of biogeochemical cycles, animal movements, and shifts in climate, as well as anthropogenic activities such as commerce, resource utilization, and forensic investigation. Interpreting these signals requires that we understand and model the variation. We report progress in our development of plant stable isotope ratio landscapes (isoscapes). Our approach utilizes a GIS, gridded datasets, a range of modeling approaches, and spatially distributed observations. We synthesize findings from four studies to illustrate the general utility of the approach, its ability to represent observed spatio-temporal variability in plant stable isotope ratios, and also outline some specific areas of uncertainty. We also address two basic, but critical questions central to our ability to model plant stable isotope ratios using this approach: 1. Do the continuous precipitation isotope ratio grids represent reasonable proxies for plant source water?, and 2. Do continuous climate grids (as is or modified) represent a reasonable proxy for the climate experienced by plants? Plant components modeled include leaf water, grape water (extracted from wine), bulk leaf material ( Cannabis sativa; marijuana), and seed oil ( Ricinus communis; castor bean). Our approaches to modeling the isotope ratios of these components varied from highly sophisticated process models to simple one-step fractionation models to regression approaches. The leaf water isosocapes were produced using steady-state models of enrichment and continuous grids of annual average precipitation isotope ratios and climate. These were compared to other modeling efforts, as well as a relatively sparse, but geographically distributed dataset from the literature. The latitudinal distributions and global averages compared favorably to other modeling efforts and the observational data compared well to model predictions

Correlations of External Landmarks With Internal Structures of the Temporal Bone.

PubMed

Piromchai, Patorn; Wijewickrema, Sudanthi; Smeds, Henrik; Kennedy, Gregor; O'Leary, Stephen

2015-09-01

The internal anatomy of a temporal bone could be inferred from external landmarks. Mastoid surgery is an important skill that ENT surgeons need to acquire. Surgeons commonly use CT scans as a guide to understanding anatomical variations before surgery. Conversely, in cases where CT scans are not available, or in the temporal bone laboratory where residents are usually not provided with CT scans, it would be beneficial if the internal anatomy of a temporal bone could be inferred from external landmarks. We explored correlations between internal anatomical variations and metrics established to quantify the position of external landmarks that are commonly exposed in the operating room, or the temporal bone laboratory, before commencement of drilling. Mathematical models were developed to predict internal anatomy based on external structures. From an operating room view, the distances between the following external landmarks were observed to have statistically significant correlations with the internal anatomy of a temporal bone: temporal line, external auditory canal, mastoid tip, occipitomastoid suture, and Henle's spine. These structures can be used to infer a low lying dura mater (p = 0.002), an anteriorly located sigmoid sinus (p = 0.006), and a more lateral course of the facial nerve (p < 0.001). In the temporal bone laboratory view, the mastoid tegmen and sigmoid sinus were also regarded as external landmarks. The distances between these two landmarks and the operating view external structures were able to further infer the laterality of the facial nerve (p < 0.001) and a sclerotic mastoid (p < 0.001). Two nonlinear models were developed that predicted the distances between the following internal structures with a high level of accuracy: the distance from the sigmoid sinus to the posterior external auditory canal (p < 0.001) and the diameter of the round window niche (p < 0.001). The prospect of encountering some of the more technically challenging anatomical

Stable Imaging for Astronomy (SIA)

NASA Astrophysics Data System (ADS)

Beaulieu, Mathilde; Ottogalli, Sebastien; Preis, Olivier; Bresson, Yves; Rivet, Jean-Pierre; Abe, Lyu; Vakili, Farrokh

2014-07-01

One of the most challenging fields of astronomical instrumentation is probably high-contrast imaging since it ultimately combines ultra-high sensitivity at low flux and the ability to cope with photon flux contrasts of several hundreds of millions or even more. These two aspects implicitly require that high-contrast instruments should be highly stable in the sense of the reproducibility of their measurements at different times, but also, continuously stable over time. In most high contrast instruments or experiments, their sensitivity is broken after at most tens of minutes of operation due to uncontrolled and unknown behaviour of the whole experiment regarding the environmental conditions. In this paper, we introduce a general approach of an exhaustive stability study for high-contrast imaging that has been initiated at Lagrange Laboratory, Observatoire de la Côte d'Azur (OCA). On a practical ground, one of the fundamental issues of this study is the metrology, which is the basis of all reproducible measurements. We describe a small experiment designed to understand the behaviour of one of our ultra-precise metrology tools (a commercial sub-nanometric 3-way interferometer) and derive the conditions under which its operation delivers reliable results. The approach will apply to the high-contrast imaging test-bench SPEED, under development at OCA.

Temporal stability of novelty exploration in mice exposed to different open field tests.

PubMed

Kalueff, Allan V; Keisala, Tiina; Minasyan, Anna; Kuuslahti, Marianne; Tuohimaa, Pentti

2006-03-01

We investigated behavioural activity and temporal distribution (patterning) of mouse exploration in different open field (OF) arenas. Mice of 129S1 (S1) strain were subjected in parallel to three different OF arenas (Experiment 1), two different OF arenas in two trials (Experiment 2) or two trials of the same OF test (Experiment 3). Overall, mice demonstrated a high degree of similarity in the temporal profile of novelty-induced horizontal and vertical exploration (regardless of the size, colour and shape of the OF), which remained stable in subsequent OF exposures. In Experiments 4 and 5, we tested F1 hybrid mice (BALB/c-S1; NMRI-S1), and Vitamin D receptor knockout mice (generated on S1 genetic background), again showing strikingly similar temporal patterns of their OF exploration, despite marked behavioural strain differences in anxiety and activity. These results suggest that mice are characterised by stability of temporal organization of their exploration in different OF novelty situations.

Spatial and temporal analysis of postural control in dyslexic children.

PubMed

Gouleme, Nathalie; Gerard, Christophe Loic; Bui-Quoc, Emmanuel; Bucci, Maria Pia

2015-07-01

The aim of this study is to examine postural control of dyslexic children using both spatial and temporal analysis. Thirty dyslexic (mean age 9.7±0.3years) and thirty non-dyslexic age-matched children participated in the study. Postural stability was evaluated using Multitest Equilibre from Framiral®. Posture was recorded in the following conditions: eyes open fixating a target (EO) and eyes closed (EC) on stable (-S-) and unstable (-U-) platforms. The findings of this study showed poor postural stability in dyslexic children with respect to the non-dyslexic children group, as demonstrated by both spatial and temporal analysis. In both groups of children postural control depends on the condition, and improves when the eyes are open on a stable platform. Dyslexic children have spectral power indices that are higher than in non-dyslexic children and they showed a shorter cancelling time. Poor postural control in dyslexic children could be due to a deficit in using sensory information most likely caused by impairment in cerebellar activity. The reliability of brain activation patterns, namely in using sensory input and cerebellar activity may explain the deficit in postural control in dyslexic children. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Temporal contingency.

PubMed

Gallistel, C R; Craig, Andrew R; Shahan, Timothy A

2014-01-01

Contingency, and more particularly temporal contingency, has often figured in thinking about the nature of learning. However, it has never been formally defined in such a way as to make it a measure that can be applied to most animal learning protocols. We use elementary information theory to define contingency in such a way as to make it a measurable property of almost any conditioning protocol. We discuss how making it a measurable construct enables the exploration of the role of different contingencies in the acquisition and performance of classically and operantly conditioned behavior. Copyright © 2013 Elsevier B.V. All rights reserved.

Temporal contingency

PubMed Central

Gallistel, C.R.; Craig, Andrew R.; Shahan, Timothy A.

2015-01-01

Contingency, and more particularly temporal contingency, has often figured in thinking about the nature of learning. However, it has never been formally defined in such a way as to make it a measure that can be applied to most animal learning protocols. We use elementary information theory to define contingency in such a way as to make it a measurable property of almost any conditioning protocol. We discuss how making it a measurable construct enables the exploration of the role of different contingencies in the acquisition and performance of classically and operantly conditioned behavior. PMID:23994260

Temporal dynamics of catchment transit times from stable isotope data

NASA Astrophysics Data System (ADS)

Klaus, Julian; Chun, Kwok P.; McGuire, Kevin J.; McDonnell, Jeffrey J.

2015-06-01

Time variant catchment transit time distributions are fundamental descriptors of catchment function but yet not fully understood, characterized, and modeled. Here we present a new approach for use with standard runoff and tracer data sets that is based on tracking of tracer and age information and time variant catchment mixing. Our new approach is able to deal with nonstationarity of flow paths and catchment mixing, and an irregular shape of the transit time distribution. The approach extracts information on catchment mixing from the stable isotope time series instead of prior assumptions of mixing or the shape of transit time distribution. We first demonstrate proof of concept of the approach with artificial data; the Nash-Sutcliffe efficiencies in tracer and instantaneous transit times were >0.9. The model provides very accurate estimates of time variant transit times when the boundary conditions and fluxes are fully known. We then tested the model with real rainfall-runoff flow and isotope tracer time series from the H.J. Andrews Watershed 10 (WS10) in Oregon. Model efficiencies were 0.37 for the 18O modeling for a 2 year time series; the efficiencies increased to 0.86 for the second year underlying the need of long time tracer time series with a long overlap of tracer input and output. The approach was able to determine time variant transit time of WS10 with field data and showed how it follows the storage dynamics and related changes in flow paths where wet periods with high flows resulted in clearly shorter transit times compared to dry low flow periods.

Neocortical temporal FDG-PET hypometabolism correlates with temporal lobe atrophy in hippocampal sclerosis associated with microscopic cortical dysplasia.

PubMed

Diehl, Beate; LaPresto, Eric; Najm, Imad; Raja, Shanker; Rona, Sabine; Babb, Thomas; Ying, Zhong; Bingaman, William; Lüders, Hans O; Ruggieri, Paul

2003-04-01

Medically intractable temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), with or without cortical dysplasia (CD), is associated with atrophy of the hippocampal formation and regional fluorodeoxyglucose positron-emission tomography (FDG-PET) hypometabolism. The relation between areas of functional and structural abnormalities is not well understood. We investigate the relation between FDG-PET metabolism and temporal lobe (TL) and hippocampal atrophy in patients with histologically proven isolated HS and HS associated with CD. Twenty-three patients underwent en bloc resection of the mesial and anterolateral neocortical structures. Ten patients were diagnosed with isolated HS; 13 patients had associated microscopic CD. Temporal lobe volumes (TLVs) and hippocampal volumes were measured. Magnetic resonance imaging (MRI) and PET were co-registered, and regions of interest (ROIs) determined as gray matter of the mesial, lateral, and anterior temporal lobe. All patients (HS with or without CD) had significant ipsilateral PET hypometabolism in all three regions studied (p < 0.0001). In patients with isolated HS, the most prominent hypometabolism was in the anterior and mesial temporal lobe, whereas in dual pathology, it was in the lateral temporal lobe. TLVs and hippocampal volumes were significantly smaller on the epileptogenic side (p < 0.05). The PET asymmetries ipsilateral/contralateral to the epileptogenic zone and TLV asymmetries correlated significantly for the anterior and lateral temporal lobes (p < 0.05) in the HS+CD group, but not in the isolated HS group. Mesial temporal hypometabolism was not significantly different between the two groups. Temporal neocortical microscopic CD with concurrent HS is associated with more prominent lateral temporal metabolic dysfunction compared with isolated HS in TL atrophy. Further studies are needed to confirm these findings and correlate the PET hypometabolic patterns with outcome data in patients operated on for

Learning complex temporal patterns with resource-dependent spike timing-dependent plasticity.

PubMed

Hunzinger, Jason F; Chan, Victor H; Froemke, Robert C

2012-07-01

Studies of spike timing-dependent plasticity (STDP) have revealed that long-term changes in the strength of a synapse may be modulated substantially by temporal relationships between multiple presynaptic and postsynaptic spikes. Whereas long-term potentiation (LTP) and long-term depression (LTD) of synaptic strength have been modeled as distinct or separate functional mechanisms, here, we propose a new shared resource model. A functional consequence of our model is fast, stable, and diverse unsupervised learning of temporal multispike patterns with a biologically consistent spiking neural network. Due to interdependencies between LTP and LTD, dendritic delays, and proactive homeostatic aspects of the model, neurons are equipped to learn to decode temporally coded information within spike bursts. Moreover, neurons learn spike timing with few exposures in substantial noise and jitter. Surprisingly, despite having only one parameter, the model also accurately predicts in vitro observations of STDP in more complex multispike trains, as well as rate-dependent effects. We discuss candidate commonalities in natural long-term plasticity mechanisms.

Time reversal of arbitrary photonic temporal modes via nonlinear optical frequency conversion

NASA Astrophysics Data System (ADS)

Raymer, Michael G.; Reddy, Dileep V.; van Enk, Steven J.; McKinstrie, Colin J.

2018-05-01

Single-photon wave packets can carry quantum information between nodes of a quantum network. An important general operation in photon-based quantum information systems is ‘blind’ reversal of a photon’s temporal wave packet envelope, that is, the ability to reverse an envelope without knowing the temporal state of the photon. We present an all-optical means for doing so, using nonlinear-optical frequency conversion driven by a short pump pulse. The process used may be sum-frequency generation or four-wave Bragg scattering. This scheme allows for quantum operations such as a temporal-mode parity sorter. We also verify that the scheme works for arbitrary states (not only single-photon ones) of an unknown wave packet.

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.

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

Plant-pollinator interactions in a biodiverse meadow are rather stable and tight for 3 consecutive years.

PubMed

Fang, Qiang; Huang, Shuangquan

2016-05-01

Plant-pollinator interactions can be highly variable across years in natural communities. Although variation in the species composition and its basic structure has been investigated to understand the dynamic nature of pollination networks, little is known about the temporal dynamic of interaction strength between the same plant and pollinator species in any natural community. Pollinator-mediated selection on the evolution of floral traits could be diminished if plant-pollinator interactions vary temporally. To quantify the temporal variation in plant-pollinator interactions and the interaction strength (observed visits), we compared weighted networks between plants and pollinators in a biodiverse alpine meadow in Shangri-La, southwest China for 3 consecutive years. Although plant-pollinator interactions were highly dynamic such that identical interactions only accounted for 10.7% of the total between pair years, the diversity of interactions was stable. These identical interactions contributed 41.2% of total visits and were similar in strength and weighted nestedness. For plant species, 72.6% of species were visited by identical pollinator species between pair years, accounting for over half of the total visits and three-quarters at the functional group level. More generalized pollinators contributed more connectiveness and were more central in networks across years. However, there was no similar or even opposite trend for plant species, which suggested that specialized plant species may also be central in pollinator networks. The variation in pollinator composition decreased as pollinator species numbers increased, suggesting that generalized plants experienced stable pollinator partition. The stable, tight interactions between generalized pollinators and specialized plants represent cornerstones of the studied community. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Linearly first- and second-order, unconditionally energy stable schemes for the phase field crystal model

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

Yang, Xiaofeng, E-mail: xfyang@math.sc.edu; Han, Daozhi, E-mail: djhan@iu.edu

2017-02-01

In this paper, we develop a series of linear, unconditionally energy stable numerical schemes for solving the classical phase field crystal model. The temporal discretizations are based on the first order Euler method, the second order backward differentiation formulas (BDF2) and the second order Crank–Nicolson method, respectively. The schemes lead to linear elliptic equations to be solved at each time step, and the induced linear systems are symmetric positive definite. We prove that all three schemes are unconditionally energy stable rigorously. Various classical numerical experiments in 2D and 3D are performed to validate the accuracy and efficiency of the proposedmore » schemes.« less

Temporal Specificity in Pavlovian-Toinstrumental Transfer

ERIC Educational Resources Information Center

Matell, Matthew S.; Della Valle, Rebecca B.

2018-01-01

Presentation of a previously trained Pavlovian conditioned stimulus while an organism is engaged in operant responding can moderate the rate of responding, a phenomenon known as Pavlovian-to-instrumental transfer. Although it is well known that Pavlovian contingencies will generate conditioned behavior that is temporally organized with respect to…

Generation of stable subfemtosecond hard x-ray pulses with optimized nonlinear bunch compression

DOE PAGES

Huang, Senlin; Ding, Yuantao; Huang, Zhirong; ...

2014-12-15

In this paper, we propose a simple scheme that leverages existing x-ray free-electron laser hardware to produce stable single-spike, subfemtosecond x-ray pulses. By optimizing a high-harmonic radio-frequency linearizer to achieve nonlinear compression of a low-charge (20 pC) electron beam, we obtain a sharp current profile possessing a few-femtosecond full width at half maximum temporal duration. A reverse undulator taper is applied to enable lasing only within the current spike, where longitudinal space charge forces induce an electron beam time-energy chirp. Simulations based on the Linac Coherent Light Source parameters show that stable single-spike x-ray pulses with a duration less thanmore » 200 attoseconds can be obtained.« less

An Expanded Model of the Temporal Stability of Condom Use Intentions: Gender-Specific Predictors among High-Risk Adolescents

PubMed Central

Schmiege, Sarah J.; Bryan, Angela D.

2011-01-01

Background Adolescents involved with the criminal justice system are at particularly high-risk for the Human Immunodeficiency Virus and sexually transmitted infections. Purpose The purpose of this study was to longitudinally examine gender-specific models of condom use, incorporating temporal stability of intentions. Methods Adolescents on probation (N=728) were recruited to complete longitudinal surveys including measures of Theory of Planned Behavior and gender-specific constructs, relationship length, and condom use. Results Gender-specific models of condom use behavior suggested by previous research were mostly replicated. For young women, the effect of baseline intentions on subsequent condom use behavior was stronger when intentions were either stable or increasing. For young men, more stable, increasing intentions were directly associated with more condom use. There was preliminary evidence to suggest an association between temporal stability of intentions and decreasing condom use in stable relationships. Conclusions Intervention efforts should be tailored by gender and aim to forestall decreasing intentions and condom use over time by addressing difficulties in maintaining condom use. PMID:21347619

Stable isotope time series and dentin increments elucidate Pleistocene proboscidean paleobiology

NASA Astrophysics Data System (ADS)

Fisher, Daniel; Rountrey, Adam; Smith, Kathlyn; Fox, David

2010-05-01

Investigations of stable isotope composition of mineralized tissues have added greatly to our knowledge of past climates and dietary behaviors of organisms, even when they are implemented through 'bulk sampling', in which a single assay yields a single, time-averaged value. Likewise, the practice of 'sclerochronology', which documents periodic structural increments comprising a growth record for accretionary tissues, offers insights into rates of growth and age data at a scale of temporal resolution permitted by the nature of structural increments. We combine both of these approaches to analyze dental tissues of late Pleistocene proboscideans. Tusk dentin typically preserves a record of accretionary growth consisting of histologically distinct increments on daily, approximately weekly, and yearly time scales. Working on polished transverse or longitudinal sections, we mill out a succession of temporally controlled dentin samples bounded by clear structural increments with a known position in the sequence of tusk growth. We further subject each sample (or an aliquot thereof) to multiple compositional analyses - most frequently to assess δ18O and δ13C of hydroxyapatite carbonate, and δ13C and δ15N of collagen. This yields, for each animal and each series of years investigated, a set of parallel compositional time series with a temporal resolution of 1-2 months (or finer if we need additional precision). Patterns in variation of thickness of periodic sub-annual increments yield insight into intra-annual and inter-annual variation of tusk growth rate. This is informative even by itself, but it is still more valuable when coupled with compositional time series. Further, the controls on different stable isotope systems are sufficiently different that the data ensemble yields 'much more than the sum of its parts.' By assessing how compositions and growth rates covary, we monitor with greater confidence changes in local climate, diet, behavior, and health status. We

Phylogenetic community structure: temporal variation in fish assemblage

PubMed Central

Santorelli, Sergio; Magnusson, William; Ferreira, Efrem; Caramaschi, Erica; Zuanon, Jansen; Amadio, Sidnéia

2014-01-01

Hypotheses about phylogenetic relationships among species allow inferences about the mechanisms that affect species coexistence. Nevertheless, most studies assume that phylogenetic patterns identified are stable over time. We used data on monthly samples of fish from a single lake over 10 years to show that the structure in phylogenetic assemblages varies over time and conclusions depend heavily on the time scale investigated. The data set was organized in guild structures and temporal scales (grouped at three temporal scales). Phylogenetic distance was measured as the mean pairwise distances (MPD) and as mean nearest-neighbor distance (MNTD). Both distances were based on counts of nodes. We compared the observed values of MPD and MNTD with values that were generated randomly using null model independent swap. A serial runs test was used to assess the temporal independence of indices over time. The phylogenetic pattern in the whole assemblage and the functional groups varied widely over time. Conclusions about phylogenetic clustering or dispersion depended on the temporal scales. Conclusions about the frequency with which biotic processes and environmental filters affect the local assembly do not depend only on taxonomic grouping and spatial scales. While these analyzes allow the assertion that all proposed patterns apply to the fish assemblages in the floodplain, the assessment of the relative importance of these processes, and how they vary depending on the temporal scale and functional group studied, cannot be determined with the effort commonly used. It appears that, at least in the system that we studied, the assemblages are forming and breaking continuously, resulting in various phylogeny-related structures that makes summarizing difficult. PMID:25360256

Restoring Natural Streamflow Variability by Modifying Multi-purpose Reservoir Operation

NASA Astrophysics Data System (ADS)

Shiau, J.

2010-12-01

Multi-purpose reservoirs typically provide benefits of water supply, hydroelectric power, and flood mitigation. Hydroelectric power generations generally do not consume water. However, temporal distribution of downstream flows is highly changed due to hydro-peaking effects. Associated with offstream diversion of water supplies for municipal, industrial, and agricultural requirements, natural streamflow characteristics of magnitude, duration, frequency, timing, and rate of change is significantly altered by multi-purpose reservoir operation. Natural flow regime has long been recognized a master factor for ecosystem health and biodiversity. Restoration of altered flow regime caused by multi-purpose reservoir operation is the main objective of this study. This study presents an optimization framework that modifying reservoir operation to seeking balance between human and environmental needs. The methodology presented in this study is applied to the Feitsui Reservoir, located in northern Taiwan, with main purpose of providing stable water-supply and auxiliary purpose of electricity generation and flood-peak attenuation. Reservoir releases are dominated by two decision variables, i.e., duration of water releases for each day and percentage of daily required releases within the duration. The current releasing policy of the Feitsui Reservoir releases water for water-supply and hydropower purposes during 8:00 am to 16:00 pm each day and no environmental flows releases. Although greater power generation is obtained by 100% releases distributed within 8-hour period, severe temporal alteration of streamflow is observed downstream of the reservoir. Modifying reservoir operation by relaxing these two variables and reserve certain ratio of streamflow as environmental flow to maintain downstream natural variability. The optimal reservoir releasing policy is searched by the multi-criterion decision making technique for considering reservoir performance in terms of shortage ratio

Detailed temporal structure of communication networks in groups of songbirds.

PubMed

Stowell, Dan; Gill, Lisa; Clayton, David

2016-06-01

Animals in groups often exchange calls, in patterns whose temporal structure may be influenced by contextual factors such as physical location and the social network structure of the group. We introduce a model-based analysis for temporal patterns of animal call timing, originally developed for networks of firing neurons. This has advantages over cross-correlation analysis in that it can correctly handle common-cause confounds and provides a generative model of call patterns with explicit parameters for the influences between individuals. It also has advantages over standard Markovian analysis in that it incorporates detailed temporal interactions which affect timing as well as sequencing of calls. Further, a fitted model can be used to generate novel synthetic call sequences. We apply the method to calls recorded from groups of domesticated zebra finch (Taeniopygia guttata) individuals. We find that the communication network in these groups has stable structure that persists from one day to the next, and that 'kernels' reflecting the temporal range of influence have a characteristic structure for a calling individual's effect on itself, its partner and on others in the group. We further find characteristic patterns of influences by call type as well as by individual. © 2016 The Authors.

Delayed Reinforcement of Operant Behavior

ERIC Educational Resources Information Center

Lattal, Kennon A.

2010-01-01

The experimental analysis of delay of reinforcement is considered from the perspective of three questions that seem basic not only to understanding delay of reinforcement but also, by implication, the contributions of temporal relations between events to operant behavior. The first question is whether effects of the temporal relation between…

Qualitative and temporal reasoning in engine behavior analysis

NASA Technical Reports Server (NTRS)

Dietz, W. E.; Stamps, M. E.; Ali, M.

1987-01-01

Numerical simulation models, engine experts, and experimental data are used to generate qualitative and temporal representations of abnormal engine behavior. Engine parameters monitored during operation are used to generate qualitative and temporal representations of actual engine behavior. Similarities between the representations of failure scenarios and the actual engine behavior are used to diagnose fault conditions which have already occurred, or are about to occur; to increase the surveillance by the monitoring system of relevant engine parameters; and to predict likely future engine behavior.

Multi-material 3D Models for Temporal Bone Surgical Simulation.

PubMed

Rose, Austin S; Kimbell, Julia S; Webster, Caroline E; Harrysson, Ola L A; Formeister, Eric J; Buchman, Craig A

2015-07-01

A simulated, multicolor, multi-material temporal bone model can be created using 3-dimensional (3D) printing that will prove both safe and beneficial in training for actual temporal bone surgical cases. As the process of additive manufacturing, or 3D printing, has become more practical and affordable, a number of applications for the technology in the field of Otolaryngology-Head and Neck Surgery have been considered. One area of promise is temporal bone surgical simulation. Three-dimensional representations of human temporal bones were created from temporal bone computed tomography (CT) scans using biomedical image processing software. Multi-material models were then printed and dissected in a temporal bone laboratory by attending and resident otolaryngologists. A 5-point Likert scale was used to grade the models for their anatomical accuracy and suitability as a simulation of cadaveric and operative temporal bone drilling. The models produced for this study demonstrate significant anatomic detail and a likeness to human cadaver specimens for drilling and dissection. Simulated temporal bones created by this process have potential benefit in surgical training, preoperative simulation for challenging otologic cases, and the standardized testing of temporal bone surgical skills. © The Author(s) 2015.

Temporal and spatial variability in stable isotope compositions of a freshwater mussel: Implications for biomonitoring and ecological studies

USGS Publications Warehouse

Gustafson, L.; Showers, W.; Kwak, T.; Levine, J.; Stoskopf, M.

2007-01-01

Stable isotopes can be used to elucidate ecological relationships in community and trophic studies. Findings are calibrated against baselines, e.g. from a producer or primary consumer, assumed to act as a reference to the isotopic context created by spatio-temporal attributes such as geography, climate, nutrient, and energy sources. The ability of an organism to accurately represent a community base depends on how, and over what time-scale, it assimilates ambient materials. Freshwater mussels have served as references for trophic studies of freshwater communities and as indicators of change in nutrient pollution load or source. Their suitability as reference animals has not yet been fully explored, however. We conducted a series of studies examining the suitability of freshwater mussels as isotopic baselines, using their ability to reflect variation in ambient nutrient loads as a case scenario. (1) We analyzed bivalve foot tissue ??15N and ??13C from 22 stream reaches in the Piedmont region of North Carolina, USA to show that compositions varied substantially among locations. Site mean bivalve ??13C values correlated with site ambient particulate organic matter (POM) ??13C values, and site mean bivalve ??15N values correlated with site ambient water dissolved ??15N-NO3 values. (2) Similarity of results among sample types demonstrated that the minimally invasive hemolymph sample is a suitable substitute for foot tissue in ??15N analyses, and that small sample sizes generate means representative of a larger population. Both findings can help minimize the impact of sampling on imperiled freshwater mussel populations. (3) In a bivalve transplantation study we showed that hemolymph ??15N compositions responded to a shift in ambient dissolved ??15N-NO3, although slowly. The tissue turnover time for bivalve hemolymph was 113 days. We conclude that bivalves serve best as biomonitors of chronic, rather than acute, fluctuations in stream nutrient loads, and provide initial

Temporal Order in Periodically Driven Spins in Star-Shaped Clusters

NASA Astrophysics Data System (ADS)

Pal, Soham; Nishad, Naveen; Mahesh, T. S.; Sreejith, G. J.

2018-05-01

We experimentally study the response of star-shaped clusters of initially unentangled N =4 , 10, and 37 nuclear spin-1 /2 moments to an inexact π -pulse sequence and show that an Ising coupling between the center and the satellite spins results in robust period-2 magnetization oscillations. The period is stable against bath effects, but the amplitude decays with a timescale that depends on the inexactness of the pulse. Simulations reveal a semiclassical picture in which the rigidity of the period is due to a randomizing effect of the Larmor precession under the magnetization of surrounding spins. The timescales with stable periodicity increase with net initial magnetization, even in the presence of perturbations, indicating a robust temporal ordered phase for large systems with finite magnetization per spin.

Supporting temporal queries on clinical relational databases: the S-WATCH-QL language.

PubMed Central

Combi, C.; Missora, L.; Pinciroli, F.

1996-01-01

Due to the ubiquitous and special nature of time, specially in clinical datábases there's the need of particular temporal data and operators. In this paper we describe S-WATCH-QL (Structured Watch Query Language), a temporal extension of SQL, the widespread query language based on the relational model. S-WATCH-QL extends the well-known SQL by the addition of: a) temporal data types that allow the storage of information with different levels of granularity; b) historical relations that can store together both instantaneous valid times and intervals; c) some temporal clauses, functions and predicates allowing to define complex temporal queries. PMID:8947722

Results of the Stable Microgravity Vibration Isolation Flight Experiment

NASA Technical Reports Server (NTRS)

Edberg, Donald; Boucher, Robert; Schenck, David; Nurre, Gerald; Whorton, Mark; Kim, Young; Alhorn, Dean

1996-01-01

This paper presents an overview of the STABLE microgravity isolation system developed and successfully flight tested in October 1995. A description of the hardware design and operational principles is given. A sample of the measured flight data is presented, including an evaluation of attenuation performance provided by the actively controlled electromagnetic isolation system. Preliminary analyses of flight data show that the acceleration environment aboard STABLE's isolated platform was attenuated by a factor of more than 25 between 0.1 and 100 Hz. STABLE was developed under a cooperative agreement between National Aeronautics and Space Administration, Marshall Space Flight Center, and McDonnell Douglas Aerospace. The flight hardware was designed, fabricated, integrated, tested, and delivered to the Cape during a five month period.

Utilizing AI in Temporal, Spatial, and Resource Scheduling

NASA Technical Reports Server (NTRS)

Stottler, Richard; Kalton, Annaka; Bell, Aaron

2006-01-01

Aurora is a software system enabling the rapid, easy solution of complex scheduling problems involving spatial and temporal constraints among operations and scarce resources (such as equipment, workspace, and human experts). Although developed for use in the International Space Station Processing Facility, Aurora is flexible enough that it can be easily customized for application to other scheduling domains and adapted as the requirements change or become more precisely known over time. Aurora s scheduling module utilizes artificial-intelligence (AI) techniques to make scheduling decisions on the basis of domain knowledge, including knowledge of constraints and their relative importance, interdependencies among operations, and possibly frequent changes in governing schedule requirements. Unlike many other scheduling software systems, Aurora focuses on resource requirements and temporal scheduling in combination. For example, Aurora can accommodate a domain requirement to schedule two subsequent operations to locations adjacent to a shared resource. The graphical interface allows the user to quickly visualize the schedule and perform changes reflecting additional knowledge or alterations in the situation. For example, the user might drag the activity corresponding to the start of operations to reflect a late delivery.

Temporally precise single-cell resolution optogenetics

PubMed Central

Shemesh, Or A.; Tanese, Dimitrii; Zampini, Valeria; Linghu, Changyang; Piatkevich, Kiryl; Ronzitti, Emiliano; Papagiakoumou, Eirini; Boyden, Edward S.; Emiliani, Valentina

2017-01-01

Optogenetic control of individual neurons with high temporal precision, within intact mammalian brain circuitry, would enable powerful explorations of how neural circuits operate. Two-photon computer generated holography enables precise sculpting of light, and could in principle enable simultaneous illumination of many neurons in a network, with the requisite temporal precision to simulate accurate neural codes. We designed a high efficacy soma-targeted opsin, finding that fusing the N-terminal 150 residues of kainate receptor subunit 2 (KA2) to the recently discovered high-photocurrent channelrhodopsin CoChR restricted expression of this opsin primarily to the cell body of mammalian cortical neurons. In combination with two-photon holographic stimulation, we found that this somatic CoChR (soCoChR) enabled photostimulation of individual cells in intact cortical circuits with single cell resolution and <1 millisecond temporal precision, and use soCoChR to perform connectivity mapping on intact cortical circuits. PMID:29184208

Unsupervised learning of temporal features for word categorization in a spiking neural network model of the auditory brain.

PubMed

Higgins, Irina; Stringer, Simon; Schnupp, Jan

2017-01-01

The nature of the code used in the auditory cortex to represent complex auditory stimuli, such as naturally spoken words, remains a matter of debate. Here we argue that such representations are encoded by stable spatio-temporal patterns of firing within cell assemblies known as polychronous groups, or PGs. We develop a physiologically grounded, unsupervised spiking neural network model of the auditory brain with local, biologically realistic, spike-time dependent plasticity (STDP) learning, and show that the plastic cortical layers of the network develop PGs which convey substantially more information about the speaker independent identity of two naturally spoken word stimuli than does rate encoding that ignores the precise spike timings. We furthermore demonstrate that such informative PGs can only develop if the input spatio-temporal spike patterns to the plastic cortical areas of the model are relatively stable.

Unsupervised learning of temporal features for word categorization in a spiking neural network model of the auditory brain

PubMed Central

Stringer, Simon

2017-01-01

The nature of the code used in the auditory cortex to represent complex auditory stimuli, such as naturally spoken words, remains a matter of debate. Here we argue that such representations are encoded by stable spatio-temporal patterns of firing within cell assemblies known as polychronous groups, or PGs. We develop a physiologically grounded, unsupervised spiking neural network model of the auditory brain with local, biologically realistic, spike-time dependent plasticity (STDP) learning, and show that the plastic cortical layers of the network develop PGs which convey substantially more information about the speaker independent identity of two naturally spoken word stimuli than does rate encoding that ignores the precise spike timings. We furthermore demonstrate that such informative PGs can only develop if the input spatio-temporal spike patterns to the plastic cortical areas of the model are relatively stable. PMID:28797034

Development of a subway operation incident delay model using accelerated failure time approaches.

PubMed

Weng, Jinxian; Zheng, Yang; Yan, Xuedong; Meng, Qiang

2014-12-01

This study aims to develop a subway operational incident delay model using the parametric accelerated time failure (AFT) approach. Six parametric AFT models including the log-logistic, lognormal and Weibull models, with fixed and random parameters are built based on the Hong Kong subway operation incident data from 2005 to 2012, respectively. In addition, the Weibull model with gamma heterogeneity is also considered to compare the model performance. The goodness-of-fit test results show that the log-logistic AFT model with random parameters is most suitable for estimating the subway incident delay. First, the results show that a longer subway operation incident delay is highly correlated with the following factors: power cable failure, signal cable failure, turnout communication disruption and crashes involving a casualty. Vehicle failure makes the least impact on the increment of subway operation incident delay. According to these results, several possible measures, such as the use of short-distance and wireless communication technology (e.g., Wifi and Zigbee) are suggested to shorten the delay caused by subway operation incidents. Finally, the temporal transferability test results show that the developed log-logistic AFT model with random parameters is stable over time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anterior Temporal Lobe Morphometry Predicts Categorization Ability.

PubMed

Garcin, Béatrice; Urbanski, Marika; Thiebaut de Schotten, Michel; Levy, Richard; Volle, Emmanuelle

2018-01-01

Categorization is the mental operation by which the brain classifies objects and events. It is classically assessed using semantic and non-semantic matching or sorting tasks. These tasks show a high variability in performance across healthy controls and the cerebral bases supporting this variability remain unknown. In this study we performed a voxel-based morphometry study to explore the relationships between semantic and shape categorization tasks and brain morphometric differences in 50 controls. We found significant correlation between categorization performance and the volume of the gray matter in the right anterior middle and inferior temporal gyri. Semantic categorization tasks were associated with more rostral temporal regions than shape categorization tasks. A significant relationship was also shown between white matter volume in the right temporal lobe and performance in the semantic tasks. Tractography revealed that this white matter region involved several projection and association fibers, including the arcuate fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and inferior longitudinal fasciculus. These results suggest that categorization abilities are supported by the anterior portion of the right temporal lobe and its interaction with other areas.

Face and content validation of a virtual reality temporal bone simulator.

PubMed

Arora, Asit; Khemani, Sam; Tolley, Neil; Singh, Arvind; Budge, James; Varela, David A Diaz Voss; Francis, Howard W; Darzi, Ara; Bhatti, Nasir I

2012-03-01

To validate the VOXEL-MAN TempoSurg simulator for temporal bone dissection. Prospective international study. Otolaryngology departments of 2 academic health care institutions in the United Kingdom and United States. Eighty-five subjects were recruited consisting of an experienced and referent group. Participants performed a standardized familiarization session and temporal bone dissection task. Realism, training effectiveness, and global impressions were evaluated across 21 domains using a 5-point Likert-type scale. A score of 4 was the minimum threshold for acceptability. The experienced group comprised 25 otolaryngology trainers who had performed 150 mastoid operations. The referent group comprised 60 trainees (mean otolaryngology experience of 2.9 years). Familiarization took longer in the experienced group (P = .01). User-friendliness was positively rated (mean score 4.1). Seventy percent of participants rated anatomical appearance as acceptable. Trainers rated drill ergonomics worse than did trainees (P = .01). Simulation temporal bone training scored highly (mean score 4.3). Surgical anatomy, drill navigation, and hand-eye coordination accounted for this. Trainees were more likely to recommend temporal bone simulation to a colleague than were trainers (P = .01). Transferability of skills to the operating room was undecided (mean score 3.5). Realism of the VOXEL-MAN virtual reality temporal bone simulator is suboptimal in its current version. Nonetheless, it represents a useful adjunct to existing training methods and is particularly beneficial for novice surgeons before performing cadaveric temporal bone dissection. Improvements in realism, specifically drill ergonomics and visual-spatial perception during deeper temporal bone dissection, are warranted.

No strategy is evolutionarily stable in the repeated prisoner's dilemma.

PubMed

Lorberbaum, J

1994-05-21

Following the influential work of Axelrod, the repeated Prisoner's Dilemma game has become the theoretical gold standard for understanding the evolution of co-operative behavior among unrelated individuals. Using the game, several authors have found that a reciprocal strategy known as Tit for Tat (TFT) has done quite well in a wide range of environments. TFT strategists start out co-operating and then do what the other player did on the previous move. Despite the success of TFT and similar strategies in experimental studies of the game, Boyd & Lorberbaum (1987, Nature, Lond. 327, 58) have shown that no pure strategy, including TFT, is evolutionarily stable in the sense that each can be invaded by the joint effect of two invading strategies when long-term interaction occurs in the repeated game and future moves are discounted. Farrell & Ware (1989, Theor. Popul. Biol. 36, 161) have since extended these results to include finite mixes of pure strategies as well. Here, it is proven that no strategy is evolutionarily stable when long-term relationships are maintained in the repeated Prisoner's Dilemma and future moves are discounted. Namely, it is shown each completely probabilistic strategy (i.e. one that both co-operates and defects with positive probability after every sequence of behavior) may be invaded by a single deviant strategy. This completes the proof started by Boyd and Lorberbaum and extended by Farrell and Ware. This paper goes on to prove that no reactive strategy with a memory restricted to the opponent's preceding move is evolutionarily stable when there is no discounting of future moves. This is true despite the success of a more forgiving variant of TFT called GTFT in a recent tournament among reactive strategies conducted by Nowak & Sigmund (1992, Nature 355, 250) where future moves were not discounted. GTFT, for example, may be invaded by a pair of reactive mutants. Since no strategy is evolutionarily stable when future moves are discounted in the

Temporal dynamics of figure-ground segregation in human vision.

PubMed

Neri, Peter; Levi, Dennis M

2007-01-01

The segregation of figure from ground is arguably one of the most fundamental operations in human vision. Neural signals reflecting this operation appear in cortex as early as 50 ms and as late as 300 ms after presentation of a visual stimulus, but it is not known when these signals are used by the brain to construct the percepts of figure and ground. We used psychophysical reverse correlation to identify the temporal window for figure-ground signals in human perception and found it to lie within the range of 100-160 ms. Figure enhancement within this narrow temporal window was transient rather than sustained as may be expected from measurements in single neurons. These psychophysical results prompt and guide further electrophysiological studies.

An inverter-based capacitive trans-impedance amplifier readout with offset cancellation and temporal noise reduction for IR focal plane array

NASA Astrophysics Data System (ADS)

Chen, Hsin-Han; Hsieh, Chih-Cheng

2013-09-01

This paper presents a readout integrated circuit (ROIC) with inverter-based capacitive trans-impedance amplifier (CTIA) and pseudo-multiple sampling technique for infrared focal plane array (IRFPA). The proposed inverter-based CTIA with a coupling capacitor [1], executing auto-zeroing technique to cancel out the varied offset voltage from process variation, is used to substitute differential amplifier in conventional CTIA. The tunable detector bias is applied from a global external bias before exposure. This scheme not only retains stable detector bias voltage and signal injection efficiency, but also reduces the pixel area as well. Pseudo-multiple sampling technique [2] is adopted to reduce the temporal noise of readout circuit. The noise reduction performance is comparable to the conventional multiple sampling operation without need of longer readout time proportional to the number of samples. A CMOS image sensor chip with 55×65 pixel array has been fabricated in 0.18um CMOS technology. It achieves a 12um×12um pixel size, a frame rate of 72 fps, a power-per-pixel of 0.66uW/pixel, and a readout temporal noise of 1.06mVrms (16 times of pseudo-multiple sampling), respectively.

Entropy Stable Wall Boundary Conditions for the Compressible Navier-Stokes Equations

NASA Technical Reports Server (NTRS)

Parsani, Matteo; Carpenter, Mark H.; Nielsen, Eric J.

2014-01-01

Non-linear entropy stability and a summation-by-parts framework are used to derive entropy stable wall boundary conditions for the compressible Navier-Stokes equations. A semi-discrete entropy estimate for the entire domain is achieved when the new boundary conditions are coupled with an entropy stable discrete interior operator. The data at the boundary are weakly imposed using a penalty flux approach and a simultaneous-approximation-term penalty technique. Although discontinuous spectral collocation operators are used herein for the purpose of demonstrating their robustness and efficacy, the new boundary conditions are compatible with any diagonal norm summation-by-parts spatial operator, including finite element, finite volume, finite difference, discontinuous Galerkin, and flux reconstruction schemes. The proposed boundary treatment is tested for three-dimensional subsonic and supersonic flows. The numerical computations corroborate the non-linear stability (entropy stability) and accuracy of the boundary conditions.

Temporal and geographic patterns in population trends of brown-headed cowbirds

USGS Publications Warehouse

Peterjohn, B.G.; Sauer, J.R.; Schwarz, S.

2000-01-01

The temporal and geographic patterns in the population trends of Brown-headed Cowbirds are summarized from the North American Breeding Bird Survey. During 1966-1992, the survey-wide population declined significantly, a result of declining populations in the Eastern BBS Region, southern Great Plains, and the Pacific coast states. Increasing populations were most evident in the northern Great Plains. Cowbird populations were generally stable or increasing during 1966-1976, but their trends became more negative after 1976. The trends in cowbird populations were generally directly correlated with the trends of both host and nonhost species, suggesting that large-scale factors such as changing weather patterns, land use practices, or habitat availability were responsible for the observed temporal and geographic patterns in the trends of cowbirds and their hosts.

Temporal efficiency evaluation and small-worldness characterization in temporal networks

PubMed Central

Dai, Zhongxiang; Chen, Yu; Li, Junhua; Fam, Johnson; Bezerianos, Anastasios; Sun, Yu

2016-01-01

Numerous real-world systems can be modeled as networks. To date, most network studies have been conducted assuming stationary network characteristics. Many systems, however, undergo topological changes over time. Temporal networks, which incorporate time into conventional network models, are therefore more accurate representations of such dynamic systems. Here, we introduce a novel generalized analytical framework for temporal networks, which enables 1) robust evaluation of the efficiency of temporal information exchange using two new network metrics and 2) quantitative inspection of the temporal small-worldness. Specifically, we define new robust temporal network efficiency measures by incorporating the time dependency of temporal distance. We propose a temporal regular network model, and based on this plus the redefined temporal efficiency metrics and widely used temporal random network models, we introduce a quantitative approach for identifying temporal small-world architectures (featuring high temporal network efficiency both globally and locally). In addition, within this framework, we can uncover network-specific dynamic structures. Applications to brain networks, international trade networks, and social networks reveal prominent temporal small-world properties with distinct dynamic network structures. We believe that the framework can provide further insight into dynamic changes in the network topology of various real-world systems and significantly promote research on temporal networks. PMID:27682314

Temporal efficiency evaluation and small-worldness characterization in temporal networks

NASA Astrophysics Data System (ADS)

Dai, Zhongxiang; Chen, Yu; Li, Junhua; Fam, Johnson; Bezerianos, Anastasios; Sun, Yu

2016-09-01

Numerous real-world systems can be modeled as networks. To date, most network studies have been conducted assuming stationary network characteristics. Many systems, however, undergo topological changes over time. Temporal networks, which incorporate time into conventional network models, are therefore more accurate representations of such dynamic systems. Here, we introduce a novel generalized analytical framework for temporal networks, which enables 1) robust evaluation of the efficiency of temporal information exchange using two new network metrics and 2) quantitative inspection of the temporal small-worldness. Specifically, we define new robust temporal network efficiency measures by incorporating the time dependency of temporal distance. We propose a temporal regular network model, and based on this plus the redefined temporal efficiency metrics and widely used temporal random network models, we introduce a quantitative approach for identifying temporal small-world architectures (featuring high temporal network efficiency both globally and locally). In addition, within this framework, we can uncover network-specific dynamic structures. Applications to brain networks, international trade networks, and social networks reveal prominent temporal small-world properties with distinct dynamic network structures. We believe that the framework can provide further insight into dynamic changes in the network topology of various real-world systems and significantly promote research on temporal networks.

Time-stable overset grid method for hyperbolic problems using summation-by-parts operators

NASA Astrophysics Data System (ADS)

Sharan, Nek; Pantano, Carlos; Bodony, Daniel J.

2018-05-01

A provably time-stable method for solving hyperbolic partial differential equations arising in fluid dynamics on overset grids is presented in this paper. The method uses interface treatments based on the simultaneous approximation term (SAT) penalty method and derivative approximations that satisfy the summation-by-parts (SBP) property. Time-stability is proven using energy arguments in a norm that naturally relaxes to the standard diagonal norm when the overlap reduces to a traditional multiblock arrangement. The proposed overset interface closures are time-stable for arbitrary overlap arrangements. The information between grids is transferred using Lagrangian interpolation applied to the incoming characteristics, although other interpolation schemes could also be used. The conservation properties of the method are analyzed. Several one-, two-, and three-dimensional, linear and non-linear numerical examples are presented to confirm the stability and accuracy of the method. A performance comparison between the proposed SAT-based interface treatment and the commonly-used approach of injecting the interpolated data onto each grid is performed to highlight the efficacy of the SAT method.

Elastomeric Microchip Electrospray Emitter for Stable Cone-Jet Mode Operation in the Nano-Flow Regime

PubMed Central

Kelly, Ryan T.; Tang, Keqi; Irimia, Daniel; Toner, Mehmet; Smith, Richard D.

2009-01-01

Despite widespread interest in combining lab-on-a-chip technologies with mass spectrometry (MS)-based analyses, the coupling of microfluidics to electrospray ionization (ESI)-MS remains challenging. We report a robust, integrated poly(dimethylsiloxane) microchip interface for ESI-MS using simple and widely accessible microfabrication procedures. The interface uses an auxiliary channel to provide electrical contact for the stable cone-jet electrospray without sample loss or dilution. The electric field at the channel terminus is enhanced by two vertical cuts that cause the interface to taper to a line rather than to a point, and the formation of a small Taylor cone at the channel exit ensures sub-nL post-column dead volumes. Cone-jet mode electrospray was demonstrated for up to 90% aqueous solutions and for extended durations. Comparable ESI-MS sensitivities were achieved using both microchip and conventional fused silica capillary emitters, but stable cone-jet mode electrosprays could be established over a far broader range of flow rates (from 50-1000 nL/min) and applied potentials using the microchip emitters. This attribute of the microchip emitter should simplify electrospray optimization and make the stable electrospray more resistant to external perturbations. PMID:18419138

Stable, semi-stable populations and growth potential.

PubMed

Bourgeois-Pichat, J

1971-07-01

Abstract Starting from the definition of a Malthusian population given by Alfred J. Lotka, the author recalls how the concept of stable population is introduced in demography, first as a particular case of stable populations, and secondly as a limit of a demographic evolutionary process in which female age-specific fertility rates and age-specific mortality rates remain constant. Then he defines a new concept: the semi-stable population which is a population with a constant age distribution. He shows that such a population coincides at any point of time with the stable population corresponding to the mortality and the fertility at this point of time. In the remaining part of the paper it is shown how the concept of a stable population can be used for defining a coefficient of inertia which measures the resistance of a population to modification of its course as a consequence of changing fertility and mortality. Some formulae are established to calculate this coefficient first for an arbitrary population, and secondly for a semistable population. In this second case the formula is particularly simple. It appears as a product of three terms: the expectation of life at birth in years, the crude birth rate, and a coefficient depending on the rate of growth and for which a numerical table is easy to establish.

Multi-temporal change image inference towards false alarms reduction for an operational photogrammetric rockfall detection system

NASA Astrophysics Data System (ADS)

Partsinevelos, Panagiotis; Kallimani, Christina; Tripolitsiotis, Achilleas

2015-06-01

Rockfall incidents affect civil security and hamper the sustainable growth of hard to access mountainous areas due to casualties, injuries and infrastructure loss. Rockfall occurrences cannot be easily prevented, whereas previous studies for rockfall multiple sensor early detection systems have focused on large scale incidents. However, even a single rock may cause the loss of a human life along transportation routes thus, it is highly important to establish methods for the early detection of small-scale rockfall incidents. Terrestrial photogrammetric techniques are prone to a series of errors leading to false alarm incidents, including vegetation, wind, and non relevant change in the scene under consideration. In this study, photogrammetric monitoring of rockfall prone slopes is established and the resulting multi-temporal change imagery is processed in order to minimize false alarm incidents. Integration of remote sensing imagery analysis techniques is hereby applied to enhance early detection of a rockfall. Experimental data demonstrated that an operational system able to identify a 10-cm rock movement within a 10% false alarm rate is technically feasible.

Spatio-Temporal Analysis of Surface Soil Moisture in Evaluating Ground Truth Monitoring Sites for Remotely Sensed Observations

USDA-ARS?s Scientific Manuscript database

Soil moisture is an intrinsic state variable that varies considerably in space and time. Although soil moisture is highly variable, repeated measurements of soil moisture at the field or small watershed scale can often reveal certain locations as being temporally stable and representative of the are...

A novel setup for femtosecond pump-repump-probe IR spectroscopy with few cycle CEP stable pulses.

PubMed

Bradler, Maximilian; Werhahn, Jasper C; Hutzler, Daniel; Fuhrmann, Simon; Heider, Rupert; Riedle, Eberhard; Iglev, Hristo; Kienberger, Reinhard

2013-08-26

We present a three-color mid-IR setup for vibrational pump-repump-probe experiments with a temporal resolution well below 100 fs and a freely selectable spectral resolution of 20 to 360 cm(-1) for the pump and repump. The usable probe range without optical realignment is 900 cm(-1). The experimental design employed is greatly simplified compared to the widely used setups, highly robust and includes a novel means for generation of tunable few-cycle pulses with stable carrier-envelope phase. A Ti:sapphire pump system operating with 1 kHz and a modest 150 fs pulse duration supplies the total pump energy of just 0.6 mJ. The good signal-to-noise ratio of the setup allows the determination of spectrally resolved transient probe changes smaller than 6·10(-5) OD at 130 time delays in just 45 minutes. The performance of the spectrometer is demonstrated with transient IR spectra and decay curves of HDO molecules in lithium nitrate trihydrate and ice and a first all MIR pump-repump-probe measurement.

Longitudinal progression of frontal and temporal lobe changes in schizophrenia

PubMed Central

Cobia, Derin J.; Smith, Matthew J.; Wang, Lei; Csernansky, John G.

2012-01-01

Cortical abnormalities are considered a neurobiological characteristic of schizophrenia. However, the pattern of such deficits as they progress over the illness remains poorly understood. The goal of this project was to assess the progression of cortical thinning in frontal and temporal cortical regions in schizophrenia, and determine whether relationships exist between them and neuropsychological and clinical symptom profiles. As part of a larger longitudinal 2-year follow-up study, schizophrenia (n=20) and healthy participants (n=20) group-matched for age, gender, and recent-alcohol use, were selected. Using MRI, estimates of gray matter thickness were derived from primary anatomical gyri of the frontal and temporal lobes using surface-based algorithms. These values were entered into repeated-measures analysis of variance models to determine group status and time effects. Change values in cortical regions were correlated with changes in neuropsychological functioning and clinical symptomatology. Results revealed exaggerated cortical thinning of the middle frontal, superior temporal, and middle temporal gyri in schizophrenia participants. These thickness changes strongly influenced volumetric reductions, but were not related to shrinking surface area. Neuropsychological and clinical symptom profiles were stable in the schizophrenia participants despite these neuroanatomic changes. Overall it appears ongoing abnormalities in the cerebral cortex continue after initial onset of schizophrenia, particularly the lateral aspects of frontal and temporal regions, and do not relate to neuropsychological or clinical measures over time. Maintenance of neuropsychological performance and clinical stability in the face of changing neuroanatomical structure suggests the involvement of alternative compensatory mechanisms. PMID:22647883

Longitudinal progression of frontal and temporal lobe changes in schizophrenia.

PubMed

Cobia, Derin J; Smith, Matthew J; Wang, Lei; Csernansky, John G

2012-08-01

Cortical abnormalities are considered a neurobiological characteristic of schizophrenia. However, the pattern of such deficits as they progress over the illness remains poorly understood. The goal of this project was to assess the progression of cortical thinning in frontal and temporal cortical regions in schizophrenia, and determine whether relationships exist between them and neuropsychological and clinical symptom profiles. As part of a larger longitudinal 2-year follow-up study, schizophrenia (n=20) and healthy participants (n=20) group-matched for age, gender, and recent-alcohol use, were selected. Using MRI, estimates of gray matter thickness were derived from primary anatomical gyri of the frontal and temporal lobes using surface-based algorithms. These values were entered into repeated-measures analysis of variance models to determine group status and time effects. Change values in cortical regions were correlated with changes in neuropsychological functioning and clinical symptomatology. Results revealed exaggerated cortical thinning of the middle frontal, superior temporal, and middle temporal gyri in schizophrenia participants. These thickness changes strongly influenced volumetric reductions, but were not related to shrinking surface area. Neuropsychological and clinical symptom profiles were stable in the schizophrenia participants despite these neuroanatomic changes. Overall it appears that ongoing abnormalities in the cerebral cortex continue after initial onset of schizophrenia, particularly the lateral aspects of frontal and temporal regions, and do not relate to neuropsychological or clinical measures over time. Maintenance of neuropsychological performance and clinical stability in the face of changing neuroanatomical structure suggests the involvement of alternative compensatory mechanisms. Copyright © 2012 Elsevier B.V. All rights reserved.

Spatio-temporal Hotelling observer for signal detection from image sequences

PubMed Central

Caucci, Luca; Barrett, Harrison H.; Rodríguez, Jeffrey J.

2010-01-01

Detection of signals in noisy images is necessary in many applications, including astronomy and medical imaging. The optimal linear observer for performing a detection task, called the Hotelling observer in the medical literature, can be regarded as a generalization of the familiar prewhitening matched filter. Performance on the detection task is limited by randomness in the image data, which stems from randomness in the object, randomness in the imaging system, and randomness in the detector outputs due to photon and readout noise, and the Hotelling observer accounts for all of these effects in an optimal way. If multiple temporal frames of images are acquired, the resulting data set is a spatio-temporal random process, and the Hotelling observer becomes a spatio-temporal linear operator. This paper discusses the theory of the spatio-temporal Hotelling observer and estimation of the required spatio-temporal covariance matrices. It also presents a parallel implementation of the observer on a cluster of Sony PLAYSTATION 3 gaming consoles. As an example, we consider the use of the spatio-temporal Hotelling observer for exoplanet detection. PMID:19550494

Spatio-temporal Hotelling observer for signal detection from image sequences.

PubMed

Caucci, Luca; Barrett, Harrison H; Rodriguez, Jeffrey J

2009-06-22

Detection of signals in noisy images is necessary in many applications, including astronomy and medical imaging. The optimal linear observer for performing a detection task, called the Hotelling observer in the medical literature, can be regarded as a generalization of the familiar prewhitening matched filter. Performance on the detection task is limited by randomness in the image data, which stems from randomness in the object, randomness in the imaging system, and randomness in the detector outputs due to photon and readout noise, and the Hotelling observer accounts for all of these effects in an optimal way. If multiple temporal frames of images are acquired, the resulting data set is a spatio-temporal random process, and the Hotelling observer becomes a spatio-temporal linear operator. This paper discusses the theory of the spatio-temporal Hotelling observer and estimation of the required spatio-temporal covariance matrices. It also presents a parallel implementation of the observer on a cluster of Sony PLAYSTATION 3 gaming consoles. As an example, we consider the use of the spatio-temporal Hotelling observer for exoplanet detection.

An implicit spatial and high-order temporal finite difference scheme for 2D acoustic modelling

NASA Astrophysics Data System (ADS)

Wang, Enjiang; Liu, Yang

2018-01-01

The finite difference (FD) method exhibits great superiority over other numerical methods due to its easy implementation and small computational requirement. We propose an effective FD method, characterised by implicit spatial and high-order temporal schemes, to reduce both the temporal and spatial dispersions simultaneously. For the temporal derivative, apart from the conventional second-order FD approximation, a special rhombus FD scheme is included to reach high-order accuracy in time. Compared with the Lax-Wendroff FD scheme, this scheme can achieve nearly the same temporal accuracy but requires less floating-point operation times and thus less computational cost when the same operator length is adopted. For the spatial derivatives, we adopt the implicit FD scheme to improve the spatial accuracy. Apart from the existing Taylor series expansion-based FD coefficients, we derive the least square optimisation based implicit spatial FD coefficients. Dispersion analysis and modelling examples demonstrate that, our proposed method can effectively decrease both the temporal and spatial dispersions, thus can provide more accurate wavefields.

Circular array of stable atmospheric pressure microplasmas

NASA Astrophysics Data System (ADS)

Wu, C.; Zhang, Z.-B.; Hoskinson, A.; Hopwood, J.

2010-12-01

A circular array composed of six quarter-wavelength microstripline resonators sustains a stable ring-shaped microplasma in atmospheric pressure argon. A single power source (1 GHz, <5 W) drives all six resonators. The operation of the array is modeled by coupled mode theory (CMT) and confirmed by electromagnetic simulations. Non-uniformities in the plasma ring are attributed to parasitic plasma sheath capacitance and confirmed by CMT.

Multi-dimensional stable fundamental solitons and excitations in PT-symmetric harmonic-Gaussian potentials with unbounded gain-and-loss distributions

NASA Astrophysics Data System (ADS)

Chen, Yong; Yan, Zhenya

2018-04-01

We demonstrate the parity-time- (PT-) symmetric harmonic-Gaussian potential with unbounded gain-and-loss distribution can support entirely-real linear spectra, stable spatial and spatio-temporal solitons in an inhomogeneous nonlinear medium (e.g., cubic nonlinear Schrödinger equation with the self-focusing and defocusing cases). Exact analytical solitons are derived in both one-dimensional (1D) and higher-dimensional (e.g., 2D, 3D) geometries such that they are verified to be stable in the given parameters regions. Particularly, several families of numerical fundamental solitons (especially the 1D double-peaked solitons, 2D vortex solitons, and 3D double bullets) can be found to be stable around the propagation parameters for exact solitons. Other significant properties of solitons are also explored including the interactions of solitons, stable soliton excitations, and transverse power flows. The results may excite the corresponding theoretical analysis and experiment designs.

Navigation-assisted trans-inferotemporal cortex selective amygdalohippocampectomy for mesial temporal lobe epilepsy; preserving the temporal stem.

PubMed

Kishima, Haruhiko; Kato, Amami; Oshino, Satoru; Tani, Naoki; Maruo, Tomoyuki; Khoo, Hui Ming; Yanagisawa, Takufumi; Edakawa, Kotaro; Kobayashi, Maki; Tanaka, Masataka; Hosomi, Koichi; Hirata, Masayuki; Yoshimine, Toshiki

2017-03-01

Selective amygdalohippocampectomy (SAH) can be used to obtain satisfactory seizure control in patients with mesial temporal lobe epilepsy (MTLE). Several SAH procedures have been reported to achieve satisfactory outcomes for seizure control, but none yield fully satisfactory outcomes for memory function. We hypothesized that preserving the temporal stem might play an important role. To preserve the temporal stem, we developed a minimally invasive surgical procedure, 'neuronavigation-assisted trans-inferotemporal cortex SAH' (TITC-SAH). TITC-SAH was performed in 23 patients with MTLE (MTLE on the language-non-dominant hemisphere, n = 11). The inferior horn of the lateral ventricle was approached via the inferior or middle temporal gyrus along the inferior temporal sulcus under neuronavigation guidance. The hippocampus was dissected in a subpial manner and resected en bloc together with the parahippocampal gyrus. Seizure control at one year and memory function at 6 months postoperatively were evaluated. One year after TITC-SAH, 20 of the 23 patients were seizure-free (ILAE class 1), 2 were class 2, and 1 was class 3. Verbal memory improved significantly in 13 patients with a diagnosis of hippocampal sclerosis, for whom WMS-R scores were available both pre- and post-operatively. Improvements were seen regardless of whether the SAH was on the language-dominant or non-dominant hemisphere. No major complication was observed. Navigation-assisted TITC-SAH performed for MTLE offers a simple, minimally invasive procedure that appears to yield excellent outcomes in terms of seizure control and preservation of memory function, because this procedure does not damage the temporal stem. TITC-SAH should be one of the feasible surgical procedures for MTLE. SAH: Amygdalohippocampectomy; MTLE: Mesial temporal lobe epilepsy (MTLE); TITC-SAH: Ttrans-inferotemporal cortex SAH; ILAE: International League Against Epilepsy (ILAE); MRI: Magnetic resonance imaging; EEG

Mining Recent Temporal Patterns for Event Detection in Multivariate Time Series Data

PubMed Central

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

2015-01-01

Improving the performance of classifiers using pattern mining techniques has been an active topic of data mining research. In this work we introduce the recent temporal pattern mining framework for finding predictive patterns for monitoring and event detection problems in complex multivariate time series data. This framework first converts time series into time-interval sequences of temporal abstractions. It then constructs more complex temporal patterns backwards in time using temporal operators. We apply our framework to health care data of 13,558 diabetic patients and show its benefits by efficiently finding useful patterns for detecting and diagnosing adverse medical conditions that are associated with diabetes. PMID:25937993

Spatio-temporal examination of precipitation isotopes from the North American monsoon in Arizona, New Mexico, and Utah from 2014 to 2017

NASA Astrophysics Data System (ADS)

Tulley-Cordova, C. L.; Bowen, G. J.

2017-12-01

A significant summertime feature of climate in the southwestern United States (US) is the North American monsoon (NAM), also known as the Mexican monsoon, Arizona monsoon, and the southwestern United States monsoon. NAM is a crucial contributor to total annual precipitation in the Four Corners region of the US. Modern investigation of NAM in this region using stable isotopes has been poorly studied. This study characterizes the spatio-temporal changes of NAM based on stable isotopic results from 40 sites, located within the boundaries of the Navajo Nation, in Arizona, New Mexico, and Utah from 2014 to 2017. Sample collections were collected monthly at each site from May to October. Examination of temporal trends of precipitation revealed strong monthly and interannual changes; spatial analysis showed weak large-scale relationships across the study area. Analysis of stable isotopes in precipitation, surface, ground, and spring waters can be used to interpret the isotopic differences in the modern hydro-climate of the Navajo Nation and Colorado Plateau to help predict future hydro-climate changes and its implications on future water resources.

The efficacy of a panel study for assessing the temporal stability of hunting participation and constraints

Treesearch

Ellen B. Drogin Rodgers; Brett A. Wright; Kenneth F. Backman

2003-01-01

The intent of this study of Virginia hunters/nonhunters was to test the efficacy of panel research for assessing the temporal stability of hunting participation and constraints. Findings suggest that participation/nonparticipation patterns were stable across time periods for the population, yet dynamic at the individual level. Although the structure of perceived...

Evaluating and implementing temporal, spatial, and spatio-temporal methods for outbreak detection in a local syndromic surveillance system.

PubMed

Mathes, Robert W; Lall, Ramona; Levin-Rector, Alison; Sell, Jessica; Paladini, Marc; Konty, Kevin J; Olson, Don; Weiss, Don

2017-01-01

The New York City Department of Health and Mental Hygiene has operated an emergency department syndromic surveillance system since 2001, using temporal and spatial scan statistics run on a daily basis for cluster detection. Since the system was originally implemented, a number of new methods have been proposed for use in cluster detection. We evaluated six temporal and four spatial/spatio-temporal detection methods using syndromic surveillance data spiked with simulated injections. The algorithms were compared on several metrics, including sensitivity, specificity, positive predictive value, coherence, and timeliness. We also evaluated each method's implementation, programming time, run time, and the ease of use. Among the temporal methods, at a set specificity of 95%, a Holt-Winters exponential smoother performed the best, detecting 19% of the simulated injects across all shapes and sizes, followed by an autoregressive moving average model (16%), a generalized linear model (15%), a modified version of the Early Aberration Reporting System's C2 algorithm (13%), a temporal scan statistic (11%), and a cumulative sum control chart (<2%). Of the spatial/spatio-temporal methods we tested, a spatial scan statistic detected 3% of all injects, a Bayes regression found 2%, and a generalized linear mixed model and a space-time permutation scan statistic detected none at a specificity of 95%. Positive predictive value was low (<7%) for all methods. Overall, the detection methods we tested did not perform well in identifying the temporal and spatial clusters of cases in the inject dataset. The spatial scan statistic, our current method for spatial cluster detection, performed slightly better than the other tested methods across different inject magnitudes and types. Furthermore, we found the scan statistics, as applied in the SaTScan software package, to be the easiest to program and implement for daily data analysis.

Evaluating and implementing temporal, spatial, and spatio-temporal methods for outbreak detection in a local syndromic surveillance system

PubMed Central

Lall, Ramona; Levin-Rector, Alison; Sell, Jessica; Paladini, Marc; Konty, Kevin J.; Olson, Don; Weiss, Don

2017-01-01

The New York City Department of Health and Mental Hygiene has operated an emergency department syndromic surveillance system since 2001, using temporal and spatial scan statistics run on a daily basis for cluster detection. Since the system was originally implemented, a number of new methods have been proposed for use in cluster detection. We evaluated six temporal and four spatial/spatio-temporal detection methods using syndromic surveillance data spiked with simulated injections. The algorithms were compared on several metrics, including sensitivity, specificity, positive predictive value, coherence, and timeliness. We also evaluated each method’s implementation, programming time, run time, and the ease of use. Among the temporal methods, at a set specificity of 95%, a Holt-Winters exponential smoother performed the best, detecting 19% of the simulated injects across all shapes and sizes, followed by an autoregressive moving average model (16%), a generalized linear model (15%), a modified version of the Early Aberration Reporting System’s C2 algorithm (13%), a temporal scan statistic (11%), and a cumulative sum control chart (<2%). Of the spatial/spatio-temporal methods we tested, a spatial scan statistic detected 3% of all injects, a Bayes regression found 2%, and a generalized linear mixed model and a space-time permutation scan statistic detected none at a specificity of 95%. Positive predictive value was low (<7%) for all methods. Overall, the detection methods we tested did not perform well in identifying the temporal and spatial clusters of cases in the inject dataset. The spatial scan statistic, our current method for spatial cluster detection, performed slightly better than the other tested methods across different inject magnitudes and types. Furthermore, we found the scan statistics, as applied in the SaTScan software package, to be the easiest to program and implement for daily data analysis. PMID:28886112

Monitoring Spatial Variability and Temporal Dynamics of Phragmites Using Unmanned Aerial Vehicles

PubMed Central

Tóth, Viktor R.

2018-01-01

Littoral zones of freshwater lakes are exposed to environmental impacts from both terrestrial and aquatic sides, while substantial anthropogenic pressure also affects the high spatial, and temporal variability of the ecotone. In this study, the possibility of monitoring seasonal and spatial changes in reed (Phragmites australis) stands using an unmanned aerial vehicle (UAV) based remote sensing technique was examined. Stands in eutrophic and mesotrophic parts of Lake Balaton including not deteriorating (stable) and deteriorating (die-back) patches, were tracked throughout the growing season using a UAV equipped with a Normalized Difference Vegetation Index (NDVI) camera. Photophysiological parameters of P. australis were also measured with amplitude modulated fluorescence. Parameters characterizing the dynamics of seasonal changes in NDVI data were used for phenological comparison of eutrophic and mesotrophic, stable and die-back, terrestrial and aquatic, mowed and not-mowed patches of reed. It was shown that stable Phragmites plants from the eutrophic part of the lake reached specific phenological stages up to 3.5 days earlier than plants from the mesotrophic part of the lake. The phenological changes correlated with trophic (total and nitrate-nitrite nitrogen) and physical (organic C and clay content) properties of the sediment, while only minor relationships with air and water temperature were found. Phenological differences between the stable and die-back stands were even more pronounced, with ~34% higher rates of NDVI increase in stable than die-back patches, while the period of NDVI increase was 16 days longer. Aquatic and terrestrial parts of reed stands showed no phenological differences, although intermediate areas (shallow water parts of stands) were found to be less vigorous. Winter mowing of dried Phragmites sped up sprouting and growth of reed in the spring. This study showed that remote sensing-derived photophysiological and phenological variability

Clinical correlation of biopsy results in patients with temporal arteritis.

PubMed

Yuksel, Volkan; Guclu, Orkut; Tastekin, Ebru; Halici, Umit; Huseyin, Serhat; Inal, Volkan; Canbaz, Suat

2017-11-01

Temporal arteritis is systemic vasculitis of medium and large sized vessels. The lowest incidence rates were reported in Turkey, Japan and Israel. We aimed to investigate the results of patients with biopsy-proven temporal arteritis and those classified according to the American College of Rheumatology criteria from a low-incidence region for temporal arteritis. The results of our study are noteworthy, since there is limited data on pathologic diagnosis of temporal arteritis in Turkey. We studied the medical records, laboratory findings such as erythrocyte sedimentation rate and C-reactive protein levels, biopsy results, and postoperative complications of all the patients operated for temporal artery biopsy at our clinic. We used the computerized laboratory registry that keeps all records of 42 consecutive temporal artery biopsy results from January 2011 to December 2016. The mean age was 66±12.5 years. The most common manifestations on admission were temporal headache, optic neuritis and jaw claudication, respectively. Temporal artery biopsy  results confirmed tempoal arteritis in eight out of 42 (19%) patients. There was no statistically significant difference between biopsy-positive and biopsy-negative groups in terms of sex, age, erythrocyte sedimentation rate, C-reactive protein and biopsy length. We were not able to find a correlation between the analysis of biopsy results and clinical evaluation of patients with temporal arteritis. We suggest that diagnosis of temporal arteritis  depends on clinical suspicion. Laboratory examination results may not be helpful in accurate diagnosis of tempoal arteritis.

Outcome after temporal lobectomy in patients with medically-refractory mesial temporal epilepsy in Iran.

PubMed

Asadi-Pooya, Ali A; Rakei, Seyed M; Kamgarpour, Ahmad; Taghipour, Mousa; Ashjazadeh, Nahid; Razmkon, Ali; Zare, Zahra; Bagheri, Mohammad H

2017-06-01

Epilepsy surgery has been proved to be feasible and cost-effective in developing countries. In the current paper, we discussed the outcome of patients with mesial temporal lobe epilepsy (MTLE) and medically-refractory seizures who had surgery at our center in Shiraz, Iran. Patients aged 18 years and older with refractory MTLE and mesial temporal sclerosis operated at Namazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran from May 2009 through December 2011 were enrolled. Presurgical evaluation included clinical history, neurological examination, 2-hour video-EEG recording, and 1.5-T MRI. All patients were submitted to standard temporal lobectomy at the side determined by MRI and video-EEG. Twenty-two patients (12 women and 10 men) underwent surgery between May 2009 and December 2011. All patients were followed postoperatively for at least 12 months (mean=24.8±7.7 months; minimum=12 months; maximum=36 months). At the last follow-up visit, 18 patients (81.8%) had a good outcome (15 patients [68.2%] had Engel class 1 and three others had Engel class 2). The total cost of presurgical evaluation and epilepsy surgery at our center was less than $500. Resources are limited for the vast majority of medically-refractory patients with epilepsy who live in the developing countries. However, it is feasible to select good surgical candidates for anterior temporal lobectomy relying on the clinical history and examination, MRI and interictal EEG. Broader application of epilepsy surgery should be encouraged in countries with limited financial resources.

Monolithic amplifier with stable, high resistance feedback element and method for fabricating the same

DOEpatents

O'Connor, Paul

1998-08-11

A monolithic amplifier includes a stable, high resistance feedback circuit and a dynamic bias circuit. The dynamic bias circuit is formed with active elements matched to those in the amplifier and feedback circuit to compensate for variations in the operating and threshold voltages thereby maintaining a stable resistance in the feedback circuit.

Temporal variability in chlorophyll fluorescence of back-reef corals in Ofu, American Samoa

USGS Publications Warehouse

Piniak, G.A.; Brown, E.K.

2009-01-01

Change in the yield of chlorophyll a fluorescence is a common indicator of thermal stress in corals. The present study reports temporal variability in quantum yield measurements for 10 coral species in Ofu, American Samoa - a place known to experience elevated and variable seawater temperatures. In winter, the zooxanthellae generally had higher dark-adapted maximum quantum yield (F v/Fm), higher light- adapted effective quantum yield (??F/F'm), and lower relative electron transport rates (rETR) than in the summer. Temporal changes appeared unrelated to the expected bleaching sensitivity of corals. All species surveyed, with the exception of Montipora grisea, demonstrated significant temporal changes in the three fluorescence parameters. Fluorescence responses were influenced by the microhabitat - temporal differences in fluorescence parameters were usually observed in the habitat with a more variable temperature regime (pool 300), while differences in Fv/Fm between species were observed only in the more environmentally stable habitat (pool 400). Such species-specific responses and microhabitat variability should be considered when attempting to determine whether observed in situ changes are normal seasonal changes or early signs of bleaching. ?? 2009 Marine Biological Laboratory.

Temporal scaling and spatial statistical analyses of groundwater level fluctuations

NASA Astrophysics Data System (ADS)

Sun, H.; Yuan, L., Sr.; Zhang, Y.

2017-12-01

Natural dynamics such as groundwater level fluctuations can exhibit multifractionality and/or multifractality due likely to multi-scale aquifer heterogeneity and controlling factors, whose statistics requires efficient quantification methods. This study explores multifractionality and non-Gaussian properties in groundwater dynamics expressed by time series of daily level fluctuation at three wells located in the lower Mississippi valley, after removing the seasonal cycle in the temporal scaling and spatial statistical analysis. First, using the time-scale multifractional analysis, a systematic statistical method is developed to analyze groundwater level fluctuations quantified by the time-scale local Hurst exponent (TS-LHE). Results show that the TS-LHE does not remain constant, implying the fractal-scaling behavior changing with time and location. Hence, we can distinguish the potentially location-dependent scaling feature, which may characterize the hydrology dynamic system. Second, spatial statistical analysis shows that the increment of groundwater level fluctuations exhibits a heavy tailed, non-Gaussian distribution, which can be better quantified by a Lévy stable distribution. Monte Carlo simulations of the fluctuation process also show that the linear fractional stable motion model can well depict the transient dynamics (i.e., fractal non-Gaussian property) of groundwater level, while fractional Brownian motion is inadequate to describe natural processes with anomalous dynamics. Analysis of temporal scaling and spatial statistics therefore may provide useful information and quantification to understand further the nature of complex dynamics in hydrology.

Spatial and Temporal Mapping of Distributed Surface and Groundwater Stable Isotopes Enables New insights into Hydrologic Processes Operating at the Catchment Scale

NASA Astrophysics Data System (ADS)

Cole, A.; Boutt, D. F.

2017-12-01

Isotopic analyses of d18O and d2H of water transiting the hydrologic cycle have allowed hydrologists to better understand the portioning of water between the different components of the water cycle. Isoscapes on a large spatial scale have been created to show isotopic variation in waters as a function of elevation, temperature, distance to coast and precipitation. This has not been done on a 10,000 sq mi area, sub-regional scale or for that matter exhaustively sampled the important components of the terrestrial hydrologic cycle (groundwater, surface water and soil waters). We present the spatial and temporal isotopic results of an ongoing study across Massachusetts, USA, to establish an isotopic baseline for the region. Our current database consists of water samples from 50 precipitation sites, 333 ground water sites and 421 surface water sites. The isotopic signature of d18O and d2H of the samples are measured by a wavelength scanned cavity ring-down spectrometry on un-acidified water samples by a Picarro Cavity Ring Down Spectrometer (L2120-I) analyzer. Our results show that groundwater ranges from -11 to -1 ‰ δ18O across Massachusetts. Wells show a correlation with elevation; at higher elevations groundwater is more depleted in the heavy isotopes than compared with wells located at a lower elevation. Surface, groundwater and precipitation depict a seasonal evaporative enrichment, with waters being lighter during the months and heavier during the summer months. Based on Massachusetts location relative to the coast, there is a large variability in the mean d18O of precipitation with rain being heavy near the coast and lighter with increasing distance from the coast. HYSPLIT trajectory models will be used to determine how source affects isotopic composition. Within Massachusetts the isotopic composition of groundwater in till, glacial fluvial and bedrock aquifers are distinct which indicates the potential for surface and groundwater interaction. Our data also

Development of new S-band RF window for stable high-power operation in linear accelerator RF system

NASA Astrophysics Data System (ADS)

Joo, Youngdo; Lee, Byung-Joon; Kim, Seung-Hwan; Kong, Hyung-Sup; Hwang, Woonha; Roh, Sungjoo; Ryu, Jiwan

2017-09-01

For stable high-power operation, a new RF window is developed in the S-band linear accelerator (Linac) RF systems of the Pohang Light Source-II (PLS-II) and the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL). The new RF window is designed to mitigate the strength of the electric field at the ceramic disk and also at the waveguide-cavity coupling structure of the conventional RF window. By replacing the pill-box type cavity in the conventional RF window with an overmoded cavity, the electric field component perpendicular to the ceramic disk that caused most of the multipacting breakdowns in the ceramic disk was reduced by an order of magnitude. The reduced electric field at the ceramic disk eliminated the Ti-N coating process on the ceramic surface in the fabrication procedure of the new RF window, preventing the incomplete coating from spoiling the RF transmission and lowering the fabrication cost. The overmoded cavity was coupled with input and output waveguides through dual side-wall coupling irises to reduce the electric field strength at the waveguide-cavity coupling structure and the possibility of mode competitions in the overmoded cavity. A prototype of the new RF window was fabricated and fully tested with the Klystron peak input power, pulse duration and pulse repetition rate of 75 MW, 4.5 μs and 10 Hz, respectively, at the high-power test stand. The first mass-produced new RF window installed in the PLS-II Linac is running in normal operation mode. No fault is reported to date. Plans are being made to install the new RF window to all S-band accelerator RF modules of the PLS-II and PAL-XFEL Linacs. This new RF window may be applied to the output windows of S-band power sources like Klystron as wells as the waveguide windows of accelerator facilities which operate in S-band.

Depression-Biased Reverse Plasticity Rule Is Required for Stable Learning at Top-Down Connections

PubMed Central

Burbank, Kendra S.; Kreiman, Gabriel

2012-01-01

Top-down synapses are ubiquitous throughout neocortex and play a central role in cognition, yet little is known about their development and specificity. During sensory experience, lower neocortical areas are activated before higher ones, causing top-down synapses to experience a preponderance of post-synaptic activity preceding pre-synaptic activity. This timing pattern is the opposite of that experienced by bottom-up synapses, which suggests that different versions of spike-timing dependent synaptic plasticity (STDP) rules may be required at top-down synapses. We consider a two-layer neural network model and investigate which STDP rules can lead to a distribution of top-down synaptic weights that is stable, diverse and avoids strong loops. We introduce a temporally reversed rule (rSTDP) where top-down synapses are potentiated if post-synaptic activity precedes pre-synaptic activity. Combining analytical work and integrate-and-fire simulations, we show that only depression-biased rSTDP (and not classical STDP) produces stable and diverse top-down weights. The conclusions did not change upon addition of homeostatic mechanisms, multiplicative STDP rules or weak external input to the top neurons. Our prediction for rSTDP at top-down synapses, which are distally located, is supported by recent neurophysiological evidence showing the existence of temporally reversed STDP in synapses that are distal to the post-synaptic cell body. PMID:22396630

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

Monolithic amplifier with stable, high resistance feedback element and method for fabricating the same

DOEpatents

O`Connor, P.

1998-08-11

A monolithic amplifier includes a stable, high resistance feedback circuit and a dynamic bias circuit. The dynamic bias circuit is formed with active elements matched to those in the amplifier and feedback circuit to compensate for variations in the operating and threshold voltages thereby maintaining a stable resistance in the feedback circuit. 11 figs.

Higher order temporal finite element methods through mixed formalisms.

PubMed

Kim, Jinkyu

2014-01-01

The extended framework of Hamilton's principle and the mixed convolved action principle provide new rigorous weak variational formalism for a broad range of initial boundary value problems in mathematical physics and mechanics. In this paper, their potential when adopting temporally higher order approximations is investigated. The classical single-degree-of-freedom dynamical systems are primarily considered to validate and to investigate the performance of the numerical algorithms developed from both formulations. For the undamped system, all the algorithms are symplectic and unconditionally stable with respect to the time step. For the damped system, they are shown to be accurate with good convergence characteristics.

Space Technology 5 (ST-5) Observations of Field-Aligned Currents: Temporal Variability

NASA Technical Reports Server (NTRS)

Le, Guan

2010-01-01

Space Technology 5 (ST-5) is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, sun-synchronous polar orbit from March 22 to June 21, 2006, for technology validations. In this paper, we present a study of the temporal variability of field-aligned currents using multi-point magnetic field measurements from STS. The data demonstrate that masoscale current structures are commonly embedded within large-scale field-aligned current sheets. The meso-scale current structures are very dynamic with highly variable current density and/or polarity in time scales of about 10 min. They exhibit large temporal variations during both quiet and disturbed times in such time scales. On the other hand, the data also shown that the time scales for the currents to be relatively stable are about I min for meso-scale currents and about 10 min for large scale current sheets. These temporal features are obviously associated with dynamic variations of their particle carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of meso-scale field-aligned currents are found to be consistent with those of auroral parallel electric field.

Stable and simple quantitative phase-contrast imaging by Fresnel biprism

NASA Astrophysics Data System (ADS)

Ebrahimi, Samira; Dashtdar, Masoomeh; Sánchez-Ortiga, Emilio; Martínez-Corral, Manuel; Javidi, Bahram

2018-03-01

Digital holographic (DH) microscopy has grown into a powerful nondestructive technique for the real-time study of living cells including dynamic membrane changes and cell fluctuations in nanometer and sub-nanometer scales. The conventional DH microscopy configurations require a separately generated coherent reference wave that results in a low phase stability and a necessity to precisely adjust the intensity ratio between two overlapping beams. In this work, we present a compact, simple, and very stable common-path DH microscope, employing a self-referencing configuration. The microscope is implemented by a diode laser as the source and a Fresnel biprism for splitting and recombining the beams simultaneously. In the overlapping area, linear interference fringes with high contrast are produced. The frequency of the interference pattern could be easily adjusted by displacement of the biprism along the optical axis without a decrease in fringe contrast. To evaluate the validity of the method, the spatial noise and temporal stability of the setup are compared with the common off-axis DH microscope based on a Mach-Zehnder interferometer. It is shown that the proposed technique has low mechanical noise as well as superb temporal stability with sub-nanometer precision without any external vibration isolation. The higher temporal stability improves the capabilities of the microscope for studying micro-object fluctuations, particularly in the case of biological specimens. Experimental results are presented using red blood cells and silica microspheres to demonstrate the system performance.

Temporal nonlocality in bistable perception

NASA Astrophysics Data System (ADS)

Atmanspacher, Harald; Filk, Thomas

2012-12-01

A novel conceptual framework for theoretical psychology is presented and illustrated for the example of bistable perception. A basic formal feature of this framework is the non-commutativity of operations acting on mental states. A corresponding model for the bistable perception of ambiguous stimuli, the Necker-Zeno model, is sketched and some empirical evidence for it so far is described. It is discussed how a temporal nonlocality of mental states, predicted by the model, can be understood and tested.

Auditory temporal processing in patients with temporal lobe epilepsy.

PubMed

Lavasani, Azam Navaei; Mohammadkhani, Ghassem; Motamedi, Mahmoud; Karimi, Leyla Jalilvand; Jalaei, Shohreh; Shojaei, Fereshteh Sadat; Danesh, Ali; Azimi, Hadi

2016-07-01

Auditory temporal processing is the main feature of speech processing ability. Patients with temporal lobe epilepsy, despite their normal hearing sensitivity, may present speech recognition disorders. The present study was carried out to evaluate the auditory temporal processing in patients with unilateral TLE. The present study was carried out on 25 patients with epilepsy: 11 patients with right temporal lobe epilepsy and 14 with left temporal lobe epilepsy with a mean age of 31.1years and 18 control participants with a mean age of 29.4years. The two experimental and control groups were evaluated via gap-in-noise and duration pattern sequence tests. One-way ANOVA was run to analyze the data. The mean of the threshold of the GIN test in the control group was observed to be better than that in participants with LTLE and RTLE. Also, it was observed that the percentage of correct responses on the DPS test in the control group and in participants with RTLE was better than that in participants with LTLE. Patients with TLE have difficulties in temporal processing. Difficulties are more significant in patients with LTLE, likely because the left temporal lobe is specialized for the processing of temporal information. Copyright © 2016 Elsevier Inc. All rights reserved.

Entropy Stable Staggered Grid Spectral Collocation for the Burgers' and Compressible Navier-Stokes Equations

NASA Technical Reports Server (NTRS)

Carpenter, Mark H.; Parsani, Matteo; Fisher, Travis C.; Nielsen, Eric J.

2015-01-01

Staggered grid, entropy stable discontinuous spectral collocation operators of any order are developed for Burgers' and the compressible Navier-Stokes equations on unstructured hexahedral elements. This generalization of previous entropy stable spectral collocation work [1, 2], extends the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to a combination of tensor product Legendre-Gauss (LG) and LGL points. The new semi-discrete operators discretely conserve mass, momentum, energy and satisfy a mathematical entropy inequality for both Burgers' and the compressible Navier-Stokes equations in three spatial dimensions. They are valid for smooth as well as discontinuous flows. The staggered LG and conventional LGL point formulations are compared on several challenging test problems. The staggered LG operators are significantly more accurate, although more costly to implement. The LG and LGL operators exhibit similar robustness, as is demonstrated using test problems known to be problematic for operators that lack a nonlinearly stability proof for the compressible Navier-Stokes equations (e.g., discontinuous Galerkin, spectral difference, or flux reconstruction operators).

Development of technical solutions for securing stable operation of the intermediate separation and steam reheating system for the K-1000-60/3000 turbine unit

NASA Astrophysics Data System (ADS)

Trifonov, N. N.; Kovalenko, E. V.; Nikolaenkova, E. K.; Tren'kin, V. B.

2012-09-01

The intermediate separation and steam reheating system and its equipment are described. Problems concerned with the presence of condensate in the stack's lower chamber and in the removing chamber, with cavitation failure of the separated moisture pumps, with misalignment of heating steam flowrates, with unstable draining of heating steam condensate, with occurrence of self oscillations, etc. are considered. A procedure for determining the level in removing heating steam condensate from steam reheater elements is proposed. Technical solutions for ensuring stable operation of the intermediate separation and steam reheating system and for achieving smaller misalignment between the apparatuses are developed.

Spatial pattern and temporal trend of mortality due to tuberculosis 10

PubMed Central

de Queiroz, Ana Angélica Rêgo; Berra, Thaís Zamboni; Garcia, Maria Concebida da Cunha; Popolin, Marcela Paschoal; Belchior, Aylana de Souza; Yamamura, Mellina; dos Santos, Danielle Talita; Arroyo, Luiz Henrique; Arcêncio, Ricardo Alexandre

2018-01-01

ABSTRACT Objectives: To describe the epidemiological profile of mortality due to tuberculosis (TB), to analyze the spatial pattern of these deaths and to investigate the temporal trend in mortality due to tuberculosis in Northeast Brazil. Methods: An ecological study based on secondary mortality data. Deaths due to TB were included in the study. Descriptive statistics were calculated and gross mortality rates were estimated and smoothed by the Local Empirical Bayesian Method. Prais-Winsten’s regression was used to analyze the temporal trend in the TB mortality coefficients. The Kernel density technique was used to analyze the spatial distribution of TB mortality. Results: Tuberculosis was implicated in 236 deaths. The burden of tuberculosis deaths was higher amongst males, single people and people of mixed ethnicity, and the mean age at death was 51 years. TB deaths were clustered in the East, West and North health districts, and the tuberculosis mortality coefficient remained stable throughout the study period. Conclusions: Analyses of the spatial pattern and temporal trend in mortality revealed that certain areas have higher TB mortality rates, and should therefore be prioritized in public health interventions targeting the disease. PMID:29742272

Spontaneous switching among multiple spatio-temporal patterns in three-oscillator systems constructed with oscillatory cells of true slime mold

NASA Astrophysics Data System (ADS)

Takamatsu, Atsuko

2006-11-01

Three-oscillator systems with plasmodia of true slime mold, Physarum polycephalum, which is an oscillatory amoeba-like unicellular organism, were experimentally constructed and their spatio-temporal patterns were investigated. Three typical spatio-temporal patterns were found: rotation ( R), partial in-phase ( PI), and partial anti-phase with double frequency ( PA). In pattern R, phase differences between adjacent oscillators were almost 120 ∘. In pattern PI, two oscillators were in-phase and the third oscillator showed anti-phase against the two oscillators. In pattern PA, two oscillators showed anti-phase and the third oscillator showed frequency doubling oscillation with small amplitude. Actually each pattern is not perfectly stable but quasi-stable. Interestingly, the system shows spontaneous switching among the multiple quasi-stable patterns. Statistical analyses revealed a characteristic in the residence time of each pattern: the histograms seem to have Gamma-like distribution form but with a sharp peak and a tail on the side of long period. That suggests the attractor of this system has complex structure composed of at least three types of sub-attractors: a “Gamma attractor”-involved with several Poisson processes, a “deterministic attractor”-the residence time is deterministic, and a “stable attractor”-each pattern is stable. When the coupling strength was small, only the Gamma attractor was observed and switching behavior among patterns R, PI, and PA almost always via an asynchronous pattern named O. A conjecture is as follows: Internal/external noise exposes each pattern of R, PI, and PA coexisting around bifurcation points: That is observed as the Gamma attractor. As coupling strength increases, the deterministic attractor appears then followed by the stable attractor, always accompanied with the Gamma attractor. Switching behavior could be caused by regular existence of the Gamma attractor.

Fibrous Dysplasia of the Temporal Bone with External Auditory Canal Stenosis and Secondary Cholesteatoma.

PubMed

Liu, Yu-Hsi; Chang, Kuo-Ping

2016-04-01

Fibrous dysplasia is a slowly progressive benign fibro-osseous disease, rarely occurring in temporal bones. In these cases, most bony lesions developed from the bony part of the external auditory canals, causing otalgia, hearing impairment, otorrhea, and ear hygiene blockade and probably leading to secondary cholesteatoma. We presented the medical history of a 24-year-old woman with temporal monostotic fibrous dysplasia with secondary cholesteatoma. The initial presentation was unilateral conductive hearing loss. A hard external canal tumor contributing to canal stenosis and a near-absent tympanic membrane were found. Canaloplasty and type I tympanoplasty were performed, but the symptoms recurred after 5 years. She received canal wall down tympanomastoidectomy with ossciculoplasty at the second time, and secondary cholesteatoma in the middle ear was diagnosed. Fifteen years later, left otorrhea recurred again and transcanal endoscopic surgery was performed for middle ear clearance. Currently, revision surgeries provide a stable auditory condition, but her monostotic temporal fibrous dysplasia is still in place.

EXAMINING THE TEMPORAL VARIABILITY OF AMMONIA AND NITRIC OXIDE EMISSIONS FROM AGRICULTURAL PROCESSES

EPA Science Inventory

This paper examines the temporal variability of airborne emissions of ammonia from livestock operations and fertilizer application and nitric oxide from soils. In the United States, the livestock operations and fertilizer categories comprise the majority of the ammonia emissions...

Elevated CO2 and water addition enhance nitrogen turnover in grassland plants with implications for temporal stability.

PubMed

Dijkstra, Feike A; Carrillo, Yolima; Blumenthal, Dana M; Mueller, Kevin E; LeCain, Dan R; Morgan, Jack A; Zelikova, Tamara J; Williams, David G; Follett, Ronald F; Pendall, Elise

2018-05-01

Temporal variation in soil nitrogen (N) availability affects growth of grassland communities that differ in their use and reuse of N. In a 7-year-long climate change experiment in a semi-arid grassland, the temporal stability of plant biomass production varied with plant N turnover (reliance on externally acquired N relative to internally recycled N). Species with high N turnover were less stable in time compared to species with low N turnover. In contrast, N turnover at the community level was positively associated with asynchrony in biomass production, which in turn increased community temporal stability. Elevated CO 2 and summer irrigation, but not warming, enhanced community N turnover and stability, possibly because treatments promoted greater abundance of species with high N turnover. Our study highlights the importance of plant N turnover for determining the temporal stability of individual species and plant communities affected by climate change. © 2018 John Wiley & Sons Ltd/CNRS.

Inclusion of temporal priors for automated neonatal EEG classification

NASA Astrophysics Data System (ADS)

Temko, Andriy; Stevenson, Nathan; Marnane, William; Boylan, Geraldine; Lightbody, Gordon

2012-08-01

The aim of this paper is to use recent advances in the clinical understanding of the temporal evolution of seizure burden in neonates with hypoxic ischemic encephalopathy to improve the performance of automated detection algorithms. Probabilistic weights are designed from temporal locations of neonatal seizure events relative to time of birth. These weights are obtained by fitting a skew-normal distribution to the temporal seizure density and introduced into the probabilistic framework of the previously developed neonatal seizure detector. The results are validated on the largest available clinical dataset, comprising 816.7 h. By exploiting these priors, the receiver operating characteristic area is increased by 23% (relative) reaching 96.74%. The number of false detections per hour is decreased from 0.45 to 0.25, while maintaining the correct detection of seizure burden at 70%.

Visualization of Spatio-Temporal Relations in Movement Event Using Multi-View

NASA Astrophysics Data System (ADS)

Zheng, K.; Gu, D.; Fang, F.; Wang, Y.; Liu, H.; Zhao, W.; Zhang, M.; Li, Q.

2017-09-01

Spatio-temporal relations among movement events extracted from temporally varying trajectory data can provide useful information about the evolution of individual or collective movers, as well as their interactions with their spatial and temporal contexts. However, the pure statistical tools commonly used by analysts pose many difficulties, due to the large number of attributes embedded in multi-scale and multi-semantic trajectory data. The need for models that operate at multiple scales to search for relations at different locations within time and space, as well as intuitively interpret what these relations mean, also presents challenges. Since analysts do not know where or when these relevant spatio-temporal relations might emerge, these models must compute statistical summaries of multiple attributes at different granularities. In this paper, we propose a multi-view approach to visualize the spatio-temporal relations among movement events. We describe a method for visualizing movement events and spatio-temporal relations that uses multiple displays. A visual interface is presented, and the user can interactively select or filter spatial and temporal extents to guide the knowledge discovery process. We also demonstrate how this approach can help analysts to derive and explain the spatio-temporal relations of movement events from taxi trajectory data.

Transformation of temporal sequences in the zebra finch auditory system

PubMed Central

Lim, Yoonseob; Lagoy, Ryan; Shinn-Cunningham, Barbara G; Gardner, Timothy J

2016-01-01

This study examines how temporally patterned stimuli are transformed as they propagate from primary to secondary zones in the thalamorecipient auditory pallium in zebra finches. Using a new class of synthetic click stimuli, we find a robust mapping from temporal sequences in the primary zone to distinct population vectors in secondary auditory areas. We tested whether songbirds could discriminate synthetic click sequences in an operant setup and found that a robust behavioral discrimination is present for click sequences composed of intervals ranging from 11 ms to 40 ms, but breaks down for stimuli composed of longer inter-click intervals. This work suggests that the analog of the songbird auditory cortex transforms temporal patterns to sequence-selective population responses or ‘spatial codes', and that these distinct population responses contribute to behavioral discrimination of temporally complex sounds. DOI: http://dx.doi.org/10.7554/eLife.18205.001 PMID:27897971

Temporally variable environments maintain more beta-diversity in Mediterranean landscapes

NASA Astrophysics Data System (ADS)

Martin, Beatriz; Ferrer, Miguel

2015-10-01

We examined the relationships between different environmental factors and the alpha and beta-diversity of terrestrial vertebrates (birds, mammals, amphibians and reptiles) in a Mediterranean region at the landscape level. We investigated whether the mechanisms underlying alpha and beta-diversity patterns are influenced by energy availability, habitat heterogeneity and temporal variability and if the drivers of the diversity patterns differed between both components of diversity. We defined alpha-diversity as synonym of species richness whereas beta-diversity was measured as distinctiveness. We evaluated a total of 13 different predictors using generalized linear mixed model (GLMM) analysis. Habitat spatial heterogeneity increased alpha-diversity, but contrastingly, it did not significantly affect beta-diversity among sites. Disturbed landscapes may show higher habitat spatial variation and higher alpha-diversity due to the contribution of highly generalist species that are wide-distributed and do not differ in composition (beta-diversity) among different sites within the region. Contrastingly, higher beta-diversity levels were negatively related to more stable sites in terms of temporal environmental variation. This negative relationship between environmental stability and beta-diversity levels is explained in terms of species adaptation to the local environmental conditions. Our study highlights the importance of temporal environmental variability in maintaining beta-diversity patterns under highly variable environmental conditions.

Temporal changes in the bacterial community of animal feces and their correlation with stable fly oviposition, larval development, and adult fitness

PubMed Central

Albuquerque, Thais A.; Zurek, Ludek

2014-01-01

Stable flies are blood-feeding insects with a great negative impact on animals world wide. Larvae develop primarily in animal manure and bacteria are essential for larval development; however, the principle of this dependence is not understood. We hypothesized that as the microbial community of animal manure changes over time, it plays an important role in stable fly fitness. Two-choice bioassays were conducted using 2 week old horse manure (control) and aging horse manure (fresh to 5 week old) to evaluate the effect of manure age on stable fly oviposition. Our data showed that fresh feces did not stimulate oviposition and that the attractiveness increased as manure aged but started to decline after 3 weeks. Bioassays assessing the effect of manure age at the time of oviposition on larval development demonstrated that 1–3 week old manure supported larval development significantly better than fresh, 4, and 5 week old manure. In addition, adult fitness (body size) was significantly higher in flies from 1 and 2 week old manure comparing to that of all other treatments. Analysis of the bacterial community of aging horse manure by 454-pyrosequencing of 16S rDNA revealed a great reduction in bacterial diversity and richness from fresh to 1–5 week old manure and a major shift from strict anaerobes in fresh manure to facultative anaerobes and strict aerobes in aged manure. Overall, the microbial community of 2 and 3 week old horse manure with its dominant bacterial taxa Rhizobium, Devosia, and Brevundimonas stimulated stable fly oviposition the most and provided a suitable habitat for larval development. These bacteria represent the candidates for studies focused on better understanding of stable fly – microbial interactions. PMID:25426108

Histological findings in two renal transplants accomplishing operational tolerance criteria.

PubMed

Azancot, M A; Moreso, F; Cantarell, C; Torres, I B; Serón, D R

2011-06-01

Operational tolerance is defined as stable renal function in transplants without immunosuppression for at least 1 year. We present histological assessments of two patients with operational tolerance. The first withdrew immunosuppression in 2005 and presents stable renal function (creatinine 1.5 mg/dL) without proteinuria. The biopsy showed mild chronic tubulointerstitial changes without inflammation. The second withdrew immunosuppression in 2009 and maintains stable renal function (creatinine 1.6 mg/dL) with mild proteinuria. Histology showed chronic humoural rejection and Class II anti-human leukocyte antigen antibodies were detected. These cases suggest that a renal biopsy may be useful to rule out subclinical pathology in patients with operational tolerance.

Strong Temporal Variation Over One Saturnian Year: From Voyager to Cassini

NASA Technical Reports Server (NTRS)

Li, Liming; Achterberg, Richard K.; Conrath, Barney J.; Gierasch, Peter J.; Smith, Mark A.; Simon-Miller, Amy A.; Nixon, Conor A.; Orton, Glenn S.; Flasar, F. Michael; Jiang, Xun;

Strong Temporal Variation Over One Saturnian Year: From Voyager to Cassini

PubMed Central

Li, Liming; Achterberg, Richard K.; Conrath, Barney J.; Gierasch, Peter J.; Smith, Mark A.; Simon-Miller, Amy A.; Nixon, Conor A.; Orton, Glenn S.; Flasar, F. Michael; Jiang, Xun; Baines, Kevin H.; Morales-Juberías, Raúl; Ingersoll, Andrew P.; Vasavada, Ashwin R.; Del Genio, Anthony D.; West, Robert A.; Ewald, Shawn P.

2013-01-01

Here we report the combined spacecraft observations of Saturn acquired over one Saturnian year (~29.5 Earth years), from the Voyager encounters (1980–81) to the new Cassini reconnaissance (2009–10). The combined observations reveal a strong temporal increase of tropic temperature (~10 Kelvins) around the tropopause of Saturn (i.e., 50 mbar), which is stronger than the seasonal variability (~a few Kelvins). We also provide the first estimate of the zonal winds at 750 mbar, which is close to the zonal winds at 2000 mbar. The quasi-consistency of zonal winds between these two levels provides observational support to a numerical suggestion inferring that the zonal winds at pressures greater than 500 mbar do not vary significantly with depth. Furthermore, the temporal variation of zonal winds decreases its magnitude with depth, implying that the relatively deep zonal winds are stable with time. PMID:23934437

Space Technology 5 Multipoint Observations of Temporal and Spatial Variability of Field-Aligned Currents

NASA Technical Reports Server (NTRS)

Le, G.; Wang, Y.; Slavin, J. A.; Strangeway, R. L.

2009-01-01

Space Technology 5 (ST5) is a constellation mission consisting of three microsatellites. It provides the first multipoint magnetic field measurements in low Earth orbit, which enables us to separate spatial and temporal variations. In this paper, we present a study of the temporal variability of field-aligned currents using the ST5 data. We examine the field-aligned current observations during and after a geomagnetic storm and compare the magnetic field profiles at the three spacecraft. The multipoint data demonstrate that mesoscale current structures, commonly embedded within large-scale current sheets, are very dynamic with highly variable current density and/or polarity in approx.10 min time scales. On the other hand, the data also show that the time scales for the currents to be relatively stable are approx.1 min for mesoscale currents and approx.10 min for large-scale currents. These temporal features are very likely associated with dynamic variations of their charge carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of mesoscale field-aligned currents are found to be consistent with those of auroral parallel electric field.

Temporal Variability in the Deglutition Literature

PubMed Central

Molfenter, Sonja M.; Steele, Catriona M.

2013-01-01

A literature review was conducted on temporal measures of swallowing in healthy individuals with the purpose of determining the degree of variability present in such measures within the literature. A total of 46 studies that met inclusion criteria were reviewed. The definitions and descriptive statistics for all reported temporal parameters were compiled for meta-analysis. In total, 119 different temporal parameters were found in the literature. The three most-frequently occurring durational measures were: UES opening, laryngeal closure and hyoid movement. The three most-frequently occurring interval measures were: stage transition duration, pharyngeal transit time and duration from laryngeal closure to UES opening. Subtle variations in operational definitions across studies were noted, making the comparison of data challenging. Analysis of forest plots compiling descriptive statistical data (means and 95% confidence intervals) across studies revealed differing degrees of variability across durations and intervals. Two parameters (UES opening duration and the laryngeal-closure-to-UES-opening interval) demonstrated the least variability, reflected by small ranges for mean values and tight confidence intervals. Trends emerged for factors of bolus size and participant age for some variables. Other potential sources of variability are discussed. PMID:22366761

Temporal variation in stable isotopes ( 18O and 2H) and major ion concentrations within the Darling River between Bourke and Wilcannia due to variable flows, saline groundwater influx and evaporation

NASA Astrophysics Data System (ADS)

Meredith, K. T.; Hollins, S. E.; Hughes, C. E.; Cendón, D. I.; Hankin, S.; Stone, D. J. M.

2009-11-01

SummaryThe Darling River faces environmental pressures from both climate change and anthropogenic influences leading to a reduction in fresh water availability for the river system. This study uses temporal hydrochemical and stable isotope data ( 18O and 2H) that has been collected over a five-year period (2002 to 2007), as part of the Global Network for Isotopes in Rivers (GNIR) programme, which is aimed at monitoring hydrological processes in large river systems throughout the world. Daily stream flow, monthly stable isotope and major ion chemistry data is presented for sampling locations along the Darling River at Bourke, Louth and Wilcannia, as well as additional more detailed data from locations near Glen Villa. The hydrochemical data is used to partition groundwater influx that is not readily separable by using only the available isotopic data. Individual flow events in the river were found to be isotopically distinct but the Local Evaporation Lines (LELs) that develop after these events have a similar slope indicating similar climatic conditions across this region. After a storm event, fresh waters that are isotopically depleted are introduced to the system and d-excess ( d) values return towards meteoric values. During low flow, the Cl -, Na +, Mg 2+, SO 42-, δ 18O and δ 2H values all increase systematically, and d values become more negative. Hydrochemical and isotopic tracers in conjunction with high resolution sampling strategies have been used to quantify the contribution of evaporation, bank storage release and saline groundwater influx to the evolution of the river waters. Fractional contributions (% of volume) of groundwater to the river water were calculated for different reaches using Cl - concentrations, δ 18O and d values and it was found that river waters comprised of approximately 60-99% saline groundwater during zero flow. The reduced water levels in the river during the drought conditions experienced in the period of this study had

Integrating Time-Synchronized Video with Other Geospatial and Temporal Data for Remote Science Operations

NASA Technical Reports Server (NTRS)

Cohen, Tamar E.; Lees, David S.; Deans, Matthew C.; Lim, Darlene S. S.; Lee, Yeon Jin Grace

2018-01-01

Exploration Ground Data Systems (xGDS) supports rapid scientific decision making by synchronizing video in context with map, instrument data visualization, geo-located notes and any other collected data. xGDS is an open source web-based software suite developed at NASA Ames Research Center to support remote science operations in analog missions and prototype solutions for remote planetary exploration. (See Appendix B) Typical video systems are designed to play or stream video only, independent of other data collected in the context of the video. Providing customizable displays for monitoring live video and data as well as replaying recorded video and data helps end users build up a rich situational awareness. xGDS was designed to support remote field exploration with unreliable networks. Commercial digital recording systems operate under the assumption that there is a stable and reliable network between the source of the video and the recording system. In many field deployments and space exploration scenarios, this is not the case - there are both anticipated and unexpected network losses. xGDS' Video Module handles these interruptions, storing the available video, organizing and characterizing the dropouts, and presenting the video for streaming or replay to the end user including visualization of the dropouts. Scientific instruments often require custom or expensive software to analyze and visualize collected data. This limits the speed at which the data can be visualized and limits access to the data to those users with the software. xGDS' Instrument Module integrates with instruments that collect and broadcast data in a single snapshot or that continually collect and broadcast a stream of data. While seeing a visualization of collected instrument data is informative, showing the context for the collected data, other data collected nearby along with events indicating current status helps remote science teams build a better understanding of the environment

Brain regions underlying word finding difficulties in temporal lobe epilepsy.

PubMed

Trebuchon-Da Fonseca, Agnes; Guedj, Eric; Alario, F-Xavier; Laguitton, Virginie; Mundler, Olivier; Chauvel, Patrick; Liegeois-Chauvel, Catherine

2009-10-01

Word finding difficulties are often reported by epileptic patients with seizures originating from the language dominant cerebral hemisphere, for example, in temporal lobe epilepsy. Evidence regarding the brain regions underlying this deficit comes from studies of peri-operative electro-cortical stimulation, as well as post-surgical performance. This evidence has highlighted a role for the anterior part of the dominant temporal lobe in oral word production. These conclusions contrast with findings from activation studies involving healthy speakers or acute ischaemic stroke patients, where the region most directly related to word retrieval appears to be the posterior part of the left temporal lobe. To clarify the neural basis of word retrieval in temporal lobe epilepsy, we tested forty-three drug-resistant temporal lobe epilepsy patients (28 left, 15 right). Comprehensive neuropsychological and language assessments were performed. Single spoken word production was elicited with picture or definition stimuli. Detailed analysis allowed the distinction of impaired word retrieval from other possible causes of naming failure. Finally, the neural substrate of the deficit was assessed by correlating word retrieval performance and resting-state brain metabolism in 18 fluoro-2-deoxy-d-glucose-Positron Emission Tomography. Naming difficulties often resulted from genuine word retrieval failures (anomic states), both in picture and in definition tasks. Left temporal lobe epilepsy patients showed considerably worse performance than right temporal lobe epilepsy patients. Performance was poorer in the definition than in the picture task. Across patients and the left temporal lobe epilepsy subgroup, frequency of anomic state was negatively correlated with resting-state brain metabolism in left posterior and basal temporal regions (Brodmann's area 20-37-39). These results show the involvement of posterior temporal regions, within a larger antero-posterior-basal temporal network, in

On the habitability of universes without stable deuterium

NASA Astrophysics Data System (ADS)

Adams, Fred C.; Grohs, Evan

2017-05-01

In both stars and in the early universe, the production of deuterium is the first step on the way to producing heavier nuclei. If the strong force were slightly weaker, then deuterium would not be stable, and many authors have noted that nuclesynthesis would be compromised so that helium production could not proceed through standard reaction chains. Motivated by the possibility that other regions of space-time could have different values for the fundamental constants, this paper considers stellar evolution in universes without stable deuterium and argues that such universes can remain habitable. Even in universes with no stellar nucleosynthesis, stars can form and will generate energy through gravitational contraction. Using both analytic estimates and a state-of-the-art stellar evolution code, we show that such stars can be sufficiently luminous and long-lived to support life. Stars with initial masses that exceed the Chandrasekhar mass cannot be supported by degeneracy pressure and will explode at the end of their contraction phase. The resulting explosive nucleosynthesis can thus provide the universe with some heavy elements. We also explore the possibility that helium can be produced in stellar cores through a triple-nucleon reaction that is roughly analogous to the triple-alpha reaction that operates in our universe. Stars burning hydrogen through this process are somewhat hotter than those in our universe, but otherwise play the same role. Next we show that with even trace amounts (metallicity Z ∼10-10) of heavy elements - produced through the triple-nucleon process or by explosive nucleosynthesis - the CNO cycle can operate and allow stars to function. Finally, we consider Big Bang Nucleosynthesis without stable deuterium and find that only trace amounts of helium are produced, with even smaller abundances of other nuclei. With stars evolving through gravitational contraction, explosive nucleosynthesis, the triple-nucleon reaction, and the CNO cycle

Space Technology 5 Multi-Point Observations of Temporal Variability of Field-Aligned Currents

NASA Technical Reports Server (NTRS)

Le, Guan; Wang, Yongli; Slavin, James A.; Strangeway, Robert J.

2008-01-01

Space Technology 5 (ST5) is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, sun-synchronous polar orbit from March 22 to June 21, 2006, for technology validations. In this paper, we present a study of the temporal variability of field-aligned currents using multi-point magnetic field measurements from ST5. The data demonstrate that meso-scale current structures are commonly embedded within large-scale field-aligned current sheets. The meso-scale current structures are very dynamic with highly variable current density and/or polarity in time scales of approximately 10 min. They exhibit large temporal variations during both quiet and disturbed times in such time scales. On the other hand, the data also shown that the time scales for the currents to be relatively stable are approximately 1 min for meso-scale currents and approximately 10 min for large scale current sheets. These temporal features are obviously associated with dynamic variations of their particle carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of meso-scale field-aligned currents are found to be consistent with those of auroral parallel electric field.

A semiparametric spatio-temporal model for solar irradiance data

DOE PAGES

Patrick, Joshua D.; Harvill, Jane L.; Hansen, Clifford W.

2016-03-01

Here, we evaluate semiparametric spatio-temporal models for global horizontal irradiance at high spatial and temporal resolution. These models represent the spatial domain as a lattice and are capable of predicting irradiance at lattice points, given data measured at other lattice points. Using data from a 1.2 MW PV plant located in Lanai, Hawaii, we show that a semiparametric model can be more accurate than simple interpolation between sensor locations. We investigate spatio-temporal models with separable and nonseparable covariance structures and find no evidence to support assuming a separable covariance structure. These results indicate a promising approach for modeling irradiance atmore » high spatial resolution consistent with available ground-based measurements. Moreover, this kind of modeling may find application in design, valuation, and operation of fleets of utility-scale photovoltaic power systems.« less

Spatial and temporal relations in conditioned reinforcement and observing behavior

PubMed Central

Bowe, Craig A.; Dinsmoor, James A.

1983-01-01

In Experiment 1, depressing one perch produced stimuli indicating which of two keys, if pecked, could produce food (spatial information) and depressing the other perch produced stimuli indicating whether a variable-interval or an extinction schedule was operating (temporal information). The pigeons increased the time they spent depressing the perch that produced the temporal information but did not increase the time they spent depressing the perch that produced the spatial information. In Experiment 2, pigeons that were allowed to produce combined spatial and temporal information did not acquire the perch pressing any faster or maintain it at a higher level than pigeons allowed to produce only temporal information. Later, when perching produced only spatial information, the time spent depressing the perch eventually declined. The results are not those implied by the statement that information concerning biologically important events is reinforcing but are consistent with an interpretation in terms of the acquisition of reinforcing properties by a stimulus associated with a higher density of primary reinforcement. PMID:16812316

Status of stable isotope enrichment, products, and services at the Oak Ridge National Laboratory

NASA Astrophysics Data System (ADS)

Scott Aaron, W.; Tracy, Joe G.; Collins, Emory D.

1997-02-01

The Oak Ridge National Laboratory (ORNL) has been supplying enriched stable and radioactive isotopes to the research, medical, and industrial communities for over 50 y. Very significant changes have occurred in this effort over the past several years, and, while many of these changes have had a negative impact on the availability of enriched isotopes, more recent developments are actually improving the situation for both the users and the producers of enriched isotopes. ORNL is still a major producer and distributor of radioisotopes, but future isotope enrichment operations to be conducted at the Isotope Enrichment Facility (IEF) will be limited to stable isotopes. Among the positive changes in the enriched stable isotope area are a well-functioning, long-term contract program, which offers stability and pricing advantages; the resumption of calutron operations; the adoption of prorated conversion charges, which greatly improves the pricing of isotopes to small users; ISO 9002 registration of the IEF's quality management system; and a much more customer-oriented business philosophy. Efforts are also being made to restore and improve upon the extensive chemical and physical form processing capablities that once existed in the enriched stable isotope program. Innovative ideas are being pursued in both technical and administrative areas to encourage the beneficial use of enriched stable isotopes and the development of related technologies.

Identification, Attribution, and Quantification of Highly Heterogeneous Methane Sources Using a Mobile Stable Isotope Analyzer

NASA Astrophysics Data System (ADS)

Crosson, E.; Rella, C.; Cunningham, K.

2012-04-01

Despite methane's importance as a potent greenhouse gas second only to carbon dioxide in the magnitude of its contribution to global warming, natural contributions to the overall methane budget are only poorly understood. A big contributor to this gap in knowledge is the highly spatially and temporally heterogeneous nature of most natural (and for that matter anthropogenic) methane sources. This high degree of heterogeneity, where the methane emission rates can vary over many orders of magnitude on a spatial scale of meters or even centimeters, and over a temporal scale of minutes or even seconds, means that traditional methods of emissions flux estimation, such as flux chambers or eddy-covariance, are difficult or impossible to apply. In this paper we present new measurement methods that are capable of detecting, attributing, and quantifying emissions from highly heterogeneous sources. These methods take full advantage of the new class of methane concentration and stable isotope analyzers that are capable of laboratory-quality analysis from a mobile field platform in real time. In this paper we present field measurements demonstrating the real-time detection of methane 'hot spots,' attribution of the methane to a source process via real-time stable isotope analysis, and quantification of the emissions flux using mobile concentration measurements of the horizontal and vertical atmospheric dispersion, combined with atmospheric transport calculations. Although these techniques are applicable to both anthropogenic and natural methane sources, in this initial work we focus primarily on landfills and fugitive emissions from natural gas distribution, as these sources are better characterized, and because they provide a more reliable and stable source of methane for quantifying the measurement uncertainty inherent in the different methods. Implications of these new technologies and techniques are explored for the quantification of natural methane sources in a variety of

Brain connectivity analysis from EEG signals using stable phase-synchronized states during face perception tasks

NASA Astrophysics Data System (ADS)

Jamal, Wasifa; Das, Saptarshi; Maharatna, Koushik; Pan, Indranil; Kuyucu, Doga

2015-09-01

Degree of phase synchronization between different Electroencephalogram (EEG) channels is known to be the manifestation of the underlying mechanism of information coupling between different brain regions. In this paper, we apply a continuous wavelet transform (CWT) based analysis technique on EEG data, captured during face perception tasks, to explore the temporal evolution of phase synchronization, from the onset of a stimulus. Our explorations show that there exists a small set (typically 3-5) of unique synchronized patterns or synchrostates, each of which are stable of the order of milliseconds. Particularly, in the beta (β) band, which has been reported to be associated with visual processing task, the number of such stable states has been found to be three consistently. During processing of the stimulus, the switching between these states occurs abruptly but the switching characteristic follows a well-behaved and repeatable sequence. This is observed in a single subject analysis as well as a multiple-subject group-analysis in adults during face perception. We also show that although these patterns remain topographically similar for the general category of face perception task, the sequence of their occurrence and their temporal stability varies markedly between different face perception scenarios (stimuli) indicating toward different dynamical characteristics for information processing, which is stimulus-specific in nature. Subsequently, we translated these stable states into brain complex networks and derived informative network measures for characterizing the degree of segregated processing and information integration in those synchrostates, leading to a new methodology for characterizing information processing in human brain. The proposed methodology of modeling the functional brain connectivity through the synchrostates may be viewed as a new way of quantitative characterization of the cognitive ability of the subject, stimuli and information integration

Network Analysis of Foramen Ovale Electrode Recordings in Drug-resistant Temporal Lobe Epilepsy Patients

PubMed Central

Sanz-García, Ancor; Vega-Zelaya, Lorena; Pastor, Jesús; Torres, Cristina V.; Sola, Rafael G.; Ortega, Guillermo J.

2016-01-01

Approximately 30% of epilepsy patients are refractory to antiepileptic drugs. In these cases, surgery is the only alternative to eliminate/control seizures. However, a significant minority of patients continues to exhibit post-operative seizures, even in those cases in which the suspected source of seizures has been correctly localized and resected. The protocol presented here combines a clinical procedure routinely employed during the pre-operative evaluation of temporal lobe epilepsy (TLE) patients with a novel technique for network analysis. The method allows for the evaluation of the temporal evolution of mesial network parameters. The bilateral insertion of foramen ovale electrodes (FOE) into the ambient cistern simultaneously records electrocortical activity at several mesial areas in the temporal lobe. Furthermore, network methodology applied to the recorded time series tracks the temporal evolution of the mesial networks both interictally and during the seizures. In this way, the presented protocol offers a unique way to visualize and quantify measures that considers the relationships between several mesial areas instead of a single area. PMID:28060326

Atherosclerotic plaque characterization by spatial and temporal speckle pattern analysis

NASA Astrophysics Data System (ADS)

Tearney, Guillermo J.; Bouma, Brett E.

2002-04-01

Improved methods are needed to identify the vulnerable coronary plaques responsible for acute myocardial infraction or sudden cardiac death. We describe a method for characterizing the structure and biomechanical properties of atherosclerotic plaques based on speckle pattern fluctuations. Near-field speckle images were acquired from five human aortic specimens ex vivo. The speckle decorrelation time constant varied significantly for vulnerable aortic plaques (τ = 40 ms) versus stable plaques (τ = 400 ms) and normal aorta (τ = 500 ms). These initial results indicate that different atherosclerotic plaque types may be distinguished by analysis of temporal and spatial speckle pattern fluctuations.

Temporal variability of the bioaerosol background at a subway station: concentration level, size distribution, and diversity of airborne bacteria.

PubMed

Dybwad, Marius; Skogan, Gunnar; Blatny, Janet Martha

2014-01-01

Naturally occurring bioaerosol environments may present a challenge to biological detection-identification-monitoring (BIODIM) systems aiming at rapid and reliable warning of bioterrorism incidents. One way to improve the operational performance of BIODIM systems is to increase our understanding of relevant bioaerosol backgrounds. Subway stations are enclosed public environments which may be regarded as potential bioterrorism targets. This study provides novel information concerning the temporal variability of the concentration level, size distribution, and diversity of airborne bacteria in a Norwegian subway station. Three different air samplers were used during a 72-h sampling campaign in February 2011. The results suggested that the airborne bacterial environment was stable between days and seasons, while the intraday variability was found to be substantial, although often following a consistent diurnal pattern. The bacterial levels ranged from not detected to 10(3) CFU m(-3) and generally showed increased levels during the daytime compared to the nighttime levels, as well as during rush hours compared to non-rush hours. The airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly passengers) were demonstrated as major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. Our findings contribute to the development of realistic testing and evaluation schemes for BIODIM equipment by providing information that may be used to simulate operational bioaerosol backgrounds during controlled aerosol chamber-based challenge tests with biological threat agents.

Temporal Variability of the Bioaerosol Background at a Subway Station: Concentration Level, Size Distribution, and Diversity of Airborne Bacteria

PubMed Central

Dybwad, Marius; Skogan, Gunnar

2014-01-01

Naturally occurring bioaerosol environments may present a challenge to biological detection-identification-monitoring (BIODIM) systems aiming at rapid and reliable warning of bioterrorism incidents. One way to improve the operational performance of BIODIM systems is to increase our understanding of relevant bioaerosol backgrounds. Subway stations are enclosed public environments which may be regarded as potential bioterrorism targets. This study provides novel information concerning the temporal variability of the concentration level, size distribution, and diversity of airborne bacteria in a Norwegian subway station. Three different air samplers were used during a 72-h sampling campaign in February 2011. The results suggested that the airborne bacterial environment was stable between days and seasons, while the intraday variability was found to be substantial, although often following a consistent diurnal pattern. The bacterial levels ranged from not detected to 103 CFU m−3 and generally showed increased levels during the daytime compared to the nighttime levels, as well as during rush hours compared to non-rush hours. The airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly passengers) were demonstrated as major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. Our findings contribute to the development of realistic testing and evaluation schemes for BIODIM equipment by providing information that may be used to simulate operational bioaerosol backgrounds during controlled aerosol chamber-based challenge tests with biological threat agents. PMID:24162566

Histological findings in two renal transplants accomplishing operational tolerance criteria

PubMed Central

Azancot, M.A.; Cantarell, C.; Torres, I.B.; Serón, D.R.

2011-01-01

Operational tolerance is defined as stable renal function in transplants without immunosuppression for at least 1 year. We present histological assessments of two patients with operational tolerance. The first withdrew immunosuppression in 2005 and presents stable renal function (creatinine 1.5 mg/dL) without proteinuria. The biopsy showed mild chronic tubulointerstitial changes without inflammation. The second withdrew immunosuppression in 2009 and maintains stable renal function (creatinine 1.6 mg/dL) with mild proteinuria. Histology showed chronic humoural rejection and Class II anti-human leukocyte antigen antibodies were detected. These cases suggest that a renal biopsy may be useful to rule out subclinical pathology in patients with operational tolerance. PMID:25984157

Tomography and Purification of the Temporal-Mode Structure of Quantum Light

NASA Astrophysics Data System (ADS)

Ansari, Vahid; Donohue, John M.; Allgaier, Markus; Sansoni, Linda; Brecht, Benjamin; Roslund, Jonathan; Treps, Nicolas; Harder, Georg; Silberhorn, Christine

2018-05-01

High-dimensional quantum information processing promises capabilities beyond the current state of the art, but addressing individual information-carrying modes presents a significant experimental challenge. Here we demonstrate effective high-dimensional operations in the time-frequency domain of nonclassical light. We generate heralded photons with tailored temporal-mode structures through the pulse shaping of a broadband parametric down-conversion pump. We then implement a quantum pulse gate, enabled by dispersion-engineered sum-frequency generation, to project onto programmable temporal modes, reconstructing the quantum state in seven dimensions. We also manipulate the time-frequency structure by selectively removing temporal modes, explicitly demonstrating the effectiveness of engineered nonlinear processes for the mode-selective manipulation of quantum states.

A spatio-temporal analysis of suicide in El Salvador.

PubMed

Carcach, Carlos

2017-04-20

In 2012, international statistics showed El Salvador's suicide rate as 40th in the world and the highest in Latin America. Over the last 15 years, national statistics show the suicide death rate declining as opposed to an increasing rate of homicide. Though completed suicide is an important social and health issue, little is known about its prevalence, incidence, etiology and spatio-temporal behavior. The primary objective of this study was to examine completed suicide and homicide using the stream analogy to lethal violence within a spatio-temporal framework. A Bayesian model was applied to examine the spatio-temporal evolution of the tendency of completed suicide over homicide in El Salvador. Data on numbers of suicides and homicides at the municipal level were obtained from the Instituto de Medicina Legal (IML) and population counts, from the Dirección General de Estadística y Censos (DIGESTYC), for the period of 2002 to 2012. Data on migration were derived from the 2007 Population Census, and inequality data were obtained from a study by Damianović, Valenzuela and Vera. The data reveal a stable standardized rate of total lethal violence (completed suicide plus homicide) across municipalities over time; a decline in suicide; and a standardized suicide rate decreasing with income inequality but increasing with social isolation. Municipalities clustered in terms of both total lethal violence and suicide standardized rates. Spatial effects for suicide were stronger among municipalities located in the north-east and center-south sides of the country. New clusters of municipalities with large suicide standardized rates were detected in the north-west, south-west and center-south regions, all of which are part of time-stable clusters of homicide. Prevention efforts to reduce income inequality and mitigate the negative effects of weak relational systems should focus upon municipalities forming time-persistent clusters with a large rate of death by suicide. In

Entropy-stable summation-by-parts discretization of the Euler equations on general curved elements

NASA Astrophysics Data System (ADS)

Crean, Jared; Hicken, Jason E.; Del Rey Fernández, David C.; Zingg, David W.; Carpenter, Mark H.

2018-03-01

We present and analyze an entropy-stable semi-discretization of the Euler equations based on high-order summation-by-parts (SBP) operators. In particular, we consider general multidimensional SBP elements, building on and generalizing previous work with tensor-product discretizations. In the absence of dissipation, we prove that the semi-discrete scheme conserves entropy; significantly, this proof of nonlinear L2 stability does not rely on integral exactness. Furthermore, interior penalties can be incorporated into the discretization to ensure that the total (mathematical) entropy decreases monotonically, producing an entropy-stable scheme. SBP discretizations with curved elements remain accurate, conservative, and entropy stable provided the mapping Jacobian satisfies the discrete metric invariants; polynomial mappings at most one degree higher than the SBP operators automatically satisfy the metric invariants in two dimensions. In three-dimensions, we describe an elementwise optimization that leads to suitable Jacobians in the case of polynomial mappings. The properties of the semi-discrete scheme are verified and investigated using numerical experiments.

Spatial and Temporal Variations in Indoor Environmental Conditions, Human Occupancy, and Operational Characteristics in a New Hospital Building

PubMed Central

Ramos, Tiffanie; Dedesko, Sandra; Siegel, Jeffrey A.; Gilbert, Jack A.; Stephens, Brent

2015-01-01

The dynamics of indoor environmental conditions, human occupancy, and operational characteristics of buildings influence human comfort and indoor environmental quality, including the survival and progression of microbial communities. A suite of continuous, long-term environmental and operational parameters were measured in ten patient rooms and two nurse stations in a new hospital building in Chicago, IL to characterize the indoor environment in which microbial samples were taken for the Hospital Microbiome Project. Measurements included environmental conditions (indoor dry-bulb temperature, relative humidity, humidity ratio, and illuminance) in the patient rooms and nurse stations; differential pressure between the patient rooms and hallways; surrogate measures for human occupancy and activity in the patient rooms using both indoor air CO2 concentrations and infrared doorway beam-break counters; and outdoor air fractions in the heating, ventilating, and air-conditioning systems serving the sampled spaces. Measurements were made at 5-minute intervals over consecutive days for nearly one year, providing a total of ∼8×106 data points. Indoor temperature, illuminance, and human occupancy/activity were all weakly correlated between rooms, while relative humidity, humidity ratio, and outdoor air fractions showed strong temporal (seasonal) patterns and strong spatial correlations between rooms. Differential pressure measurements confirmed that all patient rooms were operated at neutral pressure. The patient rooms averaged about 100 combined entrances and exits per day, which suggests they were relatively lightly occupied compared to higher traffic environments (e.g., retail buildings) and more similar to lower traffic office environments. There were also clear differences in several environmental parameters before and after the hospital was occupied with patients and staff. Characterizing and understanding factors that influence these building dynamics is vital for

Spatial and temporal variations in indoor environmental conditions, human occupancy, and operational characteristics in a new hospital building

DOE PAGES

Ramos, Tiffanie; Dedesko, Sandra; Siegel, Jeffrey A.; ...

2015-03-02

The dynamics of indoor environmental conditions, human occupancy, and operational characteristics of buildings influence human comfort and indoor environmental quality, including the survival and progression of microbial communities. A suite of continuous, long-term environmental and operational parameters were measured in ten patient rooms and two nurse stations in a new hospital building in Chicago, IL to characterize the indoor environment in which microbial samples were taken for the Hospital Microbiome Project. Measurements included environmental conditions (indoor dry-bulb temperature, relative humidity, humidity ratio, and illuminance) in the patient rooms and nurse stations; differential pressure between the patient rooms and hallways; surrogatemore » measures for human occupancy and activity in the patient rooms using both indoor air CO₂ concentrations and infrared doorway beam-break counters; and outdoor air fractions in the heating, ventilating, and air-conditioning systems serving the sampled spaces. Measurements were made at 5-minute intervals over consecutive days for nearly one year, providing a total of ~8×10⁶ data points. Indoor temperature, illuminance, and human occupancy/activity were all weakly correlated between rooms, while relative humidity, humidity ratio, and outdoor air fractions showed strong temporal (seasonal) patterns and strong spatial correlations between rooms. Differential pressure measurements confirmed that all patient rooms were operated at neutral pressure. The patient rooms averaged about 100 combined entrances and exits per day, which suggests they were relatively lightly occupied compared to higher traffic environments (e.g., retail buildings) and more similar to lower traffic office environments. There were also clear differences in several environmental parameters before and after the hospital was occupied with patients and staff. Characterizing and understanding factors that influence these building dynamics is

Fuzzy branching temporal logic.

PubMed

Moon, Seong-ick; Lee, Kwang H; Lee, Doheon

2004-04-01

Intelligent systems require a systematic way to represent and handle temporal information containing uncertainty. In particular, a logical framework is needed that can represent uncertain temporal information and its relationships with logical formulae. Fuzzy linear temporal logic (FLTL), a generalization of propositional linear temporal logic (PLTL) with fuzzy temporal events and fuzzy temporal states defined on a linear time model, was previously proposed for this purpose. However, many systems are best represented by branching time models in which each state can have more than one possible future path. In this paper, fuzzy branching temporal logic (FBTL) is proposed to address this problem. FBTL adopts and generalizes concurrent tree logic (CTL*), which is a classical branching temporal logic. The temporal model of FBTL is capable of representing fuzzy temporal events and fuzzy temporal states, and the order relation among them is represented as a directed graph. The utility of FBTL is demonstrated using a fuzzy job shop scheduling problem as an example.

Explaining young adults' drinking behaviour within an augmented Theory of Planned Behaviour: temporal stability of drinker prototypes.

PubMed

van Lettow, Britt; de Vries, Hein; Burdorf, Alex; Conner, Mark; van Empelen, Pepijn

2015-05-01

Prototypes (i.e., social images) predict health-related behaviours and intentions within the context of the Theory of Planned Behaviour (TPB). This study tested the moderating role of temporal stability of drinker prototype perceptions on prototype-intentions and prototype-behaviour relationships, within an augmented TPB. The study examined abstainer, moderate drinker, heavy drinker, tipsy, and drunk prototypes. An online prospective study with 1-month follow-up was conducted among 410 young adults (18-25 years old, Mage = 21.0, SD = 2.14, 21.7% male). Assessed were prototype perceptions (favourability and similarity, T1, T2), stability of prototype perceptions, TPB variables (T1), intentions (T2), and drinking behaviour (T2). Intention analyses were corrected for baseline behaviour; drinking behaviour analyses were corrected for intentions and baseline behaviour. Hierarchical regressions showed that prototype stability moderated the relationships of drunk and abstainer prototype similarity with intentions. Similarity to the abstainer prototype explained intentions to drink sensibly more strongly among individuals with stable perceptions than among those with unstable perceptions. Conversely, intentions were explained stronger among individuals with stable perceptions of dissimilarity to the drunk prototype than among those with unstable perceptions. No moderation effects were found for stability of favourability or for relationships with behaviour. Stable prototype similarity perceptions were more predictive of intentions than unstable perceptions. These perceptions were most relevant in enhancing the explanation of young adults' intended drinking behaviour. Specifically, young adults' health intentions seem to be guided by the dissociation from the drunk prototype and association with the abstainer prototype. Statement of contribution What is already known on this subject? Prototypes have augmented the Theory of Planned Behaviour in explaining risk behaviour

Temporal changes in nitrogen adsorption properties of single-walled carbon nanotubes

USGS Publications Warehouse

Agnihotri, S.; Rostam-Abadi, M.; Rood, M.J.

2004-01-01

Temporal evolution of N2 adsorption (77 K) properties of as-produced and purified single-walled nanotubes (SWNTs) samples is described here. The N2 adsorption isotherms are used to characterize the samples' surface areas and porosities. The as-produced samples demonstrate a temporal increase in surface area and pore volumes for up to 16 months. The purified samples, however, reached their stable values of surface area and pore volumes within four to seven months. N2 adsorption capacity of the purified SWNTs also increased when the fresh samples were subjected to thermal pre-processing, with diminishing changes in adsorption capacity with increased age. These observations indicate that the freshly prepared SWNTs, both as-produced and purified, were in an unstable state with their porosity changing with increasing sample age and thermal treatments. It is hypothesized that SWNTs undergo slow but progressive changes in their surface chemistry which causes their N2 adsorption properties to change over several months. ?? 2004 Elsevier Ltd. All rights reserved.

Marine protected areas increase temporal stability of community structure, but not density or diversity, of tropical seagrass fish communities

PubMed Central

Jiddawi, Narriman S.; Eklöf, Johan S.

2017-01-01

Marine protected areas (MPAs) have been shown to increase long-term temporal stability of fish communities and enhance ecosystem resilience to anthropogenic disturbance. Yet, the potential ability of MPAs to buffer effects of environmental variability at shorter time scales remains widely unknown. In the tropics, the yearly monsoon cycle is a major natural force affecting marine organisms in tropical regions, and its timing and severity are predicted to change over the coming century, with potentially severe effects on marine organisms, ecosystems and ecosystem services. Here, we assessed the ability of MPAs to buffer effects of monsoon seasonality on seagrass-associated fish communities, using a field survey in two MPAs (no-take zones) and two unprotected (open-access) sites around Zanzibar (Tanzania). We assessed the temporal stability of fish density and community structure within and outside MPAs during three monsoon seasons in 2014–2015, and investigated several possible mechanisms that could regulate temporal stability. Our results show that MPAs did not affect fish density and diversity, but that juvenile fish densities were temporally more stable within MPAs. Second, fish community structure was more stable within MPAs for juvenile and adult fish, but not for subadult fish or the total fish community. Third, the observed effects may be due to a combination of direct and indirect (seagrass-mediated) effects of seasonality and, potentially, fluctuating fishing pressure outside MPAs. In summary, these MPAs may not have the ability to enhance fish density and diversity and to buffer effects of monsoon seasonality on the whole fish community. However, they may increase the temporal stability of certain groups, such as juvenile fish. Consequently, our results question whether MPAs play a general role in the maintenance of biodiversity and ecosystem functioning under changing environmental conditions in tropical seagrass fish communities. PMID:28854231

Stable isotope analysis of temporal variation in the diets of pre-fledged Laughing Gulls

USGS Publications Warehouse

Knoff, A.J.; Macko, S.A.; Erwin, R.M.; Brown, K.M.

2002-01-01

The *13C, *15N, and *34S stable isotopic values of feathers from pre-fledged Laughing Gulls (Larus atricilla) in coastal Virginia and Jamaica Bay, New York were used to examine dietary variation during the nestling period. The tip portions of the feathers were used to indicate diet during the initiation of primary feather growth, whereas the base portions indicated diet during the period immediately prior to fledging. The results indicate that diets of the nestlings in Virginia moved to a higher trophic level during the period prior to fledging, however the New York nestlings did not appear to undergo any appreciable dietary change during this period. Overall, nestlings from both colonies consumed proportionately more foods of marine origin than freshwater or terrestrial. Therefore, the results do not support those of earlier studies that suggested that partially developed salt glands in young gulls might restrict the diet to more terrestrial or freshwater prey in the early stages of nestling growth.

Spatio-temporal distribution and sources of Pb identified by stable isotopic ratios in sediments from the Yangtze River Estuary and adjacent areas.

PubMed

Chen, Bin; Liu, Jian; Hu, Limin; Liu, Ming; Wang, Liang; Zhang, Xilin; Fan, Dejiang

2017-02-15

To understand the spatio-temporal distribution and sources of Pb in the sediments of the Yangtze River Estuary and its adjacent areas, 25 surface sediments and 1 sediment core were collected from the study areas. The concentrations of Al and Pb of these sediments exhibit a decreasing trend from the nearshore towards the offshore, with higher concentrations in the coastal areas of the East China Sea (ECS) and southwest of Jeju Island. According to the stable isotopic ratios of Pb, in combination with the elemental ratios and clay mineral data, it is inferred that sedimentary Pb in the surface sediments of the coastal areas of the ECS may come primarily from the Yangtze River, while the Pb southwest of Jeju Island is probably derived from both the Yangtze and Yellow Rivers. The particulate Pb derived from the Yangtze River was possibly dispersed along two paths: the path southward along the coastline of the ECS and the path eastward associated with the Changjiang Diluted Water (CDW), which crosses the shelf of the ECS towards the area southeast of Jeju Island. Although the Yangtze River Basin witnessed rapid economic development during the period from the late 1970s to the middle 1990s, the influence of human activity on Pb concentration remained weak in the Yangtze River Estuary. Since the early 2000s, however, sedimentary Pb has been significantly increasing in the coastal mud areas of the ECS due to the increasing influence of human activity, such as the increase in atmospheric emission of anthropogenic Pb in China, construction of the Three Gorges Dam (TGD), and the construction of smaller dams in the upper reaches of the Yangtze River. Coal combustion and the smelting of non-ferrous metals are possible anthropogenic sources for the sedimentary Pb in the Yangtze River Estuary. Copyright © 2016. Published by Elsevier B.V.

Entropy Stable Wall Boundary Conditions for the Three-Dimensional Compressible Navier-Stokes Equations

NASA Technical Reports Server (NTRS)

Parsani, Matteo; Carpenter, Mark H.; Nielsen, Eric J.

2015-01-01

Non-linear entropy stability and a summation-by-parts framework are used to derive entropy stable wall boundary conditions for the three-dimensional compressible Navier-Stokes equations. A semi-discrete entropy estimate for the entire domain is achieved when the new boundary conditions are coupled with an entropy stable discrete interior operator. The data at the boundary are weakly imposed using a penalty flux approach and a simultaneous-approximation-term penalty technique. Although discontinuous spectral collocation operators on unstructured grids are used herein for the purpose of demonstrating their robustness and efficacy, the new boundary conditions are compatible with any diagonal norm summation-by-parts spatial operator, including finite element, finite difference, finite volume, discontinuous Galerkin, and flux reconstruction/correction procedure via reconstruction schemes. The proposed boundary treatment is tested for three-dimensional subsonic and supersonic flows. The numerical computations corroborate the non-linear stability (entropy stability) and accuracy of the boundary conditions.

Detection and Monitoring of Small-Scale Mining Operations in the Eastern Democratic Republic of the Congo (DRC) Using Multi-Temporal, Multi-Sensor Remote Sensing Data

NASA Astrophysics Data System (ADS)

Walther, Christian; Frei, Michaela

2017-04-01

Mining of so-called "conflict minerals" is often related with small-scale mining activities. The here discussed activities are located in forested areas in the eastern DRC, which are often remote, difficult to access and insecure for traditional geological field inspection. In order to accelerate their CTC (Certified Trading Chain)-certification process, remote sensing data are used for detection and monitoring of these small-scale mining operations. This requires a high image acquisition frequency due to mining site relocations and for compensation of year-round high cloud coverage, especially for optical data evaluation. Freely available medium resolution optical data of Sentinel-2 and Landsat-8 as well as SAR data of Sentinel-1 are used for detecting small mining targets with a minimum size of approximately 0.5 km2. The developed method enables a robust multi-temporal detection of mining sites, monitoring of mining site spatio-temporal relocations and environmental changes. Since qualitative and quantitative comparable results are generated, the followed change detection approach is objective and transparent and may push the certification process forward.

Towards the next generation of solid oxide fuel cells operating below 600 °c with chemically stable proton-conducting electrolytes.

PubMed

Fabbri, Emiliana; Bi, Lei; Pergolesi, Daniele; Traversa, Enrico

2012-01-10

The need for reducing the solid oxide fuel cell (SOFC) operating temperature below 600 °C is imposed by cost reduction, which is essential for widespread SOFC use, but might also disclose new applications. To this aim, high-temperature proton-conducting (HTPC) oxides have gained widespread interest as electrolyte materials alternative to oxygen-ion conductors. This Progress Report describes recent developments in electrolyte, anode, and cathode materials for protonic SOFCs, addressing the issue of chemical stability, processability, and good power performance below 600 °C. Different fabrication methods are reported for anode-supported SOFCs, obtained using state-of-the-art, chemically stable proton-conducting electrolyte films. Recent findings show significant improvements in the power density output of cells based on doped barium zirconate electrolytes, pointing out towards the feasibility of the next generation of protonic SOFCs, including a good potential for the development of miniaturized SOFCs as portable power supplies. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Environmentally stable all-PM all-fiber giant chirp oscillator.

PubMed

Erkintalo, Miro; Aguergaray, Claude; Runge, Antoine; Broderick, Neil G R

2012-09-24

We report on an environmentally stable giant chirp oscillator operating at 1030 nm. Thanks to the use of a nonlinear amplifying loop mirror as the mode-locker, we are able to extract pulse energies in excess of 10 nJ from a robust all-PM cavity with no free-space elements. Extensive numerical simulations reveal that the output oscillator energy and duration can simply be up-scaled through the lengthening of the cavity with suitably positioned single-mode fiber. Experimentally, using different cavity lengths we have achieved environmentally stable mode-locking at 10, 3.7 and 1.7 MHz with corresponding pulse energies of 2.3, 10 and 16 nJ. In all cases external grating-pair compression below 400 fs has been demonstrated.

Visual information for judging temporal range

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.; Mowafy, Lyn

1993-01-01

Work in our laboratory suggests that pilots can extract temporal range information (i.e., the time to pass a given waypoint) directly from out-the-window motion information. This extraction does not require the use of velocity or distance, but rather operates solely on a 2-D motion cue. In this paper, we present the mathematical derivation of this information, psychophysical evidence of human observers' sensitivity, and possible advantages and limitations of basing vehicle control on this parameter.

Stable Light-Emitting Diodes Using Phase-Pure Ruddlesden-Popper Layered Perovskites.

PubMed

Tsai, Hsinhan; Nie, Wanyi; Blancon, Jean-Christophe; Stoumpos, Constantinos C; Soe, Chan Myae Myae; Yoo, Jinkyoung; Crochet, Jared; Tretiak, Sergei; Even, Jacky; Sadhanala, Aditya; Azzellino, Giovanni; Brenes, Roberto; Ajayan, Pulickel M; Bulović, Vladimir; Stranks, Samuel D; Friend, Richard H; Kanatzidis, Mercouri G; Mohite, Aditya D

2018-02-01

State-of-the-art light-emitting diodes (LEDs) are made from high-purity alloys of III-V semiconductors, but high fabrication cost has limited their widespread use for large area solid-state lighting. Here, efficient and stable LEDs processed from solution with tunable color enabled by using phase-pure 2D Ruddlesden-Popper (RP) halide perovskites with a formula (CH 3 (CH 2 ) 3 NH 3 ) 2 (CH 3 NH 3 ) n -1 Pb n I 3 n +1 are reported. By using vertically oriented thin films that facilitate efficient charge injection and transport, efficient electroluminescence with a radiance of 35 W Sr -1 cm -2 at 744 nm with an ultralow turn-on voltage of 1 V is obtained. Finally, operational stability tests suggest that phase purity is strongly correlated to stability. Phase-pure 2D perovskites exhibit >14 h of stable operation at peak operating conditions with no droop at current densities of several Amperes cm -2 in comparison to mixtures of 2D/3D or 3D perovskites, which degrade within minutes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly stable cesium lead iodide perovskite quantum dot light-emitting diodes

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

Zou, Chen; Huang, Chun-Ying; Sanehira, Erin M.

Recently, all-inorganic perovskites such as CsPbBr3 and CsPbI3, have emerged as promising materials for light-emitting applications. While encouraging performance has been demonstrated, the stability issue of the red-emitting CsPbI3 is still a major concern due to its small tolerance factor. Here we report a highly stable CsPbI3 quantum dot LED with red emission fabricated using an improved purification approach. The device achieved decent external quantum efficiency (EQE) of 0.21 % at a bias of 6 V and outstanding operational stability, with a L70 lifetime (EL intensity decreases to 70% of starting value) of 16 h and 1.5 h under amore » constant driving voltage of 5 V and 6 V (maximum EQE operation) respectively. Furthermore, the device can work under a higher voltage of 7 V (maximum luminance operation) and retain 50% of its initial EL intensity after 500 s. These findings demonstrate the promise of CsPbI3 quantum dots for stable red LEDs, and suggest the feasibility for electrically pumped perovskite lasers with further device optimizations.« less

Highly stable cesium lead iodide perovskite quantum dot light-emitting diodes

DOE PAGES

Zou, Chen; Huang, Chun-Ying; Sanehira, Erin M.; ...

2017-09-11

Recently, all-inorganic perovskites such as CsPbBr3 and CsPbI3, have emerged as promising materials for light-emitting applications. While encouraging performance has been demonstrated, the stability issue of the red-emitting CsPbI3 is still a major concern due to its small tolerance factor. Here we report a highly stable CsPbI3 quantum dot LED with red emission fabricated using an improved purification approach. The device achieved decent external quantum efficiency (EQE) of 0.21 % at a bias of 6 V and outstanding operational stability, with a L70 lifetime (EL intensity decreases to 70% of starting value) of 16 h and 1.5 h under amore » constant driving voltage of 5 V and 6 V (maximum EQE operation) respectively. Furthermore, the device can work under a higher voltage of 7 V (maximum luminance operation) and retain 50% of its initial EL intensity after 500 s. These findings demonstrate the promise of CsPbI3 quantum dots for stable red LEDs, and suggest the feasibility for electrically pumped perovskite lasers with further device optimizations.« less

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

PubMed

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

2012-01-01

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

Analysing the Advantages of High Temporal Resolution Geostationary MSG SEVIRI Data Compared to Polar Operational Environmental Satellite Data for Land Surface Monitoring in Africa

NASA Technical Reports Server (NTRS)

Fensholt, R.; Anyamba, A.; Huber, S.; Proud, S. R.; Tucker, C. J.; Small, J.; Pak, E.; Rasmussen, M. O.; Sandholt, I.; Shisanya, C.

2011-01-01

Since 1972, satellite remote sensing of the environment has been dominated by polar-orbiting sensors providing useful data for monitoring the earth s natural resources. However their observation and monitoring capacity are inhibited by daily to monthly looks for any given ground surface which often is obscured by frequent and persistent cloud cover creating large gaps in time series measurements. The launch of the Meteosat Second Generation (MSG) satellite into geostationary orbit has opened new opportunities for land surface monitoring. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument on-board MSG with an imaging capability every 15 minutes which is substantially greater than any temporal resolution that can be obtained from existing polar operational environmental satellites (POES) systems currently in use for environmental monitoring. Different areas of the African continent were affected by droughts and floods in 2008 caused by periods of abnormally low and high rainfall, respectively. Based on the effectiveness of monitoring these events from Earth Observation (EO) data the current analyses show that the new generation of geostationary remote sensing data can provide higher temporal resolution cloud-free (less than 5 days) measurements of the environment as compared to existing POES systems. SEVIRI MSG 5-day continental scale composites will enable rapid assessment of environmental conditions and improved early warning of disasters for the African continent such as flooding or droughts. The high temporal resolution geostationary data will complement existing higher spatial resolution polar-orbiting satellite data for various dynamic environmental and natural resource applications of terrestrial ecosystems.

Small target detection using bilateral filter and temporal cross product in infrared images

NASA Astrophysics Data System (ADS)

Bae, Tae-Wuk

2011-09-01

We introduce a spatial and temporal target detection method using spatial bilateral filter (BF) and temporal cross product (TCP) of temporal pixels in infrared (IR) image sequences. At first, the TCP is presented to extract the characteristics of temporal pixels by using temporal profile in respective spatial coordinates of pixels. The TCP represents the cross product values by the gray level distance vector of a current temporal pixel and the adjacent temporal pixel, as well as the horizontal distance vector of the current temporal pixel and a temporal pixel corresponding to potential target center. The summation of TCP values of temporal pixels in spatial coordinates makes the temporal target image (TTI), which represents the temporal target information of temporal pixels in spatial coordinates. And then the proposed BF filter is used to extract the spatial target information. In order to predict background without targets, the proposed BF filter uses standard deviations obtained by an exponential mapping of the TCP value corresponding to the coordinate of a pixel processed spatially. The spatial target image (STI) is made by subtracting the predicted image from the original image. Thus, the spatial and temporal target image (STTI) is achieved by multiplying the STI and the TTI, and then targets finally are detected in STTI. In experimental result, the receiver operating characteristics (ROC) curves were computed experimentally to compare the objective performance. From the results, the proposed algorithm shows better discrimination of target and clutters and lower false alarm rates than the existing target detection methods.

Temporal Ventriloquism Reveals Intact Audiovisual Temporal Integration in Amblyopia.

PubMed

Richards, Michael D; Goltz, Herbert C; Wong, Agnes M F

2018-02-01

We have shown previously that amblyopia involves impaired detection of asynchrony between auditory and visual events. To distinguish whether this impairment represents a defect in temporal integration or nonintegrative multisensory processing (e.g., cross-modal matching), we used the temporal ventriloquism effect in which visual temporal order judgment (TOJ) is normally enhanced by a lagging auditory click. Participants with amblyopia (n = 9) and normally sighted controls (n = 9) performed a visual TOJ task. Pairs of clicks accompanied the two lights such that the first click preceded the first light, or second click lagged the second light by 100, 200, or 450 ms. Baseline audiovisual synchrony and visual-only conditions also were tested. Within both groups, just noticeable differences for the visual TOJ task were significantly reduced compared with baseline in the 100- and 200-ms click lag conditions. Within the amblyopia group, poorer stereo acuity and poorer visual acuity in the amblyopic eye were significantly associated with greater enhancement in visual TOJ performance in the 200-ms click lag condition. Audiovisual temporal integration is intact in amblyopia, as indicated by perceptual enhancement in the temporal ventriloquism effect. Furthermore, poorer stereo acuity and poorer visual acuity in the amblyopic eye are associated with a widened temporal binding window for the effect. These findings suggest that previously reported abnormalities in audiovisual multisensory processing may result from impaired cross-modal matching rather than a diminished capacity for temporal audiovisual integration.

Rational temporal predictions can underlie apparent failures to delay gratification.

PubMed

McGuire, Joseph T; Kable, Joseph W

2013-04-01

An important category of seemingly maladaptive decisions involves failure to postpone gratification. A person pursuing a desirable long-run outcome may abandon it in favor of a short-run alternative that has been available all along. Here we present a theoretical framework in which this seemingly irrational behavior emerges from stable preferences and veridical judgments. Our account recognizes that decision makers generally face uncertainty regarding the time at which future outcomes will materialize. When timing is uncertain, the value of persistence depends crucially on the nature of a decision maker's prior temporal beliefs. Certain forms of temporal beliefs imply that a delay's predicted remaining length increases as a function of time already waited. In this type of situation, the rational, utility-maximizing strategy is to persist for a limited amount of time and then give up. We show empirically that people's explicit predictions of remaining delay lengths indeed increase as a function of elapsed time in several relevant domains, implying that temporal judgments offer a rational basis for limiting persistence. We then develop our framework into a simple working model and show how it accounts for individual differences in a laboratory task (the well-known "marshmallow test"). We conclude that delay-of-gratification failure, generally viewed as a manifestation of limited self-control capacity, can instead arise as an adaptive response to the perceived statistics of one's environment.

Temporal Ventriloquism in a Purely Temporal Context

ERIC Educational Resources Information Center

Hartcher-O'Brien, Jessica; Alais, David

2011-01-01

This study examines how audiovisual signals are combined in time for a temporal analogue of the ventriloquist effect in a purely temporal context, that is, no spatial grounding of signals or other spatial facilitation. Observers were presented with two successive intervals, each defined by a 1250-ms tone, and indicated in which interval a brief…

Stable, low cost SAW microwave transmitter

NASA Astrophysics Data System (ADS)

Lau, K. F.; Yen, K. H.

1986-06-01

The design flexibility and application possibilities of surface acoustic wave (SAW) technology is discussed. When a highly stable, AM-modulated transmitter is required, a SAW resonator can provide an oscillator Q of up to 20,000 at 1 GHz. When FM modulation is required, the SAW delay line can provide a lower oscillator Q, which represents the optimum tradeoff between frequency stability and FM modulability. The capabilities of SAW oscillators are reviewed, and two example transmitters are presented. One transmitter operates at 1680 MHz and provides an AM-modulated signal. The second operates at the 400 to 406 MHz range and provides an FM-modulated output at one of six frequencies. SAW transmitters are suitable for applications where moderately high stability and low cost are key factors. With direct generation of signals at microwave frequencies and the flexibility of SAW oscillator design, a wide range of performance characteristics can be achieved.

Stable L-band multi-wavelength SOA fiber laser based on polarization rotation.

PubMed

Liu, Tonghui; Jia, Dongfang; Yang, Tianxin; Wang, Zhaoying; Liu, Ying

2017-04-01

We propose and experimentally demonstrate a stable multi-wavelength fiber ring laser operating in the L-band with wavelength spacing of 25 GHz. The mechanism is induced by a polarization rotation intensity equalizer consisting of a semiconductor optical amplifier and polarization devices. A Fabry-Perot filter is inserted into the cavity to serve as a multi-wavelength selection device. Stable L-band multi-wavelength lasing with 3 dB uniformity of 21.2 nm, and simultaneous oscillation of 101 lines with wavelength spacing of 25 GHz, is obtained.

Context effects and the temporal stability of stated preferences.

PubMed

Liebe, Ulf; Hundeshagen, Cordula; Beyer, Heiko; Cramon-Taubadel, Stephan von

2016-11-01

In stated preference studies it is assumed that individuals' answers reflect true preferences and are stable over time. We test these two assumptions of validity and reliability using as an example a choice experiment study on ethical consumption that measures preferences for a Peace Product jointly produced by Israeli and Palestinian producers as well as for organic products. In a web survey conducted in Germany, we investigate the validity assumption by manipulating the question context and presenting one group of respondents with questions on anti-Semitic and anti-Arabic attitudes before the choice tasks, and presenting another group with these questions after the choice tasks. In order to test the assumption of temporal stability, the same experimental set-up was repeated in a second survey based on a new sample ten months after the first. However, prior to the second survey an external event, a major violent dispute between Israelis and the Palestinians occurred. Overall, we find evidence for a context effect but not for temporal instability. In both surveys, the placement of the attitudinal questions before the choice tasks has a positive effect on the valuation of products from Israel, Palestinian products and the Peace Product (i.e. a directional context effect). The respondents seem to act according to an anti-discrimination norm. In line with this reasoning, we find an attention shift caused by the attitudinal questions. Organic products are valued much less positively if discriminatory attitudes are surveyed before the choice tasks. Furthermore, despite the violent dispute, stated preferences are very stable over time. This indicates high reliability of stated preference studies and encourages the use of study results by private and public decision makers. Copyright © 2016 Elsevier Inc. All rights reserved.

Efficient Red-Emitting Platinum Complex with Long Operational Stability.

PubMed

Fleetham, Tyler; Li, Guijie; Li, Jian

2015-08-05

A tetradentate cyclometalated Pt(II) complex, PtN3N-ptb, was developed as an emissive dopant for stable and efficient red phosphorescent OLEDs. Devices employing PtN3N-ptb in electrochemically stable device architectures achieved long operational lifetimes with estimated LT97, of over 600 h at luminances of 1000 cd/m(2). Such long operational lifetimes were achieved utilizing only literature reported host, transporting and blocking materials with known molecular structures. Additionally, a thorough study of the effects of various host and transport materials on the efficiency, turn on voltage, and stability of the devices was carried out. Ultimately, maximum forward viewing EQEs as high as 21.5% were achieved, demonstrating that Pt(II) complexes can act as stable and efficient dopants with operational lifetimes comparable or superior to those of the best literature-reported Ir(III) complexes.

Toward a simple, repeatable, non-destructive approach to measuring stable-isotope ratios of water within tree stems

NASA Astrophysics Data System (ADS)

Raulerson, S.; Volkmann, T.; Pangle, L. A.

2017-12-01

Traditional methodologies for measuring ratios of stable isotopes within the xylem water of trees involve destructive coring of the stem. A recent approach involves permanently installed probes within the stem, and an on-site assembly of pumps, switching valves, gas lines, and climate-controlled structure for field deployment of a laser spectrometer. The former method limits the possible temporal resolution of sampling, and sample size, while the latter may not be feasible for many research groups. We present results from initial laboratory efforts towards developing a non-destructive, temporally-resolved technique for measuring stable isotope ratios within the xylem flow of trees. Researchers have used direct liquid-vapor equilibration as a method to measure isotope ratios of the water in soil pores. Typically, this is done by placing soil samples in a fixed container, and allowing the liquid water within the soil to come into isotopic equilibrium with the headspace of the container. Water can also be removed via cryogenic distillation or azeotropic distillation, with the resulting liquid tested for isotope ratios. Alternatively, the isotope ratios of the water vapor can be directly measured using a laser-based water vapor isotope analyzer. Well-established fractionation factors and the isotope ratios in the vapor phase are then used to calculate the isotope ratios in the liquid phase. We propose a setup which would install a single, removable chamber onto a tree, where vapor samples could non-destructively and repeatedly be taken. These vapor samples will be injected into a laser-based isotope analyzer by a recirculating gas conveyance system. A major part of what is presented here is in the procedure of taking vapor samples at 100% relative humidity, appropriately diluting them with completely dry N2 calibration gas, and injecting them into the gas conveyance system without inducing fractionation in the process. This methodology will be helpful in making

Clinical studies of photodynamic therapy for malignant brain tumors: facial nerve palsy after temporal fossa photoillumination

NASA Astrophysics Data System (ADS)

Muller, Paul J.; Wilson, Brian C.; Lilge, Lothar D.; Varma, Abhay; Bogaards, Arjen; Fullagar, Tim; Fenstermaker, Robert; Selker, Robert; Abrams, Judith

2003-06-01

In two randomized prospective studies of brain tumor PDT more than 180 patients have been accrued. At the Toronto site we recognized two patients who developed a lower motor neuron (LMN) facial paralysis in the week following the PDT treatment. In both cases a temporal lobectomy was undertaken and the residual tumor cavity was photo-illuminated. The surface illuminated included the temporal fossa floor, thus potentially exposing the facial nerve to the effect of PDT. The number of frontal, temporal, parietal, and occipital tumors in this cohort was 39, 24, 12 and 4, respectively. Of the 24 temporal tumors 18 were randomized to Photofrin-PDT. Of these 18 a temporal lobectomy was carried out exposing the middle fossa floor as part of the tumor resection. In two of the 10 patients where the lobectomy was carried out and the fossa floor was exposed to light there occurred a postoperative facial palsy. Both patients recovered facial nerve function in 6 and 12 weeks, respectively. 46 J/cm2 were used in the former and 130 J/cm2 in the latter. We did not encounter a single post-operative LMN facial plasy in the 101 phase 2 patients treated with Photofrin-PDT. Among 688 supratentorial brain tumor operations in the last decade involving all pathologies and all locations no case of early post-operative LMN facial palsy was identified in the absence of PDT. One further patient who had a with post-PDT facial palsy was identified at the Denver site. Although it is possible that these patients had incidental Bell's palsy, we now recommend shielding the temporal fossa floor during PDT.

Detecting intraannual dietary variability in wild mountain gorillas by stable isotope analysis of feces

PubMed Central

Blumenthal, Scott A.; Chritz, Kendra L.; Rothman, Jessica M.; Cerling, Thure E.

2012-01-01

We use stable isotope ratios in feces of wild mountain gorillas (Gorilla beringei) to test the hypothesis that diet shifts within a single year, as measured by dry mass intake, can be recovered. Isotopic separation of staple foods indicates that intraannual changes in the isotopic composition of feces reflect shifts in diet. Fruits are isotopically distinct compared with other staple foods, and peaks in fecal δ13C values are interpreted as periods of increased fruit feeding. Bayesian mixing model results demonstrate that, although the timing of these diet shifts match observational data, the modeled increase in proportional fruit feeding does not capture the full shift. Variation in the isotopic and nutritional composition of gorilla foods is largely independent, highlighting the difficulty for estimating nutritional intake with stable isotopes. Our results demonstrate the potential value of fecal sampling for quantifying short-term, intraindividual dietary variability in primates and other animals with high temporal resolution even when the diet is composed of C3 plants. PMID:23236160

Gaussian temporal modulation for the behavior of multi-sinc Schell-model pulses in dispersive media

NASA Astrophysics Data System (ADS)

Liu, Xiayin; Zhao, Daomu; Tian, Kehan; Pan, Weiqing; Zhang, Kouwen

2018-06-01

A new class of pulse source with correlation being modeled by the convolution operation of two legitimate temporal correlation function is proposed. Particularly, analytical formulas for the Gaussian temporally modulated multi-sinc Schell-model (MSSM) pulses generated by such pulse source propagating in dispersive media are derived. It is demonstrated that the average intensity of MSSM pulses on propagation are reshaped from flat profile or a train to a distribution with a Gaussian temporal envelope by adjusting the initial correlation width of the Gaussian pulse. The effects of the Gaussian temporal modulation on the temporal degree of coherence of the MSSM pulse are also analyzed. The results presented here show the potential of coherence modulation for pulse shaping and pulsed laser material processing.

Neuromorphic infrared focal plane performs sensor fusion on-plane local-contrast-enhancement spatial and temporal filtering

NASA Astrophysics Data System (ADS)

Massie, Mark A.; Woolaway, James T., II; Curzan, Jon P.; McCarley, Paul L.

1993-08-01

An infrared focal plane has been simulated, designed and fabricated which mimics the form and function of the vertebrate retina. The `Neuromorphic' focal plane has the capability of performing pixel-based sensor fusion and real-time local contrast enhancement, much like the response of the human eye. The device makes use of an indium antimonide detector array with a 3 - 5 micrometers spectral response, and a switched capacitor resistive network to compute a real-time 2D spatial average. This device permits the summation of other sensor outputs to be combined on-chip with the infrared detections of the focal plane itself. The resulting real-time analog processed information thus represents the combined information of many sensors with the advantage that analog spatial and temporal signal processing is performed at the focal plane. A Gaussian subtraction method is used to produce the pixel output which when displayed produces an image with enhanced edges, representing spatial and temporal derivatives in the scene. The spatial and temporal responses of the device are tunable during operation, permitting the operator to `peak up' the response of the array to spatial and temporally varying signals. Such an array adapts to ambient illumination conditions without loss of detection performance. This paper reviews the Neuromorphic infrared focal plane from initial operational simulations to detailed design characteristics, and concludes with a presentation of preliminary operational data for the device as well as videotaped imagery.

Extracting 5m Shorelines From Multi-Temporal Images

NASA Astrophysics Data System (ADS)

Kapadia, A.; Jordahl, K. A.; Kington, J. D., IV

2016-12-01

Planet operates the largest Earth observing constellation of satellites, collecting imagery at an unprecedented temporal resolution. While daily cadence is expected in early 2017, Planet has already imaged the majority of landmass several dozen times over the past year. The current dataset provides enough value to build and test algorithms to automatically extract information. Here we demonstrate the extraction of shorelines across California using image stacks. The method implemented uses as input an uncalibrated RGB data product and limited NIR combined with the National Land Cover Database 2011 (NLCD2011) and Shuttle Radar Topography Mission (SRTM) to extract shorelines at 5 meter resolution. In the near future these methods along with daily cadence of imagery will allow for temporal monitoring of shorelines on a global scale.

An ultra-stable voltage source for precision Penning-trap experiments

NASA Astrophysics Data System (ADS)

Böhm, Ch.; Sturm, S.; Rischka, A.; Dörr, A.; Eliseev, S.; Goncharov, M.; Höcker, M.; Ketter, J.; Köhler, F.; Marschall, D.; Martin, J.; Obieglo, D.; Repp, J.; Roux, C.; Schüssler, R. X.; Steigleder, M.; Streubel, S.; Wagner, Th.; Westermann, J.; Wieder, V.; Zirpel, R.; Melcher, J.; Blaum, K.

2016-08-01

An ultra-stable and low-noise 25-channel voltage source providing 0 to -100 V has been developed. It will supply stable bias potentials for Penning-trap electrodes used in high-precision experiments. The voltage source generates all its supply voltages via a specially designed transformer. Each channel can be operated either in a precision mode or can be dynamically ramped. A reference module provides reference voltages for all the channels, each of which includes a low-noise amplifier to gain a factor of 10 in the output stage. A relative voltage stability of δV / V ≈ 2 ×10-8 has been demonstrated at -89 V within about 10 min.

Novel synthesis approach for stable sodium superoxide (NaO2) nanoparticles for LPG sensing application

NASA Astrophysics Data System (ADS)

Nemade, Kailash; Waghuley, Sandeep

2017-05-01

The synthesis of stable superoxide is still great challenge for the researchers working in the field of materials science. Through this letter, we report the novel and simple synthesis approach for the preparation of stable sodium superoxide (NaO2) nanoparticles. NaO2 nanoparticles were prepared by a spray pyrolysis technique, under oxygen rich environment for gas sensing application. The texture characterizations show that as-obtained NaO2 nanoparticles have high structural purity. Most importantly, NaO2 nanoparticles exhibits higher sensing response, shorter response time and recovery time, low operating temperature and good stability during sensing of liquefied petroleum gas (LPG). The main accomplishment of present work is that as-fabricated sensor has low operating temperature (423 K), which is below auto-ignition temperature of LPG. The gas sensing mechanism of NaO2 nanoparticles was discussed without the conventional oxygen bridging mechanism. Through this short communication, LPG sensing application of stable sodium superoxide nanoparticle is explored.

Highly stable, extremely high-temperature, nonvolatile memory based on resistance switching in polycrystalline Pt nanogaps

PubMed Central

Suga, Hiroshi; Suzuki, Hiroya; Shinomura, Yuma; Kashiwabara, Shota; Tsukagoshi, Kazuhito; Shimizu, Tetsuo; Naitoh, Yasuhisa

2016-01-01

Highly stable, nonvolatile, high-temperature memory based on resistance switching was realized using a polycrystalline platinum (Pt) nanogap. The operating temperature of the memory can be drastically increased by the presence of a sharp-edged Pt crystal facet in the nanogap. A short distance between the facet edges maintains the nanogap shape at high temperature, and the sharp shape of the nanogap densifies the electric field to maintain a stable current flow due to field migration. Even at 873 K, which is a significantly higher temperature than feasible for conventional semiconductor memory, the nonvolatility of the proposed memory allows stable ON and OFF currents, with fluctuations of less than or equal to 10%, to be maintained for longer than eight hours. An advantage of this nanogap scheme for high-temperature memory is its secure operation achieved through the assembly and disassembly of a Pt needle in a high electric field. PMID:27725705

An unusual case of complicated temporal lobe abscess following tympanomastoidectomy

PubMed Central

Yin, Tuanfang; Ren, Jihao; Lu, Yongde; Chen, Xing; Wang, Yaowen; Huang, Fengying

2013-01-01

We report a unusual case of complicated temporal lobe abscess following tympanomastoidectomy in a 26-year-old Chinese man here. The patient complained of binaural recurrent purulent discharge accompanied by hearing loss more than 10 years, then he received a right tympanomastoidectomy three months ago, but 3 weeks after surgery, he started to experience fierce headache and nausea and so on. The CT and MRI suggested the diagnosis of right temporal lobe abscess and then right temporal lobe abscess was excised. The patient was successfully treated with a right temporal lobe abscess resection and a radical right mastoidectomy. Although the cerebral abscess following radical tympanomastoidectomy are extremely rare, we should pay attention to it. we suggest the main reasons was still suffering from purulent discharge in the ear after the first tympanomastoidectomy, the granulation and cholesteatoma failed to completely remove during the first operation. and even resulted in substantial bone defect. It is well-known that good drainage is a key to reduce intra-cranial complications. PMID:23826430

Temporal Stability of the Ford Insomnia Response to Stress Test (FIRST).

PubMed

Jarrin, Denise C; Chen, Ivy Y; Ivers, Hans; Drake, Christopher L; Morin, Charles M

2016-10-15

The Ford Insomnia Response to Stress Test (FIRST) is a self-report tool that measures sleep reactivity (i.e., vulnerability to experience situational insomnia under stressful conditions). Sleep reactivity has been termed a "trait-like" vulnerability; however, evidence of its long-term stability is lacking. The main objective of the current psychometric study was to investigate the temporal stability of the FIRST over two 6-mo intervals in a population-based sample of adults with and without insomnia. The temporal stability of the FIRST was also compared with the temporal stability of other scales associated with insomnia (trait-anxiety, arousability). Participants included 1,122 adults (mean age = 49.9 y, standard deviation = 14.8; 38.8% male) presenting with an insomnia syndrome (n = 159), insomnia symptoms (n = 152), or good sleep (n = 811). Participants completed the FIRST, the State-Trait Anxiety Inventory (trait-anxiety), and the Arousal Predisposition Scale (arousability) on three different occasions: baseline and at 6- and 12-mo follow-up. Intraclass correlation coefficients (ICCs) were computed for all scales (baseline to 6 mo and 6 to 12 mo). The FIRST yielded strong temporal stability from baseline to 6 mo among those with insomnia syndrome (ICC = 0.81), symptoms (ICC = 0.78), and good sleep (ICC = 0.81). Similar results were observed for 6 to 12 mo among those with insomnia syndrome (ICC = 0.74), insomnia symptoms (ICC = 0.82), and good sleep (ICC = 0.84). The stability of the FIRST was not comparable with the stability of trait-anxiety, but was somewhat comparable with the stability of arousability. Overall, the FIRST is a temporally reliable stable scale over 6-mo intervals. Future research is needed to corroborate the stability and trait-like measures of sleep reactivity with physiological, behavioural and personality measures. © 2016 American Academy of Sleep Medicine

A spatial-temporal system for dynamic cadastral management.

PubMed

Nan, Liu; Renyi, Liu; Guangliang, Zhu; Jiong, Xie

2006-03-01

A practical spatio-temporal database (STDB) technique for dynamic urban land management is presented. One of the STDB models, the expanded model of Base State with Amendments (BSA), is selected as the basis for developing the dynamic cadastral management technique. Two approaches, the Section Fast Indexing (SFI) and the Storage Factors of Variable Granularity (SFVG), are used to improve the efficiency of the BSA model. Both spatial graphic data and attribute data, through a succinct engine, are stored in standard relational database management systems (RDBMS) for the actual implementation of the BSA model. The spatio-temporal database is divided into three interdependent sub-databases: present DB, history DB and the procedures-tracing DB. The efficiency of database operation is improved by the database connection in the bottom layer of the Microsoft SQL Server. The spatio-temporal system can be provided at a low-cost while satisfying the basic needs of urban land management in China. The approaches presented in this paper may also be of significance to countries where land patterns change frequently or to agencies where financial resources are limited.

Effects of spectral and temporal disruption on cortical encoding of gerbil vocalizations

PubMed Central

Ter-Mikaelian, Maria; Semple, Malcolm N.

2013-01-01

Animal communication sounds contain spectrotemporal fluctuations that provide powerful cues for detection and discrimination. Human perception of speech is influenced both by spectral and temporal acoustic features but is most critically dependent on envelope information. To investigate the neural coding principles underlying the perception of communication sounds, we explored the effect of disrupting the spectral or temporal content of five different gerbil call types on neural responses in the awake gerbil's primary auditory cortex (AI). The vocalizations were impoverished spectrally by reduction to 4 or 16 channels of band-passed noise. For this acoustic manipulation, an average firing rate of the neuron did not carry sufficient information to distinguish between call types. In contrast, the discharge patterns of individual AI neurons reliably categorized vocalizations composed of only four spectral bands with the appropriate natural token. The pooled responses of small populations of AI cells classified spectrally disrupted and natural calls with an accuracy that paralleled human performance on an analogous speech task. To assess whether discharge pattern was robust to temporal perturbations of an individual call, vocalizations were disrupted by time-reversing segments of variable duration. For this acoustic manipulation, cortical neurons were relatively insensitive to short reversal lengths. Consistent with human perception of speech, these results indicate that the stable representation of communication sounds in AI is more dependent on sensitivity to slow temporal envelopes than on spectral detail. PMID:23761696

Energy stable and high-order-accurate finite difference methods on staggered grids

NASA Astrophysics Data System (ADS)

O'Reilly, Ossian; Lundquist, Tomas; Dunham, Eric M.; Nordström, Jan

2017-10-01

For wave propagation over distances of many wavelengths, high-order finite difference methods on staggered grids are widely used due to their excellent dispersion properties. However, the enforcement of boundary conditions in a stable manner and treatment of interface problems with discontinuous coefficients usually pose many challenges. In this work, we construct a provably stable and high-order-accurate finite difference method on staggered grids that can be applied to a broad class of boundary and interface problems. The staggered grid difference operators are in summation-by-parts form and when combined with a weak enforcement of the boundary conditions, lead to an energy stable method on multiblock grids. The general applicability of the method is demonstrated by simulating an explosive acoustic source, generating waves reflecting against a free surface and material discontinuity.

Temporal response improvement for computed tomography fluoroscopy

NASA Astrophysics Data System (ADS)

Hsieh, Jiang

1997-10-01

Computed tomography fluoroscopy (CTF) has attracted significant attention recently. This is mainly due to the growing clinical application of CTF in interventional procedures, such as guided biopsy. Although many studies have been conducted for its clinical efficacy, little attention has been paid to the temporal response and the inherent limitations of the CTF system. For example, during a biopsy operation, when needle is inserted at a relatively high speed, the true needle position will not be correctly depicted in the CTF image due to the time delay. This could result in an overshoot or misplacement of the biopsy needle by the operator. In this paper, we first perform a detailed analysis of the temporal response of the CTF by deriving a set of equations to describe the average location of a moving object observed by the CTF system. The accuracy of the equations is verified by computer simulations and experiments. We show that the CT reconstruction process acts as a low pass filter to the motion function. As a result, there is an inherent time delay in the CTF process to the true biopsy needle motion and locations. Based on this study, we propose a generalized underscan weighting scheme which significantly improve the performance of CTF in terms of time lag and delay.

Bi-stable optical actuator

DOEpatents

Holdener, Fred R.; Boyd, Robert D.

2000-01-01

The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

An organic water-gated ambipolar transistor with a bulk heterojunction active layer for stable and tunable photodetection

NASA Astrophysics Data System (ADS)

Xu, Haihua; Zhu, Qingqing; Wu, Tongyuan; Chen, Wenwen; Zhou, Guodong; Li, Jun; Zhang, Huisheng; Zhao, Ni

2016-11-01

Organic water-gated transistors (OWGTs) have emerged as promising sensing architectures for biomedical applications and environmental monitoring due to their ability of in-situ detection of biological substances with high sensitivity and low operation voltage, as well as compatibility with various read-out circuits. Tremendous progress has been made in the development of p-type OWGTs. However, achieving stable n-type operation in OWGTs due to the presence of solvated oxygen in water is still challenging. Here, we report an ambipolar OWGT based on a bulk heterojunction active layer, which exhibits a stable hole and electron transport when exposed to aqueous environment. The device can be used as a photodetector both in the hole and electron accumulation regions to yield a maximum responsivity of 0.87 A W-1. More importantly, the device exhibited stable static and dynamic photodetection even when operated in the n-type mode. These findings bring possibilities for the device to be adopted for future biosensing platforms, which are fully compatible with low-cost and low-power organic complementary circuits.

One-Year stable perovskite solar cells by 2D/3D interface engineering

NASA Astrophysics Data System (ADS)

Grancini, G.; Roldán-Carmona, C.; Zimmermann, I.; Mosconi, E.; Lee, X.; Martineau, D.; Narbey, S.; Oswald, F.; de Angelis, F.; Graetzel, M.; Nazeeruddin, Mohammad Khaja

2017-06-01

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH2)4NH3)2PbI4/CH3NH3PbI3 perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm2 solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells.

One-Year stable perovskite solar cells by 2D/3D interface engineering

PubMed Central

Grancini, G.; Roldán-Carmona, C.; Zimmermann, I.; Mosconi, E.; Lee, X.; Martineau, D.; Narbey, S.; Oswald, F.; De Angelis, F.; Graetzel, M.; Nazeeruddin, Mohammad Khaja

2017-01-01

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH2)4NH3)2PbI4/CH3NH3PbI3 perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm2 solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells. PMID:28569749

One-Year stable perovskite solar cells by 2D/3D interface engineering.

PubMed

Grancini, G; Roldán-Carmona, C; Zimmermann, I; Mosconi, E; Lee, X; Martineau, D; Narbey, S; Oswald, F; De Angelis, F; Graetzel, M; Nazeeruddin, Mohammad Khaja

2017-06-01

Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH 2 ) 4 NH 3 ) 2 PbI 4 /CH 3 NH 3 PbI 3 perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm 2 solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells.

Stable Carbon Isotopes in Treerings; Revisiting the Paleocloud Proxy.

NASA Astrophysics Data System (ADS)

Gagen, M.; Zorita, E.; Dorado Liñán, I.; Loader, N.; McCarroll, D.; Robertson, I.; Young, G.

2017-12-01

The long term relationship between cloud cover and temperature is one of the most important climate feedbacks contributing to determining the value of climate sensitivity. Climate models still reveal a large spread in the simulation of changes in cloud cover under future warming scenarios and clarity might be aided by a picture of the past variability of cloudiness. Stable carbon isotope ratios from tree ring records have been successfully piloted as a palaeocloud proxy in geographical areas traditionally producing strong dendroclimatological reconstructions (high northern latitudes in the Northern Hemisphere) and with some notable successes elsewhere too. An expansion of tree-ring based palaeocloud reconstructions might help to estimate past variations of cloud cover in periods colder or warmer than the 20th century, providing a way to test model test this specific aspect. Calibration with measured instrumental sunshine and cloud data reveals stable carbon isotope ratios from tree rings as an indicator of incoming short wave solar radiation (SWR) in non-moisture stressed sites, but the statistical identification of the SWR signal is hampered by its interannual co-variability with air temperature during the growing season. Here we present a spatio-temporal statistical analysis of a multivariate stable carbon isotope tree ring data set over Europe to assess its usefulness to reconstruct past solar radiation changes. The interannual co-variability of the tree ring records stronger covariation with SWR than with air temperature. The resulting spatial patterns of interannual co-variability are strongly linked to atmospheric circulation in a physically consistent manner. However, the multidecadal variations in the proxy records show a less physically coherent picture. We explore whether atmospheric corrections applied to the proxy series are contributing to differences in the multi decadal signal and investigate whether multidecadal variations in soil moisture perturb

Entropy stable discontinuous interfaces coupling for the three-dimensional compressible Navier-Stokes equations

NASA Astrophysics Data System (ADS)

Parsani, Matteo; Carpenter, Mark H.; Nielsen, Eric J.

2015-06-01

Non-linear entropy stability and a summation-by-parts (SBP) framework are used to derive entropy stable interior interface coupling for the semi-discretized three-dimensional (3D) compressible Navier-Stokes equations. A complete semi-discrete entropy estimate for the interior domain is achieved combining a discontinuous entropy conservative operator of any order [1,2] with an entropy stable coupling condition for the inviscid terms, and a local discontinuous Galerkin (LDG) approach with an interior penalty (IP) procedure for the viscous terms. The viscous penalty contributions scale with the inverse of the Reynolds number (Re) so that for Re → ∞ their contributions vanish and only the entropy stable inviscid interface penalty term is recovered. This paper extends the interface couplings presented [1,2] and provides a simple and automatic way to compute the magnitude of the viscous IP term. The approach presented herein is compatible with any diagonal norm summation-by-parts (SBP) spatial operator, including finite element, finite volume, finite difference schemes and the class of high-order accurate methods which include the large family of discontinuous Galerkin discretizations and flux reconstruction schemes.

Determining Spatio-Temporal Cadastral Data Requirement for Infrastructure of Ladm for Turkey

NASA Astrophysics Data System (ADS)

Alkan, M.; Polat, Z. A.

2016-06-01

Nowadays, the nature of land title and cadastral (LTC) data in the Turkey is dynamic from a temporal perspective which depends on the LTC operations. Functional requirements with respect to the characteristics are investigated based upon interviews of professionals in public and private sectors. These are; Legal authorities, Land Registry and Cadastre offices, Highway departments, Foundations, Ministries of Budget, Transportation, Justice, Public Works and Settlement, Environment and Forestry, Agriculture and Rural Affairs, Culture and Internal Affairs, State Institute of Statistics (SIS), execution offices, tax offices, real estate offices, private sector, local governments and banks. On the other hand, spatio-temporal LTC data very important component for creating infrastructure of Land Administration Model (LADM). For this reason, spatio-temporal LTC data needs for LADM not only updated but also temporal. The investigations ended up with determine temporal analyses of LTC data, traditional LTC system and tracing temporal analyses in traditional LTC system. In the traditional system, the temporal analyses needed by all these users could not be performed in a rapid and reliable way. The reason for this is that the traditional LTC system is a manual archiving system. The aims and general contents of this paper: (1) define traditional LTC system of Turkey; (2) determining the need for spatio-temporal LTC data and analyses for core domain model for LADM. As a results of temporal and spatio-temporal analysis LTC data needs, new system design is important for the Turkish LADM model. Designing and realizing an efficient and functional Temporal Geographic Information Systems (TGIS) is inevitable for the Turkish LADM core infrastructure. Finally this paper outcome is creating infrastructure for design and develop LADM for Turkey.

Delay Discounting Rates Are Temporally Stable in an Equivalent Present Value Procedure Using Theoretical and Area under the Curve Analyses

ERIC Educational Resources Information Center

Harrison, Justin; McKay, Ryan

2012-01-01

Temporal discounting rates have become a popular dependent variable in social science research. While choice procedures are commonly employed to measure discounting rates, equivalent present value (EPV) procedures may be more sensitive to experimental manipulation. However, their use has been impeded by the absence of test-retest reliability data.…

Temporal Dynamics of the Human Vaginal Microbiota

PubMed Central

Gajer, Pawel; Brotman, Rebecca M.; Bai, Guoyun; Sakamoto, Joyce; Schütte, Ursel M.E.; Zhong, Xue; Koenig, Sara S.K.; Fu, Li; Ma, Zhanshan; Zhou, Xia; Abdo, Zaid; Forney, Larry J.; Ravel, Jacques

2012-01-01

Elucidating the factors that impinge on the stability of bacterial communities in the vagina may help in predicting the risk of diseases that affect women’s health. Here, we describe the temporal dynamics of the composition of vaginal bacterial communities in 32 reproductive age women over a 16-week period. The analysis revealed the dynamics of five major classes of bacterial communities and showed that some communities change markedly over short time periods, whereas others are relatively stable. Modeling community stability using new quantitative measures indicates that deviation from stability correlates with time in the menstrual cycle, bacterial community composition and sexual activity. The women studied are healthy, thus it appears that neither variation in community composition per se, nor higher levels of observed diversity (co-dominance) are necessarily indicative of dysbiosis, in which there is microbial imbalance accompanied by symptoms. PMID:22553250

The impact of rainfall on the temporal and spatial distribution of taxi passengers

PubMed Central

Zhang, Yong; Gao, Liangpeng; Geng, Nana; Li, Xuefeng

2017-01-01

This paper focuses on the impact of rainfall on the temporal and spatial distribution of taxi passengers. The main objective is to provide guidance for taxi scheduling on rainy days. To this end, we take the occupied and empty states of taxis as units of analysis. By matching a taxi's GPS data to its taximeter data, we can obtain the taxi's operational time and the taxi driver's income from every unit of analysis. The ratio of taxi operation time to taxi drivers' income is used to measure the quality of taxi passengers. The research results show that the spatio-temporal evolution of urban taxi service demand differs based on rainfall conditions and hours of operation. During non-rush hours, taxi demand in peripheral areas is significantly reduced under increasing precipitation conditions, whereas during rush hours, the demand for highly profitable taxi services steadily increases. Thus, as an intelligent response for taxi operations and dispatching, taxi services should guide cruising taxis to high-demand regions to increase their service time and ride opportunities. PMID:28873430

Spatio-temporal features for tracking and quadruped/biped discrimination

NASA Astrophysics Data System (ADS)

Rickman, Rick; Copsey, Keith; Bamber, David C.; Page, Scott F.

2012-05-01

Techniques such as SIFT and SURF facilitate efficient and robust image processing operations through the use of sparse and compact spatial feature descriptors and show much potential for defence and security applications. This paper considers the extension of such techniques to include information from the temporal domain, to improve utility in applications involving moving imagery within video data. In particular, the paper demonstrates how spatio-temporal descriptors can be used very effectively as the basis of a target tracking system and as target discriminators which can distinguish between bipeds and quadrupeds. Results using sequences of video imagery of walking humans and dogs are presented, and the relative merits of the approach are discussed.

Groundwater-fed irrigation impacts spatially distributed temporal scaling behavior of the natural system: a spatio-temporal framework for understanding water management impacts

NASA Astrophysics Data System (ADS)

Condon, Laura E.; Maxwell, Reed M.

2014-03-01

Regional scale water management analysis increasingly relies on integrated modeling tools. Much recent work has focused on groundwater-surface water interactions and feedbacks. However, to our knowledge, no study has explicitly considered impacts of management operations on the temporal dynamics of the natural system. Here, we simulate twenty years of hourly moisture dependent, groundwater-fed irrigation using a three-dimensional, fully integrated, hydrologic model (ParFlow-CLM). Results highlight interconnections between irrigation demand, groundwater oscillation frequency and latent heat flux variability not previously demonstrated. Additionally, the three-dimensional model used allows for novel consideration of spatial patterns in temporal dynamics. Latent heat flux and water table depth both display spatial organization in temporal scaling, an important finding given the spatial homogeneity and weak scaling observed in atmospheric forcings. Pumping and irrigation amplify high frequency (sub-annual) variability while attenuating low frequency (inter-annual) variability. Irrigation also intensifies scaling within irrigated areas, essentially increasing temporal memory in both the surface and the subsurface. These findings demonstrate management impacts that extend beyond traditional water balance considerations to the fundamental behavior of the system itself. This is an important step to better understanding groundwater’s role as a buffer for natural variability and the impact that water management has on this capacity.

Anatomical Study of Temporal Fat Compartments and its Clinical Application for Temporal Fat Grafting

PubMed Central

Huang, Ru-Lin; Xie, Yun; Wang, Wenjin; Herrler, Tanja; Zhou, Jia; Zhao, Peijuan; Pu, Lee LQ; Li, Qingfeng

2017-01-01

Abstract Background Low satisfaction rates and severe complications are two major limitations for temporal hollowing augmentation using autologous fat grafting. Despite fat compartments in temporal region have been reported, its clinical applied anatomy for fat grafting have not been the subject of studies that show its benefits objectively and statistically. Objectives To investigate temporal fat compartments and relative neurovascular structures in cadavers, developing a safe and effective fat grafting technique for temporal hollowing augmentation. Methods The study was conducted on 8 cadavers (16 temples). The tissue layers, fat compartments, ligaments, and neurovascular structures in the temporal region were analysed. The variables were the number and location of sentinel veins, perforator vessels of the middle temporal vein. Measurements were taken with a digital calliper. Results Two separate fat compartments, the lateral temporal-cheek fat compartment and lateral orbital fat compartment, were found in the subcutaneous layer, and two separate septum compartments, the upper and lower temporal compartment, were found in the loose areolar tissue layer. One sentinel vein and 1 to 6 perforator vessels were found to travel through the subcutaneous tissue layer, traverse the overlapping tissue layers in the lower temporal septum region, and finally join in the middle temporal vein. Conclusions The four fat compartments in the temporal region are ideal receipt sites for fat grafting. The medial border of the junction of the hairline and temporal line is a safe and effective cannula entry site for temporal fat grafting. The anterior half of the lower temporal compartment is a “zone of caution” for temporal fat grafting. PMID:28520850

Temporal variations in natural attenuation of chlorinated aliphatic hydrocarbons in eutrophic river sediments impacted by a contaminated groundwater plume.

PubMed

Hamonts, Kelly; Kuhn, Thomas; Vos, Johan; Maesen, Miranda; Kalka, Harald; Smidt, Hauke; Springael, Dirk; Meckenstock, Rainer U; Dejonghe, Winnie

2012-04-15

Chlorinated aliphatic hydrocarbons (CAHs) often discharge into rivers as contaminated groundwater baseflow. Biotransformation, sorption and dilution of CAHs in the impacted river sediments have been reported to reduce discharge, but the effect of temporal variations in environmental conditions on the occurrence and extent of those processes in river sediments is largely unknown. We monitored the reduction of CAH discharge into the Zenne River during a 21-month period. Despite a relatively stable influx of CAHs from the groundwater, the total reduction in CAH discharge from 120 to 20 cm depth in the river sediments, on average 74 ± 21%, showed moderate to large temporal variations, depending on the riverbed location. High organic carbon and anaerobic conditions in the river sediments allowed microbial reductive dechlorination of both chlorinated ethenes and chlorinated ethanes. δ(13)C values of the CAHs showed that this biotransformation was remarkably stable over time, despite fluctuating pore water temperatures. Daughter products of the CAHs, however, were not detected in stoichiometric amounts and suggested the co-occurrence of a physical process reducing the concentrations of CAHs in the riverbed. This process was the main process causing temporal variations in natural attenuation of the CAHs and was most likely dilution by surface water-mixing. However, higher spatial resolution monitoring of flow transients in the riverbed is required to prove dilution contributions due to dynamic surface water-groundwater flow exchanges. δ(13)C values and a site-specific isotope enrichment factor for reductive dechlorination of the main groundwater pollutant vinyl chloride (VC) allowed assessment of changes over time in the extent of both biotransformation and dilution of VC for different scenarios in which those processes either occurred consecutively or simultaneously between 120 and 20 cm depth in the riverbed. The extent of reductive dechlorination of VC ranged from 27

Brain Regions Underlying Word Finding Difficulties in Temporal Lobe Epilepsy

ERIC Educational Resources Information Center

Trebuchon-Da Fonseca, Agnes; Guedj, Eric; Alario, F-Xavier; Laguitton, Virginie; Mundler, Olivier; Chauvel, Patrick; Liegeois-Chauvel, Catherine

2009-01-01

Word finding difficulties are often reported by epileptic patients with seizures originating from the language dominant cerebral hemisphere, for example, in temporal lobe epilepsy. Evidence regarding the brain regions underlying this deficit comes from studies of peri-operative electro-cortical stimulation, as well as post-surgical performance.…

Reclaimed mineland curve number response to temporal distribution of rainfall

USGS Publications Warehouse

Warner, R.C.; Agouridis, C.T.; Vingralek, P.T.; Fogle, A.W.

2010-01-01

The curve number (CN) method is a common technique to estimate runoff volume, and it is widely used in coal mining operations such as those in the Appalachian region of Kentucky. However, very little CN data are available for watersheds disturbed by surface mining and then reclaimed using traditional techniques. Furthermore, as the CN method does not readily account for variations in infiltration rates due to varying rainfall distributions, the selection of a single CN value to encompass all temporal rainfall distributions could lead engineers to substantially under- or over-size water detention structures used in mining operations or other land uses such as development. Using rainfall and runoff data from a surface coal mine located in the Cumberland Plateau of eastern Kentucky, CNs were computed for conventionally reclaimed lands. The effects of temporal rainfall distributions on CNs was also examined by classifying storms as intense, steady, multi-interval intense, or multi-interval steady. Results indicate that CNs for such reclaimed lands ranged from 62 to 94 with a mean value of 85. Temporal rainfall distributions were also shown to significantly affect CN values with intense storms having significantly higher CNs than multi-interval storms. These results indicate that a period of recovery is present between rainfall bursts of a multi-interval storm that allows depressional storage and infiltration rates to rebound. ?? 2010 American Water Resources Association.

Surgical techniques in radiation induced temporal lobe necrosis in nasopharyngeal carcinoma patients.

PubMed

Alfotih, Gobran Taha Ahmed; Zheng, Mei Guang; Cai, Wang Qing; Xu, Xin Ke; Hu, Zhen; Li, Fang Cheng

2016-01-01

Radiation induced brain injury ranges from acute reversible edema to late, irreversible radiation necrosis. Radiation induced temporal lobe necrosis is associated with permanent neurological deficits and occasionally progresses to death. We present our experience with surgery on radiation induced temporal lobe necrosis (RTLN) in nasopharyngeal carcinoma (NPC) patients with special consideration of clinical presentation, surgical technique, and outcomes. This retrospective study includes 12 patients with RTLN treated by the senior author between January 2010 and December 2014. Patients initially sought medical treatment due to headache; other symptoms were hearing loss, visual deterioration, seizure, hemiparesis, vertigo, memory loss and agnosia. A temporal approach through a linear incision was performed for all cases. RTLN was found in one side in 7 patients, and bilaterally in 5. 4 patients underwent resection of necrotic tissue bilaterally and 8 patients on one side. No death occurred in this series of cases. There were no post-operative complications, except 1 patient who developed aseptic meningitis. All 12 patients were free from headache. No seizure occurred in patients with preoperative epilepsy. Other symptoms such as hemiparesis and vertigo improved in all patients. Memory loss, agnosia and hearing loss did not change post-operatively in all cases. The follow-up MR images demonstrated no recurrence of necrotic lesions in all 12 patients. Neurosurgical intervention through a temporal approach with linear incision is warranted in patients with radiation induced temporal lobe necrosis with significant symptoms and signs of increased intracranial pressure, minimum space occupying effect on imaging, or neurological deterioration despite conservative management. Copyright © 2016 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Quantitative and temporal proteome analysis of butyrate-treated colorectal cancer cells.

PubMed

Tan, Hwee Tong; Tan, Sandra; Lin, Qingsong; Lim, Teck Kwang; Hew, Choy Leong; Chung, Maxey C M

2008-06-01

Colorectal cancer is one of the most common cancers in developed countries, and its incidence is negatively associated with high dietary fiber intake. Butyrate, a short-chain fatty acid fermentation by-product of fiber induces cell maturation with the promotion of growth arrest, differentiation, and/or apoptosis of cancer cells. The stimulation of cell maturation by butyrate in colonic cancer cells follows a temporal progression from the early phase of growth arrest to the activation of apoptotic cascades. Previously we performed two-dimensional DIGE to identify differentially expressed proteins induced by 24-h butyrate treatment of HCT-116 colorectal cancer cells. Herein we used quantitative proteomics approaches using iTRAQ (isobaric tags for relative and absolute quantitation), a stable isotope labeling methodology that enables multiplexing of four samples, for a temporal study of HCT-116 cells treated with butyrate. In addition, cleavable ICAT, which selectively tags cysteine-containing proteins, was also used, and the results complemented those obtained from the iTRAQ strategy. Selected protein targets were validated by real time PCR and Western blotting. A model is proposed to illustrate our findings from this temporal analysis of the butyrate-responsive proteome that uncovered several integrated cellular processes and pathways involved in growth arrest, apoptosis, and metastasis. These signature clusters of butyrate-regulated pathways are potential targets for novel chemopreventive and therapeutic drugs for treatment of colorectal cancer.

Statistics of stable marriages

NASA Astrophysics Data System (ADS)

Dzierzawa, Michael; Oméro, Marie-José

2000-11-01

In the stable marriage problem N men and N women have to be matched by pairs under the constraint that the resulting matching is stable. We study the statistical properties of stable matchings in the large N limit using both numerical and analytical methods. Generalizations of the model including singles and unequal numbers of men and women are also investigated.

Inflammatory Pseudotumor of the Temporal Bone: A Case Series.

PubMed

Ortlip, Timothy E; Drake, Virginia E; Raghavan, Prashant; Papadimitriou, John C; Porter, Neil C; Eisenman, David J; Hertzano, Ronna

2017-08-01

Inflammatory pseudotumor of the temporal bone is a benign, idiopathic inflammatory process that is locally invasive and a cause of significant morbidity. This study reviews our experience with seven patients and is currently the largest series to date. Retrospective review from January 1, 2014 to January 1, 2016. Single tertiary medical center. There were five male and two female (n = 7) subjects with a diagnosis of temporal bone inflammatory pseudotumor. The mean age at presentation was 41 years old. The most common presenting symptoms were hearing loss (7/7) and headache (4/7). Four patients demonstrated an inflammatory aural polyp. Two patients experienced facial nerve paralysis. Seven patients underwent computed tomography and six underwent magnetic resonance imaging. Corticosteroids and antibiotics were the initial treatment of choice. Five patients also underwent surgery. As adjuvant therapy, two patients received Rituximab, one patient received radiation, and one received mycophenolate mofetil. Clinical courses were followed with focus on symptoms, disease recurrence, duration, and treatment. Mean follow-up was 17.8 months. The primary lesions demonstrated T2 hypo-intensity and enhancement as well as diffuse dural thickening on magnetic resonance imaging in five of six patients. Histopathology demonstrated chronic inflammation in the setting of hyalinized fibrosis (7/7). All the patients are currently symptomatically stable. Inflammatory pseudotumor of the temporal bone can cause devastating effects on neurological function and quality of life. Recognition of characteristic imaging and histopathology can expedite appropriate treatment. Patients may require chronic steroid therapy. Adjunctive therapy with radiation and immuno-modulation are currently being explored.

Stable carbonous catalyst particles and method for making and utilizing same

DOEpatents

Ganguli, Partha S.; Comolli, Alfred G.

2005-06-14

Stable carbonous catalyst particles composed of an inorganic catalytic metal/metal oxide powder and a carbonaceous binder material are formed having a basic inner substantially uniform-porous carbon coating of the catalytic powder, and may include an outer porous carbon coating layer. Suitable inorganic catalytic powders include zinc-chromite (ZnO/Cr.sub.2 03) and suitable carbonaceous liquid binders having molecular weight of 200-700 include partially polymerized furfuryl alcohol, which are mixed together, shaped and carbonized and partially oxidized at elevated temperature. Such stable carbonous catalyst particles such as 0.020-0.100 inch (0.51-2.54 mm) diameter extrudates, have total carbon content of 2-25 wt. % and improved crush strength of 1.0-5 1b/mn, 50-300 m.sup.2 /g surface area, and can be advantageously utilized in fixed bed or ebullated/fluidized bed reactor operations. This invention also includes method steps for making the stable carbonous catalyst particles having improved particle strength and catalytic activity, and processes for utilizing the active stable carbonous carbon-coated catalysts such as for syn-gas reactions in ebullated/fluidized bed reactors for producing alcohol products and Fischer-Tropsch synthesis liquid products.

Rational temporal predictions can underlie apparent failures to delay gratification

PubMed Central

McGuire, Joseph T.; Kable, Joseph W.

2013-01-01

An important category of seemingly maladaptive decisions involves failure to postpone gratification. A person pursuing a desirable long-run outcome may abandon it in favor of a short-run alternative that has been available all along. Here we present a theoretical framework in which this seemingly irrational behavior emerges from stable preferences and veridical judgments. Our account recognizes that decision makers generally face uncertainty regarding the time at which future outcomes will materialize. When timing is uncertain, the value of persistence depends crucially on the nature of a decision-maker’s prior temporal beliefs. Certain forms of temporal beliefs imply that a delay’s predicted remaining length increases as a function of time already waited. In this type of situation, the rational, utility-maximizing strategy is to persist for a limited amount of time and then give up. We show empirically that people’s explicit predictions of remaining delay lengths indeed increase as a function of elapsed time in several relevant domains, implying that temporal judgments offer a rational basis for limiting persistence. We then develop our framework into a simple working model and show how it accounts for individual differences in a laboratory task (the well-known “marshmallow test”). We conclude that delay-of-gratification failure, generally viewed as a manifestation of limited self-control capacity, can instead arise as an adaptive response to the perceived statistics of one’s environment. PMID:23458085

Stable "trait" variance of temperament as a predictor of the temporal course of depression and social phobia.

PubMed

Naragon-Gainey, Kristin; Gallagher, Matthew W; Brown, Timothy A

2013-08-01

A large body of research has found robust associations between dimensions of temperament (e.g., neuroticism, extraversion) and the mood and anxiety disorders. However, mood-state distortion (i.e., the tendency for current mood state to bias ratings of temperament) likely confounds these associations, rendering their interpretation and validity unclear. This issue is of particular relevance to clinical populations who experience elevated levels of general distress. The current study used the "trait-state-occasion" latent variable model (D. A. Cole, N. C. Martin, & J. H. Steiger, 2005) to separate the stable components of temperament from transient, situational influences such as current mood state. We examined the predictive power of the time-invariant components of temperament on the course of depression and social phobia in a large, treatment-seeking sample with mood and/or anxiety disorders (N = 826). Participants were assessed 3 times over the course of 1 year, using interview and self-report measures; most participants received treatment during this time. Results indicated that both neuroticism/behavioral inhibition (N/BI) and behavioral activation/positive affect (BA/P) consisted largely of stable, time-invariant variance (57% to 78% of total variance). Furthermore, the time-invariant components of N/BI and BA/P were uniquely and incrementally predictive of change in depression and social phobia, adjusting for initial symptom levels. These results suggest that the removal of state variance bolsters the effect of temperament on psychopathology among clinically distressed individuals. Implications for temperament-psychopathology models, psychopathology assessment, and the stability of traits are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Adaptive Gain-based Stable Power Smoothing of a DFIG

DOE PAGES

Muljadi, Eduard; Lee, Hyewon; Hwang, Min; ...

2017-11-01

In a power system that has a high wind penetration, the output power fluctuation of a large-scale wind turbine generator (WTG) caused by the varying wind speed increases the maximum frequency deviation, which is an important metric to assess the quality of electricity, because of the reduced system inertia. This paper proposes a stable power-smoothing scheme of a doubly-fed induction generator (DFIG) that can suppress the maximum frequency deviation, particularly for a power system with a high wind penetration. To do this, the proposed scheme employs an additional control loop relying on the system frequency deviation that operates in combinationmore » with the maximum power point tracking control loop. To improve the power-smoothing capability while guaranteeing the stable operation of a DFIG, the gain of the additional loop is modified with the rotor speed and frequency deviation. The gain is set to be high if the rotor speed and/or frequency deviation is large. Here, the simulation results based on the IEEE 14-bus system demonstrate that the proposed scheme significantly lessens the output power fluctuation of a WTG under various scenarios by modifying the gain with the rotor speed and frequency deviation, and thereby it can regulate the frequency deviation within a narrow range.« less

Adaptive Gain-based Stable Power Smoothing of a DFIG

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

Muljadi, Eduard; Lee, Hyewon; Hwang, Min

In a power system that has a high wind penetration, the output power fluctuation of a large-scale wind turbine generator (WTG) caused by the varying wind speed increases the maximum frequency deviation, which is an important metric to assess the quality of electricity, because of the reduced system inertia. This paper proposes a stable power-smoothing scheme of a doubly-fed induction generator (DFIG) that can suppress the maximum frequency deviation, particularly for a power system with a high wind penetration. To do this, the proposed scheme employs an additional control loop relying on the system frequency deviation that operates in combinationmore » with the maximum power point tracking control loop. To improve the power-smoothing capability while guaranteeing the stable operation of a DFIG, the gain of the additional loop is modified with the rotor speed and frequency deviation. The gain is set to be high if the rotor speed and/or frequency deviation is large. Here, the simulation results based on the IEEE 14-bus system demonstrate that the proposed scheme significantly lessens the output power fluctuation of a WTG under various scenarios by modifying the gain with the rotor speed and frequency deviation, and thereby it can regulate the frequency deviation within a narrow range.« less

Angle-stable and compressed angle-stable locking for tibiotalocalcaneal arthrodesis with retrograde intramedullary nails. Biomechanical evaluation.

PubMed

Mückley, Thomas; Hoffmeier, Konrad; Klos, Kajetan; Petrovitch, Alexander; von Oldenburg, Geert; Hofmann, Gunther O

2008-03-01

Retrograde intramedullary nailing is an established procedure for tibiotalocalcaneal arthrodesis. The goal of this study was to evaluate the effects of angle-stable locking or compressed angle-stable locking on the initial stability of the nails and on the behavior of the constructs under cyclic loading conditions. Tibiotalocalcaneal arthrodesis was performed in fifteen third-generation synthetic bones and twenty-four fresh-frozen cadaver legs with use of retrograde intramedullary nailing with three different locking modes: a Stryker nail with compressed angle-stable locking, a Stryker nail with angle-stable locking, and a statically locked Biomet nail. Analyses were performed of the initial stability of the specimens (range of motion) and the laxity of the constructs (neutral zone) in dorsiflexion/plantar flexion, varus/valgus, and external rotation/internal rotation. Cyclic testing up to 100,000 cycles was also performed. The range of motion and the neutral zone in dorsiflexion/plantar flexion at specific cycle increments were determined. In both bone models, the intramedullary nails with compressed angle-stable locking and those with angle-stable locking were significantly superior, in terms of a smaller range of motion and neutral zone, to the statically locked nails. The compressed angle-stable nails were superior to the angle-stable nails only in the synthetic bone model, in external/internal rotation. Cyclic testing showed the nails with angle-stable locking and those with compressed angle-stable locking to have greater stability in both models. In the synthetic bone model, compressed angle-stable locking was significantly better than angle-stable locking; in the cadaver bone model, there was no significant difference between these two locking modes. During cyclic testing, five statically locked nails in the cadaver bone model failed, whereas one nail with angle-stable locking and one with compressed angle-stable locking failed. Regardless of the bone model

Postoperative seizure freedom does not normalize altered connectivity in temporal lobe epilepsy.

PubMed

Maccotta, Luigi; Lopez, Mayra A; Adeyemo, Babatunde; Ances, Beau M; Day, Brian K; Eisenman, Lawrence N; Dowling, Joshua L; Leuthardt, Eric C; Schlaggar, Bradley L; Hogan, Robert Edward

2017-11-01

Specific changes in the functional connectivity of brain networks occur in patients with epilepsy. Yet whether such changes reflect a stable disease effect or one that is a function of active seizure burden remains unclear. Here, we longitudinally assessed the connectivity of canonical cognitive functional networks in patients with intractable temporal lobe epilepsy (TLE), both before and after patients underwent epilepsy surgery and achieved seizure freedom. Seventeen patients with intractable TLE who underwent epilepsy surgery with Engel class I outcome and 17 matched healthy controls took part in the study. The functional connectivity of a set of cognitive functional networks derived from typical cognitive tasks was assessed in patients, preoperatively and postoperatively, as well as in controls, using stringent methods of artifact reduction. Preoperatively, functional networks in TLE patients differed significantly from healthy controls, with differences that largely, but not exclusively, involved the default mode and temporal/auditory subnetworks. However, undergoing epilepsy surgery and achieving seizure freedom did not lead to significant changes in network connectivity, with postoperative functional network abnormalities closely mirroring the preoperative state. This result argues for a stable chronic effect of the disease on brain connectivity, with changes that are largely "burned in" by the time a patient with intractable TLE undergoes epilepsy surgery, which typically occurs years after the initial diagnosis. The result has potential implications for the treatment of intractable epilepsy, suggesting that delaying surgical intervention that may achieve seizure freedom may lead to functional network changes that are no longer reversible by the time of epilepsy surgery. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Reproductive responses to spatial and temporal prey availability in a coastal Arctic fox population.

PubMed

Eide, Nina E; Stien, Audun; Prestrud, Pål; Yoccoz, Nigel G; Fuglei, Eva

2012-05-01

1. Input of external subsidies in the Arctic may have substantial effects on predator populations that otherwise would have been limited by low local primary productivity. 2. We explore life-history traits, age-specific fecundity, litter sizes and survival, and the population dynamics of an Arctic fox (Vulpes lagopus) population to explore the influence of the spatial distribution and temporal availability of its main prey; including both resident and migrating (external) prey resources. 3. This study reveals that highly predictable cross-boundary subsidies from the marine food web, acting through seasonal access to seabirds, sustain larger local Arctic fox populations. Arctic fox dens located close to the coast in Svalbard were found to have higher occupancy rates, as expected from both high availability and high temporal and spatial predictability of prey resources (temporally stable external subsidies). Whereas the occupancy rate of inland dens varied between years in relation to the abundance of reindeer carcasses (temporally varying resident prey). 4. With regard to demography, juvenile Arctic foxes in Svalbard have lower survival rates and a high age of first reproduction compared with other populations. We suggest this may be caused by a lack of unoccupied dens and a saturated population. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

Temporal Proof Methodologies for Real-Time Systems,

DTIC Science & Technology

1990-09-01

real time systems that communicate either through shared variables or by message passing and real time issues such as time-outs, process priorities (interrupts) and process scheduling. The authors exhibit two styles for the specification of real - time systems . While the first approach uses bounded versions of temporal operators the second approach allows explicit references to time through a special clock variable. Corresponding to two styles of specification the authors present and compare two fundamentally different proof

Shear-Flow Instability Saturation by Stable Modes: Hydrodynamics and Gyrokinetics

NASA Astrophysics Data System (ADS)

Fraser, Adrian; Pueschel, M. J.; Terry, P. W.; Zweibel, E. G.

2017-10-01

We present simulations of shear-driven instabilities, focusing on the impact of nonlinearly excited, large-scale, linearly stable modes on the nonlinear cascade, momentum transport, and secondary instabilities. Stable modes, which have previously been shown to significantly affect instability saturation [Fraser et al. PoP 2017], are investigated in a collisionless, gyrokinetic, periodic zonal flow using the Gene code by projecting the results of nonlinear simulations onto a basis of linear eigenmodes that includes both stable and unstable modes. Benchmarking growth rates against previous gyrokinetic studies and an equivalent fluid system demonstrates comparable linear dynamics in the fluid and gyrokinetic systems. Cases of driven and decaying shear-flow turbulence are compared in Gene by using a Krook operator as an effective forcing. For comparison with existing hydrodynamic and MHD shear-flow instability studies, we present results for the shear layer obtained by similar means with the code Dedalus. Supported by U.S. DOE Grant No. DE-FG02-89ER53291, the NSF, and UW-Madison.

From EGEE Operations Portal towards EGI Operations Portal

NASA Astrophysics Data System (ADS)

Cordier, Hélène; L'Orphelin, Cyril; Reynaud, Sylvain; Lequeux, Olivier; Loikkanen, Sinikka; Veyre, Pierre

Grid operators in EGEE have been using a dedicated dashboard as their central operational tool, stable and scalable for the last 5 years despite continuous upgrade from specifications by users, monitoring tools or data providers. In EGEE-III, recent regionalisation of operations led the Operations Portal developers to conceive a standalone instance of this tool. We will see how the dashboard reorganization paved the way for the re-engineering of the portal itself. The outcome is an easily deployable package customized with relevant information sources and specific decentralized operational requirements. This package is composed of a generic and scalable data access mechanism, Lavoisier; a renowned php framework for configuration flexibility, Symfony and a MySQL database. VO life cycle and operational information, EGEE broadcast and Downtime notifications are next for the major reorganization until all other key features of the Operations Portal are migrated to the framework. Features specifications will be sketched at the same time to adapt to EGI requirements and to upgrade. Future work on feature regionalisation, on new advanced features or strategy planning will be tracked in EGI- Inspire through the Operations Tools Advisory Group, OTAG, where all users, customers and third parties of the Operations Portal are represented from January 2010.

Fin whales as bioindicators of multi-decadal change in carbon and oxygen stable isotope shifts in the North Atlantic.

PubMed

Borrell, A; Saiz, L; Víkingsson, G A; Gaufier, P; López Fernández, A; Aguilar, A

2018-07-01

Global changes, and particularly the massive release of CO 2 to the atmosphere and subsequent global warming, have altered the baselines of carbon and oxygen stable isotopic ratios. Temporal shifts in these baselines can be advantageously monitored through cetacean skin samples because these animals are highly mobile and therefore integrate in their tissues the heterogeneity of local environmental signals. In this study, we examine variation of δ 13 C and δ 18 O values in the skin of fin whales sampled over three decades in two different North Atlantic feeding grounds: west Iceland and northwest Spain. These locations are situated about 2700 km apart and thus represent a wide latitudinal range within the North Atlantic Ocean. The δ 13 C decrease in both areas is attributed to the burning of fossil fuels and increased deforestation worldwide, the so-called Suess effect. The dissimilarity in the magnitude of the shift between the two areas is coincidental with previous information on local shifts and lies within the ranges of variation observed. δ 18 O values experienced a minimal, yet significant change in fin whales from W Iceland (a decline of -0.44‰ between 1986 and 2013) but not in those from NW Spain. This is in concordance with a higher rise in temperatures in the former area than in the latter. The study validates the use of cetacean skin to monitor temporal and geographical shifts in stable isotopic values and alerts that, when applying this tool to ecological research, comparisons between sample sets should take into account temporal and latitudinal scales. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stable Adaptive Inertial Control of a Doubly-Fed Induction Generator

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

Kang, Moses; Muljadi, Eduard; Hur, Kyeon

2016-11-01

This paper proposes a stable adaptive inertial control scheme of a doubly-fed induction generator. The proposed power reference is defined in two sections: the deceleration period and the acceleration period. The power reference in the deceleration period consists of a constant and the reference for maximum power point tracking (MPPT) operation. The latter contributes to preventing a second frequency dip (SFD) in this period because its reduction rate is large at the early stage of an event but quickly decreases with time. To improve the frequency nadir (FN), the constant value is set to be proportional to the rotor speedmore » prior to an event. The reference ensures that the rotor speed converges to a stable operating region. To accelerate the rotor speed while causing a small SFD, when the rotor speed converges, the power reference is reduced by a small amount and maintained until it meets the MPPT reference. The results show that the scheme causes a small SFD while improving the FN and the rate of change of frequency in any wind conditions, even in a grid that has a high penetration of wind power.« less

Changes in stable isotope composition in Lake Michigan trout ...

EPA Pesticide Factsheets

Researchers have frequently sought to use environmental archives of sediment, peat and glacial ice to try and assess historical trends in atmospheric mercury (Hg) deposition to aquatic ecosystems. While this information is valuable in the context of identifying temporal source trends, these types of assessments cannot account for likely changes in bioavailability of Hg sources that are tied to the formation of methylmercury (MeHg) and accumulation in fish tissues. For this study we propose the use of long-term fish archives and Hg stable isotope determination as an improved means to relate temporal changes in fish Hg levels to varying Hg sources in the Great Lakes. For this study we acquired 180 archived fish composites from Lake Michigan over a 40-year time period (1975 to 2014) from the Great Lakes Fish Monitoring and Surveillance Program, which were analyzed for their total Hg content and Hg isotope abundances. The results reveal that Hg sources to Lake Michigan trout (Salvelinus namaycush) have encountered considerable changes as well as a large shift in the food web trophic position as a result of the introduction of several invasive species, especially the recent invasion of dreissenid mussels. Total Hg concentrations span a large range (1,600 to 150 ng g-1) and exhibit large variations from 1975 to 1985. Ä199Hg signatures similarly exhibit large variation (3.2 to 6.9‰) until 1985, followed by less variation through the end of the data record in 2014.

Greater temporal changes of sediment microbial community than its waterborne counterpart in Tengchong hot springs, Yunnan Province, China

PubMed Central

Wang, Shang; Dong, Hailiang; Hou, Weiguo; Jiang, Hongchen; Huang, Qiuyuan; Briggs, Brandon R.; Huang, Liuqin

2014-01-01

Temporal variation in geochemistry can cause changes in microbial community structure and diversity. Here we studied temporal changes of microbial communities in Tengchong hot springs of Yunnan Province, China in response to geochemical variations by using microbial and geochemical data collected in January, June and August of 2011. Greater temporal variations were observed in individual taxa than at the whole community structure level. Water and sediment communities exhibited different temporal variation patterns. Water communities were largely stable across three sampling times and dominated by similar microbial lineages: Hydrogenobaculum in moderate-temperature acidic springs, Sulfolobus in high-temperature acidic springs, and Hydrogenobacter in high-temperature circumneutral to alkaline springs. Sediment communities were more diverse and responsive to changing physicochemical conditions. Most of the sediment communities in January and June were similar to those in waters. However, the August sediment community was more diverse and contained more anaerobic heterotrophs than the January and June: Desulfurella and Acidicaldus in moderate-temperature acidic springs, Ignisphaera and Desulfurococcus in high-temperature acidic springs, the candidate division OP1 and Fervidobacterium in alkaline springs, and Thermus and GAL35 in neutral springs. Temporal variations in physicochemical parameters including temperature, pH, and dissolved organic carbon may have triggered the observed microbial community shifts. PMID:25524763

Temporal Discounting and Inter-Temporal Choice in Rhesus Monkeys

PubMed Central

Hwang, Jaewon; Kim, Soyoun; Lee, Daeyeol

2009-01-01

Humans and animals are more likely to take an action leading to an immediate reward than actions with delayed rewards of similar magnitudes. Although such devaluation of delayed rewards has been almost universally described by hyperbolic discount functions, the rate of this temporal discounting varies substantially among different animal species. This might be in part due to the differences in how the information about reward is presented to decision makers. In previous animal studies, reward delays or magnitudes were gradually adjusted across trials, so the animals learned the properties of future rewards from the rewards they waited for and consumed previously. In contrast, verbal cues have been used commonly in human studies. In the present study, rhesus monkeys were trained in a novel inter-temporal choice task in which the magnitude and delay of reward were indicated symbolically using visual cues and varied randomly across trials. We found that monkeys could extract the information about reward delays from visual symbols regardless of the number of symbols used to indicate the delay. The rate of temporal discounting observed in the present study was comparable to the previous estimates in other mammals, and the animal's choice behavior was largely consistent with hyperbolic discounting. Our results also suggest that the rate of temporal discounting might be influenced by contextual factors, such as the novelty of the task. The flexibility furnished by this new inter-temporal choice task might be useful for future neurobiological investigations on inter-temporal choice in non-human primates. PMID:19562091

Temporal networks

NASA Astrophysics Data System (ADS)

Holme, Petter; Saramäki, Jari

2012-10-01

A great variety of systems in nature, society and technology-from the web of sexual contacts to the Internet, from the nervous system to power grids-can be modeled as graphs of vertices coupled by edges. The network structure, describing how the graph is wired, helps us understand, predict and optimize the behavior of dynamical systems. In many cases, however, the edges are not continuously active. As an example, in networks of communication via e-mail, text messages, or phone calls, edges represent sequences of instantaneous or practically instantaneous contacts. In some cases, edges are active for non-negligible periods of time: e.g., the proximity patterns of inpatients at hospitals can be represented by a graph where an edge between two individuals is on throughout the time they are at the same ward. Like network topology, the temporal structure of edge activations can affect dynamics of systems interacting through the network, from disease contagion on the network of patients to information diffusion over an e-mail network. In this review, we present the emergent field of temporal networks, and discuss methods for analyzing topological and temporal structure and models for elucidating their relation to the behavior of dynamical systems. In the light of traditional network theory, one can see this framework as moving the information of when things happen from the dynamical system on the network, to the network itself. Since fundamental properties, such as the transitivity of edges, do not necessarily hold in temporal networks, many of these methods need to be quite different from those for static networks. The study of temporal networks is very interdisciplinary in nature. Reflecting this, even the object of study has many names-temporal graphs, evolving graphs, time-varying graphs, time-aggregated graphs, time-stamped graphs, dynamic networks, dynamic graphs, dynamical graphs, and so on. This review covers different fields where temporal graphs are considered

[Operative treatment of proximal humeral four-part fractures in elderly patients: comparison of two angular-stable implant systems].

PubMed

Kuhlmann, T; Hofmann, T; Seibert, O; Gundlach, G; Schmidt-Horlohé, K; Hoffmann, R

2012-04-01

Although being one of the most common fractures in elderly patients, there is still no standardised treatment protocol for four-part fractures of the proximal humerus. However, a wide variety of angular-stable implants is available. The present retrospective study compares the clinical and radiological outcome following operative treatment of four-part fractures of the proximal humerus with the Philos system (Philos, proximal humeral internal locking system, Synthes GmbH, Umkirch Germany) and the angular-stable Königsee plate system (Königsee Implantate GmbH, Allendorf, Germany) in patients older than 65 years. From July 2005 until December 2007 we identified 77 patients with a four-part fracture of the proximal humerus who were treated operatively with one of the two implant systems. Of the patients, 17 could not be located so that in total 60 patients (78 %) participated in this study. The mean age of the 30 patients (10 m, 20 f) in the Philos group was 69 years (65-92), whereas the mean age of the 30 patients (11 m, 19 f) in the Königsee group was 71 years (65-93). A comprehensive assessment was performed after a median of 17 months (12-24), including physical examination, radiographic examination and completion of the disabilities of the arm, shoulder and hand score (DASH) and the Constant score (CS) as patient-oriented, limb-specific questionnaires. Neither in the Philos nor in the Königsee group could excellent results be achieved. Using the CS 13 patients (43 %) of the Philos group achieved a good and 15 (50 %) a satisfactory result. Bad results were found in 2 patients (7 %). The mean CS was 61.53 points. In the Königsee group mean CS was 61.76 points. In detail, 14 patients (47 %) treated with the Königsee implant were rated as good and 15 (50 %) as satisfactory. Only 1 patient (3 %) was rated as poor. No significant statistical differences were found between the groups. Mean DASH score in the Philos group was 56.30 points and 55.37 points in the K�

Temporal mapping and analysis

NASA Technical Reports Server (NTRS)

O'Hara, Charles G. (Inventor); Shrestha, Bijay (Inventor); Vijayaraj, Veeraraghavan (Inventor); Mali, Preeti (Inventor)

2011-01-01

A compositing process for selecting spatial data collected over a period of time, creating temporal data cubes from the spatial data, and processing and/or analyzing the data using temporal mapping algebra functions. In some embodiments, the temporal data cube is creating a masked cube using the data cubes, and computing a composite from the masked cube by using temporal mapping algebra.

Face and content validation of a novel three-dimensional printed temporal bone for surgical skills development.

PubMed

Da Cruz, M J; Francis, H W

2015-07-01

To assess the face and content validity of a novel synthetic, three-dimensional printed temporal bone for surgical skills development and training. A synthetic temporal bone was printed using composite materials and three-dimensional printing technology. Surgical trainees were asked to complete three structured temporal bone dissection exercises. Attitudes and impressions were then assessed using a semi-structured questionnaire. Previous cadaver and real operating experiences were used as a reference. Trainees' experiences of the synthetic temporal bone were analysed in terms of four domains: anatomical realism, usefulness as a training tool, task-based usefulness and overall reactions. Responses across all domains indicated a high degree of acceptance, suggesting that the three-dimensional printed temporal bone was a useful tool in skills development. A sophisticated three-dimensional printed temporal bone that demonstrates face and content validity was developed. The efficiency in cost savings coupled with low associated biohazards make it likely that the printed temporal bone will be incorporated into traditional temporal bone skills development programmes in the near future.

Experimental temporal quantum steering

PubMed Central

Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

2016-01-01

Temporal steering is a form of temporal correlation between the initial and final state of a quantum system. It is a temporal analogue of the famous Einstein-Podolsky-Rosen (spatial) steering. We demonstrate, by measuring the photon polarization, that temporal steering allows two parties to verify if they have been interacting with the same particle, even if they have no information about what happened with the particle in between the measurements. This is the first experimental study of temporal steering. We also performed experimental tests, based on the violation of temporal steering inequalities, of the security of two quantum key distribution protocols against individual attacks. Thus, these results can lead to applications for secure quantum communications and quantum engineering. PMID:27901121

Stable high absorption metamaterial for wide-angle incidence of terahertz wave

NASA Astrophysics Data System (ADS)

Du, Qiujiao; Zeng, Zuoxun; Xiang, Dong; Lv, Tao; Zhang, Guangyong; Yang, Hongwu

2014-04-01

We propose a metamaterial based on metallic Jerusalem cross and cross-wire structures for realizing relatively stable high absorption with respect to the wide angle incidence of both polarized terahertz (THz) waves. Numerical simulations are carried out to verify the proposed absorber. For both transverse electric and transverse magnetic polarizations, absorptions around 0.93 THz reach nearly up to unity under normal incidence and maintain above 97% over a wide incidence angle range. The THz absorber can be easily micro-fabricated due to a thickness about 40 times smaller than operating wavelength. The proposed metamaterial is a promising candidate as absorbing element in THz thermal imager, due to its wide angle, stable high absorption and very thin thickness.

Surgical Management and Long-Term Seizure Outcome After Surgery for Temporal Lobe Epilepsy Associated with Cerebral Cavernous Malformations.

PubMed

Yang, Peng-Fan; Pei, Jia-Sheng; Jia, Yan-Zeng; Lin, Qiao; Xiao, Hui; Zhang, Ting-Ting; Zhong, Zhong-Hui

2018-02-01

Operative strategies for cerebral cavernous malformation (CCM)-associated temporal lobe epilepsy and timing of surgical intervention continue to be debated. This study aimed to establish an algorithm to evaluate the efficacy of surgical intervention strategies, to maximize positive surgical outcomes and minimize postsurgical neurologic deficits. 47 patients having undergone operation for CCM-associated temporal lobe epilepsy were retrospectively reviewed. They had received a diagnostic series for seizure localization, including long-term video electroencephalography (vEEG), high-resolution magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT). In patients with mesial temporal lobe CCMs, the involved structures (amygdala, hippocampus, or parahippocampal gyrus) were resected in addition to the lesions. Patients with neocortical epileptogenic CCM underwent extended lesionectomy guided by intraoperative electrocorticography; further performance of amygdalohippocampectomy depended on the extent of hippocampal epileptogenicity. The study cohort contained 28 patients with drug-resistant epilepsy (DRE), 12 with chronic epilepsy (CE), and 7 with sporadic seizure (SS). Normal temporal lobe metabolism was seen in 7/7 patients of the SS group. Hypometabolism was found in all patients with chronic disease except for those with posterior inferior and middle temporal gyrus cavernous malformations (CMs). Of the 31 patients with superficial neocortical CCM, 7 had normal PET without hippocampal sclerosis, 14 had ipsilateral temporal lobe hypometabolism without hippocampal sclerosis, and 10 had obvious hippocampal sclerosis and hypometabolism. Seizure freedom in DRE, CE, and SS was 82.1%, 75%, and 100%, respectively. A significant difference was found between lesion laterality and postoperative seizure control; the rate was lower in left-sided cases because of less aggressive resection. Our study demonstrates that the data from the

Taylor’s Law of Temporal Fluctuation Scaling in Stock Illiquidity

NASA Astrophysics Data System (ADS)

Cai, Qing; Xu, Hai-Chuan; Zhou, Wei-Xing

2016-08-01

Taylor’s law of temporal fluctuation scaling, variance ˜ a(mean)b, is ubiquitous in natural and social sciences. We report for the first time convincing evidence of a solid temporal fluctuation scaling law in stock illiquidity by investigating the mean-variance relationship of the high-frequency illiquidity of almost all stocks traded on the Shanghai Stock Exchange (SHSE) and the Shenzhen Stock Exchange (SZSE) during the period from 1999 to 2011. Taylor’s law holds for A-share markets (SZSE Main Board, SZSE Small & Mediate Enterprise Board, SZSE Second Board, and SHSE Main Board) and B-share markets (SZSE B-share and SHSE B-share). We find that the scaling exponent b is greater than 2 for the A-share markets and less than 2 for the B-share markets. We further unveil that Taylor’s law holds for stocks in 17 industry categories, in 28 industrial sectors and in 31 provinces and direct-controlled municipalities with the majority of scaling exponents b ∈ (2, 3). We also investigate the Δt-min illiquidity and find that the scaling exponent b(Δt) increases logarithmically for small Δt values and decreases fast to a stable level.

Coverage centralities for temporal networks*

NASA Astrophysics Data System (ADS)

Takaguchi, Taro; Yano, Yosuke; Yoshida, Yuichi

2016-02-01

Structure of real networked systems, such as social relationship, can be modeled as temporal networks in which each edge appears only at the prescribed time. Understanding the structure of temporal networks requires quantifying the importance of a temporal vertex, which is a pair of vertex index and time. In this paper, we define two centrality measures of a temporal vertex based on the fastest temporal paths which use the temporal vertex. The definition is free from parameters and robust against the change in time scale on which we focus. In addition, we can efficiently compute these centrality values for all temporal vertices. Using the two centrality measures, we reveal that distributions of these centrality values of real-world temporal networks are heterogeneous. For various datasets, we also demonstrate that a majority of the highly central temporal vertices are located within a narrow time window around a particular time. In other words, there is a bottleneck time at which most information sent in the temporal network passes through a small number of temporal vertices, which suggests an important role of these temporal vertices in spreading phenomena. Contribution to the Topical Issue "Temporal Network Theory and Applications", edited by Petter Holme.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjb/e2016-60498-7

Controlling for anthropogenically induced atmospheric variation in stable carbon isotope studies

USGS Publications Warehouse

Long, E.S.; Sweitzer, R.A.; Diefenbach, D.R.; Ben-David, M.

2005-01-01

Increased use of stable isotope analysis to examine food-web dynamics, migration, transfer of nutrients, and behavior will likely result in expansion of stable isotope studies investigating human-induced global changes. Recent elevation of atmospheric CO2 concentration, related primarily to fossil fuel combustion, has reduced atmospheric CO2 ??13C (13C/12C), and this change in isotopic baseline has, in turn, reduced plant and animal tissue ??13C of terrestrial and aquatic organisms. Such depletion in CO2 ??13C and its effects on tissue ??13C may introduce bias into ??13C investigations, and if this variation is not controlled, may confound interpretation of results obtained from tissue samples collected over a temporal span. To control for this source of variation, we used a high-precision record of atmospheric CO2 ??13C from ice cores and direct atmospheric measurements to model modern change in CO2 ??13C. From this model, we estimated a correction factor that controls for atmospheric change; this correction reduces bias associated with changes in atmospheric isotopic baseline and facilitates comparison of tissue ??13C collected over multiple years. To exemplify the importance of accounting for atmospheric CO2 ??13C depletion, we applied the correction to a dataset of collagen ??13C obtained from mountain lion (Puma concolor) bone samples collected in California between 1893 and 1995. Before correction, in three of four ecoregions collagen ??13C decreased significantly concurrent with depletion of atmospheric CO2 ??13C (n ??? 32, P ??? 0.01). Application of the correction to collagen ??13C data removed trends from regions demonstrating significant declines, and measurement error associated with the correction did not add substantial variation to adjusted estimates. Controlling for long-term atmospheric variation and correcting tissue samples for changes in isotopic baseline facilitate analysis of samples that span a large temporal range. ?? Springer-Verlag 2005.

Temporal Prediction Errors Affect Short-Term Memory Scanning Response Time.

PubMed

Limongi, Roberto; Silva, Angélica M

2016-11-01

The Sternberg short-term memory scanning task has been used to unveil cognitive operations involved in time perception. Participants produce time intervals during the task, and the researcher explores how task performance affects interval production - where time estimation error is the dependent variable of interest. The perspective of predictive behavior regards time estimation error as a temporal prediction error (PE), an independent variable that controls cognition, behavior, and learning. Based on this perspective, we investigated whether temporal PEs affect short-term memory scanning. Participants performed temporal predictions while they maintained information in memory. Model inference revealed that PEs affected memory scanning response time independently of the memory-set size effect. We discuss the results within the context of formal and mechanistic models of short-term memory scanning and predictive coding, a Bayes-based theory of brain function. We state the hypothesis that our finding could be associated with weak frontostriatal connections and weak striatal activity.

Effect of switching off unidirectional downflow systems of operating theaters during prolonged inactivity on the period before the operating theater can safely be used.

PubMed

Traversari, A A L; Bottenheft, C; van Heumen, S P M; Goedhart, C A; Vos, M C

2017-02-01

Switching off air handling systems in operating theaters during periods of prolonged inactivity (eg, nights, weekends) can produce a substantial reduction of energy expenditure. However, little evidence is available regarding the effect of switching off the air handling system during periods of prolonged inactivity on the air quality in operating theaters during operational periods. The aim of this study is to determine the amount of time needed after restarting the ventilation system to return to a stable situation, with air quality at least equal to the situation before switching off the system. Measurements were performed in 3 operating theaters, all of them equipped with a unidirectional downflow (UDF) system. Measurements (particle counts of emitted particles with a particle size ≥0.5 µm) were taken during the start-up of the ventilation system to determine when prespecified degrees of protection were achieved. Temperature readings were taken to determine when a stable temperature difference between the periphery and the protected area was reached, signifying achievement of a stable condition. After starting up the system, the protected area achieved the required degrees of protection within 20 minutes (95% upper confidence limit). A stable temperature difference was achieved within 23 minutes (95% upper confidence limit). Both findings lie well within the period of 25 minutes normally required for preparations before the start of surgical procedures. Switching off the ventilation system during prolonged inactivity (during the night and weekend) has no negative effect on the air quality in UDF operating theaters during normal operational hours. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Space Technology 5 Multi-point Observations of Field-aligned Currents: Temporal Variability of Meso-Scale Structures

NASA Technical Reports Server (NTRS)

Le, Guan; Wang, Yongli; Slavin, James A.; Strangeway, Robert J.

2007-01-01

Space Technology 5 (ST5) is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, sun-synchronous polar orbit from March 22 to June 21, 2006, for technology validations. In this paper, we present a study of the temporal variability of field-aligned currents using multi-point magnetic field measurements from ST5. The data demonstrate that meso-scale current structures are commonly embedded within large-scale field-aligned current sheets. The meso-scale current structures are very dynamic with highly variable current density and/or polarity in time scales of - 10 min. They exhibit large temporal variations during both quiet and disturbed times in such time scales. On the other hand, the data also shown that the time scales for the currents to be relatively stable are approx. 1 min for meso-scale currents and approx. 10 min for large scale current sheets. These temporal features are obviously associated with dynamic variations of their particle carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of meso-scale field-aligned currents are found to be consistent with those of auroral parallel electric field.

Space Technology 5 (ST-5) Multipoint Observations of Temporal and Spatial Variability of Field-Aligned Currents

NASA Technical Reports Server (NTRS)

Le, Guan

2010-01-01

Space Technology 5 (ST-5) is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, sun-synchronous polar orbit from March 22 to June 21, 2006, for technology validations. In this paper, we present a study of the temporal variability of field-aligned currents using multi-point magnetic field measurements from ST5. The data demonstrate that mesoscale current structures are commonly embedded within large-scale field-aligned current sheets. The meso-scale current structures are very dynamic with highly variable current density and/or polarity in time scales of about 10 min. They exhibit large temporal variations during both quiet and disturbed times in such time scales. On the other hand, the data also shown that the time scales for the currents to be relatively stable are about 1 min for meso-scale currents and about 10 min for large scale current sheets. These temporal features are obviously associated with dynamic variations of their particle carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of meso-scale field-aligned currents are found to be consistent with those of auroral parallel electric field.

Progressive contralateral hippocampal atrophy following surgery for medically refractory temporal lobe epilepsy.

PubMed

Elliott, Cameron A; Gross, Donald W; Wheatley, B Matt; Beaulieu, Christian; Sankar, Tejas

2016-09-01

Determine the extent and time course of volumetric changes in the contralateral hippocampus following surgery for medically refractory temporal lobe epilepsy (TLE). Serial T1-weighted MRI brain scans were obtained in 26 TLE patients pre- and post-temporal lobe epilepsy surgery as well as in 12 control subjects of similar age. Patients underwent either anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SAH). Blinded, manual hippocampal volumetry (head, body, and tail) was performed in two groups: 1) two scan group [ATL (n=6); SAH (n=10)], imaged pre-surgery and on average at 5.4 years post-surgery; and 2) longitudinal group [ATL (n=8); SAH (n=2)] imaged pre-surgery and on post-operative day 1, 2, 3, 6, 60, 120 and a delayed time point (average 2.4 years). In the two scan group, there was atrophy by 12% of the unresected contralateral hippocampus (p<0.001), with atrophy being most pronounced (27%) in the hippocampal body (p<0.001) with no significant differences seen for the hippocampal head or tail. In the longitudinal group, significant atrophy was also observed for the whole hippocampus and the body with atrophy seen as early as post-operative day #1 which progressed significantly over the first post-operative week (1.3%/day and 3.0%./day, respectively) before stabilizing over the long-term to a 13% reduction in total volume. There was no significant difference in atrophy compared by surgical approach (ATL vs. SAH; p=0.94) or side (p=0.31); however, atrophy was significantly more pronounced in patients with ongoing post-operative seizures (hippocampal body, p=0.019; whole hippocampus, p=0.048). There were no detectable post-operative neuropsychological deficits attributable to contralateral hippocampal atrophy. Significant contralateral hippocampal atrophy occurs following TLE surgery, which begins immediately and progresses over the first post-operative week. The observation that seizure free patients had significantly less atrophy of the

Unencapsulated Air-stable Organic Field Effect Transistor by All Solution Processes for Low Power Vapor Sensing

NASA Astrophysics Data System (ADS)

Feng, Linrun; Tang, Wei; Zhao, Jiaqing; Yang, Ruozhang; Hu, Wei; Li, Qiaofeng; Wang, Ruolin; Guo, Xiaojun

2016-02-01

With its excellent mechanical flexibility, low-cost and low-temperature processing, the solution processed organic field-effect transistor (OFET) is a promising platform technology for developing ubiquitous sensor applications in digital health, environment monitoring and Internet of Things. However, a contradiction between achieving low voltage operation and having stable performance severely hinder the technology to become commercially viable. This work shows that, by reducing the sub-gap density of states (DOS) at the channel for low operation voltage and using a proper low-k non-polar polymer dielectric layer, such an issue can be addressed. Stable electrical properties after either being placed for weeks or continuously prolonged bias stressing for hours in ambient air are achieved for all solution processed unencapsulated OFETs with the channel being exposed to the ambient air for analyte detection. The fabricated device presents a steep subthreshold swing less than 100 mV/decade, and an ON/OFF ratio of 106 at a voltage swing of 3 V. The low voltage and stable operation allows the sensor made of the OFET to be incorporated into a battery-powered electronic system for continuously reliable sensing of ammonia vapor in ambient air with very small power consumption of about 50 nW.

Unencapsulated Air-stable Organic Field Effect Transistor by All Solution Processes for Low Power Vapor Sensing

PubMed Central

Feng, Linrun; Tang, Wei; Zhao, Jiaqing; Yang, Ruozhang; Hu, Wei; Li, Qiaofeng; Wang, Ruolin; Guo, Xiaojun

2016-01-01

With its excellent mechanical flexibility, low-cost and low-temperature processing, the solution processed organic field-effect transistor (OFET) is a promising platform technology for developing ubiquitous sensor applications in digital health, environment monitoring and Internet of Things. However, a contradiction between achieving low voltage operation and having stable performance severely hinder the technology to become commercially viable. This work shows that, by reducing the sub-gap density of states (DOS) at the channel for low operation voltage and using a proper low-k non-polar polymer dielectric layer, such an issue can be addressed. Stable electrical properties after either being placed for weeks or continuously prolonged bias stressing for hours in ambient air are achieved for all solution processed unencapsulated OFETs with the channel being exposed to the ambient air for analyte detection. The fabricated device presents a steep subthreshold swing less than 100 mV/decade, and an ON/OFF ratio of 106 at a voltage swing of 3 V. The low voltage and stable operation allows the sensor made of the OFET to be incorporated into a battery-powered electronic system for continuously reliable sensing of ammonia vapor in ambient air with very small power consumption of about 50 nW. PMID:26861412

Stable and dynamic microtubules coordinately shape the myosin activation zone during cytokinetic furrow formation

PubMed Central

Foe, Victoria E.; von Dassow, George

2008-01-01

The cytokinetic furrow arises from spatial and temporal regulation of cortical contractility. To test the role microtubules play in furrow specification, we studied myosin II activation in echinoderm zygotes by assessing serine19-phosphorylated regulatory light chain (pRLC) localization after precisely timed drug treatments. Cortical pRLC was globally depressed before cytokinesis, then elevated only at the equator. We implicated cell cycle biochemistry (not microtubules) in pRLC depression, and differential microtubule stability in localizing the subsequent myosin activation. With no microtubules, pRLC accumulation occurred globally instead of equatorially, and loss of just dynamic microtubules increased equatorial pRLC recruitment. Nocodazole treatment revealed a population of stable astral microtubules that formed during anaphase; among these, those aimed toward the equator grew longer, and their tips coincided with cortical pRLC accumulation. Shrinking the mitotic apparatus with colchicine revealed pRLC suppression near dynamic microtubule arrays. We conclude that opposite effects of stable versus dynamic microtubules focuses myosin activation to the cell equator during cytokinesis. PMID:18955555

Managing temporal relations

NASA Technical Reports Server (NTRS)

Britt, Daniel L.; Geoffroy, Amy L.; Gohring, John R.

1990-01-01

Various temporal constraints on the execution of activities are described, and their representation in the scheduling system MAESTRO is discussed. Initial examples are presented using a sample activity described. Those examples are expanded to include a second activity, and the types of temporal constraints that can obtain between two activities are explored. Soft constraints, or preferences, in activity placement are discussed. Multiple performances of activities are considered, with respect to both hard and soft constraints. The primary methods used in MAESTRO to handle temporal constraints are described as are certain aspects of contingency handling with respect to temporal constraints. A discussion of the overall approach, with indications of future directions for this research, concludes the study.

Planning nonlinear access paths for temporal bone surgery.

PubMed

Fauser, Johannes; Sakas, Georgios; Mukhopadhyay, Anirban

2018-05-01

Interventions at the otobasis operate in the narrow region of the temporal bone where several highly sensitive organs define obstacles with minimal clearance for surgical instruments. Nonlinear trajectories for potential minimally invasive interventions can provide larger distances to risk structures and optimized orientations of surgical instruments, thus improving clinical outcomes when compared to existing linear approaches. In this paper, we present fast and accurate planning methods for such nonlinear access paths. We define a specific motion planning problem in [Formula: see text] with notable constraints in computation time and goal pose that reflect the requirements of temporal bone surgery. We then present [Formula: see text]-RRT-Connect: two suitable motion planners based on bidirectional Rapidly exploring Random Tree (RRT) to solve this problem efficiently. The benefits of [Formula: see text]-RRT-Connect are demonstrated on real CT data of patients. Their general performance is shown on a large set of realistic synthetic anatomies. We also show that these new algorithms outperform state-of-the-art methods based on circular arcs or Bézier-Splines when applied to this specific problem. With this work, we demonstrate that preoperative and intra-operative planning of nonlinear access paths is possible for minimally invasive surgeries at the otobasis.

Carbon and nitrogen biogeochemistry in the ocean: A study using stable isotope natural abundance

NASA Technical Reports Server (NTRS)

Rau, G. H.; Desmarais, David J.

1985-01-01

Determining the biogeochemical pathways traveled by carbon and nitrogen in the ocean is fundamental to the understanding of how the ocean participates in the cycling of these elements within the biosphere. Because biological production, metabolism, and respiration can significantly alter the natural abundance of C-13 and N-15, these abundances can provide important information about the nature of these biological processes and their variability in the marine environment. The research initially seeks to characterize the spatial and temporal patterns of stable isotope abundances in organic matter, and to relate these abundances to C and N biogeochemical processes within selected areas of the northeastern Pacific Ocean.

Improved Adjoint-Operator Learning For A Neural Network

NASA Technical Reports Server (NTRS)

Toomarian, Nikzad; Barhen, Jacob

1995-01-01

Improved method of adjoint-operator learning reduces amount of computation and associated computational memory needed to make electronic neural network learn temporally varying pattern (e.g., to recognize moving object in image) in real time. Method extension of method described in "Adjoint-Operator Learning for a Neural Network" (NPO-18352).

Wall-crossing between stable and co-stable ADHM data

NASA Astrophysics Data System (ADS)

Ohkawa, Ryo

2018-06-01

We prove formula between Nekrasov partition functions defined from stable and co-stable ADHM data for the plane following method by Nakajima and Yoshioka (Kyoto J Math 51(2):263-335, 2011) based on the theory of wall-crossing formula developed by Mochizuki (Donaldson type invariants for algebraic surfaces: transition of moduli stacks, Lecture notes in mathematics, vol 1972, Springer, Berlin, 2009). This formula is similar to conjectures by Ito et al. [J High Energy Phys 2013(5):045, 2013, (4.1), (4.2)] for A1 singularity.

Environmental DNA reflects spatial and temporal jellyfish distribution

PubMed Central

Fukuda, Miho; Katsuhara, Koki R.; Fujiwara, Ayaka; Hidaka, Shunsuke; Yamamoto, Satoshi; Takahashi, Kohji; Masuda, Reiji

2017-01-01

Recent development of environmental DNA (eDNA) analysis allows us to survey underwater macro-organisms easily and cost effectively; however, there have been no reports on eDNA detection or quantification for jellyfish. Here we present the first report on an eDNA analysis of marine jellyfish using Japanese sea nettle (Chrysaora pacifica) as a model species by combining a tank experiment with spatial and temporal distribution surveys. We performed a tank experiment monitoring eDNA concentrations over a range of time intervals after the introduction of jellyfish, and quantified the eDNA concentrations by quantitative real-time PCR. The eDNA concentrations peaked twice, at 1 and 8 h after the beginning of the experiment, and became stable within 48 h. The estimated release rates of the eDNA in jellyfish were higher than the rates previously reported in fishes. A spatial survey was conducted in June 2014 in Maizuru Bay, Kyoto, in which eDNA was collected from surface water and sea floor water samples at 47 sites while jellyfish near surface water were counted on board by eye. The distribution of eDNA in the bay corresponded with the distribution of jellyfish inferred by visual observation, and the eDNA concentration in the bay was ~13 times higher on the sea floor than on the surface. The temporal survey was conducted from March to November 2014, in which jellyfish were counted by eye every morning while eDNA was collected from surface and sea floor water at three sampling points along a pier once a month. The temporal fluctuation pattern of the eDNA concentrations and the numbers of observed individuals were well correlated. We conclude that an eDNA approach is applicable for jellyfish species in the ocean. PMID:28245277

Ultra-stable optical links for space and ground applications

NASA Astrophysics Data System (ADS)

Narbonneau, F.; Lours, M.; Daussy, C.; Lopez, O.; Clairon, A.; Santarelli, G.

2017-11-01

We have demonstrated the feasibility of a free-space ultra-stable optical link on a 3 meters test bench, operating at 100 MHz. With this type of link, it is possible to transfer a 100 MHz signal with a relative frequency stability of a few 10-14 at one second integration time, 10-16 at one day and a phase stability of a few picoseconds per day in presence of moderate mechanical vibrations and thermal fluctuations. The comparisons of modern clocks of distant (<100 km) Time and Frequency laboratories have a strong scientific interest. In this context we study a low noise frequency distribution via optical fibres. Some preliminary tests have been realized and the results are encouraging. We expect to transfer ultra stable oscillators with a relative frequency stability of a few 10-14 at one second integration time, 10-16 at one day.

[Prediction of round window visibility in cochlear implantation with temporal bone high resolution computed tomography].

PubMed

Sun, S P; Lu, W; Lei, Y B; Men, X M; Zuo, B; Ding, S G

2017-08-07

Objective: To discuss the prediction of round window(RW) visibility in cochlear implantation(CI) with temporal bone high resolution computed tomography(HRCT). Methods: From January 2013 to January 2017, 130 cases underwent both HRCT and CI in our hospital were analyzed. The distance from facial nerve to posterior canal wall(FWD), the angle between facial nerve and inner margin of round window(FRA), and the angle between facial nerve and tympanic anulus to inner margin of round window(FRAA) were detected at the level of round window on axial temporal bone HRCT. A line parallel to the posterior wall of ear canal was drawn from the anterior wall of facial nerve at the level of round window on axial temporal bone HRCT and its relationship with round window was detected (facial-round window line, FRL): type0-posterior to the round window, type1-between the round window, type2-anterior to the round window. Their(FWD, FRA, FRAA, FRL) relationships with intra-operative round window visibility were analyzed by SPSS 17.0 software. Results: FWD( F =18.76, P =0.00), FRA( F =34.57, P =0.00), FRAA ( F =14.24, P =0.00) could affect the intra-operative RW visibility significantly. RW could be exposed completely during CI when preoperative HRCT showing type0 FRL. RW might be partly exposed and not exposed when preoperative HRCT showing type1 and type2 FRL respectively. Conclusion: FWD, FRA, FRAA and FRL of temporal bone HRCT can predict intra-operative round window visibility effectively in CI surgery.

Applying AI tools to operational space environmental analysis

NASA Technical Reports Server (NTRS)

Krajnak, Mike; Jesse, Lisa; Mucks, John

1995-01-01

The U.S. Air Force and National Oceanic Atmospheric Agency (NOAA) space environmental operations centers are facing increasingly complex challenges meeting the needs of their growing user community. These centers provide current space environmental information and short term forecasts of geomagnetic activity. Recent advances in modeling and data access have provided sophisticated tools for making accurate and timely forecasts, but have introduced new problems associated with handling and analyzing large quantities of complex data. AI (Artificial Intelligence) techniques have been considered as potential solutions to some of these problems. Fielding AI systems has proven more difficult than expected, in part because of operational constraints. Using systems which have been demonstrated successfully in the operational environment will provide a basis for a useful data fusion and analysis capability. Our approach uses a general purpose AI system already in operational use within the military intelligence community, called the Temporal Analysis System (TAS). TAS is an operational suite of tools supporting data processing, data visualization, historical analysis, situation assessment and predictive analysis. TAS includes expert system tools to analyze incoming events for indications of particular situations and predicts future activity. The expert system operates on a knowledge base of temporal patterns encoded using a knowledge representation called Temporal Transition Models (TTM's) and an event database maintained by the other TAS tools. The system also includes a robust knowledge acquisition and maintenance tool for creating TTM's using a graphical specification language. The ability to manipulate TTM's in a graphical format gives non-computer specialists an intuitive way of accessing and editing the knowledge base. To support space environmental analyses, we used TAS's ability to define domain specific event analysis abstractions. The prototype system defines

A Temporal Map of Coaching.

PubMed

Theeboom, Tim; Van Vianen, Annelies E M; Beersma, Bianca

2017-01-01

Economic pressures on companies, technological developments, and less stable career paths pose potential threats to the well-being of employees (e.g., stress, burn-out) and require constant adaptation. In the light of these challenges, it is not surprising that employees often seek the support of a coach. The role of a coach is to foster change by facilitating a coachees' movement through a self-regulatory cycle with the ultimate aim of stimulating sustained well-being and functioning. While meta-analytic research indicates that coaching interventions can be effectively applied to assist employees in dealing with change, the current literature on coaching lacks solid theoretical frameworks that are needed to build a cumulative knowledge-base and to inspire evidence-based practice. In this conceptual analysis, we examine the coaching process through a temporal lens. By doing so, we provide an integrated theoretical framework: a temporal map of coaching. In this framework, we link seminal concepts in psychology to the coaching process, and describe which competencies of coachees are crucial in the different stages of change that coaching aims to bring about. During the preparatory contemplation stage, targeting coachees' awareness by enhancing their mindfulness and environmental receptiveness is important. During the contemplation stage, coachees' willingness and perceived ability to change are central competencies. We propose that coaches should therefore foster intrinsic goal orientation and self-efficacy during this stage. During the planning stage, coaches should focus on goal-setting and implementation intentions. Finally, during the maintenance/termination stage, stimulating coachees' reflection is especially important in order to help them to integrate their learning experiences. The framework delineated in this paper contributes to the understanding of coaching as a tool to assist employees in dealing with the challenges of an increasingly dynamic work

A Temporal Map of Coaching

PubMed Central

Theeboom, Tim; Van Vianen, Annelies E. M.; Beersma, Bianca

2017-01-01

Economic pressures on companies, technological developments, and less stable career paths pose potential threats to the well-being of employees (e.g., stress, burn-out) and require constant adaptation. In the light of these challenges, it is not surprising that employees often seek the support of a coach. The role of a coach is to foster change by facilitating a coachees’ movement through a self-regulatory cycle with the ultimate aim of stimulating sustained well-being and functioning. While meta-analytic research indicates that coaching interventions can be effectively applied to assist employees in dealing with change, the current literature on coaching lacks solid theoretical frameworks that are needed to build a cumulative knowledge-base and to inspire evidence-based practice. In this conceptual analysis, we examine the coaching process through a temporal lens. By doing so, we provide an integrated theoretical framework: a temporal map of coaching. In this framework, we link seminal concepts in psychology to the coaching process, and describe which competencies of coachees are crucial in the different stages of change that coaching aims to bring about. During the preparatory contemplation stage, targeting coachees’ awareness by enhancing their mindfulness and environmental receptiveness is important. During the contemplation stage, coachees’ willingness and perceived ability to change are central competencies. We propose that coaches should therefore foster intrinsic goal orientation and self-efficacy during this stage. During the planning stage, coaches should focus on goal-setting and implementation intentions. Finally, during the maintenance/termination stage, stimulating coachees’ reflection is especially important in order to help them to integrate their learning experiences. The framework delineated in this paper contributes to the understanding of coaching as a tool to assist employees in dealing with the challenges of an increasingly dynamic

Operational Impacts of Operating Reserve Demand Curves on Production Cost and Reliability

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

Krad, Ibrahim; Ibanez, Eduardo; Ela, Erik

The electric power industry landscape is continually evolving. As emerging technologies such as wind, solar, electric vehicles, and energy storage systems become more cost-effective and present in the system, traditional power system operating strategies will need to be reevaluated. The presence of wind and solar generation (commonly referred to as variable generation) may result in an increase in the variability and uncertainty of the net load profile. One mechanism to mitigate this is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increasedmore » variability and uncertainty occurring at finer temporal resolutions. A new operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this paper, and its implications on power system operations are analyzed.« less

Psychosis following temporal lobe surgery: a report of six cases.

PubMed Central

Mace, C J; Trimble, M R

1991-01-01

Six consecutive patients who had had temporal lobe surgery for epilepsy, and been referred for psychiatric assessment of psychotic symptoms, are reported. Their symptoms (a delusional depression, four schizophrenia-like illnesses, and a case of Capgras' syndrome) are discussed in relation to the possible role of their operations, all of which were on the right hemisphere. PMID:1895129

Second operation after the failure of previous resection for epilepsy.

PubMed

Awad, I A; Nayel, M H; Lüders, H

1991-04-01

We present our surgical experience with second operations in 15 patients with recurrent intractable partial seizures after resection for epilepsy. The interval from the first operation until the first recurrence of seizures ranged from 1 day to 7 months (mean, 62 days). The interval between the first and second operations ranged from 3 months to 12 years (mean, 38 months). Detailed video-electroencephalographic interictal and ictal recording was performed in all patients (invasive electrodes were used in 11 patients). Ictal onset was shown to be remote from the zone of previous resection in 3 of 15 cases (all 3 extratemporal and in the ipsilateral hemisphere). Recurrent seizures arose from the area of previous extratemporal resection in 2 of 15 patients, and from the area of previous temporal resection in 10 of 15 patients. Both cases of extratemporal recurrences and 3 of the 10 cases of temporal lobe recurrences in the area of previous resection were associated with residual unresected structural lesion. Of the 10 patients with local temporal recurrence, 6 had proven epileptogenicity in the residual mesial structures, and 4 had residual epileptogenicity in the unresected lateral temporal lobe. The patients have been monitored for 8 to 82 months (mean, 18 months) after the second operation: 7 patients (47%) have remained seizure-free and another 5 (33%) have achieved a reduction in seizure frequency of more than 90%. There was no mortality or significant morbidity in this series. We conclude that the extent and distribution of residual epileptogenicity after failed epilepsy surgery are highly variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal analysis of genetic structure to assess population dynamics of reintroduced swift foxes.

PubMed

Cullingham, Catherine I; Moehrenschlager, Axel

2013-12-01

Reintroductions are increasingly used to reestablish species, but a paucity of long-term postrelease monitoring has limited understanding of whether and when viable populations subsequently persist. We conducted temporal genetic analyses of reintroduced populations of swift foxes (Vulpes velox) in Canada (Alberta and Saskatchewan) and the United States (Montana). We used samples collected 4 years apart, 17 years from the initiation of the reintroduction, and 3 years after the conclusion of releases. To assess program success, we genotyped 304 hair samples, subsampled from the known range in 2000 and 2001, and 2005 and 2006, at 7 microsatellite loci. We compared diversity, effective population size, and genetic connectivity over time in each population. Diversity remained stable over time and there was evidence of increasing effective population size. We determined population structure in both periods after correcting for differences in sample sizes. The geographic distribution of these populations roughly corresponded with the original release locations, which suggests the release sites had residual effects on the population structure. However, given that both reintroduction sites had similar source populations, habitat fragmentation, due to cropland, may be associated with the population structure we found. Although our results indicate growing, stable populations, future connectivity analyses are warranted to ensure both populations are not subject to negative small-population effects. Our results demonstrate the importance of multiple sampling years to fully capture population dynamics of reintroduced populations. Análisis Temporal de la Estructura Genética para Evaluar la Dinámica Poblacional de Zorros (Vulpes velox) Reintroducidos. © 2013 Society for Conservation Biology.

Role of temporal processing stages by inferior temporal neurons in facial recognition.

PubMed

Sugase-Miyamoto, Yasuko; Matsumoto, Narihisa; Kawano, Kenji

2011-01-01

In this review, we focus on the role of temporal stages of encoded facial information in the visual system, which might enable the efficient determination of species, identity, and expression. Facial recognition is an important function of our brain and is known to be processed in the ventral visual pathway, where visual signals are processed through areas V1, V2, V4, and the inferior temporal (IT) cortex. In the IT cortex, neurons show selective responses to complex visual images such as faces, and at each stage along the pathway the stimulus selectivity of the neural responses becomes sharper, particularly in the later portion of the responses. In the IT cortex of the monkey, facial information is represented by different temporal stages of neural responses, as shown in our previous study: the initial transient response of face-responsive neurons represents information about global categories, i.e., human vs. monkey vs. simple shapes, whilst the later portion of these responses represents information about detailed facial categories, i.e., expression and/or identity. This suggests that the temporal stages of the neuronal firing pattern play an important role in the coding of visual stimuli, including faces. This type of coding may be a plausible mechanism underlying the temporal dynamics of recognition, including the process of detection/categorization followed by the identification of objects. Recent single-unit studies in monkeys have also provided evidence consistent with the important role of the temporal stages of encoded facial information. For example, view-invariant facial identity information is represented in the response at a later period within a region of face-selective neurons. Consistent with these findings, temporally modulated neural activity has also been observed in human studies. These results suggest a close correlation between the temporal processing stages of facial information by IT neurons and the temporal dynamics of face recognition.

Role of Temporal Processing Stages by Inferior Temporal Neurons in Facial Recognition

PubMed Central

Sugase-Miyamoto, Yasuko; Matsumoto, Narihisa; Kawano, Kenji

2011-01-01

In this review, we focus on the role of temporal stages of encoded facial information in the visual system, which might enable the efficient determination of species, identity, and expression. Facial recognition is an important function of our brain and is known to be processed in the ventral visual pathway, where visual signals are processed through areas V1, V2, V4, and the inferior temporal (IT) cortex. In the IT cortex, neurons show selective responses to complex visual images such as faces, and at each stage along the pathway the stimulus selectivity of the neural responses becomes sharper, particularly in the later portion of the responses. In the IT cortex of the monkey, facial information is represented by different temporal stages of neural responses, as shown in our previous study: the initial transient response of face-responsive neurons represents information about global categories, i.e., human vs. monkey vs. simple shapes, whilst the later portion of these responses represents information about detailed facial categories, i.e., expression and/or identity. This suggests that the temporal stages of the neuronal firing pattern play an important role in the coding of visual stimuli, including faces. This type of coding may be a plausible mechanism underlying the temporal dynamics of recognition, including the process of detection/categorization followed by the identification of objects. Recent single-unit studies in monkeys have also provided evidence consistent with the important role of the temporal stages of encoded facial information. For example, view-invariant facial identity information is represented in the response at a later period within a region of face-selective neurons. Consistent with these findings, temporally modulated neural activity has also been observed in human studies. These results suggest a close correlation between the temporal processing stages of facial information by IT neurons and the temporal dynamics of face recognition

Spatial and temporal dependence on sea ice algae in the Chukchi Sea, Arctic Ocean, inferred from bivalve stable isotopic composition

NASA Astrophysics Data System (ADS)

Nguyen, H. M.; Black, B.; Dunton, K. H.; von Biela, V. R.

2017-12-01

The Chukchi Sea is one of the most productive Arctic seas in the world. Around 10% of its net primary production originates from sea ice algae, much of which falls ungrazed to a relatively shallow (40-50m) shelf. The chlorophyll a derived from sinking ice algae is thought to supports a robust macrobenthic faunal community, dominated by bivalves, which in turn supports higher trophic organisms such as Pacific walrus (Odibenus rosmarus divergens), and bearded seal (Erignathus barbatus). However, recent reductions in ice extent and thickness could shift primary production from under-ice to open-water environment, thus reducing ice algal production and delivery to benthic biota. We used stable isotope analyses on benthic bivalve samples, collected in summer between 2002 and 2015, to identify contributions of ice algal production to benthic organisms and track their spatial and temporal variations. Ice algae contributions were indicated by δ13C values in bivalves, as ice algae are isotopically heavy compared to phytoplankton and would be reflected in consumers. This 14-yr period was marked by an 8%, decrease in Arctic ice extent, which was especially pronounced and spatially variable in the Chukchi Sea. We examined variability in the δ13C values in the common bivalves Astarte spp., Ennucula tenuis and Macoma spp. over space and time using one-way ANOVAs with Bonferroni correction to consider the potential for variation in ice algae contributions. All bivalve δ13C values were within a range (-21.84‰ to -17.62‰) that suggests some ice algal contribution. Among stations, E. tenuis and Astarte spp. did not significantly differ in their individual δ13C values. In contrast, Macoma spp. had significantly enriched δ13C values at one station south of Point Hope (δ13C = -17.75‰, F5,8 = 1.211, P < 0.05) in 2015. There were no significant (P > 0.05) differences in δ13C values from year to year for samples pooled across stations within a taxon. As the only taxon

Surface Subsidence Analysis by Multi-Temporal InSAR and GRACE: A Case Study in Beijing.

PubMed

Guo, Jiming; Zhou, Lv; Yao, Chaolong; Hu, Jiyuan

2016-09-14

The aim of this study was to investigate the relationship between surface subsidence and groundwater changes. To investigate this relationship, we first analyzed surface subsidence. This paper presents the results of a case study of surface subsidence in Beijing from 1 August 2007 to 29 September 2010. The Multi-temporal Interferometric Synthetic Aperture Radar (multi-temporal InSAR) technique, which can simultaneously detect point-like stable reflectors (PSs) and distributed scatterers (DSs), was used to retrieve the subsidence magnitude and distribution in Beijing using 18 ENVISAT ASAR images. The multi-temporal InSAR-derived subsidence was verified by leveling at an accuracy better than 5 mm/year. Based on the verified multi-temporal InSAR results, a prominent uneven subsidence was identified in Beijing. Specifically, most of the subsidence velocities in the downtown area were within 10 mm/year, and the largest subsidence was detected in Tongzhou, with velocities exceeding 140 mm/year. Furthermore, Gravity Recovery and Climate Experiment (GRACE) data were used to derive the groundwater change series and trend. By comparison with the multi-temporal InSAR-derived subsidence results, the long-term decreasing trend between groundwater changes and surface subsidence showed a relatively high consistency, and a significant impact of groundwater changes on the surface subsidence was identified. Additionally, the spatial distribution of the subsidence funnel was partially consistent with that of groundwater depression, i.e., the former possessed a wider range than the latter. Finally, the relationship between surface subsidence and groundwater changes was determined.

Surface Subsidence Analysis by Multi-Temporal InSAR and GRACE: A Case Study in Beijing

PubMed Central

Guo, Jiming; Zhou, Lv; Yao, Chaolong; Hu, Jiyuan

2016-01-01

The aim of this study was to investigate the relationship between surface subsidence and groundwater changes. To investigate this relationship, we first analyzed surface subsidence. This paper presents the results of a case study of surface subsidence in Beijing from 1 August 2007 to 29 September 2010. The Multi-temporal Interferometric Synthetic Aperture Radar (multi-temporal InSAR) technique, which can simultaneously detect point-like stable reflectors (PSs) and distributed scatterers (DSs), was used to retrieve the subsidence magnitude and distribution in Beijing using 18 ENVISAT ASAR images. The multi-temporal InSAR-derived subsidence was verified by leveling at an accuracy better than 5 mm/year. Based on the verified multi-temporal InSAR results, a prominent uneven subsidence was identified in Beijing. Specifically, most of the subsidence velocities in the downtown area were within 10 mm/year, and the largest subsidence was detected in Tongzhou, with velocities exceeding 140 mm/year. Furthermore, Gravity Recovery and Climate Experiment (GRACE) data were used to derive the groundwater change series and trend. By comparison with the multi-temporal InSAR-derived subsidence results, the long-term decreasing trend between groundwater changes and surface subsidence showed a relatively high consistency, and a significant impact of groundwater changes on the surface subsidence was identified. Additionally, the spatial distribution of the subsidence funnel was partially consistent with that of groundwater depression, i.e., the former possessed a wider range than the latter. Finally, the relationship between surface subsidence and groundwater changes was determined. PMID:27649183

Stable isotopic compositions in Australian precipitation

NASA Astrophysics Data System (ADS)

Liu, Jianrong; Fu, Guobin; Song, Xianfang; Charles, Stephen P.; Zhang, Yinghua; Han, Dongmei; Wang, Shiqin

2010-12-01

Stable deuterium (δD) and oxygen-18 (δ18O) isotopes in 1962 to 2002 precipitation from the seven Australian stations of the Global Network of Isotopes in Precipitation (GNIP) were used to investigate isotope characteristics including temporal and spatial distributions across different regions of Australia. On the basis of 1534 samples, the local meteoric water line (LMWL) was established as δD = 7.10δ18O + 8.21. δ18O showed a depletion trend from north and south to central Australia (a continental effect) and from west to east. Precipitation amount effects were generally greater than temperature effects, with quadratic or logarithmic correlations describing δ/T and δ/P better than linear relationships. Nonlinear stepwise regression was used to determine the significant meteorological control factors for each station, explaining about 50% or more of the δ18O variations. Geographical control factors for δ18O were given by the relationship δ18O (‰) = -0.005 longitude (°) - 0.034 latitude (°)-0.003 altitude (m) - 4.753. Four different types of d-excess patterns demonstrated particular precipitation formation conditions for four major seasonal rainfall zones. Finally, wavelet coherence (WTC) between δ18O and SOI confirmed that the influence of ENSO decreased from east and north to west Australia.

Time-Dependent Selection of an Optimal Set of Sources to Define a Stable Celestial Reference Frame

NASA Technical Reports Server (NTRS)

Le Bail, Karine; Gordon, David

2010-01-01

Temporal statistical position stability is required for VLBI sources to define a stable Celestial Reference Frame (CRF) and has been studied in many recent papers. This study analyzes the sources from the latest realization of the International Celestial Reference Frame (ICRF2) with the Allan variance, in addition to taking into account the apparent linear motions of the sources. Focusing on the 295 defining sources shows how they are a good compromise of different criteria, such as statistical stability and sky distribution, as well as having a sufficient number of sources, despite the fact that the most stable sources of the entire ICRF2 are mostly in the Northern Hemisphere. Nevertheless, the selection of a stable set is not unique: studying different solutions (GSF005a and AUG24 from GSFC and OPA from the Paris Observatory) over different time periods (1989.5 to 2009.5 and 1999.5 to 2009.5) leads to selections that can differ in up to 20% of the sources. Observing, recording, and network improvement are some of the causes, showing better stability for the CRF over the last decade than the last twenty years. But this may also be explained by the assumption of stationarity that is not necessarily right for some sources.

Stable Water Use Efficiency under Climate Change of Three Sympatric Conifer Species at the Alpine Treeline.

PubMed

Wieser, Gerhard; Oberhuber, Walter; Gruber, Andreas; Leo, Marco; Matyssek, Rainer; Grams, Thorsten Erhard Edgar

2016-01-01

The ability of treeline associated conifers in the Central Alps to cope with recent climate warming and increasing CO2 concentration is still poorly understood. We determined tree ring stable carbon and oxygen isotope ratios of Pinus cembra, Picea abies, and Larix decidua trees from 1975 to 2010. Stable isotope ratios were compared with leaf level gas exchange measurements carried out in situ between 1979 and 2007. Results indicate that tree ring derived intrinsic water-use efficiency (iWUE) of P. cembra, P. abies and L. decidua remained constant during the last 36 years despite climate warming and rising atmospheric CO2. Temporal patterns in Δ(13)C and Δ(18)O mirrored leaf level gas exchange assessments, suggesting parallel increases of CO2-fixation and stomatal conductance of treeline conifer species. As at the study site soil water availability was not a limiting factor iWUE remained largely stable throughout the study period. The stability in iWUE was accompanied by an increase in basal area increment (BAI) suggesting that treeline trees benefit from both recent climate warming and CO2 fertilization. Finally, our results suggest that iWUE may not change species composition at treeline in the Austrian Alps due to similar ecophysiological responses to climatic changes of the three sympatric study species.

Revisiting and Extending Interface Penalties for Multi-Domain Summation-by-Parts Operators

NASA Technical Reports Server (NTRS)

Carpenter, Mark H.; Nordstrom, Jan; Gottlieb, David

2007-01-01

General interface coupling conditions are presented for multi-domain collocation methods, which satisfy the summation-by-parts (SBP) spatial discretization convention. The combined interior/interface operators are proven to be L2 stable, pointwise stable, and conservative, while maintaining the underlying accuracy of the interior SBP operator. The new interface conditions resemble (and were motivated by) those used in the discontinuous Galerkin finite element community, and maintain many of the same properties. Extensive validation studies are presented using two classes of high-order SBP operators: 1) central finite difference, and 2) Legendre spectral collocation.

Compiling quantum circuits to realistic hardware architectures using temporal planners

NASA Astrophysics Data System (ADS)

Venturelli, Davide; Do, Minh; Rieffel, Eleanor; Frank, Jeremy

2018-04-01

To run quantum algorithms on emerging gate-model quantum hardware, quantum circuits must be compiled to take into account constraints on the hardware. For near-term hardware, with only limited means to mitigate decoherence, it is critical to minimize the duration of the circuit. We investigate the application of temporal planners to the problem of compiling quantum circuits to newly emerging quantum hardware. While our approach is general, we focus on compiling to superconducting hardware architectures with nearest neighbor constraints. Our initial experiments focus on compiling Quantum Alternating Operator Ansatz (QAOA) circuits whose high number of commuting gates allow great flexibility in the order in which the gates can be applied. That freedom makes it more challenging to find optimal compilations but also means there is a greater potential win from more optimized compilation than for less flexible circuits. We map this quantum circuit compilation problem to a temporal planning problem, and generated a test suite of compilation problems for QAOA circuits of various sizes to a realistic hardware architecture. We report compilation results from several state-of-the-art temporal planners on this test set. This early empirical evaluation demonstrates that temporal planning is a viable approach to quantum circuit compilation.

Classification of prostate cancer grade using temporal ultrasound: in vivo feasibility study

NASA Astrophysics Data System (ADS)

Ghavidel, Sahar; Imani, Farhad; Khallaghi, Siavash; Gibson, Eli; Khojaste, Amir; Gaed, Mena; Moussa, Madeleine; Gomez, Jose A.; Siemens, D. Robert; Leveridge, Michael; Chang, Silvia; Fenster, Aaron; Ward, Aaron D.; Abolmaesumi, Purang; Mousavi, Parvin

2016-03-01

Temporal ultrasound has been shown to have high classification accuracy in differentiating cancer from benign tissue. In this paper, we extend the temporal ultrasound method to classify lower grade Prostate Cancer (PCa) from all other grades. We use a group of nine patients with mostly lower grade PCa, where cancerous regions are also limited. A critical challenge is to train a classifier with limited aggressive cancerous tissue compared to low grade cancerous tissue. To resolve the problem of imbalanced data, we use Synthetic Minority Oversampling Technique (SMOTE) to generate synthetic samples for the minority class. We calculate spectral features of temporal ultrasound data and perform feature selection using Random Forests. In leave-one-patient-out cross-validation strategy, an area under receiver operating characteristic curve (AUC) of 0.74 is achieved with overall sensitivity and specificity of 70%. Using an unsupervised learning approach prior to proposed method improves sensitivity and AUC to 80% and 0.79. This work represents promising results to classify lower and higher grade PCa with limited cancerous training samples, using temporal ultrasound.

Spectro-Temporal Weighting of Loudness

PubMed Central

Oberfeld, Daniel; Heeren, Wiebke; Rennies, Jan; Verhey, Jesko

2012-01-01

Real-world sounds like speech or traffic noise typically exhibit spectro-temporal variability because the energy in different spectral regions evolves differently as a sound unfolds in time. However, it is currently not well understood how the energy in different spectral and temporal portions contributes to loudness. This study investigated how listeners weight different temporal and spectral components of a sound when judging its overall loudness. Spectral weights were measured for the combination of three loudness-matched narrowband noises with different center frequencies. To measure temporal weights, 1,020-ms stimuli were presented, which randomly changed in level every 100 ms. Temporal weights were measured for each narrowband noise separately, and for a broadband noise containing the combination of the three noise bands. Finally, spectro-temporal weights were measured with stimuli where the level of the three narrowband noises randomly and independently changed every 100 ms. The data consistently showed that (i) the first 300 ms of the sounds had a greater influence on overall loudness perception than later temporal portions (primacy effect), and (ii) the lowest noise band contributed significantly more to overall loudness than the higher bands. The temporal weights did not differ between the three frequency bands. Notably, the spectral weights and temporal weights estimated from the conditions with only spectral or only temporal variability were very similar to the corresponding weights estimated in the spectro-temporal condition. The results indicate that the temporal and the spectral weighting of the loudness of a time-varying sound are independent processes. The spectral weights remain constant across time, and the temporal weights do not change across frequency. The results are discussed in the context of current loudness models. PMID:23209670

Retrograde amnesia in patients with hippocampal, medial temporal, temporal lobe, or frontal pathology.

PubMed

Bright, Peter; Buckman, Joseph; Fradera, Alex; Yoshimasu, Haruo; Colchester, Alan C F; Kopelman, Michael D

2006-01-01

There is considerable controversy concerning the theoretical basis of retrograde amnesia (R.A.). In the present paper, we compare medial temporal, medial plus lateral temporal, and frontal lesion patients on a new autobiographical memory task and measures of the more semantic aspects of memory (famous faces and news events). Only those patients with damage extending beyond the medial temporal cortex into the lateral temporal regions showed severe impairment on free recall remote memory tasks, and this held for both the autobiographical and the more semantic memory tests. However, on t-test analysis, the medial temporal group was impaired in retrieving recent autobiographical memories. Within the medial temporal group, those patients who had combined hippocampal and parahippocampal atrophy (H+) on quantified MRI performed somewhat worse on the semantic tasks than those with atrophy confined to the hippocampi (H-), but scores were very similar on autobiographical episodic recall. Correlational analyses with regional MRI volumes showed that lateral temporal volume was correlated significantly with performance on all three retrograde amnesia tests. The findings are discussed in terms of consolidation, reconsolidation, and multiple trace theory: We suggest that a widely distributed network of regions underlies the retrieval of past memories, and that the extent of lateral temporal damage appears to be critical to the emergence of a severe remote memory impairment.

Methods for building an inexpensive computer-controlled olfactometer for temporally precise experiments

PubMed Central

Lundström, Johan N.; Gordon, Amy R.; Alden, Eva C.; Boesveldt, Sanne; Albrecht, Jessica

2010-01-01

Many human olfactory experiments call for fast and stable stimulus-rise times as well as exact and stable stimulus-onset times. Due to these temporal demands, an olfactometer is often needed. However, an olfactometer is a piece of equipment that either comes with a high price tag or requires a high degree of technical expertise to build and/or to run. Here, we detail the construction of an olfactometer that is constructed almost exclusively with “off-the-shelf” parts, requires little technical knowledge to build, has relatively low price tags, and is controlled by E-Prime, a turnkey-ready and easily-programmable software commonly used in psychological experiments. The olfactometer can present either solid or liquid odor sources, and it exhibits a fast stimulus-rise time and a fast and stable stimulus-onset time. We provide a detailed description of the olfactometer construction, a list of its individual parts and prices, as well as potential modifications to the design. In addition, we present odor onset and concentration curves as measured with a photoionization detector, together with corresponding GC/MS analyses of signal-intensity drop (5.9%) over a longer period of use. Finally, we present data from behavioral and psychophysiological recordings demonstrating that the olfactometer is suitable for use during event-related EEG experiments. PMID:20688109

Towards highly stable polymer electronics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Nikolka, Mark; Nasrallah, Iyad; Broch, Katharina; Sadhanala, Aditya; Hurhangee, Michael; McCulloch, Iain; Sirringhaus, Henning

2016-11-01

Due to their ease of processing, organic semiconductors are promising candidates for applications in high performance flexible displays and fast organic electronic circuitry. Recently, a lot of advances have been made on organic semiconductors exhibiting surprisingly high performance and carrier mobilities exceeding those of amorphous silicon. However, there remain significant concerns about their operational and environmental stability, particularly in the context of applications that require a very high level of threshold voltage stability, such as active-matrix addressing of organic light-emitting diode (OLED) displays. Here, we report a novel technique for dramatically improving the operational stress stability, performance and uniformity of high mobility polymer field-effect transistors by the addition of specific small molecule additives to the polymer semiconductor film. We demonstrate for the first time polymer FETs that exhibit stable threshold voltages with threshold voltage shifts of less than 1V when subjected to a constant current operational stress for 1 day under conditions that are representative for applications in OLED active matrix displays. The approach constitutes in our view a technological breakthrough; it also makes the device characteristics independent of the atmosphere in which it is operated, causes a significant reduction in contact resistance and significantly improves device uniformity. We will discuss in detail the microscopic mechanism by which the molecular additives lead to this significant improvement in device performance and stability.

Air-stable memory array of bistable rectifying diodes based on ferroelectric-semiconductor polymer blends

NASA Astrophysics Data System (ADS)

Kumar, Manasvi; Sharifi Dehsari, Hamed; Anwar, Saleem; Asadi, Kamal

2018-03-01

Organic bistable diodes based on phase-separated blends of ferroelectric and semiconducting polymers have emerged as promising candidates for non-volatile information storage for low-cost solution processable electronics. One of the bottlenecks impeding upscaling is stability and reliable operation of the array in air. Here, we present a memory array fabricated with an air-stable amine-based semiconducting polymer. Memory diode fabrication and full electrical characterizations were carried out in atmospheric conditions (23 °C and 45% relative humidity). The memory diodes showed on/off ratios greater than 100 and further exhibited robust and stable performance upon continuous write-read-erase-read cycles. Moreover, we demonstrate a 4-bit memory array that is free from cross-talk with a shelf-life of several months. Demonstration of the stability and reliable air operation further strengthens the feasibility of the resistance switching in ferroelectric memory diodes for low-cost applications.

Hadamard Factorization of Stable Polynomials

NASA Astrophysics Data System (ADS)

Loredo-Villalobos, Carlos Arturo; Aguirre-Hernández, Baltazar

2011-11-01

The stable (Hurwitz) polynomials are important in the study of differential equations systems and control theory (see [7] and [19]). A property of these polynomials is related to Hadamard product. Consider two polynomials p,q ∈ R[x]:p(x) = anxn+an-1xn-1+...+a1x+a0q(x) = bmx m+bm-1xm-1+...+b1x+b0the Hadamard product (p × q) is defined as (p×q)(x) = akbkxk+ak-1bk-1xk-1+...+a1b1x+a0b0where k = min(m,n). Some results (see [16]) shows that if p,q ∈R[x] are stable polynomials then (p×q) is stable, also, i.e. the Hadamard product is closed; however, the reciprocal is not always true, that is, not all stable polynomial has a factorization into two stable polynomials the same degree n, if n> 4 (see [15]).In this work we will give some conditions to Hadamard factorization existence for stable polynomials.

Freshwater Recirculating Aquaculture System Operations Drive Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira

PubMed Central

Bartelme, Ryan P.; McLellan, Sandra L.; Newton, Ryan J.

2017-01-01

Recirculating aquaculture systems (RAS) are unique engineered ecosystems that minimize environmental perturbation by reducing nutrient pollution discharge. RAS typically employ a biofilter to control ammonia levels produced as a byproduct of fish protein catabolism. Nitrosomonas (ammonia-oxidizing), Nitrospira, and Nitrobacter (nitrite-oxidizing) species are thought to be the primary nitrifiers present in RAS biofilters. We explored this assertion by characterizing the biofilter bacterial and archaeal community of a commercial scale freshwater RAS that has been in operation for >15 years. We found the biofilter community harbored a diverse array of bacterial taxa (>1000 genus-level taxon assignments) dominated by Chitinophagaceae (~12%) and Acidobacteria (~9%). The bacterial community exhibited significant composition shifts with changes in biofilter depth and in conjunction with operational changes across a fish rearing cycle. Archaea also were abundant, and were comprised solely of a low diversity assemblage of Thaumarchaeota (>95%), thought to be ammonia-oxidizing archaea (AOA) from the presence of AOA ammonia monooxygenase genes. Nitrosomonas were present at all depths and time points. However, their abundance was >3 orders of magnitude less than AOA and exhibited significant depth-time variability not observed for AOA. Phylogenetic analysis of the nitrite oxidoreductase beta subunit (nxrB) gene indicated two distinct Nitrospira populations were present, while Nitrobacter were not detected. Subsequent identification of Nitrospira ammonia monooxygenase alpha subunit genes in conjunction with the phylogenetic placement and quantification of the nxrB genotypes suggests complete ammonia-oxidizing (comammox) and nitrite-oxidizing Nitrospira populations co-exist with relatively equivalent and stable abundances in this system. It appears RAS biofilters harbor complex microbial communities whose composition can be affected directly by typical system operations while

Is long-term ecological functioning stable: The case of the marine benthos?

NASA Astrophysics Data System (ADS)

Frid, C. L. J.; Caswell, B. A.

2015-04-01

It is widely acknowledged that human activities are contributing to substantial biodiversity loss and that this threatens ecological processes underpinning human exploitation of 'ecosystem services' (defined by the Millennium Ecosystem Assessment as 'the benefits people obtain from ecosystems'). In the present study we consider three 'intermediate ecosystem services' in both contemporary and ancient marine systems and although 'ecosystem services' per se did not exist in the Jurassic our study seeks to consider the future provision of these services and so the term is retained. We consider the temporal patterns in benthic marine ecosystems: (1) spanning four decades at two offshore stations in the North Sea, UK and (2) over millennial scales in Late Jurassic UK palaeocommunities. Biological traits analysis is used to link changes in taxonomic composition to variations in ecological functioning and the potential supply of three 'intermediate' ecosystem services: the ability to provide food to fish and other predators, benthic nutrient regeneration and carbon cycling. We examine whether changes in taxonomic composition drive temporal variation in functioning, whether this variation increases over time and the extent to which species turnover is comparable in contemporary and ancient systems. Taxonomic variability was of a similar magnitude in all three systems and there was evidence for changes in functioning linked to changes in several (key or rivet) taxa. During other periods resilience maintained functioning in the face of taxonomic change. These results suggest that in these benthic systems the Biodiversity-Ecosystem Functioning relationship is idiosyncratic, but a degree of temporal stability in functioning is maintained such that the ecosystem services they underpin would also be stable during decadal and longer-term changes.

Stable “Trait” Variance of Temperament as a Predictor of the Temporal Course of Depression and Social Phobia

PubMed Central

Naragon-Gainey, Kristin; Gallagher, Matthew W.; Brown, Timothy A.

2013-01-01

A large body of research has found robust associations between dimensions of temperament (e.g., neuroticism, extraversion) and the mood and anxiety disorders. However, mood-state distortion (i.e., the tendency for current mood state to bias ratings of temperament) likely confounds these associations, rendering their interpretation and validity unclear. This issue is of particular relevance to clinical populations who experience elevated levels of general distress. The current study used the “trait-state-occasion” latent variable model (Cole, Martin, & Steiger, 2005) to separate the stable components of temperament from transient, situational influences such as current mood state. We examined the predictive power of the time-invariant components of temperament on the course of depression and social phobia in a large, treatment-seeking sample with mood and/or anxiety disorders (N = 826). Participants were assessed three times over the course of one year, using interview and self-report measures; most participants received treatment during this time. Results indicated that both neuroticism/behavioral inhibition (N/BI) and behavioral activation/positive affect (BA/P) consisted largely of stable, time-invariant variance (57% to 78% of total variance). Furthermore, the time-invariant components of N/BI and BA/P were uniquely and incrementally predictive of change in depression and social phobia, adjusting for initial symptom levels. These results suggest that the removal of state variance bolsters the effect of temperament on psychopathology among clinically distressed individuals. Implications for temperament-psychopathology models, psychopathology assessment, and the stability of traits are discussed. PMID:24016004

Efficient and Stable Silicon Microwire Photocathodes with a Nickel Silicide Interlayer for Operation in Strongly Alkaline Solutions.

PubMed

Vijselaar, Wouter; Tiggelaar, Roald M; Gardeniers, Han; Huskens, Jurriaan

2018-05-11

Most photoanodes commonly applied in solar fuel research (e.g., of Fe 2 O 3 , BiVO 4 , TiO 2 , or WO 3 ) are only active and stable in alkaline electrolytes. Silicon (Si)-based photocathodes on the other hand are mainly studied under acidic conditions due to their instability in alkaline electrolytes. Here, we show that the in-diffusion of nickel into a 3D Si structure, upon thermal annealing, yields a thin (sub-100 nm), defect-free nickel silicide (NiSi) layer. This has allowed us to design and fabricate a Si microwire photocathode with a NiSi interlayer between the catalyst and the Si microwires. Upon electrodeposition of the catalyst (here, nickel molybdenum) on top of the NiSi layer, an efficient, Si-based photocathode was obtained that is stable in strongly alkaline solutions (1 M KOH). The best-performing, all-earth-abundant microwire array devices exhibited, under AM 1.5G simulated solar illumination, an ideal regenerative cell efficiency of 10.1%.

Long-term data set analysis of stable isotopic composition in German rivers

NASA Astrophysics Data System (ADS)

Reckerth, Anne; Stichler, Willibald; Schmidt, Axel; Stumpp, Christine

2017-09-01

Stable isotopes oxygen-18 (18O) and deuterium (2H) are commonly used to investigate hydrological processes in catchments. However, only a few isotope studies have been conducted on a large scale and rarely over long time periods. The objective of this study was to identify the spatial and seasonal variability of isotopic composition in river water and how it is affected by geographical and hydrological factors. The stable isotopic composition of river water has been measured in nine large river catchments in Germany for a time period of 12 years or 26 years. We conducted time series and correlation analyses to identify spatial and temporal patterns of the isotopic composition in the rivers. Further, we compared it to isotopic composition in local precipitation and catchments characteristics. In the majority of the rivers, the spatial and temporal patterns of precipitation were directly reflected in river water. The isotopic signals of the river water were time shifted and show attenuated amplitudes. Further deviations from isotopic compositions in local precipitation were observed in catchments with complex flow systems. These deviations were attributed to catchment processes and influences like evaporation, damming and storage. The seasonality of the isotopic composition was mainly determined by the discharge regimes of the rivers. We found correlations between isotopic long-term averages and catchment altitude as well as latitude and longitude, resulting in a northwest-southeast gradient. Furthermore, it was shown that long-term averages of d-excess were inversely related to flow length and catchment size, which indicates that evaporation enrichment has an impact on the isotopic composition even in catchments of humid climates. This study showed that isotopic composition in rivers can serve as a proxy for the local precipitation and can be utilized as an indicator for hydrological processes even in large river basins. In future, such long time series will help to

Predicting ICU mortality: a comparison of stationary and nonstationary temporal models.

PubMed Central

Kayaalp, M.; Cooper, G. F.; Clermont, G.

2000-01-01

OBJECTIVE: This study evaluates the effectiveness of the stationarity assumption in predicting the mortality of intensive care unit (ICU) patients at the ICU discharge. DESIGN: This is a comparative study. A stationary temporal Bayesian network learned from data was compared to a set of (33) nonstationary temporal Bayesian networks learned from data. A process observed as a sequence of events is stationary if its stochastic properties stay the same when the sequence is shifted in a positive or negative direction by a constant time parameter. The temporal Bayesian networks forecast mortalities of patients, where each patient has one record per day. The predictive performance of the stationary model is compared with nonstationary models using the area under the receiver operating characteristics (ROC) curves. RESULTS: The stationary model usually performed best. However, one nonstationary model using large data sets performed significantly better than the stationary model. CONCLUSION: Results suggest that using a combination of stationary and nonstationary models may predict better than using either alone. PMID:11079917

Psychiatric consequences of temporal lobectomy for intractable seizures: a 20-30-year follow-up of 14 cases.

PubMed

Stevens, J R

1990-08-01

Between 1958 and 1968, 14 patients from the epilepsy clinic at the University of Oregon Hospitals and Clinics with a diagnosis of temporal lobe epilepsy (TLE) had a temporal lobectomy for medically intractable seizures. Nine of the 14 patients operated on remained seizure-free over the 20-30-year period of follow-up. Between 6 months and one year following temporal lobectomy, two women, previously healthy from a psychiatric standpoint, developed psychoses, and the previous psychiatric problems of four other patients worsened. Two patients, one with incapacitating paranoid personality disorder and the other with explosive rage attacks preoperatively, had marked improvement in their psychiatric status following temporal lobectomy. The remaining six patients, all psychiatrically healthy prior to surgery, have had no change in psychiatric status following surgery. Development of psychosis or deterioration in psychiatric status after surgery was more common in patients with later age of onset, unreality or déjà vu rather than epigastric aura, pre-operative evidence of bilateral brain damage, and persistence of EEG or clinical seizure activity. Development of a chronic psychosis in psychiatrically healthy individuals many months after temporal lobectomy, even when seizures are arrested or ameliorated, suggests that anomalous synaptic regeneration may follow the surgery in these cases. Careful analysis of histories and outcomes may contribute to better understanding of the pathophysiology and anatomical substrates of psychoses.

Operational Impacts of Operating Reserve Demand Curves on Production Cost and Reliability: Preprint

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

Krad, Ibrahim; Ibanez, Eduardo; Ela, Erik

The electric power industry landscape is continually evolving. As emerging technologies such as wind, solar, electric vehicles, and energy storage systems become more cost-effective and present in the system, traditional power system operating strategies will need to be reevaluated. The presence of wind and solar generation (commonly referred to as variable generation) may result in an increase in the variability and uncertainty of the net load profile. One mechanism to mitigate this is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increasedmore » variability and uncertainty occurring at finer temporal resolutions. A new operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this paper, and its implications on power system operations are analyzed.« less

The course of language functions after temporal lobe epilepsy surgery: a prospective study.

PubMed

Giovagnoli, A R; Parente, A; Didato, G; Manfredi, V; Deleo, F; Tringali, G; Villani, F

2016-12-01

Anterior temporal lobectomy (ATL) within the language-dominant hemisphere can impair naming. This prospective study examined the pre-operative to post-operative course of different language components, clarifying which changes are relevant within the short-term and long-term outcome of language. Patients with drug-resistant temporal lobe epilepsy (TLE) were evaluated using the Token, Boston Naming and Word Fluency tests assessing sentence comprehension and word-finding on visual, semantic or phonemic cues. A total of 106 patients were evaluated before and 6 months, 1 and 2 years after ATL; 60 patients were also evaluated after 5 years and 38 controls were assessed at baseline. Seizure outcome was comparable between the left and right TLE patients. Before surgery, naming and word fluency were impaired in the left and right TLE patients, whereas sentence comprehension was normal. After left or right ATL, word fluency progressively improved, naming showed early worsening and late improvement after left ATL and progressive improvement after right ATL, and sentence comprehension did not change. At the 5-year follow-up, naming improvement was clinically significant in 31% and 71% of the left and right TLE patients, respectively. Pre-operative naming, ATL laterality, schooling, and post-operative seizure frequency and number of antiepileptic drugs predicted post-operative naming. Pre-operative word fluency and schooling predicted post-operative word fluency. Left or right TLE can impair word-finding but not sentence comprehension. After ATL, word-finding may improve for a long time, depending on TLE laterality, seizure control and mental reserve. These findings may clarify prognosis prior to treatment. © 2016 EAN.

Natural world physical, brain operational, and mind phenomenal space-time

NASA Astrophysics Data System (ADS)

Fingelkurts, Andrew A.; Fingelkurts, Alexander A.; Neves, Carlos F. H.

2010-06-01

Concepts of space and time are widely developed in physics. However, there is a considerable lack of biologically plausible theoretical frameworks that can demonstrate how space and time dimensions are implemented in the activity of the most complex life-system - the brain with a mind. Brain activity is organized both temporally and spatially, thus representing space-time in the brain. Critical analysis of recent research on the space-time organization of the brain's activity pointed to the existence of so-called operational space-time in the brain. This space-time is limited to the execution of brain operations of differing complexity. During each such brain operation a particular short-term spatio-temporal pattern of integrated activity of different brain areas emerges within related operational space-time. At the same time, to have a fully functional human brain one needs to have a subjective mental experience. Current research on the subjective mental experience offers detailed analysis of space-time organization of the mind. According to this research, subjective mental experience (subjective virtual world) has definitive spatial and temporal properties similar to many physical phenomena. Based on systematic review of the propositions and tenets of brain and mind space-time descriptions, our aim in this review essay is to explore the relations between the two. To be precise, we would like to discuss the hypothesis that via the brain operational space-time the mind subjective space-time is connected to otherwise distant physical space-time reality.

Temporal stability of visual search-driven biometrics

NASA Astrophysics Data System (ADS)

Yoon, Hong-Jun; Carmichael, Tandy R.; Tourassi, Georgia

2015-03-01

Previously, we have shown the potential of using an individual's visual search pattern as a possible biometric. That study focused on viewing images displaying dot-patterns with different spatial relationships to determine which pattern can be more effective in establishing the identity of an individual. In this follow-up study we investigated the temporal stability of this biometric. We performed an experiment with 16 individuals asked to search for a predetermined feature of a random-dot pattern as we tracked their eye movements. Each participant completed four testing sessions consisting of two dot patterns repeated twice. One dot pattern displayed concentric circles shifted to the left or right side of the screen overlaid with visual noise, and participants were asked which side the circles were centered on. The second dot-pattern displayed a number of circles (between 0 and 4) scattered on the screen overlaid with visual noise, and participants were asked how many circles they could identify. Each session contained 5 untracked tutorial questions and 50 tracked test questions (200 total tracked questions per participant). To create each participant's "fingerprint", we constructed a Hidden Markov Model (HMM) from the gaze data representing the underlying visual search and cognitive process. The accuracy of the derived HMM models was evaluated using cross-validation for various time-dependent train-test conditions. Subject identification accuracy ranged from 17.6% to 41.8% for all conditions, which is significantly higher than random guessing (1/16 = 6.25%). The results suggest that visual search pattern is a promising, temporally stable personalized fingerprint of perceptual organization.

A novel cross-satellite based assessment of the spatio-temporal development of a cyanobacterial harmful algal bloom

NASA Astrophysics Data System (ADS)

Page, Benjamin P.; Kumar, Abhishek; Mishra, Deepak R.

2018-04-01

As the frequency of cyanobacterial harmful algal blooms (CyanoHABs) become more common in recreational lakes and water supply reservoirs, demand for rapid detection and temporal monitoring will be imminent for effective management. The goal of this study was to demonstrate a novel and potentially operational cross-satellite based protocol for synoptic monitoring of rapidly evolving and increasingly common CyanoHABs in inland waters. The analysis involved a novel way to cross-calibrate a chlorophyll-a (Chl-a) detection model for the Landsat-8 OLI sensor from the relationship between the normalized difference chlorophyll index and the floating algal index derived from Sentinel-2A on a coinciding overpass date during the summer CyanoHAB bloom in Utah Lake. This aided in the construction of a time-series phenology of the Utah Lake CyanoHAB event. Spatio-temporal cyanobacterial density maps from both Sentinel-2A and Landsat-8 sensors revealed that the bloom started in the first week of July 2016 (July 3rd, mean cell count: 9163 cells/mL), reached peak in mid-July (July 15th, mean cell count: 108176 cells/mL), and reduced in August (August 24th, mean cell count: 9145 cells/mL). Analysis of physical and meteorological factors suggested a complex interaction between landscape processes (high surface runoff), climatic conditions (high temperature, high rainfall followed by negligible rainfall, stable wind), and water quality (low water level, high Chl-a) which created a supportive environment for triggering these blooms in Utah Lake. This cross satellite-based monitoring methods can be a great tool for regular monitoring and will reduce the budget cost for monitoring and predicting CyanoHABs in large lakes.

A semigroup approach to the strong ergodic theorem of the multistate stable population process.

PubMed

Inaba, H

1988-01-01

"In this paper we first formulate the dynamics of multistate stable population processes as a partial differential equation. Next, we rewrite this equation as an abstract differential equation in a Banach space, and solve it by using the theory of strongly continuous semigroups of bounded linear operators. Subsequently, we investigate the asymptotic behavior of this semigroup to show the strong ergodic theorem which states that there exists a stable distribution independent of the initial distribution. Finally, we introduce the dual problem in order to obtain a logical definition for the reproductive value and we discuss its applications." (SUMMARY IN FRE) excerpt

Spatial and Temporal Variation of Archaeal, Bacterial and Fungal Communities in Agricultural Soils

PubMed Central

Pereira e Silva, Michele C.; Dias, Armando Cavalcante Franco; van Elsas, Jan Dirk; Salles, Joana Falcão

2012-01-01

Background Soil microbial communities are in constant change at many different temporal and spatial scales. However, the importance of these changes to the turnover of the soil microbial communities has been rarely studied simultaneously in space and time. Methodology/Principal Findings In this study, we explored the temporal and spatial responses of soil bacterial, archaeal and fungal β-diversities to abiotic parameters. Taking into account data from a 3-year sampling period, we analyzed the abundances and community structures of Archaea, Bacteria and Fungi along with key soil chemical parameters. We questioned how these abiotic variables influence the turnover of bacterial, archaeal and fungal communities and how they impact the long-term patterns of changes of the aforementioned soil communities. Interestingly, we found that the bacterial and fungal β-diversities are quite stable over time, whereas archaeal diversity showed significantly higher fluctuations. These fluctuations were reflected in temporal turnover caused by soil management through addition of N-fertilizers. Conclusions Our study showed that management practices applied to agricultural soils might not significantly affect the bacterial and fungal communities, but cause slow and long-term changes in the abundance and structure of the archaeal community. Moreover, the results suggest that, to different extents, abiotic and biotic factors determine the community assembly of archaeal, bacterial and fungal communities. PMID:23284712

Performance metric comparison study for non-magnetic bi-stable energy harvesters

NASA Astrophysics Data System (ADS)

Udani, Janav P.; Wrigley, Cailin; Arrieta, Andres F.

2017-04-01

Energy harvesting employing non-linear systems offers considerable advantages over linear systems given the broadband resonant response which is favorable for applications involving diverse input vibrations. In this respect, the rich dynamics of bi-stable systems present a promising means for harvesting vibrational energy from ambient sources. Harvesters deriving their bi-stability from thermally induced stresses as opposed to magnetic forces are receiving significant attention as it reduces the need for ancillary components and allows for bio- compatible constructions. However, the design of these bi-stable harvesters still requires further optimization to completely exploit the dynamic behavior of these systems. This study presents a comparison of the harvesting capabilities of non-magnetic, bi-stable composite laminates under variations in the design parameters as evaluated utilizing established power metrics. Energy output characteristics of two bi-stable composite laminate plates with a piezoelectric patch bonded on the top surface are experimentally investigated for variations in the thickness ratio and inertial mass positions for multiple load conditions. A particular design configuration is found to perform better over the entire range of testing conditions which include single and multiple frequency excitation, thus indicating that design optimization over the geometry of the harvester yields robust performance. The experimental analysis further highlights the need for appropriate design guidelines for optimization and holistic performance metrics to account for the range of operational conditions.

Steady-state inductive spheromak operation

DOEpatents

Janos, A.C.; Jardin, S.C.; Yamada, M.

1985-02-20

The inductively formed spheromak configuration (S-1) can be maintained in a highly stable and controlled fashion. The method described eliminates the restriction to pulsed spheromak plasmas or the use of electrodes for steady-state operation, and, therefore, is a reactor-relevant formation and sustainment method.

SPORT: Radiographic Predictors of Clinical Outcomes Following Operative or Non-operative Treatment of Degenerative Spondylolisthesis

PubMed Central

Pearson, Adam M.; Lurie, Jon D.; Blood, Emily A.; Frymoyer, John W.; Braeutigam, Heike; An, Howard; Girardi, Federico P.; Weinstein, James N.

2009-01-01

STUDY DESIGN Subgroup analyses according to treatment received. OBJECTIVES To evaluate whether baseline radiographic findings predicted outcomes in patients with degenerative spondylolisthesis (DS). SUMMARY OF BACKGROUND DATA The SPORT combined randomized and observational DS cohorts. METHODS The Meyerding listhesis grade was determined on the neutral radiograph (n=222). Patients were classified as having low disk height if disk height was less than 5 mm. Flexion-extension radiographs (n=185) were evaluated for mobility. Those with greater than 10° rotation or 4mm translation were considered Hypermobile. Changes in outcome measures were compared between listhesis (Grade 1 vs. Grade 2), disk height (Low vs. Normal) and mobility (Stable vs. Hypermobile) groups using longitudinal regression models adjusted for potential confounders. Outcome measures included SF-36 bodily pain (BP) and physical function (PF) scales, Oswestry disability index (ODI), stenosis bothersomeness index (SBI), and low back pain bothersomeness scale. RESULTS Overall, 86% had a Grade 1 listhesis, 78% had Normal disk height, and 73% were Stable. Baseline symptom severity was similar between groups. Overall, surgery patients improved more than patients treated non-operatively. At one year, outcomes were similar in surgery patients across listhesis, disk height, and mobility groups (ODI: Grade 1 -23.7 vs. Grade 2 -23.3, p=0.90; Normal disk height-23.5 vs. Low disk height -21.9, p=0.66; Stable -21.6 vs. Hypermobile -25.2, p=0.30). Among those treated nonoperatively, Grade 1 patients improved more than Grade 2 patients (BP +13.1 vs. -4.9, p=0.019; ODI -8.0 vs. +4.8, p=0.010 at 1 year), and Hypermobile patients improved more than Stable patients (ODI -15.2 vs -6.6, p=0.041; SBI -7.8 vs -2.7, p=0.002 at 1 year). DISCUSSION Regardless of listhesis grade, disk height or mobility, patients who had surgery improved more than those treated non-operatively. These differences were due, in part, to differences

Knowledge acquisition for temporal abstraction.

PubMed

Stein, A; Musen, M A; Shahar, Y

1996-01-01

Temporal abstraction is the task of detecting relevant patterns in data over time. The knowledge-based temporal-abstraction method uses knowledge about a clinical domain's contexts, external events, and parameters to create meaningful interval-based abstractions from raw time-stamped clinical data. In this paper, we describe the acquisition and maintenance of domain-specific temporal-abstraction knowledge. Using the PROTEGE-II framework, we have designed a graphical tool for acquiring temporal knowledge directly from expert physicians, maintaining the knowledge in a sharable form, and converting the knowledge into a suitable format for use by an appropriate problem-solving method. In initial tests, the tool offered significant gains in our ability to rapidly acquire temporal knowledge and to use that knowledge to perform automated temporal reasoning.

Temporal waveguides for optical pulses

DOE PAGES

Plansinis, Brent W.; Donaldson, William R.; Agrawal, Govind P.

2016-05-12

Here we discuss, temporal total internal reflection (TIR), in analogy to the conventional TIR of an optical beam at a dielectric interface, is the total reflection of an optical pulse inside a dispersive medium at a temporal boundary across which the refractive index changes. A pair of such boundaries separated in time acts as the temporal analog of planar dielectric waveguides. We study the propagation of optical pulses inside such temporal waveguides, both analytically and numerically, and show that the waveguide supports a finite number of temporal modes. We also discuss how a single-mode temporal waveguide can be created inmore » practice. In contrast with the spatial case, the confinement can occur even when the central region has a lower refractive index.« less

Modelling stable water isotopes during "high-precipitation" events at Dome C, Antarctica

NASA Astrophysics Data System (ADS)

Schlosser, Elisabeth; Masson-Delmotte, Valérie; Risi, Camille; Stenni, Barbara; Valt, Mauro; Powers, Jordan G.; Manning, Kevin W.; Duda, Michael G.; Cagnati, Anselmo

2014-05-01

For a correct paleoclimatologic interpretation of stable water isotopes from ice cores both pre- and post-depositional processes and their role for isotope fractionation have to be better understood. Our study focusses on "pre-depositional processes", namely the atmospheric processes that determine moisture transport and precipitation formation. At the deep ice core drilling site "Dome C", East Antarctica, fresh snow samples have been taken since 2006. These samples have been analysed crystallographically, which enables us to clearly distinguish between blowing snow, diamond dust, and "synoptic precipitation". Also the stable oxygen/hydrogen isotope ratios of the snow samples were measured, including measurements of 17-O. This is the first and only multi-year fresh-snow data series from an Antarctic deep drilling site. The Antarctic Mesoscale Prediction System (AMPS) employs Polar WRF for aviation weather forecasts in Antarctica. The data are archived and can be used for scientific purposes. The mesoscale atmospheric model was adapted especially for polar regions. The horizontal resolution for the domain that covers the Antarctic continent is 10 km. It was shown that precipitation at Dome C is temporally dominated by diamond dust. However, comparatively large amounts of precipitation are observed during several "high-precipitation" events per year, caused by synoptic activity in the circumpolar trough and related advection of relatively warm and moist air from lower latitudes to the interior of Antarctica. AMPS archive data are used to investigate the synoptic situations that lead to "high-precipitation" events at Dome C; in particular, possible moisture sources are determined using back-trajectories. With this meteorological information, the isotope ratios are calculated using two different isotope models, the Mixed Cloud Isotope Model, a simple Rayleigh-type model, and the LMDZ-iso (Laboratoire de Météorologie Dynamic Zoom), a General Circulation Model (GCM

[Children's oppositional behaviour, practice of parental authority and temporal anomie].

PubMed

Gadeau, L

2014-02-01

This article examines the relationship between children's oppositional behaviour and the exercise of parental authority. It seeks to explore the value of a heuristic approach to psychic temporality in exercising parental authority. The study aims to better understand the role of psychic temporality in operations producing symbolic law. It goes on to describe a disorder of temporality, known as temporal anomie, which may be involved in a child's oppositional disorders. Psychiatric or psychological consultations motivated by oppositional disorders in children have increased steadily in the past fifteen years in France. The primary reason for consultation is in the form of difficulties for children in accepting the social rules or constraints, but also the difficulties of parenting while coping with the opposition of their children. This increase is made in connection with the works analysing the social and psychological effects imposed by modernity and its acceleration. Correspondingly, we find that some parents do not prioritize their educational requirements, do not know when or how to frustrate their child, or even if it is legitimate to expect from him/her a certain type of behaviour. They seem more preoccupied with the fear of not being loved by their child more than their duty to educate. A general trend suggests an alteration of psychological time, characterized by: a) a disinvestment of links between present and past for the enjoyment of the moment and its extension in the immediate future ; b) a difficulty in supporting educational responses causing frustration for the child ; c) a lack of continuity and constancy in educational requirements. The author proposes to define temporal anomie as the psychical time that weakens the consistency of educational responses. A link between psychological temporality and the symbolic law is discussed. Specifically, the study notes that: in intersubjective relations, mastery of psychological time by parents is an

Temporal texture of associative encoding modulates recall processes.

PubMed

Tibon, Roni; Levy, Daniel A

2014-02-01

Binding aspects of an experience that are distributed over time is an important element of episodic memory. In the current study, we examined how the temporal complexity of an experience may govern the processes required for its retrieval. We recorded event-related potentials during episodic cued recall following pair associate learning of concurrently and sequentially presented object-picture pairs. Cued recall success effects over anterior and posterior areas were apparent in several time windows. In anterior locations, these recall success effects were similar for concurrently and sequentially encoded pairs. However, in posterior sites clustered over parietal scalp the effect was larger for the retrieval of sequentially encoded pairs. We suggest that anterior aspects of the mid-latency recall success effects may reflect working-with-memory operations or direct access recall processes, while more posterior aspects reflect recollective processes which are required for retrieval of episodes of greater temporal complexity. Copyright © 2013 Elsevier Inc. All rights reserved.

Temporally coherent 4D video segmentation for teleconferencing

NASA Astrophysics Data System (ADS)

Ehmann, Jana; Guleryuz, Onur G.

2013-09-01

We develop an algorithm for 4-D (RGB+Depth) video segmentation targeting immersive teleconferencing ap- plications on emerging mobile devices. Our algorithm extracts users from their environments and places them onto virtual backgrounds similar to green-screening. The virtual backgrounds increase immersion and interac- tivity, relieving the users of the system from distractions caused by disparate environments. Commodity depth sensors, while providing useful information for segmentation, result in noisy depth maps with a large number of missing depth values. By combining depth and RGB information, our work signi¯cantly improves the other- wise very coarse segmentation. Further imposing temporal coherence yields compositions where the foregrounds seamlessly blend with the virtual backgrounds with minimal °icker and other artifacts. We achieve said improve- ments by correcting the missing information in depth maps before fast RGB-based segmentation, which operates in conjunction with temporal coherence. Simulation results indicate the e±cacy of the proposed system in video conferencing scenarios.

Ultrafast and versatile spectroscopy by temporal Fourier transform

NASA Astrophysics Data System (ADS)

Zhang, Chi; Wei, Xiaoming; Marhic, Michel E.; Wong, Kenneth K. Y.

2014-06-01

One of the most remarkable and useful properties of a spatially converging lens system is its inherent ability to perform the Fourier transform; the same applies for the time-lens system. At the back focal plane of the time-lens, the spectral information can be instantaneously obtained in the time axis. By implementing temporal Fourier transform for spectroscopy applications, this time-lens-based architecture can provide orders of magnitude improvement over the state-of-art spatial-dispersion-based spectroscopy in terms of the frame rate. On the other hand, in addition to the single-lens structure, the multi-lens structures (e.g. telescope or wide-angle scope) will provide very versatile operating conditions. Leveraging the merit of instantaneous response, as well as the flexible lens structure, here we present a 100-MHz frame rate spectroscopy system - the parametric spectro-temporal analyzer (PASTA), which achieves 17 times zoom in/out ratio for different observation ranges.

Devices and methods of operation thereof for providing stable flow for centrifugal compressors

NASA Technical Reports Server (NTRS)

Skoch, Gary J. (Inventor); Stevens, Mark A. (Inventor); Jett, Thomas A. (Inventor)

2008-01-01

Centrifugal compressor flow stabilizing devices and methods of operation thereof are disclosed that act upon the flow field discharging from the impeller of a centrifugal compressor and modify the flow field ahead of the diffuser vanes such that flow conditions contributing to rotating stall and surge are reduced or even eliminated. In some embodiments, shaped rods and methods of operation thereof are disclosed, whereas in other embodiments reverse-tangent air injection devices and methods are disclosed.

Spatiotemporal attention operator using isotropic contrast and regional homogeneity

NASA Astrophysics Data System (ADS)

Palenichka, Roman; Lakhssassi, Ahmed; Zaremba, Marek

2011-04-01

A multiscale operator for spatiotemporal isotropic attention is proposed to reliably extract attention points during image sequence analysis. Its consecutive local maxima indicate attention points as the centers of image fragments of variable size with high intensity contrast, region homogeneity, regional shape saliency, and temporal change presence. The scale-adaptive estimation of temporal change (motion) and its aggregation with the regional shape saliency contribute to the accurate determination of attention points in image sequences. Multilocation descriptors of an image sequence are extracted at the attention points in the form of a set of multidimensional descriptor vectors. A fast recursive implementation is also proposed to make the operator's computational complexity independent from the spatial scale size, which is the window size in the spatial averaging filter. Experiments on the accuracy of attention-point detection have proved the operator consistency and its high potential for multiscale feature extraction from image sequences.

Graph theoretical stable allocation as a tool for reproduction of control by human operators

NASA Astrophysics Data System (ADS)

van Nooijen, Ronald; Ertsen, Maurits; Kolechkina, Alla

2016-04-01

During the design of central control algorithms for existing water resource systems under manual control it is important to consider the interaction with parts of the system that remain under manual control and to compare the proposed new system with the existing manual methods. In graph theory the "stable allocation" problem has good solution algorithms and allows for formulation of flow distribution problems in terms of priorities. As a test case for the use of this approach we used the algorithm to derive water allocation rules for the Gezira Scheme, an irrigation system located between the Blue and White Niles south of Khartoum. In 1925, Gezira started with 300,000 acres; currently it covers close to two million acres.

Temporal Stress in the Operating Room: Brain Engagement Promotes "Coping" and Disengagement Prompts "Choking".

PubMed

Modi, Hemel N; Singh, Harsimrat; Orihuela-Espina, Felipe; Athanasiou, Thanos; Fiorentino, Francesca; Yang, Guang-Zhong; Darzi, Ara; Leff, Daniel R

2018-04-01

To investigate the impact of time pressure (TP) on prefrontal activation and technical performance in surgical residents during a laparoscopic suturing task. Neural mechanisms enabling surgeons to maintain performance and cope with operative stressors are unclear. The prefrontal cortex (PFC) is implicated due to its role in attention, concentration, and performance monitoring. A total of 33 residents [Postgraduate Year (PGY)1-2 = 15, PGY3-4 = 8, and PGY5 = 10] performed a laparoscopic suturing task under "self-paced" (SP) and "TP" conditions (TP = maximum 2 minutes per knot). Subjective workload was quantified using the Surgical Task Load Index. PFC activation was inferred using optical neuroimaging. Technical skill was assessed using progression scores (au), error scores (mm), leak volumes (mL), and knot tensile strengths (N). TP led to greater perceived workload amongst all residents (mean Surgical Task Load Index score ± SD: PGY1-2: SP = 160.3 ± 24.8 vs TP = 202.1 ± 45.4, P < 0.001; PGY3-4: SP = 123.0 ± 52.0 vs TP = 172.5 ± 43.1, P < 0.01; PGY5: SP = 105.8 ± 55.3 vs TP = 159.1 ± 63.1, P < 0.05). Amongst PGY1-2 and PGY3-4, deterioration in task progression, error scores and knot tensile strength (P < 0.05), and diminished PFC activation was observed under TP. In PGY5, TP resulted in inferior task progression and error scores (P < 0.05), but preservation of knot tensile strength. Furthermore, PGY5 exhibited less attenuation of PFC activation under TP, and greater activation than either PGY1-2 or PGY3-4 under both experimental conditions (P < 0.05). Senior residents cope better with temporal demands and exhibit greater technical performance stability under pressure, possibly due to sustained PFC activation and greater task engagement. Future work should seek to develop training strategies that recruit prefrontal resources, enhance task engagement, and improve performance under pressure.

Achieving Stable Radiation Pressure Acceleration of Heavy Ions via Successive Electron Replenishment from Ionization of a High-Z Material Coating

NASA Astrophysics Data System (ADS)

Shen, X. F.; Qiao, B.; Zhang, H.; Kar, S.; Zhou, C. T.; Chang, H. X.; Borghesi, M.; He, X. T.

2017-05-01

A method to achieve stable radiation pressure acceleration (RPA) of heavy ions from laser-irradiated ultrathin foils is proposed, where a high-Z material coating in front is used. The coated high-Z material, acting as a moving electron repository, continuously replenishes the accelerating heavy ion foil with comoving electrons in the light-sail acceleration stage due to its successive ionization under laser fields with Gaussian temporal profile. As a result, the detrimental effects such as foil deformation and electron loss induced by the Rayleigh-Taylor-like and other instabilities in RPA are significantly offset and suppressed so that stable acceleration of heavy ions are maintained. Particle-in-cell simulations show that a monoenergetic Al13 + beam with peak energy 3.8 GeV and particle number 1 010 (charge >20 nC ) can be obtained at intensity 1 022 W /cm2 .

Efficient and Stable Silicon Microwire Photocathodes with a Nickel Silicide Interlayer for Operation in Strongly Alkaline Solutions

PubMed Central

2018-01-01

Most photoanodes commonly applied in solar fuel research (e.g., of Fe2O3, BiVO4, TiO2, or WO3) are only active and stable in alkaline electrolytes. Silicon (Si)-based photocathodes on the other hand are mainly studied under acidic conditions due to their instability in alkaline electrolytes. Here, we show that the in-diffusion of nickel into a 3D Si structure, upon thermal annealing, yields a thin (sub-100 nm), defect-free nickel silicide (NiSi) layer. This has allowed us to design and fabricate a Si microwire photocathode with a NiSi interlayer between the catalyst and the Si microwires. Upon electrodeposition of the catalyst (here, nickel molybdenum) on top of the NiSi layer, an efficient, Si-based photocathode was obtained that is stable in strongly alkaline solutions (1 M KOH). The best-performing, all-earth-abundant microwire array devices exhibited, under AM 1.5G simulated solar illumination, an ideal regenerative cell efficiency of 10.1%. PMID:29780886

Radiosurgery for Medial Temporal Lobe Epilepsy Resulting from Mesial Temporal Sclerosis.

PubMed

Gianaris, Thomas; Witt, Thomas; Barbaro, Nicholas M

2016-01-01

Medial temporal lobe epilepsy associated with mesial temporal sclerosis (MTS) is perhaps the most well-defined epilepsy syndrome that is responsive to structural interventions such as surgery. Several minimally invasive techniques have arisen that provide additional options for the treatment of MTS while potentially avoiding many of open surgery's associated risks. By evading these risks, they also open up treatment options to patients who otherwise are poor surgical candidates. Radiosurgery is one of the most intensively studied of these alternatives and has found a growing role in the treatment of medial temporal lobe epilepsy. Copyright © 2016 Elsevier Inc. All rights reserved.

Water column distribution of stable isotopes and carbonate properties in the South-eastern Levantine basin (Eastern Mediterranean): Vertical and temporal change

NASA Astrophysics Data System (ADS)

Sisma-Ventura, G.; Yam, R.; Kress, N.; Shemesh, A.

2016-06-01

Water column distributions of the oxygen isotopic composition of sea-water (δ18OSW) and the stable carbon isotope ratio of dissolved inorganic carbon (δ13CDIC), total alkalinity (AT) and the pH (total scale) at 25 °C (25 °CpHTotal) were investigated along the Southeast Mediterranean (SE-Med) shelf and open water, during 2009-2010. While, the vertical profiles of δ18OSW lacked a clear depth signature, those of δ13CDIC were characterized by a structure that reflects the major water masses in the Levantine basin, with noticeable vertical gradients. The δ13CDIC Suess effect of the Levantine water column was estimated from the difference between the average profiles of 1988 and 2009-2010 (Δδ13CDIC). We observed δ13CDIC temporal change, which indicates propagation of anthropogenic CO2 (Cant) to depth of about 700 m. The Modified Atlantic Water (MAW; 0-200 m) and the Levantine Intermediate Water (LIW; 200-400 m) exhibited a depletion rate of - 0.13 ± 0.03 and - 0.11 ± 0.03‰ decade- 1, respectively, representing 50% of the atmospheric change, while the deep water of the Adriatic source (700-1300 m) did not change during this period. A Δδ13CDIC depletion trend was also recognized below 1350 m, corresponding to the Aegean source deep water (EMDWAeg) and therefore associated to the Eastern Mediterranean Transient (EMT) event. Anthropogenic CO2 accumulation rate of 0.38 ± 0.12 mol C m- 2 yr- 1 for the upper 700 m of the SE-Med, over the last 22 yr, was estimated on the basis of mean depth-integrated δ13CDIC Suess effect profile. Our results confirm lower accumulation rate than that of the subtropical North Atlantic, resulting due to the super-saturation with respect to CO2 of the well-stratified Levantine surface water. High pCO2 saturation during summer (+ 150 μatm), in oppose to a small degree of under-saturation in winter (- 30 μatm) was calculated from surface water AT and 25 °CpHTotal data. However, the δ13CDIC depletion trend of the LIW and the

Temporal behaviour of a corner separation in a radial vaned diffuser of a centrifugal compressor operating near surge

NASA Astrophysics Data System (ADS)

Marsan, A.; Trébinjac, I.; Coste, S.; Leroy, G.

2013-12-01

The temporal behaviour of a flow separation in the hub-suction side corner of a transonic diffuser is studied thanks to unsteady numerical simulations based on the phase-lagged approach. The validity of the numerical results is confirmed by comparison with experimental unsteady pressure measurements. An analysis of the instantaneous skin-friction pattern and particles trajectories is presented. It highlights the topology of the separation and its temporal behaviour. The major result is that, despite of a highly time-dependent core flow, the separation is found to be a "fixed unsteady separation" characterized by a fixed location of the main saddle of the separation but an extent of the stall region modulated by the pressure waves induced by the impeller-diffuser interaction.

Effects of Sampling and Spatio/Temporal Granularity in Traffic Monitoring on Anomaly Detectability

NASA Astrophysics Data System (ADS)

Ishibashi, Keisuke; Kawahara, Ryoichi; Mori, Tatsuya; Kondoh, Tsuyoshi; Asano, Shoichiro

We quantitatively evaluate how sampling and spatio/temporal granularity in traffic monitoring affect the detectability of anomalous traffic. Those parameters also affect the monitoring burden, so network operators face a trade-off between the monitoring burden and detectability and need to know which are the optimal paramter values. We derive equations to calculate the false positive ratio and false negative ratio for given values of the sampling rate, granularity, statistics of normal traffic, and volume of anomalies to be detected. Specifically, assuming that the normal traffic has a Gaussian distribution, which is parameterized by its mean and standard deviation, we analyze how sampling and monitoring granularity change these distribution parameters. This analysis is based on observation of the backbone traffic, which exhibits spatially uncorrelated and temporally long-range dependence. Then we derive the equations for detectability. With those equations, we can answer the practical questions that arise in actual network operations: what sampling rate to set to find the given volume of anomaly, or, if the sampling is too high for actual operation, what granularity is optimal to find the anomaly for a given lower limit of sampling rate.

Spatial and temporal variation of diet within a presumed metapopulation of Adelie penguins

USGS Publications Warehouse

Ainley, D.G.; Ballard, G.; Barton, K.J.; Karl, B.J.; Rau, G.H.; Ribic, C.A.; Wilson, P.R.

2003-01-01

We investigated temporal and spatial variability in the diet of chick-provisioning Ade??lie Penguins (Pygoscelis adeliae) breeding at all colonies within one isolated cluster in the southwestern Ross Sea, Antarctica, 1994-2000. We wished to determine if prey quality explained different population growth and emigration rates among colonies. Diet composition was described both by conventional means (stomach samples) and by analysis of stable isotopes in chick tissues (toenails of individuals killed by skuas [Stercorarius maccormicki]). Diets were similar among the four study colonies compared to the disparity apparent among 14 widely spaced sites around the continent. Calorimetry indicated that fish are more energetically valuable than krill, implying that if diet varied by colony, diet quality could attract recruits and help to explain differential rates of colony growth. However, a multiple-regression analysis indicated that diet varied as a function of year, time within the year, and percent of foraging area covered by sea ice, but not by colony location. Stable isotopes revealed similarity of diet at one colony where conventional sampling was not possible. We confirmed that sea ice importantly affects diet composition of this species in neritic waters, and found that (1) quality of summer diet cannot explain different population growth rates among colonies, and (2) stable isotope analysis of chick tissues (toenails) is a useful tool to synoptically describe diet in this species over a large area.

The quiescent H-mode regime for high performance edge localized mode-stable operation in future burning plasmas [The quiescent H-mode regime for high performance ELM-stable operation in future burning plasmas

DOE PAGES

Garofalo, Andrea M.; Burrell, Keith H.; Eldon, David; ...

2015-05-26

For the first time, DIII-D experiments have achieved stationary quiescent H-mode (QH-mode) operation for many energy confinement times at simultaneous ITER-relevant values of beta, confinement, and safety factor, in an ITER similar shape. QH-mode provides excellent energy confinement, even at very low plasma rotation, while operating without edge localized modes (ELMs) and with strong impurity transport via the benign edge harmonic oscillation (EHO). By tailoring the plasma shape to improve the edge stability, the QH-mode operating space has also been extended to densities exceeding 80% of the Greenwald limit, overcoming the long-standing low-density limit of QH-mode operation. In the theory,more » the density range over which the plasma encounters the kink-peeling boundary widens as the plasma cross-section shaping is increased, thus increasing the QH-mode density threshold. Here, the DIII-D results are in excellent agreement with these predictions, and nonlinear MHD analysis of reconstructed QH-mode equilibria shows unstable low n kink-peeling modes growing to a saturated level, consistent with the theoretical picture of the EHO. Furthermore, high density operation in the QH-mode regime has opened a path to a new, previously predicted region of parameter space, named “Super H-mode” because it is characterized by very high pedestals that can be more than a factor of two above the peeling-ballooning stability limit for similar ELMing H-mode discharges at the same density.« less

Coding of odors by temporal binding within a model network of the locust antennal lobe.

PubMed

Patel, Mainak J; Rangan, Aaditya V; Cai, David

2013-01-01

The locust olfactory system interfaces with the external world through antennal receptor neurons (ORNs), which represent odors in a distributed, combinatorial manner. ORN axons bundle together to form the antennal nerve, which relays sensory information centrally to the antennal lobe (AL). Within the AL, an odor generates a dynamically evolving ensemble of active cells, leading to a stimulus-specific temporal progression of neuronal spiking. This experimental observation has led to the hypothesis that an odor is encoded within the AL by a dynamically evolving trajectory of projection neuron (PN) activity that can be decoded piecewise to ascertain odor identity. In order to study information coding within the locust AL, we developed a scaled-down model of the locust AL using Hodgkin-Huxley-type neurons and biologically realistic connectivity parameters and current components. Using our model, we examined correlations in the precise timing of spikes across multiple neurons, and our results suggest an alternative to the dynamic trajectory hypothesis. We propose that the dynamical interplay of fast and slow inhibition within the locust AL induces temporally stable correlations in the spiking activity of an odor-dependent neural subset, giving rise to a temporal binding code that allows rapid stimulus detection by downstream elements.

Predicting heavy episodic drinking using an extended temporal self-regulation theory.

PubMed

Black, Nicola; Mullan, Barbara; Sharpe, Louise

2017-10-01

Alcohol consumption contributes significantly to the global burden from disease and injury, and specific patterns of heavy episodic drinking contribute uniquely to this burden. Temporal self-regulation theory and the dual-process model describe similar theoretical constructs that might predict heavy episodic drinking. The aims of this study were to test the utility of temporal self-regulation theory in predicting heavy episodic drinking, and examine whether the theoretical relationships suggested by the dual-process model significantly extend temporal self-regulation theory. This was a predictive study with 149 Australian adults. Measures were questionnaires (self-report habit index, cues to action scale, purpose-made intention questionnaire, timeline follow-back questionnaire) and executive function tasks (Stroop, Tower of London, operation span). Participants completed measures of theoretical constructs at baseline and reported their alcohol consumption two weeks later. Data were analysed using hierarchical multiple linear regression. Temporal self-regulation theory significantly predicted heavy episodic drinking (R 2 =48.0-54.8%, p<0.001) and the hypothesised extension significantly improved the prediction of heavy episodic drinking frequency (ΔR 2 =4.5%, p=0.001) but not peak consumption (ΔR 2 =1.4%, p=0.181). Intention and behavioural prepotency directly predicted heavy episodic drinking (p<0.01). Planning ability moderated the intention-behaviour relationship and inhibitory control moderated the behavioural prepotency-behaviour relationship (p<0.05). Both temporal self-regulation theory and the extended temporal self-regulation theory provide good prediction of heavy episodic drinking. Intention, behavioural prepotency, planning ability and inhibitory control may be good targets for interventions designed to decrease heavy episodic drinking. Copyright © 2017 Elsevier Ltd. All rights reserved.

Remote Operations of Laser Guide Star Systems: Gemini Observatory.

NASA Astrophysics Data System (ADS)

Oram, Richard J.; Fesquet, Vincent; Wyman, Robert; D'Orgeville, Celine

2011-03-01

The Gemini North telescope, equipped with a 14W laser, has been providing Laser Guide Star Adaptive Optics (LGS AO) regular science queue observations for worldwide astronomers since February 2007. The new 55W laser system for MCAO was installed on the Gemini South telescope in May 2010. In this paper, we comment on how Gemini Observatory developed regular remote operation of the Laser Guide Star Facility and high-power solid-state laser as routine normal operations. Fully remote operation of the LGSF from the Hilo base facility HBF was initially trialed and then optimized and became the standard operating procedure (SOP) for LGS operation in December 2008. From an engineering perspective remote operation demands stable, well characterized and base-lined equipment sets. In the effort to produce consistent, stable and controlled laser parameters (power, wavelength and beam quality) we completed a failure mode effect analysis of the laser system and sub systems that initiated a campaign of hardware upgrades and procedural improvements to the routine maintenance operations. Finally, we provide an overview of normal operation procedures during LGS runs and present a snapshot of data accumulated over several years that describes the overall LGS AO observing efficiency at the Gemini North telescope.

[Duration and temporality].

PubMed

Fouks, L; Guibert, S; Cardon; Montot

1990-01-01

The notion of temporality in living is in perpetual motion between passive temporality and creative conscience. Human existence is not purely immanent, a flow of transcedence continually runs through it. Melancholia is a lose of creativity accompanied by a feeling that time as lived has stopped, time being lived as a new mode of space. Maniac temporality is an improductive and unsociable furious flight toward. The melancholic feeling out of time is crushed by the problematic of alterity, sin and eternity. The maniac lives an imaginary and deceptive problematic. The ambivalent ideal of the schizophrenic is both a return to biological life as well as a fascination by formal thought.

High variability in spatial and temporal size-based trophodynamics of deep-sea fishes from the Mid-Atlantic Ridge elucidated by stable isotopes

NASA Astrophysics Data System (ADS)

Reid, William D. K.; Sweeting, Christopher J.; Wigham, Ben D.; McGill, Rona A. R.; Polunin, Nicholas V. C.

2013-12-01

Demersal fish play an important role in the deep-sea ecosystem by acting as a link to mobile food in the water column, consuming benthic fauna, breaking down large food parcels and dispersing organic matter over large areas. Poor diet resolution from stomach content analysis often impairs the ability to assess differences in inter- and intra-population trophodynamics and therefore understand resource partitioning among deep-sea fishes. Antimora rostrata (predator-scavenger), Coryphaenoides armatus (predator-scavenger), Coryphaenoides brevibarbis (predator) and Halosauropsis macrochir (predator) were collected from 3 stations on the Mid-Atlantic Ridge (MAR) in 2007 and 2009 to investigate trophic ecology using δ13C and δ15N. Variability in lipid-normalised δ13C (δ13Cn) and δ15N was explained by body length in all species but slope and significance of the isotope-length relationships varied both temporally and spatially. δ15N increases with length were observed in A. rostrata at all stations, C. brevibarbis and H. macrochir at one or more stations but were absent in C. armatus. δ13Cn increased with length in A. rostrata but the slope of δ13Cn-length relationships varied spatially and temporally in C. armatus and C. brevibarbis. The co-occurring δ13Cn and δ15N size-based trends in A. rostrata and H. macrochir suggested that size-based trends were a result of increasing trophic position. In C. armatus and C. brevibarbis the isotope-length trends were difficult to distinguish among trophic position increases, shifts in resource use i.e. benthic to pelagic or internal physiology. However, the overall strength, direction and significance of isotope-length trends varied temporally and spatially which suggested varying degrees of overlap in trophic ecology and feeding plasticity among these species.

Temporal Integration of Auditory Information Is Invariant to Temporal Grouping Cues

PubMed

Liu, Andrew S K; Tsunada, Joji; Gold, Joshua I; Cohen, Yale E

2015-01-01

Auditory perception depends on the temporal structure of incoming acoustic stimuli. Here, we examined whether a temporal manipulation that affects the perceptual grouping also affects the time dependence of decisions regarding those stimuli. We designed a novel discrimination task that required human listeners to decide whether a sequence of tone bursts was increasing or decreasing in frequency. We manipulated temporal perceptual-grouping cues by changing the time interval between the tone bursts, which led to listeners hearing the sequences as a single sound for short intervals or discrete sounds for longer intervals. Despite these strong perceptual differences, this manipulation did not affect the efficiency of how auditory information was integrated over time to form a decision. Instead, the grouping manipulation affected subjects' speed-accuracy trade-offs. These results indicate that the temporal dynamics of evidence accumulation for auditory perceptual decisions can be invariant to manipulations that affect the perceptual grouping of the evidence.

Chronic Environmental Stress and the Temporal Course of Depression and Panic Disorder: A Trait-State-Occasion Modeling Approach

PubMed Central

Conway, Christopher C.; Rutter, Lauren A.; Brown, Timothy A.

2015-01-01

Both acute stressful life events and ongoing strains are thought to confer vulnerability to emotional disorders. Unremitting stressful conditions may be particularly pathogenic, but prior research has struggled to delimit chronic versus transient stressful experiences. We aimed to isolate stable stressors—theorized to be indicators of a latent stress proneness trait—and to examine their effects on the temporal course of depression and panic disorder. We recruited 677 patients diagnosed with an emotional disorder and administered interviews for psychopathology and life stress three times over 12-month intervals. Trait-state-occasion modeling revealed that 74% of the variance in life stress was stable over the follow-up period. These stable stressors were associated with a more refractory course of depression and, to a much lesser extent, panic disorder over time. Additionally, neither gender nor participation in cognitive-behavioral therapy affected the persistence of environmental stress over the study timeframe. We discuss implications of these findings for explaining depression recurrence, improving psychological interventions for emotional disorders, and the measurement and evaluation of stress proneness. PMID:26595465

Stable Water Use Efficiency under Climate Change of Three Sympatric Conifer Species at the Alpine Treeline

PubMed Central

Wieser, Gerhard; Oberhuber, Walter; Gruber, Andreas; Leo, Marco; Matyssek, Rainer; Grams, Thorsten Erhard Edgar

2016-01-01

The ability of treeline associated conifers in the Central Alps to cope with recent climate warming and increasing CO2 concentration is still poorly understood. We determined tree ring stable carbon and oxygen isotope ratios of Pinus cembra, Picea abies, and Larix decidua trees from 1975 to 2010. Stable isotope ratios were compared with leaf level gas exchange measurements carried out in situ between 1979 and 2007. Results indicate that tree ring derived intrinsic water-use efficiency (iWUE) of P. cembra, P. abies and L. decidua remained constant during the last 36 years despite climate warming and rising atmospheric CO2. Temporal patterns in Δ13C and Δ18O mirrored leaf level gas exchange assessments, suggesting parallel increases of CO2-fixation and stomatal conductance of treeline conifer species. As at the study site soil water availability was not a limiting factor iWUE remained largely stable throughout the study period. The stability in iWUE was accompanied by an increase in basal area increment (BAI) suggesting that treeline trees benefit from both recent climate warming and CO2 fertilization. Finally, our results suggest that iWUE may not change species composition at treeline in the Austrian Alps due to similar ecophysiological responses to climatic changes of the three sympatric study species. PMID:27375653

Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer

NASA Astrophysics Data System (ADS)

Zhou, Bowen

and reconstruction LES framework. The DRM is a mixed model that consists of subgrid scale (SGS) and resolved subfilter scale (RSFS) components. The RSFS portion is represented by a scale-similarity model that allows for backscatter of energy from the SFS to the mean flow. Compared to conventional closures, the DRM is able to sustain resolved turbulence under moderate stability at coarser resolution (thus saving computational resources). The DRM performs equally well at fine resolution. Under strong stability, the DRM simulates an intermittently turbulent SBL, whereas conventional closures predict false laminar flows. The improved simulation methodology of the SBL has many potential applications in the area of wind energy, numerical weather prediction, pollution modeling and so on. The SBL is first simulated over idealized flat terrain with prescribed forcings and periodic lateral boundaries. A wide range of stability regimes, from weakly to strongly stable conditions, is tested to evaluate model performance. Under strongly stable conditions, intermittency due to mean shear and turbulence interactions is simulated and analyzed. Furthermore, results of the strongly stable SBL are used to improve wind farm siting and nighttime operations. Moving away from the idealized setting, the SBL is simulated over relatively flat terrain at a Kansas site over the Great Plains, where the Cooperative Atmospheric-Surface Exchange Study -- 1999 (CASES-99) took place. The LES obtains realistic initial and lateral boundary conditions from a meso-scale model reanalysis through a grid nesting procedure. Shear-instability induced intermittency observed on the night of Oct 5th during CASES-99 is reproduced to good temporal and magnitude agreement. The LES locates the origin of the shear-instability waves in a shallow upwind valley, and uncovers the intermittency mechanism to be wave breaking over a standing wave (formed over a stagnant cold-air bubble) across the valley. Finally, flow over

Gender differences in temporal relationships between gambling urge and cognitions in treatment-seeking adults.

PubMed

Dunsmuir, Phoebe; Smith, David; Fairweather-Schmidt, A Kate; Riley, Ben; Battersby, Malcolm

2018-04-01

Many gambling-specific CBT programs seek to target either gambling-related urge or cognitions or both. However, little is known of the influence of one symptom type on another across time and whether these differ for men and women help-seeking problem gamblers. The aim of this study was threefold: to determine presence of measurement invariance for urge and cognition measures over time; to investigate the effect of baseline urge on end-of-treatment gambling-related cognitions - and the reciprocal relationship; and, identify whether these pathways differ across gender. Self-reported gambling urge (GUS), and gambling-related cognitions (GRCS) data from treatment-seeking problem gamblers prior to and post treatment (N = 223; 62% men) were analyzed with cross-lagged panel models, moderated by gender. Conceptualization of urge and cognitions were found to be temporally stable. There was no significant association between baseline GUS scores and post-treatment GRCS scores, nor the reverse relationship. Putatively, this infers that coexisting urge and gambling-related cognition components of problem gambling operate independently over time. Analyses revealed gambling urge had a significantly stronger tracking correlation across time for men than women when adjusting for cognition paths. This investigation provides early evidence for tailoring CBT in response to sub-population gambling-related characteristics, demonstrated across men and women. Copyright © 2018 Elsevier B.V. All rights reserved.

Response of leaf stable carbon isotope composition to temporal and spatial variabilities of aridity index on two opposite hillslopes in a native vegetated catchment

NASA Astrophysics Data System (ADS)

Xu, Xiang; Guan, Huade; Skrzypek, Grzegorz; Simmons, Craig T.

2017-10-01

The stable carbon isotope composition (δ13C) has been demonstrated to be a useful indicator of environmental conditions occurring during plant growth. Previous studies suggest that tree leaf δ13C is correlated with mean annual precipitation (MAP) over a broad range of climates with precipitation between 100 and 2000 mm/year. However, this relationship confirmed at the large scale may not be present at the local scale with complex terrain where factors other than precipitation may lead to additional variability in plant water stress. In this study, we investigated δ13C of tree leaves in a native vegetation catchment over a local gradient of hydro-climatic conditions induced by two hillslopes with opposite aspects. Significant seasonal variations, calculated as a difference between the maximum and minimum δ13C values for each tree, were observed for two species, up to 1.9‰ for Eucalyptus (E.) paniculata, and up to 2.7‰ for Acacia (A.) pycnantha on the north-facing slope (NFS). Also the mean δ13C values calculated from all investigated trees of each hillslope were significantly different and leaf δ13C on the NFS was higher by 1.4 ± 0.5‰ than that on the south-facing slope (SFS). These results cannot be explained by the negligible difference in precipitation between the two hillslopes located just 200 m apart. The correlation coefficients between the δ13C of E. tree leaves and the integrated aridity index (AI) were statistically significant for temporal observations on the NFS (R2 0.18-0.44, p-value 0.00-0.06), and spatial observations (R2 = 0.35, p-value 0.05) at the end of the dry season. These results suggest that AI as a measure of plant water stress is better associated with leaf δ13C than precipitation. Therefore, leaf δ13C value can be used as a valuable proxy for plant water stress across the landscape in both time and space.

Temporal separation and self-rating of alertness as indicators of driver fatigue in commercial motor vehicle operators.

PubMed

Belz, Steven M; Robinson, Gary S; Casali, John G

2004-01-01

This on-road field investigation employed, for the first time, a completely automated trigger-based data collection system capable of evaluating driver performance in an extended-duration real-world commercial motor vehicle environment. The study examined the use of self-assessment of fatigue (Karolinska Sleepiness Scale) and temporal separation (minimum time to collision, minimum headway, and mean headway) as indicators of driver fatigue. Without exception, the correlation analyses for both the self-rating of alertness and temporal separation yielded models low in associative ability; neither metric was found to be a valid indicator of driver fatigue. In addition, based upon the data collected for this research, preliminary evidence suggests that driver fatigue onset within a real-world driving environment does not appear to follow the standard progression of events associated with the onset of fatigue within a simulated driving environment. Application of this research includes the development of an on-board driver performance/fatigue monitoring system that could potentially assist drivers in identifying the onset of fatigue.

Tracing amino acid exchange during host-pathogen interaction by combined stable-isotope time-resolved Raman spectral imaging

NASA Astrophysics Data System (ADS)

Naemat, Abida; Elsheikha, Hany M.; Boitor, Radu A.; Notingher, Ioan

2016-02-01

This study investigates the temporal and spatial interchange of the aromatic amino acid phenylalanine (Phe) between human retinal pigment epithelial cell line (ARPE-19) and tachyzoites of the apicomplexan protozoan parasite Toxoplasma gondii (T. gondii). Stable isotope labelling by amino acids in cell culture (SILAC) is combined with Raman micro-spectroscopy to selectively monitor the incorporation of deuterium-labelled Phe into proteins in individual live tachyzoites. Our results show a very rapid uptake of L-Phe(D8) by the intracellular growing parasite. T. gondii tachyzoites are capable of extracting L-Phe(D8) from host cells as soon as it invades the cell. L-Phe(D8) from the host cell completely replaces the L-Phe within T. gondii tachyzoites 7-9 hours after infection. A quantitative model based on Raman spectra allowed an estimation of the exchange rate of Phe as 0.5-1.6 × 104 molecules/s. On the other hand, extracellular tachyzoites were not able to consume L-Phe(D8) after 24 hours of infection. These findings further our understanding of the amino acid trafficking between host cells and this strictly intracellular parasite. In particular, this study highlights new aspects of the metabolism of amino acid Phe operative during the interaction between T. gondii and its host cell.

Toward a clinic of temporality?

PubMed

Rivasseau Jonveaux, Thérèse; Batt, Martine; Trognon, Alain

2017-12-01

The discovery of time cells has expanded our knowledge in the field of spatial and temporal information coding and the key role of the hippocampus. The internal clock model complemented with the attentional gate model allows a more in-depth understanding of the perception of time. The motor representation of duration is ensured by the basal ganglia, while the cerebellum synchronizes short duration for the movement. The right prefrontal cortex seemingly intervenes in the handling of temporal information in working memory. The temporal lobe ensures the comparison of durations, especially the right lobe for the reference durations and the medial lobe for the reproduction of durations in episodic memory. During normal aging, the hypothesis of slowing of the temporal processor is evoked when noting the perception of the acceleration of the passage of time that seemingly occurs with advancing age. The various studies pertaining specifically to time cognition, albeit heterogeneous in terms of methodology, attest to the wide-ranging disturbances of this cognitive field during the course of numerous disorders, whether psychiatric - depression and schizophrenia notably - or neurological. Hence, perturbations in temporality are observed in focal brain lesions and in subcortical disorders, such as Parkinson's disease or Huntington's chorea. Alzheimer's disease represents a particularly fertile field of exploration with regard to time cognition and temporality. The objectified deconstruction of temporal experience provides insights into the very processes of temporality and their nature: episodic, semantic and procedural. In addition to exploration based on elementary stimuli, one should also consider the time lived, i.e. that of the subject, to better understand cognition as it relates to time. While the temporal dimension permeates the whole cognitive field, it remains largely neglected: integration of a genuine time cognition and temporality clinic in daily practice remains

Upper trophic structure in the Atlantic Patagonian shelf break as inferred from stable isotope analysis

NASA Astrophysics Data System (ADS)

Zhu, Guoping; Zhang, Haiting; Yang, Yang; Wang, Shaoqin; Wei, Lian; Yang, Qingyuan

2017-09-01

The Patagonian Shelf is a very productive region with different ecosystem structures. A long history of fishing in the Southwestern Atlantic Ocean combined with a complex hydrographic structure, with a permanent front over the shelf-break and different coastal frontal regions, and a wide non-frontal area in between have made the food web in this area more complex and have resulted in changes to the spatial-temporal scale. Stable isotopes of carbon and nitrogen were used to determine the trophic structure of the Patagonian shelf break which was previously poorly understood. The results indicated that the average δ15N value of pelagic guild (Illex argentinus) was remarkable lower than those of the other guilds. The δ13C values of almost all species ranged from -17‰ to -18‰, but Stromateus brasiliensis had a significant lower δ13C value. Compared with the southern Patagonian shelf, short food chain length also occurred. The impact of complex oceanographic structures has resulted in food web structure change to the temporal-spatial scale on the Patagonian shelf. The Patagonian shelf break can be considered as a separated ecosystem structure with lower δ15N values.

Nonlesional atypical mesial temporal epilepsy

PubMed Central

Alexopoulos, Andreas V.; Busch, Robyn M.; Wehner, Tim; Nair, Dileep; Bingaman, William E.; Najm, Imad M.

2013-01-01

Objective: Misleading manifestations of common epilepsy syndromes might account for some epilepsy surgery failures, thus we sought to characterize patients with difficult to diagnose (atypical) mesial temporal lobe epilepsy (mTLE). Methods: We retrospectively reviewed our surgical database over 12 years to identify patients who underwent a standard anterior temporal lobectomy after undergoing intracranial EEG (ICEEG) evaluation with a combination of depth and subdural electrodes. We carefully studied electroclinical manifestations, neuroimaging data, neuropsychological findings, and indications for ICEEG. Results: Of 835 patients who underwent anterior temporal lobectomy, 55 were investigated with ICEEG. Ten of these had atypical mTLE features and were not considered to have mTLE preoperatively. All of them had Engel class I outcome for 3 to 7 years (median 3.85). Five reported uncommon auras, and 3 had no auras. Scalp-EEG and nuclear imaging studies failed to provide adequate localization. None had MRI evidence of hippocampal sclerosis. However, ICEEG demonstrated exclusive mesial temporal seizure onset in all patients. Clues suggesting the possibility of mTLE were typical auras when present, anterior temporal epileptiform discharges or ictal patterns, small hippocampi, asymmetrical or ipsilateral temporal hypometabolism on PET, anterior temporal hyperperfusion on ictal SPECT, and asymmetry of memory scores. Histopathology revealed hippocampal sclerosis in 6 patients and gliosis in 2. Conclusions: Atypical electroclinical presentation may be deceptive in some patients with mTLE. We emphasize the importance of searching for typical mTLE features to guide ICEEG study of mesial temporal structures in such patients, who may otherwise mistakenly undergo extramesial temporal resections or be denied surgery. PMID:24174582

Producing air-stable monolayers of phosphorene and their defect engineering

PubMed Central

Pei, Jiajie; Gai, Xin; Yang, Jiong; Wang, Xibin; Yu, Zongfu; Choi, Duk-Yong; Luther-Davies, Barry; Lu, Yuerui

2016-01-01

It has been a long-standing challenge to produce air-stable few- or monolayer samples of phosphorene because thin phosphorene films degrade rapidly in ambient conditions. Here we demonstrate a new highly controllable method for fabricating high quality, air-stable phosphorene films with a designated number of layers ranging from a few down to monolayer. Our approach involves the use of oxygen plasma dry etching to thin down thick-exfoliated phosphorene flakes, layer by layer with atomic precision. Moreover, in a stabilized phosphorene monolayer, we were able to precisely engineer defects for the first time, which led to efficient emission of photons at new frequencies in the near infrared at room temperature. In addition, we demonstrate the use of an electrostatic gate to tune the photon emission from the defects in a monolayer phosphorene. This could lead to new electronic and optoelectronic devices, such as electrically tunable, broadband near infrared lighting devices operating at room temperature. PMID:26794866

High-speed highly temperature stable 980 nm VCSELs operating at 25 Gb/s at up to 85 °C for short reach optical interconnects

NASA Astrophysics Data System (ADS)

Mutig, Alex; Lott, James A.; Blokhin, Sergey A.; Moser, Philip; Wolf, Philip; Hofmann, Werner; Nadtochiy, Alexey M.; Bimberg, Dieter

2011-03-01

The progressive penetration of optical communication links into traditional copper interconnect markets greatly expands the applications of vertical cavity surface emitting lasers (VCSELs) for the next-generation of board-to-board, moduleto- module, chip-to-chip, and on-chip optical interconnects. Stability of the VCSEL parameters at high temperatures is indispensable for such applications, since these lasers typically reside directly on or near integrated circuit chips. Here we present 980 nm oxide-confined VCSELs operating error-free at bit rates up to 25 Gbit/s at temperatures as high as 85 °C without adjustment of the drive current and peak-to-peak modulation voltage. The driver design is therefore simplified and the power consumption of the driver electronics is lowered, reducing the production and operational costs. Small and large signal modulation experiments at various temperatures from 20 up to 85 °C for lasers with different oxide aperture diameters are presented in order to analyze the physical processes controlling the performance of the VCSELs. Temperature insensitive maximum -3 dB bandwidths of around 13-15 GHz for VCSELs with aperture diameters of 10 μm and corresponding parasitic cut-off frequencies exceeding 22 GHz are observed. Presented results demonstrate the suitability of our VCSELs for practical high speed and high temperature stable short-reach optical links.

Steady-state inductive spheromak operation

DOEpatents

Janos, Alan C.; Jardin, Stephen C.; Yamada, Masaaki

1987-01-01

The inductively formed spheromak plasma can be maintained in a highly stable and controlled fashion. Steady-state operation is obtained by forming the plasma in the linked mode, then oscillating the poloidal and toroidal fields such that they have different phases. Preferably, the poloidal and magnetic fields are 90.degree. out of phase.

Temporal Control over Transient Chemical Systems using Structurally Diverse Chemical Fuels.

PubMed

Chen, Jack L-Y; Maiti, Subhabrata; Fortunati, Ilaria; Ferrante, Camilla; Prins, Leonard J

2017-08-25

The next generation of adaptive, intelligent chemical systems will rely on a continuous supply of energy to maintain the functional state. Such systems will require chemical methodology that provides precise control over the energy dissipation process, and thus, the lifetime of the transiently activated function. This manuscript reports on the use of structurally diverse chemical fuels to control the lifetime of two different systems under dissipative conditions: transient signal generation and the transient formation of self-assembled aggregates. The energy stored in the fuels is dissipated at different rates by an enzyme, which installs a dependence of the lifetime of the active system on the chemical structure of the fuel. In the case of transient signal generation, it is shown that different chemical fuels can be used to generate a vast range of signal profiles, allowing temporal control over two orders of magnitude. Regarding self-assembly under dissipative conditions, the ability to control the lifetime using different fuels turns out to be particularly important as stable aggregates are formed only at well-defined surfactant/fuel ratios, meaning that temporal control cannot be achieved by simply changing the fuel concentration. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Temporal Order Judgment in Dyslexia--Task Difficulty or Temporal Processing Deficiency?

ERIC Educational Resources Information Center

Skottun, Bernt C.; Skoyles, John R.

2010-01-01

Dyslexia has been widely held to be associated with deficient temporal processing. It is, however, not established that the slower visual processing of dyslexic readers is not a secondary effect of task difficulty. To illustrate this we re-analyze data from Liddle et al. (2009) who studied temporal order judgment in dyslexia and plotted the…

Safety of stable isotope use.

PubMed

Koletzko, B; Sauerwald, T; Demmelmair, H

1997-08-01

The increased employment of stable isotope tracers for diagnostic and research purposes frequently raises questions on potential risks associated with their use, which is of particular importance in the paediatric age group. Biological effects and the potential of adverse events has been evaluated in a large number of animal and, in part, also human studies. Possible differences in physical, chemical and biochemical behaviour resulting in kinetic and thermodynamic isotope effects between stable isotopes of the same element are related to the relative differences in atomic weight. Deuterium (2H), which differs markedly in mass from the predominant hydrogen isotope 1H, may induce serious side-effects at high concentrations in body fluids. The threshold dose for the occurrence of side-effects lies well above the usual tracer dosages for clinical use. In contrast to deuterium, heavier stable isotopes such as 13C, 15N or 18O that differ relatively little in mass from the predominant isotopes such as 12C, does not show any adverse biological effects even at highest enrichments. The doses of stable isotope tracer substances that are used for clinical diagnostic and research purposes appear safe and without any adverse effects. Stable isotope tracers should only be used in children if the trace is safe at the doses applied, and tracer is chemically pure and stable. In the case of intravenous application, the tracer preparation must also be sterile and pyrogen free.

Reassessing the stable isotope composition assigned to methane flux from natural wetlands in isotope-constrained budgets

NASA Astrophysics Data System (ADS)

Hornibrook, Edward; Maxfield, Peter; Gauci, Vincent; Stott, Andrew

2013-04-01

Stable isotope ratios in CH4 preserve information about its origin and history, and are commonly used to constrain global CH4 budgets. Wetlands are key contributors to the atmospheric burden of CH4 and typically are assigned a stable carbon isotope composition of ~-60 permil in isotope-weighted stable isotope models despite the considerable range of δ13C(CH4) values (~ -100 to -40 permil) known to occur in these diverse ecosystems. Kinetic isotope effects (KIEs) associated with the metabolism of CH4-producing microorganisms generate much of the natural variation but highly negative and positive δ13C(CH4) values generally result from secondary processes (e.g., diffusive transport or oxidation by soil methanotrophs). Despite these complexities, consistent patterns exist in the isotope composition of wetland CH4 that can be linked conclusively to trophic status and consequently, natural succession or human perturbations that impact nutrient levels. Another challenge for accurate representation of wetlands in carbon cycle models is parameterisation of sporadic CH4 emission events. Abrupt release of large volumes of CH4-rich bubbles in short periods of time can account for a significant proportion of the annual CH4 flux from a wetland but such events are difficult to detect using conventional methods. New infrared spectroscopy techniques capable of high temporal resolution measurements of CH4 concentration and stable isotope composition can readily quantify short-lived CH4 pulses. Moreover, the isotope data can be used conclusively to determine shifts in the mode of CH4 transport and provide the potential to link initiation of abrupt emission events to forcing by internal or external factors.

Achieving Stable Radiation Pressure Acceleration of Heavy Ions via Successive Electron Replenishment from Ionization of a High-Z Material Coating.

PubMed

Shen, X F; Qiao, B; Zhang, H; Kar, S; Zhou, C T; Chang, H X; Borghesi, M; He, X T

2017-05-19

A method to achieve stable radiation pressure acceleration (RPA) of heavy ions from laser-irradiated ultrathin foils is proposed, where a high-Z material coating in front is used. The coated high-Z material, acting as a moving electron repository, continuously replenishes the accelerating heavy ion foil with comoving electrons in the light-sail acceleration stage due to its successive ionization under laser fields with Gaussian temporal profile. As a result, the detrimental effects such as foil deformation and electron loss induced by the Rayleigh-Taylor-like and other instabilities in RPA are significantly offset and suppressed so that stable acceleration of heavy ions are maintained. Particle-in-cell simulations show that a monoenergetic Al^{13+} beam with peak energy 3.8 GeV and particle number 10^{10} (charge >20  nC) can be obtained at intensity 10^{22}  W/cm^{2}.

Robot Control Based On Spatial-Operator Algebra

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo; Kreutz, Kenneth K.; Jain, Abhinandan

1992-01-01

Method for mathematical modeling and control of robotic manipulators based on spatial-operator algebra providing concise representation and simple, high-level theoretical frame-work for solution of kinematical and dynamical problems involving complicated temporal and spatial relationships. Recursive algorithms derived immediately from abstract spatial-operator expressions by inspection. Transition from abstract formulation through abstract solution to detailed implementation of specific algorithms to compute solution greatly simplified. Complicated dynamical problems like two cooperating robot arms solved more easily.

Influence of horse stable environment on human airways.

PubMed

Elfman, Lena; Riihimäki, Miia; Pringle, John; Wålinder, Robert

2009-05-25

Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. The horse stable environment and stable-workers (n = 13) in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-beta-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. Biomarkers involved in the development of airway diseases have been studied in relation to environmental exposure levels in equine stables. Respirable dust and 1

Highly air stable passivation of graphene based field effect devices.

PubMed

Sagade, Abhay A; Neumaier, Daniel; Schall, Daniel; Otto, Martin; Pesquera, Amaia; Centeno, Alba; Elorza, Amaia Zurutuza; Kurz, Heinrich

2015-02-28

The sensitivity of graphene based devices to surface adsorbates and charge traps at the graphene/dielectric interface requires proper device passivation in order to operate them reproducibly under ambient conditions. Here we report on the use of atomic layer deposited aluminum oxide as passivation layer on graphene field effect devices (GFETs). We show that successful passivation produce hysteresis free DC characteristics, low doping level GFETs stable over weeks though operated and stored in ambient atmosphere. This is achieved by selecting proper seed layer prior to deposition of encapsulation layer. The passivated devices are also demonstrated to be robust towards the exposure to chemicals and heat treatments, typically used during device fabrication. Additionally, the passivation of high stability and reproducible characteristics is also shown for functional devices like integrated graphene based inverters.

Heavy metal-induced stress in rice crops detected using multi-temporal Sentinel-2 satellite images.

PubMed

Liu, Meiling; Wang, Tiejun; Skidmore, Andrew K; Liu, Xiangnan

2018-05-05

Regional-level information on heavy metal pollution in agro-ecosystems is essential for food security because excessive levels of heavy metals in crops may pose risks to humans. However, collecting this information over large areas is inherently costly. This paper investigates the possibility of applying multi-temporal Sentinel-2 satellite images to detect heavy metal-induced stress (i.e., Cd stress) in rice crops in four study areas in Zhuzhou City, Hunan Province, China. For this purpose, we compared seven Sentinel-2 images acquired in 2016 and 2017 with in situ measured hyper-spectral data, chlorophyll content, rice leaf area index, and heavy metal concentrations in soil collected from 2014 to 2017. Vegetation indices (VIs) related to red edge bands were referred to as the sensitive indicators for screening stressed rice from unstressed rice. The coefficients of spatio-temporal variation (CSTV) derived from the VIs allowed us to discriminate crops exposed to pollution from heavy metals as well as environmental stressors. The results indicate that (i) the red edge chlorophyll index, the red edge position index, and the normalized difference red edge 2 index derived from multi-temporal Sentinel-2 images were good indicators for screening stressed rice from unstressed rice; (ii) Rice under Cd stress remained stable with lower CSTV values of VIs overall growth stages in the experimental region, whereas rice under other stressors (i.e., pests and disease) showed abrupt changes at some growth stages and presented "hot spots" with greater CSTV values; and (iii) the proposed spatio-temporal anomaly detection method was successful at detecting rice under Cd stress; and CSTVs of rice VIs stabilized regardless of whether they were applied to consecutive growth stages or to two different crop years. This study suggests that regional heavy metal stress may be accurately detected using multi-temporal Sentinel-2 images, using VIs sensitive to the spatio-temporal

Spatio-temporal activity of lightnings over Greece

NASA Astrophysics Data System (ADS)

Nastos, P. T.; Matsangouras, I. T.; Chronis, T. G.

2012-04-01

Extreme precipitation events are always associated with convective weather conditions driving to intense lightning activity: Cloud to Ground (CG), Ground to Cloud (GC) and Cloud to Cloud (CC). Thus, the study of lightnings, which typically occur during thunderstorms, gives evidence of the spatio-temporal variability of intense precipitation. Lightning is a natural phenomenon in the atmosphere, being a major cause of storm related with deaths and main trigger of forest fires during dry season. Lightning affects the many electrochemical systems of the body causing nerve damage, memory loss, personality change, and emotional problems. Besides, among the various nitrogen oxides sources, the contribution from lightning likely represents the largest uncertainty. An operational lightning detection network (LDN) has been established since 2007 by HNMS, consisting of eight time-of-arrival sensors (TOA), spatially distributed across Greek territory. In this study, the spatial and temporal variability of recorded lightnings (CG, GC and CC) are analyzed over Greece, during the period from January 14, 2008 to December 31, 2009, for the first time. The data for retrieving the location and time-of-occurrence of lightning were acquired from Hellenic National Meteorological Service (HNMS). In addition to the analysis of spatio-temporal activity over Greece, the HNMS-LDN characteristics are also presented. The results of the performed analysis reveal the specific geographical sub-regions associated with lightnings incidence. Lightning activity occurs mainly during the autumn season, followed by summer and spring. Higher frequencies of flashes appear over Ionian and Aegean Sea than over land during winter period against continental mountainous regions during summer period.

Stable configurations in social networks

NASA Astrophysics Data System (ADS)

Bronski, Jared C.; DeVille, Lee; Ferguson, Timothy; Livesay, Michael

2018-06-01

We present and analyze a model of opinion formation on an arbitrary network whose dynamics comes from a global energy function. We study the global and local minimizers of this energy, which we call stable opinion configurations, and describe the global minimizers under certain assumptions on the friendship graph. We show a surprising result that the number of stable configurations is not necessarily monotone in the strength of connection in the social network, i.e. the model sometimes supports more stable configurations when the interpersonal connections are made stronger.

Stable Spheromaks with Profile Control

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

Fowler, T K; Jayakumar, R

A spheromak equilibrium with zero edge current is shown to be stable to both ideal MHD and tearing modes that normally produce Taylor relaxation in gun-injected spheromaks. This stable equilibrium differs from the stable Taylor state in that the current density j falls to zero at the wall. Estimates indicate that this current profile could be sustained by non-inductive current drive at acceptable power levels. Stability is determined using the NIMROD code for linear stability analysis. Non-linear NIMROD calculations with non-inductive current drive could point the way to improved fusion reactors.

On the Assessment of Global Terrestrial Reference Frame Temporal Variations

NASA Astrophysics Data System (ADS)

Ampatzidis, Dimitrios; Koenig, Rolf; Zhu, Shengyuan

2015-04-01

Global Terrestrial Reference Frames (GTRFs) as the International Terrestrial Reference Frame (ITRF) provide reliable 4-D position information (3-D coordinates and their evolution through time). The given 3-D velocities play a significant role in precise position acquisition and are estimated from long term coordinate time series from the space-geodetic techniques DORIS, GNSS, SLR, and VLBI. GTRFs temporal evolution is directly connected with their internal stability: The more intense and inhomogeneous velocity field, the less stable TRF is derived. The assessment of the quality of the GTRF is mainly realized by comparing it to each individual technique's reference frame. E.g the comparison of GTRFs to SLR-only based TRF gives the sense of the ITRF stability with respect to the Geocenter and scale and their associated rates respectively. In addition, the comparison of ITRF to the VLBI-only based TRF can be used for the scale validation. However, till now there is not any specified methodology for the total assessment (in terms of origin, orientation and scale respectively) of the temporal evolution and GTRFs associated accuracy. We present a new alternative diagnostic tool for the assessment of GTRFs temporal evolution based on the well-known time-dependent Helmert type transformation formula (three shifts, three rotations and scale rates respectively). The advantage of the new methodology relies on the fact that it uses the full velocity field of the TRF and therefore all points not just the ones common to different techniques. It also examines simultaneously rates of origin, orientation and scale. The methodology is presented and implemented to the two existing GTRFs on the market (ITRF and DTRF which is computed from DGFI) , the results are discussed. The results also allow to compare directly each GTRF dynamic behavior. Furthermore, the correlations of the estimated parameters can also provide useful information to the proposed GTRFs assessment scheme.

Stable CW Single Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

NASA Technical Reports Server (NTRS)

Duerksen, Gary L.; Krainak, Michael A.

1999-01-01

Previously, single-frequency semiconductor laser operation using fiber Bragg gratings has been achieved by tWo methods: 1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element'; 2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback'. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback.

Stable CW Single-Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

NASA Technical Reports Server (NTRS)

Duerksen, Gary L.; Krainak, Michael A.

1998-01-01

Previously, single-frequency semiconductor laser operation using fiber Bragg gratings (FBG) has been achieved by two methods: (1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element; (2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback.

Harmonic regression based multi-temporal cloud filtering algorithm for Landsat 8

NASA Astrophysics Data System (ADS)

Joshi, P.

2015-12-01

Landsat data archive though rich is seen to have missing dates and periods owing to the weather irregularities and inconsistent coverage. The satellite images are further subject to cloud cover effects resulting in erroneous analysis and observations of ground features. In earlier studies the change detection algorithm using statistical control charts on harmonic residuals of multi-temporal Landsat 5 data have been shown to detect few prominent remnant clouds [Brooks, Evan B., et al, 2014]. So, in this work we build on this harmonic regression approach to detect and filter clouds using a multi-temporal series of Landsat 8 images. Firstly, we compute the harmonic coefficients using the fitting models on annual training data. This time series of residuals is further subjected to Shewhart X-bar control charts which signal the deviations of cloud points from the fitted multi-temporal fourier curve. For the process with standard deviation σ we found the second and third order harmonic regression with a x-bar chart control limit [Lσ] ranging between [0.5σ < Lσ < σ] as most efficient in detecting clouds. By implementing second order harmonic regression with successive x-bar chart control limits of L and 0.5 L on the NDVI, NDSI and haze optimized transformation (HOT), and utilizing the seasonal physical properties of these parameters, we have designed a novel multi-temporal algorithm for filtering clouds from Landsat 8 images. The method is applied to Virginia and Alabama in Landsat8 UTM zones 17 and 16 respectively. Our algorithm efficiently filters all types of cloud cover with an overall accuracy greater than 90%. As a result of the multi-temporal operation and the ability to recreate the multi-temporal database of images using only the coefficients of the fourier regression, our algorithm is largely storage and time efficient. The results show a good potential for this multi-temporal approach for cloud detection as a timely and targeted solution for the Landsat 8

On the hyperbolic nature of the equations of alluvial river hydraulics and the equivalence of stable and energy dissipating shocks

NASA Astrophysics Data System (ADS)

Zanraea, D. D. L.; Needham, D. J.

The depth-averaged hydraulic equations augmented with a suitable bed-load sediment transport function form a closed system which governs the one-dimensional flow in an alluvial river or channel. In this paper, it is shown that this system is hyperbolic and yields three families of shock-wave solutions. These are determined to be temporally stable in restricted regions of the (H, F0)-plane, via the Lax shock inequalities. Further, it is demonstrated that this criterion is equivalent to the energy dissipation criterion developed by Needham and Hey (1991).

Using a virtual reality temporal bone simulator to assess otolaryngology trainees.

PubMed

Zirkle, Molly; Roberson, David W; Leuwer, Rudolf; Dubrowski, Adam

2007-02-01

The objective of this study is to determine the feasibility of computerized evaluation of resident performance using hand motion analysis on a virtual reality temporal bone (VR TB) simulator. We hypothesized that both computerized analysis and expert ratings would discriminate the performance of novices from experienced trainees. We also hypothesized that performance on the virtual reality temporal bone simulator (VR TB) would differentiate based on previous drilling experience. The authors conducted a randomized, blind assessment study. Nineteen volunteers from the Otolaryngology-Head and Neck Surgery training program at the University of Toronto drilled both a cadaveric TB and a simulated VR TB. Expert reviewers were asked to assess operative readiness of the trainee based on a blind video review of their performance. Computerized hand motion analysis of each participant's performance was conducted. Expert raters were able to discriminate novices from experienced trainees (P < .05) on cadaveric temporal bones, and there was a trend toward discrimination on VR TB performance. Hand motion analysis showed that experienced trainees had better movement economy than novices (P < .05) on the VR TB. Performance, as measured by hand motion analysis on the VR TB simulator, reflects trainees' previous drilling experience. This study suggests that otolaryngology trainees could accomplish initial temporal bone training on a VR TB simulator, which can provide feedback to the trainee, and may reduce the need for constant faculty supervision and evaluation.

Phenomenology of spectrally and temporally resolved infrared emissions from bomb detonations

NASA Astrophysics Data System (ADS)

Gross, Kevin; Dills, Anthony; Tuttle, Ron; Perram, Glen

2002-10-01

The remote sensing of infrared signatures from exothermic reactions during military operations, including missile launches, muzzle flashes, and bomb detonations has been studied using fast FTIR techniques. Battle space characterization includes the ability to classify the munitions type, size, and other characteristics. One possible approach to munitions classification is to understand the spectral and temporal signatures from explosive ordinance. To investigate this possibility, experimental data has been collected remotely from ground-based sensors, processed, and analyzed for several conventional munitions. Field observations of 56 detonation events included a set of aircraft delivered ordnance and a series of static ground detonations for a variety of bomb sizes, types and environmental conditions. The emission is well represented by a gray body with continuously decreasing temperature and characteristic decay times of 1-4 s, providing only limited variability with detonation conditions. However, the fireball size times the emissivity as a function of time can be determined from the spectra without imaging and provides a more sensitive signature. The degree of temporal overlap as a function of frequency for a pair of detonation events provides a very sensitive discriminator for explosion conditions. The temporal overlap decreases with increasing emission frequency for all the observed events, indicating more information content at higher frequencies. Finally, the temporal nature of the emissions has been analyzed, providing a significant reduction in the dimensionality of the data.

Stable, high-order computation of impedance-impedance operators for three-dimensional layered medium simulations.

PubMed

Nicholls, David P

2018-04-01

The faithful modelling of the propagation of linear waves in a layered, periodic structure is of paramount importance in many branches of the applied sciences. In this paper, we present a novel numerical algorithm for the simulation of such problems which is free of the artificial singularities present in related approaches. We advocate for a surface integral formulation which is phrased in terms of impedance-impedance operators that are immune to the Dirichlet eigenvalues which plague the Dirichlet-Neumann operators that appear in classical formulations. We demonstrate a high-order spectral algorithm to simulate these latter operators based upon a high-order perturbation of surfaces methodology which is rapid, robust and highly accurate. We demonstrate the validity and utility of our approach with a sequence of numerical simulations.

Stable, high-order computation of impedance-impedance operators for three-dimensional layered medium simulations

NASA Astrophysics Data System (ADS)

Nicholls, David P.

2018-04-01

The faithful modelling of the propagation of linear waves in a layered, periodic structure is of paramount importance in many branches of the applied sciences. In this paper, we present a novel numerical algorithm for the simulation of such problems which is free of the artificial singularities present in related approaches. We advocate for a surface integral formulation which is phrased in terms of impedance-impedance operators that are immune to the Dirichlet eigenvalues which plague the Dirichlet-Neumann operators that appear in classical formulations. We demonstrate a high-order spectral algorithm to simulate these latter operators based upon a high-order perturbation of surfaces methodology which is rapid, robust and highly accurate. We demonstrate the validity and utility of our approach with a sequence of numerical simulations.

The time to remember: Temporal compression and duration judgements in memory for real-life events.

PubMed

Jeunehomme, Olivier; D'Argembeau, Arnaud

2018-05-01

Recent studies suggest that the continuous flow of information that constitutes daily life events is temporally compressed in episodic memory, yet the characteristics and determinants of this compression mechanism remain unclear. This study examined this question using an experimental paradigm incorporating wearable camera technology. Participants experienced a series of real-life events and were later asked to mentally replay various event sequences that were cued by pictures taken during the original events. Estimates of temporal compression (the ratio of the time needed to mentally re-experience an event to the actual event duration) showed that events were replayed, on average, about eight times faster than the original experiences. This compression mechanism seemed to operate by representing events as a succession of moments or slices of prior experience separated by temporal discontinuities. Importantly, however, rates of temporal compression were not constant and were lower for events involving goal-directed actions. The results also showed that the perceived duration of events increased with the density of recalled moments of prior experience. Taken together, these data extend our understanding of the mechanisms underlying the temporal compression and perceived duration of real-life events in episodic memory.

Spatio-temporal Dynamics of Referential and Inferential Naming: Different Brain and Cognitive Operations to Lexical Selection.

PubMed

Fargier, Raphaël; Laganaro, Marina

2017-03-01

Picture naming tasks are largely used to elicit the production of specific words and sentences in psycholinguistic and neuroimaging research. However, the generation of lexical concepts from a visual input is clearly not the exclusive way speech production is triggered. In inferential speech encoding, the concept is not provided from a visual input, but is elaborated though semantic and/or episodic associations. It is therefore likely that the cognitive operations leading to lexical selection and word encoding are different in inferential and referential expressive language. In particular, in picture naming lexical selection might ensue from a simple association between a perceptual visual representation and a word with minimal semantic processes, whereas richer semantic associations are involved in lexical retrieval in inferential situations. Here we address this hypothesis by analyzing ERP correlates during word production in a referential and an inferential task. The participants produced the same words elicited from pictures or from short written definitions. The two tasks displayed similar electrophysiological patterns only in the time-period preceding the verbal response. In the stimulus-locked ERPs waveform amplitudes and periods of stable global electrophysiological patterns differed across tasks after the P100 component and until 400-500 ms, suggesting the involvement of different, task-specific neural networks. Based on the analysis of the time-windows affected by specific semantic and lexical variables in each task, we conclude that lexical selection is underpinned by a different set of conceptual and brain processes, with semantic processes clearly preceding word retrieval in naming from definition whereas the semantic information is enriched in parallel with word retrieval in picture naming.

Spatial-temporal and cancer risk assessment of selected hazardous air pollutants in Seattle.

PubMed

Wu, Chang-fu; Liu, L-J Sally; Cullen, Alison; Westberg, Hal; Williamson, John

2011-01-01

In the Seattle Air Toxics Monitoring Pilot Program, we measured 15 hazardous air pollutants (HAPs) at 6 sites for more than a year between 2000 and 2002. Spatial-temporal variations were evaluated with random-effects models and principal component analyses. The potential health risks were further estimated based on the monitored data, with the incorporation of the bootstrapping technique for the uncertainty analysis. It is found that the temporal variability was generally higher than the spatial variability for most air toxics. The highest temporal variability was observed for tetrachloroethylene (70% temporal vs. 34% spatial variability). Nevertheless, most air toxics still exhibited significant spatial variations, even after accounting for the temporal effects. These results suggest that it would require operating multiple air toxics monitoring sites over a significant period of time with proper monitoring frequency to better evaluate population exposure to HAPs. The median values of the estimated inhalation cancer risks ranged between 4.3 × 10⁻⁵ and 6.0 × 10⁻⁵, with the 5th and 95th percentile levels exceeding the 1 in a million level. VOCs as a whole contributed over 80% of the risk among the HAPs measured and arsenic contributed most substantially to the overall risk associated with metals. Copyright © 2010 Elsevier Ltd. All rights reserved.

The Spatial and Temporal Transcriptomic Landscapes of Ginseng, Panax ginseng C. A. Meyer.

PubMed

Wang, Kangyu; Jiang, Shicui; Sun, Chunyu; Lin, Yanping; Yin, Rui; Wang, Yi; Zhang, Meiping

2015-12-11

Ginseng, including Asian ginseng (Panax ginseng C. A. Meyer) and American ginseng (P. quinquefolius L.), is one of the most important medicinal herbs in Asia and North America, but significantly understudied. This study sequenced and characterized the transcriptomes and expression profiles of genes expressed in 14 tissues and four different aged roots of Asian ginseng. A total of 265.2 million 100-bp clean reads were generated using the high-throughput sequencing platform HiSeq 2000, representing >8.3x of the 3.2-Gb ginseng genome. From the sequences, 248,993 unigenes were assembled for whole plant, 61,912-113,456 unigenes for each tissue and 54,444-65,412 unigenes for different year-old roots. We comprehensively analyzed the unigene sets and gene expression profiles. We found that the number of genes allocated to each functional category is stable across tissues or developmental stages, while the expression profiles of different genes of a gene family or involved in ginsenoside biosynthesis dramatically diversified spatially and temporally. These results provide an overall insight into the spatial and temporal transcriptome dynamics and landscapes of Asian ginseng, and comprehensive resources for advanced research and breeding of ginseng and related species.

Spatio-Temporal Fluctuations of the Earthquake Magnitude Distribution: Robust Estimation and Predictive Power

NASA Astrophysics Data System (ADS)

Olsen, S.; Zaliapin, I.

2008-12-01

We establish positive correlation between the local spatio-temporal fluctuations of the earthquake magnitude distribution and the occurrence of regional earthquakes. In order to accomplish this goal, we develop a sequential Bayesian statistical estimation framework for the b-value (slope of the Gutenberg-Richter's exponential approximation to the observed magnitude distribution) and for the ratio a(t) between the earthquake intensities in two non-overlapping magnitude intervals. The time-dependent dynamics of these parameters is analyzed using Markov Chain Models (MCM). The main advantage of this approach over the traditional window-based estimation is its "soft" parameterization, which allows one to obtain stable results with realistically small samples. We furthermore discuss a statistical methodology for establishing lagged correlations between continuous and point processes. The developed methods are applied to the observed seismicity of California, Nevada, and Japan on different temporal and spatial scales. We report an oscillatory dynamics of the estimated parameters, and find that the detected oscillations are positively correlated with the occurrence of large regional earthquakes, as well as with small events with magnitudes as low as 2.5. The reported results have important implications for further development of earthquake prediction and seismic hazard assessment methods.

Temporal succession in carbon incorporation from macromolecules by particle-attached bacteria in marine microcosms: Particle-attached bacteria incorporating organic carbon

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

Mayali, Xavier; Stewart, Benjamin; Mabery, Shalini

Here, we investigated bacterial carbon assimilation from stable isotope-labelled macromolecular substrates (proteins; lipids; and two types of polysaccharides, starch and cellobiose) while attached to killed diatom detrital particles during laboratory microcosms incubated for 17 days. Using Chip-SIP (secondary ion mass spectrometry analysis of RNA microarrays), we identified generalist operational taxonomic units (OTUs) from the Gammaproteobacteria, belonging to the genera Colwellia, Glaciecola, Pseudoalteromonas and Rheinheimera, and from the Bacteroidetes, genera Owenweeksia and Maribacter, that incorporated the four tested substrates throughout the incubation period. Many of these OTUs exhibited the highest isotope incorporation relative to the others, indicating that they were likelymore » the most active. Additional OTUs from the Gammaproteobacteria, Bacteroidetes and Alphaproteobacteria exhibited generally (but not always) lower activity and did not incorporate all tested substrates at all times, showing species succession in organic carbon incorporation. We also found evidence to suggest that both generalist and specialist OTUs changed their relative substrate incorporation over time, presumably in response to changing substrate availability as the particles aged. This pattern was demonstrated by temporal succession from relatively higher starch incorporation early in the incubations, eventually switching to higher cellobiose incorporation after 2 weeks.« less

A hybrid spatiotemporal drought forecasting model for operational use

NASA Astrophysics Data System (ADS)

Vasiliades, L.; Loukas, A.

2010-09-01

Drought forecasting plays an important role in the planning and management of natural resources and water resource systems in a river basin. Early and timelines forecasting of a drought event can help to take proactive measures and set out drought mitigation strategies to alleviate the impacts of drought. Spatiotemporal data mining is the extraction of unknown and implicit knowledge, structures, spatiotemporal relationships, or patterns not explicitly stored in spatiotemporal databases. As one of data mining techniques, forecasting is widely used to predict the unknown future based upon the patterns hidden in the current and past data. This study develops a hybrid spatiotemporal scheme for integrated spatial and temporal forecasting. Temporal forecasting is achieved using feed-forward neural networks and the temporal forecasts are extended to the spatial dimension using a spatial recurrent neural network model. The methodology is demonstrated for an operational meteorological drought index the Standardized Precipitation Index (SPI) calculated at multiple timescales. 48 precipitation stations and 18 independent precipitation stations, located at Pinios river basin in Thessaly region, Greece, were used for the development and spatiotemporal validation of the hybrid spatiotemporal scheme. Several quantitative temporal and spatial statistical indices were considered for the performance evaluation of the models. Furthermore, qualitative statistical criteria based on contingency tables between observed and forecasted drought episodes were calculated. The results show that the lead time of forecasting for operational use depends on the SPI timescale. The hybrid spatiotemporal drought forecasting model could be operationally used for forecasting up to three months ahead for SPI short timescales (e.g. 3-6 months) up to six months ahead for large SPI timescales (e.g. 24 months). The above findings could be useful in developing a drought preparedness plan in the region.

Towards an Entropy Stable Spectral Element Framework for Computational Fluid Dynamics

NASA Technical Reports Server (NTRS)

Carpenter, Mark H.; Parsani, Matteo; Fisher, Travis C.; Nielsen, Eric J.

2016-01-01

Entropy stable (SS) discontinuous spectral collocation formulations of any order are developed for the compressible Navier-Stokes equations on hexahedral elements. Recent progress on two complementary efforts is presented. The first effort is a generalization of previous SS spectral collocation work to extend the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to tensor product Legendre-Gauss (LG) points. The LG and LGL point formulations are compared on a series of test problems. Although being more costly to implement, it is shown that the LG operators are significantly more accurate on comparable grids. Both the LGL and LG operators are of comparable efficiency and robustness, as is demonstrated using test problems for which conventional FEM techniques suffer instability. The second effort generalizes previous SS work to include the possibility of p-refinement at non-conforming interfaces. A generalization of existing entropy stability machinery is developed to accommodate the nuances of fully multi-dimensional summation-by-parts (SBP) operators. The entropy stability of the compressible Euler equations on non-conforming interfaces is demonstrated using the newly developed LG operators and multi-dimensional interface interpolation operators.

The Role of Naturally Occurring Stable Isotopes in Mass Spectrometry, Part II: The Instrumentation

PubMed Central

Bluck, Les; Volmer, Dietrich A.

2013-01-01

In the second instalment of this tutorial, the authors explain the instrumentation for measuring naturally occurring stable isotopes, specifically the magnetic sector mass spectrometer. This type of instrument remains unrivalled in its performance for isotope ratio mass spectrometry (IRMS) and the reader is reminded of its operation and its technical advantages for isotope measurements. PMID:23772101

Contour Tracking with a Spatio-Temporal Intensity Moment.

PubMed

Demi, Marcello

2016-06-01

Standard edge detection operators such as the Laplacian of Gaussian and the gradient of Gaussian can be used to track contours in image sequences. When using edge operators, a contour, which is determined on a frame of the sequence, is simply used as a starting contour to locate the nearest contour on the subsequent frame. However, the strategy used to look for the nearest edge points may not work when tracking contours of non isolated gray level discontinuities. In these cases, strategies derived from the optical flow equation, which look for similar gray level distributions, appear to be more appropriate since these can work with a lower frame rate than that needed for strategies based on pure edge detection operators. However, an optical flow strategy tends to propagate the localization errors through the sequence and an additional edge detection procedure is essential to compensate for such a drawback. In this paper a spatio-temporal intensity moment is proposed which integrates the two basic functions of edge detection and tracking.

Effect of Temporal Neocortical Pathology on Seizure Freeness in Adult Patients with Temporal Lobe Epilepsy.

PubMed

Kemerdere, Rahsan; Ahmedov, Merdin Lyutviev; Alizada, Orkhan; Yeni, Seher Naz; Oz, Buge; Tanriverdi, Taner

2018-05-23

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy. Focal cortical dysplasia is the most common dual pathology found in association with the hippocampal sclerosis. In this study, the effect of dual pathology on freedom from seizure was sought in patients with TLE. This study performed a retrospective analysis of patients with TLE who underwent surgery between 2010 and 2017. Histopathologic analysis was performed on patients with and without dual pathology in the temporal neocortex. Seizure outcomes were compared. A total of 54 patients with TLE were included. The rate of overall favorable seizure outcome was found to be 96.3%. In 53.7%, dual pathology was present in the temporal cortices in addition to the hippocampal sclerosis. Patients without dual pathology showed significantly greater freedom from seizure (P = 0.02). Patients without dual pathology had a significantly higher seizure-free rate after anterior temporal resection than patients with dual pathology. Resection of the temporal cortex in addition to mesial temporal structures seems to be reasonable for better seizure outcome. Copyright © 2018 Elsevier Inc. All rights reserved.

Virtual temporal bone dissection system: OSU virtual temporal bone system: development and testing.

PubMed

Wiet, Gregory J; Stredney, Don; Kerwin, Thomas; Hittle, Bradley; Fernandez, Soledad A; Abdel-Rasoul, Mahmoud; Welling, D Bradley

2012-03-01

The objective of this project was to develop a virtual temporal bone dissection system that would provide an enhanced educational experience for the training of otologic surgeons. A randomized, controlled, multi-institutional, single-blinded validation study. The project encompassed four areas of emphasis: structural data acquisition, integration of the system, dissemination of the system, and validation. Structural acquisition was performed on multiple imaging platforms. Integration achieved a cost-effective system. Dissemination was achieved on different levels including casual interest, downloading of software, and full involvement in development and validation studies. A validation study was performed at eight different training institutions across the country using a two-arm randomized trial where study subjects were randomized to a 2-week practice session using either the virtual temporal bone or standard cadaveric temporal bones. Eighty subjects were enrolled and randomized to one of the two treatment arms; 65 completed the study. There was no difference between the two groups using a blinded rating tool to assess performance after training. A virtual temporal bone dissection system has been developed and compared to cadaveric temporal bones for practice using a multicenter trial. There was no statistical difference between practice on the current simulator compared to practice on human cadaveric temporal bones. Further refinements in structural acquisition and interface design have been identified, which can be implemented prior to full incorporation into training programs and used for objective skills assessment. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

Generic emergence of power law distributions and Lévy-Stable intermittent fluctuations in discrete logistic systems

NASA Astrophysics Data System (ADS)

Biham, Ofer; Malcai, Ofer; Levy, Moshe; Solomon, Sorin

1998-08-01

The dynamics of generic stochastic Lotka-Volterra (discrete logistic) systems of the form wi(t+1)=λ(t)wi(t)+aw¯(t)-bwi(t)w¯(t) is studied by computer simulations. The variables wi, i=1,...,N, are the individual system components and w¯(t)=(1/N)∑iwi(t) is their average. The parameters a and b are constants, while λ(t) is randomly chosen at each time step from a given distribution. Models of this type describe the temporal evolution of a large variety of systems such as stock markets and city populations. These systems are characterized by a large number of interacting objects and the dynamics is dominated by multiplicative processes. The instantaneous probability distribution P(w,t) of the system components wi turns out to fulfill a Pareto power law P(w,t)~w-1-α. The time evolution of w¯(t) presents intermittent fluctuations parametrized by a Lévy-stable distribution with the same index α, showing an intricate relation between the distribution of the wi's at a given time and the temporal fluctuations of their average.

Fine root responses to temporal nutrient heterogeneity and competition in seedlings of two tree species with different rooting strategies.

PubMed

Wang, Peng; Shu, Meng; Mou, Pu; Weiner, Jacob

2018-03-01

There is little direct evidence for effects of soil heterogeneity and root plasticity on the competitive interactions among plants. In this study, we experimentally examined the impacts of temporal nutrient heterogeneity on root growth and interactions between two plant species with very different rooting strategies: Liquidambar styraciflua (sweet gum), which shows high root plasticity in response to soil nutrient heterogeneity, and Pinus taeda (loblolly pine), a species with less plastic roots. Seedlings of the two species were grown in sandboxes in inter- and intraspecific combinations. Nutrients were applied in a patch either in a stable (slow-release) or in a variable (pulse) manner. Plant aboveground biomass, fine root mass, root allocation between nutrient patch and outside the patch, and root vertical distribution were measured. L. styraciflua grew more aboveground (40% and 27% in stable and variable nutrient treatment, respectively) and fine roots (41% and 8% in stable and variable nutrient treatment, respectively) when competing with P. taeda than when competing with a conspecific individual, but the growth of P. taeda was not changed by competition from L. styraciflua . Temporal variation in patch nutrient level had little effect on the species' competitive interactions. The more flexible L. styraciflua changed its vertical distribution of fine roots in response to competition from P. taeda , growing more roots in deeper soil layers compared to its roots in conspecific competition, leading to niche differentiation between the species, while the fine root distribution of P. taeda remained unchanged across all treatments. Synthesis . L. styraciflua showed greater flexibility in root growth by changing its root vertical distribution and occupying space of not occupied by P. taeda . This flexibility gave L. styraciflua an advantage in interspecific competition.

Tellurium Stable Isotope Fractionation in Chondritic Meteorites

NASA Astrophysics Data System (ADS)

Fehr, M. A.; Hammond, S. J.; Parkinson, I. J.

2014-09-01

New Te double spike procedures were set up to obtain high-precision accurate Te stable isotope data. Tellurium stable isotope data for 16 chondrite falls are presented, providing evidence for significant Te stable isotope fractionation.

Studies of uranium-sodium suspensions. Part I. Construction and operation of experimental loop

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

Bett, F L; Hilditch, R J; Mepham, R G

1961-08-01

An experimnental uranium- sodium suspension loop was operated for 4320 hr. The design, construction, commissioning, and operation of the loop to the point where a comnplete stable suspension was obtained is described.

High temporal resolution delayed analysis of clinical microdialysate streams† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7an01209h

PubMed Central

Gowers, S. A. N.; Hamaoui, K.; Cunnea, P.; Anastasova, S.; Curto, V. F.; Vadgama, P.; Yang, G.-Z.; Papalois, V.; Drakakis, E. M.; Fotopoulou, C.; Weber, S. G.

2018-01-01

This paper presents the use of tubing to store clinical microdialysis samples for delayed analysis with high temporal resolution, offering an alternative to traditional discrete offline microdialysis sampling. Samples stored in this way were found to be stable for up to 72 days at –80 °C. Examples of how this methodology can be applied to glucose and lactate measurement in a wide range of in vivo monitoring experiments are presented. This paper presents a general model, which allows for an informed choice of tubing parameters for a given storage time and flow rate avoiding high back pressure, which would otherwise cause the microdialysis probe to leak, while maximising temporal resolution. PMID:29336454

Temporal lobe volume predicts Wada memory test performance in patients with mesial temporal sclerosis.

PubMed

Ding, Kan; Gong, Yunhua; Modur, Pradeep N; Diaz-Arrastia, Ramon; Agostini, Mark; Gupta, Puneet; McColl, Roderick; Hays, Ryan; Van Ness, Paul

2016-02-01

The Wada test is widely used in the presurgical evaluation of potential temporal lobectomy patients to predict postoperative memory function. Expected asymmetry (EA), defined as Wada memory lateralized to the nonsurgical hemisphere, or a higher score after injection of the surgical hemisphere would be considered favorable in terms of postoperative memory outcome. However, in some cases, nonlateralized memory (NM) results, with no appreciable asymmetry, may occur because of impaired scores after both injections, often leading to denial of surgery. The reason for such nonlateralized Wada memory in patients with intractable temporal lobe epilepsy (TLE) remains unclear. Given that quantitative morphometric magnetic resonance imaging studies in TLE patients have shown bilateral regional atrophy in temporal and extratemporal structures, we hypothesized that the volume loss in contralateral temporal structures could contribute to nonlateralized Wada memory performance. To investigate this, we examined the relationship between the volume changes of temporal structures and Wada memory scores in patients with intractable TLE with mesial temporal sclerosis (MTS) using an age- and gender-matched control group. Memory was considered nonlateralized if the absolute difference in the total correct recall scores between ipsilateral and contralateral injections was <11%. Among 21 patients, Wada memory was lateralized in 15 and nonlateralized in 6 patients, with all the nonlateralized scores being observed in left TLE. The recall scores after ipsilateral injection were significantly lower in patients with an NM profile than an EA profile (23 ± 14% vs. 59 ± 18% correct recall, p ≤ 0.001). However, the recall scores after contralateral injection were low but similar between the two groups (25 ± 17% vs. 25 ± 15% correct recall, p=0.97). Compared to controls, all the patients showed greater volume loss in the temporal regions. However, patients with a NM profile showed

Temporal variability of particulate organic carbon in the lower Changjiang (Yangtze River) in the post-Three Gorges Dam period: Links to anthropogenic and climate impacts

NASA Astrophysics Data System (ADS)

Wu, Ying; Bao, Hongyan; Yu, Hao; Zhang, Jing; Kattner, Gerhard

2015-11-01

Suspended particles from the lower Changjiang were collected monthly from 2003 to 2011, which corresponds to the three construction periods of the Three Gorges Dam. Organic carbon (%OC), organic carbon to total nitrogen molar ratio, stable carbon isotope, and terrestrial biomarkers were examined. Rating curve studies were applied for the temporal trend analysis. The composition of particulate lignin phenols exhibited clear annual and periodic variations but only minor seasonal changes. Lignin phenol ratios (vanillyl/syringyl and cinnamyl/vanillyl) indicated that the terrigenous organic matter (OM) was primarily composed of woody and nonwoody tissue derived from angiosperm plants. The low-lignin phenol yields (Λ8) in combination with higher acid to aldehyde ratios reflected a substantial contribution from soil OM to the particle samples or modifications during river transport. The temporal shift of the lignin phenol vegetation index with the sediment load during the flood seasons revealed particulate organic matter (POM) erosion from soils and the impact of hydrodynamic processes. The dam operations affected the seasonal variability of terrigenous OM fluxes, although the covariation of lignin and sediment loads with discharged water implies that unseasonal extreme conditions and climate change most likely had larger influences, because decreases in the sediment load and lignin flux alter the structure and composition of particulate OM (POM) on interannual time scales, indicating that they may be driven by climate variability. The modification of the composition and structure of POM will have significant impacts on regional carbon cycles and marine ecosystems.

Neocortical Temporal Lobe Epilepsy

PubMed Central

Bercovici, Eduard; Kumar, Balagobal Santosh; Mirsattari, Seyed M.

2012-01-01

Complex partial seizures (CPSs) can present with various semiologies, while mesial temporal lobe epilepsy (mTLE) is a well-recognized cause of CPS, neocortical temporal lobe epilepsy (nTLE) albeit being less common is increasingly recognized as separate disease entity. Differentiating the two remains a challenge for epileptologists as many symptoms overlap due to reciprocal connections between the neocortical and the mesial temporal regions. Various studies have attempted to correctly localize the seizure focus in nTLE as patients with this disorder may benefit from surgery. While earlier work predicted poor outcomes in this population, recent work challenges those ideas yielding good outcomes in part due to better localization using improved anatomical and functional techniques. This paper provides a comprehensive review of the diagnostic workup, particularly the application of recent advances in electroencephalography and functional brain imaging, in neocortical temporal lobe epilepsy. PMID:22953057

Testing the limits of temporal stability: Willingness to pay values among Grand Canyon whitewater boaters across decades

USGS Publications Warehouse

Neher, Chris J.; Duffield, John; Bair, Lucas S.; Patterson, David A.; Neher, Katherine

2017-01-01

We directly compare trip willingness to pay (WTP) values between 1985 and 2015 stated preference surveys of private party Grand Canyon boaters using identically designed valuation methods. The temporal gap of 30 years between these two studies is well beyond that of any tests of WTP temporal stability in the literature. Comparisons were made of mean WTP estimates for four hypothetical Colorado River flow level scenarios. WTP values from the 1985 survey were adjusted to 2015 levels using the consumer price index. Mean WTP precision was estimated through simulation. No statistically significant differences were detected between the adjusted Bishop et al. (1987) and the current study mean WTP estimates. Examination of pooled models of the data from the studies suggest that while the estimated WTP values are stable over time, the underlying valuation functions may not be, particularly when the data and models are corrected to account for differing bid structures and possible panel effects.

Testing the Limits of Temporal Stability: Willingness to Pay Values among Grand Canyon Whitewater Boaters Across Decades

NASA Astrophysics Data System (ADS)

Neher, Chris; Duffield, John; Bair, Lucas; Patterson, David; Neher, Katherine

2017-12-01

We directly compare trip willingness to pay (WTP) values between 1985 and 2015 stated preference surveys of private party Grand Canyon boaters using identically designed valuation methods. The temporal gap of 30 years between these two studies is well beyond that of any tests of WTP temporal stability in the literature. Comparisons were made of mean WTP estimates for four hypothetical Colorado River flow level scenarios. WTP values from the 1985 survey were adjusted to 2015 levels using the consumer price index. Mean WTP precision was estimated through simulation. No statistically significant differences were detected between the adjusted Bishop et al. (1987) and the current study mean WTP estimates. Examination of pooled models of the data from the studies suggest that while the estimated WTP values are stable over time, the underlying valuation functions may not be, particularly when the data and models are corrected to account for differing bid structures and possible panel effects.

How innate is locomotion in precocial animals? A study on the early development of spatio-temporal gait variables and gait symmetry in piglets.

PubMed

Vanden Hole, Charlotte; Goyens, Jana; Prims, Sara; Fransen, Erik; Ayuso Hernando, Miriam; Van Cruchten, Steven; Aerts, Peter; Van Ginneken, Chris

2017-08-01

Locomotion is one of the most important ecological functions in animals. Precocial animals, such as pigs, are capable of independent locomotion shortly after birth. This raises the question whether coordinated movement patterns and the underlying muscular control in these animals is fully innate or whether there still exists a rapid maturation. We addressed this question by studying gait development in neonatal pigs through the analysis of spatio-temporal gait characteristics during locomotion at self-selected speed. To this end, we made video recordings of piglets walking along a corridor at several time points (from 0 h to 96 h). After digitization of the footfalls, we analysed self-selected speed and spatio-temporal characteristics (e.g. stride and step lengths, stride frequency and duty factor) to study dynamic similarity, intralimb coordination and interlimb coordination. To assess the variability of the gait pattern, left-right asymmetry was studied. To distinguish neuromotor maturation from effects caused by growth, both absolute and normalized data (according to the dynamic similarity concept) were included in the analysis. All normalized spatio-temporal variables reached stable values within 4 h of birth, with most of them showing little change after the age of 2 h. Most asymmetry indices showed stable values, hovering around 10%, within 8 h of birth. These results indicate that coordinated movement patterns are not entirely innate, but that a rapid neuromotor maturation, potentially also the result of the rearrangement or recombination of existing motor modules, takes place in these precocial animals. © 2017. Published by The Company of Biologists Ltd.

Operating Characteristics of the Implicit Learning System Supporting Serial Interception Sequence Learning

ERIC Educational Resources Information Center

Sanchez, Daniel J.; Reber, Paul J.

2012-01-01

The memory system that supports implicit perceptual-motor sequence learning relies on brain regions that operate separately from the explicit, medial temporal lobe memory system. The implicit learning system therefore likely has distinct operating characteristics and information processing constraints. To attempt to identify the limits of the…

A high-powered siren for stable acoustic levitation of dense materials in the earth's gravity

NASA Technical Reports Server (NTRS)

Gammel, Paul M.; Croonquist, Arvid P.; Wang, Taylor G.

1988-01-01

Levitation of large dense samples (e.g., 1-cm diameter steel balls) has been performed in a 1-g environment. A siren was used to study the effects of reflector geometry and variable-frequency operation in order to attain stable acoustic positioning. The harmonic content and spatial distribution of the acoustic field have been investigated. The best stability was obtained with an open reflector system, using a flat lower reflector and a slightly concave upper reflector while operating at a frequency slightly below resonance.

Temporal plus epilepsy: Anatomo-electroclinical subtypes

PubMed Central

Andrade-Machado, René; Benjumea-Cuartas, Vanessa

2016-01-01

Background: Mesial temporal lobe epilepsy (TLE) is a remediable epileptic syndrome. About 40% of patients continue to have seizures after standard temporal lobectomy. It has been suggested that some of these patients could actually suffer from a more complex epileptogenic network. Because a few papers have been dedicated to this topic, we decided to write an article updating this theme. Methods: We performed a literature search using the following terminology: “temporal plus epilepsy and networks,” “temporal plus epilepsy,” “orbito-temporal epilepsy,” “temporo-insular epilepsy,” “temporo-parieto-occipital (TPO) epilepsy,” “parieto-temporal epilepsy,” “intracortical evoked potential and temporal plus epilepsy,” “temporal lobe connectivity and epilepsy,” “intracortical evoked potential and epilepsy surgery,” “role of extratemporal structures in TLE,” “surgical failure after temporal lobectomy,” “Diffusion tensor imaging (DTI) and temporal epilepsy,” and “positron emission tomography (PET) in temporal plus lobe epilepsy” in the existing PubMed databases. We searched only English and Spanish literature. Only papers that fit with the above-mentioned descriptors were included as part of the evidence. Other articles were used to reference some aspects of the temporal plus epilepsy. Results: A total of 48 papers from 2334 were revised. The most frequently reported auras in these groups of patients are gustatory hallucinations, vestibular illusions, laryngeal and throat constriction, atypical distribution of somatosensory symptoms (perioral and hands, bilaterally hands paresthesias, trunk and other). The most common signs are tonic posturing, hemifacial twist, and frequent bilateral clonic movements. Interictal electroencephalographic (EEG) patterns exhibit regional and frequently bilateral spikes and/or slow waves. The first ictal electrographic change is mostly regional. It is important to note that the evidence is

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

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.

Optical bi-stable shutter development/improvement

NASA Astrophysics Data System (ADS)

Lizon, J. L.; Haddad, N.; Castillo, R.

2012-09-01

Two of the VLT instruments (Giraffe and VIMOS) are using the large magnetic E/150 from Prontor (with an aperture diameter of 150 mm). As we were facing an unacceptable number of failures with this component some improvement plan was discussed already in 2004. The final decision for starting this program was conditioned by the decision from the constructor to stop the production. The opportunity was taken to improve the design building a fully bi-stable mechanism in order to reduce the thermal dissipation. The project was developed in collaboration between the two main ESO sites doing the best use of the manpower and of the technical capability available at the two centers. The project took advantage of the laser Mask Manufacturing Unit and the invar sheets used to prepare the VIMOS MOS mask to fabricate the shutter petals. Our paper describes the development including the intensive and long optimization period. To conclude this optimization we proceed with a long life test on two units. These units have demonstrate a very high level of reliability (up to 100 000 cycles without failure which can be estimated to an equivalent 6 years of operation of the instrument) A new bi-stable shutter driver and controller have also been developed. Some of the highlights of this unit are the fully configurable coil driving parameters, usage of braking strategy to dump mechanical vibration and reduce mechanical wearing, configurable usage of OPEN and CLOSE sensors, non volatile storage of parameters, user friendly front panel interface.

Temporal Variability of Oral Microbiota over 10 Months and the Implications for Future Epidemiologic Studies.

PubMed

Vogtmann, Emily; Hua, Xing; Zhou, Liang; Wan, Yunhu; Suman, Shalabh; Zhu, Bin; Dagnall, Casey L; Hutchinson, Amy; Jones, Kristine; Hicks, Belynda D; Sinha, Rashmi; Shi, Jianxin; Abnet, Christian C

2018-05-01

Background: Few studies have prospectively evaluated the association between oral microbiota and health outcomes. Precise estimates of the intrasubject microbial metric stability will allow better study planning. Therefore, we conducted a study to evaluate the temporal variability of oral microbiota. Methods: Forty individuals provided six oral samples using the OMNIgene ORAL kit and Scope mouthwash oral rinses approximately every two months over 10 months. DNA was extracted using the QIAsymphony and the V4 region of the 16S rRNA gene was amplified and sequenced using the MiSeq. To estimate temporal variation, we calculated intraclass correlation coefficients (ICCs) for a variety of metrics and examined stability after clustering samples into distinct community types using Dirichlet multinomial models (DMMs). Results: The ICCs for the alpha diversity measures were high, including for number of observed bacterial species [0.74; 95% confidence interval (CI): 0.65-0.82 and 0.79; 95% CI: 0.75-0.94] from OMNIgene ORAL and Scope mouthwash, respectively. The ICCs for the relative abundance of the top four phyla and beta diversity matrices were lower. Three clusters provided the best model fit for the DMM from the OMNIgene ORAL samples, and the probability of remaining in a specific cluster was high (59.5%-80.7%). Conclusions: The oral microbiota appears to be stable over time for multiple metrics, but some measures, particularly relative abundance, were less stable. Impact: We used this information to calculate stability-adjusted power calculations that will inform future field study protocols and experimental analytic designs. Cancer Epidemiol Biomarkers Prev; 27(5); 594-600. ©2018 AACR . ©2018 American Association for Cancer Research.

Uses of stable isotopes in fish ecology

EPA Science Inventory

Analyses of fish tissues (other than otoliths) for stable isotope ratios can provide substantial information on fish ecology, including physiological ecology. Stable isotopes of nitrogen and carbon frequently are used to determine the mix of diet sources for consumers. Stable i...

Spatio-temporal evaluation of plant height in corn via unmanned aerial systems

NASA Astrophysics Data System (ADS)

Varela, Sebastian; Assefa, Yared; Vara Prasad, P. V.; Peralta, Nahuel R.; Griffin, Terry W.; Sharda, Ajay; Ferguson, Allison; Ciampitti, Ignacio A.

2017-07-01

Detailed spatial and temporal data on plant growth are critical to guide crop management. Conventional methods to determine field plant traits are intensive, time-consuming, expensive, and limited to small areas. The objective of this study was to examine the integration of data collected via unmanned aerial systems (UAS) at critical corn (Zea mays L.) developmental stages for plant height and its relation to plant biomass. The main steps followed in this research were (1) workflow development for an ultrahigh resolution crop surface model (CSM) with the goal of determining plant height (CSM-estimated plant height) using data gathered from the UAS missions; (2) validation of CSM-estimated plant height with ground-truthing plant height (measured plant height); and (3) final estimation of plant biomass via integration of CSM-estimated plant height with ground-truthing stem diameter data. Results indicated a correlation between CSM-estimated plant height and ground-truthing plant height data at two weeks prior to flowering and at flowering stage, but high predictability at the later growth stage. Log-log analysis on the temporal data confirmed that these relationships are stable, presenting equal slopes for both crop stages evaluated. Concluding, data collected from low-altitude and with a low-cost sensor could be useful in estimating plant height.

Anatomy of the Temporal Lobe

PubMed Central

Kiernan, J. A.

2012-01-01

Only primates have temporal lobes, which are largest in man, accommodating 17% of the cerebral cortex and including areas with auditory, olfactory, vestibular, visual and linguistic functions. The hippocampal formation, on the medial side of the lobe, includes the parahippocampal gyrus, subiculum, hippocampus, dentate gyrus, and associated white matter, notably the fimbria, whose fibres continue into the fornix. The hippocampus is an inrolled gyrus that bulges into the temporal horn of the lateral ventricle. Association fibres connect all parts of the cerebral cortex with the parahippocampal gyrus and subiculum, which in turn project to the dentate gyrus. The largest efferent projection of the subiculum and hippocampus is through the fornix to the hypothalamus. The choroid fissure, alongside the fimbria, separates the temporal lobe from the optic tract, hypothalamus and midbrain. The amygdala comprises several nuclei on the medial aspect of the temporal lobe, mostly anterior the hippocampus and indenting the tip of the temporal horn. The amygdala receives input from the olfactory bulb and from association cortex for other modalities of sensation. Its major projections are to the septal area and prefrontal cortex, mediating emotional responses to sensory stimuli. The temporal lobe contains much subcortical white matter, with such named bundles as the anterior commissure, arcuate fasciculus, inferior longitudinal fasciculus and uncinate fasciculus, and Meyer's loop of the geniculocalcarine tract. This article also reviews arterial supply, venous drainage, and anatomical relations of the temporal lobe to adjacent intracranial and tympanic structures. PMID:22934160

Contributions of primate prefrontal cortex and medial temporal lobe to temporal-order memory.

PubMed

Naya, Yuji; Chen, He; Yang, Cen; Suzuki, Wendy A

2017-12-19

Neuropsychological and neurophysiological studies have emphasized the role of the prefrontal cortex (PFC) in maintaining information about the temporal order of events or items for upcoming actions. However, the medial temporal lobe (MTL) has also been considered critical to bind individual events or items to their temporal context in episodic memory. Here we characterize the contributions of these brain areas by comparing single-unit activity in the dorsal and ventral regions of macaque lateral PFC (d-PFC and v-PFC) with activity in MTL areas including the hippocampus (HPC), entorhinal cortex, and perirhinal cortex (PRC) as well as in area TE during the encoding phase of a temporal-order memory task. The v-PFC cells signaled specific items at particular time periods of the task. By contrast, MTL cortical cells signaled specific items across multiple time periods and discriminated the items between time periods by modulating their firing rates. Analysis of the temporal dynamics of these signals showed that the conjunctive signal of item and temporal-order information in PRC developed earlier than that seen in v-PFC. During the delay interval between the two cue stimuli, while v-PFC provided prominent stimulus-selective delay activity, MTL areas did not. Both regions of PFC and HPC exhibited an incremental timing signal that appeared to represent the continuous passage of time during the encoding phase. However, the incremental timing signal in HPC was more prominent than that observed in PFC. These results suggest that PFC and MTL contribute to the encoding of the integration of item and timing information in distinct ways.