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Sample records for operators temporally stable

  1. 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.

  2. Representing operations procedures using temporal dependency networks

    NASA Technical Reports Server (NTRS)

    Fayyad, Kristina E.; Cooper, Lynne P.

    1993-01-01

    DSN Link Monitor & Control (LMC) operations consist primarily of executing procedures to configure, calibrate, test, and operate a communications link between an interplanetary spacecraft and its mission control center. Currently the LMC operators are responsible for integrating procedures into an end-to-end series of steps. The research presented in this paper is investigating new ways of specifying operations procedures that incorporate the insight of operations, engineering, and science personnel to improve mission operations. The paper describes the rationale for using Temporal Dependency Networks (TDN's) to represent the procedures, a description of how the data is acquired, and the knowledge engineering effort required to represent operations procedures. Results of operational tests of this concept, as implemented in the LMC Operator Assistant Prototype (LMCOA), are also presented.

  3. Temporal dietary shift in jellyfish revealed by stable isotope analysis.

    PubMed

    Javidpour, Jamileh; Cipriano-Maack, Ashlie N; Mittermayr, Agnes; Dierking, Jan

    A temporal change in the stable isotope (SI) composition of jellyfish in the Kiel Fjord, Western Baltic Sea, was documented by analyzing δ(13)C, δ(15)N and δ(34)S of bell tissue of Aurelia aurita and Cyanea capillata in the period between June and October 2011. A strong and significant temporal change in all SI values of A. aurita was found, including an increase of ~3 ‰ in δ(13)C, a decrease of ~4 ‰ in δ(15)N and sharp decline of ~7 ‰ in δ(34)S. While knowledge gaps in jellyfish isotope ecology, in particular the lack of reliable trophic enrichment factors, call for a conservative interpretation of our data, observed changes in particular in δ(34)S, as indicated by means of a MixSIR mixing model, would be consistent with a temporal dietary shift in A. aurita from mesozooplankton (>150 µm) to microplankton and small re-suspended particles (0.8-20 µm) from the benthos. Presence of a hitherto unidentified food source not included in the model could also contribute to the shift. During the 2-month occurrence of C. capillata, its isotope composition remained stable and was consistent with a mainly mesozooplanktonic diet. Mixing model output, mainly driven by δ(34)S values, indicated a lower proportion of A. aurita in the diet of C. capillata than previously reported, and thus to a potentially lesser importance of intraguild predation among jellyfish in the Kiel Fjord. Overall, our results clearly highlighted the potential for substantial intraspecific isotopic seasonal variation in jellyfish, which should be taken into account in future feeding ecology studies on this group.

  4. Stable, inflatable life raft for high seas rescue operations

    NASA Technical Reports Server (NTRS)

    Barnett, J. H., Jr.; Harrison, F.; Marak, R.; Radnofsky, M. I.

    1971-01-01

    Raft is easily deployed and highly maneuverable in water. It has false bottom of water ballast containers attached to underside, making it exceptionally stable platform from which swimmers can operate. Raft is attachable to external moorings.

  5. Temporally And Thermally Stable Iron/Nickel Alloy

    NASA Technical Reports Server (NTRS)

    Sokolowski, Witold M.; O'Donnell, Timothy P.; Lane, Marc S.; Hsieh, Cheng H.

    1995-01-01

    Specially prepared version of commerical low-thermal-expansion iron/nickel alloy exhibits unprecedented thermal and temporal dimensional stability. Consists of high-purity powder-metallurgy process followed by heat treatment. High-purity processing imparts unusual combination of properties.

  6. Fiber Optic Cable Thermal Preparation to Ensure Stable Operation

    NASA Technical Reports Server (NTRS)

    Thoames Jr, William J.; Chuska, Rick F.; LaRocca, Frank V.; Switzer, Robert C.; Macmurphy, Shawn L.; Ott, Melanie N.

    2008-01-01

    Fiber optic cables are widely used in modern systems that must provide stable operation during exposure to changing environmental conditions. For example, a fiber optic cable on a satellite may have to reliably function over a temperature range of -50 C up to 125 C. While the system requirements for a particular application will dictate the exact method by which the fibers should be prepared, this work will examine multiple ruggedized fibers prepared in different fashions and subjected to thermal qualification testing. The data show that if properly conditioned the fiber cables can provide stable operation, but if done incorrectly, they will have large fluctuations in transmission.

  7. Temporally stable genetic structure of heavily exploited Atlantic herring (Clupea harengus) in Swedish waters.

    PubMed

    Larsson, L C; Laikre, L; André, C; Dahlgren, T G; Ryman, N

    2010-01-01

    Information on the temporal stability of genetic structures is important to permit detection of changes that can constitute threats to biological resources. Large-scale harvesting operations are known to potentially alter the composition and reduce the variability of populations, and Atlantic herring (Clupea harengus) has a long history of heavy exploitation. In the Baltic Sea and Skagerrak waters, the census population sizes have declined by 35-50% over the last three decades. We compared the genetic structure of Atlantic herring in these waters sampled at least two different times between 1979 and 2003 by assaying 11 allozyme and nine microsatellite loci. We cannot detect any changes in the amount of genetic variation or spatial structure, and differentiation is weak with overall F(ST)=0.003 among localities for the older samples and F(ST)=0.002 for the newer ones. There are indications of temporal allele frequency changes, particularly in one of five sampling localities that is reflected in a relatively small local N(e) estimate of c. 400. The previously identified influence of selection at the microsatellite locus Cpa112 remains stable over the 24-year period studied here. Despite little genetic differentiation, migration among localities appears small enough to permit demographic independence between populations.

  8. Developing Temporal Markers to Profile Operational Errors

    DTIC Science & Technology

    2006-08-01

    ATC subject matter experts ( SMEs ) to assist in the devel- opment of a comprehensive list of TMs. Their collective experience included 87 years of...controllers involved. The SMEs were provided with our definition of a temporal marker and a list of some TM examples, such as the time when the aircraft...the first control instruction to the pilot. Procedure The SMEs convened as a group on several occasions to create an exhaustive list of TMs. An

  9. Spatial and Temporal Trends in Stable Carbon and Oxygen Isotope Ratios of Juvenile Winter Flounder

    EPA Science Inventory

    Isotopic ratios of fish otoliths have been used in numerous studies as natural tags or markers to aid the study of connectivity among fish populations. We investigated the use of spatial and temporal changes in the stable carbon and oxygen isotope ratios of otoliths to different...

  10. Spatial and Temporal Trends in Stable Carbon and Oxygen Isotope Ratios of Juvenile Winter Flounder

    EPA Science Inventory

    Isotopic ratios of fish otoliths have been used in numerous studies as natural tags or markers to aid the study of connectivity among fish populations. We investigated the use of spatial and temporal changes in the stable carbon and oxygen isotope ratios of otoliths to different...

  11. Spectral decomposition of fractional operators and a reflected stable semigroup

    NASA Astrophysics Data System (ADS)

    Patie, P.; Zhao, Y.

    2017-02-01

    In this paper, we provide the spectral decomposition in Hilbert space of the C0-semigroup P and its adjoint P ˆ having as generator, respectively, the Caputo and the right-sided Riemann-Liouville fractional derivatives of index 1 < α < 2. These linear operators, which are non-local and non-self-adjoint, appear in many recent studies in applied mathematics and also arise as the infinitesimal generators of some substantial processes such as the reflected spectrally negative α-stable process. Our approach relies on intertwining relations that we establish between these semigroups and the semigroup of a Bessel type process whose generator is a self-adjoint second order differential operator. In particular, from this commutation relation, we characterize the positive real axis as the continuous point spectrum of P and provide a power series representation of the corresponding eigenfunctions. We also identify the positive real axis as the residual spectrum of the adjoint operator P ˆ and elucidate its role in the spectral decomposition of these operators. By resorting to the concept of continuous frames, we proceed by investigating the domain of the spectral operators and derive two representations for the heat kernels of these semigroups. As a by-product, we also obtain regularity properties for these latter and also for the solution of the associated Cauchy problem.

  12. Encapsulated graphene field-effect transistors for air stable operation

    SciTech Connect

    Alexandrou, Konstantinos Kymissis, Ioannis; Petrone, Nicholas; Hone, James

    2015-03-16

    In this work, we report the fabrication of encapsulated graphene field effects transistors (GFETs) with excellent air stability operation in ambient environment. Graphene's 2D nature makes its electronics properties very sensitive to the surrounding environment, and thus, non-encapsulated graphene devices show extensive vulnerability due to unintentional hole doping from the presence of water molecules and oxygen limiting their performance and use in real world applications. Encapsulating GFETs with a thin layer of parylene-C and aluminum deposited on top of the exposed graphene channel area resulted in devices with excellent electrical performance stability for an extended period of time. Moisture penetration is reduced significantly and carrier mobility degraded substantially less when compared to non-encapsulated control devices. Our CMOS compatible encapsulation method minimizes the problems of environmental doping and lifetime performance degradation, enabling the operation of air stable devices for next generation graphene-based electronics.

  13. Temporal discrimination learning of operant feeding in goldfish (Carassius auratus)

    PubMed Central

    Gee, Philip; Stephenson, David; Wright, Donald E.

    1994-01-01

    Operant temporal discrimination learning was investigated in goldfish. In the first experiment, there was a fixed daily change in illumination. Eight subjects were trained to operate a lever that reinforced each press with food. The period during which responses were reinforced was then progressively reduced until it was 1 hr in every 24. The final 1-hr feeding schedule was maintained over 4 weeks. The feeding period commenced at the same time each day throughout. The food dispensers were then made inactive, and a period of extinction ensued for 6 days. The pattern of responding suggested that the fish were able to exhibit temporal discrimination in anticipation of feeding time. This pattern of responding persisted for a limited number of days during the extinction procedure. The second experiment produced evidence that operant temporal discrimination could develop under continuous illumination. PMID:16812735

  14. Daytime warming lowers community temporal stability by reducing the abundance of dominant, stable species.

    PubMed

    Yang, Zhongling; Zhang, Qian; Su, Fanglong; Zhang, Chunhui; Pu, Zhichao; Xia, Jianyang; Wan, Shiqiang; Jiang, Lin

    2017-01-01

    Daytime warming and nighttime warming have the potential to influence plant community structure and ecosystem functions. However, their impacts on ecological stability remain largely unexplored. We conducted an eight-year field experiment to compare the effects of daytime and nighttime warming on the temporal stability of a temperate steppe in northern China. Our results showed that the cover and stability of dominant species, stability of subordinate species, and compensatory dynamics among species strongly influenced community-level stability. However, daytime, but not nighttime, warming significantly reduced community temporal stability mainly through the reduction in the abundance of dominant, stable species. These findings demonstrate the differential effects of daytime and nighttime warming on community stability and emphasize the importance of understanding the changes of dominant species for accurately predicting community dynamics under climate warming.

  15. Compact and stable temporally magnified tomography using a phase-locked broadband source.

    PubMed

    Li, Bowen; Wei, Xiaoming; Tan, Sisi; Kang, Jiqiang; Wong, Kenneth K Y

    2016-04-01

    The temporally magnified tomography system is further improved in terms of resolution and imaging stability. We simplify the system configuration and improve the axial resolution simultaneously by utilizing a stabilized all-fiber broadband source. The highly stable spectrum of the source assisted by a phase-locked loop guarantees an improved imaging quality. In addition, the impact of the repetition-rate fluctuation of the source to the system stability is analyzed, which also applies to other temporal imaging systems. Achieving a 90-μm in-air resolution at 89-MHz A-scan rate and improved stability, we are taking one major step toward the practical application of this new optical tomographic modality.

  16. Highly efficient temporally stable narrow linewidth cryogenically cooled Yb-fiber laser.

    PubMed

    Jelger, P; Seger, K; Pasiskevicius, V; Laurell, F

    2009-05-11

    Cryogenic cooling is an effective way of increasing the efficiency in many solid-state lasers. In fiber lasers however, while the efficiency is increased, a reduced reabsorption in combination with reduced homogeneous broadening tends to broaden the linewidth, yielding a low spectral power density of the laser emission. In this work we lock a cryogenically-cooled Yb-doped fiber laser with a volume Bragg grating to overcome this problem and achieve a temporally stable narrow linewidth highly efficient laser. We extract 11.4-W of output power in spectral window of less than 0.4-nm with 14.5-W of launched pump light.

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

    USGS Publications Warehouse

    Paxton, Kristina L.; van Riper, Charles

    2006-01-01

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

  18. Cluster Analysis in Sociometric Research: A Pattern-Oriented Approach to Identifying Temporally Stable Peer Status Groups of Girls

    ERIC Educational Resources Information Center

    Zettergren, Peter

    2007-01-01

    A modern clustering technique was applied to age-10 and age-13 sociometric data with the purpose of identifying longitudinally stable peer status clusters. The study included 445 girls from a Swedish longitudinal study. The identified temporally stable clusters of rejected, popular, and average girls were essentially larger than corresponding…

  19. Cluster Analysis in Sociometric Research: A Pattern-Oriented Approach to Identifying Temporally Stable Peer Status Groups of Girls

    ERIC Educational Resources Information Center

    Zettergren, Peter

    2007-01-01

    A modern clustering technique was applied to age-10 and age-13 sociometric data with the purpose of identifying longitudinally stable peer status clusters. The study included 445 girls from a Swedish longitudinal study. The identified temporally stable clusters of rejected, popular, and average girls were essentially larger than corresponding…

  20. A spatio-temporal extension to the map cube operator

    NASA Astrophysics Data System (ADS)

    Alzate, Juan C.; Moreno, Francisco J.; Echeverri, Jaime

    2012-09-01

    OLAP (On Line Analytical Processing) is a set of techniques and operators to facilitate the data analysis usually stored in a data warehouse. In this paper, we extend the functionality of an OLAP operator known as Map Cube with the definition and incorporation of a function that allows the formulation of spatio-temporal queries. For example, consider a data warehouse about crimes that includes data about the places where the crimes were committed. Suppose we want to find and visualize the trajectory (a trajectory is just the path that an object follows through space as a function of time) of the crimes of a suspect beginning with his oldest crime and ending with his most recent one. In order to meet this requirement, we extend the Map Cube operator.

  1. Highly enhanced and temporally stable field emission from MWCNTs grown on aluminum coated silicon substrate

    SciTech Connect

    Sreekanth, M.; Ghosh, S. Patra, R.; Srivastava, P.

    2015-06-15

    In this work, a detailed field emission study of multi-walled carbon nanotubes (MWCNTs) grown on Si and Al coated Si substrates is reported. Morphological and microstructural studies of the films show higher entanglement of CNTs in the case of CNT/Si film as compared to CNT/Al/Si film. Raman studies show that the defect mediated peak (D) is substantially suppressed as compared to graphitic peak (G) resulting in significant reduction in I{sub D}/I{sub G} value in CNT/Al/Si film. Field emission (FE) current density of CNT/Al/Si film (∼25 mA/cm{sup 2}) is significantly higher as compared to that of CNT/Si film (∼1.6 mA/cm{sup 2}). A substantial improvement in temporal stability is also observed in CNT/Al/Si film. This enhancement in field emission current is attributed to strong adhesion between substrate and CNTs, low work function, high local field enhancement factor at the CNT tips and less entanglement of CNTs grown on Al/Si. The temporally stable CNT/Al/Si cold cathode can be a potential candidate to replace conventional electron sources in prototype devices.

  2. Pre-operative preparation for otologic surgery: temporal bone simulation

    PubMed Central

    Sethia, Rishabh; Wiet, Gregory J.

    2015-01-01

    Purpose of review The field of temporal bone simulation (TBS) has largely focused on the development and validation of simulators as training and assessment tools. However, as technology has progressed over the years, researchers have envisioned new clinical applications for simulators extending to pre-operative surgical planning and case rehearsal. The purpose of this article is to review the current state of the art in TBS and to highlight recent advancements in the field. Due to space limitations, we will limit our discussion to computer-based virtual reality (VR) simulators. Recent findings A review of the recent literature on TBS revealed very limited application of VR simulators for pre-operative preparation. Current evidence suggests limitations in fidelity preclude successful patient-specific case rehearsal using VR simulation. Further investigation and clinical evaluation are required to validate its use outside of training and skill assessment. Summary This article provides an overview of the current use of VR simulators with emphasis on pre-operative planning. We evaluate the limitations of the technology, and discuss potential areas of improvement for the future. More studies are necessary to assess the value of VR simulation for pre-operative preparation. PMID:26339966

  3. Stable Associations Masked by Temporal Variability in the Marine Copepod Microbiome.

    PubMed

    Moisander, Pia H; Sexton, Andrew D; Daley, Meaghan C

    2015-01-01

    Copepod-bacteria interactions include permanent and transient epi- and endobiotic associations that may play roles in copepod health, transfer of elements in the food web, and biogeochemical cycling. Microbiomes of three temperate copepod species (Acartia longiremis, Centropages hamatus, and Calanus finmarchicus) from the Gulf of Maine were investigated during the early summer season using high throughput amplicon sequencing. The most prominent stable component of the microbiome included several taxa within Gammaproteobacteria, with Pseudoalteromonas spp. especially abundant across copepod species. These Gammaproteobacteria appear to be promoted by the copepod association, likely benefitting from nutrient enriched microenvironments on copepods, and forming a more important part of the copepod-associated community than Vibrio spp. during the cold-water season in this temperate system. Taxon-specific associations included an elevated relative abundance of Piscirickettsiaceae and Colwelliaceae on Calanus, and Marinomonas sp. in Centropages. The communities in full and voided gut copepods had distinct characteristics, thus the presence of a food-associated microbiome was evident, including higher abundance of Rhodobacteraceae and chloroplast sequences in the transient communities. The observed variability was partially explained by collection date that may be linked to factors such as variable time since molting, gender differences, and changes in food availability and type over the study period. While some taxon-specific and stable associations were identified, temporal changes in environmental conditions, including food type, appear to be key in controlling the composition of bacterial communities associated with copepods in this temperate coastal system during the early summer.

  4. Passive coherent combining of CEP-stable few-cycle pulses from a temporally divided hollow fiber compressor.

    PubMed

    Jacqmin, Hermance; Jullien, Aurélie; Mercier, Brigitte; Hanna, Marc; Druon, Frédéric; Papadopoulos, Dimitrios; Lopez-Martens, Rodrigo

    2015-03-01

    We demonstrate a simple and robust passive coherent combining technique for temporal compression of millijoule energy laser pulses down to few-cycle duration in a gas-filled hollow fiber. High combining efficiency is achieved by using carefully oriented calcite plates for temporal pulse division and recombination. Carrier-envelope phase (CEP)-stable, 6-fs, 800-nm pulses with more than 0.6 mJ energy are routinely generated. This method could aid in the energy scaling of CEP-stable hollow-fiber compressor systems.

  5. Temporal and Spatial Variation of Surface Water Stable Isotopes in the Marys River Basin, Oregon

    NASA Astrophysics Data System (ADS)

    Nickolas, L. B.; Segura, C.; Brooks, J. R.

    2015-12-01

    Understanding the temporal and spatial variability of water sources within a basin is vital to our ability to manage the impacts of climate variability and land cover change. Water stable isotopes can be used as a tool to determine geographic and seasonal sources of water at the basin scale. Previous studies in the Coastal Range of Oregon reported that the variation in the isotopic signatures of surface water does not conform to the commonly observed "rainout effect", which exhibits a trend of increasing isotopic depletion with rising elevation. The primary purpose of this research is to investigate the mechanisms governing seasonal and spatial variations in the isotopic signature of surface waters within the Marys River Basin, located in the Oregon Coastal Range. We hypothesize that catchment orientation, drainage area, geology, and topography act as controlling factors on groundwater flow, storage, and atmospheric moisture cycling, which explain variations in source water contribution. Surface water and precipitation samples were collected every 2-3 weeks for isotopic analysis of δ18O and δ2H for one year. Preliminary results indicate a significant difference (p<0.001) in isotopic signature between watersheds underlain by basalt and sandstone. The degree of separation is the most distinct during the summer when low flows likely reflect deeper groundwater sources, whereas isotopic signatures during the rainy season (fall & winter) show a greater degree of similarity between the two lithologies. These findings indicate that the more permeable sandstone formations may be hydrologically connected to enriched water sources on the windward side of the Coastal Range that sustain baseflow within catchments on the leeward side, while streams draining basalt catchments are fed by a more depleted source of water (e.g. precipitation originating within the Marys River Basin).

  6. Temporal characterization of bacteria in hayrings serving as stable fly larval development sites

    USDA-ARS?s Scientific Manuscript database

    Stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae) are important pests of pastured cattle, reducing weight gains, and causing discomfort to the animals. The focus of stable fly control has historically been on preventing adult stable flies from biting cattle. While the adult files biting t...

  7. Note: A new regulation method of stable operation of high power cathode ion source

    SciTech Connect

    Jiang, C. C.; Xie, Y. H. Hu, C. D.; Xie, Y. L.; Liu, S.; Liang, L. Z.; Liu, Z. M.

    2015-05-15

    The hot cathode ion source will tend to be unstable when operated with high power and long pulse. In order to achieve stable operation, a new regulation method based on the arc power (discharge power) feedback control was designed and tested on the hot cathode ion source test bed with arc discharge and beam extraction. The results show that the new regulation method can achieve stable arc discharge and beam extraction. It verifies the success of feedback control of arc source with arc power.

  8. Application Of Stable Isotope Analysis To Study Temporal Changes In Foraging Ecology In A Highly Endangered Amphibian

    PubMed Central

    Gillespie, J. Hayley

    2013-01-01

    Background Understanding dietary trends for endangered species may be essential to assessing the effects of ecological disturbances such as habitat modification, species introductions or global climate change. Documenting temporal variation in prey selection may also be crucial for understanding population dynamics. However, the rarity, secretive behaviours and obscure microhabitats of some endangered species can make direct foraging observations difficult or impossible. Furthermore, the lethality or invasiveness of some traditional methods of dietary analysis (e.g. gut contents analysis, gastric lavage) makes them inappropriate for such species. Stable isotope analysis facilitates non-lethal, indirect analysis of animal diet that has unrealized potential in the conservation of endangered organisms, particularly amphibians. Methodology/findings I determined proportional contributions of aquatic macroinvertebrate prey to the diet of an endangered aquatic salamander Eurycea sosorum over a two-year period using stable isotope analysis of 13/12C and 15/14N and the Bayesian stable isotope mixing model SIAR. I calculated Strauss’ dietary electivity indices by comparing these proportions with changing relative abundance of potential prey species through time. Stable isotope analyses revealed that a previously unknown prey item (soft-bodied planarian flatworms in the genus Dugesia) made up the majority of E. sosorum diet. Results also demonstrate that E. sosorum is an opportunistic forager capable of diet switching to include a greater proportion of alternative prey when Dugesia populations decline. There is also evidence of intra-population dietary variation. Conclusions/significance Effective application of stable isotope analysis can help circumvent two key limitations commonly experienced by researchers of endangered species: the inability to directly observe these species in nature and the invasiveness or lethality of traditional methods of dietary analysis. This

  9. Stable isotopes in river waters in the Tajik Pamirs: regional and temporal characteristics.

    PubMed

    Meier, Christiane; Knoche, Malte; Merz, Ralf; Weise, Stephan M

    2013-01-01

    The Gunt River catchment in the Central Pamirs is a representative of the headwater catchments of the Aral Sea Basin. It covers 14,000 km(2), spanning altitudes between 2000 and 6700 m a.s.l. In a monitoring network, water samples were taken at 30 sampling points every month and analysed for the stable water isotopes ((18)O and (2)H). Our first results show δ(2)H values in the range from-131.2 to-94.9 ‰ and δ(18)O values from-18.0 to-14.0 ‰. The stable isotope patterns in the catchment seem to follow a systematic way, dominated by an altitude effect with a mean Δ δ(2)H=-3.6 ‰/100 m. The observed seasonal variations can be explained by geographical aspects such as the influence of different wind systems as well as melting processes.

  10. Spatial and temporal analysis of stable isotopes in tap water across China

    NASA Astrophysics Data System (ADS)

    Zhao, S.; Hu, H.; Tian, F.; Tie, Q.

    2015-12-01

    Stable isotopes in water (δ2H and δ18O) are important indicators of hydrological and ecological pattern and process. Water isotopes have been used to trace atmospheric moisture source, identify source of groundwater and surface water charge, reconstruct paleoclimate, and so on. Tap water appears to reflect pervasive features of regional integrated hydrological process. China is a large-size country with high variations in both environmental and geographical factors including temperature, precipitation amount, relative humidity, latitude, altitude et al. Here we present a first national-scale survey on stable isotope of tap water across China. More than 1000 tap water samples have been collected from 93 cities across China by monthly between December 2014 and November 2015. Stable isotope composition of tap water ranged from -132.1‰ to -25.6‰ (δ2H) and from -17.5‰ to -4.2‰ (δ18O). The Meteoric Water Line is δ2H = 7.77 δ18O + 5.79 (r2 = 0.95) and the LMWL of Chinese precipitation is δ2H =7.6δ18O+ 9.94 (r2= 0.97). Spatial distribution of stable isotopes present typical "continental effect", isotope values generally decrease from coastal regions to inland. Isotopes in different regions present different correlations with temperature, precipitation amount, latitude and altitude as a result of varied moisture source and local water supply. The results of the study could provide mapping information of tap water for fundamental isotope hydrological studies in different regions of China.

  11. Temporal variation in mycorrhizal diversity and carbon and nitrogen stable isotope abundance in the wintergreen meadow orchid Anacamptis morio.

    PubMed

    Ercole, Enrico; Adamo, Martino; Rodda, Michele; Gebauer, Gerhard; Girlanda, Mariangela; Perotto, Silvia

    2015-02-01

    Many adult orchids, especially photoautotrophic species, associate with a diverse range of mycorrhizal fungi, but little is known about the temporal changes that might occur in the diversity and functioning of orchid mycorrhiza during vegetative and reproductive plant growth. Temporal variations in the spectrum of mycorrhizal fungi and in stable isotope natural abundance were investigated in adult plants of Anacamptis morio, a wintergreen meadow orchid. Anacamptis morio associated with mycorrhizal fungi belonging to Tulasnella, Ceratobasidium and a clade of Pezizaceae (Ascomycetes). When a complete growing season was investigated, multivariate analyses indicated significant differences in the mycorrhizal fungal community. Among fungi identified from manually isolated pelotons, Tulasnella was more common in autumn and winter, the pezizacean clade was very frequent in spring, and Ceratobasidium was more frequent in summer. By contrast, relatively small variations were found in carbon (C) and nitrogen (N) stable isotope natural abundance, A. morio samples showing similar (15)N enrichment and (13)C depletion at the different sampling times. These observations suggest that, irrespective of differences in the seasonal environmental conditions, the plant phenological stages and the associated fungi, the isotopic content in mycorrhizal A. morio remains fairly constant over time.

  12. Temporal expectation and spectral expectation operate in distinct fashion on neuronal populations.

    PubMed

    Hsu, Yi-Fang; Hämäläinen, Jarmo A; Waszak, Florian

    2013-11-01

    The formation of temporal expectation (i.e., the prediction of "when") is of prime importance to sensory processing. It can modulate sensory processing at early processing stages probably via the entrainment of low-frequency neuronal oscillations in the brain. However, sensory predictions involve not only temporal expectation but also spectral expectation (i.e., the prediction of "what"). Here we investigated how temporal expectation may interrelate with spectral expectation by explicitly setting up temporal expectation and spectral expectation in a target detection task. We found that reaction time (RT) was shorter when targets were temporally expected than when they were temporally unexpected. The temporal expectation effect was larger with than without spectral expectation. However, this interaction in the behavioural data did not result from an interaction in the electroencephalography (EEG), where we observed independent main effects of temporal expectation and spectral expectation. More precisely, we found that the N1 and P2 event-related potential (ERP) components and the entrainment of low-frequency neuronal oscillations were exclusively modulated by temporal expectation, whilst only the P3 ERP component was modulated by spectral expectation. Our results, thus, support the idea that temporal expectation and spectral expectation operate in distinct fashion on neuronal populations.

  13. Effects of temporal fluctuations, fluid density effects and heterogeneity on mixing of two fluids for a stable stratification

    NASA Astrophysics Data System (ADS)

    Pool, Maria; Dentz, Marco; Post, Vincent E. A.

    2017-04-01

    Mixing and dispersion in coastal aquifers are controlled by density variations, which are influenced by temporal fluctuations on multiple time-scales ranging from days (tides), seasons (pumping and recharge) to glacial cycles (regression and transgressions). Transient forcing effects lead to a complex space and time dependent flow response which induces enhanced spreading and mixing of dissolved substances. We study effective mixing and solute transport in temporally fluctuating flow for a stable stratification of two fluids of different density using detailed numerical simulation as well as accurate column experiments. For the homogeneous case, we quantify the observed transport behaviors and interface evolution by a time-averaged model that is obtained from a two-scale expansion of the full transport problem, and derive explicit expressions for the center of mass and width of the mixing zone between the two fluids (Pool et al., 2016). We find that the magnitude of transient-driven mixing is mainly controlled by the hydraulic diffusivity, the period, and the initial interface location. For the heterogeneous case, transient forcing and density-dependent transport is investigated considering multigaussian random log conductivity fields and more complex heterogeneous fields characterized by connected patterns of high and low conductivity. We find that the mixing potential and 'hot spots' are directly related to the deformation properties and topology of the flow field, specifically its stretching behavior in response to temporal fluctuations. We also find that gravity forces due to density variations cause smoother concentration distribution leading to a decrease in the width of the transition zone. However the mixing potential is similar as the one obtained with constant density. Reference: Pool, M., M. Dentz, and V.E.A. Post (2016), Transient forcing effects on mixing of two fluids for a stable stratification, Water Resour. Res., 52, 7178-7197, doi:10.1002/2016WR

  14. A novel averaging technique for discrete entropy-stable dissipation operators for ideal MHD

    NASA Astrophysics Data System (ADS)

    Derigs, Dominik; Winters, Andrew R.; Gassner, Gregor J.; Walch, Stefanie

    2017-02-01

    Entropy stable schemes can be constructed with a specific choice of the numerical flux function. First, an entropy conserving flux is constructed. Secondly, an entropy stable dissipation term is added to this flux to guarantee dissipation of the discrete entropy. Present works in the field of entropy stable numerical schemes are concerned with thorough derivations of entropy conservative fluxes for ideal MHD. However, as we show in this work, if the dissipation operator is not constructed in a very specific way, it cannot lead to a generally stable numerical scheme. The two main findings presented in this paper are that the entropy conserving flux of Ismail & Roe can easily break down for certain initial conditions commonly found in astrophysical simulations, and that special care must be taken in the derivation of a discrete dissipation matrix for an entropy stable numerical scheme to be robust. We present a convenient novel averaging procedure to evaluate the entropy Jacobians of the ideal MHD and the compressible Euler equations that yields a discretization with favorable robustness properties.

  15. The Generalised Dolbeault Complex for Four Dirac Operators in the Stable Rank

    NASA Astrophysics Data System (ADS)

    Krump, Lukáš

    2008-09-01

    The Hartog's type phenomena in several complex variables are best understood in term of the Dolbeault sequence. A lot of attention was paid in the last decades to its analogue in the function theory of several Clifford variables. The first operator in this resolution is the Dirac operator in several variables. The complete description is known in dimension 4. Much less is known in higher dimensions. The case of three variables was described completely by F. Colombo, I. Sabadini, F. Sommen, D. C. Struppa. The full description of the complex for all dimensions is not known at present. Even the case of the stable range (i.e., when the number of variables is less or equal to the half of dimension) is still not fully understood. In the paper, we construct the resolution for the case of four variables in the stable range. The main tool used in the construction is the Penrose transform.

  16. Stable, high-performance operation of a fiber-coupled superconducting nanowire avalanche photon detector

    NASA Astrophysics Data System (ADS)

    Miki, Shigehito; Yabuno, Masahiro; Yamashita, Taro; Terai, Hirotaka

    2017-03-01

    We present a stable and high-performance fiber-coupled NbTiN superconducting nanowire avalanche photon detector (SNAP). We demonstrate afterpulse-free operation in serially connected two SNAPs (SC-2SNAP), even in the absence of a choke inductor, achieving a 7.7 times faster response speed than standard SSPDs. The SC-2SNAP device showed a system detection efficiency (SDE) of 81.0% with wide bias current margin, a dark count rate of 6.8 counts/s, and full width at half maximum timing jitter of 68 ps, operating at 2.3 K.

  17. Stable Artificial Dissipation Operators for Finite Volume Schemes on Unstructured Grids

    NASA Technical Reports Server (NTRS)

    Svard, Magnus; Gong, Jing; Nordstrom, Jan

    2006-01-01

    Our objective is to derive stable first-, second- and fourth-order artificial dissipation operators for node based finite volume schemes. Of particular interest are general unstructured grids where the strength of the finite volume method is fully utilized. A commonly used finite volume approximation of the Laplacian will be the basis in the construction of the artificial dissipation. Both a homogeneous dissipation acting in all directions with equal strength and a modification that allows different amount of dissipation in different directions are derived. Stability and accuracy of the new operators are proved and the theoretical results are supported by numerical computations.

  18. 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.

  19. Remotely operated compact underwater temporally encoded imager: CUTEI

    NASA Astrophysics Data System (ADS)

    Alley, Derek; Cochenour, Brandon; Mullen, Linda

    2016-05-01

    Remotely operated vehicles (ROVs) typically use traditional optical imaging systems, such as cameras, for high resolution imaging. Cameras are effective in clear water, but have extremely poor performance in degraded visual environments (DVEs) such as turbid coastal waters and harbors. This is due to the multiple scattering of the light from the particulates and organic matter in the water. Laser-based sensors have been developed to enhance optical imaging in DVEs1,3,4,5,6. However, since conventional approaches require that the illuminator and receiver be located on the same platform, the size, weight, and power (SWaP) requirements are incompatible with small ROVs. Researchers at NAVAIR have developed a low cost optical imager utilizing a bistatic geometry where the illuminator and receiver are mounted on separate, smaller platforms. The illuminator steers a modulated laser beam with a microelectromechanical system (MEMS) scanner to sequentially illuminate an underwater object. A distant receiver collects the object reflected laser light and reconstructs the imagery. Communications information, including a synchronization sequence, is encoded onto the modulation which is used by the receiver to build the image. The SWaP of the illuminator's components have been optimized and integrated into a modified version of the OpenROV, a miniature, commercial off-the-shelf ROV. This paper reports on the efforts to reduce the SWaP of the modulated illuminator and the results of testing this system in a laboratory water tank environment.

  20. Spatial distribution and temporal variability of stable water isotopes in a large and shallow lake.

    PubMed

    Xiao, Wei; Wen, Xuefa; Wang, Wei; Xiao, Qitao; Xu, Jingzheng; Cao, Chang; Xu, Jiaping; Hu, Cheng; Shen, Jing; Liu, Shoudong; Lee, Xuhui

    2016-01-01

    Stable isotopic compositions of lake water provide additional information on hydrological, meteorological and paleoclimate processes. In this study, lake water isotopic compositions were measured for more than three years in Lake Taihu, a large and shallow lake in southern China, to investigate the isotopic spatial and seasonal variations. The results indicated that (1) the whole-lake mean δ(2)H and δ(18)O values of the lake water varied seasonally from -48.4 ± 5.8 to -25.1 ± 3.2 ‰ and from -6.5 ± 0.9 to -3.5 ± 0.8 ‰, respectively, (2) the spatial pattern of the lake water isotopic compositions was controlled by the direction of water flow and not by local evaporation rate, and (3) using a one-site isotopic measurement to represent the whole-lake mean may result in unreasonable estimates of the isotopic composition of lake evaporation and the lake water residence time in poorly mixed lakes. The original data, documented here as an online supplement, provides a good reference for testing sensitivity of lake water budget to various isotopic sampling strategies. We propose that detailed spatial measurement of lake water isotopic compositions provides a good proxy for water movement and pollutant and alga transports, especially over big lakes.

  1. Spatial and temporal variability of stable isotopes and biological parameters for the Danube River in Serbia.

    PubMed

    Mitrovic, Tatjana; Obradovic, Vesna; Golobocanin, Dusan; Ogrinc, Nives; Miljevic, Nada

    2010-06-01

    This paper presents the results of hydrological, physicochemical, biological, and isotopic investigations of the Danube River along the stretch through Serbian territory conducted during four campaigns in September and November 2007, September 2008 and April 2009. The stable isotope values exhibited significant changes both in the Danube (-10.7 to-9.5 per thousand for delta(18)O and-73.7 to-67.1 per thousand for delta(2)H) and in its tributaries (-9.1 to-8.5 per thousand for delta(18)O and-69.4 to-59.4 per thousand for delta(2)H) depending on the time of survey, which could be partly attributed to the influences of seasonal effects. Results emphasise the dominant role of tributaries inflows from aquifers along the Danube. The very narrow range of delta(13)C(POC) (from-28.9 to-27.4 per thousand) was associated with relatively high C/N ratios (C/N>9), and together with delta(15)N(TPN) values, the date suggested that, in early spring, a major fraction of particulate organic matter was derived from allochthonous matter. An orthogonal varimax rotation of the principal components analysis identified four latent factors ('mineral related', 'biological', 'hardness', and 'soil inlets') which are responsible for the data structure covering 79% of the observed variations among the variables studied. A reliable grouping of samples with respect to the season was found.

  2. Food web structure of sandy beaches: Temporal and spatial variation using stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Bergamino, Leandro; Lercari, Diego; Defeo, Omar

    2011-03-01

    The food web structure of two sandy beach ecosystems with contrasting morphodynamics (dissipative vs. reflective) was examined using stable carbon (δ 13C) and nitrogen (δ 15N) isotope analysis. Organic matter sources (POM: particulate organic matter; SOM: sediment organic matter) and consumers (zooplankton, benthic invertebrates and fishes) were sampled seasonally in both sandy beaches. Food webs significantly differed between beaches: even though both webs were mainly supported by POM, depleted δ 13C and δ 15N values for food sources and consumers were found in the dissipative system (following the reverse pattern in δ 13C values for consumers) for all the four seasons. Primary consumers (zooplankton and benthic invertebrates) use different organic matter sources on each beach and these differences are propagated up in the food web. The higher productivity found in the dissipative beach provided a significant amount of food for primary consumers, notably suspension feeders. Thus, the dissipative beach supported a more complex food web with more trophic links and a higher number of prey and top predators than the reflective beach. Morphodynamic factors could explain the contrasting differences in food web structure. The high degree of retention (nutrients and phytoplankton) recorded for the surf zone of the dissipative beach would result in the renewed accumulation of POM that sustains a more diverse and richer fauna than the reflective beach. Further studies directed to assess connections between the macroscopic food web, the surf-zone microbial loop and the interstitial compartment will provide a deeper understanding on the functioning of sandy beach ecosystems.

  3. Experimental evaluation of stable long term operation of semiconductor magnetic sensors at ITER relevant environment

    NASA Astrophysics Data System (ADS)

    Bolshakova, I.; Belyaev, S.; Bulavin, M.; Brudnyi, V.; Chekanov, V.; Coccorese, V.; Duran, I.; Gerasimov, S.; Holyaka, R.; Kargin, N.; Konopleva, R.; Kost, Ya.; Kuech, T.; Kulikov, S.; Makido, O.; Moreau, Ph; Murari, A.; Quercia, A.; Shurygin, F.; Strikhanov, M.; Timoshyn, S.; Vasil'evskii, I.; Vinichenko, A.

    2015-08-01

    The paper deals with radiation resistant sensors and their associated measuring instrumentation developed in the course of R and D activities carried out in the framework of an international collaboration. The first trial tests of three-dimensional (3D) probes with Hall sensors have been performed in European tokamaks TORE SUPRA (2004) and JET (2005). Later in 2009 six sets of 3D probes were installed in JET and now continue to operate. The statistical analysis performed in 2014 on the basis of the JET database have demonstrated stable long term operation of all 18 sensors of 3D probes. The results of measurements conducted at the neutron fluxes of nuclear reactors have demonstrated the operability of the sensors up to high neutron fluences of F  >  1018n • cm-2 that exceeds the maximum one for the locations of steady state sensors in ITER over its total lifetime.

  4. 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.

  5. 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.

  6. High voltage threshold for stable operation in a dc electron gun

    SciTech Connect

    Yamamoto, Masahiro; Nishimori, Nobuyuki

    2016-07-04

    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 model 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.

  7. Exactness of the generalized Dolbeault complex for k Dirac operators in the stable rank

    NASA Astrophysics Data System (ADS)

    Krump, Lukáš; Salač, Tomáš

    2012-09-01

    The Hartog's type phenomena in several complex variables are best understood in terms of the Dolbeault sequence. A lot of attention was paid in the last decades to its analogue in the function theory of several Clifford variables, i.e. the Dirac operator in several variables. A so-called BGG resolution of this operator is then an analogue to the Dolbeault sequence. The complete description is known in dimension 4. Much less is known in higher dimensions. The case of three variables was described completely by F. Colombo, I. Sabadini, F. Sommen, D. C. Struppa. The full description of the complex for all dimensions is not known at present. In the case of the stable rank (i.e., when the number of variables is less or equal to the half of the even dimension), certain progress has been done. In the paper, we construct the resolution for the case of k variables in the stable range, we show the case of k = 4 in details, and we show the exactness of this sequence. The tools used in the construction are the Penrose transform, Čech cohomology and Leray theorem.

  8. Nuclear DNA synthesis in vitro is mediated via stable replication forks assembled in a temporally specific fashion in vivo

    SciTech Connect

    Heintz, N.H.; Stillman, B.W.

    1988-05-01

    A cell-free nuclear replication system that is S-phase specific, that requires the activity of DNA polymerase alpha, and that is stimulated three- to eightfold by cytoplasmic factors from S-phase cells was used to examine the temporal specificity of chromosomal DNA synthesis in vitro. Temporal specificity of DNA synthesis in isolated nuclei was assessed directly by examining the replication of restriction fragments derived from the amplified 200-kilobase dihydrofolate reductase domain of methotrexate-resistant CHOC 400 cells as a function of the cell cycle. In nuclei prepared from cells collected at the G1/S boundary of the cell cycle, synthesis of amplified sequences commenced within the immediate dihydrofolate reductase origin region and elongation continued for 60 to 80 min. The order of synthesis of amplified restriction fragments in nuclei from early S-phase cells in vitro appeared to be indistinguishable from that in vivo. Nuclei prepared from CHOC 400 cells poised at later times in the S phase synthesized characteristic subsets of other amplified fragments. The specificity of fragment labeling patterns was stable to short-term storage at 4/sup 0/C. The occurrence of stimulatory factors in cytosol extracts was cell cycle dependent in that minimal stimulation was observed with early G1-phase extracts, whereas maximal stimulation was observed with cytosol extracts from S-phase cells. Chromosomal synthesis was not observed in nuclei from G1 cells, nor did cytosol extracts from S-phase cells induce chromosomal replication in G1 nuclei. In contrast to chromosomal DNA synthesis, mitochondrial DNA replication in vitro was not stimulated by cytoplasmic factors and occurred at equivalent rates throughout the G1 and S phases.

  9. Knowledge engineering for temporal dependency networks as operations procedures. [in space communication

    NASA Technical Reports Server (NTRS)

    Fayyad, Kristina E.; Hill, Randall W., Jr.; Wyatt, E. J.

    1993-01-01

    This paper presents a case study of the knowledge engineering process employed to support the Link Monitor and Control Operator Assistant (LMCOA). The LMCOA is a prototype system which automates the configuration, calibration, test, and operation (referred to as precalibration) of the communications, data processing, metric data, antenna, and other equipment used to support space-ground communications with deep space spacecraft in NASA's Deep Space Network (DSN). The primary knowledge base in the LMCOA is the Temporal Dependency Network (TDN), a directed graph which provides a procedural representation of the precalibration operation. The TDN incorporates precedence, temporal, and state constraints and uses several supporting knowledge bases and data bases. The paper provides a brief background on the DSN, and describes the evolution of the TDN and supporting knowledge bases, the process used for knowledge engineering, and an analysis of the successes and problems of the knowledge engineering effort.

  10. Functional connectivity MRI and post-operative language performance in temporal lobe epilepsy: initial experience.

    PubMed

    Pravatà, Emanuele; Sestieri, Carlo; Colicchio, Gabriella; Colosimo, Cesare; Romani, Gian Luca; Caulo, Massimo

    2014-04-01

    Anterior temporal lobectomy is an effective treatment for drug-resistant epilepsy of temporal origin, although new language impairment may develop after surgery. Since correlations between functional connectivity (FC) MRI of the language network and verbal-IQ performance before surgery have recently been reported, we investigated the existence of correlations between the preoperative FC of the language network and post-operative verbal-IQ decline. FC between nodes of the language network of the two hemispheres (Interhemispheric-FC) and within nodes of the left hemisphere (LH-FC) and language lateralization indexes were estimated in five right-handed patients with non-tumoral left temporal lobe epilepsy undergoing anterior temporal lobectomy. Correlations between preoperative FC measures and lateralization indexes, and the post-operative (12 months) neuropsychological verbal-IQ decline were investigated. Verbal-IQ decline was inversely correlated with the degree of left lateralization and directly correlated with the strength of Interhemispheric-FC. No significant correlation was found between LH-FC and post-operative verbal-IQ change. The results from this limited number of patients suggest that a stronger preoperative connectivity between homologue regions, associated with the absence of a definite hemispheric lateralization, appears to be an unfavorable prognostic biomarker.

  11. Improvements in mixing operations of water treatment plants by use of a stable finite element model.

    PubMed

    Vellando, P; Fe, J; Juncosa, R; Padilla, F

    2007-06-01

    This work shows improvements made in mixing operations at water treatment plants, as a result of the hydrodynamic analysis of the mixing processes carried out by the use of a Finite Element Model. The code, developed in the Civil Engineering Department of the University of La Coruña, Spain, solves the Navier-Stokes equations that rule viscous incompressible flow by using a Streamline Upwind/Petrov-Galerkin (SUPG) stabilization technique. The incorporation of the SUPG formulation leads to obtaining stable solutions for Reynolds numbers of a moderate order in connection with meshes that are not very refined. Some water treatment units present significant deficiencies in their design. The numerical evaluation of the flow avoids the high expenses of the trial-and-error processes involved in installing and removing the mixing mechanisms and those derived from the need to halt the water treatment processes. As a result, an optimum design of the treatment plant is obtained at a low cost.

  12. Stable Operation of the 2 K Cryogenic System for the Superconducting Accelerator at Peking University

    NASA Astrophysics Data System (ADS)

    Lin, Lin; Hao, Jian-Kui; Xie, Hua-Mu; Quan, Sheng-Wen; Wen, Xiao-Dong; Zhao, Kui; Liu, Ke-Xin

    2013-08-01

    A superconducting energy recovery linac test facility (PKU-SETF) was built at Peking University, and a 2K cryogenic system, which is the first closed-loop 2K cryogenic system for a superconducting accelerator in China, was constructed for the 1.3 GHz 3+1/2 cell dc-SRF injector. The main accelerator consists of two nine-cell TESLA-type superconducting cavities of the PKU-SETF The commissioning and stable operation of this 2 K cryogenic system was carried out. A helium pressure stability of better than ±0.1 mbar and a total refrigeration capacity of 65 W at a temperature of 2K was reached.

  13. 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.

  14. On upscaling operator-stable Levy motions in fractal porous media

    SciTech Connect

    Park, Moongyu; Cushman, John H. . E-mail: jcushman@purdue.edu

    2006-09-01

    The dynamics of motile particles, such as microbes, in random porous media are modeled with a hierarchical set of stochastic differential equations which correspond to micro, meso and macro scales. On the microscale the motile particle is modeled as an operator stable Levy process with stationary, ergodic, Markov drift. The micro to meso and meso to macro scale homogenization is handled with generalized central limit theorems. On the mesoscale the Lagrangian drift (or the Lagrangian acceleration) is assumed Levy to account for the fractal character of many natural porous systems. Diffusion on the mesoscale is a result of the microscale asymptotics while diffusion on the macroscale results from the mesoscale asymptotics. Renormalized Fokker-Planck equations with time dependent dispersion tensors and fractional derivatives are presented at the macro scale.

  15. 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.

  16. 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

  17. Photonic temporal integration of broadband intensity waveforms over long operation time windows.

    PubMed

    Asghari, Mohammad H; Park, Yongwoo; Azaña, José

    2011-09-15

    We propose and experimentally demonstrate a novel design for temporal integration of microwave and optical intensity waveforms with combined high processing speed and a long operation time window. It is based on concatenating in series a discrete-time (low-speed) photonic integrator and a high-speed analog time-limited intensity integrator. This scheme is demonstrated here using a cascaded fiber-based interferometers' system (as a passive eight-point discrete-time integrator) and an analog time-limited intensity integrator. The latter is based on temporal intensity modulation of the input waveform with a rectangular-like incoherent energy spectrum followed by linear dispersion. Using this setup, we experimentally achieve accurate time integration of intensity signals with ~36 GHz bandwidths over an operation time window of ~4 ns, corresponding to a processing time-bandwidth product of >144.

  18. Stable, high-performance operation of a fiber-coupled superconducting nanowire avalanche photon detector.

    PubMed

    Miki, Shigehito; Yabuno, Masahiro; Yamashita, Taro; Terai, Hirotaka

    2017-03-20

    Recent progress in the development of superconducting nanowire single photon detectors (SSPD or SNSPD) has delivered excellent performance, and has had a great impact on a range of research fields. Significant efforts are being made to further improve the technology, and a primary concern remains to resolve the trade-offs between detection efficiency (DE), timing jitter, and response speed. We present a stable and high-performance fiber-coupled niobium titanium nitride superconducting nanowire avalanche photon detector (SNAP) that resolves these trade-offs. Autocorrelation function measurement revealed an afterpulse-free operation in serially connected two SNAP (SC-2SNAP), even in the absence of a choke inductor, achieving a 7.65 times faster response speed than standard SSPDs. The SC-2SNAP device showed a system detection efficiency (SDE) of 81.0% with wide bias current margin, a dark count rate of 6.8 counts/s, and full width at half maximum timing jitter of 68 ps, operating in a practical Gifford-McMahon cryocooler system.

  19. Electro-nanomechanically wavelength-tunable integrated-optical Bragg reflectors Part II: Stable device operation

    NASA Astrophysics Data System (ADS)

    Gabathuler, W.; Lukosz, W.

    1998-01-01

    We demonstrate stable operation of electro-nanomechanically wavelength-tunable integrated-optical (IO) Bragg reflectors. We eliminated the wavelength drift of these IO devices reported in a previous paper I [Optics Comm. 135 (1997) 385] by surface treatment (hydrophobization) of the waveguides and of the micromachined membranes. The membranes are spanned as `effective-refractive-index-shifting elements' E over surface relief gratings on the planar or rib waveguides. Electrostatic forces cause elastic deflections of an element E and, consequently, changes in the width of a sub-wavelength-wide air gap between the element E and the waveguide. Thus, the effective-refractive-index changes required for device operation are induced. As the cause of the drift effect, we identified the small but finite ionic electric conductivity of the nanometer thick adsorbed water film on the surfaces of the element E and of the waveguide enclosing the air gap. The IO nanomechanical devices with response times of μs to ms are fabricated using silicon technology. Their achieved stability is a precondition for potential applications, for example, as wavelength-tunable filters in optical networks.

  20. 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

  1. Spatial and temporal migration patterns of Wilson's Warbler (Wilsonia pusilla) in the southwest as revealed by stable isotopes

    USGS Publications Warehouse

    Paxton, K.L.; van Riper, Charles; Theimer, T.C.; Paxton, E.H.

    2007-01-01

    We used stable hydrogen isotopes (??D) to identify the breeding locations of Wilson's Warbler (Wilsonia pusilla) migrating through five sites spanning a cross-section of the species' southwestern migration route during the springs of 2003 and 2004. Determining the temporal and spatial patterns of migration and degree of population segregation during migration is critical to understanding long-term population trends of migrant birds. At all five migration sites, we found a significant negative relationship between the date Wilson's Warblers passed through the sampling station and ??D values of their feathers. These data were consistent with a pattern of "leap-frog" migration, in which individuals that bred the previous season at southern latitudes migrated through migration stations earlier than individuals that had previously bred at more northern latitudes. We documented that this pattern was consistent across sites and in multiple years. This finding corroborates previous research conducted on Wilson's Warbler during the fall migration. In addition, mean ??D values became more negative across sampling stations from west to east, with the mean ??D values at each station corresponding to different geographic regions of the Wilson's Warblers' western breeding range. These data indicate that Wilson's Warblers passing through each station represented a specific regional subset of the entire Wilson's Warbler western breeding range. As a result, habitat alterations at specific areas across the east-west expanse of the bird's migratory route in the southwestern United States could differentially affect Wilson's Warblers at different breeding areas. This migration information is critical for management of Neotropical migrants, especially in light of the rapid changes presently occurring over the southwestern landscape. ?? The American Ornithologists' Union, 2007.

  2. Temporal and spatial variability of stable isotopes of the water molecule in the Ebro River basin, Spain

    NASA Astrophysics Data System (ADS)

    Negrel, Philippe; Petelet-Giraud, Emmanuelle; Millot, Romain

    2014-05-01

    Variations in the stable-isotope O and H composition in a catchment's water balance are mainly caused by natural variations in the isotopic composition of rainfall, through the mixing with pre-existing waters and the influence of evaporation. Stable isotopes of water can be considered as conservative and as not being affected by exchanges with soil or rock. Stable isotopes were analysed in the surface waters along the course of the Ebro River, in main tributaries of the Ebro river, in some groundwater, and over a one year survey at the outlet. The global meteoric-water line is used to represent the meteoric input as well as the local rainwater characteristics measured in five stations, all surrounding the Ebro catchment. Mean weighted rain input showed enriched values for four stations and a depleted one for the latter (large continental circulation of air masses). The δ18O and δ2H relationships for surface- and ground waters collected in the Ebro catchment with other rivers draining the French side of the Pyrenees or along the Mediterranean Sea are compiled. Most of the points clearly plot close to the global and local meteoric-water lines reflecting a meteoric origin and a lack of significant evaporation or oxygen isotopes exchanges between water and the rock matrix. The tributaries present large variations in their δ18O and δ2H signatures but only the Guadalope river has an evaporated signal.ghe most depleted values are observed for the tributaries draining the Pyrenees agreeing with the Cauterets and Garonne river signatures on the French side. The Aragon, also draining the Pyrenees, has a more enriched signature that agree with the one observed in the Adour river on the French side. However, all tributaries have more depleted values than all mean rain water signal on the Ebro catchment as given by the local rain monitoring stations. If the Burgos station is considered as representative of long range continental transport, the depleted values in the

  3. Imaging Modality of Choice for Pre-Operative Cochlear Imaging: HRCT vs. MRI Temporal Bone

    PubMed Central

    Solanki, Rajendra N.; Shah, Dipali C.; Vishwakarma, Rajesh; Kumar, Sandeep

    2016-01-01

    Introduction Congenital inner ear malformations occur as a result of the arrest or aberrance of inner ear development due to the heredity, gene mutation or other factors. Ever since the availability of cochlear implants, pre-operative evaluation by imaging of temporal bone has gained much attention. Precise selection of the candidate for cochlear implant dependent on preoperative radiological investigations. Only CT (Computed Tomography) and MRI (Magnetic Resonance Imaging) can provide a better picture of anatomy and pathology. Aim To compare pre-operative imaging findings of both MRI and High Resolution Computed Tomography (HRCT) temporal bone and to find the best modality of choice in patients with bilateral profound Sensorineural Hearing Loss (SNHL). Materials and Methods This was a prospective, longitudinal, observational study conducted between June 2010 to November 2012. A total of 144 temporal bones were evaluated in 72 children with bilateral profound SNHL with congenital inner ear malformations. Each temporal bone was considered as a single case (144 cases). All the patients underwent HRCT and high field MRI study. MRI study included T2 W axial 3D FIESTA (Fast Imaging Employing Steady-state Acquisition) sequence. Anatomic abnormalities in each temporal bone were described and noted. For complete and better evaluation of Vestibulo-Cochlear Nerve (VCN) additional 3D oblique parasagittal view was taken perpendicular to the internal auditory canal with a small Field Of View (FOV). Results HRCT and MRI allowed accurate detection of inner ear malformations in children with bilateral SNHL. Majority of the patients presented with multiple structural abnormalities of inner ear. The common pathologies detected in the study were semicircular canal abnormality (89/144) followed by cochlear abnormalities (39/144). Most common cochlear abnormality was Mondini’s deformity (14/144). MRI demonstrated absent of vestibulo-cochlear nerve in 15 cases. Conclusion Few

  4. 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.

  5. 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.…

  6. 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.…

  7. 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

  8. Temperature range and conditions of stable operation of gas-discharge rare-earth metal vapor lasers

    NASA Astrophysics Data System (ADS)

    Gerasimov, V. A.; Gerasimov, V. V.; Pavlinskiy, A. V.

    2008-08-01

    We have experimentally studied the temperature range and conditions of the stable operation of rare-earth metal (REM) vapor lasers. Gas-discharge tubes made of alumina (Al2O3-GDTs) were used in the experiments. The lasing appears at the temperature when the saturated-vapor pressure of REMs reaches the value of 0.1 Torr and abruptly drops at the melting temperature of corresponding REM under any excitation conditions. The necessity of protecting film of REM aluminates LnnAlmOk and oxides Ln2O3 on the inner surface of Al2O3-GDT for stable operation of these lasers is shown. An explanation of lasing impossibility in vapors of cerium (Ce), praseodymium (Pr), neodymium (Nd), gadolinium (Gd), and terbium (Tb) under gas-discharge excitation is proposed.

  9. Data-driven spatio-temporal RGBD feature encoding for action recognition in operating rooms.

    PubMed

    Twinanda, Andru P; Alkan, Emre O; Gangi, Afshin; de Mathelin, Michel; Padoy, Nicolas

    2015-06-01

    Context-aware systems for the operating room (OR) provide the possibility to significantly improve surgical workflow through various applications such as efficient OR scheduling, context-sensitive user interfaces, and automatic transcription of medical procedures. Being an essential element of such a system, surgical action recognition is thus an important research area. In this paper, we tackle the problem of classifying surgical actions from video clips that capture the activities taking place in the OR. We acquire recordings using a multi-view RGBD camera system mounted on the ceiling of a hybrid OR dedicated to X-ray-based procedures and annotate clips of the recordings with the corresponding actions. To recognize the surgical actions from the video clips, we use a classification pipeline based on the bag-of-words (BoW) approach. We propose a novel feature encoding method that extends the classical BoW approach. Instead of using the typical rigid grid layout to divide the space of the feature locations, we propose to learn the layout from the actual 4D spatio-temporal locations of the visual features. This results in a data-driven and non-rigid layout which retains more spatio-temporal information compared to the rigid counterpart. We classify multi-view video clips from a new dataset generated from 11-day recordings of real operations. This dataset is composed of 1734 video clips of 15 actions. These include generic actions (e.g., moving patient to the OR bed) and actions specific to the vertebroplasty procedure (e.g., hammering). The experiments show that the proposed non-rigid feature encoding method performs better than the rigid encoding one. The classifier's accuracy is increased by over 4 %, from 81.08 to 85.53 %. The combination of both intensity and depth information from the RGBD data provides more discriminative power in carrying out the surgical action recognition task as compared to using either one of them alone. Furthermore, the proposed non

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

    DTIC Science & Technology

    2007-11-01

    quickly become saturated with the noble buffer gas , the turbo pump provides a much longer operating life and provides a stable pumping speed. Sealed...of potential drift contributors in the LITS showed that the leading candidates are fluctuations in background gases and the neon buffer gas . The...which does not pump inert gases such as the current neon buffer gas . With a fixed quantity of buffer gas , a getter pump could provide decades of

  11. Precipitation stable isotope analysis for exploring temporal characteristics of tropical cyclones: A case study in Hong Kong

    NASA Astrophysics Data System (ADS)

    Chun, K. P.; Klaus, J.

    2016-12-01

    Hurricanes (or typhoons) play an important role in tropical and subtropical synoptic climates. Although increasing global temperatures in the 20th and 21st centuries are proposed to be linked to changing characteristics of hurricanes, results from previous studies are contradictory and changing environmental conditions affecting hurricanes are somewhat poorly conceptualised. In this investigation, stable precipitation isotope data are used to explore how hurricane properties change with variations of monsoon and regional climate patterns (e.g. the El Niño-Southern Oscillations). As a case study, a new approach using precipitation isotopes to analyse Hong Kong tropical cyclone time series is proposed. First, the variance of precipitation stable isotopes is decomposed to understand the influence of monsoons, southern oscillations and other regional climate conditions on Hong Kong precipitation isotopic signatures. Then, using decomposed precipitation isotope results, a frequency analysis of tropical hurricanes is performed to identify climatic controls and quantify their effects. Results from this study are expected to be valuable because they will provide an example which illustrates how local isotope data can be linked to the regional climate patterns. A framework to investigate Asian tropical cyclone change using stable precipitation isotopes is also proposed.

  12. 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

  13. 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.

  14. Elastomeric Microchip Electrospray Emitter for Stable Cone-Jet Mode Operation in the Nanoflow Regime.

    SciTech Connect

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

    2008-05-15

    Despite widespread interest in applying lab-on-a-chip technologies to 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 in the Taylor cone of the 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 small Taylor cones at the channel exit ensures sub-nL post-column dead volumes. While comparable ESI-MS sensitivities were achieved using both microchip and conventional fused silica capillary emitters, stable cone-jet mode electrospray could be established over a far broader range of flow rates (from 50–1000 nL/min) and applied potentials using the microchip emitters. This special feature of the microchip emitter should minimize the fine tuning required for electrospray optimization and make the stable electrospray more resistant to external perturbations.

  15. Tracing geographic and temporal trafficking patterns for marijuana in Alaska using stable isotopes (C, N, O and H).

    PubMed

    Booth, Amanda L; Wooller, Matthew J; Howe, Timothy; Haubenstock, Norma

    2010-10-10

    A large proportion of Alaska Bureau of Alcohol and Drug Enforcement's time is spent controlling the production and distribution of marijuana. Marijuana in Alaska can originate from within (e.g., Fairbanks and the Matanuska-Susitna Valley) or from outside Alaska (e.g., Latin America, Canada and other locations in the United States of America). However it is difficult to track the supply proportions from various potential geographic areas in remote areas of the globe, such as Alaska. This is due to an insufficient ability to trace the source regions from which confiscated marijuana was originally grown. We analyzed multiple stable isotopes (C, N, O and H) in marijuana confiscated in Alaska, to identify the likely geographic source from which the marijuana originated. Fifty-six of the marijuana samples were from known grow locations in Alaska. These samples exhibited stable oxygen and hydrogen isotope ratios (δ(18)O and δD) of 10.4‰ to 37.0‰ and -203.1‰ to -136.7‰, respectively. Stable carbon and nitrogen isotope ratios (δ(13)C and δ(15)N) of the same samples ranged from -53.8‰ to -26.4‰ and -12.5‰ to 12.1‰, respectively. We use these data to compare with stable isotope analyses of marijuana confiscated in Alaska, but from unknown grow locations, which were found to have δ(18)O and δD ranging from 10.0‰ to 34.5‰ and -214.6‰ to -107.5‰, respectively. The large range of data suggests that the samples originated from multiple sources ranging from low to high latitudes. A large range in δ(15)N values from the samples was also evident (-5.0‰ to 14.7‰). Most intriguing of all was the unexpected large range in the stable carbon isotope compositions of the samples (-61.8‰ to -24.6‰). Twelve of the samples were found to have an exceedingly low δ(13)C values (-36.1‰ to -61.8‰) compared to typical δ(13)C values of other plants using C3 photosynthesis. Interior growing conditions (e.g., hydroponic and green house) and a variety of CO(2

  16. A uniquely defined entropy stable matrix dissipation operator for high Mach number ideal MHD and compressible Euler simulations

    NASA Astrophysics Data System (ADS)

    Winters, Andrew R.; Derigs, Dominik; Gassner, Gregor J.; Walch, Stefanie

    2017-03-01

    We describe a unique averaging procedure to design an entropy stable dissipation operator for the ideal magnetohydrodynamic (MHD) and compressible Euler equations. Often in the derivation of an entropy conservative numerical flux function much care is taken in the design and averaging of the entropy conservative numerical flux. We demonstrate in this work that if the discrete dissipation operator is not carefully chosen as well it can have deleterious effects on the numerical approximation. This is particularly true for very strong shocks or high Mach number flows present, for example, in astrophysical simulations. We present the underlying technique of how to construct a unique averaging technique for the discrete dissipation operator. We also demonstrate numerically the increased robustness of the approximation.

  17. Raceway control with oxygen, steam and coal for stable blast furnace operation

    SciTech Connect

    Chatterjee, L.M.

    1996-12-31

    Tata Steel operates seven blast furnaces at its Jamshedpur works. Coal injection was introduced in the three larger furnaces starting in 1991, and coal tar injection was commissioned in the A blast furnace in June, 1996. Presently, a coal injection level of 130 kg/thm has been achieved at G blast furnace, which is the newest and the largest among all blast furnaces at Tata Steel. The paper discusses the operational features of the blast furnaces at Tata Steel, practical limits of fuel injection, the philosophy of the control of raceway conditions, and experience with fuel injection at Tata Steel.

  18. 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.

  19. 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

  20. [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.

  1. Characterization of 4 years MagnetoTelluric monitoring data by studying the temporal behaviour of Alpha Stable Distribution Parameters

    NASA Astrophysics Data System (ADS)

    Siniscalchi, Agata; Romano, Gerardo; Barracano, Fabio; Balasco, Marianna; Tripaldi, Simona

    2017-04-01

    Analyzing a 4 years of a single site MT continuous monitoring data, a systematic variation of the MT transfer function estimates was observed in the [20-100 s] period range that was shown to be connected to the global geomagnetic activity, Ap index (Romano et al., 2014). The monitored period, from 2007 to 2011, includes the global minimum of solar activity which occurred in 2009 (low MT source amplitude). It was shown that the impedance robust estimations tend to stabilize when the Ap index exceed a value of 10. In order to exclude a possible dependence of the observed fluctuation on the presence of a local cultural noise source, for a shorter period ( 2 months) the monitoring data were also processed by using a remote site. Recently Chave (2012) demonstrated that MT data can be described by alpha stable distribution family that is characterized by four-parameters that must be empirically determined. The Gaussian distribution belongs to this family as a special case when one of the four parameter, α the tail thickness, is equal to 2. Following Chave (2016), MT data are typically stably distributed with the empirical observation that 0.8 ≤α ≤1.8. In order to better understand the observed dependence of the MT continuous monitoring on the global geomagnetic activity, here we present the results a re-analysis of the MT monitoring data with a two steps processing. In the first step, we characterize the time series of the Alpha Stable Distribution Parameters (ASDP) as obtained from the whole processing of the dataset with the aim of checking for possible connections between these last and the Ap index. In the second step, we estimate the ASDP by using only the samples which satisfy the mathematical range of existence of the normalized WAL (Weaver et al.,2000) considering these last as a diagnostic tool to detect which segments of the time series in the frequency domain are strongly contaminated by noise (WAL selection criterion). The comparison between the results

  2. The contribution of thermophilic anaerobic digestion to the stable operation of wastewater sludge treatment.

    PubMed

    Zábranská, J; Dohányos, M; Jenícek, P; Zaplatílková, P; Kutil, J

    2002-01-01

    Thermophilic anaerobic digestion of sewage sludge has been successfully operated in full-scale tanks almost three years. The higher loading capacity and specific biogas production rate in comparison with mesophilic digestion was proved. Thermophilic anaerobic sludge is also more resistant against foaming problems. Biogas from thermophilic tanks contains less hydrogen sulphide and other malodorous substances. Pathogens removal rate is apparently more efficient in the thermophilic process.

  3. Design optimization of MR-compatible rotating anode x-ray tubes for stable operation

    SciTech Connect

    Shin, Mihye; Lillaney, Prasheel; Hinshaw, Waldo; Fahrig, Rebecca

    2013-11-15

    Purpose: Hybrid x-ray/MR systems can enhance the diagnosis and treatment of endovascular, cardiac, and neurologic disorders by using the complementary advantages of both modalities for image guidance during interventional procedures. Conventional rotating anode x-ray tubes fail near an MR imaging system, since MR fringe fields create eddy currents in the metal rotor which cause a reduction in the rotation speed of the x-ray tube motor. A new x-ray tube motor prototype has been designed and built to be operated close to a magnet. To ensure the stability and safety of the motor operation, dynamic characteristics must be analyzed to identify possible modes of mechanical failure. In this study a 3D finite element method (FEM) model was developed in order to explore possible modifications, and to optimize the motor design. The FEM provides a valuable tool that permits testing and evaluation using numerical simulation instead of building multiple prototypes.Methods: Two experimental approaches were used to measure resonance characteristics: the first obtained the angular speed curves of the x-ray tube motor employing an angle encoder; the second measured the power spectrum using a spectrum analyzer, in which the large amplitude of peaks indicates large vibrations. An estimate of the bearing stiffness is required to generate an accurate FEM model of motor operation. This stiffness depends on both the bearing geometry and adjacent structures (e.g., the number of balls, clearances, preload, etc.) in an assembly, and is therefore unknown. This parameter was set by matching the FEM results to measurements carried out with the anode attached to the motor, and verified by comparing FEM predictions and measurements with the anode removed. The validated FEM model was then used to sweep through design parameters [bearing stiffness (1×10{sup 5}–5×10{sup 7} N/m), shaft diameter (0.372–0.625 in.), rotor diameter (2.4–2.9 in.), and total length of motor (5.66–7.36 in.)] to

  4. Design optimization of MR-compatible rotating anode x-ray tubes for stable operation

    PubMed Central

    Shin, Mihye; Lillaney, Prasheel; Hinshaw, Waldo; Fahrig, Rebecca

    2013-01-01

    Purpose: Hybrid x-ray/MR systems can enhance the diagnosis and treatment of endovascular, cardiac, and neurologic disorders by using the complementary advantages of both modalities for image guidance during interventional procedures. Conventional rotating anode x-ray tubes fail near an MR imaging system, since MR fringe fields create eddy currents in the metal rotor which cause a reduction in the rotation speed of the x-ray tube motor. A new x-ray tube motor prototype has been designed and built to be operated close to a magnet. To ensure the stability and safety of the motor operation, dynamic characteristics must be analyzed to identify possible modes of mechanical failure. In this study a 3D finite element method (FEM) model was developed in order to explore possible modifications, and to optimize the motor design. The FEM provides a valuable tool that permits testing and evaluation using numerical simulation instead of building multiple prototypes. Methods: Two experimental approaches were used to measure resonance characteristics: the first obtained the angular speed curves of the x-ray tube motor employing an angle encoder; the second measured the power spectrum using a spectrum analyzer, in which the large amplitude of peaks indicates large vibrations. An estimate of the bearing stiffness is required to generate an accurate FEM model of motor operation. This stiffness depends on both the bearing geometry and adjacent structures (e.g., the number of balls, clearances, preload, etc.) in an assembly, and is therefore unknown. This parameter was set by matching the FEM results to measurements carried out with the anode attached to the motor, and verified by comparing FEM predictions and measurements with the anode removed. The validated FEM model was then used to sweep through design parameters [bearing stiffness (1×105–5×107 N/m), shaft diameter (0.372–0.625 in.), rotor diameter (2.4–2.9 in.), and total length of motor (5.66–7.36 in.)] to increase the

  5. Frequency characteristics of an inherently stable Nd:YAG laser operated at liquid helium temperature

    SciTech Connect

    Scholz, Matthias; Kovalchuk, Evgeny; Peters, Achim

    2009-07-10

    We report on frequency measurements of a free-running Nd:YAG laser operating at temperatures down to 6.5 K using a femtosecond laser frequency comb. Due to lower thermal expansion and thermo-optic effects as well as reduced electron-phonon interactions in Nd:YAG at cryogenic temperatures, a laser frequency stability on the order of 10{sup -11} at {tau} < or = 30s has been achieved. Within a one-week measurement period, absolute frequency deviations were lower than 1.85 MHz. This is up to a 100-fold improvement of frequency stability compared to any existing free-running solid-state laser.

  6. RF-driven tokamak reactor with sub-ignited, thermally stable operation

    SciTech Connect

    Harten, L.P.; Bers, A.; Fuchs, V.; Shoucri, M.M.

    1981-02-01

    A Radio-Frequency Driven Tokamak Reactor (RFDTR) can use RF-power, programmed by a delayed temperature measurement, to thermally stabilize a power equilibrium below ignition, and to drive a steady state current. We propose the parameters for such a device generating approx. = 1600 MW thermal power and operating with Q approx. = 40 (= power out/power in). A one temperature zero-dimensional model allows simple analytical formulation of the problem. The relevance of injected impurities for locating the equilibrium is discussed. We present the results of a one-dimensional (radial) code which includes the deposition of the supplementary power, and compare with our zero-dimensional model.

  7. 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.; Prokop, Norman F.

    2008-01-01

    The fabrication and testing of the first semiconductor transistors and small-scale integrated circuits (ICs) to achieve up to 3000 h of stable electrical operation at 500 C in air ambient is reported. These devices are based on an epitaxial 6H-SiC junction field-effect transistor process that successfully integrated high temperature ohmic contacts, dielectric passivation, and ceramic packaging. Important device and circuit parameters exhibited less than 10% of change over the course of the 500 C operational testing. These results establish a new technology foundation for realizing durable 500 C ICs for combustion-engine sensing and control, deep-well drilling, and other harsh-environment applications.

  8. Stable and efficient operation of a large-bore copper vapor laser with funnel-shaped, grooved copper electrodes

    NASA Astrophysics Data System (ADS)

    Sadighi-Bonabi, R.; Pasandideh, K.; Zand, M.; Nazari Mahroo, H.

    2017-03-01

    Using an appropriate design of electrodes and adjustment of the thyratron decoupling circuit as a high-repetition-rate and high-voltage switch, very stable operation of a copper vapor laser at high pressures was obtained. This was achieved by canceling the intense filamentation in the laser plasma at the higher pressures. The transverse grooves on the inner surface of the funnel-shaped copper electrodes permit operation of the laser up to 100 torr. This design reduces the cathode-fall voltage, and as a result reduces the thermal loading in the cathode-fall region. The optimum pressure was 80 torr. At this condition the output power was more than that observed with expensive molybdenum electrodes in a similar laser system.

  9. Nonlinear dynamics analysis of a membrane Stirling engine: Starting and stable operation

    NASA Astrophysics Data System (ADS)

    Formosa, Fabien

    2009-10-01

    This paper presents the work devoted to the study of the operation of a miniaturized membrane Stirling engine. Indeed, such an engine relies on the dynamic coupling of the motion of two membranes to achieve a prime mover Stirling thermodynamic cycle. The modelling of the system introduces the large vibration amplitudes of the membrane as well as the nonlinear dissipative effects associated to the fluid flow within the engine. The nonlinearities are expressed as polynomial functions with quadratic and cubic terms. This paper displays the stability analysis to predict the starting of the engine and the instability problem which leads to the steady-state behaviour. The centre manifold-normal form theory is used to obtain the simplest expression for the limit cycle amplitudes. The approach allows the reduction of the number of equations of the original system in order to obtain a simplified system, without loosing the dynamics of the original system as well as the contributions of nonlinear terms. The model intends to be used as a semi-analytical design tool for the optimization of miniaturized Stirling machines from the starting to the steady operation.

  10. Spatial and temporal variability of compound-specific stable isotope (CSSI) biomarkers in soil and sediment tracing: towards improved sampling protocols

    NASA Astrophysics Data System (ADS)

    Reiffarth, Dominic; Petticrew, Ellen; Owens, Philip; Lobb, David

    2016-04-01

    The use of CSSI in biomarkers, specifically fatty acids and derivatives thereof, has recently been investigated as a potential tracer in soil and sediment fingerprinting. The use of CSSIs is of interest because of the potential to discern sediment providence based on land use, which is often difficult or not possible with other tracing techniques alone, such as geochemistry and fallout radionuclides. However, challenges exist in producing a representative sample of potential source materials. This presentation focuses on the development of improved protocols for sample collection. The data presented here are part of a larger investigation into using CSSIs as tracers in an agricultural watershed (South Tobacco Creek) in southern Manitoba, Canada. Extensive sampling was performed throughout the 2012 and 2013 growing seasons in several locations within the watershed, with a focus on capturing within and between field spatial and temporal variability in one particular sub-watershed (the "Stepler" watershed). The Stepler watershed provided a unique opportunity to perform sampling in a natural environment where agricultural crops were hydrologically separated, thereby allowing for a sampling regime of transects strategically placed with little influence from nearby crops. A portion of the data which has been analyzed, showing temporal and spatial variability in terms of carbon stable isotope signal, biomarker concentrations and soil organic carbon, is presented. As CSSI protocols for tracing are still in development, these data aid in determining the robustness of the technique as well as helping to inform sampling approaches.

  11. A path to stable low-torque plasma operation in ITER with test blanket modules

    NASA Astrophysics Data System (ADS)

    Lanctot, M. J.; Snipes, J. A.; Reimerdes, H.; Paz-Soldan, C.; Logan, N.; Hanson, J. M.; Buttery, R. J.; deGrassie, J. S.; Garofalo, A. M.; Gray, T. K.; Grierson, B. A.; King, J. D.; Kramer, G. J.; La Haye, R. J.; Pace, D. C.; Park, J.-K.; Salmi, A.; Shiraki, D.; Strait, E. J.; Solomon, W. M.; Tala, T.; Van Zeeland, M. A.

    2017-03-01

    New experiments in the low-torque ITER Q  =  10 scenario on DIII-D demonstrate that n  =  1 magnetic fields from a single row of ex-vessel control coils enable operation at ITER performance metrics in the presence of applied non-axisymmetric magnetic fields from a test blanket module (TBM) mock-up coil. With n  =  1 compensation, operation below the ITER-equivalent injected torque is successful at three times the ITER equivalent toroidal magnetic field ripple for a pair of TBMs in one equatorial port, whereas the uncompensated TBM field leads to rotation collapse, loss of H-mode and plasma current disruption. In companion experiments at high plasma beta, where the n  =  1 plasma response is enhanced, uncorrected TBM fields degrade energy confinement and the plasma angular momentum while increasing fast ion losses; however, disruptions are not routinely encountered owing to increased levels of injected neutral beam torque. In this regime, n  =  1 field compensation leads to recovery of a dominant fraction of the TBM-induced plasma pressure and rotation degradation, and an 80% reduction in the heat load to the first wall. These results show that the n  =  1 plasma response plays a dominant role in determining plasma stability, and that n  =  1 field compensation alone not only recovers most of the impact on plasma performance of the TBM, but also protects the first wall from potentially damaging heat flux. Despite these benefits, plasma rotation braking from the TBM fields cannot be fully recovered using standard error field control. Given the uncertainty in extrapolation of these results to the ITER configuration, it is prudent to design the TBMs with as low a ferromagnetic mass as possible without jeopardizing the TBM mission.

  12. A path to stable low-torque plasma operation in ITER with test blanket modules

    DOE PAGES

    Lanctot, Matthew J.; Snipes, J. A.; Reimerdes, H.; ...

    2016-12-12

    New experiments in the low-torque ITER Q = 10 scenario on DIII-D demonstrate that n = 1 magnetic fields from a single row of ex-vessel control coils enable operation at ITER performance metrics in the presence of applied non-axisymmetric magnetic fields from a test blanket module (TBM) mock-up coil. With n = 1 compensation, operation below the ITER-equivalent injected torque is successful at three times the ITER equivalent toroidal magnetic field ripple for a pair of TBMs in one equatorial port, whereas the uncompensated TBM field leads to rotation collapse, loss of H-mode and plasma current disruption. In companion experimentsmore » at high plasma beta, where the n = 1 plasma response is enhanced, uncorrected TBM fields degrade energy confinement and the plasma angular momentum while increasing fast ion losses; however, disruptions are not routinely encountered owing to increased levels of injected neutral beam torque. In this regime, n = 1 field compensation leads to recovery of a dominant fraction of the TBM-induced plasma pressure and rotation degradation, and an 80% reduction in the heat load to the first wall. These results show that the n = 1 plasma response plays a dominant role in determining plasma stability, and that n = 1 field compensation alone not only recovers most of the impact on plasma performance of the TBM, but also protects the first wall from potentially damaging heat flux. Despite these benefits, plasma rotation braking from the TBM fields cannot be fully recovered using standard error field control. Lastly, given the uncertainty in extrapolation of these results to the ITER configuration, it is prudent to design the TBMs with as low a ferromagnetic mass as possible without jeopardizing the TBM mission.« less

  13. A path to stable low-torque plasma operation in ITER with test blanket modules

    SciTech Connect

    Lanctot, Matthew J.; Snipes, J. A.; Reimerdes, H.; Paz-Soldan, C.; Logan, N.; Hanson, J. M.; Buttery, R. J.; deGrassie, J. S.; Garofalo, A. M.; Gray, T. K.; Grierson, B. A.; King, J. D.; Kramer, G. J.; La Haye, R. J.; Pace, D. C.; Park, J. -K.; Salmi, A.; Shiraki, D.; Strait, E. J.; Solomon, W. M.; Tala, T.; Van Zeeland, M. A.

    2016-12-12

    New experiments in the low-torque ITER Q = 10 scenario on DIII-D demonstrate that n = 1 magnetic fields from a single row of ex-vessel control coils enable operation at ITER performance metrics in the presence of applied non-axisymmetric magnetic fields from a test blanket module (TBM) mock-up coil. With n = 1 compensation, operation below the ITER-equivalent injected torque is successful at three times the ITER equivalent toroidal magnetic field ripple for a pair of TBMs in one equatorial port, whereas the uncompensated TBM field leads to rotation collapse, loss of H-mode and plasma current disruption. In companion experiments at high plasma beta, where the n = 1 plasma response is enhanced, uncorrected TBM fields degrade energy confinement and the plasma angular momentum while increasing fast ion losses; however, disruptions are not routinely encountered owing to increased levels of injected neutral beam torque. In this regime, n = 1 field compensation leads to recovery of a dominant fraction of the TBM-induced plasma pressure and rotation degradation, and an 80% reduction in the heat load to the first wall. These results show that the n = 1 plasma response plays a dominant role in determining plasma stability, and that n = 1 field compensation alone not only recovers most of the impact on plasma performance of the TBM, but also protects the first wall from potentially damaging heat flux. Despite these benefits, plasma rotation braking from the TBM fields cannot be fully recovered using standard error field control. Lastly, given the uncertainty in extrapolation of these results to the ITER configuration, it is prudent to design the TBMs with as low a ferromagnetic mass as possible without jeopardizing the TBM mission.

  14. Temporal changes in methane stable isotopes in polar ice cores: big picture and implications for ecosystem changes

    NASA Astrophysics Data System (ADS)

    Bock, Michael; Schmitt, Jochen; Seth, Barbara; Beck, Jonas; Fischer, Hubertus

    2014-05-01

    Methane (CH4) is the third most important greenhouse gas after water vapour and carbon dioxide (CO2). Since the industrial revolution the mixing ratio of CH4 in the atmosphere rose to ~1800 ppb, a value never reached within the last 800 000 years. Nowadays, CH4 contributes ~20% to the total radiative forcing from all of the long-lived greenhouse gases. This CH4 increase can only be assessed in relation to natural methane changes in the past. Firn air and air enclosures in polar ice cores represent the only direct paleoatmospheric archive. The latter show that atmospheric CH4 concentrations changed in concert with northern hemisphere temperature during both glacial/interglacial transitions as well as rapid climate changes (Dansgaard-Oeschger events), however, the sources of the methane concentration changes are still a matter of debate. Stable isotopes of methane (δ13CH4 and δD(CH4)) may help to distinguish differences in the magnitude of source type emissions (e.g. Bock et al. 2010). However, recently we could show that it is difficult to interpret the atmospheric loading of methane by relative source mix changes alone (Möller et al. 2013). In fact it appears, that the carbon isotopic signature (δ13CH4) of e.g. tropical wetlands undergoes drastic shifts connected to climate, CO2, sea level or potentially other unknown processes. Here we present the big picture derived from the EDML (European Project for Ice Coring in Antarctica, Dronning Maud Land) and Vostok ice cores (Möller et al. 2013) and additional new dual isotope data from 4 ice cores from both poles that cover three interglacials: the Holocene, MIS 5 and MIS 11. The contribution sheds light on our current understanding of methane biogeochemistry and discusses open questions. References: Bock, M., J. Schmitt, L. Möller, R. Spahni, T. Blunier, H. Fischer (2010). 'Hydrogen Isotopes Preclude Marine Hydrate CH4 Emissions at the Onset of Dansgaard-Oeschger Events', Science, 328, 1686-1689 Möller, L., T

  15. Temperature stable operation of YCOB crystal for giant-pulse green microlaser.

    PubMed

    Kausas, Arvydas; Loiseau, Pascal; Aka, Gerard; Zheng, Yanqing; Zheng, Lihe; Taira, Takunori

    2017-03-20

    In this work the performance of two yttrium calcium oxyborate (YCOB) crystals made by Czochralski and Bridgman growth process was measured. By using high peak power, passively Q-switched Nd3+:YAG/Cr4+:YAG microlaser, high conversion second harmonic generation efficiency were obtained. Laser pulses at 532 nm with 1.14 mJ energy and 223 ps duration were obtained with a 15-mm long YCOB crystal that was grown by Bridgman method. The conversion efficiency was 70.2%, comparable with the conversion efficiency of 72.8% that was achieved with 10-mm long lithium triborate (LBO) nonlinear crystal. Also, for the first time, experimental data on temperature tuning in type I YCOB crystal was measured with linear slope in 200°C temperature range equal to -0.057%/°C and -0.064%/°C for the Czochralski and Bridgman grown crystals, respectively. Such YCOB nonlinear crystal can become a serious option for developing laser sources with high-peak power at high repetition rate that can operate in harsh environment.

  16. Functionalizing Titanium Disilicide Nanonets with Cobalt Oxide and Palladium for Stable Li Oxygen Battery Operations.

    PubMed

    Yao, Xiahui; Cheng, Qingmei; Xie, Jin; Dong, Qi; Wang, Dunwei

    2015-10-07

    Li oxygen (Li-O2) batteries promise high energy densities but suffer from challenges such as poor cycling lifetime and low round-trip efficiencies. Recently, the instability of carbon cathode support has been recognized to contribute significantly to the problems faced by Li-O2 batteries. One strategy to address the challenge is to replace carbon materials with carbon-free ones. Here, we present titanium silicide nanonets (TiSi2) as such a new material platform for this purpose. Because TiSi2 exhibits no oxygen reduction reaction (ORR) or oxygen evolution reaction (OER) activities, catalysts are required to promote discharge and recharge reactions at reduced overpotentials. Pd nanoparticles grown by atomic layer deposition (ALD) were observed to provide the bifunctionalities of ORR and OER. Their adhesion to TiSi2 nanonets, however, was found to be poor, leading to drastic performance decay due to Pd detachments and aggregation. The problem was solved by adding another layer of Co3O4, also prepared by ALD. Together, the Pd/Co3O4/TiSi2 combination affords the desired functionalities and stability. Li-O2 test cells that lasted more than 126 cycles were achieved. The reversible formation and decomposition of Li2O2 was verified by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), ferrocenium back-titration, and gas-chromatography and mass spectrometry (GC-MS). Our results provide a new material platform for detailed studies of Li-O2 operations for better understanding of the chemistries involved, which is expected to help pave the way toward practical Li-O2 battery realizations.

  17. Operative Stabilization of Flail Chest Injuries Reduces Mortality to that of Stable Chest Wall Injuries.

    PubMed

    Dehghan, Niloofar; Mah, Jeffrey M; Schemitsch, Emil H; Nauth, Aaron; Vicente, Milena; McKee, Michael D

    2017-08-29

    To determine the prevalence, management and outcomes of patients with flail chest injuries, compared to patients without flail chest injuries (single rib fractures and multiple rib fractures without a flail segment). Retrospective cohort study SETTING:: Ontario, Canada PARTICIPANTS:: Ontario residents over the age of 16 who had been admitted to hospital with a chest wall injury from 2004 to 2015 were identified using administrative health care databases. Outcomes included treatment modalities such as rate of surgical repair, days on mechanical ventilation, days in the intensive care unit (ICU), days in hospital, rate of chest tube placement; and rates of complication, including pneumonia, tracheostomy, readmission, and death. In total 117,204 patients with fractures of the chest wall were identified. Of the entire cohort, 1.5% of had a flail chest injury, 41% had multiple rib fractures and 58% had single rib fractures. Flail chest patients had significantly worst outcomes compared to multiple rib fracture patients in all categories (p<0.0001). Similarly, multiple rib fracture patients had significantly worst outcomes compared to single rib fracture patients (p<0.0001). Only 4.5% of flail chest patients were treated surgically, however the number increased from 1% prior to 2010 to 10% after 2010 (p<0.0001). After adjustment for potential confounders, patients with flail chest injuries treated surgically had a reduced risk of early mortality compared to those treated non-operatively (OR 0.16, p=0.019). Surgical stabilization of flail chest has increased significantly in recent years. The results of this study provide preliminary evidence that the increasing rate of surgical intervention may be warranted by reducing mortality. Level III.

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

    SciTech Connect

    Zheng, Jianming; Yan, Pengfei; Mei, Donghai; Engelhard, Mark H.; Cartmell, Samuel S.; Polzin, Bryant; Wang, Chong M.; Zhang, Jiguang; Xu, Wu

    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 facilitate 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.

  19. 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

    2017-05-09

    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.

  20. Neuronal Diversity and Temporal Dynamics: The Unity of Hippocampal Circuit Operations

    PubMed Central

    Klausberger, Thomas; Somogyi, Peter

    2015-01-01

    In the cerebral cortex, diverse types of neurons form intricate circuits and cooperate in time for the processing and storage of information. Recent advances reveal a spatiotemporal division of labor in cortical circuits, as exemplified in the CA1 hippocampal area. In particular, distinct GABAergic (γ-aminobutyric acid–releasing) cell types subdivide the surface of pyramidal cells and act in discrete time windows, either on the same or on different subcellular compartments. They also interact with glutamatergic pyramidal cell inputs in a domain-specific manner and support synaptic temporal dynamics, network oscillations, selection of cell assemblies, and the implementation of brain states. The spatiotemporal specializations in cortical circuits reveal that cellular diversity and temporal dynamics coemerged during evolution, providing a basis for cognitive behavior. PMID:18599766

  1. Spatial and temporal variations in stable carbon (δ(13)C) and nitrogen (δ(15)N) isotopic composition of symbiotic scleractinian corals.

    PubMed

    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 (δ(13)C) and nitrogen (δ(15)N) 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 (13)C-depleted and (15)N-enriched relative to corals and photosymbionts from less turbid sites. However, differences in both δ(13)C and δ(15)N between coral host tissues and their photosymbionts (Δ(host-photosymbionts 13)C and Δ(host-photosymbionts 15)N) 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 δ(13)C and enriched δ(15)N 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 δ(13)C and δ(15)N values of coral host and photosymbiont tissues and in Δ(host-photosymbionts 13)C and Δ(host-photosymbionts 15)N 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

  2. Temporal synthesis of band 3 oligomers during terminal maturation of mouse erythroblasts. Dimers and tetramers exist in the membrane as preformed stable species.

    PubMed

    Hanspal, M; Golan, D E; Smockova, Y; Yi, S J; Cho, M R; Liu, S C; Palek, J

    1998-07-01

    Band 3, the anion transport protein of the erythrocyte membrane, exists in the membrane as a mixture of dimers (B3D) and tetramers (B3T). The dimers are not linked to the skeleton and constitute the free mobile band 3 fraction. The tetramers are linked to the skeleton by their interaction with ankyrin. In this report we have examined the temporal synthesis and assembly of band 3 oligomers into the plasma membrane during red cell maturation. The oligomeric state of newly synthesized band 3 in early and late erythroblasts was analyzed by size-exclusion high-pressure liquid chromatography of band 3 extracts derived by mild extraction of plasma membranes with the nonionic detergent C12E8 (octaethylene glycol n-dodecyl monoether). This analysis revealed that at the early erythroblast stage, the newly synthesized band 3 is present predominantly as tetramers, whereas at the late stages of erythroid maturation, it is present exclusively as dimers. To examine whether the dimers and tetramers exist in the membrane as preformed stable species or whether they are interconvertible, the fate of band 3 species synthesized during erythroblast maturation was examined by pulse-chase analysis. We showed that the newly synthesized band 3 dimers and tetramers are stable and that there is no interconversion between these species in erythroblast membranes. Pulse-chase analysis followed by cellular fractionation showed that, in early erythroblasts, the newly synthesized band 3 tetramers are initially present in the microsomal fraction and later incorporated stably into the plasma membrane fraction. In contrast, in late erythroblasts the newly synthesized band 3 dimers move rapidly to the plasma membrane fraction but then recycle between the plasma membrane and microsomal fractions. Fluorescence photobleaching recovery studies showed that significant fractions of B3T and B3D are laterally mobile in early and late erythroblast plasma membranes, respectively, suggesting that many B3T

  3. 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.

  4. Second Order of Accuracy Stable Difference Schemes for Hyperbolic Problems Subject to Nonlocal Conditions with Self-Adjoint Operator

    NASA Astrophysics Data System (ADS)

    Ashyralyev, Allaberen; Yildirim, Ozgur

    2011-09-01

    In the present paper, two new second order of accuracy absolutely stable difference schemes are presented for the nonlocal boundary value problem {d2u(t)/dt2+Au(t) = f(t) (0≤t≤1),u(0) = ∑ j = 1nαju(λj)+φ,ut(0) = ∑ j = 1nβjut(λj)+ψ,0<λ1<λ2<…<λn≤1 for differential equations in a Hilbert space H with the self-adjoint positive definite operator A. The stability estimates for the solutions of these difference schemes are established. In practice, one-dimensional hyperbolic equation with nonlocal boundary conditions and multidimensional hyperbolic equation with Dirichlet conditions are considered. The stability estimates for the solutions of difference schemes for the nonlocal boundary value hyperbolic problems are obtained and the numerical results are presented to support our theoretical statements.

  5. First experimental demonstration of temporal hypertelescope operation with a laboratory prototype

    NASA Astrophysics Data System (ADS)

    Bouyeron, L.; Olivier, S.; Delage, L.; Reynaud, F.; Armand, P.; Bousquet, E.; Benoist, J.

    2010-11-01

    In this paper, we report the first experimental demonstration of a temporal hypertelescope (THT). Our breadboard including eight telescopes is first tested in a manual cophasing configuration on a one-dimensional object. The point-spread function (PSF) is measured and exhibits dynamics in the range of 300. A quantitative analysis of the potential biases demonstrates that this limitation is related to the residual-phase fluctuation on each interferometric arm. Secondly, an unbalanced binary star is imaged, demonstrating the imaging capability of THTs. In addition, a two-dimensional PSF is recorded, even if the telescope array is not optimized for this purpose.

  6. Temporal-Bone Measurements of the Maximum Equivalent Pressure Output and Maximum Stable Gain of a Light Driven Hearing System that Mechanically Stimulates the Umbo

    PubMed Central

    Puria, Sunil; Santa Maria, Peter Luke; Perkins, Rodney

    2015-01-01

    Hypothesis That maximum equivalent pressure output (MEPO) and maximum stable gain (MSG) measurements demonstrate high output and high gain margins in a Light Driven Hearing System (Earlens). Background The non-surgical Earlens consists of a light-activated balanced-armature Tympanic Lens (Lens) to drive the middle ear through direct umbo contact. The Lens is driven and powered by encoded pulses of light. In comparison to conventional hearing aids, the Earlens is designed to provide higher levels of output over a broader frequency range and a significantly higher MSG with the MEPO providing an important fitting guideline. Methods Four fresh human cadaver temporal bones were used to measure MEPO directly. To calculate MEPO and MSG, we measured the pressure close to the eardrum and stapes velocity for sound drive and light drive using the Earlens. Results The baseline sound-driven measurements are consistent with previous reports. The average MEPO (N=4) varies from 116 to 128 dB SPL in the 0.7 to 10 kHz range, with the peak occurring at 7.6 kHz. From 0.1–0.7 kHz, it varies from 83 to 121 dB SPL. For the average MSG, a broad minimum of about 10 dB occurs in the 1–4 kHz range, above which it rises as high as 42 dB at 7.6 kHz. From 0.2 to 1 kHz, the MSG decreases linearly from about 40 dB to 10 dB. Conclusion With high output and high gain margins, the Earlens may offer broader spectrum amplification for treatment of mild to severe hearing impairment. PMID:26756140

  7. 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.

  8. 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.

  9. 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.

  10. Hours of Boredom, Moments of Terror: Temporal Desynchrony in Military and Security Force Operations

    DTIC Science & Technology

    2010-10-01

    activity in the 2–3 hour range is well tolerated but prolonged activities which exceed a period of 4 hours in duration tend to prove more problematic...transition both in basic and advanced training. This is difficult since the “ adrenaline rush” of real operations is never quite replicated in

  11. Performance and microbial population dynamics during stable operation and reactivation after extended idle conditions in an aerobic granular sequencing batch reactor.

    PubMed

    He, Qiulai; Zhang, Wei; Zhang, Shilu; Zou, Zhuocheng; Wang, Hongyu

    2017-08-01

    The evolution of removal performance and bacterial population dynamics of an aerobic granular sequencing batch reactor were investigated during stable operation and reactivation after prolonged storage. The system was run for a period of 130days including the stable condition phase, storage period and the subsequent reactivation process. Excellent removal performance was obtained during the stable operation period, which was decayed by the extended idle conditions. The removal efficiencies for both carbon and nitrogen decayed while phosphorus removal remained unaffected. Both granules structure and physical properties could be fully restored. Microbial populations shifted sharply and the storage perturbations irreversibly altered the microbial communities at different levels. Extracellular polymeric substances (especially protein) and key groups were identified as contributors for storage and re-startup of the aerobic granular system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Mesocortical dopamine neurons operate in distinct temporal domains using multimodal signaling.

    PubMed

    Lavin, Antonieta; Nogueira, Lourdes; Lapish, Christopher C; Wightman, R Mark; Phillips, Paul E M; Seamans, Jeremy K

    2005-05-18

    In vivo extracellular recording studies have traditionally shown that dopamine (DA) transiently inhibits prefrontal cortex (PFC) neurons, yet recent biophysical measurements in vitro indicate that DA enhances the evoked excitability of PFC neurons for prolonged periods. Moreover, although DA neurons apparently encode stimulus salience by transient alterations in firing, the temporal properties of the PFC DA signal associated with various behaviors is often extraordinarily prolonged. The present study used in vivo electrophysiological and electrochemical measures to show that the mesocortical system produces a fast non-DA-mediated postsynaptic response in the PFC that appears to be initiated by glutamate. In contrast, short burst stimulation of mesocortical DA neurons that produced transient (<4 s) DA release in the PFC caused a simultaneous reduction in spontaneous firing (consistent with extracellular in vivo recordings) and a form of DA-induced potentiation in which evoked firing was increased for tens of minutes (consistent with in vitro measurements). We suggest that the mesocortical system might transmit fast signals about reward or salience via corelease of glutamate, whereas the simultaneous prolonged DA-mediated modulation of firing biases the long-term processing dynamics of PFC networks.

  13. Spatial and temporal trends in water-use efficiency across U.S. forests: integrating tree ring stable C and O isotopes with eddy covariance data

    NASA Astrophysics Data System (ADS)

    Asbjornsen, H.; Guerrieri, R.; Belmecheri, S.; Martin, M.; Lepine, L. C.; Jennings, K.; Xiao, J.; Ollinger, S. V.

    2016-12-01

    Understanding relations among forest carbon (C) uptake and water use is critical for predicting forest-climate interactions. Water use efficiency (WUE), the carbon (C) gain per unit of water (H2O) loss through transpiration, is the key physiological trait linking C and H2O cycling in forests, and allowing to monitor ecosystem productivity in response to climate change. Stable C isotope composition (δ13C) in tree rings has been extensively used to assess the changes in the tree-level intrinsic WUE (i.e., iWUE - photosynthesis, A/stomatal conductance, gs) in response to climate and anthropogenic forcing (e.g., increase in atmospheric CO2 and nitrogen deposition) over the last century for several forest ecosystems worldwide. At the forest ecosystem level, WUE (WUEe) is obtained as ratio between Gross Primary Productivity (GPP) and evapotranspiration (ET), derived from the eddy covariance measurements. Very few studies compared the two approaches, most of them to date have focused on within-site comparisons. Moreover, most studies examining the influence of climatic factors on tree-WUE have focused on water-limited ecosystems in the Southwest, while much less is known about the dynamics of WUE for mesic forests in the Eastern US. In this study, we compared the two methods across a range of eight to eleven forested Ameriflux sites and climate in the U.S. Furthermore, we examined whether species-specific physiological mechanisms facilitated a better understanding of the ecosystem fluxes. We will present 30-year δ13C (and derived iWUE) and δ18O tree-ring chronologies and foliar isotopes obtained from two dominant species at each site. Spatial (across sites) and temporal trend of tree WUE will then be compared to ecosystem WUE as obtained from eddy covariance data. Relationships between δ13C and δ18O will be explored to elucidate the species-specific physiological mechanisms underlying variation in iWUE. Moreover, drivers of the changes in WUE at the two scales (i

  14. 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

  15. 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.

  16. Temporally and functionally dissociable retrieval processing operations revealed by event-related potentials.

    PubMed

    Cruse, Damian; Wilding, Edward L

    2011-06-01

    In a pair of recent studies, frontally distributed event-related potential (ERP) indices of two distinct post-retrieval processes were identified. It has been proposed that one of these processes operates over any kinds of task relevant information in service of task demands, while the other operates selectively over recovered contextual (episodic) information. The experiment described here was designed to test this account, by requiring retrieval of different kinds of contextual information to that required in previous relevant studies. Participants heard words spoken in either a male or female voice at study and ERPs were acquired at test where all words were presented visually. Half of the test words had been spoken at study. Participants first made an old/new judgment, distinguishing via key press between studied and unstudied words. For words judged 'old', participants indicated the voice in which the word had been spoken at study, and their confidence (high/low) in the voice judgment. There was evidence for only one of the two frontal old/new effects that had been identified in the previous studies. One possibility is that the ERP effect in previous studies that was tied specifically to recollection reflects processes operating over only some kinds of contextual information. An alternative is that the index reflects processes that are engaged primarily when there are few contextual features that distinguish between studied stimuli.

  17. Spatio-temporal operator formalism for holographic recording and diffraction in a photorefractive-based true-time-delay phased-array processor.

    PubMed

    Kiruluta, Andrew; Pati, Gour S; Kriehn, Gregory; Silveira, Paulo E X; Sarto, Anthony W; Wagner, Kelvin

    2003-09-10

    We present a spatio-temporal operator formalism and beam propagation simulations that describe the broadband efficient adaptive method for a true-time-delay array processing (BEAMTAP) algorithm for an optical beamformer by use of a photorefractive crystal. The optical system consists of a tapped-delay line implemented with an acoustooptic Bragg cell, an accumulating scrolling time-delay detector achieved with a traveling-fringes detector, and a photorefractive crystal to store the adaptive spatio-temporal weights as volume holographic gratings. In this analysis, linear shift-invariant integral operators are used to describe the propagation, interference, grating accumulation, and volume holographic diffraction of the spatio-temporally modulated optical fields in the system to compute the adaptive array processing operation. In addition, it is shown that the random fluctuation in time and phase delays of the optically modulated and transmitted array signals produced by fiber perturbations (temperature fluctuations, vibrations, or bending) are dynamically compensated for through the process of holographic wavefront reconstruction as a byproduct of the adaptive beam-forming and jammer-excision operation. The complexity of the cascaded spatial-temporal integrals describing the holographic formation, and subsequent readout processes, is shown to collapse to a simple imaging condition through standard operator manipulation. We also present spatio-temporal beam propagation simulation results as an illustrative demonstration of our analysis and the operation of a BEAMTAP beamformer.

  18. 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)

  19. 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)

  20. Informing the operations of water reservoirs over multiple temporal scales by direct use of hydro-meteorological data

    NASA Astrophysics Data System (ADS)

    Denaro, Simona; Anghileri, Daniela; Giuliani, Matteo; Castelletti, Andrea

    2017-05-01

    Water reservoir systems may become more adaptive and reliable to external changes by enlarging the information sets used in their operations. Models and forecasts of future hydro-climatic and socio-economic conditions are traditionally used for this purpose. Nevertheless, the identification of skillful forecasts and models might be highly critical when the system comprises several processes with inconsistent dynamics (fast and slow) and disparate levels of predictability. In these contexts, the direct use of observational data, describing the current conditions of the water system, may represent a practicable and zero-cost alternative. This paper contrasts the relative contribution of state observations and perfect forecasts of future water availability in improving multipurpose water reservoirs operation over short- and long-term temporal scales. The approach is demonstrated on the snow-dominated Lake Como system, operated for flood control and water supply. The Information Selection Assessment (ISA) framework is adopted to retrieve the most relevant information to be used for conditioning the operations. By explicitly distinguishing between observational dataset and future forecasts, we quantify the relative contribution of current water system state estimates and perfect streamflow forecasts in improving the lake regulation with respect to both flood control and water supply. Results show that using the available observational data capturing slow dynamic processes, particularly the snow melting process, produces a 10% improvement in the system performance. This latter represents the lower bound of the potential improvement, which may increase to the upper limit of 40% in case skillful (perfect) long-term streamflow forecasts are used.

  1. The Nature of Temporally Variable Methane Emissions at Oil and Natural Gas Operations in the Eagle Ford Basin

    NASA Astrophysics Data System (ADS)

    Lavoie, T. N.; Shepson, P. B.; Cambaliza, M. O. L.; Stirm, B. H.; Conley, S. A.; Mehrotra, S.; Faloona, I. C.; Mayfield, M.; Lyon, D. R.; Alvarez, R.

    2015-12-01

    To understand the current state of U.S. greenhouse gas emissions from oil and gas operations, policy makers refer to national inventories and reporting programs, and therefore, it is imperative that these reports are accurate and representative. Many studies exist that investigate the reliability of current monitoring methods, however, to our knowledge the temporal variability of the magnitude and source of methane (CH4) emissions from oil and gas facilities has not been reported in the literature. We present results from a field campaign conducted in June 2014 in the Eagle Ford basin, Texas to assess the temporal variability of emissions from a variety of facilities using data obtained through four different methods. The variability of total CH4 emission rate from individual facilities was investigated by repeated measurement of emissions from five gathering facilities using two aircraft-based mass balance approaches. Basin-wide emissions variation was examined by conducting a series of eight four hour afternoon aerial surveys of two 35 x 35 km areas, with transects oriented perpendicular to the prevailing wind direction. The emission source-type and magnitude were further investigated using helicopter-based FLIR camera observations conducted repeatedly at eight oil wells, one gas well, and four gathering facilities. Results indicate a high degree of variability in day-to-day and sometimes hour-to-hour CH4 emissions magnitude. FLIR camera observations suggest that the component-level source of facility emissions is also highly variable over time, with both storage tank vent stacks and tank hatches representing important components of the observed day-to-day variability. While some emissions were due to scheduled maintenance, others appeared to occur due to faulty and/or aging equipment. Here we discuss what was learned in terms of factors that explain the observed emission rate variability.

  2. 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.

  3. 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.

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

    PubMed

    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

  5. 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

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

    SciTech Connect

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

    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; 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

  7. 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

  8. Temporal variatiions of Sea ice cover in the Baltic Sea derived from operational sea ice products used in NWP.

    NASA Astrophysics Data System (ADS)

    Lange, Martin; Paul, Gerhard; Potthast, Roland

    2014-05-01

    Sea ice cover is a crucial parameter for surface fluxes of heat and moisture over water areas. The isolating effect and the much higher albedo strongly reduces the turbulent exchange of heat and moisture from the surface to the atmosphere and allows for cold and dry air mass flow with strong impact on the stability of the whole boundary layer and consequently cloud formation as well as precipitation in the downstream regions. Numerical weather centers as, ECMWF, MetoFrance or DWD use external products to initialize SST and sea ice cover in their NWP models. To the knowledge of the author there are mainly two global sea ice products well established with operational availability, one from NOAA NCEP that combines measurements with satellite data, and the other from OSI-SAF derived from SSMI/S sensors. The latter one is used in the Ostia product. DWD additionally uses a regional product for the Baltic Sea provided by the national center for shipping and hydrografie which combines observations from ships (and icebreakers) for the German part of the Baltic Sea and model analysis from the hydrodynamic HIROMB model of the Swedish meteorological service for the rest of the domain. The temporal evolution of the three different products are compared for a cold period in Februar 2012. Goods and bads will be presented and suggestions for a harmonization of strong day to day jumps over large areas are suggested.

  9. 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

    SciTech Connect

    Garofalo, Andrea M.; Burrell, Keith H.; Eldon, David; Grierson, Brian A.; Hanson, Jeremy M.; Holland, Christopher; Huijsmans, Guido T. A.; Liu, Feng; Loarte, Alberto; Meneghini, Orso; Osborne, T. H.; Paz-Soldan, C.; Smith, S. P.; Snyder, P. B.; Solomon, W. M.; Turnbull, A. D.; Zeng, L.

    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, 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.

  10. 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

  11. 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

  12. Temporal Scaling of Age-Dependent Mortality: Dynamics of Aging in Caenorhabditis elegans Is Easy to Speed Up or Slow Down, but Its Overall Trajectory Is Stable.

    PubMed

    Markov, A V; Naimark, E B; Yakovleva, E U

    2016-08-01

    The dynamics of aging is often described by survival curves that show the proportion of individuals surviving to a given age. The shape of the survival curve reflects the dependence of mortality on age, and it varies greatly for different organisms. In a recently published paper, Stroustrup and coauthors ((2016) Nature, 530, 103-107) showed that many factors affecting the lifespan of Caenorhabditis elegans do not change the shape of the survival curve, but only stretch or compress it in time. Apparently, this means that aging is a programmed process whose trajectory is difficult to change, although it is possible to speed it up or slow it down. More research is needed to clarify whether the "rule of temporal scaling" is applicable to other organisms. A good indicator of temporal scaling is the coefficient of lifespan variation: similar values of this coefficient for two samples indicate similar shape of the survival curves. Preliminary results of experiments on adaptation of Drosophila melanogaster to unfavorable food show that temporal scalability of survival curves is sometimes present in more complex organisms, although this is not a universal rule. Both evolutionary and environmental changes sometimes affect only the average lifespan without changing the coefficient of variation (in this case, temporal scaling is present), but often both parameters (i.e. both scale and shape of the survival curve) change simultaneously. In addition to the relative stability of the coefficient of variation, another possible argument in favor of genetic determination of the aging process is relatively low variability of the time of death, which is sometimes of the same order of magnitude as the variability of timing of other ontogenetic events, such as the onset of sexual maturation.

  13. 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.

  14. 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. We coupled a nominal 935 run-wavelength Fabry-Perot laser diode to an ultra narrow band (18 pm) FBG. When tuned by varying its temperature, the laser wavelength is pulled toward the centerline of the Bragg grating, and the spectrum of the laser output is seen to fall into three discrete stability regimes as measured by the side-mode suppression ratio.

  15. The quiescent H-mode regime for high performance edge localized mode-stable operation in future burning plasmas

    SciTech Connect

    Garofalo, A. M. Burrell, K. H.; Meneghini, O.; Osborne, T. H.; Paz-Soldan, C.; Smith, S. P.; Snyder, P. B.; Turnbull, A. D.; Eldon, D.; Grierson, B. A.; Solomon, W. M.; Hanson, J. M.; Holland, C.; Huijsmans, G. T. A.; Liu, F.; Loarte, A.; Zeng, L.

    2015-05-15

    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-like 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, 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. The DIII-D results are in excellent agreement with these predictions, and nonlinear magnetohydrodynamic 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.

  16. 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.

  17. Spatial and temporal expression of vegetation and atmospheric variability from stable carbon and nitrogen isotope analysis of bat guano in the southern United States

    NASA Astrophysics Data System (ADS)

    Wurster, Christopher M.; McFarlane, Donald A.; Bird, Michael I.

    2007-07-01

    Stable isotopes of faeces contain information related to the animals feeding ecology. The use of stable isotope values from subfossil faeces as a palaeoenvironmental indicator depends on how faithfully the animal records their local environment. Here we present insectivorous bat guano δ 13C and δ 15N values from a precipitation gradient across the southern United States and northern Mexico to compare with local vegetation and climate. We find δ 13C values to be an excellent predictor of expected C 4/CAM vegetation, indicating that the bats are non-selective in their diet. Moreover, we find bat guano δ 13C values to be strongly correlated with summer precipitation amount and winter precipitation ratio. We also find evidence for a significant relationship with mean annual temperature. In general, we do not find δ 15N values to be related to any parameters along the climatic gradient we examined. Additionally, we measured δ 13C and δ 15N values of bulk guano deposited annually from 1968 to 1987 in a varved guano deposit at Eagle Creek Cave, Arizona. Neither δ 13C nor δ 15N values were significantly related to various local meteorological variables; however, we found δ 13C values of guano to be significantly related to drought and to the North American Monsoon indicating bat guano δ 13C values preserve an interpretable record of large-scale atmospheric variability.

  18. Future fitness of female insect pests in temporally stable and unstable habitats and its impact on habitat utility as refugees for insect resistance management.

    PubMed

    Caprio, Michael A; Parker, C D; Schneider, John C

    2009-01-01

    The long-term fitness of individuals is examined in complex and temporally dynamic ecosystems. We call this multigeneration fitness measure "future fitness". Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is a polyphagous insect that feeds on many wild and cultivated hosts. While four generations of H. zea occur during the cropping season in the U.S. Mid Southern agroecosysem, the latter two generations were of most interest, as corn (which has been largely nontransgenic in the Mid-South) dominates the first two generations in the cropping system. In simulations of the evolution of resistance to Bt-transgenic crops, cotton refuge areas were found to be significantly more effective than similar soybean acreages at delaying the evolution of resistance. Cotton is a suitable host for H. zea during two late summer generations, while a soybean field is suitable for only one of these generations, therefore soybean fields of other maturity groups were simulated as being attractive during the alternative generation. A hypothetical soybean variety was tested in which a single field would be attractive over both generations and it was found to be significantly more effective at delaying resistance than simulated conventional soybean varieties. Finally, the placement of individuals emerging at the start of the 3rd (first without corn) generation was simulated in either refuge cotton, conventional soybean and the hypothetical long attractive soybean and the mean number of offspring produced was measured at the end of the season. Although females in conventional and long soybean crops had the same expected fecundity, because of differences in temporal stability of the two crops, the long soybean simulations had significantly more H. zea individuals at the end of the season than the conventional soybean simulations. These simulations demonstrate that the long-term fecundity associated with an individual is dependent not only on the fecundity of that individual in its current

  19. Interpretation of anthropogenic impacts (agriculture and urbanization) on tropical deltaic river network through the spatio-temporal variation of stable (N, O) isotopes of NO(-)3.

    PubMed

    Ta, Thi Thao; Le, Si Hung; Trinh, Hong Quan; Luu, Thi Nguyet Minh; Trinh, Anh Duc

    2016-01-01

    For the first time, the dual isotope approach was applied to trace the sources of impacts and to identify the governing biogeochemical processes in a river network in the tropical deltaic region of the Red River (Vietnam). Our long term surveys concluded that water in this river network was severely impacted by anthropogenic activities. Analysis has shown strong spatio-temporal variation of nitrate isotopes; ranges of δ(15)N-[Formula: see text] and δ(18)O-[Formula: see text] were from -5 to 15 ‰ and from -10 to 10 ‰, respectively. Average values of δ(15)N-[Formula: see text] and δ(18)O-[Formula: see text] in the dry season, when fertilizer is applied, were 3.54 and 3.15 ‰, respectively. In the rainy season, the values changed to 6.41 and -2.23 ‰, respectively. Denitrification and biological assimilation were active throughout the year, but were especially enhanced during fertilization time. Mineralization of domestic organic matter and consequent nitrification of mineralized [Formula: see text] were the dominant processes, particularly during the rainy period.

  20. Sequence Variation in the T-Cell Epitopes of the Plasmodium falciparum Circumsporozoite Protein among Field Isolates Is Temporally Stable: a 5-Year Longitudinal Study in Southern Vietnam

    PubMed Central

    Jalloh, Amadu; van Thien, Huynh; Ferreira, Marcelo U.; Ohashi, Jun; Matsuoka, Hiroyuki; Kanbe, Toshio; Kikuchi, Akihiko; Kawamoto, Fumihiko

    2006-01-01

    In an effort to decipher the nature and extent of antigen polymorphisms of malaria parasites in a setting where malaria is hypomesoendemic, we conducted a 5-year longitudinal study (1998 to 2003) by sequencing the Th2R and Th3R epitopes of the circumsporozoite protein (CSP) of 142 Plasmodium falciparum field isolates from Bao Loc, Vietnam. Samples were collected during the high-transmission season, September through December 1998 (n = 43), as well as from July 2000 to August 2001 (n = 34), September 2001 to July 2002 (n = 33), and August 2002 to July 2003 (n = 32). Marked sequence diversity was noted during the high-transmission season in 1998, but no significant variation in allele frequencies was observed over the years (χ2 = 70.003, degrees of freedom = 57, P = 0.116). The apparent temporal stability in allele frequency observed in this Bao Loc malaria setting may suggest that polymorphism in the Th2R and Th3R epitopes is not maintained by frequency-dependent immune selection. By including 36 isolates from Flores Island, Indonesia, and 19 isolates from Thaton, Myanmar, we investigated geographical patterns of sequence polymorphism for these epitopes in Southeast Asia; among the characterized isolates, a globally distributed variant appears to be predominant in Vietnam (75 of 142 isolates, or 52.8%) as well as in Myanmar (15 of 19 isolates, or 78.9%) and Indonesia (31 of 36 isolates, or 86.1%). Further analyses involving worldwide CSP sequences revealed distinct regional patterns, a finding which, together with the unique mutations observed here, may suggest a possible role for host or local factors in the generation of sequence diversity in the T-cell epitopes of CSP. PMID:16597843

  1. [The influence of hypersensitivity to nickel, chrome and cobalt on the process of fracture healing in patients treated operatively by stable osteosynthesis].

    PubMed

    Dobiecki, Konrad; Zietek, Paweł; Kołodziej, Lukasz; Brzosko, Marek; Bohatyrewicz, Andrzej; Kedzierski, Michał

    2009-01-01

    The aim of the study was to evaluate the frequency of occurrence of the hypersensitivity to nickel, chrome and cobalt in patients with longbone fractures. Two groups of patients were compared. The first group was composed of those treated operatively by stable osteosynthesis with the use of metal implants. The control group consisted of patients who have never been operated. Additionally, the influence of recognized hypersensitivity on the process of fracture healing was estimated. The study group consisted of 80 and the control group of 65 patients. All patients were patch tested with metal salts. The correlation was sought between hypersensitivity to metal in the study group, and incidence of complications relating to fracture healing. There was no significant difference observed both in frequency of occurrence of hypersensitivity to nickel, chrome and cobalt among patients treated operatively, and those treated conservatively, as well. There was no correlation between occurrence of hypersensitivity to the ions of metals, and complications in the process of fracture healing.

  2. Six-decade temporal change and seasonal decomposition of climate variables in Lake Dianchi watershed (China): stable trend or abrupt shift?

    NASA Astrophysics Data System (ADS)

    Zhou, Jing; Liang, Zhongyao; Liu, Yong; Guo, Huaicheng; He, Dan; Zhao, Lei

    2015-01-01

    Meteorological trend analysis is a useful tool for understanding climate change and can provide useful information on the possibility of future change. Lake Dianchi is the sixth largest freshwater body in China with serious eutrophication. Algal blooms outbreak was proven to be closely associated with some climatic factors in Lake Dianchi. It is therefore essential to explore the trends of climatic time series to understand the mechanism of climate change on lake eutrophication. We proposed an integrated method of Mann-Kendall (MK) test, seasonal-trend decomposition using locally weighted regression (LOESS) (STL), and regime shift index (RSI) to decompose the trend analysis and identify the stable and abrupt changes of some climate variables from 1951 to 2009. The variables include mean air temperature (Tm), maximum air temperatures (Tmax), minimum air temperatures (Tmin), precipitation (Prec), average relative humidity (Hum), and average wind speed (Wind). The results showed that (a) annual Tm, Tmax, and Tmin have a significant increasing trend with the increasing rates of 0.26, 0.15and 0.43 °C per decade, respectively; (b) annual precipitation has an insignificant decreasing trend with the decreasing rate of 3.17 mm per decade; (c) annual Hum has a significant decreasing trend in all seasons; and (d) there are two turning points for temperature rise around 1980 and 1995 and two abrupt change periods for precipitation with the extreme points appearing in 1963 and 1976. Temperature rise and precipitation decline in summer and autumn as well as wind speed decrease after the 1990s may be an important reason for algal blooms outbreak in Lake Dianchi. This study was expected to provide foundation and reference for regional water resource management.

  3. 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.

  4. Reduction of RF accelerating voltage of Pohang Light Source-II superconducting RF cavity for stable top-up mode operation

    NASA Astrophysics Data System (ADS)

    Joo, Y.; Yu, I.; Park, I.; Chun, M. H.; Sohn, Y.

    2017-03-01

    The Pohang Light Source-II (PLS-II) is currently providing a top-up mode user-service operation with maximum available beam current of 400 mA and a beam emittance of below 10 nm-rad. The dimension of the beam bunch shortened to accomplish a low beam emittance of below 10 nm-rad from a high beam current of 400 mA increases the bunch charge density. As a result, the electron beam lifetime is significantly degraded and a high gradient of power is lost in the vacuum components of the storage ring. A study on how to reduce the bunch charge density without degrading beam emittance found that reducing the RF accelerating voltage (Vacc) can lower the bunch charge density by lengthening the bunch in the longitudinal direction. In addition, the Vacc required for stable operation with beam current of 400 mA can be reduced by lowering the external cavity quality factors (Qext values) of the superconducting cavities (SCs). To control the Qext values of SCs gradually without accessing the accelerator tunnel, a remote control motorized three-probe-tuner was installed in the transmission line of each SC. The optimum installation position of the three-probe-tuner was determined by using a finite-difference time-domain (FDTD) simulation and by experimenting on various installation positions of the three-probe-tuner. The Qext values of all the SCs were lowered to 1.40 × 105, and then, the Vacc required to store the beam current of 400 mA was decreased from 4.8 MV to 4.2 MV, which corresponds to 10% lengthening of the beam bunches. The stable operation with the reduced Vacc was confirmed during a 400 mA ten-day top-up mode user-service. Currently, the RF system of the PLS-II storage ring delivers the user-service operation with lowered Qext values to reduce the power loss at the vacuum components as well as the cryogenic heat load of SCs, and no significant problems have been found. This method of reducing the Vacc may also be applied in other synchrotron facilities.

  5. 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 Central

    KHALIL, Amr Farid; IWASAKI, Masaki; NISHIO, Yoshiyuki; JIN, Kazutaka; NAKASATO, Nobukazu; TOMINAGA, Teiji

    2016-01-01

    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. PMID:27250575

  6. 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.

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

    PubMed

    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

  8. 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

  9. 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.

  10. Niche partition of Bacteriovorax operational taxonomic units along salinity and temporal gradients in the Chesapeake Bay reveals distinct estuarine strains.

    PubMed

    Pineiro, Silvia; Chauhan, Ashvini; Berhane, Timkhite-kulu; Athar, Rana; Zheng, Guili; Wang, Cynthia; Dickerson, Tamar; Liang, Xiaobing; Lymperopoulou, Despoina S; Chen, Huan; Christman, Mary; Louime, Clifford; Babiker, Wisal; Stine, O Colin; Williams, Henry N

    2013-04-01

    The predatory Bacteriovorax are Gram-negative bacteria ubiquitous in saltwater systems that prey upon other Gram-negative bacteria in a similar manner to the related genus Bdellovibrio. Among the phylogenetically defined clusters of Bacteriovorax, cluster V has only been isolated from estuaries suggesting that it may be a distinct estuarine phylotype. To assess this hypothesis, the spatial and temporal distribution of cluster V and other Bacteriovorax phylogenetic assemblages along the salinity gradient of Chesapeake Bay were determined. Cluster V was expected to be found in significantly greater numbers in low to moderate salinity waters compared to high salinity areas. The analyses of water and sediment samples from sites in the bay revealed cluster V to be present at the lower salinity and not high salinity sites, consistent with it being an estuarine phylotype. Cluster IV had a similar distribution pattern and may also be specifically adapted to estuaries. While the distribution of clusters V and IV were similar for salinity, they were distinct on temperature gradients, being found in cooler and in warmer temperatures, respectively. The differentiation of phylotype populations along the salinity and temporal gradients in Chesapeake Bay revealed distinct niches inhabited by different phylotypes of Bacteriovorax and unique estuarine phylotypes.

  11. 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.

  12. 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.

  13. Stable, tunable, and single-mode operation of an erbium-doped fibre laser system using a saturable absorber for gas spectroscopy applications

    NASA Astrophysics Data System (ADS)

    Arsad, Norhana; Stewart, George

    2009-02-01

    We present an erbium doped fibre ring laser system to realize single frequency lasing by incorporating a reflector with ~2m of un-pumped polarization-maintaining erbium-doped fibre to act as a saturable absorber. Depending on the particular requirements, the fibre reflector may be a fibre Bragg grating (FBG), loop mirror (LM) or a reflective coating on the fibre end. In this way, a transient grating is formed in the saturable absorber which acts as a narrow-band optical filter, reducing the number of modes over which the laser can operate and hence suppressing mode hopping in the cavity. Polarization-maintaining (PM) components are used throughout the system, except for the EDFA, and a polarization controller is used for enhancing stability and to ensure that the state of polarization is properly aligned. With this system we have observed a long period of stable, narrow line-width and single mode operation, tuneable over 30nm. The intended application is for gas spectroscopy using wavelength scanning and pump modulation. A Sagnac loop filter (SLF) can be used to scan the centre wavelength over a gas absorption line while the pump modulation produces an amplitude modulated signal on the output, suitable for detection by a lock-in (phase-sensitive) amplifier. The method is useful for the recovery of absorption line-shapes in the near-IR where the overtone absorption lines are weak. Compared with the use of a traditional DFB laser source, the fibre laser offers the advantages of a much broader tuning range and recovery of distortion-free line-shapes since wavelength and amplitude modulation may be performed independently.

  14. 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.

  15. Experimental analysis of spatio-temporal behavior of anodic dead-end mode operated polymer electrolyte fuel cell

    NASA Astrophysics Data System (ADS)

    Manokaran, A.; Pushpavanam, S.; Sridhar, P.; Pitchumani, S.

    During the anodic dead-end mode operation of fuel cells, the inert gases (nitrogen and water) present in the cathode side gas channel permeate to the anode side and accumulate in the anode gas channel. The inert gas accumulation in the anode decreases the fuel cell performance by impeding the access of hydrogen to the catalyst. The performance of fuel cell under potentiostatic dead-end mode operation is shown to have three distinct regions viz. time lag region, transient current region and a steady state current region. A current distribution measurement setup is used to capture the evolution of the current distribution as a function of time and space. Co- and counter-flow operations of dead-end mode confirm the propagation of inert gas from the dead-end of anode channel to the inlet of anode. Experiments with different oxidants, oxygen and air, under dead-end mode confirm that nitrogen which permeates from cathode to anode causes the performance drop of the fuel cell. For different starting current densities of 0.15 A cm -2, 0.3 A cm -2 and 0.6 A cm -2 the inert gas occupies 35%, 45% and 57%, respectively of anode channel volume at the end of 60 min of dead-end mode operation.

  16. Stable angina

    MedlinePlus

    ... stable; Angina - chronic; Angina pectoris; Chest pain - angina; CAD - angina; Coronary artery disease - angina; Heart disease - angina ... clot. The most common cause of angina is coronary artery disease . Angina pectoris is the medical term for this ...

  17. Revisiting the use of δ15N in meso-scale studies of marine food webs by considering spatio-temporal variations in stable isotopic signatures - The case of an open ecosystem: The Bay of Biscay (North-East Atlantic)

    NASA Astrophysics Data System (ADS)

    Chouvelon, T.; Spitz, J.; Caurant, F.; Mèndez-Fernandez, P.; Chappuis, A.; Laugier, F.; Le Goff, E.; Bustamante, P.

    2012-08-01

    Most of the recent framework directives and environmental policies argue for the development and the use of indicators - notably trophodynamic indicators - that should be able to follow ecosystems' evolution in space and time, particularly under anthropogenic perturbations. In the last decades, the use of stable carbon and nitrogen isotopes ratios has increased exponentially, particularly in studies of marine ecosystems' trophic structure and functioning. This method is principally based on the assumption that the isotopic composition of a consumer directly reflects that of its food. Nevertheless, few studies have attempted to define the limits of this tool, before using it and drawing ecological conclusions from isotopic analysis. This study aimed to assess the importance of considering spatio-temporal variations in isotopic signatures of consumers when using δ13C and especially δ15N values in open ecosystems with complex food webs, using the Bay of Biscay (North-East Atlantic) as a case study. To this end, more than 140 species from this marine ecosystem were analysed for the isotopic signatures in their muscle tissue. They were sampled from coastal to oceanic and deep-sea areas and at different latitudes, to evaluate spatial variations of isotopic signatures. Selected species were also sampled over several years and in two seasons to account for inter-annual and seasonal variations. In the Bay of Biscay temperate ecosystem, which is subject to both coastal and oceanic influences - two main river inputs and upwelling areas - , δ13C and δ15N values significantly decreased from inshore to offshore species, and to a lesser extent from benthic to pelagic organisms. River discharges appeared to be the first factor influencing δ13C and δ15N values in consumers. From the important spatial variations detected in δ15N values in particular, we suggest that in such contrasted ecosystem, nitrogen isotopic ratios may also be revisited as an indicator of the feeding

  18. Gridded precipitation fields at high temporal and spatial resolution for operational flood forecasting in the Rhine basin

    NASA Astrophysics Data System (ADS)

    van Osnabrugge, Bart; Weerts, Albrecht; Uijlenhoet, Remko

    2017-04-01

    Gridded areal precipitation, as one of the most important hydrometeorological input variables for initial state estimation in operational hydrological forecasting, is available in the form of raster data sets (e.g. HYRAS and EOBS) for the River Rhine basin. These datasets are compiled off-line on a daily time step using station data with the highest possible spatial density. However, such a product is not available operationally and at an hourly discretisation. Therefore, we constructed an hourly gridded precipitation dataset at 1.44 km2 resolution for the Rhine basin for the period from 1998 to present using a REGNIE-like interpolation procedure (Weerts et al., 2008) using a low and a high density rain gauge network. The datasets were validated against daily HYRAS (Rauthe, 2013) and EOBS (Haylock, 2008) data. The main goal of the operational procedure is to emulate the HYRAS dataset as good as possible, as the daily HYRAS dataset is used in the off-line calibration of the hydrological model. Our main findings are that even with low station density, the spatial patterns found in the HYRAS data set are well reproduced. With low station density (years 1999-2006) our dataset underestimates precipitation compared to HYRAS and EOBS, notably during the winter. However, interpolation based on the same set of stations overestimates precipitation compared to EOBS for the years 2006-2014. This discrepancy disappears when switching to the high station density. We also analyze the robustness of the hourly precipitation fields by comparing with stations not used during interpolation. Specific issues regarding the data when creating the gridded precipitation fields will be highlighted. Finally, the datasets are used to drive an hourly and daily gridded WFLOW_HBV model of the Rhine at the same spatial resolution. Haylock, M.R., N. Hofstra, A.M.G. Klein Tank, E.J. Klok, P.D. Jones and M. New. 2008: A European daily high-resolution gridded dataset of surface temperature and

  19. Operations

    ERIC Educational Resources Information Center

    Wilkins, Jesse L. M.; Norton, Anderson; Boyce, Steven J.

    2013-01-01

    Previous research has documented schemes and operations that undergird students' understanding of fractions. This prior research was based, in large part, on small-group teaching experiments. However, written assessments are needed in order for teachers and researchers to assess students' ways of operating on a whole-class scale. In this study,…

  20. 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.

  1. Stable particles

    SciTech Connect

    Samios, N.P.

    1993-12-31

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc.

  2. Prognostic value of time-related changes of cardiopulmonary exercise testing indices in stable chronic heart failure: a pragmatic and operative scheme.

    PubMed

    Corrà, Ugo; Mezzani, Alessandro; Bosimini, Enzo; Giannuzzi, Pantaleo

    2006-04-01

    Although peak oxygen consumption (VO2) is an objective measurement of functional capacity linked to survival, most clinicians use clinical history to monitor changes over time of functional disability. The aim was to verify the prognostic value of time-related changes (Delta) of symptom-limited cardiopulmonary exercise testing (CPX) indices in stable chronic heart failure (CHF). We studied 231 stable CHF patients (200 men) with left ventricular ejection fraction (LVEF) of 24 +/- 8% and peak VO2 of 14.3 +/- 8 ml/kg per min, who performed two symptom-limited CPX over time. The two incremental CPX were separated by a mean interval of 258 +/- 42 days; 59 (26%) suffered cardiovascular death or underwent urgent heart transplantation during the follow-up (1167 +/- 562 days). Peak VO2, LVEF (measured at second evaluation), Deltapeak VO2 and DeltaNYHA (New York Heart Association classification) were selected as independent predictors in the total population, and LVEF, Deltapeak VO2, and NYHA in patients with peak VO2 of 14 ml/kg per min or less (106 patients); no Delta parameter was selected in patients with preserved exercise tolerance. Survival analysis was performed taking into consideration the inter-test variability of peak VO2 (6%): true fall: more than 6% decrease, decline within the measurement variability; less than 6% decrease, improvement within the measurement variability; less than 6% increase and true rise; more than 6% increase: total mortality rate was 51, 23, 19 and 14% (P < 0.0001), respectively. Deltapeak VO2 is a useful outcome index; a combination of static (single) and time-related functional variables can enhance the prognostication process in stable CHF patients.

  3. Stable Boundary Layer Education (STABLE) Final Campaign Summary

    SciTech Connect

    Turner, David D.

    2016-03-01

    The properties of, and the processes that occur in, the nocturnal stable boundary layer are not well understood, making it difficult to represent adequately in numerical models. The nocturnal boundary layer often is characterized by a temperature inversion and, in the Southern Great Plains region, a low-level jet. To advance our understanding of the nocturnal stable boundary layer, high temporal and vertical resolution data on the temperature and wind properties are needed, along with both large-eddy simulation and cloud-resolving modeling.

  4. Studies and optimization of Pohang Light Source-II superconducting radio frequency system at stable top-up operation with beam current of 400 mA

    SciTech Connect

    Joo, Youngdo Yu, Inha; Park, Insoo; Chun, Myunghwan; Lee, Byung-Joon; Hwang, Ilmoon; Ha, Taekyun; Shin, Seunghwan; Sohn, Younguk

    2014-12-21

    After three years of upgrading work, the Pohang Light Source-II (PLS-II) is now successfully operating. The final quantitative goal of PLS-II is a top-up user-service operation with beam current of 400 mA to be completed by the end of 2014. During the beam store test up to 400 mA in the storage ring (SR), it was observed that the vacuum pressure around the radio frequency (RF) window of the superconducting cavity rapidly increases over the interlock level limiting the availability of the maximum beam current storing. Although available beam current is enhanced by setting a higher RF accelerating voltage, it is better to keep the RF accelerating voltage as low as possible in the long time top-up operation. We investigated the cause of the window vacuum pressure increment by studying the changes in the electric field distribution at the superconducting cavity and waveguide according to the beam current. In our simulation, an equivalent physical modeling was developed using a finite-difference time-domain code. The simulation revealed that the electric field amplitude at the RF window is exponentially increased as the beam current increases, thus this high electric field amplitude causes a RF breakdown at the RF window, which comes with the rapid increase of window vacuum pressure. The RF accelerating voltage of PLS-II RF system was set to 4.95 MV, which was estimated using the maximum available beam current that works as a function of RF voltage, and the top-up operation test with the beam current of 400 mA was successfully carried out.

  5. Implementation and Operational Research: Community-Based Adherence Clubs for the Management of Stable Antiretroviral Therapy Patients in Cape Town, South Africa: A Cohort Study.

    PubMed

    Grimsrud, Anna; Lesosky, Maia; Kalombo, Cathy; Bekker, Linda-Gail; Myer, Landon

    2016-01-01

    Community-based models of antiretroviral therapy (ART) delivery are widely discussed as a priority in the expansion of HIV treatment services, but data on their effectiveness are limited. We examined outcomes of ART patients decentralized to community-based adherence clubs (CACs) in Cape Town, South Africa and compared these to patients managed in the community health center. The analysis included 8150 adults initiating ART from 2002 to 2012 in a public sector service followed until the end of 2013. From June 2012, stable patients (on ART >12 months, suppressed viral load) were referred to CACs. Loss to follow-up (LTFU) was compared between services using proportional hazards models with time-varying covariates and inverse probability weights of CAC participation. Of the 2113 CAC patients (71% female, 7% youth ages ≤ 24 years), 94% were retained on ART after 12 months. Among CAC patients, LTFU [adjusted hazard ratio (aHR): 2.17, 95% confidence interval (CI): 1.26 to 3.73 ] and viral rebound (aHR 2.24, 95% CI: 1.00 to 5.04) were twice as likely in youth (16-24 years old) compared with older patients, but no difference in the risk of LTFU or viral rebound was observed by sex (P-values 0.613 and 0.278, respectively). CAC participation was associated with a 67% reduction in the risk of LTFU (aHR: 0.33, 95% CI: 0.27 to 0.40) compared with community health centre, and this association persisted when stratified by patient demographic and clinic characteristics. CACs are associated with reduced risk of LTFU compared with facility-based care. Community-based models represent an important development to facilitate ART delivery and possibly improve patient outcomes.

  6. Analysis of the sensitivity to rainfall spatio-temporal variability of an operational urban rainfall-runoff model in a multifractal framework

    NASA Astrophysics Data System (ADS)

    Gires, A.; Tchiguirinskaia, I.; Schertzer, D. J.; Lovejoy, S.

    2011-12-01

    In large urban areas, storm water management is a challenge with enlarging impervious areas. Many cities have implemented real time control (RTC) of their urban drainage system to either reduce overflow or limit urban contamination. A basic component of RTC is hydraulic/hydrologic model. In this paper we use the multifractal framework to suggest an innovative way to test the sensitivity of such a model to the spatio-temporal variability of its rainfall input. Indeed the rainfall variability is often neglected in urban context, being considered as a non-relevant issue at the scales involve. Our results show that on the contrary the rainfall variability should be taken into account. Universal multifractals (UM) rely on the concept of multiplicative cascade and are a standard tool to analyze and simulate with a reduced number of parameters geophysical processes that are extremely variable over a wide range of scales. This study is conducted on a 3 400 ha urban area located in Seine-Saint-Denis, in the North of Paris (France). We use the operational semi-distributed model that was calibrated by the local authority (Direction Eau et Assainnissement du 93) that is in charge of urban drainage. The rainfall data comes from the C-Band radar of Trappes operated by Météo-France. The rainfall event of February 9th, 2009 was used. A stochastic ensemble approach was implemented to quantify the uncertainty on discharge associated to the rainfall variability occurring at scales smaller than 1 km x 1 km x 5 min that is usually available with C-band radar networks. An analysis of the quantiles of the simulated peak flow showed that the uncertainty exceeds 20 % for upstream links. To evaluate a potential gain from a direct use of the rainfall data available at the resolution of X-band radar, we performed similar analysis of the rainfall fields of the degraded resolution of 9 km x 9 km x 20 min. The results show a clear decrease in uncertainty when the original resolution of C

  7. Mechanisms for detecting auditory temporal and spectral deviations operate over similar time windows but are divided differently between the two hemispheres.

    PubMed

    Grimm, Sabine; Roeber, Urte; Trujillo-Barreto, Nelson J; Schröger, Erich

    2006-08-01

    In order to keep track of potentially relevant information in the acoustic environment, the human brain processes sounds to a high extent even when they are not attended: it extracts basic features, encodes regularities, and detects deviances. Here, we deliver evidence that the initial 300 ms of a sound contribute more to this preattentive processing than the sound's later parts. We directly compared the influence of the temporal distance relative to sound onset on the processing of the sound's duration and frequency information. The mismatch negativity (MMN), an event-related potential indicator for preattentive feature encoding and deviance detection, was measured for infrequent duration deviants and frequency modulation deviants. The onset of either deviancy was at 100, 200, 300, or 400 ms relative to sound onset. MMN was only elicited for deviations occurring within the first 300 ms after sound onset for both types of deviants. Its neural sources were localized in supra-temporal cortices with source current density analyses (SCD) and variable resolution electromagnetic tomography (VARETA), revealing a right-hemispheric preponderance for frequency modulations but not for duration shortenings. This suggests that preattentive deviance detection is based upon partly diverging functional memory registers for temporal and dynamic spectral information. The influence of temporal distance on MMN in both conditions supports the view that temporal and spectral sound properties are integrated into an auditory object representation prior to preattentive deviance detection. Importantly, the decline of MMN to unattended sounds with larger temporal distance suggests that parts beyond 300 ms are less important for preattentive auditory object representation.

  8. Highly stable and efficient erbium-doped 2.8 microm all fiber laser.

    PubMed

    Bernier, Martin; Faucher, Dominic; Caron, Nicolas; Vallée, Réal

    2009-09-14

    We demonstrate the efficient and stable CW laser operation at 2.824 microm of a diode-pumped erbium-doped fluoride fiber laser employing an intracore fiber Bragg grating high reflector. An output power of 5 W and an optical-to-optical conversion efficiency of 32% are reported. The temporal and spectral stability of the laser represent a significant improvement over previous work. This report paves the way to the commercialization of compact and stable fiber lasers for spectroscopic and medical applications.

  9. Temporal properties of stereopsis

    NASA Astrophysics Data System (ADS)

    Gheorghiu, E.

    2005-03-01

    The goal of the research presented in this thesis was to investigate temporal properties of disparity processing and depth perception in human subjects, in response to dynamic stimuli. The results presented in various chapters, reporting findings about different temporal aspects of disparity processing, are based on psychophysical experiments and computational model analysis. In chapter 1 we investigated which processes of binocular depth perception in dynamic random-dot stereograms (DRS), i.e., tolerance for interocular delays and temporal integration of correlation, are responsible for the temporal flexibility of the stereoscopic system. Our results demonstrate that (i) disparities from simultaneous monocular inputs dominate those from interocular delayed inputs; (ii) stereopsis is limited by temporal properties of monocular luminance mechanisms; (iii) depth perception in DRS results from cross-correlation-like operation on two simultaneous monocular inputs that represent the retinal images after having been subjected to a process of monocular temporal integration of luminance. In chapter 2 we examined what temporal information is exploited by the mechanisms underlying stereoscopic motion in depth. We investigated systematically the influence of temporal frequency on binocular depth perception in temporally correlated and temporally uncorrelated DRS. Our results show that disparity-defined depth is judged differently in temporally correlated and uncorrelated DRS above a temporal frequency of about 3 Hz. The results and simulations indicate that: (i) above about 20 Hz, the complete absence of stereomotion is caused by temporal integration of luminance; (ii) the difference in perceived depth in temporally correlated and temporally uncorrelated DRS for temporal frequencies between 20 and 3 Hz, is caused by temporal integration of disparity. In chapter 3 we investigated temporal properties of stereopsis at different spatial scales in response to sustained and

  10. Impact of Phlebotomine Sand Flies on U.S. Military Operations at Tallil Air Base, Iraq: 2. Temporal and Geographic Distribution of Sand Flies

    DTIC Science & Technology

    2007-01-01

    collections, with StudentÐNewmanÐ Keuls test (P 0.05) used to separate mean values. Results TemporalDistribution of Phlebotomine SandFlies at Tallil...each. DielActivity of SandFlies atTallilAirBase. In total, 2,574 phlebotomine sand ßies was collected during 25 trap nights between 6 May 2003 and 30... SandFlies InsideTents at TAB.This studywas conducted between 25May and 30October 2003. Ninety-Þve replicates were conducted in tents that had no air

  11. Stable Fly Research

    USDA-ARS?s Scientific Manuscript database

    Adult stable flies feed on the blood of humans, pets and livestock, inflicting painful bites. Stable flies need one and sometimes two bloodmeals each day to develop their eggs. Unlike mosquitoes where only the females bloodfeed, both male and female stable flies require blood to reproduce. Stable fl...

  12. 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

  13. Investigation of spatio-temporal variability of water uptake in a groundwater-dependent ecosystem using a stable isotope approach (δ18O, δ2H): Pfyn Forest, Switzerland

    NASA Astrophysics Data System (ADS)

    Bertrand, G.; Masini, J.; Goldscheider, N.; Gobat, J. M.; Hunkeler, D.

    2012-04-01

    total humidity of soil, this could be due to rapid infiltration and/or fractionation mainly under equilibrium, i.e. with a relatively high atmospheric humidity, what is possible under forest canopy. Plant water is located under the LMWL in September 2010 when the soil was relatively drought. This evaporative signature could be a clue of water stress. More investigations are however needed to check if this parameter can be used routinely to address water stress. - Secondly, through an analysis of variance, data reveal that at the ecosystem scale, water uptake depends on the site (type of soil, surrounding vegetation, distance from the river), on the growing status (non growing, flowering, mature, water stress) and on the species (poplar, willow, alder, pine). - At last, when focusing at the temporal variability for some individuals, it appears that both rainwater and groundwater may participate to water uptake. The water uptake patterns seem more complicated in mature areas (far from the riverbed) than in frequently flooded zones. This could be due to a more complex soil texture patchwork in the former, and a globally finer soil texture. In particular, it appears that groundwater may sometimes replace rainwater through capillary rise during warm periods.

  14. Magnetotelluric Data, Stable Distributions and Stable Regression

    NASA Astrophysics Data System (ADS)

    Chave, A. D.

    2013-12-01

    The author has noted for many years that the residuals from robust or bounded influence estimates of the magnetotelluric response function are systematically long tailed compared to a Gaussian or Rayleigh distribution. Consequently, the standard statistical model of a Gaussian core contaminated by a fraction of outlying data is not really valid. However, the typical result is an improvement on ordinary least squares, and has become standard in the electromagnetic induction community. A recent re-evaluation of the statistics of magnetotelluric response function estimation has shown that, in almost all cases, the residuals are alpha stable rather than Gaussian. Alpha stable distributions are characterized by four parameters: a shape parameter lying on (0, 2], a skewness parameter, a scale parameter and a location parameter, and cannot be expressed in closed form except for a few special cases. When the shape parameter is 2, the result is Gaussian, but when it is smaller the resulting distribution has infinite variance. Typical magnetotelluric residuals are alpha stable with a shape parameter lying between 1 and 2. This suggests that robust methods improve response function estimates by eliminating data corresponding to the largest stable residuals while leaving the bulk of the population alone. A better statistical approach is based on stable regression that directly accommodates the actual residual distribution without eliminating the most extreme ones. This paper will introduce such an algorithm, and illustrate its functionality with a variety of magnetotelluric data. Further work remains to produce a robust stable regression algorithm that will eliminate real outliers such as lightning strikes or instrument problems without affecting the bulk stable population. Stable distributions are intimately associated with fractional derivative physical processes. Since the Maxwell equations and the constitutive relations pertaining to the earth do not contain any fractional

  15. Responses of spatial-temporal dynamics of bacterioplankton community to large-scale reservoir operation: a case study in the Three Gorges Reservoir, China

    PubMed Central

    Li, Zhe; Lu, Lunhui; Guo, Jinsong; Yang, Jixiang; Zhang, Jiachao; He, Bin; Xu, Linlin

    2017-01-01

    Large rivers are commonly regulated by damming, yet the effects of such disruption on bacterioplankton community structures have not been adequately studied. The aim of this study was to explore the biogeographical patterns present under dam regulation and to uncover the major drivers structuring bacterioplankton communities. Bacterioplankton assemblages in the Three Gorges Reservoir (TGR) were analyzed using Illumina Miseq sequencing by comparing seven sites located within the TGR before and after impoundment. This approach revealed ecological and spatial-temporal variations in bacterioplankton community composition along the longitudinal axis. The community was dynamic and dominated by Proteobacteria and Actinobacteria phyla, encompassing 39.26% and 37.14% of all sequences, respectively, followed by Bacteroidetes (8.67%) and Cyanobacteria (3.90%). The Shannon-Wiener index of the bacterioplankton community in the flood season (August) was generally higher than that in the impoundment season (November). Principal Component Analysis of the bacterioplankton community compositions showed separation between different seasons and sampling sites. Results of the relationship between bacterioplankton community compositions and environmental variables highlighted that ecological processes of element cycling and large dam disturbances are of prime importance in driving the assemblages of riverine bacterioplankton communities. PMID:28211884

  16. Angina Pectoris (Stable Angina)

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Angina Pectoris (Stable Angina) Updated:Sep 19,2016 You may have heard the term “angina pectoris” or “stable angina” in your doctor’s office, but ...

  17. Impact of phlebotomine sand flies on U.S. Military operations at Tallil Air Base, Iraq: 2. Temporal and geographic distribution of sand flies.

    PubMed

    Coleman, Russell E; Burkett, Douglas A; Sherwood, Van; Caci, Jennifer; Spradling, Sharon; Jennings, Barton T; Rowton, Edgar; Gilmore, Wayne; Blount, Keith; White, Charles E; Putnam, John L

    2007-01-01

    CDC miniature light traps were used to evaluate the general biology of phlebotomine sand flies from April 2003 to November 2004 at Tallil Air Base, Iraq. Factors evaluated include species diversity and temporal (daily and seasonal) and geographic distribution of the sand flies. In addition, the abundance of sand flies inside and outside tents and buildings was observed. In total, 61,630 sand flies were collected during 1,174 trap nights (mean 52 per trap, range 0-1,161), with 90% of traps containing sand flies. Sand fly numbers were low in April, rose through May, were highest from mid-June to early September, and dropped rapidly in late September and October. More than 70% of the sand flies were female, and of these sand flies, 8% contained visible blood. Phlebotomus alexandri Sinton, Phlebotomus papatasi Scopoli, Phlebotomus sergenti Parrot, and Sergentomyia spp. accounted for 30, 24, 1, and 45% of the sand flies that were identified, respectively. P. alexandri was more abundant earlier in the season (April and May) than P. papatasi, whereas P. papatasi predominated later in the season (August and September). Studies on the nocturnal activity of sand flies indicated that they were most active early in the evening during the cooler months, whereas they were more active in the middle of the night during the hotter months. Light traps placed inside tents with and without air conditioners collected 83 and 70% fewer sand flies, respectively, than did light traps placed outside the tents. The implications of these findings to Leishmania transmission in the vicinity of Tallil Air Base are discussed.

  18. Spatio-temporal variations of carbon dioxide and its gross emission regulated by artificial operation in a typical hydropower reservoir in China.

    PubMed

    Li, Zhe; Zhang, Zengyu; Xiao, Yan; Guo, Jinsong; Wu, Shengjun; Liu, Jing

    2014-05-01

    Supersaturation and excess emission of greenhouse gases in freshwater reservoirs have received a great deal of attention in recent years. Although impoundment of reservoirs has been shown to contribute to the net emission of greenhouse gases, reservoir age, geographical distribution, submerged soil type and artificial regulation also have a great impact on their emissions. To examine how large scale reservoir operation impact the water column CO2 and its air-water interface flux, a field study was conducted in 2010 to evaluate potential ecological processes that regulate the partial pressure of CO2 (pCO2) in the water column in the Pengxi River backwater area (PBA), a typical tributary in the Three Gorges Reservoir, China. Measurements of total alkalinity (TA), pH and water temperature were applied to compute the pCO2. And this approach was also validated by calculation of pCO2 from the dissolved inorganic carbon data of samples. Partial least squares (PLS) regression was used to determine how the dynamics of the water pCO2 were related to the available variables. The estimated pCO2 in our sample ranged from 26 to 4,087 μatm in the surface water. During low water operation from July to early September, there was an obvious pCO2 stratification, and pCO2 in the surface was almost unsaturated. This phenomenon was also observed in the spring bloom during discharge period. Conversely, there was no significant pCO2 stratification and the entire water column was supersaturated during high water operation from November to the following February. Significant correlation was observed between the magnitude of pCO2, DO and chlorophyll a, suggesting that phytoplankton dynamics regulate pCO2 in the PBA. The average areal rate of CO2 emissions from the Pengxi River ranged from 18.06 to 48.09 mmol m(-2) day(-1), with an estimated gross CO2 emission from the water surface of 14-37 t day(-1) in this area in 2010. Photosynthesis and respiration rates by phytoplankton might be the

  19. INVERSE STABLE SUBORDINATORS

    PubMed Central

    MEERSCHAERT, MARK M.; STRAKA, PETER

    2013-01-01

    The inverse stable subordinator provides a probability model for time-fractional differential equations, and leads to explicit solution formulae. This paper reviews properties of the inverse stable subordinator, and applications to a variety of problems in mathematics and physics. Several different governing equations for the inverse stable subordinator have been proposed in the literature. This paper also shows how these equations can be reconciled. PMID:25045216

  20. Stable Gain-Switched Thulium Fiber Laser With 140-nm Tuning Range

    NASA Astrophysics Data System (ADS)

    Wang, Fengqiu; Meng, Yafei; Kelleher, Edmund; Guo, Guoxiang; Li, Yao; Xu, Yongbing; Zhu, Shining

    2016-06-01

    We demonstrate a gain-switched thulium fiber laser that can be continuously tuned over 140 nm, while maintaining stable nanosecond single-pulse operation. To the best of our knowledge, this system represents the broadest tuning range for a gain-switched fiber laser. The system simplicity and wideband wavelength tunability combined with the ability to control the temporal characteristics of the gain-switched pulses mean this is a versatile source highly suited to a wide range of applications in the eye-safe region of the infrared, including spectroscopy, sensing and material processing, as well as being a practical seed source for pumping nonlinear processes.

  1. 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.

  2. Stable isotope laser spectroscopy

    NASA Technical Reports Server (NTRS)

    Becker, J. F.; Yaldaei, Ramil; Mckay, Christopher P.

    1989-01-01

    Recent advances in semiconductor laser technology have produced a reliable lightweight device ideally suited for a spacecraft high resolution molecular spectrometer. Lead-salt tunable diode lasers (TDL) emit in several spectral modes, each with a very narrow linewidth of -0.0003/cm. This spectral resolution is much narrower than typical Doppler broadened molecular linewidths in the mid-IR range. Thus it is possible to detect individual rotational lines within the vibrational band and measure their intensity, which can be used to determine gas concentration. The narrow spectral lines of any impurity gas tend to lie between the narrow lines of the gas of interest. This represents a major advantage over the accepted gas chromatograph mass spectrometer (GCMS) technique for measuring gas concentrations and isotope ratios. The careful and extensive gas purification procedures required to remove impurities for reliable GCMS measurements will not be required for an IR laser gas analysis. The infrared laser gas analysis technique is being developed to measure stable isotopic ratios of gases such as CO2, CH4, N2O, and NH3. This will eventually lead to development of instruments capable of in situ istopic measurements on planets such as Mars. The carbon (C-12, C-13) isotope ratio is indicative of the type of carbon fixation mechanisms (e.g., photosynthesis, respiration) in operation on a planet, while the nitrogen (N-14, N-15) isotope ratio can probably be used to date nitrogen-bearing Martian samples. The absorbance ratio of two adjacent lines of CO2 in the 2300/cm (4.3 micron) region of the spectrum was measured. The precision of the measurement is presently better than 1 percent and significant improvement is anticipated as rapid sweep-integration techniques and computer controlled data acquistion capabilities are incorporated.

  3. Unstable neurons underlie a stable learned behavior

    PubMed Central

    Liberti, William A.; Markowitz, Jeffrey E.; Perkins, L. Nathan; Liberti, Derek C.; Leman, Daniel P.; Guitchounts, Grigori; Velho, Tarciso; Kotton, Darrell N.; Lois, Carlos; Gardner, Timothy J.

    2016-01-01

    Motor skills can be maintained for decades, but the biological basis of this memory persistence remains largely unknown. The zebra finch, for example, sings a highly stereotyped song that is stable for years, but it is not known whether the precise neural patterns underlying song are stable or shift from day to day. Here, we demonstrate that the population of projection neurons coding for song in the pre-motor nucleus HVC change from day to day. The most dramatic shifts occur over intervals of sleep. In contrast to the transient participation of excitatory neurons, ensemble measurements dominated by inhibition persist unchanged even after damage to downstream motor nerves. These observations offer a principle of motor stability: spatio-temporal patterns of inhibition can maintain a stable scaffold for motor dynamics while the population of principle neurons that directly drive behavior shift from one day to the next. PMID:27723744

  4. Overview and first results from project STABLE (STAble Boundary Layer Experiment)

    SciTech Connect

    Weber, A.H.; Kurzeja, R.J.

    1988-01-01

    The STABLE project (STAble Boundary Layer Experiment) is a multiyear research effort conceived in 1984 by the Savannah River Laboratory (SRL) and planned by several research groups to study turbulence and diffusion in the stable boundary layer (SBL). The program was jointly planned by Department of Energy (DOE) affiliated laboratories and universities including SRL, Atmospheric Turbulence and Diffusion Division (ATDD) of the National Oceanic and Atmospheric Administration (NOAA), Argonne National Laboratory (ANL), North Carolina State University (NCSU), and The Pennsylvania State University. STABLE's goals are to determine the spatial and temporal distribution of turbulent events during the nighttime, to determine the validity of present models and theories in describing the structure and evolution of the SBL, to determine the role of waves and intermittent turbulence in dispersing chemicals, and to determine better parameterization for describing the mean state and intermittent events in the SBL. By taking advantage of special facility, the program seeks to economize effort and cost. 1 ref., 7 figs.

  5. Chondroblastoma of the Temporal Bone

    PubMed Central

    Selesnick, Samuel H.; Levine, Jennifer M.

    1999-01-01

    The objective of this study is to describe the presentation and clinical course of two patients with temporal bone chondroblastoma, and to review the literature on temporal bone chondroblastoma to identify characteristic clinical and radiological presentations, and optimal treatment regimens. MEDLINE literature searches covering the period from 1966 to January 1998, in all languages, were performed as well as a review of the bibliographies of the identified studies. Strict inclusion criteria were upheld, In total 18 studies had patients whose data could be analyzed. From the 18 studies, 34 patients were identified, but only 21 cases met the inclusion criteria. Demographic, clinical presentation, radiological, operative and treatment parameters were analyzed in this cohort of patients. Ninety-five percent of patients were found to have invasion of the middle cranial fossa and 76% were found to have erosion into the superior aspect of the external auditory canal by temporal bone chondroblastoma. The characteristic growth pattern of temporal bone chondroblastoma may result from embryonal or cartilagenous rests entrapped in the tympanosquamous suture line in the middle fossa floor. Temporal bone chondroblastoma represents a pathology that does not arise from, or have a growth pattern resembling other pathologies in the temporal bone. ImagesFigure 1Figure 2 PMID:17171120

  6. A stable argon compound

    PubMed

    Khriachtchev; Pettersson; Runeberg; Lundell; Rasanen

    2000-08-24

    The noble gases have a particularly stable electronic configuration, comprising fully filled s and p valence orbitals. This makes these elements relatively non-reactive, and they exist at room temperature as monatomic gases. Pauling predicted in 1933 that the heavier noble gases, whose valence electrons are screened by core electrons and thus less strongly bound, could form stable molecules. This prediction was verified in 1962 by the preparation of xenon hexafluoroplatinate, XePtF6, the first compound to contain a noble-gas atom. Since then, a range of different compounds containing radon, xenon and krypton have been theoretically anticipated and prepared. Although the lighter noble gases neon, helium and argon are also expected to be reactive under suitable conditions, they remain the last three long-lived elements of the periodic table for which no stable compound is known. Here we report that the photolysis of hydrogen fluoride in a solid argon matrix leads to the formation of argon fluorohydride (HArF), which we have identified by probing the shift in the position of vibrational bands on isotopic substitution using infrared spectroscopy. Extensive ab initio calculations indicate that HArF is intrinsically stable, owing to significant ionic and covalent contributions to its bonding, thus confirming computational predictions that argon should form a stable hydride species with properties similar to those of the analogous xenon and krypton compounds reported before.

  7. Efficient Methods for Stable Distributions

    DTIC Science & Technology

    2007-11-02

    are used, corresponding to the common values used in digital signal processing. Five new functions for discrete/quantized stable distributions were...written. • sgendiscrete generates discrete stable random variates. It works by generating continuous stable random variables using the Chambers- Mallows ...with stable distributions. It allows engineers and scientists to analyze data and work with stable distributions within the common matlab environment

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

    SciTech Connect

    Lee, Jinsik; Jang, Gilsoo; Muljadi, Eduard; Blaabjerg, Frede; Chen, Zhe; Cheol Kang, Yong

    2016-09-01

    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 during 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.

  9. 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.

  10. Time, Temporality, Now

    NASA Astrophysics Data System (ADS)

    Atmanspacher, Harald; Ruhnau, Eva

    The essays in this topical volume inquire into one of the most fundamental issues of philosophy and of the cognitive and natural sciences: the riddle of time. The central feature is the tension between the experience and the conceptualization of time, reflecting an apparently unavoidable antinomy of subjective first-person accounts and objective traditional science. Is time based in the physics of inanimate matter, or does it originate in the operation of our minds? Is it essential for the constitution of reality, or is it just an illusion? Issues of time, temporality, and nowness are paradigms for interdisciplinary work in many contemporary fields of research. The authors of this volume discuss profoundly the mutual relationships and inspiring perspectives. They address a general audience.

  11. The Stable Pairing Problem

    ERIC Educational Resources Information Center

    Greenwell, Raymond N.; Seabold, Daniel E.

    2014-01-01

    The Gale-Shapley stable marriage theorem is a fascinating piece of twentieth-century mathematics that has many practical applications--from labor markets to school admissions--yet is accessible to secondary school mathematics students. David Gale and Lloyd Shapley were both mathematicians and economists who published their work on the Stable…

  12. The Stable Pairing Problem

    ERIC Educational Resources Information Center

    Greenwell, Raymond N.; Seabold, Daniel E.

    2014-01-01

    The Gale-Shapley stable marriage theorem is a fascinating piece of twentieth-century mathematics that has many practical applications--from labor markets to school admissions--yet is accessible to secondary school mathematics students. David Gale and Lloyd Shapley were both mathematicians and economists who published their work on the Stable…

  13. Stable unstable reliability theory.

    PubMed

    Thomas, Hoben; Lohaus, Arnold; Domsch, Holger

    2012-05-01

    Classical reliability theory assumes that individuals have identical true scores on both testing occasions, a condition described as stable. If some individuals' true scores are different on different testing occasions, described as unstable, the estimated reliability can be misleading. A model called stable unstable reliability theory (SURT) frames stability or instability as an empirically testable question. SURT assumes a mixed population of stable and unstable individuals in unknown proportions, with w(i) the probability that individual i is stable. w(i) becomes i's test score weight which is used to form a weighted correlation coefficient r(w) which is reliability under SURT. If all w(i) = 1 then r(w) is the classical reliability coefficient; thus classical theory is a special case of SURT. Typically r(w) is larger than the conventional reliability r, and confidence intervals on true scores are typically shorter than conventional intervals. r(w) is computed with routines in a publicly available R package. ©2011 The British Psychological Society.

  14. 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.

  15. Vestibular Schwannoma Atypically Invading Temporal Bone

    PubMed Central

    Park, Soo Jeong; Yang, Na-Rae

    2015-01-01

    Vestibular schwannoma (VS) usually present the widening of internal auditory canal (IAC), and these bony changes are typically limited to IAC, not extend to temporal bone. Temporal bone invasion by VS is extremely rare. We report 51-year-old man who revealed temporal bone destruction beyond IAC by unilateral VS. The bony destruction extended anteriorly to the carotid canal and inferiorly to the jugular foramen. On histopathologic examination, the tumor showed typical benign schwannoma and did not show any unusual vascularity or malignant feature. Facial nerve was severely compressed and distorted by tumor, which unevenly eroded temporal bone in surgical field. Vestibular schwannoma with atypical invasion of temporal bone can be successfully treated with combined translabyrinthine and lateral suboccipiral approach without facial nerve dysfunction. Early detection and careful dissection of facial nerve with intraoperative monitoring should be considered during operation due to severe adhesion and distortion of facial nerve by tumor and eroded temporal bone. PMID:25932298

  16. A stable gain-switched Ho:CYA laser resonantly pumped at 1922 nm

    NASA Astrophysics Data System (ADS)

    Zhang, J. N.; Chen, B. H.; Shen, D. Y.; Xu, X. D.

    2017-04-01

    We report on a gain-switched Ho:CaYAlO4 laser resonantly pumped by a home-constructed high power Tm:fiber laser at ~1922 nm. Stable nanosecond single-pulse operation could be maintained when the continuous-wave pump signal was modulated at repetition rates of 60–100 kHz with an acousto-optic modulator. A pulse duration of 311 ns has been obtained at a 60 kHz repetition rate under a pump power level of 11 W. The temporal stability and simplicity of operation make this laser suitable for a variety of applications, such as spectroscopy, gas sensing, and as the seed source of a master oscillation power amplifier system.

  17. Implementation and Operational Research: CD4 Count Monitoring Frequency and Risk of CD4 Count Dropping Below 200 Cells Per Cubic Millimeter Among Stable HIV-Infected Patients in New York City, 2007-2013.

    PubMed

    Myers, Julie E; Xia, Qiang; Torian, Lucia V; Irvine, Mary; Harriman, Graham; Sepkowitz, Kent A; Shepard, Colin W

    2016-03-01

    The evidence has begun to mount for diminishing the frequency of CD4 count testing. To determine whether these observations were applicable to an urban US population, we used New York City (NYC) surveillance data to explore CD4 testing among stable patients in NYC, 2007-2013. We constructed a population-based retrospective open cohort analysis of NYC HIV surveillance data. HIV+ patients aged ≥ 13 years with stable viral suppression (≥ 1 viral load the previous year; all <400 copies per milliliter) and immune status (≥ 1 CD4 the previous year; all ≥ 200 cells per cubic millimeter) entered the cohort the following year beginning January 1, 2007. Each subsequent year, eligible patients not previously included entered the cohort on January 1. Outcomes were annual frequency of CD4 monitoring and probability of maintaining CD4 ≥ 200 cells per cubic millimeter. A multivariable Cox model identified factors associated with maintaining CD4 ≥ 200 cells per cubic millimeter. During 1.9 years of observation (median), 62,039 patients entered the cohort. The mean annual number of CD4 measurements among stable patients was 2.8 and varied little by year or characteristic. Two years after entering, 93.4% and 97.8% of those with initial CD4 350-499 and CD4 ≥ 500 cells per cubic millimeter, respectively, maintained CD4 ≥ 200 cells per cubic millimeter. Compared to those with initial CD4 ≥ 500 cells per cubic millimeter, those with CD4 200-349 cells per cubic millimeter and CD4 350-499 cells per cubic millimeter were more likely to have a CD4 <200 cells per cubic millimeter, controlling for sex, race, age, HIV risk group, and diagnosis year. In a population-based US cohort with well-controlled HIV, the probability of maintaining CD4 ≥ 200 cells per cubic millimeter for ≥ 2 years was >90% among those with initial CD4 ≥ 350 cells per cubic millimeter, suggesting that limited CD4 monitoring in these patients is appropriate.

  18. Implementation and Operational Research: CD4 Count Monitoring Frequency and Risk of CD4 Count Dropping Below 200 Cells Per Cubic Millimeter Among Stable HIV-Infected Patients in New York City, 2007–2013

    PubMed Central

    Xia, Qiang; Torian, Lucia V.; Irvine, Mary; Harriman, Graham; Sepkowitz, Kent A.; Shepard, Colin W.

    2016-01-01

    Introduction: The evidence has begun to mount for diminishing the frequency of CD4 count testing. To determine whether these observations were applicable to an urban US population, we used New York City (NYC) surveillance data to explore CD4 testing among stable patients in NYC, 2007–2013. Methods: We constructed a population-based retrospective open cohort analysis of NYC HIV surveillance data. HIV+ patients aged ≥13 years with stable viral suppression (≥1 viral load the previous year; all <400 copies per milliliter) and immune status (≥1 CD4 the previous year; all ≥200 cells per cubic millimeter) entered the cohort the following year beginning January 1, 2007. Each subsequent year, eligible patients not previously included entered the cohort on January 1. Outcomes were annual frequency of CD4 monitoring and probability of maintaining CD4 ≥200 cells per cubic millimeter. A multivariable Cox model identified factors associated with maintaining CD4 ≥200 cells per cubic millimeter. Results: During 1.9 years of observation (median), 62,039 patients entered the cohort. The mean annual number of CD4 measurements among stable patients was 2.8 and varied little by year or characteristic. Two years after entering, 93.4% and 97.8% of those with initial CD4 350–499 and CD4 ≥500 cells per cubic millimeter, respectively, maintained CD4 ≥200 cells per cubic millimeter. Compared to those with initial CD4 ≥500 cells per cubic millimeter, those with CD4 200–349 cells per cubic millimeter and CD4 350–499 cells per cubic millimeter were more likely to have a CD4 <200 cells per cubic millimeter, controlling for sex, race, age, HIV risk group, and diagnosis year. Conclusions: In a population-based US cohort with well-controlled HIV, the probability of maintaining CD4 ≥200 cells per cubic millimeter for ≥2 years was >90% among those with initial CD4 ≥350 cells per cubic millimeter, suggesting that limited CD4 monitoring in these patients is appropriate

  19. Stable glow discharge detector

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2004-05-18

    A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) stable glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The stable glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma and a solid rod electrode. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured. The solid rod electrode provides greater stability and thus easier alignment.

  20. Stable isotopes in mineralogy

    USGS Publications Warehouse

    O'Neil, J.R.

    1977-01-01

    Stable isotope fractionations between minerals are functions of the fundamental vibrational frequencies of the minerals and therefore bear on several topics of mineralogical interest. Isotopic compositions of the elements H, C, O, Si, and S can now be determined routinely in almost any mineral. A summary has been made of both published and new results of laboratory investigations, analyses of natural materials, and theoretical considerations which bear on the importance of temperature, pressure, chemical composition and crystal structure to the isotopic properties of minerals. It is shown that stable isotope studies can sometimes provide evidence for elucidating details of crystal structure and can be a powerful tool for use in tracing the reaction paths of mineralogical reactions. ?? 1977 Springer-Verlag.

  1. Stable local oscillator module.

    SciTech Connect

    Brocato, Robert Wesley

    2007-11-01

    This report gives a description of the development of a Stable Local Oscillator (StaLO) multi-chip module (MCM). It is a follow-on report to SAND2006-6414, Stable Local Oscillator Microcircuit. The StaLO accepts a 100MHz input signal and produces output signals at 1.2, 3.3, and 3.6 GHz. The circuit is built as a multi-chip module (MCM), since it makes use of integrated circuit technologies in silicon and lithium niobate as well as discrete passive components. This report describes the development of an MCM-based version of the complete StaLO, fabricated on an alumina thick film hybrid substrate.

  2. Stable Charged Cosmic Strings

    SciTech Connect

    Weigel, H.; Quandt, M.; Graham, N.

    2011-03-11

    We study the quantum stabilization of a cosmic string by a heavy fermion doublet in a reduced version of the standard model. We show that charged strings, obtained by populating fermionic bound state levels, become stable if the electroweak bosons are coupled to a fermion that is less than twice as heavy as the top quark. This result suggests that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model. Numerically we find the most favorable string profile to be a simple trough in the Higgs vacuum expectation value of radius {approx_equal}10{sup -18} m. The vacuum remains stable in our model, because neutral strings are not energetically favored.

  3. Stable charged cosmic strings.

    PubMed

    Weigel, H; Quandt, M; Graham, N

    2011-03-11

    We study the quantum stabilization of a cosmic string by a heavy fermion doublet in a reduced version of the standard model. We show that charged strings, obtained by populating fermionic bound state levels, become stable if the electroweak bosons are coupled to a fermion that is less than twice as heavy as the top quark. This result suggests that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model. Numerically we find the most favorable string profile to be a simple trough in the Higgs vacuum expectation value of radius ≈10(-18)  m. The vacuum remains stable in our model, because neutral strings are not energetically favored.

  4. Handbook of stable strontium

    SciTech Connect

    Skoryna, S.C.

    1981-01-01

    This book presents information on the following topics: chemistry of strontium; biogeochemistry of strontium; uptake of stable strontium by plants and effects on plant growth; divalent cation-dependent deposits in paramecium; effects of strontium ion on the hydrolysis of ATP; stronium ions and membranes - screening versus binding at charged surfaces; mitochondrial granules in the liver of rats kept on stable strontium supplementation; divalent cations and regulation of cyclic nucleotides in nervous systems; strontium as the substitute for calcium in the excitation-contraction coupling of crayfish muscle fibers; hemodynamic effects of strontium in the dog; some mechanical characteristics of strontium-mediated contractions in heart muscle; effects of calcium, magnesium, and strontium on drug-receptor interactions; strontium and histamine secretion; and effects of strontium in human dental enamel.

  5. Thermally stable laminating resins

    NASA Technical Reports Server (NTRS)

    Jones, R. J.; Vaughan, R. W.; Burns, E. A.

    1972-01-01

    Improved thermally stable laminating resins were developed based on the addition-type pyrolytic polymerization. Detailed monomer and polymer synthesis and characterization studies identified formulations which facilitate press molding processing and autoclave fabrication of glass and graphite fiber reinforced composites. A specific resin formulation, termed P10P was utilized to prepare a Courtaulds HMS reinforced simulated airfoil demonstration part by an autoclave molding process.

  6. Forensic Stable Isotope Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  7. 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.

  8. Atlas of temporal variations - interdisciplinary scientific work

    NASA Astrophysics Data System (ADS)

    Gamburtsev, A. G.; Oleinik, O. V.

    2003-04-01

    The year 2002 will culminate in the publication of the third volume of the fundamental interdisciplinary work "Atlas of Temporal Variations in Natural, Anthropogenic and Social Processes", which now will comprise three volumes (1994, 1998, 2002). The Atlas has pooled the information on the main peculiarities of processes' behaviour in various natural and humanitarian spheres over the widest temporal and spatial range. The main scientific goal of the work consists in discovering the behaviour pattern of natural, anthropogenic and social processes and the cause and effect links between them. Thus, the Atlas contains extensive comparative generalisation from the vastly different data. For one thing, it is a fundamental work on the law-governed nature of evolution in natural and social spheres; for another, it can be used as a reference book and valuable source of information for research in different directions. The authors seek to treat every piece of information as part of an integrated whole. When analysing the data, we operate on the premise that surrounding nature, society and their elements are open dynamic systems. Systems of this kind exhibit non-linear characteristics and a tendency towards ordered and chaotic behaviour. These features are revealed in the course of the analysis of time series. The data processing procedures applied are unified, all processes being generally expressed in terms of their time series and time-spectral diagrams. The technique is aimed at determination of investigated parameters' rhythms and the analysis of their evolution. This approach enables us to show the dynamics of processes occurring in absolutely dissimilar objects and performs their comparative analysis, with particular emphasis placed on rhythms and trends. As a result successions of illustrations are obtained and formed the basis of the Atlas. The Atlas covers processes that occur in objects belonging to the lithosphere, atmosphere, hydrosphere and social sphere as well

  9. Comprehensive Retrieval of Spatio-temporal Variations in Atmospheric Radionuclides just after the Fukushima Accident by Analyzing Filter-tapes of Operational Air Pollution Monitoring Stations in Eastern Japan

    NASA Astrophysics Data System (ADS)

    Tsuruta, Haruo; Oura, Yasuji; Ebihara, Mitsuru; Ohara, Toshimasa; Moriguchi, Yuichi; Nakajima, Teruyuki

    2016-04-01

    After the Fukushima Daiichi Nuclear Power Station (FD1NPS) accident on March 11, 2011, many datasets have been available of deposition density of radionuclides in soils in eastern Japan. By contrast, no time-series data of atmospheric radionuclides has been measured in the Fukushima prefecture (FP), although very limited data is available in the Tokyo metropolitan area (TMA) located more than 170 km southwest of the FD1NPS. As a result, atmospheric transport models simulating the atmospheric concentrations and surface deposition of radionuclides have large uncertainty, as well as the estimate of release rate of source terms and of internal exposure from inhalation. One year after the accident, we collected the used filter-tapes installed in Suspended Particulate Matter (SPM) monitors with beta-ray attenuation method operated by local governments in the air pollution monitoring network of eastern Japan. The SPM monitoring stations are mostly located in the urban and/or industrial area to measure the hourly mass concentration of SPM less than 10 μm in diameter for health effect due to atmospheric aerosols. By measuring radionuclides in SPM on the filter-tapes, we retrieved hourly atmospheric Cs-134 and Cs-137 concentrations during March 12-23, 2011, when atmospheric, aquatic, and terrestrial environments were seriously suffered in most of eastern Japan. Until now, we measured hourly radiocesium at around 100 SPM sites in the southern Tohoku region (ST) including the FP and in the TMA. By analysing the dataset, about 10 plumes/polluted air masses with Cs-137 concentrations higher than 10 Bq m-3 were found, and some plumes were newly detected in this study. And the spatio-temporal distributions of atmospheric Cs-137 were clearly shown for all the plumes. The east coast area of the FP where the FD1NPS was located in the centre was attacked several times by the plumes, and suffered the highest time-integrated Cs-137 concentration during the period among the ST and TMA

  10. Temporal beam splitter and temporal interference

    SciTech Connect

    Mendonca, J.T.; Martins, A.M.; Guerreiro, A.

    2003-10-01

    The effect of photon beam splitting in a time-varying medium is described by classical and quantum theoretical models. It generalizes the concept of time refraction, introduced recently by the authors as a natural extrapolation of the usual concepts of refraction and reflection into the time domain. Total time reflection is shown to exist. A sequence of time refraction processes is shown to lead to temporal interference effects. The concept of temporal beam splitter is introduced. Bogoliubov transformations for the temporal beam splitter are derived. Resonant amplification of light by change in time in the optical medium is shown to exist.

  11. SILAC-based temporal phosphoproteomics.

    PubMed

    Francavilla, Chiara; Hekmat, Omid; Blagoev, Blagoy; Olsen, Jesper V

    2014-01-01

    In recent years, thanks to advances in Mass Spectrometry (MS)-based quantitative proteomics, studies on signaling pathways have moved from a detailed description of individual components to system-wide analysis of entire signaling cascades, also providing spatio-temporal views of intracellular pathways. Quantitative proteomics that combines stable isotope labeling by amino acid in cell culture (SILAC) with enrichment strategies for post-translational modification-bearing peptides and high-performance tandem mass spectrometry represents a powerful and unbiased approach to monitor dynamic signaling events. Here we provide an optimized SILAC-based proteomic workflow to analyze temporal changes in phosphoproteomes, which involve a generic three step enrichment protocol for phosphopeptides. SILAC-labeled peptides from digested whole cell lysates are as a first step enriched for phosphorylated tyrosines by immunoaffinity and then further enriched for phosphorylated serine/threonine peptides by strong cation exchange in combination with titanium dioxide-beads chromatography. Analysis of enriched peptides on Orbitrap-based MS results in comprehensive and accurate reconstruction of temporal changes of signaling networks.

  12. Temporal bone meningiomas.

    PubMed

    Hooper, R; Siu, K; Cousins, V

    1990-10-01

    Meningiomas should be considered in the differential diagnosis of space-occupying lesions of the temporal bone. Five cases of meningiomas of the temporal bone are described and the literature reviewed. These tumours may stimulate Schwannomas and glomus tumours in their presentation and radiological findings. The tumours were managed by combining standard neurosurgical approaches with temporal bone and skull base techniques.

  13. 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...

  14. 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...

  15. Dynamically Stable Legged Locomotion

    DTIC Science & Technology

    1983-12-13

    in/ 1200 lb-in @2000 psig Theoretical Max. Work per Stroke 83 N-i 740 lb-in ’p.,. ~.55 ,, C C . --- - 29 2.9 Appendix B: Kinematics of 3D Machine We...344 70 Simulation khip (N/m) Frequency Ratio Result r.320.8 1500 4.999 unstable r.323.3 1200 4.523 unstable r.325.1 880 3.954 stable r.313.4 632 3.449...down. VVer is the vertical velocity of the hopper. T are the torques applied on the body at the hip. To achieve path control in the plane, we need to

  16. Stable predictive control horizons

    NASA Astrophysics Data System (ADS)

    Estrada, Raúl; Favela, Antonio; Raimondi, Angelo; Nevado, Antonio; Requena, Ricardo; Beltrán-Carbajal, Francisco

    2012-04-01

    The stability theory of predictive and adaptive predictive control for processes of linear and stable nature is based on the hypothesis of a physically realisable driving desired trajectory (DDT). The formal theoretical verification of this hypothesis is trivial for processes with a stable inverse, but it is not for processes with an unstable inverse. The extended strategy of predictive control was developed with the purpose of overcoming methodologically this stability problem and it has delivered excellent performance and stability in its industrial applications given a suitable choice of the prediction horizon. From a theoretical point of view, the existence of a prediction horizon capable of ensuring stability for processes with an unstable inverse was proven in the literature. However, no analytical solution has been found for the determination of the prediction horizon values which guarantee stability, in spite of the theoretical and practical interest of this matter. This article presents a new method able to determine the set of prediction horizon values which ensure stability under the extended predictive control strategy formulation and a particular performance criterion for the design of the DDT generically used in many industrial applications. The practical application of this method is illustrated by means of simulation examples.

  17. 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.

  18. A new temporal bone and cadaver head holder for temporal bone surgical technique training.

    PubMed

    Feng, Guodong; Lv, Wei; Tian, Xu; Wu, Haiyan; Gao, Zhiqiang

    2013-01-01

    To design a new temporal bone and cadaver head holder, overcoming the drawbacks of the bowl-type holder and other existing holders for dissection, and thereby benefiting training and research on temporal bone surgery. We designed and fabricated a novel holder with a horizontal arm that can be connected with an object holder specific for the temporal bone or a three-pin fixture specific for cadaver heads. A separate hand support helps to stabilize the hand during examinations on the temporal bone and skull base. The use of the temporal bone and cadaver head holder by 30 trainees during our temporal bone surgical technique courses held by the Department of Otolaryngology, Peking Union Medical College Hospital (PUMCH) worked better than other holders and saved laboratory time. It has become the standard equipment of the Temporal Bone Laboratory of PUMCH. The temporal bone and cadaver head holder we describe is compact, stable and easily adjustable. It offers considerable advantages to trainees. © 2013 S. Karger AG, Basel.

  19. Marginally Stable Nuclear Burning

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod E.; Altamirano, D.

    2012-01-01

    Thermonuclear X-ray bursts result from unstable nuclear burning of the material accreted on neutron stars in some low mass X-ray binaries (LMXBs). Theory predicts that close to the boundary of stability oscillatory burning can occur. This marginally stable regime has so far been identified in only a small number of sources. We present Rossi X-ray Timing Explorer (RXTE) observations of the bursting, high- inclination LMXB 4U 1323-619 that reveal for the first time in this source the signature of marginally stable burning. The source was observed during two successive RXTE orbits for approximately 5 ksec beginning at 10:14:01 UTC on March 28, 2011. Significant mHz quasi- periodic oscillations (QPO) at a frequency of 8.1 mHz are detected for approximately 1600 s from the beginning of the observation until the occurrence of a thermonuclear X-ray burst at 10:42:22 UTC. The mHz oscillations are not detected following the X-ray burst. The average fractional rms amplitude of the mHz QPOs is 6.4% (3 - 20 keV), and the amplitude increases to about 8% below 10 keV.This phenomenology is strikingly similar to that seen in the LMXB 4U 1636-53. Indeed, the frequency of the mHz QPOs in 4U 1323-619 prior to the X-ray burst is very similar to the transition frequency between mHz QPO and bursts found in 4U 1636-53 by Altamirano et al. (2008). These results strongly suggest that the observed QPOs in 4U 1323-619 are, like those in 4U 1636-53, due to marginally stable nuclear burning. We also explore the dependence of the energy spectrum on the oscillation phase, and we place the present observations within the context of the spectral evolution of the accretion-powered flux from the source.

  20. Stable local oscillator microcircuit.

    SciTech Connect

    Brocato, Robert Wesley

    2006-10-01

    This report gives a description of the development of a Stable Local Oscillator (StaLO) Microcircuit. The StaLO accepts a 100MHz input signal and produces output signals at 1.2, 3.3, and 3.6 GHz. The circuit is built as a multi-chip module (MCM), since it makes use of integrated circuit technologies in silicon and lithium niobate as well as discrete passive components. The StaLO uses a comb generator followed by surface acoustic wave (SAW) filters. The comb generator creates a set of harmonic components of the 100MHz input signal. The SAW filters are narrow bandpass filters that are used to select the desired component and reject all others. The resulting circuit has very low sideband power levels and low phase noise (both less than -40dBc) that is limited primarily by the phase noise level of the input signal.

  1. Stable cosmic vortons.

    PubMed

    Garaud, Julien; Radu, Eugen; Volkov, Mikhail S

    2013-10-25

    We present solutions in the gauged U(1)×U(1) model of Witten describing vortons-spinning flux loops stabilized against contraction by the centrifugal force. Vortons were heuristically described many years ago; however, the corresponding field theory solutions were not obtained and so the stability issue remained open. We construct explicitly a family of stationary vortons characterized by their charge and angular momentum. Most of them are unstable and break in pieces when perturbed. However, thick vortons with a small radius preserve their form in the 3+1 nonlinear dynamical evolution. This gives the first ever evidence of stable vortons and impacts several branches of physics where they could potentially exist. These range from cosmology, since vortons could perhaps contribute to dark matter, to QCD and condensed matter physics.

  2. Stable umbral chromospheric structures

    NASA Astrophysics Data System (ADS)

    Henriques, V. M. J.; Scullion, E.; Mathioudakis, M.; Kiselman, D.; Gallagher, P. T.; Keenan, F. P.

    2015-02-01

    Aims: We seek to understand the morphology of the chromosphere in sunspot umbra. We investigate if the horizontal structures observed in the spectral core of the Ca II H line are ephemeral visuals caused by the shock dynamics of more stable structures, and examine their relationship with observables in the H-alpha line. Methods: Filtergrams in the core of the Ca II H and H-alpha lines as observed with the Swedish 1-m Solar Telescope are employed. We utilise a technique that creates composite images and tracks the flash propagation horizontally. Results: We find 0.̋15 wide horizontal structures, in all of the three target sunspots, for every flash where the seeing is moderate to good. Discrete dark structures are identified that are stable for at least two umbral flashes, as well as systems of structures that live for up to 24 min. We find cases of extremely extended structures with similar stability, with one such structure showing an extent of 5''. Some of these structures have a correspondence in H-alpha, but we were unable to find a one-to-one correspondence for every occurrence. If the dark streaks are formed at the same heights as umbral flashes, there are systems of structures with strong departures from the vertical for all three analysed sunspots. Conclusions: Long-lived Ca II H filamentary horizontal structures are a common and likely ever-present feature in the umbra of sunspots. If the magnetic field in the chromosphere of the umbra is indeed aligned with the structures, then the present theoretical understanding of the typical umbra needs to be revisited. Movies associated to Figs. 3 and 4 are available in electronic form at http://www.aanda.org

  3. 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.

  4. Economic Impact of Stable Flies

    USDA-ARS?s Scientific Manuscript database

    A dynamic model was created to estimate the economic impact of stable flies on livestock production. Based upon a nationwide average of 10 stable flies per animal for 3 months per year, the model estimates the impact of stable flies to be $543 million to the dairy industry, $1.34 billion to pasture ...

  5. Temperature Compensated Sapphire Resonator for Ultra-Stable Oscillator Capability

    NASA Technical Reports Server (NTRS)

    Dick, G. J.; Santiago, D. G.; Wang, R. T.

    1994-01-01

    We report on the design and test of a whispering gallery sapphire resonator for which the dominant microwave mode family shows frequency-stable, compensated operation for temperatures above 77 kelvin.

  6. Strong, Long-Term Temporal Dynamics of an Ecological Network

    PubMed Central

    Olesen, Jens M.; Stefanescu, Constantí; Traveset, Anna

    2011-01-01

    Nature is organized into complex, dynamical networks of species and their interactions, which may influence diversity and stability. However, network research is, generally, short-term and depict ecological networks as static structures only, devoid of any dynamics. This hampers our understanding of how nature responds to larger disturbances such as changes in climate. In order to remedy this we studied the long-term (12-yrs) dynamics of a flower-visitation network, consisting of flower-visiting butterflies and their nectar plants. Global network properties, i.e. numbers of species and links, as well as connectance, were temporally stable, whereas most species and links showed a strong temporal dynamics. However, species of butterflies and plants varied bimodally in their temporal persistance: Sporadic species, being present only 1–2(-5) years, and stable species, being present (9-)11–12 years, dominated the networks. Temporal persistence and linkage level of species, i.e. number of links to other species, made up two groups of species: Specialists with a highly variable temporal persistence, and temporally stable species with a highly variable linkage level. Turnover of links of specialists was driven by species turnover, whereas turnover of links among generalists took place through rewiring, i.e. by reshuffling existing interactions. However, in spite of this strong internal dynamics of species and links the network appeared overall stable. If this global stability-local instability phenomenon is general, it is a most astonishing feature of ecological networks. PMID:22125597

  7. 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

  8. Experimental temporal quantum steering

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    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.

  9. 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

  10. Stable interface treatment in overset grid methods

    NASA Astrophysics Data System (ADS)

    Sharan, Nek; Pantano, Carlos; Bodony, Daniel

    2014-11-01

    Overset grid methods enable complex geometry capability while retaining high-order finite difference-based discretizations; however, no provably stable methods currently exist that are free of numerical dissipation. We have developed and will present the construction of time-stable interface treatments for solving hyperbolic and parabolic problems on overset grids. The treatments are based on the simultaneous approximation term (SAT) penalty method, and we use summation-by-parts (SBP) operators for the derivative approximations. Error analysis is performed to determine the order of interpolation that retains the accuracy of the spatial finite difference operator. Optimal estimates on the error bound are derived and confirmed with a convergence study of numerical simulations. The conditions for the treatment to be conservative have also been determined. Numerical examples are presented to confirm the stability and accuracy of the methods. This work is supported by NASA's Revolutionary Computational Aerosciences program as part of the Aeronautical Sciences Project.

  11. Detecting spatial and temporal dot patterns in noise

    NASA Astrophysics Data System (ADS)

    Drum, Bruce

    1991-06-01

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

  12. 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.

  13. Temporal Prediction in lieu of Periodic Stimulation

    PubMed Central

    Schroeder, Charles E.; Wyart, Valentin

    2016-01-01

    Predicting not only what will happen, but also when it will happen is extremely helpful for optimizing perception and action. Temporal predictions driven by periodic stimulation increase perceptual sensitivity and reduce response latencies. At the neurophysiological level, a single mechanism has been proposed to mediate this twofold behavioral improvement: the rhythmic entrainment of slow cortical oscillations to the stimulation rate. However, temporal regularities can occur in aperiodic contexts, suggesting that temporal predictions per se may be dissociable from entrainment to periodic sensory streams. We investigated this possibility in two behavioral experiments, asking human participants to detect near-threshold auditory tones embedded in streams whose temporal and spectral properties were manipulated. While our findings confirm that periodic stimulation reduces response latencies, in agreement with the hypothesis of a stimulus-driven entrainment of neural excitability, they further reveal that this motor facilitation can be dissociated from the enhancement of auditory sensitivity. Perceptual sensitivity improvement is unaffected by the nature of temporal regularities (periodic vs aperiodic), but contingent on the co-occurrence of a fulfilled spectral prediction. Altogether, the dissociation between predictability and periodicity demonstrates that distinct mechanisms flexibly and synergistically operate to facilitate perception and action. SIGNIFICANCE STATEMENT Temporal predictions are increasingly recognized as fundamental instruments for optimizing performance, enabling mammals to exploit regularities in the world. However, the notion of temporal predictions is often confounded with the idea of entrainment to periodic sensory inputs. At the behavioral level, it is also unclear whether perceptual sensitivity and reaction time improvements benefit the same way from temporal predictions and periodic stimulation. In two behavioral experiments on human

  14. Approximate Qualitative Temporal Reasoning

    DTIC Science & Technology

    2001-01-01

    A. G. Cohn, B. Bennett, J. Goodday , and N. Gotts. Qualitative spatial representation and reasoning with the region connection calculus. geoinformatica... Goodday and A. G. Cohn. Conceptual neighborhoods in temporal and spatial reasoning. In ECAI-94 Spatial and Temporal Reasoning Workshop, 1994. T

  15. Temporal Bisection in Children.

    ERIC Educational Resources Information Center

    Droit-Volet, Sylvie; Wearden, John H.

    2001-01-01

    Trained 3-, 5-, and 8-year-olds in temporal bisection task, with nonstandard comparison stimuli spaced linearly between short or long standard visual stimuli. Statistical analyses and results from different theoretical models of the data all suggested that temporal sensitivity was higher in the 8-year-olds than in younger groups, even when the…

  16. Stable electroosmotically driven actuators

    NASA Astrophysics Data System (ADS)

    Sritharan, Deepa; Motsebo, Mylene; Tumbic, Julia; Smela, Elisabeth

    2013-04-01

    We have previously presented "nastic" actuators based on electroosmotic (EO) pumping of fluid in microchannels using high electric fields for potential application in soft robotics. In this work we address two challenges facing this technology: applying EO to meso-scale devices and the stability of the pumping fluid. The hydraulic pressure achieved by EO increases with as 1/d2, where d is the depth of the microchannel, but the flow rate (which determines the stroke and the speed) is proportional to nd, where n is the number of channels. Therefore to get high force and high stroke the device requires a large number of narrow channels, which is not readily achievable using standard microfabrication techniques. Furthermore, for soft robotics the structure must be soft. In this work we present a method of fabricating a three-dimensional porous elastomer to serve as the array of channels based on a sacrificial sugar scaffold. We demonstrate the concept by fabricating small pumps. The flexible devices were made from polydimethylsiloxane (PDMS) and comprise the 3D porous elastomer flanked on either side by reservoirs containing electrodes. The second issue addressed here involves the pumping fluid. Typically, water is used for EO, but water undergoes electrolysis even at low voltages. Since EO takes place at kV, these systems must be open to release the gases. We have recently reported that propylene carbonate (PC) is pumped at a comparable rate as water and is also stable for over 30 min at 8 kV. Here we show that PC is, however, degraded by moisture, so future EO systems must prevent water from reaching the PC.

  17. Delayed reinforcement of operant behavior.

    PubMed

    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 responses and reinforcers can be isolated from other features of the environment that often accompany delays, such as stimuli or changes in the temporal distribution or rate of reinforcement. The second question is that of the effects of delays on operant behavior. Beyond the common denominator of a temporal separation between reinforcers and the responses that produce them, delay of reinforcement procedures differ from one another along several dimensions, making delay effects circumstance dependent. The final question is one of interpreting delay of reinforcement effects. It centers on the role of the response-reinforcer temporal relation in the context of other, concurrently operating behavioral processes.

  18. DELAYED REINFORCEMENT OF OPERANT BEHAVIOR

    PubMed Central

    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 responses and reinforcers can be isolated from other features of the environment that often accompany delays, such as stimuli or changes in the temporal distribution or rate of reinforcement. The second question is that of the effects of delays on operant behavior. Beyond the common denominator of a temporal separation between reinforcers and the responses that produce them, delay of reinforcement procedures differ from one another along several dimensions, making delay effects circumstance dependent. The final question is one of interpreting delay of reinforcement effects. It centers on the role of the response–reinforcer temporal relation in the context of other, concurrently operating behavioral processes. PMID:20676272

  19. 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.

  20. 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

  1. Spatio-temporal clustering

    NASA Astrophysics Data System (ADS)

    Kisilevich, Slava; Mansmann, Florian; Nanni, Mirco; Rinzivillo, Salvatore

    Spatio-temporal clustering is a process of grouping objects based on their spatial and temporal similarity. It is relatively new subfield of data mining which gained high popularity especially in geographic information sciences due to the pervasiveness of all kinds of location-based or environmental devices that record position, time or/and environmental properties of an object or set of objects in real-time. As a consequence, different types and large amounts of spatio-temporal data became available that introduce new challenges to data analysis and require novel approaches to knowledge discovery. In this chapter we concentrate on the spatio-temporal clustering in geographic space. First, we provide a classification of different types of spatio-temporal data. Then, we focus on one type of spatio-temporal clustering - trajectory clustering, provide an overview of the state-of-the-art approaches and methods of spatio-temporal clustering and finally present several scenarios in different application domains such as movement, cellular networks and environmental studies.

  2. Temporal ghost imaging

    NASA Astrophysics Data System (ADS)

    Kuusela, Tom A.

    2017-05-01

    Ghost imaging in the spatial domain is nowadays a well-known but still a surprising phenomenon. It was demonstrated originally with entangled photon pairs and later with pseudo-thermal light. Very recently it was shown that it is also possible to create ghost images in the time domain using temporally incoherent light. In this case the object is not a spatial mask but a temporally varying modulation of the light. We show a simple experimental setup for temporal ghost imaging that can be implemented even in the undergraduate physics laboratory. Results are very close to the those reported in the first experimental study of this phenomenon.

  3. Temporal Dynamic Controllability Revisited

    NASA Technical Reports Server (NTRS)

    Morris, Paul H.; Muscettola, Nicola

    2005-01-01

    An important issue for temporal planners is the ability to handle temporal uncertainty. We revisit the question of how to determine whether a given set of temporal requirements are feasible in the light of uncertain durations of some processes. In particular, we consider how best to determine whether a network is Dynamically Controllable, i.e., whether a dynamic strategy exists for executing the network that is guaranteed to satisfy the requirements. Previous work has shown the existence of a pseudo-polynomial algorithm for testing Dynamic Controllability. Here, we greatly simplify the previous framework, and present a true polynomial algorithm with a cutoff based only on the number of nodes.

  4. Object temporal connotation.

    PubMed

    Becchio, Cristina; Bertone, Cesare

    2003-07-01

    Recent studies show that what connotes an object is first of all a certain spatio-temporal structure. In this paper we describe some of the temporal features characterizing the temporal structure of objects: pre-existence, persistence, conservation of identity in spite of perceptive discontinuity, surviving changes in colour, size, and shape. We argue that time is an indispensable attribute for every type of object and briefly discuss the implication of this view with respect to a specific neuropsychological syndrome: unilateral spatial neglect.

  5. [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.

  6. 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…

  7. 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.

  8. Multilayered temporal modeling for the clinical domain.

    PubMed

    Lin, Chen; Dligach, Dmitriy; Miller, Timothy A; Bethard, Steven; Savova, Guergana K

    2016-03-01

    To develop an open-source temporal relation discovery system for the clinical domain. The system is capable of automatically inferring temporal relations between events and time expressions using a multilayered modeling strategy. It can operate at different levels of granularity--from rough temporality expressed as event relations to the document creation time (DCT) to temporal containment to fine-grained classic Allen-style relations. We evaluated our systems on 2 clinical corpora. One is a subset of the Temporal Histories of Your Medical Events (THYME) corpus, which was used in SemEval 2015 Task 6: Clinical TempEval. The other is the 2012 Informatics for Integrating Biology and the Bedside (i2b2) challenge corpus. We designed multiple supervised machine learning models to compute the DCT relation and within-sentence temporal relations. For the i2b2 data, we also developed models and rule-based methods to recognize cross-sentence temporal relations. We used the official evaluation scripts of both challenges to make our results comparable with results of other participating systems. In addition, we conducted a feature ablation study to find out the contribution of various features to the system's performance. Our system achieved state-of-the-art performance on the Clinical TempEval corpus and was on par with the best systems on the i2b2 2012 corpus. Particularly, on the Clinical TempEval corpus, our system established a new F1 score benchmark, statistically significant as compared to the baseline and the best participating system. Presented here is the first open-source clinical temporal relation discovery system. It was built using a multilayered temporal modeling strategy and achieved top performance in 2 major shared tasks. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Multilayered temporal modeling for the clinical domain

    PubMed Central

    Dligach, Dmitriy; Miller, Timothy A; Bethard, Steven; Savova, Guergana K

    2016-01-01

    Objective To develop an open-source temporal relation discovery system for the clinical domain. The system is capable of automatically inferring temporal relations between events and time expressions using a multilayered modeling strategy. It can operate at different levels of granularity—from rough temporality expressed as event relations to the document creation time (DCT) to temporal containment to fine-grained classic Allen-style relations. Materials and Methods We evaluated our systems on 2 clinical corpora. One is a subset of the Temporal Histories of Your Medical Events (THYME) corpus, which was used in SemEval 2015 Task 6: Clinical TempEval. The other is the 2012 Informatics for Integrating Biology and the Bedside (i2b2) challenge corpus. We designed multiple supervised machine learning models to compute the DCT relation and within-sentence temporal relations. For the i2b2 data, we also developed models and rule-based methods to recognize cross-sentence temporal relations. We used the official evaluation scripts of both challenges to make our results comparable with results of other participating systems. In addition, we conducted a feature ablation study to find out the contribution of various features to the system’s performance. Results Our system achieved state-of-the-art performance on the Clinical TempEval corpus and was on par with the best systems on the i2b2 2012 corpus. Particularly, on the Clinical TempEval corpus, our system established a new F1 score benchmark, statistically significant as compared to the baseline and the best participating system. Conclusion Presented here is the first open-source clinical temporal relation discovery system. It was built using a multilayered temporal modeling strategy and achieved top performance in 2 major shared tasks. PMID:26521301

  10. 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

  11. 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.

  12. Compact and stable multibeam fiber injector

    SciTech Connect

    Collins, L. F., LLNL

    1998-07-01

    A compact and stable 20-beam injector was built for launching laser light into fibers for Fabry Perot velocity measurements of shock-driven surfaces. The fiber injector uses commercial mounts on mini-rails. Dielectric-coated beamsplitters provide accurate amplitude division. Minimal adjustments for stable operation are permitted by the use of a real-time video-viewer. The video system includes a non-linear camera for CW alignment and a linearized camera with a frame grabber for pulsed measurement and analysis. All 20-injection points are displayed on a single monitor. Optical requirements are given for image relay and magnification. Stimulated Brillouin scattering limitations on high-power are quantified.

  13. Stable isotopes in leaf water of terrestrial plants.

    PubMed

    Cernusak, Lucas A; Barbour, Margaret M; Arndt, Stefan K; Cheesman, Alexander W; English, Nathan B; Feild, Taylor S; Helliker, Brent R; Holloway-Phillips, Meisha M; Holtum, Joseph A M; Kahmen, Ansgar; McInerney, Francesca A; Munksgaard, Niels C; Simonin, Kevin A; Song, Xin; Stuart-Williams, Hilary; West, Jason B; Farquhar, Graham D

    2016-05-01

    Leaf water contains naturally occurring stable isotopes of oxygen and hydrogen in abundances that vary spatially and temporally. When sufficiently understood, these can be harnessed for a wide range of applications. Here, we review the current state of knowledge of stable isotope enrichment of leaf water, and its relevance for isotopic signals incorporated into plant organic matter and atmospheric gases. Models describing evaporative enrichment of leaf water have become increasingly complex over time, reflecting enhanced spatial and temporal resolution. We recommend that practitioners choose a model with a level of complexity suited to their application, and provide guidance. At the same time, there exists some lingering uncertainty about the biophysical processes relevant to patterns of isotopic enrichment in leaf water. An important goal for future research is to link observed variations in isotopic composition to specific anatomical and physiological features of leaves that reflect differences in hydraulic design. New measurement techniques are developing rapidly, enabling determinations of both transpired and leaf water δ(18) O and δ(2) H to be made more easily and at higher temporal resolution than previously possible. We expect these technological advances to spur new developments in our understanding of patterns of stable isotope fractionation in leaf water. © 2016 JohnWiley & Sons Ltd.

  14. [Stable fibrous subaortic stenosis].

    PubMed

    Attié, F; Dumont, C; Mispireta, J; Kuri, J; Mata, L A

    1975-01-01

    The authors studied 37 patients belonging to the Pediatric Cardiology Service of the Institute National of Cardiology who were carriers of fixed fibrinous subaortic stenosis. The diagnosis was established by surgery or autopsy. Isolated subvalvular obstruction was found in 24 patients (63%), which represents the most important number of cases in the literature. The analysis of the 24 cases permitted important conclusions: 1. All the patients had systolic thrills in the suprasternal hollow and carotidinous pathways. 2. No case had protosystolic click. In all, the murmur's epicenter was in the 3rd and 4th IIS in the parasternal line, a fact which can lead to a mistaken diagnosis of interventricular septal defect. 66.6% of the patients had a diastolic murmur heard in the aortic focus, a secondary accompaniement to secondary valvular aortic insufficiency. The intensity of the second aortic sound held an inverse relationship to the magnitude of the gradient. The presence of paradoxic splitting of the second heart sound as well as prolongation of the expulsion period in the carotidogram are indexes for the severity of the obstruction. 3. A relationship between the severity of the lesion and the dilatation of the left atrium was found. The cardiomegaly had no relationship to the severity of the obstruction with the increase in ventricular telediastolic pressure or to the evolution time. 4. An adequate hemodynamic study permits evaluating and locating the site of the obstruction. Likewise, precise ventriculography appraises the nature of the narrowing. 5. Aortic regurgitation is located at the valvular level. Aortography permits its affirmation. Probably the stream coming from subvalvular stenosis produces fibrosis or asynchronism in the closing of the aortic valves. 6. Surgical treatment offers excelent perspectives in mortality as well as reducing the gradient. None of our patients operated on had hospital or later death. 7. Postoperatory evaluation was performed on six

  15. Relative Priming of Temporal Local-Global Levels in Auditory Hierarchical Stimuli

    PubMed Central

    List, Alexandra; Justus, Timothy

    2009-01-01

    Priming is a useful tool for ascertaining the circumstances under which previous experiences influence behavior. Previously, using hierarchical stimuli, we demonstrated that selectively attending to one temporal scale of an auditory stimulus improved subsequent attention to a repeated (vs. changed) temporal scale, i.e., we demonstrated inter-trial auditory temporal level-priming. Here, we have extended those results to address whether level-priming relied on absolute or relative temporal information. Both relative and absolute temporal information are important in auditory perception: speech and music can be recognized over various temporal scales, but become uninterpretable to a listener when presented too quickly or slowly. We first confirmed that temporal level-priming generalized over new temporal scales. Second, in the context of multiple temporal scales, we found that temporal level-priming operates predominantly on the basis of relative, rather than absolute, temporal information. These findings are discussed in the context of expectancies and relational invariance in audition. PMID:20045889

  16. A temporal cloak at telecommunication data rate.

    PubMed

    Lukens, Joseph M; Leaird, Daniel E; Weiner, Andrew M

    2013-06-13

    Through advances in metamaterials--artificially engineered media with exotic properties, including negative refractive index--the once fanciful invisibility cloak has now assumed a prominent place in scientific research. By extending these concepts to the temporal domain, investigators have recently described a cloak which hides events in time by creating a temporal gap in a probe beam that is subsequently closed up; any interaction which takes place during this hole in time is not detected. However, these results are limited to isolated events that fill a tiny portion of the temporal period, giving a fractional cloaking window of only about 10(-4) per cent at a repetition rate of 41 kilohertz (ref. 15)--which is much too low for applications such as optical communications. Here we demonstrate another technique for temporal cloaking, which operates at telecommunication data rates and, by exploiting temporal self-imaging through the Talbot effect, hides optical data from a receiver. We succeed in cloaking 46 per cent of the entire time axis and conceal pseudorandom digital data at a rate of 12.7 gigabits per second. This potential to cloak real-world messages introduces temporal cloaking into the sphere of practical application, with immediate ramifications in secure communications.

  17. Stable isotopes in obesity research.

    PubMed

    Dolnikowski, Gregory G; Marsh, Julian B; Das, Sai Krupa; Welty, Francine K

    2005-01-01

    Obesity is recognized as a major public health problem. Obesity is a multifactorial disease and is often associated with a wide range of comorbidities including hypertension, non-insulin dependent (Type II) diabetes mellitus, and cardiovascular disease, all of which contribute to morbidity and mortality. This review deals with stable isotope mass spectrometric methods and the application of stable isotopes to metabolic studies of obesity. Body composition and total energy expenditure (TEE) can be measured by mass spectrometry using stable isotope labeled water, and the metabolism of protein, lipid, and carbohydrate can be measured using appropriate labeled tracer molecules.

  18. Stable Spheromaks with Profile Control

    SciTech Connect

    Fowler, T K; Jayakumar, R

    2008-01-29

    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.

  19. Temporal Decentering and the Development of Temporal Concepts

    ERIC Educational Resources Information Center

    McCormack, Teresa; Hoerl, Christoph

    2008-01-01

    This article reviews some recent research on the development of temporal cognition, with reference to Weist's (1989) account of the development of temporal understanding. Weist's distinction between two levels of temporal decentering is discussed, and empirical studies that may be interpreted as measuring temporal decentering are described. We…

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

    SciTech Connect

    Bornholdt, S.; Graudenz, D.

    1993-07-01

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

  1. Stable and sporadic symbiotic communities of coral and algal holobionts

    PubMed Central

    Hester, Eric R; Barott, Katie L; Nulton, Jim; Vermeij, Mark JA; Rohwer, Forest L

    2016-01-01

    Coral and algal holobionts are assemblages of macroorganisms and microorganisms, including viruses, Bacteria, Archaea, protists and fungi. Despite a decade of research, it remains unclear whether these associations are spatial–temporally stable or species-specific. We hypothesized that conflicting interpretations of the data arise from high noise associated with sporadic microbial symbionts overwhelming signatures of stable holobiont members. To test this hypothesis, the bacterial communities associated with three coral species (Acropora rosaria, Acropora hyacinthus and Porites lutea) and two algal guilds (crustose coralline algae and turf algae) from 131 samples were analyzed using a novel statistical approach termed the Abundance-Ubiquity (AU) test. The AU test determines whether a given bacterial species would be present given additional sampling effort (that is, stable) versus those species that are sporadically associated with a sample. Using the AU test, we show that coral and algal holobionts have a high-diversity group of stable symbionts. Stable symbionts are not exclusive to one species of coral or algae. No single bacterial species was ubiquitously associated with one host, showing that there is not strict heredity of the microbiome. In addition to the stable symbionts, there was a low-diversity community of sporadic symbionts whose abundance varied widely across individual holobionts of the same species. Identification of these two symbiont communities supports the holobiont model and calls into question the hologenome theory of evolution. PMID:26555246

  2. Functional rigidity of a methane biofilter during the temporal microbial succession.

    PubMed

    Kim, Tae Gwan; Jeong, So-Yeon; Cho, Kyung-Suk

    2014-04-01

    Temporal microbial succession was investigated in relation to the performance of a methane biofilter. A laboratory-scale biofilter packed with perlite was operated for 108 days, without a deliberate biomass control. The system performance was stable over the period with a mean elimination capacity of 1,563 g m(-3) day(-1), despite a temporal deterioration (45-56 days). Ribosomal-tag pyrosequencing showed that bacterial communities at days 14-28 were distinct from those of days 68-108. The accumulation of nonviable substances strongly coincided with the community change (R (2) > 0.97). Rhodobacter, Hydrogenophaga, and Methylomonas were dominated in the earlier period, while Methylocaldum and Methylococcus were abundant in the later period. The methanotrophic proportion gradually increased to 41 %, and type I methanotrophs became predominant over time. However, community structure and methanotrophic population density stably retained over time, allowing the system to keep the similar performance. Therefore, the perlite biofilter system was functionally rigid against the temporal microbial succession.

  3. Modified Leclerc blocking procedure with miniplates and temporal fascial flap for recurrent temporomandibular joint dislocation.

    PubMed

    Ying, Binbin; Hu, Jing; Zhu, Songsong

    2013-05-01

    This study introduced the modified Leclerc blocking procedure with miniplate and temporal fascial flap for recurrent temporomandibular joint (TMJ) dislocation and evaluated its clinical effects. Seven patients were treated by the modified Leclerc blocking procedure with miniplate and temporal fascial flap. The postoperative follow-up period ranged from half a year to 2 years to access the maximal mouth opening, TMJ disorder symptoms (pain and sound), and incidence of recurrence. No recurrence was observed in all of the 7 patients postoperatively. The mean preoperative and postoperative MMOs were 49.7 mm and 40.1 mm, respectively. There were 3 patients who reported the alleviation of pain and/or sound postoperatively. Two older patients with long-term course of disease reported no improvement of the TMJ symptoms in terms of pain and sound postoperatively. Our results showed that the modified Leclerc blocking procedure with miniplates and temporal fascial flap provided a more stable support for the condylar movement with less recurrence, suggesting that this operation could be a good alternative for the treatment of recurrent TMJ dislocation.

  4. 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

  5. Stable Lobed Mixer With Combustion Demonstrated and Measured

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA Lewis Research Center collaborated with the Massachusetts Institute of Technology (MIT) on an experiment to study the use of lobed mixers to improve the fuel-air mixing process and increase combustion intensity in combustors with minimal pressure loss. This experiment is the first known stable combusting flow studied for this device, and the data show a much faster and much more uniform combustion process than for flat-plate mixers. Several potential benefits may be realized from this study in future combustors, including a reduction in NO_x emissions because of the more uniform temperature distribution. The experiment was done in Lewis' Planar Reacting Shear Layer facility, which was adapted to accept a lobed mixer in addition to the original planar tip. A graduate student at MIT provided the mixer design concept, and Lewis provided the engineering, operations, and research expertise. The experiment used hydrogen-nitrogen mixtures to react with vitiated hot air at 920 K. A flow speed of about 120 m/sec and a speed ratio of 0.5 were used. Flow diagnostics consisted of traversing fine-wire thermocouples and pitot probes for flow mapping. Supplementary fluorescence images were taken with a charged coupled device (CCD) camera to show the location and temporal behavior of the reaction zone. The data showed that the lobed mixer consumed the reactants between 3 to 10 times faster than a corresponding planar shear layer. The figure shows the dramatic difference in the measured temperature distribution with and without the lobed mixer. The increased mixing rate was due to a larger interfacial area as well as to the secondary flow from the streamwise vortices off the tips of the lobes. In addition, the fluorescence images showed that the lobes acted as flame stabilizers.

  6. Spatial and temporal variations of microbial community in a mixed plug-flow loop reactor fed with dairy manure

    PubMed Central

    Li, Yueh-Fen; Chen, Po-Hsu; Yu, Zhongtang

    2014-01-01

    Mixed plug-flow loop reactor (MPFLR) has been widely adopted by the US dairy farms to convert cattle manure to biogas. However, the microbiome in MPFLR digesters remains unexplored. In this study, the microbiome in a MPFLR digester operated on a mega-dairy farm was examined thrice over a 2 month period. Within 23 days of retention time, 55–70% of total manure solid was digested. Except for a few minor volatile fatty acids (VFAs), total VFA concentration and pH remained similar along the course of the digester and over time. Metagenomic analysis showed that although with some temporal variations, the bacterial community was rather stable spatially in the digester. The methanogenic community was also stable both spatially and temporally in the digester. Among methanogens, genus Methanosaeta dominated in the digester. Quantitative polymerase chain reaction (qPCR) analysis and metagenomic analysis yielded different relative abundance of individual genera of methanogens, especially for Methanobacterium, which was predominant based on qPCR analysis but undetectable by metagenomics. Collectively, the results showed that only small microbial and chemical gradients existed within the digester, and the digestion process occurred similarly throughout the MPFLR digester. The findings of this study may help improve the operation and design of this type of manure digesters. PMID:24690147

  7. Spatial and temporal variations of microbial community in a mixed plug-flow loop reactor fed with dairy manure.

    PubMed

    Li, Yueh-Fen; Chen, Po-Hsu; Yu, Zhongtang

    2014-07-01

    Mixed plug-flow loop reactor (MPFLR) has been widely adopted by the US dairy farms to convert cattle manure to biogas. However, the microbiome in MPFLR digesters remains unexplored. In this study, the microbiome in a MPFLR digester operated on a mega-dairy farm was examined thrice over a 2 month period. Within 23 days of retention time, 55-70% of total manure solid was digested. Except for a few minor volatile fatty acids (VFAs), total VFA concentration and pH remained similar along the course of the digester and over time. Metagenomic analysis showed that although with some temporal variations, the bacterial community was rather stable spatially in the digester. The methanogenic community was also stable both spatially and temporally in the digester. Among methanogens, genus Methanosaeta dominated in the digester. Quantitative polymerase chain reaction (qPCR) analysis and metagenomic analysis yielded different relative abundance of individual genera of methanogens, especially for Methanobacterium, which was predominant based on qPCR analysis but undetectable by metagenomics. Collectively, the results showed that only small microbial and chemical gradients existed within the digester, and the digestion process occurred similarly throughout the MPFLR digester. The findings of this study may help improve the operation and design of this type of manure digesters.

  8. Earthquakes in stable continental crust

    SciTech Connect

    Johnson, A.C.; Kanter, L.R. )

    1990-03-01

    Earthquakes can strike even in stable crust, well away from the familiar earthquake zones at the edges of tectonic plates, but their mere occurrence is both a source of concern in planning critical facilities such as nuclear power plants. The authors sought answers to two major questions: Just how much seismic activity does take place within the stable parts of continents And are there specific geologic features that make some areas of stable crust particularly susceptible to earthquakes They began by studying North America alone, but it soon became clear that the fairly short record of these rare events on a single continent would not provide enough data for reliable analysis. Hence, they decided to substitute space for time--to survey earthquake frequency and distribution in stable continental areas worldwide. This paper discusses their findings.

  9. Earthquakes in Stable Continental Crust.

    ERIC Educational Resources Information Center

    Johnston, Arch C.; Kanter, Lisa R.

    1990-01-01

    Discussed are some of the reasons for earthquakes which occur in stable crust away from familiar zones at the ends of tectonic plates. Crust stability and the reactivation of old faults are described using examples from India and Australia. (CW)

  10. Earthquakes in Stable Continental Crust.

    ERIC Educational Resources Information Center

    Johnston, Arch C.; Kanter, Lisa R.

    1990-01-01

    Discussed are some of the reasons for earthquakes which occur in stable crust away from familiar zones at the ends of tectonic plates. Crust stability and the reactivation of old faults are described using examples from India and Australia. (CW)

  11. Functionally stable and phylogenetically diverse microbial enrichments from microbial fuel cells during wastewater treatment.

    PubMed

    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/m(2), the maximum power density was 13 mW/m(2), 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

  12. 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

  13. Stable isotope research pool inventory

    SciTech Connect

    Not Available

    1988-02-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56.

  14. 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

  15. Multi-stable perception balances stability and sensitivity

    PubMed Central

    Pastukhov, Alexander; García-Rodríguez, Pedro E.; Haenicke, Joachim; Guillamon, Antoni; Deco, Gustavo; Braun, Jochen

    2013-01-01

    We report that multi-stable perception operates in a consistent, dynamical regime, balancing the conflicting goals of stability and sensitivity. When a multi-stable visual display is viewed continuously, its phenomenal appearance reverses spontaneously at irregular intervals. We characterized the perceptual dynamics of individual observers in terms of four statistical measures: the distribution of dominance times (mean and variance) and the novel, subtle dependence on prior history (correlation and time-constant). The dynamics of multi-stable perception is known to reflect several stabilizing and destabilizing factors. Phenomenologically, its main aspects are captured by a simplistic computational model with competition, adaptation, and noise. We identified small parameter volumes (~3% of the possible volume) in which the model reproduced both dominance distribution and history-dependence of each observer. For 21 of 24 data sets, the identified volumes clustered tightly (~15% of the possible volume), revealing a consistent “operating regime” of multi-stable perception. The “operating regime” turned out to be marginally stable or, equivalently, near the brink of an oscillatory instability. The chance probability of the observed clustering was <0.02. To understand the functional significance of this empirical “operating regime,” we compared it to the theoretical “sweet spot” of the model. We computed this “sweet spot” as the intersection of the parameter volumes in which the model produced stable perceptual outcomes and in which it was sensitive to input modulations. Remarkably, the empirical “operating regime” proved to be largely coextensive with the theoretical “sweet spot.” This demonstrated that perceptual dynamics was not merely consistent but also functionally optimized (in that it balances stability with sensitivity). Our results imply that multi-stable perception is not a laboratory curiosity, but reflects a functional

  16. Memory Retrieval as Temporal Discrimination

    ERIC Educational Resources Information Center

    Brown, Gordon D. A.; Vousden, Janet I.; McCormack, Teresa

    2009-01-01

    Temporal distinctiveness models of memory retrieval claim that memories are organised partly in terms of their positions along a temporal dimension, and suggest that memory retrieval involves temporal discrimination. According to such models the retrievability of memories should be related to the discriminability of their temporal distances at the…

  17. Temporal Lorentzian spectral triples

    NASA Astrophysics Data System (ADS)

    Franco, Nicolas

    2014-09-01

    We present the notion of temporal Lorentzian spectral triple which is an extension of the notion of pseudo-Riemannian spectral triple with a way to ensure that the signature of the metric is Lorentzian. A temporal Lorentzian spectral triple corresponds to a specific 3 + 1 decomposition of a possibly noncommutative Lorentzian space. This structure introduces a notion of global time in noncommutative geometry. As an example, we construct a temporal Lorentzian spectral triple over a Moyal-Minkowski spacetime. We show that, when time is commutative, the algebra can be extended to unbounded elements. Using such an extension, it is possible to define a Lorentzian distance formula between pure states with a well-defined noncommutative formulation.

  18. Temporal molecular and isotopic analysis of active bacterial communities in two New Zealand sponges.

    PubMed

    Simister, Rachel; Taylor, Michael W; Rogers, Karyne M; Schupp, Peter J; Deines, Peter

    2013-07-01

    The characterization of changes in microbial communities is an essential step towards a better understanding of host-microbe associations. It is well established that sponges (phylum Porifera) harbour a diverse and abundant microbial community, but it is not known whether these microbial communities change over time. Here, we followed two sponge species (Ancorina alata and Tethya stolonifera) over a 2-year sampling period using RNA (16S rRNA)-based amplicon pyrosequencing and bulk stable isotope analysis (δ(13) C and δ(15)N). A total of 4468 unique operational taxonomic units (OTUs) was identified, which were affiliated with 26 bacterial phyla. Bacterial communities of both sponge species were remarkably stable throughout the monitoring period, driven by a small number of OTUs that dominated their respective communities. Variability of sponge-associated bacterial communities was driven by OTUs that were low in abundance or transient over time. Stable isotope analysis provided evidence of both bacteria- and host-derived nutrients and their variability throughout the season. While δ(15) N values were similar, significant differences were found in δ(13) C of sponge tissue, indicative of a varying reliance on particulate organic matter as a carbon source. Further temporal studies, such as those undertaken here, will be highly valuable to identify which members of a sponge bacterial community are truly symbiotic in nature.

  19. Rapid auditory learning of temporal gap detection.

    PubMed

    Mishra, Srikanta K; Panda, Manasa R

    2016-07-01

    The rapid initial phase of training-induced improvement has been shown to reflect a genuine sensory change in perception. Several features of early and rapid learning, such as generalization and stability, remain to be characterized. The present study demonstrated that learning effects from brief training on a temporal gap detection task using spectrally similar narrowband noise markers defining the gap (within-channel task), transfer across ears, however, not across spectrally dissimilar markers (between-channel task). The learning effects associated with brief training on a gap detection task were found to be stable for at least a day. These initial findings have significant implications for characterizing early and rapid learning effects.

  20. Temporal limits on rubber hand illusion reflect individuals' temporal resolution in multisensory perception.

    PubMed

    Costantini, Marcello; Robinson, Jeffrey; Migliorati, Daniele; Donno, Brunella; Ferri, Francesca; Northoff, Georg

    2016-12-01

    Synchronous, but not asynchronous, multisensory stimulation has been successfully employed to manipulate the experience of body ownership, as in the case of the rubber hand illusion. Hence, it has been assumed that the rubber hand illusion is bound by the same temporal rules as in multisensory integration. However, empirical evidence of a direct link between the temporal limits on the rubber hand illusion and those on multisensory integration is still lacking. Here we provide the first comprehensive evidence that individual susceptibility to the rubber hand illusion depends upon the individual temporal resolution in multisensory perception, as indexed by the temporal binding window. In particular, in two studies we showed that the degree of temporal asynchrony necessary to prevent the induction of the rubber hand illusion depends upon the individuals' sensitivity to perceiving asynchrony during visuo-tactile stimulation. That is, the larger the temporal binding window, as inferred from a simultaneity judgment task, the higher the level of asynchrony tolerated in the rubber hand illusion. Our results suggest that current neurocognitive models of body ownership can be enriched with a temporal dimension. Moreover, our results suggest that the different aspects of body ownership operate over different time scales.

  1. Basin-scale spatio-temporal variability and control of phytoplankton photosynthesis in the Baltic Sea: The first multiwavelength fast repetition rate fluorescence study operated on a ship-of-opportunity

    NASA Astrophysics Data System (ADS)

    Houliez, Emilie; Simis, Stefan; Nenonen, Susanna; Ylöstalo, Pasi; Seppälä, Jukka

    2017-05-01

    This study presents the results of the first field application of a flow-through multi-wavelength Fast Repetition Rate fluorometer (FRRF) equipped with two excitation channels (458 and 593 nm). This device aims to improve the measurement of mixed cyanobacteria and algae community's photosynthetic parameters and was designed to be easily incorporated into existing ferrybox systems. We present a spatiotemporal analysis of the maximum photochemical efficiency (Fv/Fm) and functional absorption cross section (σPSII) recorded from April to August 2014 on a ship-of-opportunity commuting twice per week between Helsinki (Finland) and Travemünde (Germany). Temporal variations of Fv/Fm and σPSII differed between areas of the Baltic Sea. However, even though the Baltic Sea is characterized by several physico-chemical gradients, no gradient was observed in Fv/Fm and σPSII spatial distribution suggesting complex interactions between biotic and abiotic controls. σPSII was sensitive to phytoplankton seasonal succession and thus differed according to the wavelength used to excite photosystems II (PSII) pigments. This was particularly true in summer when high σPSII(593) values were observed later and longer than high σPSII(458) values, reflecting the role of cyanobacteria in photosynthetic light uptake measured at community scale. In contrast, Fv/Fm variations were similar after excitation at 458 nm or 593 nm suggesting that the adjustment of Fv/Fm in response to environmental factors was similar for the different groups (algae vs. cyanobacteria) present within the phytoplankton community.

  2. Takayasu and temporal arteritis.

    PubMed

    Schmidt, Wolfgang A

    2006-01-01

    Takayasu and temporal arteritis are primary large-vessel vasculitides. Ultrasound directly depicts the inflamed vessel wall, which is homogenously and circumferentially thickened. Furthermore, stenoses and occlusions occur. Ultrasound almost completely depicts the whole length of the common superficial temporal arteries, including the frontal and parietal ramus. Inflammation is often segmental. This may lead to a false-negative histology. The wall swelling is hypoechoic in acute temporal arteritis. It disappears within 2-3 weeks with corticosteroid treatment. Sonographers should use 8-15 MHz linear probes. The pulse repetition frequency should be about 2.5 kHz. Color box steering and beam steering should be maximal. It is essential that the color covers the artery lumen exactly. Sensitivities and specificities with regard to clinical diagnosis and histology are high. Large-vessel giant cell arteritis is a subset of temporal arteritis, with involvement of the subclavian, axillary, and proximal brachial arteries. The wall swelling resolves much slower with treatment. In Takayasu arteritis ultrasound is a valuable diagnostic tool to investigate particularly the common carotid, subclavian, and vertebral arteries. The echogenicity of the arterial wall thickening is, in general, higher than in giant cell arteritis, as the nature of Takayasu arteritis is more chronic, with less wall edema.

  3. Temporal Aperture Modulation

    NASA Technical Reports Server (NTRS)

    Proctor, R. J.

    1981-01-01

    The two types of modulation techniques useful to X-ray imaging are reviewed. The use of optimum coded temporal aperature modulation is shown, in certain cases, to offer an advantage over a spatial aperture modulator. Example applications of a diffuse anisotropic X-ray background experiment and a wide field of view hard X-ray imager are discussed.

  4. Information and Temporality

    NASA Astrophysics Data System (ADS)

    Flender, Christian

    2016-09-01

    Being able to give reasons for what the world is and how it works is one of the defining characteristics of modernity. Mathematical reason and empirical observation brought science and engineering to unprecedented success. However, modernity has reached a post-state where an instrumental view of technology needs revision with reasonable arguments and evidence, i.e. without falling back to superstition and mysticism. Instrumentally, technology bears the potential to ease and to harm. Easing and harming can't be controlled like the initial development of technology is a controlled exercise for a specific, mostly easing purpose. Therefore, a revised understanding of information technology is proposed based upon mathematical concepts and intuitions as developed in quantum mechanics. Quantum mechanics offers unequaled opportunities because it raises foundational questions in a precise form. Beyond instrumentalism it enables to raise the question of essences as that what remains through time what it is. The essence of information technology is acausality. The time of acausality is temporality. Temporality is not a concept or a category. It is not epistemological. As an existential and thus more comprehensive and fundamental than a concept or a category temporality is ontological; it does not simply have ontic properties. Rather it exhibits general essences. Datability, significance, spannedness and openness are general essences of equiprimordial time (temporality).

  5. Temporal control of i-motif switch lifetimes for autonomous operation of transient DNA nanostructures† †Electronic supplementary information (ESI) available: Detailed experimental procedures, materials and methods, a list of all oligonucleotide sequences and supporting figures. See DOI: 10.1039/c7sc00646b Click here for additional data file.

    PubMed Central

    Heinen, L.

    2017-01-01

    Functional DNA nanotechnology creates increasingly complex behaviors useful for sensing, actuation or computation, as enabled via the integration of dynamic and responsive structural DNA motifs. However, temporally controlled and dynamic DNA structures with programmable lifetimes, that are able to operate autonomously and self-revert to the starting state are challenging to achieve due to tedious and very system-specific sequence design. Here, we present a straightforward concept to program transient lifetimes into DNA duplexes based on the pH-sensitive DNA i-motif switch. We integrate the i-motif switch with an internal, non-linear pH-resetting function using a rationally designed chemical reaction framework, by which the switch autonomously undergoes a complete “off–on–off”-cycle without the use of additional external triggers. The lifetime of the activated “on”-state (i.e. the hybridized state) can be systematically programmed over several hours. The system can be readily implemented into hybrid DNA structures on larger length scales. Focusing on autonomous materials, we demonstrate temporal control of transient fluorescence signals and temporary aggregation of gold nanoparticles. PMID:28580123

  6. Weather dependent estimation of continent-wide wind power generation based on spatio-temporal clustering

    NASA Astrophysics Data System (ADS)

    Schyska, Bruno U.; Couto, António; von Bremen, Lueder; Estanqueiro, Ana; Heinemann, Detlev

    2017-05-01

    Europe is facing the challenge of increasing shares of energy from variable renewable sources. Furthermore, it is heading towards a fully integrated electricity market, i.e. a Europe-wide electricity system. The stable operation of this large-scale renewable power system requires detailed information on the amount of electricity being transmitted now and in the future. To estimate the actual amount of electricity, upscaling algorithms are applied. Those algorithms - until now - however, only exist for smaller regions (e.g. transmission zones and single wind farms). The aim of this study is to introduce a new approach to estimate Europe-wide wind power generation based on spatio-temporal clustering. We furthermore show that training the upscaling model for different prevailing weather situations allows to further reduce the number of reference sites without losing accuracy.

  7. Stable Degeneracies for Ising Models

    NASA Astrophysics Data System (ADS)

    Knauf, Andreas

    2016-10-01

    We introduce and consider the notion of stable degeneracies of translation invariant energy functions, taken at spin configurations of a finite Ising model. By this term we mean the lack of injectivity that cannot be lifted by changing the interaction. We show that besides the symmetry-induced degeneracies, related to spin flip, translation and reflection, there exist additional stable degeneracies, due to more subtle symmetries. One such symmetry is the one of the Singer group of a finite projective plane. Others are described by combinatorial relations akin to trace identities. Our results resemble traits of the length spectrum for closed geodesics on a Riemannian surface of constant negative curvature. There, stable degeneracy is defined w.r.t. Teichmüller space as parameter space.

  8. Interferometric methods for spatio temporal seismic monitoring in underground mines

    NASA Astrophysics Data System (ADS)

    Dales, Philippe; Audet, Pascal; Olivier, Gerrit; Mercier, Jean-Philippe

    2017-08-01

    In active underground mining environments, monitoring of the rockmass has important implications for both safety and productivity. Monitoring can be accomplished by exploiting the many passive seismic sources (microearthquakes, drilling, ore-crushers etc.) around the mine on the condition they can be accurately detected and located. We implement a popular beamforming-like approach that uses cross-correlation functions in a maximum likelihood search to locate sources of seismic energy. We illustrate the technique with a synthetic example in which two simultaneous sources are located and discuss briefly the effects of different processing parameters. We demonstrate the effectiveness of this technique by monitoring both impulsive sources (microearthquakes) and other persistent sources (drilling and ore-crushers) in two active underground mines. We then propose how this information can be used in conjunction with ambient seismic noise interferometry to estimate seismic Green's functions under temporally variable and anisotropic wavefield conditions. Alternatively, we demonstrate how stable persistent sources, typically seen as contaminants in ambient noise applications, can be used to monitor changing rockmass conditions and potentially guide mining operations.

  9. Discovery of fuzzy temporal association rules.

    PubMed

    Lee, Wan-Jui; Lee, Shie-Jue

    2004-12-01

    We propose a data mining system for discovering interesting temporal patterns from large databases. The mined patterns are expressed in fuzzy temporal association rules which satisfy the temporal requirements specified by the user. Temporal requirements specified by human beings tend to be ill-defined or uncertain. To deal with this kind of uncertainty, a fuzzy calendar algebra is developed to allow users to describe desired temporal requirements in fuzzy calendars easily and naturally. Fuzzy operations are provided and users can define complicated fuzzy calendars to discover the knowledge in the time intervals that are of interest to them. A border-based mining algorithm is proposed to find association rules incrementally. By keeping useful information of the database in a border, candidate itemsets can be computed in an efficient way. Updating of the discovered knowledge due to addition and deletion of transactions can also be done efficiently. The kept information can be used to help save the work of counting and unnecessary scans over the updated database can be avoided. Simulation results show the effectiveness of the proposed system. A performance comparison with other systems is also given.

  10. Multisensory temporal integration: Task and stimulus dependencies

    PubMed Central

    Stevenson, Ryan A.; Wallace, Mark T.

    2013-01-01

    The ability of human sensory systems to integrate information across the different modalities provides a wide range of behavioral and perceptual benefits. This integration process is dependent upon the temporal relationship of the different sensory signals, with stimuli occurring close together in time typically resulting in the largest behavior changes. The range of temporal intervals over which such benefits are seen is typically referred to as the temporal binding window (TBW). Given the importance of temporal factors in multisensory integration under both normal and atypical circumstances such as autism and dyslexia, the TBW has been measured with a variety of experimental protocols that differ according to criterion, task, and stimulus type, making comparisons across experiments difficult. In the current study we attempt to elucidate the role that these various factors play in the measurement of this important construct. The results show a strong effect of stimulus type, with the TBW assessed with speech stimuli being both larger and more symmetrical than that seen using simple and complex non-speech stimuli. These effects are robust across task and statistical criteria, and are highly consistent within individuals, suggesting substantial overlap in the neural and cognitive operations that govern multisensory temporal processes. PMID:23604624

  11. Multisensory temporal integration: task and stimulus dependencies.

    PubMed

    Stevenson, Ryan A; Wallace, Mark T

    2013-06-01

    The ability of human sensory systems to integrate information across the different modalities provides a wide range of behavioral and perceptual benefits. This integration process is dependent upon the temporal relationship of the different sensory signals, with stimuli occurring close together in time typically resulting in the largest behavior changes. The range of temporal intervals over which such benefits are seen is typically referred to as the temporal binding window (TBW). Given the importance of temporal factors in multisensory integration under both normal and atypical circumstances such as autism and dyslexia, the TBW has been measured with a variety of experimental protocols that differ according to criterion, task, and stimulus type, making comparisons across experiments difficult. In the current study, we attempt to elucidate the role that these various factors play in the measurement of this important construct. The results show a strong effect of stimulus type, with the TBW assessed with speech stimuli being both larger and more symmetrical than that seen using simple and complex non-speech stimuli. These effects are robust across task and statistical criteria and are highly consistent within individuals, suggesting substantial overlap in the neural and cognitive operations that govern multisensory temporal processes.

  12. Operation PLUMBBOB. Operational Summary

    DTIC Science & Technology

    1979-10-01

    General 65 9.2 Organization 65 9.3 Observer Categories 65 9.3.1 Official Observers 65 9.3.2 Employee Observers 65 9.3.3 FCDA Observers...Operational, Training and Troop Observer participation in Operation PILGRIM. d. Coordinate FCDA participation in the Military Effects Test Program. 7...Test Group (CETG), Federal Civil Defense Administration ( FCDA ), structures projects. Also, the DOD dome and arch Project 3.6 and related FCDA dome

  13. Metal Stable Isotopes in Paleoceanography

    NASA Astrophysics Data System (ADS)

    Anbar, Ariel D.; Rouxel, Olivier

    2007-05-01

    Considered esoteric only a few years ago, research into the stable isotope geochemistry of transition metals is moving into the geoscience mainstream. Although initial attention focused on the potential use of some of these nontraditional isotope systems as biosignatures, they are now emerging as powerful paleoceanographic proxies. In particular, the Fe and Mo isotope systems are providing information about changes in oxygenation and metal cycling in ancient oceans. Zn, Cu, Tl, and a number of other metals and metalloids also show promise. Here we review the basis of stable isotope fractionation as it applies to these elements, analytical considerations, and the current status and future prospects of this rapidly developing research area.

  14. Stable isotopic studies on chitin

    SciTech Connect

    Schimmelmann, A.

    1985-01-01

    Carbon, nitrogen, oxygen, and hydrogen stable isotope ratios of the poly-amino-sugar chitin isolated from exo-skeletons of 75 arthropod species collected in 59 locations were determined. The objectives were to understand the environmental, climatic, and biological influences on the isotope ratios and to develop a data base for interpreting isotope ratios of archaeological and fossil chitins. Measurements of stable isotope ratios in chitin isolates showed large variations which reflect intrinsic compositional and isotopic heterogeneities as well as differences caused by methods of preparation.

  15. 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.

  16. 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.

  17. 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.

  18. Optimal Temporal Risk Assessment

    PubMed Central

    Balci, Fuat; Freestone, David; Simen, Patrick; deSouza, Laura; Cohen, Jonathan D.; Holmes, Philip

    2011-01-01

    Time is an essential feature of most decisions, because the reward earned from decisions frequently depends on the temporal statistics of the environment (e.g., on whether decisions must be made under deadlines). Accordingly, evolution appears to have favored a mechanism that predicts intervals in the seconds to minutes range with high accuracy on average, but significant variability from trial to trial. Importantly, the subjective sense of time that results is sufficiently imprecise that maximizing rewards in decision-making can require substantial behavioral adjustments (e.g., accumulating less evidence for a decision in order to beat a deadline). Reward maximization in many daily decisions therefore requires optimal temporal risk assessment. Here, we review the temporal decision-making literature, conduct secondary analyses of relevant published datasets, and analyze the results of a new experiment. The paper is organized in three parts. In the first part, we review literature and analyze existing data suggesting that animals take account of their inherent behavioral variability (their “endogenous timing uncertainty”) in temporal decision-making. In the second part, we review literature that quantitatively demonstrates nearly optimal temporal risk assessment with sub-second and supra-second intervals using perceptual tasks (with humans and mice) and motor timing tasks (with humans). We supplement this section with original research that tested human and rat performance on a task that requires finding the optimal balance between two time-dependent quantities for reward maximization. This optimal balance in turn depends on the level of timing uncertainty. Corroborating the reviewed literature, humans and rats exhibited nearly optimal temporal risk assessment in this task. In the third section, we discuss the role of timing uncertainty in reward maximization in two-choice perceptual decision-making tasks and review literature that implicates timing uncertainty

  19. Morphological study of surgical approach by superior temporal sulcus-temporal horn of lateral ventricle approach using volume rendering.

    PubMed

    Sun, Wei; Jia, Linpei; Dong, Yidian; Zhao, Hang; Liu, Haoyuan; Yang, Kerong; Li, Youqiong

    2014-03-01

    In this research, we acquired the length of the superior temporal sulcus, the shortest distance from the superior temporal sulcus to the temporal horn of the lateral ventricle, and the approach angle between the median sagittal plane and the shortest segment from the superior temporal sulcus to the temporal horn of the lateral ventricle measuring 98 specimens by magnetic resonance imaging volume rendering. At the same time, we preliminarily oriented the point of the superior temporal sulcus, which is closest to the temporal horn of the lateral ventricle, aimed at finding out the best entrance point of surgical approach through the superior temporal sulcus to the temporal horn of the lateral ventricle and reducing the damage to optic radiation as well as other nerve fibers during the operation. The results indicate that the point at the front side 3/5 of the superior temporal sulcus may be the ideal surgical approach entrance point, and there is no difference between 2 cerebral hemispheres (P < 0.05).

  20. Modeling the Temporal Evolution of Postoperative Complications

    PubMed Central

    Feld, Shara I.; Cobian, Alexander G.; Tevis, Sarah E.; Kennedy, Gregory D.; Craven, Mark W.

    2016-01-01

    Post-operative complications have a significant impact on patient morbidity and mortality; these impacts are exacerbated when patients experience multiple complications. However, the task of modeling the temporal sequencing of complications has not been previously addressed. We present an approach based on Markov chain models for characterizing the temporal evolution of post-operative complications represented in the American College of Surgeons National Surgery Quality Improvement Program database. Our work demonstrates that the models have significant predictive value. In particular, an inhomogenous Markov chain model effectively predicts the development of serious complications (coma longer than a day, cardiac arrest, myocardial infarction, septic shock, renal failure, pneumonia) and interventional complications (unplanned re-intubation, longer than 2 days on a ventilator and bleeding transfusion). PMID:28269851

  1. 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

  2. Synthesis of thermally stable polymers

    NASA Technical Reports Server (NTRS)

    Butler, G. B.

    1978-01-01

    The reaction of bis triazo linediones with divinyl esters and substituted styrenes was investigated. Twenty new polymers were derived via reaction of two previously synthesized bis triazol linediones and four new bis atriazol linediones with eight styrenes. The structure and polymer properties of these thermally stable polymers was examined. The reaction of triazo linediones with enol esters was also considered.

  3. Bayesian stable isotope mixing models

    EPA Science Inventory

    In this paper we review recent advances in Stable Isotope Mixing Models (SIMMs) and place them into an over-arching Bayesian statistical framework which allows for several useful extensions. SIMMs are used to quantify the proportional contributions of various sources to a mixtur...

  4. Bayesian stable isotope mixing models

    EPA Science Inventory

    In this paper we review recent advances in Stable Isotope Mixing Models (SIMMs) and place them into an over-arching Bayesian statistical framework which allows for several useful extensions. SIMMs are used to quantify the proportional contributions of various sources to a mixtur...

  5. Temporal Lobe Epilepsy Semiology

    PubMed Central

    Blair, Robert D. G.

    2012-01-01

    Epilepsy represents a multifaceted group of disorders divided into two broad categories, partial and generalized, based on the seizure onset zone. The identification of the neuroanatomic site of seizure onset depends on delineation of seizure semiology by a careful history together with video-EEG, and a variety of neuroimaging technologies such as MRI, fMRI, FDG-PET, MEG, or invasive intracranial EEG recording. Temporal lobe epilepsy (TLE) is the commonest form of focal epilepsy and represents almost 2/3 of cases of intractable epilepsy managed surgically. A history of febrile seizures (especially complex febrile seizures) is common in TLE and is frequently associated with mesial temporal sclerosis (the commonest form of TLE). Seizure auras occur in many TLE patients and often exhibit features that are relatively specific for TLE but few are of lateralizing value. Automatisms, however, often have lateralizing significance. Careful study of seizure semiology remains invaluable in addressing the search for the seizure onset zone. PMID:22957241

  6. Temporal lobe epilepsy semiology.

    PubMed

    Blair, Robert D G

    2012-01-01

    Epilepsy represents a multifaceted group of disorders divided into two broad categories, partial and generalized, based on the seizure onset zone. The identification of the neuroanatomic site of seizure onset depends on delineation of seizure semiology by a careful history together with video-EEG, and a variety of neuroimaging technologies such as MRI, fMRI, FDG-PET, MEG, or invasive intracranial EEG recording. Temporal lobe epilepsy (TLE) is the commonest form of focal epilepsy and represents almost 2/3 of cases of intractable epilepsy managed surgically. A history of febrile seizures (especially complex febrile seizures) is common in TLE and is frequently associated with mesial temporal sclerosis (the commonest form of TLE). Seizure auras occur in many TLE patients and often exhibit features that are relatively specific for TLE but few are of lateralizing value. Automatisms, however, often have lateralizing significance. Careful study of seizure semiology remains invaluable in addressing the search for the seizure onset zone.

  7. 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.

  8. Temporal Data, Temporal Data Models, Temporal Data Languages and Temporal Database Systems

    DTIC Science & Technology

    1988-06-01

    bibliographies are in chronological order dating from the 1960’s. Breutmann, B., Falkenberg , E., Mauer, R ., CSL: A language for Defining Conceptual Schemas... Falkenberg , E., and Mauer, R ., CSL: A language for Defining Conceptual Schemas, Data Base Architect, North-Holland Publishing Company, 1979. 33. Jones, S...of real-time military applications using temporal database computers. DTIC INS ECTED N~ ~AA DTIC TAF Li Av ....... C~C. -: , r I I %A TABLE OF

  9. Comprehensive Retrieval of Spatio-temporal Variations in Atmospheric Radionuclides just after the Fukushima Accident by Analyzing Filter-tapes of Operational Air Pollution Monitoring Stations in Eastern Japan

    NASA Astrophysics Data System (ADS)

    Tsuruta, H.; Oura, Y.; Ebihara, M.; Ohara, T.; Nakajima, T.

    2015-12-01

    After the Fukushima Daiichi Nuclear Power Station (FD1NPS) accident on March 11, 2011, many datasets have been available of deposition density of radionuclides in soils in eastern Japan. By contrast, no time-series data of atmospheric radionuclides has been measured in the Fukushima prefecture (FP), although very limited data is available in the Tokyo metropolitan area (TMA) located more than 170 km southwest of the FD1NPS. As a result, atmospheric transport models simulating the atmospheric concentrations and surface deposition of radionuclides have large uncertainty, as well as the estimate of release rate of source terms and of internal exposure from inhalation. One year after the accident, we collected the used filter-tapes installed in Suspended Particulate Matter (SPM) monitors with beta-ray attenuation method operated by local governments in the air pollution monitoring network of eastern Japan. By measuring radionuclides in SPM on the filter-tapes, we retrieved hourly atmospheric Cs-134 and Cs-137 concentrations during March 12-23, 2011, when atmospheric, aquatic, and terrestrial environments were seriously suffered in most of eastern Japan. Until now, we measured hourly radiocesium at around 100 SPM sites in the southern Tohoku region (ST) including the FP and in the TMA. By analysing the dataset, nine major plumes with Cs-137 concentrations higher than 10 Bq m-3 were found, and some plumes were newly found in this study. A local area of relatively high Cs-137 deposition density in the TMA by precipitation on the morning of March 21, was consistent with an area where the time-integrated atmospheric Cs-137 concentrations were also high due to the transport of a plume on the morning of March 21. In the FP, however, the correlation was not so clear. High radionuclides trapped in a cloud layer might be transported to the ST with relatively high Cs-137 deposition densities, because the atmospheric Cs-137 concentrations were under the detection limit.

  10. 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.

  11. Imaging of the temporal bone.

    PubMed

    Abele, Travis A; Wiggins, Richard H

    2015-01-01

    A variety of congenital, infectious, inflammatory, vascular, and benign and malignant neoplastic pathology affects the temporal bone. Knowledge of normal temporal bone anatomy and space-specific differential diagnoses is key to imaging interpretation of temporal bone. Correlation with clinical history and physical examination is vital to making the correct diagnosis or providing an appropriate differential. Computed tomography and magnetic resonance imaging are complementary imaging modalities in the evaluation of temporal bone abnormalities.

  12. Pre-semantically defined temporal windows for cognitive processing

    PubMed Central

    Pöppel, Ernst

    2009-01-01

    Neuronal oscillations of different frequencies are hypothesized to be basic for temporal perception; this theoretical concept provides the frame to discuss two temporal mechanisms that are thought to be essential for cognitive processing. One such mechanism operates with periods of oscillations in the range of some tens of milliseconds, and is used for complexity reduction of temporally and spatially distributed neuronal activities. Experimental evidence comes from studies on temporal-order threshold, choice reaction time, single-cell activities, evoked responses in neuronal populations or latency distributions of oculomotor responses. The other mechanism refers to pre-semantic integration in the temporal range of approximately 2–3 s. Experimental evidence comes from studies on temporal reproduction, sensorimotor synchronization, intentional movements, speech segmentation, the shift rate of ambiguous stimuli in the visual or auditory modality or the temporal modulation of the mismatch negativity. These different observations indicate the existence of a universal process of temporal integration underlying the mental machinery. This process is believed to be basic for maintenance and change of perceptual identity. Owing to the omnipresence of this kind of temporal segmentation, it is suggested to use this process for a pragmatic definition of the states of being conscious or the ‘subjective presence’. PMID:19487191

  13. Temporal Large-Eddy Simulation

    NASA Technical Reports Server (NTRS)

    Pruett, C. D.; Thomas, B. C.

    2004-01-01

    In 1999, Stolz and Adams unveiled a subgrid-scale model for LES based upon approximately inverting (defiltering) the spatial grid-filter operator and termed .the approximate deconvolution model (ADM). Subsequently, the utility and accuracy of the ADM were demonstrated in a posteriori analyses of flows as diverse as incompressible plane-channel flow and supersonic compression-ramp flow. In a prelude to the current paper, a parameterized temporal ADM (TADM) was developed and demonstrated in both a priori and a posteriori analyses for forced, viscous Burger's flow. The development of a time-filtered variant of the ADM was motivated-primarily by the desire for a unifying theoretical and computational context to encompass direct numerical simulation (DNS), large-eddy simulation (LES), and Reynolds averaged Navier-Stokes simulation (RANS). The resultant methodology was termed temporal LES (TLES). To permit exploration of the parameter space, however, previous analyses of the TADM were restricted to Burger's flow, and it has remained to demonstrate the TADM and TLES methodology for three-dimensional flow. For several reasons, plane-channel flow presents an ideal test case for the TADM. Among these reasons, channel flow is anisotropic, yet it lends itself to highly efficient and accurate spectral numerical methods. Moreover, channel-flow has been investigated extensively by DNS, and a highly accurate data base of Moser et.al. exists. In the present paper, we develop a fully anisotropic TADM model and demonstrate its utility in simulating incompressible plane-channel flow at nominal values of Re(sub tau) = 180 and Re(sub tau) = 590 by the TLES method. The TADM model is shown to perform nearly as well as the ADM at equivalent resolution, thereby establishing TLES as a viable alternative to LES. Moreover, as the current model is suboptimal is some respects, there is considerable room to improve TLES.

  14. Influence of a tone's tonal function on temporal change detection.

    PubMed

    Lebrun-Guillaud, Géraldine; Tillmann, Barbara

    2007-11-01

    Music cognition research has provided evidence that the tonal function of a musical event influences perception and memory. Our study investigated whether tonal function influences a basic temporal judgment, notably the detection of a temporal change disrupting a sequence's regularity. The sequences consisted of six musical events presented in isochrony (or with the fifth event occurring earlier or later): Three chords (instilling a tonal context) were followed by a tone (repeated three times). The tones fulfilled one of two tonal functions in the tonal context. Participants had to detect whether the sequence contained a temporal change and were not informed about tonal manipulations. Discrimination performance (as measured by d') showed an influence of tonal function on temporal change detection: Performance was better for the tonic tone (having the most important tonal function in the key) than for the unstable leading tone, the less stable mediant tone, and even than the stable dominant tone. The outcome shows the influence of listeners' tonal knowledge on a perceptual time judgment and suggests that processing of tonal and temporal structures interact at some stage of processing.

  15. Stable Summability and Approximation Theory

    DTIC Science & Technology

    1989-07-25

    Sturm - Liouville system [2,8] * heat equation [2,11] * Schrodinger and Dirac operators [8,10] * Fourier integrals [3,11], and * abstract operators ...34. Proceedings of the Workshop on Spectral Theory of Sturm - Liouville Differential Operators , Argonne National Laboratory. ANL-84, 73, Dec. 1984, pp. 181-185. 3...AO reports. These are: 1. With H. Diamond, 1. Kon. "A Regularization of the Pointwise Summation of Singular Sturm - Liouville Eigenfunction Expansions

  16. Seasonality and predictability shape temporal species diversity.

    PubMed

    Tonkin, Jonathan D; Bogan, Michael T; Bonada, Núria; Rios-Touma, Blanca; Lytle, David A

    2017-05-01

    Temporal environmental fluctuations, such as seasonality, exert strong controls on biodiversity. While the effects of seasonality are well known, the predictability of fluctuations across years may influence seasonality in ways that are less well understood. The ability of a habitat to support unique, non-nested assemblages of species at different times of the year should depend on both seasonality (occurrence of events at specific periods of the year) and predictability (the reliability of event recurrence) of characteristic ecological conditions. Drawing on tools from wavelet analysis and information theory, we developed a framework for quantifying both seasonality and predictability of habitats, and applied this using global long-term rainfall data. Our analysis predicted that temporal beta diversity should be maximized in highly predictable and highly seasonal climates, and that low degrees of seasonality, predictability, or both would lower diversity in characteristic ways. Using stream invertebrate communities as a case study, we demonstrated that temporal species diversity, as exhibited by community turnover, was determined by a balance between temporal environmental variability (seasonality) and the reliability of this variability (predictability). Communities in highly seasonal mediterranean environments exhibited strong oscillations in community structure, with turnover from one unique community type to another across seasons, whereas communities in aseasonal New Zealand environments fluctuated randomly. Understanding the influence of seasonal and other temporal scales of environmental oscillations on diversity is not complete without a clear understanding of their predictability, and our framework provides tools for examining these trends at a variety of temporal scales, seasonal and beyond. Given the uncertainty of future climates, seasonality and predictability are critical considerations for both basic science and management of ecosystems (e.g., dam

  17. Phase stable RF transport system

    DOEpatents

    Curtin, Michael T.; Natter, Eckard F.; Denney, Peter M.

    1992-01-01

    An RF transport system delivers a phase-stable RF signal to a load, such as an RF cavity of a charged particle accelerator. A circuit generates a calibration signal at an odd multiple frequency of the RF signal where the calibration signal is superimposed with the RF signal on a common cable that connects the RF signal with the load. Signal isolating diplexers are located at both the RF signal source end and load end of the common cable to enable the calibration to be inserted and extracted from the cable signals without any affect on the RF signal. Any phase shift in the calibration signal during traverse of the common cable is then functionally related to the phase shift in the RF signal. The calibration phase shift is used to control a phase shifter for the RF signal to maintain a stable RF signal at the load.

  18. Hierarchy of stable Morse decompositions.

    PubMed

    Szymczak, Andrzej

    2013-05-01

    We introduce an algorithm for construction of the Morse hierarchy, i.e., a hierarchy of Morse decompositions of a piecewise constant vector field on a surface driven by stability of the Morse sets with respect to perturbation of the vector field. Our approach builds upon earlier work on stable Morse decompositions, which can be used to obtain Morse sets of user-prescribed stability. More stable Morse decompositions are coarser, i.e., they consist of larger Morse sets. In this work, we develop an algorithm for tracking the growth of Morse sets and topological events (mergers) that they undergo as their stability is gradually increased. The resulting Morse hierarchy can be explored interactively. We provide examples demonstrating that it can provide a useful coarse overview of the vector field topology.

  19. Stable prenucleation calcium carbonate clusters.

    PubMed

    Gebauer, Denis; Völkel, Antje; Cölfen, Helmut

    2008-12-19

    Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters. We demonstrate that dissolved calcium carbonate in fact contains stable prenucleation ion clusters forming even in undersaturated solution. The cluster formation can be characterized by means of equilibrium thermodynamics, applying a multiple-binding model, which allows for structural preformation. Stable clusters are the relevant species in calcium carbonate nucleation. Such mechanisms may also be important for the crystallization of other minerals.

  20. Stable isotope research pool inventory

    SciTech Connect

    Not Available

    1985-02-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for non-destructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, /sup 40/Ca and /sup 56/Fe. All request for the loan of samples should be submitted with a summary of the purpose of the loan to: Isotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval.

  1. 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...

  2. 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...

  3. Advanced Thermally Stable Jet Fuels

    SciTech Connect

    A. Boehman; C. Song; H. H. Schobert; M. M. Coleman; P. G. Hatcher; S. Eser

    1998-01-01

    The Penn State program in advanced thermally stable jet fuels has five components: 1) development of mechanisms of degradation and solids formation; 2) quantitative measurement of growth of sub-micrometer and micrometer-sized particles during thermal stressing; 3) characterization of carbonaceous deposits by various instrumental and microscopic methods; 4) elucidation of the role of additives in retarding the formation of carbonaceous solids; and 5) assessment of the potential of producing high yields of cycloalkanes and hydroaromatics from coal.

  4. Shelf-Stable Food Safety

    MedlinePlus

    ... Administrative Forms Standard Forms Skip Navigation Z7_0Q0619C0JGR010IFST1G5B10H1 Web Content Viewer (JSR 286) Actions ${title} Loading... / Topics / ... Food Safety / Shelf-Stable Food Safety Z7_0Q0619C0JGR010IFST1G5B10H3 Web Content Viewer (JSR 286) Actions ${title} Loading... Z7_ ...

  5. Stable Stratification for Solar Ponds

    NASA Technical Reports Server (NTRS)

    Mehta, G. D.

    1982-01-01

    Stable density gradient forms in pond saturated with disodium phosphate (DSP). Volume of DSP saturated water tends to develop temperature and density layers. Since tests indicate thermal and density gradients remain in equilibrium at heat removal rates of 60 percent or more of heat input rate, pond containing DSP would be suitable for collecting solar energy and transferring it to heat exchanger for practical use.

  6. 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.

  7. Stable isotopes in tree rings

    NASA Astrophysics Data System (ADS)

    McCarroll, Danny; Loader, Neil J.

    2004-04-01

    Stable isotopes in tree rings could provide palaeoclimate reconstructions with perfect annual resolution and statistically defined confidence limits. Recent advances make the approach viable for non-specialist laboratories. The relevant literature is, however, spread across several disciplines, with common problems approached in different ways. Here we provide the first overview of isotope dendroclimatology, explaining the underlying theory and describing the steps taken in building and interpreting isotope chronologies. Stable carbon isotopes record the balance between stomatal conductance and photosynthetic rate, dominated at dry sites by relative humidity and soil water status and at moist sites by summer irradiance and temperature. Stable oxygen and hydrogen isotopic ratios record source water, which contains a temperature signal, and leaf transpiration, controlled dominantly by vapour pressure deficit. Variable exchange with xylem (source) water during wood synthesis determines the relative strength of the source water and leaf enrichment signals. Producing long Holocene chronologies will require a change in emphasis towards processing very large numbers of samples efficiently, whilst retaining analytical precision. A variety of sample preparation and data treatment protocols have been used, some of which have a deleterious effect on the palaeoclimate signal. These are reviewed and suggestions made for a more standardised approach.

  8. Ultra-stable oscillator with complementary transistors

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L. (Inventor)

    1974-01-01

    A high frequency oscillator, having both good short and long term stability, is formed by including a piezoelectric crystal in the base circuit of a first bi-polar transistor circuit, the bi-polar transistor itself operated below its transitional frequency and having its emitter load chosen so that the input impedance, looking into the base thereof, exhibits a negative resistance in parallel with a capacitive reactance. Combined with this basic circuit is an auxiliary, complementary, second bi-polar transistor circuit of the same form with the piezoelectric crystal being common to both circuits. By this configuration small changes in quiescent current are substantially cancelled by opposite variations in the second bi-polar transistor circuit, thereby achieving from the oscillator a signal having its frequency of oscillation stable over long time periods as well as short time periods.

  9. 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.

  10. 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.

  11. LP based approach to optimal stable matchings

    SciTech Connect

    Teo, Chung-Piaw; Sethuraman, J.

    1997-06-01

    We study the classical stable marriage and stable roommates problems using a polyhedral approach. We propose a new LP formulation for the stable roommates problem. This formulation is non-empty if and only if the underlying roommates problem has a stable matching. Furthermore, for certain special weight functions on the edges, we construct a 2-approximation algorithm for the optimal stable roommates problem. Our technique uses a crucial geometry of the fractional solutions in this formulation. For the stable marriage problem, we show that a related geometry allows us to express any fractional solution in the stable marriage polytope as convex combination of stable marriage solutions. This leads to a genuinely simple proof of the integrality of the stable marriage polytope. Based on these ideas, we devise a heuristic to solve the optimal stable roommates problem. The heuristic combines the power of rounding and cutting-plane methods. We present some computational results based on preliminary implementations of this heuristic.

  12. Spatio-temporal variability in ventricular fibrillation

    NASA Astrophysics Data System (ADS)

    Hastings, Harold M.; Evans, Steven J.; Fenton, Flavio H.; Garfinkel, Alan

    2001-03-01

    It is widely believed that reentrant ventricular tachycardia arises when a spiral wave of activation takes over and drives the ventricle at a rate significantly faster than sinus rhythm, and that ventricular fibrillation (VF), a spatio-temporally disorganized form of cardiac activity leading to sudden cardiac death, arises when this spiral breaks down into multiple offspring. Many authors have found that VF displays significant spatial and temporal organization. The purpose of this research is to quantify time scales and temporal and spatial variability in VF. Surface electrograms were obtained from a stable canine model of VF (cf. Nwasokwa and Bodenheimer, Am. J. Physiol. 253, H643 (1987)). These electrograms were analyzed to identify activation times to an accuracy of 1 ms (cf. Garfinkel et al., J. Clin. Invest. 99, 305 (1997)), yielded eighteen usable series, each containing over 1024 intervactivation intervals, two or three from widely spaced sites per episode of VF, 7 total episodes in 4 animals. Spatial and long-term (60 - 120 sec) temporal variability were analyzed and compared by ANOVA techniques (Evans et al., Proc. Royal Soc. B265, 2167 (1998)). In 6 of 7 episodes, spatial variability among sites was statistically more significant than variability between the first and second halves of each series. More recently, Fourier analysis of these series found three distinct scaling regions, with power law dynamics in each and break points of ca. 1 sec and 4 sec. Finally, there was significant variability in the fraction of "short" interactivation intervals (lasting < 60 of 125 ms) among sites. Together these results suggest variability in physiological properties among sites and consequent variability in spiral wave dynamics among sites.

  13. Temporal resolution in children.

    PubMed

    Wightman, F; Allen, P; Dolan, T; Kistler, D; Jamieson, D

    1989-06-01

    The auditory temporal resolving power of young children was measured using an adaptive forced-choice psychophysical paradigm that was disguised as a video game. 20 children between 3 and 7 years of age and 5 adults were asked to detect the presence of a temporal gap in a burst of half-octave-band noise at band center frequencies of 400 and 2,000 Hz. The minimum detectable gap (gap threshold) was estimated adaptively in 20-trial runs. The mean gap thresholds in the 400-Hz condition were higher for the younger children than for the adults, with the 3-year-old children producing the highest thresholds. Gap thresholds in the 2,000-Hz condition were generally lower than in the 400-Hz condition and showed a similar age effect. All the individual adaptive runs were "adult-like," suggesting that the children were generally attentive to the task during each run. However, the variability of threshold estimates from run to run was substantial, especially in the 3-5-year-old children. Computer simulations suggested that this large within-subjects variability could have resulted from frequent, momentary lapses of attention, which would lead to "guessing" on a substantial portion of the trials.

  14. 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.

  15. 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.

  16. 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...

  17. Verbal memory decline is less frequent at 10 years than at 2 years after temporal lobe surgery for epilepsy.

    PubMed

    Andersson-Roswall, Lena; Malmgren, Kristina; Engman, Elisabeth; Samuelsson, Hans

    2012-08-01

    We investigated individual short- and long-term verbal memory changes after temporal lobe resection for epilepsy. Fifty-one patients (23 operated on the speech-dominant temporal lobe, DTL and 28 on the non-dominant temporal lobe, NDTL) were tested on learning/immediate recall and delayed recall of word-list and word-pairs preoperatively, 2 years postoperatively and 10years postoperatively. Changes were defined using reliable change indices of 23 healthy controls assessed at corresponding intervals. Fewer patients had reliable declines at 10 years than at 2 years (DTL: 13-35% vs 35-44%; NDTL: 0-4% vs 7-21%). Four DTL patients (17%) had reliable declines in ≥2 tests at 10-year follow-up. More NDTL patients had improvement at 10 years than at 2 years (18-30% vs 4-22%). The only risk factor for decline both short and long term was DTL resection. In conclusion, most patients had stable verbal memory postoperatively. A few DTL patients had a lasting decline at long-term follow-up, but more patients showed partial recovery, especially in the NDTL group. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Temporal summaries: supporting temporal categorical searching, aggregation and comparison.

    PubMed

    Wang, Taowei David; Plaisant, Catherine; Shneiderman, Ben; Spring, Neil; Roseman, David; Marchand, Greg; Mukherjee, Vikramjit; Smith, Mark

    2009-01-01

    When analyzing thousands of event histories, analysts often want to see the events as an aggregate to detect insights and generate new hypotheses about the data. An analysis tool must emphasize both the prevalence and the temporal ordering of these events. Additionally, the analysis tool must also support flexible comparisons to allow analysts to gather visual evidence. In a previous work, we introduced align, rank, and filter (ARF) to accentuate temporal ordering. In this paper, we present temporal summaries, an interactive visualization technique that highlights the prevalence of event occurrences. Temporal summaries dynamically aggregate events in multiple granularities (year, month, week, day, hour, etc.) for the purpose of spotting trends over time and comparing several groups of records. They provide affordances for analysts to perform temporal range filters. We demonstrate the applicability of this approach in two extensive case studies with analysts who applied temporal summaries to search, filter, and look for patterns in electronic health records and academic records.

  19. Temporal and statistical information in causal structure learning.

    PubMed

    McCormack, Teresa; Frosch, Caren; Patrick, Fiona; Lagnado, David

    2015-03-01

    Three experiments examined children's and adults' abilities to use statistical and temporal information to distinguish between common cause and causal chain structures. In Experiment 1, participants were provided with conditional probability information and/or temporal information and asked to infer the causal structure of a 3-variable mechanical system that operated probabilistically. Participants of all ages preferentially relied on the temporal pattern of events in their inferences, even if this conflicted with statistical information. In Experiments 2 and 3, participants observed a series of interventions on the system, which in these experiments operated deterministically. In Experiment 2, participants found it easier to use temporal pattern information than statistical information provided as a result of interventions. In Experiment 3, in which no temporal pattern information was provided, children from 6- to 7-years-old, but not younger children, were able to use intervention information to make causal chain judgments, although they had difficulty when the structure was a common cause. The findings suggest that participants, and children in particular, may find it more difficult to use statistical information than temporal pattern information because of its demands on information processing resources. However, there may also be an inherent preference for temporal information. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  20. Temporal characterization of a multi-wavelength Brillouin-erbium fiber laser

    NASA Astrophysics Data System (ADS)

    Lambin Iezzi, Victor; Büttner, Thomas F. S.; Tehranchi, Amirhossein; Loranger, Sébastien; Kabakova, Irina V.; Eggleton, Benjamin J.; Kashyap, Raman

    2016-05-01

    This paper provides the first detailed temporal characterization of a multi-wavelength-Brillouin-erbium fiber laser (MWBEFL) by measuring the optical intensity of the individual frequency channels with high temporal resolution. It is found that the power in each channel is highly unstable due to the excitation of several cavity modes for typical conditions of operation. Also provided is the real-time measurements of the MWBEFL output power for two configurations that were previously reported to emit phase-locked picosecond pulse trains, concluded from their autocorrelation measurements. Real-time measurements reveal a high degree of instability without the formation of a stable pulse train. Finally, we model the MWBEFL using coupled wave equations describing the evolution of the Brillouin pump, Stokes and acoustic waves in the presence of stimulated Brillouin scattering, and the optical Kerr effect. A good qualitative consistency between the simulation and experimental results is evident, in which the interference signal at the output shows strong instability as well as the chaotic behavior due to the dynamics of participating pump and Stokes waves.

  1. Tungsten Stable Isotope Compositions of Ferromanganese Crusts

    NASA Astrophysics Data System (ADS)

    Abraham, K.; Barling, J.; Hein, J. R.; Schauble, E. A.; Halliday, A. N.

    2014-12-01

    We report the first accurate and precise data for mass-dependent fractionation of tungsten (W) stable isotopes, using a double spike technique and MC-ICPMS. Results are expressed relative to the NIST 3136 W isotope standard as per mil deviations in 186W/184W (δ186W). Although heavy element mass-dependent fractionations are expected to be small, Tl and U both display significant low temperature isotopic fractionations. Theoretical calculations indicate that W nuclear volume isotopic effects should be smaller than mass-dependent fractionations at low temperatures. Hydrogenetic ferromanganese (Fe-Mn) crusts precipitate directly from seawater and have been used as paleoceanographic recorders of temporal changes in seawater chemistry. Crusts are strongly enriched in W and other metals, and are a promising medium for exploring W isotopic variability. Tungsten has a relatively long residence time in seawater of ~61,000 years, mainly as the tungstate ion (WO42-). Water depth profiles show conservative behaviour. During adsorption on Fe-Mn crusts, W species form inner-sphere complexes in the hexavalent (W6+) state. The major host phase is thought to be Mn oxides and the lighter W isotope is expected to be absorbed preferentially. Surface scrapings of 13 globally distributed hydrogenetic Fe-Mn crusts display δ186W from -0.08 to -0.22‰ (±0.03‰, 2sd). A trend toward lighter W isotope composition exists with increasing water depth (~1500 to ~5200m) and W concentration. One hydrothermal Mn-oxide sample is anomalously light and Mn nodules are both heavy and light relative to Fe-Mn crusts. Tungsten speciation depends on concentration, pH, and time in solution and is not well understood because of the extremely slow kinetics of the reactions. In addition, speciation of aqueous and/or adsorbed species might be sensitive to pressure, showing similar thermodynamic stability but different effective volumes. Thus, W stable isotopes might be used as a water-depth barometer in

  2. TOODM: A temporal object-oriented data model with temporal constraints

    SciTech Connect

    Rose, E.; Segev, A.

    1991-04-01

    A static Entity-Relationship (ER) or static Extended ER (EER) data model is not sufficient for representing the underlying time component of the data, more complex data types as found in planning, design and office automation applications or the operation required for this complex data. The decreasing cost of mass storage devices accompanied by an increased need for real-time systems and easier access to historical and planning data has made the study of the temporal aspects of data models more interesting both theoretically and practically. Furthermore, the ER-based data models can capture relationships between classes but they do not understand the object-oriented paradigm since they treat application-specific relationships and paradigm-specific relationships such as inheritance in the same manner. This shortcoming accompanied by a lack of support for the time dimension results in the specification of temporal relationships and constraints at the application level and often leads to inconsistencies in the data. In this paper, we extend the object-based ER model into a temporal, object-oriented model, incorporate temporal structures and constraints in the data model and propose a temporal, object-oriented query language for the model.

  3. Temporal Variations in Jupiter's Atmosphere

    NASA Technical Reports Server (NTRS)

    Simon-Miller, Amy A.; Chanover, N. J.; Yanamandra-Fisher, P.; Hammel, H. B.; dePater, I.; Noll, K.; Wong, M.; Clarke, J.; Sanchez-Levega, A.; Orton, G. S.; Gonzaga, S.

    2009-01-01

    In recent years, Jupiter has undergone many atmospheric changes from storms turning red to global. cloud upheavals, and most recently, a cornet or asteroid impact. Yet, on top of these seemingly random changes events there are also periodic phenomena, analogous to observed Earth and Saturn atmospheric oscillations. We will present 15 years of Hubble data, from 1994 to 2009, to show how the equatorial tropospheric cloud deck and winds have varied over that time, focusing on the F953N, F41 ON and F255W filters. These filters give leverage on wind speeds plus cloud opacity, cloud height and tropospheric haze thickness, and stratospheric haze, respectively. The wind data consistently show a periodic oscillation near 7-8 S latitude. We will discuss the potential for variations with longitude and cloud height, within the calibration limits of those filters. Finally, we will discuss the role that large atmospheric events, such as the impacts in 1994 and 2009, and the global upheaval of 2007, have on temporal studies, This work was supported by a grant from the NASA Planetary Atmospheres Program. HST observational support was provided by NASA through grants from Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract NAS5-26555.

  4. Temporal Variations in Jupiter's Atmosphere

    NASA Technical Reports Server (NTRS)

    Simon-Miller, Amy A.; Chanover, N. J.; Yanamandra-Fisher, P.; Hammel, H. B.; dePater, I.; Noll, K.; Wong, M.; Clarke, J.; Sanchez-Levega, A.; Orton, G. S.; hide

    2009-01-01

    In recent years, Jupiter has undergone many atmospheric changes from storms turning red to global. cloud upheavals, and most recently, a cornet or asteroid impact. Yet, on top of these seemingly random changes events there are also periodic phenomena, analogous to observed Earth and Saturn atmospheric oscillations. We will present 15 years of Hubble data, from 1994 to 2009, to show how the equatorial tropospheric cloud deck and winds have varied over that time, focusing on the F953N, F41 ON and F255W filters. These filters give leverage on wind speeds plus cloud opacity, cloud height and tropospheric haze thickness, and stratospheric haze, respectively. The wind data consistently show a periodic oscillation near 7-8 S latitude. We will discuss the potential for variations with longitude and cloud height, within the calibration limits of those filters. Finally, we will discuss the role that large atmospheric events, such as the impacts in 1994 and 2009, and the global upheaval of 2007, have on temporal studies, This work was supported by a grant from the NASA Planetary Atmospheres Program. HST observational support was provided by NASA through grants from Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under contract NAS5-26555.

  5. Temporal dosimeter and method

    DOEpatents

    Warner, Benjamin P.; Lopez, Thomas A.

    2003-09-30

    The invention includes a temporal dosimeter. One dosimeter embodiment includes a housing that is opaque to visible light but transparent to ionizing radiation. The dosimeter also includes a sensor for recording dosages of ionizing radiation, a drive mechanism, a power source, and rotatable shields that work together to produce a compound aperture to unveil different portions of the sensor at different times to ionizing radiation. Another dosimeter embodiment includes a housing, a sensor, a shield with an aperture portion, and a linear actuator drive mechanism coupled to the sensor for moving the sensor past the aperture portion. The sensor turns as it moves past the aperture, tracing a timeline record of exposure to ionizing radiation along a helical path on the sensor.

  6. Temporal event sequence simplification.

    PubMed

    Monroe, Megan; Lan, Rongjian; Lee, Hanseung; Plaisant, Catherine; Shneiderman, Ben

    2013-12-01

    Electronic Health Records (EHRs) have emerged as a cost-effective data source for conducting medical research. The difficulty in using EHRs for research purposes, however, is that both patient selection and record analysis must be conducted across very large, and typically very noisy datasets. Our previous work introduced EventFlow, a visualization tool that transforms an entire dataset of temporal event records into an aggregated display, allowing researchers to analyze population-level patterns and trends. As datasets become larger and more varied, however, it becomes increasingly difficult to provide a succinct, summarizing display. This paper presents a series of user-driven data simplifications that allow researchers to pare event records down to their core elements. Furthermore, we present a novel metric for measuring visual complexity, and a language for codifying disjoint strategies into an overarching simplification framework. These simplifications were used by real-world researchers to gain new and valuable insights from initially overwhelming datasets.

  7. Persistent Temporal Streams

    NASA Astrophysics Data System (ADS)

    Hilley, David; Ramachandran, Umakishore

    Distributed continuous live stream analysis applications are increasingly common. Video-based surveillance, emergency response, disaster recovery, and critical infrastructure protection are all examples of such applications. They are characterized by a variety of high- and low-bandwidth streams as well as a need for analyzing both live and archived streams. We present a system called Persistent Temporal Streams (PTS) that supports a higher-level, domain-targeted programming abstraction for such applications. PTS provides a simple but expressive stream abstraction encompassing transport, manipulation and storage of streaming data. In this paper, we present a system architecture for implementing PTS. We provide an experimental evaluation which shows the system-level primitives can be implemented in a lightweight and high-performance manner, and an application-based evaluation designed to show that a representative high-bandwidth stream analysis application can be implemented relatively simply and with good performance.

  8. Temporal waveguides for optical pulses

    SciTech Connect

    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 in practice. In contrast with the spatial case, the confinement can occur even when the central region has a lower refractive index.

  9. Temporal waveguides for optical pulses

    SciTech Connect

    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 in practice. In contrast with the spatial case, the confinement can occur even when the central region has a lower refractive index.

  10. 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

  11. Ranolazine for stable angina pectoris.

    PubMed

    Salazar, Carlos A; Basilio Flores, Juan E; Veramendi Espinoza, Liz E; Mejia Dolores, Jhon W; Rey Rodriguez, Diego E; Loza Munárriz, César

    2017-02-08

    Stable angina pectoris is a chronic medical condition with significant impact on mortality and quality of life; it can be macrovascular or microvascular in origin. Ranolazine is a second-line anti-anginal drug approved for use in people with stable angina. However, the effects of ranolazine for people with angina are considered to be modest, with uncertain clinical relevance. To assess the effects of ranolazine on cardiovascular and non-cardiovascular mortality, all-cause mortality, quality of life, acute myocardial infarction incidence, angina episodes frequency and adverse events incidence in stable angina patients, used either as monotherapy or as add-on therapy, and compared to placebo or any other anti-anginal agent. We searched CENTRAL, MEDLINE, Embase and the Conference Proceedings Citation Index - Science in February 2016, as well as regional databases and trials registers. We also screened reference lists. Randomised controlled trials (RCTs) which directly compared the effects of ranolazine versus placebo or other anti-anginals in people with stable angina pectoris were eligible for inclusion. Two authors independently selected studies, extracted data and assessed risk of bias. Estimates of treatment effects were calculated using risk ratios (RR), mean differences (MD) and standardised mean differences (SMD) with 95% confidence intervals (CI) using a fixed-effect model. Where we found statistically significant heterogeneity (Chi² P < 0.10), we used a random-effects model for pooling estimates. Meta-analysis was not performed where we found considerable heterogeneity (I² ≥ 75%). We used GRADE criteria to assess evidence quality and the GRADE profiler (GRADEpro GDT) to import data from Review Manager 5.3 to create 'Summary of findings' tables. We included 17 RCTs (9975 participants, mean age 63.3 years). We found very limited (or no) data to inform most planned comparisons. Summary data were used to inform comparison of ranolazine versus placebo. Overall

  12. Persistence Length of Stable Microtubules

    NASA Astrophysics Data System (ADS)

    Hawkins, Taviare; Mirigian, Matthew; Yasar, M. Selcuk; Ross, Jennifer

    2011-03-01

    Microtubules are a vital component of the cytoskeleton. As the most rigid of the cytoskeleton filaments, they give shape and support to the cell. They are also essential for intracellular traffic by providing the roadways onto which organelles are transported, and they are required to reorganize during cellular division. To perform its function in the cell, the microtubule must be rigid yet dynamic. We are interested in how the mechanical properties of stable microtubules change over time. Some ``stable'' microtubules of the cell are recycled after days, such as in the axons of neurons or the cilia and flagella. We measured the persistence length of freely fluctuating taxol-stabilized microtubules over the span of a week and analyzed them via Fourier decomposition. As measured on a daily basis, the persistence length is independent of the contour length. Although measured over the span of the week, the accuracy of the measurement and the persistence length varies. We also studied how fluorescently-labeling the microtubule affects the persistence length and observed that a higher labeling ratio corresponded to greater flexibility. National Science Foundation Grant No: 0928540 to JLR.

  13. Stellar Temporal Intensity Interferometry

    NASA Astrophysics Data System (ADS)

    Kian, Tan Peng

    Stellar intensity interferometry was developed by Hanbury-Brown & Twiss [1954, 1956b, 1957, 1958] to bypass the diffraction limit of telescope apertures, with successful measurements including the determination of 32 stellar angular diameters using the Narrabri Stellar Intensity Interferometer [Hanbury-Brown et al., 1974]. This was achieved by measuring the intensity correlations between starlight received by a pair of telescopes separated by varying baselines b which, by invoking the van Cittert-Zernicke theorem [van Cittert, 1934; Zernicke, 1938], are related to the angular intensity distributions of the stellar light sources through a Fourier transformation of the equal-time complex degree of coherence gamma(b) between the two telescopes. This intensity correlation, or the second order correlation function g(2) [Glauber, 1963], can be described in terms of two-photoevent coincidence measurements [Hanbury-Brown, 1974] for our use of photon-counting detectors. The application of intensity interferometry in astrophysics has been largely restricted to the spatial domain but not found widespread adoption due to limitations by its signal-to-noise ratio [Davis et al., 1999; Foellmi, 2009; Jensen et al., 2010; LeBohec et al., 2008, 2010], although there is a growing movement to revive its use [Barbieri et al., 2009; Capraro et al., 2009; Dravins & Lagadec, 2014; Dravins et al., 2015; Dravins & LeBohec, 2007]. In this thesis, stellar intensity interferometry in the temporal domain is investigated instead. We present a narrowband spectral filtering scheme [Tan et al., 2014] that allows direct measurements of the Lorentzian temporal correlations, or photon bunching, from the Sun, with the preliminary Solar g(2)(tau = 0) = 1.3 +/- 0.1, limited mostly by the photon detector response [Ghioni et al., 2008], compared to the theoretical value of g(2)(0) = 2. The measured temporal photon bunching signature of the Sun exceeded the previous records of g(2)(0) = 1.03 [Karmakar et al

  14. [Temporal meaning of suffering].

    PubMed

    Porée, J

    2015-09-01

    If we had to find a few simple words to express what a suffering human being experiences, no matter what ills are causing the suffering and no matter what circumstances underlie the ills themselves, we could unmistakably say that it is the experience of not being able to go on like this. Suffering can be described, in this same sense, as an alteration in temporality. However, describing suffering as such only makes sense if we already have a conception of normal temporality. Yet for this, philosophical tradition offers not one but four competing conceptions. In the present article, we begin by briefly presenting these different conceptions. We then show how each one sheds light, by way of contrast, on a phenomenon whose meaning thus appears to be essentially negative. But does this phenomenon have a negative meaning only? Doesn't it correspond as much to a transformation as an alteration of temporality? This is what we will strive to establish in the third part of the article by relating suffering to hope, in a paradoxical sense of the term. Of the four conceptions of time likely to shed a contrasting light on the upheavals that suffering introduces into our life experience, the one described by Aristotle in Physics is historically the first. In particular, the notion of succession originates therein. But this conception does not account for what makes time the unit of a past, a present, and a future. In Book XI of Confessions, St. Augustine situated this unit not in nature but in the human mind. Hence, his definition of time as a distension of the soul and the necessary division into physical time and psychic time it entails. Husserl's Lessons on the phenomenology of the consciousness of internal time lend credit to this division, but they illuminate only the internal constitution of the "present", which is at the heart of the psychological conception of time. In Being and Time, Heidegger breaks away from this long-standing tradition; in his view, physical time

  15. Operation Condition Monitoring using Temporal Weighted Dempster-Shafer Theory

    DTIC Science & Technology

    2014-12-23

    Theory, Binghamton University, Binghamton, NY Garvin , D., (1988). Managing quality . NY: Free Press. Yu , D,. Frincke, D., (2005). Alert Confidence...timeliness. Outdated informat ion as one of three kind of major informat ion problems ( Garvin , 1988), is not sufficiently fo r the task of fault...HEALTH MANAGEMENT SOCIETY 2014 770 ANNUAL CONFERENCE OF THE PROGNOSTICS AND HEALTH M ANAGEMENT SOCIETY 2014 2 2. METHODOLOGY 2.1. D-S evidence theory

  16. Temporal Representation in Semantic Graphs

    SciTech Connect

    Levandoski, J J; Abdulla, G M

    2007-08-07

    A wide range of knowledge discovery and analysis applications, ranging from business to biological, make use of semantic graphs when modeling relationships and concepts. Most of the semantic graphs used in these applications are assumed to be static pieces of information, meaning temporal evolution of concepts and relationships are not taken into account. Guided by the need for more advanced semantic graph queries involving temporal concepts, this paper surveys the existing work involving temporal representations in semantic graphs.

  17. A Stable Geodetic Reference Frame within the COCONET Footprint to Enable High-Accuracy Ground Deformation Study

    NASA Astrophysics Data System (ADS)

    Liu, H.; Wang, G.; Yu, J.

    2014-12-01

    COCONET(Continuously Operating Caribbean GPS Observational Network) is a multidisciplinary research infrastructure focused on improving the ability to understand, predict, and prepare for multiple natural hazards in the Caribbean, Central America, and Northern Andes. GPS data alone cannot provide accurate ground deformation information over time and space. A precise regional reference frame is needed in interpolating GPS observations to address regional and local ground deformations. Failure to use a precise reference frame would cause unintended negative consequences. The mainly purpose of this study is to establish a stable geodetic reference frame within the COCONet footprint (abbreviated as "COCONet-RF") and to provide positional time series and velocities (relative to COCONet-RF) of all permanent GPS stations within the COCONet footprint to the public. The GIPSY software package was used to calculate position within IGS08. The local reference frame was realized by a 14-parameter Helmert transformation technique. It will be periodically updated in order to synchronize with the update of the IGS reference frame. This stable COCONer-RF would provide a higher accuracy geodetic infrastructure for delineating the magnitude and spatial and temporal variations of ground deformations associated with landslides, faulting, subsidence, and volcanoes. Researchers who are not familiar with GPS data processing and reference transformation will be able to directly integrate COCONET products into their specific research.

  18. Reaction diffusion equation with spatio-temporal delay

    NASA Astrophysics Data System (ADS)

    Zhao, Zhihong; Rong, Erhua

    2014-07-01

    We investigate reaction-diffusion equation with spatio-temporal delays, the global existence, uniqueness and asymptotic behavior of solutions for which in relation to constant steady-state solution, included in the region of attraction of a stable steady solution. It is shown that if the delay reaction function satisfies some conditions and the system possesses a pair of upper and lower solutions then there exists a unique global solution. In terms of the maximal and minimal constant solutions of the corresponding steady-state problem, we get the asymptotic stability of reaction-diffusion equation with spatio-temporal delay. Applying this theory to Lotka-Volterra model with spatio-temporal delay, we get the global solution asymptotically tend to the steady-state problem's steady-state solution.

  19. The temporal variation of redox potentials in peatlands

    NASA Astrophysics Data System (ADS)

    Vorenhout, Michel; Dorau, Kristof; van der Geest, Harm G.

    2017-04-01

    The redox potential (Eh) of peatland soils is an important indicator for potential biogeochemical processes. Currently it is custom to measure the Eh semi-continuous at more than one depth. The time series that come out of these measurements can show high variability, but at times the redox potential is very stable over time. This poster presents some examples of this variability and discusses the greatest causes for temporal temporal variability. Data from measurements in peatlands in Scandinavia, Germany and the Netherlands are presented. We will show that temporal variation of Eh can be used to estimate biogeochemical functioning of wetland soils and that variability is more informative than the absolute value by itself.

  20. 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

  1. Temporal Adverbials in Text Structuring: On Temporal Text Strategy.

    ERIC Educational Resources Information Center

    Virtanen, Tuija

    This paper discusses clause-initial adverbials of time functioning as signals of the temporal text strategy. A chain of such markers creates cohesion and coherence by forming continuity in the text and also signals textual boundaries that occur on different hierarchic levels. The temporal text strategy is closely associated with narrative text.…

  2. 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.

  3. Medical Temporal-Knowledge Discovery via Temporal Abstraction

    PubMed Central

    Moskovitch, Robert; Shahar, Yuval

    2009-01-01

    Medical knowledge includes frequently occurring temporal patterns in longitudinal patient records. These patterns are not easily detectable by human clinicians. Current knowledge could be extended by automated temporal data mining. However, multivariate time-oriented data are often present at various levels of abstraction and at multiple temporal granularities, requiring a transformation into a more abstract, yet uniform dimension suitable for mining. Temporal abstraction (of both the time and value dimensions) can transform multiple types of point-based data into a meaningful, time-interval-based data representation, in which significant, interval-based temporal patterns can be discovered. We introduce a modular, fast time-interval mining method, KarmaLego, which exploits the transitivity inherent in temporal relations. We demonstrate the usefulness of KarmaLego in finding meaningful temporal patterns within a set of records of diabetic patients; several patterns seem to have a different frequency depending on gender. We also suggest additional uses of the discovered patterns for temporal clustering of the mined population and for classifying multivariate time series. PMID:20351898

  4. 2. View of stable looking south with garage/stable to the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. View of stable looking south with garage/stable to the right and paddock fence to the left - Richmond Hill Plantation, Stable/Garage, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  5. 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.

  6. Temporal organization of English clear and conversational speech1

    PubMed Central

    Smiljanić, Rajka; Bradlow, Ann R.

    2008-01-01

    This study investigated the effect of hyperarticulated, intelligibility-enhancing clear speech on temporal characteristics as reflected in number, durations, and variability of consonant and vowel intervals in sentence- and paragraph-length utterances. The results of sentence-in-noise listening tests showed a consistent clear speech intelligibility gain across the utterances of varying complexity indicating that the talkers successfully maintained clear speech articulatory modifications throughout longer stretches of speech. The acoustic analysis revealed that some temporal restructuring accompanied changes in speaking style. This temporal restructuring was observed in the insertion of consonant and vowel segments that were dropped or coarticulated in conversational speech and in an increase in the number of prosodic phrases for clear speech. Importantly, coefficients of variation (variation of consonantal and vocalic intervals normalized for changes in speaking rate) for both consonantal and vowel intervals remained stable in the two speaking styles. Overall, these results suggest that increased intelligibility of clear speech may be attributed to prosodic structure enhancement (increased phrasing and enhanced segmentability) and stable global temporal properties. PMID:19045801

  7. Mixture of Skewed α-Stable Distributions

    NASA Astrophysics Data System (ADS)

    Shojaei, S. R. Hosseini; Nassiri, V.; Mohammadian, Gh. R.; Mohammadpour, A.

    2011-03-01

    Expectation maximization (EM) algorithm and the Bayesian techniques are two approaches for statistical inference of mixture models [3, 4]. By noting the advantages of the Bayesian methods, practitioners prefer them. However, implementing Markov chain Monte Carlo algorithms can be very complicated for stable distributions, due to the non-analytic density or distribution function formulas. In this paper, we introduce a new class of mixture of heavy-tailed distributions, called mixture of skewed stable distributions. Skewed stable distributions belongs to the exponential family and they have analytic density representation. It is shown that skewed stable distributions dominate skew stable distribution functions and they can be used to model heavy-tailed data. The class of skewed stable distributions has an analytic representation for its density function and the Bayesian inference can be done similar to the exponential family of distributions. Finally, mixture of skewed stable distributions are compared to the mixture of stable distributions through a simulations study.

  8. On the Formation of a Stable Penumbra in a Region of Flux Emergence in the Sun

    NASA Astrophysics Data System (ADS)

    Murabito, M.; Romano, P.; Guglielmino, S. L.; Zuccarello, F.

    2017-01-01

    We studied the formation of the first penumbral sector around a pore in the following polarity of the NOAA Active Region (AR) 11490. We used a high spatial, spectral, and temporal resolution data set acquired by the Interferometric BIdimensional Spectrometer operating at the NSO/Dunn Solar Telescope, as well as data taken by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory satellite. On the side toward the leading polarity, elongated granules in the photosphere and an arch filament system (AFS) in the chromosphere are present, while the magnetic field shows a sea-serpent configuration, indicating a region of magnetic flux emergence. We found that the formation of a stable penumbra in the following polarity of the AR begins in the area facing the opposite polarity located below the AFS in the flux emergence region, different from what was found by Schlichenmaier and colleagues. Moreover, during the formation of the first penumbral sector, the area characterized by magnetic flux density larger than 900 G and the area of the umbra increase.

  9. 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.

  10. 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.

  11. Dimensionally stable metallic hydride composition

    DOEpatents

    Heung, Leung K.

    1994-01-01

    A stable, metallic hydride composition and a process for making such a composition. The composition comprises a uniformly blended mixture of a metal hydride, kieselguhr, and a ballast metal, all in the form of particles. The composition is made by subjecting a metal hydride to one or more hydrogen absorption/desorption cycles to disintegrate the hydride particles to less than approximately 100 microns in size. The particles are partly oxidized, then blended with the ballast metal and the kieselguhr to form a uniform mixture. The mixture is compressed into pellets and calcined. Preferably, the mixture includes approximately 10 vol. % or more kieselguhr and approximately 50 vol. % or more ballast. Metal hydrides that can be used in the composition include Zr, Ti, V, Nb, Pd, as well as binary, tertiary, and more complex alloys of La, Al, Cu, Ti, Co, Ni, Fe, Zr, Mg, Ca, Mn, and mixtures and other combinations thereof. Ballast metals include Al, Cu and Ni.

  12. Stable density stratification solar pond

    NASA Technical Reports Server (NTRS)

    Lansing, F. L. (Inventor)

    1985-01-01

    A stable density-stratification solar pond for use in the collection and storage of solar thermal energy including a container having a first section characterized by an internal wall of a substantially cylindrical configuration and a second section having an internal wall of a substantially truncated conical configuration surmounting the first section in coaxial alignment therewith, the second section of said container being characterized by a base of a diameter substantially equal to the diameter of the first section and a truncated apex defining a solar energy acceptance opening is discussed. A body of immiscible liquids is disposed within the container and comprises a lower portion substantially filling the first section of the container and an upper portion substantially filling the second section of the container, said lower portion being an aqueous based liquid of a darker color than the upper portion and of a greater density. A protective cover plate is removably provided for covering the acceptance opening.

  13. Stable States of Biological Organisms

    NASA Astrophysics Data System (ADS)

    Yukalov, V. I.; Sornette, D.; Yukalova, E. P.; Henry, J.-Y.; Cobb, J. P.

    2009-04-01

    A novel model of biological organisms is advanced, treating an organism as a self-consistent system subject to a pathogen flux. The principal novelty of the model is that it describes not some parts, but a biological organism as a whole. The organism is modeled by a five-dimensional dynamical system. The organism homeostasis is described by the evolution equations for five interacting components: healthy cells, ill cells, innate immune cells, specific immune cells, and pathogens. The stability analysis demonstrates that, in a wide domain of the parameter space, the system exhibits robust structural stability. There always exist four stable stationary solutions characterizing four qualitatively differing states of the organism: alive state, boundary state, critical state, and dead state.

  14. Stable massive particles at colliders

    SciTech Connect

    Fairbairn, M.; Kraan, A.C.; Milstead, D.A.; Sjostrand, T.; Skands, P.; Sloan, T.; /Lancaster U.

    2006-11-01

    We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

  15. Are Ionic Liquids Chemically Stable?

    PubMed

    Wang, Binshen; Qin, Li; Mu, Tiancheng; Xue, Zhimin; Gao, Guohua

    2017-02-27

    Ionic liquids have attracted a great deal of interest in recent years, illustrated by their applications in a variety of areas involved with chemistry, physics, biology, and engineering. Usually, the stabilities of ionic liquids are highlighted as one of their outstanding advantages. However, are ionic liquids really stable in all cases? This review covers the chemical stabilities of ionic liquids. It focuses on the reactivity of the most popular imidazolium ionic liquids at structural positions, including C2 position, N1 and N3 positions, and C4 and C5 positions, and decomposition on the imidazolium ring. Additionally, we discuss decomposition of quaternary ammonium and phosphonium ionic liquids and hydrolysis and nucleophilic reactions of anions of ionic liquids. The review aims to arouse caution on potential decomposition of ionic liquids and provides a guide for better utilization of ionic liquids.

  16. Stable line defects in silicene

    NASA Astrophysics Data System (ADS)

    Ghosh, Dibyajyoti; Parida, Prakash; Pati, Swapan K.

    2015-11-01

    Line defects in two-dimensional (2D) materials greatly modulate various properties of their pristine form. Using ab initio molecular dynamics (AIMD) simulations, we investigate the structural reconstructions of different kinds of grain boundaries in the silicene sheets. It is evident that depending upon the presence of silicon adatoms and edge shape of grain boundaries (i.e., armchair or zigzag), stable extended line defects (ELDs) can be introduced in a controlled way. Further studies show the stability of these line-defects in silicene, grown on Ag(111) surface at room-temperature. Importantly, unlike most of the 2D sheet materials such as graphene and hexagonal boron nitride, 5-5-8 line defects modify the nonmagnetic semimetallic pristine silicene sheet to spin-polarized metal. As ferromagnetically ordered magnetic moments remain strongly localized at the line defect, a one-dimensional spin channel gets created in silicene. Interestingly, these spin channels are quite stable because, unlike the edge of nanoribbons, structural reconstruction or contamination cannot destroy the ordering of magnetic moments here. Zigzag silicene nanoribbons with a 5-5-8 line defect also exhibit various interesting electronic and magnetic properties depending upon their width as well as the nature of the magnetic coupling between edge and defect spin states. Upon incorporation of other ELDs, such as 4-4-4 and 4-8 defects, 2D sheets and nanoribbons of silicene show a nonmagnetic metallic or semiconducting ground state. Highlighting the controlled formation of ELDs and consequent emergence of technologically important properties in silicene, we propose new routes to realize silicene-based nanoelectronic and spintronic devices.

  17. Is all inflammation within temporal artery biopsies temporal arteritis?

    PubMed

    Jia, Liwei; Couce, Marta; Barnholtz-Sloan, Jill S; Cohen, Mark L

    2016-11-01

    Temporal arteritis peaks during the eighth decade, affecting patients with frequent comorbidities who are especially prone to adverse effects of corticosteroid therapy. Perivascular inflammation involving small periadventitial vessels is not uncommon in otherwise normal temporal artery biopsies (TABs). As ischemic events occur in patients with non-temporal artery--based inflammation, it has been recommended that any vascular inflammation within TABs be treated with corticosteroids. We sought to determine whether such patients are at increased risk for temporal arteritis-like adverse events compared with age-matched controls devoid of inflammatory infiltrates. TABs without transmural temporal arteritic damage accessioned between 2002 and 2012 were reviewed for inflammation (>15 perivascular lymphocytes) involving small blood vessels and/or temporal artery adventitia. Of 343 TABs, 278 (81%) were negative for transmural arteritis. Inflammation involving small vessels and/or temporal artery adventitia was present in 56 cases (20%). Age-matched controls were available for 39 cases. With a mean follow-up of 5 years (range, 1-11 years), 6/39 (15%) of patients developed stroke or cardiovascular events or died compared with 7/39 (18%) of age-matched controls. None of the patients with study-positive TAB had documented steroid therapy before or after TAB. Our results demonstrate that patients with inflammation involving only small vessels or temporal artery adventitia are not at increased risk for temporal arteritis-like adverse events, and suggest that the risks of protracted corticosteroid therapy in this elderly population likely exceed any potential benefits. We advise against diagnosing vasculitis in the absence of temporal arteritic damage. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Stable CSR in Storage Rings: A Model

    SciTech Connect

    Sannibale, F.

    2005-02-02

    A comprehensive historical view of the work done on coherent synchrotron radiation (CSR) in storage rings is given in reference [1]. Here we want just to point out that even if the issue of CSR in storage rings was already discussed over 50 years ago, it is only recently that a considerable number of observations have been reported. In fact, intense bursts of coherent synchrotron radiation with a stochastic character were measured in the terahertz frequency range, at several synchrotron light source storage rings [2-8]. It has been shown [8-11], that this bursting emission of CSR is associated with a single bunch instability, usually referred as microbunching instability (MBI), driven by the fields of the synchrotron radiation emitted by the bunch itself. Of remarkably different characteristics was the CSR emission observed at BESSY II in Berlin, when the storage ring was tuned into a special low momentum compaction mode [12, 13]. In fact, the emitted radiation was not the quasi-random bursting observed in the other machines, but a powerful and stable flux of broadband CSR in the terahertz range. This was an important result, because it experimentally demonstrated the concrete possibility of constructing a stable broadband source with extremely high power in the terahertz region. Since the publication of the first successful experiment using the ring as a CSR source [14], BESSY II has regular scheduled user's shifts dedicated to CSR experiments. At the present time, several other laboratories are investigating the possibility of a CSR mode of operation [15-17] and a design for a new ring optimized for CSR is at an advanced stage [18]. In what follows, we describe a model that first accounts for the BESSY II observations and then indicates that the special case of BESSY II is actually quite general and typical when relativistic electron storage rings are tuned for short bunches. The model provides a scheme for predicting and optimizing the performance of ring

  19. Stable CSR in storage rings: A model

    SciTech Connect

    Sannibale, Fernando; Byrd, John M.; Loftsdottir, Agusta; Venturini, Marco; Abo-Bakr, Michael; Feikes, Jorge; Holldack, Karsten; Kuske, Peter; Wustefeld, Godehart; Hubers, Heinz-Willerm; Warnock, Robert

    2005-01-03

    A comprehensive historical view of the work done on coherent synchrotron radiation (CSR) in storage rings is given in reference [1]. Here we want just to point out that even if the issue of CSR in storage rings was already discussed over 50 years ago, it is only recently that a considerable number of observations have been reported. In fact, intense bursts of coherent synchrotron radiation with a stochastic character were measured in the terahertz frequency range, at several synchrotron light source storage rings [2-8]. It has been shown [8-11], that this bursting emission of CSR is associated with a single bunch instability, usually referred as microbunching instability (MBI), driven by the fields of the synchrotron radiation emitted by the bunch itself. Of remarkably different characteristics was the CSR emission observed at BESSY II in Berlin, when the storage ring was tuned into a special low momentum compaction mode [12, 13]. In fact, the emitted radiation was not the quasi-random bursting observed in the other machines, but a powerful and stable flux of broadband CSR in the terahertz range. This was an important result, because it experimentally demonstrated the concrete possibility of constructing a stable broadband source with extremely high power in the terahertz region. Since the publication of the first successful experiment using the ring as a CSR source [14], BESSY II has regular scheduled user s shifts dedicated to CSR experiments. At the present time, several other laboratories are investigating the possibility of a CSR mode of operation [15-17] and a design for a new ring optimized for CSR is at an advanced stage [18]. In what follows, we describe a model that first accounts for the BESSY II observations and then indicates that the special case of BESSY II is actually quite general and typical when relativistic electron storage rings are tuned for short bunches. The model provides a scheme for predicting and optimizing the performance of ring

  20. 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...

  1. 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...

  2. Sugar feeding in adult stable flies

    USDA-ARS?s Scientific Manuscript database

    Adult stable flies, (Stomoxys calcitrans (L.)), are known to feed readily on sugars in the laboratory. However, little is known concerning the extent of stable fly sugar feeding in wild populations. We examined the frequency of sugar feeding in stable flies in rural and urban environments. In additi...

  3. A new first-order turbulence mixing model for the stable atmospheric boundary-layer: development and testing in large-eddy and single column models

    NASA Astrophysics Data System (ADS)

    Huang, J.; Bou-Zeid, E.; Golaz, J.

    2011-12-01

    Parameterization of the stably-stratified atmospheric boundary-layer is of crucial importance to different aspects of numerical weather prediction at regional scales and climate modeling at global scales, such as land-surface temperature forecasts, fog and frost prediction, and polar climate. It is well-known that most operational climate models require excessive turbulence mixing of the stable boundary-layer to prevent decoupling of the atmospheric component from the land component under strong stability, but the performance of such a model is unlikely to be satisfactory under weakly and moderately stable conditions. In this study we develop and test a general turbulence mixing model of the stable boundary-layer which works under different stabilities and for steady as well as unsteady conditions. A-priori large-eddy simulation (LES) tests are presented to motivate and verify the new parameterization. Subsequently, an assessment of this model using the GFDL single-column model (SCM) is performed. Idealized test cases including continuously varying stability, as well as stability discontinuity, are used to test the new SCM against LES results. A good match of mean and flux profiles is found when the new parameterization is used, while other traditional first-order turbulence models using the concept of stability function perform poorly. SCM spatial resolution is also found to have little impact on the performance of the new turbulence closure, but temporal resolution is important and a numerical stability criterion based on the model time step is presented.

  4. 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

  5. Effects of temporal fluctuations on mixing

    NASA Astrophysics Data System (ADS)

    Pool, Maria; Dentz, Marco; Post, Vincent E. A.; Simmons, Craig T.

    2016-04-01

    Mixing and dispersion in coastal aquifers are strongly influenced by periodic temporal flow fluctuations on multiple time-scales ranging from days (tides), seasons (pumping and recharge) to glacial cycles (regression and transgressions). Transient forcing effects lead to a complex space- ant time-dependent flow response which induces enhanced spreading and mixing of a dissolved substance. We study effective mixing and solute transport in temporally fluctuating one-dimensional flow for a stable stratification of two fluids of different density. We derive explicit expressions for the concentration distribution and variance to identify the controls and obtain realistic predictions of the coupling between mixing and oscillatory transient flow. We find that the magnitude of transient-driven mixing is mainly controlled by the hydraulic diffusivity, the period and the initial interface location. We also find a spatial dependence of the effective dispersion coefficient which at long times causes the concentration profile to become asymmetric. Sand column experiments under well-controlled laboratory conditions are presented to validate the theoretical effective model defined. The proposed formulation is found to provide very good predictions and correctly reproduces the experimental mixing dynamics.

  6. Interpreting bryophyte stable carbon isotope composition: Plants as temporal and spatial climate recorders

    NASA Astrophysics Data System (ADS)

    Royles, Jessica; Horwath, Aline B.; Griffiths, Howard

    2014-04-01

    are unable to control tissue water content although physiological adaptations allow growth in a wide range of habitats. Carbon isotope signals in two mosses (Syntrichia ruralis and Chorisodontium aciphyllum) and two liverworts (Conocephalum conicum and Marchantia polymorpha), whether instantaneous (real time, Δ13C), or organic matter (as δ13COM), provide an assimilation-weighted summary of bryophyte environmental adaptations. In mosses, δ13COM is within the measured range of Δ13C values, which suggests that other proxies, such as compound-specific organic signals, will be representative of historical photosynthetic and growth conditions. The liverworts were photosynthetically active over a wider range of relative water contents (RWC) than the mosses. There was a consistent 5‰ offset between Δ13C values in C. conicum and M. polymorpha, suggestive of greater diffusion limitation in the latter. Analysis of a C. aciphyllum moss-peat core showed the isotopic composition over the past 200 years reflects recent anthropogenic CO2 emissions. Once corrected for source-CO2 inputs, the seasonally integrated Δ13COM between 1350 and 2000 A.D. varied by 1.5‰ compared with potential range of the 12‰ measured experimentally, demonstrating the relatively narrow range of conditions under which the majority of net assimilation takes place. Carbon isotope discrimination also varies spatially, with a 4‰ shift in epiphytic bryophyte organic matter found between lowland Amazonia and upper montane tropical cloud forest in the Peruvian Andes, associated with increased diffusion limitation.

  7. Chinmo and neuroblast temporal identity.

    PubMed

    Doe, Chris Q

    2006-10-20

    Although spatial patterning during embryonic development is well characterized, a corresponding framework for temporal patterning has not been established. In this issue, Zhu et al. (2006) identify the Chinmo protein as conferring temporal identity on the neural progeny of Drosophila neuroblasts, revealing appealing parallels with spatial patterning.

  8. Spatial Grouping Determines Temporal Integration

    ERIC Educational Resources Information Center

    Hermens, Frouke; Scharnowski, Frank; Herzog, Michael H.

    2009-01-01

    To make sense out of a continuously changing visual world, people need to integrate features across space and time. Despite more than a century of research, the mechanisms of features integration are still a matter of debate. To examine how temporal and spatial integration interact, the authors measured the amount of temporal fusion (a measure of…

  9. Spatial Grouping Determines Temporal Integration

    ERIC Educational Resources Information Center

    Hermens, Frouke; Scharnowski, Frank; Herzog, Michael H.

    2009-01-01

    To make sense out of a continuously changing visual world, people need to integrate features across space and time. Despite more than a century of research, the mechanisms of features integration are still a matter of debate. To examine how temporal and spatial integration interact, the authors measured the amount of temporal fusion (a measure of…

  10. Temporal Predictability Facilitates Causal Learning

    ERIC Educational Resources Information Center

    Greville, W. James; Buehner, Marc J.

    2010-01-01

    "Temporal predictability" refers to the regularity or consistency of the time interval separating events. When encountering repeated instances of causes and effects, we also experience multiple cause-effect temporal intervals. Where this interval is constant it becomes possible to predict when the effect will follow from the cause. In…

  11. Re-examining "temporal niche".

    PubMed

    Smarr, Benjamin L; Schwartz, Michael D; Wotus, Cheryl; de la Iglesia, Horacio O

    2013-07-01

    The circadian system temporally organizes physiology and behavior throughout the 24-h day. At the core of this organization lies a network of multiple circadian oscillators located within the central nervous system as well as in virtually every peripheral organ. These oscillators define a 24-h temporal landscape of mutually interacting circadian rhythms that is known as the temporal niche of a species. This temporal niche is constituted by the collective phases of all biological rhythms emerging from this multi-oscillatory system. We review evidence showing that under different environmental conditions, this system can adopt different harmonic configurations. Thus, the classic chronobiological approach of searching for "the" circadian phase of an animal-typically by studying circadian rhythms of locomotor activity-represents a narrow look into the circadian system of an animal. We propose that the study of hormonal rhythms may lead to a more insightful assessment of a species' temporal niche.

  12. Turbulence Spreading into Linearly Stable Zone and Transport Scaling

    SciTech Connect

    T.S. Hahm; P.H. Diamond; Z. Lin; K. Itoh; S.-I. Itoh

    2003-10-20

    We study the simplest problem of turbulence spreading corresponding to the spatio-temporal propagation of a patch of turbulence from a region where it is locally excited to a region of weaker excitation, or even local damping. A single model equation for the local turbulence intensity I(x, t) includes the effects of local linear growth and damping, spatially local nonlinear coupling to dissipation and spatial scattering of turbulence energy induced by nonlinear coupling. In the absence of dissipation, the front propagation into the linearly stable zone occurs with the property of rapid progression at small t, followed by slower subdiffusive progression at late times. The turbulence radial spreading into the linearly stable zone reduces the turbulent intensity in the linearly unstable zone, and introduces an additional dependence on the rho* is always equal to rho i/a to the turbulent intensity and the transport scaling. These are in broad, semi-quantitative agreements with a number of global gyrokinetic simulation results with zonal flows and without zonal flows. The front propagation stops when the radial flux of fluctuation energy from the linearly unstable region is balanced by local dissipation in the linearly stable region.

  13. 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.

  14. Highly Stable Conjugated Polyelectrolytes for Water-Based Hybrid Mode Electrochemical Transistors.

    PubMed

    Zeglio, Erica; Eriksson, Jens; Gabrielsson, Roger; Solin, Niclas; Inganäs, Olle

    2017-03-16

    Hydrophobic, self-doped conjugated polyelectrolytes (CPEs) are introduced as highly stable active materials for organic electrochemical transistors (OECTs). The hydrophobicity of CPEs renders films very stable in aqueous solutions. The devices operate at gate voltages around zero and show no signs of degradation when operated for 10(4) cycles under ambient conditions. These properties make the produced OECTs ideal devices for applications in bioelectronics.

  15. 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

  16. Temporal context in floristic classification

    NASA Astrophysics Data System (ADS)

    Fitzgerald, R. W.; Lees, B. G.

    1996-11-01

    Multi-temporal remote sensing data present a number of significant problems for the statistical and spatial competence of a classifier. Ideally, a classifier of multi-temporal data should be temporally invariant. It must have the capacity to account for the variations in season, growth cycle, radiometric, and atmospheric conditions at any point in time when classifying the land cover. This paper tests two methods of creating a temporally invariant classifier based on the pattern recognition capabilities of a neural network. A suite of twelve multi-temporal datasets spread over 5 yr along with a comprehensive mix of environmental variables are fused into floristic classification images by the neural network. Uncertainties in the classifications are addressed explicitly with a confidence mask generated from the fuzzy membership value's output by the neural network. These confidence masks are used to produce constrained classification images. The overall accuracy percentage achieved from a study site containing highly disturbed undulating terrain averages 60%. The first method of training, sequential learning of temporal context, is tested by an examination of the step-by-step evolution of the sequential training process. This reveals that the sequential classifier may not have learned about time, because time was constant during each network training session. It also suggests that there are optimal times during the annual cycle to train the classifier for particular floristic classes. The second method of training the classifier is randomised exposure to the entire temporal training suite. Time was now a fluctuating input variable during the network training process. This method produced the best spatially accurate results. The performance of this classifier as a temporally invariant classifier is tested amongst four multi-temporal datasets with encouraging results. The classifier consistently achieved an overall accuracy percentage of 60%. The pairwise predicted

  17. Spatial-temporal data mining

    NASA Astrophysics Data System (ADS)

    Pokrajac, Dragoljub Milos

    Spatial-temporal data mining techniques have become increasingly important in emerging fields such as remote sensing, precision agriculture, geoscience and brain imaging. In this Thesis, novel spatial-temporal data mining methods and algorithms are presented. After the introductory remarks, modeling spatial-temporal attributes with short observation history using spatial-temporal autoregressive models on uniform grid is explored. Model specifications (including covariance structure and stationarity) are discussed as well as issues in model identification, estimation and forecasting on three different sampling schedules. The proposed technique is experimentally evaluated on simulated spatial-temporal processes that confirm to model assumptions as well as on real-life agricultural data. Subsequently, we proceed with spatial-temporal prediction of a response variable with a partial observability of influential attributes. After mathematical definition of the proposed model, evaluation of the estimation technique on synthetic data that conform to the modeling assumptions is performed and a model is assessed on simulated realistic spatial-temporal data, obtained using the proposed data generator. The following part of the Thesis is dedicated to spatial-temporal profit optimization using neural network modeling. Profit optimization is proposed using a two-phase process that consists of estimation of response/attribute dependence and profit optimization for a particular tuple of attribute values. The proposed method is evaluated on simulated precision agriculture data. Next, we introduce a spatial-temporal data simulator, which is an important tool for evaluation of knowledge discovery methods for spatial-temporal domains. Various aspects of the proposed data generator are discussed, including generation of features and simulation of response variable as well as a practical implementation of the proposed method and its application on experiments with simulated data. The

  18. 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

  19. Temporal variability in the deglutition literature.

    PubMed

    Molfenter, Sonja M; Steele, Catriona M

    2012-06-01

    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 upper esophageal sphincter 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.

  20. On nonstable and stable population momentum.

    PubMed

    Espenshade, Thomas J; Olgiati, Analia S; Levin, Simon A

    2011-11-01

    This article decomposes total population momentum into two constituent and multiplicative parts: "nonstable" momentum and "stable" momentum. Nonstable momentum depends on deviations between a population's current age distribution and its implied stable age distribution. Stable momentum is a function of deviations between a population's implied stable and stationary age distributions. In general, the factorization of total momentum into the product of nonstable and stable momentum is a very good approximation. The factorization is exact, however, when the current age distribution is stable or when observed fertility is already at replacement. We provide numerical illustrations by calculating nonstable, stable, and total momentum for 176 countries, the world, and its major regions. In short, the article brings together disparate strands of the population momentum literature and shows how the various kinds of momentum fit together into a single unifying framework.

  1. 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

  2. Ancestry, Temporality, and Potentiality

    PubMed Central

    Gibbon, Sahra

    2014-01-01

    In this paper I examine the variety of ways potential is articulated, entailed, and produced in how the field of cancer genetics is being constituted as a domain of transnational research and an emerging site of health-care intervention in southern Brazil. Drawing on analysis of fieldwork in Brazilian cancer-genetics clinics, I explore how different expressions of potential come to inform dynamically the pursuit of prevention, care, and research as diversely scaled investments for those working and living with cancer-genetics knowledge and technologies. It illustrates how specific temporalities help to constitute and “abductively” frame the meaning of these different potentials particularly as this relates to a focus on ancestry. Colonial histories of migration, the embodied effects of dietary habits, or the moral failings of near and distant ancestors as well as promissory futures and the contingency of lived lives become at different times templates for identifying, materializing, and transforming how the potential of cancer genetics in Brazil is articulated. Potential is also expressed through an idiom of “choice” in different efforts to situate participation in cancer-genetics research as prevention or to negotiate access to basic public health. I explore how these expressions of cancer genetics as potential powerfully yet unevenly work to sustain knowledge practices as well as propel patients and their families into fledgling domains of clinical practice and scientific research. At the same time there is always an “excess of meaning” in these endeavors that make visible lines of fracture and disjuncture in collective efforts to make future histories of and from the pursuit of cancer genetics in southern Brazil. PMID:25018561

  3. The ability of the auditory system to cope with temporal subsampling depends on the hierarchical level of processing.

    PubMed

    Zoefel, Benedikt; Reddy Pasham, Naveen; Brüers, Sasskia; VanRullen, Rufin

    2015-09-09

    Evidence for rhythmic or 'discrete' sensory processing is abundant for the visual system, but sparse and inconsistent for the auditory system. Fundamental differences in the nature of visual and auditory inputs might account for this discrepancy: whereas the visual system mainly relies on spatial information, time might be the most important factor for the auditory system. In contrast to vision, temporal subsampling (i.e. taking 'snapshots') of the auditory input stream might thus prove detrimental for the brain as essential information would be lost. Rather than embracing the view of a continuous auditory processing, we recently proposed that discrete 'perceptual cycles' might exist in the auditory system, but on a hierarchically higher level of processing, involving temporally more stable features. This proposal leads to the prediction that the auditory system would be more robust to temporal subsampling when applied on a 'high-level' decomposition of auditory signals. To test this prediction, we constructed speech stimuli that were subsampled at different frequencies, either at the input level (following a wavelet transform) or at the level of auditory features (on the basis of LPC vocoding), and presented them to human listeners. Auditory recognition was significantly more robust to subsampling in the latter case, that is on a relatively high level of auditory processing. Although our results do not directly demonstrate perceptual cycles in the auditory domain, they (a) show that their existence is possible without disrupting temporal information to a critical extent and (b) confirm our proposal that, if they do exist, they should operate on a higher level of auditory processing.

  4. High Frequency Stable Oscillate boiling

    NASA Astrophysics Data System (ADS)

    Li, Fenfang; Gonzalez-Avila, Silvestre Roberto; Ohl, Claus Dieter

    2015-11-01

    We present an unexpected regime of resonant bubble oscillations on a thin metal film submerged in water, which is continuously heated with a focused CW laser. The oscillatory bubble dynamics reveals a remarkably stable frequency of several 100 kHz and is resolved from the side using video recordings at 1 million frames per second. The emitted sound is measured simultaneously and shows higher harmonics. Once the laser is switched on the water in contact with the metal layer is superheated and an explosively expanding cavitation bubble is generated. However, after the collapse a microbubble is nucleated from the bubble remains which displays long lasting oscillations. Generally, pinch-off from of the upper part of the microbubble is observed generating a continuous stream of small gas bubbles rising upwards. The cavitation expansion, collapse, and the jetting of gas bubbles are detected by the hydrophone and are correlated to the high speed video. We find the bubble oscillation frequency is dependent on the bubble size and surface tension. A preliminary model based on Marangoni flow and heat transfer can explain the high flow velocities observed, yet the origin of bubble oscillation is currently not well understood.

  5. Women Overestimate Temporal Duration: Evidence from Chinese Emotional Words

    PubMed Central

    Zhang, Mingming; Zhang, Lingcong; Yu, Yibing; Liu, Tiantian; Luo, Wenbo

    2017-01-01

    Numerous studies have proven the effect of emotion on temporal perception, using various emotional stimuli. However, research investigating this issue from the lexico-semantic perspective and gender difference remains scarce. In this study, participants were presented with different types of emotional words designed in classic temporal bisection tasks. In Experiment 1 where the arousal level of emotional words was controlled, no pure effect of valence on temporal perception was found; however, we observed the overestimation of women relative to men. Furthermore, in Experiment 2, an orthogonal design of valence and arousal with neutral condition was employed to study the arousal-mechanism of temporal distortion effect and its difference between genders. The results showed that the gender difference observed in Experiment 1 was robust and was not influenced by valence and arousal. Taken together, our findings suggest a stable gender difference in the temporal perception of semantic stimuli, which might be related to some intrinsic properties of linguistic stimuli and sex differences in brain structure as well as physiological features. The automatic processing of time information was also discussed. PMID:28149285

  6. Interictal temporal hypoperfusion is related to early-onset temporal lobe epilepsy.

    PubMed

    Duncan, R; Patterson, J; Hadley, D; Roberts, R; Bone, I

    1996-02-01

    Previous studies of interictal regional cerebral blood flow (rCBF) in temporal lobe epilepsy have shown variable correlations with clinical measures. We used high spatial resolution hexamethyl propyleneamine oxime single photon emission computed tomography (HMPAO SPECT) in 80 consecutive patients with complex partial seizures (CPS), comparing results with those from a large series of normal subjects. Visual image analysis detected abnormalities of rCBF in 41 of 80 (51%; numeric analysis detected abnormalities in 38 of 80). Age at epilepsy onset was significantly younger in patients with temporal hypoperfusion (p = 0.002), and the frequency distribution of hypoperfusion versus age at epilepsy onset was reverse exponential. The results of numerical image analysis showed that degree of hypoperfusion did not vary with age at epilepsy onset. These data suggest a single insult operating early in life as a cause of temporal hypoperfusion, as has been shown for mesial temporal sclerosis (MTS). We could not demonstrate relationships with other clinical variables, including time since last seizure.

  7. Extended temporal cloak based on the inverse temporal Talbot effect.

    PubMed

    Li, Bowen; Wang, Xie; Kang, Jiqiang; Wei, Yuan; Yung, Toni; Wong, Kenneth K Y

    2017-02-15

    A temporal cloak with a significantly extended cloaking window and spatial distribution is created using the inverse temporal Talbot effect. The continuously cloaking window and the total cloaking ratio are 196 ps and 74%, respectively, which are 5.4 and 1.6 times larger than the previous record. Moreover, the cloak is maintained over 5-km of dispersion-compensating fiber (DCF), which enables cloaking temporal events at multiple positions simultaneously. To demonstrate the cloaking performance, both message-encoded and pseudo-random temporal events are successfully concealed. Last, but not least, since our configuration does not require opposite sign of dispersion, the idea can be applied analogously to the spatial domain according to the space-time duality, thus also enriching the spatial cloaking technique.

  8. Low energy stable plasma calibration facility.

    PubMed

    Frederick-Frost, K M; Lynch, K A

    2007-07-01

    We have designed and fabricated a low energy plasma calibration facility for testing and calibration of rocket-borne charged-particle detectors and for the investigation of plasma sheath formation in an environment with ionospheric plasma energies, densities, and Debye lengths. We describe the vacuum system and associated plasma source, which was modified from a Naval Research Laboratory design [Bowles et al. Rev. Sci. Instrum. 67, 455 (1996)]. Mechanical and electrical modifications to this cylindrical microwave resonant source are outlined together with a different method of operating the magnetron that achieves a stable discharge. This facility produces unmagnetized plasmas with densities from 1x10(3)/cm(3) to 6x10(5)/cm(3), electron temperatures from 0.1 to 1.7 eV, and plasma potentials from 0.5 to 8 V depending on varying input microwave power and neutral gas flow. For the range of input microwave power explored (350-600 W), the energy density of the plasma remains constant because of an inverse relationship between density and temperature. This relationship allows a wide range of Debye lengths (0.3-8.4 cm) to be investigated, which is ideal for simulating the ionospheric plasma sheaths we explore.

  9. Stable microbial community composition on the Greenland Ice Sheet.

    PubMed

    Musilova, Michaela; Tranter, Martyn; Bennett, Sarah A; Wadham, Jemma; Anesio, Alexandre M

    2015-01-01

    The first molecular-based studies of microbes in snow and on glaciers have only recently been performed on the vast Greenland Ice Sheet (GrIS). Aeolian microbial seeding is hypothesized to impact on glacier surface community compositions. Localized melting of glacier debris (cryoconite) into the surface ice forms cryoconite holes, which are considered 'hot spots' for microbial activity on glaciers. To date, few studies have attempted to assess the origin and evolution of cryoconite and cryoconite hole communities throughout a melt season. In this study, a range of experimental approaches was used for the first time to study the inputs, temporal and structural transformations of GrIS microbial communities over the course of a whole ablation season. Small amounts of aeolian (wind and snow) microbes were potentially seeding the stable communities that were already present on the glacier (composed mainly of Proteobacteria, Cyanobacteria, and Actinobacteria). However, the dominant bacterial taxa in the aeolian samples (Firmicutes) did not establish themselves in local glacier surface communities. Cryoconite and cryoconite hole community composition remained stable throughout the ablation season following the fast community turnover, which accompanied the initial snow melt. The presence of stable communities in cryoconite and cryoconite holes on the GrIS will allow future studies to assess glacier surface microbial diversity at individual study sites from sampling intervals of short duration only. Aeolian inputs also had significantly different organic δ(13)C values (-28.0 to -27.0‰) from the glacier surface values (-25.7 to -23.6‰), indicating that in situ microbial processes are important in fixing new organic matter and transforming aeolian organic carbon. The continuous productivity of stable communities over one melt season makes them important contributors to biogeochemical nutrient cycling on glaciers.

  10. Stable microbial community composition on the Greenland Ice Sheet

    PubMed Central

    Musilova, Michaela; Tranter, Martyn; Bennett, Sarah A.; Wadham, Jemma; Anesio, Alexandre M.

    2015-01-01

    The first molecular-based studies of microbes in snow and on glaciers have only recently been performed on the vast Greenland Ice Sheet (GrIS). Aeolian microbial seeding is hypothesized to impact on glacier surface community compositions. Localized melting of glacier debris (cryoconite) into the surface ice forms cryoconite holes, which are considered ‘hot spots’ for microbial activity on glaciers. To date, few studies have attempted to assess the origin and evolution of cryoconite and cryoconite hole communities throughout a melt season. In this study, a range of experimental approaches was used for the first time to study the inputs, temporal and structural transformations of GrIS microbial communities over the course of a whole ablation season. Small amounts of aeolian (wind and snow) microbes were potentially seeding the stable communities that were already present on the glacier (composed mainly of Proteobacteria, Cyanobacteria, and Actinobacteria). However, the dominant bacterial taxa in the aeolian samples (Firmicutes) did not establish themselves in local glacier surface communities. Cryoconite and cryoconite hole community composition remained stable throughout the ablation season following the fast community turnover, which accompanied the initial snow melt. The presence of stable communities in cryoconite and cryoconite holes on the GrIS will allow future studies to assess glacier surface microbial diversity at individual study sites from sampling intervals of short duration only. Aeolian inputs also had significantly different organic δ13C values (-28.0 to -27.0‰) from the glacier surface values (-25.7 to -23.6‰), indicating that in situ microbial processes are important in fixing new organic matter and transforming aeolian organic carbon. The continuous productivity of stable communities over one melt season makes them important contributors to biogeochemical nutrient cycling on glaciers. PMID:25852658

  11. An extended SQL for temporal data management in clinical decision-support systems.

    PubMed

    Das, A K; Tu, S W; Purcell, G P; Musen, M A

    1992-01-01

    We are developing a database implementation to support temporal data management for the T-HELPER physician workstation, an advice system for protocol-based care of patients who have HIV disease. To understand the requirements for the temporal database, we have analyzed the types of temporal predicates found in clinical-trial protocols. We extend the standard relational data model in three ways to support these querying requirements. First, we incorporate timestamps into the two-dimensional relational table to store the temporal dimension of both instant- and interval-based data. Second, we develop a set of operations on timepoints and intervals to manipulate timestamped data. Third, we modify the relational query language SQL so that its underlying algebra supports the specified operations on timestamps in relational tables. We show that our temporal extension to SQL meets the temporal data-management needs of protocol-directed decision support.

  12. An extended SQL for temporal data management in clinical decision-support systems.

    PubMed Central

    Das, A. K.; Tu, S. W.; Purcell, G. P.; Musen, M. A.

    1992-01-01

    We are developing a database implementation to support temporal data management for the T-HELPER physician workstation, an advice system for protocol-based care of patients who have HIV disease. To understand the requirements for the temporal database, we have analyzed the types of temporal predicates found in clinical-trial protocols. We extend the standard relational data model in three ways to support these querying requirements. First, we incorporate timestamps into the two-dimensional relational table to store the temporal dimension of both instant- and interval-based data. Second, we develop a set of operations on timepoints and intervals to manipulate timestamped data. Third, we modify the relational query language SQL so that its underlying algebra supports the specified operations on timestamps in relational tables. We show that our temporal extension to SQL meets the temporal data-management needs of protocol-directed decision support. PMID:1482853

  13. Advanced thermally stable jet fuels

    SciTech Connect

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  14. A diversity of synaptic filters are created by temporal summation of excitation and inhibition

    PubMed Central

    George, Andrew A.; Lyons-Warren, Ariel M.; Ma, Xiaofeng; Carlson, Bruce A.

    2011-01-01

    Temporal filtering is a fundamental operation of nervous systems. In peripheral sensory systems, the temporal pattern of spiking activity can encode various stimulus qualities, and temporal filtering allows postsynaptic neurons to detect behaviorally-relevant stimulus features from these spike trains. Intrinsic excitability, short-term synaptic plasticity, and voltage-dependent dendritic conductances have all been identified as mechanisms that can establish temporal filtering behavior in single neurons. Here we show that synaptic integration of temporally-summating excitation and inhibition can establish diverse temporal filters of presynaptic input. Mormyrid electric fish communicate by varying the intervals between electric organ discharges. The timing of each discharge is coded by peripheral receptors into precisely-timed spikes. Within the midbrain posterior exterolateral nucleus, temporal filtering by individual neurons results in selective responses to a particular range of presynaptic interspike intervals. These neurons are diverse in their temporal filtering properties, reflecting the wide range of intervals that must be detected during natural communication behavior. By manipulating presynaptic spike timing with high temporal resolution, we demonstrate that tuning to behaviorally-relevant patterns of presynaptic input is similar in vivo and in vitro. We reveal that GABAergic inhibition plays a critical role in establishing different temporal filtering properties. Further, our results demonstrate that temporal summation of excitation and inhibition establishes selective responses to high and low rates of synaptic input, respectively. Simple models of synaptic integration reveal that variation in these two competing influences provides a basic mechanism for generating diverse temporal filters of synaptic input. PMID:21994388

  15. 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.…

  16. 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.…

  17. Transition operators

    NASA Astrophysics Data System (ADS)

    Alcock-Zeilinger, J.; Weigert, H.

    2017-05-01

    In this paper, we give a generic algorithm of the transition operators between Hermitian Young projection operators corresponding to equivalent irreducible representations of 𝖲𝖴 (N ) , using the compact expressions of Hermitian Young projection operators derived in the work of Alcock-Zeilinger and Weigert [eprint arXiv:1610.10088 [math-ph

  18. Power and reduced temporal discounting.

    PubMed

    Joshi, Priyanka D; Fast, Nathanael J

    2013-04-01

    Decision makers generally feel disconnected from their future selves, an experience that leads them to prefer smaller immediate gains to larger future gains. This pervasive tendency is known as temporal discounting, and researchers across disciplines are interested in understanding how to overcome it. Following recent advances in the power literature, we suggest that the experience of power enhances one's connection with the future self, which in turn results in reduced temporal discounting. In Study 1, we found that participants assigned to high-power roles were less likely than participants assigned to low-power roles to display temporal discounting. In Studies 2 and 3, priming power reduced temporal discounting in monetary and nonmonetary tasks, and, further, connection with the future self mediated the relation between power and reduced discounting. In Study 4, experiencing a general sense of power in the workplace predicted actual lifetime savings. These results have important implications for future research.

  19. Temporal predictability enhances auditory detection

    PubMed Central

    Lawrance, Emma L. A.; Harper, Nicol S.; Cooke, James E.; Schnupp, Jan W. H.

    2015-01-01

    Periodic stimuli are common in natural environments and are ecologically relevant, for example, footsteps and vocalizations. This study reports a detectability enhancement for temporally cued, periodic sequences. Target noise bursts (embedded in background noise) arriving at the time points which followed on from an introductory, periodic “cue” sequence were more easily detected (by ~1.5 dB SNR) than identical noise bursts which randomly deviated from the cued temporal pattern. Temporal predictability and corresponding neuronal “entrainment” have been widely theorized to underlie important processes in auditory scene analysis and to confer perceptual advantage. This is the first study in the auditory domain to clearly demonstrate a perceptual enhancement of temporally predictable, near-threshold stimuli. PMID:24907846

  20. Temporal predictability enhances auditory detection.

    PubMed

    Lawrance, Emma L A; Harper, Nicol S; Cooke, James E; Schnupp, Jan W H

    2014-06-01

    Periodic stimuli are common in natural environments and are ecologically relevant, for example, footsteps and vocalizations. This study reports a detectability enhancement for temporally cued, periodic sequences. Target noise bursts (embedded in background noise) arriving at the time points which followed on from an introductory, periodic "cue" sequence were more easily detected (by ∼1.5 dB SNR) than identical noise bursts which randomly deviated from the cued temporal pattern. Temporal predictability and corresponding neuronal "entrainment" have been widely theorized to underlie important processes in auditory scene analysis and to confer perceptual advantage. This is the first study in the auditory domain to clearly demonstrate a perceptual enhancement of temporally predictable, near-threshold stimuli.

  1. Automated Learning of Temporal Expressions.

    PubMed

    Redd, Douglas; Shaoa, YiJun; Yang, Jing; Divita, Guy; Zeng-Treitler, Qing

    2015-01-01

    Clinical notes contain important temporal information that are critical for making clinical diagnosis and treatment as well as for retrospective analyses. Manually created regular expressions are commonly used for the extraction of temporal information; however, this can be a time consuming and brittle approach. We describe a novel algorithm for automatic learning of regular expressions in recognizing temporal expressions. Five classes of temporal expressions are identified. Keywords specific to those classes are used to retrieve snippets of text representing the same keywords in context. Those snippets are used for Regular Expression Discovery Extraction (REDEx). These learned regular expressions are then evaluated using 10-fold cross validation. Precision and recall are very high, above 0.95 for most classes.

  2. On Nonstable and Stable Population Momentum

    PubMed Central

    Olgiati, Analia S.; Levin, Simon A.

    2014-01-01

    This article decomposes total population momentum into two constituent and multiplicative parts: “nonstable” momentum and “stable” momentum. Nonstable momentum depends on deviations between a population’s current age distribution and its implied stable age distribution. Stable momentum is a function of deviations between a population’s implied stable and stationary age distributions. In general, the factorization of total momentum into the product of nonstable and stable momentum is a very good approximation. The factorization is exact, however, when the current age distribution is stable or when observed fertility is already at replacement. We provide numerical illustrations by calculating nonstable, stable, and total momentum for 176 countries, the world, and its major regions. In short, the article brings together disparate strands of the population momentum literature and shows how the various kinds of momentum fit together into a single unifying framework. PMID:21948106

  3. Usher's syndrome, temporal bone pathology.

    PubMed

    Cremers, C W; Delleman, W J

    1988-10-01

    The histological findings in the right temporal bone of a 65-year-old deaf and blind man are presented. The subject suffered from the autosomal recessive Usher's syndrome, as did 2 of his 5 siblings. They are the offspring of a consanguineous marriage. This man died from an intra-abdominal hemorrhage. Within 3 h after death the temporal bones were donated for study and were processed for histopathological examination.

  4. Effects of temporal dimensional instability on the Advanced X-ray Astrophysics Facility (AXAF-I) high-resolution mirror assembly (HRMA)

    NASA Astrophysics Data System (ADS)

    Cohen, Lester M.

    1995-06-01

    The NASA Advanced X-ray Astrophysics Facility-Imaging (AXAF-I), one of NASA's Great Observatories, will be launched in 1998. The AXAF-I High Resolution Mirror Assembly (HRMA) will provide sub-arc second imaging resolution over the expected mission life of five years. During assembly and operational life of the telescope, small dimensional changes of the structural support system can degrade the telescopes resolving power by introducing unwanted forces. The forces that are introduced depend, in part, on the long term temporal dimensional stability of the materials that are used in the telescope. A year-long stability study carried out at the university of Arizona Dimensional Stability Laboratory recently concluded. Cyanate ester-based composites, 7050-T7451 aluminum, LR-35 invar, 6Al-4V titanium, 6061-T6 aluminum and Zerodur were studied. The Zerodur material was found to be stable to better than 0.03 ppm/yr. The titanium was found to be stable to better than 0.5 ppm/yr. The 7050- T7451 aluminum and cyanate ester-based composites were found relatively unstable but their instability improved significantly with time. Monte-Carlo and deterministic techniques were used to predict the effects of the instability on the telescopes' performance. Temporal instability effects were within the systems top level requirements.

  5. Adaptive GOF residual operation algorithm in video compression

    NASA Astrophysics Data System (ADS)

    Pan, Jiyan; Hu, Bo

    2005-07-01

    Residual operations are introduced in many video compression algorithms to exploit temporal redundancy in video sequences. One of the most effective and computationally simple algorithms is 3D-DWT-SPIHT algorithm. Nevertheless, it only utilizes intra-GOF temporal redundancy. In order to eliminate inter-GOF redundancy, the Simple GOF Residual Operation (SGRO) algorithm was introduced, where residual operations are performed every two GOFs. However, when background mutations occur, the PSNR of reconstructed target GOF significantly drops; on the other hand, when video sequences are temporally stationary, SGRO algorithm fails to fully utilize inter-GOF temporal redundancy due to its imperative insertion of no-residual-operation GOFs. In this paper, we propose a new Adaptive GOF Residual Operation (AGRO) algorithm, based upon a criterion on residual operations, which is derived from an empirical formula of image complexity established by us. AGRO algorithm always selects the best residual operation manner according to the contents of video sequences: by detecting contents of video sequences, it cancels residual operations where background mutations happen, while encouraging residual operations where video sequences are temporally stationary. Therefore, AGRO algorithm prevents the significant drop in compression effects resulted from background mutations, and in the meantime, fully utilizes inter-GOF temporal redundancy. In addition, AGRO algorithm demonstrates an innate error-propagation-resistant property. Numerical results show that AGRO algorithm renders a significant PSNR increase over SGRO algorithm whenever background mutations occur or temporally stationary sequences dominate.

  6. Temporal arteritis in the young.

    PubMed

    McGeoch, Lucy; Silecky, Walter B; Maher, John; Carette, Simon; Pagnoux, Christian

    2013-05-01

    Temporal arteritis in the form of giant cell arteritis (GCA) is common in the elderly but is extremely rare in patients less than 50 years of age. We describe two male patients: one who presented at the age of 31 years with painful, nodular swellings of both temporal arteries and whose temporal artery biopsy demonstrated a non-giant cell panarteritis with mixed inflammatory cell infiltrate typical of juvenile temporal arteritis (JTA); another one, aged 40 years, who presented with headache and cerebral angiography consistent with an intracranial vasculitis and whose temporal artery biopsy confirmed an authentic multinucleated GCA. The first patient spontaneously improved after biopsy and the second patient has responded well to corticosteroid therapy. These two cases exemplify well two distinct but extremely rare forms of temporal arteritis in young patients. A 3rd subset is that associated with a systemic vasculitis. Few cases of JTA have been reported and, to our knowledge, we describe in this report one of the only cases of GCA with central nervous system involvement in the young. Copyright © 2012. Published by Elsevier SAS.

  7. Morphological features of temporal arteritis

    PubMed Central

    Zafar, Saleha; Ko, Jo Mi

    2013-01-01

    Although it varies from center to center, the frequency of temporal artery biopsy in patients suspected of having temporal arteritis (TA) is relatively small. Most commonly, patients suspected of having TA are placed on prednisone for varying periods of time, and if symptoms disappear or lessen the diagnosis is made. During a recent 13-year period at Baylor University Medical Center at Dallas, 15 patients with TA had the diagnosis of TA confirmed by histological examination of a biopsy of one temporal artery. The length of the biopsied artery varied from 0.7 to 5.5 cm (mean 2.7). The 15 patients ranged in age from 68 to 94 years (mean 82, median 85), and 11 (73%) were women. In 13 of the 15 patients (87%), the lumen of the temporal artery was narrowed >95% in cross-sectional area by the panarteritis, and the temporal artery was associated with giant cells in 11 patients (73%). Large collections of erythrocytes were present in the inflamed arterial walls in 5 patients (33%). All 15 patients were treated with varying doses of prednisone with favorable response in each. Eight patients (53%) died from 1 to 105 months (mean 52, median 57) after biopsy of the temporal artery. We have neither positive nor negative evidence that the TA played a role in the patients’ death. Despite the present study and numerous others in the last 70 years, the cause of TA remains a mystery. PMID:23543964

  8. The grounding of temporal metaphors

    PubMed Central

    Lai, Vicky T.; Desai, Rutvik H.

    2016-01-01

    Grounded cognition suggests that the processing of conceptual knowledge cued by language relies on the sensory-motor regions. Does temporal language similarly engage brain areas involved in time perception? Participants read sentences that describe the temporal extent of events with motion verbs (Her seminar stretches across the afternoon) and their static controls. Comparison conditions were fictive motion (Her backyard stretches across the desert) and literal motion (Her arm stretches across the table), along with their static controls. Several time sensitive locations, identified using a meta-analysis, showed activation specific to temporal metaphors, including in the left insula, right claustrum, and bilateral posterior superior temporal sulci. Fictive and literal motion contrasts did not show this difference. Fictive motion contrast showed activation in a conceptual motion sensitive area of the left posterior inferior temporal sulcus. These data suggest that language of time is at least partially grounded in experiential time. In addition, motion semantics has different consequences for events and objects: temporal events become animate, while static entities become motional. PMID:26854961

  9. Temporal binding of interval markers

    PubMed Central

    Derichs, Christina; Zimmermann, Eckart

    2016-01-01

    How we estimate the passage of time is an unsolved mystery in neuroscience. Illusions of subjective time provide an experimental access to this question. Here we show that time compression and expansion of visually marked intervals result from a binding of temporal interval markers. Interval markers whose onset signals were artificially weakened by briefly flashing a whole-field mask were bound in time towards markers with a strong onset signal. We explain temporal compression as the consequence of summing response distributions of weak and strong onset signals. Crucially, temporal binding occurred irrespective of the temporal order of weak and strong onset markers, thus ruling out processing latencies as an explanation for changes in interval duration judgments. If both interval markers were presented together with a mask or the mask was shown in the temporal interval center, no compression occurred. In a sequence of two intervals, masking the middle marker led to time compression for the first and time expansion for the second interval. All these results are consistent with a model view of temporal binding that serves a functional role by reducing uncertainty in the final estimate of interval duration. PMID:27958311

  10. Stable Isotope Analysis of Chlorate

    NASA Astrophysics Data System (ADS)

    Brundrett, M.; Jackson, W. A.; Sturchio, N. C.; Bohlke, J. K.; Hatzinger, P.

    2016-12-01

    Studies have confirmed the presence of chlorate (ClO3-) throughout terrestrial and extraterrestrial systems generally in excess of perchlorate (ClO4-) [1, 2]. ClO3- occurrence, production, and post depositional transformation has significant implications to our understanding of atmospheric Cl cycling and potential biogeochemical reactions on Earth and Mars. The isotopic composition of oxyanions can be used to evaluate their production mechanisms and post-depositional alteration [3, 4]. However, no information is available on the natural isotopic composition of ClO3-. The objective of this study was to develop a method to measure the stable isotope composition (δ18O, δ17O and δ37Cl) of ClO3- and to determine the isotopic composition of ClO3- in natural desert salt accumulations that have been studied previously for NO3- and ClO4- isotopic composition. The process of ClO3- purification and analysis of δ18O, δ 17O and δ37Cl is problematic but has recently been resolved by adapting previously published methods for ClO4-. Competitive anions (e.g. NO3-, Cl-, ClO4-, and SO4-2) are removed through a series of processes including biological reduction, solid phase extraction, and anion or cation exchange. Initial results for control samples treated with the above method have a maximum variation of ± 2 ‰. These methods are being applied to representative samples to determine if various sources of natural and synthetic ClO3- have distinctive isotopic compositions, as reported previously for ClO4- [3, 4]. Establishing the range of isotopic composition of natural ClO3- also could provide information about atmospheric ClO3- production mechanisms and post-depositional processing, with implications for the atmospheric chemistry of oxychlorine compounds and the global biogeochemical cycling of Cl. [1] Jackson et al. (2015) EPSL 430, 470-476. [2] Rao et al. (2010) ES&T 44, 8429-8434. [3] Jackson et al. (2010) ES&T 44, 4869-4876. [4] Bao and Gu (2004) ES&T 38, 5073-5077.

  11. Multiphase pumping - operation & control

    SciTech Connect

    Salis, J. de; Marolies, C. de; Falcimaigne, J.

    1996-12-31

    This paper reviews field issues related to the planning, installation and operation of the helico-axial multiphase pumps. Interest for multiphase production, which leads to simpler and smaller in-field installations, is primarily dictated by the need for more a cost effective production system. Multiphase pumping is essentially a means of adding energy to the unprocessed effluent which enables the liquid/gas mixture to be transported over long distances without the need for prior separation. The Poseidon helico-axial pumps, under normal operating conditions, are largely unaffected by process fluctuations at pump inlet (changes in pressure, liquid or gas flow rate). They have demonstrated a stable behavior (self-adaptive capability with regards to instantaneous changes). A multiphase pump set is designed to operate under changing/fluctuating process conditions. An important issue related to pump operability and flexibility has to do with the driver selection: fixed speed vs. variable speed. In some cases a fixed speed drive provides sufficient operational flexibility. In other cases variable speed can be chosen. Pump operation & control strategies are presented and discussed.

  12. Ultraviolet and thermally stable polymer compositions

    NASA Technical Reports Server (NTRS)

    Adamson, M. J.; Gloria, H. R.; Goldsberry, R. E.; Reinisch, R. F.

    1972-01-01

    Copolymers, produced from aromatic substituted aromatic azine-siloxane compositions, are thermally stable, solar ultraviolet light non-degradable by wavelengths shorter than those reaching earth surface.

  13. Bayesian Inference for Skewed Stable Distributions

    NASA Astrophysics Data System (ADS)

    Shokripour, Mona; Nassiri, Vahid; Mohammadpour, Adel

    2011-03-01

    Stable distributions are a class of distributions which allow skewness and heavy tail. Non-Gaussian stable random variables play the role of normal distribution in the central limit theorem, for normalized sums of random variables with infinite variance. The lack of analytic formula for density and distribution functions of stable random variables has been a major drawback to the use of stable distributions, also in the case of inference in Bayesian framework. Buckle introduced priors for the parameters of stable random variables to obtain an analytic form of posterior distribution. However, many researchers tried to solve the problem, through the Markov chain Monte Carlo methods, e.g. [8] and their references. In this paper a new class of heavy-tailed distribution is introduced, called skewed stable. This class has two main advantages: It has many inferential advantages, since it is a member of exponential family, so the Bayesian inference can be drawn similar to the exponential family of distributions and modelling skew data with stable distributions is dominated by this family. Finally, Bayesian inference for skewed stable arc compared to the stable distributions through a few simulations study.

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

    NASA Astrophysics Data System (ADS)

    Yang, Xiaofeng; Han, Daozhi

    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 proposed schemes.

  15. Schwartz operators

    NASA Astrophysics Data System (ADS)

    Keyl, M.; Kiukas, J.; Werner, R. F.

    2016-05-01

    In this paper, we introduce Schwartz operators as a non-commutative analog of Schwartz functions and provide a detailed discussion of their properties. We equip them, in particular, with a number of different (but equivalent) families of seminorms which turns the space of Schwartz operators into a Fréchet space. The study of the topological dual leads to non-commutative tempered distributions which are discussed in detail as well. We show, in particular, that the latter can be identified with a certain class of quadratic forms, therefore making operations like products with bounded (and also some unbounded) operators and quantum harmonic analysis available to objects which are otherwise too singular for being a Hilbert space operator. Finally, we show how the new methods can be applied by studying operator moment problems and convergence properties of fluctuation operators.

  16. Crew operations

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The requirements for the activities involved, and the procedures used by the crew in the operations of the modular space station are presented. All crew-related characteristics of the station and its operations are indicated. The interior configuration and arrangement of each of the space station modules, the facilities and equipment in the module and their operation are described as related to crew habitability. The crew activities and procedures involved in the operation of the station in the accomplishment of its primary mission are defined. The operations involved in initial station buildup, and the on-orbit operation and maintenance of the station and its subsystems to support the experimental program are included. A general description of experiment operations is also given.

  17. Temporal stability of electrical conductivity in a sandy soil

    NASA Astrophysics Data System (ADS)

    Pedrera-Parrilla, Aura; Brevik, Eric C.; Giráldez, Juan V.; Vanderlinden, Karl

    2016-07-01

    Understanding of soil spatial variability is needed to delimit areas for precision agriculture. Electromagnetic induction sensors which measure the soil apparent electrical conductivity reflect soil spatial variability. The objectives of this work were to see if a temporally stable component could be found in electrical conductivity, and to see if temporal stability information acquired from several electrical conductivity surveys could be used to better interpret the results of concurrent surveys of electrical conductivity and soil water content. The experimental work was performed in a commercial rainfed olive grove of 6.7 ha in the `La Manga' catchment in SW Spain. Several soil surveys provided gravimetric soil water content and electrical conductivity data. Soil electrical conductivity values were used to spatially delimit three areas in the grove, based on the first principal component, which represented the time-stable dominant spatial electrical conductivity pattern and explained 86% of the total electrical conductivity variance. Significant differences in clay, stone and soil water contents were detected between the three areas. Relationships between electrical conductivity and soil water content were modelled with an exponential model. Parameters from the model showed a strong effect of the first principal component on the relationship between soil water content and electrical conductivity. Overall temporal stability of electrical conductivity reflects soil properties and manifests itself in spatial patterns of soil water content.

  18. Turbulence and mixing in the stable atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Yagüe, C.; Morales, G.; Terradellas, E.; Cuxart, J.

    2003-04-01

    Transport and mixing in the Stable Atmospheric Boundary Layer is not well understood yet. However this is an important feature in atmospheric pollution as well as in other environmental studies. A Stable Atmospheric Boundary Layer Experiment in Spain (SABLES98) took place from the 10th to the 28th of September 1998. Two masts (100 m and 10 m) were instrumented with five sonic anemometers, 14 thermocouples, 8 cup anemometers, vanes,radiometers, etc. In addition, a sodar, a tethered balloon and a triangular array of cup anemometers were operating during the campaign. The experiment showed three different regimes, being specially interesting the one between 14th and 21st of September where stable and very stable conditions were present. In this work we present the behaviour of turbulent and stability parameters at several heights. The different evolutions of the Nocturnal Boundary Layer and the main parameters that controle its behaviour are discussed.The influence of internal gravity waves and their interaction with turbulence is also studied using wavelets.

  19. Connecting laboratory behavior to field function through stable isotope analysis.

    PubMed

    Glon, Mael G; Larson, Eric R; Pangle, Kevin L

    2016-01-01

    Inherent difficulties of tracking and observing organisms in the field often leave researchers with no choice but to conduct behavioral experiments under laboratory settings. However, results of laboratory experiments do not always translate accurately to natural conditions. A fundamental challenge in ecology is therefore to scale up from small area and short-duration laboratory experiments to large areas and long durations over which ecological processes generally operate. In this study, we propose that stable isotope analysis may be a tool that can link laboratory behavioral observations to past field interactions or function of individual organisms. We conducted laboratory behavioral assays to measure dominance of invasive rusty crayfish, Orconectes rusticus, and used stable isotope analysis to hindcast trophic positions of these crayfish under preceding natural conditions. We hypothesized that more dominant crayfish in our assays would have higher trophic positions if dominance were related to competitive ability or willingness to pursue high-risk, high-reward prey. We did not find a relationship between crayfish dominance and trophic position, and therefore infer that laboratory dominance of crayfish may not necessarily relate to their ecology in the field. However, this is to our knowledge the first attempt to directly relate laboratory behavior to field performance via stable isotope analysis. We encourage future studies to continue to explore a possible link between laboratory and field behavior via stable isotope analysis, and propose several avenues to do so.

  20. Connecting laboratory behavior to field function through stable isotope analysis

    PubMed Central

    Larson, Eric R.; Pangle, Kevin L.

    2016-01-01

    Inherent difficulties of tracking and observing organisms in the field often leave researchers with no choice but to conduct behavioral experiments under laboratory settings. However, results of laboratory experiments do not always translate accurately to natural conditions. A fundamental challenge in ecology is therefore to scale up from small area and short-duration laboratory experiments to large areas and long durations over which ecological processes generally operate. In this study, we propose that stable isotope analysis may be a tool that can link laboratory behavioral observations to past field interactions or function of individual organisms. We conducted laboratory behavioral assays to measure dominance of invasive rusty crayfish, Orconectes rusticus, and used stable isotope analysis to hindcast trophic positions of these crayfish under preceding natural conditions. We hypothesized that more dominant crayfish in our assays would have higher trophic positions if dominance were related to competitive ability or willingness to pursue high-risk, high-reward prey. We did not find a relationship between crayfish dominance and trophic position, and therefore infer that laboratory dominance of crayfish may not necessarily relate to their ecology in the field. However, this is to our knowledge the first attempt to directly relate laboratory behavior to field performance via stable isotope analysis. We encourage future studies to continue to explore a possible link between laboratory and field behavior via stable isotope analysis, and propose several avenues to do so. PMID:27077010

  1. Temporal disaggregation of daily meteorological grid data

    NASA Astrophysics Data System (ADS)

    Vormoor, K.; Skaugen, T.

    2012-04-01

    For operational flood forecasting, the Norwegian Water Resources and Energy Administration (NVE) applies the conceptual HBV rainfall-runoff model for 117 catchments. The hydrological models are calibrated and run using an extensive meteorological grid data set providing daily temperature and precipitation data back to 1957 for entire Norway at 1x1 km grid resolution (seNorge grids). The daily temporal resolution is dictated by the resolution of historical meteorological data. However, since meteorological forecasts and runoff observations are also available at a much finer than a daily time-resolution (e.g. 6 hourly), and many hydrological extreme events happens at a temporal scale of less than daily, it is important to try to establish a historical dataset of meteorological input at a finer corresponding temporal resolution. We present a simple approach for the temporal disaggregation of the daily meteorological seNorge grids into 6-hour values by consulting a HIRLAM hindcast grid data series with an hourly time resolution and a 10x10 km grid resolution. The temporal patterns of the hindcast series are used to disaggregate the daily interpolated observations from the seNorge grids. In this way, we produce a historical grid dataset from 1958-2010 with 6-hourly temperature and precipitation for entire Norway on a 1x1 km grid resolution. For validation and to see if additional information is gained, the disaggregated data is compared with observed values from selected meteorological stations. In addition, the disaggregated data is evaluated against daily data, simply split into four fractions. The validation results indicate that additional information is indeed gained and point out the benefit of disaggregated data compared to daily data split into four. With regard to temperature, the disaggregated values show very low deviations (MAE, RMSE), and are highly correlated with observed values. Regarding precipitation, the disaggregated data shows cumulative

  2. 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

  3. Classification of acoustically stable areas using empirical orthogonal functions

    NASA Astrophysics Data System (ADS)

    Hjelmervik, Karl Thomas; Jensen, Jan Kristian; Østenstad, Petter; Ommundsen, Atle

    2012-02-01

    Sonar performance modeling is crucial for submarine and anti-submarine operations. The validity of sonar performance models is generally limited by environmental uncertainty, and particularly uncertainty in the vertical sound speed profile (SSP). Rapid environmental assessment (REA) products, such as oceanographic surveys and ocean models may be used to reduce this uncertainty prior to sonar operations. Empirical orthogonal functions (EOF) applied on the SSPs inherently take into account the vertical gradients and therefore the acoustic properties. We present a method that employs EOFs and a grouping algorithm to divide a large group of SSPs from an ocean model simulation into smaller groups with similar SSP characteristics. Such groups are henceforth called acoustically stable groups. Each group represents a subset in space and time within the ocean model domain. Regions with low acoustic variability contain large and geographically contiguous acoustically stable groups. In contrast, small or fragmented acoustically stable groups are found in regions with high acoustic variability. The main output is a map of the group distribution. This is a REA product in itself, but the map may also be used as a planning aid for REA survey missions.

  4. GMRES and integral operators

    SciTech Connect

    Kelley, C.T.; Xue, Z.Q.

    1994-12-31

    Many discretizations of integral equations and compact fixed point problems are collectively compact and strongly convergent in spaces of continuous functions. These properties not only lead to stable and convergent approximations but also can be used in the construction of fast multilevel algorithms. Recently the GMRES algorithm has become a standard coarse mesh solver. The purpose of this paper is to show how the special properties of integral operators and their approximations are reflected in the performance of the GMRES iteration and how these properties can be used to strengthen the norm in which convergence takes place. The authors illustrate these ideas with composite Gauss rules for integral equations on the unit interval.

  5. Recursive implementations of temporal filters for image motion computation.

    PubMed

    Clifford, C W; Langley, K

    2000-05-01

    Efficient algorithms for image motion computation are important for computer vision applications and the modelling of biological vision systems. Intensity-based image motion computation proceeds in two stages: the convolution of linear spatiotemporal filter kernels with the image sequence, followed by the non-linear combination of the filter outputs. If the spatiotemporal extent of the filter kernels is large, then the convolution stage can be very intensive computationally. One effective means of reducing the storage required and computation involved in implementing the temporal convolutions is the introduction of recursive filtering. Non-recursive methods require the number of frames of the image sequence stored at any given time to be equal to the temporal extent of the slowest temporal filter. In contrast, recursive methods encode recent stimulus history implicitly in the values of a small number of variables updated through a series of feedback equations. Recursive filtering reduces the number of values stored in memory during convolution and the number of mathematical operations involved in computing the filters' outputs. This paper extends previous recursive implementations of gradient- and correlation-based motion analysis algorithms [Fleet DJ, Langley K (1995) IEEE PAMI 17: 61-67; Clifford CWG, Ibbotson MR, Langley K (1997) Vis Neurosci 14: 741-749], describing a recursive implementation of causal band-pass temporal filters suitable for use in energy- and phase-based algorithms for image motion computation. It is shown that the filters' temporal frequency tuning curves fit psychophysical estimates of the temporal properties of human visual filters.

  6. Chondroblastoma of the temporal bone: consistent middle fossa involvement.

    PubMed

    Selesnick, S H; Levine, J M

    1999-01-01

    The objective of this study is to describe the presentation and clinical course of two patients with temporal bone chondroblastoma, and to review the literature on temporal bone chondroblastoma to identify characteristic clinical and radiological presentations, and optimal treatment regimens. MEDLINE literature searches covering the period from 1966 to January 1998, in all languages, were performed as well as a review of the bibliographies of the identified studies. Strict inclusion criteria were upheld, In total 18 studies had patients whose data could be analyzed. From the 18 studies, 34 patients were identified, but only 21 cases met the inclusion criteria. Demographic, clinical presentation, radiological, operative and treatment parameters were analyzed in this cohort of patients. Ninety-five percent of patients were found to have invasion of the middle cranial fossa and 76% were found to have erosion into the superior aspect of the external auditory canal by temporal bone chondroblastoma. The characteristic growth pattern of temporal bone chondroblastoma may result from embryonal or cartilagenous rests entrapped in the tympanosquamous suture line in the middle fossa floor. Temporal bone chondroblastoma represents a pathology that does not arise from, or have a growth pattern resembling other pathologies in the temporal bone.

  7. Blood feeding behavior of the stable fly

    USDA-ARS?s Scientific Manuscript database

    Stable fly is a fly that looks similar to a house fly but both sexes are blood feeders. Blood is required for successful fertilization and development of eggs. Bites are painful but there is usually no pain after the fly stops feeding. The stable fly is a persistent feeder and will continue trying t...

  8. Area wide management of stable flies

    USDA-ARS?s Scientific Manuscript database

    Stable flies are among the most damaging pests of livestock worldwide. Their painful bites cause both physiological and behavioral changes that reduce productivity and wellbeing of domestic animals and humans alike. Immature stable flies develop in decomposing and fermenting vegetative materials, of...

  9. Stable spatial solitons in semiconductor optical amplifiers.

    PubMed

    Ultanir, E A; Michaelis, D; Lederer, F; Stegeman, G I

    2003-02-15

    The existence of stable dissipative spatial solitons at low intensities in patterned electrode semiconductor optical amplifiers (SOAs) is predicted theoretically. In contrast to conventional SOAs, this system may support stable solitons because the inherent saturating losses provide subcritical bifurcations for both the plane-wave and the soliton solution.

  10. On stiffly stable implicit linear multistep methods.

    NASA Technical Reports Server (NTRS)

    Cooke, C. H.

    1972-01-01

    The motivation to increase the step size with no degradation of numerical accuracy and stability has led to the discovery of particular members of the class of stiffly stable implicit linear multistep algorithms. Sufficient conditions for a consistent linear multistep method to be stiffly stable are given. These conditions involve properties of the stability mapping from the extended complex plane onto itself.

  11. Stable isotope analyses of palaeo-pollen records

    NASA Astrophysics Data System (ADS)

    Hemming, D.; Loader, N.

    2002-12-01

    Pollen stratigraphy is one of the most widely used tools for studying climate and vegetation dynamics over global and multi-millennial scales. Since the isotopic compositions of photosynthates that are used to form the pollen structure reflect environmental conditions during the time of pollen formation, the stable carbon, oxygen and hydrogen isotopic compositions (δ13C, δ18O and δ{}D) of the pollen grains may reflect this environmental information. Although there are many preliminary tests and methodological problems to overcome before we can fully utilise palaeo-pollen records, it is the general goal of our research to use pollen isotope records together with conventional palynological analyses to provide additional, independent spatial and temporal palaeo-environmental information and to provide new data on terrestrial ecosystem dynamics, including the timing of environmental changes, phase relationships of vegetation responses and regional and temporal variations in δ13C, Δ13C, δ18O and δ{}D. These isotopic records will facilitate in the modelling of palaeo-environments. By separating and analysing different pollen species, including C3 and C4, we also aim to assess species-specific climatic responses. We present results describing some recent investigations concerning the nature of the isotopic signal contained within pollen, the methodological developments we have made to measure the pollen isotopic composition and the future challenges that must be overcome before this potentially powerful quantitative terrestrial palaeo-archive can be fully and correctly utilised.

  12. 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.

  13. Critically stable damping in flexible structure control

    NASA Astrophysics Data System (ADS)

    Xing, Zhigang; Zheng, Gangtie

    2017-10-01

    The concept of critically stable damping and its application to flexible structure control are presented. Critically stable damping was originally noted from the viewpoint of control-structure integration. It was recognized that a slight augmentation of structural damping would result in substantially more robust control without decreased performance and could guarantee the stability margin for any structural frequency increase. This paper illustrates the wide occurrence of critically stable damping phenomenon, establishes its basic relationship for the insight of the general design procedure, and applies the concept into the practical design of a satellite with a large deployable antenna. It is noted that the critically stable damping concept could provide a feasible approach to overcome the difficulty in ultra-large space structure design and control, and enhance the performance of a variety of excellent control design methodologies for flexible structure control. This critically stable damping provides new insight into the integrated design of control and structure.

  14. Shoreline change assessment using multi-temporal satellite images: a case study of Lake Sapanca, NW Turkey.

    PubMed

    Duru, Umit

    2017-08-01

    The research summarized here determines historical shoreline changes along Lake Sapanca by using Remote Sensing (RS) and Geographical Information Systems (GIS). Six multi-temporal satellite images of Landsat Multispectral Scanner (L1-5 MMS), Enhanced Thematic Mapper Plus (L7 ETM+), and Operational Land Imager Sensors (L8 OLI), covering the period between 17 June 1975 and 15 July 2016, were used to monitor shoreline positions and estimate change rates along the coastal zone. After pre-possessing routines, the Normalized Difference Water Index (NDWI), Modified Normalized Difference Water Index (MNDWI), and supervised classification techniques were utilized to extract six different shorelines. Digital Shoreline Analysis System (DSAS), a toolbox that enables transect-based computations of shoreline displacement, was used to compute historical shoreline change rates. The average rate of shoreline change for the entire cost was 2.7 m/year of progradation with an uncertainty of 0.2 m/year. While the great part of the lake shoreline remained stable, the study concluded that the easterly and westerly coasts and deltaic coasts are more vulnerable to shoreline displacements over the last four decades. The study also reveals that anthropogenic activities, more specifically over extraction of freshwater from the lake, cyclic variation in rainfall, and deposition of sediment transported by the surrounding creeks dominantly control spatiotemporal shoreline changes in the region. Monitoring shoreline changes using multi-temporal satellite images is a significant component for the coastal decision-making and management.

  15. Multiprocess network logic with temporal and spatial modalities. revised

    SciTech Connect

    Reif, J.H.; Sistla, A.P.

    1982-10-01

    We introduce a modal logic which can be used to formally reason about synchronous fixed connection multiprocess networks such as VLSI. Our logic has both temporal and spatial modal operators. The various temporal modal operators allow us to relate properties of the current state of a given process with properties of succeeding states of the given process. Also, the spatial modal operators allow us to relate properties of the current state of a given process with properties of the current state of neighboring processes. Many interesting properties for multiprocessor networks can be elegantly expressed in our logic. We give examples of the diverse applications of our logic to packet routing firing squad problems, and systolic algorithms.

  16. Macroscopic hotspots identification: A Bayesian spatio-temporal interaction approach.

    PubMed

    Dong, Ni; Huang, Helai; Lee, Jaeyoung; Gao, Mingyun; Abdel-Aty, Mohamed

    2016-07-01

    This study proposes a Bayesian spatio-temporal interaction approach for hotspot identification by applying the full Bayesian (FB) technique in the context of macroscopic safety analysis. Compared with the emerging Bayesian spatial and temporal approach, the Bayesian spatio-temporal interaction model contributes to a detailed understanding of differential trends through analyzing and mapping probabilities of area-specific crash trends as differing from the mean trend and highlights specific locations where crash occurrence is deteriorating or improving over time. With traffic analysis zones (TAZs) crash data collected in Florida, an empirical analysis was conducted to evaluate the following three approaches for hotspot identification: FB ranking using a Poisson-lognormal (PLN) model, FB ranking using a Bayesian spatial and temporal (B-ST) model and FB ranking using a Bayesian spatio-temporal interaction (B-ST-I) model. The results show that (a) the models accounting for space-time effects perform better in safety ranking than does the PLN model, and (b) the FB approach using the B-ST-I model significantly outperforms the B-ST approach in correctly identifying hotspots by explicitly accounting for the space-time variation in addition to the stable spatial/temporal patterns of crash occurrence. In practice, the B-ST-I approach plays key roles in addressing two issues: (a) how the identified hotspots have evolved over time and (b) the identification of areas that, whilst not yet hotspots, show a tendency to become hotspots. Finally, it can provide guidance to policy decision makers to efficiently improve zonal-level safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Your alliances are too stable.

    PubMed

    Ernst, David; Bamford, James

    2005-06-01

    A 2004 McKinsey survey of more than 30 companies reveals that at least 70% of them have major alliances that are underperforming and in need of restructuring. Moreover, JVs that broaden or otherwise adjust their scope have a 79% success rate, versus 33% for ventures that remain essentially unchanged. Yet most firms don't routinely evaluate the need to overhaul their alliances or intervene to correct performance problems. That means corporations are missing huge opportunities: By revamping just one large alliance, a company can generate 100 million dololars to 300 million dollars in extra income a year. Here's how to unlock more value from alliances: (1) Launch the process. Don't wait until your venture is in the middle of a crisis; regularly scan your major alliances to determine which need restructuring. Once you've targeted one, designate a restructuring team and find a senior sponsor to push the process along. Then delineate the scope of the team's work. (2) Diagnose performance. Evaluate the venture on the following performance dimensions: ownership and financials, strategy, operations, governance, and organization and talent. Identify the root causes of the venture's problems, not just the symptoms, and estimate how much each problem is costing the company. (3) Generate restructuring options. Based on the diagnosis, decide whether to fix, grow, or exit the alliance. Assuming the answer is fix or grow, determine whether fundamental or incremental changes are needed, using the five performance dimensions above as a framework. Then assemble three or four packages of restructuring options, test them with shareholders, and gain parents' approval. (4) Execute the changes. Embark on a widespread and consistent communication effort, building support among executives in the JV and the parent companies. So the process stays on track, assign accountability to certain groups or individuals.

  18. The mechanisms of temporal inference

    NASA Technical Reports Server (NTRS)

    Fox, B. R.; Green, S. R.

    1987-01-01

    The properties of a temporal language are determined by its constituent elements: the temporal objects which it can represent, the attributes of those objects, the relationships between them, the axioms which define the default relationships, and the rules which define the statements that can be formulated. The methods of inference which can be applied to a temporal language are derived in part from a small number of axioms which define the meaning of equality and order and how those relationships can be propagated. More complex inferences involve detailed analysis of the stated relationships. Perhaps the most challenging area of temporal inference is reasoning over disjunctive temporal constraints. Simple forms of disjunction do not sufficiently increase the expressive power of a language while unrestricted use of disjunction makes the analysis NP-hard. In many cases a set of disjunctive constraints can be converted to disjunctive normal form and familiar methods of inference can be applied to the conjunctive sub-expressions. This process itself is NP-hard but it is made more tractable by careful expansion of a tree-structured search space.

  19. Temporal coordination between performing musicians.

    PubMed

    Loehr, Janeen D; Palmer, Caroline

    2011-11-01

    Many common behaviours require people to coordinate the timing of their actions with the timing of others' actions. We examined whether representations of musicians' actions are activated in coperformers with whom they must coordinate their actions in time and whether coperformers simulate each other's actions using their own motor systems during temporal coordination. Pianists performed right-hand melodies along with simple or complex left-hand accompaniments produced by themselves or by another pianist. Individual performers' preferred performance rates were measured in solo performance of the right-hand melody. The complexity of the left-hand accompaniment influenced the temporal grouping structure of the right-hand melody in the same way when it was performed by the self or by the duet partner, providing some support for the action corepresentation hypothesis. In contrast, accompaniment complexity had little influence on temporal coordination measures (asynchronies and cross-correlations between parts). Temporal coordination measures were influenced by a priori similarities between partners' preferred rates; partners who had similar preferred rates in solo performance were better synchronized and showed mutual adaptation to each other's timing during duet performances. These findings extend previous findings of action corepresentation and action simulation to a task that requires precise temporal coordination of independent yet simultaneous actions.

  20. Temporal bone chondroblastoma: a review.

    PubMed

    Bian, Liu-Guan; Sun, Qing-Fang; Zhao, Wei-Guo; Shen, Jian-Kang; Tirakotai, Wuttipong; Bertalanffy, Helmult

    2005-06-01

    The objective of this paper was to review temporal bone chondroblastomas in regard to their presentation, radiographic findings, histopathology, and treatment. A case report of a 38-year-old man who presented with the left-sided hearing impairment and temporal swelling was reviewed. A CT scan revealed an osteolytic lobulated expansile mass. MRI depicted two cystic components with fluid-fluid level and enhanced solid mass. Immunohistochemical study of S-100 was performed using avidinbiotin-complex method. The tumor was totally removed, with eroded squamous bone and temporal muscle, via the left zygomatic-extended middle fossa approach. The pathology of the tumor showed that the tumor cell was spindle-shaped, along with multinucleated giant cells. These cells had oval to polygonal nuclei; some cells showed grooved nuclei. Intercelluar calcification and hemorrhagic components were also observed in the tumor. Tumor cells were strongly positive for S-100 protein. Temporal bone chondroblastomas are extremely rare osseous tumors with only 45 cases previously reported in the published literature. They may be confused with more common lesions seen in the temporal bone. Diagnostic radiology, including CT and/or MRI, as well as immunohistochemical staining with S-100 protein, may assist in making the diagnosis. Treatment is complete surgical excision with preservation of vital neurovascular structures.

  1. Optimization of resistor array infrared projector temporal response

    NASA Astrophysics Data System (ADS)

    Olson, Eric M.; Williams, Owen M.; Thompson, Rhoe A.

    2001-08-01

    The thermal conduction and electronic drive processes that govern the temporal response of resistor array infrared projectors are reviewed. The characteristics and limitations of the voltage overdrive method that can be implemented for sharpening the temporal response are also discussed. Overdrive is shown to be a viable technique provided sufficient drive power and temperature margins are available outside of the normal dynamic range. It is shown also by analysis of overdrive measurements applied to a Honeywell GE snapshot resistor array that practical real-time overdrive processors can be designed to operate consistently with theoretical predictions.

  2. Infections on Temporal Networks—A Matrix-Based Approach

    PubMed Central

    Koher, Andreas; Lentz, Hartmut H. K.; Hövel, Philipp; Sokolov, Igor M.

    2016-01-01

    We extend the concept of accessibility in temporal networks to model infections with a finite infectious period such as the susceptible-infected-recovered (SIR) model. This approach is entirely based on elementary matrix operations and unifies the disease and network dynamics within one algebraic framework. We demonstrate the potential of this formalism for three examples of networks with high temporal resolution: networks of social contacts, sexual contacts, and livestock-trade. Our investigations provide a new methodological framework that can be used, for instance, to estimate the epidemic threshold, a quantity that determines disease parameters, for which a large-scale outbreak can be expected. PMID:27035128

  3. Three-dimensional visualization of temporal flow sequences

    NASA Astrophysics Data System (ADS)

    van Cruyningen, I.; Lozano, A.; Mungal, M. G.; Hanson, R. K.

    1991-03-01

    An account is given of a method for the generation of single three-dimensional views which accentuate the temporal correlations of temporally evolving two-dimensional data sets, thereby facilitating accurate interpretation. An improved volume-element-rendering algorithm is used to reduce data volumes on a PIXAR Image Computer; the algorithm operates on slices through the data volume, with the light source direction and observation direction initially selected. Attention is given to the illustrative case of a sequence of cinema frames of a forced jet.

  4. Phase Stable RF-over-fiber Transmission using Heterodyne Interferometry

    SciTech Connect

    Wilcox, R.; Byrd, J. M.; Doolittle, L.; Huang, G.; Staples, J. W.

    2010-01-02

    New scientific applications require phase-stabilized RF distribution to multiple remote locations. These include phased-array radio telescopes and short pulse free electron lasers. RF modulated onto a CW optical carrier and transmitted via fiber is capable of low noise, but commercially available systems aren't long term stable enough for these applications. Typical requirements are for less than 50fs long term temporal stability between receivers, which is 0.05 degrees at 3GHz. Good results have been demonstrated for RF distribution schemes based on transmission of short pulses, but these require specialized free-space optics and high stability mechanical infrastructure. We report a method which uses only standard telecom optical and RF components, and achieves less than 20fs RMS error over 300m of standard single-mode fiber. We demonstrate stable transmission of 3GHz over 300m of fiber with less than 0.017 degree (17fs) RMS phase error. An interferometer measures optical phase delay, providing information to a feed-forward correction of RF phase.

  5. Variance in saccadic eye movements reflects stable traits.

    PubMed

    Meyhöfer, Inga; Bertsch, Katja; Esser, Moritz; Ettinger, Ulrich

    2016-04-01

    Saccadic tasks are widely used to study cognitive processes, effects of pharmacological treatments, and mechanisms underlying psychiatric disorders. In genetic studies, it is assumed that saccadic endophenotypes are traits. While internal consistency and temporal stability of saccadic performance is high for most of the measures, the magnitude of underlying trait components has not been estimated, and influences of situational aspects and person by situation interactions have not been investigated. To do so, 68 healthy participants performed prosaccades, antisaccades, and memory-guided saccades on three occasions at weekly intervals at the same time of day. Latent state-trait modeling was applied to estimate the proportions of variance reflecting stable trait components, situational influences, and Person × Situation interaction effects. Mean variables for all saccadic tasks showed high to excellent reliabilities. Intraindividual standard deviations were found to be slightly less reliable. Importantly, an average of 60% of variance of a single measurement was explained by trans-situationally stable person effects, while situation aspects and interactions between person and situation were found to play a negligible role. We conclude that saccadic variables, in standard laboratory settings, represent highly reliable measures that are largely unaffected by situational influences. Extending previous reliability studies, these findings clearly demonstrate the trait-like nature of these measures and support their role as endophenotypes. © 2015 Society for Psychophysiological Research.

  6. 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...

  7. 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 ...

  8. Selective temporal attention enhances the temporal resolution of visual perception: Evidence from a temporal order judgment task.

    PubMed

    Correa, Angel; Sanabria, Daniel; Spence, Charles; Tudela, Pío; Lupiáñez, Juan

    2006-01-27

    We investigated whether attending to a particular point in time affects temporal resolution in a task in which participants judged which of two visual stimuli had been presented first. The results showed that temporal resolution can be improved by attending to the relevant moment as indicated by the temporal cue. This novel finding is discussed in terms of the differential effects of spatial and temporal attention on temporal resolution.

  9. Stable Defence. (Panel 7 on the Defence Applications of Operational Research, Research Study Group 18 on Stable Defence).

    DTIC Science & Technology

    1995-04-10

    criterion va is defined as va = and Van = Va fna cpri tcpr with cpre = attacker:defender combat power ratio at the end of the simulation rin; cpri ...combat power ratio at the end of the simulation run cpre must be at least tcpr times greater than the initial attacker:defender combat power ratio cpri

  10. 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.

  11. Detailed temporal structure of communication networks in groups of songbirds

    PubMed Central

    Clayton, David

    2016-01-01

    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. PMID:27335223

  12. Temporal and spectral deconvolution of data from diamond, photoconductive devices

    NASA Astrophysics Data System (ADS)

    Knauer, J. P.; Gindele, N. C.

    2004-10-01

    Diamond, photoconductive devices (DPCDs) have proven to be stable detectors of x-ray emission from plasmas. An array of six DPCDs is used on the OMEGA target chamber to measure the temporal and spectral dependence of x rays emitted from targets. 100 ps laser pulses incident on high-Z targets are used to measure the time response of the detectors, bias circuits, cables, and digitizer. This information is used to deconvolve the measured data to extract the temporal shape of the x-ray emission. The x-ray spectrum is measured by placing absorber filters for a specific x-ray energy region in front of the DPCDs. The data are analyzed with a linear algebraic method to determine the spectral shape. This technique removes the need to apply smoothing to the spectral analysis and provides "confidence bands" for the x-ray spectrum.

  13. 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

  14. Temporal Lobe Epilepsy in Children

    PubMed Central

    Nickels, Katherine C.; Wong-Kisiel, Lily C.; Moseley, Brian D.; Wirrell, Elaine C.

    2012-01-01

    The temporal lobe is a common focus for epilepsy. Temporal lobe epilepsy in infants and children differs from the relatively homogeneous syndrome seen in adults in several important clinical and pathological ways. Seizure semiology varies by age, and the ictal EEG pattern may be less clear cut than what is seen in adults. Additionally, the occurrence of intractable seizures in the developing brain may impact neurocognitive function remote from the temporal area. While many children will respond favorably to medical therapy, those with focal imaging abnormalities including cortical dysplasia, hippocampal sclerosis, or low-grade tumors are likely to be intractable. Expedient workup and surgical intervention in these medically intractable cases are needed to maximize long-term developmental outcome. PMID:22957247

  15. Temporal Partitioning on Multicore Platform

    NASA Astrophysics Data System (ADS)

    Mahmud Pathan, Ristat; Hashi, Feysal; Stenstrom, Per; Green, Lars-Goran; Hult, Torbjorn; Sandin, Patrik

    2014-08-01

    This paper addresses the problem of ensuring temporal partitioning according to the ARINC-653 standard for integrating multiple applications on the same multicore platform. To employ temporal partitioning, we propose the design and analysis of a hierarchical scheduling framework (HSF) for multicore platform. In HSF, each application has a server task, which is mapped to one of the physical cores of the multicore platform. The HSF framework is based on scheduling at two-levels: (i) a system-level scheduler for each core schedules the server tasks that are mapped to that core, and (ii) a task- level scheduler for each application schedules the tasks of the application. This paper presents the design and analysis of this two-level HSF that can be used to ensure temporal partitioning and meeting all the deadlines of each application tasks. The effectiveness of our technique is demonstrated using real-world space applications provided by RUAG Space Sweden AB.

  16. Contact process with temporal disorder.

    PubMed

    Barghathi, Hatem; Vojta, Thomas; Hoyos, José A

    2016-08-01

    We investigate the influence of time-varying environmental noise, i.e., temporal disorder, on the nonequilibrium phase transition of the contact process. Combining a real-time renormalization group, scaling theory, and large scale Monte-Carlo simulations in one and two dimensions, we show that the temporal disorder gives rise to an exotic critical point. At criticality, the effective noise amplitude diverges with increasing time scale, and the probability distribution of the density becomes infinitely broad, even on a logarithmic scale. Moreover, the average density and survival probability decay only logarithmically with time. This infinite-noise critical behavior can be understood as the temporal counterpart of infinite-randomness critical behavior in spatially disordered systems, but with exchanged roles of space and time. We also analyze the generality of our results, and we discuss potential experiments.

  17. Contact process with temporal disorder

    NASA Astrophysics Data System (ADS)

    Barghathi, Hatem; Vojta, Thomas; Hoyos, José A.

    2016-08-01

    We investigate the influence of time-varying environmental noise, i.e., temporal disorder, on the nonequilibrium phase transition of the contact process. Combining a real-time renormalization group, scaling theory, and large scale Monte-Carlo simulations in one and two dimensions, we show that the temporal disorder gives rise to an exotic critical point. At criticality, the effective noise amplitude diverges with increasing time scale, and the probability distribution of the density becomes infinitely broad, even on a logarithmic scale. Moreover, the average density and survival probability decay only logarithmically with time. This infinite-noise critical behavior can be understood as the temporal counterpart of infinite-randomness critical behavior in spatially disordered systems, but with exchanged roles of space and time. We also analyze the generality of our results, and we discuss potential experiments.

  18. Operating Systems.

    ERIC Educational Resources Information Center

    Denning, Peter J.; Brown, Robert L.

    1984-01-01

    A computer operating system spans multiple layers of complexity, from commands entered at a keyboard to the details of electronic switching. In addition, the system is organized as a hierarchy of abstractions. Various parts of such a system and system dynamics (using the Unix operating system as an example) are described. (JN)

  19. Operants1

    PubMed Central

    Schick, Karl

    1971-01-01

    The definition of an operant as a response class each of whose members possesses the property upon which reinforcement is contingent is not broad enough to cover the units that are supposed in Skinner's accounts of extinction, superstition, and transfer of learning. A broader definition is suggested. Finally, properties defining operants are discussed. PMID:16811526

  20. Operational Amplifiers.

    ERIC Educational Resources Information Center

    Foxcroft, G. E.

    1986-01-01

    Addresses the introduction of low cost equipment into high school and college physical science classes. Examines the properties of an "ideal" operational amplifier and discusses how it might be used under saturated and non-saturated conditions. Notes the action of a "real" operational amplifier. (TW)

  1. Payload Operations

    NASA Technical Reports Server (NTRS)

    Cissom, R. D.; Melton, T. L.; Schneider, M. P.; Lapenta, C. C.

    1999-01-01

    The objective of this paper is to provide the future ISS scientist and/or engineer a sense of what ISS payload operations are expected to be. This paper uses a real-time operations scenario to convey this message. The real-time operations scenario begins at the initiation of payload operations and runs through post run experiment analysis. In developing this scenario, it is assumed that the ISS payload operations flight and ground capabilities are fully available for use by the payload user community. Emphasis is placed on telescience operations whose main objective is to enable researchers to utilize experiment hardware onboard the International Space Station as if it were located in their terrestrial laboratory. An overview of the Payload Operations Integration Center (POIC) systems and user ground system options is included to provide an understanding of the systems and interfaces users will utilize to perform payload operations. Detailed information regarding POIC capabilities can be found in the POIC Capabilities Document, SSP 50304.

  2. Warehousing Operations.

    ERIC Educational Resources Information Center

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on warehousing operations is designed to provide instruction in the procedures used in warehousing operations. Introductory materials include specific information for MCI students and a study guide (guidelines to complete the course). The 22-hour…

  3. Operation REDWING

    DTIC Science & Technology

    1956-07-31

    only 16mm cinemascope films would be available after 1 August 1956t Act- tion was taken to modify the screens of the Terrace and Starlite theaters...approximately 900, was in operation throughout the interim and operational period. The Starlite Theater, which seats approximately 600, opened in

  4. Business & Operations

    ERIC Educational Resources Information Center

    Agron, Joe

    2007-01-01

    This article presents an interview with John D. Musso, executive director of the Association of School Business Officials (ASBO) International. Musso talks about trends and issues that will most affect school business and operations in 2007 and beyond. Despite the challenges facing school operations, he believes that the key to being successful at…

  5. Operational Amplifiers.

    ERIC Educational Resources Information Center

    Foxcroft, G. E.

    1986-01-01

    Addresses the introduction of low cost equipment into high school and college physical science classes. Examines the properties of an "ideal" operational amplifier and discusses how it might be used under saturated and non-saturated conditions. Notes the action of a "real" operational amplifier. (TW)

  6. Spatio-temporal generation regimes in quasi-CW Raman fiber lasers.

    PubMed

    Tarasov, Nikita; Sugavanam, Srikanth; Churkin, Dmitry

    2015-09-21

    We present experimental measurements of intensity spatio-temporal dynamics in quasi-CW Raman fiber laser. Depending on the power, the laser operates in different spatio-temporal regimes varying from partial mode-locking near the generation threshold to almost stochastic radiation and a generation of short-lived pulses at high power. The transitions between the generation regimes are evident in intensity spatio-temporal dynamics. Two-dimensional auto-correlation functions provide an additional insight into temporal and spatial properties of the observed regimes.

  7. 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

  8. Stable Isotopes of Ice: the Legacy of Willi Dansgaard

    NASA Astrophysics Data System (ADS)

    White, J. W. C.; Johnson, S. J.

    2012-04-01

    Stable isotope ratios of ice, D/H and 18O/16O are one of the key climate indicators measured in ice cores. These isotope ratios vary with temperature, a relationship based on physical principles backed up by many observations. The combination of these isotope ratios, expressed as the difference between the delta values with δ18O scaled by a factor of eight, is called the deuterium excess (d=δD-8*δ18O). This parameter varies primarily as a function of the conditions of evaporation of the parent moisture for snow, yielding a signal of ocean conditions measured in the ice. In his classic 1964 paper in Tellus, Willi Dansgaard laid out the theoretical and observational basis for using stable isotope ratios in ice cores as paleo-environmental tools. This paper, cited over 2,200 times, and written nearly 50 years ago, is one of the key foundational papers in paleoclimatology, and remains a must read for any student of stable isotope geochemistry. In this talk we will explore Dansgaard's legacy of ice core climatology, with a focus on his pioneering work in using the full temporal resolution of ice cores in Greenland to explore climate change on time scales of years to decades. While Dansgaard began his career applying a clever technique to a novel medium with the goal of simply trying to understand how our planet functions, he early on understood the power of ice cores to inform us about human impacts on the climate system, as well as the power of ice cores to tell us about natural climate variability on time scales of human interest and impact. Dansgaard's body of work is one of the solid pillars on which modern paleoclimatology stands, and continues to inform us today about modern anthropogenic climate change.

  9. [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

  10. Executing Temporal Networks With Uncertainty

    NASA Technical Reports Server (NTRS)

    Morris, Paul; Muscettola, Nicola

    2000-01-01

    Simple Temporal Networks (STNs) have proved useful in applications that involve metric time. However, many applications involve events whose timing is uncertain in the sense that it is not controlled by the execution agent. In this paper we consider execution algorithms for temporal networks with events of uncertain duration. We present two such algorithms. The first retains maximum flexibility, but requires potentially costly updates during execution. The second surrenders some flexibility in order to obtain a fast execution comparable to that available for ordinary STNs.

  11. High Gain and Frequency Ultra-Stable Integrators

    NASA Astrophysics Data System (ADS)

    Miller, K. E.; Ziemba, T. M.; Prager, J. R.; Lotz, D. E.

    2011-10-01

    Eagle Harbor Technologies has received DOE Phase I SBIR funding to continue the development of high gain and stability integrators that are capable of high bandwidth measurements over long pulse operation. The present design operates with a 10 us RC time, for pulse durations up to the second time scale, with a frequency response in excess of 10 MHz, and typical drift errors of under 10 mV. This integrator development effort consists of two primary tasks. The first is to demonstrate stable operation over the much longer time scales required by ITER. When a proper comparison between available integrator designs is made that normalizes for gain and operation time, the existing integrators are the best available and meet ITER requirements for stability. However, this stability needs to be demonstrated over the hour type time scales relevant to ITER, as opposed to the very high gain second type operation typically used within the ICC community. The second primary task is to incorporate the integrators into the National Instruments (NI) platform to allow for easy operation with modern DAQ systems.

  12. A Stable and Conservative Interface Treatment of Arbitrary Spatial Accuracy

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

    Stable and accurate interface conditions are derived for the linear advection-diffusion equation. The conditions are functionally independent of the spatial order of accuracy and rely only on the form of the discrete operator. We focus on high-order finite-difference operators that satisfy the summation-by-parts (SBP) property. We prove that stability is a natural consequence of the SBP operators used in conjunction with the new boundary conditions. In addition, we show that the interface treatments are conservative. New finite-difference operators of spatial accuracy up to sixth order are constructed: these operators satisfy the SBP property. Finite-difference operators are shown to admit design accuracy (p(sup th)-order global accuracy) when (p - 1)(sup th)-order stencil closures are used near the boundaries if the physical boundary conditions are implemented to at least p(sup th)-order accuracy. Stability and accuracy are demonstrated on the nonlinear Burgers' equation for an twelve-subdomain problem with randomly distributed interfaces.

  13. Stable Layers in the Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Mahalov, A.; Berman, N. S.; Fernando, H. J. S.; Yu, F.; Pardyjak, E.

    1998-11-01

    Field experimental studies on the establishment and growth of the nocturnal stable layer near the ground were made in January, 1998 using a tethered balloon at a site in Phoenix, Arizona. Days and nights with clear skies and light surface winds were of particular interest because small particle and carbon monoxide concentrations can be high during such times. Closest to the ground a shallow stable layer 20 meters deep with a buoyancy frequency (N) of 0.05 1/s rapidly developed before sundown. The height of this layer and N remained constant throughout the night. Above the 20-meter level, there was a transition layer which was also stable with N = 0.025 1/s. This transition layer grew throughout the night and reached 120 meters by dawn. Above the transition layer was a neutrally stable (residual) layer left over from the previous day. An unsteady layer 10 to 100 m thick with N = 0.025 1/s was also found at the top of the troposphere with the neutrally stable troposphere below and the stable stratosphere above. The growth and/or decay of turbulence in such stable layers will be discussed in light of recent theoretical developments.

  14. 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.

  15. 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.

  16. A System to Create Stable Nanoparticle Aerosols from Nanopowders

    PubMed Central

    Ding, Yaobo; Riediker, Michael

    2016-01-01

    Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring minimal amounts of test materials (min. 200 mg), for studying powder aerosolization behavior and aerosol properties. The aerosolization procedure follows the concept of the fluidized-bed process, but occurs in the modified volume of a V-shaped aerosol generator. The airborne particle number concentration is adjustable by controlling the air flow rate. The system supplied stable aerosol generation rates and particle size distributions over long periods (0.5-2 hr and possibly longer), which are important, for example, to study aerosol behavior, but also for toxicological studies. Strict adherence to the operating procedures during the aerosolization experiments ensures the generation of reproducible test results. The critical steps in the standard protocol are the preparation of the material and setup, and the aerosolization operations themselves. The system can be used for experiments requiring stable aerosol concentrations and may also be an alternative method for testing dustiness. The controlled aerosolization made possible with this setup occurs using energy inputs (may be characterized by aerosolization air velocity) that are within the ranges commonly found in occupational environments where nanomaterial powders are handled. This setup and its operating protocol are thus helpful for human exposure and risk assessment. PMID:27501179

  17. Reduced temporal integration in Belgian Waterslager canaries

    NASA Astrophysics Data System (ADS)

    Lauer, Amanda M.; Dooling, Robert J.

    2004-05-01

    Belgian Waterslager canaries (BWS) are bred for their low-frequency song and have been shown to have hair cell abnormalities in the inner ear that result in elevated thresholds at higher frequencies. Previous results show that resolution of temporal fine structure, or the ability to resolve rapidly occurring changes in complex sounds, is enhanced in BWS canaries. In a continuing effort to assess the effects of the BWS inner ear pathology on hearing, we here investigate the ability to integrate acoustic information over longer periods of time. Absolute thresholds for 1.0-, 2.0-, and 4.0-kHz pure tones were measured in BWS and normal-hearing nonBWS canary strains for durations ranging from 5 to 480 ms using operant conditioning methods. NonBWS canaries showed a decrease in threshold of approximately 10-15 dB with increasing tone duration for all frequencies. In contrast, BWS showed almost no change in threshold across the range of durations tested for all frequencies. The reduced temporal integration in BWS canaries with hair cell abnormalities parallels similar findings in humans with cochlear damage. [Work supported by NIH DC01372 to RJD and DC05450 to AML.

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

    PubMed Central

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

    2012-01-01

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

  19. Bi-stable optical element actuator device

    DOEpatents

    Holdener, Fred R.; Boyd, Robert D.

    2002-01-01

    The present invention is a bistable optical element actuator device utilizing a powered means to move an actuation arm, to which an optical element is attached, between two stable positions. A non-powered means holds the actuation arm in either of the two stable positions. The optical element may be a electromagnetic (EM) radiation or particle source, an instrument, or EM radiation or particle transmissive reflective or absorptive elements. A bearing is used to transfer motion and smoothly transition the actuation arm between the two stable positions.

  20. Spatial and temporal complexities of reproductive behavior and sex ratios: a case from parasitic insects.

    PubMed

    Dittmar, Katharina; Morse, Solon; Gruwell, Matthew; Mayberry, Jason; DiBlasi, Emily

    2011-05-10

    Sex ratios are important empirical data in predicting sex allocation strategy and selection in populations. Therefore, they should be sampled at crucial developmental steps before and after parental investment. In parasites with free-living (off-host) developmental stages the timing and method of sampling is not trivial, because ecological niches are frequently poorly known. Consequently, information is scarce for sex ratios of these parasites between conception and sexual maturity. Often, only data from adult parasites are available, which usually were collected from the parasite's hosts. Generally, these ratios are assumed to represent operational sex ratios. We here report three years of empirical data on population sex differentials from a bat ectoparasite (Trichobius frequens) with off-host developmental stages. At emergence these parasites exhibit a significant and seasonally stable female biased sex ratio. This bias is lost in the adult population on the roosting host, which shows sex ratios at equality. This is best explained by a behaviorally driven, sex-dependent mortality differential. Because consistently only subsets of females are available to mate, the operational sex ratio in the population is likely male biased. Host capture experiments throughout the day show a statistically significant, but temporary male excess in bat flies on foraging bats. This phenomenon is partly driven by the diurnal rhythms of female larviposition, and partly due to parasites remaining in the bat roost during foraging. Because most previous research in bat flies is based only on foraging bats, female contributions to physical sex ratios have been underestimated. Our results highlight the importance of detailed natural history observations, and emphasize that ignoring the spatial and temporal heterogeneity of reproduction in any organism will lead to significant empirical sampling errors of sex ratios, and may obscure operational sex ratios.