Breaking the Social Contract. The Fiscal Crisis in Higher Education.

ERIC Educational Resources Information Center

Council for Aid to Education, Santa Monica, CA.

This report presents the results of a 2-year study of the fiscal condition of higher education in the United States. The study found that at a time when the level of education needed for productive employment is increasing, college costs and demand are rising much faster than funding. Unless sweeping changes are made to control costs, millions of…

Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET.

PubMed

Gundacker, Stefan; Auffray, Etiennette; Pauwels, Kristof; Lecoq, Paul

2016-04-07

The coincidence time resolution (CTR) of scintillator based detectors commonly used in positron emission tomography is well known to be dependent on the scintillation decay time (τd) and the number of photons detected (n'), i.e. CTR proportional variant √τd/n'. However, it is still an open question to what extent the scintillation rise time (τr) and other fast or prompt photons, e.g. Cherenkov photons, at the beginning of the scintillation process influence the CTR. This paper presents measurements of the scintillation emission rate for different LSO type crystals, i.e. LSO:Ce, LYSO:Ce, LSO:Ce codoped Ca and LGSO:Ce. For the various LSO-type samples measured we find an average value of 70 ps for the scintillation rise time, although some crystals like LSO:Ce codoped Ca seem to have a much faster rise time in the order of 20 ps. Additional measurements for LuAG:Ce and LuAG:Pr show a rise time of 535 ps and 251 ps, respectively. For these crystals, prompt photons (Cherenkov) can be observed at the beginning of the scintillation event. Furthermore a significantly lower rise time value is observed when codoping with calcium. To quantitatively investigate the influence of the rise time to the time resolution we measured the CTR with the same L(Y)SO samples and compared the values to Monte Carlo simulations. Using the measured relative light yields, rise- and decay times of the scintillators we are able to quantitatively understand the measured CTRs in our simulations. Although the rise time is important to fully explain the CTR variation for the different samples tested we determined its influence on the CTR to be in the order of a few percent only. This result is surprising because, if only photonstatistics of the scintillation process is considered, the CTR would be proportional to the square root of the rise time. The unexpected small rise time influence on the CTR can be explained by the convolution of the scintillation rate with the single photon time resolution (SPTR) of the photodetector and the photon travel spread (PTS) in the crystal. The timing benefits of prompt photons at the beginning of the scintillation process (Cherenkov etc) are further studied, which leads to the conclusion that the scintillation rise time, SPTR and PTS have to be lowered simultaneously to fully profit from these fast photons in order to improve the CTR significantly.

Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET

NASA Astrophysics Data System (ADS)

Gundacker, Stefan; Auffray, Etiennette; Pauwels, Kristof; Lecoq, Paul

2016-04-01

The coincidence time resolution (CTR) of scintillator based detectors commonly used in positron emission tomography is well known to be dependent on the scintillation decay time ({τd} ) and the number of photons detected ({{n}\\prime} ), i.e. CTR\\propto \\sqrt{{τd}/{{n}\\prime}} . However, it is still an open question to what extent the scintillation rise time ({τr} ) and other fast or prompt photons, e.g. Cherenkov photons, at the beginning of the scintillation process influence the CTR. This paper presents measurements of the scintillation emission rate for different LSO type crystals, i.e. LSO:Ce, LYSO:Ce, LSO:Ce codoped Ca and LGSO:Ce. For the various LSO-type samples measured we find an average value of 70 ps for the scintillation rise time, although some crystals like LSO:Ce codoped Ca seem to have a much faster rise time in the order of 20 ps. Additional measurements for LuAG:Ce and LuAG:Pr show a rise time of 535 ps and 251 ps, respectively. For these crystals, prompt photons (Cherenkov) can be observed at the beginning of the scintillation event. Furthermore a significantly lower rise time value is observed when codoping with calcium. To quantitatively investigate the influence of the rise time to the time resolution we measured the CTR with the same L(Y)SO samples and compared the values to Monte Carlo simulations. Using the measured relative light yields, rise- and decay times of the scintillators we are able to quantitatively understand the measured CTRs in our simulations. Although the rise time is important to fully explain the CTR variation for the different samples tested we determined its influence on the CTR to be in the order of a few percent only. This result is surprising because, if only photonstatistics of the scintillation process is considered, the CTR would be proportional to the square root of the rise time. The unexpected small rise time influence on the CTR can be explained by the convolution of the scintillation rate with the single photon time resolution (SPTR) of the photodetector and the photon travel spread (PTS) in the crystal. The timing benefits of prompt photons at the beginning of the scintillation process (Cherenkov etc) are further studied, which leads to the conclusion that the scintillation rise time, SPTR and PTS have to be lowered simultaneously to fully profit from these fast photons in order to improve the CTR significantly.

Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling [Kinematics and dynamics of the East Pacific Rise linked to whole mantel convective motions

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

Rowley, David B.; Forte, Alessandro M.; Rowan, Christopher J.

Earth’s tectonic plates are generally considered to be driven largely by negative buoyancy associated with subduction of oceanic lithosphere. In this context, mid-ocean ridges (MORs) are passive plate boundaries whose divergence accommodates flow driven by subduction of oceanic slabs at trenches. We show that over the past 80 million years (My), the East Pacific Rise (EPR), Earth’s dominant MOR, has been characterized by limited ridge-perpendicular migration and persistent, asymmetric ridge accretion that are anomalous relative to other MORs. We reconstruct the subduction-related buoyancy fluxes of plates on either side of the EPR. The general expectation is that greater slab pullmore » should correlate with faster plate motion and faster spreading at the EPR. Moreover, asymmetry in slab pull on either side of the EPR should correlate with either ridge migration or enhanced plate velocity in the direction of greater slab pull. Based on our analysis, none of the expected correlations are evident. This implies that other forces significantly contribute to EPR behavior. We explain these observations using mantle flow calculations based on globally integrated buoyancy distributions that require core-mantle boundary heat flux of up to 20 TW. The time-dependent mantle flow predictions yield a long-lived deep-seated upwelling that has its highest radial velocity under the EPR and is inferred to control its observed kinematics. Lastly, the mantle-wide upwelling beneath the EPR drives horizontal components of asthenospheric flows beneath the plates that are similarly asymmetric but faster than the overlying surface plates, thereby contributing to plate motions through viscous tractions in the Pacific region.« less

Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling [Kinematics and dynamics of the East Pacific Rise linked to whole mantel convective motions

DOE PAGES

Rowley, David B.; Forte, Alessandro M.; Rowan, Christopher J.; ...

2016-12-23

Earth’s tectonic plates are generally considered to be driven largely by negative buoyancy associated with subduction of oceanic lithosphere. In this context, mid-ocean ridges (MORs) are passive plate boundaries whose divergence accommodates flow driven by subduction of oceanic slabs at trenches. We show that over the past 80 million years (My), the East Pacific Rise (EPR), Earth’s dominant MOR, has been characterized by limited ridge-perpendicular migration and persistent, asymmetric ridge accretion that are anomalous relative to other MORs. We reconstruct the subduction-related buoyancy fluxes of plates on either side of the EPR. The general expectation is that greater slab pullmore » should correlate with faster plate motion and faster spreading at the EPR. Moreover, asymmetry in slab pull on either side of the EPR should correlate with either ridge migration or enhanced plate velocity in the direction of greater slab pull. Based on our analysis, none of the expected correlations are evident. This implies that other forces significantly contribute to EPR behavior. We explain these observations using mantle flow calculations based on globally integrated buoyancy distributions that require core-mantle boundary heat flux of up to 20 TW. The time-dependent mantle flow predictions yield a long-lived deep-seated upwelling that has its highest radial velocity under the EPR and is inferred to control its observed kinematics. Lastly, the mantle-wide upwelling beneath the EPR drives horizontal components of asthenospheric flows beneath the plates that are similarly asymmetric but faster than the overlying surface plates, thereby contributing to plate motions through viscous tractions in the Pacific region.« less

Men's Increase in College Enrollment Breaks Long-Term Trend--Rises Faster than Rate for Women. Fact Book Bulletin

ERIC Educational Resources Information Center

Southern Regional Education Board (SREB), 2012

2012-01-01

From 2005 to 2010, in an historic turnaround, the number of men enrolled in college increased faster than the number of women in the Southern Regional Education Board (SREB) region, the West and the Northeast. The Midwest was the only region where enrollment by women increased faster than for men over this period. In the SREB region, men's…

The fermionic projector in a time-dependent external potential: Mass oscillation property and Hadamard states

NASA Astrophysics Data System (ADS)

Finster, Felix; Murro, Simone; Röken, Christian

2016-07-01

We give a non-perturbative construction of the fermionic projector in Minkowski space coupled to a time-dependent external potential which is smooth and decays faster than quadratically for large times. The weak and strong mass oscillation properties are proven. We show that the integral kernel of the fermionic projector is of the Hadamard form, provided that the time integral of the spatial sup-norm of the potential satisfies a suitable bound. This gives rise to an algebraic quantum field theory of Dirac fields in an external potential with a distinguished pure quasi-free Hadamard state.

Probing the neutrino mass hierarchy with the rise time of a supernova burst

NASA Astrophysics Data System (ADS)

Serpico, Pasquale D.; Chakraborty, Sovan; Fischer, Tobias; Hüdepohl, Lorenz; Janka, Hans-Thomas; Mirizzi, Alessandro

2012-04-01

The rise time of a Galactic supernova (SN) ν¯e light curve, observable at a high-statistics experiment such as the Icecube Cherenkov detector, can provide a diagnostic tool for the neutrino mass hierarchy at “large” 1-3 leptonic mixing angle ϑ13. Thanks to the combination of matter suppression of collective effects at early post-bounce times on one hand and the presence of the ordinary Mikheyev-Smirnov-Wolfenstein effect in the outer layers of the SN on the other hand, a sufficiently fast rise time on O(100)ms scale is indicative of an inverted mass hierarchy. We investigate results from an extensive set of stellar core-collapse simulations, providing a first exploration of the astrophysical robustness of these features. We find that for all the models analyzed (sharing the same weak interaction microphysics) the rise times for the same hierarchy are similar not only qualitatively, but also quantitatively, with the signals for the two classes of hierarchies significantly separated. We show via Monte Carlo simulations that the two cases should be distinguishable at IceCube for SNe at a typical Galactic distance 99% of the time. Finally, a preliminary survey seems to show that the faster rise time for inverted hierarchy as compared to normal hierarchy is a qualitatively robust feature predicted by several simulation groups. Since the viability of this signature ultimately depends on the quantitative assessment of theoretical/numerical uncertainties, our results motivate an extensive campaign of comparison of different code predictions at early accretion times with implementation of microphysics of comparable sophistication, including effects such as nucleon recoils in weak interactions.

Time-resolved coherent Raman spectroscopy by high-speed pump-probe delay scanning.

PubMed

Domingue, S R; Winters, D G; Bartels, R A

2014-07-15

Using a spinning window pump-probe delay scanner, we demonstrate a means of acquiring time-resolved vibrational spectra at rates up to 700 Hz. The time-dependent phase shift accumulated by the probe pulse in the presence of a coherently vibrating sample gives rise to a Raman-induced frequency shifting readily detectable in a balanced detector. This rapid delay scanning system represents a 23-fold increase in averaging speed and is >10× faster than state-of-the-art voice coil delay lines. These advancements make pump-probe spectroscopy a more practical means of imaging complex media.

Reaction temperature sensing (RTS)-based control for Li-ion battery safety

PubMed Central

Zhang, Guangsheng; Cao, Lei; Ge, Shanhai; Wang, Chao-Yang; Shaffer, Christian E.; Rahn, Christopher D.

2015-01-01

We report reaction temperature sensing (RTS)-based control to fundamentally enhance Li-ion battery safety. RTS placed at the electrochemical interface inside a Li-ion cell is shown to detect temperature rise much faster and more accurately than external measurement of cell surface temperature. We demonstrate, for the first time, that RTS-based control shuts down a dangerous short-circuit event 3 times earlier than surface temperature- based control and prevents cell overheating by 50 °C and the resultant cell damage. PMID:26658957

Evidence for sub-Chandrasekhar-mass progenitors of Type Ia supernovae at the faint end of the width-luminosity relation

NASA Astrophysics Data System (ADS)

Blondin, Stéphane; Dessart, Luc; Hillier, D. John; Khokhlov, Alexei M.

2017-09-01

The faster light-curve evolution of low-luminosity Type Ia supernovae (SNe Ia) suggests that they could result from the explosion of white dwarf (WD) progenitors below the Chandrasekhar mass (MCh). Here we present 1D non-local thermodynamic equilibrium time-dependent radiative transfer simulations of pure central detonations of carbon-oxygen WDs with a mass (Mtot) between 0.88 and 1.15 M⊙ and a 56Ni yield between 0.08 and 0.84 M⊙. Their lower ejecta density compared to MCh models results in a more rapid increase of the luminosity at early times and an enhanced γ-ray escape fraction past maximum light. Consequently, their bolometric light curves display shorter rise times and larger post-maximum decline rates. Moreover, the higher M(56Ni)/Mtot ratio at a given 56Ni mass enhances the temperature and ionization level in the spectrum-formation region for the less luminous models, giving rise to bluer colours at maximum light and a faster post-maximum evolution of the B - V colour. For sub-MCh models fainter than MB ≈ -18.5 mag at peak, the greater bolometric decline and faster colour evolution lead to a larger B-band post-maximum decline rate, ΔM15(B). In particular, all of our previously published MCh models (standard and pulsational delayed detonations) are confined to ΔM15(B) < 1.4 mag, while the sub-MCh models with Mtot ≲ 1 M⊙ extend beyond this limit to ΔM15(B) ≈ 1.65 mag for a peak MB ≈ -17 mag, in better agreement with the observed width-luminosity relation (WLR). Regardless of the precise ignition mechanism, these simulations suggest that fast-declining SNe Ia at the faint end of the WLR could result from the explosion of WDs whose mass is significantly below the Chandrasekhar limit.

Trends in summer bottom-water temperatures on the northern Gulf of Mexico continental shelf from 1985 to 2015.

PubMed

Turner, R Eugene; Rabalais, Nancy N; Justić, Dubravko

2017-01-01

We quantified trends in the 1985 to 2015 summer bottom-water temperature on the northern Gulf of Mexico (nGOM) continental shelf for data collected at 88 stations with depths ranging from 3 to 63 m. The analysis was supplemented with monthly data collected from 1963 to 1965 in the same area. The seasonal summer peak in average bottom-water temperature varied concurrently with air temperature, but with a 2- to 5-month lag. The summer bottom-water temperature declined gradually with depth from 30 oC at stations closest to the shore, to 20 oC at the offshore edge of the study area, and increased an average 0.051 oC y-1 between1963 and 2015. The bottom-water warming in summer for all stations was 1.9 times faster compared to the rise in local summer air temperatures, and 6.4 times faster than the concurrent increase in annual global ocean sea surface temperatures. The annual rise in average summer bottom-water temperatures on the subtropical nGOM continental shelf is comparable to the few published temperature trend estimates from colder environments. These recent changes in the heat storage on the nGOM continental shelf will affect oxygen and carbon cycling, spatial distribution of fish and shrimp, and overall species diversity.

The effect of fast and slow motor unit activation on whole-muscle mechanical performance: the size principle may not pose a mechanical paradox

PubMed Central

Holt, N. C.; Wakeling, J. M.; Biewener, A. A.

2014-01-01

The output of skeletal muscle can be varied by selectively recruiting different motor units. However, our knowledge of muscle function is largely derived from muscle in which all motor units are activated. This discrepancy may limit our understanding of in vivo muscle function. Hence, this study aimed to characterize the mechanical properties of muscle with different motor unit activation. We determined the isometric properties and isotonic force–velocity relationship of rat plantaris muscles in situ with all of the muscle active, 30% of the muscle containing predominately slower motor units active or 20% of the muscle containing predominately faster motor units active. There was a significant effect of active motor unit type on isometric force rise time (p < 0.001) and the force–velocity relationship (p < 0.001). Surprisingly, force rise time was longer and maximum shortening velocity higher when all motor units were active than when either fast or slow motor units were selectively activated. We propose this is due to the greater relative effects of factors such as series compliance and muscle resistance to shortening during sub-maximal contractions. The findings presented here suggest that recruitment according to the size principle, where slow motor units are activated first and faster ones recruited as demand increases, may not pose a mechanical paradox, as has been previously suggested. PMID:24695429

The effect of fast and slow motor unit activation on whole-muscle mechanical performance: the size principle may not pose a mechanical paradox.

PubMed

Holt, N C; Wakeling, J M; Biewener, A A

2014-05-22

The output of skeletal muscle can be varied by selectively recruiting different motor units. However, our knowledge of muscle function is largely derived from muscle in which all motor units are activated. This discrepancy may limit our understanding of in vivo muscle function. Hence, this study aimed to characterize the mechanical properties of muscle with different motor unit activation. We determined the isometric properties and isotonic force-velocity relationship of rat plantaris muscles in situ with all of the muscle active, 30% of the muscle containing predominately slower motor units active or 20% of the muscle containing predominately faster motor units active. There was a significant effect of active motor unit type on isometric force rise time (p < 0.001) and the force-velocity relationship (p < 0.001). Surprisingly, force rise time was longer and maximum shortening velocity higher when all motor units were active than when either fast or slow motor units were selectively activated. We propose this is due to the greater relative effects of factors such as series compliance and muscle resistance to shortening during sub-maximal contractions. The findings presented here suggest that recruitment according to the size principle, where slow motor units are activated first and faster ones recruited as demand increases, may not pose a mechanical paradox, as has been previously suggested.

Explaining Cold-Pulse Dynamics in Tokamak Plasmas Using Local Turbulent Transport Models

NASA Astrophysics Data System (ADS)

Rodriguez-Fernandez, P.; White, A. E.; Howard, N. T.; Grierson, B. A.; Staebler, G. M.; Rice, J. E.; Yuan, X.; Cao, N. M.; Creely, A. J.; Greenwald, M. J.; Hubbard, A. E.; Hughes, J. W.; Irby, J. H.; Sciortino, F.

2018-02-01

A long-standing enigma in plasma transport has been resolved by modeling of cold-pulse experiments conducted on the Alcator C-Mod tokamak. Controlled edge cooling of fusion plasmas triggers core electron heating on time scales faster than an energy confinement time, which has long been interpreted as strong evidence of nonlocal transport. This Letter shows that the steady-state profiles, the cold-pulse rise time, and disappearance at higher density as measured in these experiments are successfully captured by a recent local quasilinear turbulent transport model, demonstrating that the existence of nonlocal transport phenomena is not necessary for explaining the behavior and time scales of cold-pulse experiments in tokamak plasmas.

Efficient carrier relaxation and fast carrier recombination of N-polar InGaN/GaN light emitting diodes

NASA Astrophysics Data System (ADS)

Feng, Shih-Wei; Liao, Po-Hsun; Leung, Benjamin; Han, Jung; Yang, Fann-Wei; Wang, Hsiang-Chen

2015-07-01

Based on quantum efficiency and time-resolved electroluminescence measurements, the effects of carrier localization and quantum-confined Stark effect (QCSE) on carrier transport and recombination dynamics of Ga- and N-polar InGaN/GaN light-emitting diodes (LEDs) are reported. The N-polar LED exhibits shorter ns-scale response, rising, delay, and recombination times than the Ga-polar one does. Stronger carrier localization and the combined effects of suppressed QCSE and electric field and lower potential barrier acting upon the forward bias in an N-polar LED provide the advantages of more efficient carrier relaxation and faster carrier recombination. By optimizing growth conditions to enhance the radiative recombination, the advantages of more efficient carrier relaxation and faster carrier recombination in a competitive performance N-polar LED can be realized for applications of high-speed flash LEDs. The research results provide important information for carrier transport and recombination dynamics of an N-polar InGaN/GaN LED.

Efficient carrier relaxation and fast carrier recombination of N-polar InGaN/GaN light emitting diodes

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

Feng, Shih-Wei, E-mail: swfeng@nuk.edu.tw; Liao, Po-Hsun; Leung, Benjamin

2015-07-28

Based on quantum efficiency and time-resolved electroluminescence measurements, the effects of carrier localization and quantum-confined Stark effect (QCSE) on carrier transport and recombination dynamics of Ga- and N-polar InGaN/GaN light-emitting diodes (LEDs) are reported. The N-polar LED exhibits shorter ns-scale response, rising, delay, and recombination times than the Ga-polar one does. Stronger carrier localization and the combined effects of suppressed QCSE and electric field and lower potential barrier acting upon the forward bias in an N-polar LED provide the advantages of more efficient carrier relaxation and faster carrier recombination. By optimizing growth conditions to enhance the radiative recombination, the advantagesmore » of more efficient carrier relaxation and faster carrier recombination in a competitive performance N-polar LED can be realized for applications of high-speed flash LEDs. The research results provide important information for carrier transport and recombination dynamics of an N-polar InGaN/GaN LED.« less

Type II supernova energetics and comparison of light curves to shock-cooling models

DOE PAGES

Rubin, Adam; Gal-Yam, Avishay; De Cia, Annalisa; ...

2016-03-16

During the first few days after explosion, Type II supernovae (SNe) are dominated by relatively simple physics. Theoretical predictions regarding early-time SN light curves in the ultraviolet (UV) and optical bands are thus quite robust. We present, for the first time, a sample of 57 R-band SN II light curves that are well-monitored during their rise, withmore » $$\\gt 5$$ detections during the first 10 days after discovery, and a well-constrained time of explosion to within 1–3 days. We show that the energy per unit mass (E/M) can be deduced to roughly a factor of five by comparing early-time optical data to the 2011 model of Rabinak & Waxman, while the progenitor radius cannot be determined based on R-band data alone. We find that SN II explosion energies span a range of E/M = (0.2–20) × 10 51 erg/(10 $${M}_{\\odot }$$), and have a mean energy per unit mass of $$\\langle E/M\\rangle =0.85\\times {10}^{51}$$ erg/(10 $${M}_{\\odot }$$), corrected for Malmquist bias. Assuming a small spread in progenitor masses, this indicates a large intrinsic diversity in explosion energy. Moreover, E/M is positively correlated with the amount of 56Ni produced in the explosion, as predicted by some recent models of core-collapse SNe. We further present several empirical correlations. The peak magnitude is correlated with the decline rate ($${\\rm{\\Delta }}{m}_{15}$$), the decline rate is weakly correlated with the rise time, and the rise time is not significantly correlated with the peak magnitude. Faster declining SNe are more luminous and have longer rise times. Lastly, this limits the possible power sources for such events.« less

Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling

PubMed Central

Rowley, David B.; Forte, Alessandro M.; Rowan, Christopher J.; Glišović, Petar; Moucha, Robert; Grand, Stephen P.; Simmons, Nathan A.

2016-01-01

Earth’s tectonic plates are generally considered to be driven largely by negative buoyancy associated with subduction of oceanic lithosphere. In this context, mid-ocean ridges (MORs) are passive plate boundaries whose divergence accommodates flow driven by subduction of oceanic slabs at trenches. We show that over the past 80 million years (My), the East Pacific Rise (EPR), Earth’s dominant MOR, has been characterized by limited ridge-perpendicular migration and persistent, asymmetric ridge accretion that are anomalous relative to other MORs. We reconstruct the subduction-related buoyancy fluxes of plates on either side of the EPR. The general expectation is that greater slab pull should correlate with faster plate motion and faster spreading at the EPR. Moreover, asymmetry in slab pull on either side of the EPR should correlate with either ridge migration or enhanced plate velocity in the direction of greater slab pull. Based on our analysis, none of the expected correlations are evident. This implies that other forces significantly contribute to EPR behavior. We explain these observations using mantle flow calculations based on globally integrated buoyancy distributions that require core-mantle boundary heat flux of up to 20 TW. The time-dependent mantle flow predictions yield a long-lived deep-seated upwelling that has its highest radial velocity under the EPR and is inferred to control its observed kinematics. The mantle-wide upwelling beneath the EPR drives horizontal components of asthenospheric flows beneath the plates that are similarly asymmetric but faster than the overlying surface plates, thereby contributing to plate motions through viscous tractions in the Pacific region. PMID:28028535

Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling.

PubMed

Rowley, David B; Forte, Alessandro M; Rowan, Christopher J; Glišović, Petar; Moucha, Robert; Grand, Stephen P; Simmons, Nathan A

2016-12-01

Earth's tectonic plates are generally considered to be driven largely by negative buoyancy associated with subduction of oceanic lithosphere. In this context, mid-ocean ridges (MORs) are passive plate boundaries whose divergence accommodates flow driven by subduction of oceanic slabs at trenches. We show that over the past 80 million years (My), the East Pacific Rise (EPR), Earth's dominant MOR, has been characterized by limited ridge-perpendicular migration and persistent, asymmetric ridge accretion that are anomalous relative to other MORs. We reconstruct the subduction-related buoyancy fluxes of plates on either side of the EPR. The general expectation is that greater slab pull should correlate with faster plate motion and faster spreading at the EPR. Moreover, asymmetry in slab pull on either side of the EPR should correlate with either ridge migration or enhanced plate velocity in the direction of greater slab pull. Based on our analysis, none of the expected correlations are evident. This implies that other forces significantly contribute to EPR behavior. We explain these observations using mantle flow calculations based on globally integrated buoyancy distributions that require core-mantle boundary heat flux of up to 20 TW. The time-dependent mantle flow predictions yield a long-lived deep-seated upwelling that has its highest radial velocity under the EPR and is inferred to control its observed kinematics. The mantle-wide upwelling beneath the EPR drives horizontal components of asthenospheric flows beneath the plates that are similarly asymmetric but faster than the overlying surface plates, thereby contributing to plate motions through viscous tractions in the Pacific region.

Distinct Effect of Impact Rise Times on Immediate and Early Neuropathology After Brain Injury in Juvenile Rats

PubMed Central

Jayakumar, Archana; Pfister, Bryan J.; Santhakumar, Vijayalakshmi

2015-01-01

Traumatic brain injury (TBI) can occur from physical trauma from a wide spectrum of insults ranging from explosions to falls. The biomechanics of the trauma can vary in key features, including the rate and magnitude of the insult. Although the effect of peak injury pressure on neurological outcome has been examined in the fluid percussion injury (FPI) model, it is unknown whether differences in rate of rise of the injury waveform modify cellular and physiological changes after TBI. Using a programmable FPI device, we examined juvenile rats subjected to a constant peak pressure at two rates of injury: a standard FPI rate of rise and a faster rate of rise to the same peak pressure. Immediate postinjury assessment identified fewer seizures and relatively brief loss of consciousness after fast-rise injuries than after standard-rise injuries at similar peak pressures. Compared with rats injured at standard rise, fewer silver-stained injured neuronal profiles and degenerating hilar neurons were observed 4-6 hr after fast-rise FPI. However, 1 week postinjury, both fast- and standard-rise FPI resulted in hilar cell loss and enhanced perforant path-evoked granule cell field excitability compared with sham controls. Notably, the extent of neuronal loss and increase in dentate excitability were not different between rats injured at fast and standard rates of rise to peak pressure. Our data indicate that reduced cellular damage and improved immediate neurological outcome after fast rising primary concussive injuries mask the severity of the subsequent cellular and neurophysiological pathology and may be unreliable as a predictor of prognosis. PMID:24799156

Demonstration of a scalable frequency-domain readout of metallic magnetic calorimeters by means of a microwave SQUID multiplexer

NASA Astrophysics Data System (ADS)

Kempf, Sebastian; Wegner, Mathias; Fleischmann, Andreas; Gastaldo, Loredana; Herrmann, Felix; Papst, Maximilian; Richter, Daniel; Enss, Christian

2017-01-01

We report on the first demonstration of a scalable GHz frequency-domain readout of metallic magnetic calorimeters (MMCs) using a 64 pixel detector array that is read out by an integrated, on-chip microwave SQUID multiplexer. The detector array is optimized for detecting soft X-ray photons and the multiplexer is designed to provide a signal rise time τrise<400 ns and an intrinsic energy sensitivity ɛ <30 h . This results in an expected energy resolution Δ EFWHM <10 eV . We measured a signal rise time τrise as low as 90 ns and an energy resolution Δ EFWHM as low as 50 eV for 5.9 keV photons. The rise time is about an order of magnitude faster compared to other multiplexed low-temperature microcalorimeters and close to the intrinsic value set by the coupling between electron and spins. The energy resolution is degraded with respect to our design value due to a rather low intrinsic quality factor of the microwave resonators that is caused by the quality of the Josephson junction of the associated rf-SQUID as well as an elevated chip temperature as compared to the heat bath. Though the achieved energy resolution is not yet compatible with state-of-the-art single-channel MMCs, this demonstration of a scalable readout approach for MMCs in combination with the full understanding of the device performance showing ways how to improve represents an important milestone for the development of future large-scale MMC detector arrays.

Capillary Rise: Validity of the Dynamic Contact Angle Models.

PubMed

Wu, Pingkeng; Nikolov, Alex D; Wasan, Darsh T

2017-08-15

The classical Lucas-Washburn-Rideal (LWR) equation, using the equilibrium contact angle, predicts a faster capillary rise process than experiments in many cases. The major contributor to the faster prediction is believed to be the velocity dependent dynamic contact angle. In this work, we investigated the dynamic contact angle models for their ability to correct the dynamic contact angle effect in the capillary rise process. We conducted capillary rise experiments of various wetting liquids in borosilicate glass capillaries and compared the model predictions with our experimental data. The results show that the LWR equations modified by the molecular kinetic theory and hydrodynamic model provide good predictions on the capillary rise of all the testing liquids with fitting parameters, while the one modified by Joos' empirical equation works for specific liquids, such as silicone oils. The LWR equation modified by molecular self-layering model predicts well the capillary rise of carbon tetrachloride, octamethylcyclotetrasiloxane, and n-alkanes with the molecular diameter or measured solvation force data. The molecular self-layering model modified LWR equation also has good predictions on the capillary rise of silicone oils covering a wide range of bulk viscosities with the same key parameter W(0), which results from the molecular self-layering. The advantage of the molecular self-layering model over the other models reveals the importance of the layered molecularly thin wetting film ahead of the main meniscus in the energy dissipation associated with dynamic contact angle. The analysis of the capillary rise of silicone oils with a wide range of bulk viscosities provides new insights into the capillary dynamics of polymer melts.

Type II Supernova Energetics and Comparison of Light Curves to Shock-cooling Models

NASA Astrophysics Data System (ADS)

Rubin, Adam; Gal-Yam, Avishay; De Cia, Annalisa; Horesh, Assaf; Khazov, Danny; Ofek, Eran O.; Kulkarni, S. R.; Arcavi, Iair; Manulis, Ilan; Yaron, Ofer; Vreeswijk, Paul; Kasliwal, Mansi M.; Ben-Ami, Sagi; Perley, Daniel A.; Cao, Yi; Cenko, S. Bradley; Rebbapragada, Umaa D.; Woźniak, P. R.; Filippenko, Alexei V.; Clubb, K. I.; Nugent, Peter E.; Pan, Y.-C.; Badenes, C.; Howell, D. Andrew; Valenti, Stefano; Sand, David; Sollerman, J.; Johansson, Joel; Leonard, Douglas C.; Horst, J. Chuck; Armen, Stephen F.; Fedrow, Joseph M.; Quimby, Robert M.; Mazzali, Paulo; Pian, Elena; Sternberg, Assaf; Matheson, Thomas; Sullivan, M.; Maguire, K.; Lazarevic, Sanja

2016-03-01

During the first few days after explosion, Type II supernovae (SNe) are dominated by relatively simple physics. Theoretical predictions regarding early-time SN light curves in the ultraviolet (UV) and optical bands are thus quite robust. We present, for the first time, a sample of 57 R-band SN II light curves that are well-monitored during their rise, with \\gt 5 detections during the first 10 days after discovery, and a well-constrained time of explosion to within 1-3 days. We show that the energy per unit mass (E/M) can be deduced to roughly a factor of five by comparing early-time optical data to the 2011 model of Rabinak & Waxman, while the progenitor radius cannot be determined based on R-band data alone. We find that SN II explosion energies span a range of E/M = (0.2-20) × 1051 erg/(10 {M}⊙ ), and have a mean energy per unit mass of < E/M> =0.85× {10}51 erg/(10 {M}⊙ ), corrected for Malmquist bias. Assuming a small spread in progenitor masses, this indicates a large intrinsic diversity in explosion energy. Moreover, E/M is positively correlated with the amount of 56Ni produced in the explosion, as predicted by some recent models of core-collapse SNe. We further present several empirical correlations. The peak magnitude is correlated with the decline rate ({{Δ }}{m}15), the decline rate is weakly correlated with the rise time, and the rise time is not significantly correlated with the peak magnitude. Faster declining SNe are more luminous and have longer rise times. This limits the possible power sources for such events.

Type II Supernova Energetics and Comparison of Light Curves to Shock-Cooling Models

NASA Technical Reports Server (NTRS)

Rubin, Adam; Gal-Yam, Avishay; Cia, Annalisa De; Horesh, Assaf; Khazov, Danny; Ofek, Eran O.; Kulkarni, S. R.; Arcavi, Iair; Manulis, Ilan; Cenko, S. Bradley

2016-01-01

During the first few days after explosion, Type II supernovae (SNe) are dominated by relatively simple physics. Theoretical predictions regarding early-time SN light curves in the ultraviolet (UV) and optical bands are thus quite robust. We present, for the first time, a sample of 57 R-band SN II light curves that are well-monitored during their rise, with greater than 5 detections during the first 10 days after discovery, and a well-constrained time of explosion to within 13 days. We show that the energy per unit mass (E/M) can be deduced to roughly a factor of five by comparing early-time optical data to the 2011 model of Rabinak Waxman, while the progenitor radius cannot be determined based on R-band data alone. We find that SN II explosion energies span a range of EM = (0.2-20) x 10(exp 51) erg/(10 M stellar mass), and have a mean energy per unit mass of E/ M = 0.85 x 10(exp 51) erg(10 stellar mass), corrected for Malmquist bias. Assuming a small spread in progenitor masses, this indicates a large intrinsic diversity in explosion energy. Moreover, E/M is positively correlated with the amount of Ni-56 produced in the explosion, as predicted by some recent models of core-collapse SNe. We further present several empirical correlations. The peak magnitude is correlated with the decline rate (Delta m(sub15), the decline rate is weakly correlated with the rise time, and the rise time is not significantly correlated with the peak magnitude. Faster declining SNe are more luminous and have longer rise times. This limits the possible power sources for such events.

Regional temperature and precipitation changes under high-end (≥4°C) global warming.

PubMed

Sanderson, M G; Hemming, D L; Betts, R A

2011-01-13

Climate models vary widely in their projections of both global mean temperature rise and regional climate changes, but are there any systematic differences in regional changes associated with different levels of global climate sensitivity? This paper examines model projections of climate change over the twenty-first century from the Intergovernmental Panel on Climate Change Fourth Assessment Report which used the A2 scenario from the IPCC Special Report on Emissions Scenarios, assessing whether different regional responses can be seen in models categorized as 'high-end' (those projecting 4°C or more by the end of the twenty-first century relative to the preindustrial). It also identifies regions where the largest climate changes are projected under high-end warming. The mean spatial patterns of change, normalized against the global rate of warming, are generally similar in high-end and 'non-high-end' simulations. The exception is the higher latitudes, where land areas warm relatively faster in boreal summer in high-end models, but sea ice areas show varying differences in boreal winter. Many continental interiors warm approximately twice as fast as the global average, with this being particularly accentuated in boreal summer, and the winter-time Arctic Ocean temperatures rise more than three times faster than the global average. Large temperature increases and precipitation decreases are projected in some of the regions that currently experience water resource pressures, including Mediterranean fringe regions, indicating enhanced pressure on water resources in these areas.

78 FR 35567 - Safety Zone; Lower Mississippi River, Mile Marker 219 to Mile Marker 229, in the Vicinity of Port...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-13

... Mississippi River in this area have risen very rapidly, creating a faster than normal current that is a hazard... Rouge gauge has reached 33 feet and continues to rise. This elevated water level is creating a faster... event the Baton Rouge Gage is reading below 33 feet and falling. The Captain of the Port, New Orleans or...

Carbon Atom Hybridization Matters: Ultrafast Humidity Response of Graphdiyne Oxides.

PubMed

Yan, Hailong; Guo, Shuyue; Wu, Fei; Yu, Ping; Liu, Huibiao; Li, Yuliang; Mao, Lanqun

2018-04-03

Graphdiyne oxide (GDO), the oxidized form of graphdiyne (GDY), exhibits an ultrafast humidity response with an unprecedented response speed (ca. 7 ms), which is three times faster than that of graphene oxide (GO) with the same thickness and O/C ratio. The ultrafast humidity response of GDO is considered to benefit from the unique carbon hybridization of GDO, which contains acetylenic bonds that are more electron-withdrawing than ethylenic bonds in GO, consequently giving rise to a faster binding rate with water. This distinctive structure-based property enables the fabrication of a novel GDO-based humidity sensor with an ultrafast response speed and good selectivity against other kinds of gas molecules as well as high sensitivity. These properties allow the sensor to accurately monitor the respiration rate change of human and hypoxic rats. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High methane natural gas/air explosion characteristics in confined vessel.

PubMed

Tang, Chenglong; Zhang, Shuang; Si, Zhanbo; Huang, Zuohua; Zhang, Kongming; Jin, Zebing

2014-08-15

The explosion characteristics of high methane fraction natural gas were investigated in a constant volume combustion vessel at different initial conditions. Results show that with the increase of initial pressure, the peak explosion pressure, the maximum rate of pressure rise increase due to a higher amount (mass) of flammable mixture, which delivers an increased amount of heat. The increased total flame duration and flame development time result as a consequence of the higher amount of flammable mixture. With the increase of the initial temperature, the peak explosion pressures decrease, but the pressure increase during combustion is accelerated, which indicates a faster flame speed and heat release rate. The maximum value of the explosion pressure, the maximum rate of pressure rise, the minimum total combustion duration and the minimum flame development time is observed when the equivalence ratio of the mixture is 1.1. Additionally, for higher methane fraction natural gas, the explosion pressure and the maximum rate of pressure rise are slightly decreased, while the combustion duration is postponed. The combustion phasing is empirically correlated with the experimental parameters with good fitting performance. Furthermore, the addition of dilute gas significantly reduces the explosion pressure, the maximum rate of pressure rise and postpones the flame development and this flame retarding effect of carbon dioxide is stronger than that of nitrogen. Copyright © 2014 Elsevier B.V. All rights reserved.

BPcontrol

PubMed Central

Carrera, Adrián; Pifarré, Marc; Vilaplana, Jordi; Cuadrado, Josep; Solsona, Sara; Mateo, Jordi

2016-01-01

Summary Background Hypertension or high blood pressure is on the rise. Not only does it affect the elderly but is also increasingly spreading to younger sectors of the population. Treating this condition involves exhaustive monitoring of patients. The current mobile health services can be improved to perform this task more effectively. Objective To develop a useful, user-friendly, robust and efficient app, to monitor hypertensive patients and adapted to the particular requirements of hypertension. Methods This work presents BPcontrol, an Android and iOS app that allows hypertensive patients to communicate with their health-care centers, thus facilitating monitoring and diagnosis. Usability, robustness and efficiency factors for BPcontrol were evaluated for different devices and operating systems (Android, iOS and system-aware). Furthermore, its features were compared with other similar apps in the literature. Results BPcontrol is robust and user-friendly. The respective start-up efficiency of the Android and iOS versions of BPcontrol were 2.4 and 8.8 times faster than a system-aware app. Similar values were obtained for the communication efficiency (7.25 and 11.75 times faster for the Android and iOS respectively). When comparing plotting performance, BPcontrol was on average 2.25 times faster in the Android case. Most of the apps in the literature have no communication with a server, thus making it impossible to compare their performance with BPcontrol. Conclusions Its optimal design and the good behavior of its facilities make BPcontrol a very promising mobile app for monitoring hypertensive patients. PMID:27924346

BPcontrol. A Mobile App to Monitor Hypertensive Patients.

PubMed

Carrera, Adrian; Pifarré, Marc; Vilaplana, Jordi; Cuadrado, Josep; Solsona, Sara; Mateo, Jordi; Solsona, Francesc

2016-12-07

Hypertension or high blood pressure is on the rise. Not only does it affect the elderly but is also increasingly spreading to younger sectors of the population. Treating this condition involves exhaustive monitoring of patients. The current mobile health services can be improved to perform this task more effectively. To develop a useful, user-friendly, robust and efficient app, to monitor hypertensive patients and adapted to the particular requirements of hypertension. This work presents BPcontrol, an Android and iOS app that allows hypertensive patients to communicate with their health-care centers, thus facilitating monitoring and diagnosis. Usability, robustness and efficiency factors for BPcontrol were evaluated for different devices and operating systems (Android, iOS and system-aware). Furthermore, its features were compared with other similar apps in the literature. BPcontrol is robust and user-friendly. The respective start-up efficiency of the Android and iOS versions of BPcontrol were 2.4 and 8.8 times faster than a system-aware app. Similar values were obtained for the communication efficiency (7.25 and 11.75 times faster for the Android and iOS respectively). When comparing plotting performance, BPcontrol was on average 2.25 times faster in the Android case. Most of the apps in the literature have no communication with a server, thus making it impossible to compare their performance with BPcontrol. Its optimal design and the good behavior of its facilities make BPcontrol a very promising mobile app for monitoring hypertensive patients.

Sedimentation and response to sea-level rise of a restored marsh with reduced tidal exchange: Comparison with a natural tidal marsh

USGS Publications Warehouse

Vandenbruwaene, W.; Maris, T.; Cahoon, D.R.; Meire, P.; Temmerman, S.

2011-01-01

Along coasts and estuaries, formerly embanked land is increasingly restored into tidal marshes in order to re-establish valuable ecosystem services, such as buffering against flooding. Along the Scheldt estuary (Belgium), tidal marshes are restored on embanked land by allowing a controlled reduced tide (CRT) into a constructed basin, through a culvert in the embankment. In this way tidal water levels are significantly lowered (ca. 3 m) so that a CRT marsh can develop on formerly embanked land with a ca. 3 m lower elevation than the natural tidal marshes. In this study we compared the long-term change in elevation (ΔE) within a CRT marsh and adjacent natural tidal marsh. Over a period of 4 years, the observed spatio-temporal variations in ΔE rate were related to variations in inundation depth, and this relationship was not significantly different for the CRT marsh and natural tidal marsh. A model was developed to simulate the ΔE over the next century. (1) Under a scenario without mean high water level (MHWL) rise in the estuary, the model shows that the marsh elevation-ΔE feedback that is typical for a natural tidal marsh (i.e. rising marsh elevation results in decreasing inundation depth and therefore a decreasing increase in elevation) is absent in the basin of the CRT marsh. This is because tidal exchange of water volumes between the estuary and CRT marsh are independent from the CRT marsh elevation but dependent on the culvert dimensions. Thus the volume of water entering the CRT remains constant regardless of the marsh elevation. Consequently the CRT MHWL follows the increase in CRT surface elevation, resulting after 75 years in a 2–2.5 times larger elevation gain in the CRT marsh, and a faster reduction of spatial elevation differences. (2) Under a scenario of constant MHWL rise (historical rate of 1.5 cm a-1), the equilibrium elevation (relative to MHWL) is 0.13 m lower in the CRT marsh and is reached almost 2 times faster. (3) Under a scenario of accelerated MHWL rise (acceleration of 0.02 cm a-1), the CRT marsh is much less able to keep up with the MHWL rise; after 75 years the CRT elevation is already 0.21 m lower than for the natural marsh. In conclusion, this study demonstrates that although short-term (4 years) ΔE rates are similar in a restored CRT marsh and natural tidal marsh, these ecosystems may evolve differently in response to sea-level rise in the longer term (10–100 years).

Natural Language Interfaces to Database Systems

DTIC Science & Technology

1988-10-01

the power was nff to avoid re-entering data for each run of the calculations. External physical devices were developed such as punched tape and...given rise to more powerful or faster tools. Today, operations with the latest fifth generation database management system are not going to be any faster...database does not represent an evolution of greater power or speed. The fascinating aspect is that it represents an evolution of usability and more

A Hidden Cause of Rising Tuition: Tuition Discounting in Public Colleges and Universities. The Progress of Education Reform. Volume 15, Number 4

ERIC Educational Resources Information Center

Gianneschi, Matt; Pingel, Sarah

2014-01-01

Why does tuition increase faster than inflation? And why does tuition continue to increase even when states increase their investments in public colleges and universities? These questions have perplexed policymakers and higher education consumers alike. Though tuition setting can be very complicated, one of the drivers for rising costs is price…

Infrastructure effects on estuarine wetlands increase their vulnerability to sea level rise

NASA Astrophysics Data System (ADS)

Rodriguez, Jose; Saco, Patricia; Sandi, Steven; Saintilan, Neil; Riccardi, Gerardo

2017-04-01

At the regional and global scales, coastal management and planning for future sea level rise scenarios is typically supported by modelling tools that predict the expected inundation extent. These tools rely on a number of simplifying assumptions that, in some cases, may result in important miscalculation of the inundation effects. One of such cases is estuarine wetlands, where vegetation strongly depends on both the magnitude and the timing of inundation. Many coastal wetlands display flow restrictions due to infrastructure or drainage works, which produce alterations to the inundation patterns that can not be captured by conventional models. In this contribution we explore the effects of flow restrictions on inundation patterns under sea level rise conditions in estuarine wetlands. We use a spatially-distributed dynamic wetland ecogeomorphological model that not only incorporates the effects of flow restrictions due to culverts, bridges and weirs as well as vegetation, but also considers that vegetation changes as a consequence of increasing inundation. We also consider the ability of vegetation to capture sediment and produce accretion. We apply our model to an estuarine wetland in Australia and show that our model predicts a much faster wetland loss due to sea level rise than conventional approaches.

Sea level change: lessons from the geologic record

USGS Publications Warehouse

,

1995-01-01

Rising sea level is potentially one of the most serious impacts of climatic change. Even a small sea level rise would have serious economic consequences because it would cause extensive damage to the world's coastal regions. Sea level can rise in the future because the ocean surface can expand due to warming and because polar ice sheets and mountain glaciers can melt, increasing the ocean's volume of water. Today, ice caps on Antarctica and Greenland contain 91 and 8 percent of the world's ice, respectively. The world's mountain glaciers together contain only about 1 percent. Melting all this ice would raise sea level about 80 meters. Although this extreme scenario is not expected, geologists know that sea level can rise and fall rapidly due to changing volume of ice on continents. For example, during the last ice age, about 18,000 years ago, continental ice sheets contained more than double the modem volume of ice. As ice sheets melted, sea level rose 2 to 3 meters per century, and possibly faster during certain times. During periods in which global climate was very warm, polar ice was reduced and sea level was higher than today.

Recruitment of faster motor units is associated with greater rates of fascicle strain and rapid changes in muscle force during locomotion

PubMed Central

Lee, Sabrina S. M.; de Boef Miara, Maria; Arnold, Allison S.; Biewener, Andrew A.; Wakeling, James M.

2013-01-01

SUMMARY Animals modulate the power output needed for different locomotor tasks by changing muscle forces and fascicle strain rates. To generate the necessary forces, appropriate motor units must be recruited. Faster motor units have faster activation–deactivation rates than slower motor units, and they contract at higher strain rates; therefore, recruitment of faster motor units may be advantageous for tasks that involve rapid movements or high rates of work. This study identified motor unit recruitment patterns in the gastrocnemii muscles of goats and examined whether faster motor units are recruited when locomotor speed is increased. The study also examined whether locomotor tasks that elicit faster (or slower) motor units are associated with increased (or decreased) in vivo tendon forces, force rise and relaxation rates, fascicle strains and/or strain rates. Electromyography (EMG), sonomicrometry and muscle-tendon force data were collected from the lateral and medial gastrocnemius muscles of goats during level walking, trotting and galloping and during inclined walking and trotting. EMG signals were analyzed using wavelet and principal component analyses to quantify changes in the EMG frequency spectra across the different locomotor conditions. Fascicle strain and strain rate were calculated from the sonomicrometric data, and force rise and relaxation rates were determined from the tendon force data. The results of this study showed that faster motor units were recruited as goats increased their locomotor speeds from level walking to galloping. Slow inclined walking elicited EMG intensities similar to those of fast level galloping but different EMG frequency spectra, indicating that recruitment of the different motor unit types depended, in part, on characteristics of the task. For the locomotor tasks and muscles analyzed here, recruitment patterns were generally associated with in vivo fascicle strain rates, EMG intensity and tendon force. Together, these data provide new evidence that changes in motor unit recruitment have an underlying mechanical basis, at least for certain locomotor tasks. PMID:22972893

Recruitment of faster motor units is associated with greater rates of fascicle strain and rapid changes in muscle force during locomotion.

PubMed

Lee, Sabrina S M; de Boef Miara, Maria; Arnold, Allison S; Biewener, Andrew A; Wakeling, James M

2013-01-15

Animals modulate the power output needed for different locomotor tasks by changing muscle forces and fascicle strain rates. To generate the necessary forces, appropriate motor units must be recruited. Faster motor units have faster activation-deactivation rates than slower motor units, and they contract at higher strain rates; therefore, recruitment of faster motor units may be advantageous for tasks that involve rapid movements or high rates of work. This study identified motor unit recruitment patterns in the gastrocnemii muscles of goats and examined whether faster motor units are recruited when locomotor speed is increased. The study also examined whether locomotor tasks that elicit faster (or slower) motor units are associated with increased (or decreased) in vivo tendon forces, force rise and relaxation rates, fascicle strains and/or strain rates. Electromyography (EMG), sonomicrometry and muscle-tendon force data were collected from the lateral and medial gastrocnemius muscles of goats during level walking, trotting and galloping and during inclined walking and trotting. EMG signals were analyzed using wavelet and principal component analyses to quantify changes in the EMG frequency spectra across the different locomotor conditions. Fascicle strain and strain rate were calculated from the sonomicrometric data, and force rise and relaxation rates were determined from the tendon force data. The results of this study showed that faster motor units were recruited as goats increased their locomotor speeds from level walking to galloping. Slow inclined walking elicited EMG intensities similar to those of fast level galloping but different EMG frequency spectra, indicating that recruitment of the different motor unit types depended, in part, on characteristics of the task. For the locomotor tasks and muscles analyzed here, recruitment patterns were generally associated with in vivo fascicle strain rates, EMG intensity and tendon force. Together, these data provide new evidence that changes in motor unit recruitment have an underlying mechanical basis, at least for certain locomotor tasks.

Explaining Cold-Pulse Dynamics in Tokamak Plasmas Using Local Turbulent Transport Models

DOE PAGES

Rodriguez-Fernandez, P.; White, A. E.; Howard, N. T.; ...

2018-02-16

A long-standing enigma in plasma transport has been resolved by modeling of cold-pulse experiments conducted on the Alcator C-Mod tokamak. Controlled edge cooling of fusion plasmas triggers core electron heating on time scales faster than an energy confinement time, which has long been interpreted as strong evidence of nonlocal transport. Here, this Letter shows that the steady-state profiles, the cold-pulse rise time, and disappearance at higher density as measured in these experiments are successfully captured by a recent local quasilinear turbulent transport model, demonstrating that the existence of nonlocal transport phenomena is not necessary for explaining the behavior and timemore » scales of cold-pulse experiments in tokamak plasmas.« less

Explaining Cold-Pulse Dynamics in Tokamak Plasmas Using Local Turbulent Transport Models

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

Rodriguez-Fernandez, P.; White, A. E.; Howard, N. T.

A long-standing enigma in plasma transport has been resolved by modeling of cold-pulse experiments conducted on the Alcator C-Mod tokamak. Controlled edge cooling of fusion plasmas triggers core electron heating on time scales faster than an energy confinement time, which has long been interpreted as strong evidence of nonlocal transport. Here, this Letter shows that the steady-state profiles, the cold-pulse rise time, and disappearance at higher density as measured in these experiments are successfully captured by a recent local quasilinear turbulent transport model, demonstrating that the existence of nonlocal transport phenomena is not necessary for explaining the behavior and timemore » scales of cold-pulse experiments in tokamak plasmas.« less

Financing Health Care: Businesses, Households, and Governments, 1987-2003

PubMed Central

Cowan, Cathy A.; Hartman, Micah B.

2005-01-01

This article provides estimates of health care expenditures by businesses, households, and governments for 1987-2003. Sponsors that finance public and private health insurance programs and other payers face increasing challenges as health care cost rise. Their capacity to support rising costs was particularly strained during the recent economic recession, with the Federal Government's burden measured against revenue available for this purpose growing faster than for other sponsors. PMID:25372083

The Effect of Driver Rise-Time on Pinch Current and its Impact on Plasma Focus Performance and Neutron Yield

NASA Astrophysics Data System (ADS)

Sears, Jason; Schmidt, Andrea; Link, Anthony; Welch, Dale

2016-10-01

Experiments have suggested that dense plasma focus (DPF) neutron yield increases with faster drivers [Decker NIMP 1986]. Using the particle-in-cell code LSP [Schmidt PRL 2012], we reproduce this trend in a kJ DPF [Ellsworth 2014], and demonstrate how driver rise time is coupled to neutron output. We implement a 2-D model of the plasma focus including self-consistent circuit-driven boundary conditions. Driver capacitance and voltage are varied to modify the current rise time, and anode length is adjusted so that run-in coincides with the peak current. We observe during run down that magnetohydrodynamic (MHD) instabilities of the sheath shed blobs of plasma that remain in the inter-electrode gap during run in. This trailing plasma later acts as a low-inductance restrike path that shunts current from the pinch during maximum compression. While the MHD growth rate increases slightly with driver speed, the shorter anode of the fast driver allows fewer e-foldings and hence reduces the trailing mass between electrodes. As a result, the fast driver postpones parasitic restrikes and maintains peak current through the pinch during maximum compression. The fast driver pinch therefore achieves best simultaneity between its ion beam and peak target density, which maximizes neutron production. Prepared by LLNL under Contract DE-AC52-07NA27344.

Fermi GBM Observations of Terrestrial Gamma-ray Flashes

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

Briggs, Michael S.

2011-09-21

Terrestrial Gamma-ray Flashes are short pulses of energetic radiation associated with thunderstorms and lightning. While the Gamma-ray Burst Monitor (GBM) on Fermi was designed to observe gamma-ray bursts, its large BGO detectors are excellent for observing TGFs. Using GBM, TGF pulses are seen to either be symmetrical or have faster rise time than fall times. Some TGFs are resolved into double, partially overlapping pulses. Using ground-based radio observations of lightning from the World Wide Lightning Location Network (WWLLN), TGFs and their associated lightning are found to be simultaneous to {approx_equal}40 {mu} s. The lightning locations are typically within 300 kmmore » of the sub-spacecraft point.« less

Pulse power switch development

NASA Astrophysics Data System (ADS)

Harvey, R.; Gallagher, H.; Hansen, S.

1980-01-01

The objective of this study program has been to define an optimum technical approach to the longer range goal of achieving practical high repetition rate high power spark gap switches. Requirements and possible means of extending the state of the art of crossed field closing switches, vacuum spark gaps, and pressurized spark gaps are presented with emphasis on reliable, efficient and compact devices operable in burst mode at 250-300 kV, 40-60 kA, =1 kHz with approximately 50 nsec pulses rising in approximately 3 ns. Models of these devices are discussed which are based upon published and generated design data and on underlying physical principles. Based upon its relative advantages, limitations and tradeoffs we conclude that the Hughes Crossatron switch is the nearest term approach to reach the switch goal levels. Theoretical, experimental, and computer simulation models of the plasma show a collective ion acceleration mechanism to be active which is predicted to result in current rise times approaching 10 nsec. A preliminary design concept is presented. For faster rise times we have shown a vacuum surface flashover switch to be an interesting candidate. This device is limited by trigger instabilities and will require further basic development. The problem areas relevant to high pressure spark gaps are reviewed.

Listeners' comprehension of uptalk in spontaneous speech.

PubMed

Tomlinson, John M; Fox Tree, Jean E

2011-04-01

Listeners' comprehension of phrase final rising pitch on declarative utterances, or uptalk, was examined to test the hypothesis that prolongations might differentiate conflicting functions of rising pitch. In Experiment 1 we found that listeners rated prolongations as indicating more speaker uncertainty, but that rising pitch was unrelated to ratings. In Experiment 2 we found that prolongations interacted with rising pitch when listeners monitored for words in the subsequent utterance. Words preceded by prolonged uptalk were monitored faster than words preceded by non-prolonged uptalk. In Experiment 3 we found that the interaction between rising pitch and prolongations depended on listeners' beliefs about speakers' mental states. Results support the theory that temporal and situational context are important in determining intonational meaning. Copyright © 2010 Elsevier B.V. All rights reserved.

The changing timing of births in Iran: an explanation of the rise and fall in fertility after the 1979 Islamic Revolution.

PubMed

Erfani, Amir; McQuillan, Kevin

2014-01-01

Studies exploring the course of period fertility in Iran after the 1979 Islamic Revolution have not examined systematically the role played by changes in the timing of births. Using retrospective data from the 2000 Iran Demographic and Health Survey and frailty hazard models, this study finds that the rise in fertility in the early 1980s was due to faster transitions to the first birth among all social groups of women and to the fourth birth largely among illiterate and less educated women. In contrast, the rapid fertility decline after 1985 is attributed to slower transition to successive births, especially to the second, third, and fourth births. These findings point to the importance of education and contraceptive use (measured by length of previous birth interval) as key determinants of birth timing in Iran. Interaction between age at marriage and education positively influenced the timing of births, with stronger effects among highly educated women, suggesting that the onset of rapid fertility decline was likely driven by these highly educated women. Another interaction between the gender of prior children and education shows that birth timing, even among highly educated women, appears to have been influenced by son preference in Iran.

Fast core rotation in red-giant stars as revealed by gravity-dominated mixed modes.

PubMed

Beck, Paul G; Montalban, Josefina; Kallinger, Thomas; De Ridder, Joris; Aerts, Conny; García, Rafael A; Hekker, Saskia; Dupret, Marc-Antoine; Mosser, Benoit; Eggenberger, Patrick; Stello, Dennis; Elsworth, Yvonne; Frandsen, Søren; Carrier, Fabien; Hillen, Michel; Gruberbauer, Michael; Christensen-Dalsgaard, Jørgen; Miglio, Andrea; Valentini, Marica; Bedding, Timothy R; Kjeldsen, Hans; Girouard, Forrest R; Hall, Jennifer R; Ibrahim, Khadeejah A

2011-12-07

When the core hydrogen is exhausted during stellar evolution, the central region of a star contracts and the outer envelope expands and cools, giving rise to a red giant. Convection takes place over much of the star's radius. Conservation of angular momentum requires that the cores of these stars rotate faster than their envelopes; indirect evidence supports this. Information about the angular-momentum distribution is inaccessible to direct observations, but it can be extracted from the effect of rotation on oscillation modes that probe the stellar interior. Here we report an increasing rotation rate from the surface of the star to the stellar core in the interiors of red giants, obtained using the rotational frequency splitting of recently detected 'mixed modes'. By comparison with theoretical stellar models, we conclude that the core must rotate at least ten times faster than the surface. This observational result confirms the theoretical prediction of a steep gradient in the rotation profile towards the deep stellar interior.

On the psychology of the recognition heuristic: retrieval primacy as a key determinant of its use.

PubMed

Pachur, Thorsten; Hertwig, Ralph

2006-09-01

The recognition heuristic is a prime example of a boundedly rational mind tool that rests on an evolved capacity, recognition, and exploits environmental structures. When originally proposed, it was conjectured that no other probabilistic cue reverses the recognition-based inference (D. G. Goldstein & G. Gigerenzer, 2002). More recent studies challenged this view and gave rise to the argument that recognition enters inferences just like any other probabilistic cue. By linking research on the heuristic with research on recognition memory, the authors argue that the retrieval of recognition information is not tantamount to the retrieval of other probabilistic cues. Specifically, the retrieval of subjective recognition precedes that of an objective probabilistic cue and occurs at little to no cognitive cost. This retrieval primacy gives rise to 2 predictions, both of which have been empirically supported: Inferences in line with the recognition heuristic (a) are made faster than inferences inconsistent with it and (b) are more prevalent under time pressure. Suspension of the heuristic, in contrast, requires additional time, and direct knowledge of the criterion variable, if available, can trigger such suspension. Copyright 2006 APA

EXPONENTIAL TIME DIFFERENCING FOR HODGKIN–HUXLEY-LIKE ODES

PubMed Central

Börgers, Christoph; Nectow, Alexander R.

2013-01-01

Several authors have proposed the use of exponential time differencing (ETD) for Hodgkin–Huxley-like partial and ordinary differential equations (PDEs and ODEs). For Hodgkin–Huxley-like PDEs, ETD is attractive because it can deal effectively with the stiffness issues that diffusion gives rise to. However, large neuronal networks are often simulated assuming “space-clamped” neurons, i.e., using the Hodgkin–Huxley ODEs, in which there are no diffusion terms. Our goal is to clarify whether ETD is a good idea even in that case. We present a numerical comparison of first- and second-order ETD with standard explicit time-stepping schemes (Euler’s method, the midpoint method, and the classical fourth-order Runge–Kutta method). We find that in the standard schemes, the stable computation of the very rapid rising phase of the action potential often forces time steps of a small fraction of a millisecond. This can result in an expensive calculation yielding greater overall accuracy than needed. Although it is tempting at first to try to address this issue with adaptive or fully implicit time-stepping, we argue that neither is effective here. The main advantage of ETD for Hodgkin–Huxley-like systems of ODEs is that it allows underresolution of the rising phase of the action potential without causing instability, using time steps on the order of one millisecond. When high quantitative accuracy is not necessary and perhaps, because of modeling inaccuracies, not even useful, ETD allows much faster simulations than standard explicit time-stepping schemes. The second-order ETD scheme is found to be substantially more accurate than the first-order one even for large values of Δt. PMID:24058276

Future Cognitive Ability: US IQ Prediction until 2060 Based on NAEP.

PubMed

Rindermann, Heiner; Pichelmann, Stefan

2015-01-01

The US National Assessment of Educational Progress (NAEP) measures cognitive competences in reading and mathematics of US students (last 2012 survey N = 50,000). The long-term development based on results from 1971 to 2012 allows a prediction of future cognitive trends. For predicting US averages also demographic trends have to be considered. The largest groups' (White) average of 1978/80 was set at M = 100 and SD = 15 and was used as a benchmark. Based on two past NAEP development periods for 17-year-old students, 1978/80 to 2012 (more optimistic) and 1992 to 2012 (more pessimistic), and demographic projections from the US Census Bureau, cognitive trends until 2060 for the entire age cohort and ethnic groups were estimated. Estimated population averages for 2060 are 103 (optimistic) or 102 (pessimistic). The average rise per decade is dec = 0.76 or 0.45 IQ points. White-Black and White-Hispanic gaps are declining by half, Asian-White gaps treble. The catch-up of minorities (their faster ability growth) contributes around 2 IQ to the general rise of 3 IQ; however, their larger demographic increase reduces the general rise at about the similar amount (-1.4 IQ). Because minorities with faster ability growth also rise in their population proportion the interactive term is positive (around 1 IQ). Consequences for economic and societal development are discussed.

Future Cognitive Ability: US IQ Prediction until 2060 Based on NAEP

PubMed Central

2015-01-01

The US National Assessment of Educational Progress (NAEP) measures cognitive competences in reading and mathematics of US students (last 2012 survey N = 50,000). The long-term development based on results from 1971 to 2012 allows a prediction of future cognitive trends. For predicting US averages also demographic trends have to be considered. The largest groups’ (White) average of 1978/80 was set at M = 100 and SD = 15 and was used as a benchmark. Based on two past NAEP development periods for 17-year-old students, 1978/80 to 2012 (more optimistic) and 1992 to 2012 (more pessimistic), and demographic projections from the US Census Bureau, cognitive trends until 2060 for the entire age cohort and ethnic groups were estimated. Estimated population averages for 2060 are 103 (optimistic) or 102 (pessimistic). The average rise per decade is dec = 0.76 or 0.45 IQ points. White-Black and White-Hispanic gaps are declining by half, Asian-White gaps treble. The catch-up of minorities (their faster ability growth) contributes around 2 IQ to the general rise of 3 IQ; however, their larger demographic increase reduces the general rise at about the similar amount (-1.4 IQ). Because minorities with faster ability growth also rise in their population proportion the interactive term is positive (around 1 IQ). Consequences for economic and societal development are discussed. PMID:26460731

Dynamics of glass-forming liquids. XIX. Rise and decay of field induced anisotropy in the non-linear regime

NASA Astrophysics Data System (ADS)

Young-Gonzales, Amanda R.; Samanta, Subarna; Richert, Ranko

2015-09-01

For glycerol and three monohydroxy alcohols, we have measured the non-linear dielectric effects resulting from the application and removal of a high dc bias electric field. The field effects are detected by virtue of a small amplitude harmonic field, from which time resolved changes in the dielectric loss are derived. The changes in permittivity are dominated by modifications of the time constants (rather than amplitudes) which display two contributions: a heating-like decrease of relaxation times that originates from the time dependent field when the bias is switched on and off and a slowing down of the dynamics resulting from the field induced reduction of configurational entropy. As observed for the electro-optical Kerr effect, the rise of the entropy change is slower than its decay, a feature that we rationalize on the basis of the quadratic dependence of the entropy change on polarization. For glycerol, the observed steady state level of the field induced shift of the glass transition temperature (+84 mK) matches the expectation based on the entropy change and its impact on dynamics via the Adam-Gibbs relation (+88 mK). For the alcohols, these non-linear effects rise and decay on the time scales of the prominent dielectric Debye process, underscoring the relation of these features to polarization anisotropy, opposed to mechanical or enthalpy relaxation which are orders of magnitude faster in these systems. A model is discussed which captures the observed magnitudes as well as time dependences in a near quantitative fashion. It is demonstrated that the high bias field modifies the response of polarization to the ac field, including a temporary change in the low field susceptibility.

Self-excitation of microwave oscillations in plasma-assisted slow-wave oscillators by an electron beam with a movable focus

NASA Astrophysics Data System (ADS)

Bliokh, Yu. P.; Nusinovich, G. S.; Shkvarunets, A. G.; Carmel, Y.

2004-10-01

Plasma-assisted slow-wave oscillators (pasotrons) operate without external magnetic fields, which makes these devices quite compact and lightweight. Beam focusing in pasotrons is provided by ions, which appear in the device due to the impact ionization of a neutral gas by beam electrons. Typically, the ionization time is on the order of the rise time of the beam current. This means that, during the rise of the current, beam focusing by ions becomes stronger. Correspondingly, a beam of electrons, which was initially diverging radially due to the self-electric field, starts to be focused by ions, and this focus moves towards the gun as the ion density increases. This feature makes the self-excitation of electromagnetic (em) oscillations in pasotrons quite different from practically all other microwave sources where em oscillations are excited by a stationary electron beam. The process of self-excitation of em oscillations has been studied both theoretically and experimentally. It is shown that in pasotrons, during the beam current rise the amount of current entering the interaction space and the beam coupling to the em field vary. As a result, the self-excitation can proceed faster than in conventional microwave sources with similar operating parameters such as the operating frequency, cavity quality-factor and the beam current and voltage.

Technological advances in bovine mastitis diagnosis: an overview.

PubMed

Duarte, Carla M; Freitas, Paulo P; Bexiga, Ricardo

2015-11-01

Bovine mastitis is an economic burden for dairy farmers and preventive control measures are crucial for the sustainability of any dairy business. The identification of etiological agents is necessary in controlling the disease, reducing risk of chronic infections and targeting antimicrobial therapy. The suitability of a detection method for routine diagnosis depends on several factors, including specificity, sensitivity, cost, time in producing results, and suitability for large-scale sampling of milk. This article focuses on current methodologies for identification of mastitis pathogens and for detection of inflammation, as well as the advantages and disadvantages of different methods. Emerging technologies, such as transcriptome and proteome analyses and nano- and microfabrication of portable devices, offer promising, sensitive methods for advanced detection of mastitis pathogens and biomarkers of inflammation. The demand for alternative, fast, and reliable diagnostic procedures is rising as farms become bigger. Several examples of technological and scientific advances are summarized which have given rise to more sensitive, reliable and faster diagnostic results. © 2015 The Author(s).

Lightning criteria relative to space shuttles: Currents and electric field intensity in Florida lightning

NASA Technical Reports Server (NTRS)

Uman, M. A.; Mclain, D. K.

1972-01-01

The measured electric field intensities of 161 lightning strokes in 39 flashes which occurred between 1 and 35 km from an observation point at Kennedy Space Center, Florida during June and July of 1971 have been analyzed to determine the lightning channel currents which produced the fields. In addition, typical channel currents are derived and from these typical electric fields at distances between 0.5 and 100 km are computed and presented. On the basis of the results recommendations are made for changes in the specification of lightning properties relative to space vehicle design as given in NASA TMX-64589 (Daniels, 1971). The small sample of lightning analyzed yielded several peak currents in the 100 kA range. Several current rise-times from zero to peak of 0.5 microsec or faster were found; and the fastest observed current rate-of-rise was near 200 kA/microsec. The various sources of error are discussed.

Contamination sources, prevention, and research

USDA-ARS?s Scientific Manuscript database

Contamination is defined as anything other than cotton in cotton lint. Worldwide, contamination is on the rise and plastic contamination has increased at a faster rate than contamination overall. In the U.S., there are many sources of plastic contaminants, such as plastic trash that collects in cott...

Experimental investigations of argon spark gap recovery times by developing a high voltage double pulse generator.

PubMed

Reddy, C S; Patel, A S; Naresh, P; Sharma, Archana; Mittal, K C

2014-06-01

The voltage recovery in a spark gap for repetitive switching has been a long research interest. A two-pulse technique is used to determine the voltage recovery times of gas spark gap switch with argon gas. First pulse is applied to the spark gap to over-volt the gap and initiate the breakdown and second pulse is used to determine the recovery voltage of the gap. A pulse transformer based double pulse generator capable of generating 40 kV peak pulses with rise time of 300 ns and 1.5 μs FWHM and with a delay of 10 μs-1 s was developed. A matrix transformer topology is used to get fast rise times by reducing L(l)C(d) product in the circuit. Recovery Experiments have been conducted for 2 mm, 3 mm, and 4 mm gap length with 0-2 bars pressure for argon gas. Electrodes of a sparkgap chamber are of rogowsky profile type, made up of stainless steel material, and thickness of 15 mm are used in the recovery study. The variation in the distance and pressure effects the recovery rate of the spark gap. An intermediate plateu is observed in the spark gap recovery curves. Recovery time decreases with increase in pressure and shorter gaps in length are recovering faster than longer gaps.

A Investigation of the Verbal Description of Trombone Tone Quality with Respect to Selected Attributes of Sound

NASA Astrophysics Data System (ADS)

Stroeher, Michael Steven

The purpose of this study was to determine the physical elements which experienced trombonists associate with selected descriptors in characterizing the tone quality of that instrument. Stimuli sampled from live trombone tones and synthesized into musical phrases represented 17 variations in (1) presence/absence of attack transient, (2) rise time, (3) duration, (4) number of harmonics, (5) upper limit of harmonicity, (6) spectral envelope shape, and (7) frequency. A vocabulary of 20 adjectives appropriate for describing trombone tone quality was established by a postal survey of 49 college trombone instructors. A pretest was presented to 28 University of North Texas trombone students, who rated the 17 stimuli in terms of the 20 adjectives on a Likert-type scale with reliability estimates of.8997 to.9439 (coefficient alpha). The pretest established the lack of significance of the attack transient in subjects' descriptions. Factor analysis of responses determined similarities in word usages and allowed the number of descriptors to be reduced to eight and the number of sound stimuli to nine for the final investigation. Subjects of the final study consisted of 161 trombonists at universities in Texas, Oklahoma, Colorado, Michigan and North Carolina, who rated the nine stimuli in terms of the eight chosen adjectives on Likert-type scales, with an overall reliability estimate of.7121 (coefficient alpha). Although the low reliability indicated some lack of agreement in descriptor usage, multiple regression analysis established relationships among subjects' use of descriptors and physical attributes of the stimuli. Subjects' judgements of bright were associated with tones of higher frequency; centered, good, dark and warm with faster rise time, longer duration and relatively fewer harmonics; pinched with a high number of harmonics and slower rise time; fuzzy with slow rise time and the presence of high-frequency inharmonic noise. Subjects did not use the word full with any degree of consistency.

Comparison of fast electric field changes from subsequent return strokes of natural and triggered lightning

NASA Technical Reports Server (NTRS)

Le Vine, D. M.; Willett, J. C.; Bailey, J. C.

1989-01-01

Fast electric field changes from subsequent return strokes of natural and triggered lightning with propagation paths almost entirely over water are compared. Data were collected at the Kennedy Space Center, Florida, during the summer of 1987. Comparisons have been made of the average shape, the risetime, and the spectrum of the electric field changes. To a first approximation, the waveforms are very similar; however, the electric field changes from the triggered flashes tend to rise to peak faster and decay faster than do their counterparts in natural cloud-to-ground flashes.

Windowed Green function method for the Helmholtz equation in the presence of multiply layered media

NASA Astrophysics Data System (ADS)

Bruno, O. P.; Pérez-Arancibia, C.

2017-06-01

This paper presents a new methodology for the solution of problems of two- and three-dimensional acoustic scattering (and, in particular, two-dimensional electromagnetic scattering) by obstacles and defects in the presence of an arbitrary number of penetrable layers. Relying on the use of certain slow-rise windowing functions, the proposed windowed Green function approach efficiently evaluates oscillatory integrals over unbounded domains, with high accuracy, without recourse to the highly expensive Sommerfeld integrals that have typically been used to account for the effect of underlying planar multilayer structures. The proposed methodology, whose theoretical basis was presented in the recent contribution (Bruno et al. 2016 SIAM J. Appl. Math. 76, 1871-1898. (doi:10.1137/15M1033782)), is fast, accurate, flexible and easy to implement. Our numerical experiments demonstrate that the numerical errors resulting from the proposed approach decrease faster than any negative power of the window size. In a number of examples considered in this paper, the proposed method is up to thousands of times faster, for a given accuracy, than corresponding methods based on the use of Sommerfeld integrals.

Windowed Green function method for the Helmholtz equation in the presence of multiply layered media.

PubMed

Bruno, O P; Pérez-Arancibia, C

2017-06-01

This paper presents a new methodology for the solution of problems of two- and three-dimensional acoustic scattering (and, in particular, two-dimensional electromagnetic scattering) by obstacles and defects in the presence of an arbitrary number of penetrable layers. Relying on the use of certain slow-rise windowing functions, the proposed windowed Green function approach efficiently evaluates oscillatory integrals over unbounded domains, with high accuracy, without recourse to the highly expensive Sommerfeld integrals that have typically been used to account for the effect of underlying planar multilayer structures. The proposed methodology, whose theoretical basis was presented in the recent contribution (Bruno et al. 2016 SIAM J. Appl. Math. 76 , 1871-1898. (doi:10.1137/15M1033782)), is fast, accurate, flexible and easy to implement. Our numerical experiments demonstrate that the numerical errors resulting from the proposed approach decrease faster than any negative power of the window size. In a number of examples considered in this paper, the proposed method is up to thousands of times faster, for a given accuracy, than corresponding methods based on the use of Sommerfeld integrals.

Real-time blind image deconvolution based on coordinated framework of FPGA and DSP

NASA Astrophysics Data System (ADS)

Wang, Ze; Li, Hang; Zhou, Hua; Liu, Hongjun

2015-10-01

Image restoration takes a crucial place in several important application domains. With the increasing of computation requirement as the algorithms become much more complexity, there has been a significant rise in the need for accelerating implementation. In this paper, we focus on an efficient real-time image processing system for blind iterative deconvolution method by means of the Richardson-Lucy (R-L) algorithm. We study the characteristics of algorithm, and an image restoration processing system based on the coordinated framework of FPGA and DSP (CoFD) is presented. Single precision floating-point processing units with small-scale cascade and special FFT/IFFT processing modules are adopted to guarantee the accuracy of the processing. Finally, Comparing experiments are done. The system could process a blurred image of 128×128 pixels within 32 milliseconds, and is up to three or four times faster than the traditional multi-DSPs systems.

The dynamics of synchronized neurotransmitter release determined from compound spontaneous IPSCs in rat dentate granule neurones in vitro

PubMed Central

Williams, Stephen R; Buhl, Eberhard H; Mody, Istvan

1998-01-01

The properties of GABAA receptor-mediated spontaneous IPSCs generated in hippocampal dentate granule neurones were analysed using whole-cell voltage-clamp techniques in order to explore the functional consequences of the low number (6–12) and close proximity of synaptic contacts made by single GABAergic interneurones. Spontaneous IPSCs (sIPSCs) occurred with a frequency of 14.0 ± 9.1 Hz (n = 31) and revealed a multi-modal positively skewed amplitude distribution (39.0 ± 19.8 pA, median values). The variance of 10–90 % rise times and decay kinetics between IPSCs decreased with increasing peak amplitude. Larger amplitude events had significantly faster rise times, consistent with their site of generation being proximal to the soma. The decay kinetics of sIPSCs did not significantly change with amplitude. Large amplitude sIPSCs occurred singularly or in discrete bursts, repeated regularly at low frequency. The rising phase of such sIPSCs were multi-phasic, composed of clear step-like inflections that were not a product of noise. The variability between the rising phase of individual sIPSCs was quantified by calculating their standard deviation, which produced fast rising (0.22 ± 0.05 ms time to peak, n = 16) functions with half-widths of 0.38 ± 0.10 ms, which declined to plateaux. Computer simulations demonstrated that IPSCs with properties similar to those recorded experimentally could be generated by the linear summation of groups of temporally dispersed component events. Standard deviation functions of the rising phase of simulated IPSCs accurately described distributions of the temporal dispersion of unitary components. The GABA uptake inhibitor (R)-N-[4,4-bis(3-methyl-2-thienyl)but-3-enl-yl] nipecotic acid (tiagabine) (10 μM, n = 12) significantly prolonged the decay of mIPSCs (6.5 ± 0.8 to 8.7 ± 1.0 ms, median values) and sIPSCs (6.2 ± 0.4 to 7.3 ± 1.2 ms, median values), but failed to alter the frequency of occurrence, 10–90 % rise times or peak amplitude of events. The application of flurazepam (30 μM, n = 7; 50 μM, n = 4) prolonged the decay of sIPSCs regardless of their amplitude. These data indicate that sIPSCs are formed by the summation of unitary components that occur asynchronously and that GABA released from multiple sites has independent postsynaptic actions. PMID:9705998

Informing Biological Design by Integration of Systems and Synthetic Biology

PubMed Central

Smolke, Christina D.; Silver, Pamela A.

2011-01-01

Synthetic biology aims to make the engineering of biology faster and more predictable. In contrast, systems biology focuses on the interaction of myriad components and how these give rise to the dynamic and complex behavior of biological systems. Here, we examine the synergies between these two fields. PMID:21414477

Let's Get Fiscal

ERIC Educational Resources Information Center

Barbour, Andrew

2013-01-01

With the US economy continuing its weak recovery, it's tempting to think that IT budgets in higher education might begin to rebound especially in light of the increased focus on online learning. Nice thought, but no. Education costs are rising even faster than those for healthcare, and the public outcry over the cost of higher education…

Varietal Variability for Cotton Ginning Efficiency

USDA-ARS?s Scientific Manuscript database

Energy consumption is one of the largest expenses of a cotton gin. In light of the rising cost of energy, all avenues should be exploited to optimize energy use in modern cotton gins. One option is to study genetic variability within the available germplasm to look for varieties that gin faster and ...

The Climate Science Special Report: Rising Seas and Changing Oceans

NASA Astrophysics Data System (ADS)

Kopp, R. E.

2017-12-01

GMSL has risen by about 16-21 cm since 1900. Ocean heat content has increased at all depths since the 1960s, and global mean sea-surface temperature increased 0.7°C/century between 1900 to 2016. Human activity contributed substantially to generating a rate of GMSL rise since 1900 faster than during any preceding century in at least 2800 years. A new set of six sea-level rise scenarios, spanning a range from 30 cm to 250 cm of 21st century GMSL rise, were developed for the CSSR. The lower scenario is based on linearly extrapolating the past two decades' rate of rise. The upper scenario is informed by literature estimates of maximum physically plausible values, observations indicating the onset of marine ice sheet instability in parts of West Antarctica, and modeling of ice-cliff and ice-shelf instability mechanisms. The new scenarios include localized projections along US coastlines. There is significant variability around the US, with rates of rise likely greater than GMSL rise in the US Northeast and the western Gulf of Mexico. Under scenarios involving extreme Antarctic contributions, regional rise would be greater than GMSL rise along almost all US coastlines. Historical sea-level rise has already driven a 5- to 10-fold increase in minor tidal flooding in several US coastal cities since the 1960s. Under the CSSR's Intermediate sea-level rise scenario (1.0 m of GMSL rise in 2100) , a majority of NOAA tide gauge locations will by 2040 experience the historical 5-year coastal flood about 5 times per year. Ocean changes are not limited to rising sea levels. Ocean pH is decreasing at a rate that may be unparalleled in the last 66 million years. Along coastlines, ocean acidification can be enhanced by changes in the upwelling (particularly along the US Pacific Coast); by episodic, climate change-enhanced increases in freshwater input (particularly along the US Atlantic Coast); and by the enhancement of biological respiration by nutrient runoff. Climate models project a slowdown in the Atlantic Meridional Overturning Circulation (AMOC) under high-emissions scenarios. Any slowdown will reduce ocean heat and carbon absorption and raise sea levels off the northeastern US A full AMOC collapse, improbable in the current century, would lead to an additional 0.5 m of sea-level rise and offset 0-2°C of warming over the US.

National trends in the cost of employer health insurance coverage, 2003-2013.

PubMed

Collins, Sara R; Radley, David C; Schoen, Cathy; Beutel, Sophie

2014-12-01

Looking at trends in private employer-based health insurance from 2003 to 2013, this issue brief finds that premiums for family coverage increased 73 percent over the past decade--faster than median family income. Employees' contributions to their premiums climbed by 93 percent over that time frame. At the same time, deductibles more than doubled in both large and small firms. Workers are thus paying more but getting less protective benefits. However, the study also finds that while premiums continued to rise through 2013, the rate of growth slowed between 2010 and 2013, following implementation of the Affordable Care Act. While families experienced slower growth in premium contributions and deductibles over this period, sluggish growth in median family income means families are paying more in premiums and deductibles as a share of their income than ever before.

Factors affecting energy deposition and expansion in single wire low current experiments

NASA Astrophysics Data System (ADS)

Duselis, Peter U.; Vaughan, Jeffrey A.; Kusse, Bruce R.

2004-08-01

Single wire experiments were performed on a low current pulse generator at Cornell University. A 220 nF capacitor charged to 15-25 kV was used to drive single wire experiments. The capacitor and wire holder were connected in series through an external variable inductor to control the current rise rate. This external series inductance was adjustable from 0.2 to 2 μH. When coupled with the range of charging voltages this results in current rise rates from 5 to 50 A/ns. The current heated the wire through liquid and vapor phases until plasma formed around the wire. Energy deposition and expansion rates were measured as functions of the current rise rate. These results indicated better energy deposition and higher expansion rates with faster current rise rates. Effects of the wire-electrode connection method and wire polarity were also studied.

Variability of Thermosphere and Ionosphere Responses to Solar Flares

NASA Technical Reports Server (NTRS)

Qian, Liying; Burns, Alan G.; Chamberlin, Philip C.; Solomon, Stanley C.

2011-01-01

We investigated how the rise rate and decay rate of solar flares affect the thermosphere and ionosphere responses to them. Model simulations and data analysis were conducted for two flares of similar magnitude (X6.2 and X5.4) that had the same location on the solar limb, but the X6.2 flare had longer rise and decay times. Simulated total electron content (TEC) enhancements from the X6.2 and X5.4 flares were 6 total electron content units (TECU) and approximately 2 TECU, and the simulated neutral density enhancements were approximately 15% -20% and approximately 5%, respectively, in reasonable agreement with observations. Additional model simulations showed that for idealized flares with the same magnitude and location, the thermosphere and ionosphere responses changed significantly as a function of rise and decay rates. The Neupert Effect, which predicts that a faster flare rise rate leads to a larger EUV enhancement during the impulsive phase, caused a larger maximum ion production enhancement. In addition, model simulations showed that increased E x B plasma transport due to conductivity increases during the flares caused a significant equatorial anomaly feature in the electron density enhancement in the F region but a relatively weaker equatorial anomaly feature in TEC enhancement, owing to dominant contributions by photochemical production and loss processes. The latitude dependence of the thermosphere response correlated well with the solar zenith angle effect, whereas the latitude dependence of the ionosphere response was more complex, owing to plasma transport and the winter anomaly.

Measurement of Effective Drift Velocities of Electrons and Holes in Shallow Multiple Quantum Well P-I Modulators

NASA Astrophysics Data System (ADS)

Yang, Ching-Mei

1995-01-01

P-i-n diodes containing multiple quantum wells (MQWs) in the i-region are the building blocks for photonic devices. When we apply electric field across these devices and illuminate it with light, photo-carriers are created in the i-region. These carriers escape from the wells and drift toward the electrodes; thus photo-voltage is created. The rise- and decay-times of photo-voltages are related to the transport of carriers. In this dissertation, we present theoretical and experimental studies on carrier transport mechanisms of three shallow MQW GaAs/Al _{x}Ga_{1-x}As p-i-n diodes (x = 0.02, 0.04, 0.08) at various bias voltages. We start with the description of the sample structures and their package. We then present the characteristics of these samples including their transmission spectra and responsivity. We will demonstrate that the over-all high quality of these samples, including a strong exciton resonant absorption, ~100% internal quantum efficiencies and completely depleted i-region at bias between +0.75 V to -5 V bias. In our theoretical studies, we first discuss the possible carrier sweep-out mechanisms and estimate the response times associated with these mechanisms. Based on our theoretical model, we conclude that only the drift times of carriers and enhanced diffusion times are important for shallow MQW p-i-n diodes: at high bias, the fast drift times of electrons and holes control the rise-times; at low bias, the slow drift times of holes and the enhanced diffusion times control the decay-times. We have performed picosecond time-resolved pump/probe electro-absorption measurements on these samples. We then obtained the drift times, effective drift velocities and effective mobilities of electrons and holes for these devices. We find that the carrier effective drift velocities (especially for holes) seemed insensitive to the Al concentration in the barriers (in the range of x = 2% to 8%), even though the x = 2% sample does show an overall faster response time. We think the slight difference of the rise- and decay-times of these devices may also be affected by random differences between the samples.

AP Geography, Environmental Science Thrive

ERIC Educational Resources Information Center

Robelen, Erik W.

2012-01-01

Geography may not be particularly known as a hot topic among today's students--even some advocates suggest it suffers from an image problem--but by at least one measure, the subject is starting to come into its own. Across more than 30 topics covered in the Advanced Placement (AP) program, participation in geography is rising faster than any…

Evaluation of the SunWise School Program

ERIC Educational Resources Information Center

Geller, Alan; Rutsch, Linda; Kenausis, Kristin; Zhang, Zi

2003-01-01

Melanoma, the most fatal form of skin cancer, is rising at rates faster than all other preventable cancers in the United States. Childhood exposure to ultraviolet (UV) light increases the risk for skin cancer as an adult, therefore, starting positive sun protection habits early may be key to reducing the incidence of this disease. The…

Forecasting College Costs through 1988-89. American Council on Education Policy Brief.

ERIC Educational Resources Information Center

Henderson, Cathy

Major factors causing tuition and other charges to rise faster than inflation are analyzed. Attention is directed to the effect of inflation on faculty salaries, federal need-based aid to private colleges, expenditures for capital equipment by state colleges, and state appropriations to higher education. Data are provided on average undergraduate…

The Liverpool Connection: Transatlantic Newspapers in the 1840s.

ERIC Educational Resources Information Center

Schwarzlose, Richard A.

The introduction of steam-powered ocean navigation in 1838 made possible the faster delivery of foreign news to United States newspaper offices and also gave rise to a new journalism genre--the transatlantic newspaper. Published on one side of the Atlantic and shipped by steamer for consumption on the other side, transatlantic newspapers compiled…

The Ivory Tower Under Siege.

ERIC Educational Resources Information Center

Smith-Mello, Michal

Increasing public dissatisfaction with the cost and quality of higher education is creating pressure for fundamental change. Higher education is not as certain to produce a higher standard of living as it used to be, and costs are rising faster than the rate of inflation. Declining state contributions to higher education have shifted the financial…

Implications of the radio and X-ray emission that followed GW170817

NASA Astrophysics Data System (ADS)

Nakar, Ehud; Piran, Tsvi

2018-07-01

The radio and X-rays that followed GW170817 increased gradually over ˜100 d, resembling the radio flare predicted to arise from the interaction of a binary neutron star merger outflow with the interstellar medium (Nakar & Piran 2011). Considering a blast wave moving with a Lorentz factor Γ, we show that an off-axis observer, namely an observer at θobs > 1/Γ, sees a light curve rising faster than Fν ∝ t3. Therefore, the observed rise, Fν ∝ t0.78, implies that at all times we have seen an on-axis emission. Nfamely, the emitting matter was within θobs< 1/Γ at the time of observations (even if it was off-axis beforehand). The observations tightly constrain the blast wave Lorentz factor: Γ ˜ (1.5-7)(t/10 d)-0.21. The isotropic equivalent energy in the observed region increases with time, Eiso ˜ 1050 erg(t/150 d)1.3, implying that the outflow was structured. This structure could have different origins; however, the only physically motivated one, proposed so far, is the interaction of a relativistic jet with the ejecta and the resulting cocoon. The jet could have been choked or successful. In the latter case, it has produced a short gamma-ray burst pointing elsewhere (this successful jet-cocoon system is sometimes called a `structured jet'). Although circumstantial evidence disfavours a successful jet, the jet fate cannot be decisively determined from current observations. The light curve alone may not be sufficient to resolve this question, since both chocked and successful jets can lead to a gradual rise to a peak, followed by a decay. Therefore, the recent turnover of the light curve does not necessitate a successful jet.

Implications of the radio and X-ray emission that followed GW170817

NASA Astrophysics Data System (ADS)

Nakar, Ehud; Piran, Tsvi

2018-04-01

The radio and X-rays that followed GW170817 increased gradually over ˜ 100 days, resembling the radio flare predicted to arise from the interaction of a binary neutron star merger outflow with the ISM (Nakar & Piran 2011). Considering a blast wave moving with a Lorentz factor Γ, we show that an off-axis observer, namely an observer at θobs > 1/Γ, sees a light curve rising faster than Fν∝t3. Therefore, the observed rise, Fν∝ t0.78, implies that at all times we have seen an on-axis emission. Namely, the emitting matter was within θobs < 1/Γ at the time of observations (even if it was off-axis beforehand). The observations tightly constrain the blast wave Lorentz factor: Γ ˜ (1.5 - 7)(t/10 day)-0.21. The isotropic equivalent energy in the observed region increases with time, Eiso ˜ 1050 erg (t/150 day)1.3, implying that the outflow was structured. This structure could have different origins, however, the only physically motivated one, proposed so far, is the interaction of a relativistic jet with the ejecta and the resulting cocoon. The jet could have been choked or successful. In the latter case, it has produced a short GRB pointing elsewhere (this successful jet-cocoon system is sometimes called a "structured jet"). Although circumstantial evidence disfavors a successful jet, the jet fate cannot be decisively determined from current observations. The light curve alone may not be sufficient to resolve this question, since both chocked and successful jets can lead to a gradual rise to a peak, followed by a decay. Therefore, the recent turnover of the light curve does not necessitate a successful jet.

Lightning Return-Stroke Current Waveforms Aloft, From Measured Field Change, Current, and Channel Geometry

NASA Technical Reports Server (NTRS)

Willett, J. C.; LeVine, D. M.

2002-01-01

Direct current measurements are available near the attachment point from both natural cloud-to-ground lightning and rocket-triggered lightning, but little is known about the rise time and peak amplitude of return-stroke currents aloft. We present, as functions of height, current amplitudes, rise times, and effective propagation velocities that have been estimated with a novel remote-sensing technique from data on 24 subsequent return strokes in six different lightning flashes that were triggering at the NASA Kennedy Space Center, FL, during 1987. The unique feature of this data set is the stereo pairs of still photographs, from which three-dimensional channel geometries were determined previously. This has permitted us to calculate the fine structure of the electric-field-change (E) waveforms produced by these strokes, using the current waveforms measured at the channel base together with physically reasonable assumptions about the current distributions aloft. The computed waveforms have been compared with observed E waveforms from the same strokes, and our assumptions have been adjusted to maximize agreement. In spite of the non-uniqueness of solutions derived by this technique, several conclusions seem inescapable: 1) The effective propagation speed of the current up the channel is usually significantly (but not unreasonably) faster than the two-dimensional velocity measured by a streak camera for 14 of these strokes. 2) Given the deduced propagation speed, the peak amplitude of the current waveform often must decrease dramatically with height to prevent the electric field from being over-predicted. 3) The rise time of the current wave front must always increase rapidly with height in order to keep the fine structure of the calculated field consistent with the observations.

optGpSampler: an improved tool for uniformly sampling the solution-space of genome-scale metabolic networks.

PubMed

Megchelenbrink, Wout; Huynen, Martijn; Marchiori, Elena

2014-01-01

Constraint-based models of metabolic networks are typically underdetermined, because they contain more reactions than metabolites. Therefore the solutions to this system do not consist of unique flux rates for each reaction, but rather a space of possible flux rates. By uniformly sampling this space, an estimated probability distribution for each reaction's flux in the network can be obtained. However, sampling a high dimensional network is time-consuming. Furthermore, the constraints imposed on the network give rise to an irregularly shaped solution space. Therefore more tailored, efficient sampling methods are needed. We propose an efficient sampling algorithm (called optGpSampler), which implements the Artificial Centering Hit-and-Run algorithm in a different manner than the sampling algorithm implemented in the COBRA Toolbox for metabolic network analysis, here called gpSampler. Results of extensive experiments on different genome-scale metabolic networks show that optGpSampler is up to 40 times faster than gpSampler. Application of existing convergence diagnostics on small network reconstructions indicate that optGpSampler converges roughly ten times faster than gpSampler towards similar sampling distributions. For networks of higher dimension (i.e. containing more than 500 reactions), we observed significantly better convergence of optGpSampler and a large deviation between the samples generated by the two algorithms. optGpSampler for Matlab and Python is available for non-commercial use at: http://cs.ru.nl/~wmegchel/optGpSampler/.

The association of maternal factors with delayed implantation and the initial rise of urinary human chorionic gonadotrophin

PubMed Central

Jukic, A.M.Z.; Weinberg, C.R.; Baird, D.D.; Wilcox, A.J.

2011-01-01

BACKGROUND Late implantation and the pattern of early rise in hCG have been associated with early pregnancy loss. We explored factors that might be predictive of these markers of poor embryonic health in spontaneously conceived pregnancies. METHODS Participants in the North Carolina Early Pregnancy Study collected daily first-morning urine specimens while attempting to conceive. Samples were assayed for estrogen and progesterone metabolites (to identify day of ovulation) and hCG (to detect conception). Data were available for 190 pregnancies, 48 of which ended in early loss (within 6 weeks of the last menstrual period). We used logistic regression to identify characteristics associated with late implantation (≥10 days post-ovulation). For pregnancies surviving at least 6 weeks (n= 142), we used linear mixed models to identify factors associated with variations in hCG rise in the first 7 days from detection. RESULTS Later implantation was associated with current maternal smoking [odds ratio (OR): 5.7; 95% confidence interval (CI): 1.1–30] and with oocytes that were likely to have been fertilized late in their post-ovulatory lifespan (OR: 5.1; CI: 1.9–16). Older women had a faster rise in hCG (P= 0.01), as did women who had relatively late menarche (P for trend = 0.02). Women exposed in utero to diethylstilbestrol showed an unusual pattern of slow initial hCG rise followed by a fast increase, a pattern significantly different from that of unexposed women (P= 0.002). CONCLUSIONS Although limited by small numbers and infrequent exposures, our analyses suggest that a woman's exposures both early in life and at the time of pregnancy may influence early development of the conceptus. PMID:21292636

Partial protection from organophosphate-induced cholinesterase inhibition by metyrapone treatment.

PubMed

Swiercz, Radosław; Lutz, Piotr; Gralewicz, Sławomir; Grzelińska, Zofia; Piasecka-Zelga, Joanna; Wąsowicz, Wojciech

2013-08-01

Organophosphates are cholinesterase (ChE) inhibitors with worldwide use as insecticides. Stress response, evidenced by a dramatic and relatively long-lasting (several hours) rise in the plasma glucocorticoid concentration is an integral element of the organophosphate (OP) poisoning symptomatology. In rodents, corticosterone (CORT) is the main glucocorticoid. There are several reports suggesting a relationship between the stressor-induced rise in CORT concentration (the CORT response) and the activity of the cerebral and peripheral ChE. Thus, it seems reasonable to presume that, in OP intoxication, the rise in plasma CORT concentration may somehow affect the magnitude of the OP-induced ChE inhibition. Metyrapone (MET) [2-methyl-1,2-di(pyridin-3-yl)propan-1-one] blocks CORT synthesis by inhibiting steroid 11β-hydroxylase, thereby preventing the CORT response. Chlorfenvinphos (CVP) [2-chloro-1-(2,4-dichlorophenyl) ethenyl diethyl phosphate] is an organophosphate insecticide still in use in some countries. The purpose of the present work was to compare the CVP-induced effects - the rise of the plasma CORT concentration and the reduction in ChE activity - in MET-treated and MET-untreated rats. Chlorfenvinphos was administered once at 0.0, 0.5, 1.0 and 3.0 mg/kg i.p. Metyrapone, at 100 mg/kg i.p., was administered five times, at 24-h intervals. The first MET dose was given two hours before CVP. The following was observed in the MET-treated rats: i) no rise in plasma CORT concentration after the CVP administration, ii) a reduced inhibition and a faster restitution of blood and brain ChE activities. The results suggest that MET treatment may confer significant protection against at least some effects of OP poisoning. The likely mechanism of the protective MET action has been discussed.

State Funds for Colleges Continue to Rebound

ERIC Educational Resources Information Center

Schmidt, Peter

2006-01-01

This article reports on a new national survey showing that state spending on higher education is continuing to rise throughout most of the nation and growing faster in much of the South. Total state general-fund appropriations for higher education are up by 7 percent, to $72.18-billion, in the current 2006-2007 fiscal year, according to an annual…

Student-Created Fund Helps Raise Money to Cover Unmet Need

ERIC Educational Resources Information Center

Simmons, Cody

2010-01-01

Today's fast-paced and Internet-driven society provides a lot of opportunities for innovation in the college financial aid world. As tuition costs continue to rise faster than average incomes, more students are turning to private lenders and other third-party organizations to finance their educations. While the power of online micro-giving has…

Informing biological design by integration of systems and synthetic biology.

PubMed

Smolke, Christina D; Silver, Pamela A

2011-03-18

Synthetic biology aims to make the engineering of biology faster and more predictable. In contrast, systems biology focuses on the interaction of myriad components and how these give rise to the dynamic and complex behavior of biological systems. Here, we examine the synergies between these two fields. Copyright © 2011 Elsevier Inc. All rights reserved.

Anomalous current diffusion and improved confinement in the HT-6M tohamak

NASA Astrophysics Data System (ADS)

Gao, X.; Li, J. G.; Wan, Y. X.; Huo, Y. P.; Guo, W. K.; Fan, S. P.; Yu, C. X.; Luo, J. R.; Yin, F. X.; Meng, Y. D.; Zheng, L.; Yin, F.; Lin, B. L.; Zhang, S. Y.; Wang, S. Y.; Lu, H. J.; Liu, S. X.; Tong, X. D.; Ding, L. C.; Wu, Z. Y.; Yin, X. J.; Guo, Q. L.; Gong, X. Z.; Wu, X. C.; Zhao, J. Y.; Xi, J. S.

1994-10-01

Current diffusion was studied during edge ohmic heating (EOH) experiments in the HT-6M tokamak. The EOH power system makes the plasma current linearly ramp up from an initial steady state ( Ip=55kA) to a second steady state ( Ip=60kA) at a fast ramp rate of 12 MA/s. A stable discharge of an improved confinement was observed experimentally in the HT-6M tokamak after the plasma current was ramped to rise rapidly to a second steady state. The plasma current is ramped up much faster than both the classical skin time and neoclassical skin time. Fast current ramp up increases the anomalous current diffusion. The measured values of {β P+l i}/{2} and the soft X-ray sawtooth inversion radius imply the anomalous current penetration. The mechanism of anomalous penetration and improved confinement is discussed.

Impact of muscle tension dysphonia on tonal pitch target implementation in vietnamese female teachers.

PubMed

Nguyen, Duong Duy; Kenny, Dianna T

2009-11-01

Muscle tension dysphonia (MTD) is a voice disorder with deteriorated vocal quality, particularly pitch problems. Because pitch is mainly controlled by the laryngeal muscles, and because MTD is characterized by increased laryngeal muscle tension, we hypothesized that it may result in problems in pitch target implementation in tonal languages. We examined tonal samples of 42 Vietnamese female primary school teachers diagnosed with MTD and compared them with 30 vocally healthy female teachers who spoke the same dialect. Tonal data were analyzed using Computerized Speech Lab (CSL-4300B) for Windows. From tonal sampling bases, fundamental frequency (F0) was measured at target points specified by contour examination. Parameters representing pitch movement including time, size, and speed of movement were measured for the falling tone and rising tone. We found that F0 at target points in MTD group was lowered in most tones, especially tones with extensive F0 variation. In MTD group, target F0 of the broken tone in isolation was 37.5 Hz lower (P<0.01) and target F0 of rising tone in isolation was 46 Hz lower (P<0.01) than in control group. In MTD group, speed of pitch fall of the falling tone in isolation was faster than control group by 2.2 semitones/second (st/s) (P<0.05) and speed of pitch rise in the rising tone in isolation was slower than control group by 7.2 st/s (P<0.01). These results demonstrate that MTD is associated with problems in tonal pitch variation.

Fluorescence resonance energy transfer in microemulsions composed of tripled-chain surface active ionic liquids, RTILs, and biological solvent: an excitation wavelength dependence study.

PubMed

Banerjee, Chiranjib; Kundu, Niloy; Ghosh, Surajit; Mandal, Sarthak; Kuchlyan, Jagannath; Sarkar, Nilmoni

2013-08-15

In this article we have reported the fluorescence resonance energy transfer (FRET) study in our earlier characterized surface active ionic liquids (SAILs)-containing microemulsion, i.e., N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([P13][Tf2N])/[CTA][AOT]/isopropyl myristate ([IPM]) and N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide ([N3111][Tf2N])/[CTA][AOT]/[IPM] microemulsions (Banerjee, C.; Mandal, S.; Ghosh, S.; Kuchlyan, J.; Kundu, N.; Sarkar, N. J. Phys. Chem. B 2013, 117, 3927-3934). The occurrence of effective FRET from the donor, coumarin-153 (C-153) to the acceptor rhodamine 6G (R6G) is evident from the decrease in the steady state fluorescence intensity of the donor with addition of acceptor and subsequent increase in the fluorescence intensity of the acceptor in the presence of donor. The excitation wavelength dependent FRET from C-153 to R6G has also been performed to assess the dynamic heterogeneity of these confined systems. In time-resolved experiments, the significant rise time of the acceptor in the presence of the donor further confirms the occurrence of FRET. The multiple donor-acceptor (D-A) distances, for various microemulsions, obtained from the rise times of the acceptor emission in the presence of a donor can be rationalized from the varying distribution of the donor, C-153, in the different regions of the microemulsion. Time-resolved measurement reveals that with increasing excitation wavelength from 408 to 440 nm, the contribution of the faster rise component of FRET increases significantly due to the close proximity of the C-153 and R6G in the polar region of the microemulsion where occurrence of FRET is very high. Moreover, we have also studied the FRET with variation of R (R = [room temperature ionic liquids (RTILs)]/[surfactant]) and shown that the effect of excitation wavelength on FRET is similar irrespective of R values.

Managing Private College Finances in an Environment in Which Spending and Revenues Grow at Different Rates

ERIC Educational Resources Information Center

Kaufman, Roger T.; Woglom, Geoffrey

2008-01-01

Recently, spending and fees at colleges and universities have been rising faster than family incomes. If this trend persists, increasing emphasis will be placed on endowments as a source of finance. This paper examines financial planning when growth rates for the sources and uses of funds differ. First, we examine concepts of "intergenerational…

Where Does All That Tuition Go? Education Outlook. No. 12

ERIC Educational Resources Information Center

Schneider, Mark

2009-01-01

As any parent with a college-bound child knows, college tuitions are rising much faster than inflation. One way to control costs is to make parents better consumers by giving them better price and outcome information. But the true cost of a college education is hard to calculate because of complex and opaque pricing structures. Today, colleges are…

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

White, D.B.

This paper reports on experiments to examine gas migration rates in drilling muds that were performed in a 15-m-long, 200-mm-ID inclinable flow loop where air injection simulates gas entry during a kick. These tests were conducted using a xanthum gum (a common polymer used in drilling fluids) solution to simulate drilling muds as the liquid phase and air as the gas phase. This work represents a significant extension of existing correlations for gas/liquid flows in large pipe diameters with non- Newtonian fluids. Bubbles rise faster in drilling muds than in water despite the increased viscosity. This surprising result is causedmore » by the change in the flow regime, with large slug-type bubbles forming at lower void fractions. The gas velocity is independent of void fraction, thus simplifying flow modeling. Results show that a gas influx will rise faster in a well than previously believed. This has major implications for kick simulation, with gas arriving at the surface earlier than would be expected and the gas outflow rate being higher than would have been predicted. A model of the two-phase gas flow in drilling mud, including the results of this work, has been incorporated into the joint Schlumberger Cambridge Research (SCR)/BP Intl. kick model.« less

National health expenditure projections, 2013-23: faster growth expected with expanded coverage and improving economy.

PubMed

Sisko, Andrea M; Keehan, Sean P; Cuckler, Gigi A; Madison, Andrew J; Smith, Sheila D; Wolfe, Christian J; Stone, Devin A; Lizonitz, Joseph M; Poisal, John A

2014-10-01

In 2013 health spending growth is expected to have remained slow, at 3.6 percent, as a result of the sluggish economic recovery, the effects of sequestration, and continued increases in private health insurance cost-sharing requirements. The combined effects of the Affordable Care Act's coverage expansions, faster economic growth, and population aging are expected to fuel health spending growth this year and thereafter (5.6 percent in 2014 and 6.0 percent per year for 2015-23). However, the average rate of increase through 2023 is projected to be slower than the 7.2 percent average growth experienced during 1990-2008. Because health spending is projected to grow 1.1 percentage points faster than the average economic growth during 2013-23, the health share of the gross domestic product is expected to rise from 17.2 percent in 2012 to 19.3 percent in 2023. Project HOPE—The People-to-People Health Foundation, Inc.

First measurement of the double spin asymmetry in (-->)e(-->)p-->e(prime)pi(+)n in the resonance region.

PubMed

De Vita, R; Anghinolfi, M; Burkert, V D; Dodge, G E; Minehart, R; Taiuti, M; Weller, H; Adams, G; Amaryan, M J; Anciant, E; Armstrong, D S; Asavapibhop, B; Asryan, G; Audit, G; Auger, T; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bianchi, N; Biselli, A S; Boiarinov, S; Bonner, B E; Bosted, P; Bouchigny, S; Branford, D; Brooks, W K; Bueltmann, S; Calarco, J R; Capitani, G P; Carman, D S; Carnahan, B; Cazes, A; Ciciani, L; Cole, P L; Coleman, A; Connelly, J; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; De Sanctis, E; Degtyarenko, P V; Demirchyan, R; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Eckhause, M; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Farhi, L; Fatemi, R; Feuerbach, R J; Ficenec, J; Forest, T A; Frolov, V; Funsten, H; Gaff, S J; Gai, M; Garçon, M; Gavalian, G; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Girard, P; Golovatch, E; Griffioen, K; Guidal, M; Guillo, M; Gyurjyan, V; Hadjidakis, C; Hancock, D; Hardie, J; Heddle, D; Heimberg, P; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hu, J; Hyde-Wright, C E; Ishkanov, B S; Ito, M M; Jenkins, D; Joo, K; Kelley, J H; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Lachniet, J; Laget, J M; Lawrence, D; Li, Ji; Livingston, K; Longhi, A; Loukachine, K; Lucas, M; Major, W; Manak, J J; Marchand, C; McAleer, S; McCarthy, J; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mikhailov, K; Mirazita, M; Miskimen, R; Mokeev, V; Muccifora, V; Mueller, J; Mutchler, G S; Napolitano, J; Nelson, S O; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Opper, A K; O'Rielly, G V; Osipenko, M; Park, K; Pasyuk, E; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Reolon, A R; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Rock, S; Ronchetti, F; Rossi, P; Rowntree, D; Rubin, P D; Sabatié, F; Sabourov, K; Salgado, C; Sapunenko, V; Sargsyan, M; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Skabelin, A V; Smith, E S; Smith, T; Smith, L C; Sober, D I; Sorrell, L; Spraker, M; Stavinsky, A; Stepanyan, S; Stoler, P; Strakovsky, I I; Taylor, S; Tedeschi, D J; Thompson, R; Todor, L; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weisberg, A; Weygand, D P; Whisnant, C S; Wolin, E; Yegneswaran, A; Yun, J; Zhang, B; Zhao, J; Zhou, Z

2002-02-25

The double spin asymmetry in the (-->)e(-->)p --> e(prime)pi(+)n reaction has been measured for the first time in the resonance region for four-momentum transfer Q2 = 0.35-1.5 GeV(2). Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH3 target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with Q(2) of the helicity asymmetry A1 for the F(15)(1680) resonance than expected from the analysis of the unpolarized data.

Faster than the Speed of Hearing: Nanomechanical Force Probes Enable the Electromechanical Observation of Cochlear Hair Cells

PubMed Central

Doll, Joseph C.; Peng, Anthony W.; Ricci, Anthony J.; Pruitt, Beth L.

2012-01-01

Understanding the mechanisms responsible for our sense of hearing requires new tools for unprecedented stimulation and monitoring of sensory cell mechanotransduction at frequencies yet to be explored. We describe nanomechanical force probes designed to evoke mechanotransduction currents at up to 100kHz in living cells. High-speed force and displacement metrology is enabled by integrating piezoresistive sensors and piezoelectric actuators onto nanoscale cantilevers. The design, fabrication process, actuator performance and actuator-sensor crosstalk compensation results are presented. We demonstrate the measurement of mammalian cochlear hair cell mechanotransduction with simultaneous patch clamp recordings at unprecedented speeds. The probes can deliver mechanical stimuli with sub-10 μs rise times in water and are compatible with standard upright and inverted microscopes. PMID:23181721

Symmetric and asymmetric instability of buried polymer interfaces

NASA Astrophysics Data System (ADS)

de Silva, J. P.; Cousin, F.; Wildes, A. R.; Geoghegan, M.; Sferrazza, M.

2012-09-01

We demonstrate using neutron reflectometry that the internal interfaces in a trilayer system of two identical thick polystyrene layers sandwiching a much thinner (deuterated) poly(methyl methacrylate) layer 15 nm thick (viscosity matched with the polystyrene layers) increase in roughness at the same rate. When the lower polystyrene layer is replaced with a layer of the same polymer of much greater molecular mass, two different growths of the interfaces are observed. From the growth of the interface for this asymmetric case in the solid regime using the theoretical prediction of the spinodal instability including slippage at the interface, a value of the Hamaker constant of the system has been extracted in agreement with the calculated value. For the symmetric case the rise time of the instability is much faster.

National health expenditure projections, 2014-24: spending growth faster than recent trends.

PubMed

Keehan, Sean P; Cuckler, Gigi A; Sisko, Andrea M; Madison, Andrew J; Smith, Sheila D; Stone, Devin A; Poisal, John A; Wolfe, Christian J; Lizonitz, Joseph M

2015-08-01

Health spending growth in the United States is projected to average 5.8 percent for 2014-24, reflecting the Affordable Care Act's coverage expansions, faster economic growth, and population aging. Recent historically low growth rates in the use of medical goods and services, as well as medical prices, are expected to gradually increase. However, in part because of the impact of continued cost-sharing increases that are anticipated among health plans, the acceleration of these growth rates is expected to be modest. The health share of US gross domestic product is projected to rise from 17.4 percent in 2013 to 19.6 percent in 2024. Project HOPE—The People-to-People Health Foundation, Inc.

Eye coding mechanisms in early human face event-related potentials.

PubMed

Rousselet, Guillaume A; Ince, Robin A A; van Rijsbergen, Nicola J; Schyns, Philippe G

2014-11-10

In humans, the N170 event-related potential (ERP) is an integrated measure of cortical activity that varies in amplitude and latency across trials. Researchers often conjecture that N170 variations reflect cortical mechanisms of stimulus coding for recognition. Here, to settle the conjecture and understand cortical information processing mechanisms, we unraveled the coding function of N170 latency and amplitude variations in possibly the simplest socially important natural visual task: face detection. On each experimental trial, 16 observers saw face and noise pictures sparsely sampled with small Gaussian apertures. Reverse-correlation methods coupled with information theory revealed that the presence of the eye specifically covaries with behavioral and neural measurements: the left eye strongly modulates reaction times and lateral electrodes represent mainly the presence of the contralateral eye during the rising part of the N170, with maximum sensitivity before the N170 peak. Furthermore, single-trial N170 latencies code more about the presence of the contralateral eye than N170 amplitudes and early latencies are associated with faster reaction times. The absence of these effects in control images that did not contain a face refutes alternative accounts based on retinal biases or allocation of attention to the eye location on the face. We conclude that the rising part of the N170, roughly 120-170 ms post-stimulus, is a critical time-window in human face processing mechanisms, reflecting predominantly, in a face detection task, the encoding of a single feature: the contralateral eye. © 2014 ARVO.

The role of varying flow on channel morphology: a flume experiment

NASA Astrophysics Data System (ADS)

Hempel, L. A.; Grant, G.; Eaton, B. C.; Hassan, M. A.; Lewis, S.

2017-12-01

Numerous studies have explored how alluvial channels develop under different sediment and flow conditions, yet we still know very little about how channels adjust and respond to changing flow conditions. One reason for this oversight is the long-held idea that channels with complex flow regimes are adjusted to a single, channel-forming discharge. But growing evidence shows that channel form reflects time-dependent processes occuring over multiple flows. To better understand how stream channels adjust to a range of flows, and identify the timescales associated with those adjustments, we conducted a series of hydrograph experiments in a freely-adjustable flume that developed a self-formed, meander pattern with pool-riffle morphology. Hydrographs had different shapes, magnitudes, and durations, but the total sediment volume fed under equilibrium conditions was kept constant among experiments. We found that hydrograph shape controlled channel morphology, the rate of channel development, and degree of regularity in the pool-riffle pattern. Hydrographs with slowly rising rates of rise and fall produced channels that were equivalent in size to channels generated from constant flow experiments, and had regularly spaced pool-riffle and meander patterns, while hydrographs with fast rates of rise and fall produced undersized channels with a chaotic bed structure and pool-riffle pattern. The latter suggests that during quickly rising hydrographs, the flow rate increases faster than the channel capacity and planform pattern adjusts. We confirmed these observations by comparing the timescales associated with pool-riffle and planform curvature development, which were identified under simple, constant flow conditions, to the total duration of the hydrograph. Hydrographs with step durations equal to or longer than the channel adjustment time produced channels with a more regular pool-riffle patterns compared to channels with step durations shorter than the adjustment time. This work points to the importance of the hydrograph as a fundamental control on channel adjustment and offers the prospect of better understanding of how changes in the flow regime, either through climate, land use, or dams, translate into morphodynamic changes.

Comparative study of all-printed polyimide humidity sensors with single- and multiwalled carbon nanotube gas-permeable top electrodes

NASA Astrophysics Data System (ADS)

Itoh, Eiji; Yuan, Zihan

2017-05-01

We have developed printed capacitive humidity sensors with highly gas permeable carbon nanotube top electrodes using solution techniques. The hydrophobic, porous multiwalled carbon nanotube (MWCNT) network was suitable for gas permeation, and the response of the capacitive humidity sensors was faster than that of a device with a single-walled carbon nanotube (SWCNT) top electrode. The newly developed measurement system consisting of a small measurement chamber, a computer-controlled high-speed solenoid valve, and a mass-flow controller enabled us to vary the ambient relative humidity within 0.1 s. A comparative study of the devices consisting of a 1.1-µm-thick partially fluorinated polyimide dielectric layer and an MWCNT or SWCNT top electrode revealed that the rise time (humidification process) of the device with MWCNTs (0.49 s) in the transient measurement was almost 3 times shorter than that with SWCNTs (1.48 s) owing to the hydrophobic surface of the MWCNTs. A much larger difference was observed during the drying process (recovery time) probably owing to the hydrophilic parts of the SWCNT surface. It was revealed that the response time was almost proportional to the square of the thickness of the polyimide dielectric layer, d, and the sensitivity was inversely proportional to d. The rise time decreased to 0.15 s and a sensitivity per unit area of 12.1 pF %RH-1 cm-2 was obtained in a device with 0.6-µm-thick polyimide and MWCNT top electrodes. This value is suitable for use in high-speed humidity sensors to realize a real-time humidity and breath-sensing measurement system.

How to reduce out-of-pocket costs for prescription medications.

PubMed

Eliason, Mark J; Sontheimer, Richard D

2015-06-16

The cost of prescription medicines has recently been rising faster than other healthcare costs.  This is also true for traditionally inexpensive generic medications that have long served as a fundamental healthcare safety net in the USA.  These changes increasingly present challenges for individuals to obtain common medications.  Owing to rising insurance co-pays, even patients who have prescription medication insurance coverage are beginning to experience challenges in this area.  This document was created to help patients and their families consider various strategies and programs that exist in 2015 for reducing their out-of-pocket costs for their prescription medications.  We believe that this information can also be helpful to healthcare providers when counseling patients about managing rapidly rising prescription drug costs.  An effort has been made to make this document readable to patients and their families as well as to healthcare providers.

Driving technology for improving motion quality of active-matrix organic light-emitting diode display

NASA Astrophysics Data System (ADS)

Kim, Jongbin; Kim, Minkoo; Kim, Jong-Man; Kim, Seung-Ryeol; Lee, Seung-Woo

2014-09-01

This paper reports transient response characteristics of active-matrix organic light emitting diode (AMOLED) displays for mobile applications. This work reports that the rising responses look like saw-tooth waveform and are not always faster than those of liquid crystal displays. Thus, a driving technology is proposed to improve the rising transient responses of AMOLED based on the overdrive (OD) technology. We modified the OD technology by combining it with a dithering method because the conventional OD method cannot successfully enhance all the rising responses. Our method can improve all the transitions of AMOLED without modifying the conventional gamma architecture of drivers. A new artifact is found when OD is applied to certain transitions. We propose an optimum OD selection method to mitigate the artifact. The implementation results show the proposed technology can successfully improve motion quality of scrolling texts as well as moving pictures in AMOLED displays.

Evidence that the Na+-K+ leak/pump ratio contributes to the difference in endurance between fast- and slow-twitch muscles.

PubMed

Clausen, T; Overgaard, K; Nielsen, O B

2004-02-01

Muscles containing predominantly fast-twitch (type II) fibres [ext. dig. longus (EDL)] show considerably lower contractile endurance than muscles containing mainly slow-twitch (type I) fibres (soleus). To assess whether differences in Na+-K+ fluxes and excitability might contribute to this phenomenon, we compared excitation-induced Na+-K+ leaks, Na+ channels, Na+-K+ pump capacity, force and compound action potentials (M-waves) in rat EDL and soleus muscles. Isolated muscles were mounted for isometric contractions in Krebs-Ringer bicarbonate buffer and exposed to direct or indirect continuous or intermittent electrical stimulation. The time-course of force decline and concomitant changes in Na+-K+ exchange and M-waves were recorded. During continuous stimulation at 60-120 Hz, EDL showed around fivefold faster rate of force decline than soleus. This was associated with a faster loss of excitability as estimated from the area and amplitude of the M-waves. The net uptake of Na+ and the release of K+ per action potential were respectively 6.5- and 6.6-fold larger in EDL than in soleus, which may in part be due to the larger content of Na+ channels in EDL. During intermittent stimulation with 1 s 60 Hz pulse trains, EDL showed eightfold faster rate of force decline than soleus. The considerably lower contractile endurance of fast-twitch compared with slow-twitch muscles reflects differences in the rate of excitation-induced loss of excitability. This is attributed to the much larger excitation-induced Na+ influx and K+ efflux, leading to a faster rise in [K+]o in fast-twitch muscles. This may only be partly compensated by the concomitant activation of the Na+-K+ pumps, in particular in fibres showing large passive Na+-K+ leaks or reduced content of Na+-K+ pumps. Thus, endurance depends on the leak/pump ratio for Na+ and K+.

The Fast and Non-capillary Fluid Filling Mechanism in the Hummingbird's Tongue

NASA Astrophysics Data System (ADS)

Rico-Guevara, Alejandro; Fan, Tai-Hsi; Rubega, Margaret

2014-03-01

Hummingbirds gather nectar by inserting their beaks inside flowers and cycling their tongues at a frequency of up to 20 Hz. It is unclear how they achieve efficiency at this high licking rate. Ever since proposed in 1833, it has been believed that hummingbird tongues are a pair of tiny straws filled with nectar by capillary rise. Our discoveries are very different from this general consensus. The tongue does not draw up floral nectar via capillary action under experimental conditions that resemble natural ones. Theoretical models based on capillary rise were mistaken and unsuitable for estimating the fluid intake rate and to support foraging theories. We filmed (up to 1265 frames/s) the fluid uptake in 20 species of hummingbirds that belong to 7 out of the 9 main hummingbird clades. We found that the fluid filling within the portions of the tongue that remain outside the nectar is about five times faster than capillary filling. We present strong evidence to rule out the capillarity model. We introduce a new fluid-structure interaction and hydrodynamic model and compare the results with field experimental data to explain how hummingbirds actually extract fluid from flowers at the lick level.

College Costs and Family Income: The Affordability Issue at UC and CSU. Report 11-02

ERIC Educational Resources Information Center

Jones, Jessika

2011-01-01

Rising costs are putting an education at California's public universities out of reach for many Californians. Eroding state funding for higher education has meant that more costs are passed on to students and their families in the form of increased fees. Room and board and other costs have grown much faster than inflation. Incomes have not kept…

Student Aid Is up, but the Rise in College Costs Outpaces Family Incomes

ERIC Educational Resources Information Center

Supiano, Beckie

2008-01-01

College prices rose only slightly faster than inflation for the 2008-2009 academic year, but that may say more about the American economy's steeper prices for everything than it does about college costs. Tuition and fees rose between 4.5 percent and 6.5 percent for various types of institutions, similar to previous years, but a 5.6-percent…

How Cultural Capital, Habitus, and Social Capital Impacts Pell-Eligible Vermont Students in Navigating the Financial Systems of Higher Education

ERIC Educational Resources Information Center

De Freitas, Xavier

2017-01-01

With the US recovering from a recession, a college diploma has become more valuable to avoid unemployment. Despite a college degree's importance, the access to higher education is a challenge for lower income Pell-Eligible Vermont students. For the past three decades, higher education continues to rise in cost faster than family income. Cost is…

Periodic matrix models for seasonal dynamics of structured populations with application to a seabird population.

PubMed

Cushing, J M; Henson, Shandelle M

2018-02-03

For structured populations with an annual breeding season, life-stage interactions and behavioral tactics may occur on a faster time scale than that of population dynamics. Motivated by recent field studies of the effect of rising sea surface temperature (SST) on within-breeding-season behaviors in colonial seabirds, we formulate and analyze a general class of discrete-time matrix models designed to account for changes in behavioral tactics within the breeding season and their dynamic consequences at the population level across breeding seasons. As a specific example, we focus on egg cannibalism and the daily reproductive synchrony observed in seabirds. Using the model, we investigate circumstances under which these life history tactics can be beneficial or non-beneficial at the population level in light of the expected continued rise in SST. Using bifurcation theoretic techniques, we study the nature of non-extinction, seasonal cycles as a function of environmental resource availability as they are created upon destabilization of the extinction state. Of particular interest are backward bifurcations in that they typically create strong Allee effects in population models which, in turn, lead to the benefit of possible (initial condition dependent) survival in adverse environments. We find that positive density effects (component Allee effects) due to increased adult survival from cannibalism and the propensity of females to synchronize daily egg laying can produce a strong Allee effect due to a backward bifurcation.

Nuisance Flooding and Relative Sea-Level Rise: the Importance of Present-Day Land Motion.

PubMed

Karegar, Makan A; Dixon, Timothy H; Malservisi, Rocco; Kusche, Jürgen; Engelhart, Simon E

2017-09-11

Sea-level rise is beginning to cause increased inundation of many low-lying coastal areas. While most of Earth's coastal areas are at risk, areas that will be affected first are characterized by several additional factors. These include regional oceanographic and meteorological effects and/or land subsidence that cause relative sea level to rise faster than the global average. For catastrophic coastal flooding, when wind-driven storm surge inundates large areas, the relative contribution of sea-level rise to the frequency of these events is difficult to evaluate. For small scale "nuisance flooding," often associated with high tides, recent increases in frequency are more clearly linked to sea-level rise and global warming. While both types of flooding are likely to increase in the future, only nuisance flooding is an early indicator of areas that will eventually experience increased catastrophic flooding and land loss. Here we assess the frequency and location of nuisance flooding along the eastern seaboard of North America. We show that vertical land motion induced by recent anthropogenic activity and glacial isostatic adjustment are contributing factors for increased nuisance flooding. Our results have implications for flood susceptibility, forecasting and mitigation, including management of groundwater extraction from coastal aquifers.

Ecosystem engineers drive creek formation in salt marshes.

PubMed

Vu, Huy D; Wie Ski, Kazimierz; Pennings, Steven C

2017-01-01

Ecosystem engineers affect different organisms and processes in multiple ways at different spatial scales. Moreover, similar species may differ in their engineering effects for reasons that are not always clear. We examined the role of four species of burrowing crabs (Sesarma reticulatum, Eurytium limosum, Panopeus herbstii, Uca pugnax) in engineering tidal creek networks in salt marshes experiencing sea level rise. In the field, crab burrows were associated with heads of eroding creeks and the loss of plant (Spartina alterniflora) stems. S. reticulatum was closely associated with creek heads, but densities of the other crab species did not vary across marsh zones. In mesocosm experiments, S. reticulatum excavated the most soil and strongly reduced S. alterniflora biomass. The other three species excavated less and did not affect S. alterniflora. Creek heads with vegetation removed to simulate crab herbivory grew significantly faster than controls. Percolation rates of water into marsh sediments were 10 times faster at creek heads than on the marsh platform. Biomass decomposed two times faster at creek heads than on the marsh platform. Our results indicate that S. reticulatum increases creek growth by excavating sediments and by consuming plants, thereby increasing water flow and erosion at creek heads. Moreover, it is possible that S. reticulatum burrows also increase creek growth by increasing surface and subsurface erosion, and by increasing decomposition of organic matter at creek heads. Our results show that the interaction between crab and plant ecosystem engineers can have both positive and negative effects. At a small scale, in contrast to other marsh crabs, S. reticulatum harms rather than benefits plants, and increases erosion rather than marsh growth. At a large scale, however, S. reticulatum facilitates the drainage efficiency of the marsh through the expansion of tidal creek networks, and promotes marsh health. © 2016 by the Ecological Society of America.

Plane wave density functional molecular dynamics study of exothermic reactions of Al/CuO thermites

NASA Astrophysics Data System (ADS)

Oloriegbe, Suleiman; Sewell, Thomas; Chen, Zhen; Jiang, Shan; Gan, Yong

2014-03-01

Exothermic reactions between nanosize aluminum (Al) and copper oxide (CuO) structures are of current interest because of their high reaction enthalpy and energy density which exceed those of traditional monomolecular energetic compounds such as TNT, RDX, and HMX. In this work, molecular dynamics simulations with forces obtained from plane wave density functional theory are used to investigate the atomic-scale and electronic processes that occur during the fast thermite reactions between Al and CuO nanostructures under adiabatic conditions. Aluminum surfaces in contact with O-exposed and Cu-exposed CuO surfaces are studied. Starting from initial temperature T = 800 K, we have observed: faster chemical reaction at the oxygen-rich interface during the initial 0.5 ps, linear temperature rise, and fast oxygen diffusion into the Al region with the rate 1.87 X 10-3 cm2/s. The density-derived electrostatic and chemical method is used to evaluate the net atomic charges and charge transfer during the important redox processes. High charge density around the oxygen-exposed interface may be responsible for the faster initial reactions at that interface. The overall reaction rate, determined using the time evolution of Cu-O charge orbital overlap population, is approximately first order.

Permian Minimum and the Following Major Rise in Seawater 87Sr/86Sr Linked to the Glaciation/Deglaciation and Resultant Change in Weathering Rate

NASA Astrophysics Data System (ADS)

Kani, T.; Isozaki, Y.

2014-12-01

We report a detailed secular change of the middle Middle to early Late Permian seawater 87Sr/86Sr ratio for and Akasaka and Kamura carbonates (Japan) deposited on mid-Pansalassan seamounts and for Shizipo carbonates (South China) deposited on the shallow marine shelf. In these coeval sections, extremely low values (<0.7069; the lowest values of the Phanerozoic) continued from upper Wordian (middle Middle Permian) to the topmost Capitanian (upper Middle Permian) barren interval immediately below the Middle-Late Permian boundary characterized by the major crisis of large-tested fusulines and rugose corals. Immediately after ca. 5 m.y.-long minimum interval, the major rise in 87Sr/86Sr was started and the rate of the rise (0.00007/m.y.) continued in period of time containing 21 m.y. until early Triassic (~239 Ma), that is faster than the Cenozoic major rise (0.00003/m.y.).　The most significant shift through Phanerozoic in Sr isotope trend can be explained by the remarkable changes in continental erosion/weathering rate; in particular, by the onset of glaciation and the following deglaciation, that is supported by global sea level change, in addition to the initial doming/rifting of Pangea. After the Capitanian cooling, the long-term climatic regime shifted to a warmer one during which inland ice sheet was removed to expose old crustal silicates for to erosion/weathering. A mantle plume impingiment might lead a domal uplift that accelerate weathering. Highly radiogenic continental Sr could enter the ocean along the new drainage systems developed with the rifting.

Fast Dynamic Simulation-Based Small Signal Stability Assessment and Control

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

Acharya, Naresh; Baone, Chaitanya; Veda, Santosh

2014-12-31

Power grid planning and operation decisions are made based on simulation of the dynamic behavior of the system. Enabling substantial energy savings while increasing the reliability of the aging North American power grid through improved utilization of existing transmission assets hinges on the adoption of wide-area measurement systems (WAMS) for power system stabilization. However, adoption of WAMS alone will not suffice if the power system is to reach its full entitlement in stability and reliability. It is necessary to enhance predictability with "faster than real-time" dynamic simulations that will enable the dynamic stability margins, proactive real-time control, and improve gridmore » resiliency to fast time-scale phenomena such as cascading network failures. Present-day dynamic simulations are performed only during offline planning studies, considering only worst case conditions such as summer peak, winter peak days, etc. With widespread deployment of renewable generation, controllable loads, energy storage devices and plug-in hybrid electric vehicles expected in the near future and greater integration of cyber infrastructure (communications, computation and control), monitoring and controlling the dynamic performance of the grid in real-time would become increasingly important. The state-of-the-art dynamic simulation tools have limited computational speed and are not suitable for real-time applications, given the large set of contingency conditions to be evaluated. These tools are optimized for best performance of single-processor computers, but the simulation is still several times slower than real-time due to its computational complexity. With recent significant advances in numerical methods and computational hardware, the expectations have been rising towards more efficient and faster techniques to be implemented in power system simulators. This is a natural expectation, given that the core solution algorithms of most commercial simulators were developed decades ago, when High Performance Computing (HPC) resources were not commonly available.« less

Linkages of periodic climatic and social-economic changes in China during the past 2000 years

NASA Astrophysics Data System (ADS)

Fang, Xiuqi; Su, Yu; Yin, Jun; Wei, Zhudeng

2016-04-01

Impacts of climate change on rise and fall of human civilization in the history could provide lessons for understanding how impacts of climatic change and human response interacted. However, such a study is highly restricted by lacking in high-resolution series concerning long-term social-economic processes. China is a country that has great potential for providing long-term socio-economic series in high-resolution because it has abundant related historical records as long as thousands of years in the Chinese historical literatures. In this paper, A methodology named Semantic Differential for quantifying historical literal descriptions to grade numbers is developed. Using the methodology, 10-year resolution graded series of social-economic system change of China, including harvest of agriculture, economy, social rise and fall, are reconstructed during the past 2000 years. To compare the periodic changes of climate, harvest, economy, social rise and fall in China during the past 2000 years, it is found that : (1) There are similar periods on multiple time scales among all the series. (2) On the centurial scale, the better economic and social phases generally occurred in the better harvest phases when generally had a warm climate. (3) In the warm phases, both economic and social status were recovered faster and flourished longer than that in the cold phases. (4) The direct impact of climatic change on food security could be enlarged or diminished when it transmitted from harvest I to other social-economic subsystems because of feedbacks of the system.

Changing Course - the Baird Team Solution: a Delta for All

NASA Astrophysics Data System (ADS)

Nairn, R. B.

2016-02-01

The Changing Course Design competition was initiated to evaluate options for re-positioning the mouth of the Mississippi River and modifying the management of the Lower Mississippi River to support the 2017 Master Plan for the Louisiana coast. This paper will present the findings of one of the selected competitors: the Baird Team and their "Delta for All" approach. A key to success in the future management of the lower Mississippi River is the development of an integrated, holistic approach to management that recognizes the need to harness the full land/wetland building and restorative potential of the river at the same time as improving flood protection and navigation. Fundamentally the Baird solution recognized the underlying geomorphic challenges of the Delta: it receives three to four times less sediment from the Mississippi River than it did historically and sea level is rising two to three times faster than it did historically and is predicted to rise much faster in the future. The result will be a smaller delta in the future. Our approach seeks to harness as close to 100% of the land building potential of the river to make the smaller future delta as large as possible. This compares to the 2012 State Master Plan which would harness approximately 50% of the land-building potential. Our approach also recognizes that the further inland new distributary mouths and associated sub-deltas are located, the greater the delta building potential. Our approach builds with the river by creating and managing new river distributaries that are opened and closed every 50 years or so to build new sub-deltas within a defined sustainable delta footprint. By placing the last outlet somewhere in the vicinity of English Turn the lower Mississippi River would become a tidal channel. These two simple concepts of harnessing 100% of the river and placing the last outlet near English Turn result in immediate and significant benefits for flood protection and navigation. Through the elements of our approach the level of flood protection for New Orleans and surrounding areas would be increased from a 1/100 year to approximately 1/1000 year level. By making the lower river a tidal channel, costly future maintenance dredging costs for a 50 ft navigation channel would be mostly eliminated and expansion of navigation and shipping facilities would be possible.

Speed on the dance floor: Auditory and visual cues for musical tempo.

PubMed

London, Justin; Burger, Birgitta; Thompson, Marc; Toiviainen, Petri

2016-02-01

Musical tempo is most strongly associated with the rate of the beat or "tactus," which may be defined as the most prominent rhythmic periodicity present in the music, typically in a range of 1.67-2 Hz. However, other factors such as rhythmic density, mean rhythmic inter-onset interval, metrical (accentual) structure, and rhythmic complexity can affect perceived tempo (Drake, Gros, & Penel, 1999; London, 2011 Drake, Gros, & Penel, 1999; London, 2011). Visual information can also give rise to a perceived beat/tempo (Iversen, et al., 2015), and auditory and visual temporal cues can interact and mutually influence each other (Soto-Faraco & Kingstone, 2004; Spence, 2015). A five-part experiment was performed to assess the integration of auditory and visual information in judgments of musical tempo. Participants rated the speed of six classic R&B songs on a seven point scale while observing an animated figure dancing to them. Participants were presented with original and time-stretched (±5%) versions of each song in audio-only, audio+video (A+V), and video-only conditions. In some videos the animations were of spontaneous movements to the different time-stretched versions of each song, and in other videos the animations were of "vigorous" versus "relaxed" interpretations of the same auditory stimulus. Two main results were observed. First, in all conditions with audio, even though participants were able to correctly rank the original vs. time-stretched versions of each song, a song-specific tempo-anchoring effect was observed, such that sped-up versions of slower songs were judged to be faster than slowed-down versions of faster songs, even when their objective beat rates were the same. Second, when viewing a vigorous dancing figure in the A+V condition, participants gave faster tempo ratings than from the audio alone or when viewing the same audio with a relaxed dancing figure. The implications of this illusory tempo percept for cross-modal sensory integration and working memory are discussed, and an "energistic" account of tempo perception is proposed. Copyright © 2015 Elsevier B.V. All rights reserved.

Ghost forest creation and the conversion of uplands to wetlands

NASA Astrophysics Data System (ADS)

Kirwan, M. L.; Schieder, N. W.; Reay, W.

2017-12-01

Global sea level rise rates began accelerating sharply in the late 19th century, with an approximate tripling in sea level rise rates in many regions of the world. Some portions of the coastal landscape, such as marshes and barrier islands, survive relative sea level rise by natural eco-geomorphic processes that allow them to build elevation vertically and migrate landward. In contrast, adjacent uplands typically occupied by forests and agricultural fields have limited ability to resist the impacts of sea level rise. This portion of the coastal landscape consists of mostly salt intolerant plants, receives little mineral sediment deposition, and rarely builds elevation through the accumulation of soil organic matter. Thus, ghost forests- dead trees surrounded by marshland- are a prominent feature of many low-relief coastal landscapes, and represent a striking visual indicator of upland to wetland conversion. Here, we report preliminary results of several efforts designed to quantify rates and drivers of upland to wetland conversion in the mid-Atlantic region of the United States. Drone based canopy monitoring and ground-based seedling experiments suggest that ghost forests are created by episodic, storm-driven adult tree mortality paired with continuous seedling mortality. Preliminary comparisons between sediment cores and historical photographs from 5 sites in Maryland, Virginia, and North Carolina suggest that modern coastal forest retreat is 2-10 times faster than late-Holocene retreat rates, and that rates have accelerated in most decades since the 1930's. Finally, historical T-Sheet maps suggest that approximately 100,000 acres (400 km2) of uplands have converted to wetlands in the Chesapeake region, and that about 1/3 of all present-day marsh was created by upland drowning since the late 19th Century. Together, these observations indicate rapid coastal transgression, where low-relief, terrestrial portions of the coastal landscape are perhaps more sensitive to sea level rise than better studied, more seaward portions.

On the Relation Between Spotless Days and the Sunspot Cycle

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2005-01-01

Spotless days are examined as a predictor for the size and timing of a sunspot cycle. For cycles 16-23 the first spotless day for a new cycle, which occurs during the decline of the old cycle, is found to precede minimum amplitude for the new cycle by about approximately equal to 34 mo, having a range of 25-40 mo. Reports indicate that the first spotless day for cycle 24 occurred in January 2004, suggesting that minimum amplitude for cycle 24 should be expected before April 2007, probably sometime during the latter half of 2006. If true, then cycle 23 will be classified as a cycle of shorter period, inferring further that cycle 24 likely will be a cycle of larger than average minimum and maximum amplitudes and faster than average rise, peaking sometime in 2010.

Spatial distribution of unidirectional trends in temperature and temperature extremes in Pakistan

NASA Astrophysics Data System (ADS)

Khan, Najeebullah; Shahid, Shamsuddin; Ismail, Tarmizi bin; Wang, Xiao-Jun

2018-06-01

Pakistan is one of the most vulnerable countries of the world to temperature extremes due to its predominant arid climate and geographic location in the fast temperature rising zone. Spatial distribution of the trends in annual and seasonal temperatures and temperature extremes over Pakistan has been assessed in this study. The gauge-based gridded daily temperature data of Berkeley Earth Surface Temperature (BEST) having a spatial resolution of 1° × 1° was used for the assessment of trends over the period 1960-2013 using modified Mann-Kendall test (MMK), which can discriminate the multi-decadal oscillatory variations from secular trends. The results show an increase in the annual average of daily maximum and minimum temperatures in 92 and 99% area of Pakistan respectively at 95% level of confidence. The annual temperature is increasing faster in southern high-temperature region compared to other parts of the country. The minimum temperature is rising faster (0.17-0.37 °C/decade) compared to maximum temperature (0.17-0.29 °C/decade) and therefore declination of diurnal temperature range (DTR) (- 0.15 to - 0.08 °C/decade) in some regions. The annual numbers of both hot and cold days are increasing in whole Pakistan except in the northern sub-Himalayan region. Heat waves are on the rise, especially in the hot Sindh plains and the Southern coastal region, while the cold waves are becoming lesser in the northern cold region. Obtained results contradict with the findings of previous studies on temperature trends, which indicate the need for reassessment of climatic trends in Pakistan using the MMK test to understand the anthropogenic impacts of climate change.

Near-membrane [Ca2+] transients resolved using the Ca2+ indicator FFP18.

PubMed

Etter, E F; Minta, A; Poenie, M; Fay, F S

1996-05-28

(Ca2+)-sensitive processes at cell membranes involved in contraction, secretion, and neurotransmitter release are activated in situ or in vitro by Ca2+ concentrations ([Ca2+]) 10-100 times higher than [Ca2+] measured during stimulation in intact cells. This paradox might be explained if the local [Ca2+] at the cell membrane is very different from that in the rest of the cell. Soluble Ca2+ indicators, which indicate spatially averaged cytoplasmic [Ca2+], cannot resolve these localized, near-membrane [Ca2+] signals. FFP18, the newest Ca2+ indicator designed to selectively monitor near-membrane [Ca2+], has a lower Ca2+ affinity and is more water soluble than previously used membrane-associating Ca2+ indicators. Images of the intracellular distribution of FFP18 show that >65% is located on or near the plasma membrane. [Ca2+] transients recorded using FFP18 during membrane depolarization-induced Ca2+ influx show that near-membrane [Ca2+] rises faster and reaches micromolar levels at early times when the cytoplasmic [Ca2+], recorded using fura-2, has risen to only a few hundred nanomolar. High-speed series of digital images of [Ca2+] show that near-membrane [Ca2+], reported by FFP18, rises within 20 msec, peaks at 50-100 msec, and then declines. [Ca2+] reported by fura-2 rose slowly and continuously throughout the time images were acquired. The existence of these large, rapid increases in [Ca2+] directly beneath the surface membrane may explain how numerous (Ca2+)-sensitive membrane processes are activated at times when bulk cytoplasmic [Ca2+] changes are too small to activate them.

Pulse generator with intermediate inductive storage as a lightning simulator

NASA Astrophysics Data System (ADS)

Kovalchuk, B. M.; Kharlov, A. V.; Zherlytsyn, A. A.; Kumpyak, E. V.; Tsoy, N. V.

2016-06-01

Compact transportable generators are required for simulating a lightning current pulse for electrical apparatus testing. A bi-exponential current pulse has to be formed by such a generator (with a current rise time of about two orders of magnitude faster than the damping time). The objective of this study was to develop and investigate a compact pulse generator with intermediate inductive storage and a fuse opening switch as a simulator of lightning discharge. A Marx generator (six stages) with a capacitance of 1 μF and an output voltage of 240 kV was employed as primary storage. In each of the stages, two IK-50/3 (50 kV, 3 μF) capacitors are connected in parallel. The generator inductance is 2 μH. A test bed for the investigations was assembled with this generator. The generator operates without SF6 and without oil in atmospheric air, which is very important in practice. Straight copper wires with adjustable lengths and diameters were used for the electro-explosive opening switch. Tests were made with active-inductive loads (up to 0.1 Ω and up to 6.3 μH). The current rise time is lower than 1200 ns, and the damping time can be varied from 35 to 125 μs, following the definition of standard lightning current pulse in the IEC standard. Moreover, 1D MHD calculations of the fuse explosion were carried out self-consistently with the electric circuit equations, in order to calculate more accurately the load pulse parameters. The calculations agree fairly well with the tests. On the basis of the obtained results, the design of a transportable generator was developed for a lightning simulator with current of 50 kA and a pulse shape corresponding to the IEEE standard.

Diffuse interface simulation of bubble rising process: a comparison of adaptive mesh refinement and arbitrary lagrange-euler methods

NASA Astrophysics Data System (ADS)

Wang, Ye; Cai, Jiejin; Li, Qiong; Yin, Huaqiang; Yang, Xingtuan

2018-06-01

Gas-liquid two phase flow exists in several industrial processes and light-water reactors (LWRs). A diffuse interface based finite element method with two different mesh generation methods namely, the Adaptive Mesh Refinement (AMR) and the Arbitrary Lagrange Euler (ALE) methods is used to model the shape and velocity changes in a rising bubble. Moreover, the calculating speed and mesh generation strategies of AMR and ALE are contrasted. The simulation results agree with the Bhagat's experiments, indicating that both mesh generation methods can simulate the characteristics of bubble accurately. We concluded that: the small bubble rises as elliptical with oscillation, whereas a larger bubble (11 mm > d > 7 mm) rises with a morphology between the elliptical and cap type with a larger oscillation. When the bubble is large (d > 11 mm), it rises up as a cap type, and the amplitude becomes smaller. Moreover, it takes longer to achieve the stable shape from the ellipsoid to the spherical cap type with the increase of the bubble diameter. The results also show that for smaller diameter case, the ALE method uses fewer grids and has a faster calculation speed, but the AMR method can solve the case of a large geometry deformation efficiently.

The US and the FRG in the Third World.

DTIC Science & Technology

1982-06-01

cont.asnt, imports from developed countries were only 0.5% cheaper than American products . This saves U.S. consumers more than $2 billion a year. It is...positive impact on the growth rates of the developed coun- tries. The total demand of the LDCs was important in maintaining the production level of...progress for the less-developed countries: with rapidly rising exports, they collectively increased their real national product such faster than the

Contributions of Dynamic and Thermodynamic Scaling in Subdaily Precipitation Extremes in India

NASA Astrophysics Data System (ADS)

Ali, Haider; Mishra, Vimal

2018-03-01

Despite the importance of subdaily precipitation extremes for urban areas, the role of dynamic and thermodynamic scaling in changes in precipitation extremes in India remains poorly constrained. Here we estimate contributions from thermodynamic and dynamic scaling on changes in subdaily precipitation extremes for 23 urban locations in India. Subdaily precipitation extremes have become more intense during the last few decades. Moreover, we find a twofold rise in the frequency of subdaily precipitation extremes during 1979-2015, which is faster than the increase in daily precipitation extremes. The contribution of dynamic scaling in this rise in the frequency and intensity of subdaily precipitation extremes is higher than the thermodynamic scaling. Moreover, half-hourly precipitation extremes show higher contributions from the both thermodynamic ( 10%/K) and dynamic ( 15%/K) scaling than daily (6%/K and 9%/K, respectively) extremes indicating the role of warming on the rise in the subdaily precipitation extremes in India. Our findings have implications for better understanding the dynamic response of precipitation extremes under the warming climate over India.

Postglacial Fringing-Reef to Barrier-Reef conversion on Tahiti links Darwin's reef types

NASA Astrophysics Data System (ADS)

Blanchon, Paul; Granados-Corea, Marian; Abbey, Elizabeth; Braga, Juan C.; Braithwaite, Colin; Kennedy, David M.; Spencer, Tom; Webster, Jody M.; Woodroffe, Colin D.

2014-05-01

In 1842 Charles Darwin claimed that vertical growth on a subsiding foundation caused fringing reefs to transform into barrier reefs then atolls. Yet historically no transition between reef types has been discovered and they are widely considered to develop independently from antecedent foundations during glacio-eustatic sea-level rise. Here we reconstruct reef development from cores recovered by IODP Expedition 310 to Tahiti, and show that a fringing reef retreated upslope during postglacial sea-level rise and transformed into a barrier reef when it encountered a Pleistocene reef-flat platform. The reef became stranded on the platform edge, creating a lagoon that isolated it from coastal sediment and facilitated a switch to a faster-growing coral assemblage dominated by acroporids. The switch increased the reef's accretion rate, allowing it to keep pace with rising sea level, and transform into a barrier reef. This retreat mechanism not only links Darwin's reef types, but explains the re-occupation of reefs during Pleistocene glacio-eustacy.

Eruption of a plasma blob, associated M-class flare, and large-scale extreme-ultraviolet wave observed by SDO

NASA Astrophysics Data System (ADS)

Kumar, P.; Manoharan, P. K.

2013-05-01

We present a multiwavelength study of the formation and ejection of a plasma blob and associated extreme ultraviolet (EUV) waves in active region (AR) NOAA 11176, observed by SDO/AIA and STEREO on 25 March 2011. The EUV images observed with the AIA instrument clearly show the formation and ejection of a plasma blob from the lower atmosphere of the Sun at ~9 min prior to the onset of the M1.0 flare. This onset of the M-class flare happened at the site of the blob formation, while the blob was rising in a parabolic path with an average speed of ~300 km s. The blob also showed twisting and de-twisting motion in the lower corona, and the blob speed varied from ~10-540 km s. The faster and slower EUV wavefronts were observed in front of the plasma blob during its impulsive acceleration phase. The faster EUV wave propagated with a speed of ~785 to 1020 km s, whereas the slower wavefront speed varied in between ~245 and 465 km s. The timing and speed of the faster wave match the shock speed estimated from the drift rate of the associated type II radio burst. The faster wave experiences a reflection by the nearby AR NOAA 11177. In addition, secondary waves were observed (only in the 171 Å channel), when the primary fast wave and plasma blob impacted the funnel-shaped coronal loops. The Helioseismic Magnetic Imager (HMI) magnetograms revealed the continuous emergence of new magnetic flux along with shear flows at the site of the blob formation. It is inferred that the emergence of twisted magnetic fields in the form of arch-filaments/"anemone-type" loops is the likely cause for the plasma blob formation and associated eruption along with the triggering of M-class flare. Furthermore, the faster EUV wave formed ahead of the blob shows the signature of fast-mode MHD wave, whereas the slower wave seems to be generated by the field line compression by the plasma blob. The secondary wave trains originated from the funnel-shaped loops are probably the fast magnetoacoustic waves. Three movies are available in electronic form at http://www.aanda.org

Revisiting salt marsh resilience to sea level rise: Are ponds responsible for permanent land loss?

NASA Astrophysics Data System (ADS)

Mariotti, G.

2016-12-01

Ponds are un-vegetated rounded depressions commonly present on marsh platforms. The role of ponds on the long-term morphological evolution of tidal marshes is unclear - at times ponds expand but eventually recover the marsh platform, at other times ponds never recover and lead to permanent marsh loss. Existing field observations indicate that episodic disturbances of the marsh vegetation cause the formation of small (1-10 m) isolated ponds, even if the vegetated platform keeps pace with Relative Sea Level Rise (RSLR), and that isolated ponds tend to deepen and enlarge until they eventually connect to the channel network. Here I implement a simple model to study the vertical and planform evolution of a single connected pond. A newly connected pond recovers if its bed lies above the limit for marsh plant growth, or if the inorganic deposition rate is larger than the RSLR rate. A pond that cannot accrete faster than RSLR will deepen and enlarge, eventually entering a runaway erosion by wave edge retreat. A large tidal range, a large sediment supply, and a low rate of RSLR favor pond recovery. The model suggests that inorganic sediment deposition alone controls pond recovery, even in marshes where organic matter dominates accretion of the vegetated platform. As such, halting permanent marsh loss by pond collapse requires to increase inorganic sediment deposition. Because pond collapse is possible even if the vegetated platform keeps pace with RSLR, I conclude that marsh resilience to RSLR is less than previously quantified.

Effects of Cloud-Microphysics on Tropical Atmospheric Hydrologic Processes in the GEOS GCM

NASA Technical Reports Server (NTRS)

Lau, K. M.; Wu, H. T.; Sud, Y. C.; Walker, G. K.

2004-01-01

The sensitivity of tropical atmospheric hydrologic processes to cloud-microphysics is investigated using the NASA GEOS GCM. Results show that a faster autoconversion - rate produces more warm rain and less clouds at all levels. Fewer clouds enhances longwave cooling and reduces shortwave heating in the upper troposphere, while more warm rain produces increased condensation heating in the lower troposphere. This vertical heating differential destablizes the tropical atmosphere, producing a positive feedback resulting in more rain over the tropics. The feedback is maintained via a two-cell secondary circulation. The lower cell is capped by horizontal divergence and maximum cloud detrainment near the melting/freezing, with rising motion in the warm rain region connected to descending motion in the cold rain region. The upper cell is found above the freezing/melting level, with longwave-induced subsidence in the warm rain and dry regions, coupled to forced ascent in the deep convection region. The tropical large scale circulation is found to be very sensitive to the radiative-dynamic effects induced by changes in autoconversion rate. Reduced cloud-radiation processes feedback due to a faster autoconversion rate results in intermittent but more energetic eastward propagating Madden and Julian Oscillations (MJO). Conversely,-a slower autconversion rate, with increased cloud radiation produces MJO's with more realistic westward propagating transients, resembling a supercloud cluster structure. Results suggests that warm rain and associated low and mid level clouds, i.e., cumulus congestus, may play a critical role in regulating the time-intervals of deep convections and hence the fundamental time scales of the MJO.

Rapid temperature increase near the anode and cathode in the afterglow of a pulsed positive streamer discharge

NASA Astrophysics Data System (ADS)

Ono, Ryo

2018-06-01

The spatiotemporal evolution of the temperature in the afterglow of point-to-plane, pulsed positive streamer discharge was measured near the anode tip and cathode surface using laser-induced predissociation fluorescence of OH radicals. The temperature exhibited a rapid increase and displayed a steep spatial gradient after a discharge pulse. The rate of temperature rise reached 84 K μs‑1 at mm, where z represents the distance from the anode tip. The temperature rise was much faster than in the middle of the gap; it was only 2.8 K μs‑1 at mm. The temperature reached 1700 K near the anode tip at s and 1500 K near the cathode surface at s, where t represents the postdischarge time. The spatial gradient reached 1280 K mm‑1 near the anode tip at s. The mechanism responsible for the rapid temperature increase was discussed, including rapid heating of the gas in the early postdischarge phase (s), and vibration-to-translation energy transfer in the later postdischarge phase (s). The high temperatures near the anode tip and cathode surface are particularly important for the ignition of combustible mixtures and for surface treatments, including solid-surface treatments, water treatments, and plasma medicine using pulsed streamer discharges.

Submicrosecond electro-optic switching in the liquid-crystal smectic A phase: The soft-mode ferroelectric effect

NASA Astrophysics Data System (ADS)

Andersson, G.; Dahl, I.; Keller, P.; Kuczyński, W.; Lagerwall, S. T.; Skarp, K.; Stebler, B.

1987-08-01

A new liquid-crystal electro-optic modulating device similar to the surface-stabilized ferroelectric liquid-crystal device is described. It uses the same kind of ferroelectric chiral smectics and the same geometry as that device (thin sample in the ``bookshelf '' layer arrangement) but instead of using a tilted smectic phase like the C* phase, it utilizes the above-lying, nonferroelectric A phase, taking advantage of the electroclinic effect. The achievable optical intensity modulation that can be detected through the full range of the A phase is considerably lower than for the surface-stabilized device, but the response is much faster. Furthermore, the response is strictly linear with respect to the applied electric field. The device concept is thus appropriate for modulator rather than for display applications. We describe the underlying physics and present measurements of induced tilt angle, of light modulation depth, and of rise time.

Influence of insulating coating on aluminum wire explosions

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

Li, Yang; Wu, Jian, E-mail: jxjawj@gmail.com; State Key Laboratory of Intense Pulse Radiation of Simulation and Effect, Northwest Institute of Nuclear Technology, Xi'an 710024

2014-10-15

Single wire explosions are widely used in understanding the early stages of z-pinch experiments. This paper presents a serial of experiments conducted on the pulse power generator with ∼1 kA peak current and ∼10 ns rising time in Xi'an Jiao Tong University. Polyimide coated aluminum wires and uncoated ones were tested under three different voltages to analyze the effect of insulating coating. Experimental results showed that insulating coating can increase the energy deposition 10%∼30% in aluminum wires by delaying the voltage collapse and raising the maximum load resistance. The substantial energy deposition resulted in about 20% faster expansion rates for coated wires.more » Experimental evidence that plasma channel shunts the current from the wire core was observed by streak camera and schlieren graphs. This paper also briefly discussed the influence of nonuniform coating on the morphology of wire expansion.« less

High Performance Molybdenum Disulfide Amorphous Silicon Heterojunction Photodetector

PubMed Central

Esmaeili-Rad, Mohammad R.; Salahuddin, Sayeef

2013-01-01

One important use of layered semiconductors such as molybdenum disulfide (MoS2) could be in making novel heterojunction devices leading to functionalities unachievable using conventional semiconductors. Here we demonstrate a metal-semiconductor-metal heterojunction photodetector, made of MoS2 and amorphous silicon (a-Si), with rise and fall times of about 0.3 ms. The transient response does not show persistent (residual) photoconductivity, unlike conventional a-Si devices where it may last 3–5 ms, thus making this heterojunction roughly 10X faster. A photoresponsivity of 210 mA/W is measured at green light, the wavelength used in commercial imaging systems, which is 2−4X larger than that of a-Si and best reported MoS2 devices. The device could find applications in large area electronics, such as biomedical imaging, where a fast response is critical. PMID:23907598

Canine bombesin-like gastrin releasing peptides stimulate gastrin release and acid secretion in the dog.

PubMed Central

Bunnett, N W; Clark, B; Debas, H T; Del Milton, R C; Kovacs, T O; Orloff, M S; Pappas, T N; Reeve, J R; Rivier, J E; Walsh, J H

1985-01-01

The synthetic mammalian bombesin-like peptides, canine gastrin releasing peptide 27, 23 and 10, and porcine gastrin releasing peptide 27 were compared with amphibian bombesin 14 and 10 during intravenous infusions into six conscious dogs with chronic gastric cannulae. Gastrin and gastrin releasing peptide were measured in peripherally sampled venous blood by radioimmunoassay and gastric acid secretions were collected. All forms of gastrin releasing peptide stimulated gastrin release and gastric acid secretion in a dose-dependent manner. The larger canine and porcine peptides were more potent than the decapeptide. Bombesin 14 was more potent than bombesin 10. A rise in the venous concentration of immunoreactive gastrin releasing peptide of only 20 fmol ml-1 stimulated gastrin release to about 50% of maximal. Gastrin releasing peptide 10 was cleared from the circulation three times faster than the larger forms and this may account for the apparent differences in potency. PMID:3839849

A New Method for Raising Opening Velocity of Electromagnetic Actuated Vacuum Circuit Breaker

NASA Astrophysics Data System (ADS)

Tsukima, Mitsuru; Takeuchi, Toshie; Koyama, Kenichi; Yoshiyasu, Hajimu

Recently an electromagnetic actuator has been widely used as an operating mechanism for the vacuum circuit breaker (VCB). The opening velocity of the contact is supposed to be strongly related with current interruption performance. This paper presents a simple and new technique that raises opening velocity of the electromagnetic actuated VCB. In order to investigate this reason, we built a numerical simulator that predicts the dynamic characteristics of the VCB contact. It takes into account of the magnetic behavior in the actuator and is also coupled with the external control circuit. According to this simulation, it is shown that it is originated from the sharp rise in the electromagnetic thrust force due to the selective saturation of the magnetic yoke. As the result of our experiments, by this technique the opening velocity was verified to be 1.5 times faster than by the conventional way.

Sea level change since 2005: importance of salinity

NASA Astrophysics Data System (ADS)

Llovel, W.; Purkey, S.; Meyssignac, B.; Kolodziejczyk, N.; Blazquez, A.; Bamber, J. L.

2017-12-01

Sea level rise is one of the most important consequences of the actual global warming. Global mean sea level has been rising at a faster rate since 1993 (over the satellite altimetry era) than previous decades. This rise is expected to accelerate over the coming decades and century. At global scale, sea level rise is caused by a combination of freshwater increase from land ice melting and land water changes (mass component) and ocean warming (thermal expansion). Estimating the causes is of great interest not only to understand the past sea level changes but also to validate projections based on climate models. In this study, we investigate the global mass contribution to recent sea level changes with an alternative approach by estimating the global ocean freshening. For that purpose, we consider the unprecedented amount of salinity measurements from Argo floats for the past decade (2005-2015). We compare our results to the ocean mass inferred by GRACE data and based on a sea level budget approach. Our results bring new constrains on the global water cycle (ocean freshening) and energy budget (ocean warming) as well as on the global ocean mass directly inferred from GRACE data.

Geriatric cancer trends in the Middle-East: Findings from Lebanese cancer projections until 2025.

PubMed

Haddad, Fady Gh; Kattan, Joseph; Kourie, Hampig R; El Rassy, Elie; Assi, Tarek; Adib, Salim M

2018-03-01

By 2020, 70% of all cancers will occur in patients aged 65years and older, causing an increase in related morbidity, mortality, and cost. This study projects cancer trends in the elderly population in Lebanon, a country experiencing accelerating aging trends. Findings will guide future policy decisions regarding geriatric oncology in Lebanon and the surrounding Arab world. Cancer incidence rates were derived for men and women 65years and above, divided into three age groups: 65-69years, 70-74years, and 75years and above. Raw data were obtained from the National Cancer Registry reports 2003-2010. The eight consecutive year data were used to project the incidence until 2025 using a logarithmic model. The Average Annual Percent Change in incidence rates was calculated to determine whether it would significantly increase, decrease, or remain stable over time. Incidence rates are projected to increase significantly in all age groups of both genders until 2025. In men, the fastest rise is expected in prostate cancer, followed by bladder, lung, colorectal, and NHL. In women, the rise will be fastest in breast, followed by colorectal, lung, NHL, and ovary. Projected rates increase faster in the "younger" age group 65-69 compared to the "oldest" ≥75, both in men and women. Only kidney and liver cancers continue to rise significantly after 75. Cancer incidence is projected to increase in individuals between 65 and 74years of age. Lebanese and Middle Eastern physicians must implement adapted therapeutic strategies in the management of the increasing caseload among frail, elderly patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structure and Transport Anomalies in Soft Colloids

NASA Astrophysics Data System (ADS)

Srivastava, Samanvaya; Archer, Lynden A.; Narayanan, Suresh

2013-04-01

Anomalous trends in nanoparticle correlation and motion are reported in soft nanoparticle suspensions using static and dynamic x-ray scattering measurements. Contrary to normal expectations, we find that particle-particle correlations decrease and particle dynamics become faster as volume fraction rises above a critical particle loading associated with overlap. Our observations bear many similarities to the cascade of structural and transport anomalies reported for complex, network forming molecular fluids such as water, and are argued to share similar physical origins.

Generalized conjugate-gradient methods for the Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Ajmani, Kumud; Ng, Wing-Fai; Liou, Meng-Sing

1991-01-01

A generalized conjugate-gradient method is used to solve the two-dimensional, compressible Navier-Stokes equations of fluid flow. The equations are discretized with an implicit, upwind finite-volume formulation. Preconditioning techniques are incorporated into the new solver to accelerate convergence of the overall iterative method. The superiority of the new solver is demonstrated by comparisons with a conventional line Gauss-Siedel Relaxation solver. Computational test results for transonic flow (trailing edge flow in a transonic turbine cascade) and hypersonic flow (M = 6.0 shock-on-shock phenoena on a cylindrical leading edge) are presented. When applied to the transonic cascade case, the new solver is 4.4 times faster in terms of number of iterations and 3.1 times faster in terms of CPU time than the Relaxation solver. For the hypersonic shock case, the new solver is 3.0 times faster in terms of number of iterations and 2.2 times faster in terms of CPU time than the Relaxation solver.

Zero-point energy effects in anion solvation shells.

PubMed

Habershon, Scott

2014-05-21

By comparing classical and quantum-mechanical (path-integral-based) molecular simulations of solvated halide anions X(-) [X = F, Cl, Br and I], we identify an ion-specific quantum contribution to anion-water hydrogen-bond dynamics; this effect has not been identified in previous simulation studies. For anions such as fluoride, which strongly bind water molecules in the first solvation shell, quantum simulations exhibit hydrogen-bond dynamics nearly 40% faster than the corresponding classical results, whereas those anions which form a weakly bound solvation shell, such as iodide, exhibit a quantum effect of around 10%. This observation can be rationalized by considering the different zero-point energy (ZPE) of the water vibrational modes in the first solvation shell; for strongly binding anions, the ZPE of bound water molecules is larger, giving rise to faster dynamics in quantum simulations. These results are consistent with experimental investigations of anion-bound water vibrational and reorientational motion.

Effects of employer-sponsored health insurance costs on Social Security taxable wages.

PubMed

Burtless, Gary; Milusheva, Sveta

2013-01-01

The increasing cost of employer contributions for employee health insurance reduces the share of compensation subject to the Social Security payroll tax. Rising insurance contributions can also have a more subtle effect on the Social Security tax base because they influence the distribution of money wages above and below the taxable maximum amount. This article uses the Medical Expenditure Panel Survey to analyze trends in employer health insurance contributions and the distribution of those costs up and down the wage distribution. Our analysis shows that employer health insurance contributions increased faster than overall compensation during 1996-2008, but such contributions grew only slightly faster among workers earning less than the taxable maximum than they did among those earning more. Because employer health insurance contributions represent a much higher percentage of compensation below the taxable maximum, health insurance cost trends exerted a disproportionate downward pressure on money wages below the taxable maximum.

Delayed onset of changes in soma action potential genesis in nociceptive A-beta DRG neurons in vivo in a rat model of osteoarthritis

PubMed Central

Wu, Qi; Henry, James L

2009-01-01

Background Clinical data on osteoarthritis (OA) suggest widespread changes in sensory function that vary during the progression of OA. In previous studies on a surgically-induced animal model of OA we have observed that changes in structure and gene expression follow a variable trajectory over the initial days and weeks. To investigate mechanisms underlying changes in sensory function in this model, the present electrophysiological study compared properties of primary sensory nociceptive neurons at one and two months after model induction with properties in naïve control animals. Pilot data indicated no difference in C- or Aδ-fiber associated neurons and therefore the focus is on Aβ-fiber nociceptive neurons. Results At one month after unilateral derangement of the knee by cutting the anterior cruciate ligament and removing the medial meniscus, the only changes observed in Aβ-fiber dorsal root ganglion (DRG) neurons were in nociceptor-like unresponsive neurons bearing a hump on the repolarization phase; these changes consisted of longer half width, reflecting slowed dynamics of AP genesis, a depolarized Vm and an increased AP amplitude. At two months, changes observed were in Aβ-fiber high threshold mechanoreceptors, which exhibited shorter AP duration at base and half width, shorter rise time and fall time, and faster maximum rising rate/maximum falling rate, reflecting accelerated dynamics of AP genesis. Conclusion These data indicate that Aβ nociceptive neurons undergo significant changes that vary in time and occur later than changes in structure and in nociceptive scores in this surgically induced OA model. Thus, if changes in Aβ-fiber nociceptive neurons in this model reflect a role in OA pain, they may relate to mechanisms underlying pain associated with advanced OA. PMID:19785765

Long-term trends in daily temperature extremes in Iraq

NASA Astrophysics Data System (ADS)

Salman, Saleem A.; Shahid, Shamsuddin; Ismail, Tarmizi; Chung, Eun-Sung; Al-Abadi, Alaa M.

2017-12-01

The existence of long-term persistence (LTP) in hydro-climatic time series can lead to considerable change in significance of trends. Therefore, past findings of climatic trend studies that did not consider LTP became a disputable issue. A study has been conducted to assess the trends in temperature and temperature extremes in Iraq in recent years (1965-2015) using both ordinary Mann-Kendal (MK) test; and the modified Mann-Kendall (m-MK) test, which can differentiate the multi-decadal oscillatory variations from secular trends. Trends in annual and seasonal minimum and maximum temperatures, diurnal temperature range (DTR), and 14 temperature-related extremes were assessed. MK test detected the significant increases in minimum and maximum temperature at all stations, where m-MK test detected at 86% and 80% of all stations, respectively. The temperature in Iraq is increasing 2 to 7 times faster than global temperature rise. The minimum temperature is increasing more (0.48-1.17 °C/decade) than maximum temperature (0.25-1.01 °C/decade). Temperature rise is higher in northern Iraq and in summer. The hot extremes particularly warm nights are increasing all over Iraq at a rate of 2.92-10.69 days/decade, respectively. On the other hand, numbers of cold days are decreasing at some stations at a rate of - 2.65 to - 8.40 days/decade. The use of m-MK test along with MK test confirms the significant increase in temperature and some of the temperature extremes in Iraq. This study suggests that trends in many temperature extremes in the region estimated in previous studies using MK test may be due to natural variability of climate, which empathizes the need for validation of the trends by considering LTP in time series.

Bubble migration in a compacting crystal-liquid mush

NASA Astrophysics Data System (ADS)

Boudreau, Alan

2016-04-01

Recent theoretical models have suggested that bubbles are unlikely to undergo significant migration in a compaction crystal mush by capillary invasion while the system remains partly molten. To test this, experiments of bubble migration during compaction in a crystal-liquid mush were modeled using deformable foam crystals in corn syrup in a volumetric burette, compacted with rods of varying weights. A bubble source was provided by sodium bicarbonate (Alka-Seltzer®). Large bubbles (>several crystal sizes) are pinched by the compacting matrix and become overpressured and deformed as the bubbles experience a load change from hydrostatic to lithostatic. Once they begin to move, they move much faster than the compaction-driven liquid. Bubbles that are about the same size as the crystals but larger than the narrower pore throats move by deformation or breaking into smaller bubbles as they are forced through pore restrictions. Bubbles that are less than the typical pore diameter generally move with the liquid: The liquid + bubble mixture behaves as a single phase with a lower density than the bubble-free liquid, and as a consequence it rises faster than bubble-free liquid and allows for faster compaction. The overpressure required to force a bubble through the matrix (max grain size = 5 mm) is modest, about 5 %, and it is estimated that for a grain size of 1 mm, the required overpressure would be about 25 %. Using apatite distribution in a Stillwater olivine gabbro as an analog for bubble nucleation and growth, it is suggested that relatively large bubbles initially nucleate and grow in liquid-rich channels that develop late in the compaction history. Overpressure from compaction allows bubbles to rise higher into hotter parts of the crystal pile, where they redissolve and increase the volatile content of the liquid over what it would have without the bubble migration, leading to progressively earlier vapor saturation during crystallization of the interstitial liquid. Bubbles can also move rapidly by `surfing' on porosity waves that can develop in a compacting mush.

Implications of pressure diffusion for shock waves

NASA Technical Reports Server (NTRS)

Ram, Ram Bachan

1989-01-01

The report deals with the possible implications of pressure diffusion for shocks in one dimensional traveling waves in an ideal gas. From this new hypothesis all aspects of such shocks can be calculated except shock thickness. Unlike conventional shock theory, the concept of entropy is not needed or used. Our analysis shows that temperature rises near a shock, which is of course an experimental fact; however, it also predicts that very close to a shock, density increases faster than pressure. In other words, a shock itself is cold.

Convergence of shock waves generated by underwater electrical explosion of cylindrical wire arrays between different boundary geometries

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

Yanuka, D.; Zinowits, H. E.; Krasik, Ya. E.

The results of experiments and numerical simulations of a shock wave propagating between either conical or parabolic bounding walls are presented. The shock wave was generated by a microsecond timescale underwater electrical explosion of a cylindrical wire array supplied by a current pulse having an amplitude of ∼230 kA and a rise time of ∼1 μs. It is shown that with the same energy density deposition into the exploding wire array, the shock wave converges faster between parabolic walls, and as a result, the pressure in the vicinity of convergence is ∼2.3 times higher than in the case of conical walls. Themore » results obtained are compared to those of earlier experiments [Antonov et al., Appl. Phys. Lett. 102, 124104 (2013)] with explosions of spherical wire arrays. It is shown that at a distance of ∼400 μm from the implosion origin the pressure obtained in the current experiments is higher than for the case of spherical wire arrays.« less

How Fast? How Far? How Much? What We Need to Learn from the Past Behavior of Ice Sheets, and What They Might Not Tell Us

NASA Astrophysics Data System (ADS)

Alley, R. B.

2016-12-01

Paleoclimatic data support physical understanding that changes in ice sheets are primarily caused by changes in ocean temperature and in melting from above. With interesting qualifications, ice sheets tend to grow as accumulation rate in central regions drops into an ice age, and to shrink as accumulation rate rises. Changes in sea level may be influential but generally are too small and slow to be of primary importance. Thus, future atmospheric warming, oceanic warming and changes in oceanic circulation are especially important to future ice-sheet behavior. Paleoclimatic data support models and physical understanding that sustained warming beyond thresholds will cause progressively larger sea-level rise, up to quite high values, although the thresholds remain poorly quantified. Several indirect lines of evidence indicate great shrinkage or loss of parts or all of the Greenland ice sheet and marine sectors of the Antarctic ice sheet under warmth corresponding to CO2 levels similar to the modern or committed level. Despite this evidence, the state of the ice sheets during the most recent times warmer than today, including MIS 5e, remains unclear. The Greenland ice sheet did survive MIS 5e, but that may reflect warmth sufficient to remove the ice sheet but not sustained long enough to do so; greater warming in the future could cause much faster sea-level rise than generated in the past. Several indirect lines of evidence indicate that the marine basins of the West Antarctic Ice Sheet deglaciated during MIS 5e, and targeted field data could clarify this greatly. Physical understanding suggests, however, that even if this deglaciation did occur, it may have been slower than is possible in an even warmer future world; past rates of sea-level rise may define minimum rather than likely future rates.

Understanding Recent Trends in Freezing Level Height over the Tropical Andes Mountains of South America: An Investigation of Reanalysis Products and GEOSCCM Integrations.

NASA Astrophysics Data System (ADS)

Zaitchik, B. F.; Russell, A.; Gnanadesikan, A.

2015-12-01

As the global climate warms, the height of the 0°C isotherm - aka the freezing level height (FLH) - rises, especially over mountainous regions. Over the past few decades, FLH in the tropical Andes Mountains of South America has been rising at a rate that is 2 to 3 times faster than would be expected considering the zonally-averaged upper troposphere temperature trends and the recent cooling of Pacific Ocean sea surface temperatures. Rising FLH could have devastating impacts in this region where most of the dry season runoff comes from seasonal snow melt and glacial melt. Yet, is unclear why FLH is rising so rapidly in this particular area and what the quantitative implications will be for tropical Andean water resources. Reanalysis products tend to disagree on the spatial pattern and strength of FLH changes which confounds the issue by making it difficult to uncover the driving mechanisms of these local changes in FLH. Indeed, there are several possible factors that may be contributing to the unprecedented rise in FLH over the Andes (above and beyond the normally expected effects of greenhouse gases) of which the most likely actors are: changes in the state of the tropical Pacific Ocean, changes in sea surface temperatures in the Atlantic Ocean, shifts in the Hadley cell, indirect effects of stratospheric ozone depletion and recent recovery, and local thermodynamic land-atmosphere feedbacks. To better understand the changes in FLH, which will ultimately contribute to the effort to predict effects on Andean water resources, we analyze FLH in several forcing-separated integrations of the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). By separating out the various forcings (greenhouse gases, sea surface temperatures, ozone depleting substances, volcanic eruptions, and solar fluctuations), we are able to develop hypotheses for mechanistic drivers of FLH changes which can be rigorously tested. These efforts will contribute to the understanding of climate change over the tropical Andes Mountains, and over South America more generally, while developing techniques and hypotheses that can be applied to the study of cryosphere environments in other mountainous regions.

Fabrication of a high sensitivity and fast response self-powered photosensor based on a core-shell silicon nanowire homojunction

NASA Astrophysics Data System (ADS)

Abdul-Hameed, Assel A.; Mahdi, M. A.; Ali, Basil; Selman, Abbas M.; Al-Taay, H. F.; Jennings, P.; Lee, Wen-Jen

2018-04-01

Core-shell self-powered SiNWs homojunction photosensors have been fabricated. SiNWs are prepared by a metal assisted chemical etching method using different HF/H2O2 ratios and etching times. The length of the p-SiNWs increased as the H2O2 concentration and etching time increased. All the grown SiNWs show very low (∼0.7%) optical reflectance for the wavelength range of 200-1100 nm. Photoluminescence spectra of all prepared SiNWs show sharp and broad emission bands located in the red region of the light spectrum. Core-shell homojunction photosensors were fabricated by spin coating P2O2 onto the surface of the prepared p-SiNWs and annealed at 900 °C for 1 h. The fabricated devices exhibited photovoltaic behavior and high photosensitivity with fast response speed to the visible light. However, the sample that was fabricated using HF/H2O2 ratio of 1:1 showed the highest photosensitivity value of 3578% while the photosensor prepared using 2:1 ratio of HF/H2O2 gave the faster rise and decay time.

Thermally managed fs Z-scan methods investigation of the size-dependent nonlinearity of Graphene Oxide in different solvents

NASA Astrophysics Data System (ADS)

Burkins, Paul; Basaldua, Isaac; Kuis, Robinson; Johnson, Anthony; Swaminathan, Sivaram; Zhang, Daije; Trivedi, Sudhir; University of Maryland, Baltimore Maryland Team; Brimrose Corporation of America Collaboration

Acoustic and thermal diffusion effects are often ignored in Z-scan measurements resulting in misinterpretation of the nonlinear index of refraction and nonlinear absorption. Thermally managed Z-scan using a modified chopper was compared to utilizing a pulsepicker with the common calibration material CS2 and then extended to Graphene Oxide (GO) in different solvents. The chopper reveals properties of the material in time and is an inexpensive alternative to changing the repetition rate with a pulsepicker. The pulsepicker allows for much faster rise-times and therefore measurements can be taken before thermal effects have overwhelmed the nonlinear electronic response. GO in DI water using pulsepicked fs laser excitation yielded a value of (-1.79 +/-.6)x10-15 cm2/W for nanometer particles and (-1.09 +/-.6)x10-15 cm2/W for micrometer sized particles. Open aperture Z-scan of GO in THF using the modified chopper shows a flip from reverse saturable absorption to saturable absorption in time, previously shown to be intensity dependent, potentially resulting from thermal effects. Both measurements indicate smaller particles have larger negative nonlinearities originating from thermal effects or from defects in lattice structure at the edges.

Optimized efficiency in InP nanowire solar cells with accurate 1D analysis

NASA Astrophysics Data System (ADS)

Chen, Yang; Kivisaari, Pyry; Pistol, Mats-Erik; Anttu, Nicklas

2018-01-01

Semiconductor nanowire arrays are a promising candidate for next generation solar cells due to enhanced absorption and reduced material consumption. However, to optimize their performance, time consuming three-dimensional (3D) opto-electronics modeling is usually performed. Here, we develop an accurate one-dimensional (1D) modeling method for the analysis. The 1D modeling is about 400 times faster than 3D modeling and allows direct application of concepts from planar pn-junctions on the analysis of nanowire solar cells. We show that the superposition principle can break down in InP nanowires due to strong surface recombination in the depletion region, giving rise to an IV-behavior similar to that with low shunt resistance. Importantly, we find that the open-circuit voltage of nanowire solar cells is typically limited by contact leakage. Therefore, to increase the efficiency, we have investigated the effect of high-bandgap GaP carrier-selective contact segments at the top and bottom of the InP nanowire and we find that GaP contact segments improve the solar cell efficiency. Next, we discuss the merit of p-i-n and p-n junction concepts in nanowire solar cells. With GaP carrier selective top and bottom contact segments in the InP nanowire array, we find that a p-n junction design is superior to a p-i-n junction design. We predict a best efficiency of 25% for a surface recombination velocity of 4500 cm s-1, corresponding to a non-radiative lifetime of 1 ns in p-n junction cells. The developed 1D model can be used for general modeling of axial p-n and p-i-n junctions in semiconductor nanowires. This includes also LED applications and we expect faster progress in device modeling using our method.

Optimized efficiency in InP nanowire solar cells with accurate 1D analysis.

PubMed

Chen, Yang; Kivisaari, Pyry; Pistol, Mats-Erik; Anttu, Nicklas

2018-01-26

Semiconductor nanowire arrays are a promising candidate for next generation solar cells due to enhanced absorption and reduced material consumption. However, to optimize their performance, time consuming three-dimensional (3D) opto-electronics modeling is usually performed. Here, we develop an accurate one-dimensional (1D) modeling method for the analysis. The 1D modeling is about 400 times faster than 3D modeling and allows direct application of concepts from planar pn-junctions on the analysis of nanowire solar cells. We show that the superposition principle can break down in InP nanowires due to strong surface recombination in the depletion region, giving rise to an IV-behavior similar to that with low shunt resistance. Importantly, we find that the open-circuit voltage of nanowire solar cells is typically limited by contact leakage. Therefore, to increase the efficiency, we have investigated the effect of high-bandgap GaP carrier-selective contact segments at the top and bottom of the InP nanowire and we find that GaP contact segments improve the solar cell efficiency. Next, we discuss the merit of p-i-n and p-n junction concepts in nanowire solar cells. With GaP carrier selective top and bottom contact segments in the InP nanowire array, we find that a p-n junction design is superior to a p-i-n junction design. We predict a best efficiency of 25% for a surface recombination velocity of 4500 cm s -1 , corresponding to a non-radiative lifetime of 1 ns in p-n junction cells. The developed 1D model can be used for general modeling of axial p-n and p-i-n junctions in semiconductor nanowires. This includes also LED applications and we expect faster progress in device modeling using our method.

Different demographic, genetic, and longitudinal traits in language versus memory Alzheimer's subgroups.

PubMed

Mez, Jesse; Cosentino, Stephanie; Brickman, Adam M; Huey, Edward D; Mayeux, Richard

2013-01-01

The study's objective was to compare demographics, APOE genotypes, and rate of rise over time in functional impairment in neuropsychologically defined language, typical, and memory subgroups of clinical Alzheimer's disease (AD). 1,368 participants from the National Alzheimer's Coordinating Center database with a diagnosis of probable AD (CDR 0.5-1.0) were included. A language subgroup (n = 229) was defined as having language performance >1 SD worse than memory performance. A memory subgroup (n = 213) was defined as having memory performance >1 SD worse than language performance. A typical subgroup (n = 926) was defined as having a difference in language and memory performance of <1 SD. Compared with the memory subgroup, the language subgroup was 3.7 years older and more frequently self-identified as African American (OR = 3.69). Under a dominant genetic model, the language subgroup had smaller odds of carrying at least one APOEε4 allele relative to the memory subgroup. While this difference was present for all ages, it was more striking at a younger age (OR = 0.19 for youngest tertile; OR = 0.52 for oldest tertile). Compared with the memory subgroup, the language subgroup rose 35% faster on the Functional Assessment Questionnaire and 44% faster on CDR sum of boxes over time. Among a subset of participants who underwent autopsy (n = 98), the language, memory, and typical subgroups were equally likely to have an AD pathologic diagnosis, suggesting that variation in non-AD pathologies across subtypes did not lead to the observed differences. The study demonstrates that a language subgroup of AD has different demographics, genetic profile, and disease course in addition to cognitive phenotype.

Estimation of osmotic parameters accompanying zeatin-induced growth of detached cucumber cotyledons.

PubMed

Rayle, D L; Ross, C W; Robinson, N

1982-12-01

Water potential (psi), the osmotic potential (psi(pi)), and the pressure potential (psi(p)) of detached cotyledons isolated from Cucumis sativus L. cv Marketer seedlings after 0, 1.5, and 3 days growth with and without zeatin were determined. From zero time to 3 days, cotyledons incubated without exogenous zeatin exhibited a slight decrease in psi (from -0.4 to -1.0 bars), while those grown with zeatin developed even more negative values (about -4 bars). Both groups showed rising psi(pi) values (decreases in solutes per unit volume), but this rise was more dramatic in those treated with zeatin. These data indicate that the capacity of zeatin-treated cotyledons to take up water more rapidly than controls and thus expand faster must be due to wall loosening, as reflected in psi(p) values which declined during 3 days from about +11 bars to about +1.4 bars.It was also found that freshly detached cotyledons or those grown without exogenous zeatin exhibited osmoregulation in polyethylene glycol (PEG) solutions. That is, while cotyledons initially lost H(2)O into certain PEG solutions, their psi values decreased over time and they began absorbing water after 1 to 4 hours. After 3 days growth, zeatin-treated cotyledons had lost most of this capacity of osmoregulate. It seems likely that osmoregulation in cotyledons not treated with zeatin is due to wall loosening rather than changes in psi(pi). Zeatin-treated cotyledons with already loosened walls may not have this option to deal with water stress and thus simply come to equilibrium with external PEG solutions.

Menopausal Characteristics and Physical Functioning in Older Adulthood in the NHANES III

PubMed Central

Tom, Sarah E.; Cooper, Rachel; Patel, Kushang V.; Guralnik, Jack M.

2011-01-01

Objective We hypothesized that natural menopause would be related to better physical functioning compared to surgical menopause and that later age at menopause would be related to better physical functioning. Methods Our sample comprised 1765 women aged ≥ 60 years who participated in the National Health and Nutrition Examination Survey III, a cross-sectional study representative of the United States population. Women recalled age at final menstrual period and age at removal of the uterus and ovaries and reported age, race and ethnicity, height, weight, educational attainment, smoking status, number of children, and use of estrogen therapy. Respondents completed a walk trial and chair rises and reported functional limitations. Results Women with a surgical menopause had chair rise times that were an average of 4.4% slower than those of women with natural menopause (95% CI 0.56, 8.27). Women with natural menopause at age ≥ 55 years had an average walking speed 0.05 meters/second (95% CI 0.01, 0.10) faster than women with natural menopause at age < 45 years. Later ages at natural and surgical menopause were also related to lower self-reported functional limitation. Women with surgical menopause at age ≥ 55 years had odds of functional limitation 0.52 times (95% CI 0.29, 0.95) those of women with surgical menopause at age < 40 years, with similar patterns for natural menopause. Conclusions Women with surgical menopause and earlier age at menopause had worse physical function in older adulthood. These groups of women may benefit from interventions to prevent functional decline. PMID:21993081

The rise of artificial intelligence and the uncertain future for physicians.

PubMed

Krittanawong, C

2018-02-01

Physicians in everyday clinical practice are under pressure to innovate faster than ever because of the rapid, exponential growth in healthcare data. "Big data" refers to extremely large data sets that cannot be analyzed or interpreted using traditional data processing methods. In fact, big data itself is meaningless, but processing it offers the promise of unlocking novel insights and accelerating breakthroughs in medicine-which in turn has the potential to transform current clinical practice. Physicians can analyze big data, but at present it requires a large amount of time and sophisticated analytic tools such as supercomputers. However, the rise of artificial intelligence (AI) in the era of big data could assist physicians in shortening processing times and improving the quality of patient care in clinical practice. This editorial provides a glimpse at the potential uses of AI technology in clinical practice and considers the possibility of AI replacing physicians, perhaps altogether. Physicians diagnose diseases based on personal medical histories, individual biomarkers, simple scores (e.g., CURB-65, MELD), and their physical examinations of individual patients. In contrast, AI can diagnose diseases based on a complex algorithm using hundreds of biomarkers, imaging results from millions of patients, aggregated published clinical research from PubMed, and thousands of physician's notes from electronic health records (EHRs). While AI could assist physicians in many ways, it is unlikely to replace physicians in the foreseeable future. Let us look at the emerging uses of AI in medicine. Copyright © 2017 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Predicting tidal marsh survival or submergence to sea-level rise using Holocene data

NASA Astrophysics Data System (ADS)

Horton, B.; Shennan, I.; Bradley, S.; Cahill, N.; Kirwan, M. L.; Kopp, R. E.; Shaw, T.

2017-12-01

Rising sea level threatens to permanently submerge tidal marsh environments if they cannot accrete faster than the rate of relative sea-level rise (RSLR). But regional and global model simulations of the future ability of marshes to maintain their elevation with respect to the tidal frame are uncertain. The compilation of empirical data for tidal marsh vulnerability is, therefore, essential to address disparities across these simulations. A hitherto unexplored source of empirical data are Holocene records of tidal marsh evolution. In particular, the marshes of Great Britain have survived and submerged while RSLR varied between -7.7 and 15.2 mm/yr, primarily because of the interplay between global ice-volume changes and regional isostatic processes. Here, we reveal the limits to marsh vulnerability are revealed through the analysis of over 400 reconstructions of tidal marsh submergence and conversion to tidal mud flat or open water from 54 regions in Great Britain during the Holocene. Holocene records indicate a 90% probability of tidal marsh submergence at sites with RSLR exceeding 7.3 mm/yr (95% CI: 6.6-8.6 mm/yr). Although most modern tidal marshes in Great Britain have not yet reached these sea-level rise limits, our empirical data suggest widespread concern over their ability to survive rates of sea-level rise in the 21st century under high emission scenarios. Integrating over the uncertainties in both sea-level rise predictions and the response of tidal marshes to sea-level rise, all of Great Britain has a >80% probability of marsh submergence under RCP 8.5 by 2100, with areas of south and eastern England, where the rate of RSLR is increased by glacio-isostatic subsidence, achieving this probability by 2040.

Barriers on the brink? The complex intertwined roles of geologic framework, sediment availability and sea-level rise in island evolution

USGS Publications Warehouse

Moore, Laura; List, Jeffrey H.; Williams, S. Jeffress; Patsch, Kiki; Rosati, Julie D.; Wang, Ping; Roberts, Tiffany M.

2011-01-01

Sensitivity experiments in the North Carolina Outer Banks (OBX) have previously revealed that substrate sand proportion, followed by substrate slope, sea-level rise rate and sediment-loss rate are the most important factors in determining how barrier islands respond to sea-level rise. High sediment-loss rates and low substrate sand proportions cause barriers to be smaller and more deeply incised. Thus, as sea level rise rates increase, more deeply incised barriers do not need to migrate as far landward as larger, less-incised barriers to liberate sand from the shoreface. However, if the combination of sand losses and substrate sand proportions requires a barrier to migrate landward faster than the shoreface can erode to replenish losses, a barrier will change state and begin to disintegrate. Because the substrate of the OBXis sand-rich, these barriers are likely to persist in the near-term. In contrast, model simulations for the Chandeleur Islands, Louisiana suggest sediment loss rates are too high and/or substrate sand proportions are too low to be matched by liberation of shoreface sand. These simulations further suggest that a state change, from a landward-migrating barrier system to a subaqueous shoal complex, is either already underway or imminent.

Split-Step Timing of Professional and Junior Tennis Players

PubMed Central

Leskosek, Bojan; Filipcic, Tjasa

2017-01-01

Abstract The purpose of the study was to determine the timing of a split-step in three categories of tennis players in four groups of strokes. Subjects were divided into three groups: male and female junior, and male professional tennis players. During two tournaments, all matches were recorded with two fixed video cameras. For every stroke, the timing of the split-step between the opponent’s impact point when hitting the ball and the player’s split-step was measured. A two-way analysis of variance (ANOVA) was used to determine the differences between groups of strokes, players and the interaction Player x Stroke Group. A Tukey post-hoc test was employed to determine specific differences. The results revealed differences between players in detecting the opponent’s movement, stroke and ball flight, which were reflected in different split-step timings. Each tennis player has his/her own timing mechanism which they adapt to various game situations. Response times differ significantly depending on the game situation. On average, they are the lowest in the serve, and then gradually rise from the return of the serve to baseline game, reaching the highest values in specific game situations. Players react faster in the first serve than in the second one and in the return of the serve, the response times are lower after the return of the second serve PMID:28210342

SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion

DOE PAGES

Contreras, Carlos; Phillips, M. M.; Burns, Christopher R.; ...

2018-05-18

We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from -12 to +140 days with respect to the epoch of B-band maximum (more » $${t}_{{B}_{\\max }}$$). Supplementary imaging at the earliest epochs reveals an initial slow and nearly linear rise in luminosity with a duration of ~2.5 days, followed by a faster rising phase that is well reproduced by an explosion model with a moderate amount of 56 Ni mixing in the ejecta. From our analysis of the light curves, we conclude that: (i) the explosion occurred < 22 hr before the first detection of the supernova, (ii) the rise time to peak bolometric (λ >1800) luminosity was 16.5 ± 0.6 days, (iii) the supernova suffered little or no host-galaxy dust reddening, (iv) the peak luminosity in both the optical and near-infrared was consistent with the bright end of normal Type Ia diversity, and (v) 0.60 ± 0.15 M ⊙ of 56Ni was synthesized in the explosion. Despite its normal luminosity, SN 2012fr displayed unusually prevalent high-velocity Ca ii and Si ii absorption features, and a nearly constant photospheric velocity of the Si ii λ6355 line at ~12,000 km s -1 that began ~5 days before $${t}_{{B}_{\\max }}$$. We also highlight some of the other peculiarities in the early phase photometry and the spectral evolution. SN 2012fr also adds to a growing number of Type Ia supernovae that are hosted by galaxies with direct Cepheid distance measurements.« less

SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion

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

Contreras, Carlos; Phillips, M. M.; Burns, Christopher R.

We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from -12 to +140 days with respect to the epoch of B-band maximum (more » $${t}_{{B}_{\\max }}$$). Supplementary imaging at the earliest epochs reveals an initial slow and nearly linear rise in luminosity with a duration of ~2.5 days, followed by a faster rising phase that is well reproduced by an explosion model with a moderate amount of 56 Ni mixing in the ejecta. From our analysis of the light curves, we conclude that: (i) the explosion occurred < 22 hr before the first detection of the supernova, (ii) the rise time to peak bolometric (λ >1800) luminosity was 16.5 ± 0.6 days, (iii) the supernova suffered little or no host-galaxy dust reddening, (iv) the peak luminosity in both the optical and near-infrared was consistent with the bright end of normal Type Ia diversity, and (v) 0.60 ± 0.15 M ⊙ of 56Ni was synthesized in the explosion. Despite its normal luminosity, SN 2012fr displayed unusually prevalent high-velocity Ca ii and Si ii absorption features, and a nearly constant photospheric velocity of the Si ii λ6355 line at ~12,000 km s -1 that began ~5 days before $${t}_{{B}_{\\max }}$$. We also highlight some of the other peculiarities in the early phase photometry and the spectral evolution. SN 2012fr also adds to a growing number of Type Ia supernovae that are hosted by galaxies with direct Cepheid distance measurements.« less

A comparison between initial continuous currents of different types of upward lightning

NASA Astrophysics Data System (ADS)

Wang, D.; Sawada, N.; Takagi, N.

2009-12-01

We have observed the lightning to a wind turbine and its lightning-protection tower for four consecutive winter seasons from 2005 to 2009. Our observation items include (1) thunderstorm electrical fields and lightning-caused electric field changes at multi sites around the wind turbine, (2) electrical currents at the bottom of the wind turbine and its lightning protection tower, (3) normal video and high speed image of lightning optical channels. Totally, we have obtained the data for 42 lightning that hit either on wind turbine or its lightning protection tower or both. Among these 42 lightning, 38 are upward lightning and 2 are downward lightning. We found the upward lightning can be sub-classified into two types. Type 1 upward lightning are self-triggered from a high structure, while type 2 lightning are triggered by a discharge occurred in other places which could be either a cloud discharge or a cloud-to-ground discharge (other-triggered). In this study, we have compared the two types of upward lightning in terms of initial continuous current rise time, peak current and charge transferred to the ground. We found that the initial current of self-triggered lightning tends to rise significantly faster and to a bigger peak value than the other-triggered lightning, although both types of lightning transferred similar amount of charge to the ground.

Comparison of surface temperature in 13-lined ground squirrel (Spermophilus tridecimlineatus) and yellow-bellied marmot (Marmota flaviventris) during arousal from hibernation.

PubMed

Phillips, P K; Heath, J E

2004-08-01

Surface temperatures (Ts) of eight 13-lined ground squirrels and seven yellow-bellied marmots were measured during arousal from hibernation using infrared thermography (IRT) and recorded on videotape. Animals aroused normally in 5 degrees C cold rooms. Body temperatures were recorded during arousal using both cheek pouch and interscapular temperature probes. Warming rate in arousal was exponential. Mean mass specific warming rates show the squirrels warm faster (69.76 degrees C/h/kg) than the marmots (4.49 degrees C/h/kg). Surface temperatures (Ts) for 11 regions were measured every few minutes during arousal. The smaller ground squirrel shows the ability to perfuse distal regions without compromising rise in deep body temperature (Tb). All squirrel Ts's remained low as Tb rose to 18 degrees C, at which point, eyes opened, squirrels became more active and all Ts's rose parallel to Tb. Marmot Ts remained low as Tb rose initially. Each marmot showed a plateau phase where Tb remained constant (mean Tb 20.3+/-1.0 degrees C, duration 9.4+/-4.1 min) during which time all Ts's rose, and then remained relatively constant as Tb again began to rise. An anterior to posterior Ts gradient was evident in the ground squirrel, both body and feet. This gradient was only evident in the feet of the marmots.

How gender and task difficulty affect a sport-protective response in young adults

PubMed Central

Lipps, David B.; Eckner, James T.; Richardson, James K.; Ashton-Miller, James A.

2013-01-01

We tested the hypotheses that gender and task difficulty affect the reaction, movement, and total response times associated with performing a head protective response. Twenty-four healthy young adults (13 females) performed a protective response of raising their hands from waist level to block a foam ball fired at their head from an air cannon. Participants initially stood 8.25 m away from the cannon (‘low difficulty’), and were moved successively closer in 60 cm increments until they failed to block at least 5 of 8 balls (‘high difficulty’). Limb motion was quantified using optoelectronic markers on the participants’ left wrist. Males had significantly faster total response times (p = 0.042), a trend towards faster movement times (p = 0.054), and faster peak wrist velocity (p < .001) and acceleration (p = 0.032) than females. Reaction time, movement time, and total response time were significantly faster under high difficulty conditions for both genders (p < .001). This study suggests that baseball and softball pitchers and fielders should have sufficient time to protect their head from a batted ball under optimal conditions if they are adequately prepared for the task. PMID:23234296

Measuring science: An exploration

PubMed Central

Adams, James; Griliches, Zvi

1996-01-01

This paper examines the available United States data on academic research and development (R&D) expenditures and the number of papers published and the number of citations to these papers as possible measures of “output” of this enterprise. We look at these numbers for science and engineering as a whole, for five selected major fields, and at the individual university field level. The published data in Science and Engineering Indicators imply sharply diminishing returns to academic R&D using published papers as an “output” measure. These data are quite problematic. Using a newer set of data on papers and citations, based on an “expanding” set of journals and the newly released Bureau of Economic Analysis R&D deflators, changes the picture drastically, eliminating the appearance of diminishing returns but raising the question of why the input prices of academic R&D are rising so much faster than either the gross domestic product deflator or the implicit R&D deflator in industry. A production function analysis of such data at the individual field level follows. It indicates significant diminishing returns to “own” R&D, with the R&D coefficients hovering around 0.5 for estimates with paper numbers as the dependent variable and around 0.6 if total citations are used as the dependent variable. When we substitute scientists and engineers in place of R&D as the right-hand side variables, the coefficient on papers rises from 0.5 to 0.8, and the coefficient on citations rises from 0.6 to 0.9, indicating systematic measurement problems with R&D as the sole input into the production of scientific output. But allowing for individual university field effects drives these numbers down significantly below unity. Because in the aggregate both paper numbers and citations are growing as fast or faster than R&D, this finding can be interpreted as leaving a major, yet unmeasured, role for the contribution of spillovers from other fields, other universities, and other countries. PMID:8917477

Urban consumption of meat and milk and its green and blue water footprints-Patterns in the 1980s and 2000s for Nairobi, Kenya.

PubMed

Bosire, Caroline K; Lannerstad, Mats; de Leeuw, Jan; Krol, Maarten S; Ogutu, Joseph O; Ochungo, Pamela A; Hoekstra, Arjen Y

2017-02-01

Various studies show that the developing world experiences and will continue to experience a rise in consumption of animal proteins, particularly in cities, as a result of continued urbanization and income growth. Given the relatively large water footprint (WF) of animal products, this trend is likely to increase the pressure on already scarce water resources. We estimate, analyse and interpret the changes in consumption of meat and milk between the 1980s and 2000s for three income classes in Nairobi, the ratio of domestic production to imports, and the WF (the volume of freshwater consumed) to produce these commodities in Kenya and abroad. Nairobi's middle-income class grew much faster than the overall population. In addition, milk consumption per capita by the middle-income group grew faster than for the city's population as a whole. Contrary to expectation, average meat consumption per capita across all income groups in Nairobi declined by 11%. Nevertheless, total meat consumption increased by a factor 2.2 as a result of population growth, while total milk consumption grew by a factor 5. As a result, the total WF of meat consumption increased by a factor 2.3 and the total WF of milk consumption by a factor 4.2. The increase in milk consumption was met by increased domestic production, whereas the growth in meat consumption was partly met through imports and an enlargement of the footprint in the countries neighbouring Kenya. A likely future rise in the consumption of meat and milk in Nairobi will further enlarge the city's WF. Given Kenya's looming blue water scarcity, it is anticipated that this WF will increasingly spill over the borders of the country. Accordingly, policies aimed at meeting the rise in demand for meat and milk should consider the associated environmental constraints and the economic implications both nationally and internationally. Copyright © 2016 Elsevier B.V. All rights reserved.

Plasma concentrations of inflammatory cytokines rise rapidly during ECMO-related SIRS due to the release of preformed stores in the intestine.

PubMed

McILwain, R Britt; Timpa, Joseph G; Kurundkar, Ashish R; Holt, David W; Kelly, David R; Hartman, Yolanda E; Neel, Mary Lauren; Karnatak, Rajendra K; Schelonka, Robert L; Anantharamaiah, G M; Killingsworth, Cheryl R; Maheshwari, Akhil

2010-01-01

Extracorporeal membrane oxygenation (ECMO) is a life-saving support system used in neonates and young children with severe cardiorespiratory failure. Although ECMO has reduced mortality in these critically ill patients, almost all patients treated with ECMO develop a systemic inflammatory response syndrome (SIRS) characterized by a 'cytokine storm', leukocyte activation, and multisystem organ dysfunction. We used a neonatal porcine model of ECMO to investigate whether rising plasma concentrations of inflammatory cytokines during ECMO reflect de novo synthesis of these mediators in inflamed tissues, and therefore, can be used to assess the severity of ECMO-related SIRS. Previously healthy piglets (3-week-old) were subjected to venoarterial ECMO for up to 8 h. SIRS was assessed by histopathological analysis, measurement of neutrophil activation (flow cytometry), plasma cytokine concentrations (enzyme immunoassays), and tissue expression of inflammatory genes (PCR/western blots). Mast cell degranulation was investigated by measurement of plasma tryptase activity. Porcine neonatal ECMO was associated with systemic inflammatory changes similar to those seen in human neonates. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) concentrations rose rapidly during the first 2 h of ECMO, faster than the tissue expression of these cytokines. ECMO was associated with increased plasma mast cell tryptase activity, indicating that increased plasma concentrations of inflammatory cytokines during ECMO may result from mast cell degranulation and associated release of preformed cytokines stored in mast cells. TNF-alpha and IL-8 concentrations rose faster in plasma than in the peripheral tissues during ECMO, indicating that rising plasma levels of these cytokines immediately after the initiation of ECMO may not reflect increasing tissue synthesis of these cytokines. Mobilization of preformed cellular stores of inflammatory cytokines such as in mucosal mast cells may have an important pathophysiological role in ECMO-related SIRS.

KChIP1 modulation of Kv4.3-mediated A-type K(+) currents and repetitive firing in hippocampal interneurons.

PubMed

Bourdeau, M L; Laplante, I; Laurent, C E; Lacaille, J-C

2011-03-10

Neuronal A-type K(+) channels regulate action potential waveform, back-propagation and firing frequency. In hippocampal CA1 interneurons located at the stratum lacunosum-moleculare/radiatum junction (LM/RAD), Kv4.3 mediates A-type K(+) currents and a Kv4 β-subunit of the Kv channel interacting protein (KChIP) family, KChIP1, appears specifically expressed in these cells. However, the functional role of this accessory subunit in A-type K(+) currents and interneuron excitability remains largely unknown. Thus, first we studied KChIP1 and Kv4.3 channel interactions in human embryonic kidney 293 (HEK293) cells and determined that KChIP1 coexpression modulated the biophysical properties of Kv4.3 A-type currents (faster recovery from inactivation, leftward shift of activation curve, faster rise time and slower decay) and this modulation was selectively prevented by KChIP1 short interfering RNA (siRNA) knockdown. Next, we evaluated the effects of KChIP1 down-regulation by siRNA on A-type K(+) currents in LM/RAD interneurons in slice cultures. Recovery from inactivation of A-type K(+) currents was slower after KChIP1 down-regulation but other properties were unchanged. In addition, down-regulation of KChIP1 levels did not affect action potential waveform and firing, but increased firing frequency during suprathreshold depolarizations, indicating that KChIP1 regulates interneuron excitability. The effects of KChIP1 down-regulation were cell-specific since CA1 pyramidal cells that do not express KChIP1 were unaffected. Overall, our findings suggest that KChIP1 interacts with Kv4.3 in LM/RAD interneurons, enabling faster recovery from inactivation of A-type currents and thus promoting stronger inhibitory control of firing during sustained activity. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

A note on some statistical properties of rise time parameters used in muon arrival time measurements

NASA Technical Reports Server (NTRS)

Vanderwalt, D. J.; Devilliers, E. J.

1985-01-01

Most investigations of the muon arrival time distribution in EAS during the past decade made use of parameters which can collectively be called rise time parameters. The rise time parameter T sub A/B is defined as the time taken for the integrated pulse from a detector to rise from A% to B% of its full amplitude. The use of these parameters are usually restricted to the determination of the radial dependence thereof. This radial dependence of the rise time parameters are usually taken as a signature of the particle interaction characteristics in the shower. As these parameters have a stochastic nature, it seems reasonable that one should also take notice of this aspect of the rise time parameters. A statistical approach to rise time parameters is presented.

Age, budget and dynamics of an active salt extrusion in Iran

NASA Astrophysics Data System (ADS)

Talbot, C. J.; Jarvis, R. J.

The Hormuz salt of Kuh-e-Namak, Iran began rising through its Phanerozoic cover in Jurassic times and had surfaced by Cretaceous times. In Miocene times, the still-active Zagros folds began to develop and the salt is still extruding to feed a massive topographic dome and two surface flows of salt which have previously been called salt glaciers but are here called namakiers. Two crude but independent estimates for the rate of salt extrusion and loss are shown to balance the salt budget if the current salt dynamics are assumed to be in steady state. First, to replace the extrusive salt likely to be lost in solution in the annual rainfall, the salt must rise at an average velocity of about 11 cm a -1. Second, the foliation pattern shows that the extruding (and partially dissolved) salt column spreads under its own weight. The maximum height of the salt dome is consistent with a viscous fluid with a viscosity of 2.6 × 10 17 poises extruding from its orifice at a rate of almost 17 cm a -1. Both estimates are consistent in indicating that salt can extrude onto the surface 42-85 times faster than the average long term rate at which salt diapirs rise to the surface. The structure, fabrics, textures and deformation mechanisms of the impure halite all change along the path of the extrusive salt from the dome down the length of both namakiers. Such changes tend to occur when the flowing salt encounters changes in its boundary conditions, and the recognition of buried namakiers is discussed in the light of such observations. Episodes of salt flow at a rate of 0.5 m per day have been measured along the margin of the N namakier after significant rain showers. Such brief episodes of rapid flow alternate with long periods when the namakier is dry and stationary. The shape of the colour bands cropping out on the N namakier indicate that the flow over the surface of impure salt with a mylonitic texture obeys a power law with n ≈ 3. Although the reported annual rainfall has the potential of dissolving both namakiers in about 2000 years, a superimposed thin marine cover may protect static parts of them for as long as 30,000 to 300,000 years.

Mobility and volatility: What is behind the rising income inequality in the United States

NASA Astrophysics Data System (ADS)

Wu, Huixuan; Li, Yao

2018-02-01

Inequality of family incomes in the United States has increased significantly in the past four decades. This is largely interpreted as a result of unequal mobility, e.g., the rich can get richer at a faster pace than the rest of the population. However, using nationally representative data and the Fokker-Planck equation, our study shows that income mobility in the United States has remained stable. Instead, we find another factor - income volatility, which measures the instability of incomes - has increased considerably and caused the surge of income inequality. In addition, the rising volatility is associated with the plummeting of income-growth opportunity, creating the feeling that the American Dream is in decline. Volatility has often been overlooked in previous studies on inequality, partially because mobility and volatility are usually studied separately. By contrast, the Fokker-Planck equation takes both mobility and volatility into consideration, making it a more comprehensive model.

Dual Control of Giant Field-like Spin Torque in Spin Filter Tunnel Junctions

PubMed Central

Tang, Y. -H.; Chu, F. -C.; Kioussis, Nicholas

2015-01-01

We predict a giant field-like spin torque, , in spin-filter (SF) barrier tunnel junctions in sharp contrast to existing junctions based on nonmagnetic passive barriers. We demonstrate that has linear bias behavior, is independent of the SF thickness, and has odd parity with respect to the SF’s exchange splitting. Thus, it can be selectively controlled via external bias or external magnetic field which gives rise to sign reversal of via magnetic field switching. The underlying mechanism is the interlayer exchange coupling between the noncollinear magnetizations of the SF and free ferromagnetic electrode via the nonmagnetic insulating (I) spacer giving rise to giant spin-dependent reflection at the SF/I interface. These findings suggest that the proposed field-like-spin-torque MRAM may provide promising dual functionalities for both ‘reading’ and ‘writing’ processes which require lower critical current densities and faster writing and reading speeds. PMID:26095146

One-dimensional non-LTE time-dependent radiative transfer of an He-detonation model and the connection to faint and fast-decaying supernovae

NASA Astrophysics Data System (ADS)

Dessart, Luc; Hillier, D. John

2015-02-01

We present non-LTE (non-Local-Thermodynamic-Equilibrium) time-dependent radiative transfer simulations for ejecta produced by the detonation of a helium shell at the surface of a low-mass carbon/oxygen white dwarf (WD). This mechanism is one possible origin for supernovae (SNe) with faint and fast-decaying light curves, such as .Ia SNe and Ca-rich transients. Our initial ejecta conditions at 1 d are given by the 0.18 B explosion model COp45HEp2 of Waldman et al. The 0.2 M⊙ ejecta initially contains 0.11 M⊙ of He, 0.03 M⊙ of Ca, and 0.03 M⊙ of Ti. We obtain an ˜ 5 d rise to a bolometric maximum of 3.59 × 1041 erg s-1, primarily powered by 48V decay. Multi-band light curves show distinct morphologies, with a rise to maximum magnitude (-14.3 to -16.7 mag) that varies between 3 to 9 d from the U to the K bands. Near-IR light curves show no secondary maximum. Because of the presence of both He I and Si II lines at early times we obtain a hybrid Type Ia/Ib classification. During the photospheric phase line blanketing is caused primarily by Ti II. At nebular times, the spectra show strong Ca II lines in the optical (but no [O I] 6300-6364 Å emission), and Ti II in the near-IR. Overall, these results match qualitatively the very disparate properties of .Ia SNe and Ca-rich transients. Although the strong Ti II blanketing and red colours that we predict are rarely observed, they are seen, for example, in OGLE-2013- SN-079. Furthermore, we obtain a faster light-curve evolution than, for example, PTF10iuv, indicating an ejecta mass >0.2 M⊙. An alternate scenario may be the merger of two WDs, one or both composed of He.

Froissart bound and self-similarity based models of proton structure functions

NASA Astrophysics Data System (ADS)

Choudhury, D. K.; Saikia, Baishali

2018-03-01

Froissart bound implies that the total proton-proton cross-section (or equivalently proton structure function) cannot rise faster than log2s ˜log2 1 x. Compatibility of such behavior with the notion of self-similarity in proton structure function was suggested by us sometime back. In the present work, we generalize and improve it further by considering more recent self-similarity based models of proton structure functions and compare with recent data as well as with the model of Block, Durand, Ha and McKay.

Characterization of spontaneous excitatory synaptic currents in salamander retinal ganglion cells.

PubMed Central

Taylor, W R; Chen, E; Copenhagen, D R

1995-01-01

1. Spontaneous excitatory postsynaptic currents (sEPSCs) were recorded under voltage-clamp conditions. Consistent with activation of non-NMDA-type glutamate receptors, the sEPSCs reversed at potentials above 0 mV, were blocked by 1 microM CNQX and prolonged by 2 mM aniracetam. 2. The peak conductance of the averaged sEPSCs (n = 70-400) was 130 +/- 60 pS (mean +/- S.D.; 17 cells, ranging from 70 to 290 pS). Amplitude distributions were skewed towards larger amplitudes. 3. The decay of individual and mean sEPSCs was exponential with a mean time constant (tau d) of 3.75 +/- 0.84 ms (n = 13), which was voltage independent. The 10-90% rise time of the sEPSCs was 1.30 +/- 0.44 ms (n = 13). There was no correlation between sEPSC rise time and tau d suggesting that dendritic filtering alone did not shape the time course of sEPSCs. 4. Light-evoked EPSCs in these retinal ganglion cells are mediated by concomitant activation of NMDA and non-NMDA receptors; however, no NMDA component was discerned in the sEPSCs, even when recording at -96 mV in Mg(2+)-free solutions. The decay time course was not altered by 20 microM AP7, an NMDA antagonist, nor was an NMDA component unmasked by adding glycine or D-serine. These results suggest that NMDA and non-NMDA receptors are not coactivated by a single vesicle of transmitter during spontaneous release, and thus are probably not colocalized in the postsynaptic membrane at the sites of spontaneous release. 5. The sEPSCs were an order of magnitude faster than the non-NMDA receptor-mediated EPSCs evoked by light stimuli, and it is proposed that the EPSC time course is determined largely by the extended time course of release of synaptic vesicles from bipolar cells. The quantal content of a light-evoked non-NMDA receptor-mediated EPSC in an on-off cell is about 200 quanta. Images Figure 6 PMID:7562636

Compensated pulsed alternator

DOEpatents

Weldon, William F.; Driga, Mircea D.; Woodson, Herbert H.

1980-01-01

This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak outout. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit.

Implications of net energy-return-on-investment for a low-carbon energy transition

NASA Astrophysics Data System (ADS)

King, Lewis C.; van den Bergh, Jeroen C. J. M.

2018-04-01

Low-carbon energy transitions aim to stay within a carbon budget that limits potential climate change to 2 °C—or well below—through a substantial growth in renewable energy sources alongside improved energy efficiency and carbon capture and storage. Current scenarios tend to overlook their low net energy returns compared to the existing fossil fuel infrastructure. Correcting from gross to net energy, we show that a low-carbon transition would probably lead to a 24-31% decline in net energy per capita by 2050, which implies a strong reversal of the recent rising trends of 0.5% per annum. Unless vast end-use efficiency savings can be achieved in the coming decades, current lifestyles might be impaired. To maintain the present net energy returns, solar and wind renewable power sources should grow two to three times faster than in other proposals. We suggest a new indicator, `energy return on carbon', to assist in maximizing the net energy from the remaining carbon budget.

Indirect contact freeze water desalination for an ice maker machine - CFD simulation

NASA Astrophysics Data System (ADS)

Jayakody, Harith; Al-Dadah, Raya; Mahmoud, Saad

2017-11-01

To offer for potable water shortages, sea water desalination is a potential solution for the global rising demand for fresh water. The latent heat of fusion is about one-seventh the latent heat of vaporisation, thus indicating the benefit of lower energy consumption for the freeze desalination process. Limited literature is reported on computational fluid dynamics (CFD) on freeze desalination. Therefore, analysing and investigating thermodynamic processes are easily conducted by the powerful tool of CFD. A single unit of ice formation in an ice maker machine was modelled using ANSYS Fluent software three-dimensionally. Energy, species transport and solidification/melting modules were used in building the CFD model. Parametric analysis was conducted using the established CFD model to predict the effects of freezing temperature and the geometry of the ice maker machine; on ice production and the freezing time. Lower freezing temperatures allowed more ice production and faster freezing. Increasing the diameter and the length of the freezing tube enabled more ice to be produced.

Can Arctic sea-ice melt be explained by atmospheric meridional transports? (Invited)

NASA Astrophysics Data System (ADS)

Tjernstrom, M. K.; Graversen, R. G.

2010-12-01

The Arctic summer sea ice is melting away at an alarming rate, and it is now expected that an principally sea-ice free Arctic summer will occur much earlier than projected by the IPCC AR4 models. At the same time Arctic near-surface temperatures are rising at a rate much faster than the global average. The processes responsible for these changes are debated and many claim that local feedbacks, such as the surface albedo feedback, are the main culprits while other argue that remote effects, such as atmospheric circulation changes on synoptic and hemispheric scales, are the most important. We will explore the effects of the meridional transport by synoptic and larger scale atmospheric circulation on recent changes, using reanalysis data. It will be illustarated how this transport can contribute significant amounts of sensible heat, but also of atmospheric moisture such that local cloud feedbacks as well as the direct greenhouse effect of the water vapor contributes significantly to the surface energy balance over the Arctic polar cap.

Emergent ultrafast phenomena in correlated oxides and heterostructures

NASA Astrophysics Data System (ADS)

Gandolfi, M.; Celardo, G. L.; Borgonovi, F.; Ferrini, G.; Avella, A.; Banfi, F.; Giannetti, C.

2017-03-01

The possibility of investigating the dynamics of solids on timescales faster than the thermalization of the internal degrees of freedom has disclosed novel non-equilibrium phenomena that have no counterpart at equilibrium. Transition metal oxides (TMOs) provide an interesting playground in which the correlations among the charges in the metal d-orbitals give rise to a wealth of intriguing electronic and thermodynamic properties involving the spin, charge, lattice and orbital orders. Furthermore, the physical properties of TMOs can be engineered at the atomic level, thus providing the platform to investigate the transport phenomena on timescales of the order of the intrinsic decoherence time of the charge excitations. Here, we review and discuss three paradigmatic examples of transient emerging properties that are expected to open new fields of research: (i) the creation of non-thermal magnetic states in spin-orbit Mott insulators; (ii) the possible exploitation of quantum paths for the transport and collection of charge excitations in heterostructures; (iii) the transient wave-like behavior of the temperature field in strongly anisotropic TMOs.

Sea level rise at Honolulu and Hilo, Hawaii: GPS estimates of differential land motion

NASA Astrophysics Data System (ADS)

Caccamise, Dana J.; Merrifield, Mark A.; Bevis, Michael; Foster, James; Firing, Yvonne L.; Schenewerk, Mark S.; Taylor, Frederick W.; Thomas, Donald A.

2005-02-01

Since 1946, sea level at Hilo on the Big Island of Hawaii has risen an average of 1.8 +/- 0.4 mm/yr faster than at Honolulu on the island of Oahu. This difference has been attributed to subsidence of the Big Island. However, GPS measurements indicate that Hilo is sinking relative to Honolulu at a rate of -0.4 +/- 0.5 mm/yr, which is too small to account for the difference in sea level trends. In the past 30 years, there has been a statistically significant reduction in the relative sea level trend. While it is possible that the rates of land motion have changed over this time period, the available hydrographic data suggest that interdecadal variations in upper ocean temperature account for much of the differential sea level signal between the two stations, including the recent trend change. These results highlight the challenges involved in estimating secular sea level trends in the presence of significant low frequency variability.

Forest stand growth dynamics in Central Europe have accelerated since 1870

PubMed Central

Pretzsch, Hans; Biber, Peter; Schütze, Gerhard; Uhl, Enno; Rötzer, Thomas

2014-01-01

Forest ecosystems have been exposed to climate change for more than 100 years, whereas the consequences on forest growth remain elusive. Based on the oldest existing experimental forest plots in Central Europe, we show that, currently, the dominant tree species Norway spruce and European beech exhibit significantly faster tree growth (+32 to 77%), stand volume growth (+10 to 30%) and standing stock accumulation (+6 to 7%) than in 1960. Stands still follow similar general allometric rules, but proceed more rapidly through usual trajectories. As forest stands develop faster, tree numbers are currently 17–20% lower than in past same-aged stands. Self-thinning lines remain constant, while growth rates increase indicating the stock of resources have not changed, while growth velocity and turnover have altered. Statistical analyses of the experimental plots, and application of an ecophysiological model, suggest that mainly the rise in temperature and extended growing seasons contribute to increased growth acceleration, particularly on fertile sites. PMID:25216297

Dyslexics’ faster decay of implicit memory for sounds and words is manifested in their shorter neural adaptation

PubMed Central

Jaffe-Dax, Sagi; Frenkel, Or; Ahissar, Merav

2017-01-01

Dyslexia is a prevalent reading disability whose underlying mechanisms are still disputed. We studied the neural mechanisms underlying dyslexia using a simple frequency-discrimination task. Though participants were asked to compare the two tones in each trial, implicit memory of previous trials affected their responses. We hypothesized that implicit memory decays faster among dyslexics. We tested this by increasing the temporal intervals between consecutive trials, and by measuring the behavioral impact and ERP responses from the auditory cortex. Dyslexics showed a faster decay of implicit memory effects on both measures, with similar time constants. Finally, faster decay of implicit memory also characterized the impact of sound regularities in benefitting dyslexics' oral reading rate. Their benefit decreased faster as a function of the time interval from the previous reading of the same non-word. We propose that dyslexics’ shorter neural adaptation paradoxically accounts for their longer reading times, since it reduces their temporal window of integration of past stimuli, resulting in noisier and less reliable predictions for both simple and complex stimuli. Less reliable predictions limit their acquisition of reading expertise. DOI: http://dx.doi.org/10.7554/eLife.20557.001 PMID:28115055

More Symmetrical Children Have Faster and More Consistent Choice Reaction Times

ERIC Educational Resources Information Center

Hope, David; Bates, Timothy C.; Dykiert, Dominika; Der, Geoff; Deary, Ian J.

2015-01-01

Greater cognitive ability in childhood is associated with increased longevity, and speedier reaction time (RT) might account for much of this linkage. Greater bodily symmetry is linked to both higher cognitive test scores and faster RTs. It is possible, then, that differences in bodily system integrity indexed by symmetry may underlie the…

Music Enhances Sleep in Preschool Children.

ERIC Educational Resources Information Center

Field, Tiffany

1999-01-01

Examined the effect of playing background classical guitar music at nap time on alternate days to toddlers and preschool children attending a model preschool. Specifically assessed music's effect on nap-time sleep onset. Found that children fell asleep faster on the music days than on the nonmusic days. Toddlers fell asleep faster than did the…

Irreversible ocean thermal expansion under carbon dioxide removal

NASA Astrophysics Data System (ADS)

Ehlert, Dana; Zickfeld, Kirsten

2018-03-01

In the Paris Agreement in 2015 countries agreed on holding global mean surface air warming to well below 2 °C above pre-industrial levels, but the emission reduction pledges under that agreement are not ambitious enough to meet this target. Therefore, the question arises of whether restoring global warming to this target after exceeding it by artificially removing CO2 from the atmosphere is possible. One important aspect is the reversibility of ocean heat uptake and associated sea level rise, which have very long (centennial to millennial) response timescales. In this study the response of sea level rise due to thermal expansion to a 1 % yearly increase of atmospheric CO2 up to a quadrupling of the pre-industrial concentration followed by a 1 % yearly decline back to the pre-industrial CO2 concentration is examined using the University of Victoria Earth System Climate Model (UVic ESCM). We find that global mean thermosteric sea level (GMTSL) continues to rise for several decades after atmospheric CO2 starts to decline and does not return to pre-industrial levels for over 1000 years after atmospheric CO2 is restored to the pre-industrial concentration. This finding is independent of the strength of vertical sub-grid-scale ocean mixing implemented in the model. Furthermore, GMTSL rises faster than it declines in response to a symmetric rise and decline in atmospheric CO2 concentration partly because the deep ocean continues to warm for centuries after atmospheric CO2 returns to the pre-industrial concentration. Both GMTSL rise and decline rates increase with increasing vertical ocean mixing. Exceptions from this behaviour arise if the overturning circulations in the North Atlantic and Southern Ocean intensify beyond pre-industrial levels in model versions with lower vertical mixing, which leads to rapid cooling of the deep ocean.

Breaking the Myth That Relay Swimming Is Faster Than Individual Swimming.

PubMed

Skorski, Sabrina; Etxebarria, Naroa; Thompson, Kevin G

2016-04-01

To investigate if swimming performance is better in a relay race than in the corresponding individual race. The authors analyzed 166 elite male swimmers from 15 nations in the same competition (downloaded from www.swimrankings.net). Of 778 observed races, 144 were Olympic Games performances (2000, 2004, 2012), with the remaining 634 performed in national or international competitions. The races were 100-m (n = 436) and 200-m (n = 342) freestyle events. Relay performance times for the 2nd-4th swimmers were adjusted (+ 0.73 s) to allow for the "flying start." Without any adjustment, mean individual relay performances were significantly faster for the first 50 m and overall time in the 100-m events. Furthermore, the first 100 m of the 200-m relay was significantly faster (P > .001). During relays, swimmers competing in 1st position did not show any difference compared with their corresponding individual performance (P > .16). However, swimmers competing in 2nd-4th relay-team positions demonstrated significantly faster times in the 100-m (P < .001) and first half of the 200-m relays than in their individual events (P < .001, ES: 0.28-1.77). However, when finishing times for 2nd-4th relay team positions were adjusted for the flying start no differences were detected between relay and individual race performance for any event or split time (P > .17). Highly trained swimmers do not swim (or turn) faster in relay events than in their individual races. Relay exchange times account for the difference observed in individual vs relay performance.

Blockade of nitric oxide formation enhances thermal and behavioral responses in rats during turpentine abscess.

PubMed

Soszynski, D

2000-01-01

The purpose of this study was to investigate the role of nitric oxide (NO) during the development of fever and other symptoms of sickness behavior (i.e. anorexia, cachexia) in response to localized tissue inflammation caused by injection of turpentine in freely moving biotelemetered rats. To determine the role of NO in turpentine-induced fever, we injected the NO synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) intraperitoneally simultaneously or 5 h after turpentine injection. Rats responded with fever to intramuscular injection of 20 microl of turpentine that commenced 6 h after injection and reached peak values 11 h after injection. Although turpentine did not significantly alter food and water intake, it caused a drop in body weight. Rats injected with turpentine and treated with L-NAME responded with a substantial rise in fever, independently of the time of L-NAME injection. The rise in body temperature (T(b)) due to turpentine injection began slightly sooner and reached the maximal T(b) value faster in rats treated with L-NAME than in the ones treated with saline (control for L-NAME). The enhanced decrease in food and water intake in rats treated with a combination of L-NAME and turpentine was also observed. As a result, L-NAME-injected rats responded with a profound drop in body mass due to turpentine, independently of the time of L-NAME injection. L-NAME alone did not affect food and water intake, but slightly suppressed the gain of body mass. These results indirectly indicate that NO is involved in pyrogenic and behavioral responses in rats during turpentine abscess. Copyright 2001 S. Karger AG, Basel.

DES14X3taz: A TYPE I SUPERLUMINOUS SUPERNOVA SHOWING A LUMINOUS, RAPIDLY COOLING INITIAL PRE-PEAK BUMP

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

Smith, M.; Sullivan, M.; D’Andrea, C. B.

2016-02-03

We present DES14X3taz, a new hydrogen-poor superluminous supernova (SLSN-I) discovered by the Dark Energy Survey (DES) supernova program, with additional photometric data provided by the Survey Using DECam for Superluminous Supernovae. Spectra obtained using Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy on the Gran Telescopio CANARIAS show DES14X3taz is an SLSN-I at z = 0.608. Multi-color photometry reveals a double-peaked light curve: a blue and relatively bright initial peak that fades rapidly prior to the slower rise of the main light curve. Our multi-color photometry allows us, for the first time, to show that the initial peak cools frommore » 22,000 to 8000 K over 15 rest-frame days, and is faster and brighter than any published core-collapse supernova, reaching 30% of the bolometric luminosity of the main peak. No physical Ni-56-powered model can fit this initial peak. We show that a shock-cooling model followed by a magnetar driving the second phase of the light curve can adequately explain the entire light curve of DES14X3taz. Models involving the shock-cooling of extended circumstellar material at a distance of similar or equal to 400 R-circle dot are preferred over the cooling of shock-heated surface layers of a stellar envelope. We compare DES14X3taz to the few double-peaked SLSN-I events in the literature. Although the rise. times and characteristics of these initial peaks differ, there exists the tantalizing possibility that they can be explained by one physical interpretation« less

DES14X3taz: A type I superluminous supernova showing a luminous, rapidly cooling initial pre-peak bump

DOE PAGES

Smith, M.

2016-02-03

Here, we present DES14X3taz, a new hydrogen-poor superluminous supernova (SLSN-I) discovered by the Dark Energy Survey (DES) supernova program, with additional photometric data provided by the Survey Using DECam for Superluminous Supernovae. Spectra obtained using Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy on the Gran Telescopio CANARIAS show DES14X3taz is an SLSN-I at z = 0.608. Multi-color photometry reveals a double-peaked light curve: a blue and relatively bright initial peak that fades rapidly prior to the slower rise of the main light curve. Our multi-color photometry allows us, for the first time, to show that the initial peak cools from 22,000more » to 8000 K over 15 rest-frame days, and is faster and brighter than any published core-collapse supernova, reaching 30% of the bolometric luminosity of the main peak. No physical (56)Ni-powered model can fit this initial peak. We show that a shock-cooling model followed by a magnetar driving the second phase of the light curve can adequately explain the entire light curve of DES14X3taz. Models involving the shock-cooling of extended circumstellar material at a distance of ≃400 R ⊙ are preferred over the cooling of shock-heated surface layers of a stellar envelope. We compare DES14X3taz to the few double-peaked SLSN-I events in the literature. Although the rise times and characteristics of these initial peaks differ, there exists the tantalizing possibility that they can be explained by one physical interpretation.« less

Estimation of Osmotic Parameters Accompanying Zeatin-Induced Growth of Detached Cucumber Cotyledons 1

PubMed Central

Rayle, David L.; Ross, Cleon W.; Robinson, Nina

1982-01-01

Water potential (ψ), the osmotic potential (ψπ), and the pressure potential (ψp) of detached cotyledons isolated from Cucumis sativus L. cv Marketer seedlings after 0, 1.5, and 3 days growth with and without zeatin were determined. From zero time to 3 days, cotyledons incubated without exogenous zeatin exhibited a slight decrease in ψ (from −0.4 to −1.0 bars), while those grown with zeatin developed even more negative values (about −4 bars). Both groups showed rising ψπ values (decreases in solutes per unit volume), but this rise was more dramatic in those treated with zeatin. These data indicate that the capacity of zeatin-treated cotyledons to take up water more rapidly than controls and thus expand faster must be due to wall loosening, as reflected in ψp values which declined during 3 days from about +11 bars to about +1.4 bars. It was also found that freshly detached cotyledons or those grown without exogenous zeatin exhibited osmoregulation in polyethylene glycol (PEG) solutions. That is, while cotyledons initially lost H2O into certain PEG solutions, their ψ values decreased over time and they began absorbing water after 1 to 4 hours. After 3 days growth, zeatin-treated cotyledons had lost most of this capacity of osmoregulate. It seems likely that osmoregulation in cotyledons not treated with zeatin is due to wall loosening rather than changes in ψπ. Zeatin-treated cotyledons with already loosened walls may not have this option to deal with water stress and thus simply come to equilibrium with external PEG solutions. PMID:16662734

Enhancement of Attentional Performance by Selective Stimulation of α4β2* nAChRs: Underlying Cholinergic Mechanisms

PubMed Central

Howe, William M; Ji, Jinzhao; Parikh, Vinay; Williams, Sarah; Mocaër, Elisabeth; Trocmé-Thibierge, Caryn; Sarter, Martin

2010-01-01

Impairments in attention are a major component of the cognitive symptoms of neuropsychiatric and neurodegenerative disorders. Using an operant sustained attention task (SAT), including a distractor condition (dSAT), we assessed the putative pro-attentional effects of the selective α4β2* nicotinic acetylcholine receptor (nAChR) agonist S 38232 in comparison with the non-selective agonist nicotine. Neither drug benefited SAT performance. However, in interaction with the increased task demands implemented by distractor presentation, the selective agonist, but not nicotine, enhanced the detection of signals during the post-distractor recovery period. This effect is consistent with the hypothesis that second-long increases in cholinergic activity (‘transients') mediate the detection of cues and that nAChR agonists augment such transients. Electrochemical recordings of prefrontal cholinergic transients evoked by S 38232 and nicotine indicated that the α4β2* nAChR agonist evoked cholinergic transients that were characterized by a faster rise time and more rapid decay than those evoked by nicotine. Blockade of the α7 nAChR ‘sharpens' nicotine-evoked transients; therefore, we determined the effects of co-administration of nicotine and the α7 nAChR antagonist methyllycaconitine on dSAT performance. Compared with vehicle and nicotine alone, this combined treatment significantly enhanced the detection of signals. These results indicate that compared with nicotine, α4β2* nAChR agonists significantly enhance attentional performance and that the dSAT represents a useful behavioral screening tool. The combined behavioral and electrochemical evidence supports the hypothesis that nAChR agonist-evoked cholinergic transients, which are characterized by rapid rise time and fast decay, predict robust drug-induced enhancement of attentional performance. PMID:20147893

Relaxation and turbulence effects on sonic boom signatures

NASA Technical Reports Server (NTRS)

Pierce, Allan D.; Sparrow, Victor W.

1992-01-01

The rudimentary theory of sonic booms predicts that the pressure signatures received at the ground begin with an abrupt shock, such that the overpressure is nearly abrupt. This discontinuity actually has some structure, and a finite time is required for the waveform to reach its peak value. This portion of the waveform is here termed the rise phase, and it is with this portion that this presentation is primarily concerned. Any time characterizing the duration of the rise phase is loosely called the 'rise time.' Various definitions are used in the literature for this rise time. In the present discussion the rise time can be taken as the time for the waveform to rise from 10 percent of its peak value to 90 percent of its peak value. The available data on sonic booms that appears in the open literature suggests that typical values of shock over-pressure lie in the range of 30 Pa to 200 Pa, typical values of shock duration lie in the range of 150 ms to 250 ms, and typical values of the rise time lie in the range of 1 ms to 5 ms. The understanding of the rise phase of sonic booms is important because the perceived loudness of a shock depends primarily on the structure of the rise phase. A longer rise time typically implies a less loud shock. A primary question is just what physical mechanisms are most important for the determination of the detailed structure of the rise phase.

Sex-specific impact of prenatal stress on growth and reproductive parameters of guinea pigs.

PubMed

Schöpper, Hanna; Klaus, Teresa; Palme, Rupert; Ruf, Thomas; Huber, Susanne

2012-12-01

Body condition and reproductive maturation are parameters of reproductive success that are influenced by sexual hormones rising in the circulation during the time of puberty. Various endocrine systems can be programmed by conditions experienced during early life. Stress for instance is supposed to be capable of influencing fetal development, leading to adjustments of offspring's later physiology. We examined whether prenatal stress (induced by exposure to strobe light) during early- to mid-gestation was capable of affecting later reproductive parameters in guinea pigs (Cavia aperea f. porcellus). Therefore, we measured the levels of testosterone and progesterone from the age of day 12-124 in prenatally stressed (PS, n = 20) and unaffected control animals (n = 24). Furthermore, we determined the timing of puberty and growth. Body weight development revealed significantly faster growth in PS females compared to control animals. The onset of first estrus was slightly earlier in PS females, however not significantly so. Cycle lengths and levels of progesterone differed between groups over the course of time with higher progesterone levels and more constant cycles among PS females compared to control females who displayed marked differences between first and subsequent cycles. Levels of testosterone did not differ between groups. We conclude that prenatal stress accelerates growth and maturity in females, but not in males.

Accelerating moderately stiff chemical kinetics in reactive-flow simulations using GPUs

NASA Astrophysics Data System (ADS)

Niemeyer, Kyle E.; Sung, Chih-Jen

2014-01-01

The chemical kinetics ODEs arising from operator-split reactive-flow simulations were solved on GPUs using explicit integration algorithms. Nonstiff chemical kinetics of a hydrogen oxidation mechanism (9 species and 38 irreversible reactions) were computed using the explicit fifth-order Runge-Kutta-Cash-Karp method, and the GPU-accelerated version performed faster than single- and six-core CPU versions by factors of 126 and 25, respectively, for 524,288 ODEs. Moderately stiff kinetics, represented with mechanisms for hydrogen/carbon-monoxide (13 species and 54 irreversible reactions) and methane (53 species and 634 irreversible reactions) oxidation, were computed using the stabilized explicit second-order Runge-Kutta-Chebyshev (RKC) algorithm. The GPU-based RKC implementation demonstrated an increase in performance of nearly 59 and 10 times, for problem sizes consisting of 262,144 ODEs and larger, than the single- and six-core CPU-based RKC algorithms using the hydrogen/carbon-monoxide mechanism. With the methane mechanism, RKC-GPU performed more than 65 and 11 times faster, for problem sizes consisting of 131,072 ODEs and larger, than the single- and six-core RKC-CPU versions, and up to 57 times faster than the six-core CPU-based implicit VODE algorithm on 65,536 ODEs. In the presence of more severe stiffness, such as ethylene oxidation (111 species and 1566 irreversible reactions), RKC-GPU performed more than 17 times faster than RKC-CPU on six cores for 32,768 ODEs and larger, and at best 4.5 times faster than VODE on six CPU cores for 65,536 ODEs. With a larger time step size, RKC-GPU performed at best 2.5 times slower than six-core VODE for 8192 ODEs and larger. Therefore, the need for developing new strategies for integrating stiff chemistry on GPUs was discussed.

Automatic EEG spike detection.

PubMed

Harner, Richard

2009-10-01

Since the 1970s advances in science and technology during each succeeding decade have renewed the expectation of efficient, reliable automatic epileptiform spike detection (AESD). But even when reinforced with better, faster tools, clinically reliable unsupervised spike detection remains beyond our reach. Expert-selected spike parameters were the first and still most widely used for AESD. Thresholds for amplitude, duration, sharpness, rise-time, fall-time, after-coming slow waves, background frequency, and more have been used. It is still unclear which of these wave parameters are essential, beyond peak-peak amplitude and duration. Wavelet parameters are very appropriate to AESD but need to be combined with other parameters to achieve desired levels of spike detection efficiency. Artificial Neural Network (ANN) and expert-system methods may have reached peak efficiency. Support Vector Machine (SVM) technology focuses on outliers rather than centroids of spike and nonspike data clusters and should improve AESD efficiency. An exemplary spike/nonspike database is suggested as a tool for assessing parameters and methods for AESD and is available in CSV or Matlab formats from the author at brainvue@gmail.com. Exploratory Data Analysis (EDA) is presented as a graphic method for finding better spike parameters and for the step-wise evaluation of the spike detection process.

Facile Fabrication of Ordered Anodized Aluminum Oxide Membranes with Controlled Pore Size by Improved Hard Anodization.

PubMed

Fan, Jiangxia; Zhu, Xinxin; Wang, Kunzhou; Chen, Xiaoyuan; Wang, Xinqing; Yan, Minhao; Ren, Yong

2018-05-01

We have fabricated highly ordered anodized aluminum oxide (AAO) membranes with different diameter through improved hard anodization (HA) at high temperature. This process can generate thick AAO membranes (30 μm) in a short anodizing time with high growth rate 20-60 μm h-1 which is much faster than that in traditional mild two-step anodization. We enlarged the AAO pore diameter by adjusting the voltage rise rate at the same time, which has a great influence on current density and temperature. The AAO pore diameter varies from 60-110 nm to 160-190 nm. The pore diameter (Dp) of the AAO prepared by this improved process is much larger than that prepared by HA (40-60 nm) when H2C2O4 as electrolyte. It can expand potential use of the AAO membranes such as for the template-based synthesis of nanowires or nanotubes with modulated diameters and also for practical separation technology. We also has used the AAO with different diameters prepared by this improved HA to fabricate Co nanowires and γ-Fe2O3 superparamagnetic nanorods.

Effects of rehabilitative horse riding on the Sit-to-Stand action of the adolescent with brain lesions.

PubMed

Lee, Jang Won; Han, A-Reum; Kim, Kihong

2014-02-01

The purpose of this study was to investigate the balance abilities of the adolescent girl with brain lesions by Sit-to-Stand (STS) action analysis before and after the rehabilitative horse riding of 16 week program. The subject aged 16 yr old who had the disabilities of spasticity and hemiplegia was recruited with the consent approval. The equilibrium abilities of the subject were tested by Sit-to-Stand examination with Weight Transfer Time (WTT), Mean Rising Index (MRI), Mean Weight Asymmetry (MWA), Max Trunk Flexion Velocity (MTFV), and Max Trunk Extension Velocity (MTEV). Research was designed by AB single subject study with baseline of 3 times of measurement and rehabilitative horse riding treatments. In the results, the enhancement of the subject's equilibrium ability was shown from the comparisons between baseline and treatment by the STS test that WTT was 2.37 sec faster, MRI was 6.64 N/kg higher, and MWA was 8.12% lower, and MTFV was 0.57°/sec larger than all those means of baseline. It suggested that the subject showed her enhanced balance ability while in sitting and standing after the rehabilitative horse riding treatments.

Faster Increases in Human Life Expectancy Could Lead to Slower Population Aging

PubMed Central

2015-01-01

Counterintuitively, faster increases in human life expectancy could lead to slower population aging. The conventional view that faster increases in human life expectancy would lead to faster population aging is based on the assumption that people become old at a fixed chronological age. A preferable alternative is to base measures of aging on people’s time left to death, because this is more closely related to the characteristics that are associated with old age. Using this alternative interpretation, we show that faster increases in life expectancy would lead to slower population aging. Among other things, this finding affects the assessment of the speed at which countries will age. PMID:25876033

Selecting the best tone-pip stimulus-envelope time for estimating an objective middle-latency response threshold for low- and middle-tone sensorineural hearing losses.

PubMed

Xu, Z M; De Vel, E; Vinck, B; Van Cauwenberge, P

1995-01-01

The effects of rise-fall and plateau times for the Pa component of the middle-latency response (MLR) were investigated in normally hearing subjects, and an objective MLR threshold was measured in patients with low- and middle-tone hearing losses, using a selected stimulus-envelope time. Our results showed that the stimulus-envelope time (the rise-fall time and plateau time groups) affected the Pa component of the MLR (quality was determined by the (chi 2-test and amplitude by the F-test). The 4-2-4 tone-pips produced good Pa quality by visual inspection. However, our data revealed no statistically significant Na-Pa amplitude differences between the two subgroups studied when comparing the 2- and 4-ms rise-fall times and the 0- and 2-ms plateau times. In contrast, Na-Pa became significantly smaller from the 4-ms to the 6-ms rise-fall time and from the 2-ms to the 4-ms plateau time (paired t-test). This result allowed us to select the 2- or 4-ms rise-fall time and the 0- or 2-ms plateau time without influencing amplitude. Analysis of the stimulus spectral characteristics demonstrated that a rise-fall time of at least 2ms could prevent spectral splatter and indicated that a stimulus with a 5-ms rise-fall time had a greater frequency-specificity than a stimulus of 2-ms rise-fall time. When considering the synchronous discharge and frequency-specificity of MLR, our findings show that a rise-fall time of four periods with a plateau of two periods is an acceptable compromise for estimating the objective MLR threshold.(ABSTRACT TRUNCATED AT 250 WORDS)

Early evolution of an energetic coronal mass ejection and its relation to EUV waves

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

Liu, Rui; Wang, Yuming; Shen, Chenglong, E-mail: rliu@ustc.edu.cn

2014-12-10

We study a coronal mass ejection (CME) associated with an X-class flare whose initiation is clearly observed in the low corona with high-cadence, high-resolution EUV images, providing us a rare opportunity to witness the early evolution of an energetic CME in detail. The eruption starts with a slow expansion of cool overlying loops (∼1 MK) following a jet-like event in the periphery of the active region. Underneath the expanding loop system, a reverse S-shaped dimming is seen immediately above the brightening active region in hot EUV passbands. The dimming is associated with a rising diffuse arch (∼6 MK), which wemore » interpret as a preexistent, high-lying flux rope. This is followed by the arising of a double hot channel (∼10 MK) from the core of the active region. The higher structures rise earlier and faster than lower ones, with the leading front undergoing extremely rapid acceleration up to 35 km s{sup –2}. This suggests that the torus instability is the major eruption mechanism and that it is the high-lying flux rope rather than the hot channels that drives the eruption. The compression of coronal plasmas skirting and overlying the expanding loop system, whose aspect ratio h/r increases with time as a result of the rapid upward acceleration, plays a significant role in driving an outward-propagating global EUV wave and a sunward-propagating local EUV wave, respectively.« less

Adolescent prescription ADHD medication abuse is rising along with prescriptions for these medications.

PubMed

Setlik, Jennifer; Bond, G Randall; Ho, Mona

2009-09-01

We sought to better understand the trend for prescription attention-deficit/hyperactivity disorder (ADHD) medication abuse by teenagers. We queried the American Association of Poison Control Center's National Poison Data System for the years of 1998-2005 for all cases involving people aged 13 to 19 years, for which the reason was intentional abuse or intentional misuse and the substance was a prescription medication used for ADHD treatment. For trend comparison, we sought data on the total number of exposures. In addition, we used teen and preteen ADHD medication sales data from IMS Health's National Disease and Therapeutic Index database to compare poison center call trends with likely availability. Calls related to teenaged victims of prescription ADHD medication abuse rose 76%, which is faster than calls for victims of substance abuse generally and teen substance abuse. The annual rate of total and teen exposures was unchanged. Over the 8 years, estimated prescriptions for teenagers and preteenagers increased 133% for amphetamine products, 52% for methylphenidate products, and 80% for both together. Reports of exposure to methylphenidate fell from 78% to 30%, whereas methylphenidate as a percentage of ADHD prescriptions decreased from 66% to 56%. Substance-related abuse calls per million adolescent prescriptions rose 140%. The sharp increase, out of proportion to other poison center calls, suggests a rising problem with teen ADHD stimulant medication abuse. Case severity increased over time. Sales data of ADHD medications suggest that the use and call-volume increase reflects availability, but the increase disproportionately involves amphetamines.

Will fluctuations in salt marsh–mangrove dominance alter vulnerability of a subtropical wetland to sea‐level rise?

USGS Publications Warehouse

Mckee, Karen L.; Vervaeke, William

2018-01-01

To avoid submergence during sea-level rise, coastal wetlands build soil surfaces vertically through accumulation of inorganic sediment and organic matter. At climatic boundaries where mangroves are expanding and replacing salt marsh, wetland capacity to respond to sea-level rise may change. To compare how well mangroves and salt marshes accommodate sea-level rise, we conducted a manipulative field experiment in a subtropical plant community in the subsiding Mississippi River Delta. Experimental plots were established in spatially equivalent positions along creek banks in monospecific stands of Spartina alterniflora (smooth cordgrass) or Avicennia germinans (black mangrove) and in mixed stands containing both species. To examine the effect of disturbance on elevation dynamics, vegetation in half of the plots was subjected to freezing (mangrove) or wrack burial (salt marsh), which caused shoot mortality. Vertical soil development was monitored for 6 years with the surface elevation table-marker horizon system. Comparison of land movement with relative sea-level rise showed that this plant community was experiencing an elevation deficit (i.e., sea level was rising faster than the wetland was building vertically) and was relying on elevation capital (i.e., relative position in the tidal frame) to survive. Although Avicennia plots had more elevation capital, suggesting longer survival, than Spartina or mixed plots, vegetation type had no effect on rates of accretion, vertical movement in root and sub-root zones, or net elevation change. Thus, these salt marsh and mangrove assemblages were accreting sediment and building vertically at equivalent rates. Small-scale disturbance of the plant canopy also had no effect on elevation trajectories—contrary to work in peat-forming wetlands showing elevation responses to changes in plant productivity. The findings indicate that in this deltaic setting with strong physical influences controlling elevation (sediment accretion, subsidence), mangrove replacement of salt marsh, with or without disturbance, will not necessarily alter vulnerability to sea-level rise.

Late Holocene sea- and land-level change on the U.S. southeastern Atlantic Coast

USGS Publications Warehouse

Kemp, Andrew C.; Bernhardt, Christopher E.; Horton, Benjamin P.; Kopp, Robert E.; Vane, Christopher H.; Peltier, W. Richard; Hawkes, Andrea D.; Donnelly, Jeffrey P.; Parnell, Andrew C.; Cahill, Niamh

2015-01-01

Late Holocene relative sea-level (RSL) reconstructions can be used to estimate rates of land-level (subsidence or uplift) change and therefore to modify global sea-level projections for regional conditions. These reconstructions also provide the long-term benchmark against which modern trends are compared and an opportunity to understand the response of sea level to past climate variability. To address a spatial absence of late Holocene data in Florida and Georgia, we reconstructed ~ 1.3 m of RSL rise in northeastern Florida (USA) during the past ~ 2600 years using plant remains and foraminifera in a dated core of high salt-marsh sediment. The reconstruction was fused with tide-gauge data from nearby Fernandina Beach, which measured 1.91 ± 0.26 mm/year of RSL rise since 1900 CE. The average rate of RSL rise prior to 1800 CE was 0.41 ± 0.08 mm/year. Assuming negligible change in global mean sea level from meltwater input/removal and thermal expansion/contraction, this sea-level history approximates net land-level (subsidence and geoid) change, principally from glacio-isostatic adjustment. Historic rates of rise commenced at 1850–1890 CE and it is virtually certain (P = 0.99) that the average rate of 20th century RSL rise in northeastern Florida was faster than during any of the preceding 26 centuries. The linearity of RSL rise in Florida is in contrast to the variability reconstructed at sites further north on the U.S. Atlantic coast and may suggest a role for ocean dynamic effects in explaining these more variable RSL reconstructions. Comparison of the difference between reconstructed rates of late Holocene RSL rise and historic trends measured by tide gauges indicates that 20th century sea-level trends along the U.S. Atlantic coast were not dominated by the characteristic spatial fingerprint of melting of the Greenland Ice Sheet.

Nitric oxide density measurements in air and air/fuel nanosecond pulse discharges by laser induced fluorescence

NASA Astrophysics Data System (ADS)

Uddi, M.; Jiang, N.; Adamovich, I. V.; Lempert, W. R.

2009-04-01

Laser induced fluorescence is used to measure absolute nitric oxide concentrations in air, methane-air and ethylene-air non-equilibrium plasmas, as a function of time after initiation of a single pulse, 20 kV peak voltage, 25 ns pulse duration discharge. A mixture of NO and nitrogen with known composition (4.18 ppm NO) is used for calibration. Peak NO density in air at 60 Torr, after a single pulse, is ~8 × 1012 cm-3 (~4.14 ppm) occurring at ~250 µs after the pulse, with decay time of ~16.5 ms. Peak NO atom mole fraction in a methane-air mixture with equivalence ratio of phiv = 0.5 is found to be approximately equal to that in air, with approximately the same rise and decay rate. In an ethylene-air mixture (also with equivalence ratio of phiv = 0.5), the rise and decay times are comparable to air and methane-air, but the peak NO concentration is reduced by a factor of approximately 2.5. Spontaneous emission measurements show that excited electronic states N2(C 3Π) and NO(A 2Σ) in air at P = 60 Torr decay within ~20 ns and ~1 µs, respectively. Kinetic modelling calculations incorporating air plasma kinetics complemented with the GRI Mech 3.0 hydrocarbon oxidation mechanism are compared with the experimental data using three different NO production mechanisms. It is found that NO concentration rise after the discharge pulse is much faster than predicted by Zel'dovich mechanism reactions, by two orders of magnitude, but much slower compared with reactions of electronically excited nitrogen atoms and molecules, also by two orders of magnitude. It is concluded that processes involving long lifetime (~100 µs) metastable states, such as N2(X 1Σ,v) and O2(b 1Σ), formed by quenching of the metastable N2(A 3Σ) state by ground electronic state O2, may play a dominant role in NO formation. NO decay, in all cases, is found to be dominated by the reverse Zel'dovich reaction, NO + O → N + O2, as well as by conversion into NO2 in a reaction of NO with ozone.

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers

PubMed Central

Parry, Dave; Cooper, Chris E.

2018-01-01

The development of an underwater near-infrared spectroscopy (uNIRS) device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i) to trial the use of uNIRS, in a real world training study, and (ii) to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repeated swim sprint test before and after an eight week endurance training program. A waterproof, portable Near-Infrared Spectroscopy device was attached to the vastus lateralis. uNIRS successfully measured changes in muscle oxygenation and blood volume in all individuals; rapid sub-second time resolution of the device was able to demonstrate muscle oxygenation changes during the characteristic swim movements. Post training heart rate recovery and swim performance time were significantly improved. uNIRS data also showed significant changes. A larger rise in deoxyhemoglobin during individual sprints suggested training induced an increase in muscle oxygen extraction; a faster recovery time for muscle oxygenation suggested positive training induced changes and significant changes in muscle blood flow also occur. As a strong correlation was seen between an increased reoxygenation rate and an improved swim performance time, these findings support the use of uNIRS as a new performance analysis tool in swimming. PMID:29692951

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers.

PubMed

Jones, Ben; Parry, Dave; Cooper, Chris E

2018-01-01

The development of an underwater near-infrared spectroscopy (uNIRS) device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i) to trial the use of uNIRS, in a real world training study, and (ii) to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repeated swim sprint test before and after an eight week endurance training program. A waterproof, portable Near-Infrared Spectroscopy device was attached to the vastus lateralis . uNIRS successfully measured changes in muscle oxygenation and blood volume in all individuals; rapid sub-second time resolution of the device was able to demonstrate muscle oxygenation changes during the characteristic swim movements. Post training heart rate recovery and swim performance time were significantly improved. uNIRS data also showed significant changes. A larger rise in deoxyhemoglobin during individual sprints suggested training induced an increase in muscle oxygen extraction; a faster recovery time for muscle oxygenation suggested positive training induced changes and significant changes in muscle blood flow also occur. As a strong correlation was seen between an increased reoxygenation rate and an improved swim performance time, these findings support the use of uNIRS as a new performance analysis tool in swimming.

Earlier time to aerobic exercise is associated with faster recovery following acute sport concussion

PubMed Central

Richards, Doug; Comper, Paul; Hutchison, Michael G.

2018-01-01

Objective To determine whether earlier time to initiation of aerobic exercise following acute concussion is associated with time to full return to (1) sport and (2) school or work. Methods A retrospective stratified propensity score survival analysis of acute (≤14 days) concussion was used to determine whether time (days) to initiation of aerobic exercise post-concussion was associated with, both, time (days) to full return to (1) sport and (2) school or work. Results A total of 253 acute concussions [median (IQR) age, 17.0 (15.0–20.0) years; 148 (58.5%) males] were included in this study. Multivariate Cox regression models identified that earlier time to aerobic exercise was associated with faster return to sport and school/work adjusting for other covariates, including quintile propensity strata. For each successive day in delay to initiation of aerobic exercise, individuals had a less favourable recovery trajectory. Initiating aerobic exercise at 3 and 7 days following injury was associated with a respective 36.5% (HR, 0.63; 95% CI, 0.53–0.76) and 73.2% (HR, 0.27; 95% CI, 0.16–0.45) reduced probability of faster full return to sport compared to within 1 day; and a respective 45.9% (HR, 0.54; 95% CI, 0.44–0.66) and 83.1% (HR, 0.17; 95% CI, 0.10–0.30) reduced probability of faster full return to school/work. Additionally, concussion history, symptom severity, LOC deleteriously influenced concussion recovery. Conclusion Earlier initiation of aerobic exercise was associated with faster full return to sport and school or work. This study provides greater insight into the benefits and safety of aerobic exercise within the first week of the injury. PMID:29668716

Earlier time to aerobic exercise is associated with faster recovery following acute sport concussion.

PubMed

Lawrence, David Wyndham; Richards, Doug; Comper, Paul; Hutchison, Michael G

2018-01-01

To determine whether earlier time to initiation of aerobic exercise following acute concussion is associated with time to full return to (1) sport and (2) school or work. A retrospective stratified propensity score survival analysis of acute (≤14 days) concussion was used to determine whether time (days) to initiation of aerobic exercise post-concussion was associated with, both, time (days) to full return to (1) sport and (2) school or work. A total of 253 acute concussions [median (IQR) age, 17.0 (15.0-20.0) years; 148 (58.5%) males] were included in this study. Multivariate Cox regression models identified that earlier time to aerobic exercise was associated with faster return to sport and school/work adjusting for other covariates, including quintile propensity strata. For each successive day in delay to initiation of aerobic exercise, individuals had a less favourable recovery trajectory. Initiating aerobic exercise at 3 and 7 days following injury was associated with a respective 36.5% (HR, 0.63; 95% CI, 0.53-0.76) and 73.2% (HR, 0.27; 95% CI, 0.16-0.45) reduced probability of faster full return to sport compared to within 1 day; and a respective 45.9% (HR, 0.54; 95% CI, 0.44-0.66) and 83.1% (HR, 0.17; 95% CI, 0.10-0.30) reduced probability of faster full return to school/work. Additionally, concussion history, symptom severity, LOC deleteriously influenced concussion recovery. Earlier initiation of aerobic exercise was associated with faster full return to sport and school or work. This study provides greater insight into the benefits and safety of aerobic exercise within the first week of the injury.

Withholding response to self-face is faster than to other-face.

PubMed

Zhu, Min; Hu, Yinying; Tang, Xiaochen; Luo, Junlong; Gao, Xiangping

2015-01-01

Self-face advantage refers to adults' response to self-face is faster than that to other-face. A stop-signal task was used to explore how self-face advantage interacted with response inhibition. The results showed that reaction times of self-face were faster than that of other-face not in the go task but in the stop response trials. The novelty of the finding was that self-face has shorter stop-signal reaction time compared to other-face in the successful inhibition trials. These results indicated the processing mechanism of self-face may be characterized by a strong response tendency and a corresponding strong inhibition control.

Kraken: ultrafast metagenomic sequence classification using exact alignments

PubMed Central

2014-01-01

Kraken is an ultrafast and highly accurate program for assigning taxonomic labels to metagenomic DNA sequences. Previous programs designed for this task have been relatively slow and computationally expensive, forcing researchers to use faster abundance estimation programs, which only classify small subsets of metagenomic data. Using exact alignment of k-mers, Kraken achieves classification accuracy comparable to the fastest BLAST program. In its fastest mode, Kraken classifies 100 base pair reads at a rate of over 4.1 million reads per minute, 909 times faster than Megablast and 11 times faster than the abundance estimation program MetaPhlAn. Kraken is available at http://ccb.jhu.edu/software/kraken/. PMID:24580807

Enabling Near Real-Time Remote Search for Fast Transient Events with Lossy Data Compression

NASA Astrophysics Data System (ADS)

Vohl, Dany; Pritchard, Tyler; Andreoni, Igor; Cooke, Jeffrey; Meade, Bernard

2017-09-01

We present a systematic evaluation of JPEG2000 (ISO/IEC 15444) as a transport data format to enable rapid remote searches for fast transient events as part of the Deeper Wider Faster programme. Deeper Wider Faster programme uses 20 telescopes from radio to gamma rays to perform simultaneous and rapid-response follow-up searches for fast transient events on millisecond-to-hours timescales. Deeper Wider Faster programme search demands have a set of constraints that is becoming common amongst large collaborations. Here, we focus on the rapid optical data component of Deeper Wider Faster programme led by the Dark Energy Camera at Cerro Tololo Inter-American Observatory. Each Dark Energy Camera image has 70 total coupled-charged devices saved as a 1.2 gigabyte FITS file. Near real-time data processing and fast transient candidate identifications-in minutes for rapid follow-up triggers on other telescopes-requires computational power exceeding what is currently available on-site at Cerro Tololo Inter-American Observatory. In this context, data files need to be transmitted rapidly to a foreign location for supercomputing post-processing, source finding, visualisation and analysis. This step in the search process poses a major bottleneck, and reducing the data size helps accommodate faster data transmission. To maximise our gain in transfer time and still achieve our science goals, we opt for lossy data compression-keeping in mind that raw data is archived and can be evaluated at a later time. We evaluate how lossy JPEG2000 compression affects the process of finding transients, and find only a negligible effect for compression ratios up to 25:1. We also find a linear relation between compression ratio and the mean estimated data transmission speed-up factor. Adding highly customised compression and decompression steps to the science pipeline considerably reduces the transmission time-validating its introduction to the Deeper Wider Faster programme science pipeline and enabling science that was otherwise too difficult with current technology.

Role of climate change in reforestation and nursery practices

Treesearch

Mary I. Williams; R. Kasten Dumroese

2014-01-01

Ecosystems have been adjusting to changes in climate over time, but projections are that future global climate will change at rates faster than that previously experienced in geologic time. It is not necessarily the amount of change, but rather this rate of change that is most threatening to plant species - the climate appears to be changing faster than plants can...

How Has Internet Use Changed between 2012 and 2015? PISA in Focus No. 83

ERIC Educational Resources Information Center

Echazarra, Alfonso

2018-01-01

In the growing world of digital technology everything is about speed: computer processors have doubled their performance every two years for decades; the future 5G mobile phone generation is predicted to be about 100 times faster than the current 4G and 20 000 times faster than the "ancient" 3G; and, according to the International…

Ultrafast exciton dynamics in cadmium selenide nanocrystals determined by femtosecond fluorescence upconversion spectroscopy

NASA Astrophysics Data System (ADS)

Underwood, David Frederick

Femtosecond fluorescence upconversion spectroscopy is a technique that allows the unambiguous determination of the excited state dynamics of an analyte. Combining this method with the use of tunable laser excitation, the exciton dynamics in semiconducting nanocrystals (NC's) of cadmium selenide (CdSe) have been determined, devoid of the complications arising from more common spectroscopic methods such as pump-probe. The results of this investigation were used to construct a model to fully describe the three-level system comprising of the valence and conduction bands and surface states, which have been calculated by others to lie mid-gap in energy. Smaller NC's showed faster decay components due to increased interaction between the exciton and surface states. The deep trap emission, which has never before been measured by ultrafast fluorescence techniques, shows a rapid rise time (˜2 ps), which is attributed to surface selenium dangling bonds relaxing to the valence band and radiatively combining with the photo-generated hole. The band edge fluorescence decays as the deep trap emission grows in, inherently coupling the two processes. An experiment which measured the dependence of the excitation energy showed that increased energy imparted to the NC's resulted in increased rise times, yielding the timescales for exciton relaxation through the valence and conduction band states to the lowest emitting state. Surface-oxidized and normally-passivated NC's display the same decay dynamics in time but differ in relative amplitude; the latter point agrees with steady-state measurements. The rotational anisotrophy of the NC's was measured and agrees with previous pump-probe data. Upconversion on the red and blue sides of the static fluorescence spectrum showed no discernable differences, which is either and inherent limitation of the experimental apparatus, or the possibility that lower-lying triplet states are populated on a timescale below the instrument resolution.

BOLD temporal dynamics of rat superior colliculus and lateral geniculate nucleus following short duration visual stimulation.

PubMed

Lau, Condon; Zhou, Iris Y; Cheung, Matthew M; Chan, Kevin C; Wu, Ed X

2011-04-29

The superior colliculus (SC) and lateral geniculate nucleus (LGN) are important subcortical structures for vision. Much of our understanding of vision was obtained using invasive and small field of view (FOV) techniques. In this study, we use non-invasive, large FOV blood oxygenation level-dependent (BOLD) fMRI to measure the SC and LGN's response temporal dynamics following short duration (1 s) visual stimulation. Experiments are performed at 7 tesla on Sprague Dawley rats stimulated in one eye with flashing light. Gradient-echo and spin-echo sequences are used to provide complementary information. An anatomical image is acquired from one rat after injection of monocrystalline iron oxide nanoparticles (MION), a blood vessel contrast agent. BOLD responses are concentrated in the contralateral SC and LGN. The SC BOLD signal measured with gradient-echo rises to 50% of maximum amplitude (PEAK) 0.2±0.2 s before the LGN signal (p<0.05). The LGN signal returns to 50% of PEAK 1.4±1.2 s before the SC signal (p<0.05). These results indicate the SC signal rises faster than the LGN signal but settles slower. Spin-echo results support these findings. The post-MION image shows the SC and LGN lie beneath large blood vessels. This subcortical vasculature is similar to that in the cortex, which also lies beneath large vessels. The LGN lies closer to the large vessels than much of the SC. The differences in response timing between SC and LGN are very similar to those between deep and shallow cortical layers following electrical stimulation, which are related to depth-dependent blood vessel dilation rates. This combined with the similarities in vasculature between subcortex and cortex suggest the SC and LGN timing differences are also related to depth-dependent dilation rates. This study shows for the first time that BOLD responses in the rat SC and LGN following short duration visual stimulation are temporally different.

Nutritional quality and marketing strategies of fast food children's combo meals in Guatemala.

PubMed

Mazariegos, Sofia; Chacón, Violeta; Cole, Adam; Barnoya, Joaquin

2016-01-01

Overweight and obesity prevalence in children is now on the rise in low/middle-income countries, including Guatemala. Fast food consumption is a recognized contributing factor to this rise. Fast food restaurants use health claims, toy giveaways, price incentives and fast service to promote children's combo meals. This study sought to assess the use of toy giveaways, time to delivery and price incentives as marketing strategies in fast food chain restaurants in Guatemala. In addition, we sought to compare nutritional quality of combo meals with and without health claims. We visited one restaurant from each of the 8 major fast food chains in Guatemala and purchased all children's combo meals to assess the prevalence of toy giveaways, health claims, and difference in delivery time and price between the combo meal and each meal item purchased separately. Each item was then classified as "healthy" or "less healthy" using the UK Nutrition Profile Model. Nutrition information was collected on-site, from the restaurant website, or by calling the customer service phone number. We found 114 combo meals, 21 (18.4%) of which were children's combo meals. Five (24%) had nutrition information, all were classified by our analysis as "less healthy", and three had a health claim. On average, combo meals were US$1.93 less expensive than purchasing children's meal items individually ( p  = 0.01). Time to delivery was 1.44 min faster for combo meals compared to purchasing meal items individually ( p  = 0.19). Children's fast food combo meals in Guatemala were promoted using several marketing strategies that encourage consumption, including offering toy giveaways and price incentives. In addition, nutrition information is lacking in fast food chain restaurants. Public health advocates in Guatemala should consider a comprehensive approach to encourage healthier choices within fast food restaurants including policies that require fruit and vegetable options for meal side dishes, accessible and easy to read nutrition information, and restrict the use of toy giveaways.

Time and tide: examining the potential for sediment delivery to a heavily modified tidal delta plain

NASA Astrophysics Data System (ADS)

Hale, R. P.; Goodbred, S. L., Jr.; Bain, R. L.; Wilson, C.

2016-02-01

In SW Bangladesh, man-made barriers ("polders") built since the 1960s to protect agricultural resources from seasonal flooding have drastically altered delta-plain dynamics. With the link between tidal channels and the delta plain destroyed and no pathway for the delivery of new sediment, compaction, tectonic subsidence, and global sea-level rise have resulted in a scenario where much of the land surface behind the barriers sits 1.5 m below mean sea level. In the adjacent the Sundarbans National Forest (SNF), the lack of polders has allowed for sediment deposition during spring high tides, and sedimentation rates on the delta plain have kept pace with local sea level rise. Recent research has demonstrated the potential for rapid sedimentation in the inhabited areas following polder damage or destruction (Auerbach et al., 2015). These authors observed 40 cm/yr accumulation rates inside the poldered area following bank failures associated with a typhoon, and no obvious seasonality associated with the deposits. Preliminary research from within SNF, however, suggests that the accumulation rates are slightly faster during then monsoon (1.0-2.0 cm/yr) than the dry season (0.2-1.4 cm/yr). In this study, we address seasonal differences through a comparison of tidal elevations and suspended sediment concentrations (SSC) across tidal ranges and seasons, in both the SNF, and the tidal channels adjacent to the poldered region (PR). Water velocity appears to be the primary control on SSC, and there is no obvious seasonal variability in maximum observed SSC (PR: 0.1-0.8 g/l; SNF: 0.01-0.35 g/l). Peak tidal elevations remain unchanged across seasons, however the time of delta plain inundation time increases during the monsoon, which might control seasonal accumulation rates. Understanding more about this seasonal variability will be critical for future engineering and policy decisions surrounding how to best mitigate and manage land loss in the PR going forward.

Sensitivity analysis of hydrogeological parameters affecting groundwater storage change caused by sea level rise

NASA Astrophysics Data System (ADS)

Shin, J.; Kim, K.-H.; Lee, K.-K.

2012-04-01

Sea level rise, which is one of the representative phenomena of climate changes caused by global warming, can affect groundwater system. The rising trend of the sea level caused by the global warming is reported to be about 3 mm/year for the most recent 10 year average (IPCC, 2007). The rate of sea level rise around the Korean peninsula is reported to be 2.30±2.22 mm/yr during the 1960-1999 period (Cho, 2002) and 2.16±1.77 mm/yr (Kim et al., 2009) during the 1968-2007 period. Both of these rates are faster than the 1.8±0.5 mm/yr global average for the similar 1961-2003 period (IPCC, 2007). In this study, we analyzed changes in the groundwater environment affected by the sea level rise by using an analytical methodology. We tried to find the most effective parameters of groundwater amount change in order to estimate the change in fresh water amount in coastal groundwater. A hypothetical island model of a cylindrical shape in considered. The groundwater storage change is bi-directional as the sea level rises according to the natural and hydrogeological conditions. Analysis of the computation results shows that topographic slope and hydraulic conductivity are the most sensitive factors. The contributions of the groundwater recharge rate and the thickness of aquifer below sea level are relatively less effective. In the island with steep seashore slopes larger than 1~2 degrees or so, the storage amount of fresh water in a coastal area increases as sea level rises. On the other hand, when sea level drops, the storage amount decreases. This is because the groundwater level also rises with the rising sea level in steep seashores. For relatively flat seashores, where the slope is smaller than around 1-2 degrees, the storage amount of coastal fresh water decreases when the sea level rises because the area flooded by the rising sea water is increased. The volume of aquifer fresh water in this circumstance is greatly reduced in proportion to the flooded area with the sea level rising. Since relatively flat seashores where the slope is less than 1-2 degrees are much more common in Korea, it is expected that the quantity of fresh groundwater storage in most of the coastal region in Korea will be greatly reduced with sea level rise. Acknowledgement: This study is financially supported by BK21.

Functional effects of treadmill-based gait training at faster speeds in stroke survivors: a prospective, single-group study.

PubMed

Mohammadi, Roghayeh; Ershad, Navid; Rezayinejad, Marziyeh; Fatemi, Elham; Phadke, Chetan P

2017-09-01

To examine the functional effects of walking retraining at faster than self-selected speed (SSS). Ten individuals with chronic stroke participated in a 4-week training over a treadmill at walking speeds 40% faster than SSS, three times per week, 30 min/session. Outcome measures assessed before, after, and 2 months after the end of intervention were the Timed Up and Go, the 6-Minute Walk, the 10-Meter Walk test, the Modified Ashworth Scale, SSS, and fastest comfortable speed. After 4 weeks of training, all outcome measures showed clinically meaningful and statistically significant improvements (P<0.05) that were maintained at 2 months after the end of the training. The results showed that a strategy of training at a speed 40% faster than SSS can improve functional activity in individuals with chronic stroke, with effects lasting up to 2 months after the intervention.

Rapid rise predicted for geologist salaries

NASA Astrophysics Data System (ADS)

The number of geologists entering the earth science profession and their average salary will increase faster than for other natural and physical sciences during the next 2 decades, according to A.G. Unklesbay, executive director of the American Geological Institute (AGI). He is drafting for the National Academy of Sciences' Geological Sciences Board (Eos, 62, p. 107, March 17) a chapter on manpower needs in geology.‘AGI studies trends in geoscience education, and our records show that majors have doubled in the decade 1971-1980,’ Unklesbay said. ‘These studies are ongoing and the data for 1981 show this trend continuing.’

The role and challenges of the food industry in addressing chronic disease

PubMed Central

2010-01-01

Summary Increasingly, food companies play an important role in stemming the rising burden of nutrition-related chronic diseases. Concrete actions taken by these companies include global public commitments to address food reformulation, consumer information, responsible marketing, promotion of healthy lifestyles, and public-private partnerships. These actions are reviewed together with eleven specific PepsiCo goals and commitments that address products, the marketplace, and communities at large. Interim progress on these goals and commitments are discussed as well as constraints hampering faster progress. Further disease prevention depends on increasing implementation of private-public initiatives. PMID:20509876

United States Air Force Research Initiation Program. 1984 Research Reports. Volume 1.

DTIC Science & Technology

1986-05-01

storage , several 8" floppy disk drives were substituteu; to gain the equivalent speed, an 8088 microprocessor faster than the Intel version and a 2-wegabyte... RAil .. cnory and ram-drive software were substituted. 2. Not included above is one item which was listed in the RISE proposal budget (the Z-204...FUSOIONCAL/JM. 280 REM C4IHEAT CAPACITYiCAL/GM-K. 2,90 C=0.46 00’ REM E1=ACTIVATION ENERGYiCAL /MOL. 3 2’ REM R-GAS CONSTANTiCAL/MOL-K. F!’ = 1. 9 B37 .* 3

Mind the Gap: High Unmet Financial Need Threatens Persistence and Completion for Low-Income Community College Students

ERIC Educational Resources Information Center

Choitz, Vickie; Reimherr, Patrick

2013-01-01

Over the last three decades, college tuition and fees have increased nearly four times faster than median income and four-and-a-half times faster than inflation. The rapid increase in college costs and flat or reduced funding in student aid has resulted in sizable "unmet need" and has forced students-- particularly low-income students--to borrow…

Early effects of Lansoprazole orally disintegrating tablets on intragastric pH in CYP2C19 extensive metabolizers

PubMed Central

Yamagishi, Hatsushi; Koike, Tomoyuki; Ohara, Shuichi; Horii, Toru; Kikuchi, Ryousuke; Kobayashi, Shigeyuki; Abe, Yasuhiko; Iijima, Katsunori; Imatani, Akira; Suzuki, Kaori; Hishinuma, Takanori; Goto, Junichi; Shimosegawa, Tooru

2008-01-01

AIM: To compare rabeprazole (RPZ; 10 mg) with Lansoprazole orally disintegrating tablets (LPZ; 30 mg OD) in terms of antisecretory activity and blood drug concentration after a single dose. METHODS: Eight H pylori-negative cytochrome P450 (CYP) 2C19 extensive metabolizers were assigned to receive a single oral dose of RPZ 10 mg or LPZ 30 mg OD. Twelve hour intragastric pH monitoring was performed on the day of treatment. Blood samples were also collected after the administration of each drug. RESULTS: LPZ 30 mg OD induced a significantly earlier rise in blood drug concentration than RPZ 10 mg; consequently, LPZ 30 mg OD induced a significantly earlier rise in median pH in the third and fourth hours of the study. CONCLUSION: In H pylori-negative CYP2C19 extensive metabolizers, LPZ 30 mg OD induced a significantly faster inhibition of gastric acid secretion than RPZ 10 mg. PMID:18395905

Temperature and Snowfall in Western Queen Maud Land Increasing Faster Than Climate Model Projections

NASA Astrophysics Data System (ADS)

Medley, B.; McConnell, J. R.; Neumann, T. A.; Reijmer, C. H.; Chellman, N.; Sigl, M.; Kipfstuhl, S.

2018-02-01

East Antarctic Ice Sheet (EAIS) mass balance is largely driven by snowfall. Recently, increased snowfall in Queen Maud Land led to years of EAIS mass gain. It is difficult to determine whether these years of enhanced snowfall are anomalous or part of a longer-term trend, reducing our ability to assess the mitigating impact of snowfall on sea level rise. We determine that the recent snowfall increases in western Queen Maud Land (QML) are part of a long-term trend (+5.2 ± 3.7% decade-1) and are unprecedented over the past two millennia. Warming between 1998 and 2016 is significant and rapid (+1.1 ± 0.7°C decade-1). Using these observations, we determine that the current accumulation and temperature increases in QML from an ensemble of global climate simulations are too low, which suggests that projections of the QML contribution to sea level rise are potentially overestimated with a reduced mitigating impact of enhanced snowfall in a warming world.

Temperature and Snowfall in Western Queen Maud Land Increasing Faster than Climate Model Projections

NASA Technical Reports Server (NTRS)

Medley, B.; McConnell, J. R.; Neumann, T. A.; Reijmer, C. H.; Chellman, N.; Sigl, M.; Kipfstuhl, S.

2017-01-01

East Antarctic Ice Sheet (EAIS) mass balance is largely driven by snowfall. Recently, increased snowfall in Queen Maud Land led to years of EAIS mass gain. It is difficult to determine whether these years of enhanced snowfall are anomalous or part of a longer-term trend, reducing our ability to assess the mitigating impact of snowfall on sea level rise. We determine that the recent snowfall increases in western Queen Maud Land (QML) are part of a long-term trend (+5.2 +/- 3.7% decade(exp -1)) and are unprecedented over the past two millennia. Warming between 1998 and 2016 is significant and rapid (+1.1 +/- 0.7 C decade(exp -1)). Using these observations, we determine that the current accumulation and temperature increases in QML from an ensemble of global climate simulations are too low, which suggests that projections of the QML contribution to sea level rise are potentially overestimated with a reduced mitigating impact of enhanced snowfall in a warming world.

Cell-Specific Activity-Dependent Fractionation of Layer 2/3→5B Excitatory Signaling in Mouse Auditory Cortex

PubMed Central

Joshi, Ankur; Middleton, Jason W.; Anderson, Charles T.; Borges, Katharine; Suter, Benjamin A.; Shepherd, Gordon M. G.

2015-01-01

Auditory cortex (AC) layer 5B (L5B) contains both corticocollicular neurons, a type of pyramidal-tract neuron projecting to the inferior colliculus, and corticocallosal neurons, a type of intratelencephalic neuron projecting to contralateral AC. Although it is known that these neuronal types have distinct roles in auditory processing and different response properties to sound, the synaptic and intrinsic mechanisms shaping their input–output functions remain less understood. Here, we recorded in brain slices of mouse AC from retrogradely labeled corticocollicular and neighboring corticocallosal neurons in L5B. Corticocollicular neurons had, on average, lower input resistance, greater hyperpolarization-activated current (Ih), depolarized resting membrane potential, faster action potentials, initial spike doublets, and less spike-frequency adaptation. In paired recordings between single L2/3 and labeled L5B neurons, the probabilities of connection, amplitude, latency, rise time, and decay time constant of the unitary EPSC were not different for L2/3→corticocollicular and L2/3→corticocallosal connections. However, short trains of unitary EPSCs showed no synaptic depression in L2/3→corticocollicular connections, but substantial depression in L2/3→corticocallosal connections. Synaptic potentials in L2/3→corticocollicular connections decayed faster and showed less temporal summation, consistent with increased Ih in corticocollicular neurons, whereas synaptic potentials in L2/3→corticocallosal connections showed more temporal summation. Extracellular L2/3 stimulation at two different rates resulted in spiking in L5B neurons; for corticocallosal neurons the spike rate was frequency dependent, but for corticocollicular neurons it was not. Together, these findings identify cell-specific intrinsic and synaptic mechanisms that divide intracortical synaptic excitation from L2/3 to L5B into two functionally distinct pathways with different input–output functions. PMID:25698747

Bacterial trajectories tracked with time-lapse video-microscopy reveal the impact of manganese biomineralization on bacterial sedimentation.

NASA Astrophysics Data System (ADS)

Kerboas, Camille; Pena, Jasquelin; De Anna, Pietro

2017-04-01

In aquatic and subsurface environments, sedimentation may influence bacterial transport. Microorganisms that carry out biomineralization reactions may exhibit distinct transport properties from non-biomineralizing organisms due an apparent increase in density caused by biomineral production. For several decades, the biomineralization of manganese (Mn) has been recognized to be a major environmental process, whereby Mn oxide (MnO2(s)) minerals participate in a plethora of biogeochemical processes including contaminant adsorption, organic matter oxidation. Typically, manganese biomineralization proceeds through the enzymatic oxidation of aqueous Mn2+ to Mn4+ and precipitation of MnO2(s) in a biofilm matrix outside the bacterial cell. Here, we present a study of the impact of biomineralization on the sedimentation properties of bacteria at small scales (over mm distances) under hydrostatic conditions. We hypothesize that bacteria will sediment faster when biomineralization is active due to encrustation of the organisms by mineral particles. To test this hypothesis, we tracked the vertical notion of individual bacteria (Pseudomonas putida GB-1) using time-lapse video-microscopy. We compared the sedimentation velocity of bacteria in the case where significant biomineralization had occurred, as inferred from bulk measurements of solid phase Mn, with the sinking velocity of bacteria grown without Mn. We calibrated the proposed method by comparing velocity measurements of sinking polystyrene micro-sphere of known density and size with Stokes law, obtaining results that were accurate within 1% of the theoretical value (29.4 nm/s). We also measured a diffusion coefficient of 7x10-13 m2/s for the particles. Following this approach, we measured the sedimentation velocity of P. putida with and without MnO2(s). Our results show that biomineralization leads to faster sedimentation of the bacteria. In natural environments, biomineralization reactions may increase the sinking velocity of bacteria and therefore contribute to the physical separation of organisms according to phenotype and give rise to localized spots of high mineralization rates.

Letter-case information and the identification of brand names.

PubMed

Perea, Manuel; Jiménez, María; Talero, Fernanda; López-Cañada, Soraya

2015-02-01

A central tenet of most current models of visual-word recognition is that lexical units are activated on the basis of case-invariant abstract letter representations. Here, we examined this assumption by using a unique type of words: brand names. The rationale of the experiments is that brand names are archetypically printed either in lowercase (e.g., adidas) or uppercase (e.g., IKEA). This allows us to present the brand names in their standard or non-standard case configuration (e.g., adidas, IKEA vs. ADIDAS, ikea, respectively). We conducted two experiments with a brand-decision task ('is it a brand name?'): a single-presentation experiment and a masked priming experiment. Results in the single-presentation experiment revealed faster identification times of brand names in their standard case configuration than in their non-standard case configuration (i.e., adidas faster than ADIDAS; IKEA faster than ikea). In the masked priming experiment, we found faster identification times of brand names when they were preceded by an identity prime that matched its standard case configuration than when it did not (i.e., faster response times to adidas-adidas than to ADIDAS-adidas). Taken together, the present findings strongly suggest that letter-case information forms part of a brand name's graphemic information, thus posing some limits to current models of visual-word recognition. © 2014 The British Psychological Society.

Transfer effects of manipulating temporal constraints on learning a two-choice reaction time task with low stimulus-response compatibility.

PubMed

Chen, David D; Pei, Laura; Chan, John S Y; Yan, Jin H

2012-10-01

Recent research using deliberate amplification of spatial errors to increase motor learning leads to the question of whether amplifying temporal errors may also facilitate learning. We investigated transfer effects caused by manipulating temporal constraints on learning a two-choice reaction time (CRT) task with varying degrees of stimulus-response compatibility. Thirty-four participants were randomly assigned to one of the three groups and completed 120 trials during acquisition. For every fourth trial, one group was instructed to decrease CRT by 50 msec. relative to the previous trial and a second group was instructed to increase CRT by 50 msec. The third group (the control) was told not to change their responses. After a 5-min. break, participants completed a 40-trial no-feedback transfer test. A 40-trial delayed transfer test was administered 24 hours later. During acquisition, the Decreased Reaction Time group responded faster than the two other groups, but this group also made more errors than the other two groups. In the 5-min. delayed test (immediate transfer), the Decreased Reaction Time group had faster reaction times than the other two groups, while for the 24-hr. delayed test (delayed transfer), both the Decreased Reaction Time group and Increased Reaction Time group had significantly faster reaction times than the control. For delayed transfer, both Decreased and Increased Reaction Time groups reacted significantly faster than the control group. Analyses of error scores in the transfer tests indicated revealed no significant group differences. Results were discussed with regard to the notion of practice variability and goal-setting benefits.

An ultrafast programmable electrical tester for enabling time-resolved, sub-nanosecond switching dynamics and programming of nanoscale memory devices.

PubMed

Shukla, Krishna Dayal; Saxena, Nishant; Manivannan, Anbarasu

2017-12-01

Recent advancements in commercialization of high-speed non-volatile electronic memories including phase change memory (PCM) have shown potential not only for advanced data storage but also for novel computing concepts. However, an in-depth understanding on ultrafast electrical switching dynamics is a key challenge for defining the ultimate speed of nanoscale memory devices that demands for an unconventional electrical setup, specifically capable of handling extremely fast electrical pulses. In the present work, an ultrafast programmable electrical tester (PET) setup has been developed exceptionally for unravelling time-resolved electrical switching dynamics and programming characteristics of nanoscale memory devices at the picosecond (ps) time scale. This setup consists of novel high-frequency contact-boards carefully designed to capture extremely fast switching transient characteristics within 200 ± 25 ps using time-resolved current-voltage measurements. All the instruments in the system are synchronized using LabVIEW, which helps to achieve various programming characteristics such as voltage-dependent transient parameters, read/write operations, and endurance test of memory devices systematically using short voltage pulses having pulse parameters varied from 1 ns rise/fall time and 1.5 ns pulse width (full width half maximum). Furthermore, the setup has successfully demonstrated strikingly one order faster switching characteristics of Ag 5 In 5 Sb 60 Te 30 (AIST) PCM devices within 250 ps. Hence, this novel electrical setup would be immensely helpful for realizing the ultimate speed limits of various high-speed memory technologies for future computing.

An ultrafast programmable electrical tester for enabling time-resolved, sub-nanosecond switching dynamics and programming of nanoscale memory devices

NASA Astrophysics Data System (ADS)

Shukla, Krishna Dayal; Saxena, Nishant; Manivannan, Anbarasu

2017-12-01

Recent advancements in commercialization of high-speed non-volatile electronic memories including phase change memory (PCM) have shown potential not only for advanced data storage but also for novel computing concepts. However, an in-depth understanding on ultrafast electrical switching dynamics is a key challenge for defining the ultimate speed of nanoscale memory devices that demands for an unconventional electrical setup, specifically capable of handling extremely fast electrical pulses. In the present work, an ultrafast programmable electrical tester (PET) setup has been developed exceptionally for unravelling time-resolved electrical switching dynamics and programming characteristics of nanoscale memory devices at the picosecond (ps) time scale. This setup consists of novel high-frequency contact-boards carefully designed to capture extremely fast switching transient characteristics within 200 ± 25 ps using time-resolved current-voltage measurements. All the instruments in the system are synchronized using LabVIEW, which helps to achieve various programming characteristics such as voltage-dependent transient parameters, read/write operations, and endurance test of memory devices systematically using short voltage pulses having pulse parameters varied from 1 ns rise/fall time and 1.5 ns pulse width (full width half maximum). Furthermore, the setup has successfully demonstrated strikingly one order faster switching characteristics of Ag5In5Sb60Te30 (AIST) PCM devices within 250 ps. Hence, this novel electrical setup would be immensely helpful for realizing the ultimate speed limits of various high-speed memory technologies for future computing.

An Adaptor Domain-Mediated Auto-Catalytic Interfacial Kinase Reaction

PubMed Central

Liao, Xiaoli; Su, Jing; Mrksich, Milan

2010-01-01

This paper describes a model system for studying the auto-catalytic phosphorylation of an immobilized substrate by a kinase enzyme. This work uses self-assembled monolayers (SAMs) of alkanethiolates on gold to present the peptide substrate on a planar surface. Treatment of the monolayer with Abl kinase results in phosphorylation of the substrate. The phosphorylated peptide then serves as a ligand for the SH2 adaptor domain of the kinase and thereby directs the kinase activity to nearby peptide substrates. This directed reaction is intramolecular and proceeds with a faster rate than does the initial, intermolecular reaction, making this an auto-catalytic process. The kinetic non-linearity gives rise to properties that have no counterpart in the corresponding homogeneous phase reaction: in one example, the rate for phosphorylation of a mixture of two peptides is faster than the sum of the rates for phosphorylation of each peptide when presented alone. This work highlights the use of an adaptor domain in modulating the activity of a kinase enzyme for an immobilized substrate and offers a new approach for studying biochemical reactions in spatially inhomogeneous settings. PMID:19821459

Population causes and consequences of leading chronic diseases: a comparative analysis of prevailing explanations.

PubMed

Stuckler, David

2008-06-01

The mortality numbers and rates of chronic disease are rising faster in developing than in developed countries. This article compares prevailing explanations of population chronic disease trends with theoretical and empirical models of population chronic disease epidemiology and assesses some economic consequences of the growth of chronic diseases in developing countries based on the experiences of developed countries. Four decades of male mortality rates of cardiovascular and chronic noncommunicable diseases were regressed on changes in and levels of country income per capita, market integration, foreign direct investment, urbanization rates, and population aging in fifty-six countries for which comparative data were available. Neoclassical economic growth models were used to estimate the effect of the mortality rates of chronic noncommunicable diseases on economic growth in high-income OECD countries. Processes of economic growth, market integration, foreign direct investment, and urbanization were significant determinants of long-term changes in mortality rates of heart disease and chronic noncommunicable disease, and the observed relationships with these social and economic factors were roughly three times stronger than the relationships with the population's aging. In low-income countries, higher levels of country income per capita, population urbanization, foreign direct investment, and market integration were associated with greater mortality rates of heart disease and chronic noncommunicable disease, less increased or sometimes reduced rates in middle-income countries, and decreased rates in high-income countries. Each 10 percent increase in the working-age mortality rates of chronic noncommunicable disease decreased economic growth rates by close to a half percent. Macrosocial and macroeconomic forces are major determinants of population rises in chronic disease mortality, and some prevailing demographic explanations, such as population aging, are incomplete on methodological, empirical, and policy grounds. Rising chronic disease mortality rates will significantly reduce economic growth in developing countries and further widen the health and economic gap between the developed and developing world.

SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion

NASA Astrophysics Data System (ADS)

Contreras, Carlos; Phillips, M. M.; Burns, Christopher R.; Piro, Anthony L.; Shappee, B. J.; Stritzinger, Maximilian D.; Baltay, C.; Brown, Peter J.; Conseil, Emmanuel; Klotz, Alain; Nugent, Peter E.; Turpin, Damien; Parker, Stu; Rabinowitz, D.; Hsiao, Eric Y.; Morrell, Nidia; Campillay, Abdo; Castellón, Sergio; Corco, Carlos; González, Consuelo; Krisciunas, Kevin; Serón, Jacqueline; Tucker, Brad E.; Walker, E. S.; Baron, E.; Cain, C.; Childress, Michael J.; Folatelli, Gastón; Freedman, Wendy L.; Hamuy, Mario; Hoeflich, P.; Persson, S. E.; Scalzo, Richard; Schmidt, Brian; Suntzeff, Nicholas B.

2018-05-01

We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from ‑12 to +140 days with respect to the epoch of B-band maximum ({t}{B\\max }). Supplementary imaging at the earliest epochs reveals an initial slow and nearly linear rise in luminosity with a duration of ∼2.5 days, followed by a faster rising phase that is well reproduced by an explosion model with a moderate amount of 56Ni mixing in the ejecta. From our analysis of the light curves, we conclude that: (i) the explosion occurred <22 hr before the first detection of the supernova, (ii) the rise time to peak bolometric (λ > 1800 Å) luminosity was 16.5 ± 0.6 days, (iii) the supernova suffered little or no host-galaxy dust reddening, (iv) the peak luminosity in both the optical and near-infrared was consistent with the bright end of normal Type Ia diversity, and (v) 0.60 ± 0.15 M ⊙ of 56Ni was synthesized in the explosion. Despite its normal luminosity, SN 2012fr displayed unusually prevalent high-velocity Ca II and Si II absorption features, and a nearly constant photospheric velocity of the Si II λ6355 line at ∼12,000 {km} {{{s}}}-1 that began ∼5 days before {t}{B\\max }. We also highlight some of the other peculiarities in the early phase photometry and the spectral evolution. SN 2012fr also adds to a growing number of Type Ia supernovae that are hosted by galaxies with direct Cepheid distance measurements. This paper includes data gathered with the 6.5 m Magellan Baade Telescope, located at Las Campanas Observatory, Chile.

Population Causes and Consequences of Leading Chronic Diseases: A Comparative Analysis of Prevailing Explanations

PubMed Central

Stuckler, David

2008-01-01

Context The mortality numbers and rates of chronic disease are rising faster in developing than in developed countries. This article compares prevailing explanations of population chronic disease trends with theoretical and empirical models of population chronic disease epidemiology and assesses some economic consequences of the growth of chronic diseases in developing countries based on the experiences of developed countries. Methods Four decades of male mortality rates of cardiovascular and chronic noncommunicable diseases were regressed on changes in and levels of country income per capita, market integration, foreign direct investment, urbanization rates, and population aging in fifty-six countries for which comparative data were available. Neoclassical economic growth models were used to estimate the effect of the mortality rates of chronic noncommunicable diseases on economic growth in high-income OECD countries. Findings Processes of economic growth, market integration, foreign direct investment, and urbanization were significant determinants of long-term changes in mortality rates of heart disease and chronic noncommunicable disease, and the observed relationships with these social and economic factors were roughly three times stronger than the relationships with the population's aging. In low-income countries, higher levels of country income per capita, population urbanization, foreign direct investment, and market integration were associated with greater mortality rates of heart disease and chronic noncommunicable disease, less increased or sometimes reduced rates in middle-income countries, and decreased rates in high-income countries. Each 10 percent increase in the working-age mortality rates of chronic noncommunicable disease decreased economic growth rates by close to a half percent. Conclusions Macrosocial and macroeconomic forces are major determinants of population rises in chronic disease mortality, and some prevailing demographic explanations, such as population aging, are incomplete on methodological, empirical, and policy grounds. Rising chronic disease mortality rates will significantly reduce economic growth in developing countries and further widen the health and economic gap between the developed and developing world. PMID:18522614

NASA Airborne Campaigns Focus on Climate Impacts in the Arctic

NASA Image and Video Library

2017-12-08

This red plane is a DHC-3 Otter, the plane flown in NASA's Operation IceBridge-Alaska surveys of mountain glaciers in Alaska. Credit: Chris Larsen, University of Alaska-Fairbanks Over the past few decades, average global temperatures have been on the rise, and this warming is happening two to three times faster in the Arctic. As the region’s summer comes to a close, NASA is hard at work studying how rising temperatures are affecting the Arctic. NASA researchers this summer and fall are carrying out three Alaska-based airborne research campaigns aimed at measuring greenhouse gas concentrations near Earth’s surface, monitoring Alaskan glaciers, and collecting data on Arctic sea ice and clouds. Observations from these NASA campaigns will give researchers a better understanding of how the Arctic is responding to rising temperatures. The Arctic Radiation – IceBridge Sea and Ice Experiment, or ARISE, is a new NASA airborne campaign to collect data on thinning sea ice and measure cloud and atmospheric properties in the Arctic. The campaign was designed to address questions about the relationship between retreating sea ice and the Arctic climate. Arctic sea ice reflects sunlight away from Earth, moderating warming in the region. Loss of sea ice means more heat from the sun is absorbed by the ocean surface, adding to Arctic warming. In addition, the larger amount of open water leads to more moisture in the air, which affects the formation of clouds that have their own effect on warming, either enhancing or reducing it. Read more: www.nasa.gov/earthrightnow NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

A New Direct Coupled Regional-scale Meteorology and Chemistry Model

NASA Astrophysics Data System (ADS)

Li, J.; Hsu, S.; Liu, T.; Chiang, C.; Chang, J.

2007-12-01

WRF/Chem was first developed in the US and generously made available to the international research community a short time ago. Starting from this, many groups have contributed new components and subroutines to this model. Based on WRF/Chem, a new online integrated model system named WRF/ChemT was established in Taiwan. It is significantly different from WRF/Chem in the following important aspects. For an online model, all chemical species emission must be direct coupled to WRF meteorology. All publicly available versions of WRF/Chem do not have this fundamental coupling. For these WRF/Chem models all emission data must first be preprocessed by SMOKE or other emission models driven by MM5 or WRF meteorologies in offline manner. WRF/ChemT has a self-consistent online emission process. We replaced the old emission driver with NCU driver, the plume rise of point sources and biogenic VOCs emission are calculated online. So that meteorology model, emission model and chemistry transport model are coupled directly in WRF/ChemT. Cloud impact on actinic flux should be consistent with WRF cloud-aerosol submodel used, not just moisture parameterization. Photolysis rates in WRF/ChemT are self consistent in every sub modules. New dry deposition routines were developed including addition of a vertical mixing scheme named the Asymmetrical Convective Model (ACM) which is used in CMAQ. The advantage of using ACM submodel had been demonstrated in earlier studies. Computational inefficiency has been a lingering problem for WRF/Chem. We have worked on this aspect of WRF/Chem development and by using a new chemical solver and also reorganizing the operator splitting computational algorithm we have made significant computational speed gain. WRF/chemT is about a factor of 4 faster in the chemistry solver and a factor of 2 faster in chemical species transport. When added together it is about a factor of 2 faster than WRF/Chem(version 2.1.2), i. e. gas-phase chemistry and meteorology are now equally fast. WRF/ChemT was evaluated and applied in regional air quality research in Taiwan. The comparison with WRF/Chem and selected current applications will be discussed in this report.

Climate Change: Integrating Science and Economics

NASA Astrophysics Data System (ADS)

Prinn, R. G.

2008-12-01

The world is facing an ever-growing conflict between environment and development. Climate change is a century-scale threat requiring a century-long effort in science, technology and policy analysis, and institutions that can sustain this effort over generations. To inform policy development and implementation there is urgent need for better integration of the diverse components of the problem. Motivated by this challenge, we have developed the Integrated Global System Model (IGSM) at MIT. It comprises coupled sub- models of economic development, atmospheric chemistry, climate dynamics and ecosystems. The results of a recent uncertainty analysis involving hundreds of runs of the IGSM imply that, without mitigation policies, the global average surface temperature may rise much faster than previously estimated. Polar temperatures are projected to rise even faster than the average rate with obvious great risks for high latitude ecosystems and ice sheets at the high end of this range. Analysis of policies for climate mitigation, show that the greatest effect of these policies is to lower the probability of extreme changes as opposed to lowering the medians. Faced with the above estimated impacts, the long lifetimes of most greenhouse gases in the atmosphere, the long delay in ultimate warming due to ocean heat uptake, and the capital-intensive global energy infrastructure, the case is strong for concerted action now. Results of runs of the IGSM indicate the need for transformation of the global energy industry on a very large scale to mitigate climate change. Carbon sequestration, renewable energy sources, and nuclear present new economic, technological, and environmental challenges when implemented at the needed scales. Economic analyses using the IGSM indicate that global implementation of efficient policies could allow the needed transformations at bearable costs.

An evaluation of rise time characterization and prediction methods

NASA Technical Reports Server (NTRS)

Robinson, Leick D.

1994-01-01

One common method of extrapolating sonic boom waveforms from aircraft to ground is to calculate the nonlinear distortion, and then add a rise time to each shock by a simple empirical rule. One common rule is the '3 over P' rule which calculates the rise time in milliseconds as three divided by the shock amplitude in psf. This rule was compared with the results of ZEPHYRUS, a comprehensive algorithm which calculates sonic boom propagation and extrapolation with the combined effects of nonlinearity, attenuation, dispersion, geometric spreading, and refraction in a stratified atmosphere. It is shown there that the simple empirical rule considerably overestimates the rise time estimate. In addition, the empirical rule does not account for variations in the rise time due to humidity variation or propagation history. It is also demonstrated that the rise time is only an approximate indicator of perceived loudness. Three waveforms with identical characteristics (shock placement, amplitude, and rise time), but with different shock shapes, are shown to give different calculated loudness. This paper is based in part on work performed at the Applied Research Laboratories, the University of Texas at Austin, and supported by NASA Langley.

An investigation of leg and trunk strength and reaction times of hard-style martial arts practitioners.

PubMed

Donovan, Oliver O; Cheung, Jeanette; Catley, Maria; McGregor, Alison H; Strutton, Paul H

2006-01-01

The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05). During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT)] but were significantly faster in moving to press another button [movement time (MT)]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts. Key PointsMartial artists undertaking hard-style martial arts have greater strength in their knee flexor and extensor muscles as tested under isokinetic testing. Under isometric testing conditions they have stronger knee extensors only.The trunk musculature is generally higher under both conditions of testing in the martial artists, although not significantly.The total reaction times of the martial artists to an auditory stimulus were significantly faster than the control participants. When analysed further it was revealed that the decrease in reaction time was due to the movement time component of the total reaction time.The training involved for the practice of the hard-style martial arts increases the strength of muscles involved in kicking. This increased strength is not seen in the trunk muscles. Furthermore, martial artists have a faster response time; the cause of which appears to be only the faster movement time.

An Investigation Of Leg And Trunk Strength And Reaction Times Of Hard-Style Martial Arts Practitioners

PubMed Central

Donovan, Oliver O; Cheung, Jeanette; Catley, Maria; McGregor, Alison H.; Strutton, Paul H.

2006-01-01

The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05). During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT)] but were significantly faster in moving to press another button [movement time (MT)]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts. Key Points Martial artists undertaking hard-style martial arts have greater strength in their knee flexor and extensor muscles as tested under isokinetic testing. Under isometric testing conditions they have stronger knee extensors only. The trunk musculature is generally higher under both conditions of testing in the martial artists, although not significantly. The total reaction times of the martial artists to an auditory stimulus were significantly faster than the control participants. When analysed further it was revealed that the decrease in reaction time was due to the movement time component of the total reaction time. The training involved for the practice of the hard-style martial arts increases the strength of muscles involved in kicking. This increased strength is not seen in the trunk muscles. Furthermore, martial artists have a faster response time; the cause of which appears to be only the faster movement time. PMID:24376366

Study on rapid bio-drying technology of cow dung with CaO2

NASA Astrophysics Data System (ADS)

Chen, Xiaotian; Qu, Guangfei; Liu, Shugen; Xie, Ruosong; He, Yanhua

2017-05-01

Effect of CaO2 on cow dung rapid bio-drying technology was researched. A static aerobic composting system was applied to this experiment which combining natural ventilation with Turing in the process of composting. The physical characteristics of cow dung was observed and the compost temperature, moisture content, organic matter, total nitrogen, total phosphorus, potassium content was determined which in order to study the effect of CaO2 on rapid drying of cattle in the compost. In the initial stage of compost, adding CaO2 groups compared with the control group, the temperature rise faster, 4-6 days in advance to the thermophilic phase; at the end of composting, the CaO2 composition and moisture content decreased significantly to below 30%. The addition of CaO2 in fertilizer was shorten the composting time, extend the thermophilic phase, to provide sufficient oxygen meeting the growth needs of aerobic microorganisms. It convinced that the rapid bio-drying of dairy manure has a good effect and provided a new idea for the effective treatment of cow dung.

Propagation and dispersion of shock waves in magnetoelastic materials

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

Crum, R. S.; Domann, J. P.; Carman, G. P.

Previous studies examining the response of magnetoelastic materials to shock waves have predominantly focused on applications involving pulsed power generation, with limited attention given to the actual wave propagation characteristics. This study provides detailed magnetic and mechanical measurements of magnetoelastic shock wave propagation and dispersion. Laser generated rarefacted shock waves exceeding 3 GPa with rise times of 10 ns were introduced to samples of the magnetoelastic material Galfenol. The resulting mechanical measurements reveal the evolution of the shock into a compressive acoustic front with lateral release waves. Importantly, the wave continues to disperse even after it has decayed into anmore » acoustic wave, due in large part to magnetoelastic coupling. The magnetic data reveal predominantly shear wave mediated magnetoelastic coupling, and were also used to noninvasively measure the wave speed. The external magnetic field controlled a 30% increase in wave propagation speed, attributed to a 70% increase in average stiffness. Lastly, magnetic signals propagating along the sample over 20× faster than the mechanical wave were measured, indicating these materials can act as passive antennas that transmit information in response to mechanical stimuli.« less

Propagation and dispersion of shock waves in magnetoelastic materials

NASA Astrophysics Data System (ADS)

Crum, R. S.; Domann, J. P.; Carman, G. P.; Gupta, V.

2017-12-01

Previous studies examining the response of magnetoelastic materials to shock waves have predominantly focused on applications involving pulsed power generation, with limited attention given to the actual wave propagation characteristics. This study provides detailed magnetic and mechanical measurements of magnetoelastic shock wave propagation and dispersion. Laser generated rarefacted shock waves exceeding 3 GPa with rise times of 10 ns were introduced to samples of the magnetoelastic material Galfenol. The resulting mechanical measurements reveal the evolution of the shock into a compressive acoustic front with lateral release waves. Importantly, the wave continues to disperse even after it has decayed into an acoustic wave, due in large part to magnetoelastic coupling. The magnetic data reveal predominantly shear wave mediated magnetoelastic coupling, and were also used to noninvasively measure the wave speed. The external magnetic field controlled a 30% increase in wave propagation speed, attributed to a 70% increase in average stiffness. Finally, magnetic signals propagating along the sample over 20× faster than the mechanical wave were measured, indicating these materials can act as passive antennas that transmit information in response to mechanical stimuli.

Role of Rayleigh numbers on characteristics of double diffusive salt fingers

NASA Astrophysics Data System (ADS)

Rehman, F.; Singh, O. P.

2018-05-01

Double diffusion convection, driven by two constituents of the fluid with different molecular diffusivity, is widely applied in oceanography and large number of other fields like astrophysics, geology, chemistry and metallurgy. In case of ocean, heat (T) and salinity (S) are the two components with varying diffusivity, where heat diffuses hundred times faster than salt. Component (T) stabilizes the system whereas components (S) destabilizes the system with overall density remains stable and forms the rising and sinking fingers known as salt fingers. Recent observations suggest that salt finger characteristics such as growth rates, wavenumber, and fluxes are strongly depending on the Rayleigh numbers as major driving force. In this paper, we corroborate this observation with the help of experiments, numerical simulations and linear theory. An eigenvalue expression for growth rate is derived from the linearized governing equations with explicit dependence on Rayleigh numbers, density stability ratio, Prandtl number and diffusivity ratio. Expressions for fastest growing fingers are also derived as a function various non-dimensional parameter. The predicted results corroborate well with the data reported from the field measurements, experiments and numerical simulations.

Increased core body temperature in astronauts during long-duration space missions.

PubMed

Stahn, Alexander C; Werner, Andreas; Opatz, Oliver; Maggioni, Martina A; Steinach, Mathias; von Ahlefeld, Victoria Weller; Moore, Alan; Crucian, Brian E; Smith, Scott M; Zwart, Sara R; Schlabs, Thomas; Mendt, Stefan; Trippel, Tobias; Koralewski, Eberhard; Koch, Jochim; Choukèr, Alexander; Reitz, Günther; Shang, Peng; Röcker, Lothar; Kirsch, Karl A; Gunga, Hanns-Christian

2017-11-23

Humans' core body temperature (CBT) is strictly controlled within a narrow range. Various studies dealt with the impact of physical activity, clothing, and environmental factors on CBT regulation under terrestrial conditions. However, the effects of weightlessness on human thermoregulation are not well understood. Specifically, studies, investigating the effects of long-duration spaceflight on CBT at rest and during exercise are clearly lacking. We here show that during exercise CBT rises higher and faster in space than on Earth. Moreover, we observed for the first time a sustained increased astronauts' CBT also under resting conditions. This increase of about 1 °C developed gradually over 2.5 months and was associated with augmented concentrations of interleukin-1 receptor antagonist, a key anti-inflammatory protein. Since even minor increases in CBT can impair physical and cognitive performance, both findings have a considerable impact on astronauts' health and well-being during future long-term spaceflights. Moreover, our findings also pinpoint crucial physiological challenges for spacefaring civilizations, and raise questions about the assumption of a thermoregulatory set point in humans, and our evolutionary ability to adapt to climate changes on Earth.

Object tracking with robotic total stations: Current technologies and improvements based on image data

NASA Astrophysics Data System (ADS)

Ehrhart, Matthias; Lienhart, Werner

2017-09-01

The importance of automated prism tracking is increasingly triggered by the rising automation of total station measurements in machine control, monitoring and one-person operation. In this article we summarize and explain the different techniques that are used to coarsely search a prism, to precisely aim at a prism, and to identify whether the correct prism is tracked. Along with the state-of-the-art review, we discuss and experimentally evaluate possible improvements based on the image data of an additional wide-angle camera which is available for many total stations today. In cases in which the total station's fine aiming module loses the prism, the tracked object may still be visible to the wide-angle camera because of its larger field of view. The theodolite angles towards the target can then be derived from its image coordinates which facilitates a fast reacquisition of the prism. In experimental measurements we demonstrate that our image-based approach for the coarse target search is 4 to 10-times faster than conventional approaches.

Analysis of ultraviolet photo-response of ZnO nanostructures prepared by electrodeposition and atomic layer deposition

NASA Astrophysics Data System (ADS)

Makhlouf, Houssin; Karam, Chantal; Lamouchi, Amina; Tingry, Sophie; Miele, Philippe; Habchi, Roland; Chtourou, Radhouane; Bechelany, Mikhael

2018-06-01

In this work, ZnO nanowires (ZnO NWs) and urchin-like ZnO nanowires (U-ZnO NWs) based on self-assembled ordered polystyrene sphere (PS) were successfully prepared by combining atomic layer deposition (ALD) and electrochemical deposition (ECD) processes to build UV photosensors. The photo-response of the prepared samples was investigated and compared. The growth of the nanowires on self-assembled, ordered PS introduces a significant modification on the morphology, crystal orientation and grain size of U-ZnO NWs compared to randomly, vertically aligned ZnO NWs, and therefore improves the photo-response of U-ZnO NWs. The photocurrent may be produced by either a surface or bulk-related process. For ZnO NW-based photosensors, the photocurrent was monitored by a surface related process, whereas, it was mainly governed by a bulk related process for U-ZnO NWs, resulting in a higher and faster photo-response. The study of the rise and decay time constants for both materials showed that these parameters were strikingly sensitive to the optical properties.

The economic costs and benefits of dental education: an empirical analysis.

PubMed

Stafford, Gary L; Nourzad, Farrokh; Lobb, William K; Beall, Jason R

2014-11-01

The rising costs associated with obtaining a dental education have caused some to question the financial benefit of pursuing a dental degree. There is a concern that recent graduates may have difficulty finding professional opportunities that provide the income necessary to service their accumulated educational debt. The aim of this study was to evaluate the trends in educational costs to aid in making an accurate appraisal of the financial benefit of a dental education. Adjusted into constant dollar terms, data from a variety of sources were collected for economic variables such as tuition, fees, student indebtedness, and dentists' earnings. These variables were then analyzed to determine the true costs and benefits of obtaining a dental education. The results showed that, over the course of the last decade, educational costs increased faster than the real net income of practicing dentists, which led to a decline in the return on investment in dental education. However, regardless of an applicant's choice of public or private dental school, there continues to be a positive economic return on students' commitment of both financial resources and time to receive a dental education.

A prominence eruption driven by flux feeding from chromospheric fibrils

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

Zhang, Quanhao; Liu, Rui; Wang, Yuming

2014-07-10

We present multi-wavelength observations of a prominence eruption originating from a quadrupolar field configuration, in which the prominence was embedded in a side arcade. Within the two-day period prior to its eruption on 2012 October 22, the prominence was perturbed three times by chromospheric fibrils underneath, which rose upward, became brightened, and merged into the prominence, resulting in horizontal flows along the prominence axis, suggesting that the fluxes carried by the fibrils were incorporated into the magnetic field of the prominence. These perturbations caused the prominence to oscillate and to rise faster than before. The absence of intense heating withinmore » the first two hours after the onset of the prominence eruption, which followed an exponential increase in height, indicates that ideal instability played a crucial role. The eruption involved interactions with the other side arcade, leading up to a twin coronal mass ejection, which was accompanied by transient surface brightenings in the central arcade, followed by transient dimmings and brightenings in the two side arcades. We suggest that flux feeding from chromospheric fibrils might be an important mechanism to trigger coronal eruptions.« less

Evidence for aversive withdrawal response to own errors.

PubMed

Hochman, Eldad Yitzhak; Milman, Valery; Tal, Liron

2017-10-01

Recent model suggests that error detection gives rise to defensive motivation prompting protective behavior. Models of active avoidance behavior predict it should grow larger with threat imminence and avoidance. We hypothesized that in a task requiring left or right key strikes, error detection would drive an avoidance reflex manifested by rapid withdrawal of an erring finger growing larger with threat imminence and avoidance. In experiment 1, three groups differing by error-related threat imminence and avoidance performed a flanker task requiring left or right force sensitive-key strikes. As predicted, errors were followed by rapid force release growing faster with threat imminence and opportunity to evade threat. In experiment 2, we established a link between error key release time (KRT) and the subjective sense of inner-threat. In a simultaneous, multiple regression analysis of three error-related compensatory mechanisms (error KRT, flanker effect, error correction RT), only error KRT was significantly associated with increased compulsive checking tendencies. We propose that error response withdrawal reflects an error-withdrawal reflex. Copyright © 2017 Elsevier B.V. All rights reserved.

The tempo of human childhood: a maternal foot on the accelerator, a paternal foot on the brake.

PubMed

Kotler, Jennifer; Haig, David

2018-03-01

Relative to the life history of other great apes, that of humans is characterized by early weaning and short interbirth intervals (IBIs). We propose that in modern humans, birth until adrenarche, or the rise in adrenal androgens, developmentally corresponds to the period from birth until weaning in great apes and ancestral hominins. According to this hypothesis, humans achieved short IBIs by subdividing ancestral infancy into a nurseling phase, during which offspring fed at the breast, and a weanling phase, during which offspring fed specially prepared foods. Imprinted genes influence the timing of human weaning and adrenarche, with paternally expressed genes promoting delays in childhood maturation and maternally expressed genes promoting accelerated maturation. These observations suggest that the tempo of human development has been shaped by consequences for the fitness of kin, with faster development increasing maternal fitness at a cost to child fitness. The effects of imprinted genes suggest that the duration of the juvenile period (adrenarche until puberty) has also been shaped by evolutionary conflicts within the family. © 2018 The Authors Evolutionary Anthropology Published by Wiley Periodicals, Inc.

The tempo of human childhood: a maternal foot on the accelerator, a paternal foot on the brake

PubMed Central

Haig, David

2018-01-01

Abstract Relative to the life history of other great apes, that of humans is characterized by early weaning and short interbirth intervals (IBIs). We propose that in modern humans, birth until adrenarche, or the rise in adrenal androgens, developmentally corresponds to the period from birth until weaning in great apes and ancestral hominins. According to this hypothesis, humans achieved short IBIs by subdividing ancestral infancy into a nurseling phase, during which offspring fed at the breast, and a weanling phase, during which offspring fed specially prepared foods. Imprinted genes influence the timing of human weaning and adrenarche, with paternally expressed genes promoting delays in childhood maturation and maternally expressed genes promoting accelerated maturation. These observations suggest that the tempo of human development has been shaped by consequences for the fitness of kin, with faster development increasing maternal fitness at a cost to child fitness. The effects of imprinted genes suggest that the duration of the juvenile period (adrenarche until puberty) has also been shaped by evolutionary conflicts within the family. PMID:29575348

Propagation and dispersion of shock waves in magnetoelastic materials

DOE PAGES

Crum, R. S.; Domann, J. P.; Carman, G. P.; ...

2017-11-15

Previous studies examining the response of magnetoelastic materials to shock waves have predominantly focused on applications involving pulsed power generation, with limited attention given to the actual wave propagation characteristics. This study provides detailed magnetic and mechanical measurements of magnetoelastic shock wave propagation and dispersion. Laser generated rarefacted shock waves exceeding 3 GPa with rise times of 10 ns were introduced to samples of the magnetoelastic material Galfenol. The resulting mechanical measurements reveal the evolution of the shock into a compressive acoustic front with lateral release waves. Importantly, the wave continues to disperse even after it has decayed into anmore » acoustic wave, due in large part to magnetoelastic coupling. The magnetic data reveal predominantly shear wave mediated magnetoelastic coupling, and were also used to noninvasively measure the wave speed. The external magnetic field controlled a 30% increase in wave propagation speed, attributed to a 70% increase in average stiffness. Lastly, magnetic signals propagating along the sample over 20× faster than the mechanical wave were measured, indicating these materials can act as passive antennas that transmit information in response to mechanical stimuli.« less

A Biogeotechnical engineering approach to Combat Desertification

NASA Astrophysics Data System (ADS)

Chang, I.; Im, J.; Cho, G. C.; Lee, S. J.

2016-12-01

The acceleration of global warming is not only inducing rising sea levels and abnormal climate problems, but also geotechnical hazards such as desertification. Recently, 30% of Earth's dry land has been affected by desertification, and approximately 850 million people are suffering due to famine, poverty, and hygiene problems induced by desertification. Global warming and unsustainable land development are known to be major triggers promoting desertification. Numerous global agencies and companies are thus contributing to anti-desertification movements. However, tree planting alone is not an ideal solution given that it takes approximately 2 3 years for stabilization. It is thus imperative to develop innovative technology that can promote vegetation growth and improve soil erosion resistance. In this study, a unique soil treatment and anti-desertification method is developed using microbial biopolymers. Biopolymers can effectively strengthen soil and improve durability. In particular, anionic-hydrophilic biopolymers delay water evaporation, thereby retaining a higher soil moisture condition compared to non-treated soil. Results of this study show that microbial biopolymer treatment is highly effective in improving both vegetation growth (3 times faster) and soil erosion resistance (less than 2%), compared to untreated earth surfaces.

Group living accelerates bed bug (Hemiptera: Cimicidae) development.

PubMed

Saenz, Virna L; Santangelo, Richard G; Vargo, Edward L; Schal, Coby

2014-01-01

For many insect species, group living provides physiological and behavioral benefits, including faster development. Bed bugs (Cimex lectularius L.) live in aggregations composed of eggs, nymphs, and adults of various ages. Our aim was to determine whether bed bug nymphs reared in groups develop faster than solitary nymphs. We reared first instars either in isolation or in groups from hatching to adult emergence and recorded their development time. In addition, we investigated the effects of group housing on same-age nymphs versus nymphs reared with adults. Nymphal development was 2.2 d faster in grouped nymphs than in solitary-housed nymphs, representing 7.3% faster overall development. However, this grouping effect did not appear to be influenced by group composition. Thus, similar to other gregarious insect species, nymph development in bed bugs is faster in aggregations than in isolation.

Implications on 1 + 1 D Tsunami Runup Modeling due to Time Features of the Earthquake Source

NASA Astrophysics Data System (ADS)

Fuentes, M.; Riquelme, S.; Ruiz, J.; Campos, J.

2018-02-01

The time characteristics of the seismic source are usually neglected in tsunami modeling, due to the difference in the time scale of both processes. Nonetheless, there are just a few analytical studies that intended to explain separately the role of the rise time and the rupture velocity. In this work, we extend an analytical 1 + 1 D solution for the shoreline motion time series, from the static case to the kinematic case, by including both rise time and rupture velocity. Our results show that the static case corresponds to a limit case of null rise time and infinite rupture velocity. Both parameters contribute in shifting the arrival time, but maximum runup may be affected by very slow ruptures and long rise time. Parametric analysis reveals that runup is strictly decreasing with the rise time while is highly amplified in a certain range of slow rupture velocities. For even lower rupture velocities, the tsunami excitation vanishes and for larger, quicker approaches to the instantaneous case.

Implications on 1 + 1 D Tsunami Runup Modeling due to Time Features of the Earthquake Source

NASA Astrophysics Data System (ADS)

Fuentes, M.; Riquelme, S.; Ruiz, J.; Campos, J.

2018-04-01

The time characteristics of the seismic source are usually neglected in tsunami modeling, due to the difference in the time scale of both processes. Nonetheless, there are just a few analytical studies that intended to explain separately the role of the rise time and the rupture velocity. In this work, we extend an analytical 1 + 1 D solution for the shoreline motion time series, from the static case to the kinematic case, by including both rise time and rupture velocity. Our results show that the static case corresponds to a limit case of null rise time and infinite rupture velocity. Both parameters contribute in shifting the arrival time, but maximum runup may be affected by very slow ruptures and long rise time. Parametric analysis reveals that runup is strictly decreasing with the rise time while is highly amplified in a certain range of slow rupture velocities. For even lower rupture velocities, the tsunami excitation vanishes and for larger, quicker approaches to the instantaneous case.

Faster Trees: Strategies for Accelerated Training and Prediction of Random Forests for Classification of Polsar Images

NASA Astrophysics Data System (ADS)

Hänsch, Ronny; Hellwich, Olaf

2018-04-01

Random Forests have continuously proven to be one of the most accurate, robust, as well as efficient methods for the supervised classification of images in general and polarimetric synthetic aperture radar data in particular. While the majority of previous work focus on improving classification accuracy, we aim for accelerating the training of the classifier as well as its usage during prediction while maintaining its accuracy. Unlike other approaches we mainly consider algorithmic changes to stay as much as possible independent of platform and programming language. The final model achieves an approximately 60 times faster training and a 500 times faster prediction, while the accuracy is only marginally decreased by roughly 1 %.

Multiple object tracking using the shortest path faster association algorithm.

PubMed

Xi, Zhenghao; Liu, Heping; Liu, Huaping; Yang, Bin

2014-01-01

To solve the persistently multiple object tracking in cluttered environments, this paper presents a novel tracking association approach based on the shortest path faster algorithm. First, the multiple object tracking is formulated as an integer programming problem of the flow network. Then we relax the integer programming to a standard linear programming problem. Therefore, the global optimum can be quickly obtained using the shortest path faster algorithm. The proposed method avoids the difficulties of integer programming, and it has a lower worst-case complexity than competing methods but better robustness and tracking accuracy in complex environments. Simulation results show that the proposed algorithm takes less time than other state-of-the-art methods and can operate in real time.

Multiple Object Tracking Using the Shortest Path Faster Association Algorithm

PubMed Central

Liu, Heping; Liu, Huaping; Yang, Bin

2014-01-01

To solve the persistently multiple object tracking in cluttered environments, this paper presents a novel tracking association approach based on the shortest path faster algorithm. First, the multiple object tracking is formulated as an integer programming problem of the flow network. Then we relax the integer programming to a standard linear programming problem. Therefore, the global optimum can be quickly obtained using the shortest path faster algorithm. The proposed method avoids the difficulties of integer programming, and it has a lower worst-case complexity than competing methods but better robustness and tracking accuracy in complex environments. Simulation results show that the proposed algorithm takes less time than other state-of-the-art methods and can operate in real time. PMID:25215322

Choosing the Most Effective Pattern Classification Model under Learning-Time Constraint.

PubMed

Saito, Priscila T M; Nakamura, Rodrigo Y M; Amorim, Willian P; Papa, João P; de Rezende, Pedro J; Falcão, Alexandre X

2015-01-01

Nowadays, large datasets are common and demand faster and more effective pattern analysis techniques. However, methodologies to compare classifiers usually do not take into account the learning-time constraints required by applications. This work presents a methodology to compare classifiers with respect to their ability to learn from classification errors on a large learning set, within a given time limit. Faster techniques may acquire more training samples, but only when they are more effective will they achieve higher performance on unseen testing sets. We demonstrate this result using several techniques, multiple datasets, and typical learning-time limits required by applications.

Amplitude- and rise-time-compensated filters

DOEpatents

Nowlin, Charles H.

1984-01-01

An amplitude-compensated rise-time-compensated filter for a pulse time-of-occurrence (TOOC) measurement system is disclosed. The filter converts an input pulse, having the characteristics of random amplitudes and random, non-zero rise times, to a bipolar output pulse wherein the output pulse has a zero-crossing time that is independent of the rise time and amplitude of the input pulse. The filter differentiates the input pulse, along the linear leading edge of the input pulse, and subtracts therefrom a pulse fractionally proportional to the input pulse. The filter of the present invention can use discrete circuit components and avoids the use of delay lines.

Finite element computation on nearest neighbor connected machines

NASA Technical Reports Server (NTRS)

Mcaulay, A. D.

1984-01-01

Research aimed at faster, more cost effective parallel machines and algorithms for improving designer productivity with finite element computations is discussed. A set of 8 boards, containing 4 nearest neighbor connected arrays of commercially available floating point chips and substantial memory, are inserted into a commercially available machine. One-tenth Mflop (64 bit operation) processors provide an 89% efficiency when solving the equations arising in a finite element problem for a single variable regular grid of size 40 by 40 by 40. This is approximately 15 to 20 times faster than a much more expensive machine such as a VAX 11/780 used in double precision. The efficiency falls off as faster or more processors are envisaged because communication times become dominant. A novel successive overrelaxation algorithm which uses cyclic reduction in order to permit data transfer and computation to overlap in time is proposed.

Faster than Real-Time Dynamic Simulation for Large-Size Power System with Detailed Dynamic Models using High-Performance Computing Platform

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

Huang, Renke; Jin, Shuangshuang; Chen, Yousu

This paper presents a faster-than-real-time dynamic simulation software package that is designed for large-size power system dynamic simulation. It was developed on the GridPACKTM high-performance computing (HPC) framework. The key features of the developed software package include (1) faster-than-real-time dynamic simulation for a WECC system (17,000 buses) with different types of detailed generator, controller, and relay dynamic models, (2) a decoupled parallel dynamic simulation algorithm with optimized computation architecture to better leverage HPC resources and technologies, (3) options for HPC-based linear and iterative solvers, (4) hidden HPC details, such as data communication and distribution, to enable development centered on mathematicalmore » models and algorithms rather than on computational details for power system researchers, and (5) easy integration of new dynamic models and related algorithms into the software package.« less

Features of Modularly Assembled Compounds That Impart Bioactivity Against an RNA Target

PubMed Central

Rzuczek, Suzanne G.; Gao, Yu; Tang, Zhen-Zhi; Thornton, Charles A.; Kodadek, Thomas; Disney, Matthew D.

2013-01-01

Transcriptomes provide a myriad of potential RNAs that could be the targets of therapeutics or chemical genetic probes of function. Cell permeable small molecules, however, generally do not exploit these targets, owing to the difficulty in the design of high affinity, specific small molecules targeting RNA. As part of a general program to study RNA function using small molecules, we designed bioactive, modularly assembled small molecules that target the non-coding expanded RNA repeat that causes myotonic dystrophy type 1 (DM1), r(CUG)exp. Herein, we present a rigorous study to elucidate features in modularly assembled compounds that afford bioactivity. Different modular assembly scaffolds were investigated including polyamines, α-peptides, β-peptides, and peptide tertiary amides (PTAs). Based on activity as assessed by improvement of DM1-associated defects, stability against proteases, cellular permeability, and toxicity, we discovered that constrained backbones, namely PTAs, are optimal. Notably, we determined that r(CUG)exp is the target of the optimal PTA in cellular models and that the optimal PTA improves DM1-associated defects in a mouse model. Biophysical analyses were employed to investigate potential sources of bioactivity. These investigations show that modularly assembled compounds have increased residence times on their targets and faster on rates than the RNA-binding modules from which they were derived and faster on rates than the protein that binds r(CUG)exp, the inactivation of which gives rise to DM1-associated defects. These studies provide information about features of small molecules that are programmable for targeting RNA, allowing for the facile optimization of therapeutics or chemical probes against other cellular RNA targets. PMID:24032410

Features of modularly assembled compounds that impart bioactivity against an RNA target.

PubMed

Rzuczek, Suzanne G; Gao, Yu; Tang, Zhen-Zhi; Thornton, Charles A; Kodadek, Thomas; Disney, Matthew D

2013-10-18

Transcriptomes provide a myriad of potential RNAs that could be the targets of therapeutics or chemical genetic probes of function. Cell-permeable small molecules, however, generally do not exploit these targets, owing to the difficulty in the design of high affinity, specific small molecules targeting RNA. As part of a general program to study RNA function using small molecules, we designed bioactive, modularly assembled small molecules that target the noncoding expanded RNA repeat that causes myotonic dystrophy type 1 (DM1), r(CUG)(exp). Herein, we present a rigorous study to elucidate features in modularly assembled compounds that afford bioactivity. Different modular assembly scaffolds were investigated, including polyamines, α-peptides, β-peptides, and peptide tertiary amides (PTAs). On the basis of activity as assessed by improvement of DM1-associated defects, stability against proteases, cellular permeability, and toxicity, we discovered that constrained backbones, namely, PTAs, are optimal. Notably, we determined that r(CUG)(exp) is the target of the optimal PTA in cellular models and that the optimal PTA improves DM1-associated defects in a mouse model. Biophysical analyses were employed to investigate potential sources of bioactivity. These investigations show that modularly assembled compounds have increased residence times on their targets and faster on rates than the RNA-binding modules from which they were derived. Moreover, they have faster on rates than the protein that binds r(CUG)(exp), the inactivation of which gives rise to DM1-associated defects. These studies provide information about features of small molecules that are programmable for targeting RNA, allowing for the facile optimization of therapeutics or chemical probes against other cellular RNA targets.

Insulin Delivery Into the Peripheral Circulation: A Key Contributor to Hypoglycemia in Type 1 Diabetes

PubMed Central

Kraft, Guillaume; Scott, Melanie F.; Neal, Doss W.; Farmer, Ben; Smith, Marta S.; Hastings, Jon R.; Allen, Eric J.; Donahue, E. Patrick; Rivera, Noelia; Winnick, Jason J.; Edgerton, Dale S.; Nishimura, Erica; Fledelius, Christian; Brand, Christian L.; Cherrington, Alan D.

2015-01-01

Hypoglycemia limits optimal glycemic control in type 1 diabetes mellitus (T1DM), making novel strategies to mitigate it desirable. We hypothesized that portal (Po) vein insulin delivery would lessen hypoglycemia. In the conscious dog, insulin was infused into the hepatic Po vein or a peripheral (Pe) vein at a rate four times of basal. In protocol 1, a full counterregulatory response was allowed, whereas in protocol 2, glucagon was fixed at basal, mimicking the diminished α-cell response to hypoglycemia seen in T1DM. In protocol 1, glucose fell faster with Pe insulin than with Po insulin, reaching 56 ± 3 vs. 70 ± 6 mg/dL (P = 0.04) at 60 min. The change in area under the curve (ΔAUC) for glucagon was similar between Pe and Po, but the peak occurred earlier in Pe. The ΔAUC for epinephrine was greater with Pe than with Po (67 ± 17 vs. 36 ± 14 ng/mL/180 min). In protocol 2, glucose also fell more rapidly than in protocol 1 and fell faster in Pe than in Po, reaching 41 ± 3 vs. 67 ± 2 mg/dL (P < 0.01) by 60 min. Without a rise in glucagon, the epinephrine responses were much larger (ΔAUC of 204 ± 22 for Pe vs. 96 ± 29 ng/mL/180 min for Po). In summary, Pe insulin delivery exacerbates hypoglycemia, particularly in the presence of a diminished glucagon response. Po vein insulin delivery, or strategies that mimic it (i.e., liver-preferential insulin analogs), should therefore lessen hypoglycemia. PMID:26085570

The Rise and Fall of Type Ia Supernova Light Curves in the SDSS-II Supernova Survey

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

Hayden, Brian T.; /Notre Dame U.; Garnavich, Peter M.

2010-01-01

We analyze the rise and fall times of Type Ia supernova (SN Ia) light curves discovered by the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. From a set of 391 light curves k-corrected to the rest-frame B and V bands, we find a smaller dispersion in the rising portion of the light curve compared to the decline. This is in qualitative agreement with computer models which predict that variations in radioactive nickel yield have less impact on the rise than on the spread of the decline rates. The differences we find in the rise and fall properties suggest that amore » single 'stretch' correction to the light curve phase does not properly model the range of SN Ia light curve shapes. We select a subset of 105 light curves well observed in both rise and fall portions of the light curves and develop a '2-stretch' fit algorithm which estimates the rise and fall times independently. We find the average time from explosion to B-band peak brightness is 17.38 {+-} 0.17 days, but with a spread of rise times which range from 13 days to 23 days. Our average rise time is shorter than the 19.5 days found in previous studies; this reflects both the different light curve template used and the application of the 2-stretch algorithm. The SDSS-II supernova set and the local SNe Ia with well-observed early light curves show no significant differences in their average rise-time properties. We find that slow-declining events tend to have fast rise times, but that the distribution of rise minus fall time is broad and single peaked. This distribution is in contrast to the bimodality in this parameter that was first suggested by Strovink (2007) from an analysis of a small set of local SNe Ia. We divide the SDSS-II sample in half based on the rise minus fall value, t{sub r} - t{sub f} {approx}< 2 days and t{sub r} - t{sub f} > 2 days, to search for differences in their host galaxy properties and Hubble residuals; we find no difference in host galaxy properties or Hubble residuals in our sample.« less

Ultrafast traveling wave dominates the electric organ discharge of Apteronotus leptorhynchus: an inverse modelling study.

PubMed

Shifman, Aaron R; Longtin, André; Lewis, John E

2015-10-30

Identifying and understanding the current sources that give rise to bioelectric fields is a fundamental problem in the biological sciences. It is very difficult, for example, to attribute the time-varying features of an electroencephalogram recorded from the head surface to the neural activity of specific brain areas; model systems can provide important insight into such problems. Some species of fish actively generate an oscillating (c. 1000 Hz) quasi-dipole electric field to communicate and sense their environment in the dark. A specialized electric organ comprises neuron-like cells whose collective signal underlies this electric field. As a step towards understanding the detailed biophysics of signal generation in these fish, we use an anatomically-detailed finite-element modelling approach to reverse-engineer the electric organ signal over one oscillation cycle. We find that the spatiotemporal profile of current along the electric organ constitutes a travelling wave that is well-described by two spatial Fourier components varying in time. The conduction velocity of this wave is faster than action potential conduction in any known neuronal axon (>200 m/s), suggesting that the spatiotemporal features of high-frequency electric organ discharges are not constrained by the conduction velocities of spinal neuron pathways.

Accelerated diversification is related to life history and locomotion in a hyperdiverse lineage of microbial eukaryotes (Diatoms, Bacillariophyta).

PubMed

Nakov, Teofil; Beaulieu, Jeremy M; Alverson, Andrew J

2018-04-06

Patterns of species richness are commonly linked to life history strategies. In diatoms, an exceptionally diverse lineage of photosynthetic heterokonts important for global photosynthesis and burial of atmospheric carbon, lineages with different locomotory and reproductive traits differ dramatically in species richness, but any potential association between life history strategy and diversification has not been tested in a phylogenetic framework. We constructed a time-calibrated, 11-gene, 1151-taxon phylogeny of diatoms - the most inclusive diatom species tree to date. We used this phylogeny, together with a comprehensive inventory of first-last occurrences of Cenozoic fossil diatoms, to estimate ranges of expected species richness, diversification and its variation through time and across lineages. Diversification rates varied with life history traits. Although anisogamous lineages diversified faster than oogamous ones, this increase was restricted to a nested clade with active motility in the vegetative cells. We propose that the evolution of motility in vegetative cells, following an earlier transition from oogamy to anisogamy, facilitated outcrossing and improved utilization of habitat complexity, ultimately leading to enhanced opportunity for adaptive divergence across a variety of novel habitats. Together, these contributed to a species radiation that gave rise to the majority of present-day diatom diversity. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

The temporal advantage for individuating objects of expertise: perceptual expertise is an early riser.

PubMed

Curby, Kim M; Gauthier, Isabel

2009-06-10

The identification of faces has a temporal advantage over that of other object categories. The orientation-specific nature of this advantage suggests that it stems from our extensive experience and resulting expertise with upright faces. While experts can identify objects faster than novices, it is unclear exactly how the temporal dynamics of identification are changed by expertise and whether the nature of this temporal advantage is similar for face and non-face objects of expertise. Here, we titrated encoding time using a backward-masking paradigm with variable stimulus-mask onset-asynchronies and mapped the resulting effect on recognition for upright and inverted faces (Experiment 1) and for cars among car experts and car novices (Experiment 2). Performance for upright faces and cars among car experts rose above chance between 33 and 70 ms before that for inverted faces or cars among car novices. A shifted exponential function fitted to these data suggested that performance started to rise earlier for experts than for novices, but that additional encoding time increased performance at a similar rate. Experience influences the availability of information early in processing, possibly through the recruitment of more category-selective neurons, while the rate of perceptual processing may be less flexible and limited by inherent physiological constraints.

Global Human Appropriation of Net Primary Production and Associated Resource Decoupling: 2010-2050.

PubMed

Zhou, Chuanbin; Elshkaki, Ayman; Graedel, T E

2018-02-06

Human appropriation of net primary production (HANPP) methodology has previously been developed to assess the intensity of anthropogenic extraction of biomass resources. However, there is limited analysis concerning future trends of HANPP. Here we present four scenarios for global biomass demand and HANPP harv (the most key component of HANPP) from 2010 to 2050 by incorporating data on expanded historical drivers and disaggregated biomass demand (food, wood material, and fuelwood). The results show that the biomass demand has the lowest value in the equitability world scenario (an egalitarian vision) and the highest value in the security foremost scenario (an isolationist vision). The biomass demand for food and materials increases over time, while fuelwood demand decreases over time. Global HANPP harv rises to between 8.5 and 10.1 Pg C/yr in 2050 in the four scenarios, 14-35% above its value in 2010, and some 50% of HANPP harv is calculated to be crop residues, wood residues, and food losses in the future. HANPP harv in developing regions (Asia, Africa, and Latin America) increases faster than that in more-developed regions (North America and Europe), due to urbanization, population growth, and increasing income. Decoupling of HANPP harv and socioeconomic development is also discussed in this work.

Ultrafast traveling wave dominates the electric organ discharge of Apteronotus leptorhynchus: an inverse modelling study

PubMed Central

Shifman, Aaron R.; Longtin, André; Lewis, John E.

2015-01-01

Identifying and understanding the current sources that give rise to bioelectric fields is a fundamental problem in the biological sciences. It is very difficult, for example, to attribute the time-varying features of an electroencephalogram recorded from the head surface to the neural activity of specific brain areas; model systems can provide important insight into such problems. Some species of fish actively generate an oscillating (c. 1000 Hz) quasi-dipole electric field to communicate and sense their environment in the dark. A specialized electric organ comprises neuron-like cells whose collective signal underlies this electric field. As a step towards understanding the detailed biophysics of signal generation in these fish, we use an anatomically-detailed finite-element modelling approach to reverse-engineer the electric organ signal over one oscillation cycle. We find that the spatiotemporal profile of current along the electric organ constitutes a travelling wave that is well-described by two spatial Fourier components varying in time. The conduction velocity of this wave is faster than action potential conduction in any known neuronal axon (>200 m/s), suggesting that the spatiotemporal features of high-frequency electric organ discharges are not constrained by the conduction velocities of spinal neuron pathways. PMID:26514932

Preparation of TPP-crosslinked chitosan microparticles by spray drying for the controlled delivery of progesterone intended for estrus synchronization in cattle.

PubMed

Helbling, Ignacio M; Busatto, Carlos A; Fioramonti, Silvana A; Pesoa, Juan I; Santiago, Liliana; Estenoz, Diana A; Luna, Julio A

2018-02-20

Planned reproduction in cattle involves regulation of estrous cycle and the use of artificial insemination. Cycle control includes the administration of exogenous progesterone during 5-8 days in a controlled manner allowing females to synchronize their ovulation. Several progesterone delivery systems are commercially available but they have several drawbacks. The aim of the present contribution was to evaluate chitosan microparticles entrapping progesterone as an alternative system. Microparticles were prepared by spray drying. The effect of formulation parameters and experimental conditions on particle features and delivery was studied. A mathematical model to predict progesterone plasma concentration in animals was developed and validated with experimental data. Microparticle size was not affected by formulation parameters but sphericity enhances as Tween 80 content increases and it impairs as TPP content rises. Z potential decreases as phosphate content rises. Particles remain stable in acidic solution but the addition of surfactant is required to stabilize dispersions in neutral medium. Encapsulation efficiencies was 69-75%. In vitro delivery studies showed burst and diffusion-controlled phases, being progesterone released faster at low pH. In addition, delivery extend in cows was affected mainly by particle size and hormone initial content, while the amount injected altered plasma concentration. Theoretical predictions with excellent accuracy were obtained. The mathematical model developed can help to find proper particle features to reach specific delivery rates in the animals. This not only save time, money and effort but also minimized experimentation with animals which is desired from an ethical point of view.

A survey of solar wind conditions at 5 AU: A tool for interpreting solar wind-magnetosphere interactions at Jupiter

NASA Astrophysics Data System (ADS)

Ebert, Robert; Bagenal, Fran; McComas, David; Fowler, Christopher

2014-09-01

We examine Ulysses solar wind and interplanetary magnetic field (IMF) observations at 5 AU for two ~13 month intervals during the rising and declining phases of solar cycle 23 and the predicted response of the Jovian magnetosphere during these times. The declining phase solar wind, composed primarily of corotating interaction regions and high-speed streams, was, on average, faster, hotter, less dense, and more Alfvénic relative to the rising phase solar wind, composed mainly of slow wind and interplanetary coronal mass ejections. Interestingly, none of solar wind and IMF distributions reported here were bimodal, a feature used to explain the bimodal distribution of bow shock and magnetopause standoff distances observed at Jupiter. Instead, many of these distributions had extended, non-Gaussian tails that resulted in large standard deviations and much larger mean over median values. The distribution of predicted Jupiter bow shock and magnetopause standoff distances during these intervals were also not bimodal, the mean/median values being larger during the declining phase by ~1 - 4%. These results provide data-derived solar wind and IMF boundary conditions at 5 AU for models aimed at studying solar wind-magnetosphere interactions at Jupiter and can support the science investigations of upcoming Jupiter system missions. Here, we provide expectations for Juno, which is scheduled to arrive at Jupiter in July 2016. Accounting for the long-term decline in solar wind dynamic pressure reported by McComas et al. (2013), Jupiter’s bow shock and magnetopause is expected to be at least 8 - 12% further from Jupiter, if these trends continue.

Safety Performance of Exterior Wall Insulation Material Based on Large Security Concept

NASA Astrophysics Data System (ADS)

Zuo, Q. L.; Wang, Y. J.; Li, J. S.

2018-05-01

In order to evaluate the fire spread characteristics of building insulation materials under corner fire, an experiment is carried out with small-scale fire spread test system. The change rule of the parameters such as the average height of the flame, the average temperature of the flame and the shape of the flame are analyzed. The variations of the fire spread characteristic parameters of the building insulation materials are investigated. The results show that the average temperature of Expanded Polystyrene (EPS) board, with different thickness, decrease - rise - decrease - increase. During the combustion process, the fire of 4cm thick plate spreads faster.

Influence of the dark exciton state on the optical and quantum optical properties of single quantum dots.

PubMed

Reischle, M; Beirne, G J; Rossbach, R; Jetter, M; Michler, P

2008-10-03

The dark exciton state strongly affects the optical and quantum optical properties of flat InP/GaInP quantum dots. The exciton intensity drops sharply compared to the biexciton with rising pulsed laser excitation power while the opposite is true with temperature. Also, the decay rate is faster for the exciton than the biexciton and the dark-to-bright state spin flip is enhanced with temperature. Furthermore, long-lived dark state related memory effects are observed in second-order cross-correlation measurements between the exciton and biexciton and have been simulated using a rate-equation model.

Variations in Carboxyhaemoglobin Levels in Smokers

PubMed Central

Castleden, C. M.; Cole, P. V.

1974-01-01

Three experiments on smokers have been performed to determine variations in blood levels of carboxyhaemoglobin (COHb) throughout the day and night and whether a random measurement of COHb gives a true estimation of a smoker's mean COHb level. In the individual smoker the COHb level does not increase gradually during the day but is kept within relatively narrow limits. Moderately heavy smokers rise in the morning with a substantially raised COHb level because the half life of COHb is significantly longer during sleep than during the day. Women excrete their carbon monoxide faster than men. A random COHb estimation gives a good indication of the mean COHb level of an individual. PMID:4441877

The Pace of Cultural Evolution

PubMed Central

Perreault, Charles

2012-01-01

Today, humans inhabit most of the world’s terrestrial habitats. This observation has been explained by the fact that we possess a secondary inheritance mechanism, culture, in addition to a genetic system. Because it is assumed that cultural evolution occurs faster than biological evolution, humans can adapt to new ecosystems more rapidly than other animals. This assumption, however, has never been tested empirically. Here, I compare rates of change in human technologies to rates of change in animal morphologies. I find that rates of cultural evolution are inversely correlated with the time interval over which they are measured, which is similar to what is known for biological rates. This correlation explains why the pace of cultural evolution appears faster when measured over recent time periods, where time intervals are often shorter. Controlling for the correlation between rates and time intervals, I show that (1) cultural evolution is faster than biological evolution; (2) this effect holds true even when the generation time of species is controlled for; and (3) culture allows us to evolve over short time scales, which are normally accessible only to short-lived species, while at the same time allowing for us to enjoy the benefits of having a long life history. PMID:23024804

Stimulus onset predictability modulates proactive action control in a Go/No-go task

PubMed Central

Berchicci, Marika; Lucci, Giuliana; Spinelli, Donatella; Di Russo, Francesco

2015-01-01

The aim of the study was to evaluate whether the presence/absence of visual cues specifying the onset of an upcoming, action-related stimulus modulates pre-stimulus brain activity, associated with the proactive control of goal-directed actions. To this aim we asked 12 subjects to perform an equal probability Go/No-go task with four stimulus configurations in two conditions: (1) uncued, i.e., without any external information about the timing of stimulus onset; and (2) cued, i.e., with external visual cues providing precise information about the timing of stimulus onset. During task both behavioral performance and event-related potentials (ERPs) were recorded. Behavioral results showed faster response times in the cued than uncued condition, confirming existing literature. ERPs showed novel results in the proactive control stage, that started about 1 s before the motor response. We observed a slow rising prefrontal positive activity, more pronounced in the cued than the uncued condition. Further, also pre-stimulus activity of premotor areas was larger in cued than uncued condition. In the post-stimulus period, the P3 amplitude was enhanced when the time of stimulus onset was externally driven, confirming that external cueing enhances processing of stimulus evaluation and response monitoring. Our results suggest that different pre-stimulus processing come into play in the two conditions. We hypothesize that the large prefrontal and premotor activities recorded with external visual cues index the monitoring of the external stimuli in order to finely regulate the action. PMID:25964751

Single-domain angiotensin I converting enzyme (kininase II): characterization and properties.

PubMed

Deddish, P A; Wang, L X; Jackman, H L; Michel, B; Wang, J; Skidgel, R A; Erdös, E G

1996-12-01

Somatic angiotensin I converting enzyme (ACE; kininase II) has two active sites, in two (N and C) domains. We studied the active centers with separate N-domain ACE (N-ACE), testicular C-domain ACE (germinal ACE) and, as control, renal somatic ACE. Germinal ACE cleaved the nonapeptide bradykinin about two times faster than N-ACE in 20 mM Cl-. Bradykinin1-7 was hydrolyzed further to bradykinin1-5 by N-ACE four times faster in the absence of Cl-, but at 300 mM Cl- the C-domain hydrolyzed it twice as fast. The hematopoietic system regulatory peptide acetyl-Ser-Asp-Lys-Pro was split to two dipeptides by N-ACE, depending on the chloride concentration, 8 to 24 times faster than by germinal ACE; at 100 mM Cl-, the Kcat with N-ACE was eight times higher. One millimolar 1-fluoro-2,4-dinitrobenzene inhibited germinal ACE 96% but it inhibited N-ACE by only 31%. [3H]Ramiprilat was displaced by other unlabeled ACE inhibitors to establish their relative affinities. Captopril had the lowest IC50 (0.5 nM) with N-ACE and the highest IC50 (8.3 nM) with the germinal ACE. The IC50 values of ramiprilat and quinaprilat were about the same with both active sites. The association and dissociation constants of [3H]ramiprilat indicated faster association with and faster dissociation from N-ACE than from germinal ACE. After exposure to alkali or moderate heat, somatic ACE was cleaved by plasmin and kallikrein, releasing N-ACE and apparently inactivating the C-domain. These studies affirm the differences in the activity, stability and inhibition of the two active sites of ACE.

GPU accelerated real-time confocal fluorescence lifetime imaging microscopy (FLIM) based on the analog mean-delay (AMD) method

PubMed Central

Kim, Byungyeon; Park, Byungjun; Lee, Seungrag; Won, Youngjae

2016-01-01

We demonstrated GPU accelerated real-time confocal fluorescence lifetime imaging microscopy (FLIM) based on the analog mean-delay (AMD) method. Our algorithm was verified for various fluorescence lifetimes and photon numbers. The GPU processing time was faster than the physical scanning time for images up to 800 × 800, and more than 149 times faster than a single core CPU. The frame rate of our system was demonstrated to be 13 fps for a 200 × 200 pixel image when observing maize vascular tissue. This system can be utilized for observing dynamic biological reactions, medical diagnosis, and real-time industrial inspection. PMID:28018724

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

Wu, Ping; Deng, Yuqun; Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024

In relativistic backward wave oscillators (RBWOs), although the slow wave structure (SWS) and electron beam determine the main characteristics of beam-wave interaction, many other factors can also significantly affect the microwave generation process. This paper investigates the influence of voltage rise time on beam-wave interaction in RBWOs. Preliminary analysis and PIC simulations demonstrate if the voltage rise time is moderately long, the microwave frequency will gradually increase during the startup process until the voltage reaches its amplitude, which can be explained by the dispersion relation. However, if the voltage rise time is long enough, the longitudinal resonance of the finitely-longmore » SWS will force the RBWO to work with unwanted longitudinal modes for a while and then gradually hop to the wanted longitudinal mode, and this will lead to an impure microwave frequency spectrum. Besides, a longer voltage rise time will delay the startup process and thus lead to a longer microwave saturation time. And if unwanted longitudinal modes are excited due to long voltage rise time, the microwave saturation time will be further lengthened. Therefore, the voltage rise time of accelerators adopted in high power microwave technology should not be too long in case unwanted longitudinal modes are excited.« less

Mechanical Determinants of Faster Change of Direction Speed Performance in Male Athletes.

PubMed

DosʼSantos, Thomas; Thomas, Christopher; Jones, Paul A; Comfort, Paul

2017-03-01

Dos'Santos, T, Thomas, C, Jones, PA, and Comfort, P. Mechanical determinants of faster change of direction speed performance in male athletes. J Strength Cond Res 31(3): 696-705, 2017-Mechanical variables during change of directions, for example, braking and propulsive forces, impulses, and ground contact times (GCT) have been identified as determinants of faster change of direction speed (CODS) performance. The purpose of this study was to investigate the mechanical determinants of 180° CODS performance with mechanical characteristic comparisons between faster and slower performers; while exploring the role of the penultimate foot contact (PEN) during the change of direction. Forty multidirectional male athletes performed 6 modified 505 (mod505) trials (3 left and right), and ground reaction forces were collected across the PEN and final foot contact (FINAL) during the change of direction. Pearson's correlation coefficients and coefficients of determination were used to explore the relationship between mechanical variables and mod505 completion time. Independent T-tests and Cohen's d effect sizes (ES) were conducted between faster (n = 10) and slower (n = 10) mod505 performers to explore differences in mechanical variables. Faster CODS performance was associated (p ≤ 0.05) with shorter GCTs (r = 0.701-0.757), greater horizontal propulsive forces (HPF) (r = -0.572 to -0.611), greater horizontal braking forces (HBF) in the PEN (r = -0.337), lower HBF ratios (r = -0.429), and lower FINAL vertical impact forces (VIF) (r = 0.449-0.559). Faster athletes demonstrated significantly (p ≤ 0.05, ES = 1.08-2.54) shorter FINAL GCTs, produced lower VIF, lower HBF ratios, and greater HPF in comparison to slower athletes. These findings suggest that different mechanical properties are required to produce faster CODS performance, with differences in mechanical properties observed between fast and slower performers. Furthermore, applying a greater proportion of braking force during the PEN relative to the FINAL may be advantageous for turning performance.

Career Directions--Photonics Technician

ERIC Educational Resources Information Center

Moore, Pam

2012-01-01

Many of the advances in telecommunications and medicine are due to laser and fiber-optic technology. This technology has led to devices that provide faster and richer communication, advanced surgeries, and faster healing times, as well as amazing robotics for manufacturing. But, as with all equipment, someone has to install and maintain it. That…

The effects of an editor serving as one of the reviewers during the peer-review process.

PubMed

Giordan, Marco; Csikasz-Nagy, Attila; Collings, Andrew M; Vaggi, Federico

2016-01-01

Background Publishing in scientific journals is one of the most important ways in which scientists disseminate research to their peers and to the wider public. Pre-publication peer review underpins this process, but peer review is subject to various criticisms and is under pressure from growth in the number of scientific publications. Methods Here we examine an element of the editorial process at eLife , in which the Reviewing Editor usually serves as one of the referees, to see what effect this has on decision times, decision type, and the number of citations. We analysed a dataset of 8,905 research submissions to eLife since June 2012, of which 2,747 were sent for peer review. This subset of 2747 papers was then analysed in detail.   Results The Reviewing Editor serving as one of the peer reviewers results in faster decision times on average, with the time to final decision ten days faster for accepted submissions (n=1,405) and five days faster for papers that were rejected after peer review (n=1,099). Moreover, editors acting as reviewers had no effect on whether submissions were accepted or rejected, and a very small (but significant) effect on citation rates. Conclusions An important aspect of eLife 's peer-review process is shown to be effective, given that decision times are faster when the Reviewing Editor serves as a reviewer. Other journals hoping to improve decision times could consider adopting a similar approach.

Fast rise times and the physical mechanism of deep earthquakes

NASA Technical Reports Server (NTRS)

Houston, H.; Williams, Q.

1991-01-01

A systematic global survey of the rise times and stress drops of deep and intermediate earthquakes is reported. When the rise times are scaled to the seismic moment release of the events, their average is nearly twice as fast for events deeper than about 450 km as for shallower events.

CHARACTERISTICS OF A FAST RISE TIME POWER SUPPLY FOR A PULSED PLASMA REACTOR FOR CHEMICAL VAPOR DESTRUCTION

EPA Science Inventory

Rotating spark gap devices for switching high-voltage direct current (dc) into a corona plasma reactor can achieve pulse rise times in the range of tens of nanoseconds. The fast rise times lead to vigorous plasma generation without sparking at instantaneous applied voltages highe...

Detection of Sound Rise Time by Adults with Dyslexia

ERIC Educational Resources Information Center

Hamalainen, J.; Leppanen, P.H.T.; Torppa, M.; Muller, K.; Lyytinen, H.

2005-01-01

Low sensitivity to amplitude modulated (AM) sounds is reported to be associated with dyslexia. An important aspect of amplitude modulation cycles are the rise and fall times within the sound. In this study, simplified stimuli equivalent to just one cycle were used and sensitivity to varying rise times was explored. Adult participants with dyslexia…

Regional sea level projections with observed gauge, altimeter and reconstructed data along China coast

NASA Astrophysics Data System (ADS)

Du, L.; Shi, H.; Zhang, S.

2017-12-01

Acting as the typical shelf seas in northwest Pacific Ocean, regional sea level along China coasts exhibits complicated and multiscale spatial-temporal characteristics under circumstance of global change. In this paper, sea level variability is investigated with tide gauges records, satellite altimetry data, reconstructed sea surface height, and CMIP simulation fields. Sea level exhibits the interannual variability imposing on a remarkable sea level rising in the China seas and coastal region, although its seasonal signals are significant as the results of global ocean. Sea level exhibits faster rising rate during the satellite altimetry era, nearly twice to the rate during the last sixty years. AVISO data and reconstructed sea surface heights illustrate good correlation coefficient, more than 0.8. Interannual sea level variation is mainly modulated by the low-frequency variability of wind fields over northern Pacific Ocean by local and remote processes. Meanwhile sea level varies obviously by the transport fluctuation and bimodality path of Kuroshio. Its variability possibly linked to internal variability of the ocean-atmosphere system influenced by ENSO oscillation. China Sea level have been rising during the 20th century, and are projected to continue to rise during this century. Sea level can reach the highest extreme level in latter half of 21st century. Modeled sea level including regional sea level projection combined with the IPCC climate scenarios play a significant role on coastal storm surge evolution. The vulnerable regions along the ECS coast will suffer from the increasing storm damage with sea level variations.

The Brahmaputra delta and its merger into an accretion wedge in advance of the progressive suturing between India and Asia

NASA Astrophysics Data System (ADS)

Seeber, L.; Ferguson, E. K.; Akhter, S. H.; Steckler, M. S.; Mondal, D. R.; Gale, J.; McHugh, C. M.; Paola, C.; Goodbred, S. L.

2013-12-01

The Tsangpo-Brahmaputra River is coupled with the progressive suturing of continental India with continental Asia. Since the Eocene onset of this ongoing collision, the delta of this river has advanced along the Indian margin in front of the suture. As the collision lifts the suture above sea level, progradation has kept the delta ahead of it, at sea level. The delta itself is confined between the still passive Indian continental margin and the advancing subduction boundary. Within this transition zone, the accretion prismof the active margin advanced progressively onto the delta and transformed it from a subsiding sediment sink to a rising and folding sediment source. The faster the accretionary prism grows, the faster the delta progrades to find new accommodation space; on the other hand, the prism advances faster upstream of the delta front where it finds more sediment to accrete. The strong mutual dependency of these processes represents a delicately balanced feedback between tectonics and sedimentation. The shape of the margin of India before and after the birth of the Dauki-Shillong structure modulates this interaction. We highlight this coupling between tectonics and sedimentation by examining structure and stratigraphy in the active foldbelt close to the current delta in Bangladesh and eastern India using field and published subsurface data. Insights include: 1) The shift of the Dauki boundary from a passive margin to a south-verging blind-thrust front is marked by a Quaternary foredeep. Foredeep growth buried along its axis formerly breached and eroded anticlines. Progressive growth of the buried Dauki fault has exposed this unconformity along the northern flank of the foredeep. 2) The rise and northward tilt of the Shillong/Dauki thrust-anticline during Quaternary is probably the cause of the Brahmaputra River avulsing from east of the massif to north and west of it. The Naga collision and the differential growth of the foldbelt south of the Dauki Fault predate the rise of the massif and the avulsion. 3) The foldbelt widens forming a 'promontory' into the active delta, about 100 km north of the coastline. The outer few anticlines have low amplitudes and no or partial surface expressions, yet they root below several km of sediment. Fault-bend models also require much more shortening than the folding can account for. These properties suggest substantial layer-parallel shortening ahead of the folding. 4) Rhythmic sandstone-shale beds characterize a particularly competent part of the stratigraphy of eroding anticlines in different parts of the foldbelt. We interpret them as seasonal facies changes in foreset sequences of the delta. The position of these ridge-forming beds would thus mark the southwestward advance of the delta preceding the folds and can be used to guide research into the role of structure and stratigraphy in the severe landslide hazard affecting development in the foldbelt (e.g., Aizawl, Mizoram State).

Rise time analysis of pulsed klystron-modulator for efficiency improvement of linear colliders

NASA Astrophysics Data System (ADS)

Oh, J. S.; Cho, M. H.; Namkung, W.; Chung, K. H.; Shintake, T.; Matsumoto, H.

2000-04-01

In linear accelerators, the periods during the rise and fall of a klystron-modulator pulse cannot be used to generate RF power. Thus, these periods need to be minimized to get high efficiency, especially in large-scale machines. In this paper, we present a simplified and generalized voltage rise time function of a pulsed modulator with a high-power klystron load using the equivalent circuit analysis method. The optimum pulse waveform is generated when this pulsed power system is tuned with a damping factor of ˜0.85. The normalized rise time chart presented in this paper allows one to predict the rise time and pulse shape of the pulsed power system in general. The results can be summarized as follows: The large distributed capacitance in the pulse tank and operating parameters, Vs× Tp , where Vs is load voltage and Tp is the pulse width, are the main factors determining the pulse rise time in the high-power RF system. With an RF pulse compression scheme, up to ±3% ripple of the modulator voltage is allowed without serious loss of compressor efficiency, which allows the modulator efficiency to be improved as well. The wiring inductance should be minimized to get the fastest rise time.

Delivering Faster Congestion Feedback with the Mark-Front Strategy

NASA Technical Reports Server (NTRS)

Liu, Chunlei; Jain, Raj

2001-01-01

Computer networks use congestion feedback from the routers and destinations to control the transmission load. Delivering timely congestion feedback is essential to the performance of networks. Reaction to the congestion can be more effective if faster feedback is provided. Current TCP/IP networks use timeout, duplicate Acknowledgement Packets (ACKs) and explicit congestion notification (ECN) to deliver the congestion feedback, each provides a faster feedback than the previous method. In this paper, we propose a markfront strategy that delivers an even faster congestion feedback. With analytical and simulation results, we show that mark-front strategy reduces buffer size requirement, improves link efficiency and provides better fairness among users. Keywords: Explicit Congestion Notification, mark-front, congestion control, buffer size requirement, fairness.

Evaluation of wind-induced internal pressure in low-rise buildings: A multi scale experimental and numerical approach

NASA Astrophysics Data System (ADS)

Tecle, Amanuel Sebhatu

Hurricane is one of the most destructive and costly natural hazard to the built environment and its impact on low-rise buildings, particularity, is beyond acceptable. The major objective of this research was to perform a parametric evaluation of internal pressure (IP) for wind-resistant design of low-rise buildings and wind-driven natural ventilation applications. For this purpose, a multi-scale experimental, i.e. full-scale at Wall of Wind (WoW) and small-scale at Boundary Layer Wind Tunnel (BLWT), and a Computational Fluid Dynamics (CFD) approach was adopted. This provided new capability to assess wind pressures realistically on internal volumes ranging from small spaces formed between roof tiles and its deck to attic to room partitions. Effects of sudden breaching, existing dominant openings on building envelopes as well as compartmentalization of building interior on the IP were systematically investigated. Results of this research indicated: (i) for sudden breaching of dominant openings, the transient overshooting response was lower than the subsequent steady state peak IP and internal volume correction for low-wind-speed testing facilities was necessary. For example a building without volume correction experienced a response four times faster and exhibited 30--40% lower mean and peak IP; (ii) for existing openings, vent openings uniformly distributed along the roof alleviated, whereas one sided openings aggravated the IP; (iii) larger dominant openings exhibited a higher IP on the building envelope, and an off-center opening on the wall exhibited (30--40%) higher IP than center located openings; (iv) compartmentalization amplified the intensity of IP and; (v) significant underneath pressure was measured for field tiles, warranting its consideration during net pressure evaluations. The study aimed at wind driven natural ventilation indicated: (i) the IP due to cross ventilation was 1.5 to 2.5 times higher for Ainlet/Aoutlet>1 compared to cases where Ainlet/Aoutlet<1, this in effect reduced the mixing of air inside the building and hence the ventilation effectiveness; (ii) the presence of multi-room partitioning increased the pressure differential and consequently the air exchange rate. Overall good agreement was found between the observed large-scale, small-scale and CFD based IP responses. Comparisons with ASCE 7-10 consistently demonstrated that the code underestimated peak positive and suction IP.

Logistics of air medical transport: When and where does helicopter transport reduce prehospital time for trauma?

PubMed

Chen, Xilin; Gestring, Mark L; Rosengart, Matthew R; Peitzman, Andrew B; Billiar, Timothy R; Sperry, Jason L; Brown, Joshua B

2018-05-04

Trauma is a time sensitive disease. Helicopter emergency medical services (HEMS) have shown benefit over ground EMS (GEMS), which may be related to reduced prehospital time. The distance at which this time benefit emerges depends on many factors that can vary across regions. Our objective was to determine the threshold distance at which HEMS has shorter prehospital time than GEMS under different conditions. Patients in the PA trauma registry 2000-2013 were included. Distance between zip centroid and trauma center was calculated using straight-line distance for HEMS and driving distance from GIS network analysis for GEMS. Contrast margins from linear regression identified the threshold distance at which HEMS had a significantly lower prehospital time than GEMS, indicated by non-overlapping 95% confidence intervals. The effect of peak traffic times and adverse weather on the threshold distance was evaluated. Geographic effects across EMS regions were also evaluated. A total of 144,741 patients were included with 19% transported by HEMS. Overall, HEMS became faster than GEMS at 7.7miles from the trauma center (p=0.043). HEMS became faster at 6.5miles during peak traffic (p=0.025) compared to 7.9miles during off-peak traffic (p=0.048). Adverse weather increased the distance at which HEMS was faster to 17.1miles (p=0.046) from 7.3miles in clear weather (p=0.036). Significant variation occurred across EMS regions, with threshold distances ranging from 5.4miles to 35.3miles. There was an inverse but non-significant relationship between urban population and threshold distance across EMS regions (ρ -0.351, p=0.28). This is the first study to demonstrate that traffic, weather, and geographic region significantly impact the threshold distance at which HEMS is faster than GEMS. HEMS was faster at shorter distances during peak traffic while adverse weather increased this distance. The threshold distance varied widely across geographic region. These factors must be considered to guide appropriate HEMS triage protocols. III, Therapeutic.

Simultaneous development of laparoscopy and robotics provides acceptable perioperative outcomes and shows robotics to have a faster learning curve and to be overall faster in rectal cancer surgery: analysis of novice MIS surgeon learning curves.

PubMed

Melich, George; Hong, Young Ki; Kim, Jieun; Hur, Hyuk; Baik, Seung Hyuk; Kim, Nam Kyu; Sender Liberman, A; Min, Byung Soh

2015-03-01

Laparoscopy offers some evidence of benefit compared to open rectal surgery. Robotic rectal surgery is evolving into an accepted approach. The objective was to analyze and compare laparoscopic and robotic rectal surgery learning curves with respect to operative times and perioperative outcomes for a novice minimally invasive colorectal surgeon. One hundred and six laparoscopic and 92 robotic LAR rectal surgery cases were analyzed. All surgeries were performed by a surgeon who was primarily trained in open rectal surgery. Patient characteristics and perioperative outcomes were analyzed. Operative time and CUSUM plots were used for evaluating the learning curve for laparoscopic versus robotic LAR. Laparoscopic versus robotic LAR outcomes feature initial group operative times of 308 (291-325) min versus 397 (373-420) min and last group times of 220 (212-229) min versus 204 (196-211) min-reversed in favor of robotics; major complications of 4.7 versus 6.5 % (NS), resection margin involvement of 2.8 versus 4.4 % (NS), conversion rate of 3.8 versus 1.1 (NS), lymph node harvest of 16.3 versus 17.2 (NS), and estimated blood loss of 231 versus 201 cc (NS). Due to faster learning curves for extracorporeal phase and total mesorectal excision phase, the robotic surgery was observed to be faster than laparoscopic surgery after the initial 41 cases. CUSUM plots demonstrate acceptable perioperative surgical outcomes from the beginning of the study. Initial robotic operative times improved with practice rapidly and eventually became faster than those for laparoscopy. Developing both laparoscopic and robotic skills simultaneously can provide acceptable perioperative outcomes in rectal surgery. It might be suggested that in the current milieu of clashing interests between evolving technology and economic constrains, there might be advantages in embracing both approaches.

Improving Depth, Energy and Timing Estimation in PET Detectors with Deconvolution and Maximum Likelihood Pulse Shape Discrimination

PubMed Central

Berg, Eric; Roncali, Emilie; Hutchcroft, Will; Qi, Jinyi; Cherry, Simon R.

2016-01-01

In a scintillation detector, the light generated in the scintillator by a gamma interaction is converted to photoelectrons by a photodetector and produces a time-dependent waveform, the shape of which depends on the scintillator properties and the photodetector response. Several depth-of-interaction (DOI) encoding strategies have been developed that manipulate the scintillator’s temporal response along the crystal length and therefore require pulse shape discrimination techniques to differentiate waveform shapes. In this work, we demonstrate how maximum likelihood (ML) estimation methods can be applied to pulse shape discrimination to better estimate deposited energy, DOI and interaction time (for time-of-flight (TOF) PET) of a gamma ray in a scintillation detector. We developed likelihood models based on either the estimated detection times of individual photoelectrons or the number of photoelectrons in discrete time bins, and applied to two phosphor-coated crystals (LFS and LYSO) used in a previously developed TOF-DOI detector concept. Compared with conventional analytical methods, ML pulse shape discrimination improved DOI encoding by 27% for both crystals. Using the ML DOI estimate, we were able to counter depth-dependent changes in light collection inherent to long scintillator crystals and recover the energy resolution measured with fixed depth irradiation (~11.5% for both crystals). Lastly, we demonstrated how the Richardson-Lucy algorithm, an iterative, ML-based deconvolution technique, can be applied to the digitized waveforms to deconvolve the photodetector’s single photoelectron response and produce waveforms with a faster rising edge. After deconvolution and applying DOI and time-walk corrections, we demonstrated a 13% improvement in coincidence timing resolution (from 290 to 254 ps) with the LFS crystal and an 8% improvement (323 to 297 ps) with the LYSO crystal. PMID:27295658

Improving Depth, Energy and Timing Estimation in PET Detectors with Deconvolution and Maximum Likelihood Pulse Shape Discrimination.

PubMed

Berg, Eric; Roncali, Emilie; Hutchcroft, Will; Qi, Jinyi; Cherry, Simon R

2016-11-01

In a scintillation detector, the light generated in the scintillator by a gamma interaction is converted to photoelectrons by a photodetector and produces a time-dependent waveform, the shape of which depends on the scintillator properties and the photodetector response. Several depth-of-interaction (DOI) encoding strategies have been developed that manipulate the scintillator's temporal response along the crystal length and therefore require pulse shape discrimination techniques to differentiate waveform shapes. In this work, we demonstrate how maximum likelihood (ML) estimation methods can be applied to pulse shape discrimination to better estimate deposited energy, DOI and interaction time (for time-of-flight (TOF) PET) of a gamma ray in a scintillation detector. We developed likelihood models based on either the estimated detection times of individual photoelectrons or the number of photoelectrons in discrete time bins, and applied to two phosphor-coated crystals (LFS and LYSO) used in a previously developed TOF-DOI detector concept. Compared with conventional analytical methods, ML pulse shape discrimination improved DOI encoding by 27% for both crystals. Using the ML DOI estimate, we were able to counter depth-dependent changes in light collection inherent to long scintillator crystals and recover the energy resolution measured with fixed depth irradiation (~11.5% for both crystals). Lastly, we demonstrated how the Richardson-Lucy algorithm, an iterative, ML-based deconvolution technique, can be applied to the digitized waveforms to deconvolve the photodetector's single photoelectron response and produce waveforms with a faster rising edge. After deconvolution and applying DOI and time-walk corrections, we demonstrated a 13% improvement in coincidence timing resolution (from 290 to 254 ps) with the LFS crystal and an 8% improvement (323 to 297 ps) with the LYSO crystal.

Effect of the Ethanol Injection Moment During Compression Stroke on the Combustion of Ethanol - Diesel Dual Direct Injection Engine

NASA Astrophysics Data System (ADS)

Liang, Yu; Zhou, Liying; Huang, Haomin; Xu, Mingfei; Guo, Mei; Chen, Xin

2018-01-01

A set of GDI system is installed on a F188 single-cylinder, air-cooled and direct injection diesel engine, which is used for ethanol injection, with the injection time controlled by the crank angle signal collected by AVL angle encoder. The injection of ethanol amounts to half of the thermal equivalent of an original diesel fuel. A 3D combustion model is established for the ethanol - diesel dual direct injection engine. Diesel was injected from the original fuel injection system, with a fuel supply advance angle of 20°CA. The ethanol was injected into the cylinder during compression process. Diesel injection began after the completion of ethanol injection. Ethanol injection starting point of 240°CA, 260°CA, 280°CA, 300°CA and 319.4°CA were simulated and analyzed. Due to the different timing of ethanol injection, the ignition of the ethanol mixture when diesel fires, results in non-uniform ignition distribution and flame propagation rate, since the distribution and concentration gradients of the ethanol mixture in the cylinder are different, thus affecting the combustion process. The results show that, when ethanol is injected at 319.4°CA, the combustion heat release rate and the pressure rise rate during the initial stage are the highest. Also, the maximum combustion pressure, with a relatively advance phase, is the highest. In case of later initial ethanol injection, the average temperature in the cylinder during the initial combustion period will have a faster rise. In case of initial injection at 319.4°CA, the average temperature in the cylinder is the highest, followed by 240°CA ethanol injection. In the post-combustion stage, the earlier ethanol injection will result in higher average temperature in the cylinder and more complete fuel combustion. The injection of ethanol at 319.4°CA produces earlier and highest NOX emissions.

On the Importance of Cycle Minimum in Sunspot Cycle Prediction

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1996-01-01

The characteristics of the minima between sunspot cycles are found to provide important information for predicting the amplitude and timing of the following cycle. For example, the time of the occurrence of sunspot minimum sets the length of the previous cycle, which is correlated by the amplitude-period effect to the amplitude of the next cycle, with cycles of shorter (longer) than average length usually being followed by cycles of larger (smaller) than average size (true for 16 of 21 sunspot cycles). Likewise, the size of the minimum at cycle onset is correlated with the size of the cycle's maximum amplitude, with cycles of larger (smaller) than average size minima usually being associated with larger (smaller) than average size maxima (true for 16 of 22 sunspot cycles). Also, it was found that the size of the previous cycle's minimum and maximum relates to the size of the following cycle's minimum and maximum with an even-odd cycle number dependency. The latter effect suggests that cycle 23 will have a minimum and maximum amplitude probably larger than average in size (in particular, minimum smoothed sunspot number Rm = 12.3 +/- 7.5 and maximum smoothed sunspot number RM = 198.8 +/- 36.5, at the 95-percent level of confidence), further suggesting (by the Waldmeier effect) that it will have a faster than average rise to maximum (fast-rising cycles have ascent durations of about 41 +/- 7 months). Thus, if, as expected, onset for cycle 23 will be December 1996 +/- 3 months, based on smoothed sunspot number, then the length of cycle 22 will be about 123 +/- 3 months, inferring that it is a short-period cycle and that cycle 23 maximum amplitude probably will be larger than average in size (from the amplitude-period effect), having an RM of about 133 +/- 39 (based on the usual +/- 30 percent spread that has been seen between observed and predicted values), with maximum amplitude occurrence likely sometime between July 1999 and October 2000.

Drought responses of two gymnosperm species with contrasting stomatal regulation strategies under elevated [CO2] and temperature.

PubMed

Duan, Honglang; O'Grady, Anthony P; Duursma, Remko A; Choat, Brendan; Huang, Guomin; Smith, Renee A; Jiang, Yanan; Tissue, David T

2015-07-01

Future climate regimes characterized by rising [CO2], rising temperatures and associated droughts may differentially affect tree growth and physiology. However, the interactive effects of these three factors are complex because elevated [CO2] and elevated temperature may generate differential physiological responses during drought. To date, the interactive effects of elevated [CO2] and elevated temperature on drought-induced tree mortality remain poorly understood in gymnosperm species that differ in stomatal regulation strategies. Water relations and carbon dynamics were examined in two species with contrasting stomatal regulation strategies: Pinus radiata D. Don (relatively isohydric gymnosperm; regulating stomata to maintain leaf water potential above critical thresholds) and Callitris rhomboidea R. Br (relatively anisohydric gymnosperm; allowing leaf water potential to decline as the soil dries), to assess response to drought as a function of [CO2] and temperature. Both species were grown in two [CO2] (C(a) (ambient, 400 μl l(-1)) and C(e) (elevated, 640 μl l(-1))) and two temperature (T(a) (ambient) and T(e) (ambient +4 °C)) treatments in a sun-lit glasshouse under well-watered conditions. Drought plants were then exposed to a progressive drought until mortality. Prior to mortality, extensive xylem cavitation occurred in both species, but significant depletion of non-structural carbohydrates was not observed in either species. Te resulted in faster mortality in P. radiata, but it did not modify the time-to-mortality in C. rhomboidea. C(e) did not delay the time-to-mortality in either species under drought or T(e) treatments. In summary, elevated temperature (+4 °C) had greater influence than elevated [CO2] (+240 μl l(-1)) on drought responses of the two studied gymnosperm species, while stomatal regulation strategies did not generally affect the relative contributions of hydraulic failure and carbohydrate depletion to mortality under severe drought. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Paired Synchronous Rhythmic Finger Tapping without an External Timing Cue Shows Greater Speed Increases Relative to Those for Solo Tapping

PubMed Central

Okano, Masahiro; Shinya, Masahiro; Kudo, Kazutoshi

2017-01-01

In solo synchronization-continuation (SC) tasks, intertap intervals (ITI) are known to drift from the initial tempo. It has been demonstrated that people in paired and group contexts modulate their action timing unconsciously in various situations such as choice reaction tasks, rhythmic body sway, and hand clapping in concerts, which suggests the possibility that ITI drift is also affected by paired context. We conducted solo and paired SC tapping experiments with three tempos (75, 120, and 200 bpm) and examined whether tempo-keeping performance changed according to tempo and/or the number of players. Results indicated that those tapping in the paired conditions were faster, relative to those observed in the solo conditions, for all tempos. For the faster participants, the degree of ITI drift in the solo conditions was strongly correlated with that in the paired conditions. Regression analyses suggested that both faster and slower participants adapted their tap timing to that of their partners. A possible explanation for these results is that the participants reset the phase of their internal clocks according to the faster beat between their own tap and the partners’ tap. Our results indicated that paired context could bias the direction of ITI drift toward decreasing. PMID:28276461

Paired Synchronous Rhythmic Finger Tapping without an External Timing Cue Shows Greater Speed Increases Relative to Those for Solo Tapping.

PubMed

Okano, Masahiro; Shinya, Masahiro; Kudo, Kazutoshi

2017-03-09

In solo synchronization-continuation (SC) tasks, intertap intervals (ITI) are known to drift from the initial tempo. It has been demonstrated that people in paired and group contexts modulate their action timing unconsciously in various situations such as choice reaction tasks, rhythmic body sway, and hand clapping in concerts, which suggests the possibility that ITI drift is also affected by paired context. We conducted solo and paired SC tapping experiments with three tempos (75, 120, and 200 bpm) and examined whether tempo-keeping performance changed according to tempo and/or the number of players. Results indicated that those tapping in the paired conditions were faster, relative to those observed in the solo conditions, for all tempos. For the faster participants, the degree of ITI drift in the solo conditions was strongly correlated with that in the paired conditions. Regression analyses suggested that both faster and slower participants adapted their tap timing to that of their partners. A possible explanation for these results is that the participants reset the phase of their internal clocks according to the faster beat between their own tap and the partners' tap. Our results indicated that paired context could bias the direction of ITI drift toward decreasing.

Ames Lab 101: Ultrafast Magnetic Switching

ScienceCinema

Wang; Jigang

2018-01-01

Ames Laboratory physicists have found a new way to switch magnetism that is at least 1000 times faster than currently used in magnetic memory technologies. Magnetic switching is used to encode information in hard drives, magnetic random access memory and other computing devices. The discovery potentially opens the door to terahertz and faster memory speeds.

Incidental learning speeds visual search by lowering response thresholds, not by improving efficiency: evidence from eye movements.

PubMed

Hout, Michael C; Goldinger, Stephen D

2012-02-01

When observers search for a target object, they incidentally learn the identities and locations of "background" objects in the same display. This learning can facilitate search performance, eliciting faster reaction times for repeated displays. Despite these findings, visual search has been successfully modeled using architectures that maintain no history of attentional deployments; they are amnesic (e.g., Guided Search Theory). In the current study, we asked two questions: 1) under what conditions does such incidental learning occur? And 2) what does viewing behavior reveal about the efficiency of attentional deployments over time? In two experiments, we tracked eye movements during repeated visual search, and we tested incidental memory for repeated nontarget objects. Across conditions, the consistency of search sets and spatial layouts were manipulated to assess their respective contributions to learning. Using viewing behavior, we contrasted three potential accounts for faster searching with experience. The results indicate that learning does not result in faster object identification or greater search efficiency. Instead, familiar search arrays appear to allow faster resolution of search decisions, whether targets are present or absent.

Rapid thinning and collapse of lake calving Yakutat Glacier, Southeast Alaska

NASA Astrophysics Data System (ADS)

Trussel, Barbara Lea

Glaciers around the globe are experiencing a notable retreat and thinning, triggered by atmospheric warming. Tidewater glaciers in particular have received much attention, because they have been recognized to contribute substantially to global sea level rise. However, lake calving glaciers in Alaska show increasingly high thinning and retreat rates and are therefore contributors to sea level rise. The number of such lake calving systems is increasing worldwide as land-terminating glaciers retreat into overdeepened basins and form proglacial lakes. Yakutat Glacier in Southeast Alaska is a low elevation lake calving glacier with an accumulation to total area ratio of 0.03. It experienced rapid thinning of 4.43 +/- 0.06 m w.e. yr-1 between 2000-2010 and terminus retreat of over 15 km since the beginning of the 20th century. Simultaneously, adjacent Yakutat Icefield land-terminating glaciers thinned at lower but still substantial rates (3.54 +/- 0.06 m w.e. yr -1 for the same time period), indicating lake calving dynamics help drive increased mass loss. Yakutat Glacier sustained a ˜3 km long floating tongue for over a decade, which started to disintegrate into large tabular icebergs in 2010. Such floating tongues are rarely seen on temperate tidewater glaciers. The floating ice was weakened by surface ablation, which then allowed rifts to form and intersect. Ice velocity from GPS measurements showed that the ice on the floating tongue was moving substantially faster than grounded ice, which was attributed to rift opening between the floating and grounded ice. Temporal variations of rift opening were determined from time-lapse imagery, and correlated well with variations in ice speeds. Larger rift opening rates occurred during and after precipitation or increased melt episodes. Both of these events increased subglacial discharge and could potentially increase the subaqueous currents towards the open lake and thus increase drag on the ice underside. Simultaneously, increased water input may cause lake level in rifts to rise resulting in faster rift propagation and spreading. Similar formation and disintegration of floating tongues are expected to occur in the glacier's future, as the ice divide lies below the current lake level. In addition to calving retreat, Yakutat Glacier is rapidly thinning, which lowers its surface and therefore exposes the ice to warmer air temperatures causing increased thinning. Even under a constant climate, this positive feedback mechanism would force Yakutat Glacier to quickly retreat and mostly disappear. Simulations of future mass loss were run for two scenarios, keeping the current climate and forcing it with a projected warming climate. Results showed that over 95% of the glacier ice will have disappeared by 2120 or 2070 under a constant vs projected climate, respectively. For the first few decades, the glacier will be able to maintain its current thinning rate by retreating and thus losing areas of lowest elevation. However, once higher elevations have thinned substantially, the glacier cannot compensate any more to maintain a constant thinning rate and transfers into an unstable run-away situation. To stop this collapse and transform Yakutat Glacier into equilibrium in its current geometry, air temperatures would have to drop by 1.5 K or precipitation would have to increase by more than 50%. An increase in precipitation alone is unlikely to lead to a stable configuration, due to the very small current accumulation area.

Analysis of United States’ Broadband Policy

DTIC Science & Technology

2007-03-01

compared with the minimum speed the FCC uses in its definition of broadband access. For example, using a 56K modem connection to download a 10...transmission rates multiple times faster than a 56K modem , users can view video or download software and other data-intensive files in a matter of seconds...boast download speeds from 144Kbps (roughly three times faster than a 56K dial-up modem connection) to 2.4Mbps (close to cable- modem speed). Although

Two-Stage Centrifugal Fan

NASA Technical Reports Server (NTRS)

Converse, David

2011-01-01

Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

Temperature Effects on Force and Actin⁻Myosin Interaction in Muscle: A Look Back on Some Experimental Findings.

PubMed

Ranatunga, K W

2018-05-22

Observations made in temperature studies on mammalian muscle during force development, shortening, and lengthening, are re-examined. The isometric force in active muscle goes up substantially on warming from less than 10 °C to temperatures closer to physiological (>30 °C), and the sigmoidal temperature dependence of this force has a half-maximum at ~10 °C. During steady shortening, when force is decreased to a steady level, the sigmoidal curve is more pronounced and shifted to higher temperatures, whereas, in lengthening muscle, the curve is shifted to lower temperatures, and there is a less marked increase with temperature. Even with a small rapid temperature-jump (T-jump), force in active muscle rises in a definitive way. The rate of tension rise is slower with adenosine diphosphate (ADP) and faster with increased phosphate. Analysis showed that a T-jump enhances an early, pre-phosphate release step in the acto-myosin (crossbridge) ATPase cycle, thus inducing a force-rise. The sigmoidal dependence of steady force on temperature is due to this endothermic nature of crossbridge force generation. During shortening, the force-generating step and the ATPase cycle are accelerated, whereas during lengthening, they are inhibited. The endothermic force generation is seen in different muscle types (fast, slow, and cardiac). The underlying mechanism may involve a structural change in attached myosin heads and/or their attachments on heat absorption.

Temperature Effects on Force and Actin–Myosin Interaction in Muscle: A Look Back on Some Experimental Findings

PubMed Central

Ranatunga, K. W.

2018-01-01

Observations made in temperature studies on mammalian muscle during force development, shortening, and lengthening, are re-examined. The isometric force in active muscle goes up substantially on warming from less than 10 °C to temperatures closer to physiological (>30 °C), and the sigmoidal temperature dependence of this force has a half-maximum at ~10 °C. During steady shortening, when force is decreased to a steady level, the sigmoidal curve is more pronounced and shifted to higher temperatures, whereas, in lengthening muscle, the curve is shifted to lower temperatures, and there is a less marked increase with temperature. Even with a small rapid temperature-jump (T-jump), force in active muscle rises in a definitive way. The rate of tension rise is slower with adenosine diphosphate (ADP) and faster with increased phosphate. Analysis showed that a T-jump enhances an early, pre-phosphate release step in the acto-myosin (crossbridge) ATPase cycle, thus inducing a force-rise. The sigmoidal dependence of steady force on temperature is due to this endothermic nature of crossbridge force generation. During shortening, the force-generating step and the ATPase cycle are accelerated, whereas during lengthening, they are inhibited. The endothermic force generation is seen in different muscle types (fast, slow, and cardiac). The underlying mechanism may involve a structural change in attached myosin heads and/or their attachments on heat absorption. PMID:29786656

Assessment of physical function in adults with Prader-Willi syndrome.

PubMed

Sode-Carlsen, Rasmus; Farholt, Stense; Rabben, Kai Fr; Bollerslev, Jens; Sandahl Christiansen, Jens; Höybye, Charlotte

2009-01-01

To evaluate implementation of at test battery for assessing physical function in adults with Prader-Willi syndrome (PWS). Forty-three adults with PWS, 20 men and 23 women, mean age 29 +/- 9 years. Body mass index (BMI) and body composition were measured. A test battery a.m. Guralnik for standing balance, 2.4 m and 10 m walk and repeated rising from a chair was scored and evaluated. Mean BMI was 29.4 +/- 9.1 kg/m(2), body fat mass (FM) 26.0 +/- 16.1 kg. The adults with PWS managed the test battery well, and high scores were achieved for standing balance and 2.4 m walk. In contrast, only 13 managed maximum score in the repeated rising from a chair and 31 to walk 10 m for 6 s or faster. Significant correlations were seen between 2.4 m walk and FM ( p = 0.041) and between 10 m walk and BMI ( p = 0.001) and FM ( p = 0.019). Repeated rising from a chair and 10 m walk are useful assessments in clinical practice to identify adults with PWS with reduced physical function. Reduced performance was related to higher BMI and FM emphasising the importance of efforts to keep normal body weight and body composition in adults with PWS. These measures might be useful in monitoring effects of intervention.

Precise rise and decay time measurements of inorganic scintillators by means of X-ray and 511 keV excitation

NASA Astrophysics Data System (ADS)

Gundacker, S.; Turtos, R. M.; Auffray, E.; Lecoq, P.

2018-05-01

The emergence of new solid-state avalanche photodetectors, e.g. SiPMs, with unprecedented timing capabilities opens new ways to profit from ultrafast and prompt photon emission in scintillators. In time of flight positron emission tomography (TOF-PET) and high energy timing detectors based on scintillators the ultimate coincidence time resolution (CTR) achievable is proportional to the square root of the scintillation rise time, decay time and the reciprocal light yield, CTR ∝√{τrτd / LY }. Hence, the precise study of light emission in the very first tens of picoseconds is indispensable to understand time resolution limitations imposed by the scintillator. We developed a time correlated single photon counting setup having a Gaussian impulse response function (IRF) of 63ps sigma, allowing to precisely measure the scintillation rise time of various materials with 511keV excitation. In L(Y)SO:Ce we found two rise time components, the first below the resolution of our setup <10 ps and a second component being ∼380 ps. Co-doping with Ca2+ completely suppresses the slow rise component leading to a very fast initial scintillation emission with a rise time of <10ps. A very similar behavior is observed in LGSO:Ce crystals. The results are further confirmed by complementary measurements using a streak-camera system with pulsed X-ray excitation and additional 511 keV excited measurements of Mg2+ co-doped LuAG:Ce, YAG:Ce and GAGG:Ce samples.

Decadally cycling soil carbon is more sensitive to warming than faster-cycling soil carbon.

PubMed

Lin, Junjie; Zhu, Biao; Cheng, Weixin

2015-12-01

The response of soil organic carbon (SOC) pools to globally rising surface temperature crucially determines the feedback between climate change and the global carbon cycle. However, there is a lack of studies investigating the temperature sensitivity of decomposition for decadally cycling SOC which is the main component of total soil carbon stock and the most relevant to global change. We tackled this issue using two decadally (13) C-labeled soils and a much improved measuring system in a long-term incubation experiment. Results indicated that the temperature sensitivity of decomposition for decadally cycling SOC (>23 years in one soil and >55 years in the other soil) was significantly greater than that for faster-cycling SOC (<23 or 55 years) or for the entire SOC stock. Moreover, decadally cycling SOC contributed substantially (35-59%) to the total CO2 loss during the 360-day incubation. Overall, these results indicate that the decomposition of decadally cycling SOC is highly sensitive to temperature change, which will likely make this large SOC stock vulnerable to loss by global warming in the 21st century and beyond. © 2015 John Wiley & Sons Ltd.

Accelerated protein damage in brains of PIMT+/- mice; a possible model for the variability of cognitive decline in human aging.

PubMed

Qin, Zhenxia; Dimitrijevic, Aleksandra; Aswad, Dana W

2015-02-01

Isoaspartate formation is a common type of protein damage normally kept in check by the repair enzyme protein-L-isoaspartyl methyltransferase (PIMT). Mice with a knockout of the gene (Pcmt1) for this enzyme (KO, -/-) exhibit a pronounced neuropathology with fatal epileptic seizures at 30-60 days. Heterozygous (HZ, +/-) mice have 50% of the PIMT activity found in wild-type (WT, +/+) mice, but appear normal. To see if HZ mice exhibit accelerated aging at the molecular level, we compared brain extracts from HZ and WT mice at 8 months and 2 years with regard to PIMT activity, isoaspartate levels, and activity of an endogenous PIMT substrate, creatine kinase B. PIMT activity declined modestly with age in both genotypes. Isoaspartate was significantly higher in HZ than WT mice at 8 months and more so at 2 years, rising 5× faster in HZ males and 3× faster in females. Creatine kinase activity decreased with age and was always lower in the HZ mice. These findings suggest the individual variation of human PIMT levels may significantly influence the course of age-related central nervous system dysfunction. Copyright © 2015 Elsevier Inc. All rights reserved.

National health expenditure projections: modest annual growth until coverage expands and economic growth accelerates.

PubMed

Keehan, Sean P; Cuckler, Gigi A; Sisko, Andrea M; Madison, Andrew J; Smith, Sheila D; Lizonitz, Joseph M; Poisal, John A; Wolfe, Christian J

2012-07-01

For 2011-13, US health spending is projected to grow at 4.0 percent, on average--slightly above the historically low growth rate of 3.8 percent in 2009. Preliminary data suggest that growth in consumers' use of health services remained slow in 2011, and this pattern is expected to continue this year and next. In 2014, health spending growth is expected to accelerate to 7.4 percent as the major coverage expansions from the Affordable Care Act begin. For 2011 through 2021, national health spending is projected to grow at an average rate of 5.7 percent annually, which would be 0.9 percentage point faster than the expected annual increase in the gross domestic product during this period. By 2021, federal, state, and local government health care spending is projected to be nearly 50 percent of national health expenditures, up from 46 percent in 2011, with federal spending accounting for about two-thirds of the total government share. Rising government spending on health care is expected to be driven by faster growth in Medicare enrollment, expanded Medicaid coverage, and the introduction of premium and cost-sharing subsidies for health insurance exchange plans.

Smart tissue anastomosis robot (STAR): a vision-guided robotics system for laparoscopic suturing.

PubMed

Leonard, Simon; Wu, Kyle L; Kim, Yonjae; Krieger, Axel; Kim, Peter C W

2014-04-01

This paper introduces the smart tissue anastomosis robot (STAR). Currently, the STAR is a proof-of-concept for a vision-guided robotic system featuring an actuated laparoscopic suturing tool capable of executing running sutures from image-based commands. The STAR tool is designed around a commercially available laparoscopic suturing tool that is attached to a custom-made motor stage and the STAR supervisory control architecture that enables a surgeon to select and track incisions and the placement of stitches. The STAR supervisory-control interface provides two modes: A manual mode that enables a surgeon to specify the placement of each stitch and an automatic mode that automatically computes equally-spaced stitches based on an incision contour. Our experiments on planar phantoms demonstrate that the STAR in either mode is more accurate, up to four times more consistent and five times faster than surgeons using state-of-the-art robotic surgical system, four times faster than surgeons using manual Endo360(°)®, and nine times faster than surgeons using manual laparoscopic tools.

49 CFR 173.127 - Class 5, Division 5.1-Definition and assignment of packing groups.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the UN Manual of Tests and Criteria, it spontaneously ignites or its mean time for a pressure rise... ignites when mixed with cellulose in a 1:1 ratio; or (B) Any material which exhibits a mean pressure rise time less than the pressure rise time of a 1:1 perchloric acid (50 percent)/cellulose mixture. (ii...

Weighting of Amplitude and Formant Rise Time Cues by School-Aged Children: A Mismatch Negativity Study

ERIC Educational Resources Information Center

Varghese, Peter; Kalashnikova, Marina; Burnham, Denis

2018-01-01

Purpose: An important skill in the development of speech perception is to apply optimal weights to acoustic cues so that phonemic information is recovered from speech with minimum effort. Here, we investigated the development of acoustic cue weighting of amplitude rise time (ART) and formant rise time (FRT) cues in children as measured by mismatch…

49 CFR 173.127 - Class 5, Division 5.1-Definition and assignment of packing groups.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the UN Manual of Tests and Criteria, it spontaneously ignites or its mean time for a pressure rise... ignites when mixed with cellulose in a 1:1 ratio; or (B) Any material which exhibits a mean pressure rise time less than the pressure rise time of a 1:1 perchloric acid (50 percent)/cellulose mixture. (ii...

Orbital Payload Reductions Resulting from Booster and Trajectory Modifications for Recovery of a Large Rocket Booster

NASA Technical Reports Server (NTRS)

Levin, Alan D.; Hopkins, Edward J.

1961-01-01

An analysis was made to determine the reduction in payload for a 300 nautical mile orbit resulting from the addition of inert weight, representing recovery gear, to the first-stage booster of a three-stage rocket vehicle. The values of added inert weight investigated ranged from 0 to 18 percent of gross weight at lift off. The study also included the effects on the payload in orbit and the distance from the launch site at burnout and at impact caused by variation in the vertical rise time before the programmed tilt. The vertical rise times investigated ranged from 16-7 to 100 percent of booster burning time. For a vertical rise of 16.7 percent of booster burning time it was found that a 50-percent increase in the weight of the empty booster resulted in only a 10-percent reduction of the payload in orbit. For no added booster weight, increasing vertical rise time from 16-7 to 100 percent of booster burning time (so that the spent booster would impact in the launch area) reduced the payload by 37 percent. Increasing the vertical rise time from 16-7 to 50 percent of booster burning time resulted in about a 15-percent reduction in the impact distance, and for vertical rise times greater than 50-percent the impact distance decreased rapidly.

Spatial coding of object typical size: evidence for a SNARC-like effect.

PubMed

Sellaro, Roberta; Treccani, Barbara; Job, Remo; Cubelli, Roberto

2015-11-01

The present study aimed to assess whether the representation of the typical size of objects can interact with response position codes in two-choice bimanual tasks, and give rise to a SNARC-like effect (faster responses when the representation of the typical size of the object to which the target stimulus refers corresponds to response side). Participants performed either a magnitude comparison task (in which they were required to judge whether the target was smaller or larger than a reference stimulus; Experiment 1) or a semantic decision task (in which they had to classify the target as belonging to either the category of living or non-living entities; Experiment 2). Target stimuli were pictures or written words referring to either typically large and small animals or inanimate objects. In both tasks, participants responded by pressing a left- or right-side button. Results showed that, regardless of the to-be-performed task (magnitude comparison or semantic decision) and stimulus format (picture or word), left responses were faster when the target represented typically small-sized entities, whereas right responses were faster for typically large-sized entities. These results provide evidence that the information about the typical size of objects is activated even if it is not requested by the task, and are consistent with the idea that objects' typical size is automatically spatially coded, as has been proposed to occur for number magnitudes. In this representation, small objects would be on the left and large objects would be on the right. Alternative interpretations of these results are also discussed.

Effect of feedback from a socially interactive humanoid robot on reaching kinematics in children with and without cerebral palsy: A pilot study.

PubMed

Chen, Yuping; Garcia-Vergara, Sergio; Howard, Ayanna M

2017-08-17

To examine whether children with or without cerebral palsy (CP) would follow a humanoid robot's (i.e., Darwin) feedback to move their arm faster when playing virtual reality (VR) games. Seven children with mild CP and 10 able-bodied children participated. Real-time reaching was evaluated by playing the Super Pop VR TM system, including 2-game baseline, 3-game acquisition, and another 2-game extinction. During acquisition, Darwin provided verbal feedback to direct the child to reach a kinematically defined target goal (i.e., 80% of average movement time in baseline). Outcome variables included the percentage of successful reaches ("% successful reaches"), movement time (MT), average speed, path, and number of movement units. All games during acquisition and extinction had larger "%successful reaches," faster speeds, and faster MTs than the 2 games during baseline (p < .05). Children with and without CP could follow the robot's feedback for changing their reaching kinematics when playing VR games.

Faster sequence homology searches by clustering subsequences.

PubMed

Suzuki, Shuji; Kakuta, Masanori; Ishida, Takashi; Akiyama, Yutaka

2015-04-15

Sequence homology searches are used in various fields. New sequencing technologies produce huge amounts of sequence data, which continuously increase the size of sequence databases. As a result, homology searches require large amounts of computational time, especially for metagenomic analysis. We developed a fast homology search method based on database subsequence clustering, and implemented it as GHOSTZ. This method clusters similar subsequences from a database to perform an efficient seed search and ungapped extension by reducing alignment candidates based on triangle inequality. The database subsequence clustering technique achieved an ∼2-fold increase in speed without a large decrease in search sensitivity. When we measured with metagenomic data, GHOSTZ is ∼2.2-2.8 times faster than RAPSearch and is ∼185-261 times faster than BLASTX. The source code is freely available for download at http://www.bi.cs.titech.ac.jp/ghostz/ akiyama@cs.titech.ac.jp Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press.

Implications on 1+1 D runup modeling due to time features of the earthquake source

NASA Astrophysics Data System (ADS)

Fuentes, M.; Riquelme, S.; Campos, J. A.

2017-12-01

The time characteristics of the seismic source are usually neglected in tsunami modeling, due to the difference in the time scale of both processes. Nonetheless, there are just a few analytical studies that intended to explain separately the role of the rise time and the rupture velocity. In this work, we extend an analytical 1+1D solution for the shoreline motion time series, from the static case to the dynamic case, by including both, rise time and rupture velocity. Results show that the static case correspond to a limit case of null rise time and infinite rupture velocity. Both parameters contribute in shifting the arrival time, but maximum run-up may be affected by very slow ruptures and long rise time. The analytical solution has been tested for the Nicaraguan tsunami earthquake, suggesting that the rupture was not slow enough to cause wave amplification to explain the high runup observations.

The role of interplanetary shock orientation on SC/SI rise time and geoeffectiveness

NASA Astrophysics Data System (ADS)

Selvakumaran, R.; Veenadhari, B.; Ebihara, Y.; Kumar, Sandeep; Prasad, D. S. V. V. D.

2017-03-01

Interplanetary (IP) shocks interact with the Earth's magnetosphere, resulting in compression of the magnetosphere which in turn increases the Earth's magnetic field termed as Sudden commencement/Sudden impulse (SC/SI). Apart from IP shock speed and solar wind dynamic pressure, IP shock orientation angle also plays a major role in deciding the SC rise time. In the present study, the IP shock orientation angle and SC/SI rise time for 179 IP shocks are estimated which occurred during solar cycle 23. More than 50% of the Shock orientations are in the range of 140°-160°. The SC/SI rise time decreases with the increase in the orientation angle and IP shock speed. In this work, the type of IP shocks i.e., Radio loud (RL) and Radio quiet (RQ) are examined in connection with SC/SI rise time. The RL associated IP shock speeds show a better correlation than RQ shocks with SC/SI rise time irrespective of the orientation angle. Magnetic Cloud (MC) associated shocks dominate in producing less rise time when compared to Ejecta (EJ) shocks. Magneto hydrodynamic (MHD) simulations are used for three different IP shock orientation categories to see the importance of orientation angle in determining the geoeffectiveness. Simulations results reveal that shocks hitting parallel to the magnetosphere are more geoeffective as compared to oblique shocks by means of change in magnetic field, pressure and Field Aligned Current (FAC).

Display format, highlight validity, and highlight method: Their effects on search performance

NASA Technical Reports Server (NTRS)

Donner, Kimberly A.; Mckay, Tim D.; Obrien, Kevin M.; Rudisill, Marianne

1991-01-01

Display format and highlight validity were shown to affect visual display search performance; however, these studies were conducted on small, artificial displays of alphanumeric stimuli. A study manipulating these variables was conducted using realistic, complex Space Shuttle information displays. A 2x2x3 within-subjects analysis of variance found that search times were faster for items in reformatted displays than for current displays. Responses to valid applications of highlight were significantly faster than responses to non or invalidly highlighted applications. The significant format by highlight validity interaction showed that there was little difference in response time to both current and reformatted displays when the highlight validity was applied; however, under the non or invalid highlight conditions, search times were faster with reformatted displays. A separate within-subject analysis of variance of display format, highlight validity, and several highlight methods did not reveal a main effect of highlight method. In addition, observed display search times were compared to search time predicted by Tullis' Display Analysis Program. Benefits of highlighting and reformatting displays to enhance search and the necessity to consider highlight validity and format characteristics in tandem for predicting search performance are discussed.

On the nature of the extremely fast optical rebrightening of the afterglow of GRB 081029

NASA Astrophysics Data System (ADS)

Nardini, M.; Greiner, J.; Krühler, T.; Filgas, R.; Klose, S.; Afonso, P.; Clemens, C.; Guelbenzu, A. N.; Olivares E., F.; Rau, A.; Rossi, A.; Updike, A.; Küpcü Yoldaş, A.; Yoldaş, A.; Burlon, D.; Elliott, J.; Kann, D. A.

2011-07-01

Context. After the launch of the Swift satellite, the gamma-ray burst (GRB) optical light-curve smoothness paradigm has been questioned thanks to the faster and better sampled optical follow-up, which has unveiled a very complex behaviour. This complexity is triggering the interest of the whole GRB community. The GROND multi-channel imager is used to study optical and near-infrared (NIR) afterglows of GRBs with unprecedented optical and near-infrared temporal and spectral resolution. The GRB 081029 has a very prominent optical rebrightening event and is an outstanding example of the application of the multi-channel imager to GRB afterglows. Aims: Here we exploit the rich GROND multi-colour follow-up of GRB 081029 combined with XRT observations to study the nature of late-time rebrightenings that appear in the optical-NIR light-curves of some GRB afterglows. Methods: We analyse the optical and NIR observations obtained with the seven-channel Gamma-Ray burst Optical and Near-infrared Detector (GROND) at the 2.2 m MPI/ESO telescope and the X-ray data obtained with the XRT telescope on board the Swift observatory. The multi-wavelength temporal and spectral evolution is discussed in the framework of different physical models. Results: The extremely steep optical and NIR rebrightening observed in GRB 081029 cannot be explained in the framework of the standard forward shock afterglow model. The absence of a contemporaneous X-ray rebrightening and the evidence of a strong spectral evolution in the optical-NIR bands during the rise suggest two separate components that dominate in the early and late-time light-curves, respectively. The steepness of the optical rise cannot be explained even in the framework of the alternative scenarios proposed in the literature unless a late-time activity of the central engine is assumed. Full GROND photometry of GRB 081029 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A39

Who sleeps best? Longitudinal patterns and covariates of change in sleep quantity, quality, and timing across four university years.

PubMed

Galambos, Nancy L; Vargas Lascano, Dayuma I; Howard, Andrea L; Maggs, Jennifer L

2013-01-01

This study tracked change over time in sleep quantity, disturbance, and timing, and sleep's covariations with living situation, stress, social support, alcohol use, and grade point average (GPA) across four years of university in 186 Canadian students. Women slept longer as they moved through university, and men slept less; rise times were later each year. Students reported sleeping fewer hours, more sleep disturbances, and later rise times during years with higher stress. In years when students lived away from home, they reported more sleep disturbances, later bedtimes, and later rise times. Living on campus was associated with later bedtimes and rise times. Alcohol use was higher and GPA was lower when bedtimes were later. The implications of these observed patterns for understanding the correlates and consequences of university students' sleep are discussed.

Subpicosecond luminescence rise time in magnesium codoped GAGG:Ce scintillator

NASA Astrophysics Data System (ADS)

Tamulaitis, G.; Vaitkevičius, A.; Nargelas, S.; Augulis, R.; Gulbinas, V.; Bohacek, P.; Nikl, M.; Borisevich, A.; Fedorov, A.; Korjik, M.; Auffray, E.

2017-10-01

The influence of co-doping of Gd3Al2GA3O12:Ce (GAGG:Ce) scintillator with magnesium on the rise time of luminescence response was studied in two GAGG:Ce crystals grown in nominally identical conditions except of Mg co-doping in one of them. Time-resolved photoluminescence spectroscopy and free carrier absorption techniques were exploited. It is evidenced that the Mg co-doping decreases the rise time down to sub-picosecond domain. Meanwhile, the light yield decreases by ∼20%. Thus, the feasibility of exploitation of the fast rise edge in luminescence response for ultrafast timing in scintillation detectors is demonstrated. The role of Mg impurities in facilitating the excitation transfer to radiative recombination centers is discussed.

Cellulose nanomaterials as additives for cementitious materials

Treesearch

Tengfei Fu; Robert J. Moon; Pablo Zavatierri; Jeffrey Youngblood; William Jason Weiss

2017-01-01

Cementitious materials cover a very broad area of industries/products (buildings, streets and highways, water and waste management, and many others; see Fig. 20.1). Annual production of cements is on the order of 4 billion metric tons [2]. In general these industries want stronger, cheaper, more durable concrete, with faster setting times, faster rates of strength gain...

Sex difference in Double Iron ultra-triathlon performance

PubMed Central

2013-01-01

Background The present study examined the sex difference in swimming (7.8 km), cycling (360 km), running (84 km), and overall race times for Double Iron ultra-triathletes. Methods Sex differences in split times and overall race times of 1,591 men and 155 women finishing a Double Iron ultra-triathlon between 1985 and 2012 were analyzed. Results The annual number of finishes increased linearly for women and exponentially for men. Men achieved race times of 1,716 ± 243 min compared to 1,834 ± 261 min for women and were 118 ± 18 min (6.9%) faster (p < 0.01). Men finished swimming within 156 ± 63 min compared to women with 163 ± 31 min and were 8 ± 32 min (5.1 ± 5.0%) faster (p < 0.01). For cycling, men (852 ± 196 min) were 71 ± 70 min (8.3 ± 3.5%) faster than women (923 ± 126 min) (p < 0.01). Men completed the run split within 710 ± 145 min compared to 739 ± 150 min for women and were 30 ± 5 min (4.2 ± 3.4%) faster (p = 0.03). The annual three fastest men improved race time from 1,650 ± 114 min in 1985 to 1,339 ± 33 min in 2012 (p < 0.01). Overall race time for women remained unchanged at 1,593 ± 173 min with an unchanged sex difference of 27.1 ± 8.6%. In swimming, the split times for the annual three fastest women (148 ± 14 min) and men (127 ± 20 min) remained unchanged with an unchanged sex difference of 26.8 ± 13.5%. In cycling, the annual three fastest men improved the split time from 826 ± 60 min to 666 ± 18 min (p = 0.02). For women, the split time in cycling remained unchanged at 844 ± 54 min with an unchanged sex difference of 25.2 ± 7.3%. In running, the annual fastest three men improved split times from 649 ± 77 min to 532 ± 16 min (p < 0.01). For women, however, the split times remained unchanged at 657 ± 70 min with a stable sex difference of 32.4 ± 12.5%. Conclusions To summarize, the present findings showed that men were faster than women in Double Iron ultra-triathlon, men improved overall race times, cycling and running split times, and the sex difference remained unchanged across years for overall race time and split times. The sex differences for overall race times and split times were higher than reported for Ironman triathlon. PMID:23849631

Evidence for Harmonic Content and Frequency Evolution of Oscillations During the Rising Phase of X-ray Bursts From 4U 1636-536

NASA Technical Reports Server (NTRS)

Bgattacharyya, Sudip; Strohmayer, E.

2005-01-01

We report on a study of the evolution of burst oscillation properties during the rising phase of X-ray bursts from 4U 1636-536 observed with the proportional counter array (PCA) on board the Rossi X-Ray Timing Explorer (RXTE) . We present evidence for significant harmonic structure of burst oscillation pulses during the early rising phases of bursts. This is the first such detection in burst rise oscillations, and is very important for constraining neutron star structure parameters and the equation of state models of matter at the core of a neutron star. The detection of harmonic content only during the initial portions of the burst rise is consistent with the theoretical expectation that with time the thermonuclear burning region becomes larger, and hence the fundamental and harmonic amplitudes both diminish. We also find, for the first time from this source, strong evidence of oscillation frequency increase during the burst rise. The timing behavior of harmonic content, amplitude, and frequency of burst rise oscillations may be important in understanding the spreading of thermonuclear flames under the extreme physical conditions on neutron star surfaces.

Effect of portal access system and surgery type on surgery times during laparoscopic ovariectomy and salpingectomy in captive African lions and cheetahs.

PubMed

Hartman, Marthinus Jacobus; Monnet, Eric; Kirberger, Robert Murco; Schoeman, Johan Petrus

2016-03-02

A prospective randomized study was used to compare surgery times for laparoscopic ovariectomy and salpingectomy in female African lion (Panthera leo) (n = 14) and cheetah (Acinonyx jubatus) (n = 20) and to compare the use of a multiple portal access system (MPAS) and single portal access system (SPAS) between groups. Two different portal techniques were used, namely MPAS (three separate ports) in lions and SPAS (SILS™ port) in cheetahs, using standard straight laparoscopic instruments. Portal access system and first ovary was not randomized. Five different surgery times were compared for the two different procedures as well as evaluating the use and application of MPAS and SPAS. Carbon dioxide volumes for lions were recorded. In adult lionesses operative time (OPT) (P = 0.016) and total surgical time (TST) (P = 0.032) were significantly shorter for salpingectomy compared to ovariectomy. Similarly in cheetahs OPT (P = 0.001) and TST (P = 0.005) were also shorter for salpingectomy compared to ovariectomy. In contrast, in lion cubs no difference was found in surgery times for ovariectomy and salpingectomy. Total unilateral procedure time was shorter than the respective bilateral time for both procedures (P = 0.019 and P = 0.001) respectively and unilateral salpingectomy was also faster than unilateral ovariectomy (P = 0.035) in cheetahs. Port placement time, suturing time and TST were significantly shorter for SPAS compared to MPAS (P = 0.008). There was, however, no difference in OPT between SPAS and MPAS. Instrument cluttering with SPAS was found to be negligible. There was no difference in mean volume CO2 required to complete ovariectomy in lions but the correlation between bodyweight and total volume of CO2 in lions was significant (rs = 0.867; P = 0.002). Laparoscopic salpingectomy was faster than ovariectomy in both adult lions and cheetahs. Using SPAS, both unilateral procedures were faster than bilateral procedures in cheetahs. Placement and suturing of SPAS in cheetahs was easier and faster compared to three separate ports in lions and lion cubs. The use of standard straight instruments during SPAS did not prolong surgery. Surgery was faster in cubs and CO2 required for laparoscopic sterilization in lions could be determined. Predictable surgery times and CO2 volumes will facilitate the accurate planning and execution of surgery in lions and cheetahs.

Optimal space communications techniques. [discussion of video signals and delta modulation

NASA Technical Reports Server (NTRS)

Schilling, D. L.

1974-01-01

The encoding of video signals using the Song Adaptive Delta Modulator (Song ADM) is discussed. The video signals are characterized as a sequence of pulses having arbitrary height and width. Although the ADM is suited to tracking signals having fast rise times, it was found that the DM algorithm (which permits an exponential rise for estimating an input step) results in a large overshoot and an underdamped response to the step. An overshoot suppression algorithm which significantly reduces the ringing while not affecting the rise time is presented along with formuli for the rise time and the settling time. Channel errors and their effect on the DM encoded bit stream were investigated.

Minimum cost to control bovine tuberculosis in cow-calf herds

PubMed Central

Smith, Rebecca L.; Tauer, Loren W.; Sanderson, Michael W.; Grohn, Yrjo T.

2014-01-01

Bovine tuberculosis (bTB) outbreaks in US cattle herds, while rare, are expensive to control. A stochastic model for bTB control in US cattle herds was adapted to more accurately represent cow-calf herd dynamics and was validated by comparison to 2 reported outbreaks. Control cost calculations were added to the model, which was then optimized to minimize costs for either the farm or the government. The results of the optimization showed that test-and-removal costs were minimized for both farms and the government if only 2 negative whole-herd tests were required to declare a herd free of infection, with a 2–3 month testing interval. However, the optimal testing interval for governments was increased to 2–4 months if the model was constrained to reject control programs leading to an infected herd being declared free of infection. Although farms always preferred test-and-removal to depopulation from a cost standpoint, government costs were lower with depopulation more than half the time in 2 of 8 regions. Global sensitivity analysis showed that indemnity costs were significantly associated with a rise in the cost to the government, and that low replacement rates were responsible for the long time to detection predicted by the model, but that improving the sensitivity of slaughterhouse screening and the probability that a slaughtered animal’s herd of origin can be identified would result in faster detection times. PMID:24703601

High frequency solar influence revealed in sclerosponge-derived Caribbean SST record

NASA Astrophysics Data System (ADS)

Estrella, J.; Winter, A.; Sherman, C.; Mangini, A.

2012-12-01

We present a high-resolution (annual) record of the Caribbean mixed layer temperature at different depths derived from oxygen isotopic ratios obtained from the sclerosponge Ceratoporella nicholsoni. Sclerosponges precipitate their calcium carbonate skeleton in equilibrium with their surrounding environment and are capable of living at depths down to 200 m. The sponges for this project were collected off the coasts of Puerto Rico and the US Virgin Islands in northeastern Caribbean Sea. The records obtained extend from the early 1500's to the present and suggest that the Northeastern Caribbean was 1 - 2 °C cooler during the Little Ice Age than present conditions and that sea surface temperature (SST) has been rising at an average linear rate of 0.009 °C yr-1 since the mid 1800's, three times faster than the World Ocean. Wavelet time series analysis of our records suggests that Caribbean SST variability is regulated by the sunspot cycle, especially when the total solar irradiance is high, at what time the SSTs and the sunspot cycle are highly coupled. Our findings suggest a SST response to solar influence of 0.40 °C (W/m2)-1, almost twice that of the World Ocean. Deceleration of the Caribbean Current is proposed as a possible reason for this disparity. Further work is currently being done on other sponges and other calcium carbonate proxies to examine the extension of this forcing in other climate phenomena.

Minimum cost to control bovine tuberculosis in cow-calf herds.

PubMed

Smith, Rebecca L; Tauer, Loren W; Sanderson, Michael W; Gröhn, Yrjo T

2014-07-01

Bovine tuberculosis (bTB) outbreaks in US cattle herds, while rare, are expensive to control. A stochastic model for bTB control in US cattle herds was adapted to more accurately represent cow-calf herd dynamics and was validated by comparison to 2 reported outbreaks. Control cost calculations were added to the model, which was then optimized to minimize costs for either the farm or the government. The results of the optimization showed that test-and-removal costs were minimized for both farms and the government if only 2 negative whole-herd tests were required to declare a herd free of infection, with a 2-3 month testing interval. However, the optimal testing interval for governments was increased to 2-4 months if the model was constrained to reject control programs leading to an infected herd being declared free of infection. Although farms always preferred test-and-removal to depopulation from a cost standpoint, government costs were lower with depopulation more than half the time in 2 of 8 regions. Global sensitivity analysis showed that indemnity costs were significantly associated with a rise in the cost to the government, and that low replacement rates were responsible for the long time to detection predicted by the model, but that improving the sensitivity of slaughterhouse screening and the probability that a slaughtered animal's herd of origin can be identified would result in faster detection times. Copyright © 2014 Elsevier B.V. All rights reserved.

Temporal Response of Dilute Nitride Multi-Quantum-Well Vertical Cavity Enhanced Photodetector

NASA Astrophysics Data System (ADS)

Nordin, M. S.; Sarcan, F.; Gunes, M.; Boland-Thoms, A.; Erol, A.; Vickers, A. J.

2018-01-01

The temporal response characteristics of a GaInNAs-based vertical resonant cavity enhanced photodetector device are presented for operation at λ ≈ 1.3 μm. The absorption layers of the device are composed of nine 7-nm-thick Ga0.65In0.35N0.02As0.98 quantum wells and are sandwiched between top and bottom AlGaAs/GaAs distributed Bragg reflectors (DBRs). The temperature dependence of the transient photoconductivity (TPC) under different light intensities and bias voltages is reported. Photoluminescence measurements were also performed on structures with and without the top DBR to determine their optical response under continuous illumination. The response time was measured using excitation from a 1047-nm pulsed neodymium-doped yttrium lithium fluoride laser with pulse width of 500 ps and repetition rate of 1 kHz. The rise time of the TPC was 2.27 ns at T = 50 K, decreasing to 1.79 ns at T = 300 K. The TPC decay time was 25.44 ns at T = 50 K, decreasing to 16.58 ns at T = 300 K. With detectivity of 2.28 × 10^{10} {cm}√ {Hz} / {W} and noise-equivalent power of 2.45 × 10^{ - 11} {W/}√ {Hz} , the proposed device is faster and more sensitive with better signal-to-noise ratio compared with other GaInNAs-based resonant cavity enhanced photodetectors (RCEPDs) for operation at 1.3 μm.

Time Dependent Frictional Changes in Ice due to Contact Area Changes

NASA Astrophysics Data System (ADS)

Sevostianov, V.; Lipovsky, B. P.; Rubinstein, S.; Dillavou, S.

2017-12-01

Sliding processes along the ice-bed interface of Earth's great ice sheets are the largest contributor to our uncertainty in future sea level rise. Laboratory experiments that have probed sliding processes have ubiquitously shown that ice-rock interfaces strengthen while in stationary contact (Schulson and Fortt, 2013; Zoet et al., 2013; McCarthy et al., 2017). This so-called frictional ageing effect may have profound consequences for ice sheet dynamics because it introduces the possibility of basal strength hysteresis. Furthermore this effect is quite strong in ice-rock interfaces (more than an order of magnitude more pronounced than in rock-rock sliding) and can double in frictional strength in a matter of minutes, much faster than most frictional aging (Dieterich, 1972; Baumberger and Caroli, 2006). Despite this importance, the underling physics of frictional ageing of ice remain poorly understood. Here we conduct laboratory experiments to image the microscopic points of contact along an ice-glass interface. We optically measure changes in the real area of contact over time using measurements of this reflected optical light intensity. We show that contact area increases with time of stationary contact. This result suggests that thermally enhanced creep of microscopic icy contacts is responsible for the much larger frictional ageing observed in ice-rock versus rock-rock interfaces. Furthermore, this supports a more physically detailed description of the thermal dependence of basal sliding than that used in the current generation of large scale ice sheet models.

Hα Equivalent Widths from the 3D-HST survey: evolution with redshift and dependence on stellar mass†

NASA Astrophysics Data System (ADS)

Fumagalli, Mattia; Patel, Shannon G.; Franx, Marijn; Brammer, Gabriel; van Dokkum, Pieter; da Cunha, Elisabete; Kriek, Mariska; Lundgren, Britt; Momcheva, Ivelina; Rix, Hans-Walter; Schmidt, Kasper B.; Skelton, Rosalind E.; Whitaker, Katherine E.; Labbe, Ivo; Nelson, Erica

2013-07-01

We investigate the evolution of the Hα equivalent width, EW(Hα), with redshift and its dependence on stellar mass, using the first data from the 3D-HST survey, a large spectroscopic Treasury program with the HST-WFC3. Combining our Hα measurements of 854 galaxies at 0.8

A LUMINOUS, FAST RISING UV-TRANSIENT DISCOVERED BY ROTSE: A TIDAL DISRUPTION EVENT?

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

Vinkó, J.; Wheeler, J. C.; Chatzopoulos, E.

2015-01-01

We present follow-up observations of an optical transient (OT) discovered by ROTSE on 2009 January 21. Photometric monitoring was carried out with ROTSE-IIIb in the optical and Swift in the UV up to +70 days after discovery. The light curve showed a fast rise time of ∼10 days followed by a steep decline over the next 60 days, which was much faster than that implied by {sup 56}Ni—{sup 56}Co radioactive decay. The Sloan Digital Sky Survey Data Release 10 database contains a faint, red object at the position of the OT, which appears slightly extended. This and other lines ofmore » evidence suggest that the OT is of extragalactic origin, and this faint object is likely the host galaxy. A sequence of optical spectra obtained with the 9.2 m Hobby-Eberly Telescope between +8 and +45 days after discovery revealed a hot, blue continuum with no visible spectral features. A few weak features that appeared after +30 days probably originated from the underlying host. Fitting synthetic templates to the observed spectrum of the host galaxy revealed a redshift of z = 0.19. At this redshift, the peak magnitude of the OT is close to –22.5, similar to the brightest super-luminous supernovae; however, the lack of identifiable spectral features makes the massive stellar death hypothesis less likely. A more plausible explanation appears to be the tidal disruption of a Sun-like star by the central supermassive black hole. We argue that this transient likely belongs to a class of super-Eddington tidal disruption events.« less

Withholding a Reward-driven Action: Studies of the Rise and Fall of Motor Activation and the Effect of Cognitive Depletion.

PubMed

Freeman, Scott M; Aron, Adam R

2016-02-01

Controlling an inappropriate response tendency in the face of a reward-predicting stimulus likely depends on the strength of the reward-driven activation, the strength of a putative top-down control process, and their relative timing. We developed a rewarded go/no-go paradigm to investigate such dynamics. Participants made rapid responses (on go trials) to high versus low reward-predicting stimuli and sometimes had to withhold responding (on no-go trials) in the face of the same stimuli. Behaviorally, for high versus low reward stimuli, responses were faster on go trials, and there were more errors of commission on no-go trials. We used single-pulse TMS to map out the corticospinal excitability dynamics, especially on no-go trials where control is needed. For successful no-go trials, there was an early rise in motor activation that was then sharply reduced beneath baseline. This activation-reduction pattern was more pronounced for high- versus low-reward trials and in individuals with greater motivational drive for reward. A follow-on experiment showed that, when participants were fatigued by an effortful task, they made more errors on no-go trials for high versus low reward stimuli. Together, these studies show that, when a response is inappropriate, reward-predicting stimuli induce early motor activation, followed by a top-down effortful control process (which we interpret as response suppression) that depends on the strength of the preceding activation. Our findings provide novel information about the activation-suppression dynamics during control over reward-driven actions, and they illustrate how fatigue or depletion leads to control failures in the face of reward.

Sociological Transition and Breast Cancer in the Arab World: the Experience of Lebanon

PubMed

A Lakkis, Najla; Adib, Salim M; Hamadeh, Ghassan; El Jarrah, Rana; H Osman, Mona

2017-05-01

Background: Breast cancer is the leading cause of cancer death among females in Lebanon. This study aimed at analyzing its epidemiology in the country over time. Methods: Data were extracted from the Lebanese National Cancer Registry (NCR) for the years 2004 through 2010. Age-standardized and age-specific incidence rates for cancers per 100,000 population were calculated. Results: Breast cancer ranked first, accounting for an average of 37.6% of all new female cancer cases in Lebanon during the period of 2004-2010. Breast cancer was found to have been increasing faster than other hormone-related women’s cancers (i.e. of the ovaries and corpus uteri). The breast cancer age-standardized incidence rates (world population) (ASRw) increased steadily from 2004 (71.0) to 2010 (105.9), making the burden comparable to that in developed countries, reflecting the influence of sociological and reproductive patterns transitioning from regional norms to global trends. The age-specific incidence rates for breast cancer rose steeply from around age 35-39 years, to reach a first peak in the age group 45-49 years, and then dropped slightly between 50 and 64 years to rise again thereafter and reach a second peak in the 75+ age group. Five-year age-specific rates among Lebanese women between 35 and 49 years were among the highest observed worldwide in 2008. Conclusion: Breast cancer is continuously on the rise in Lebanon. The findings of this study support the national screening recommendation of starting breast cancer screening at the age of 40 years. It is mandatory to conduct an in-depth analysis of contributing factors and develop consequently a comprehensive National Breast Cancer Control strategy. Creative Commons Attribution License

Sociological Transition and Breast Cancer in the Arab World: the Experience of Lebanon

PubMed Central

Lakkis, Najla A; Adib, Salim M; Hamadeh, Ghassan; Jarrah, Rana El; Osman, Mona H

2017-01-01

Background: Breast cancer is the leading cause of cancer death among females in Lebanon. This study aimed at analyzing its epidemiology in the country over time. Methods: Data were extracted from the Lebanese National Cancer Registry (NCR) for the years 2004 through 2010. Age-standardized and age-specific incidence rates for cancers per 100,000 population were calculated. Results: Breast cancer ranked first, accounting for an average of 37.6% of all new female cancer cases in Lebanon during the period of 2004-2010. Breast cancer was found to have been increasing faster than other hormone-related women’s cancers (i.e. of the ovaries and corpus uteri). The breast cancer age-standardized incidence rates (world population) (ASRw) increased steadily from 2004 (71.0) to 2010 (105.9), making the burden comparable to that in developed countries, reflecting the influence of sociological and reproductive patterns transitioning from regional norms to global trends. The age-specific incidence rates for breast cancer rose steeply from around age 35-39 years, to reach a first peak in the age group 45-49 years, and then dropped slightly between 50 and 64 years to rise again thereafter and reach a second peak in the 75+ age group. Five-year age-specific rates among Lebanese women between 35 and 49 years were among the highest observed worldwide in 2008. Conclusion: Breast cancer is continuously on the rise in Lebanon. The findings of this study support the national screening recommendation of starting breast cancer screening at the age of 40 years. It is mandatory to conduct an in-depth analysis of contributing factors and develop consequently a comprehensive National Breast Cancer Control strategy. PMID:28612586

Direct observation of surface ethyl to ethane interconversion upon C2H4 hydrogenation over Pt/Al2O3 catalyst by time-resolved FT-IR spectroscopy.

PubMed

Wasylenko, Walter; Frei, Heinz

2005-09-08

Time-resolved FT-IR spectra of ethylene hydrogenation over alumina-supported Pt catalyst were recorded at 25 ms resolution in the temperature range of 323-473 K using various H2 concentrations (1 atm total gas pressure). Surface ethyl species (2870 and 1200 cm(-1)) were detected at all temperatures along with the gas-phase ethane product (2954 and 2893 cm(-1)). The CH3CH2Pt growth was instantaneous on the time scale of 25 ms under all experimental conditions. At 323 K, the decay time of surface ethyl (122 +/- 10 ms) coincides with the rise time of ethane (144 +/- 14 ms). This establishes direct kinetic evidence for surface ethyl as the relevant reaction intermediate. Such a direct link between the temporal behavior of an unstable surface intermediate and the final product in a heterogeneous catalytic system has not been demonstrated before. A fraction (25%) of the asymptotic ethane growth at 323 K is prompt, indicating that there are surface ethyl species that react much faster than the majority of the CH3CH2Pt intermediates. The dispersive kinetics is attributed to the varying strength of interaction of the ethyl species with the Pt surface caused by heterogeneity of the surface environment. At 473 K, the majority of ethyl intermediates are hydrogenated prior to the recording of the first time slice (24 ms), and a correspondingly large prompt growth of ethane is observed. The yield and kinetics of the surface ethylidyne are in agreement with the known spectator nature of this species.

Inflammatory bowel disease is presenting sooner after immigration in more recent US immigrants from Cuba.

PubMed

Damas, O M; Avalos, D J; Palacio, A M; Gomez, L; Quintero, M A; Deshpande, A R; Sussman, D A; McCauley, J L; Lopez, J; Schwartz, S J; Abreu, M T

2017-08-01

Despite a rising incidence of inflammatory bowel disease (IBD) in Hispanics in the United States, there are no studies examining the relationship between immigrant generation and IBD onset among Hispanics. To determine whether age of IBD diagnosis, time from immigration to IBD diagnosis and IBD phenotype, differed across immigration periods in South Florida Cuban immigrants. This was a cohort of consecutively identified Cuban-born adults who developed IBD in the United States and were followed in gastroenterology (GI) clinic. We divided time cohorts of immigration by historical relevance: before 1980, 1980-1994 and 1995-to-present. We examined differences across time cohorts in diagnosis age, time from immigration to IBD diagnosis, and IBD phenotype (ie, IBD type, disease location). A total of 130 Cuban patients with IBD were included. Age of IBD diagnosis was older in Cubans arriving before 1980 than in those arriving between 1980-1994 or after 1995 (44.7 vs 33.79 and 33.71, respectively, P<.0001). Time between immigration and diagnosis was shorter in patients arriving to the US after 1980 (31.77 years, Standard deviation (SD) 12.83 (<1980) vs 17.13 years, SD 8.55 (1980-1994) and 8.30 years, SD 4.72 (1995-to-present). IBD phenotype, including type of IBD, disease location and surgeries, did not differ significantly across time cohorts. Our study describes changing patterns of IBD onset following immigration in Cubans, suggesting that environmental changes either in the United States, Cuba or both are resulting in faster IBD onset in younger immigrant generations. These studies can inform the search for environmental triggers that may result in IBD. © 2017 John Wiley & Sons Ltd.

MINIFILAMENT ERUPTIONS THAT DRIVE CORONAL JETS IN A SOLAR ACTIVE REGION

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

Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.

We present observations of eruptive events in an active region adjacent to an on-disk coronal hole on 2012 June 30, primarily using data from the Solar Dynamics Observatory ( SDO )/Atmospheric Imaging Assembly (AIA), SDO /Helioseismic and Magnetic Imager (HMI), and STEREO - B . One eruption is of a large-scale (∼100″) filament that is typical of other eruptions, showing slow-rise onset followed by a faster-rise motion starting as flare emissions begin. It also shows an “EUV crinkle” emission pattern, resulting from magnetic reconnections between the exploding filament-carrying field and surrounding field. Many EUV jets, some of which are surges,more » sprays and/or X-ray jets, also occur in localized areas of the active region. We examine in detail two relatively energetic ones, accompanied by GOES M1 and C1 flares, and a weaker one without a GOES signature. All three jets resulted from small-scale (∼20″) filament eruptions consistent with a slow rise followed by a fast rise occurring with flare-like jet-bright-point brightenings. The two more-energetic jets showed crinkle patters, but the third jet did not, perhaps due to its weakness. Thus all three jets were consistent with formation via erupting minifilaments, analogous to large-scale filament eruptions and to X-ray jets in polar coronal holes. Several other energetic jets occurred in a nearby portion of the active region; while their behavior was also consistent with their source being minifilament eruptions, we could not confirm this because their onsets were hidden from our view. Magnetic flux cancelation and emergence are candidates for having triggered the minifilament eruptions.« less

Pyroclastic deposits of the Mount Edgecumbe volcanic field, southeast Alaska: eruptions of a stratified magma chamber

USGS Publications Warehouse

Riehle, J.R.; Champion, D.E.; Brew, D.A.; Lanphere, M.A.

1992-01-01

The Mount Edgecumbe volcanic field in southeastern Alaska consists of 5-6 km3 (DRE) of postglacial pyroclasts that overlie Pleistocene lavas. All eleven pyroclast vents align with the long axis of the field, implying that the pyroclast magma conduits followed a crustal fissure. Most of these vents had previously erupted lavas that are compositionally similar to the pyroclasts, so a persistent magma system (chamber) had likely evolved by the onset of the pyroclastic eruptions. The pyroclastic sequence was deposited in about a millennium and is remarkable for a wide range of upward-increasing silica contents (51-72% SiO2), which is consistent with rise of coexisting magmas at different rates governed by their viscosity. Basaltic and andesitic lava flows have erupted throughout the lifetime of the field. Rhyolite erupted late; we infer that it formed early but was hindered from rising by its high viscosity. Most of the magmas-and all siliceous ones-erupted from vents on the central fissure. Basalt has not erupted from the center of the field during at least the latter part of its lifetime. Thus the field may illustrate basalt underplating: heat and mass flux are concentrated at the center of a stratified magma chamber in which a cap of siliceous melt blocks the rise of basalt. Major-element, strontium isotope, and mineral compositions of unaltered pyroclasts are broadly similar to those of older lavas of similar SiO2 content. Slightly fewer phenocrysts, inherited grains, and trace amphibole in pyroclastic magmas may be due simply to faster rise and less undercooling and degassing before eruption relative to the lavas. Dacite occurs only in the youngest deposits; the magma formed by mixing of andesitic and rhyolitic magmas erupted shortly before by the dacitic vents. ?? 1992.

Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

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

Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

2009-09-27

To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoommore » activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.« less

Switching Characteristics of Ferroelectric Transistor Inverters

NASA Technical Reports Server (NTRS)

Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

2010-01-01

This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

Propagation of solutes and pressure into aquifers following river stage rise

NASA Astrophysics Data System (ADS)

Welch, Chani; Cook, Peter G.; Harrington, Glenn A.; Robinson, Neville I.

2013-09-01

Water level rises associated with river flow events induce both pressure and solute movement into adjacent aquifers at vastly different rates. We present a simple analytical solution that relates the travel time and travel distance of solutes into an aquifer following river stage rise to aquifer properties. Combination with an existing solution for pressure propagation indicates that the ratio of solute to pressure travel times is proportional to the ratio of the volume of water stored in the aquifer before the river stage rise and the volume added by the stage rise and is independent of hydraulic conductivity. Two-dimensional numerical simulations of an aquifer slice perpendicular to a river demonstrate that the solutions are broadly applicable to variably saturated aquifers and partially penetrating rivers. The solutions remain applicable where river stage rise and fall occur, provided that regional hydraulic gradients are low and the duration of the river stage rise is less than pressure and solute travel times to the observation point in the aquifer. Consequently, the solutions provide new insight into the relationships between aquifer properties and distance and time of solute propagation and, in some cases, may be used to estimate system characteristics. Travel time metrics obtained for a flood event in the Cockburn River in eastern Australia using electrical conductivity measurements enabled estimates of aquifer properties and a lateral extent of river-aquifer mixing of 25 m. A detailed time series of any soluble tracer with distinctly different concentrations in river water and groundwater may be used.

Circadian type and bed-timing regularity in 654 retired seniors: correlations with subjective sleep measures.

PubMed

Monk, Timothy H; Buysse, Daniel J; Billy, Bart D; Fletcher, Mary E; Kennedy, Kathy S; Schlarb, Janet E; Beach, Scott R

2011-02-01

Using telephone interview data from retired seniors to explore how inter-individual differences in circadian type (morningness) and bed-timing regularity might be related to subjective sleep quality and quantity. MANCOVA with binary measures of morningness, stability of bedtimes, and stability of rise-times as independent variables; sleep measures as dependent variables; age, former shift work, and gender as covariates. Telephone interviews using a pseudo-random age-targeted sampling process. 654 retired seniors (65 y+, 363M, 291F). none. (1) circadian type (from Composite Scale of Morningness [CSM]), and stability of (2) bedtime and (3) rise-time from the Sleep Timing Questionnaire (STQ). Pittsburgh Sleep Quality Index (PSQI) score, time in bed, time spent asleep, and sleep efficiency, from Sleep Timing Questionnaire (STQ). Morning-type orientation, stability in bedtimes, and stability in rise-times were all associated with better sleep quality (P < 0.001, for all; effect sizes: 0.43, 0.33, and 0.27). Morningness was associated with shorter time in bed (P < 0.0001, effect size 0.45) and time spent asleep (P < 0.005, effect size 0.26). For bedtime and rise-time stability the direction of effect was similar but mostly weaker. In retired seniors, a morning-type orientation and regularity in bedtimes and rise-times appear to be correlated with improved subjective sleep quality and with less time spent in bed.

Faster Array Training and Rapid Analysis for a Sensor Array Intended for an Event Monitor in Air

NASA Technical Reports Server (NTRS)

Homer, Margie L.; Shevade, A. V.; Fonollosa, J.; Huerta, R.

2013-01-01

Environmental monitoring, in particular, air monitoring, is a critical need for human space flight. Both monitoring and life support systems have needs for closed loop process feedback and quality control for environmental factors. Monitoring protects the air environment and water supply for the astronaut crew and different sensors help ensure that the habitat falls within acceptable limits, and that the life support system is functioning properly and efficiently. The longer the flight duration and the farther the destination, the more critical it becomes to have carefully monitored and automated control systems for life support. There is an acknowledged need for an event monitor which samples the air continuously and provides near real-time information on changes in the air. Past experiments with the JPL ENose have demonstrated a lifetime of the sensor array, with the software, of around 18 months. We are working on a sensor array and new algorithms that will incorporate transient sensor responses in the analysis. Preliminary work has already showed more rapid quantification and identification of analytes and the potential for faster training time of the array. We will look at some of the factors that contribute to demonstrating faster training time for the array. Faster training will decrease the integrated sensor exposure to training analytes, which will also help extend sensor lifetime.

Rise Time of the Simulated VERITAS 12 m Davies-Cotton Reflector

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

White, Richard J.

The Very Energetic Radiation Imaging Telescope Array System (VERITAS) will utilise Imaging Atmospheric Cherenkov Telescopes (IACTs) based on a Davies-Cotton design with f-number f/1.0 to detect cosmic gamma-rays. Unlike a parabolic reflector, light from the Davies-Cotton does not arrive isochronously at the camera. Here the effect of the telescope geometry on signal rise-time is examined. An almost square-pulse arrival time profile with a rise time of 1.7 ns is found analytically and confirmed through simulation.

Motivational salience signal in the basal forebrain is coupled with faster and more precise decision speed.

PubMed

Avila, Irene; Lin, Shih-Chieh

2014-03-01

The survival of animals depends critically on prioritizing responses to motivationally salient stimuli. While it is generally believed that motivational salience increases decision speed, the quantitative relationship between motivational salience and decision speed, measured by reaction time (RT), remains unclear. Here we show that the neural correlate of motivational salience in the basal forebrain (BF), defined independently of RT, is coupled with faster and also more precise decision speed. In rats performing a reward-biased simple RT task, motivational salience was encoded by BF bursting response that occurred before RT. We found that faster RTs were tightly coupled with stronger BF motivational salience signals. Furthermore, the fraction of RT variability reflecting the contribution of intrinsic noise in the decision-making process was actively suppressed in faster RT distributions with stronger BF motivational salience signals. Artificially augmenting the BF motivational salience signal via electrical stimulation led to faster and more precise RTs and supports a causal relationship. Together, these results not only describe for the first time, to our knowledge, the quantitative relationship between motivational salience and faster decision speed, they also reveal the quantitative coupling relationship between motivational salience and more precise RT. Our results further establish the existence of an early and previously unrecognized step in the decision-making process that determines both the RT speed and variability of the entire decision-making process and suggest that this novel decision step is dictated largely by the BF motivational salience signal. Finally, our study raises the hypothesis that the dysregulation of decision speed in conditions such as depression, schizophrenia, and cognitive aging may result from the functional impairment of the motivational salience signal encoded by the poorly understood noncholinergic BF neurons.

Motivational Salience Signal in the Basal Forebrain Is Coupled with Faster and More Precise Decision Speed

PubMed Central

Avila, Irene; Lin, Shih-Chieh

2014-01-01

The survival of animals depends critically on prioritizing responses to motivationally salient stimuli. While it is generally believed that motivational salience increases decision speed, the quantitative relationship between motivational salience and decision speed, measured by reaction time (RT), remains unclear. Here we show that the neural correlate of motivational salience in the basal forebrain (BF), defined independently of RT, is coupled with faster and also more precise decision speed. In rats performing a reward-biased simple RT task, motivational salience was encoded by BF bursting response that occurred before RT. We found that faster RTs were tightly coupled with stronger BF motivational salience signals. Furthermore, the fraction of RT variability reflecting the contribution of intrinsic noise in the decision-making process was actively suppressed in faster RT distributions with stronger BF motivational salience signals. Artificially augmenting the BF motivational salience signal via electrical stimulation led to faster and more precise RTs and supports a causal relationship. Together, these results not only describe for the first time, to our knowledge, the quantitative relationship between motivational salience and faster decision speed, they also reveal the quantitative coupling relationship between motivational salience and more precise RT. Our results further establish the existence of an early and previously unrecognized step in the decision-making process that determines both the RT speed and variability of the entire decision-making process and suggest that this novel decision step is dictated largely by the BF motivational salience signal. Finally, our study raises the hypothesis that the dysregulation of decision speed in conditions such as depression, schizophrenia, and cognitive aging may result from the functional impairment of the motivational salience signal encoded by the poorly understood noncholinergic BF neurons. PMID:24642480

Summary of Sonic Boom Rise Times Observed During FAA Community Response Studies over a 6-Month Period in the Oklahoma City Area

NASA Technical Reports Server (NTRS)

Maglieri, Domenic J.; Sothcott, Victor E.

1990-01-01

The sonic boom signature data acquired from about 1225 supersonic flights, over a 6-month period in 1964 in the Oklahoma City area, was enhanced with the addition of data relating to rise times and total signature duration. These later parameters, not available at the time of publication of the original report on the Oklahoma City sonic boom exposures, are listed in tabular form along with overpressure, positive impulse, positive duration, and waveform category. Airplane operating information along with the surface weather observations are also included. Sonic boom rise times include readings to the 1/2, 3/4, and maximum overpressure values. Rise time relative probabilities for various lateral locations from the ground track of 0, 5, and 10 miles are presented along with the variation of rise times with flight altitude. The tabulated signature data, along with corresponding airplane operating conditions and surface and upper level atmospheric information, are also available on electronic files to provide it in the format for more efficient and effective utilization.

Beyond the faster-is-slower effect

NASA Astrophysics Data System (ADS)

Sticco, I. M.; Cornes, F. E.; Frank, G. A.; Dorso, C. O.

2017-11-01

The "faster-is-slower" effect arises when crowded people push each other to escape through an exit during an emergency situation. As individuals push harder, a statistical slowing down in the evacuation time can be achieved. The slowing down is caused by the presence of small groups of pedestrians (say, a small human cluster) that temporarily block the way out when trying to leave the room. The pressure on the pedestrians belonging to this blocking cluster increases for increasing anxiety levels and/or a larger number of individuals trying to leave the room through the same door. Our investigation shows, however, that very high pressures alter the dynamics in the blocking cluster and, thus, change the statistics of the time delays along the escaping process. A reduction in the long lasting delays can be acknowledged, while the overall evacuation performance improves. We present results on this phenomenon taking place beyond the faster-is-slower regime.

On Murray Jackson's 1961 'Chair, couch and countertransference'.

PubMed

Connolly, Angela

2015-09-01

One of the problems facing psychoanalysts of all schools is that theory has evolved at a much faster pace than practice. Whereas there has been an explosion of theory, practice has remained, at least officially, static and unchanging. It is in this sense that Murray Jackson's 1961 paper is still relevant today. Despite the rise of the new relational and intersubjective paradigms, most psychoanalysts, and not a few Jungian analysts, still seem to feel that the couch is an essential component of the analytical setting and process. If the use of the couch is usually justified by the argument that it favours regression, facilitates analytical reverie and protects the patient from the influence of the analyst, over time many important psychoanalysts have come to challenge this position. Increasingly these analysts suggest that the use of the couch may actually be incompatible with the newer theoretical models. This contention is strengthened by some of the findings coming from the neurosciences and infant research. This underlines the necessity of empirical research to verify the clinical effectiveness of these different positions, couch or face-to-face, but it is exactly this type of research that is lacking. © 2015, The Society of Analytical Psychology.

Computational Characterization of Type I collagen-based Extra-cellular Matrix

NASA Astrophysics Data System (ADS)

Liang, Long; Jones, Christopher Allen Rucksack; Lin, Daniel; Jiao, Yang; Sun, Bo

2015-03-01

A model of extracellular matrix (ECM) of collagen fibers has been built, in which cells could communicate with distant partners via fiber-mediated long-range-transmitted stress states. The ECM is modeled as a spring-like fiber network derived from skeletonized confocal microscopy data. Different local and global perturbations have been performed on the network, each followed by an optimized global Monte-Carlo (MC) energy minimization leading to the deformed network in response to the perturbations. In the optimization, a highly efficient local energy update procedure is employed and force-directed MC moves are used, which results in a convergence to the energy minimum state 20 times faster than the commonly used random displacement trial moves in MC. Further analysis and visualization of the distribution and correlation of the resulting force network reveal that local perturbations can give rise to global impacts: the force chains formed with a linear extent much further than the characteristic length scale associated with the perturbation sites and average fiber length. This behavior provides a strong evidence for our hypothesis of fiber-mediated long-range force transmission in ECM networks and the resulting long-range cell-cell mechanical signaling. ASU Seed Grant.

Characterization of edge turbulence in different states of divertor detachment using reflectometry in the ASDEX Upgrade tokamak

NASA Astrophysics Data System (ADS)

Nikolaeva, V.; Guimarais, L.; Manz, P.; Carralero, D.; Manso, M. E.; Stroth, U.; Silva, C.; Conway, G. D.; Seliunin, E.; Vicente, J.; Brida, D.; Aguiam, D.; Santos, J.; Silva, A.; ASDEX Upgrade team; MST1 team

2018-05-01

Transport in the scrape-off layer (SOL) depends on the state of divertor detachment. L-mode discharges were analyzed where the state of divertor detachment is varied through a density ramp-up. By means of reflectometry measurements at the low (LFS) and the high field side (HFS), midplane density fluctuations are studied for the first time in ASDEX Upgrade simultaneously at both sides of the tokamak. Radial density fluctuation profiles (δ {n}e/{n}e) increase with radius in both the HFS and the LFS. It is found that in the SOL density fluctuations at the LFS have about a factor of two larger amplitude than at the HFS in agreement with ballooned transport. Density fluctuations at the LFS show a modest variation with increasing background density resulting mainly from a rise of low frequency components. Experimental results are in good agreement with an enhanced convection of filaments at the LFS at the beginning of outer divertor detachment leading to a flatter SOL density profile. In this phase of the discharge, density fluctuations measured at the HFS far-SOL display a strong increase, which may be associated with the presence of faster filaments originated at the LFS.

Analysis and Modeling of Intense Oceanic Lightning

NASA Astrophysics Data System (ADS)

Zoghzoghy, F. G.; Cohen, M.; Said, R.; Lehtinen, N. G.; Inan, U.

2014-12-01

Recent studies using lightning data from geo-location networks such as GLD360 suggest that lightning strokes are more intense over the ocean than over land, even though they are less common [Said et al. 2013]. We present an investigation of the physical differences between oceanic and land lightning. We have deployed a sensitive Low Frequency (1 MHz sampling rate) radio receiver system aboard the NOAA Ronald W. Brown research vessel and have collected thousands of lightning waveforms close to deep oceanic lightning. We analyze the captured waveforms, describe our modeling efforts, and summarize our findings. We model the ground wave (gw) portion of the lightning sferics using a numerical method built on top of the Stanford Full Wave Method (FWM) [Lehtinen and Inan 2008]. The gwFWM technique accounts for propagation over a curved Earth with finite conductivity, and is used to simulate an arbitrary current profile along the lightning channel. We conduct a sensitivity analysis and study the current profiles for land and for oceanic lightning. We find that the effect of ground conductivity is minimal, and that stronger oceanic radio intensity does not result from shorter current rise-time or from faster return stroke propagation speed.

Expected load spectra of prototype Francis turbines in low-load operation using numerical simulations and site measurements

NASA Astrophysics Data System (ADS)

Eichhorn, M.; Taruffi, A.; Bauer, C.

2017-04-01

The operators of hydropower plants are forced to extend the existing operating ranges of their hydraulic machines to remain competitive on the energy market due to the rising amount of wind and solar power. Faster response times and a higher flexibility towards part- and low-load conditions enable a better electric grid control and assure therefore an economic operation of the power plant. The occurring disadvantage is a higher dynamic excitation of affected machine components, especially Francis turbine runners, due to pressure pulsations induced by unsteady flow phenomena (e.g. draft tube vortex ropes). Therefore, fatigue analysis becomes more important even in the design phase of the hydraulic machines to evaluate the static and dynamic load in different operating conditions and to reduce maintenance costs. An approach including a one-way coupled fluid-structure interaction has been already developed using unsteady CFD simulations and transient FEM computations. This is now applied on two Francis turbines with different specific speeds and power ranges, to obtain the load spectra of both machines. The results are compared to strain gauge measurements on the according Francis turbines to validate the overall procedure.

Innovative heating of large-size automotive Li-ion cells

NASA Astrophysics Data System (ADS)

Yang, Xiao-Guang; Liu, Teng; Wang, Chao-Yang

2017-02-01

Automotive Li-ion cells are becoming much larger and thicker in order to reduce the cell count and increase battery reliability, posing a new challenge to battery heating from the cold ambient due to poor through-plane heat transfer across a cell's multiple layers of electrodes and separators. In this work, widely used heating methods, including internal heating using the cell's resistance and external heating by resistive heaters, are compared with the recently developed self-heating Li-ion battery (SHLB) with special attention to the heating speed and maximum local temperature critical to battery safety. Both conventional methods are found to be slow due to low heating power required to maintain battery safety. The heating power in the external heating method is limited by the risk of local over-heating, in particular for thick cells. As a result, the external heating method is restricted to ∼20 min slow heating for a 30 °C temperature rise. In contrast, the SHLB is demonstrated to reach a heating speed of 1-2 °C/sec, ∼40 times faster for large-size thick cells, with nearly 100% heating efficiency and spatially uniform heating free from safety concerns.

North Atlantic summers have warmed more than winters since 1353, and the response of marine zooplankton.

PubMed

Kamenos, Nicholas A

2010-12-28

Modeling and measurements show that Atlantic marine temperatures are rising; however, the low temporal resolution of models and restricted spatial resolution of measurements (i) mask regional details critical for determining the rate and extent of climate variability, and (ii) prevent robust determination of climatic impacts on marine ecosystems. To address both issues for the North East Atlantic, a fortnightly resolution marine climate record from 1353-2006 was constructed for shallow inshore waters and compared to changes in marine zooplankton abundance. For the first time summer marine temperatures are shown to have increased nearly twice as much as winter temperatures since 1353. Additional climatic instability began in 1700 characterized by ∼5-65 year climate oscillations that appear to be a recent phenomenon. Enhanced summer-specific warming reduced the abundance of the copepod Calanus finmarchicus, a key food item of cod, and led to significantly lower projected abundances by 2040 than at present. The faster increase of summer marine temperatures has implications for climate projections and affects abundance, and thus biomass, near the base of the marine food web with potentially significant feedback effects for marine food security.

Auditory perceptual simulation: Simulating speech rates or accents?

PubMed

Zhou, Peiyun; Christianson, Kiel

2016-07-01

When readers engage in Auditory Perceptual Simulation (APS) during silent reading, they mentally simulate characteristics of voices attributed to a particular speaker or a character depicted in the text. Previous research found that auditory perceptual simulation of a faster native English speaker during silent reading led to shorter reading times that auditory perceptual simulation of a slower non-native English speaker. Yet, it was uncertain whether this difference was triggered by the different speech rates of the speakers, or by the difficulty of simulating an unfamiliar accent. The current study investigates this question by comparing faster Indian-English speech and slower American-English speech in the auditory perceptual simulation paradigm. Analyses of reading times of individual words and the full sentence reveal that the auditory perceptual simulation effect again modulated reading rate, and auditory perceptual simulation of the faster Indian-English speech led to faster reading rates compared to auditory perceptual simulation of the slower American-English speech. The comparison between this experiment and the data from Zhou and Christianson (2016) demonstrate further that the "speakers'" speech rates, rather than the difficulty of simulating a non-native accent, is the primary mechanism underlying auditory perceptual simulation effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Incidental learning speeds visual search by lowering response thresholds, not by improving efficiency: Evidence from eye movements

PubMed Central

Hout, Michael C.; Goldinger, Stephen D.

2011-01-01

When observers search for a target object, they incidentally learn the identities and locations of “background” objects in the same display. This learning can facilitate search performance, eliciting faster reaction times for repeated displays (Hout & Goldinger, 2010). Despite these findings, visual search has been successfully modeled using architectures that maintain no history of attentional deployments; they are amnesic (e.g., Guided Search Theory; Wolfe, 2007). In the current study, we asked two questions: 1) under what conditions does such incidental learning occur? And 2) what does viewing behavior reveal about the efficiency of attentional deployments over time? In two experiments, we tracked eye movements during repeated visual search, and we tested incidental memory for repeated non-target objects. Across conditions, the consistency of search sets and spatial layouts were manipulated to assess their respective contributions to learning. Using viewing behavior, we contrasted three potential accounts for faster searching with experience. The results indicate that learning does not result in faster object identification or greater search efficiency. Instead, familiar search arrays appear to allow faster resolution of search decisions, whether targets are present or absent. PMID:21574743

Encoding of sound envelope transients in the auditory cortex of juvenile rats and adult rats.

PubMed

Lu, Qi; Jiang, Cuiping; Zhang, Jiping

2016-02-01

Accurate neural processing of time-varying sound amplitude and spectral information is vital for species-specific communication. During postnatal development, cortical processing of sound frequency undergoes progressive refinement; however, it is not clear whether cortical processing of sound envelope transients also undergoes age-related changes. We determined the dependence of neural response strength and first-spike latency on sound rise-fall time across sound levels in the primary auditory cortex (A1) of juvenile (P20-P30) rats and adult (8-10 weeks) rats. A1 neurons were categorized as "all-pass", "short-pass", or "mixed" ("all-pass" at high sound levels to "short-pass" at lower sound levels) based on the normalized response strength vs. rise-fall time functions across sound levels. The proportions of A1 neurons within each of the three categories in juvenile rats were similar to that in adult rats. In general, with increasing rise-fall time, the average response strength decreased and the average first-spike latency increased in A1 neurons of both groups. At a given sound level and rise-fall time, the average normalized neural response strength did not differ significantly between the two age groups. However, the A1 neurons in juvenile rats showed greater absolute response strength, longer first-spike latency compared to those in adult rats. In addition, at a constant sound level, the average first-spike latency of juvenile A1 neurons was more sensitive to changes in rise-fall time. Our results demonstrate the dependence of the responses of rat A1 neurons on sound rise-fall time, and suggest that the response latency exhibit some age-related changes in cortical representation of sound envelope rise time. Copyright © 2015 Elsevier Ltd. All rights reserved.

Switching among graphic patterns is governed by oscillatory coordination dynamics: implications for understanding handwriting

PubMed Central

Zanone, Pier-Giorgio; Athènes, Sylvie

2013-01-01

Revisiting an original idea by Hollerbach (1981), previous work has established that the production of graphic shapes, assumed to be the blueprint for handwriting, is governed by the dynamics of orthogonal non-linear coupled oscillators. Such dynamics determines few stable coordination patterns, giving rise to a limited set of preferred graphic shapes, namely, four lines and four ellipsoids independent of orientation. The present study investigates the rules of switching among such graphic coordination patterns. Seven participants were required to voluntarily switch within twelve pairs of shapes presented on a graphic tablet. In line with previous theoretical and experimental work on bimanual coordination, results corroborated our hypothesis that the relative stability of the produced coordination patterns determines the time needed for switching: the transition to a more stable pattern was shorter, and inversely. Moreover, switching between patterns with the same orientation but different eccentricities was faster than with a change in orientation. Nonetheless, the switching time covaried strictly with the change in relative phase effected by the transition between two shapes, whether this implied a change in eccentricity or in orientation. These findings suggest a new operational definition of what the (motor) units or strokes of handwriting are and shed a novel light on how coarticulation and recruitment of degrees of freedom may occur in graphic skills. They also yield some leads for understanding the acquisition and the neural underpinnings of handwriting. PMID:24069014

iPTF 16asu: A Luminous, Rapidly Evolving, and High-velocity Supernova

DOE PAGES

Whitesides, L.; Lunnan, R.; Kasliwal, M. M.; ...

2017-12-18

Wide-field surveys are discovering a growing number of rare transients whose physical origin is not yet well understood. We present optical and UV data and analysis of intermediate Palomar Transient Factory (iPTF) 16asu, a luminous, rapidly evolving, high-velocity, stripped-envelope supernova (SN). With a rest-frame rise time of just four days and a peak absolute magnitude of M g = -20.4 mag, the light curve of iPTF 16asu is faster and more luminous than that of previous rapid transients. The spectra of iPTF 16asu show a featureless blue continuum near peak that develops into an SN Ic-BL spectrum on the decline.more » We show that while the late-time light curve could plausibly be powered by 56Ni decay, the early emission requires a different energy source. Nondetections in the X-ray and radio strongly constrain the energy coupled to relativistic ejecta to be at most comparable to the class of low-luminosity gamma-ray bursts (GRBs). We suggest that the early emission may have been powered by either a rapidly spinning-down magnetar or by shock breakout in an extended envelope of a very energetic explosion. In either scenario a central engine is required, making iPTF 16asu an intriguing transition object between superluminous SNe, SNe Ic-BL, and low-luminosity GRBs.« less

Continuous extraovular administration of prostaglandin F2alpha for midtrimester abortion.

PubMed

Lauersen, N H; Wilson, K H

1974-09-15

Midtrimester abortion was successfully induced in 74 of 76 patients by a continuous extraovular administration of (PGF2alpha) prostaglandin F2alpha via a constant-infusion pump. 2 patients in the 13th-14th weeks of gestation failed to abort despite good uterine activity. The mean abortion time for successful inductions was 16.21 hours. Parous patients aborted somewhat faster than nulliparous patients, but the difference was not statistically significant. All patients were monitored throughout the abortion procedure, and uterine activity was calculated and analyzed. Uterine activity developed within 15 minutes of PGF2alpha instillation and showed the characteristic uterine response to PGs with a sharp rise in intrauterine tonus. The gastrointestinal side effects in this series were much less than those reported for intraamniotic instillation of PG, and there was good patient tolerance of the procedure. The main complication of extraovular administration of PGF2alpha for midtrimester abortion was endometritis, which occurred in 7 patients. The patients who developed endometritis had, as a group, longer abortion times (mean=28 hours). 3 patients with severe preeclampsia and intrauterine death in the third trimester also had successfully induced labor with extraovular administration of PGF2alpha. The method of PGF2alpha administration in the series was found to have a high success rate, good patient tolerance, and fewer side effects than when abortion was induced by intraamniotic instillation of PGF2alpha.

iPTF 16asu: A Luminous, Rapidly Evolving, and High-velocity Supernova

NASA Astrophysics Data System (ADS)

Whitesides, L.; Lunnan, R.; Kasliwal, M. M.; Perley, D. A.; Corsi, A.; Cenko, S. B.; Blagorodnova, N.; Cao, Y.; Cook, D. O.; Doran, G. B.; Frederiks, D. D.; Fremling, C.; Hurley, K.; Karamehmetoglu, E.; Kulkarni, S. R.; Leloudas, G.; Masci, F.; Nugent, P. E.; Ritter, A.; Rubin, A.; Savchenko, V.; Sollerman, J.; Svinkin, D. S.; Taddia, F.; Vreeswijk, P.; Wozniak, P.

2017-12-01

Wide-field surveys are discovering a growing number of rare transients whose physical origin is not yet well understood. Here we present optical and UV data and analysis of intermediate Palomar Transient Factory (iPTF) 16asu, a luminous, rapidly evolving, high-velocity, stripped-envelope supernova (SN). With a rest-frame rise time of just four days and a peak absolute magnitude of {M}{{g}}=-20.4 mag, the light curve of iPTF 16asu is faster and more luminous than that of previous rapid transients. The spectra of iPTF 16asu show a featureless blue continuum near peak that develops into an SN Ic-BL spectrum on the decline. We show that while the late-time light curve could plausibly be powered by 56Ni decay, the early emission requires a different energy source. Nondetections in the X-ray and radio strongly constrain the energy coupled to relativistic ejecta to be at most comparable to the class of low-luminosity gamma-ray bursts (GRBs). We suggest that the early emission may have been powered by either a rapidly spinning-down magnetar or by shock breakout in an extended envelope of a very energetic explosion. In either scenario a central engine is required, making iPTF 16asu an intriguing transition object between superluminous SNe, SNe Ic-BL, and low-luminosity GRBs.

Sea-level variability in the Common Era along the Atlantic coast of North America

NASA Astrophysics Data System (ADS)

Kemp, A.; Kopp, R. E.; Horton, B.; Little, C. M.; Engelhart, S. E.; Mitrovica, J. X.

2017-12-01

Common Era relative sea-level trends on the margins of the North Atlantic Ocean vary through time and across space as a result of simultaneous global (basin-wide)-, regional- (linear and non-linear), and local-scale processes. A growing suite of relative sea-level reconstructions derived from dated salt-marsh (and mangrove) sediment on the Atlantic coast of North America provides an opportunity to quantify the contributions from several physical processes to Common Era sea-level trends. In particular, this coastline is susceptible to relative sea-level changes caused by melting of the Greenland Ice Sheet and redistribution of existing ocean mass on timescales of days to centuries by evolving patterns and strengths of atmospheric and oceanic circulation. Using a case study from Newfoundland, Canada, we demonstrate how high-resolution (decadal- and decimeter-scale) relative sea level reconstructions are produced from sequences of salt-marsh sediment that were deposited under conditions of long-term sea-level rise. We use an expanded database of Common Era relative sea-level reconstructions from the Atlantic coast of North America that spans locations from Newfoundland to the southern Florida to identify spatial and temporal patterns of change. A spatio-temporal statistical model enables us to decompose each reconstruction (with uncertainty) into contributions from global-, regional- (linear and non-linear), and local-scale processes. This analysis shows that spatially-variable glacio-isostatic adjustment was the primary driver of sea-level change. The global signal is dominated by the onset of anthropogenic sea-level rise in the late 19th century, which caused the 20th century to experience a faster rate of rise than any of the preceding 26 centuries. Differentiating between regional non-linear and local-scale processes is a challenging using an inherently sparse network of reconstructions. However, we show that sites south of Cape Hatteras have sea-level histories distinct to those from more northward locations and propose that this spatial pattern is best explained by dynamic processes that could include century-scale NAO-driven circulation changes. Complementary paleoenvironmental reconstructions from diverse proxies support this interpretation.

Simplest chronoscope. III. Further comparisons between reaction times obtained by meterstick versus machine.

PubMed

Montare, Alberto

2013-06-01

The three classical Donders' reaction time (RT) tasks (simple, choice, and discriminative RTs) were employed to compare reaction time scores from college students obtained by use of Montare's simplest chronoscope (meterstick) methodology to scores obtained by use of a digital-readout multi-choice reaction timer (machine). Five hypotheses were tested. Simple RT, choice RT, and discriminative RT were faster when obtained by meterstick than by machine. The meterstick method showed higher reliability than the machine method and was less variable. The meterstick method of the simplest chronoscope may help to alleviate the longstanding problems of low reliability and high variability of reaction time performances; while at the same time producing faster performance on Donders' simple, choice and discriminative RT tasks than the machine method.

The response of a fast scintillator screen (YAP:Ce) to low energy ions (0-40 keV) and its use to detect fast-ion-loss in stellarator TJ-II

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

Martínez, M., E-mail: marcos.martinez@externos.ciemat.es; Zurro, B.; Baciero, A.

2016-11-15

A systematic study of scintillation materials was undertaken to improve the time resolution of the fast ion diagnostic currently installed at TJ-II stellarator. It was found that YAP:Ce (formula YAlO{sub 3}:Ce, Yttrium Aluminum Perovskite doped with Cerium) ionoluminescence offers better sensitivity and time response compared to the standard detector material, SrGa{sub 2}S{sub 4}:Eu (TG-Green), currently used in TJ-II. A comparison between both materials was carried out by irradiating them with H{sup +} ions of up to 40 keV using a dedicated laboratory setup. It is found that for the low energy ions of interest at TJ-II, YAP:Ce offers 20 timesmore » higher sensitivity than TG-Green and much faster decay time, 27 ns versus 540 ns. It is expected that the use of YAP:Ce in combination with a faster data acquisition and an ion counting software as part of the TJ-II ion luminescent probe will provide 20 times faster data on ion loss.« less

The effects of L-theanine, caffeine and their combination on cognition and mood.

PubMed

Haskell, Crystal F; Kennedy, David O; Milne, Anthea L; Wesnes, Keith A; Scholey, Andrew B

2008-02-01

L-Theanine is an amino acid found naturally in tea. Despite the common consumption of L-theanine, predominantly in combination with caffeine in the form of tea, only one study to date has examined the cognitive effects of this substance alone, and none have examined its effects when combined with caffeine. The present randomised, placebo-controlled, double-blind, balanced crossover study investigated the acute cognitive and mood effects of L-theanine (250 mg), and caffeine (150 mg), in isolation and in combination. Salivary caffeine levels were co-monitored. L-Theanine increased 'headache' ratings and decreased correct serial seven subtractions. Caffeine led to faster digit vigilance reaction time, improved Rapid Visual Information Processing (RVIP) accuracy and attenuated increases in self-reported 'mental fatigue'. In addition to improving RVIP accuracy and 'mental fatigue' ratings, the combination also led to faster simple reaction time, faster numeric working memory reaction time and improved sentence verification accuracy. 'Headache' and 'tired' ratings were reduced and 'alert' ratings increased. There was also a significant positive caffeine x L-theanine interaction on delayed word recognition reaction time. These results suggest that beverages containing L-theanine and caffeine may have a different pharmacological profile to those containing caffeine alone.

The Simplest Chronoscope V: A Theory of Dual Primary and Secondary Reaction Time Systems.

PubMed

Montare, Alberto

2016-12-01

Extending work by Montare, visual simple reaction time, choice reaction time, discriminative reaction time, and overall reaction time scores obtained from college students by the simplest chronoscope (a falling meterstick) method were significantly faster as well as significantly less variable than scores of the same individuals from electromechanical reaction timers (machine method). Results supported the existence of dual reaction time systems: an ancient primary reaction time system theoretically activating the V5 parietal area of the dorsal visual stream that evolved to process significantly faster sensory-motor reactions to sudden stimulations arising from environmental objects in motion, and a secondary reaction time system theoretically activating the V4 temporal area of the ventral visual stream that subsequently evolved to process significantly slower sensory-perceptual-motor reactions to sudden stimulations arising from motionless colored objects. © The Author(s) 2016.

Pacing Behavior and Tactical Positioning in 1500-m Short-Track Speed Skating.

PubMed

Konings, Marco J; Noorbergen, Olaf S; Parry, David; Hettinga, Florentina J

2016-01-01

To gain more insight in pacing behavior and tactical positioning in 1500-m short-track speed skating, a sport in which several athletes directly compete in the same race. Lap times and intermediate rankings of elite 1500-m short-track- skating competitors were collected over the season 2012-13 (N = 510, 85 races). Two statistical approaches were used to assess pacing behavior and tactical positioning. First, lap times were analyzed using a MANOVA, and for each lap differences between sex, race type, final rankings, and stage of competition were determined. Second, Kendall tau b correlations were used to assess relationships between intermediate and final rankings. In addition, intermediate rankings of the winner of each race were examined. In 1500 m (13.5 laps of 111.12 m), correlations between intermediate and final ranking gradually increased throughout the race (eg, lap 1, r = .05; lap 7, r = .26; lap 13, r = .85). Moreover, the percentage of race winners skating in the leading position was over 50% during the last 3 laps. Top finishers were faster than bottom-place finishers only during the last 5 laps, with on average 0.1- to 1.5-s faster lap times of the race winners compared with the others during the last 5 laps. Although a fast start led to faster finishing times, top finishers were faster than bottom-placed finishers only during the last 5 laps. Moreover, tactical positioning at 1 of the foremost positions during the latter phase of the race appeared to be a strong determinant of finishing position.

Faster Smith-Waterman database searches with inter-sequence SIMD parallelisation

PubMed Central

2011-01-01

Background The Smith-Waterman algorithm for local sequence alignment is more sensitive than heuristic methods for database searching, but also more time-consuming. The fastest approach to parallelisation with SIMD technology has previously been described by Farrar in 2007. The aim of this study was to explore whether further speed could be gained by other approaches to parallelisation. Results A faster approach and implementation is described and benchmarked. In the new tool SWIPE, residues from sixteen different database sequences are compared in parallel to one query residue. Using a 375 residue query sequence a speed of 106 billion cell updates per second (GCUPS) was achieved on a dual Intel Xeon X5650 six-core processor system, which is over six times more rapid than software based on Farrar's 'striped' approach. SWIPE was about 2.5 times faster when the programs used only a single thread. For shorter queries, the increase in speed was larger. SWIPE was about twice as fast as BLAST when using the BLOSUM50 score matrix, while BLAST was about twice as fast as SWIPE for the BLOSUM62 matrix. The software is designed for 64 bit Linux on processors with SSSE3. Source code is available from http://dna.uio.no/swipe/ under the GNU Affero General Public License. Conclusions Efficient parallelisation using SIMD on standard hardware makes it possible to run Smith-Waterman database searches more than six times faster than before. The approach described here could significantly widen the potential application of Smith-Waterman searches. Other applications that require optimal local alignment scores could also benefit from improved performance. PMID:21631914

Faster Smith-Waterman database searches with inter-sequence SIMD parallelisation.

PubMed

Rognes, Torbjørn

2011-06-01

The Smith-Waterman algorithm for local sequence alignment is more sensitive than heuristic methods for database searching, but also more time-consuming. The fastest approach to parallelisation with SIMD technology has previously been described by Farrar in 2007. The aim of this study was to explore whether further speed could be gained by other approaches to parallelisation. A faster approach and implementation is described and benchmarked. In the new tool SWIPE, residues from sixteen different database sequences are compared in parallel to one query residue. Using a 375 residue query sequence a speed of 106 billion cell updates per second (GCUPS) was achieved on a dual Intel Xeon X5650 six-core processor system, which is over six times more rapid than software based on Farrar's 'striped' approach. SWIPE was about 2.5 times faster when the programs used only a single thread. For shorter queries, the increase in speed was larger. SWIPE was about twice as fast as BLAST when using the BLOSUM50 score matrix, while BLAST was about twice as fast as SWIPE for the BLOSUM62 matrix. The software is designed for 64 bit Linux on processors with SSSE3. Source code is available from http://dna.uio.no/swipe/ under the GNU Affero General Public License. Efficient parallelisation using SIMD on standard hardware makes it possible to run Smith-Waterman database searches more than six times faster than before. The approach described here could significantly widen the potential application of Smith-Waterman searches. Other applications that require optimal local alignment scores could also benefit from improved performance.

Planning for operating room efficiency and faster anesthesia wake-up time in open major upper abdominal surgery.

PubMed

Lai, Hou-Chuan; Chan, Shun-Ming; Lu, Chueng-He; Wong, Chih-Shung; Cherng, Chen-Hwan; Wu, Zhi-Fu

2017-02-01

Reducing anesthesia-controlled time (ACT) may improve operation room (OR) efficiency result from different anesthetic techniques. However, the information about the difference in ACT between desflurane (DES) anesthesia and propofol-based total intravenous anesthesia (TIVA) techniques for open major upper abdominal surgery under general anesthesia (GA) is not available in the literature.This retrospective study uses our hospital database to analyze the ACT of open major upper abdominal surgery without liver resection after either desflurane/fentanyl-based anesthesia or TIVA via target-controlled infusion with fentanyl/propofol from January 2010 to December 2011. The various time intervals including waiting for anesthesia time, anesthesia time, surgical time, extubation time, exit from OR after extubation, total OR time, and postanesthetic care unit (PACU) stay time and percentage of prolonged extubation (≥15 minutes) were compared between these 2 anesthetic techniques.We included data from 343 patients, with 159 patients receiving TIVA and 184 patients receiving DES. The only significant difference is extubation time, TIVA was faster than the DES group (8.5 ± 3.8 vs 9.4 ± 3.7 minutes; P = 0.04). The factors contributed to prolonged extubation were age, gender, body mass index, DES anesthesia, and anesthesia time.In our hospital, propofol-based TIVA by target-controlled infusion provides faster emergence compared with DES anesthesia; however, it did not improve OR efficiency in open major abdominal surgery. Older, male gender, higher body mass index, DES anesthesia, and lengthy anesthesia time were factors that contribute to extubation time.

Cost-Benefit Analysis of a Support Program for Nursing Staff.

PubMed

Moran, Dane; Wu, Albert W; Connors, Cheryl; Chappidi, Meera R; Sreedhara, Sushama K; Selter, Jessica H; Padula, William V

2017-04-27

A peer-support program called Resilience In Stressful Events (RISE) was designed to help hospital staff cope with stressful patient-related events. The aim of this study was to evaluate the impact of the RISE program by conducting an economic evaluation of its cost benefit. A Markov model with a 1-year time horizon was developed to compare the cost benefit with and without the RISE program from a provider (hospital) perspective. Nursing staff who used the RISE program between 2015 and 2016 at a 1000-bed, private hospital in the United States were included in the analysis. The cost of running the RISE program, nurse turnover, and nurse time off were modeled. Data on costs were obtained from literature review and hospital data. Probabilities of quitting or taking time off with or without the RISE program were estimated using survey data. Net monetary benefit (NMB) and budget impact of having the RISE program were computed to determine cost benefit to the hospital. Expected model results of the RISE program found a net monetary benefit savings of US $22,576.05 per nurse who initiated a RISE call. These savings were determined to be 99.9% consistent on the basis of a probabilistic sensitivity analysis. The budget impact analysis revealed that a hospital could save US $1.81 million each year because of the RISE program. The RISE program resulted in substantial cost savings to the hospital. Hospitals should be encouraged by these findings to implement institution-wide support programs for medical staff, based on a high demand for this type of service and the potential for cost savings.

Comparisons of population subgroups performance on a keyboard psychomotor task

NASA Technical Reports Server (NTRS)

Stapleford, R. L.

1973-01-01

Response time and pass/fail data were obtained from 163 subjects performing a psychomotor task. The basic task comprised a random five digit number briefly displayed to the subject at the start of each trail, and the keyboard on which the subject was to enter the number as fast as he could accurately do so after the display was extinguished. Some tests were run with the addition of a secondary task which required the subject to respond to a displayed light appearing at a random time. Matched pairs of subjects were selected from the group to analyze the effects of age, sex, intelligence, prior keyboard skill, and drinking habits. There was little or no effect due to age or drinking habits. Differences in response time were: average IQ subjects faster than low IQ subjects by 0.5 to 0.6 sec; subjects with prior keyboard skill faster by 0.4 to 0.5 sec; and female subjects faster by 0.2 to 0.3 sec. These effects were generally insensitive to the presence of the secondary task.

Specificity of diffusion channels produced by lambda phage receptor protein of Escherichia coli.

PubMed Central

Luckey, M; Nikaido, H

1980-01-01

The lamB protein, the receptor for phage lambda, was purified from the outer membrane of Escherichia coli K-12 by extraction with Triton X-100 and EDTA, chromatography on DEAE-Sephacel in Triton X-100, exchange of Triton for cholate by gel filtration, and chromatography on Sephacryl S-200 in cholate, NaCl, and EDTA. The purified protein appeared to exist as several oligomeric species. In an equilibrium retention assay with reconstituted vesicles containing phospholipids and lipopolysaccharide, the lamB protein conferred permeability for disaccharides. In a liposome swelling assay designed to measure rates of diffusion, the lamB protein conferred permeability to phospholipid liposomes for a variety of substrates. The rates obtained indicate the permeation facilitated by the lamB protein is specific, discriminating among substrates by both size and configuration. For example, maltose diffused into liposomes 40 times faster than sucrose, about 8 times faster than cellobiose, and about 12 times faster than maltoheptaose. The results suggest that the lamB protein forms a transmembrane channel containing a site (or sites) that loosely interacts with the solutes. Images PMID:6444720

Faster and More Accurate Transport Procedures for HZETRN

NASA Technical Reports Server (NTRS)

Slaba, Tony C.; Blattnig, Steve R.; Badavi, Francis F.

2010-01-01

Several aspects of code verification are examined for HZETRN. First, a detailed derivation of the numerical marching algorithms is given. Next, a new numerical method for light particle transport is presented, and improvements to the heavy ion transport algorithm are discussed. A summary of various coding errors is also given, and the impact of these errors on exposure quantities is shown. Finally, a coupled convergence study is conducted. From this study, it is shown that past efforts in quantifying the numerical error in HZETRN were hindered by single precision calculations and computational resources. It is also determined that almost all of the discretization error in HZETRN is caused by charged target fragments below 50 AMeV. Total discretization errors are given for the old and new algorithms, and the improved accuracy of the new numerical methods is demonstrated. Run time comparisons are given for three applications in which HZETRN is commonly used. The new algorithms are found to be almost 100 times faster for solar particle event simulations and almost 10 times faster for galactic cosmic ray simulations.

Comparison of vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification systems.

PubMed

Han, Young Keun; Miller, Kevin M

2009-08-01

To compare vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification machines. Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA. The vacuum rise time under normal and enhanced aspiration modes, vacuum limit accuracy, and occlusion break surge of the Infiniti Vision System, Stellaris Vision Enhancement System, and WhiteStar Signature Phacoemulsification System were tested. Vacuum rise time and limit accuracy were measured at limit settings of 400 mm Hg and 600 mm Hg. Surge area was recorded at vacuum limit settings of 200 mm Hg, 300 mm Hg, 400 mm Hg, and 500 mm Hg. The Infiniti had the fastest vacuum rise times under normal and enhanced aspiration modes. At 4 seconds, the vacuum limit accuracy was greatest with the Infiniti at the 400 mm Hg limit and the Signature at the 600 mm Hg limit. The Stellaris did not reach either vacuum target. The Infiniti performed better than the other 2 machines during testing of occlusion break surge at all vacuum limit settings above 200 mm Hg. Under controlled laboratory test conditions, the Infiniti had the fastest vacuum rise time, greatest vacuum limit accuracy at 400 mm Hg, and least occlusion break surge. These results can be explained by the lower compliance of the Infiniti system.

Investigating the Mpemba Effect: When Hot Water Freezes Faster than Cold Water

ERIC Educational Resources Information Center

Ibekwe, R. T.; Cullerne, J. P.

2016-01-01

Under certain conditions a body of hot liquid may cool faster and freeze before a body of colder liquid, a phenomenon known as the Mpemba Effect. An initial difference in temperature of 3.2 °C enabled warmer water to reach 0 °C in 14% less time than colder water. Convection currents in the liquid generate a temperature gradient that causes more…

The man-made creators of the imbalance of water in Nature

NASA Astrophysics Data System (ADS)

Shlafman, L. M.; Kontar, V. A.

2013-12-01

At 2011 we have described the imbalance of water in Nature as the system [1]. At 2012 we have described water and carbon and the glaciers [2], [3] as creators of the imbalance of Nature. Now we are describing some man-made creators of the imbalance of Nature. The photosynthesis is a powerful creator of the imbalance of Nature. The photosynthesis significantly increases the complexity of the structures and reduces the entropy. Earth's hydrosphere contains water less than it was flowed via photosynthesis. This is an example of the imbalance of involving when the return of water has delayed because water is involved into the processes of life and other processes. People widely use photosynthesis and create not only an additional man-made imbalance of water in Nature, but also the man-made changing the albedo, and a lot of other important parameters of the planet of Earth. All of these processes are significantly imbalanced. The fossil hydrocarbons have accumulated during millions of years, but now are burned. This is an example of the imbalance delay by time. The man-made burning of the hydrocarbons is creating the imbalances of impact or explosive type, because of the burning processes is in millions of times faster than the accumulation processes. Please pay attention to the imbalance of redeployment by places. For example, oil and gas are extracted in one places, and burned in others. During combustion is standing out not only water, but energy, and other components. The temperature in the centers of big cities is always higher and there is dominating the rising air. It pollutes the environment, changes circulations, create greenhouse effect, etc. Other examples of the imbalance of relocation are shown in the production and consumption of food. The irrigation systems transfer water from one place to another. This transfer of water creates a lot of imbalances in change climate, ecosystems, etc in places where water was took and where the water was brought. Usually these are different places where the water taken, where the water used to grow crops, where the crop had eaten and where waste throw out. It creates a lot of the man-made imbalances of redeployment, which generate the new chains of different types of the man-made imbalances of water, other components and processes. The waste is one of the most important man-made creators of the imbalance of Nature. Some of water from the waste comes back into circulation in the clean or dirty conditions. Another part of water from waste will join into numerous water-based or water-use components of Nature, and fall out of the hydrological cycle for a long time. The quantity and diversity of waste are rising much faster than the recycles industries and it is creating a lot of dangerous imbalances of Nature. The wastes are is the time bombs, which man made, and which will soon explode. The traditional balanced science and practice are not prepared to deal with the waste problem. The concept of the imbalance of Nature can help prevent this catastrophic explosion. People are creating a lot of the man-made imbalances of Nature which bring the dangerous 'unexpected surprises'. The concept of the imbalance of Nature give possibilities to create the man-made imbalances of Nature with the predictable parameters and it can help do Mother Nature to be friendlier to humanity.

Eldecalcitol improves chair-rising time in postmenopausal osteoporotic women treated with bisphosphonates

PubMed Central

Iwamoto, Jun; Sato, Yoshihiro

2014-01-01

An open-label randomized controlled trial was conducted to clarify the effect of eldecalcitol (ED) on body balance and muscle power in postmenopausal osteoporotic women treated with bisphosphonates. A total of 106 postmenopausal women with osteoporosis (mean age 70.8 years) were randomly divided into two groups (n=53 in each group): a bisphosphonate group (control group) and a bisphosphonate plus ED group (ED group). Biochemical markers, unipedal standing time (body balance), and five-repetition chair-rising time (muscle power) were evaluated. The duration of the study was 6 months. Ninety-six women who completed the trial were included in the subsequent analyses. At baseline, the age, body mass index, bone mass indices, bone turnover markers, unipedal standing time, and chair-rising time did not differ significantly between the two groups. During the 6-month treatment period, bone turnover markers decreased significantly from the baseline values similarly in the two groups. Although no significant improvement in the unipedal standing time was seen in the ED group, compared with the control group, the chair-rising time decreased significantly in the ED group compared with the control group. The present study showed that ED improved the chair-rising time in terms of muscle power in postmenopausal osteoporotic women treated with bisphosphonates. PMID:24476669

Low-stringency selection of TEM1 for BLIP shows interface plasticity and selection for faster binders

PubMed Central

Cohen-Khait, Ruth; Schreiber, Gideon

2016-01-01

Protein–protein interactions occur via well-defined interfaces on the protein surface. Whereas the location of homologous interfaces is conserved, their composition varies, suggesting that multiple solutions may support high-affinity binding. In this study, we examined the plasticity of the interface of TEM1 β-lactamase with its protein inhibitor BLIP by low-stringency selection of a random TEM1 library using yeast surface display. Our results show that most interfacial residues could be mutated without a loss in binding affinity, protein stability, or enzymatic activity, suggesting plasticity in the interface composition supporting high-affinity binding. Interestingly, many of the selected mutations promoted faster association. Further selection for faster binders was achieved by drastically decreasing the library–ligand incubation time to 30 s. Preequilibrium selection as suggested here is a novel methodology for specifically selecting faster-associating protein complexes. PMID:27956635

Joint compensation scheme of polarization crosstalk, intersymbol interference, frequency offset, and phase noise based on cascaded Kalman filter

NASA Astrophysics Data System (ADS)

Zhang, Qun; Yang, Yanfu; Xiang, Qian; Zhou, Zhongqing; Yao, Yong

2018-02-01

A joint compensation scheme based on cascaded Kalman filter is proposed, which can implement polarization tracking, channel equalization, frequency offset, and phase noise compensation simultaneously. The experimental results show that the proposed algorithm can not only compensate multiple channel impairments simultaneously but also improve the polarization tracking capacity and accelerate the convergence speed. The scheme has up to eight times faster convergence speed compared with radius-directed equalizer (RDE) + Max-FFT (maximum fast Fourier transform) + BPS (blind phase search) and can track up polarization rotation 60 times and 15 times faster than that of RDE + Max-FFT + BPS and CMMA (cascaded multimodulus algorithm) + Max-FFT + BPS, respectively.

Discriminating cosmic muons and X-rays based on rise time using a GEM detector

NASA Astrophysics Data System (ADS)

Wu, Hui-Yin; Zhao, Sheng-Ying; Wang, Xiao-Dong; Zhang, Xian-Ming; Qi, Hui-Rong; Zhang, Wei; Wu, Ke-Yan; Hu, Bi-Tao; Zhang, Yi

2016-08-01

Gas electron multiplier (GEM) detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold. Supported by National Natural Science Foundation of China (11135002, 11275235, 11405077, 11575073)

Faster simulation plots

NASA Technical Reports Server (NTRS)

Fowell, Richard A.

1989-01-01

Most simulation plots are heavily oversampled. Ignoring unnecessary data points dramatically reduces plot time with imperceptible effect on quality. The technique is suited to most plot devices. The departments laser printer's speed was tripled for large simulation plots by data thinning. This reduced printer delays without the expense of a faster laser printer. Surpisingly, it saved computer time as well. All plot data are now thinned, including PostScript and terminal plots. The problem, solution, and conclusions are described. The thinning algorithm is described and performance studies are presented. To obtain FORTRAN 77 or C source listings, mail a SASE to the author.

Kinetic fractionation of stable nitrogen isotopes during amino acid transamination

NASA Astrophysics Data System (ADS)

Macko, Stephen A.; Estep, Marilyn L. Fogel; Engel, Michael H.; Hare, P. E.

1986-10-01

This study evaluates a kinetic isotope effect involving 15N, during the transamination reactions catalyzed by glutamic oxalacetic transaminase. During the transfer of amino nitrogen from glutamic acid to oxaloacetate to form aspartic acid, 14NH 2 reacted 1.0083 times faster than 14NH 2. In the reverse reaction transferring NH 2 from aspartic acid to α-ketoglutarate, 14NH 2 was incorporated 1.0017 times faster than 15NH 2. Knowledge of the magnitude and sign of these isotope effects will be useful in the interpretation of the distribution of 15N in biological and geochemical systems.

Under the Lens: Investigating the Sun's Mysteries

NASA Astrophysics Data System (ADS)

Harwood, William; Klotz, Irene

2008-11-01

Sometime around 2012, the waxing 11-year solar cycle once again will reach its peak. Between now and then, magnetically turbulent sunspots, spawned by some still mysterious process, will form near the poles in increasing numbers and migrate toward the Sun's faster-rotating equator in pairs of opposite polarity. Titanic magnetic storms will rage as immense flux tubes rise to the surface in active regions around sunspots and spread out in a boiling sea of electric charge. Magnetic field lines across an enormous range of scales will arc and undulate, rip apart and reconnect, heating the Sun's upper atmosphere and occasionally triggering brilliant flares and multibillion-megaton coronal mass ejections (CMEs) that travel through the solar wind and slam into Earth.

Nutritional requirements of young soccer players.

PubMed

Bar-Or, O; Unnithan, V B

1994-01-01

The general dietary needs of the young soccer player appear to be similar to those of the adult soccer player. There are, however, several age- and maturation-related differences. Compared with adults, children's daily recommended protein intake (per kg body mass) is higher; during exercise, children's muscles rely more on fat than on carbohydrates, but it is not clear whether young soccer players need higher dietary fat; calculated per kg body mass, the metabolic demands of walking and running are considerably higher in children; and during dehydration, children's core temperature rises faster, which calls for stricter enforcement of hydration. To increase fluid palatability, drinks should be flavoured, according to the child's individual preference. The efficacy and safety of 'carbohydrate loading' have not been studied in children.

Overheating instability of a thin conductor with respect to stratification

NASA Astrophysics Data System (ADS)

Garanin, S. F.; Kuznetsov, S. D.

2018-04-01

We consider an overheating instability of a thin (compared to the skin depth) conductor with respect to stratification at the stage when its resistivity rises up to an electrical explosion. Temperature perturbations under such conditions are shown to grow in proportion to resistivity. In the model, when resistivity is proportional to temperature, perturbations grow in proportion to temperature and hence exhibit no relative growth. For a conductor with initial thickness perturbations, temperature perturbations grow in proportion to resistivity and current action integral, i.e., somewhat faster than perturbations in the problem of constant thickness conductors. Comparison of our results with simulations of the growth of stratification during electrical heating of foils in warm dense matter generation systems demonstrates their close agreement.

Normal Stresses, Contraction, and Stiffening in Sheared Elastic Networks

NASA Astrophysics Data System (ADS)

Baumgarten, Karsten; Tighe, Brian P.

2018-04-01

When elastic solids are sheared, a nonlinear effect named after Poynting gives rise to normal stresses or changes in volume. We provide a novel relation between the Poynting effect and the microscopic Grüneisen parameter, which quantifies how stretching shifts vibrational modes. By applying this relation to random spring networks, a minimal model for, e.g., biopolymer gels and solid foams, we find that networks contract or develop tension because they vibrate faster when stretched. The amplitude of the Poynting effect is sensitive to the network's linear elastic moduli, which can be tuned via its preparation protocol and connectivity. Finally, we show that the Poynting effect can be used to predict the finite strain scale where the material stiffens under shear.

Chronotype, bed timing and total sleep time in seniors

PubMed Central

Monk, Timothy H.; Buysse, Daniel J.

2014-01-01

Many older adults (seniors) experience problems with getting enough sleep. Because of the link between sleep and circadian rhythms, changes in bedtime lead to changes in the amount of sleep obtained. Although primarily determined genetically, chronotype changes with advancing age towards a more morning-type (M-type) orientation. In a 2006 study, we have found a linear relationship, by which the earlier a senior’s bedtime, the more sleep she/he will obtain. The aim of this study was to see whether this relationship differs for M-type seniors, as compared to seniors outside the M-type category. Retired seniors (n = 954, 535 M, 410F, 65 years+, mean age 74.4 years) taking part in a telephone interview were divided into M-types and Other types (O-types) using the Composite Scale of Morningness (CSM). The relationship between bedtime and Total Sleep Time (TST), and between rise-time and TST, was tested using linear regression separately for M-types and O-types. For each participant, habitual bedtime, rise-time and total Sleep Time (TST) [after removing time spent in unwanted wakefulness] were obtained using a telephone version of the Sleep Timing Questionnaire (STQ). Both chronotype groups showed a significant linear relationship between bedtime and TST (p<0.001); with earlier bedtimes leading to more TST (M-type 5.6 min; O-type 4.4 min per 10 min change [slope difference p = 0.05]); and an opposite relationship between rise-time and TST with earlier rise-times leading to less TST (M-type 6.7 min; O-type 4.2 min per 10 min change [slope difference p 0.001]). M-types retired to bed 56 min earlier (p<0.001), awoke 93 min earlier (p<0.001) and obtained 23 min less TST (p<0.001) than O-types. In conclusion, both chronotypes showed TST to be related in a linear way to bedtime and rise-time; the overall shorter TST in M-types was due to them rising 93 min earlier, but only retiring to bed 56 min earlier than O-types; as well as having a steeper rise-time versus TST relationship. PMID:24517139

Short rise time intense electron beam generator

DOEpatents

Olson, Craig L.

1987-01-01

A generator for producing an intense relativistic electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

Short rise time intense electron beam generator

DOEpatents

Olson, C.L.

1984-03-16

A generator for producing an intense relativisitc electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

Meal size is a critical driver of weight gain in early childhood.

PubMed

Syrad, Hayley; Llewellyn, Clare H; Johnson, Laura; Boniface, David; Jebb, Susan A; van Jaarsveld, Cornelia H M; Wardle, Jane

2016-06-20

Larger serving sizes and more frequent eating episodes have been implicated in the rising prevalence of obesity at a population level. This study examines the relative contributions of meal size and frequency to weight gain in a large sample of British children. Using 3-day diet diaries from 1939 children aged 21 months from the Gemini twin cohort, we assessed prospective associations between meal size, meal frequency and weight gain from two to five years. Separate longitudinal analyses demonstrated that every 10 kcal increase in meal size was associated with 1.5 g/wk or 4% (p = 0.005) faster growth rate, while meal frequency was not independently associated with growth (β = 0.3 g/wk p = 0.20). Including both meal parameters in the model strengthened associations (meal size: β = 2.6 g/wk, p < 0.001; meal frequency: β = 1.0 g/wk, p = 0.001). Taken together, the implication is that meal size promotes faster growth regardless of frequency, but meal frequency has a significant effect only if meal size is assumed to be held constant. Clearer advice on meal size and frequency, especially advice on appropriate meal size, may help prevent excess weight gain.

VariantSpark: population scale clustering of genotype information.

PubMed

O'Brien, Aidan R; Saunders, Neil F W; Guo, Yi; Buske, Fabian A; Scott, Rodney J; Bauer, Denis C

2015-12-10

Genomic information is increasingly used in medical practice giving rise to the need for efficient analysis methodology able to cope with thousands of individuals and millions of variants. The widely used Hadoop MapReduce architecture and associated machine learning library, Mahout, provide the means for tackling computationally challenging tasks. However, many genomic analyses do not fit the Map-Reduce paradigm. We therefore utilise the recently developed SPARK engine, along with its associated machine learning library, MLlib, which offers more flexibility in the parallelisation of population-scale bioinformatics tasks. The resulting tool, VARIANTSPARK provides an interface from MLlib to the standard variant format (VCF), offers seamless genome-wide sampling of variants and provides a pipeline for visualising results. To demonstrate the capabilities of VARIANTSPARK, we clustered more than 3,000 individuals with 80 Million variants each to determine the population structure in the dataset. VARIANTSPARK is 80 % faster than the SPARK-based genome clustering approach, ADAM, the comparable implementation using Hadoop/Mahout, as well as ADMIXTURE, a commonly used tool for determining individual ancestries. It is over 90 % faster than traditional implementations using R and Python. The benefits of speed, resource consumption and scalability enables VARIANTSPARK to open up the usage of advanced, efficient machine learning algorithms to genomic data.

Cell surface domain specific postsynaptic currents evoked by identified GABAergic neurones in rat hippocampus in vitro

PubMed Central

Maccaferri, Gianmaria; David, J; Roberts, B; Szucs, Peter; Cottingham, Carol A; Somogyi, Peter

2000-01-01

Inhibitory postsynaptic currents (IPSCs) evoked in CA1 pyramidal cells (n = 46) by identified interneurones (n = 43) located in str. oriens were recorded in order to compare their functional properties and to determine the effect of synapse location on the apparent IPSC kinetics as recorded using somatic voltage clamp at −70 mV and nearly symmetrical [Cl−]. Five types of visualised presynaptic interneurone, oriens-lacunosum moleculare (O-LMC), basket (BC), axo-axonic (AAC), bistratified (BiC) and oriens-bistratified (O-BiC) cells, were distinguished by immunocytochemistry and/or synapse location using light and electron microscopy. Somatostatin immunoreactive O-LMCs, innervating the most distal dendritic shafts and spines, evoked the smallest amplitude (26 ± 10 pA, s.e.m., n = 8) and slowest IPSCs (10–90 % rise time, 6.2 ± 0.6 ms; decay, 20.8 ± 1.7 ms, n = 8), with no paired-pulse modulation of the second IPSC (93 ± 4 %) at 100 ms interspike interval. In contrast, parvalbumin-positive AACs evoked larger amplitude (308 ± 103 pA, n = 7) and kinetically faster (rise time, 0.8 ± 0.1 ms; decay 11.2 ± 0.9 ms, n = 7) IPSCs showing paired-pulse depression (to 68 ± 5 %, n = 6). Parvalbumin- or CCK-positive BCs (n = 9) terminating on soma/dendrites, BiCs (n = 4) and O-BiCs (n = 7) innervating dendrites evoked IPSCs with intermediate kinetic parameters. The properties of IPSCs and sensitivity to bicuculline indicated that they were mediated by GABAA receptors. In three cases, kinetically complex, multiphasic IPSCs, evoked by an action potential in the recorded basket cells, suggested that coupled interneurones, possibly through electrotonic junctions, converged on the same postsynaptic neurone. The population of O-BiCs (4 of 4 somatostatin positive) characterised in this study had horizontal dendrites restricted to str. oriens/alveus and innervated stratum radiatum and oriens. Other BiCs had radial dendrites as described earlier. The parameters of IPSCs evoked by BiCs and O-BiCs showed the largest cell to cell variation, and a single interneurone could evoke both small and slow as well as large and relatively fast IPSCs. The kinetic properties of the somatically recorded postsynaptic current are correlated with the innervated cell surface domain. A significant correlation of rise and decay times for the overall population of unitary IPSCs suggests that electrotonic filtering of distal responses is a major factor for the location and cell type specific differences of unitary IPSCs, but molecular heterogeneity of postsynaptic GABAA receptors may also contribute to the observed kinetic differences. Furthermore, domain specific differences in the short-term plasticity of the postsynaptic response indicate a differentiation of interneurones in activity-dependent responses. PMID:10747186

EARLY-PHASE PHOTOMETRY AND SPECTROSCOPY OF TRANSITIONAL TYPE Ia SN 2012ht: DIRECT CONSTRAINT ON THE RISE TIME

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

Yamanaka, Masayuki; Nogami, Daisaku; Maeda, Keiichi

We report photometric and spectroscopic observations of the nearby Type Ia Supernova (SN Ia) 2012ht from –15.8 days to +49.1 days after B-band maximum. The decline rate of the light curve is Δm {sub 15}(B) = 1.39 ± 0.05 mag, which is intermediate between normal and subluminous SNe Ia, and similar to that of the ''transitional'' Type Ia SN 2004eo. The spectral line profiles also closely resemble those of SN 2004eo. We were able to observe SN 2012ht at a very early phase, when it was still rising and was about three magnitudes fainter than at the peak. The rise time to the B-bandmore » maximum is estimated to be 17.6 ± 0.5 days and the time of the explosion is MJD 56277.98 ± 0.13. SN 2012ht is the first transitional SN Ia whose rise time is directly measured without using light curve templates, and the fifth SN Ia overall. This rise time is consistent with those of the other four SNe within the measurement error, even including the extremely early detection of SN 2013dy. The rising part of the light curve can be fitted by a quadratic function, and shows no sign of a shock-heating component due to the interaction of the ejecta with a companion star. The rise time is significantly longer than that inferred for subluminous SNe such as SN 1991bg, which suggests that a progenitor and/or explosion mechanism of transitional SNe Ia are more similar to normal SNe Ia rather than to subluminous SNe Ia.« less

Social Environment Shapes the Speed of Cooperation

PubMed Central

Nishi, Akihiro; Christakis, Nicholas A.; Evans, Anthony M.; O’Malley, A. James; Rand, David G.

2016-01-01

Are cooperative decisions typically made more quickly or slowly than non-cooperative decisions? While this question has attracted considerable attention in recent years, most research has focused on one-shot interactions. Yet it is repeated interactions that characterize most important real-world social interactions. In repeated interactions, the cooperativeness of one’s interaction partners (the “social environment”) should affect the speed of cooperation. Specifically, we propose that reciprocal decisions (choices that mirror behavior observed in the social environment), rather than cooperative decisions per se, occur more quickly. We test this hypothesis by examining four independent decision time datasets with a total of 2,088 subjects making 55,968 decisions. We show that reciprocal decisions are consistently faster than non-reciprocal decisions: cooperation is faster than defection in cooperative environments, while defection is faster than cooperation in non-cooperative environments. These differences are further enhanced by subjects’ previous behavior – reciprocal decisions are faster when they are consistent with the subject’s previous choices. Finally, mediation analyses of a fifth dataset suggest that the speed of reciprocal decisions is explained, in part, by feelings of conflict – reciprocal decisions are less conflicted than non-reciprocal decisions, and less decision conflict appears to lead to shorter decision times. PMID:27435940

The Impact of Increasing Carbon Dioxide on Ozone Recovery

NASA Technical Reports Server (NTRS)

Rosenfield, Joan E.; Douglass, Anne R.; Considine, David B.; Einaudi, Franco (Technical Monitor)

2001-01-01

We have used the GSFC coupled two-dimensional (2D) model to study the impact of increasing carbon dioxide from 1980 to 2050 on the recovery of ozone to its pre-1980 amounts. We find that the changes in temperature and circulation arising from increasing CO2 affect ozone recovery in a manner which varies greatly with latitude, altitude, and time of year. Middle and upper stratospheric ozone recovers faster at all latitudes due to a slowing of the ozone catalytic loss cycles. In the lower stratosphere, the recovery of tropical ozone is delayed due to a decrease in production and a speed up in the overturning circulation. The recovery of high northern latitude lower stratospheric ozone is delayed in spring and summer due to an increase in springtime heterogeneous chemical loss, and is speeded up in fall and winter due to increased downwelling. The net effect on the higher northern latitude column ozone is to slow down the recovery from late March to late July, while making it faster at other times. In the high southern latitudes, the impact of CO2 cooling is negligible. Annual mean column ozone is predicted to recover faster at all latitudes, and globally averaged ozone is predicted to recover approximately ten years faster as a result of increasing CO2.

Rise time measurement for ultrafast X-ray pulses

DOEpatents

Celliers, Peter M [Berkeley, CA; Weber, Franz A [Oakland, CA; Moon, Stephen J [Tracy, CA

2005-04-05

A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

Rise Time Measurement for Ultrafast X-Ray Pulses

DOEpatents

Celliers, Peter M.; Weber, Franz A.; Moon, Stephen J.

2005-04-05

A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

EFFECT OF ATHLETIC TAPING AND KINESIOTAPING® ON MEASUREMENTS OF FUNCTIONAL PERFORMANCE IN BASKETBALL PLAYERS WITH CHRONIC INVERSION ANKLE SPRAINS

PubMed Central

Karatas, Nihan; Baltaci, Gul

2012-01-01

Background: Chronic inversion ankle sprains are common in basketball players. The effect of taping on functional performance is disputed in the literature. Kinesiotaping® (KT®) is a new method that is being used as both a therapeutic and performance enhancement tool. To date, it appears that no study has investigated the effect of ankle KT® on functional performance. Purpose: To investigate the effects of different types of taping (KT® using Kinesio Tex®, athletic taping) on functional performance in athletes with chronic inversion sprains of the ankle. Study Design: Crossover Study Design Methods: Fifteen male basketball players with chronic inversion ankle sprains between the ages of 18 and 22 participated in this study. Functional performance tests (Hopping test by Amanda et al, Single Limb Hurdle Test, Standing Heel Rise test, Vertical Jump Test, The Star Excursion Balance Test [SEBT] and Kinesthetic Ability Trainer [KAT] Test) were used to quantify agility, endurance, balance, and coordination. These tests were conducted four times at one week intervals using varied conditions: placebo tape, without tape, standard athletic tape, and KT®. One-way ANOVA tests were used to examine difference in measurements between conditions. Bonferroni correction was applied to correct for repeated testing. Results: There were no significant differences among the results obtained using the four conditions for SEBT (anterior p=0.0699; anteromedial p=0.126; medial p=0.550; posteromedial p=0.587; posterior p=0.754; posterolateral p=0.907; lateral p=0.124; anterolateral p=0.963) and the KAT dynamic measurement (p=0.388). Faster performance times were measured with KT® and athletic tape in single limb hurdle test when compared to placebo and non-taped conditions (Athletic taping- placebo taping: p=0.03; athletic taping- non tape p=0.016;KT®- Placebo taping p=0.042; KT®-Non tape p=0.016). In standing heel rise test and vertical jump test, athletic taping led to decreased performance. (Standing heel rise test: Athletic taping- placebo taping p=0.035; athletic taping- non tape p=0.043; athletic tape- KT® p<0.001) (Vertical jump test: Athletic taping- placebo taping p=0.002: athletic taping- non tape p=0.002; KT®- athletic tape p<0.001) Conclusion: Kinesiotaping® had no negative effects on a battery of functional performance tests and improvements were seen in some functional performance tests. Clinical Relevance: Ankle taping using Kinesio Tex® Tape did not inhibit functional performance. PMID:22530190

Effect of athletic taping and kinesiotaping® on measurements of functional performance in basketball players with chronic inversion ankle sprains.

PubMed

Bicici, Seda; Karatas, Nihan; Baltaci, Gul

2012-04-01

Chronic inversion ankle sprains are common in basketball players. The effect of taping on functional performance is disputed in the literature. Kinesiotaping® (KT®) is a new method that is being used as both a therapeutic and performance enhancement tool. To date, it appears that no study has investigated the effect of ankle KT® on functional performance. To investigate the effects of different types of taping (KT® using Kinesio Tex®, athletic taping) on functional performance in athletes with chronic inversion sprains of the ankle. Crossover Study Design Fifteen male basketball players with chronic inversion ankle sprains between the ages of 18 and 22 participated in this study. Functional performance tests (Hopping test by Amanda et al, Single Limb Hurdle Test, Standing Heel Rise test, Vertical Jump Test, The Star Excursion Balance Test [SEBT] and Kinesthetic Ability Trainer [KAT] Test) were used to quantify agility, endurance, balance, and coordination. These tests were conducted four times at one week intervals using varied conditions: placebo tape, without tape, standard athletic tape, and KT®. One-way ANOVA tests were used to examine difference in measurements between conditions. Bonferroni correction was applied to correct for repeated testing. There were no significant differences among the results obtained using the four conditions for SEBT (anterior p=0.0699; anteromedial p=0.126; medial p=0.550; posteromedial p=0.587; posterior p=0.754; posterolateral p=0.907; lateral p=0.124; anterolateral p=0.963) and the KAT dynamic measurement (p=0.388). Faster performance times were measured with KT® and athletic tape in single limb hurdle test when compared to placebo and non-taped conditions (Athletic taping- placebo taping: p=0.03; athletic taping- non tape p=0.016;KT®- Placebo taping p=0.042; KT®-Non tape p=0.016). In standing heel rise test and vertical jump test, athletic taping led to decreased performance. (Standing heel rise test: Athletic taping- placebo taping p=0.035; athletic taping- non tape p=0.043; athletic tape- KT® p<0.001) (Vertical jump test: Athletic taping- placebo taping p=0.002: athletic taping- non tape p=0.002; KT®- athletic tape p<0.001) Kinesiotaping® had no negative effects on a battery of functional performance tests and improvements were seen in some functional performance tests. Ankle taping using Kinesio Tex® Tape did not inhibit functional performance.

The behavior of an opponent alters pacing decisions in 4-km cycling time trials.

PubMed

Konings, Marco J; Schoenmakers, Patrick P J M; Walker, Andrew J; Hettinga, Florentina J

2016-05-01

The present study aimed to explore how athletes respond to different behaviors of their opponents. Twelve moderately to highly physically active participants with at least two years of cycling experience completed four 4-km time trials on a Velotron cycle ergometer. After a familiarization time trial (FAM), participants performed three experimental time trials in randomized order with no opponent (NO), a virtual opponent who started slower and finished faster compared to FAM (OP-SLOWFAST), or a virtual opponent who started faster and finished slower compared to FAM (OP-FASTSLOW). Repeated-measures ANOVAs (P<0.05) were used to examine differences in pacing and performance related to power output, velocity and RPE. OP-SLOWFAST and OP-FASTSLOW were completed faster compared to NO (385.5±27.5, 385.0±28.6, and 390.6±29.3s, respectively). An interaction effect for condition×distance (F=3.944, P<0.001) indicated differences in pacing profiles between conditions. Post-hoc analysis revealed that a less aggressive starting strategy was adopted in NO compared to OP-FASTSLOW and OP-SLOWFAST during the initial 1000m. Finally, a faster starting opponent evokes higher power outputs by the participants in the initial 750m compared to a slower starting opponent. The present study is the first to show that the behavior of an opponent affects pacing-related decisions in laboratory-controlled conditions. Our findings support the recently proposed interdependence of perception and action, and emphasize the interaction with the environment as an important determinant for an athlete's pacing decisions, especially during the initial stages of a race. Copyright © 2016 Elsevier Inc. All rights reserved.

Control of the Ability of Profilin to Bind and Facilitate Nucleotide Exchange from G-actin*

PubMed Central

Wen, Kuo-Kuang; McKane, Melissa; Houtman, Jon C. D.; Rubenstein, Peter A.

2008-01-01

A major factor in profilin regulation of actin cytoskeletal dynamics is its facilitation of G-actin nucleotide exchange. However, the mechanism of this facilitation is unknown. We studied the interaction of yeast (YPF) and human profilin 1 (HPF1) with yeast and mammalian skeletal muscle actins. Homologous pairs (YPF and yeast actin, HPF1 and muscle actin) bound more tightly to one another than heterologous pairs. However, with saturating profilin, HPF1 caused a faster etheno-ATP exchange with both yeast and muscle actins than did YPF. Based on the -fold change in ATP exchange rate/Kd, however, the homologous pairs are more efficient than the heterologous pairs. Thus, strength of binding of profilin to actin and nucleotide exchange rate are not tightly coupled. Actin/HPF interactions were entropically driven, whereas YPF interactions were enthalpically driven. Hybrid yeast actins containing subdomain 1 (sub1) or subdomain 1 and 2 (sub12) muscle actin residues bound more weakly to YPF than did yeast actin (Kd = 2 μm versus 0.6 μm). These hybrids bound even more weakly to HPF than did yeast actin (Kd = 5 μm versus 3.2 μm). sub1/YPF interactions were entropically driven, whereas the sub12/YPF binding was enthalpically driven. Compared with WT yeast actin, YPF binding to sub1 occurred with a 5 times faster koff and a 2 times faster kon. sub12 bound with a 3 times faster koff and a 1.5 times slower kon. Profilin controls the energetics of its interaction with nonhybrid actin, but interactions between actin subdomains 1 and 2 affect the topography of the profilin binding site. PMID:18223293

Comparison of occlusion break responses and vacuum rise times of phacoemulsification systems.

PubMed

Sharif-Kashani, Pooria; Fanney, Douglas; Injev, Val

2014-07-30

Occlusion break surge during phacoemulsification cataract surgery can lead to potential surgical complications. The purpose of this study was to quantify occlusion break surge and vacuum rise time of current phacoemulsification systems used in cataract surgery. Occlusion break surge at vacuum pressures between 200 and 600 mmHg was assessed with the Infiniti® Vision System, the WhiteStar Signature® Phacoemulsification System, and the Centurion® Vision System using gravity-fed fluidics. Centurion Active FluidicsTM were also tested at multiple intraoperative pressure target settings. Vacuum rise time was evaluated for Infiniti, WhiteStar Signature, Centurion, and Stellaris® Vision Enhancement systems. Rise time to vacuum limits of 400 and 600 mmHg was assessed at flow rates of 30 and 60 cc/minute. Occlusion break surge was analyzed by 2-way analysis of variance. The Centurion system exhibited substantially less occlusion break surge than the other systems tested. Surge area with Centurion Active Fluidics was similar to gravity fluidics at an equivalent bottle height. At all Centurion Active Fluidics intraoperative pressure target settings tested, surge was smaller than with Infiniti and WhiteStar Signature. Infiniti had the fastest vacuum rise time and Stellaris had the slowest. No system tested reached the 600-mmHg vacuum limit. In this laboratory study, Centurion had the least occlusion break surge and similar vacuum rise times compared with the other systems tested. Reducing occlusion break surge may increase safety of phacoemulsification cataract surgery.

Comparison of occlusion break responses and vacuum rise times of phacoemulsification systems

PubMed Central

2014-01-01

Background Occlusion break surge during phacoemulsification cataract surgery can lead to potential surgical complications. The purpose of this study was to quantify occlusion break surge and vacuum rise time of current phacoemulsification systems used in cataract surgery. Methods Occlusion break surge at vacuum pressures between 200 and 600 mmHg was assessed with the Infiniti® Vision System, the WhiteStar Signature® Phacoemulsification System, and the Centurion® Vision System using gravity-fed fluidics. Centurion Active FluidicsTM were also tested at multiple intraoperative pressure target settings. Vacuum rise time was evaluated for Infiniti, WhiteStar Signature, Centurion, and Stellaris® Vision Enhancement systems. Rise time to vacuum limits of 400 and 600 mmHg was assessed at flow rates of 30 and 60 cc/minute. Occlusion break surge was analyzed by 2-way analysis of variance. Results The Centurion system exhibited substantially less occlusion break surge than the other systems tested. Surge area with Centurion Active Fluidics was similar to gravity fluidics at an equivalent bottle height. At all Centurion Active Fluidics intraoperative pressure target settings tested, surge was smaller than with Infiniti and WhiteStar Signature. Infiniti had the fastest vacuum rise time and Stellaris had the slowest. No system tested reached the 600-mmHg vacuum limit. Conclusions In this laboratory study, Centurion had the least occlusion break surge and similar vacuum rise times compared with the other systems tested. Reducing occlusion break surge may increase safety of phacoemulsification cataract surgery. PMID:25074069

SW#db: GPU-Accelerated Exact Sequence Similarity Database Search.

PubMed

Korpar, Matija; Šošić, Martin; Blažeka, Dino; Šikić, Mile

2015-01-01

In recent years we have witnessed a growth in sequencing yield, the number of samples sequenced, and as a result-the growth of publicly maintained sequence databases. The increase of data present all around has put high requirements on protein similarity search algorithms with two ever-opposite goals: how to keep the running times acceptable while maintaining a high-enough level of sensitivity. The most time consuming step of similarity search are the local alignments between query and database sequences. This step is usually performed using exact local alignment algorithms such as Smith-Waterman. Due to its quadratic time complexity, alignments of a query to the whole database are usually too slow. Therefore, the majority of the protein similarity search methods prior to doing the exact local alignment apply heuristics to reduce the number of possible candidate sequences in the database. However, there is still a need for the alignment of a query sequence to a reduced database. In this paper we present the SW#db tool and a library for fast exact similarity search. Although its running times, as a standalone tool, are comparable to the running times of BLAST, it is primarily intended to be used for exact local alignment phase in which the database of sequences has already been reduced. It uses both GPU and CPU parallelization and was 4-5 times faster than SSEARCH, 6-25 times faster than CUDASW++ and more than 20 times faster than SSW at the time of writing, using multiple queries on Swiss-prot and Uniref90 databases.

a Study of Women Engineering Students and Time to Completion of First-Year Required Courses at Texas A&M University

NASA Astrophysics Data System (ADS)

Kimball, Jorja; Cole, Bryan; Hobson, Margaret; Watson, Karan; Stanley, Christine

This paper reports findings on gender that were part of a larger study reviewing time to completion of course work that includes the first two semesters of calculus, chemistry, and physics, which are often considered the stumbling points or "barrier courses" to an engineering baccalaureate degree. Texas A&M University terms these courses core body of knowledge (CBK), and statistical analysis was conducted on two cohorts of first-year enrolling engineering students at the institution. Findings indicate that gender is statistically significantly related to completion of CBK with female engineering students completing required courses faster than males at the .01 level (p = 0.008). Statistical significance for gender and ethnicity was found between white male and white female students at the .01 level (p = 0.008). Descriptive analysis indicated that of the five majors studied (chemical, civil, computer, electrical, and mechanical engineering), women completed CBK faster than men, and African American and Hispanic women completed CBK faster than males of the same ethnicity.

Improved knowledge diffusion model based on the collaboration hypernetwork

NASA Astrophysics Data System (ADS)

Wang, Jiang-Pan; Guo, Qiang; Yang, Guang-Yong; Liu, Jian-Guo

2015-06-01

The process for absorbing knowledge becomes an essential element for innovation in firms and in adapting to changes in the competitive environment. In this paper, we present an improved knowledge diffusion hypernetwork (IKDH) model based on the idea that knowledge will spread from the target node to all its neighbors in terms of the hyperedge and knowledge stock. We apply the average knowledge stock V(t) , the variable σ2(t) , and the variance coefficient c(t) to evaluate the performance of knowledge diffusion. By analyzing different knowledge diffusion ways, selection ways of the highly knowledgeable nodes, hypernetwork sizes and hypernetwork structures for the performance of knowledge diffusion, results show that the diffusion speed of IKDH model is 3.64 times faster than that of traditional knowledge diffusion (TKDH) model. Besides, it is three times faster to diffuse knowledge by randomly selecting "expert" nodes than that by selecting large-hyperdegree nodes as "expert" nodes. Furthermore, either the closer network structure or smaller network size results in the faster knowledge diffusion.

Irreversible Local Markov Chains with Rapid Convergence towards Equilibrium.

PubMed

Kapfer, Sebastian C; Krauth, Werner

2017-12-15

We study the continuous one-dimensional hard-sphere model and present irreversible local Markov chains that mix on faster time scales than the reversible heat bath or Metropolis algorithms. The mixing time scales appear to fall into two distinct universality classes, both faster than for reversible local Markov chains. The event-chain algorithm, the infinitesimal limit of one of these Markov chains, belongs to the class presenting the fastest decay. For the lattice-gas limit of the hard-sphere model, reversible local Markov chains correspond to the symmetric simple exclusion process (SEP) with periodic boundary conditions. The two universality classes for irreversible Markov chains are realized by the totally asymmetric SEP (TASEP), and by a faster variant (lifted TASEP) that we propose here. We discuss how our irreversible hard-sphere Markov chains generalize to arbitrary repulsive pair interactions and carry over to higher dimensions through the concept of lifted Markov chains and the recently introduced factorized Metropolis acceptance rule.

Irreversible Local Markov Chains with Rapid Convergence towards Equilibrium

NASA Astrophysics Data System (ADS)

Kapfer, Sebastian C.; Krauth, Werner

2017-12-01

We study the continuous one-dimensional hard-sphere model and present irreversible local Markov chains that mix on faster time scales than the reversible heat bath or Metropolis algorithms. The mixing time scales appear to fall into two distinct universality classes, both faster than for reversible local Markov chains. The event-chain algorithm, the infinitesimal limit of one of these Markov chains, belongs to the class presenting the fastest decay. For the lattice-gas limit of the hard-sphere model, reversible local Markov chains correspond to the symmetric simple exclusion process (SEP) with periodic boundary conditions. The two universality classes for irreversible Markov chains are realized by the totally asymmetric SEP (TASEP), and by a faster variant (lifted TASEP) that we propose here. We discuss how our irreversible hard-sphere Markov chains generalize to arbitrary repulsive pair interactions and carry over to higher dimensions through the concept of lifted Markov chains and the recently introduced factorized Metropolis acceptance rule.

Optimal Padding for the Two-Dimensional Fast Fourier Transform

NASA Technical Reports Server (NTRS)

Dean, Bruce H.; Aronstein, David L.; Smith, Jeffrey S.

2011-01-01

One-dimensional Fast Fourier Transform (FFT) operations work fastest on grids whose size is divisible by a power of two. Because of this, padding grids (that are not already sized to a power of two) so that their size is the next highest power of two can speed up operations. While this works well for one-dimensional grids, it does not work well for two-dimensional grids. For a two-dimensional grid, there are certain pad sizes that work better than others. Therefore, the need exists to generalize a strategy for determining optimal pad sizes. There are three steps in the FFT algorithm. The first is to perform a one-dimensional transform on each row in the grid. The second step is to transpose the resulting matrix. The third step is to perform a one-dimensional transform on each row in the resulting grid. Steps one and three both benefit from padding the row to the next highest power of two, but the second step needs a novel approach. An algorithm was developed that struck a balance between optimizing the grid pad size with prime factors that are small (which are optimal for one-dimensional operations), and with prime factors that are large (which are optimal for two-dimensional operations). This algorithm optimizes based on average run times, and is not fine-tuned for any specific application. It increases the amount of times that processor-requested data is found in the set-associative processor cache. Cache retrievals are 4-10 times faster than conventional memory retrievals. The tested implementation of the algorithm resulted in faster execution times on all platforms tested, but with varying sized grids. This is because various computer architectures process commands differently. The test grid was 512 512. Using a 540 540 grid on a Pentium V processor, the code ran 30 percent faster. On a PowerPC, a 256x256 grid worked best. A Core2Duo computer preferred either a 1040x1040 (15 percent faster) or a 1008x1008 (30 percent faster) grid. There are many industries that can benefit from this algorithm, including optics, image-processing, signal-processing, and engineering applications.

Temporal predictive mechanisms modulate motor reaction time during initiation and inhibition of speech and hand movement.

PubMed

Johari, Karim; Behroozmand, Roozbeh

2017-08-01

Skilled movement is mediated by motor commands executed with extremely fine temporal precision. The question of how the brain incorporates temporal information to perform motor actions has remained unanswered. This study investigated the effect of stimulus temporal predictability on response timing of speech and hand movement. Subjects performed a randomized vowel vocalization or button press task in two counterbalanced blocks in response to temporally-predictable and unpredictable visual cues. Results indicated that speech and hand reaction time was decreased for predictable compared with unpredictable stimuli. This finding suggests that a temporal predictive code is established to capture temporal dynamics of sensory cues in order to produce faster movements in responses to predictable stimuli. In addition, results revealed a main effect of modality, indicating faster hand movement compared with speech. We suggest that this effect is accounted for by the inherent complexity of speech production compared with hand movement. Lastly, we found that movement inhibition was faster than initiation for both hand and speech, suggesting that movement initiation requires a longer processing time to coordinate activities across multiple regions in the brain. These findings provide new insights into the mechanisms of temporal information processing during initiation and inhibition of speech and hand movement. Copyright © 2017 Elsevier B.V. All rights reserved.

Gynaecological cancer pathway for faster cancer treatment: a clinical audit.

PubMed

Askew, Catherine; Gangji, Anand

2016-10-28

Gynaecological cancers make up 10% of cancer cases and 10% of female cancer deaths in New Zealand. The services for investigation and treatment of these women are regionally specific rather than centrally organised; hence we need appropriate standards of service and clear pathways for communication and management of these patients to ensure consistent care that is in line with the Ministry of Health goals for faster cancer treatment. The aim of this audit is to ensure faster gynaecological cancer management pathways for Northland patients. There were 72 gynaecological cancer cases identified from the gynaecological oncology referral data. These were the patients referred for multidisciplinary discussion of their newly diagnosed gynaecological cancer from June 2014-June 2015. Seventeen cases were excluded from this audit. The patients' information regarding their health care during the investigation and treatment of their cancer was obtained via an electronic patient record system. The time taken for each patient to complete various investigation, referrals, decisions and treatment was then compared against Ministry of Health faster cancer treatment targets and standards of service provision. The results showed that the overall target of patients having their first treatment within 62 days of initial referral for suspected cancer was being met only in 39% of cases. The best performing area of the pathway was the time from first referral from Northland DHB until the date of the first MDM discussion for a patient with an aim of ≤14 days with 93% of cases meeting this. The worst performing area was the time from decision to biopsy for tissue diagnosis to the time the histology report was produced, aiming for ≤14 days. We met this target in only 35% of cases. Over half of Northland patients are not receiving treatment in time that meets national targets. This delay seems to be mainly at the tissue diagnosis stage especially if operative intervention is required and while waiting on a management plan from the multidisciplinary team. Further input into appropriate tracking of cancer patients, management of prioritisation of operating lists and perhaps increased theatre time for gynaecology cancer patients should be considered. Increasing the frequency of multidisciplinary meetings for management plan decisions to be made should also be considered. The standards for service provision should also be altered to have a time course for referral, investigation and management that is in line with the Ministry faster cancer treatment targets.

Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

NASA Technical Reports Server (NTRS)

Hecox, K.; Squires, N.; Galambos, R.

1975-01-01

Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise burst duration (on-time) inter-burst interval (off-time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise-time but was unaffected by changes in fall-time. The amplitude of wave V was insensitive to changes in signal rise-and-fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It is concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

A comparative study of visual reaction time in table tennis players and healthy controls.

PubMed

Bhabhor, Mahesh K; Vidja, Kalpesh; Bhanderi, Priti; Dodhia, Shital; Kathrotia, Rajesh; Joshi, Varsha

2013-01-01

Visual reaction time is time required to response to visual stimuli. The present study was conducted to measure visual reaction time in 209 subjects, 50 table tennis (TT) players and 159 healthy controls. The visual reaction time was measured by the direct RT computerized software in healthy controls and table tennis players. Simple visual reaction time was measured. During the reaction time testing, visual stimuli were given for eighteen times and average reaction time was taken as the final reaction time. The study shows that table tennis players had faster reaction time than healthy controls. On multivariate analysis, it was found that TT players had 74.121 sec (95% CI 98.8 and 49.4 sec) faster reaction time compared to non-TT players of same age and BMI. Also playing TT has a profound influence on visual reaction time than BMI. Our study concluded that persons involved in sports are having good reaction time as compared to controls. These results support the view that playing of table tennis is beneficial to eye-hand reaction time, improve the concentration and alertness.

Impact of a COPD discharge care bundle on readmissions following admission with acute exacerbation: interrupted time series analysis.

PubMed

Laverty, Anthony A; Elkin, Sarah L; Watt, Hilary C; Millett, Christopher; Restrick, Louise J; Williams, Sian; Bell, Derek; Hopkinson, Nicholas S

2015-01-01

We evaluated the impact of a COPD discharge care bundle on readmission rates following hospitalisation with an acute exacerbation. Interrupted time series analysis, comparing readmission rates for COPD exacerbations at nine trusts that introduced the bundle, to two comparison groups; (1) other NHS trusts in London and (2) all other NHS trusts in England. Care bundles were implemented at different times for different NHS trusts, ranging from October 2009 to April 2011. Nine NHS acute trusts in the London, England. Patients aged 45 years and older admitted to an NHS acute hospital in England for acute exacerbation of COPD. Data come from Hospital Episode Statistics, April 2002 to March 2012. Annual trend readmission rates (and in total bed days) within 7, 28 and 90 days, before and after implementation. In hospitals introducing the bundle readmission rates were rising before implementation and falling afterwards (e.g. readmissions within 28 days +2.13% per annum (pa) pre and -5.32% pa post (p for difference in trends = 0.012)). Following implementation, readmission rates within 7 and 28 day were falling faster than among other trusts in London, although this was not statistically significant (e.g. readmissions within 28 days -4.6% pa vs. -3.2% pa, p = 0.44). Comparisons with a national control group were similar. The COPD discharge care bundle appeared to be associated with a reduction in readmission rate among hospitals using it. The significance of this is unclear because of changes to background trends in London and nationally.

Transformation of the neural code for tactile detection from thalamus to cortex.

PubMed

Vázquez, Yuriria; Salinas, Emilio; Romo, Ranulfo

2013-07-09

To understand how sensory-driven neural activity gives rise to perception, it is essential to characterize how various relay stations in the brain encode stimulus presence. Neurons in the ventral posterior lateral (VPL) nucleus of the somatosensory thalamus and in primary somatosensory cortex (S1) respond to vibrotactile stimulation with relatively slow modulations (∼100 ms) of their firing rate. In addition, faster modulations (∼10 ms) time-locked to the stimulus waveform are observed in both areas, but their contribution to stimulus detection is unknown. Furthermore, it is unclear whether VPL and S1 neurons encode stimulus presence with similar accuracy and via the same response features. To address these questions, we recorded single neurons while trained monkeys judged the presence or absence of a vibrotactile stimulus of variable amplitude, and their activity was analyzed with a unique decoding method that is sensitive to the time scale of the firing rate fluctuations. We found that the maximum detection accuracy of single neurons is similar in VPL and S1. However, VPL relies more heavily on fast rate modulations than S1, and as a consequence, the neural code in S1 is more tolerant: its performance degrades less when the readout method or the time scale of integration is suboptimal. Therefore, S1 neurons implement a more robust code, one less sensitive to the temporal integration window used to infer stimulus presence downstream. The differences between VPL and S1 responses signaling the appearance of a stimulus suggest a transformation of the neural code from thalamus to cortex.

Content-specific evidence accumulation in inferior temporal cortex during perceptual decision-making

PubMed Central

Tremel, Joshua J.; Wheeler, Mark E.

2015-01-01

During a perceptual decision, neuronal activity can change as a function of time-integrated evidence. Such neurons may serve as decision variables, signaling a choice when activity reaches a boundary. Because the signals occur on a millisecond timescale, translating to human decision-making using functional neuroimaging has been challenging. Previous neuroimaging work in humans has identified patterns of neural activity consistent with an accumulation account. However, the degree to which the accumulating neuroimaging signals reflect specific sources of perceptual evidence is unknown. Using an extended face/house discrimination task in conjunction with cognitive modeling, we tested whether accumulation signals, as measured using functional magnetic resonance imaging (fMRI), are stimulus-specific. Accumulation signals were defined as a change in the slope of the rising edge of activation corresponding with response time (RT), with higher slopes associated with faster RTs. Consistent with an accumulation account, fMRI activity in face- and house-selective regions in the inferior temporal cortex increased at a rate proportional to decision time in favor of the preferred stimulus. This finding indicates that stimulus-specific regions perform an evidence integrative function during goal-directed behavior and that different sources of evidence accumulate separately. We also assessed the decision-related function of other regions throughout the brain and found that several regions were consistent with classifications from prior work, suggesting a degree of domain generality in decision processing. Taken together, these results provide support for an integration-to-boundary decision mechanism and highlight possible roles of both domain-specific and domain-general regions in decision evidence evaluation. PMID:25562821

Does Size Matter? Atmospheric CO2 May Be a Stronger Driver of Stomatal Closing Rate Than Stomatal Size in Taxa That Diversified under Low CO2.

PubMed

Elliott-Kingston, Caroline; Haworth, Matthew; Yearsley, Jon M; Batke, Sven P; Lawson, Tracy; McElwain, Jennifer C

2016-01-01

One strategy for plants to optimize stomatal function is to open and close their stomata quickly in response to environmental signals. It is generally assumed that small stomata can alter aperture faster than large stomata. We tested the hypothesis that species with small stomata close faster than species with larger stomata in response to darkness by comparing rate of stomatal closure across an evolutionary range of species including ferns, cycads, conifers, and angiosperms under controlled ambient conditions (380 ppm CO2; 20.9% O2). The two species with fastest half-closure time and the two species with slowest half-closure time had large stomata while the remaining three species had small stomata, implying that closing rate was not correlated with stomatal size in these species. Neither was response time correlated with stomatal density, phylogeny, functional group, or life strategy. Our results suggest that past atmospheric CO2 concentration during time of taxa diversification may influence stomatal response time. We show that species which last diversified under low or declining atmospheric CO2 concentration close stomata faster than species that last diversified in a high CO2 world. Low atmospheric [CO2] during taxa diversification may have placed a selection pressure on plants to accelerate stomatal closing to maintain adequate internal CO2 and optimize water use efficiency.

Does Size Matter? Atmospheric CO2 May Be a Stronger Driver of Stomatal Closing Rate Than Stomatal Size in Taxa That Diversified under Low CO2

PubMed Central

Elliott-Kingston, Caroline; Haworth, Matthew; Yearsley, Jon M.; Batke, Sven P.; Lawson, Tracy; McElwain, Jennifer C.

2016-01-01

One strategy for plants to optimize stomatal function is to open and close their stomata quickly in response to environmental signals. It is generally assumed that small stomata can alter aperture faster than large stomata. We tested the hypothesis that species with small stomata close faster than species with larger stomata in response to darkness by comparing rate of stomatal closure across an evolutionary range of species including ferns, cycads, conifers, and angiosperms under controlled ambient conditions (380 ppm CO2; 20.9% O2). The two species with fastest half-closure time and the two species with slowest half-closure time had large stomata while the remaining three species had small stomata, implying that closing rate was not correlated with stomatal size in these species. Neither was response time correlated with stomatal density, phylogeny, functional group, or life strategy. Our results suggest that past atmospheric CO2 concentration during time of taxa diversification may influence stomatal response time. We show that species which last diversified under low or declining atmospheric CO2 concentration close stomata faster than species that last diversified in a high CO2 world. Low atmospheric [CO2] during taxa diversification may have placed a selection pressure on plants to accelerate stomatal closing to maintain adequate internal CO2 and optimize water use efficiency. PMID:27605929

Auditory and visual interhemispheric communication in musicians and non-musicians.

PubMed

Woelfle, Rebecca; Grahn, Jessica A

2013-01-01

The corpus callosum (CC) is a brain structure composed of axon fibres linking the right and left hemispheres. Musical training is associated with larger midsagittal cross-sectional area of the CC, suggesting that interhemispheric communication may be faster in musicians. Here we compared interhemispheric transmission times (ITTs) for musicians and non-musicians. ITT was measured by comparing simple reaction times to stimuli presented to the same hemisphere that controlled a button-press response (uncrossed reaction time), or to the contralateral hemisphere (crossed reaction time). Both visual and auditory stimuli were tested. We predicted that the crossed-uncrossed difference (CUD) for musicians would be smaller than for non-musicians as a result of faster interhemispheric transfer times. We did not expect a difference in CUDs between the visual and auditory modalities for either musicians or non-musicians, as previous work indicates that interhemispheric transfer may happen through the genu of the CC, which contains motor fibres rather than sensory fibres. There were no significant differences in CUDs between musicians and non-musicians. However, auditory CUDs were significantly smaller than visual CUDs. Although this auditory-visual difference was larger in musicians than non-musicians, the interaction between modality and musical training was not significant. Therefore, although musical training does not significantly affect ITT, the crossing of auditory information between hemispheres appears to be faster than visual information, perhaps because subcortical pathways play a greater role for auditory interhemispheric transfer.

Global, regional, and national levels of neonatal, infant, and under-5 mortality during 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

PubMed Central

Wang, Haidong; Liddell, Chelsea A; Coates, Matthew M; Mooney, Meghan D; Levitz, Carly E; Schumacher, Austin E; Apfel, Henry; Iannarone, Marissa; Phillips, Bryan; Lofgren, Katherine T; Sandar, Logan; Dorrington, Rob E; Rakovac, Ivo; Jacobs, Troy A; Liang, Xiaofeng; Zhou, Maigeng; Zhu, Jun; Yang, Gonghuan; Wang, Yanping; Liu, Shiwei; Li, Yichong; Ozgoren, Ayse Abbasoglu; Abera, Semaw Ferede; Abubakar, Ibrahim; Achoki, Tom; Adelekan, Ademola; Ademi, Zanfina; Alemu, Zewdie Aderaw; Allen, Peter J; AlMazroa, Mohammad AbdulAziz; Alvarez, Elena; Amankwaa, Adansi A; Amare, Azmeraw T; Ammar, Walid; Anwari, Palwasha; Cunningham, Solveig Argeseanu; Asad, Majed Masoud; Assadi, Reza; Banerjee, Amitava; Basu, Sanjay; Bedi, Neeraj; Bekele, Tolesa; Bell, Michelle L; Bhutta, Zulfiqar; Blore, Jed; Basara, Berrak Bora; Boufous, Soufiane; Breitborde, Nicholas; Bruce, Nigel G; Bui, Linh Ngoc; Carapetis, Jonathan R; Cárdenas, Rosario; Carpenter, David O; Caso, Valeria; Castro, Ruben Estanislao; Catalá-Lopéz, Ferrán; Cavlin, Alanur; Che, Xuan; Chiang, Peggy Pei-Chia; Chowdhury, Rajiv; Christophi, Costas A; Chuang, Ting-Wu; Cirillo, Massimo; Leite, Iuri da Costa; Courville, Karen J; Dandona, Lalit; Dandona, Rakhi; Davis, Adrian; Dayama, Anand; Deribe, Kebede; Dharmaratne, Samath D; Dherani, Mukesh K; Dilmen, Uğur; Ding, Eric L; Edmond, Karen M; Ermakov, Sergei Petrovich; Farzadfar, Farshad; Fereshtehnejad, Seyed-Mohammad; Fijabi, Daniel Obadare; Foigt, Nataliya; Forouzanfar, Mohammad H; Garcia, Ana C; Geleijnse, Johanna M; Gessner, Bradford D; Goginashvili, Ketevan; Gona, Philimon; Goto, Atsushi; Gouda, Hebe N; Green, Mark A; Greenwell, Karen Fern; Gugnani, Harish Chander; Gupta, Rahul; Hamadeh, Randah Ribhi; Hammami, Mouhanad; Harb, Hilda L; Hay, Simon; Hedayati, Mohammad T; Hosgood, H Dean; Hoy, Damian G; Idrisov, Bulat T; Islami, Farhad; Ismayilova, Samaya; Jha, Vivekanand; Jiang, Guohong; Jonas, Jost B; Juel, Knud; Kabagambe, Edmond Kato; Kazi, Dhruv S; Kengne, Andre Pascal; Kereselidze, Maia; Khader, Yousef Saleh; Khalifa, Shams Eldin Ali Hassan; Khang, Young-Ho; Kim, Daniel; Kinfu, Yohannes; Kinge, Jonas M; Kokubo, Yoshihiro; Kosen, Soewarta; Defo, Barthelemy Kuate; Kumar, G Anil; Kumar, Kaushalendra; Kumar, Ravi B; Lai, Taavi; Lan, Qing; Larsson, Anders; Lee, Jong-Tae; Leinsalu, Mall; Lim, Stephen S; Lipshultz, Steven E; Logroscino, Giancarlo; Lotufo, Paulo A; Lunevicius, Raimundas; Lyons, Ronan Anthony; Ma, Stefan; Mahdi, Abbas Ali; Marzan, Melvin Barrientos; Mashal, Mohammad Taufiq; Mazorodze, Tasara T; McGrath, John J; Memish, Ziad A; Mendoza, Walter; Mensah, George A; Meretoja, Atte; Miller, Ted R; Mills, Edward J; Mohammad, Karzan Abdulmuhsin; Mokdad, Ali H; Monasta, Lorenzo; Montico, Marcella; Moore, Ami R; Moschandreas, Joanna; Msemburi, William T; Mueller, Ulrich O; Muszynska, Magdalena M; Naghavi, Mohsen; Naidoo, Kovin S; Narayan, KM Venkat; Nejjari, Chakib; Ng, Marie; Ngirabega, Jean de Dieu; Nieuwenhuijsen, Mark J; Nyakarahuka, Luke; Ohkubo, Takayoshi; Omer, Saad B; Caicedo, Angel J Paternina; Wyk, Victoria Pillay-van; Pope, Dan; Prabhakaran, Dorairaj; Rahman, Sajjad UR; Rana, Saleem M; Reilly, Robert Quentin; Rojas-Rueda, David; Ronfani, Luca; Rushton, Lesley; Saeedi, Mohammad Yahya; Salomon, Joshua; Sampson, Uchechukwu; Santos, Itamar S; Sawhney, Monika; Schmidt, Jürgen C; Nazarova, Marina Shakh; She, Jun; Sheikhbahaei, Sara; Shibuya, Kenji; Shin, Hwashin Hyun; Shishani, Kawkab; Shiue, Ivy; Sigfusdottir, Inga Dora; Singh, Jasvinder A; Skirbekk, Vegard; Sliwa, Karen; Soshnikov, Sergey S; Sposato, Luciano A; Stathopoulou, Vasiliki Kalliopi; Stroumpoulis, Konstantinos; Tabb, Karen M; Talongwa, Roberto Tchio; Teixeira, Carolina Maria; Terkawi, Abdullah Sulieman; Thomson, Alan J; Lyman, Andrew L Thorne; Toyoshima, Hideaki; Dimbuene, Zacharie Tsala; Uwaliraye, Parfait; Uzun, Selen Begüm; Vasankari, Tommi J; Vasconcelos, Ana Maria Nogales; Vlassov, Vasiliy Victorovich; Vollset, Stein Emil; Vos, Theo; Waller, Stephen; Wan, Xia; Weichenthal, Scott; Weiderpass, Elisabete; Weintraub, Robert G; Westerman, Ronny; Wilkinson, James D; Williams, Hywel C; Yang, Yang C; Yentur, Gokalp Kadri; Yip, Paul; Yonemoto, Naohiro; Younis, Mustafa; Yu, Chuanhua; Jin, Kim Yun; Zaki, Maysaa El Sayed; Zhu, Shankuan; Lopez, Alan D; Murray, Christopher J L

2014-01-01

Summary Background Remarkable financial and political efforts have been focused on the reduction of child mortality during the past few decades. Timely measurements of levels and trends in under-5 mortality are important to assess progress towards the Millennium Development Goal 4 (MDG 4) target of reduction of child mortality by two thirds from 1990 to 2015, and to identify models of success. Methods We generated updated estimates of child mortality in early neonatal (age 0–6 days), late neonatal (7–28 days), postneonatal (29–364 days), childhood (1–4 years), and under-5 (0–4 years) age groups for 188 countries from 1970 to 2013, with more than 29 000 survey, census, vital registration, and sample registration datapoints. We used Gaussian process regression with adjustments for bias and non-sampling error to synthesise the data for under-5 mortality for each country, and a separate model to estimate mortality for more detailed age groups. We used explanatory mixed effects regression models to assess the association between under-5 mortality and income per person, maternal education, HIV child death rates, secular shifts, and other factors. To quantify the contribution of these different factors and birth numbers to the change in numbers of deaths in under-5 age groups from 1990 to 2013, we used Shapley decomposition. We used estimated rates of change between 2000 and 2013 to construct under-5 mortality rate scenarios out to 2030. Findings We estimated that 6·3 million (95% UI 6·0–6·6) children under-5 died in 2013, a 64% reduction from 17·6 million (17·1–18·1) in 1970. In 2013, child mortality rates ranged from 152·5 per 1000 livebirths (130·6–177·4) in Guinea-Bissau to 2·3 (1·8–2·9) per 1000 in Singapore. The annualised rates of change from 1990 to 2013 ranged from −6·8% to 0·1%. 99 of 188 countries, including 43 of 48 countries in sub-Saharan Africa, had faster decreases in child mortality during 2000–13 than during 1990–2000. In 2013, neonatal deaths accounted for 41·6% of under-5 deaths compared with 37·4% in 1990. Compared with 1990, in 2013, rising numbers of births, especially in sub-Saharan Africa, led to 1·4 million more child deaths, and rising income per person and maternal education led to 0·9 million and 2·2 million fewer deaths, respectively. Changes in secular trends led to 4·2 million fewer deaths. Unexplained factors accounted for only −1% of the change in child deaths. In 30 developing countries, decreases since 2000 have been faster than predicted attributable to income, education, and secular shift alone. Interpretation Only 27 developing countries are expected to achieve MDG 4. Decreases since 2000 in under-5 mortality rates are accelerating in many developing countries, especially in sub-Saharan Africa. The Millennium Declaration and increased development assistance for health might have been a factor in faster decreases in some developing countries. Without further accelerated progress, many countries in west and central Africa will still have high levels of under-5 mortality in 2030. Funding Bill & Melinda Gates Foundation, US Agency for International Development. PMID:24797572

Global, regional, and national levels of neonatal, infant, and under-5 mortality during 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013.

PubMed

Wang, Haidong; Liddell, Chelsea A; Coates, Matthew M; Mooney, Meghan D; Levitz, Carly E; Schumacher, Austin E; Apfel, Henry; Iannarone, Marissa; Phillips, Bryan; Lofgren, Katherine T; Sandar, Logan; Dorrington, Rob E; Rakovac, Ivo; Jacobs, Troy A; Liang, Xiaofeng; Zhou, Maigeng; Zhu, Jun; Yang, Gonghuan; Wang, Yanping; Liu, Shiwei; Li, Yichong; Ozgoren, Ayse Abbasoglu; Abera, Semaw Ferede; Abubakar, Ibrahim; Achoki, Tom; Adelekan, Ademola; Ademi, Zanfina; Alemu, Zewdie Aderaw; Allen, Peter J; AlMazroa, Mohammad AbdulAziz; Alvarez, Elena; Amankwaa, Adansi A; Amare, Azmeraw T; Ammar, Walid; Anwari, Palwasha; Cunningham, Solveig Argeseanu; Asad, Majed Masoud; Assadi, Reza; Banerjee, Amitava; Basu, Sanjay; Bedi, Neeraj; Bekele, Tolesa; Bell, Michelle L; Bhutta, Zulfiqar; Blore, Jed D; Basara, Berrak Bora; Boufous, Soufiane; Breitborde, Nicholas; Bruce, Nigel G; Bui, Linh Ngoc; Carapetis, Jonathan R; Cárdenas, Rosario; Carpenter, David O; Caso, Valeria; Castro, Ruben Estanislao; Catalá-Lopéz, Ferrán; Cavlin, Alanur; Che, Xuan; Chiang, Peggy Pei-Chia; Chowdhury, Rajiv; Christophi, Costas A; Chuang, Ting-Wu; Cirillo, Massimo; da Costa Leite, Iuri; Courville, Karen J; Dandona, Lalit; Dandona, Rakhi; Davis, Adrian; Dayama, Anand; Deribe, Kebede; Dharmaratne, Samath D; Dherani, Mukesh K; Dilmen, Uğur; Ding, Eric L; Edmond, Karen M; Ermakov, Sergei Petrovich; Farzadfar, Farshad; Fereshtehnejad, Seyed-Mohammad; Fijabi, Daniel Obadare; Foigt, Nataliya; Forouzanfar, Mohammad H; Garcia, Ana C; Geleijnse, Johanna M; Gessner, Bradford D; Goginashvili, Ketevan; Gona, Philimon; Goto, Atsushi; Gouda, Hebe N; Green, Mark A; Greenwell, Karen Fern; Gugnani, Harish Chander; Gupta, Rahul; Hamadeh, Randah Ribhi; Hammami, Mouhanad; Harb, Hilda L; Hay, Simon; Hedayati, Mohammad T; Hosgood, H Dean; Hoy, Damian G; Idrisov, Bulat T; Islami, Farhad; Ismayilova, Samaya; Jha, Vivekanand; Jiang, Guohong; Jonas, Jost B; Juel, Knud; Kabagambe, Edmond Kato; Kazi, Dhruv S; Kengne, Andre Pascal; Kereselidze, Maia; Khader, Yousef Saleh; Khalifa, Shams Eldin Ali Hassan; Khang, Young-Ho; Kim, Daniel; Kinfu, Yohannes; Kinge, Jonas M; Kokubo, Yoshihiro; Kosen, Soewarta; Defo, Barthelemy Kuate; Kumar, G Anil; Kumar, Kaushalendra; Kumar, Ravi B; Lai, Taavi; Lan, Qing; Larsson, Anders; Lee, Jong-Tae; Leinsalu, Mall; Lim, Stephen S; Lipshultz, Steven E; Logroscino, Giancarlo; Lotufo, Paulo A; Lunevicius, Raimundas; Lyons, Ronan Anthony; Ma, Stefan; Mahdi, Abbas Ali; Marzan, Melvin Barrientos; Mashal, Mohammad Taufiq; Mazorodze, Tasara T; McGrath, John J; Memish, Ziad A; Mendoza, Walter; Mensah, George A; Meretoja, Atte; Miller, Ted R; Mills, Edward J; Mohammad, Karzan Abdulmuhsin; Mokdad, Ali H; Monasta, Lorenzo; Montico, Marcella; Moore, Ami R; Moschandreas, Joanna; Msemburi, William T; Mueller, Ulrich O; Muszynska, Magdalena M; Naghavi, Mohsen; Naidoo, Kovin S; Narayan, K M Venkat; Nejjari, Chakib; Ng, Marie; de Dieu Ngirabega, Jean; Nieuwenhuijsen, Mark J; Nyakarahuka, Luke; Ohkubo, Takayoshi; Omer, Saad B; Caicedo, Angel J Paternina; Pillay-van Wyk, Victoria; Pope, Dan; Pourmalek, Farshad; Prabhakaran, Dorairaj; Rahman, Sajjad U R; Rana, Saleem M; Reilly, Robert Quentin; Rojas-Rueda, David; Ronfani, Luca; Rushton, Lesley; Saeedi, Mohammad Yahya; Salomon, Joshua A; Sampson, Uchechukwu; Santos, Itamar S; Sawhney, Monika; Schmidt, Jürgen C; Shakh-Nazarova, Marina; She, Jun; Sheikhbahaei, Sara; Shibuya, Kenji; Shin, Hwashin Hyun; Shishani, Kawkab; Shiue, Ivy; Sigfusdottir, Inga Dora; Singh, Jasvinder A; Skirbekk, Vegard; Sliwa, Karen; Soshnikov, Sergey S; Sposato, Luciano A; Stathopoulou, Vasiliki Kalliopi; Stroumpoulis, Konstantinos; Tabb, Karen M; Talongwa, Roberto Tchio; Teixeira, Carolina Maria; Terkawi, Abdullah Sulieman; Thomson, Alan J; Thorne-Lyman, Andrew L; Toyoshima, Hideaki; Dimbuene, Zacharie Tsala; Uwaliraye, Parfait; Uzun, Selen Begüm; Vasankari, Tommi J; Vasconcelos, Ana Maria Nogales; Vlassov, Vasiliy Victorovich; Vollset, Stein Emil; Waller, Stephen; Wan, Xia; Weichenthal, Scott; Weiderpass, Elisabete; Weintraub, Robert G; Westerman, Ronny; Wilkinson, James D; Williams, Hywel C; Yang, Yang C; Yentur, Gokalp Kadri; Yip, Paul; Yonemoto, Naohiro; Younis, Mustafa; Yu, Chuanhua; Jin, Kim Yun; El Sayed Zaki, Maysaa; Zhu, Shankuan; Vos, Theo; Lopez, Alan D; Murray, Christopher J L

2014-09-13

Remarkable financial and political efforts have been focused on the reduction of child mortality during the past few decades. Timely measurements of levels and trends in under-5 mortality are important to assess progress towards the Millennium Development Goal 4 (MDG 4) target of reduction of child mortality by two thirds from 1990 to 2015, and to identify models of success. We generated updated estimates of child mortality in early neonatal (age 0-6 days), late neonatal (7-28 days), postneonatal (29-364 days), childhood (1-4 years), and under-5 (0-4 years) age groups for 188 countries from 1970 to 2013, with more than 29,000 survey, census, vital registration, and sample registration datapoints. We used Gaussian process regression with adjustments for bias and non-sampling error to synthesise the data for under-5 mortality for each country, and a separate model to estimate mortality for more detailed age groups. We used explanatory mixed effects regression models to assess the association between under-5 mortality and income per person, maternal education, HIV child death rates, secular shifts, and other factors. To quantify the contribution of these different factors and birth numbers to the change in numbers of deaths in under-5 age groups from 1990 to 2013, we used Shapley decomposition. We used estimated rates of change between 2000 and 2013 to construct under-5 mortality rate scenarios out to 2030. We estimated that 6·3 million (95% UI 6·0-6·6) children under-5 died in 2013, a 64% reduction from 17·6 million (17·1-18·1) in 1970. In 2013, child mortality rates ranged from 152·5 per 1000 livebirths (130·6-177·4) in Guinea-Bissau to 2·3 (1·8-2·9) per 1000 in Singapore. The annualised rates of change from 1990 to 2013 ranged from -6·8% to 0·1%. 99 of 188 countries, including 43 of 48 countries in sub-Saharan Africa, had faster decreases in child mortality during 2000-13 than during 1990-2000. In 2013, neonatal deaths accounted for 41·6% of under-5 deaths compared with 37·4% in 1990. Compared with 1990, in 2013, rising numbers of births, especially in sub-Saharan Africa, led to 1·4 million more child deaths, and rising income per person and maternal education led to 0·9 million and 2·2 million fewer deaths, respectively. Changes in secular trends led to 4·2 million fewer deaths. Unexplained factors accounted for only -1% of the change in child deaths. In 30 developing countries, decreases since 2000 have been faster than predicted attributable to income, education, and secular shift alone. Only 27 developing countries are expected to achieve MDG 4. Decreases since 2000 in under-5 mortality rates are accelerating in many developing countries, especially in sub-Saharan Africa. The Millennium Declaration and increased development assistance for health might have been a factor in faster decreases in some developing countries. Without further accelerated progress, many countries in west and central Africa will still have high levels of under-5 mortality in 2030. Bill & Melinda Gates Foundation, US Agency for International Development. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cycle Time Reduction in Trapped Mercury Ion Atomic Frequency Standards

NASA Technical Reports Server (NTRS)

Burt, Eric A.; Tjoelker, Robert L.; Taghavi, Shervin

2011-01-01

The use of the mercury ion isotope (201)Hg(+) was examined for an atomic clock. Taking advantage of the faster optical pumping time in (201)Hg(+) reduces both the state preparation and the state readout times, thereby decreasing the overall cycle time of the clock and reducing the impact of medium-term LO noise on the performance of the frequency standard. The spectral overlap between the plasma discharge lamp used for (201)Hg(+) state preparation and readout is much larger than that of the lamp used for the more conventional (199)Hg(+). There has been little study of (201)Hg(+) for clock applications (in fact, all trapped ion clock work in mercury has been with (199)Hg(+); however, recently the optical pumping time in (201)Hg(+) has been measured and found to be 0.45 second, or about three times faster than in (199)Hg(+) due largely to the better spectral overlap. This can be used to reduce the overall clock cycle time by over 2 seconds, or up to a factor of 2 improvement. The use of the (201)Hg(+) for an atomic clock is totally new. Most attempts to reduce the impact of LO noise have focused on reducing the interrogation time. In the trapped ion frequency standards built so far at JPL, the optical pumping time is already at its minimum so that no enhancement can be had by shortening it. However, by using (201)Hg(+), this is no longer the case. Furthermore, integrity monitoring, the mechanism that determines whether the clock is functioning normally, cannot happen faster than the clock cycle time. Therefore, a shorter cycle time will enable quicker detection of failure modes and recovery from them.

Comment [on “Sea level rise shown to drive coastal erosion”

USGS Publications Warehouse

Pilkey, Orrin H.; Young, Robert S.; Bush, David M.

2000-01-01

Leatherman et al. [2000] (Eos, Trans., AGU, February 8, 2000, p.55) affirm that global eustatic sea-level rise is driving coastal erosion. Furthermore, they argue that the long-term average rate of shoreline retreat is 150 times the rate of sea-level rise. This rate, they say, is more than a magnitude greater than would be expected from a simple response to sea-level rise through inundation of the shoreline. We agree that sea-level rise is the primary factor causing shoreline retreat in stable coastal areas.This is intuitive. We also believe, however, that the Leatherman et al. [2000] study has greatly underestimated the rate of coastal recession along most low slope shorelines. Slopes along the North Carolina continental shelf/coastal plain approach 10,000:1. To us, this suggests that we should expect rates of shoreline recession 10,000 times the rate of sea-level rise through simple inundation of the shoreline.

Raman spectroscopic approach to monitor the in vitro cyclization of creatine → creatinine

NASA Astrophysics Data System (ADS)

Gangopadhyay, Debraj; Sharma, Poornima; Singh, Sachin Kumar; Singh, Pushkar; Tarcea, Nicolae; Deckert, Volker; Popp, Jürgen; Singh, Ranjan K.

2015-01-01

The creatine → creatinine cyclization, an important metabolic phenomenon has been initiated in vitro at acidic pH and studied through Raman spectroscopic and DFT approach. The equilibrium composition of neutral, zwitterionic and protonated microspecies of creatine has been monitored with time as the reaction proceeds. Time series Raman spectra show clear signature of creatinine formation at pH 3 after ∼240 min at room temperature and reaction is faster at higher temperature. The spectra at pH 1 and pH 5 do not show such signature up to 270 min implying faster reaction rate at pH 3.

Efficient solution of the simplified P N equations

DOE PAGES

Hamilton, Steven P.; Evans, Thomas M.

2014-12-23

We show new solver strategies for the multigroup SPN equations for nuclear reactor analysis. By forming the complete matrix over space, moments, and energy a robust set of solution strategies may be applied. Moreover, power iteration, shifted power iteration, Rayleigh quotient iteration, Arnoldi's method, and a generalized Davidson method, each using algebraic and physics-based multigrid preconditioners, have been compared on C5G7 MOX test problem as well as an operational PWR model. These results show that the most ecient approach is the generalized Davidson method, that is 30-40 times faster than traditional power iteration and 6-10 times faster than Arnoldi's method.

Transferring ecosystem simulation codes to supercomputers

NASA Technical Reports Server (NTRS)

Skiles, J. W.; Schulbach, C. H.

1995-01-01

Many ecosystem simulation computer codes have been developed in the last twenty-five years. This development took place initially on main-frame computers, then mini-computers, and more recently, on micro-computers and workstations. Supercomputing platforms (both parallel and distributed systems) have been largely unused, however, because of the perceived difficulty in accessing and using the machines. Also, significant differences in the system architectures of sequential, scalar computers and parallel and/or vector supercomputers must be considered. We have transferred a grassland simulation model (developed on a VAX) to a Cray Y-MP/C90. We describe porting the model to the Cray and the changes we made to exploit the parallelism in the application and improve code execution. The Cray executed the model 30 times faster than the VAX and 10 times faster than a Unix workstation. We achieved an additional speedup of 30 percent by using the compiler's vectoring and 'in-line' capabilities. The code runs at only about 5 percent of the Cray's peak speed because it ineffectively uses the vector and parallel processing capabilities of the Cray. We expect that by restructuring the code, it could execute an additional six to ten times faster.

When Movies Matter: Exposure to Smoking in Movies and Changes in Smoking Behavior

PubMed Central

Dal Cin, Sonya; Stoolmiller, Mike; Sargent, James D.

2011-01-01

The authors investigated the association between exposure to smoking in movies and the initiation and progression of adolescent smoking over time among 6,522 U.S. adolescents (between the ages of 10 and 14 years, at baseline) in a nationally representative, 4-wave random-digit-dial telephone survey. They conducted a hazard (survival) analysis testing whether exposure to movie smoking and demographic, personality, social, and structural factors predict (a) earlier smoking onset and (b) faster transition to experimental (1–99 cigarettes/lifetime) and established smoking (>100 cigarettes/lifetime). Results suggest that higher exposure to movie smoking is associated with less time to trying cigarettes for the first time (adjusted hazard ratio = 1.66; 95% CI [1.37, 2.01]) but not with faster escalation of smoking behavior following initiation (adjusted hazard ratio = 1.53; 95% CI [0.84, 2.79]). In contrast, age, peer smoking, parenting style, and availability of cigarettes in the home were predictors of earlier onset and faster transition to established smoking. Thus, the authors concluded that the effect of exposure to mass-mediated images of smoking in movies may decline once adolescents have started to smoke, whereas peers and access to tobacco remain influential. PMID:22085232

When movies matter: exposure to smoking in movies and changes in smoking behavior.

PubMed

Dal Cin, Sonya; Stoolmiller, Mike; Sargent, James D

2012-01-01

The authors investigated the association between exposure to smoking in movies and the initiation and progression of adolescent smoking over time among 6,522 U.S. adolescents (between the ages of 10 and 14 years, at baseline) in a nationally representative, 4-wave random-digit-dial telephone survey. They conducted a hazard (survival) analysis testing whether exposure to movie smoking and demographic, personality, social, and structural factors predict (a) earlier smoking onset and (b) faster transition to experimental (1-99 cigarettes/lifetime) and established smoking (>100 cigarettes/lifetime). Results suggest that higher exposure to movie smoking is associated with less time to trying cigarettes for the first time (adjusted hazard ratio = 1.66; 95% CI [1.37, 2.01]) but not with faster escalation of smoking behavior following initiation (adjusted hazard ratio = 1.53; 95% CI [0.84, 2.79]). In contrast, age, peer smoking, parenting style, and availability of cigarettes in the home were predictors of earlier onset and faster transition to established smoking. Thus, the authors concluded that the effect of exposure to mass-mediated images of smoking in movies may decline once adolescents have started to smoke, whereas peers and access to tobacco remain influential.

Dynamically programmable cache

NASA Astrophysics Data System (ADS)

Nakkar, Mouna; Harding, John A.; Schwartz, David A.; Franzon, Paul D.; Conte, Thomas

1998-10-01

Reconfigurable machines have recently been used as co- processors to accelerate the execution of certain algorithms or program subroutines. The problems with the above approach include high reconfiguration time and limited partial reconfiguration. By far the most critical problems are: (1) the small on-chip memory which results in slower execution time, and (2) small FPGA areas that cannot implement large subroutines. Dynamically Programmable Cache (DPC) is a novel architecture for embedded processors which offers solutions to the above problems. To solve memory access problems, DPC processors merge reconfigurable arrays with the data cache at various cache levels to create a multi-level reconfigurable machines. As a result DPC machines have both higher data accessibility and FPGA memory bandwidth. To solve the limited FPGA resource problem, DPC processors implemented multi-context switching (Virtualization) concept. Virtualization allows implementation of large subroutines with fewer FPGA cells. Additionally, DPC processors can parallelize the execution of several operations resulting in faster execution time. In this paper, the speedup improvement for DPC machines are shown to be 5X faster than an Altera FLEX10K FPGA chip and 2X faster than a Sun Ultral SPARC station for two different algorithms (convolution and motion estimation).

Statistical aspects of solar flares

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

1987-01-01

A survey of the statistical properties of 850 H alpha solar flares during 1975 is presented. Comparison of the results found here with those reported elsewhere for different epochs is accomplished. Distributions of rise time, decay time, and duration are given, as are the mean, mode, median, and 90th percentile values. Proportions by selected groupings are also determined. For flares in general, mean values for rise time, decay time, and duration are 5.2 + or - 0.4 min, and 18.1 + or 1.1 min, respectively. Subflares, accounting for nearly 90 percent of the flares, had mean values lower than those found for flares of H alpha importance greater than 1, and the differences are statistically significant. Likewise, flares of bright and normal relative brightness have mean values of decay time and duration that are significantly longer than those computed for faint flares, and mass-motion related flares are significantly longer than non-mass-motion related flares. Seventy-three percent of the mass-motion related flares are categorized as being a two-ribbon flare and/or being accompanied by a high-speed dark filament. Slow rise time flares (rise time greater than 5 min) have a mean value for duration that is significantly longer than that computed for fast rise time flares, and long-lived duration flares (duration greater than 18 min) have a mean value for rise time that is significantly longer than that computed for short-lived duration flares, suggesting a positive linear relationship between rise time and duration for flares. Monthly occurrence rates for flares in general and by group are found to be linearly related in a positive sense to monthly sunspot number. Statistical testing reveals the association between sunspot number and numbers of flares to be significant at the 95 percent level of confidence, and the t statistic for slope is significant at greater than 99 percent level of confidence. Dependent upon the specific fit, between 58 percent and 94 percent of the variation can be accounted for with the linear fits. A statistically significant Northern Hemisphere flare excess (P less than 1 percent) was found, as was a Western Hemisphere excess (P approx 3 percent). Subflares were more prolific within 45 deg of central meridian (P less than 1 percent), while flares of H alpha importance or = 1 were more prolific near the limbs greater than 45 deg from central meridian; P approx 2 percent). Two-ribbon flares were more frequent within 45 deg of central meridian (P less than 1 percent). Slow rise time flares occurred more frequently in the western hemisphere (P approx 2 percent), as did short-lived duration flares (P approx 9 percent), but fast rise time flares were not preferentially distributed (in terms of east-west or limb-disk). Long-lived duration flares occurred more often within 45 deg 0 central meridian (P approx 7 percent). Mean durations for subflares and flares of H alpha importance or + 1, found within 45 deg of central meridian, are 14 percent and 70 percent, respectively, longer than those found for flares closer to the limb. As compared to flares occurring near cycle maximum, the flares of 1975 (near solar minimum) have mean values of rise time, decay time, and duration that are significantly shorter. A flare near solar maximum, on average, is about 1.6 times longer than one occurring near solar minimum.

Temporal properties of the myopic response to defocus in the guinea pig.

PubMed

Leotta, Amelia J; Bowrey, Hannah E; Zeng, Guang; McFadden, Sally A

2013-05-01

Hyperopic defocus induces myopia in all species tested and is believed to underlie the progression of human myopia. We determined the temporal properties of the effects of hyperopic defocus in a mammalian eye. In Experiment 1, the rise and decay time of the responses elicited by hyperopic defocus were calculated in 111 guinea pigs by giving repeated episodes of monocular -4 D lens wear (from 5 to 6 days of age for 12 days) interspersed with various dark intervals. In Experiment 2, the decay time constant was calculated in 152 guinea pigs when repeated periods of monocular -5 D lens-wear (from 4 days of age for 7 days) were interrupted with free viewing periods of different lengths. At the end of the lens-wear period, ocular parameters were measured and time constants were calculated relative to the maximum response induced by continuous lens wear. When hyperopic defocus was experienced with dark intervals between episodes, the time required to induce 50% of the maximum achievable myopia and ocular elongation was at most 30 min. Saturated 1 h episodes took at least 22 h for refractive error and 31 h for ocular length, to decay to 50% of the maximum response. However, the decay was an order of magnitude faster when hyperopic defocus episodes were interrupted with a daily free viewing period, with only 36 min required to reduce relative myopia and ocular elongation by 50%. Hyperopic defocus causes myopia with brief exposures and is very long lasting in the absence of competing signals. However, this myopic response rapidly decays if interrupted by periods of 'normal viewing' at least 30 min in length, wherein ocular growth appears to be guided preferentially by the least amount of hyperopic defocus experienced. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

Phase transition of charged-AdS black holes and quasinormal modes: A time domain analysis

NASA Astrophysics Data System (ADS)

Chabab, M.; El Moumni, H.; Iraoui, S.; Masmar, K.

2017-10-01

In this work, we investigate the time evolution of a massless scalar perturbation around small and large RN-AdS4 black holes for the purpose of probing the thermodynamic phase transition. We show that below the critical point the scalar perturbation decays faster with increasing of the black hole size, both for small and large black hole phases. Our analysis of the time profile of quasinormal mode reveals a sharp distinction between the behaviors of both phases, providing a reliable tool to probe the black hole phase transition. However at the critical point P=Pc, as the black hole size extends, we note that the damping time increases and the perturbation decays faster, the oscillation frequencies raise either in small and large black hole phase. In this case the time evolution approach fails to track the AdS4 black hole phase.

Rise-Time of FRET-Acceptor Fluorescence Tracks Protein Folding

PubMed Central

Lindhoud, Simon; Westphal, Adrie H.; van Mierlo, Carlo P. M.; Visser, Antonie J. W. G.; Borst, Jan Willem

2014-01-01

Uniform labeling of proteins with fluorescent donor and acceptor dyes with an equimolar ratio is paramount for accurate determination of Förster resonance energy transfer (FRET) efficiencies. In practice, however, the labeled protein population contains donor-labeled molecules that have no corresponding acceptor. These FRET-inactive donors contaminate the donor fluorescence signal, which leads to underestimation of FRET efficiencies in conventional fluorescence intensity and lifetime-based FRET experiments. Such contamination is avoided if FRET efficiencies are extracted from the rise time of acceptor fluorescence upon donor excitation. The reciprocal value of the rise time of acceptor fluorescence is equal to the decay rate of the FRET-active donor fluorescence. Here, we have determined rise times of sensitized acceptor fluorescence to study the folding of double-labeled apoflavodoxin molecules and show that this approach tracks the characteristics of apoflavodoxinʼs complex folding pathway. PMID:25535076

Preliminary results from the White Sands Missile Range sonic boom propagation experiment

NASA Technical Reports Server (NTRS)

Willshire, William L., Jr.; Devilbiss, David W.

1992-01-01

Sonic boom bow shock amplitude and rise time statistics from a recent sonic boom propagation experiment are presented. Distributions of bow shock overpressure and rise time measured under different atmospheric turbulence conditions for the same test aircraft are quite different. The peak overpressure distributions are skewed positively, indicating a tendency for positive deviations from the mean to be larger than negative deviations. Standard deviations of overpressure distributions measured under moderate turbulence were 40 percent larger than those measured under low turbulence. As turbulence increased, the difference between the median and the mean increased, indicating increased positive overpressure deviations. The effect of turbulence was more readily seen in the rise time distributions. Under moderate turbulence conditions, the rise time distribution means were larger by a factor of 4 and the standard deviations were larger by a factor of 3 from the low turbulence values. These distribution changes resulted in a transition from a peaked appearance of the rise time distribution for the morning to a flattened appearance for the afternoon rise time distributions. The sonic boom propagation experiment consisted of flying three types of aircraft supersonically over a ground-based microphone array with concurrent measurements of turbulence and other meteorological data. The test aircraft were a T-38, an F-15, and an F-111, and they were flown at speeds of Mach 1.2 to 1.3, 30,000 feet above a 16 element, linear microphone array with an inter-element spacing of 200 ft. In two weeks of testing, 57 supersonic passes of the test aircraft were flown from early morning to late afternoon.

Changes in Choice Reaction Time During and After 8 Days Exhaustive Cycling Are Not Related to Changes in Physical Performance.

PubMed

Ten Haaf, Twan; van Staveren, Selma; Iannetta, Danilo; Roelands, Bart; Meeusen, Romain; Piacentini, Maria F; Foster, Carl; Koenderman, Leo; Daanen, Hein A M; de Koning, Jos J

2018-04-01

Reaction time has been proposed as a training monitoring tool, but to date, results are equivocal. Therefore, it was investigated whether reaction time can be used as a monitoring tool to establish overreaching. The study included 30 subjects (11 females and 19 males, age: 40.8 [10.8] years, VO 2max : 51.8 [6.3] mL/kg/min) who participated in an 8-day cycling event. The external exercise load increased approximately 900% compared with the preparation period. Performance was measured before and after the event using a maximal incremental cycling test. Subjects with decreased performance after the event were classified as functionally overreached (FOR) and others as acutely fatigued (AF). A choice reaction time test was performed 2 weeks before (pre), 1 week after (post), and 5 weeks after (follow-up), as well as at the start and end of the event. A total of 14 subjects were classified as AF and 14 as FOR (2 subjects were excluded). During the event, reaction time at the end was 68 ms (95% confidence interval, 46-89) faster than at the start. Reaction time post event was 41 ms (95% confidence interval, 12-71) faster than pre event and follow-up was 55 ms faster (95% confidence interval, 26-83). The time by class interaction was not significant during (P = .26) and after (P = .43) the event. Correlations between physical performance and reaction time were not significant (all Ps > .30). No differences in choice reaction time between AF and FOR subjects were observed. It is suggested that choice reaction time is not valid for early detection of overreaching in the field.

Media use as a reason for meal skipping and fast eating in secondary school children.

PubMed

Van den Bulck, J; Eggermont, S

2006-04-01

This study examined self-reported meal skipping and eating faster than usual with the goal of watching television or playing computer games. Respondents reported their media use and indicated how often they skipped a meal to watch a favourite television programme or to play a computer game, and how often they ate faster than usual in order to watch television or play a computer game. Respondents were 2546 adolescents of 13 (first year of secondary school) and 16 years (fourth year of secondary school) of age. About one respondent in 10 skipped at least one meal every week for either television viewing or computer game playing. Weekly meal skipping for television viewing occurs more regularly in boys and first-year students, but particularly in teenagers who view 5 h or more daily (15% of the sample). The category of teenagers who play computer games four times a week or more (25.3% of the sample) is at increased risk of meal skipping; those who play more than four times a week are 10 times more likely weekly to skip a meal. A quarter of the adolescents eat faster at least once a week to be able to watch television or play a computer game. Regardless of gender and school year, teenagers' risk of eating faster progressively increases with their use of the media. Those who watch 4 h or more daily are about seven times more likely to skip a meal for television and those who play computer games at least four times a week are nine times more likely weekly to skip a meal. Unhealthy eating habits can be a side effect of heavy or excessive media use. Teenagers' use of television or game computers during nonworking or out-of-school hours partly displaces the amount of time that needs to be spent at meals. Practitioners and educators may try to encourage or restore a pattern of healthful meal consumption habits by reducing the amount of media use, and by supporting parental rule-making regarding children's eating habits and media use.

High Fidelity, “Faster than Real-Time” Simulator for Predicting Power System Dynamic Behavior - Final Technical Report

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

Flueck, Alex

The “High Fidelity, Faster than Real­Time Simulator for Predicting Power System Dynamic Behavior” was designed and developed by Illinois Institute of Technology with critical contributions from Electrocon International, Argonne National Laboratory, Alstom Grid and McCoy Energy. Also essential to the project were our two utility partners: Commonwealth Edison and AltaLink. The project was a success due to several major breakthroughs in the area of large­scale power system dynamics simulation, including (1) a validated faster than real­ time simulation of both stable and unstable transient dynamics in a large­scale positive sequence transmission grid model, (2) a three­phase unbalanced simulation platform formore » modeling new grid devices, such as independently controlled single­phase static var compensators (SVCs), (3) the world’s first high fidelity three­phase unbalanced dynamics and protection simulator based on Electrocon’s CAPE program, and (4) a first­of­its­ kind implementation of a single­phase induction motor model with stall capability. The simulator results will aid power grid operators in their true time of need, when there is a significant risk of cascading outages. The simulator will accelerate performance and enhance accuracy of dynamics simulations, enabling operators to maintain reliability and steer clear of blackouts. In the long­term, the simulator will form the backbone of the newly conceived hybrid real­time protection and control architecture that will coordinate local controls, wide­area measurements, wide­area controls and advanced real­time prediction capabilities. The nation’s citizens will benefit in several ways, including (1) less down time from power outages due to the faster­than­real­time simulator’s predictive capability, (2) higher levels of reliability due to the detailed dynamics plus protection simulation capability, and (3) more resiliency due to the three­ phase unbalanced simulator’s ability to model three­phase and single­ phase networks and devices.« less

Swim drink study: a randomised controlled trial of during-exercise rehydration and swimming performance.

PubMed

Briars, Graham L; Gordon, Gillian Suzanne; Lawrence, Andrew; Turner, Andrew; Perry, Sharon; Pillbrow, Dan; Walston, Florence Einstein; Molyneux, Paul

2017-01-01

To determine whether during-exercise rehydration improves swimming performance and whether sports drink or water have differential effects on performance. Randomised controlled multiple crossover trial. A UK competitive swimming club. 19 club-level competitive swimmers, median age (range) 13 (11-17) years. Subjects were scheduled to drink ad libitum commercial isotonic sports drink (3.9 g sugars and 0.13 g salt per 100 mL) or water (three sessions each) or no drink (six sessions) in the course of twelve 75 min training sessions, each of which was followed by a 30 min test set of ten 100 m maximum-effort freestyle sprints each starting at 3 min intervals. Times for the middle 50 m of each sprint measured using electronic timing equipment in a Federation Internationale de Natation (FINA)-compliant six-lane 25 m competition swimming pool. Software-generated individual random session order in sealed envelopes. Analysis subset of eight sessions randomly selected by software after data collection completed. Participants blind to drink allocation until session start. In the analysis data set of 1118 swims, there was no significant difference between swim times for drinking and not drinking nor between drinking water or a sports drink. Mean (SEM) 50 m time for no-drink swims was 38.077 (0.128) s and 38.105 (0.131) s for drink swims, p=0.701. Mean 50 m times were 38.031 (0.184) s for drinking sports drink and 38.182 (0.186) s for drinking water, p=0.073. Times after not drinking were 0.027 s faster than after drinking (95% CI 0.186 s faster to 0.113 s slower). Times after drinking sports drink were 0.151 s faster than after water (95% CI 0.309 s faster to 0.002 s slower). Mean (SEM) dehydration from exercise was 0.42 (0.11)%. Drinking water or sports drink over 105 min of sustained effort swimming training does not improve swimming performance. ISRCTN: 49860006.

Effect of reaction time on the formation of disinfection byproducts

USGS Publications Warehouse

Rathbun, R.E.

1997-01-01

The effect of reaction time on the trihalomethane and nonpurgeable total organic-halide formation potentials was determined by chlorinating water samples from the Mississippi, Missouri, and Ohio Rivers. Samples were collected for three seasons at 12 locations on the Mississippi from Minneapolis, Minnesota, to New Orleans, Louisiana, and on the Missouri and Ohio 1.6 kilometers above their confluences with the Mississippi. Both types of compounds formed rapidly during the initial stages of the reaction-time period, with formation rates decreasing with time. The ratio of the nonpurgeable total organic-halide and trihalomethane concentrations decreased with time, with the nonpurgeable total organic-halide compounds forming faster during the first stages of the time period and the trihalomethane compounds forming faster during the latter stages of the time period. Variation with distance along the Mississippi River of the formation rates approximately paralleled the variation of the dissolved organic carbon concentration, indicating that the rates of formation, as well as the concentrations of the compounds formed, depended on the dissolved organic carbon concentration.

Gravitational salt tectonics above a rising basement plateau offshore Algeria

NASA Astrophysics Data System (ADS)

Gaullier, Virginie; Vendeville, Bruno C.; Besème, Grégoire; Legoux, Gaetan; Déverchère, Jacques; Lymer, Gaël

2017-04-01

Seismic data (survey "MARADJA 1", 2003) offshore the Algerian coast have imaged an unexpected deformation pattern of the Messinian salt (Mobile Unit; MU) and its sedimentary overburden (Messinian Upper Unit and Plio-Quaternary) above an actively rising plateau in the subsalt basement. From a geodynamic point of view, the region is undergoing crustal convergence, as attested by the Boumerdes earthquake (2003, magnitude 6.8). The rise of this plateau, forming a 3D promontory restricted to the area offshore Algiers, is associated with that geodynamic setting. The seismic profiles show several subsalt thrusts (Domzig et al. 2006). The data provided additional information on the deformation of the Messinian mobile evaporitic unit and its Plio-Quaternary overburden. Margin-perpendicular profiles show mostly compressional features (anticlines and synclines) that had little activity during Messinian times, then grew more during Plio-Quaternary times. A few normal faults are also present, but are not accompanied by salt rise. By contrast, margin-parallel profiles clearly show that extensional, reactive salt diapiric ridges (symptomatic with their triangular shape in cross section) formed early, as early as the time of deposition of the Messinian Upper Unit, as recorded by fan-shaped strata. These ridges have recorded E-W, thin-skinned gravity gliding above the Messinian salt, as a response to the rise of the basement plateau. We tested this hypothesis using two analogue models, one where we assumed that the rise of the plateau started after Messinian times (initially tabular salt across the entire region), the second model assumed that the plateau had already risen partially as the Messininan Mobile Unit was deposited (salt initially thinner above the plateau than in the adjacent regions). In both experiments, the rise of the plateau generated preferential E-W extension above the salt, combined with N-S shortening. Extension was caused by gravity gliding of the salt from above the rising basement toward the deeper adjacent basins. So far, the deformation pattern of the salt and overburden on the plateau did not allow us to use it as a clear indicator of whether the plateau's rise started before or during Messinian times.

Solution-processed PCDTBT capped low-voltage InGaZnO{sub x} thin film phototransistors for visible-light detection

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

Wang, Han; Xiao, Yubin; Chen, Zefeng

The effects of visible-light detection based on solution processed poly[N-9′′-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′, 3′benzothiadiazole) (PCDTBT) capped InGaZnOx (IGZO) phototransistors with Al{sub 2}O{sub x} serving as gate dielectric are investigated in this paper. The high-k dielectric is used to lower the device operating voltage down to 2 V. Photons emitted from laser sources with the wavelengths (λ) of 532 nm and 635 nm are absorbed through the layer of PCDTBT to generate electron-hole-pairs (EHPs). After the separation of EHPs, electrons are injected into IGZO layer through the p-n junction formed between the IGZO (n-type semiconductor) and the PCDTBT (p-type semiconductor). The photo-generated carriers boost the drain currentmore » of the transistors as well as bring about the negative threshold voltage shift. Significant enhanced detection performance is achieved under the laser wavelength of 532 nm. The highest photoresponsivity reaches up to 20 A/W, while the photoresponse rise time comes to 10 ms and the fall time comes to approximate 76 ms, which is much faster than trap assisted IGZO visible light detection. The fabricated phototransistors favor the application of visible-light detectors and/or optical switches.« less

Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

NASA Astrophysics Data System (ADS)

Batterman, Sarah A.; Hedin, Lars O.; van Breugel, Michiel; Ransijn, Johannes; Craven, Dylan J.; Hall, Jefferson S.

2013-10-01

Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2), but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000kg carbon per hectare) in the first 12years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2.

Key role of symbiotic dinitrogen fixation in tropical forest secondary succession.

PubMed

Batterman, Sarah A; Hedin, Lars O; van Breugel, Michiel; Ransijn, Johannes; Craven, Dylan J; Hall, Jefferson S

2013-10-10

Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2), but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000 kg carbon per hectare) in the first 12 years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2.

Second-generation PLINK: rising to the challenge of larger and richer datasets.

PubMed

Chang, Christopher C; Chow, Carson C; Tellier, Laurent Cam; Vattikuti, Shashaank; Purcell, Shaun M; Lee, James J

2015-01-01

PLINK 1 is a widely used open-source C/C++ toolset for genome-wide association studies (GWAS) and research in population genetics. However, the steady accumulation of data from imputation and whole-genome sequencing studies has exposed a strong need for faster and scalable implementations of key functions, such as logistic regression, linkage disequilibrium estimation, and genomic distance evaluation. In addition, GWAS and population-genetic data now frequently contain genotype likelihoods, phase information, and/or multiallelic variants, none of which can be represented by PLINK 1's primary data format. To address these issues, we are developing a second-generation codebase for PLINK. The first major release from this codebase, PLINK 1.9, introduces extensive use of bit-level parallelism, [Formula: see text]-time/constant-space Hardy-Weinberg equilibrium and Fisher's exact tests, and many other algorithmic improvements. In combination, these changes accelerate most operations by 1-4 orders of magnitude, and allow the program to handle datasets too large to fit in RAM. We have also developed an extension to the data format which adds low-overhead support for genotype likelihoods, phase, multiallelic variants, and reference vs. alternate alleles, which is the basis of our planned second release (PLINK 2.0). The second-generation versions of PLINK will offer dramatic improvements in performance and compatibility. For the first time, users without access to high-end computing resources can perform several essential analyses of the feature-rich and very large genetic datasets coming into use.

Optimization of the pepsin digestion method for anisakids inspection in the fishing industry.

PubMed

Llarena-Reino, María; Piñeiro, Carmen; Antonio, José; Outeriño, Luis; Vello, Carlos; González, Ángel F; Pascual, Santiago

2013-01-31

During the last 50 years human anisakiasis has been rising while parasites have increased their prevalence at determined fisheries becoming an emergent major public health problem. Although artificial enzymatic digestion procedure by CODEX (STAN 244-2004: standard for salted Atlantic herring and salted sprat) is the recommended protocol for anisakids inspection, no international agreement has been achieved in veterinary and scientific digestion protocols to regulate this growing source of biological hazard in fish products. The aim of this work was to optimize the current artificial digestion protocol by CODEX with the purpose of offering a faster, more useful and safer procedure for factories workers, than the current one for anisakids detection. To achieve these objectives, the existing pepsin chemicals and the conditions of the digestion method were evaluated and assayed in fresh and frozen samples, both in lean and fatty fish species. Results showed that the new digestion procedure considerably reduces the assay time, and it is more handy and efficient (the quantity of the resulting residue was considerably lower after less time) than the widely used CODEX procedure. In conclusion, the new digestion method herein proposed based on liquid pepsin format is an accurate reproducible and user-friendly off-site tool, that can be useful in the implementation of screening programs for the prevention of human anisakiasis (and associated gastroallergic disorders) due to the consumption of raw or undercooked contaminated seafood products. Copyright © 2012 Elsevier B.V. All rights reserved.

The bleaching of teeth: a review of the literature.

PubMed

Joiner, Andrew

2006-08-01

To review current knowledge of tooth whitening with respect to external bleaching methods. The scope is the external bleaching of vital teeth and focuses on mechanisms; in vivo and in vitro measurement methods, and factors influencing the efficacy of the whitening process. "Medline" and "ISI Web of Science" databases from 1966 and 1974, respectively were searched electronically with key words tooth, teeth, colo*r, white*, bleach* and peroxide. The importance of tooth whitening for patients and consumers has seen a dramatic increase in the number of products and procedures over recent years, with a concomitant rise in publications on this topic. Literature suggests that the mechanisms of tooth whitening by peroxide occur by the diffusion of peroxide through enamel to cause oxidation and hence lightening of coloured species, particularly within the dentinal regions. A number of approaches are available for measuring changes in tooth colour. These include visual measurements by trained clinicians and instrumental measurements using spectrophotometry, chromameters and digital image analysis. The key factors that affect tooth whitening efficacy by peroxide containing products are concentration and time. In general, higher concentrations are faster than lower concentrations. However, lower concentrations can approach the efficacy of higher concentrations with extended treatment times. Alternative bleach systems to peroxide have received only minor attention. The efficacy of light activated systems versus non-light activated controls in clinical studies is limited and conflicting. Other factors which can influence tooth bleaching outcome include type of stain, initial tooth colour and subject age.

Critical Beach Habitat for Hawaiian Green Sea Turtle Endangered Before Mid-Century

NASA Astrophysics Data System (ADS)

Burstein, J. T.; Fletcher, C. H., III; Dominique Tavares, K.

2017-12-01

Many Hawaiian beaches provide critical habitat for the Hawaiian Green Sea Turtle (Chelonia Mydas). However, sea level rise drives beaches and dunes to migrate landward where they may encounter roads and other types of developed lands. Where developed lands are threatened by coastal erosion, defined as a distance of 20 ft (6.1 m) by state rules, property owners are eligible to apply for an emergency permit. These have historically led to coastal armoring. Seawalls and revetments on chronically receding shorelines cause permanent beach loss by restricting sand supply to the beach in front of the sea wall, as well as to beaches adjacent to the restrictive structure (flanking). This study focuses on four primary beach habitats along the North Shore of Oahu, Hawai'i: Waimea, Haleiwa, Kawailoa, and Mokuleia. We utilize GIS techniques to apply spatial analysis of nesting and basking locations collected from the National Oceanic Atmospheric Administration (NOAA). We then estimate the number of homes and the length of shoreline threatened by coastal armoring for 0 m, 0.17 m, 0.32 m, 0.60 m, and 0.98 m of sea-level rise. We demonstrate that 0.17 m of sea level rise impacts 31% of all beach front homes, and 4.6 km of shoreline, or 21% of the total shoreline. An increase to 0.32 m of sea level rise impacts 42% of all beach front homes, and 5.8 km of shoreline, or 31% of the total shoreline. The upper bound of the most recent sea level rise projection by the International Panel on Climate Change (IPCC RCP 8.5) affirms that 0.17 m of sea level rise may be reached by 2030, and 0.32 m by 2050. This sea level projection is a "worst-case" under IPCC-AR5, however, Sweet et al. (2017) depicts this as an "Intermediate" scenario on the basis of faster than expected mass loss by Greenland and Antarctica ice sheets, and rapid heat uptake and thermal expansion by the world's oceans. We conclude that the impacts of sea level rise and reactive coastal armoring currently endanger critical habitat for the Hawaiian Green Sea turtle (Chelonia Mydas). The results of this study suggest that decision-makers need to act without delay in developing habitat management plans to protect and preserve Hawai'i's shorelines, and conserve critical habitats for the Hawaiian Green Sea turtle and other indigenous species.

An Analytic Tool to Investigate the Effect of Binder on the Sensitivity of HMX-Based Plastic Bonded Explosives in the Skid Test

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

Hayden, D. W.

This project will develop an analytical tool to calculate performance of HMX based PBXs in the skid test. The skid-test is used as a means to measure sensitivity for large charges in handling situations. Each series of skid tests requires dozens of drops of large billets. It is proposed that the reaction (or lack of one) of PBXs in the skid test is governed by the mechanical properties of the binder. If true, one might be able to develop an analytical tool to estimate skid test behavior for new PBX formulations. Others over the past 50 years have tried tomore » develop similar models. This project will research and summarize the works of others and couple the work of 3 into an analytical tool that can be run on a PC to calculate drop height of HMX based PBXs. Detonation due to dropping a billet is argued to be a dynamic thermal event. To avoid detonation, the heat created due to friction at impact, must be conducted into the charge or the target faster than the chemical kinetics can create additional energy. The methodology will involve numerically solving the Frank-Kamenetskii equation in one dimension. The analytical problem needs to be bounded in terms of how much heat is introduced to the billet and for how long. Assuming an inelastic collision with no rebound, the billet will be in contact with the target for a short duration determined by the equations of motion. For the purposes of the calculations, it will be assumed that if a detonation is to occur, it will transpire within that time. The surface temperature will be raised according to the friction created using the equations of motion of dropping the billet on a rigid surface. The study will connect the works of Charles Anderson, Alan Randolph, Larry Hatler, Alfonse Popolato, and Charles Mader into a single PC based analytic tool. Anderson's equations of motion will be used to calculate the temperature rise upon impact, the time this temperature is maintained (contact time) will be obtained from the work of Hatler et. al., and the reactive temperature rise will be obtained from Mader's work. Finally, the assessment of when a detonation occurs will be derived from Bowden and Yoffe's thermal explosion theory (hot spot).« less

New context and old challenges in the healthcare system.

PubMed

Peiró, Manel; Barrubés, Joan

2012-07-01

The economic crisis cannot conceal the need for transformation of the National Health System. The financial difficulties of healthcare systems whose spending is growing at a faster rate than the economy have been well known for years. The development and diffusion of new technologies, increased use of health services, rising drug costs, inflation of prices, and the inefficiency of the system explain the new context. The challenges facing the healthcare system are not new: address the debt, improve funding, review the list of services, transform the governance of the system and provide the institutions with real management autonomy. The gravity of the economic situation can be an opportunity to carry out the long-awaited changes. Copyright © 2012 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

On the Physics of Fizziness: How Bubble Bursting Controls Droplets Ejection

NASA Astrophysics Data System (ADS)

Seon, Thomas; Ghabache, Elisabeth; Antkowiak, Arnaud; Josserand, Christophe

2014-11-01

Either in a champagne glass or at the oceanic scales, the tiny bubbles rising at the surface burst in ejecting myriads of droplets. Focusing on the bubble bursting jet, prelude for these aerosols, we propose a simple scaling for the jet velocity, we unravel experimentally the intricate roles of bubble shape, capillary waves and liquid properties, and we demonstrate that droplets ejection can be tuned by changing the liquid properties. In particular, as capillary waves are shown to always evolve into a self-similar collapsing cavity, faster and smaller droplets can be produced by sheltering this collapse from remnant ripples using damping action of viscosity. These results pave the road to the characterization and control of the bursting bubble aerosols. Applications to champagne aroma diffusion will be discussed.

Costs of a medical education: comparison with graduate education in law and business.

PubMed

Kerr, Jason R; Brown, Jeffrey J

2006-02-01

The costs of graduate school education are climbing, particularly within the fields of medicine, law, and business. Data on graduate level tuition, educational debt, and starting salaries for medical school, law school, and business school graduates were collected directly from universities and from a wide range of published reports and surveys. Medical school tuition and educational debt levels have risen faster than the rate of inflation over the past decade. Medical school graduates have longer training periods and lower starting salaries than law school and business school graduates, although physician salaries rise after completion of post-graduate education. Faced with an early debt burden and delayed entry into the work force, careful planning is required for medical school graduates to pay off their loans and save for retirement.

Parasail: SIMD C library for global, semi-global, and local pairwise sequence alignments.

PubMed

Daily, Jeff

2016-02-10

Sequence alignment algorithms are a key component of many bioinformatics applications. Though various fast Smith-Waterman local sequence alignment implementations have been developed for x86 CPUs, most are embedded into larger database search tools. In addition, fast implementations of Needleman-Wunsch global sequence alignment and its semi-global variants are not as widespread. This article presents the first software library for local, global, and semi-global pairwise intra-sequence alignments and improves the performance of previous intra-sequence implementations. A faster intra-sequence local pairwise alignment implementation is described and benchmarked, including new global and semi-global variants. Using a 375 residue query sequence a speed of 136 billion cell updates per second (GCUPS) was achieved on a dual Intel Xeon E5-2670 24-core processor system, the highest reported for an implementation based on Farrar's 'striped' approach. Rognes's SWIPE optimal database search application is still generally the fastest available at 1.2 to at best 2.4 times faster than Parasail for sequences shorter than 500 amino acids. However, Parasail was faster for longer sequences. For global alignments, Parasail's prefix scan implementation is generally the fastest, faster even than Farrar's 'striped' approach, however the opal library is faster for single-threaded applications. The software library is designed for 64 bit Linux, OS X, or Windows on processors with SSE2, SSE41, or AVX2. Source code is available from https://github.com/jeffdaily/parasail under the Battelle BSD-style license. Applications that require optimal alignment scores could benefit from the improved performance. For the first time, SIMD global, semi-global, and local alignments are available in a stand-alone C library.

Sex differences in the oxygen delivery, extraction, and uptake during moderate-walking exercise transition.

PubMed

Beltrame, Thomas; Villar, Rodrigo; Hughson, Richard L

2017-09-01

Previous studies in children and older adults demonstrated faster oxygen uptake (V̇O 2 ) kinetics in males compared with females, but young healthy adults have not been studied. We hypothesized that young men would have faster aerobic system dynamics in response to the onset of exercise than women. Interactions between oxygen supply and utilization were characterized by the dynamics of V̇O 2 , deoxyhemoglobin (HHb), tissue saturation index (TSI), cardiac output (Q̇), and calculated arteriovenous O 2 difference (a-vO 2 diff ) in women and men. Eighteen healthy active young women and men (9 of each sex) with similar aerobic fitness levels volunteered for this study. Participants performed an incremental cardiopulmonary treadmill exercise test and 3 moderate-intensity treadmill exercise tests (at 80% V̇O 2 of gas exchange threshold). Data related to the moderate exercise were submitted to exponential data modelling to obtain parameters related to the aerobic system dynamics. The time constants of V̇O 2 , a-vO 2 diff , HHb, and TSI (30 ± 6, 29 ± 1, 16 ± 1, and 15 ± 2 s, respectively) in women were statistically (p < 0.05) faster than the time constants in men (42 ± 10, 49 ± 21, 19 ± 3, and 20 ± 4 s, respectively). Although Q̇ dynamics were not statistically different (p = 0.06) between groups, there was a trend to slower Q̇ dynamics in men corresponding with the slower V̇O 2 kinetics. These results indicated that the peripheral and pulmonary oxygen extraction dynamics were remarkably faster in women. Thus, contrary to the hypothesis, V̇O 2 dynamics measured at the mouth at the onset of submaximal treadmill walking were faster in women compared with men.

Driving at Night Can Be Deadly

DOT National Transportation Integrated Search

1996-06-17

Efficient Commercial Vehicle Operations (CVO) is imperative as manufacturers and distributors move to new technologies, faster production methods and "Just in Time" delivery. CVO must offer more reliable travel times, as well as safety and flexibilit...

The Resistance to Deformation and Facture of Magnesium MA2-1 Under Shock-Wave Loading at 293 K and 823 K of the Temperature

NASA Astrophysics Data System (ADS)

Garkushin, Gennady; Kanel, Gennady; Razorenov, Sergey

2011-06-01

The spall strength and elastic-plastic response have been measured with the VISAR for MA2-1 (94.2% Mg, 0.4 % Mn, 4.4% Al, 1% Zn) alloy at temperatures from 293 K to 823 K. The decay of elastic precursor wave at 293 K is approximately in reverse proportionality with the cubic root from the distance that corresponds to decrease of plastic strain rate from 5 ×105 s-1 at 0.25 mm (213 MPa of the shear stress) down to 5 ×103 s-1 at 10 mm (63 MPa shear stress). An analysis of the rise times of plastic shock waves shows by order of magnitude faster plastic strain rates at corresponding shear stresses than that at the HEL. The decay of elastic precursor wave is weaker and the dependence of initial plastic strain rate on the shear stress at HEL is stronger than that was observed for aluminum. Unlike to aluminum, the magnesium alloy does not exhibit anomalous thermal hardening: the HEL values at 823 K are close to the values at room temperatures. The temperature increase from 293 K to 823 K has led to significant decrease of the spall strength.

Expanded Very Large Array Nova Project Observations of the Classical Nova V1723 Aquilae

NASA Astrophysics Data System (ADS)

Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.; O'Brien, T. J.

2011-09-01

We present radio light curves and spectra of the classical nova V1723 Aql obtained with the Expanded Very Large Array (EVLA). This is the first paper to showcase results from the EVLA Nova Project, which comprises a team of observers and theorists utilizing the greatly enhanced sensitivity and frequency coverage of EVLA radio observations, along with observations at other wavelengths, to reach a deeper understanding of the energetics, morphology, and temporal characteristics of nova explosions. Our observations of V1723 Aql span 1-37 GHz in frequency, and we report on data from 14 to 175 days following the time of the nova explosion. The broad frequency coverage and frequent monitoring show that the radio behavior of V1723 Aql does not follow the classic Hubble-flow model of homologous spherically expanding thermal ejecta. The spectra are always at least partially optically thin, and the flux rises on faster timescales than can be reproduced with linear expansion. Therefore, any description of the underlying physical processes must go beyond this simple picture. The unusual spectral properties and light curve evolution might be explained by multiple emitting regions or shocked material. Indeed, X-ray observations from Swift reveal that shocks are likely present.

Stress exposure in early post-natal life reduces telomere length: an experimental demonstration in a long-lived seabird

PubMed Central

Herborn, Katherine A.; Heidinger, Britt J.; Boner, Winnie; Noguera, Jose C.; Adam, Aileen; Daunt, Francis; Monaghan, Pat

2014-01-01

Exposure to stressors early in life is associated with faster ageing and reduced longevity. One important mechanism that could underlie these late life effects is increased telomere loss. Telomere length in early post-natal life is an important predictor of subsequent lifespan, but the factors underpinning its variability are poorly understood. Recent human studies have linked stress exposure to increased telomere loss. These studies have of necessity been non-experimental and are consequently subjected to several confounding factors; also, being based on leucocyte populations, where cell composition is variable and some telomere restoration can occur, the extent to which these effects extend beyond the immune system has been questioned. In this study, we experimentally manipulated stress exposure early in post-natal life in nestling European shags (Phalacrocorax aristotelis) in the wild and examined the effect on telomere length in erythrocytes. Our results show that greater stress exposure during early post-natal life increases telomere loss at this life-history stage, and that such an effect is not confined to immune cells. The delayed effects of increased telomere attrition in early life could therefore give rise to a ‘time bomb’ that reduces longevity in the absence of any obvious phenotypic consequences early in life. PMID:24648221

Numerical Investigation on Head and Brain Injuries Caused by Windshield Impact on Riders Using Electric Self-Balancing Scooters

PubMed Central

Zheng, Yanting; Shen, Ming; Yang, Xianfeng

2018-01-01

To investigate head-brain injuries caused by windshield impact on riders using electric self-balancing scooters (ESS). Numerical vehicle ESS crash scenarios are constructed by combining the finite element (FE) vehicle model and multibody scooter/rider models. Impact kinematic postures of the head-windshield contact under various impact conditions are captured. Then, the processes during head-windshield contact are reconstructed using validated FE head/laminated windshield models to assess the severity of brain injury caused by the head-windshield contact. Governing factors, such as vehicle speed, ESS speed, and the initial orientation of ESS rider, have nontrivial influences over the severity of a rider's brain injuries. Results also show positive correlations between vehicle speed and head-windshield impact speeds (linear and angular). Meanwhile, the time of head-windshield contact happens earlier when the vehicle speed is faster. According to the intensive study, windshield-head contact speed (linear and angular), impact location on the windshield, and head collision area are found to be direct factors on ESS riders' brain injuries during an impact. The von Mises stress and shear stress rise when relative contact speed of head-windshield increases. Brain injury indices vary widely when the head impacting the windshield from center to the edge or impacting with different areas. PMID:29770161

Effects of Cascaded Voltage Collapse and Protection of Many Induction Machine Loads upon Load Characteristics Viewed from Bulk Transmission System

NASA Astrophysics Data System (ADS)

Kumano, Teruhisa

As known well, two of the fundamental processes which give rise to voltage collapse in power systems are the on load tap changers of transformers and dynamic characteristics of loads such as induction machines. It has been well established that, comparing among these two, the former makes slower collapse while the latter makes faster. However, in realistic situations, the load level of each induction machine is not uniform and it is well expected that only a part of loads collapses first, followed by collapse process of each load which did not go into instability during the preceding collapses. In such situations the over all equivalent collapse behavior viewed from bulk transmission level becomes somewhat different from the simple collapse driven by one aggregated induction machine. This paper studies the process of cascaded voltage collapse among many induction machines by time simulation, where load distribution on a feeder line is modeled by several hundreds of induction machines and static impedance loads. It is shown that in some cases voltage collapse really cascades among induction machines, where the macroscopic load dynamics viewed from upper voltage level makes slower collapse than expected by the aggregated load model. Also shown is the effects of machine protection of induction machines, which also makes slower collapse.

Foreign trade and early industrialisation in the Habsburg Monarchy and the United Kingdom - Two extremes in comparison.

PubMed

Gingrich, Simone

2011-05-15

The concept of socio-ecological transitions is used to analyse the quantitative importance of physical imports and exports for the Habsburg Empire and the United Kingdom in the 19th and early 20th centuries. For the Habsburg Empire, a new dataset of foreign trade and social metabolism is presented. For the United Kingdom, the analysis relies on previously published data. Foreign trade volumes increased in both countries in the long run. Total trade volumes were much higher in the United Kingdom throughout the entire time period, on average by around a factor four. Physical factors explaining the disparities in structure and volume of foreign trade in the two countries are differences in (1) the temporal patterns of the socio-ecological transition and (2) domestic resource endowments. In both countries, energy carrying materials, i.e. fossil fuels and biomass, were the dominant resources in physical foreign trade. The analysis focuses on the physically most important material groups: coal, wood and cereals, and discusses the role of imports and exports in relation to domestic resource provision and environmental pressures. Physical foreign trade increased at a faster pace than domestic resource extraction and consumption. The socio-ecological transition was thus accompanied by rising international integration of resource supply.

Foreign trade and early industrialisation in the Habsburg Monarchy and the United Kingdom — Two extremes in comparison

PubMed Central

Gingrich, Simone

2011-01-01

The concept of socio–ecological transitions is used to analyse the quantitative importance of physical imports and exports for the Habsburg Empire and the United Kingdom in the 19th and early 20th centuries. For the Habsburg Empire, a new dataset of foreign trade and social metabolism is presented. For the United Kingdom, the analysis relies on previously published data. Foreign trade volumes increased in both countries in the long run. Total trade volumes were much higher in the United Kingdom throughout the entire time period, on average by around a factor four. Physical factors explaining the disparities in structure and volume of foreign trade in the two countries are differences in (1) the temporal patterns of the socio-ecological transition and (2) domestic resource endowments. In both countries, energy carrying materials, i.e. fossil fuels and biomass, were the dominant resources in physical foreign trade. The analysis focuses on the physically most important material groups: coal, wood and cereals, and discusses the role of imports and exports in relation to domestic resource provision and environmental pressures. Physical foreign trade increased at a faster pace than domestic resource extraction and consumption. The socio–ecological transition was thus accompanied by rising international integration of resource supply. PMID:21760665

Effect of CNT as a Nucleating Agent on Cell Morphology and Thermal Insulation Property of the Rigid Polyurethane Foams.

PubMed

Ahn, WonSool; Lee, Joon-Man

2015-11-01

The effects of MWCNT on the cell sizes, cell uniformities, thermal conductivities, bulk densities, foaming kinetics, and compressive mechanical properties of the rigid PUFs were investigated. To obtain the better uniform dispersed state of MWCNT, grease-type master batch of MWCNT/surfactant was prepared by three-roll mill. Average cell size of the PUF samples decreased from 185.1 for the neat PUF to 162.9 μm for the sample of 0.01 phr of MWCNT concentration. Cell uniformity was also enhanced showing the standard cell-size deviation of 61.7 and 35.2, respectively. While the thermal conductivity of the neat PUF was 0.0222 W/m(o)K, that of the sample with 0.01 phr of MWCNT showed 0.0204 W/m(o)K, resulting 8.2% reduction of the thermal conductivity. Bulk density of the PUF samples was observed as nearly the same values as 30.0 ± 1.0 g/cm3 regardless of MWCNT. Temperature profiles during foaming process showed that an indirect indication of the nucleation effect of MWCNT for the PUF foaming system, showing faster and higher temperature rising with time. The compressive yield stress is nearly the same as 0.030 x 10(5) Pa regardless of MWCNT.

Remote access laboratories in Australia and Europe

NASA Astrophysics Data System (ADS)

Ku, H.; Ahfock, T.; Yusaf, T.

2011-06-01

Remote access laboratories (RALs) were first developed in 1994 in Australia and Switzerland. The main purposes of developing them are to enable students to do their experiments at their own pace, time and locations and to enable students and teaching staff to get access to facilities beyond their institutions. Currently, most of the experiments carried out through RALs in Australia are heavily biased towards electrical, electronic and computer engineering disciplines. However, the experiments carried out through RALs in Europe had more variety, in addition to the traditional electrical, electronic and computer engineering disciplines, there were experiments in mechanical and mechatronic disciplines. It was found that RALs are now being developed aggressively in Australia and Europe and it can be argued that RALs will develop further and faster in the future with improving Internet technology. The rising costs of real experimental equipment will also speed up their development because by making the equipment remotely accessible, the cost can be shared by more universities or institutions and this will improve their cost-effectiveness. Their development would be particularly rapid in large countries with small populations such as Australia, Canada and Russia, because of the scale of economy. Reusability of software, interoperability in software implementation, computer supported collaborative learning and convergence with learning management systems are the required development of future RALs.

Noise Enhances Action Potential Generation in Mouse Sensory Neurons via Stochastic Resonance.

PubMed

Onorato, Irene; D'Alessandro, Giuseppina; Di Castro, Maria Amalia; Renzi, Massimiliano; Dobrowolny, Gabriella; Musarò, Antonio; Salvetti, Marco; Limatola, Cristina; Crisanti, Andrea; Grassi, Francesca

2016-01-01

Noise can enhance perception of tactile and proprioceptive stimuli by stochastic resonance processes. However, the mechanisms underlying this general phenomenon remain to be characterized. Here we studied how externally applied noise influences action potential firing in mouse primary sensory neurons of dorsal root ganglia, modelling a basic process in sensory perception. Since noisy mechanical stimuli may cause stochastic fluctuations in receptor potential, we examined the effects of sub-threshold depolarizing current steps with superimposed random fluctuations. We performed whole cell patch clamp recordings in cultured neurons of mouse dorsal root ganglia. Noise was added either before and during the step, or during the depolarizing step only, to focus onto the specific effects of external noise on action potential generation. In both cases, step + noise stimuli triggered significantly more action potentials than steps alone. The normalized power norm had a clear peak at intermediate noise levels, demonstrating that the phenomenon is driven by stochastic resonance. Spikes evoked in step + noise trials occur earlier and show faster rise time as compared to the occasional ones elicited by steps alone. These data suggest that external noise enhances, via stochastic resonance, the recruitment of transient voltage-gated Na channels, responsible for action potential firing in response to rapid step-wise depolarizing currents.

Hydrogen-bond memory and water-skin supersolidity resolving the Mpemba paradox.

PubMed

Zhang, Xi; Huang, Yongli; Ma, Zengsheng; Zhou, Yichun; Zhou, Ji; Zheng, Weitao; Jiang, Qing; Sun, Chang Q

2014-11-14

The Mpemba paradox, that is, hotter water freezes faster than colder water, has baffled thinkers like Francis Bacon, René Descartes, and Aristotle since B.C. 350. However, a commonly accepted understanding or theoretical reproduction of this effect remains challenging. Numerical reproduction of observations, shown herewith, confirms that water skin supersolidity [Zhang et al., Phys. Chem. Chem. Phys., DOI: ] enhances the local thermal diffusivity favoring heat flowing outwardly in the liquid path. Analysis of experimental database reveals that the hydrogen bond (O:H-O) possesses memory to emit energy at a rate depending on its initial storage. Unlike other usual materials that lengthen and soften all bonds when they absorb thermal energy, water performs abnormally under heating to lengthen the O:H nonbond and shorten the H-O covalent bond through inter-oxygen Coulomb coupling [Sun et al., J. Phys. Chem. Lett., 2013, 4, 3238]. Cooling does the opposite to release energy, like releasing a coupled pair of bungees, at a rate of history dependence. Being sensitive to the source volume, skin radiation, and the drain temperature, the Mpemba effect proceeds only in the strictly non-adiabatic 'source-path-drain' cycling system for the heat "emission-conduction-dissipation" dynamics with a relaxation time that drops exponentially with the rise of the initial temperature of the liquid source.

Noise Enhances Action Potential Generation in Mouse Sensory Neurons via Stochastic Resonance

PubMed Central

Onorato, Irene; D'Alessandro, Giuseppina; Di Castro, Maria Amalia; Renzi, Massimiliano; Dobrowolny, Gabriella; Musarò, Antonio; Salvetti, Marco; Limatola, Cristina; Crisanti, Andrea; Grassi, Francesca

2016-01-01

Noise can enhance perception of tactile and proprioceptive stimuli by stochastic resonance processes. However, the mechanisms underlying this general phenomenon remain to be characterized. Here we studied how externally applied noise influences action potential firing in mouse primary sensory neurons of dorsal root ganglia, modelling a basic process in sensory perception. Since noisy mechanical stimuli may cause stochastic fluctuations in receptor potential, we examined the effects of sub-threshold depolarizing current steps with superimposed random fluctuations. We performed whole cell patch clamp recordings in cultured neurons of mouse dorsal root ganglia. Noise was added either before and during the step, or during the depolarizing step only, to focus onto the specific effects of external noise on action potential generation. In both cases, step + noise stimuli triggered significantly more action potentials than steps alone. The normalized power norm had a clear peak at intermediate noise levels, demonstrating that the phenomenon is driven by stochastic resonance. Spikes evoked in step + noise trials occur earlier and show faster rise time as compared to the occasional ones elicited by steps alone. These data suggest that external noise enhances, via stochastic resonance, the recruitment of transient voltage-gated Na channels, responsible for action potential firing in response to rapid step-wise depolarizing currents. PMID:27525414

Expanded Very Large Array Nova Project Observations of the Classical NovaV1723 Aquilae

NASA Technical Reports Server (NTRS)

Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.;