The current state of resident training in genomic pathology: a comprehensive analysis utilizing the Resident In-Service Exam (RISE)

PubMed Central

Haspel, Richard L.; Rinder, Henry M.; Frank, Karen M.; Wagner, Jay; Ali, Asma M.; Fisher, Patrick B.; Parks, Eric R.

2014-01-01

Objectives To determine the current state of pathology resident training in genomic and molecular pathology. Methods The Training Residents in Genomics (TRIG) Working Group developed survey and knowledge questions for the 2013 Pathology Resident In-Service Examination (RISE). Sixteen demographic questions related to amount of training, current and predicted future use, and perceived ability in molecular pathology vs. genomic medicine were included along with five genomic pathology and 19 molecular pathology knowledge questions. Results A total of 2,506 pathology residents took the 2013 RISE with approximately 600 individuals per post-graduate year (PGY). For genomic medicine, 42% of PGY-4 respondents stated they had no training compared to 7% for molecular pathology (p<0.001). PGY-4 resident perceived ability in genomic medicine, comfort in discussing results, and predicted future use as a practicing pathologist were less than reported for molecular pathology (p<0.001). There was a greater increase by PGY in knowledge question scores for molecular than for genomic pathology. Conclusions The RISE is a powerful tool in assessing the state of resident training in genomic pathology and current results suggest a significant deficit. The results also provide a baseline to assess future initiatives to improve genomics education for pathology residents such as those developed by the TRIG Working Group. PMID:25239410

Onset of thermomagnetic convection around a vertically oriented hot-wire in ferrofluid

NASA Astrophysics Data System (ADS)

Vatani, Ashkan; Woodfield, Peter Lloyd; Nguyen, Nam-Trung; Dao, Dzung Viet

2018-06-01

The onset of thermomagnetic convection in ferrofluid in a vertical transient hot-wire cell is analytically and experimentally investigated by studying the temperature rise of an electrically-heated wire. During the initial stage of heating, the temperature rise is found to correspond well to that predicted by conduction only. For high electrical current densities, the initial heating stage is followed by a sudden change in the slope of the temperature rise with respect to time as a result of the onset of thermomagnetic convection cooling. The observed onset of thermomagnetic convection was then compared to that of natural convection of deionized water. For the first time, the critical time corresponding to the onset of thermomagnetic convection around an electrically-heated wire is characterized and non-dimensionalized as a critical Fourier number (Foc). We propose an equation for Foc as a function of a magnetic Rayleigh number to predict the time for the onset of thermomagnetic convection. We observed that thermomagnetic convection in ferrofluid occurs earlier than natural convection in non-magnetic fluids for similar experimental conditions. The onset of thermomagnetic convection is dependent on the current supplied to the wire. The findings have important implications for cooling of high-power electronics using ferrofluids and for measuring thermal properties of ferrofluids.

Modeling pressure rise in gas targets

NASA Astrophysics Data System (ADS)

Jahangiri, P.; Lapi, S. E.; Publicover, J.; Buckley, K.; Martinez, D. M.; Ruth, T. J.; Hoehr, C.

2017-05-01

The purpose of this work is to introduce a universal mathematical model to explain a gas target behaviour at steady-state time scale. To obtain our final goal, an analytical model is proposed to study the pressure rise in the targets used to produce medical isotopes on low-energy cyclotrons. The model is developed based on the assumption that during irradiation the system reaches steady-state. The model is verified by various experiments performed at different beam currents, gas type, and initial pressures at 13 MeV cyclotron at TRIUMF. Excellent agreement is achieved.

Epitaxial thinning process

NASA Technical Reports Server (NTRS)

Siegel, C. M. (Inventor)

1984-01-01

A method is described for thinning an epitaxial layer of a wafer that is to be used in producing diodes having a specified breakdown voltage and which also facilitates the thinning process. Current is passed through the epitaxial layer, by connecting a current source between the substrate of the wafer and an electrolyte in which the wafer is immersed. When the wafer is initially immersed, the voltage across the wafer initially drops and then rises at a steep rate. When light is applied to the wafer the voltage drops, and when the light is interrupted the voltage rises again. These changes in voltage, each indicate the breakdown voltage of a Schottky diode that could be prepared from the wafer at that time. The epitaxial layer is thinned by continuing to apply current through the wafer while it is immersed and light is applied, to form an oxide film and when the oxide film is thick the wafer can then be cleaned of oxide and the testing and thinning continued. Uninterrupted thinning can be achieved by first forming an oxide film, and then using an electrolyte that dissolves the oxide about as fast as it is being formed, to limit the thickness of the oxide layer.

Current & future vulnerability of sarasota county Florida to hurricane storm surge & sea level rise

USGS Publications Warehouse

Frazier, T.; Wood, N.; Yarnal, B.

2008-01-01

Coastal communities in portions of the United States are vulnerable to storm-surge inundation from hurricanes and this vulnerability will likely increase, given predicted rises in sea level from climate change and growing coastal development. In this paper, we provide an overview of research to determine current and future societal vulnerability to hurricane storm-surge inundation and to help public officials and planners integrate these scenarios into their long-range land use plans. Our case study is Sarasota County, Florida, where planners face the challenge of balancing increasing population growth and development with the desire to lower vulnerability to storm surge. Initial results indicate that a large proportion of Sarasota County's residential and employee populations are in areas prone to storm-surge inundation from a Category 5 hurricane. This hazard zone increases when accounting for potential sea-level-rise scenarios, thereby putting additional populations at risk. Subsequent project phases involve the development of future land use and vulnerability scenarios in collaboration with local officials. Copyright ASCE 2008.

INITIATION AND ERUPTION PROCESS OF MAGNETIC FLUX ROPE FROM SOLAR ACTIVE REGION NOAA 11719 TO EARTH-DIRECTED CME

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

Vemareddy, P.; Zhang, J., E-mail: vema@prl.res.in

An eruption event launched from the solar active region (AR) NOAA 11719 is investigated based on coronal EUV observations and photospheric magnetic field measurements obtained from the Solar Dynamic Observatory. The AR consists of a filament channel originating from a major sunspot and its south section is associated with an inverse-S sigmoidal system as observed in Atmospheric Imaging Assembly passbands. We regard the sigmoid as the main body of the flux rope (FR). There also exists a twisted flux bundle crossing over this FR. This overlying flux bundle transforms in shape similar to kink-rise evolution, which corresponds with the risemore » motion of the FR. The emission measure and temperature along the FR exhibits an increasing trend with its rising motion, indicating reconnection in the thinning current sheet underneath the FR. Net magnetic flux of the AR, evaluated at north and south polarities, showed decreasing behavior whereas the net current in these fluxes exhibits an increasing trend. Because the negative (positive) flux has a dominant positive (negative) current, the chirality of AR flux system is likely negative (left handed) in order to be consistent with the chirality of inverse S-sigmoidal FR. This analysis of magnetic fields of the source AR suggests that the cancelling fluxes are prime factors of the monotonous twisting of the FR system, reaching to a critical state to trigger kink instability and rise motion. This rise motion may have led to the onset of the torus instability, resulting in an Earth-directed coronal mass ejection, and the progressive reconnection in the thinning current sheet beneath the rising FR led to the M6.5 flare.« less

The Global Neighborhood: Programming Initiatives with International Living-Learning Communities

ERIC Educational Resources Information Center

McClanahan, Sarah

2014-01-01

The United States is currently enrolling more international students than any other country in the world. In 2011, approximately 764,000 international students were enrolled in higher education in the U.S., comprising 19% of the world's total students studying internationally (Institute of International Education, 2012). This rise, as well as the…

Large-eddy simulation study of oil/gas plumes in stratified fluid with cross current

NASA Astrophysics Data System (ADS)

Yang, Di; Xiao, Shuolin; Chen, Bicheng; Chamecki, Marcelo; Meneveau, Charles

2017-11-01

Dynamics of the oil/gas plume from a subsea blowout are strongly affected by the seawater stratification and cross current. The buoyant plume entrains ambient seawater and lifts it up to higher elevations. During the rising process, the continuously increasing density difference between the entrained and ambient seawater caused by the stable stratification eventually results in a detrainment of the entrained seawater and small oil droplets at a height of maximum rise (peel height), forming a downward plume outside the rising inner plume. The presence of a cross current breaks the plume's axisymmetry and causes the outer plume to fall along the downstream side of the inner plume. The detrained seawater and oil eventually fall to a neutral buoyancy level (trap height), and disperse horizontally to form an intrusion layer. In this study, the complex plume dynamics is investigated using large-eddy simulation (LES). Various laboratory and field scale cases are simulated to explore the effect of cross current and stratification on the plume dynamics. Based on the LES data, various turbulence statistics of the plume are systematically quantified, leading to some useful insights for modeling the mean plume dynamics using integral plume models. This research is made possible by a RFP-V Grant from The Gulf of Mexico Research Initiative.

Current pulse: can a production system reduce medical errors in health care?

PubMed

Printezis, Antonios; Gopalakrishnan, Mohan

2007-01-01

One of the reasons for rising health care costs is medical errors, a majority of which result from faulty systems and processes. Health care in the past has used process-based initiatives such as Total Quality Management, Continuous Quality Improvement, and Six Sigma to reduce errors. These initiatives to redesign health care, reduce errors, and improve overall efficiency and customer satisfaction have had moderate success. Current trend is to apply the successful Toyota Production System (TPS) to health care since its organizing principles have led to tremendous improvement in productivity and quality for Toyota and other businesses that have adapted them. This article presents insights on the effectiveness of TPS principles in health care and the challenges that lie ahead in successfully integrating this approach with other quality initiatives.

Cluster kinetics model of particle separation in vibrated granular media.

PubMed

McCoy, Benjamin J; Madras, Giridhar

2006-01-01

We model the Brazil-nut effect (BNE) by hypothesizing that granules form clusters that fragment and aggregate. This provides a heterogeneous medium in which the immersed intruder particle rises (BNE) or sinks (reverse BNE) according to relative convection currents and buoyant and drag forces. A simple relationship proposed for viscous drag in terms of the vibrational intensity and the particle to grain density ratio allows simulation of published experimental data for rise and sink times as functions of particle radius, initial depth of the particle, and particle-grain density ratio. The proposed model correctly describes the experimentally observed maximum in risetime.

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.

Biophysical mechanism of spike threshold dependence on the rate of rise of the membrane potential by sodium channel inactivation or subthreshold axonal potassium current

PubMed Central

Wester, Jason C.

2013-01-01

Spike threshold filters incoming inputs and thus gates activity flow through neuronal networks. Threshold is variable, and in many types of neurons there is a relationship between the threshold voltage and the rate of rise of the membrane potential (dVm/dt) leading to the spike. In primary sensory cortex this relationship enhances the sensitivity of neurons to a particular stimulus feature. While Na+ channel inactivation may contribute to this relationship, recent evidence indicates that K+ currents located in the spike initiation zone are crucial. Here we used a simple Hodgkin-Huxley biophysical model to systematically investigate the role of K+ and Na+ current parameters (activation voltages and kinetics) in regulating spike threshold as a function of dVm/dt. Threshold was determined empirically and not estimated from the shape of the Vm prior to a spike. This allowed us to investigate intrinsic currents and values of gating variables at the precise voltage threshold. We found that Na+ inactivation is sufficient to produce the relationship provided it occurs at hyperpolarized voltages combined with slow kinetics. Alternatively, hyperpolarization of the K+ current activation voltage, even in the absence of Na+ inactivation, is also sufficient to produce the relationship. This hyperpolarized shift of K+ activation allows an outward current prior to spike initiation to antagonize the Na+ inward current such that it becomes self-sustaining at a more depolarized voltage. Our simulations demonstrate parameter constraints on Na+ inactivation and the biophysical mechanism by which an outward current regulates spike threshold as a function of dVm/dt. PMID:23344915

Afro-Caribbean Women Teachers Recruited for U.S. Urban Schools: A Narrative Analysis of Experience, Change, and Perception

ERIC Educational Resources Information Center

Beck, Makini

2010-01-01

Current initiatives to recruit international teachers are on the rise. Although international teachers have always played a part in educating American students, their presence in U.S. schools have increased over the past few years as a result of overseas recruitment programs (Francis, 2005; Hutchinson, 2007). This increase in the recruitment of…

An experimental study on the thermal characteristics and heating effect of arc-fault from Cu core in residential electrical wiring fires

PubMed Central

Du, Jian-Hua; Zeng, Yi; Pan, Leng; Zhang, Ren-Cheng

2017-01-01

The characteristics of a series direct current (DC) arc-fault including both electrical and thermal parameters were investigated based on an arc-fault simulator to provide references for multi-parameter electrical fire detection method. Tests on arc fault behavior with three different initial circuit voltages, resistances and arc gaps were conducted, respectively. The influences of circuit conditions on arc dynamic image, voltage, current or power were interpreted. Also, the temperature rises of electrode surface and ambient air were studied. The results showed that, first, significant variations of arc structure and light emitting were observed under different conditions. A thin outer burning layer of vapor generated from electrodes with orange light was found due to the extremely high arc temperature. Second, with the increasing electrode gap in discharging, the arc power was shown to have a non monotonic relationship with arc length for constant initial circuit voltage and resistance. Finally, the temperature rises of electrode surface caused by heat transfer from arc were found to be not sensitive with increasing arc length due to special heat transfer mechanism. In addition, temperature of ambient air showed a large gradient in radial direction of arc. PMID:28797055

An experimental study on the thermal characteristics and heating effect of arc-fault from Cu core in residential electrical wiring fires.

PubMed

Du, Jian-Hua; Tu, Ran; Zeng, Yi; Pan, Leng; Zhang, Ren-Cheng

2017-01-01

The characteristics of a series direct current (DC) arc-fault including both electrical and thermal parameters were investigated based on an arc-fault simulator to provide references for multi-parameter electrical fire detection method. Tests on arc fault behavior with three different initial circuit voltages, resistances and arc gaps were conducted, respectively. The influences of circuit conditions on arc dynamic image, voltage, current or power were interpreted. Also, the temperature rises of electrode surface and ambient air were studied. The results showed that, first, significant variations of arc structure and light emitting were observed under different conditions. A thin outer burning layer of vapor generated from electrodes with orange light was found due to the extremely high arc temperature. Second, with the increasing electrode gap in discharging, the arc power was shown to have a non monotonic relationship with arc length for constant initial circuit voltage and resistance. Finally, the temperature rises of electrode surface caused by heat transfer from arc were found to be not sensitive with increasing arc length due to special heat transfer mechanism. In addition, temperature of ambient air showed a large gradient in radial direction of arc.

Enhanced emotional empathy after psychosocial stress in young healthy men.

PubMed

Wolf, Oliver T; Schulte, Judith M; Drimalla, Hanna; Hamacher-Dang, Tanja C; Knoch, Daria; Dziobek, Isabel

2015-01-01

Empathy is a core prerequisite for human social behavior. Relatively, little is known about how empathy is influenced by social stress and its associated neuroendocrine alterations. The current study was designed to test the impact of acute stress on emotional and cognitive empathy. Healthy male participants were exposed to a psychosocial laboratory stressor (trier social stress test, (TSST)) or a well-matched control condition (Placebo-TSST). Afterwards they participated in an empathy test measuring emotional and cognitive empathy (multifaceted empathy test, (MET)). Stress exposure caused an increase in negative affect, a rise in salivary alpha amylase and a rise in cortisol. Participants exposed to stress reported more emotional empathy in response to pictures displaying both positive and negative emotional social scenes. Cognitive empathy (emotion recognition) in contrast did not differ between the stress and the control group. The current findings provide initial evidence for enhanced emotional empathy after acute psychosocial stress.

Space-based Observational Constraints for 1-D Plume Rise Models

NASA Technical Reports Server (NTRS)

Martin, Maria Val; Kahn, Ralph A.; Logan, Jennifer A.; Paguam, Ronan; Wooster, Martin; Ichoku, Charles

2012-01-01

We use a space-based plume height climatology derived from observations made by the Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard the NASA Terra satellite to evaluate the ability of a plume-rise model currently embedded in several atmospheric chemical transport models (CTMs) to produce accurate smoke injection heights. We initialize the plume-rise model with assimilated meteorological fields from the NASA Goddard Earth Observing System and estimated fuel moisture content at the location and time of the MISR measurements. Fire properties that drive the plume-rise model are difficult to estimate and we test the model with four estimates for active fire area and four for total heat flux, obtained using empirical data and Moderate Resolution Imaging Spectroradiometer (MODIS) re radiative power (FRP) thermal anomalies available for each MISR plume. We show that the model is not able to reproduce the plume heights observed by MISR over the range of conditions studied (maximum r2 obtained in all configurations is 0.3). The model also fails to determine which plumes are in the free troposphere (according to MISR), key information needed for atmospheric models to simulate properly smoke dispersion. We conclude that embedding a plume-rise model using currently available re constraints in large-scale atmospheric studies remains a difficult proposition. However, we demonstrate the degree to which the fire dynamical heat flux (related to active fire area and sensible heat flux), and atmospheric stability structure influence plume rise, although other factors less well constrained (e.g., entrainment) may also be significant. Using atmospheric stability conditions, MODIS FRP, and MISR plume heights, we offer some constraints on the main physical factors that drive smoke plume rise. We find that smoke plumes reaching high altitudes are characterized by higher FRP and weaker atmospheric stability conditions than those at low altitude, which tend to remain confined below the BL, consistent with earlier results. We propose two simplified parameterizations for computing injection heights for fires in CTMs and discuss current challenges to representing plume injection heights in large scale atmospheric models.

Inductive current startup in large tokamaks with expanding minor radius and rf assist

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

Borowski, S.K.

1984-02-01

Auxiliary rf heating of electrons before and during the current-rise phase of a large tokamak, such as the Fusion Engineering Device (R = 4.8 m, a = 1.3 m, sigma = 1.6, B/sub T/ = 3.62 T), is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation, 1 to 2 MW of electron cyclotron resonance heating power at approx. 90 GHz is used to create a small volume of high conductivity plasma (T/sub e/ approx. = 100 eV, n/sub e/ approx. = 10/sup 19/ m/sup -3/) near themore » upper hybrid resonance (UHR) region. This plasma conditioning permits a small radius (a/sub 0/ approx. = 0.2 to 0.4 m) current channel to be established with a relatively low initial loop voltage (less than or equal to 25 V as opposed to approx. 100 V without rf assist). During the subsequent plasma expansion and current ramp phase, a combination of rf heating (up to 5 MW) and current profile control leads to a substantial savings in volt-seconds by: (1) minimizing the resistive flux consumption; and (2) maintaining the internal flux at or near the flat profile limit.« less

Water movement in glass bead porous media: 1. Experiments of capillary rise and hysteresis

NASA Astrophysics Data System (ADS)

Lu, T. X.; Biggar, J. W.; Nielsen, D. R.

1994-12-01

Experimental observations of capillary rise and hysteresis of water or ethanol in glass beads are presented to improve our understanding of those physical processes in porous media. The results provide evidence that capillary rise into porous media cannot be fully explained by a model of cylinders. They further demonstrate that the "Ink bottle" model does not provide an adequate explanation of hysteresis. Glass beads serving as a model for ideal soil are enclosed in a rectangular glass chamber model. A TV camera associated with a microscope was used to record the processes of capillary rise and drainage. It is clearly shown during capillary rise that the fluid exhibits a "jump" behavior at the neck of the pores in an initially dry profile or at the bottom of the water film in an initially wet profile. Under an initially dry condition, the jump initiates at the particle with smallest diameter. The jump process continues to higher elevations until at equilibrium the surface tensile force is balanced by the hydrostatic force. The wetting front at that time is readily observed as flat and saturated. Under an initially wet condition, capillary rise occurs as a water film thickening process associated with the jump process. Trapped air behind the wetting front renders the wetting front irregular and unsaturated. The capillary rise into an initially wet porous medium can be higher than that into an initially dry profile. During the drying process, large surface areas associated with the gas-liquid interface develop, allowing the porous medium to retain more water than during the wetting process at the same pressure. That mechanism explains better the hysteresis phenomenon in porous media in contrast to other mechanisms that now prevail.

Effects of sea-level rise and pumpage elimination on saltwater intrusion in the Hilton Head Island area, South Carolina, 2004-2104

USGS Publications Warehouse

Payne, Dorothy F.

2010-01-01

Saltwater intrusion of the Upper Floridan aquifer has been observed in the Hilton Head area, South Carolina since the late 1970s and currently affects freshwater supply. Rising sea level in the Hilton Head Island area may contribute to the occurrence of and affect the rate of saltwater intrusion into the Upper Floridan aquifer by increasing the hydraulic gradient and by inundating an increasing area with saltwater, which may then migrate downward into geologic units that presently contain freshwater. Rising sea level may offset any beneficial results from reductions in groundwater pumpage, and thus needs to be considered in groundwater-management decisions. A variable-density groundwater flow and transport model was modified from a previously existing model to simulate the effects of sea-level rise in the Hilton Head Island area. Specifically, the model was used to (1) simulate trends of saltwater intrusion from predevelopment to the present day (1885-2004) and evaluate the conceptual model, (2) project these trends from the present day into the future based on different potential rates of sea-level change, and (3) evaluate the relative influences of pumpage and sea-level rise on saltwater intrusion. Four scenarios were simulated for 2004-2104: (1) continuation of the estimated sea-level rise rate over the last century, (2) a doubling of the sea-level rise, (3) a cessation of sea-level rise, and (4) continuation of the rate over the last century coupled with an elimination of all pumpage. Results show that, if present-day (year 2004) pumping conditions are maintained, the extent of saltwater in the Upper Floridan aquifer will increase, whether or not sea level continues to rise. Furthermore, if all pumpage is eliminated and sea level continues to rise, the simulated saltwater extent in the Upper Floridan aquifer is reduced. These results indicate that pumpage is a strong driving force for simulated saltwater intrusion, more so than sea-level rise at current rates. However, results must be considered in light of limitations in the model, including, but not limited to uncertainty in field data, the conceptual model, the physical properties and representation of the hydrogeologic framework, and boundary and initial conditions, as well as uncertainty in future conditions, such as the rate of sea-level rise.

Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel.

PubMed

Razus, D; Brinzea, V; Mitu, M; Movileanu, C; Oancea, D

2011-06-15

The maximum rates of pressure rise during closed vessel explosions of propane-air mixtures are reported, for systems with various initial concentrations, pressures and temperatures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.3 bar; T(0)=298-423 K). Experiments were performed in a spherical vessel (Φ=10 cm) with central ignition. The deflagration (severity) index K(G), calculated from experimental values of maximum rates of pressure rise is examined against the adiabatic deflagration index, K(G, ad), computed from normal burning velocities and peak explosion pressures. At constant temperature and fuel/oxygen ratio, both the maximum rates of pressure rise and the deflagration indices are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, the maximum rates of pressure rise and deflagration indices are slightly influenced by the initial temperature; some influence of the initial temperature on maximum rates of pressure rise is observed only for propane-air mixtures far from stoichiometric composition. The differentiated temperature influence on the normal burning velocities and the peak explosion pressures might explain this behaviour. Copyright © 2011 Elsevier B.V. All rights reserved.

Inductive current startup in large tokamaks with expanding minor radius and RF assist

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

Borowski, S.K.

1983-01-01

Auxiliary RF heating of electrons before and during the current rise phase of a large tokamak, such as the Fusion Engineering Device, is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation, 1 to 2 MW of electron cyclotron resonance heating power at approx.90 GHz is used to create a small volume of high conductivity plasma (T/sub e/ approx. = 100 eV, n/sub e/ approx. = 10/sup 19/m/sup -3/) near the upper hybrid resonance (UHR) region. This plasma conditioning permits a small radius (a/sup 0/ approx.< 0.4 m)more » current channel to be established with a relatively low initial loop voltage (approx.< 25 V as opposed to approx.100 V without RF assist). During the subsequent plasma expansion and current ramp phase, additional RF power is introduced to reduce volt-second consumption due to plasma resistance. To study the preheating phase, a near classical particle and energy transport model is developed to estimate the electron heating efficiency in a currentless toroidal plasma. The model assumes that preferential electron heating at the UHR leads to the formation of an ambipolar sheath potential between the neutral plasma and the conducting vacuum vessel and limiter.« less

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

Current-limited electron beam injection

NASA Technical Reports Server (NTRS)

Stenzel, R. L.

1977-01-01

The injection of an electron beam into a weakly collisional, magnetized background plasma was investigated experimentally. The injected beam was energetic and cold, the background plasma was initially isothermal. Beam and plasma dimensions were so large that the system was considered unbounded. The temporal and spatial evolution of the beam-plasma system was dominated by collective effects. High-frequency electrostatic instabilities rapidly thermalized the beam and heated the background electrons. The injected beam current was balanced by a return current consisting of background electrons drifting toward the beam source. The drift between electrons and ions gave rise to an ion acoustic instability which developed into strong three-dimensional turbulence. It was shown that the injected beam current was limited by the return current which is approximately given by the electron saturation current. Non-Maxwellian electron distribution functions were observed.

Medicare privatization and the erosion of retirement security.

PubMed

Polivka, Larry; Kwak, Jung

2008-01-01

This paper describes initiatives to privatize the Medicare program over the last 10 years and the implications of these initiatives for the future of retirement security. Our analysis focuses on the privatization provisions of the Medicare Modernization Act, which is largely designed to benefit the corporate health care sector without containing costs or significantly reducing the threat of rising health care costs to the economic security of current and future retirees. In fact, as designed, the Medicare Modernization Act is likely to increase the threat to retirement security in the years ahead. We conclude with a series of policy alternatives to the neoliberal agenda for the privatization of Medicare.

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.

Adapting to Rising Sea Level: A Florida Perspective

NASA Astrophysics Data System (ADS)

Parkinson, Randall W.

2009-07-01

Global climate change and concomitant rising sea level will have a profound impact on Florida's coastal and marine systems. Sea-level rise will increase erosion of beaches, cause saltwater intrusion into water supplies, inundate coastal marshes and other important habitats, and make coastal property more vulnerable to erosion and flooding. Yet most coastal areas are currently managed under the premise that sea-level rise is not significant and the shorelines are static or can be fixed in place by engineering structures. The new reality of sea-level rise and extreme weather due to climate change requires a new style of planning and management to protect resources and reduce risk to humans. Scientists must: (1) assess existing coastal vulnerability to address short term management issues and (2) model future landscape change and develop sustainable plans to address long term planning and management issues. Furthermore, this information must be effectively transferred to planners, managers, and elected officials to ensure their decisions are based upon the best available information. While there is still some uncertainty regarding the details of rising sea level and climate change, development decisions are being made today which commit public and private investment in real estate and associated infrastructure. With a design life of 30 yrs to 75 yrs or more, many of these investments are on a collision course with rising sea level and the resulting impacts will be significant. In the near term, the utilization of engineering structures may be required, but these are not sustainable and must ultimately yield to "managed withdrawal" programs if higher sea-level elevations or rates of rise are forthcoming. As an initial step towards successful adaptation, coastal management and planning documents (i.e., comprehensive plans) must be revised to include reference to climate change and rising sea-level.

Kelvin probe microscopic visualization of charge storage at polystyrene interfaces with pentacene and gold

NASA Astrophysics Data System (ADS)

Dawidczyk, T. J.; Johns, G. L.; Ozgun, R.; Alley, O.; Andreou, A. G.; Markovic, N.; Katz, H. E.

2012-02-01

Charge carriers trapped in polystyrene (PS) were investigated with Kelvin probe microscopy (KPM) and thermally stimulated discharge current (TSDC). Lateral heterojunctions of pentacene/PS were scanned using KPM, effectively observing polarization along a side view of a lateral nonvolatile organic field-effect transistor dielectric interface. TSDC was used to observe charge migration out of PS films and to estimate the trap energy level inside the PS, using the initial rise method.

Dielectric relaxation behaviour of (poly (vinyl formal)) (PVFO) and polyvinylidenefluoride (PVDF) blends

NASA Astrophysics Data System (ADS)

Dawande, Kiran; Patel, Swarnim; Bajpai, Rakesh; Keller, J. M.

2018-05-01

Thermally stimulated discharge currents in PVFO: PVDF blend samples of weight percentage ratio 80:20 and 95:05 prepared by the solution cast technique have been studied as function of polarizing temperature. Three distinct peaks are found at 60±10, 100±10, and 140 ±10 °C respectively. Activation energy values been calculated by initial rise method and it were found to range from 0.22 to 1.0 eV.

Cenozoic seismic stratigraphy of the SW Bermuda Rise

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

Mountain, G.S.; Driscoll, N.W.; Miller, K.G.

1985-01-01

The seismic Horizon A-Complex (Tucholke, 1979) readily explains reflector patterns observed along the western third of the Bermuda Rise; farther east, basement is much more rugged and gravity flows shed from local topographic highs complicate the stratigraphy. Distal turbidites on the southwestern Bermuda Rise onlap reflector A* from the west, suggesting early Paleocene mass wasting of the North American margin. Locally erosive bottom currents cut into the middle Eocene section of the SW Bermuda Rise; these northward flowing currents preceded those that formed reflector Au along the North American margin near the Eocene-Oligocene boundary. Southward flowing currents swift enough tomore » erode the sea floor and to form reflector Au did not reach as far east as the SW Bermuda Rise. Instead, the main effect of these Au currents was to pirate sediment into contour-following geostrophic flows along the North American margin and to deprive the deep basin and the Bermuda Rise of sediment transported down-slope. Consequently, post-Eocene sediments away from the margin are fine-grained muds. Deposition of these muds on the SW Bermuda Rise was controlled by northward flowing bottom currents. The modern Hatteras Abyssal Plain developed in the late Neogene as turbidites once again onlapped the SW Bermuda Rise. Today, these deposits extend farthest east in fracture zone valleys and in the swales between sediment waves. Northward flowing currents continue at present to affect sediment distribution patterns along the western edge of the Bermuda Rise.« less

Convection currents in a water calorimeter.

PubMed

Schulz, R J; Weinhous, M S

1985-10-01

A flexible, temperature-regulated water calorimeter has been constructed containing two pairs of thermistor sensors at depths of 6.23 and 10.0 cm. It may be irradiated by vertical or horizontal beams, and operated at temperatures in the range from 3 to 40 degrees C. When irradiated at 30 degrees C with a vertically downward 19 MeV electron beam, the responses of the proximal and midline thermistors were in accordance with the depth-dose curve. When irradiated horizontally, the initial patterns of temperature rise were the same, but after about 30 s (4 Gy) the rate of temperature rise decreased at the proximal thermistors and increased at the midline thermistors. Shortly after irradiation, the temperature curve and increased at the midline thermistors. Shortly after irradiation, the temperature curve of the midline thermistors crossed that for the proximal thermistors, a pattern that suggested the presence of convection currents. To test this hypothesis, the calorimeter was operated at 4 degrees C. The temperature patterns for horizontal irradiation became the same as those obtained with vertical beams, thus demonstrating the production of convection currents in water at a temperature of 30 degrees C for temperature gradients as small as 10(-3) degrees C cm-1.

Prediction of burnout of a conduction-cooled BSCCO current lead

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

Seol, S.Y.; Cha, Y.S.; Niemann, R.C.

A one-dimensional heat conduction model is employed to predict burnout of a Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} current lead. The upper end of the lead is assumed to be at 77 K and the lower end is at 4 K. The results show that burnout always occurs at the warmer end of the lead. The lead reaches its burnout temperature in two distinct stage. Initially, the temperature rises slowly when part of the lead is in flux-flow state. As the local temperature reaches the critical temperature, it begins to increase sharply. Burnout time depends strongly on flux-flow resistivity.

Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux

NASA Technical Reports Server (NTRS)

Hasan, M. M.; Lin, C. S.; Vandresar, N. T.

1991-01-01

Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed.

The initial rise method extended to multiple trapping levels in thermoluminescent materials.

PubMed

Furetta, C; Guzmán, S; Ruiz, B; Cruz-Zaragoza, E

2011-02-01

The well known Initial Rise Method (IR) is commonly used to determine the activation energy when only one glow peak is presented and analysed in the phosphor materials. However, when the glow peak is more complex, a wide peak and some holders appear in the structure. The application of the Initial Rise Method is not valid because multiple trapping levels are considered and then the thermoluminescent analysis becomes difficult to perform. This paper shows the case of a complex glow curve structure as an example and shows that the calculation is also possible using the IR method. The aim of the paper is to extend the well known Initial Rise Method (IR) to the case of multiple trapping levels. The IR method is applied to minerals extracted from Nopal cactus and Oregano spices because the thermoluminescent glow curve's shape suggests a trap distribution instead of a single trapping level. Copyright © 2010 Elsevier Ltd. All rights reserved.

Thrombolytic therapy of right heart emboli-in-transit.

PubMed

Jessurun, G A; Brügemann, J; Hamer, J P; Römer, J P; Lie, K I

1995-11-01

Currently, no consensus exists for the appropriate treatment of echocardiographically diagnosed mobile right heart masses giving rise to a high suspicion of migrant thromboembolism in patients with pulmonary embolism. This may lead to unnecessary delay in the implementation of the most appropriate treatment for these patients. Several earlier studies have supported the beneficial role of thrombolytic therapy. We report on an additional two patients with mobile right heart thromboemboli, refractory to systemic anticoagulation, who recovered quickly after initiation of thrombolytic therapy.

Current and Future Challenges to Resourcing U.S. Navy Public Shipyards

DTIC Science & Technology

carriers. For this reason, the public shipyards are required to maintain core capabilities that the private sector does not maintain. In addition, they are ...has been on the rise. Direct man-days of work assigned to and executed by the shipyards have increased during that time and are planned to continue to...role in future workforce management as the initiatives are broadened. Planned increases in civilian staffing levels are necessary but not sufficient to mitigate near-term execution risk at the shipyards.

Targeting Cell Polarity Machinery to Exhaust Breast Cancer Stem Cells

DTIC Science & Technology

2017-10-01

resemble normal stem cells, specifically in the ability to infinitely give rise to the bulk of a tumor as the “seed” of the cancer, account for cancer...infinitely give rise to the bulk of a tumor as the “seed” of the cancer, account for cancer initiation, progression, recurrence, and chemo...cell population that can infinitely give rise to the bulk of a tumor as the “seed” of the cancer, account for cancer initiation, progression, radio

Impacts of past climate and sea level change on Everglades wetlands: placing a century of anthropogenic change into a late-Holocene context

USGS Publications Warehouse

Willard, D.A.; Bernhardt, C.E.

2011-01-01

We synthesize existing evidence on the ecological history of the Florida Everglades since its inception ~7 ka (calibrated kiloannum) and evaluate the relative impacts of sea level rise, climate variability, and human alteration of Everglades hydrology on wetland plant communities. Initial freshwater peat accumulation began between 6 and 7 ka on the platform underlying modern Florida Bay when sea level was ~6.2 m below its current position. By 5 ka, sawgrass and waterlily peats covered the area bounded by Lake Okeechobee to the north and the Florida Keys to the south. Slower rates of relative sea level rise ~3 ka stabilized the south Florida coastline and initiated transitions from freshwater to mangrove peats near the coast. Hydrologic changes in freshwater marshes also are indicated ~3 ka. During the last ~2 ka, the Everglades wetland was affected by a series of hydrologic fluctuations related to regional to global-scale fluctuations in climate and sea level. Pollen evidence indicates that regional-scale droughts lasting two to four centuries occurred ~1 ka and ~0.4 ka, altering wetland community composition and triggering development of characteristic Everglades habitats such as sawgrass ridges and tree islands. Intercalation of mangrove peats with estuarine muds ~1 ka indicates a temporary slowing or stillstand of sea level. Although sustained droughts and Holocene sea level rise played large roles in structuring the greater Everglades ecosystem, twentieth century reductions in freshwater flow, compartmentalization of the wetland, and accelerated rates of sea level rise had unprecedented impacts on oxidation and subsidence of organic soils, changes/loss of key Everglades habitats, and altered distribution of coastal vegetation.

Brain metastasis from squamous cell carcinoma of the head and neck: a review of the literature in the genomic era.

PubMed

Barrett, Thomas F; Gill, Corey M; Miles, Brett A; Iloreta, Alfred M C; Bakst, Richard L; Fowkes, Mary; Brastianos, Priscilla K; Bederson, Joshua B; Shrivastava, Raj K

2018-06-01

Squamous cell carcinoma of the head and neck (HNSCC) affects nearly 500,000 individuals globally each year. With the rise of human papillomavirus (HPV) in the general population, clinicians are seeing a concomitant rise in HPV-related HNSCC. Notably, a hallmark of HPV-related HNSCC is a predilection for unique biological and clinical features, which portend a tendency for hematogenous metastasis to distant locations, such as the brain. Despite the classic belief that HNSCC is restricted to local spread via passive lymphatic drainage, brain metastases (BMs) are a rare complication that occurs in less than 1% of all HNSCC cases. Time between initial diagnosis of HNSCC and BM development can vary considerably. Some patients experience more than a decade of disease-free survival, whereas others present with definitive neurological symptoms that precede primary tumor detection. The authors systematically review the current literature on HNSCC BMs and discuss the current understanding of the effect of HPV status on the risk of developing BMs in the modern genomic era.

Numerical Investigation of Magnetically Driven Isentropic Compression of Solid Aluminum Cylinders with a Semi-Analytical Code

NASA Astrophysics Data System (ADS)

Largent, Billy T.

The state of matter at extremely high pressures and densities is of fundamental interest to many branches of research, including planetary science, material science, condensed matter physics, and plasma physics. Matter with pressures, or energy densities, above 1 megabar (100 gigapascal) are defined as High Energy Density (HED) plasmas. They are directly relevant to the interiors of planets such as Earth and Jupiter and to the dense fuels in Inertial Confinement Fusion (ICF) experiments. To create HEDP conditions in laboratories, a sample may be compressed by a smoothly varying pressure ramp with minimal temperature increase, following the isentropic thermodynamic process. Isentropic compression of aluminum targets has been done using magnetic pressure produced by megaampere, pulsed power currents having 100 ns rise times. In this research project, magnetically driven, cylindrical isentropic compression has been numerically studied. In cylindrical geometry, material compression and pressure become higher than in planar geometry due to geometrical effects. Based on a semi-analytical model for the Magnetized Liner Inertial Fusion (MagLIF) concept, a code called "SA" was written to design cylindrical compression experiments on the 1.0 MA Zebra pulsed power generator at the Nevada Terawatt Facility (NTF). To test the physics models in the code, temporal progresses of rod compression and pressure were calculated with SA and compared with 1-D magnetohydrodynamic (MHD) codes. The MHD codes incorporated SESAME tables, for equation of state and resistivity, or the classical Spitzer model. A series of simulations were also run to find optimum rod diameters for 1.0 MA and 1.8 MA Zebra current pulses. For a 1.0 MA current peak and 95 ns rise time, a maximum compression of 2.35 ( 6.3 g/cm3) and a pressure of 900 GPa within a 100 mum radius were found for an initial diameter of 1.05 mm. For 1.8 MA peak simulations with the same rise time, the initial diameter of 1.3 mm was optimal with 3.32 ( 9.0 g/cm 3) compression.

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.

Axial magnetic field injection in magnetized liner inertial fusion

NASA Astrophysics Data System (ADS)

Gourdain, P.-A.; Adams, M. B.; Davies, J. R.; Seyler, C. E.

2017-10-01

MagLIF is a fusion concept using a Z-pinch implosion to reach thermonuclear fusion. In current experiments, the implosion is driven by the Z-machine using 19 MA of electrical current with a rise time of 100 ns. MagLIF requires an initial axial magnetic field of 30 T to reduce heat losses to the liner wall during compression and to confine alpha particles during fusion burn. This field is generated well before the current ramp starts and needs to penetrate the transmission lines of the pulsed-power generator, as well as the liner itself. Consequently, the axial field rise time must exceed hundreds of microseconds. Any coil capable of being submitted to such a field for that length of time is inevitably bulky. The space required to fit the coil near the liner, increases the inductance of the load. In turn, the total current delivered to the load decreases since the voltage is limited by driver design. Yet, the large amount of current provided by the Z-machine can be used to produce the required 30 T field by tilting the return current posts surrounding the liner, eliminating the need for a separate coil. However, the problem now is the field penetration time, across the liner wall. This paper discusses why skin effect arguments do not hold in the presence of resistivity gradients. Numerical simulations show that fields larger than 30 T can diffuse across the liner wall in less than 60 ns, demonstrating that external coils can be replaced by return current posts with optimal helicity.

Rf-assisted current startup in the Fusion Engineering Device (FED)

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

Borowski, S.K.; Peng, Y.K.M.; Kammash, T.

1982-08-01

Auxiliary rf heating of electrons before and during the current rise phase in the Fusion Engineering Device is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation 1 to 2 MW of electron cyclotron resonance heating (ECRH) power at approx. 90 GHz is used to create a small volume of high conductivity plasma (T/sub e/ approx. = 100 eV, n/sub e/ approx. = 10/sup 13/ cm/sup -3/) near the upper hybrid resonance (UHR) region. This plasma conditioning permits a small radius (a/sub o/ approx. = 0.2 to 0.4more » m) current channel to be established with a relatively low initial loop voltage (less than or equal to 25 V). During the subsequent plasma expansion and current ramp phase, additional rf power is introduced to reduce volt-second consumption due to plasma resistance. A near classical particle and energy transport model has been developed to estimate the efficiency of electron heating in a currentless toroidal plasma. The model assumes that preferential electron heating at the UHR leads to the formation of an ambipolar sheath potential between the neutral plasma and the conducting vacuum vessel and limiter. The ambipolar electric field (E/sub AMB/) enables the plasma to neutralize itself via poloidal E vector/sub AMB/ x B vector drift. This form of effective rotational transform short-circuits the vertical charge separation and improves particle confinement.« less

Sea-Level Projections from the SeaRISE Initiative

NASA Technical Reports Server (NTRS)

Nowicki, Sophie; Bindschadler, Robert

2011-01-01

SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

Conductivity Rise During Irreversible Electroporation: True Permeabilization or Heat?

PubMed

Ruarus, Alette H; Vroomen, Laurien G P H; Puijk, Robbert S; Scheffer, Hester J; Faes, Theo J C; Meijerink, Martijn R

2018-04-23

Irreversible electroporation (IRE) induces apoptosis with high-voltage electric pulses. Although the working mechanism is non-thermal, development of secondary Joule heating occurs. This study investigated whether the observed conductivity rise during IRE is caused by increased cellular permeabilization or heat development. IRE was performed in a gelatin tissue phantom, in potato tubers, and in 30 patients with unresectable colorectal liver metastases (CRLM). Continuous versus sequential pulsing protocols (10-90 vs. 10-30-30-30) were assessed. Temperature was measured using fiber-optic probes. After temperature had returned to baseline, 100 additional pulses were delivered. The primary technique efficacy of the treated CRLM was compared to the periprocedural current rise. Seven patients received ten additional pulses after a 10-min cool-down period. Temperature and current rise was higher for the continuous pulsing protocol (medians, gel: 13.05 vs. 9.55 °C and 9 amperes (A) vs. 7A; potato: 12.70 vs. 10.53 °C and 6.0A vs. 6.5A). After cooling-down, current returned to baseline in the gel phantom and near baseline values (Δ2A with continuous- and Δ5A with sequential pulsing) in the potato tubers. The current declined after cooling-down in all seven patients with CRLM, although baseline values were not reached. There was a positive correlation between current rise and primary technique efficacy (p = 0.02); however, the previously reported current increase threshold of 12-15A was reached in 13%. The observed conductivity rise during IRE is caused by both cellular permeabilization and heat development. Although a correlation between current rise and efficacy exists, the current increase threshold seems unfeasible for CRLM.

Learning from Rising Sixth Grade Readers: How Nooks Shaped Students' Reading Behaviors during a Summer Independent Reading Initiative

ERIC Educational Resources Information Center

Mitchell, Chrystine Cooper

2016-01-01

Researchers have documented a "summer reading setback" where an achievement gap between proficient and struggling readers expands during the summer. This research focuses on 20 rising sixth graders who participated in a summer independent reading initiative using Nook digital readers. Using a qualitative exploratory design and content…

Decision-making Processes among Prostate Cancer Survivors with Rising PSA Levels: Results from a Qualitative Analysis.

PubMed

Shen, Megan Johnson; Nelson, Christian J; Peters, Ellen; Slovin, Susan F; Hall, Simon J; Hall, Matt; Herrera, Phapichaya Chaoprang; Leventhal, Elaine A; Leventhal, Howard; Diefenbach, Michael A

2015-05-01

Prostate cancer survivors with a rising prostate-specific antigen (PSA) level have few treatment options, experience a heightened state of uncertainty about their disease trajectory that might include the possibility of cancer metastasis and death, and often experience elevated levels of distress as they have to deal with a disease they thought they had conquered. Guided by self-regulation theory, the present study examined the cognitive and affective processes involved in shared decision making between physicians and patients who experience a rising PSA after definitive treatment for prostate cancer. In-depth interviews were conducted with 34 prostate cancer survivors who had been diagnosed with a rising PSA (i.e., biochemical failure) within the past 12 months. Survivors were asked about their experiences and affective responses after being diagnosed with a rising PSA and while weighing potential treatment options. In addition, patients were asked about their decision-making process for the initial prostate cancer treatment. Compared with the initial diagnosis, survivors with a rising PSA reported increased negative affect following their diagnosis, concern about the treatability of their disease, increased planning and health behavior change, heightened levels of worry preceding doctor appointments (especially prior to the discussion of PSA testing results), and a strong reliance on physicians' treatment recommendations. Prostate cancer survivors' decision-making processes for the treatment of a rising PSA are markedly different from those of the initial diagnosis of prostate cancer. Because patients experience heightened distress and rely more heavily on their physicians' recommendations with a rising PSA, interactions with the health care provider provide an excellent opportunity to address and assist patients with managing the uncertainty and distress inherent with rising PSA levels. © The Author(s) 2014.

Collapse of the West Antarctic Ice Sheet after local destabilization of the Amundsen Basin

PubMed Central

Feldmann, Johannes; Levermann, Anders

2015-01-01

The future evolution of the Antarctic Ice Sheet represents the largest uncertainty in sea-level projections of this and upcoming centuries. Recently, satellite observations and high-resolution simulations have suggested the initiation of an ice-sheet instability in the Amundsen Sea sector of West Antarctica, caused by the last decades’ enhanced basal ice-shelf melting. Whether this localized destabilization will yield a full discharge of marine ice from West Antarctica, associated with a global sea-level rise of more than 3 m, or whether the ice loss is limited by ice dynamics and topographic features, is unclear. Here we show that in the Parallel Ice Sheet Model, a local destabilization causes a complete disintegration of the marine ice in West Antarctica. In our simulations, at 5-km horizontal resolution, the region disequilibrates after 60 y of currently observed melt rates. Thereafter, the marine ice-sheet instability fully unfolds and is not halted by topographic features. In fact, the ice loss in Amundsen Sea sector shifts the catchment's ice divide toward the Filchner–Ronne and Ross ice shelves, which initiates grounding-line retreat there. Our simulations suggest that if a destabilization of Amundsen Sea sector has indeed been initiated, Antarctica will irrevocably contribute at least 3 m to global sea-level rise during the coming centuries to millennia. PMID:26578762

Algorithm for evaluating the effectiveness of a high-rise development project based on current yield

NASA Astrophysics Data System (ADS)

Soboleva, Elena

2018-03-01

The article is aimed at the issues of operational evaluation of development project efficiency in high-rise construction under the current economic conditions in Russia. The author touches the following issues: problems of implementing development projects, the influence of the operational evaluation quality of high-rise construction projects on general efficiency, assessing the influence of the project's external environment on the effectiveness of project activities under crisis conditions and the quality of project management. The article proposes the algorithm and the methodological approach to the quality management of the developer project efficiency based on operational evaluation of the current yield efficiency. The methodology for calculating the current efficiency of a development project for high-rise construction has been updated.

The influence of wave energy and sediment transport on seagrass distribution

USGS Publications Warehouse

Stevens, Andrew W.; Lacy, Jessica R.

2012-01-01

A coupled hydrodynamic and sediment transport model (Delft3D) was used to simulate the water levels, waves, and currents associated with a seagrass (Zostera marina) landscape along a 4-km stretch of coast in Puget Sound, WA, USA. A hydroacoustic survey of seagrass percent cover and nearshore bathymetry was conducted, and sediment grain size was sampled at 53 locations. Wave energy is a primary factor controlling seagrass distribution at the site, accounting for 73% of the variability in seagrass minimum depth and 86% of the variability in percent cover along the shallow, sandy portions of the coast. A combination of numerical simulations and a conceptual model of the effect of sea-level rise on the cross-shore distribution of seagrass indicates that the area of seagrass habitat may initially increase and that wave dynamics are an important factor to consider in predicting the effect of sea-level rise on seagrass distributions in wave-exposed areas.

Experimental studies of the overshoot and undershoot in pulse-modulated radio-frequency atmospheric discharge

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

Huo, W. G.; Li, R. M.; Shi, J. J.

The overshoot and undershoot of the applied voltage on the electrodes, the discharge current, and radio frequency (RF) power were observed at the initial phase of pulse-modulated (PM) RF atmospheric pressure discharges, but factors influencing the overshoot and undershoot have not been fully elucidated. In this paper, the experimental studies were performed to seek the reasons for the overshoot and undershoot. The experimental results show that the overshoot and undershoot are associated with the pulse frequency, the rise time of pulse signal, and the series capacitor C{sub s} in the inversely L-shaped matching network. In the case of a highmore » RF power discharge, these overshoot and undershoot become serious when shortening the rise time of a pulse signal (5 ns) or operating at a moderate pulse frequency (500 Hz or 1 kHz).« less

Commutated automatic gain control system

NASA Technical Reports Server (NTRS)

Yost, S. R.

1982-01-01

The commutated automatic gain control (AGC) system was designed and built for the prototype Loran-C receiver is discussed. The current version of the prototype receiver, the Mini L-80, was tested initially in 1980. The receiver uses a super jolt microcomputer to control a memory aided phase loop (MAPLL). The microcomputer also controls the input/output, latitude/longitude conversion, and the recently added AGC system. The AGC control adjusts the level of each station signal, such that the early portion of each envelope rise is about at the same amplitude in the receiver envelope detector.

Nanosecond repetitively pulsed discharges in air at atmospheric pressure—the spark regime

NASA Astrophysics Data System (ADS)

Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

2010-12-01

Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 1015 cm-3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 1011 cm-3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 108 cm-3.

Formation of costs of high-rise objects of housing and civil purpose based on enlarged norms

NASA Astrophysics Data System (ADS)

Vorotyntseva, Anna; Ovsiannikov, Andrei; Bolgov, Vladimir

2018-03-01

When determining the cost of capital construction objects, for purposes of pre-design workings out and purposes of initial maximum initial price determination on tenders, construction price norms are used (CPNs). Modern CPNs are not designed to determine the value of high-rise buildings. It is necessary to adapt modern CPNs to get opportunity for the possibility to take into account special cost factors in determining the cost of high-rise buildings. The main ways can be: selection of new representative objects or application of additional correction factors.

Hypotonic Shock Modulates Na+ Current via a Cl- and Ca2+/Calmodulin Dependent Mechanism in Alveolar Epithelial Cells

PubMed Central

Tatur, Sabina; Brochiero, Emmanuelle; Grygorczyk, Ryszard; Berthiaume, Yves

2013-01-01

Alveolar epithelial cells are involved in Na+ absorption via the epithelial Na+ channel (ENaC), an important process for maintaining an appropriate volume of liquid lining the respiratory epithelium and for lung oedema clearance. Here, we investigated how a 20% hypotonic shock modulates the ionic current in these cells. Polarized alveolar epithelial cells isolated from rat lungs were cultured on permeant filters and their electrophysiological properties recorded. A 20% bilateral hypotonic shock induced an immediate, but transient 52% rise in total transepithelial current and a 67% increase in the amiloride-sensitive current mediated by ENaC. Amiloride pre-treatment decreased the current rise after hypotonic shock, showing that ENaC current is involved in this response. Since Cl- transport is modulated by hypotonic shock, its contribution to the basal and hypotonic-induced transepithelial current was also assessed. Apical NPPB, a broad Cl- channel inhibitor and basolateral DIOA a potassium chloride co-transporter (KCC) inhibitor reduced the total and ENaC currents, showing that transcellular Cl- transport plays a major role in that process. During hypotonic shock, a basolateral Cl- influx, partly inhibited by NPPB is essential for the hypotonic-induced current rise. Hypotonic shock promoted apical ATP secretion and increased intracellular Ca2+. While apyrase, an ATP scavenger, did not inhibit the hypotonic shock current response, W7 a calmodulin antagonist completely prevented the hypotonic current rise. These results indicate that a basolateral Cl- influx as well as Ca2+/calmodulin, but not ATP, are involved in the acute transepithelial current rise elicited by hypotonic shock. PMID:24019969

Meiosis, unreduced gametes, and parthenogenesis: implications for engineering clonal seed formation in crops.

PubMed

Ronceret, Arnaud; Vielle-Calzada, Jean-Philippe

2015-06-01

Meiosis and unreduced gametes. Sexual flowering plants produce meiotically derived cells that give rise to the male and female haploid gametophytic phase. In the ovule, usually a single precursor (the megaspore mother cell) undergoes meiosis to form four haploid megaspores; however, numerous mutants result in the formation of unreduced gametes, sometimes showing female specificity, a phenomenon reminiscent of the initiation of gametophytic apomixis. Here, we review the developmental events that occur during female meiosis and megasporogenesis at the light of current possibilities to engineer unreduced gamete formation. We also provide an overview of the current understanding of mechanisms leading to parthenogenesis and discuss some of the conceptual implications for attempting the induction of clonal seed production in cultivated plants.

Method and apparatus for producing co-current fluid contact

DOEpatents

Trutna, William R.

1997-01-01

An improved packing system and method are disclosed wherein a packing section includes a liquid distributor and a separator placed above the distributor so that gas rising through the liquid distributor contacts liquid in the distributor, forming a gas-liquid combination which rises in co-current flow to the separator. Liquid is collected in the separator, from which gas rises.

Method and apparatus for producing co-current fluid contact

DOEpatents

Trutna, W.R.

1997-12-09

An improved packing system and method are disclosed wherein a packing section includes a liquid distributor and a separator placed above the distributor so that gas rising through the liquid distributor contacts liquid in the distributor, forming a gas-liquid combination which rises in co-current flow to the separator. Liquid is collected in the separator, from which gas rises. 13 figs.

Rapidly Rising Optical Transients from the Birth of Binary Neutron Stars

NASA Astrophysics Data System (ADS)

Hotokezaka, Kenta; Kashiyama, Kazumi; Murase, Kohta

2017-11-01

We study optical counterparts of a new-born pulsar in a double neutron star system like PSR J0737-3039A/B. This system is believed to have ejected a small amount of mass of { O }(0.1 {M}⊙ ) at the second core-collapse supernova. We argue that the initial spin of the new-born pulsar can be determined by the orbital period at the time when the second supernova occurs. The spin angular momentum of the progenitor is expected to be similar to that of the He-burning core, which is tidally synchronized with the orbital motion, and then the second remnant may be born as a millisecond pulsar. If the dipole magnetic field strength of the nascent pulsar is comparable with that inferred from the current spin-down rate of PSR J0737-3039B, the initial spin-down luminosity is comparable to the luminosity of super-luminous supernovae. We consider thermal emission arising from the supernova ejecta driven by the relativistic wind from such a new-born pulsar. The resulting optical light curves have a rise time of ˜10 days and a peak luminosity of ˜1044 erg s-1. The optical emission may last for a month to several months, due to the reprocessing of X-rays and UV photons via photoelectric absorption. These features are broadly consistent with those of the rapidly rising optical transients. The high spin-down luminosity and small ejecta mass are favorable for the progenitor of the repeating fast radio burst, FRB 121102. We discuss a possible connection between new-born double pulsars and fast radio bursts.

Modeling the Effects of E-cigarettes on Smoking Behavior: Implications for Future Adult Smoking Prevalence.

PubMed

Cherng, Sarah T; Tam, Jamie; Christine, Paul J; Meza, Rafael

2016-11-01

Electronic cigarette (e-cigarette) use has increased rapidly in recent years. Given the unknown effects of e-cigarette use on cigarette smoking behaviors, e-cigarette regulation has become the subject of considerable controversy. In the absence of longitudinal data documenting the long-term effects of e-cigarette use on smoking behavior and population smoking outcomes, computational models can guide future empirical research and provide insights into the possible effects of e-cigarette use on smoking prevalence over time. Agent-based model examining hypothetical scenarios of e-cigarette use by smoking status and e-cigarette effects on smoking initiation and smoking cessation. If e-cigarettes increase individual-level smoking cessation probabilities by 20%, the model estimates a 6% reduction in smoking prevalence by 2060 compared with baseline model (no effects) outcomes. In contrast, e-cigarette use prevalence among never smokers would have to rise dramatically from current estimates, with e-cigarettes increasing smoking initiation by more than 200% relative to baseline model estimates to achieve a corresponding 6% increase in smoking prevalence by 2060. Based on current knowledge of the patterns of e-cigarette use by smoking status and the heavy concentration of e-cigarette use among current smokers, the simulated effects of e-cigarettes on smoking cessation generate substantially larger changes to smoking prevalence compared with their effects on smoking initiation.

Modeling the Effects of E-Cigarettes on Smoking Behavior: Implications for Future Adult Smoking Prevalence

PubMed Central

Cherng, Sarah T.; Tam, Jamie; Christine, Paul; Meza, Rafael

2016-01-01

Background Electronic cigarette (e-cigarette) use has increased rapidly in recent years. Given the unknown effects of e-cigarette use on cigarette smoking behaviors, e-cigarette regulation has become the subject of considerable controversy. In the absence of longitudinal data documenting the long-term effects of e-cigarette use on smoking behavior and population smoking outcomes, computational models can guide future empirical research and provide insights into the possible effects of e-cigarette use on smoking prevalence over time. Methods Agent-based model examining hypothetical scenarios of e-cigarette use by smoking status and e-cigarette effects on smoking initiation and smoking cessation. Results If e-cigarettes increase individual-level smoking cessation probabilities by 20%, the model estimates a 6% reduction in smoking prevalence by 2060 compared to baseline model (no effects) outcomes. In contrast, e-cigarette use prevalence among never smokers would have to rise dramatically from current estimates, with e-cigarettes increasing smoking initiation by more than 200% relative to baseline model estimates in order to achieve a corresponding 6% increase in smoking prevalence by 2060. Conclusions Based on current knowledge of the patterns of e-cigarette use by smoking status and the heavy concentration of e-cigarette use among current smokers, the simulated effects of e-cigarettes on smoking cessation generate substantially larger changes to smoking prevalence relative to their effects on smoking initiation. PMID:27093020

Effects of Droplet Size on Intrusion of Sub-Surface Oil Spills

NASA Astrophysics Data System (ADS)

Adams, Eric; Chan, Godine; Wang, Dayang

2014-11-01

We explore effects of droplet size on droplet intrusion and transport in sub-surface oil spills. Negatively buoyant glass beads released continuously to a stratified ambient simulate oil droplets in a rising multiphase plume, and distributions of settled beads are used to infer signatures of surfacing oil. Initial tests used quiescent conditions, while ongoing tests simulate currents by towing the source and a bottom sled. Without current, deposited beads have a Gaussian distribution, with variance increasing with decreasing particle size. Distributions agree with a model assuming first order particle loss from an intrusion layer of constant thickness, and empirically determined flow rate. With current, deposited beads display a parabolic distribution similar to that expected from a source in uniform flow; we are currently comparing observed distributions with similar analytical models. Because chemical dispersants have been used to reduce oil droplet size, our study provides one measure of their effectiveness. Results are applied to conditions from the `Deep Spill' field experiment, and the recent Deepwater Horizon oil spill, and are being used to provide ``inner boundary conditions'' for subsequent far field modeling of these events. This research was made possible by grants from Chevron Energy Technology Co., through the Chevron-MITEI University Partnership Program, and BP/The Gulf of Mexico Research Initiative, GISR.

Intermittent Reconnection Downflow Enhancements In A Simulated Flux Rope Eruption

NASA Astrophysics Data System (ADS)

Kliem, Bernhard; Linton, M. G.

2009-05-01

Supra-arcade downflows in X-ray and EUV flare emissions and post-eruption inflows in coronagraph data have been interpreted to be signatures of the downward reconnection outflow from a vertical (flare) current sheet. These downflows show an intermittent occurrence pattern, indicating that the reconnection is bursty in time or patchy in space, or both. We present MHD simulations of such reconnection in the realistic configuration of a vertical current sheet formed beneath and driven by an erupting flux rope. The reconnection is found to develop bursty outflows, both upward and downward, with the upward outflows generally showing the stronger variablity. While the reconnection starts early in the rise of the flux rope and its peak upward outflow velocity is closely correlated with the rope's rise velocity, the burstiness develops in a clear fashion only as the rope's height has increased from the initial position by about an order of magnitude, so that the current sheet has reached a sufficient vertical extent. The reconnection downflow shows a series of enhancements, each of them starting at a successively greater height from a newly developed magnetic X line. The plasma temporarily accelerated downward in such an enhancement soon turns into a gradual deceleration and then eventually comes to rest on top of previously accelerated plasma. These findings are consistent with the observations of intermittent downflows.

Variation in light intensity with height and time from subsequent lightning return strokes

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

Jordan, D.M.; Uman, M.A.

1983-08-20

Relative light intensity has been measured photographically as a function of height and time for seven subsequent return strokes in two lightning flashes at ranges of 7.8 and 8.7 km. The film used was Kodak 5474 Shellburst, which has a roughly constant spectral response between 300 and 670 nm. The time resolution was about 1.0 ..mu..s, and the spatial resolution was about 4 m. The observed light signals consisted of a fast rise to peak, followed by a slower decrease to a relatively constant value. The amplitude of the initial light peak decreases exponentially with height with a decay constantmore » of about 0.6 to 0.8 km. The 20% to 80% rise time of the initial light signal is between 1 and 4 ..mu..s near ground and increases by an additional 1 to 2 ..mu..s by the time the return stroke reaches the cloud base, a height between 1 and 2 km. The light intensity 30 ..mu..s after the initial peak is relatively constant with height and has an amplitude that is 15% to 30% of the initial peak near the ground and 50% to 100% of the initial peak at cloud base. The logarithm of the peak light intensity near the ground is roughly proportional to the initial peak electric field intensity, and this in turn implies that the current decrease with height may be much slower than the light decrease. The absolute light intensity has been estimated by integrating the photographic signals from individual channel segments to simulate the calibrated all-sky photoelectric data of Guo and Krider (1982). Using this method, the authors find that the mean peak radiance near the ground is 8.3 x 10/sup 5/ W/m, with a total range from 1.4 x 10/sup 5/ to 3.8 x 10/sup 6/ W/m. 16 references, 11 figures.« less

The effect of beam-driven return current instability on solar hard X-ray bursts

NASA Technical Reports Server (NTRS)

Cromwell, D.; Mcquillan, P.; Brown, J. C.

1986-01-01

The problem of electrostatic wave generation by a return current driven by a small area electron beam during solar hard X-ray bursts is discussed. The marginal stability method is used to solve numerically the electron and ion heating equations for a prescribed beam current evolution. When ion-acoustic waves are considered, the method appears satisfactory and, following an initial phase of Coulomb resistivity in which T sub e/T sub i rise, predicts a rapid heating of substantial plasma volumes by anomalous ohmic dissipation. This hot plasma emits so much thermal bremsstrahlung that, contrary to previous expectations, the unstable beam-plasma system actually emits more hard X-rays than does the beam in the purely collisional thick target regime relevant to larger injection areas. Inclusion of ion-cyclotron waves results in ion-acoustic wave onset at lower T sub e/T sub i and a marginal stability treatment yields unphysical results.

[Biochemical failure after curative treatment for localized prostate cancer].

PubMed

Zouhair, Abderrahim; Jichlinski, Patrice; Mirimanoff, René-Olivier

2005-12-07

Biochemical failure after curative treatment for localized prostate cancer is frequent. The diagnosis of biochemical failure is clear when PSA levels rise after radical prostatectomy, but may be more difficult after external beam radiation therapy. The main difficulty once biochemical failure is diagnosed is to distinguish between local and distant failure, given the low sensitivity of standard work-up exams. Metabolic imaging techniques currently under evaluation may in the future help us to localize the site of failures. There are several therapeutic options depending on the initial curative treatment, each with morbidity risks that should be considered in multidisciplinary decision-making.

Na+ current in presynaptic terminals of the crayfish opener cannot initiate action potentials.

PubMed

Lin, Jen-Wei

2016-01-01

Action potential (AP) propagation in presynaptic axons of the crayfish opener neuromuscular junction (NMJ) was investigated by simultaneously recording from a terminal varicosity and a proximal branch. Although orthodromically conducting APs could be recorded in terminals with amplitudes up to 70 mV, depolarizing steps in terminals to -20 mV or higher failed to fire APs. Patch-clamp recordings did detect Na(+) current (INa) in most terminals. The INa exhibited a high threshold and fast activation rate. Local perfusion of Na(+)-free saline showed that terminal INa contributed to AP waveform by slightly accelerating the rising phase and increasing the peak amplitude. These findings suggest that terminal INa functions to "touch up" but not to generate APs. Copyright © 2016 the American Physiological Society.

Exploring the cause of initially reactive bovine brains on rapid tests for BSE

PubMed Central

Dudas, Sandor; James, Jace; Anderson, Renee; Czub, Stefanie

2015-01-01

ABSTRACT Bovine spongiform encephalopathy (BSE) is an invariably fatal prion disease of cattle. The identification of the zoonotic potential of BSE prompted safety officials to initiate surveillance testing for this disease. In Canada, BSE surveillance is primarily focused on high risk cattle including animals which are dead, down and unable to rise, diseased or distressed. This targeted surveillance results in the submission of brain samples with a wide range of tissue autolysis and associated contaminants. These contaminants have the potential to interfere with important steps of surveillance tests resulting in initially positive test results requiring additional testing to confirm the disease status of the animal. The current tests used for BSE screening in Canada utilize the relative protease resistance of the prion protein gained when it misfolds from PrPC to PrPSc as part of the disease process. Proteinase K completely digests PrPC in normal brains, but leaves most of the PrPSc in BSE positive brains intact which is detected using anti-prion antibodies. These tests are highly reliable but occasionally give rise to initially reactive/false positive results. Test results for these reactive samples were close to the positive/negative cut-off on a sub set of test platforms. This is in contrast to all of the previous Canadian positive samples whose numeric values on these same test platforms were 10 to 100 fold greater than the test positive/negative cut-off. Here we explore the potential reason why a sample is repeatedly positive on a sub-set of rapid surveillance tests, but negative on other test platforms. In order to better understand and identify what might cause these initial reactions, we have conducted a variety of rapid and confirmatory assays as well as bacterial isolation and identification on BSE positive, negative and initially reactive samples. We observed high levels of viable bacterial contamination in initially reactive samples suggesting that the reactivity may be related to bacterial factors. Several bacteria isolated from the initially reactive samples have characteristics of biofilm forming bacteria and this extracellular matrix might play a role in preventing complete digestion of PrPC in these samples. PMID:26689488

46 CFR 164.008-4 - Test requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... thermocouples on the unexposed surface described in § 164.008-3(f)(2) will not rise more than 139 °C. (250 °F..., rise more than 225 °C. (405 °F.) above the initial temperature at the end of 15 minutes. When failure is due to excessive temperature rise on the joint, consideration will be given to alternate joint...

46 CFR 164.008-4 - Test requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... thermocouples on the unexposed surface described in § 164.008-3(f)(2) will not rise more than 139 °C. (250 °F..., rise more than 225 °C. (405 °F.) above the initial temperature at the end of 15 minutes. When failure is due to excessive temperature rise on the joint, consideration will be given to alternate joint...

Coping with Higher Sea Levels and Increased Coastal Flooding in New York City. Chapter 13

NASA Technical Reports Server (NTRS)

Gornitz, Vivien; Horton, Radley; Bader, Daniel A.; Orton, Philip; Rosenzweig, Cynthia

2017-01-01

The 837 km New York City shoreline is lined by significant economic assets and dense population vulnerable to sea level rise and coastal flooding. After Hurricane Sandy in 2012, New York City developed a comprehensive plan to mitigate future climate risks, drawing upon the scientific expertise of the New York City Panel on Climate Change (NPCC), a special advisory group comprised of university and private-sector experts. This paper highlights current NPCC findings regarding sea level rise and coastal flooding, with some of the City's ongoing and planned responses. Twentieth century sea level rise in New York City (2.8 cm/decade) exceeded the global average (1.7 cm/decade), underscoring the enhanced regional risk to coastal hazards. NPCC (2015) projects future sea level rise at the Battery of 28 - 53 cm by the 2050s and 46 - 99 cm by the 2080s, relative to 2000 - 2004 (mid-range, 25th - 75th percentile). High-end SLR estimates (90th percentile) reach 76 cm by the 2050s, and 1.9 m by 2100. Combining these projections with updated FEMA flood return period curves, assuming static flood dynamics and storm behavior, flood heights for the 100-year storm (excluding waves) attain 3.9-4.5 m (mid-range), relative to the NAVD88 tidal datum, and 4.9 m (high end) by the 2080s, up from 3.4 m in the 2000s. Flood heights with a 1% annual chance of occurrence in the 2000s increase to 2.0 - 5.4% (mid-range) and 12.7% per year (high-end), by the 2080s. Guided by NPCC (2013, 2015) findings, New York City has embarked on a suite of initiatives to strengthen coastal defenses, employing various approaches tailored to specific neighborhood needs. NPCC continues its collaboration with the city to investigate vulnerability to extreme climate events, including heat waves, inland floods and coastal storms. Current research entails higher-resolution neighborhood-level coastal flood mapping, changes in storm characteristics, surge height interactions with sea level rise, and stronger engagement with stakeholders and community-based organizations.

Variability of electromagnetic signatures of lightning initiation observed in the West Mediterranean basin

NASA Astrophysics Data System (ADS)

Kolmasova, I.; Santolik, O.; Defer, E.; Stéphane, P.; Lan, R.; Uhlir, L.; Coquillat, S.; Lambert, D.; Pinty, J. P.; Prieur, S.

2016-12-01

Lightning discharges to ground often exhibit millisecond-scale surges in the continuing currents following return strokes, called M-components. Relatively little is known regarding the source of M-component charge and the mechanisms by which that charge is transferred to ground. In this work, we seek to directly address these questions by presenting correlated high-speed video and Lightning Mapping Array (LMA) observations of a bi-directional leader that resulted in an M-component occurring in a rocket-and-wire triggered lightning flash. The observed leader initiated in the decayed remnants of a positive leader channel that had traversed virgin air approximately 90 msec prior. Three-dimensional locations and speeds of the photographed bi-directional leader and M-component processes are calculated by mapping video images to the observed LMA channel geometry. Both ends of the bi-directional leader exhibited speeds on the order of 2 x106 m sec-1 over 570 meters of the visible channel. Propagation of the luminosity wave from the in-cloud leader to ground ( 8.8 km channel length) exhibited appreciable dispersion, with rise-times (10-90%) increasing from 330 to 410 μsec and pulse-widths (half-maximum) increasing from 380 to 810 μsec - the M-component current pulse measured at ground-level exhibited a rise-time of 290 μsec and a pulse-width of 770 μsec. Group velocities of the luminosity wave have been calculated as a function of frequency, increasing from 2 x107 to 6 x107 m sec-1 over the dominant signal bandwidth (DC to 2 kHz). Additionally, multiple waves of luminosity are observed within the in-cloud channel, indicating nuanced wave phenomena possibly associated with reflection from the end of the leader channel and attachment with the main lightning channel carrying continuing current to ground.

Onset of 2D magnetic reconnection in the solar photosphere, chromosphere, and corona

NASA Astrophysics Data System (ADS)

Snow, B.; Botha, G. J. J.; McLaughlin, J. A.; Hillier, A.

2018-01-01

Aims: We aim to investigate the onset of 2D time-dependent magnetic reconnection that is triggered using an external (non-local) velocity driver located away from, and perpendicular to, an equilibrium Harris current sheet. Previous studies have typically utilised an internal trigger to initiate reconnection, for example initial conditions centred on the current sheet. Here, an external driver allows for a more naturalistic trigger as well as the study of the earlier stages of the reconnection start-up process. Methods: Numerical simulations solving the compressible, resistive magnetohydrodynamic (MHD) equations were performed to investigate the reconnection onset within different atmospheric layers of the Sun, namely the corona, chromosphere and photosphere. Results: A reconnecting state is reached for all atmospheric heights considered, with the dominant physics being highly dependent on atmospheric conditions. The coronal case achieves a sharp rise in electric field (indicative of reconnection) for a range of velocity drivers. For the chromosphere, we find a larger velocity amplitude is required to trigger reconnection (compared to the corona). For the photospheric environment, the electric field is highly dependent on the inflow speed; a sharp increase in electric field is obtained only as the velocity entering the reconnection region approaches the Alfvén speed. Additionally, the role of ambipolar diffusion is investigated for the chromospheric case and we find that the ambipolar diffusion alters the structure of the current density in the inflow region. Conclusions: The rate at which flux enters the reconnection region is controlled by the inflow velocity. This determines all aspects of the reconnection start-up process, that is, the early onset of reconnection is dominated by the advection term in Ohm's law in all atmospheric layers. A lower plasma-β enhances reconnection and creates a large change in the electric field. A high plasma-β hinders the reconnection, yielding a sharp rise in the electric field only when the velocity flowing into the reconnection region approaches the local Alfvén speed.

Cinetica de oxidacion de polimeros conductores: poli-3,4- etilendioxitiofeno

NASA Astrophysics Data System (ADS)

Caballero Romero, Maria

Films of poly-3,4-ethylenedioxythiophene (PEDOT) perchlorate used as electrodes in liquid electrolytes incorporate anions and solvent during oxidation for charge and osmotic balance: the film swells. During reduction the film shrinks, closes its structure trapping counterions getting then rising conformational packed states by expulsion of counterions and solvent. Here by potential step from the same reduced initial state to the same oxidized final state the rate coefficient, the activation energy and reaction orders related to the counterion concentration in solution and to the concentration of active centers in the polymer film, were attained following the usual methodology used for chemical and electrochemical kinetics. Now the full methodology was repeated using different reduced-shrunk or reduced-conformational compacted initial states every time. Those initial states were attained by reduction of the oxidized film at rising cathodic potentials for the same reduction time each. Rising reduced and conformational compacted states give slower subsequent oxidation rates by potential step to the same anodic potential every time. The activation energy, the reaction coefficient and reaction orders change for rising conformational compacted initial states. Decreasing rate constants and increasing activation energies are obtained for the PEDOT oxidation from increasing conformational compacted initial states. The experimental activation energy presents two linear ranges as a function of the initial reduced-compacted state. Using as initial states for the oxidation open structures attained by reduction at low cathodic potentials, activation energies attained were constant: namely the chemical activation energy. Using as initial states for the oxidation deeper reduced, closed and packed conformational structures, the activation energy includes two components: the constant chemical energy plus the conformational energy required to relax the conformational structure generating free volume which allows the entrance of the balancing counterions required for the reaction. The conformational energy increases linearly as a function of the reduction-compaction potential. The kinetic magnitudes include conformational and structural information. The Chemical Kinetics becomes Structural (or conformational) Chemical Kinetics.

Impact of Inner Surface Perturbations on the Stability of Cylindrical Liner Implosion

NASA Astrophysics Data System (ADS)

Weis, Matthew; Peterson, Kyle; Hess, Mark; Lau, Y. Y.; Zhang, Peng; Gilgenbach, Ronald

2015-11-01

This paper studies the effects of initial perturbations on the inner liner surface (ILS) of an imploding cylindrical liner. In MagLIF, nonuniform preheat of the fuel could provide an additional source of spatial nonuniformity on the ILS. A blast wave generated by the laser preheat might trigger the Richtmyer-Meshkov instability (RM) on the ILS which then serves as another seed to the Rayleigh-Taylor instability (RT) during the stagnation (deceleration) phase of the implosion. Another scenario is that the shock initiated from the outer liner surface, during current rise, propagates inward and is reflected at the ILS. This reflected shock would carry the initial ILS perturbations which then serve as an additional seed for the magneto-RT (MRT) during the acceleration phase of the implosion. These potentially dangerous interactions are analyzed using the 2D HYDRA code. The effects of axial magnetic fields, of the initial surface roughness spectrum, and of gas fill or water fill (to examine deceleration phase RT) are studied. M. R. Weis was supported by the Sandia National Laboratories. This work was also supported by DoE Grant DE-SC0012328.

Stable plume rise in a shear layer.

PubMed

Overcamp, Thomas J

2007-03-01

Solutions are given for plume rise assuming a power-law wind speed profile in a stably stratified layer for point and finite sources with initial vertical momentum and buoyancy. For a constant wind speed, these solutions simplify to the conventional plume rise equations in a stable atmosphere. In a shear layer, the point of maximum rise occurs further downwind and is slightly lower compared with the plume rise with a constant wind speed equal to the wind speed at the top of the stack. If the predictions with shear are compared with predictions for an equivalent average wind speed over the depth of the plume, the plume rise with shear is higher than plume rise with an equivalent average wind speed.

Study of the water transportation characteristics of marsh saline soil in the Yellow River Delta.

PubMed

He, Fuhong; Pan, Yinghua; Tan, Lili; Zhang, Zhenhua; Li, Peng; Liu, Jia; Ji, Shuxin; Qin, Zhaohua; Shao, Hongbo; Song, Xueyan

2017-01-01

One-dimensional soil column water infiltration and capillary adsorption water tests were conducted in the laboratory to study the water transportation characteristics of marsh saline soil in the Yellow River Delta, providing a theoretical basis for the improvement, utilization and conservation of marsh saline soil. The results indicated the following: (1) For soils with different vegetation covers, the cumulative infiltration capacity increased with the depth of the soil layers. The initial infiltration rate of soils covered by Suaeda and Tamarix chinensis increased with depth of the soil layers, but that of bare soil decreased with soil depth. (2) The initial rate of capillary rise of soils with different vegetation covers showed an increasing trend from the surface toward the deeper layers, but this pattern with respect to soil depth was relatively weak. (3) The initial rates of capillary rise were lower than the initial infiltration rates, but infiltration rate decreased more rapidly than capillary water adsorption rate. (4) The two-parameter Kostiakov model can very well-simulate the changes in the infiltration and capillary rise rates of wetland saline soil. The model simulated the capillary rise rate better than it simulated the infiltration rate. (5) There were strong linear relationships between accumulative infiltration capacity, wetting front, accumulative capillary adsorbed water volume and capillary height. Copyright © 2016 Elsevier B.V. All rights reserved.

Prostate specific antigen velocity as a measure of the natural history of prostate cancer: defining a 'rapid riser' subset.

PubMed

Nam, R K; Klotz, L H; Jewett, M A; Danjoux, C; Trachtenberg, J

1998-01-01

To study the rate of change in prostate specific antigen (PSA velocity) in patients with prostate cancer initially managed by 'watchful waiting'. Serial PSA levels were determined in 141 patients with prostate cancer confirmed by biopsy, who were initially managed expectantly and enrolled between May 1990 and December 1995. Sixty-seven patients eventually underwent surgery (mean age 59 years) because they chose it (the decision for surgery was not based on PSA velocity). A cohort of 74 patients remained on 'watchful waiting' (mean age 69 years). Linear regression and logarithmic transformations were used to segregate those patients who showed a rapid rise, defined as a > 50% rise in PSA per year (or a doubling time of < 2 years) and designated 'rapid risers'. An initial analysis based on a minimum of two PSA values showed that 31% were rapid risers. Only 15% of patients with more than three serial PSA determinations over > or = 6 months showed a rapid rise in PSA level. There was no advantage of log-linear analysis over linear regression models. Three serial PSA determinations over > or = 6 months in patients with clinically localized prostate cancer identifies a subset (15%) of patients with a rapidly rising PSA level. Shorter PSA surveillance with fewer PSA values may falsely identify patients with rapid rises in PSA level. However, further follow-up is required to determine if a rapid rise in PSA level identifies a subset of patients with an aggressive biological phenotype who are either still curable or who have already progressed to incurability through metastatic disease.

Influence of configuration effects on multiple burst simulation testing

NASA Technical Reports Server (NTRS)

Emanuely, J. L.; Cantaloube, M.

1991-01-01

During the initial phase of a lightning strike attachment on an aircraft, fast current pulses (rise time approximately 100 ns, I(sub max) approximately few kA) were measured, which can create equipment upsets or disturbances. This threat, made of repetitive pulses and usually called 'multiple bursts', can be reproduced at the equipment interfaces assuming that the transfer function of the structure was determined. The normalized waveform H (10 kA - 100 ns rise time) is the reference for one of these pulses. The importance of the coaxial return path termination for the injection of the wave H is emphasized. According to the constitutive materials of the test bed, and the adaptation of the line, the natural oscillations of the structure and the internal coupling mechanisms can be modified. As a conclusion, various test configurations in relation with the nature of the test bed and the characteristics of the generator are detailed, for a more accurate ground simulation of the attachment phase.

Paleo-elevation and subsidence of ˜145Ma Shatsky Rise inferred from CO2 and H2O in fresh volcanic glass

NASA Astrophysics Data System (ADS)

Shimizu, Kenji; Shimizu, Nobumichi; Sano, Takashi; Matsubara, Noritaka; Sager, William

2013-12-01

Shatsky Rise, a large Mesozoic oceanic plateau in the northwest Pacific, consists of three massifs (Tamu, Ori, and Shirshov) that formed near a mid-ocean-ridge triple junction. Published depth estimates imply that Shatsky Rise has not subsided normally, like typical oceanic lithosphere. We estimated paleo-eruption depths of Shatsky Rise massifs on the basis of dissolved CO2 and H2O in volcanic glass and descriptions of cores recovered from five sites of Integrated Ocean Drilling Program Expedition 324. Initial maximum elevations of Shatsky Rise are estimated to be 2500-3500 m above the surrounding seafloor and the ensuing subsidence of Shatsky Rise is estimated to be 2600-3400 m. We did not observe the anomalously low subsidence that has been reported for both Shatsky Rise and the Ontong Java Plateau. Although we could not resolve whether Shatsky Rise originated from a hot mantle plume or non-plume fusible mantle, uplift and subsidence histories of Shatsky Rise for the both cases are constrained based on the subsidence trend from the center of Tamu Massif (˜2600 m) toward the flank of Ori Massif (˜3400 m). In the case of a hot mantle plume origin, Shatsky Rise may have formed on young (˜5 Ma) pre-existing oceanic crust with a total crustal thickness of ˜20 km. For this scenario, the center of Shatsky Rise is subsequently uplifted by later (prolonged) crustal growth, forming the observed ˜30 km thickness crust. For a non-plume origin, Shatsky Rise may have formed at the spreading ridge center as initially thick crust (˜30 km thickness), with later reduced subsidence caused by the emplacement of a buoyant mass-perhaps a refractory mantle residuum-beneath the center of Shatsky Rise.

Challenges in Projecting Sea Level Rise impacts on the Coastal Environment of South Florida (Invited)

NASA Astrophysics Data System (ADS)

Obeysekera, J.; Park, J.; Irizarry-Ortiz, M. M.; Barnes, J. A.; Trimble, P.; Said, W.

2010-12-01

Due to flat topography, a highly transmissive groundwater aquifer, and a growing population with the associated infrastructure, South Florida’s coastal environment is one of the most vulnerable areas to sea level rise. Current projections of sea level rise and the associated storm surges will have direct impacts on coastal beaches and infrastructure, flood protection, freshwater aquifers, and both the isolated and regional wetlands. Uncertainties in current projections have made it difficult for regional and local governments to develop adaptation strategies as such measures will depend heavily on the temporal and spatial patterns of sea level rise in the coming decades. We demonstrate the vulnerability of both the built and natural environments of the coastal region and present the current efforts to understand and predict the sea level rise estimate that management agencies could employ in planning of adaptation strategies. In particular, the potential vulnerabilities of the flood control system as well as the threat to the water supply wellfields in the coastal belt will be presented. In an effort to understand the historical variability of sea level rise, we present linkages to natural phenomena such as Atlantic Multi-Decadal Oscillation, and the analytical methods we have developed to provide probabilistic projections of both mean sea level rise and the extremes.

Breakdown in helium in high-voltage open discharge with subnanosecond current front rise

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

Schweigert, I. V., E-mail: ischweig@itam.nsc.ru; Alexandrov, A. L.; Bokhan, P. A.

Investigations of high-voltage open discharge in helium have shown a possibility of generation of current pulses with subnanosecond front rise, due to ultra-fast breakdown development. The open discharge is ignited between two planar cathodes with mesh anode in the middle between them. For gas pressure 6 Torr and 20 kV applied voltage, the rate of current rise reaches 500 A/(cm{sup 2} ns) for current density 200 A/cm{sup 2} and more. The time of breakdown development was measured for different helium pressures and a kinetic model of breakdown in open discharge is presented, based on elementary reactions for electrons, ions andmore » fast atoms. The model also includes various cathode emission processes due to cathode bombardment by ions, fast atoms, electrons and photons of resonant radiation with Doppler shift of frequency. It is shown, that the dominating emission processes depend on the evolution of the discharge voltage during the breakdown. In the simulations, two cases of voltage behavior were considered: (i) the voltage is kept constant during the breakdown; (ii) the voltage is reduced with the growth of current. For the first case, the exponentially growing current is maintained due to photoemission by the resonant photons with Doppler-shifted frequency. For the second case, the dominating factor of current growth is the secondary electron emission. In both cases, the subnanosecond rise of discharge current was obtained. Also the effect of gas pressure on breakdown development was considered. It was found that for 20 Torr gas pressure the time of current rise decreases to 0.1 ns, which is in agreement with experimental data.« less

The electrothermal conductance and heat capacity of black phosphorus

NASA Astrophysics Data System (ADS)

Sengupta, Parijat; Das, Saptarshi; Shi, Junxia

2018-03-01

We study a thermal gradient induced current (It h ) flow in potassium-doped two-dimensional anisotropic black phosphorus (BP) with semi-Dirac dispersion. The prototype device is a BP channel clamped between two contacts maintained at unequal temperatures. The choice of BP lies in the predicted efficient thermoelectric behaviour. A temperature-induced difference in the Fermi levels of the two contacts drives the current (typified by the electro-thermal conductance) which we calculate using the Landauer transport equation. The current shows an initial rise when the device is operated at lower temperatures. The rise stalls at progressively higher temperatures and Ith acquires a plateau-like flat profile indicating a competing effect between a larger number of transmission modes and a corresponding drop in the Fermi level difference between the contacts. The current is computed for both n- and p-type BP, and the difference thereof is attributed to the particle-hole asymmetry. The utility of such calculations lie in conversion of the heat produced in a miniaturized chip to useful thermopower via a prototypical Seebeck power generator. Unlike the flow of Ith that purportedly utilizes the additional removable heat in a nanoscale device heat, the ability of a material to maintain a steady temperature is reflected in its heat capacity through effective absorption of thermal energy. The heat capacity is formulated in this work for BP via a Sommerfeld expansion. In the concluding part, we draw a microscopic connection between the two seemingly disparate processes of heat removal and absorption by pinning down their origin to the underlying density of states. Finally, a qualitative analysis of a Carnot-like efficiency of the considered thermoelectric engine is performed drawing upon the previous results on thermal current and heat capacity.

Evidence of negative leaders which precede fast rise ICC pulses of upward

NASA Astrophysics Data System (ADS)

Yoshida, S.; Akita, M.; Morimoto, T.; Ushio, T.; Kawasaki, Z.; Wang, D.; Takagi, N.

2008-12-01

During winter thunderstorm season in Japan, a lightning observation campaign was conducted with using a VHF broadband digital interferometer (DITF), a capacitive antenna, and Rogowski coils to study the charge transfer mechanism associated with ICC pulses of upward lightning. All the detection systems recorded one upward negative lightning stroke hitting a lightning protection tower. The upward lightning consists of only the Initial Stage (IS) with one upward positive leader and six ICC pulses. The six ICC pulses are sub-classified clearly into two types according to current pulse shapes. The type 1 ICC pulses have a higher geometric mean (GM) current peak of 17 kA and a shorter GM 10-90% risetime of 8.9 μs, while the type 2 ICC pulses have a lower GM current peak of 0.34 kA and longer GM 10-90% risetime of 55 μs. The type 1 ICC pulses have the preceding negative leaders connecting to the channel of the continuing current, while the type 2 ICC pulses have no clear preceding negative leader. These negative leaders prior to the type 1 ICC pulses probably caused the current increases of the ICC pulses, which means that the negative leaders created the channels for the ICC pulses. The height of the space charge transferred by one of the type 1 ICC pulses was estimated about 700 m above sea level at most. This observation result is the first evidence to show explicitly the existence of the negative leaders prior to the fast rise ICC pulse. Furthermore, the result shows that space charge could exist at a low attitude such as 700 m above sea level. This fact is one of the reasons why upward lightning occurs even from rather low structures during winter thunderstorm season in Japan.

Megagauss-level magnetic field production in cm-scale auto-magnetizing helical liners pulsed to 500 kA in 125 ns

DOE PAGES

Shipley, Gabriel A.; Awe, Thomas James; Hutsel, Brian Thomas; ...

2018-05-03

We present Auto-magnetizing (AutoMag) liners [Slutz et al., Phys. Plasmas 24, 012704 (2017)] are designed to generate up to 100 T of axial magnetic field in the fuel for Magnetized Liner Inertial Fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] without the need for external field coils. AutoMag liners (cylindrical tubes) are composed of discrete metallic helical conduction paths separated by electrically insulating material. Initially, helical current in the AutoMag liner produces internal axial magnetic field during a long (100 to 300 ns) current prepulse with an average current rise rate dI/dt=5 kA/ns. After the cold fuel is magnetized,more » a rapidly rising current (200 kA/ns) generates a calculated electric field of 64 MV/m between the helices. Such field is sufficient to force dielectric breakdown of the insulating material after which liner current is reoriented from helical to predominantly axial which ceases the AutoMag axial magnetic field production mechanism and the z-pinch liner implodes. Proof of concept experiments have been executed on the Mykonos linear transformer driver to measure the axial field produced by a variety of AutoMag liners and to evaluate what physical processes drive dielectric breakdown. Lastly, a range of field strengths have been generated in various cm-scale liners in agreement with magnetic transient simulations including a measured field above 90 T at I = 350 kA. By varying the helical pitch angle, insulator material, and insulator geometry, favorable liner designs have been identified for which breakdown occurs under predictable and reproducible field conditions.« less

Megagauss-level magnetic field production in cm-scale auto-magnetizing helical liners pulsed to 500 kA in 125 ns

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

Shipley, Gabriel A.; Awe, Thomas James; Hutsel, Brian Thomas

We present Auto-magnetizing (AutoMag) liners [Slutz et al., Phys. Plasmas 24, 012704 (2017)] are designed to generate up to 100 T of axial magnetic field in the fuel for Magnetized Liner Inertial Fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] without the need for external field coils. AutoMag liners (cylindrical tubes) are composed of discrete metallic helical conduction paths separated by electrically insulating material. Initially, helical current in the AutoMag liner produces internal axial magnetic field during a long (100 to 300 ns) current prepulse with an average current rise rate dI/dt=5 kA/ns. After the cold fuel is magnetized,more » a rapidly rising current (200 kA/ns) generates a calculated electric field of 64 MV/m between the helices. Such field is sufficient to force dielectric breakdown of the insulating material after which liner current is reoriented from helical to predominantly axial which ceases the AutoMag axial magnetic field production mechanism and the z-pinch liner implodes. Proof of concept experiments have been executed on the Mykonos linear transformer driver to measure the axial field produced by a variety of AutoMag liners and to evaluate what physical processes drive dielectric breakdown. Lastly, a range of field strengths have been generated in various cm-scale liners in agreement with magnetic transient simulations including a measured field above 90 T at I = 350 kA. By varying the helical pitch angle, insulator material, and insulator geometry, favorable liner designs have been identified for which breakdown occurs under predictable and reproducible field conditions.« less

The electrothermal conductance and heat capacity of black phosphorus.

PubMed

Sengupta, Parijat; Das, Saptarshi; Shi, Junxia

2018-03-14

We study a thermal gradient induced current I th flow in potassium-doped two-dimensional anisotropic black phosphorus (BP) with semi-Dirac dispersion. The prototype device is a BP channel clamped between two contacts maintained at unequal temperatures. The choice of BP lies in the predicted efficient thermoelectric behaviour. A temperature-induced difference in the Fermi levels of the two contacts drives the current (typified by the electro-thermal conductance) which we calculate using the Landauer transport equation. The current shows an initial rise when the device is operated at lower temperatures. The rise stalls at progressively higher temperatures and I th acquires a plateau-like flat profile indicating a competing effect between a larger number of transmission modes and a corresponding drop in the Fermi level difference between the contacts. The current is computed for both n- and p-type BP, and the difference thereof is attributed to the particle-hole asymmetry. The utility of such calculations lie in conversion of the heat produced in a miniaturized chip to useful thermopower via a prototypical Seebeck power generator. Unlike the flow of I th that purportedly utilizes the additional removable heat in a nanoscale device heat, the ability of a material to maintain a steady temperature is reflected in its heat capacity through effective absorption of thermal energy. The heat capacity is formulated in this work for BP via a Sommerfeld expansion. In the concluding part, we draw a microscopic connection between the two seemingly disparate processes of heat removal and absorption by pinning down their origin to the underlying density of states. Finally, a qualitative analysis of a Carnot-like efficiency of the considered thermoelectric engine is performed drawing upon the previous results on thermal current and heat capacity.

Megagauss-level magnetic field production in cm-scale auto-magnetizing helical liners pulsed to 500 kA in 125 ns

NASA Astrophysics Data System (ADS)

Shipley, G. A.; Awe, T. J.; Hutsel, B. T.; Slutz, S. A.; Lamppa, D. C.; Greenly, J. B.; Hutchinson, T. M.

2018-05-01

Auto-magnetizing (AutoMag) liners [Slutz et al., Phys. Plasmas 24, 012704 (2017)] are designed to generate up to 100 T of axial magnetic field in the fuel for Magnetized Liner Inertial Fusion [Slutz et al., Phys. Plasmas 17, 056303 (2010)] without the need for external field coils. AutoMag liners (cylindrical tubes) are composed of discrete metallic helical conduction paths separated by electrically insulating material. Initially, helical current in the AutoMag liner produces internal axial magnetic field during a long (100 to 300 ns) current prepulse with an average current rise rate d I / d t = 5 k A / n s . After the cold fuel is magnetized, a rapidly rising current ( 200 k A / n s ) generates a calculated electric field of 64 M V / m between the helices. Such field is sufficient to force dielectric breakdown of the insulating material after which liner current is reoriented from helical to predominantly axial which ceases the AutoMag axial magnetic field production mechanism and the z-pinch liner implodes. Proof of concept experiments have been executed on the Mykonos linear transformer driver to measure the axial field produced by a variety of AutoMag liners and to evaluate what physical processes drive dielectric breakdown. A range of field strengths have been generated in various cm-scale liners in agreement with magnetic transient simulations including a measured field above 90 T at I = 350 kA. By varying the helical pitch angle, insulator material, and insulator geometry, favorable liner designs have been identified for which breakdown occurs under predictable and reproducible field conditions.

Onset and Dynamics of a Subaqueous Dune Field in a Tideless Erosional Deltaic Shoreface: an Analog for the Initial Development of Sand Ridges

NASA Astrophysics Data System (ADS)

Guerrero, Q.; Guillén, J.; Durán, R.; Urgeles, R.

2016-12-01

A subaqueous dune field located over a retreating deltaic lobe in the Ebro delta (NW Mediterranean) is morphodynamically characterized by analyzing three sets of co-located, multibeam bathymetric data acquired in 2004, 2013 and 2015, measurements of near-bottom currents and suspended sediment concentrations, high-resolution seismic profiles and aerial photographs. The dunes, made of fine sand, extend from 5 to 15 m water depth, have straight crestlines and maximum heights and wavelengths of 2.5 and 350 m, respectively (Fig. 1). Results suggest that the onset of dune field development is closely related to the contemporary evolution of the Ebro delta. A change in the main river channel in the 1940s led to the progressive abandonment of the former river mouth, severe coastal retreatment ( 37 m·y-1) and increased sediment availability. The characteristic NW winds of the region induce near-bottom currents flowing towards the SE which are able to rework and transport these sediments. The dune field developed over the shoreface of the abandoned river mouth and is currently active with mean SE migration rates of 10 m·y-1, most likely when high-energetic currents occur. The morphology of the dune field and crestline obliquity to shoreline orientation agree well with that observed in sand ridges of continental shelves worldwide. Mid-outer shelf sand ridges have been interpreted as sedimentary bodies formed in coastal waters and detached from the coast during sea level rise. The studied dune field could therefore be an example of the initial stages of sand ridges development when large amounts of sand are suddenly available. The field developed when the river mouth switched, favored by a pre-existing seafloor irregularity. Despite the time-scale for the genesis and evolution of shoreface sand ridges has been set in time-scales of hundreds/thousands of years, this study shows that shoreface sand ridges can develop during shorter time-scales (tens of years). Furthermore, it is discussed that, in absence of a rapid sea level rise, these sand ridges probably will vanish as a consequence of sediment scarcity and wave reworking.

Atomic Processes in a Plasma Opening Switch.

NASA Astrophysics Data System (ADS)

Klepper, C. C.; Moschella, J. J.; Hazelton, R. C.; Yadlowsky, E. J.; Maron, Y.

1998-11-01

Detailed measurements of carbon emission have been carried out in a Plasma Opening Switch (POS) with a planar geometry, in order to characterize the plasma conditions and the ionization process in the POS. Emission from various transitions of C^circ to C^3+ has been measured as a function of time from several viewing chords. For these experiments, the POS was operated with a shorted load at 130kA and with a ~700ns conduction time. A single-chord, heterodyne interferometer measured the electron density evolution along a chord coincident with one of the spectroscopic views. The passage of the ionization front across the line of sight is witnessed by both diagnostics. The data are interpreted by analyzing the time-dependent atomic processes. The measured ne rises from 1.5×10^15 to 3×10^15cm-3 as the current crosses the view. An initial electron temperature in the 1.3-2 eV range is obtained from the ratio of the C II 4267 Åand 6578 Ålines. The time dependent line emission of the various charge states shows that Te rises to a few tens of eV at the peak current. The charge state distribution during the pulse will be discussed.

Final project memorandum: sea-level rise modeling handbook: resource guide for resource managers, engineers, and scientists

USGS Publications Warehouse

Doyle, Thomas W.

2015-01-01

Coastal wetlands of the Southeastern United States are undergoing retreat and migration from increasing tidal inundation and saltwater intrusion attributed to climate variability and sea-level rise. Much of the literature describing potential sea-level rise projections and modeling predictions are found in peer-reviewed academic journals or government technical reports largely suited to reading by other Ph.D. scientists who are more familiar or engaged in the climate change debate. Various sea-level rise and coastal wetland models have been developed and applied of different designs and scales of spatial and temporal complexity for predicting habitat and environmental change that have not heretofore been synthesized to aid natural resource managers of their utility and limitations. Training sessions were conducted with Federal land managers with U.S. Fish and Wildlife Service, National Park Service, and NOAA National Estuarine Research Reserves as well as state partners and nongovernmental organizations across the northern Gulf Coast from Florida to Texas to educate and to evaluate user needs and understanding of concepts, data, and modeling tools for projecting sea-level rise and its impact on coastal habitats and wildlife. As a result, this handbook was constructed from these training and feedback sessions with coastal managers and biologists of published decision-support tools and simulation models for sea-level rise and climate change assessments. A simplified tabular context was developed listing the various kinds of decision-support tools and ecological models along with criteria to distinguish the source, scale, and quality of information input and geographic data sets, physical and biological constraints and relationships, datum characteristics of water and land elevation components, utility options for setting sea-level rise and climate change scenarios, and ease or difficulty of storing, displaying, or interpreting model output. The handbook is designed to be a primer to understanding sea-level rise and a practical synthesis of the current state of knowledge and modeling tools as a resource guide for DOl land management needs and facilitating Landscape Conservation Cooperative (LCC) research and conservation initiatives.

Analysis of the Key and Difficult Points in the Engineering Construction Technology of the Steel Structures of a Super High-rise Building

NASA Astrophysics Data System (ADS)

Dou, Lijun; Li, Hengxu

2017-07-01

In recent years, with the rapid development of the economy of China, the traditional building structure has not been able to meet the current people’s demands and the super high-rise building has become a symbol of a city. In the current period, the research on the super high-rise building in the architectural industry of China is late and the technical blanks exist in some construction difficulties in the super high-rise steel structures. Based on the above, a brief analysis and discussion on the difficult construction technology in the steel structures of a super high-rise building and some measures are presented for reference of the relevant personnel in this paper.

Pulse generator using transistors and silicon controlled rectifiers produces high current pulses with fast rise and fall times

NASA Technical Reports Server (NTRS)

Woolfson, M. G.

1966-01-01

Electrical pulse generator uses power transistors and silicon controlled rectifiers for producing a high current pulse having fast rise and fall times. At quiescent conditions, the standby power consumption of the circuit is equal to zero.

Inattentiveness, parental smoking and adolescent smoking initiation.

PubMed

Barman, Satu K; Pulkkinen, Lea; Kaprio, Jaakko; Rose, Richard J

2004-08-01

To examine how adolescents' inattentive behaviour, together with parental smoking patterns, predicts smoking initiation by age 14. DESIGN, SETTINGS: A prospective, longitudinal study: baseline at ages 11-12, follow-up at age 14. A population-based sample of Finnish twins, born 1983-1987, with parents and classroom teachers as additional informants. Two groups were formed, allocating the co-twins of each family into separate groups: the study sample and a replication sample. Twin individuals (n = 4552), aged 11-12 at baseline and 14 (average 14.04 years) at follow-up. At baseline, inattentiveness was assessed with the Multidimensional Peer Nomination Inventory (MPNI, Teacher Form) and parental smoking with individual questionnaires completed by each twins' parents; at the age 14 follow-up, adolescent smoking was assessed with a self-report questionnaire. At age 14, 57% reported never having smoked, 34% had experimented with cigarettes and 9% were current smokers. Inattentiveness and parental smoking additively predicted both experimental and current smoking in adolescence. The effects were independent of each other. The risk related to inattentiveness itself is high, but in combination with the effects of parental smoking, the probability of current smoking can rise as high as 38%, compared with 5% without these two risk factors. For prevention purposes, parental commitment to non-smoking should be emphasized.

Evaluating the Impact of Sea Level Rise and Coastal Flooding on NASA Centers and Facilities by Implementing Terrestrial Laser Scanning Surveys to Improve Coastal Digital Elevation and Inundation Models

NASA Astrophysics Data System (ADS)

Bell, L. J.; Nerem, R. S.; Williams, K.; Meertens, C.; Lestak, L.; Masters, D.

2014-12-01

Sea level is rising in response to climate change. Currently the global mean rate is a little over 3 mm/year, but it is expected to accelerate significantly over this century. This will have a profound impact on coastal populations and infrastructure, including NASA centers and facilities. A detailed study proposed by the University of Colorado's Center for Astrodynamics Research on the impact of sea level rise on several of NASA's most vulnerable facilities was recently funded by NASA. Individual surveys at several high-risk NASA centers were conducted and used as case studies for a broader investigation that needs to be done for coastal infrastructure around the country. The first two years of this study included implementing and conducting a terrestrial laser scanning (TLS) and GPS survey at Kennedy Space Center, Cape Canaveral, Florida, Wallops Flight Facility, Wallops Island, Virginia, Langley Research Center, Hampton, Virginia, and Ames Research Center, Moffett Field, California. We are currently using airborne LiDAR (Light Detection and Ranging) data and TLS (Terrestrial Laser Scanning) data to construct detailed digital elevation models (DEMs) of the facilities that we have assessed. The TLS data acquired at each center provides a very dense point cloud that is being used to improve the detail and accuracy of the digital elevation models currently available. We are also using GPS data we acquired at each center to assess the rate of vertical land movement at the facilities and to tie the DEM to tide gauges and other reference points. With completed, detailed DEMs of the topography and facilities at each center, a series of simple inundation models will then be applied to each area. We will use satellite altimeter data from TOPEX, Jason-1, and Jason-2 to assess the sea level changes observed near these NASA facilities over the last 20 years along with sea level projections from global climate models (GCMs) and semi-empirical projections to make detailed maps of sea level inundation through and up to the years 2050 and 2100 for varying amounts of sea level rise. We will also work with other selected investigators to assess the effects of tidal variations and storm surge when coupled with changes in mean sea level, as storm surge is likely when initial damage due to sea level rise will occur.

Increasing Resilience Through Engagement In Sea Level Rise Community Science Initiatives.

NASA Astrophysics Data System (ADS)

Chilton, L. A.; Rindge, H.

2017-12-01

Science literate and engaged members of the public, including students, are critical to building climate resilient communities. USC Sea Grant facilitates programs that work to build and strengthen these connections. The Urban Tides Community Science Initiative (Urban Tides) and the Youth Exploring Sea Level Rise Science Program (YESS) engage communities across the boundaries of public engagement, K-12 education, and informal education. YESS is an experiential sea level rise education program that combines classroom learning, field investigations and public presentations. Students explore sea level rise using a new curricula, collect their own data on sea level rise, develop communication products, and present their findings to city governments, researchers, and others. Urban Tides engages community members, informal education centers, K-12 students, and local government leaders in a citizen science program photo- documenting extreme high tides, erosion and coastal flooding in Southern California. Images provide critical information to help calibrate scientific models used to identify locations vulnerable to damage from future sea level rise. These tools and information enable community leaders and local governments to set priorities, guidelines, and update policies as they plan strategies that will help the region adapt. The program includes a mobile app for data collection, an open database to view photos, a lesson plan, and community beach walks. Urban Tides has led to an increase in data and data-gathering capacity for regional scientists, an increase in public participation in science, and an increase in ocean and climate literacy among initiative participants. Both of these programs bring informed and diverse voices into the discussion of how to adapt and build climate resilient communities. USC Sea Grant will share impacts and lessons learned from these two unique programs.

Health care quality, access, cost, workforce, and surgical education: the ultimate perfect storm.

PubMed

Schwartz, Marshall Z

2012-01-01

The discussions on health care reform over the past two years have focused on cost containment while trying to maintain quality of care. Focusing on just cost and quality unfortunately does not address other very important factors that impact on our health care delivery system. Availability of a well-trained workforce, maintaining the sophisticated medical/surgical education system, and ultimately access to quality care by the public are critical to maintaining and enhancing our health care delivery system. Unfortunately, all five of these components are under at risk. Thus, we have evolving the ultimate perfect storm affecting our health care delivery system. Although not ideal and given the uniqueness of our population and their expectations, our current delivery system is excellent compared to other countries. However, the cost of our current system is rising at an alarming rate. Currently, health care consumes 17% of our gross domestic product. If our system is not revised this will continue to rise and by 2025 it will consume 48%. The dilemma, given the current state of our overall economy and rising debt, is how to address this major problem. Unfortunately, the Affordable Care Act, which is now law, does not address most of the issues and the cost was initially grossly under estimated. Furthermore, the law does not address the issues of workforce, maintaining our medical education system or ultimately, access. A major revision of our system will be necessary to truly create a system that protects and enhances all five of the components of our health care delivery system. To effectively accomplish this will require addressing those issues that lead to wasteful spending and diversion of our health care dollars to profit instead of care. Improved and efficient delivery systems that reduce complications, reduction of duplication of tertiary and quaternary programs or services within the same markets (i.e. regionalization of care), health insurance reform, and tort reform collectively could save hundreds of billion dollars per year! These changes may not be easy to accomplish politically but will be essential to save what is likely the best health care system in the world. Copyright © 2012. Published by Elsevier Inc.

Immunization Equity.

PubMed

Hinman, Alan R; McKinlay, Mark A

2015-12-01

Health inequities are the unjust differences in health among different social groups. Unfortunately, inequities are the norm, both in terms of health status and access to, and use of, health services. Childhood immunizations reduce the incidence of vaccine-preventable diseases and represent a cost-effective way to foster health equity. This paper reflects a 2015 review of data from surveys conducted in developing countries from 2005 to 2011 that show significant inequities in immunization coverage and discusses several initiatives currently underway (including Gavi, the Vaccine Alliance) that are directed at increasing childhood immunizations or reducing or abolishing overall health inequities. These initiatives have already had a significant impact on disease burden and childhood mortality and give rise to optimism that health disparities may further be reduced and health equity achieved as a result of investments made in immunization. Copyright © 2015 2015 by American Journal of Preventive Medicine and Els. Published by Elsevier Inc. All rights reserved.

Using time lapse cameras to monitor shoreline changes due to sea level rise.

DOT National Transportation Integrated Search

2017-01-01

Shoreline habitats and infrastructure are currently being affected by sea level rise (SLR) and as : global temperatures continue to rise, will continue to get worse for millennia. Governments : and individuals decisions to adapt to SLR could ha...

Rheumatology Informatics System for Effectiveness: A National Informatics-Enabled Registry for Quality Improvement.

PubMed

Yazdany, Jinoos; Bansback, Nick; Clowse, Megan; Collier, Deborah; Law, Karen; Liao, Katherine P; Michaud, Kaleb; Morgan, Esi M; Oates, James C; Orozco, Catalina; Reimold, Andreas; Simard, Julia F; Myslinski, Rachel; Kazi, Salahuddin

2016-12-01

The Rheumatology Informatics System for Effectiveness (RISE) is a national electronic health record (EHR)-enabled registry. RISE passively collects data from EHRs of participating practices, provides advanced quality measurement and data analytic capacities, and fulfills national quality reporting requirements. Here we report the registry's architecture and initial data, and we demonstrate how RISE is being used to improve the quality of care. RISE is a certified Centers for Medicare and Medicaid Services Qualified Clinical Data Registry, allowing collection of data without individual patient informed consent. We analyzed data between October 1, 2014 and September 30, 2015 to characterize initial practices and patients captured in RISE. We also analyzed medication use among rheumatoid arthritis (RA) patients and performance on several quality measures. Across 55 sites, 312 clinicians contributed data to RISE; 72% were in group practice, 21% in solo practice, and 7% were part of a larger health system. Sites contributed data on 239,302 individuals. Among the subset with RA, 34.4% of patients were taking a biologic or targeted synthetic disease-modifying antirheumatic drug (DMARD) at their last encounter, and 66.7% were receiving a nonbiologic DMARD. Examples of quality measures include that 55.2% had a disease activity score recorded, 53.6% a functional status score, and 91.0% were taking a DMARD in the last year. RISE provides critical infrastructure for improving the quality of care in rheumatology and is a unique data source to generate new knowledge. Data validation and mapping are ongoing and RISE is available to the research and clinical communities to advance rheumatology. © 2016, American College of Rheumatology.

Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time

NASA Astrophysics Data System (ADS)

Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

2016-03-01

Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time.

PubMed

Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

2016-03-01

Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

Potassium Currents of Olfactory Bulb Juxtaglomerular Cells: Characterization, Simulation, and Implications for Plateau Potential Firing

PubMed Central

Masurkar, Arjun V.; Chen, Wei R.

2011-01-01

Odor identity is encoded by the activity of olfactory bulb glomeruli, which receive primary sensory input and transfer it to projection neurons. Juxtaglomerular cells (JGCs) may influence glomerular processing via firing of long lasting plateau potentials. Though inward currents have been investigated, little is known regarding potassium current contribution to JGC plateau potentials. We pursued study of these currents, with the overarching goal of creating components for a computational model of JGC plateau potential firing. In conditions minimizing calcium-activated potassium current (IK(Ca)), we used whole cell voltage clamp and in vitro slice preparations to characterize three potassium currents in rat JGCs. The prominent component Ikt1 displayed rapid kinetics (τ10%−90% rise 0.6–2ms, τinactivation 5–10ms) and was blocked by high concentration 4-AP (5mM) and TEA (40mM). It had half maximal activation at −10mV (V½max) and little inactivation at rest. Ikt2, with slower kinetics (τ10%−90% rise 11–15ms, τinactivation 100–300ms), was blocked by low concentration 4-AP (0.5mM) and TEA (5mM). The V½max was 0mV and inactivation was also minimal at rest. Sustained current Ikt3 showed sensitivity to low concentration 4-AP and TEA, and had V½max of +10mV. Further experiments, in conditions of physiologic calcium buffering, suggested that IK(Ca) contributed to Ikt3 with minimal effect on plateau potential evolution. We transformed these characterizations into Hodgkin-Huxley models that robustly mimicked experimental data. Further simulation demonstrated that Ikt1 would be most efficiently activated by plateau potential waveforms, predicting a critical role in shaping JGC firing. These studies demonstrated that JGCs possess a unique potassium current profile, with delayed rectifier (Ikt3), atypical A-current (Ikt1), and D-current (Ikt2) in accordance with known expression patterns in OB glomeruli. Our simulations also provide an initial framework for more integrative models of JGC plateau potential firing. PMID:21704678

Validation and Refinement of the DELFIC Cloud Rise Module

DTIC Science & Technology

1977-01-15

Explosion Energy Fraction in the Cloud, f 13 2.4.2 Temper&ture of Condensed-Phase Matter 13 2.4.3 Altitude 14 2.4.4 Rise V0elociy 14 2.4.5 Mass and Volume 15...2.4.1 Explosion Energy Fraction in the Cloud. f. The original NRDL water-surface burst model used an energy fraction of 33%. For the first DELFIC...of explosion energy) is used to heat soil and air to their respective initial tempera- tures. The soil mans and both initial temperatures are

Shear-induced opening of the coronal magnetic field

NASA Technical Reports Server (NTRS)

Wolfson, Richard

1995-01-01

This work describes the evolution of a model solar corona in response to motions of the footpoints of its magnetic field. The mathematics involved is semianalytic, with the only numerical solution being that of an ordinary differential equation. This approach, while lacking the flexibility and physical details of full MHD simulations, allows for very rapid computation along with complete and rigorous exploration of the model's implications. We find that the model coronal field bulges upward, at first slowly and then more dramatically, in response to footpoint displacements. The energy in the field rises monotonically from that of the initial potential state, and the field configuration and energy appraoch asymptotically that of a fully open field. Concurrently, electric currents develop and concentrate into a current sheet as the limiting case of the open field is approached. Examination of the equations shows rigorously that in the asymptotic limit of the fully open field, the current layer becomes a true ideal MHD singularity.

Review of Article, A Case for Submicrosecond Rise-Time Lightning Current Pulses for Use in Aircraft Induced-Coupling Studies, by D. W. Clifford, E. P. Krider and M. A. Uman

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

Cabayan, H.S.; Zicker, J.D.

The amplitudes of currents due to lightning are considerably larger than NEMP induced currents both in the time and frequency domains. The more important quantity for aperture illumination is the rate of rise of the current. The analysis performed for this in this memorandum is unsatisfactory since the artificial double exponential model was used. Still, the lightning rate of rise is only twice as high as that due to NEMP even when the absolute worst (or presently known) lightning pulse is used. A much better way to do this comparison is to use an actual LEMP data and NEMP frommore » an actual weapon. Furthermore, because of lack of data, no electric field analysis was undertaken.« less

30 CFR 203.54 - How does my relief arrangement for an oil and gas lease operate if prices rise sharply?

Code of Federal Regulations, 2010 CFR

2010-07-01

... gas lease operate if prices rise sharply? 203.54 Section 203.54 Mineral Resources MINERALS MANAGEMENT... arrangement for an oil and gas lease operate if prices rise sharply? In those months when your current reference price rises by at least 25 percent above your base reference price, you must pay the effective...

Integrating wildfire plume rises within atmospheric transport models

NASA Astrophysics Data System (ADS)

Mallia, D. V.; Kochanski, A.; Wu, D.; Urbanski, S. P.; Krueger, S. K.; Lin, J. C.

2016-12-01

Wildfires can generate significant pyro-convection that is responsible for releasing pollutants, greenhouse gases, and trace species into the free troposphere, which are then transported a significant distance downwind from the fire. Oftentimes, atmospheric transport and chemistry models have a difficult time resolving the transport of smoke from these wildfires, primarily due to deficiencies in estimating the plume injection height, which has been highlighted in previous work as the most important aspect of simulating wildfire plume transport. As a result of the uncertainties associated with modeled wildfire plume rise, researchers face difficulties modeling the impacts of wildfire smoke on air quality and constraining fire emissions using inverse modeling techniques. Currently, several plume rise parameterizations exist that are able to determine the injection height of fire emissions; however, the success of these parameterizations has been mixed. With the advent of WRF-SFIRE, the wildfire plume rise and injection height can now be explicitly calculated using a fire spread model (SFIRE) that is dynamically linked with the atmosphere simulated by WRF. However, this model has only been tested on a limited basis due to computational costs. Here, we will test the performance of WRF-SFIRE in addition to several commonly adopted plume parameterizations (Freitas, Sofiev, and Briggs) for the 2013 Patch Springs (Utah) and 2012 Baker Canyon (Washington) fires, for both of which observations of plume rise heights are available. These plume rise techniques will then be incorporated within a Lagrangian atmospheric transport model (STILT) in order to simulate CO and CO2 concentrations during NASA's CARVE Earth Science Airborne Program over Alaska during the summer of 2012. Initial model results showed that STILT model simulations were unable to reproduce enhanced CO concentrations produced by Alaskan fires observed during 2012. Near-surface concentrations were drastically overestimated while free tropospheric concentrations of CO were underestimated, likely a result of STILT injecting the fire emissions strictly into the PBL. We show in this study to what degree coupling the STILT model with an external plume rise model can help mitigate these problems.

West German NATO Policy: The Next Five Years

DTIC Science & Technology

1989-11-01

West German conservatives have been confronted by the rise of the Republican party on the radical right . The causes underlying such political shifts...rise of the radical right Republican party, initially founded in Bavaria by several deputies from the the CDU’s sister party, the Christian Social

Rising Dragon: Infrastructure Development and Chinese Influence in Vietnam

DTIC Science & Technology

2009-06-01

This thesis will contribute to the on-going debate over whether China’s rise as a regional and potential global power will be benign or disruptive...bilateral and regional initiatives. These infrastructure developments create the mechanisms for future exploitation by expanding China’s economic and military

The current situation in education and training of health-care professionals across Africa to optimise the delivery of palliative care for cancer patients

PubMed Central

Rawlinson, FM; Gwyther, L; Kiyange, F; Luyirika, E; Meiring, M; Downing, J

2014-01-01

The need for palliative care education remains vital to contribute to the quality of life of patients, both adults and children, with cancer in Africa. The number of patients with cancer continues to rise, and with them the burden of palliative care needs. Palliative care has been present in Africa for nearly four decades, and a number of services are developing in response to the HIV/AIDS epidemic. However, the needs of cancer patients remain a challenge. Education and training initiatives have developed throughout this time, using a combination of educational methods, including, more recently, e-learning initiatives. The role of international and national organisations in supporting education has been pivotal in developing models of education and training that are robust, sustainable, and affordable. Developing a material for education and professional development needs to continue in close collaboration with that already in production in order to optimise available resources. Seeking ways to evaluate programmes in terms of their impact on patient care remains an important part of programme delivery. This article reviews the current situation. PMID:25624873

Lipid effects on neutrophil calcium signaling induced by opsonized particles: platelet activating factor is only part of the story.

PubMed

Wanten, Geert; Kusters, Anneke; van Emst-de Vries, Sjenet E; Tool, Anton; Roos, Dirk; Naber, Ton; Willems, Peter

2004-08-01

Total parenteral nutrition is frequently used in clinical practice to improve the nutritional status of patients. However, the risk for infectious complications remains a drawback in which immune-modulating effects of the lipid component may play a role. To characterize these lipid effects we investigated neutrophil activation by opsonized yeast particles under influence of lipid emulsions derived from fish oil (VLCT), olive oil (LCT-MUFA), soybean oil (LCT), and a physical mixture of coconut and soybean oil (LCT-MCT). Serum-treated zymosan (STZ) evoked a biphasic increase in cytosolic Ca2+ concentration ([Ca2+]c) with an initial slow rise that turned into a second fast rise until a plateau was reached. LCT-MCT (5 mM) pretreatment markedly increased the rate of [Ca2+]c rise during the initial phase, abolished the second phase and lowered the plateau. These effects of LCT-MCT were mimicked by the protein kinase C (PKC) activating phorbol ester PMA. LCT, LCT-MUFA and VLCT, on the other hand, decreased the rate of [Ca2+]c rise during both phases and lowered the plateau. The platelet-activating factor (PAF) receptor antagonist WEB 2086 inhibited the second phase, demonstrating that PAF acts as an intercellular messenger in STZ-induced Ca2+ mobilization, but did not interfere with the stimulatory effect of LCT-MCT or PMA on the initial rate of [Ca2+]c rise. Structurally different lipids act only in part through PAF to distinctively modulate neutrophil calcium signaling in response to activation by opsonized particles. Copyright 2003 Elsevier Ltd.

Bangladesh to prepare for rise in gas demand

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

Not Available

1992-06-01

Bangladesh is moving to expand its natural gas infrastructure in response to rising domestic demand. This paper reports that Bangladesh natural gas demand is expected to rise to 700-850 MMcfd in the next few years from the current level of about 500 MMcfd, the Prime Minister Khaleda Zia.

How Do River Meanders Change with Sea Level Rise and Fall?

NASA Astrophysics Data System (ADS)

Scamardo, J. E.; Kim, W.

2016-12-01

River meander patterns are controlled by numerous factors, including variations in water discharge, sediment input, and base level. However, the effect of sea level rise and fall on meandering rivers has not been thoroughly quantified. This study examines geomorphic changes to meandering rivers as a result of sea level rise and fall. Twenty experimental runs using coarse-grained walnut shell sediment (D50= 500 microns) in a flume tank (2.4m x 0.6m x 0.1m) tested the optimal initial conditions for creating meandering rivers in a laboratory setting as well as variations in base level rise and fall rates. Geomorphic changes were recorded by camera images every 20 seconds for a duration of 4 hours per experiment. Seventeen experiments tested the effects of changes in initial base levels, water discharge between 200 and 400 mL/min, and sediment to water input ratios between 1:1000 and 1:250 while measuring sinuosity, channel geometry, and the timescale of the channel to reach a stable form. Sinuosity and channel activity increased with increasing water discharge, initial base level, and the sediment to water ratio to a point after which the activity decreased with increasing sediment input. Base-level change experiments used initial conditions of 400 mL/min, a 1:750 sediment to water input ratio, and a 6 cm initial base-level to induce river meanders for the initial 2 hours before base-level change occurred. Three separate experiments investigated the effects of increasing rates of sea level change: 0.07 cm/min, 0.1 cm/min, and 0.2 cm/min. Experimental sea level was decreased constantly from a high-stand of 6 cm to a low-stand of 2 cm back to the high-stand base-level in each experiment. The rates of change in the experiments scale roughly from central to glacial cycles. In all three experiments, sea level fall induced meander cut-off while sea level rise prompted greater rates of meander bend erosion and meander growth. Sinuosity increased by 12%, 13.5%, and 24%, respectively in the three experiments, with most sinuosity changes occurring in the downstream reach of the channel. These experiments could provide insight into long term effects of sea level change on modern meandering fluvial systems as well as provide a key to interpreting past fluvial changes in the stratigraphic record.

Effect of an Additional, Parallel Capacitor on Pulsed Inductive Plasma Accelerator Performance

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.; Sivak, Amy D.; Balla, Joseph V.

2011-01-01

A model of pulsed inductive plasma thrusters consisting of a set of coupled circuit equations and a one-dimensional momentum equation has been used to study the effects of adding a second, parallel capacitor into the system. The equations were nondimensionalized, permitting the recovery of several already-known scaling parameters and leading to the identification of a parameter that is unique to the particular topology studied. The current rise rate through the inductive acceleration coil was used as a proxy measurement of the effectiveness of inductive propellant ionization since higher rise rates produce stronger, potentially better ionizing electric fields at the coil face. Contour plots representing thruster performance (exhaust velocity and efficiency) and current rise rate in the coil were generated numerically as a function of the scaling parameters. The analysis reveals that when the value of the second capacitor is much less than the first capacitor, the performance of the two-capacitor system approaches that of the single-capacitor system. In addition, as the second capacitor is decreased in value the current rise rate can grow to be twice as great as the rise rate attained in the single capacitor case.

Emerging commercial molecular tests for the diagnosis of bloodstream infection.

PubMed

Mwaigwisya, Solomon; Assiri, Rasha Assad M; O'Grady, Justin

2015-05-01

Bloodstream infection (BSI) by microorganisms can lead to sepsis. This condition has a high mortality rate, which rises significantly with delays in initiation of appropriate antimicrobial treatment. Current culture methods for diagnosing BSI have long turnaround times and poor clinical sensitivity. While clinicians wait for culture diagnosis, patients are treated empirically, which can result in inappropriate treatment, undesirable side effects and contribute to drug resistance development. Molecular diagnostics assays that target pathogen DNA can identify pathogens and resistance markers within hours. Early diagnosis improves antibiotic stewardship and is associated with favorable clinical outcomes. Nonetheless, limitations of current molecular diagnostic methods are substantial. This article reviews recent commercially available molecular methods that use pathogen DNA to diagnose BSI, either by testing positive blood cultures or directly testing patient blood. We critically assess these tests and their application in clinical microbiology. A view of future directions in BSI diagnosis is also provided.

[Mental Health Promotion Among the Chronic Disabled Population in the Community].

PubMed

Huang, Hui-Chuan; Wang, Li-Hua; Chang, Hsiu-Ju

2015-08-01

Societal ageing and the rising prevalence of chronic disease are important causes that underlie the growth in the number of disabled individuals. The disease-induced psychological distress experienced by this population not only decreases quality of life but also increases demand for healthcare. The healthcare policy for the disabled population currently focuses on community healthcare. Therefore, developing appropriate programs to promote mental health among the disabled population in community settings is a critical issue. The present paper reviews current mental health promotion initiatives that target the disabled population in the community and addresses mental healthcare issues that are prevalent among the chronically disabled; strategies of mental health promotion that use music therapy, reminiscence therapy, and horticultural therapy; and the roles and responsibilities of community professionals in mental healthcare. We offer these perspectives as a reference to promote mental health and to establish holistic community healthcare for chronically disabled individuals.

Phenomena of oscillations in atmospheric pressure direct current glow discharges

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

Liu, Fu-cheng; Yan, Wen; Wang, De-zhen

2013-12-15

Self-sustained oscillations in a dc glow discharge with a semiconductor layer at atmospheric pressure were investigated by means of a one-dimensional fluid model. It is found that the dc glow discharge initially becomes unstable in the subnormal glow region and gives rise to oscillations of plasma parameters. A variety of oscillations with one or more frequencies have been observed under different conditions. The discharge oscillates between the glow discharge mode and the Townsend discharge mode in the oscillations with large amplitude while operates in the subnormal glow discharge mode all the while in the oscillations with small amplitude. Fourier Transformmore » spectra of oscillations reveal the transition mechanism between different oscillations. The effects of semiconductor conductivity on the oscillation frequency of the dominant mode, gas voltage, as well as the discharge current have also been analyzed.« less

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents

DOE PAGES

Yager-Elorriaga, D. A.; Steiner, A. M.; Patel, S. G.; ...

2015-11-19

In this study, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ~600 kA with ~200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. As amore » result, this technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.« less

Management of obstructive sleep apnea in the indigent population: a deviation of standard of care?

PubMed

Hamblin, John S; Sandulache, Vlad C; Alapat, Philip M; Takashima, Masayoshi

2014-03-01

Comprehensive management of patients with obstructive sleep apnea (OSA) typically is managed best via a multidisciplinary approach, involving otolaryngologists, sleep psychologists/psychiatrists, pulmonologists, neurologists, oral surgeons, and sleep trained dentists. By utilizing these resources, one could fashion a treatment individualized to the patient, giving rise to the holistic phrase of "personalized medicine." Unfortunately, in situations and environments with limited resources, the treatment options in an otolaryngologist's armamentarium are restricted--typically to continuous positive airway pressure (CPAP) versus sleep surgery. However, a recent patient encounter highlighted here shows how a hospital's reimbursement policy effectively dictated a patient's medical management to sleep surgery. This occurred although the current gold standard for the initial treatment of OSA is CPAP. Changing the course of medical/surgical management by selectively restricting funding is a cause of concern, especially when it promotes patients to choose a treatment option that is not considered the current standard of care.

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents

NASA Astrophysics Data System (ADS)

Yager-Elorriaga, D. A.; Steiner, A. M.; Patel, S. G.; Jordan, N. M.; Lau, Y. Y.; Gilgenbach, R. M.

2015-11-01

In this work, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ˜600 kA with ˜200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. This technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.

Obesity and hypertension in Latin America: Current perspectives.

PubMed

Ruilope, L M; Nunes Filho, A C B; Nadruz, W; Rodríguez Rosales, F F; Verdejo-Paris, J

In the countries of Central America, South America and the Caribbean, there has been a dramatic rise in obesity, the metabolic syndrome, hypertension and other cardiovascular risk factors in the last few decades. Epidemiological evidence highlights a consistent correlation between obesity and hypertension, and the presence of obesity predisposes an individual to a greater risk of hypertension although the mechanisms remain unclear. Obesity and hypertension are two key drivers of the cardio-renal disease continuum, and patients with uncontrolled cardiovascular risk in their mid-life will likely have an increased risk of clinical cardiovascular and renal outcomes in old age. This article summarizes the current status for the prevalence and consequences of obesity and hypertension in Latin America, with the aim of initiating a call to action to all stakeholders for greater implementation of primary prevention strategies, particularly in the young. Copyright © 2018 SEH-LELHA. Publicado por Elsevier España, S.L.U. All rights reserved.

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents

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

Yager-Elorriaga, D. A.; Steiner, A. M.; Patel, S. G.

In this study, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ~600 kA with ~200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. As amore » result, this technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.« less

The Rise and Fall of Priming: How Visual Exposure Shapes Cortical Representations of Objects

PubMed Central

Zago, Laure; Fenske, Mark J.; Aminoff, Elissa; Bar, Moshe

2006-01-01

How does the amount of time for which we see an object influence the nature and content of its cortical representation? To address this question, we varied the duration of initial exposure to visual objects and then measured functional magnetic resonance imaging (fMRI) signal and behavioral performance during a subsequent repeated presentation of these objects. We report a novel ‘rise-and-fall’ pattern relating exposure duration and the corresponding magnitude of fMRI cortical signal. Compared with novel objects, repeated objects elicited maximal cortical response reduction when initially presented for 250 ms. Counter-intuitively, initially seeing an object for a longer duration significantly reduced the magnitude of this effect. This ‘rise-and-fall’ pattern was also evident for the corresponding behavioral priming. To account for these findings, we propose that the earlier interval of an exposure to a visual stimulus results in a fine-tuning of the cortical response, while additional exposure promotes selection of a subset of key features for continued representation. These two independent mechanisms complement each other in shaping object representations with experience. PMID:15716471

Malaysia and harm reduction: the challenges and responses.

PubMed

Reid, Gary; Kamarulzaman, Adeeba; Sran, Sangeeta Kaur

2007-03-01

In Malaysia the response to illicit drug use has been largely punitive with the current goal of the Malaysian government being to achieve a drug-free society by 2015. This paper outlines the results of a desk-based situation assessment conducted over a 3-week period in 2004. Additional events, examined in 2005, were also included to describe more recent policy developments and examine how these came about. Despite punitive drug policy there has been a substantial rise in the number of drug users in the country. Over two-thirds of HIV/AIDS cases are among injecting drug users (IDUs) and there has been an exponential rise in the number of cases reported. Further, data suggest high risk drug use practices are widespread. Harm reduction initiatives have only recently been introduced in Malaysia. The successful piloting of substitution therapies, in particular methadone and buprenorphine, is cause for genuine hope for the rapid development of such interventions. In 2005 the government announced it will allow methadone maintenance programmes to operate beyond the pilot phase and needle and syringe exchange programmes will be established to serve the needs of IDUs.

Measured close lightning leader-step electric-field-derivative waveforms.

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

Jordan, Doug M.; Hill, Dustin; Biagi, Christopher J.

2010-12-01

We characterize the measured electric field-derivative (dE/dt) waveforms of lightning stepped-leader steps from three negative lightning flashes at distances of tens to hundreds of meters. Electromagnetic signatures of leader steps at such close distances have rarely been documented in previous literature. Individual leader-step three-dimensional locations are determined by a dE/dt TOA system. The leader-step field derivative is typically a bipolar pulse with a sharp initial half-cycle of the same polarity as that of the return stroke, followed by an opposite polarity overshoot that decays relatively slowly to background level. This overshoot increases in amplitude relative to the initial peak andmore » becomes dominant as range decreases. The initial peak is often preceded by a 'slow front,' similar to the slow front that precedes the fast transition to peak in first return stroke dE/dt and E waveforms. The overall step-field waveform duration is typically less than 1 {micro}s. The mean initial peak of dE/dt, range-normalized to 100 km, is 7.4 V m{sup -1} {micro}s{sup -1} (standard deviation (S.D.), 3.7 V m{sup -1} {micro}s{sup -1}, N = 103), the mean half-peak width is 33.5 ns (S.D., 11.9 ns, N = 69), and the mean 10-to-90% risetime is 43.6 ns (S.D., 24.2 ns, N = 69). From modeling, we determine the properties of the leader step currents which produced two typical measured field derivatives, and we use one of these currents to calculate predicted leader step E and dE/dt as a function of source range and height, the results being in good agreement with our observations. The two modeled current waveforms had maximum rates of current rise-to-peak near 100 kA {micro}s{sup -1}, peak currents in the 5-7 kA range, current half-peak widths of about 300 ns, and charge transfers of {approx}3 mC. As part of the modeling, those currents were propagated upward at 1.5 x 10{sup 8} m s{sup -1}, with their amplitudes decaying exponentially with a decay height constant of 25 m.« less

Destabilisation of an Arctic ice cap triggered by a hydro-thermodynamic feedback to summer-melt

NASA Astrophysics Data System (ADS)

Dunse, T.; Schellenberger, T.; Kääb, A.; Hagen, J. O.; Schuler, T. V.; Reijmer, C. H.

2014-05-01

Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the Polar Regions. Here we present continuous GPS measurements and satellite synthetic aperture radar based velocity maps from the Austfonna ice cap, Svalbard, that demonstrate strong links between surface-melt and multiannual ice-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant ice regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of the ice cap's largest drainage basin, Basin-3. The resulting iceberg discharge of 4.2 ± 1.6 Gt a-1 over the period April 2012 to May 2013 triples the calving loss from the entire ice cap. After accounting for the terminus advance, the related sea-level rise contribution of 7.2 ± 2.6 Gt a-1 matches the recent annual ice-mass loss from the entire Svalbard archipelago. Our study highlights the importance of dynamic glacier wastage and illuminates mechanisms that may trigger a sustained increase in dynamic glacier wastage or the disintegration of ice-sheets in response to climate warming, which is acknowledged but not quantified in global projections of sea-level rise.

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.

A short-pulse mode for the SPHINX LTD Z-pinch driver

NASA Astrophysics Data System (ADS)

D'Almeida, Thierry; Lassalle, Francis; Zucchini, Frederic; Loyen, Arnaud; Morell, Alain; Chuvatin, Alexander

2015-11-01

The SPHINX machine is a 6MA, 1 μs, LTD Z-pinch driver at CEA Gramat (France) and primarily used for studying radiation effects. Different power amplification concepts were examined in order to reduce the current rise time without modifying the generator discharge scheme, including the Dynamic Load Current Multiplier (DLCM) proposed by Chuvatin. A DLCM device, capable of shaping the current pulse without reducing the rise time, was developed at CEA. This device proved valuable for isentropic compression experiments in cylindrical geometry. Recently, we achieved a short pulse operation mode by inserting a vacuum closing switch between the DLCM and the load. The current rise time was reduced to ~300 ns. We explored the use of a reduced-height wire array for the Dynamic Flux Extruder in order to improve the wire array compression rate and increase the efficiency of the current transfer to the load. These developments are presented. Potential benefits of these developments for future Z pinch experiments are discussed.

MODELING THE RISE OF FIBRIL MAGNETIC FIELDS IN FULLY CONVECTIVE STARS

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

Weber, Maria A.; Browning, Matthew K., E-mail: mweber@astro.ex.ac.uk

Many fully convective stars exhibit a wide variety of surface magnetism, including starspots and chromospheric activity. The manner by which bundles of magnetic field traverse portions of the convection zone to emerge at the stellar surface is not especially well understood. In the solar context, some insight into this process has been gleaned by regarding the magnetism as consisting partly of idealized thin flux tubes (TFTs). Here we present the results of a large set of TFT simulations in a rotating spherical domain of convective flows representative of a 0.3 M {sub ⊙} main-sequence star. This is the first studymore » to investigate how individual flux tubes in such a star might rise under the combined influence of buoyancy, convection, and differential rotation. A time-dependent hydrodynamic convective flow field, taken from separate 3D simulations calculated with the anelastic equations, impacts the flux tube as it rises. Convective motions modulate the shape of the initially buoyant flux ring, promoting localized rising loops. Flux tubes in fully convective stars have a tendency to rise nearly parallel to the rotation axis. However, the presence of strong differential rotation allows some initially low-latitude flux tubes of moderate strength to develop rising loops that emerge in the near-equatorial region. Magnetic pumping suppresses the global rise of the flux tube most efficiently in the deeper interior and at lower latitudes. The results of these simulations aim to provide a link between dynamo-generated magnetic fields, fluid motions, and observations of starspots for fully convective stars.« less

Advanced Regional and Decadal Predictions of Coastal Inundation for the U.S. Atlantic and Gulf Coasts (Invited)

NASA Astrophysics Data System (ADS)

Horton, B.; Corbett, D. R.; Donnelly, J. P.; Kemp, A.; Lin, N.; Lindeman, K.; Mann, M. E.; Peltier, W. R.; Rahmstorf, S.

2013-12-01

Future inundation of the U.S. Atlantic and Gulf coasts will depend upon sea-level rise and the intensity and frequency of tropical cyclones, each of which will be affected by climate change. Through ongoing, collaborative research we are employing new interdisciplinary approaches to bring about a step change in the reliability of predictions of such inundation. The rate of sea level rise along the U.S. Atlantic and Gulf coasts increased throughout the 20th century. Whilst there is widespread agreement that it continue to accelerate during the 21st century, great uncertainty surrounds its magnitude and geographic variability. Key uncertainties include the role of continental ice sheets, mountain glaciers, and ocean density changes. Insufficient understanding of these complex physical processes precludes accurate prediction of sea-level rise. New approaches using semi-empirical models that relate instrumental records of climate and sea-level rise have projected up to 2 m of sea-level rise by AD 2100. But the time span of instrumental sea-level records is insufficient to adequately constrain the climate:sea-level relationship. We produced new, high-resolution proxy sea-level reconstructions to provide crucial additional constraints to such semi-empirical models. Our dataset spans the alternation between the 'Medieval Climate Anomaly' and 'Little Ice Age'. Before the models can provide appropriate data for coastal management and planning, they must be complemented with regional estimates of sea-level rise. Therefore, the proxy sea-level data has been collected from four study areas (Connecticut, New Jersey, North Carolina and Florida) to accommodate the required extent of regional variability. In the case of inundation arising from tropical cyclones, the historical and observational records are insufficient for predicting their nature and recurrence, because they are such extreme and rare events. Moreover, future storm surges will be superimposed on background sea-level rise. To overcome these problems, we coupled regional sea-level rise projections with hurricane simulations and storm surge models to map coastal inundation for the current climate and the best and worst case climate scenarios of the IPCC AR4. With agency, NGO, and business partners, we have integrated these findings into coastal policy initiatives, including the first ever adoption of sea level Adaptation Action Areas in a Florida city land use plan.

Cost and coverage: implications of the McCain plan to restructure health insurance.

PubMed

Buchmueller, Thomas; Glied, Sherry A; Royalty, Anne; Swartz, Katherine

2008-01-01

Senator John McCain's (R-AZ) health plan would eliminate the current tax exclusion of employer payments for health coverage, replace the exclusion with a refundable tax credit for those who purchase coverage, and encourage Americans to move to a national market for nongroup insurance. Middle-range estimates suggest that initially this change will have little impact on the number of uninsured people, although within five years this number will likely grow as the value of the tax credit falls relative to rising health care costs. Moving toward a relatively unregulated nongroup market will tend to raise costs, reduce the generosity of benefits, and leave people with fewer consumer protections.

Physical Education, Sociology, and Sociology of Sport: Points of Intersection.

ERIC Educational Resources Information Center

Sage, George H.

1997-01-01

Examines the rise of sociology and physical education (PE), discussing linkages that initially existed and the separation that transpired between them. Also examines connections between social theory and PE before the sociology of sport was formally developed. Details the rise of sociology of sport, highlighting roles of physical educators. (SM)

Current costing models: are they suitable for allocating health resources? The example of fall injury prevention in Australia.

PubMed

Moller, Jerry

2005-01-01

The example of fall injury among older people is used to define and illustrate how current Australian systems for allocation of health resources perform for funding emerging public health issues. While the examples are Australian, the allocation and priority setting methods are common in the health sector in all developed western nations. With an ageing population the number of falls injuries in Australia and the cost of treatment will rise dramatically over the next 20-50 years. Current methods of allocating funds within the health system are not well suited to meeting this coming epidemic. The information requirements for cost-benefit and cost-effectiveness measures cannot be met. Marginal approaches to health funding are likely to continue to fund already well-funded treatment or politically driven prevention processes and to miss the opportunity for new prevention initiatives in areas that do not have a high political profile. Fall injury is one of many emerging areas that struggle to make claims for funding because the critical mass of intervention and evidence of its impact is not available. The beneficiaries of allocation failure may be those who treat the disease burden that could have been easily prevented. Changes to allocation mechanisms, data systems and new initiative funding practices are required to ensure that preventative strategies are able to compete on an equal footing with treatment approaches for mainstream health funding.

Nonlinear energy transfer and current sheet development in localized Alfvén wavepacket collisions in the strong turbulence limit

NASA Astrophysics Data System (ADS)

Verniero, J. L.; Howes, G. G.; Klein, K. G.

2018-02-01

In space and astrophysical plasmas, turbulence is responsible for transferring energy from large scales driven by violent events or instabilities, to smaller scales where turbulent energy is ultimately converted into plasma heat by dissipative mechanisms. The nonlinear interaction between counterpropagating Alfvén waves, denoted Alfvén wave collisions, drives this turbulent energy cascade, as recognized by early work with incompressible magnetohydrodynamic (MHD) equations. Recent work employing analytical calculations and nonlinear gyrokinetic simulations of Alfvén wave collisions in an idealized periodic initial state have demonstrated the key properties that strong Alfvén wave collisions mediate effectively the transfer of energy to smaller perpendicular scales and self-consistently generate current sheets. For the more realistic case of the collision between two initially separated Alfvén wavepackets, we use a nonlinear gyrokinetic simulation to show here that these key properties persist: strong Alfvén wavepacket collisions indeed facilitate the perpendicular cascade of energy and give rise to current sheets. Furthermore, the evolution shows that nonlinear interactions occur only while the wavepackets overlap, followed by a clean separation of the wavepackets with straight uniform magnetic fields and the cessation of nonlinear evolution in between collisions, even in the gyrokinetic simulation presented here which resolves dispersive and kinetic effects beyond the reach of the MHD theory.

Taking Her Breath Away: The Rise of COPD in Women

MedlinePlus

... policy . Skip to main content ABOUT US OUR INITIATIVES LUNG HEALTH & DISEASES SUPPORT & COMMUNITY STOP SMOKING GET ... Supporters Careers Contact Us Corporate Ethics Reporting OUR INITIATIVES LUNG FORCE Saved By The Scan Research Healthy ...

75 FR 1803 - Lower Florida Keys Refuges, Monroe County, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-13

... fully assessed and the effect of climate change (e.g., sea level rise) is not known. We would protect... (e.g., hurricanes, wildfire) and global climate change, particularly sea level rise. Current ongoing... evaluate the potential impacts of sea level rise on the ecology of wading birds. Since a primary purpose of...

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...

Leasing instruments of high-rise construction financing

NASA Astrophysics Data System (ADS)

Aleksandrova, Olga; Ivleva, Elena; Sukhacheva, Viktoria; Rumyantseva, Anna

2018-03-01

The leasing sector of the business economics is expanding. Leasing instruments for high-rise construction financing allow to determine the best business behaviour in the leasing economy sector, not only in the sphere of transactions with equipment and vehicles. Investments in high-rise construction have a multiplicative effect. It initiates an active search and leasing instruments use in the economic behaviour of construction organizations. The study of the high-rise construction sector in the structure of the leasing market participants significantly expands the leasing system framework. The scheme of internal and external leasing process factors influence on the result formation in the leasing sector of economy is offered.

Implementation of National Space Policy on US Air Force End of Life Operations and Orbital Debris Mitigation

DTIC Science & Technology

2012-06-01

procedures have been driven by the rising significance of the orbital debris problem in Low Earth Orbit (LEO). Therefore current EOL plans are...does not display a currently valid OMB control number. 1. REPORT DATE JUN 2012 2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4...by the rising significance of the orbital debris problem in Low Earth Orbit (LEO). Therefore current EOL plans are written largely with the aim of

Direct and indirect controls on organic matter decomposition in four coastal wetland communities along a landscape salinity gradient

USGS Publications Warehouse

Stagg, Camille L.; Baustian, Melissa M.; Perry, Carey L.; Carruthers, Tim J.B.; Hall, Courtney T.

2018-01-01

Coastal wetlands store more carbon than most ecosystems globally. As sea level rises, changes in flooding and salinity will potentially impact ecological functions, such as organic matter decomposition, that influence carbon storage. However, little is known about the mechanisms that control organic matter loss in coastal wetlands at the landscape scale. As sea level rises, how will the shift from fresh to salt-tolerant plant communities impact organic matter decomposition? Do long-term, plant-mediated, effects of sea-level rise differ from direct effects of elevated salinity and flooding?We identified internal and external factors that regulated indirect and direct pathways of sea-level rise impacts, respectively, along a landscape-scale salinity gradient that incorporated changes in wetland type (fresh, oligohaline, mesohaline and polyhaline marshes). We found that indirect and direct impacts of sea-level rise had opposing effects on organic matter decomposition.Salinity had an indirect effect on litter decomposition that was mediated through litter quality. Despite significant variation in environmental conditions along the landscape gradient, the best predictors of above- and below-ground litter decomposition were internal drivers, initial litter nitrogen content and initial litter lignin content respectively. Litter decay constants were greatest in the oligohaline marsh and declined with increasing salinity, and the fraction of litter remaining (asymptote) was greatest in the mesohaline marsh. In contrast, direct effects of salinity and flooding were positive. External drivers, salinity and flooding, stimulated cellulytic activity, which was highest in the polyhaline marsh.Synthesis. Our results indicate that as sea level rises, initial direct effects of salinity will stimulate decay of labile carbon, but over time as plant communities shift from fresh to polyhaline marsh, litter decay will decline, yielding greater potential for long-term carbon storage. These findings highlight the importance of quantifying carbon loss at multiple temporal scales, not only in coastal wetlands but also in other ecosystems where plant-mediated responses to climate change will have significant impacts on carbon cycling.

Prevention of Over-Pressurization During Combustion in a Sealed Chamber

NASA Technical Reports Server (NTRS)

Gokoglu, Suleyman A.; Niehaus, Justin E.; Olson, Sandra L.; Dietrich, Daniel L.; Ruff, Gary A.; Johnston, Michael C.

2012-01-01

The combustion of flammable material in a sealed chamber invariably leads to an initial pressure rise in the volume. The pressure rise is due to the increase in the total number of gaseous moles (condensed fuel plus chamber oxygen combining to form gaseous carbon dioxide and water vapor) and, most importantly, the temperature rise of the gas in the chamber. Though the rise in temperature and pressure would reduce with time after flame extinguishment due to the absorption of heat by the walls and contents of the sealed spacecraft, the initial pressure rise from a fire, if large enough, could lead to a vehicle over-pressure and the release of gas through the pressure relief valve. This paper presents a simple lumped-parameter model of the pressure rise in a sealed chamber resulting from the heat release during combustion. The transient model considers the increase in gaseous moles due to combustion, and heat transfer to the chamber walls by convection and radiation and to the fuel-sample holder by conduction, as a function of the burning rate of the material. The results of the model are compared to the pressure rise in an experimental chamber during flame spread tests as well as to the pressure falloff after flame extinguishment. The experiments involve flame spread over thin solid fuel samples. Estimates of the heat release rate profiles for input to the model come from the assumed stoichiometric burning of the fuel along with the observed flame spread behavior. The sensitivity of the model to predict maximum chamber pressure is determined with respect to the uncertainties in input parameters. Model predictions are also presented for the pressure profile anticipated in the Fire Safety-1 experiment, a material flammability and fire safety experiment proposed for the European Space Agency (ESA) Automated Transfer Vehicle (ATV). Computations are done for a range of scenarios including various initial pressures and sample sizes. Based on these results, various mitigation approaches are suggested to prevent vehicle over-pressurization and help guide the definition of the space experiment.

When Might Barrier Island Chains 'Collapse'? An Initial Model Investigation

NASA Astrophysics Data System (ADS)

Slott, J. M.; Murray, A. B.

2007-12-01

There has been recent speculation that, in response to the accelerated sea-level rise and intensified storms expected over the coming century, barrier island chains such as those found on the US Atlantic and Gulf coastlines, could develop large (10-kilometer-scale) gaps in their most narrow stretches, or might disappear completely (Riggs, S. R., 2001). Such a collapse along the North Carolina Outer Banks barrier island chain, for example, would leave the mainland vulnerable to direct hits from Western Atlantic storm systems, and also would dramatically alter the estuarine system it encloses with potentially devastating effects to marine life. Concern for the future of the Outer Banks is also motivated by the decimation of the Chandeleur Islands in 2005 from Hurricane Katrina. We will present a series of initial numerical modeling experiments addressing how barrier island morphodynamics respond to the sudden creation of kilometer-scale gaps. Large-scale barrier island evolution is influenced by sea-level rise and barrier island overwash, alongshore sediment transport, tidal currents, and the availability of mobile sediment. Barrier islands transgress towards the mainland in response to sea-level rise through overwash: ocean-facing shorelines provide sediment that is transported onto the island to maintain its subaerial height and behind the island to maintain its width, while gradients in alongshore sediment transport typically dictate the large-scale shape of a coastline over long time frames (decades to millenia). Tidal currents also tend to scour inlet channels; the relative strength of this effect depends in part upon the width of the inlet channel. Our exploratory model includes both a one-line alongshore transport component and a cross-shore overwash component, as well as representations of underlying geology (weathering rates and material compositions). In our modeling experiments, we test the effects of perforating a 30 km barrier island chain with variable-sized gaps, ranging between 2.5-10 km. In preliminary model experiments, where we do not limit the availability of mobile sediment nor include tidal inlet dynamics, large gaps tend to close under all of the erosion rate scenarios and gap sizes. The ends of barrier islands extend to fill in the gaps and recurve landward. The rate of closure of gaps is unaffected by sea-level rise rates even under the most extreme cases; alongshore sediment fluxes exceed those associated with sea-level rise as highly curved isolated islands migrate rapidly landward before coalescing into an island chain again at a new location. In a natural setting, the overwash and spit-growth that maintain sub-aerial islands and tend to knit them back together (respectively) could be inhibited by a lack of mobile sediment. The shoreface of the Outer Banks, for example, consists of sometimes patchy Holocene sands perched atop a semi-lithified, sometimes more muddy Pleistocene substrate. Weathering of the Pleistocene substrate over long timescales generates mobile sediment consisting of both sands and muds. The fine-grained material, however, is typically lost to the nearshore system. The shoreface may not be able to weather fast enough to keep up with rapidly migrating islands. This effect, combined with that of substrate composition, will tend to limit the rate that sediment can be liberated, and, in turn, could prevent island-chain recovery. We conduct a series of model experiments to determine the combinations of geological parameters (weathering rates, composition) and forcing parameters (rate of sea-level rise, frequency of storms) that prevent barrier-island-chain recovery.

Model development and experimental validation for analyzing initial transients of irradiation of tissues during thermal therapy using short pulse lasers.

PubMed

Ganguly, Mohit; Miller, Stephanie; Mitra, Kunal

2015-11-01

Short pulse lasers with pulse durations in the range of nanoseconds and shorter are effective in the targeted delivery of heat energy for precise tissue heating and ablation. This photothermal therapy is useful where the removal of cancerous tissue sections is required. The objective of this paper is to use finite element modeling to demonstrate the differences in the thermal response of skin tissue to short-pulse and continuous wave laser irradiation in the initial stages of the irradiation. Models have been developed to validate the temperature distribution and heat affected zone during laser irradiation of excised rat skin samples and live anesthetized mouse tissue. Excised rat skin samples and live anesthetized mice were subjected to Nd:YAG pulsed laser (1,064 nm, 500 ns) irradiation of varying powers. A thermal camera was used to measure the rise in surface temperature as a result of the laser irradiation. Histological analyses of the heat affected zone created in the tissue samples due to the temperature rise were performed. The thermal interaction of the laser with the tissue was quantified by measuring the thermal dose delivered by the laser. Finite element geometries of three-dimensional tissue sections for continuum and vascular models were developed using COMSOL Multiphysics. Blood flow was incorporated into the vascular model to mimic the presence of discrete blood vessels and contrasted with the continuum model without blood perfusion. The temperature rises predicted by the continuum and the vascular models agreed with the temperature rises observed at the surface of the excised rat tissue samples and live anesthetized mice due to laser irradiation respectively. The vascular model developed was able to predict the cooling produced by the blood vessels in the region where the vessels were present. The temperature rise in the continuum model due to pulsed laser irradiation was higher than that due to continuous wave (CW) laser irradiation in the initial stages of the irradiation. The temperature rise due to pulsed and CW laser irradiation converged as the time of irradiation increased. A similar trend was observed when comparing the thermal dose for pulsed and CW laser irradiation in the vascular model. Finite element models (continuum and vascular) were developed that can be used to predict temperature rise and quantify the thermal dose resulting from laser irradiation of excised rat skin samples and live anesthetized mouse tissue. The vascular model incorporating blood perfusion effects predicted temperature rise better in the live animal tissue. The models developed demonstrated that pulsed lasers caused greater temperature rise and delivered a greater thermal dose than CW lasers of equal average power, especially during the initial transients of irradiation. This analysis will be beneficial for thermal therapy applications where maximum delivery of thermal dose over a short period of time is important. © 2015 Wiley Periodicals, Inc.

Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

NASA Astrophysics Data System (ADS)

Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay

2017-05-01

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections at the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.

Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

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

Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections atmore » the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.« less

On the design of high-rise buildings with a specified level of reliability

NASA Astrophysics Data System (ADS)

Dolganov, Andrey; Kagan, Pavel

2018-03-01

High-rise buildings have a specificity, which significantly distinguishes them from traditional buildings of high-rise and multi-storey buildings. Steel structures in high-rise buildings are advisable to be used in earthquake-proof regions, since steel, due to its plasticity, provides damping of the kinetic energy of seismic impacts. These aspects should be taken into account when choosing a structural scheme of a high-rise building and designing load-bearing structures. Currently, modern regulatory documents do not quantify the reliability of structures. Although the problem of assigning an optimal level of reliability has existed for a long time. The article shows the possibility of designing metal structures of high-rise buildings with specified reliability. Currently, modern regulatory documents do not quantify the reliability of high-rise buildings. Although the problem of assigning an optimal level of reliability has existed for a long time. It is proposed to establish the value of reliability 0.99865 (3σ) for constructions of buildings and structures of a normal level of responsibility in calculations for the first group of limiting states. For increased (construction of high-rise buildings) and reduced levels of responsibility for the provision of load-bearing capacity, it is proposed to assign respectively 0.99997 (4σ) and 0.97725 (2σ). The coefficients of the use of the cross section of a metal beam for different levels of security are given.

States' Budgets Reflect Rising Tax Collections

ERIC Educational Resources Information Center

Hoff, David J.

2005-01-01

Many state budgets are reaping the benefits of tax revenues that are rising faster than at any time since the economic slowdown ended. Overall tax collections by states rose by 11.7 percent in the first quarter of 2005, giving the legislatures extra cash to shore up school aid, increase teacher pay, and finance new initiatives such as full-day…

Applications of network analysis for adaptive management of artificial drainage systems in landscapes vulnerable to sea level rise

NASA Astrophysics Data System (ADS)

Poulter, Benjamin; Goodall, Jonathan L.; Halpin, Patrick N.

2008-08-01

SummaryThe vulnerability of coastal landscapes to sea level rise is compounded by the existence of extensive artificial drainage networks initially built to lower water tables for agriculture, forestry, and human settlements. These drainage networks are found in landscapes with little topographic relief where channel flow is characterized by bi-directional movement across multiple time-scales and related to precipitation, wind, and tidal patterns. The current configuration of many artificial drainage networks exacerbates impacts associated with sea level rise such as salt-intrusion and increased flooding. This suggests that in the short-term, drainage networks might be managed to mitigate sea level rise related impacts. The challenge, however, is that hydrologic processes in regions where channel flow direction is weakly related to slope and topography require extensive parameterization for numerical models which is limited where network size is on the order of a hundred or more kilometers in total length. Here we present an application of graph theoretic algorithms to efficiently investigate network properties relevant to the management of a large artificial drainage system in coastal North Carolina, USA. We created a digital network model representing the observation network topology and four types of drainage features (canal, collector and field ditches, and streams). We applied betweenness-centrality concepts (using Dijkstra's shortest path algorithm) to determine major hydrologic flowpaths based off of hydraulic resistance. Following this, we identified sub-networks that could be managed independently using a community structure and modularity approach. Lastly, a betweenness-centrality algorithm was applied to identify major shoreline entry points to the network that disproportionately control water movement in and out of the network. We demonstrate that graph theory can be applied to solving management and monitoring problems associated with sea level rise for poorly understood drainage networks in advance of numerical methods.

Glacier-surge mechanisms promoted by a hydro-thermodynamic feedback to summer melt

NASA Astrophysics Data System (ADS)

Dunse, T.; Schellenberger, T.; Hagen, J. O.; Kääb, A.; Schuler, T. V.; Reijmer, C. H.

2015-02-01

Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the polar regions. Here we present continuous GPS measurements and satellite synthetic-aperture-radar-based velocity maps from Basin-3, the largest drainage basin of the Austfonna ice cap, Svalbard. Our observations demonstrate strong links between surface-melt and multiannual ice-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant ice regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of Basin-3. The resulting iceberg discharge of 4.2±1.6 Gt a-1 over the period April 2012 to May 2013 triples the calving loss from the entire ice cap. With the seawater displacement by the terminus advance accounted for, the related sea-level rise contribution amounts to 7.2±2.6 Gt a-1. This rate matches the annual ice-mass loss from the entire Svalbard archipelago over the period 2003-2008, highlighting the importance of dynamic mass loss for glacier mass balance and sea-level rise. The active role of surface melt, i.e. external forcing, contrasts with previous views of glacier surges as purely internal dynamic instabilities. Given sustained climatic warming and rising significance of surface melt, we propose a potential impact of the hydro-thermodynamic feedback on the future stability of ice-sheet regions, namely at the presence of a cold-based marginal ice plug that restricts fast drainage of inland ice. The possibility of large-scale dynamic instabilities such as the partial disintegration of ice sheets is acknowledged but not quantified in global projections of sea-level rise.

Modeling vegetation community responses to sea-level rise on Barrier Island systems: A case study on the Cape Canaveral Barrier Island complex, Florida, USA

PubMed Central

Foster, Tammy E.; Stolen, Eric D.; Hall, Carlton R.; Schaub, Ronald; Duncan, Brean W.; Hunt, Danny K.; Drese, John H.

2017-01-01

Society needs information about how vegetation communities in coastal regions will be impacted by hydrologic changes associated with climate change, particularly sea level rise. Due to anthropogenic influences which have significantly decreased natural coastal vegetation communities, it is important for us to understand how remaining natural communities will respond to sea level rise. The Cape Canaveral Barrier Island complex (CCBIC) on the east central coast of Florida is within one of the most biologically diverse estuarine systems in North America and has the largest number of threatened and endangered species on federal property in the contiguous United States. The high level of biodiversity is susceptible to sea level rise. Our objective was to model how vegetation communities along a gradient ranging from hydric to upland xeric on CCBIC will respond to three sea level rise scenarios (0.2 m, 0.4 m, and 1.2 m). We used a probabilistic model of the current relationship between elevation and vegetation community to determine the impact sea level rise would have on these communities. Our model correctly predicted the current proportions of vegetation communities on CCBIC based on elevation. Under all sea level rise scenarios the model predicted decreases in mesic and xeric communities, with the greatest losses occurring in the most xeric communities. Increases in total area of salt marsh were predicted with a 0.2 and 0.4 m rise in sea level. With a 1.2 m rise in sea level approximately half of CCBIC’s land area was predicted to transition to open water. On the remaining land, the proportions of most of the vegetation communities were predicted to remain similar to that of current proportions, but there was a decrease in proportion of the most xeric community (oak scrub) and an increase in the most hydric community (salt marsh). Our approach provides a first approximation of the impacts of sea level rise on terrestrial vegetation communities, including important xeric upland communities, as a foundation for management decisions and future modeling. PMID:28796807

Many atolls may be uninhabitable within decades due to climate change

USGS Publications Warehouse

Storlazzi, Curt; Elias, Edwin P.L.; Berkowitz, Paul

2015-01-01

Observations show global sea level is rising due to climate change, with the highest rates in the tropical Pacific Ocean where many of the world’s low-lying atolls are located. Sea-level rise is particularly critical for low-lying carbonate reef-lined atoll islands; these islands have limited land and water available for human habitation, water and food sources, and ecosystems that are vulnerable to inundation from sea-level rise. Here we demonstrate that sea-level rise will result in larger waves and higher wave-driven water levels along atoll islands’ shorelines than at present. Numerical model results reveal waves will synergistically interact with sea-level rise, causing twice as much land forecast to be flooded for a given value of sea-level rise than currently predicted by current models that do not take wave-driven water levels into account. Atolls with islands close to the shallow reef crest are more likely to be subjected to greater wave-induced run-up and flooding due to sea-level rise than those with deeper reef crests farther from the islands’ shorelines. It appears that many atoll islands will be flooded annually, salinizing the limited freshwater resources and thus likely forcing inhabitants to abandon their islands in decades, not centuries, as previously thought.

Predicting the persistence of coastal wetlands to global change stressors

USGS Publications Warehouse

Guntenspergen, G.; McKee, K.; Cahoon, D.; Grace, J.; Megonigal, P.

2006-01-01

Despite progress toward understanding the response of coastal wetlands to increases in relative sea-level rise and an improved understanding of the effect of elevated CO2 on plant species allocation patterns, we are limited in our ability to predict the response of coastal wetlands to the effects associated with global change. Static simulations of the response of coastal wetlands to sea-level rise using LIDAR and GIS lack the biological and physical feedback mechanisms present in such systems. Evidence from current research suggests that biotic processes are likely to have a major influence on marsh vulnerability to future accelerated rates of sea-level rise and the influence of biotic processes likely varies depending on hydrogeomorphic setting and external stressors. We have initiated a new research approach using a series of controlled mesocosm and field experiments, landscape scale studies, a comparative network of brackish coastal wetland monitoring sites and a suite of predictive models that address critical questions regarding the vulnerability of coastal brackish wetland systems to global change. Specifically, this research project evaluates the interaction of sea level rise and elevated CO2 concentrations with flooding, nutrient enrichment and disturbance effects. The study is organized in a hierarchical structure that links mesocosm, field, landscape and biogeographic levels so as to provide important new information that recognizes that coastal wetland systems respond to multiple interacting drivers and feedback effects controlling wetland surface elevation, habitat stability and ecosystem function. We also present a new statistical modelling technique (Structural Equation Modelling) that synthesizes and integrates our environmental and biotic measures in a predictive framework that forecasts ecosystem change and informs managers to consider adaptive shifts in strategies for the sustainable management of coastal wetlands.

Tidal dynamics in a changing lagoon: Flooding or not flooding the marginal regions

NASA Astrophysics Data System (ADS)

Lopes, Carina L.; Dias, João M.

2015-12-01

Coastal lagoons are low-lying systems under permanent changes motivated by natural and anthropogenic factors. Ria de Aveiro is such an example with its margins currently threatened by the advance of the lagoonal waters recorded during the last decades. This work aims to study the tidal modifications found between 1987 and 2012 in this lagoon, motivated by the main channels deepening which induce higher inland tidal levels. Additionally it aims to study the impact that protective walls designed to protect the margins against flooding may have in those modifications under sea level rise predictions. The hydrodynamic model ELCIRC previously calibrated for Ria de Aveiro was used and tidal asymmetry, tidal ellipses and residual currents were analyzed for different scenarios, considering the mean sea level rise predicted for 2100 and the implementation of probable flood protection walls. Results evidenced that lagoon dominance remained unchanged between 1987 and 2012, but distortion decreased/increased in the deeper/shallower channels. The same trend was found under mean sea level rise conditions. Tidal currents increased over this period inducing an amplification of the water properties exchange within the lagoon, which will be stronger under mean sea level rise conditions. The deviations between scenarios with or without flood protection walls can achieve 60% for the tidal distortion and residual currents and 20% for the tidal currents, highlighting that tidal properties are extremely sensitive to the lagoon geometry. In summary, the development of numerical modelling applications dedicated to study the influence of mean sea level rise on coastal low-lying systems subjected to human influence should include structural measures designed for flood defence in order to accurately predict changes in the local tidal properties.

Liquid Nitrogen as Fast High Voltage Switching Medium

NASA Astrophysics Data System (ADS)

Dickens, J.; Neuber, A.; Haustein, M.; Krile, J.; Krompholz, H.

2002-12-01

Compact pulsed power systems require new switching technologies. For high voltages, liquid nitrogen seems to be a suitable switching medium, with high hold-off voltage, low dielectric constant, and no need for pressurized systems as in high pressure gas switches. The discharge behavior in liquid nitrogen, such as breakdown voltages, formative times, current rise as function of voltage, recovery, etc. are virtually unknown, however. The phenomenology of breakdown in liquid nitrogen is investigated with high speed (temporal resolution < 1 ns) electrical and optical diagnostics, in a coaxial system with 50-Ohm impedance. Discharge current and voltage are determined with transmission line type current sensors and capacitive voltage dividers. The discharge luminosity is measured with photomultiplier tubes. Preliminary results of self-breakdown investigations (gap 1 mm, breakdown voltage 44 kV, non-boiling supercooled nitrogen) show a fast (2 ns) transition from an unknown current level to several mA, a long-duration (100 ns) phase with constant current superimposed by ns-spikes, and a final fast transition to the impedance limited current during several nanoseconds. The optical measurements will be expanded toward spectroscopy and high speed photography with the aim of clarifying the overall breakdown mechanisms, including electronic initiation, bubble formation, bubble dynamics, and their role in breakdown, for different electrode geometries (different macroscopic field enhancements).

Abnormal human chorionic gonadotropin (hCG) trends after transfer of multiple embryos resulting in viable singleton pregnancies.

PubMed

Brady, Paula C; Farland, Leslie V; Missmer, Stacey A; Racowsky, Catherine; Fox, Janis H

2018-03-01

The purpose of this study is to investigate whether abnormal hCG trends occur at a higher incidence among women conceiving singleton pregnancies following transfer of multiple (two or more) embryos (MET), as compared to those having a single embryo transfer (SET). Retrospective cohort study was performed of women who conceived singleton pregnancies following fresh or frozen autologous IVF/ICSI cycles with day 3 or day 5 embryo transfers between 2007 and 2014 at a single academic medical center. Cycles resulting in one gestational sac on ultrasound followed by singleton live birth beyond 24 weeks of gestation were included. Logistic regression models adjusted a priori for patient age at oocyte retrieval and day of embryo transfer were used to estimate the Odds Ratio of having an abnormal hCG rise (defined as a rise or < 66% in 2 days) following SET as compared to MET. Among patients receiving two or more embryos, 6.1% (n = 84) had abnormal hCG rises between the first and second measurements, compared to 2.7% (n = 17) of patients undergoing SET (OR 2.16, 95% CI 1.26-3.71). Among patients with initially abnormal hCG rises who had a third level checked (89%), three-quarters had normal hCG rises between the second and third measurements. Patients who deliver singletons following MET were more likely to have suboptimal initial hCG rises, potentially due to transient implantation of other non-viable embryo(s). While useful for counseling, these findings should not change standard management of abnormal hCG rises following IVF. The third hCG measurements may clarify pregnancy prognosis.

Bifurcation of the Kuroshio Extension at the Shatsky Rise

NASA Astrophysics Data System (ADS)

Hurlburt, Harley E.; Metzger, E. Joseph

1998-04-01

A 1/16° six-layer Pacific Ocean model north of 20°S is used to investigate the bifurcation of the Kuroshio Extension at the main Shatsky Rise and the pathway of the northern branch from the bifurcation to the subarctic front. Upper ocean-topographic coupling via a mixed barotropic-baroclinic instability is essential to this bifurcation and to the formation and mean pathway of the northern branch as are several aspects of the Shatsky Rise complex of topography and the latitude of the Kuroshio Extension in relation to the topography. The flow instabilities transfer energy to the abyssal layer where it is constrained by geostrophic contours of the bottom topography. The topographically constrained abyssal currents in turn steer upper ocean currents, which do not directly impinge on the bottom topography. This includes steering of mean pathways. Obtaining sufficient coupling requires very fine resolution of mesoscale variability and sufficient eastward penetration of the Kuroshio as an unstable inertial jet. Resolution of 1/8° for each variable was not sufficient in this case. The latitudinal extent of the main Shatsky Rise (31°N-36°N) and the shape of the downward slope on the north side are crucial to the bifurcation at the main Shatsky Rise, with both branches passing north of the peak. The well-defined, relatively steep and straight eastern edge of the Shatsky Rise topographic complex (30°N-42°N) and the southwestward abyssal flow along it play a critical role in forming the rest of the Kuroshio northern branch which flows in the opposite direction. A deep pass between the main Shatsky Rise and the rest of the ridge to the northeast helps to link the northern fork of the bifurcation at the main rise to the rest of the northern branch. Two 1/16° "identical twin" interannual simulations forced by daily winds 1981-1995 show that the variability in this region is mostly nondeterministic on all timescales that could be examined (up to 7 years in these 15-year simulations). A comparison of climatologically forced and interannual simulations over the region 150°E-180°E, 29°N-47°N showed greatly enhanced abyssal and upper ocean eddy kinetic energy and much stronger mean abyssal currents east of the Emperor Seamount Chain (about 170°E) in the interannual simulations but little difference west of 170°E. This greatly enhanced the upper ocean-topographic coupling in the interannual simulations east of 170°E. This coupling affected the latitudinal positioning of the eastward branches of the Kuroshio Extension and tended to reduce latitudinal movement compared to the climatologically forced simulation, including a particularly noticeable impact from the Hess Rise. Especially in the interannual simulations, effects of almost all topographic features in the region could be seen in the mean upper ocean currents (more so than in instantaneous currents), including meanders and bifurcations of major and minor currents, closed circulations, and impacts from depressions and rises of large and small amplitudes.

Parameters of triggered-lightning flashes in Florida and Alabama

NASA Astrophysics Data System (ADS)

Fisher, R. J.; Schnetzer, G. H.; Thottappillil, R.; Rakov, V. A.; Uman, M. A.; Goldberg, J. D.

1993-12-01

Channel base currents from triggered lightning were measured at the NASA Kennedy Space Center, Florida, during summer 1990 and at Fort McClellan, Alabama, during summer 1991. Additionally, 16-mm cinematic records with 3- or 5-ms resolution were obtained for all flashes, and streak camera records were obtained for three of the Florida flashes. The 17 flashes analyzed here contained 69 strokes, all lowering negative charge from cloud to ground. Statistics on interstroke interval, no-current interstroke interval, total stroke duration, total stroke charge, total stroke action integral (∫ i2dt), return stroke current wave front characteristics, time to half peak value, and return stroke peak current are presented. Return stroke current pulses, characterized by rise times of the order of a few microseconds or less and peak values in the range of 4 to 38 kA, were found not to occur until after any preceding current at the bottom of the lightning channel fell below the noise level of less than 2 A. Current pulses associated with M components, characterized by slower rise times (typically tens to hundreds of microseconds) and peak values generally smaller than those of the return stroke pulses, occurred during established channel current flow of some tens to some hundreds of amperes. A relatively strong positive correlation was found between return stroke current average rate of rise and current peak. There was essentially no correlation between return stroke current peak and 10-90% rise time or between return stroke peak and the width of the current waveform at half of its peak value. Parameters of the lightning flashes triggered in Florida and Alabama are similar to each other but are different from those of triggered lightning recorded in New Mexico during the 1981 Thunderstorm Research International Program. Continuing currents that follow return stroke current peaks and last for more than 10 ms exhibit a variety of wave shapes that we have subdivided into four categories. All such continuing currents appear to start with a current pulse presumably associated with an M component. A brief summary of lightning parameters important for lightning protection, in a form convenient for practical use, is presented in an appendix.

Four years of DNA barcoding: current advances and prospects.

PubMed

Frézal, Lise; Leblois, Raphael

2008-09-01

Research using cytochrome c oxidase barcoding techniques on zoological specimens was initiated by Hebert et al. [Hebert, P.D.N., Ratnasingham, S., deWaard, J.R., 2003. Barcoding animal life: cytochrome c oxidase subunit 1 divergences among closely related species. Proc. R. Soc. Lond. B 270, S96-S99]. By March 2004, the Consortium for the Barcode of Life started to promote the use of a standardized DNA barcoding approach, consisting of identifying a specimen as belonging to a certain animal species based on a single universal marker: the DNA barcode sequence. Over the last 4 years, this approach has become increasingly popular and advances as well as limitations have clearly emerged as increasing amounts of organisms have been studied. Our purpose is to briefly expose DNA Barcode of Life principles, pros and cons, relevance and universality. The initially proposed Barcode of life framework has greatly evolved, giving rise to a flexible description of DNA barcoding and a larger range of applications.

An overview of treatments for obesity in a population with mental illness.

PubMed

Taylor, Valerie H; Stonehocker, Brian; Steele, Margot; Sharma, Arya M

2012-01-01

Obesity is associated with early mortality and has overtaken smoking as the health problem with the greatest impact on quality of life, mortality, and morbidity. Despite public health initiatives and numerous commercial enterprises focusing on weight loss, obesity rates continue to rise. In part, this is because obesity is a multifaceted, complex illness, impacted by numerous social, psychological, and behavioural factors that are unrecognized in most current initiatives. One significant factor associated with obesity is mental illness. While having a psychiatric illness does not make weight gain inevitable, it does often require that additional tools be added to lifestyle recommendations around diet and exercise. The following article reviews the common approaches to obesity management and addresses how these strategies can be implemented in psychiatric care. It is important that health professionals involved in the care of people with a mental illness become familiar with the interventions available to control and treat the obesity epidemic, as this will improve treatment compliance and ultimately lead to improved physical and psychological outcomes.

Innovation in Hospital Revenues: Developing Retail Sales Channels.

PubMed

Wright, Edward W; Marvel, Jon; Wright, Matthew K

Hospitals are facing increasing cost pressures due to cutbacks by Medicare, Medicaid, and managed-care organizations. There are also rising concerns that public policy may exacerbate the problem. In lieu of these concerns, nascent innovative ways of generating increased revenues are beginning to appear. In particular, a few hospitals have adopted retail sales practices to generate significant nonmedical services revenues. The hospital retail sales opportunity has been compared with that of the airport industry where nearly 50% of revenues are generated by sales of retail products as opposed to aeronautical-related transactions. This initial investigation included a qualitative interview of a health care retail sales expert and a pilot survey of 100 hospital senior executives to gauge the current state of this phenomenon. The industry expert suggested that only 2% of US hospitals have pursued this initiative in a meaningful way. Of the 44 survey responses, only 9 institutions were engaged in e-commerce or retail sales activities. Questions remain as to why this opportunity remains unrealized, and additional research is proposed.

Sewage outfall plume dispersion observations with an autonomous underwater vehicle.

PubMed

Ramos, P; Cunha, S R; Neves, M V; Pereira, F L; Quintaneiro, I

2005-01-01

This work represents one of the first successful applications of Autonomous Underwater Vehicles (AUVs) for interdisciplinary coastal research. A monitoring mission to study the shape and estimate the initial dilution of the S. Jacinto sewage outfall plume using an AUV was performed on July 2002. An efficient sampling strategy enabling greater improvements in spatial and temporal range of detection demonstrated that the sewage effluent plume can be clearly traced using naturally occurring tracers in the wastewater. The outfall plume was found at the surface highly influenced by the weak stratification and low currents. Dilution varying with distance downstream was estimated from the plume rise over the outfall diffuser until a nearly constant value of 130:1, 60 m from the diffuser, indicating the near field end. Our results demonstrate that AUVs can provide high-quality measurements of physical properties of effluent plumes in a very effective manner and valuable considerations about the initial mixing processes under real oceanic conditions can be further investigated.

Role of Perturbing Ocean Initial Condition in Simulated Regional Sea Level Change

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

Hu, Aixue; Meehl, Gerald; Stammer, Detlef

Multiple lines of observational evidence indicate that the global climate has been getting warmer since the early 20th century. This warmer climate has led to a global mean sea level rise of about 18 cm during the 20th century, and over 6 cm for the first 15 years of the 21st century. Regionally the sea level rise is not uniform due in large part to internal climate variability. To better serve the community, the uncertainties of predicting/projecting regional sea level changes associated with internal climate variability need to be quantified. Previous research on this topic has used single-model large ensemblesmore » with perturbed atmospheric initial conditions (ICs). Here we compare uncertainties associated with perturbing ICs in just the atmosphere and just the ocean using a state-of-the-art coupled climate model. We find that by perturbing the oceanic ICs, the uncertainties in regional sea level changes increase compared to those with perturbed atmospheric ICs. In order for us to better assess the full spectrum of the impacts of such internal climate variability on regional and global sea level rise, approaches that involve perturbing both atmospheric and oceanic initial conditions are thus necessary.« less

Role of Perturbing Ocean Initial Condition in Simulated Regional Sea Level Change

DOE PAGES

Hu, Aixue; Meehl, Gerald; Stammer, Detlef; ...

2017-06-05

Multiple lines of observational evidence indicate that the global climate has been getting warmer since the early 20th century. This warmer climate has led to a global mean sea level rise of about 18 cm during the 20th century, and over 6 cm for the first 15 years of the 21st century. Regionally the sea level rise is not uniform due in large part to internal climate variability. To better serve the community, the uncertainties of predicting/projecting regional sea level changes associated with internal climate variability need to be quantified. Previous research on this topic has used single-model large ensemblesmore » with perturbed atmospheric initial conditions (ICs). Here we compare uncertainties associated with perturbing ICs in just the atmosphere and just the ocean using a state-of-the-art coupled climate model. We find that by perturbing the oceanic ICs, the uncertainties in regional sea level changes increase compared to those with perturbed atmospheric ICs. In order for us to better assess the full spectrum of the impacts of such internal climate variability on regional and global sea level rise, approaches that involve perturbing both atmospheric and oceanic initial conditions are thus necessary.« less

Religion and World Order: How Are They Related?

ERIC Educational Resources Information Center

Mische, Patricia M.

1997-01-01

The role of spirituality in the rise and fall of civilizations is discussed in the context of three viewpoints about the timeframe of current global systems being transformed: (1) a 50-year timeframe (post-World War II world order); (2) a 500-year timeframe (rise of nation-states); and (3) a 10,000-year timeframe (rise of agriculture and systems…

The pancreatitis-associated protein VMP1, a key regulator of inducible autophagy, promotes Kras(G12D)-mediated pancreatic cancer initiation.

PubMed

Loncle, C; Molejon, M I; Lac, S; Tellechea, J I; Lomberk, G; Gramatica, L; Fernandez Zapico, M F; Dusetti, N; Urrutia, R; Iovanna, J L

2016-07-14

Both clinical and experimental evidence have firmly established that chronic pancreatitis, in particular in the context of Kras oncogenic mutations, predisposes to pancreatic ductal adenocarcinoma (PDAC). However, the repertoire of molecular mediators of pancreatitis involved in Kras-mediated initiation of pancreatic carcinogenesis remains to be fully defined. In this study we demonstrate a novel role for vacuole membrane protein 1 (VMP1), a pancreatitis-associated protein critical for inducible autophagy, in the regulation of Kras-induced PDAC initiation. Using a newly developed genetically engineered model, we demonstrate that VMP1 increases the ability of Kras to give rise to preneoplastic lesions, pancreatic intraepithelial neoplasias (PanINs). This promoting effect of VMP1 on PanIN formation is due, at least in part, by an increase in cell proliferation combined with a decrease in apoptosis. Using chloroquine, an inhibitor of autophagy, we show that this drug antagonizes the effect of VMP1 on PanIN formation. Thus, we conclude that VMP1-mediated autophagy cooperate with Kras to promote PDAC initiation. These findings are of significant medical relevance, molecules targeting autophagy are currently being tested along chemotherapeutic agents to treat PDAC and other tumors in human trials.

Burnout current density of bismuth nanowires

NASA Astrophysics Data System (ADS)

Cornelius, T. W.; Picht, O.; Müller, S.; Neumann, R.; Völklein, F.; Karim, S.; Duan, J. L.

2008-05-01

Single bismuth nanowires with diameters ranging from 100nmto1μm were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density the wires are able to carry was investigated by ramping up the current until failure occurred. It increases by three to four orders of magnitude for nanowires embedded in the template compared to bulk bismuth and rises with diminishing diameter. Simulations show that the wires are heated up electrically to the melting temperature. Since the surface-to-volume ratio rises with diminishing diameter, thinner wires dissipate the heat more efficiently to the surrounding polymer matrix and, thus, can tolerate larger current densities.

Self-pressurization of a flightweight liquid hydrogen tank: Effects of fill level at low wall heat flux

NASA Technical Reports Server (NTRS)

Vandresar, N. T.; Hasan, M. M.; Lin, C.-S.

1991-01-01

Experimental results are presented for the self pressurization and thermal stratification of a 4.89 cu m liquid hydrogen storage tank subjected to low heat flux (2.0 and 3.5 W/sq m) in normal gravity. The test tank was representative of future spacecraft tankage, having a low mass to volume ratio and high performance multilayer thermal insulation. Tests were performed at fill levels of 29 and 49 pcts. (by volume) and complement previous tests at 83 pct. fill. As the heat flux increases, the pressure rise rate at each fill level exceeds the homogeneous rate by an increasing ratio. Herein, this ratio did not exceed a value of 2. The slowest pressure rise rate was observed for the 49 pct. fill level at both heat fluxes. This result is attributed to the oblate spheroidal tank geometry which introduces the variables of wetted wall area, liquid-vapor interfacial area, and ratio of side wall to bottom heating as a function of fill level or liquid depth. Initial tank thermal conditions were found to affect the initial pressure rise rate. Quasi steady pressure rise rates are independent of starting conditions.

"I Love Fruit But I Can't Afford It": Using Participatory Action Research to Develop Community-Based Initiatives to Mitigate Challenges to Chronic Disease Management in an African American Community Living in Public Housing.

PubMed

Rogers, Courtney; Johnson, Joy; Nueslein, Brianne; Edmunds, David; Valdez, Rupa S

2018-03-12

As chronic conditions are on the rise in the USA, management initiatives outside of the inpatient setting should be explored to reduce associated cost and access disparities. Chronic conditions disproportionately affect African American public housing residents due to the effects of historical marginalization on the manifestation of economic and social problems exacerbating health disparities and outcomes. Informed by participatory research action tenets, this study focused on identifying the challenges to management of chronic conditions and developing community-envisioned initiatives to address these challenges in a predominantly African American public housing community. Two focus groups were conducted with former and current public housing residents and were analyzed using inductive content analysis. Physical activity, the cost associated with healthy eating, and lack of information were noted as challenges to chronic disease management. Initiatives discussed were the formation of a walking partner's program to promote physical activity, a shopper's club to exchange coupons and learn how to prepare healthy meals, and a natural remedy's book to share information intergenerationally about management tactics. Challenges identified existed predominantly on the individual and the system level, while the initiatives generated target engaging interpersonal and community relationships. These community-envisioned approaches should be explored to facilitate chronic disease management in public housing neighborhoods.

[Liver transplantation with living donor : current aspects, perspectives and significance in Germany].

PubMed

Settmacher, U; Bauschke, A; Malessa, C; Scheuerlein, H; Zanow, J; Rauchfuß, F

2013-05-01

More than 20 years ago living donor liver transplantation was introduced into clinical practice. Specifics of this method were developed initially for children and later on for adults particularly in regions where a liver transplantation program using deceased donors was not readily available. The most sensitive aspect of living donation, namely the danger to a healthy relative in order to perform the transplantation is immanent in the system and, thus, it is definitively a secondary option as compared to deceased organ donation. Following worldwide initial euphoria the numbers have markedly decreased in the western world since the start of the new millennium. In Asian countries in particular, much work has been done to optimize the procedure so that the donor safety and the outcome quality for the recipient have been impressively demonstrated in large patient populations. There is still a severe donor organ shortage and the option to allocate an optimal (partial) organ on an individual basis by living donation has given new impact to the discussion about a further rise in the profile of living donations here as well. The new version of the German transplantation legislation implemented in summer 2012 requires a number of conditions with respect to insurance for living donors. The current state and perspectives are presented here.

Electron Temperature Evolution During Local Helicity Injection on the Pegasus Toroidal Experiment

NASA Astrophysics Data System (ADS)

Schlossberg, D. J.; Barr, J. L.; Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Perry, J. M.; Reusch, J. A.; Rodriguez Sanchez, C.

2016-10-01

Understanding the electron temperature (Te) evolution during local helicity injection (LHI) is critical for scaling up this non-solenoidal startup technique to MA-class devices. The first comprehensive Te measurements during LHI reveal centrally-peaked profiles with Te > 100 eV for plasma current Ip > 120 kA, toroidal field 0.15 T, and electron density ne 1019 m-3. Te rises and is sustained from just after magnetic relaxation through the plasma decoupling from edge-localized injectors. Results are presented for two injector edge locations: outboard midplane and inboard divertor. Outboard midplane injection couples LHI with inductive drive from poloidal field ramps and radial compression during inward plasma growth. Comparisons of Te at different LHI-to-inductive drive ratios show some profile flattening for higher LHI drive fraction. The latter, constant-shape discharges were necessarily lower performance, with Ip 50 kA and reduced Te , max. Inboard divertor injection achieves higher Ip using minimal inductive drive and thus isolates effects of LHI drive on Te. Initial results in this configuration show Te rising rapidly at the injector location as the discharge grows, settling to a roughly flat profile 100 eV. Thus far, both scenarios provide relatively stable discharges with moderate ne and high-Te, suitable for coupling to auxiliary current drive. Detailed studies of confinement dynamics and discharge optimization are planned for the near future. Work supported by US DOE Grant DE-FG02-96ER54375.

Current molecular markers for gastric progenitor cells and gastric cancer stem cells.

PubMed

Qiao, Xiaotan T; Gumucio, Deborah L

2011-07-01

Gastric stem and progenitor cells (GPC) play key roles in the homeostatic renewal of gastric glands and are instrumental in epithelial repair after injury. Until very recently, the existence of GPC could only be inferred by indirect labeling strategies. The last few years have seen significant progress in the identification of biomarkers that allow prospective identification of GPC. The analysis of these unique cell populations is providing new insights into the molecular underpinnings of gastric epithelial homeostasis and repair. Of closely related interest is the potential to identify so-called cancer stem cells, a rare subpopulation of tumor-initiating cells. Here, we review the current useful biomarkers for GPC, including: (a) those that have been demonstrated by lineage tracing to give rise to all gastric cell lineages (e.g., the villin-transgene marker as well as Lgr5); (b) those that give rise to a subset of gastric lineages (e.g., TFF2); (c) markers that recognize cryptic progenitors for metaplasia (e.g., MIST1), and (d) markers that have not yet been analyzed by lineage tracing (e.g., DCKL1/DCAMKL1, CD133/PROM1, and CD44). The study of these markers has been mostly limited to the mouse model, but the hope is that the rapid pace of recent breakthroughs in this animal model will soon lead to a greater understanding of human gastric stem cell biology and to new insights into gastric cancer, the second leading cause of cancer-related death worldwide.

Particle in cell simulation of peaking switch for breakdown evaluation

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

Umbarkar, Sachin B.; Bindu, S.; Mangalvedekar, H.A.

2014-07-01

Marx generator connected to peaking capacitor and peaking switch can generate Ultra-Wideband (UWB) radiation. A new peaking switch is designed for converting the existing nanosecond Marx generator to a UWB source. The paper explains the particle in cell (PIC) simulation for this peaking switch, using MAGIC 3D software. This peaking switch electrode is made up of copper tungsten material and is fixed inside the hermitically sealed derlin material. The switch can withstand a gas pressure up to 13.5 kg/cm{sup 2}. The lower electrode of the switch is connected to the last stage of the Marx generator. Initially Marx generator (withoutmore » peaking stage) in air; gives the output pulse with peak amplitude of 113.75 kV and pulse rise time of 25 ns. Thus, we design a new peaking switch to improve the rise time of output pulse and to pressurize this peaking switch separately (i.e. Marx and peaking switch is at different pressure). The PIC simulation gives the particle charge density, current density, E counter plot, emitted electron current, and particle energy along the axis of gap between electrodes. The charge injection and electric field dependence on ionic dissociation phenomenon are briefly analyzed using this simulation. The model is simulated with different gases (N{sub 2}, H{sub 2}, and Air) under different pressure (2 kg/cm{sup 2}, 5 kg/cm{sup 2}, 10 kg/cm{sup 2}). (author)« less

Geopolymer concretes: a green construction technology rising from the ash

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

Allouche, E.

2009-07-01

Researchers at Louisiana Tech University have embarked on a multi-year research initiative to develop applications for inorganic polymer concrete, or geopolymer concrete, in the area of civil construction, and to bring solve of these applications to market. One objective was to produce a spray-on coating for use in the harsh environment of wastewater conveyance and treatment facilities. Another project is to establish relationships between fly ash composition and particle size distribution and the mechanical attributes and workability of the resulting geopolymer concrete. A third project is to develop a 'smart' geopolymer concrete whose response to a given electric current canmore » be correlated to the stress level to which the structure is subjected. 1 fig., 6 photos.« less

The scanning tunnelling microscope as an operative tool: doing physics and chemistry with single atoms and molecules.

PubMed

Rieder, Karl-Heinz; Meyer, Gerhard; Hla, Saw-Wai; Moresco, Francesca; Braun, Kai F; Morgenstern, Karina; Repp, Jascha; Foelsch, Stefan; Bartels, Ludwig

2004-06-15

The scanning tunnelling microscope, initially invented to image surfaces down to the atomic scale, has been further developed in the last few years to an operative tool, with which atoms and molecules can be manipulated at will at low substrate temperatures in different manners to create and investigate artificial structures, whose properties can be investigated employing spectroscopic dI/dV measurements. The tunnelling current can be used to selectively break chemical bonds, but also to induce chemical association. These possibilities give rise to startling new opportunities for physical and chemical experiments on the single atom and single molecule level. Here we provide a short overview on recent results obtained with these techniques.

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.

Particle-bearing currents in uniform density and two-layer fluids

NASA Astrophysics Data System (ADS)

Sutherland, Bruce R.; Gingras, Murray K.; Knudson, Calla; Steverango, Luke; Surma, Christopher

2018-02-01

Lock-release gravity current experiments are performed to examine the evolution of a particle bearing flow that propagates either in a uniform-density fluid or in a two-layer fluid. In all cases, the current is composed of fresh water plus micrometer-scale particles, the ambient fluid is saline, and the current advances initially either over the surface as a hypopycnal current or at the interface of the two-layer fluid as a mesopycnal current. In most cases the tank is tilted so that the ambient fluid becomes deeper with distance from the lock. For hypopycnal currents advancing in a uniform density fluid, the current typically slows as particles rain out of the current. While the loss of particles alone from the current should increase the current's buoyancy and speed, in practice the current's speed decreases because the particles carry with them interstitial fluid from the current. Meanwhile, rather than settling on the sloping bottom of the tank, the particles form a hyperpycnal (turbidity) current that advances until enough particles rain out that the relatively less dense interstitial fluid returns to the surface, carrying some particles back upward. When a hypopycnal current runs over the surface of a two-layer fluid, the particles that rain out temporarily halt their descent as they reach the interface, eventually passing through it and again forming a hyperpycnal current. Dramatically, a mesopycnal current in a two-layer fluid first advances along the interface and then reverses direction as particles rain out below and fresh interstitial fluid rises above.

Increasing Health Insurance Costs and the Decline in Insurance Coverage

PubMed Central

Chernew, Michael; Cutler, David M; Keenan, Patricia Seliger

2005-01-01

Objective To determine the impact of rising health insurance premiums on coverage rates. Data Sources & Study Setting Our analysis is based on two cohorts of nonelderly Americans residing in 64 large metropolitan statistical areas (MSAs) surveyed in the Current Population Survey in 1989–1991 and 1998–2000. Measures of premiums are based on data from the Health Insurance Association of America and the Kaiser Family Foundation/Health Research and Educational Trust Survey of Employer-Sponsored Health Benefits. Study Design Probit regression and instrumental variable techniques are used to estimate the association between rising local health insurance costs and the falling propensity for individuals to have any health insurance coverage, controlling for a rich array of economic, demographic, and policy covariates. Principal Findings More than half of the decline in coverage rates experienced over the 1990s is attributable to the increase in health insurance premiums (2.0 percentage points of the 3.1 percentage point decline). Medicaid expansions led to a 1 percentage point increase in coverage. Changes in economic and demographic factors had little net effect. The number of people uninsured could increase by 1.9–6.3 million in the decade ending 2010 if real, per capita medical costs increase at a rate of 1–3 percentage points, holding all else constant. Conclusions Initiatives aimed at reducing the number of uninsured must confront the growing pressure on coverage rates generated by rising costs. PMID:16033490

The Fate of Volatiles in Subaqueous Explosive Eruptions: An Analysis of Steam Condensation in the Water Column

NASA Astrophysics Data System (ADS)

Cahalan, R. C.; Dufek, J.

2015-12-01

A model has been developed to determine the theoretical limits of steam survival in a water column during a subaqueous explosive eruption. Understanding the role of steam dynamics in particle transport and the evolution of the thermal budget is critical to addressing the first order questions of subaqueous eruption mechanics. Ash transport in subaqueous eruptions is initially coupled to the fate of volatile transport. The survival of steam bubbles to the water surface could enable non-wetted ash transport from the vent to a subaerial ash cloud. Current eruption models assume a very simple plume mixing geometry, that cold water mixes with the plume immediately after erupting, and that the total volume of steam condenses in the initial phase of mixing. This limits the survival of steam to within tens of meters above the vent. Though these assumptions may be valid, they are unproven, and the calculations based on them do not take into account any kinetic constraints on condensation. The following model has been developed to evaluate the limits of juvenile steam survival in a subaqueous explosive eruption. This model utilizes the analytical model for condensation of steam injected into a sub-cooled pool produced in Park et al. (2007). Necessary parameterizations require an iterative internal calculation of the steam saturation temperature and vapor density for each modeled time step. The contribution of volumetric expansion due to depressurization of a rising bubble is calculated and used in conjunction with condensation rate to calculate the temporal evolution of bubble volume and radius. Using steam bubble volume with the BBO equation for Lagrangian transport in a fluid, the bubble rise velocity is calculated and used to evaluate the rise distance. The steam rise model proves a useful tool to compare the effects of steam condensation, volumetric expansion, volume flux, and water depth on the dynamics of juvenile steam. The modeled results show that a sufficiently high volatile flux could lead to the survival of steam bubbles from >1km depths to the ocean surface, though low to intermediate fluxes lead to fairly rapid condensation. Building on this result we also present the results of simulations of multiphase steam jets and consider the likelihood of collapse inside a vapor envelope.

Upslope deposition of extremely distal turbidites: An example from the Tiburon Rise, west-central Atlantic

NASA Astrophysics Data System (ADS)

Dolan, James; Beck, Christian; Ogawa, Yujiro

1989-11-01

Terrigenous silt and sand turbidites recovered from the crest of the Tiburon Rise in the west-central Atlantic represent an unprecedented example of upslope turbidite deposition in an extremely distal setting. These Eocene-Oligocene beds, which were derived from South America more than 1000 km to the southeast, were probably deposited by extremely thick (>1500 m) turbidity currents that flowed parallel to the southern margin of the rise. We suggest that flow thickness was the dominant control on deposition of these beds, rather than true upslope flow. This interpretation points out the importance of local bathymetry on the behavior of even extremely distal turbidity currents.

Cancer Drugs: An International Comparison of Postlicensing Price Inflation.

PubMed

Savage, Philip; Mahmoud, Sarah; Patel, Yogin; Kantarjian, Hagop

2017-06-01

The cost of cancer drugs forms a rising proportion of health care budgets worldwide. A number of studies have examined international comparisons of initial cost, but there is little work on postlicensing price increases. To examine this, we compared cancer drug prices at initial sale and subsequent price inflation in the United States and United Kingdom and also reviewed relevant price control mechanisms. The 10 top-selling cancer drugs were selected, and their prices at initial launch and in 2015 were compared. Standard nondiscounted prices were obtained from the relevant annual copies of the RED BOOK and the British National Formulary. At initial marketing, prices were on average 42% higher in the United States than in the United Kingdom. After licensing in the United States, all 10 drugs had price rises averaging an overall annual 8.8% (range, 1.4% to 24.1%) increase. In comparison, in the United Kingdom, six drugs had unchanged prices, two had decreased prices, and two had modest price increases. The overall annual increase in the United Kingdom was 0.24%. Cancer drug prices are rising substantially, both at their initial marketing price and, in the United States, at postlicensing prices. In the United Kingdom, the Pharmaceutical Price Regulation Scheme, an agreement between the government and the pharmaceutical industry, controls health care costs while allowing a return on investment and funds for research. The increasing costs of cancer drugs are approaching the limits of sustainability, and a similar government-industry agreement may allow stability for both health care provision and the pharmaceutical industry in the United States.

Photodiode Preamplifier for Laser Ranging With Weak Signals

NASA Technical Reports Server (NTRS)

Abramovici, Alexander; Chapsky, Jacob

2007-01-01

An improved preamplifier circuit has been designed for processing the output of an avalanche photodiode (APD) that is used in a high-resolution laser ranging system to detect laser pulses returning from a target. The improved circuit stands in contrast to prior such circuits in which the APD output current pulses are made to pass, variously, through wide-band or narrow-band load networks before preamplification. A major disadvantage of the prior wide-band load networks is that they are highly susceptible to noise, which degrades timing resolution. A major disadvantage of the prior narrow-band load networks is that they make it difficult to sample the amplitudes of the narrow laser pulses ordinarily used in ranging. In the improved circuit, a load resistor is connected to the APD output and its value is chosen so that the time constant defined by this resistance and the APD capacitance is large, relative to the duration of a laser pulse. The APD capacitance becomes initially charged by the pulse of current generated by a return laser pulse, so that the rise time of the load-network output is comparable to the duration of the return pulse. Thus, the load-network output is characterized by a fast-rising leading edge, which is necessary for accurate pulse timing. On the other hand, the resistance-capacitance combination constitutes a lowpass filter, which helps to suppress noise. The long time constant causes the load network output pulse to have a long shallow-sloping trailing edge, which makes it easy to sample the amplitude of the return pulse. The output of the load network is fed to a low-noise, wide-band amplifier. The amplifier must be a wide-band one in order to preserve the sharp pulse rise for timing. The suppression of noise and the use of a low-noise amplifier enable the ranging system to detect relatively weak return pulses.

Interferometric Synthetic Aperture Radar to capture spatial variability of local land-based subsidence

NASA Astrophysics Data System (ADS)

Bekaert, D. P.; Hamlington, B.; Buzzanga, B. A.; Jones, C. E.

2017-12-01

The rate of relative sea level rise results from a combination of land subsidence and rising seas associated with global warming on long timescales and exacerbated by shifts in ocean dynamics on shorter timescales. An understanding of the current-day magnitude of each component is needed to create accurate projections of future relative sea level rise upon which to base planning efforts. Current day land-based subsidence rates derived from GPS often lack the spatial resolution to capture the local spatial variability needed when assessing the impact of relative sea-level rise. Interferometric Synthetic Aperture Radar (InSAR) is an attractive technique that has the potential to provide a measurement every 20-30m when good signal coherence is maintained. In practice, coastal regions are challenging for InSAR due to variable vegetation cover and soil moisture, which can be in part mitigated by applying advanced time-series InSAR techniques. After applying time-series InSAR, derived rates need to be combined with GPS to tie relative subsidence rates into a geodetic reference frame. Given the need to make projections of relative sea-level rise it is particularly important to propagate all uncertainties during the different processing stages. Here we provide results from ALOS and Sentinel-1 over Hampton Roads area in the Chesapeake Bay region, which is experiencing one of the highest rates of relative sea level rise on the Atlantic coast of the United States. Although the current derived subsidence rates have large uncertainties, it is expected that this will improve with the decadal observations from Sentinel-1.

The communicative functions of final rises in Finnish intonation.

PubMed

Ogden, Richard; Routarinne, Sara

2005-01-01

This paper considers the communicative function of final rises in Finnish conversational talk between pairs of teenage girls. Final rises are fairly common, occurring approximately twice a minute, predominantly on declaratives and in narrative sequences. We briefly consider the interplay between voice quality (known to be a marker of transition relevance) and rising intonation in Finnish. We argue that in narrative sequences, rising terminals manage two main interactional tasks: they provide a place for a coparticipant to mark recipiency, and they project more talk by the current speaker. Using a methodology which combines phonetic observation with conversation analysis, we demonstrate participants' orientation to these functions.

Mechanisms of sharp wave initiation and ripple generation.

PubMed

Schlingloff, Dániel; Káli, Szabolcs; Freund, Tamás F; Hájos, Norbert; Gulyás, Attila I

2014-08-20

Replay of neuronal activity during hippocampal sharp wave-ripples (SWRs) is essential in memory formation. To understand the mechanisms underlying the initiation of irregularly occurring SWRs and the generation of periodic ripples, we selectively manipulated different components of the CA3 network in mouse hippocampal slices. We recorded EPSCs and IPSCs to examine the buildup of neuronal activity preceding SWRs and analyzed the distribution of time intervals between subsequent SWR events. Our results suggest that SWRs are initiated through a combined refractory and stochastic mechanism. SWRs initiate when firing in a set of spontaneously active pyramidal cells triggers a gradual, exponential buildup of activity in the recurrent CA3 network. We showed that this tonic excitatory envelope drives reciprocally connected parvalbumin-positive basket cells, which start ripple-frequency spiking that is phase-locked through reciprocal inhibition. The synchronized GABA(A) receptor-mediated currents give rise to a major component of the ripple-frequency oscillation in the local field potential and organize the phase-locked spiking of pyramidal cells. Optogenetic stimulation of parvalbumin-positive cells evoked full SWRs and EPSC sequences in pyramidal cells. Even with excitation blocked, tonic driving of parvalbumin-positive cells evoked ripple oscillations. Conversely, optogenetic silencing of parvalbumin-positive cells interrupted the SWRs or inhibited their occurrence. Local drug applications and modeling experiments confirmed that the activity of parvalbumin-positive perisomatic inhibitory neurons is both necessary and sufficient for ripple-frequency current and rhythm generation. These interneurons are thus essential in organizing pyramidal cell activity not only during gamma oscillation, but, in a different configuration, during SWRs. Copyright © 2014 the authors 0270-6474/14/3411385-14$15.00/0.

Agriculture waste and rising CO2

USDA-ARS?s Scientific Manuscript database

Currently, there are many uncertainties concerning agriculture’s role in global environmental change including the effects of rising atmospheric CO2 concentration. A viable and stable world food supply depends on productive agricultural systems, but environmental concerns within agriculture have to...

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.

A Generalized Hydrodynamic-Impact Theory for the Loads and Motions of Deeply Immersed Prismatic Bodies

NASA Technical Reports Server (NTRS)

Markey, Melvin F.

1959-01-01

A theory is derived for determining the loads and motions of a deeply immersed prismatic body. The method makes use of a two-dimensional water-mass variation and an aspect-ratio correction for three-dimensional flow. The equations of motion are generalized by using a mean value of the aspect-ratio correction and by assuming a variation of the two-dimensional water mass for the deeply immersed body. These equations lead to impact coefficients that depend on an approach parameter which, in turn, depends upon the initial trim and flight-path angles. Comparison of experiment with theory is shown at maximum load and maximum penetration for the flat-bottom (0 deg dead-rise angle) model with bean-loading coefficients from 36.5 to 133.7 over a wide range of initial conditions. A dead-rise angle correction is applied and maximum-load data are compared with theory for the case of a model with 300 dead-rise angle and beam-loading coefficients from 208 to 530.

Novel high-frequency, high-power, pulsed oscillator based on a transmission line transformer.

PubMed

Burdt, R; Curry, R D

2007-07-01

Recent analysis and experiments have demonstrated the potential for transmission line transformers to be employed as compact, high-frequency, high-power, pulsed oscillators with variable rise time, high output impedance, and high operating efficiency. A prototype system was fabricated and tested that generates a damped sinusoidal wave form at a center frequency of 4 MHz into a 200 Omega load, with operating efficiency above 90% and peak power on the order of 10 MW. The initial rise time of the pulse is variable and two experiments were conducted to demonstrate initial rise times of 12 and 3 ns, corresponding to a spectral content from 4-30 and from 4-100 MHz, respectively. A SPICE model has been developed to accurately predict the circuit behavior and scaling laws have been identified to allow for circuit design at higher frequencies and higher peak power. The applications, circuit analysis, test stand, experimental results, circuit modeling, and design of future systems are all discussed.

Generations of even-order harmonics from vibrating H2+ and T2+ in the rising and falling parts of the laser field

NASA Astrophysics Data System (ADS)

Feng, Liqiang; Kapteyn, Henry J.; Feng, April Y.

2018-04-01

The generations of the even-order harmonics from H2+ and one of its isotope T2+ have been theoretically investigated beyond the Born-Oppenheimer approximation. Normally, the high-order harmonic generation (HHG) only contains odd-order harmonics for the orbital symmetry along the direction of laser polarization. Here, we showed that due to asymmetric harmonic emission (asymmetric half-wave profile), the even-order harmonics can be generated in the rising and the falling part of the laser field. In detail, in the lower initial vibrational state, the even-order harmonics main come from the falling part of the laser field; while as the initial vibrational state increases, the identified even-order harmonics in the falling part of the laser field are decreased; while some other even-order harmonics coming from the rising part of the laser field can be produced. The interesting phenomena have been proved through studying the spatial distributions and the time profiles of the HHG.

Effect of LED and Argon Laser on Degree of Conversion and Temperature Rise of Hybrid and Low Shrinkage Composite Resins

PubMed Central

Pahlevan, Ayob; Tabatabaei, Masumeh Hasani; Arami, Sakineh; Valizadeh, Sara

2016-01-01

Objectives: Different light curing units are used for polymerization of composite resins. The aim of this study was to evaluate the degree of conversion (DC) and temperature rise in hybrid and low shrinkage composite resins cured by LED and Argon Laser curing lights. Materials and Methods: DC was measured using FTIR spectroscopy. For measuring temperature rise, composite resin samples were placed in Teflon molds and cured from the top. The thermocouple under samples recorded the temperature rise. After initial radiation and specimens reaching the ambient temperature, reirradiation was done and temperature was recorded again. Both temperature rise and DC data submitted to one-way ANOVA and Tukey-HSD tests (5% significance). Results: The obtained results revealed that DC was not significantly different between the understudy composite resins or curing units. Low shrinkage composite resin showed a significantly higher temperature rise than hybrid composite resin. Argon laser caused the lowest temperature rise among the curing units. Conclusion: Energy density of light curing units was correlated with the DC. Type of composite resin and light curing unit had a significant effect on temperature rise due to polymerization and curing unit, respectively. PMID:27843507

Effect of LED and Argon Laser on Degree of Conversion and Temperature Rise of Hybrid and Low Shrinkage Composite Resins.

PubMed

Pahlevan, Ayob; Tabatabaei, Masumeh Hasani; Arami, Sakineh; Valizadeh, Sara

2016-01-01

Different light curing units are used for polymerization of composite resins. The aim of this study was to evaluate the degree of conversion (DC) and temperature rise in hybrid and low shrinkage composite resins cured by LED and Argon Laser curing lights. DC was measured using FTIR spectroscopy. For measuring temperature rise, composite resin samples were placed in Teflon molds and cured from the top. The thermocouple under samples recorded the temperature rise. After initial radiation and specimens reaching the ambient temperature, reirradiation was done and temperature was recorded again. Both temperature rise and DC data submitted to one-way ANOVA and Tukey-HSD tests (5% significance). The obtained results revealed that DC was not significantly different between the understudy composite resins or curing units. Low shrinkage composite resin showed a significantly higher temperature rise than hybrid composite resin. Argon laser caused the lowest temperature rise among the curing units. Energy density of light curing units was correlated with the DC. Type of composite resin and light curing unit had a significant effect on temperature rise due to polymerization and curing unit, respectively.

US power plant sites at risk of future sea-level rise

NASA Astrophysics Data System (ADS)

Bierkandt, R.; Auffhammer, M.; Levermann, A.

2015-12-01

Unmitigated greenhouse gas emissions may increase global mean sea-level by about 1 meter during this century. Such elevation of the mean sea-level enhances the risk of flooding of coastal areas. We compute the power capacity that is currently out-of-reach of a 100-year coastal flooding but will be exposed to such a flood by the end of the century for different US states, if no adaptation measures are taken. The additional exposed capacity varies strongly among states. For Delaware it is 80% of the mean generated power load. For New York this number is 63% and for Florida 43%. The capacity that needs additional protection compared to today increases by more than 250% for Texas, 90% for Florida and 70% for New York. Current development in power plant building points towards a reduced future exposure to sea-level rise: proposed and planned power plants are less exposed than those which are currently operating. However, power plants that have been retired or canceled were less exposed than those operating at present. If sea-level rise is properly accounted for in future planning, an adaptation to sea-level rise may be costly but possible.

A Comprehensive View Of Taiwan Orogeny From TAIGER Perspective

NASA Astrophysics Data System (ADS)

Wu, F. T.; Kuochen, H.; McIntosh, K. D.; Okaya, D. A.; Lavier, L. L.

2012-12-01

Arc-continent collision is one of the basic mechanisms for building continental masses. Taiwan is young and very active. Based on known geology a multi-disciplinary geophysical experiment was designed to image the orogeny in action. Logistics for R/V Langseth, OBS and PASSCAL instruments was complex; nevertheless the field works were completed within the project period. The resulting dataset allows us to map the structures of the shallow crust and the upper mantle. The amount of data gathered is large; some key observations and current interpretations are: (I) Observation: Crustal roots on both Eurasian and Philippine Sea plates, with a high velocity rise in between. Interpretation: Deformation throughout lithosphere on both sides of the initial suture; shortening of lithosphere near plate boundary produce high velocity rise. (II) Observation: Upper mantle high velocity anomaly coincides with a steep east-dippping Wadati-Benioff seismicity in southern Taiwan; the anomaly continues part of the way to central Taiwan but it is aseismic; under northern Taiwan the anomaly is very weak and disorganized. Interpretation: Active subduction in the south (up to 22.8°N) and may be eclogitization in the lower crust and delamination in central Taiwan. (III) Observation: Low Vp/Vs, low resistivity in the core of Central Range. Interp: dry, felsic rocks at relatively high temper (up to 750OC). (IV) Obs: Strong SKS splitting (~2 sec) with trend-parallel fast axis. Interp: Shearing throughout uppermost mantle. Preliminary 2-D geodynamic modeling produces the primary observed features from simple initial model of an arc impinging on continental margin.

Alpha effect of Alfv{acute e}n waves and current drive in reversed-field pinches

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

Litwin, C.; Prager, S.C.

Circularly polarized Alfv{acute e}n waves give rise to an {alpha}-dynamo effect that can be exploited to drive parallel current. In a {open_quotes}laminar{close_quotes} magnetic the effect is weak and does not give rise to significant currents for realistic parameters (e.g., in tokamaks). However, in reversed-field pinches (RFPs) in which magnetic field in the plasma core is stochastic, a significant enhancement of the {alpha} effect occurs. Estimates of this effect show that it may be a realistic method of current generation in the present-day RFP experiments and possibly also in future RFP-based fusion reactors. {copyright} {ital 1998 American Institute of Physics.}

Transport properties of initially neutral gas disturbed by intense electron beam

NASA Astrophysics Data System (ADS)

Angus, Justin; Swanekamp, Steve; Schumer, Joseph; Mosher, Dave; Ottinger, Paul

2013-10-01

The behavior of intense electron beams (those with current densities on the order of hundreds of kA/cm2 and beam rise times on the order of 100 ns) traveling through gaseous mediums depends strongly on the transport properties of the medium. For example, the conductivity of the medium, which is very sensitive to the ionization state and temperature of the gas, has a strong influence on the beam behavior through the plasma return current. Since the beam is responsible for ionizing and heating the gas, self-consistently solving for the gas transport properties and the beam propagation is essential for an accurate description of the system. An advanced gas chemistry model to describe the transport properties of a strongly disturbed gaseous system is presented in this work. A focal point of this work is an accurate description of the medium's conductivity as the gas progresses from its weakly ionized state, where swarm models are valid, to a strongly ionized state where the Spitzer-Harm model applies. NRL Karle Fellowship

Effects of solution volume on hydrogen production by pulsed spark discharge in ethanol solution

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

Xin, Y. B.; Sun, B., E-mail: sunb88@dlmu.edu.cn; Zhu, X. M.

2016-07-15

Hydrogen production from ethanol solution (ethanol/water) by pulsed spark discharge was optimized by varying the volume of ethanol solution (liquid volume). Hydrogen yield was initially increased and then decreased with the increase in solution volume, which achieved 1.5 l/min with a solution volume of 500 ml. The characteristics of pulsed spark discharge were studied in this work; the results showed that the intensity of peak current, the rate of current rise, and energy efficiency of hydrogen production can be changed by varying the volume of ethanol solution. Meanwhile, the mechanism analysis of hydrogen production was accomplished by monitoring the process of hydrogenmore » production and the state of free radicals. The analysis showed that decreasing the retention time of gas production and properly increasing the volume of ethanol solution can enhance the hydrogen yield. Through this research, a high-yield and large-scale method of hydrogen production can be achieved, which is more suitable for industrial application.« less

Discrete Element Model for Simulations of Early-Life Thermal Fracturing Behaviors in Ceramic Nuclear Fuel Pellets

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

Hai Huang; Ben Spencer; Jason Hales

2014-10-01

A discrete element Model (DEM) representation of coupled solid mechanics/fracturing and heat conduction processes has been developed and applied to explicitly simulate the random initiations and subsequent propagations of interacting thermal cracks in a ceramic nuclear fuel pellet during initial rise to power and during power cycles. The DEM model clearly predicts realistic early-life crack patterns including both radial cracks and circumferential cracks. Simulation results clearly demonstrate the formation of radial cracks during the initial power rise, and formation of circumferential cracks as the power is ramped down. In these simulations, additional early-life power cycles do not lead to themore » formation of new thermal cracks. They do, however clearly indicate changes in the apertures of thermal cracks during later power cycles due to thermal expansion and shrinkage. The number of radial cracks increases with increasing power, which is consistent with the experimental observations.« less

Using Groundwater Modeling to Evaluate Impacts of Sea Level Rise on A Coastal Riverine Ecosystem: A Case Study of Saint Jones River Water Shed

NASA Astrophysics Data System (ADS)

He, C.; McKenna, T. E.

2016-12-01

A 3-D, transient, variable-density groundwater flow model (SEAWAT) is used to simulate the groundwater response to predicted sea level rise in the Saint Jones River watershed adjacent to the Delaware Estuary. Sea level rise directly leads to substantial changes in the depth of water table, and these changes can extend far inland due to the long tidal rivers in this area. This research studied the impacts of three different sea level rise scenarios (0.5m, 1.0m and 1.5m) on two concerned aspects in the area: failure of septic tank system and loss of agriculture land. The model results indicate that 1) 10% 13% of current existing septic tank will fail as the water table rise to less than 1.5meters from land surface, and 2) approximate 271 to 927 acres of agriculture land, which covers about 4% 13% of total current agriculture land in the study area, will be lost due to water table rise above the effective rooting depth. To count in the uncertainty of climate change in the future, Monte Carlo simulation was applied and a linear transformation model was created and verified to facilitate the tremendous computation.

Simulation of chain of quenches on toroidal HTS-SMES taking account of thermal and electromagnetic characteristics

NASA Astrophysics Data System (ADS)

Oga, Y.; Noguchi, S.; Igarashi, H.

When a temperature rise occurs at a local area inside a coil of toroidal HTS-SMES by any reason, a temperature hotspot which results in a thermal runaway appears at the local area. Subsequently, after appearing the local normal zone in the HTS coil, the transport current of the HTS coil decrease since the resistance of HTS coil appears and the current partially flows into a parallel-connecting shunt resistance. However, if the transport current of the normal-transitioned HTS coil is hardly changed, the temperature on the hotspot would rise more and then the normal zone would spread rapidly. It may cause a serious accident due to high stored energy. Therefore, using the numerical simulation, we have investigated the behaviors of the coil current, the critical current, and the temperature in the superconducting element coils of HTS-SMES. Consequently, the temperature of the superconducting element coils rises up extremely when a large heat is generated at a certain area of one of them by any reason. Moreover, there is a possibility that the shunt resister hardly functions for protection since the coil is burned out due to high inductances and low resistance of the superconducting element coil.

The Association of Family Influence and Initial Interest in Science

ERIC Educational Resources Information Center

Dabney, Katherine P.; Chakraverty, Devasmita; Tai, Robert H.

2013-01-01

With recent attention to improving scientific workforce development and student achievement, there has been a rise in effort to understand and encourage student engagement in physical science. This study examines the association of family influence and initial interest in science through multiple and logistic regression models. Research questions…

Form and function of the bulbus arteriosus in yellowfin tuna (Thunnus albacares), bigeye tuna (Thunnus obesus) and blue marlin (Makaira nigricans): static properties.

PubMed

Braun, Marvin H; Brill, Richard W; Gosline, John M; Jones, David R

2003-10-01

The juxtaposition of heart and gills in teleost fish means that the Windkessel function characteristic of the whole mammalian arterial tree has to be subserved by the extremely short ventral aorta and bulbus arteriosus. Over the functional pressure range, arteries from blue marlin (Makaira nigricans) and yellowfin tuna (Thunnus albacares) have J-shaped pressure-volume (P-V) loops, while bulbi from the same species have r-shaped P-V loops, with a steep initial rise followed by a compliant plateau phase. The steep initial rise in pressure is due to the geometry of the lumen. The interactions between radius, pressure and tension require a large initial pressure to open the bulbar lumen for flow. The plateau is due to the unique organization of the bulbar wall. The large elastin:collagen ratio, limited amount of collagen arranged circumferentially, lack of elastin lamellae and low hydrophobicity of the elastin itself all combine to lower stiffness, increase extensibility and allow efficient recoil. Even though the modulus of bulbus material is much lower than that of an artery, at large volumes the overall stiffness of the bulbus increases rapidly. The morphological features that give rise to the special inflation characteristics of the bulbus help to extend flow and maintain pressure during diastole.

Linking research to practice: the rise of evidence-based health sciences librarianship.

PubMed

Marshall, Joanne Gard

2014-01-01

The lecture explores the origins of evidence-based practice (EBP) in health sciences librarianship beginning with examples from the work of Janet Doe and past Doe lecturers. Additional sources of evidence are used to document the rise of research and EBP as integral components of our professional work. FOUR SOURCES OF EVIDENCE ARE USED TO EXAMINE THE RISE OF EBP: (1) a publication by Doe and research-related content in past Doe lectures, (2) research-related word usage in articles in the Bulletin of the Medical Library Association and Journal of the Medical Library Association between 1961 and 2010, (3) Medical Library Association activities, and (4) EBP as an international movement. These sources of evidence confirm the rise of EBP in health sciences librarianship. International initiatives sparked the rise of evidence-based librarianship and continue to characterize the movement. This review shows the emergence of a unique form of EBP that, although inspired by evidence-based medicine (EBM), has developed its own view of evidence and its application in library and information practice. Health sciences librarians have played a key role in initiating, nurturing, and spreading EBP in other branches of our profession. Our close association with EBM set the stage for developing our own EBP. While we relied on EBM as a model for our early efforts, we can observe the continuing evolution of our own unique approach to using, creating, and applying evidence from a variety of sources to improve the quality of health information services.

Salt diapirs in the Dead Sea basin and their relationship to Quaternary extensional tectonics

USGS Publications Warehouse

Al-Zoubi, A.; ten Brink, Uri S.

2001-01-01

Regional extension of a brittle overburden and underlying salt causes differential loading that is thought to initiate the rise of reactive diapirs below and through regions of thin overburden. We present a modern example of a large salt diapir in the Dead Sea pull-apart basin, the Lisan diapir, which we believe was formed during the Quaternary due to basin transtension and subsidence. Using newly released seismic data that are correlated to several deep wells, we determine the size of the diapir to be 13 x 10 km. its maximum depth 7.2 km. and its roof 125 m below the surface. From seismic stratigraphy, we infer that the diapir started rising during the early to middle Pleistocene as this section of the basin underwater rapid subsidence and significant extension of the overburden. During the middle to late Pleistocene, the diapir pierced through the extensionally thinned overburden, as indicated by rim synclines, which attest to rapid salt withdrawal from the surrounding regions. Slight positive topography above the diapir and shallow folded horizons indicate that it is still rising intermittently. The smaller Sedom diapir, exposed along the western bounding fault of the basin is presently rising and forms a 200 m-high ridge. Its initiation is explained by localized E-W extension due monoclinal draping over the edge of a rapidly subsiding basin during the early to middle Pleistocene, and its continued rise by lateral squeezing due to continued rotation of the Amazyahu diagonal fault. 

Experimental and analytical investigation on metal damage suffered from simulated lightning currents

NASA Astrophysics Data System (ADS)

Yakun, LIU; Zhengcai, FU; Quanzhen, LIU; Baoquan, LIU; Anirban, GUHA

2017-12-01

The damage of two typical metal materials, Al alloy 3003 and steel alloy Q235B, subjected to four representative lightning current components are investigated by laboratory and analytical studies to provide fundamental data for lightning protection. The four lightning components simulating the natural lightning consist of the first return stroke, the continuing current of interval stroke, the long continuing current, and the subsequent stroke, with amplitudes 200 kA, 8 kA, 400 A, and 100 kA, respectively. The damage depth and area suffered from different lightning components are measured by the ultrasonic scanning system. And the temperature rise is measured by the thermal imaging camera. The results show that, for both Al 3003 and steel Q235B, the first return stroke component results in the largest damage area with damage depth 0.02 mm uttermost. The long continuing current component leads to the deepest damage depth of 3.3 mm for Al 3003 and much higher temperature rise than other components. The correlation analysis between damage results and lightning parameters indicates that the damage depth has a positive correlation with charge transfer. The damage area is mainly determined by the current amplitude and the temperature rise increases linearly with the charge transfer larger.

Inductive flux usage and its optimization in tokamak operation

DOE PAGES

Luce, Timothy C.; Humphreys, David A.; Jackson, Gary L.; ...

2014-07-30

The energy flow from the poloidal field coils of a tokamak to the electromagnetic and kinetic stored energy of the plasma are considered in the context of optimizing the operation of ITER. The goal is to optimize the flux usage in order to allow the longest possible burn in ITER at the desired conditions to meet the physics objectives (500 MW fusion power with energy gain of 10). A mathematical formulation of the energy flow is derived and applied to experiments in the DIII-D tokamak that simulate the ITER design shape and relevant normalized current and pressure. The rate ofmore » rise of the plasma current was varied, and the fastest stable current rise is found to be the optimum for flux usage in DIII-D. A method to project the results to ITER is formulated. The constraints of the ITER poloidal field coil set yield an optimum at ramp rates slower than the maximum stable rate for plasmas similar to the DIII-D plasmas. Finally, experiments in present-day tokamaks for further optimization of the current rise and validation of the projections are suggested.« less

Mechanism of formation of subnanosecond current front in high-voltage pulse open discharge

NASA Astrophysics Data System (ADS)

Schweigert, I. V.; Alexandrov, A. L.; Zakrevsky, Dm. E.; Bokhan, P. A.

2014-11-01

The mechanism of subnanosecond current front rise observed previously in the experiment in high-voltage pulse open discharge in helium is studied in kinetic particle-in-cell simulations. The Boltzmann equations for electrons, ions, and fast atoms are solved self-consistently with the Poisson equations for the electrical potential. The partial contributions to the secondary electron emission from the ions, fast atoms, photons, and electrons, bombarding the electrode, are calculated. In simulations, as in the experiment, the discharge glows between two symmetrical cathodes and the anode grid in the midplane at P =6 Torr and the applied voltage of 20 kV. The electron avalanche development is considered for two experimental situations during the last stage of breakdown: (i) with constant voltage and (ii) with decreasing voltage. For case (i), the subnanosecond current front rise is set by photons from the collisional excitation transfer reactions. For the case (ii), the energetic electrons swamp the cathode during voltage drop and provide the secondary electron emission for the subnanosecond current rise, observed in the experiment.

Dual current readout for precision plating

NASA Technical Reports Server (NTRS)

Iceland, W. F.

1970-01-01

Bistable amplifier prevents damage in the low range circuitry of a dual scale ammeter. It senses the current and switches automatically to the high range circuitry as the current rises above a preset level.

Modelling the Holderness coast, eastern England: Past, present and future

NASA Astrophysics Data System (ADS)

Barkwith, A.; Limber, P. W.; Thomas, C. W.; Murray, A.; Jordan, H. M.; Ellis, M. A.

2012-12-01

The Holderness coast of eastern Yorkshire, England, is the most rapidly eroding coastline in Europe. Erosion can locally exceed 10 m in a single year and rates average 0.5 to 3 m yr-1, generally increasing from north to south. Pinned in the north by a chalk headland, the soft till coastline has a characteristic open spiral form terminated by a spit to the south. Erosion currently threatens local communities and infrastructure, including nationally important gas installations. Interventions to restrict local erosion usually result in enhanced erosion in adjacent, unprotected sections of coast, mirroring morphology seen on the large scale. We have initiated a modelling study to investigate the key controls on the form and evolution of this coastline, and its response to climate change, building on the Coastline Evolution Model (CEM) developed at Duke University, NC. We have adapted the CEM to permit an ensemble of simulations to be undertaken, based upon modified offshore wave climates, initial conditions and forcing factors. The CEM follows a standard 1d approach, where the cross-shore is collapsed into a single data point, allowing the planform shoreline shape and dynamics to be simulated. The model facilitates study of a coast with variable erosion rates, and enables simulation of coastline evolution when sediment is supplied from an eroding shoreface. Additionally, the CEM is adapted to use an observed two year, offshore wave climate data set as input. Initial work focussed on reconstruction of current coastline shape from an ensemble of hypothetical early Holocene shoreface positions and past wave climates. First order reconstruction of shoreline shape was achieved using several differing initial conditions and wave climates. For the majority of successful simulations, a steady state was noted for proceeding years, where erosion proceeds at an equal rate along the length of the coast south of the headland. Together with a sensitivity analysis, the derivation of the current coastline provided initial conditions for the second phase of the work: simulating the morphological response of the Holderness coastline to possible future changes in climate over the next century. An ensemble of future possible wave climate perturbations was generated from predictions of the likely response of the North Sea to future climate change over the next century, and applied linearly to the observed wave climate as each simulation progressed. The ensemble output was compared to a baseline simulation, run for a century under current wave climate, to assess the impact of predicted future climate on coastal erosion. Although this study does not currently take into account the changes in storm frequency, rises in sea level or the anthropogenic inputs that could influence the results, the initial output indicates erosional rates over the next century are likely to be retarded for the Holderness coastline under a changing climate.

Sun Radio Interferometer Space Experiment (SunRISE)

NASA Astrophysics Data System (ADS)

Kasper, Justin C.; SunRISE Team

2018-06-01

The Sun Radio Interferometer Space Experiment (SunRISE) is a NASA Heliophysics Explorer Mission of Opportunity currently in Phase A. SunRISE is a constellation of spacecraft flying in a 10-km diameter formation and operating as the first imaging radio interferometer in space. The purpose of SunRISE is to reveal critical aspects of solar energetic particle (SEP) acceleration at coronal mass ejections (CMEs) and transport into space by making the first spatially resolved observations of coherent Type II and III radio bursts produced by electrons accelerated at CMEs or released from flares. SunRISE will focus on solar Decametric-Hectometric (DH, 0.1 < f < 15 MHz) radio bursts that always are detected from space before major SEP events, but cannot be seen on Earth due to ionospheric absorption. This talk will describe SunRISE objectives and implementation. Presented on behalf of the entire SunRISE team.

The Voltage Distribution Characteristics of a Hybrid Circuit Breaker During High Current Interruption

NASA Astrophysics Data System (ADS)

Cheng, Xian; Duan, Xiongying; Liao, Minfu; Huang, Zhihui; Luo, Yan; Zou, Jiyan

2013-08-01

Hybrid circuit breaker (HCB) technology based on a vacuum interrupter and a SF6 interrupter in series has become a new research direction because of the low-carbon requirements for high voltage switches. The vacuum interrupter has an excellent ability to deal with the steep rising part of the transient recovery voltage (TRV), while the SF6 interrupter can withstand the peak part of the voltage easily. An HCB can take advantage of the interrupters in the current interruption process. In this study, an HCB model based on the vacuum ion diffusion equations, ion density equation, and modified Cassie-Mayr arc equation is explored. A simulation platform is constructed by using a set of software called the alternative transient program (ATP). An HCB prototype is also designed, and the short circuit current is interrupted by the HCB under different action sequences of contacts. The voltage distribution of the HCB is analyzed through simulations and tests. The results demonstrate that if the vacuum interrupter withstands the initial TRV and interrupts the post-arc current first, then the recovery speed of the dielectric strength of the SF6 interrupter will be fast. The voltage distribution between two interrupters is determined by their post-arc resistance, which happens after current-zero, and subsequently, it is determined by the capacitive impedance after the post-arc current decays to zero.

The Physics of Twisted Magnetic Tubes Rising in a Stratified Medium: Two-dimensional Results

NASA Astrophysics Data System (ADS)

Emonet, T.; Moreno-Insertis, F.

1998-01-01

The physics of a twisted magnetic flux tube rising in a stratified medium is studied using a numerical magnetohydrodynamic (MHD) code. The problem considered is fully compressible (has no Boussinesq approximation), includes ohmic resistivity, and is two-dimensional, i.e., there is no variation of the variables in the direction of the tube axis. We study a high-plasma β-case with a small ratio of radius to external pressure scale height. The results obtained will therefore be of relevance to understanding the transport of magnetic flux across the solar convection zone. We confirm that a sufficient twist of the field lines around the tube axis can suppress the conversion of the tube into two vortex rolls. For a tube with a relative density deficit on the order of 1/β (the classical Parker buoyancy) and a radius smaller than the pressure scale height (R2<

Size and structure evolution of kaolin-Al(OH)3 flocs in the electroflocculation process: a study using static light scattering.

PubMed

Harif, T; Adin, A

2011-11-15

Electroflocculation (EF) is gaining recognition as an alternative process to conventional coagulation/flocculation. The electrical current applied in EF that generates the active coagulant species creates a unique chemical/physical environment in which competing redox reactions occur, primarily water electrolysis. This causes a transient rise in pH, due to cathodic formation of hydroxyl ions, which, in turn, causes a continuous shift in coagulation/flocculation mechanisms throughout the process. This highly impacts the formation of a sweep floc regime that relies on precipitation of metal hydroxide and its growth into floc. The size and structural evolution of kaolin-Al(OH)(3) flocs was examined using static light scattering techniques, in aim of elucidating kinetic aspects of the process. An EF cell was operated in batch mode and comprised of two concentric electrodes - a stainless steel cathode (inner electrode) and an aluminum anode (outer electrode). The cell was run at constant current between 0.042A and 0.22A, and analyses performed at pre-determined time intervals. The results demonstrate that EF is able to generate a range of flocs, exhibiting different growth rates and structural characteristics, depending on the conditions of operation. Growth patterns were sigmoidal and a linear correlation between growth rate and current applied was observed. The dependency of growth rate on current can be related to initial pH and aluminum dosing, with a stronger dependency apparent for initial optimal sweep floc regime. All flocs exhibited a fragile nature and undergo compaction and structural fluctuations during growth. This is the first time size and structural evolution of flocs formed in the EF process is reported. Copyright © 2011 Elsevier Ltd. All rights reserved.

Current issues in atmospheric change

NASA Technical Reports Server (NTRS)

1987-01-01

In response to questions about the effects of long-term, global-scale changes in the atmosphere raised in congressional hearings, a group of leading experts held a two-day workshop to survey the state of current knowledge about atmospheric changes and their implications. The review focuses on the sources, concentrations, and changes of those gases most directly linked to human activities, i.e., carbon dioxide, ozone, and the chlorofluorocarbons; the direct physical effects of rising concentrations of trace gases. The review discusses the uncertainties associated with the knowledge of current trends and possible future changes, including ozone trends and the Antarctic ozone hole, and the impacts of rising concentrations of trace gases.

Coastline Mapping and Cultural Review to Predict Sea Level Rise Impact on Hawaiian Archeological Sites

NASA Astrophysics Data System (ADS)

Clinton, J.

2017-12-01

Much of Hawaii's history is recorded in archeological sites. Researchers and cultural practitioners have been studying and reconstructing significant archeological sites for generations. Climate change, and more specifically, sea level rise may threaten these sites. Our research records current sea levels and then projects possible consequences to these cultural monuments due to sea level rise. In this mixed methods study, research scientists, cultural practitioners, and secondary students use plane-table mapping techniques to create maps of coastlines and historic sites. Students compare historical records to these maps, analyze current sea level rise trends, and calculate future sea levels. They also gather data through interviews with community experts and kupuna (elders). If climate change continues at projected rates, some historic sites will be in danger of negative impact due to sea level rise. Knowing projected sea levels at specific sites allows for preventative action and contributes to raised awareness of the impacts of climate change to the Hawaiian Islands. Students will share results with the community and governmental agencies in hopes of inspiring action to minimize climate change. It will take collaboration between scientists and cultural communities to inspire future action on climate change.

Advertising to children initiatives have not reduced unhealthy food advertising on Australian television.

PubMed

Watson, Wendy L; Lau, Vivien; Wellard, Lyndal; Hughes, Clare; Chapman, Kathryn

2017-12-01

In response to rising childhood obesity rates, the Australian food industry implemented two initiatives in 2009 to reduce the marketing of unhealthy food to children. This study evaluated the efficacy of these initiatives on the rate of unhealthy food advertising to children on Australian television. The rates of food advertisements on three free-to-air commercial television channels and a youth-oriented digital channel in Sydney, Australia were analysed over 2 weekdays (16 h) and two weekend days (22 h). Advertisements were categorized according to the healthiness of foods advertised (non-core, core, miscellaneous) and signatory status to the food industry advertising initiatives. Total food advertising rates for the three channels increased from 5.5/h in 2011 to 7.3/h in 2015, due to an increase of 0.8/h for both core and miscellaneous foods. The rate of non-core food advertisements in 2015 (3.1/h) was similar to 2011 (3.0/h). The youth-oriented channel had fewer total food advertisements (3.7/h versus 7.3/h) but similar fast-food advertisement rates (1.3/h versus 1.3/h). There was no change in the rate of unhealthy food advertising since 2011, suggesting minimal impact of the current food industry initiatives on reducing children's exposure to unhealthy food advertising. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Photoacoustic imaging in both soft and hard biological tissue

NASA Astrophysics Data System (ADS)

Li, T.; Dewhurst, R. J.

2010-03-01

To date, most Photoacoustic (PA) imaging results have been from soft biotissues. In this study, a PA imaging system with a near-infrared pulsed laser source has been applied to obtain 2-D and 3-D images from both soft tissue and post-mortem dental samples. Imaging results showed that the PA technique has the potential to image human oral disease, such as early-stage teeth decay. For non-invasive photoacoustic imaging, the induced temperature and pressure rises within biotissues should not cause physical damage to the tissue. Several simulations based on the thermoelastic effect have been applied to predict initial temperature and pressure fields within a tooth sample. Predicted initial temperature and pressure rises are below corresponding safety limits.

The Global Education Agenda and the Delivery of Aid to Pacific Education

ERIC Educational Resources Information Center

Coxon, Eve; Munce, Karen

2008-01-01

In recent years the international development community's concern to redress the apparent failure of half a century of "development" efforts, has given rise to a number of global initiatives aimed at both reducing worldwide poverty and enhancing international security. One outcome of these initiatives has been a refocusing on the…

Facilitating Transfer: An Issue of the 90's.

ERIC Educational Resources Information Center

Coleman, Catherine

Recently the state legislatures in Texas and Arkansas have passed initiatives to maximize transfer effectiveness from two- to four-year institutions. These initiatives, and others being undertaken on a national level, were stimulated by the rising cost of higher education, a decline in transfer rates and low achievement among students who do…

Comparing initial diagnostic excision biopsy of cutaneous malignant melanoma in primary versus secondary care: A study of Irish National data.

PubMed

Doherty, Sarah M; Jackman, Louise M; Kirwan, John F; Dunne, Deirdre; O'Connor, Kieran G; Rouse, John M

2016-12-01

The incidence of melanoma is rising worldwide. Current Irish guidelines from the National Cancer Control Programme state suspicious pigmented lesions should not be removed in primary care. There are conflicting guidelines and research advising who should remove possible melanomas. To determine whether initial diagnostic excision biopsy of cutaneous malignant melanoma in primary versus secondary care leads to poorer survival. Analysis of data comprising 7116 cases of cutaneous malignant melanoma from the National Cancer Registry Ireland between January 2002 and December 2011. Single predictor variables were examined by the chi-square or Mann-Whitney U test. The effects of single predictor variables on survival were examined by Cox proportionate hazards modelling and a multivariate Cox model of survival based on excision in a non-hospital setting versus hospital setting was derived with adjusted and unadjusted hazard ratios. Over a 10-year period 8.5% of melanomas in Ireland were removed in a non-hospital setting. When comparing melanoma death between the hospital and non-hospital groups, the adjusted hazard ratio was 1.56 (95%CI: 1.08-2.26); (P = .02), indicating a non-inferior outcome for the melanoma cases initially treated in the non-hospital group, after adjustment for significant covariates. This study suggests that initial excision biopsy carried out in general practice does not lead to a poorer outcome. [Box: see text].

Is Exposure to Tobacco Advertising, Promotion and Sponsorship Associated with Initiation of Tobacco Use among Current Tobacco Users in Youth in India?

PubMed

Sardana, Mohini; Goel, Sonu; Gupta, Madhu; Sardana, Veera; Singh, B S

2015-01-01

The rise in consumption of tobacco products among youth is a public health concern in India. Several studies have shown that advertisements promoting tobacco products influence decisions and behaviour of youth towards smoking. To ascertain which method of Tobacco Advertising, Promotion and Sponsorship (TAPS) was more influential for initiating tobacco use in youth in India. The secondary data of youth (15-24 years) from nationally representative Global Adult Tobacco Survey (GATS) conducted in 2009-2010 was analyzed. Odds ratio and p-value were used to know the association between TAPS and initiation of use of tobacco products among youth. Logistic regression was used to determine the most significant means of TAPS altering the youth's behaviour towards tobacco products. Out of 13,383 youths, 1,982 (14.7%) used smokeless forms of tobacco and 860 (6.38%) used smoke forms. Logistic regression reveals that promotional activities mainly through cinemas (p<0.05) and providing free samples of tobacco products (p<=.001) were most influential means of initiating consumption of tobacco products among youth. The smoking in youth is associated with watching advertisements particularly in cinema and promotional activities like distribution of free samples, coupons and sales on the price of tobacco products. Stronger legislative measures should be enforced to curb promotional advertisements in cinemas and distribution of free samples.

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.

Bottom currents and sediment waves on a shallow carbonate shelf, Northern Carnarvon Basin, Australia

NASA Astrophysics Data System (ADS)

Belde, Johannes; Reuning, Lars; Back, Stefan

2017-04-01

The modern seafloor of the Australian Northwest Shelf between Exmouth and Dampier was analyzed for large scale sedimentary bedforms on 3D seismic reflection data. The Carnarvon MegaSurvey of Petroleum Geo-Services (PGS), a merged dataset of multiple industrial 3D seismic reflection surveys with a total size of 49,717 km2, offers an extensive view of the continental shelf, slope and rise of the Northern Carnarvon Basin. Over the shelf two fields of large scale sediment waves were observed in water depths between 55-130 m, where the seafloor may be influenced by different processes including internal waves, tides and storms. Based on the dimensions and orientations of the sediment waves the dominant direction and approximate strength of local bottom currents could be estimated. Information on local sediment grain-size distribution was provided by the auSEABED database allowing a classification of the observed sediment waves into sand- or mudwaves. The first sediment wave field is positioned northwest of the Montebello Islands where the shelf is comparatively narrow and local sediment is mainly sand-sized. It most likely formed by increased bottom currents induced by the diversion of tidal flows around the islands. The second sediment wave field is located north of the Serrurier and Bessieres Islands within a local seafloor depression. Local sediments are poorly sorted, containing significant amounts of mud and gravel in addition to the mainly sand-sized grains. The coarser sediment fraction could have been reworked to sandwaves by cyclone-induced bottom currents. Alternatively, the finer sediment fraction could form mudwaves shaped by less energetic along-slope oriented currents in the topographic depression. The sediment waves consist partially of carbonate grains such as ooids and peloids that formed in shallow water during initial stages of the post glacial sea-level rise. These stranded carbonate grains thus formed in a different environment than the sediment waves in which they were redeposited. In fossil examples of similar high-energy ramp systems this possible out-of-equilibrium relationship between grains and bedforms has to be taken into account for the interpretation of the depositional environment.

Committed sea-level rise for the next century from Greenland ice sheet dynamics during the past decade

PubMed Central

Price, Stephen F.; Payne, Antony J.; Howat, Ian M.; Smith, Benjamin E.

2011-01-01

We use a three-dimensional, higher-order ice flow model and a realistic initial condition to simulate dynamic perturbations to the Greenland ice sheet during the last decade and to assess their contribution to sea level by 2100. Starting from our initial condition, we apply a time series of observationally constrained dynamic perturbations at the marine termini of Greenland’s three largest outlet glaciers, Jakobshavn Isbræ, Helheim Glacier, and Kangerdlugssuaq Glacier. The initial and long-term diffusive thinning within each glacier catchment is then integrated spatially and temporally to calculate a minimum sea-level contribution of approximately 1 ± 0.4 mm from these three glaciers by 2100. Based on scaling arguments, we extend our modeling to all of Greenland and estimate a minimum dynamic sea-level contribution of approximately 6 ± 2 mm by 2100. This estimate of committed sea-level rise is a minimum because it ignores mass loss due to future changes in ice sheet dynamics or surface mass balance. Importantly, > 75% of this value is from the long-term, diffusive response of the ice sheet, suggesting that the majority of sea-level rise from Greenland dynamics during the past decade is yet to come. Assuming similar and recurring forcing in future decades and a self-similar ice dynamical response, we estimate an upper bound of 45 mm of sea-level rise from Greenland dynamics by 2100. These estimates are constrained by recent observations of dynamic mass loss in Greenland and by realistic model behavior that accounts for both the long-term cumulative mass loss and its decay following episodic boundary forcing. PMID:21576500

Committed sea-level rise for the next century from Greenland ice sheet dynamics during the past decade.

PubMed

Price, Stephen F; Payne, Antony J; Howat, Ian M; Smith, Benjamin E

2011-05-31

We use a three-dimensional, higher-order ice flow model and a realistic initial condition to simulate dynamic perturbations to the Greenland ice sheet during the last decade and to assess their contribution to sea level by 2100. Starting from our initial condition, we apply a time series of observationally constrained dynamic perturbations at the marine termini of Greenland's three largest outlet glaciers, Jakobshavn Isbræ, Helheim Glacier, and Kangerdlugssuaq Glacier. The initial and long-term diffusive thinning within each glacier catchment is then integrated spatially and temporally to calculate a minimum sea-level contribution of approximately 1 ± 0.4 mm from these three glaciers by 2100. Based on scaling arguments, we extend our modeling to all of Greenland and estimate a minimum dynamic sea-level contribution of approximately 6 ± 2 mm by 2100. This estimate of committed sea-level rise is a minimum because it ignores mass loss due to future changes in ice sheet dynamics or surface mass balance. Importantly, > 75% of this value is from the long-term, diffusive response of the ice sheet, suggesting that the majority of sea-level rise from Greenland dynamics during the past decade is yet to come. Assuming similar and recurring forcing in future decades and a self-similar ice dynamical response, we estimate an upper bound of 45 mm of sea-level rise from Greenland dynamics by 2100. These estimates are constrained by recent observations of dynamic mass loss in Greenland and by realistic model behavior that accounts for both the long-term cumulative mass loss and its decay following episodic boundary forcing.

The Impact of Sea Level Rise on Florida's Everglades

NASA Astrophysics Data System (ADS)

Senarath, S. U.

2005-12-01

Global warming and the resulting melting of polar ice sheets could increase global sea levels significantly. Some studies have predicted mean sea level increases in the order of six inches to one foot in the next 25 to 50 years. This could have severe irreversible impacts on low-lying areas of Florida's Everglades. The key objective of this study is to evaluate the effects of a one foot sea level rise on Cape Sable Seaside Sparrow (CSSS) nesting areas within the Everglades National Park (ENP). A regional-scale hydrologic model is used to assess the sensitivities of this sea-level rise scenario. Florida's Everglades supports a unique ecosystem. At present, about 50 percent of this unique ecosystem has been lost due to urbanization and farming. Today, the water flow in the remnant Everglades is also regulated to meet a variety of competing environmental, water-supply and flood-control needs. A 30-year, eight billion dollar (1999 estimate) project has been initiated to improve Everglades' water flows. The expected benefits of this restoration project will be short-lived if the predicted sea level rise causes severe impacts on the environmentally sensitive areas of the Everglades. Florida's Everglades is home to many threatened and endangered species of wildlife. The Cape Sable Seaside Sparrow population in the ENP is one such species that is currently listed as endangered. Since these birds build their nests close to the ground surface (the base of the nest is approximately six inches from the ground surface), they are directly affected by any sea level induced ponding depth, frequency or duration change. Therefore, the CSSS population serves as a good indicator species for evaluating the negative impacts of sea level rise on the Everglades' ecosystem. The impact of sea level rise on the CSSS habitat is evaluated using the Regional Simulation Model (RSM) developed by the South Florida Water Management District. The RSM is an implicit, finite-volume, continuous, distributed, and integrated surface-water and ground-water model. It can simulate one-dimensional canal/stream flow and two-dimensional overland and groundwater flow in arbitrarily shaped areas using a variable triangular mesh. The overland and groundwater flow components are fully coupled in the RSM for a more realistic representation of runoff generation.

Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise.

PubMed

Krauss, Ken W; Cormier, Nicole; Osland, Michael J; Kirwan, Matthew L; Stagg, Camille L; Nestlerode, Janet A; Russell, Marc J; From, Andrew S; Spivak, Amanda C; Dantin, Darrin D; Harvey, James E; Almario, Alejandro E

2017-04-21

Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr -1 ), with surface elevation change of 4.2-11.0 mm yr -1 compared with 1.5-7.2 mm yr -1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

Created mangrove wetlands store belowground carbon and surface elevation change enables them to adjust to sea-level rise

USGS Publications Warehouse

Krauss, Ken W.; Cormier, Nicole; Osland, Michael J.; Kirwan, Matthew L.; Stagg, Camille L.; Nestlerode, Janet A.; Russell, Marc J.; From, Andrew; Spivak, Amanda C.; Dantin, Darrin D.; Harvey, James E.; Almario, Alejandro E.

2017-01-01

Mangrove wetlands provide ecosystem services for millions of people, most prominently by providing storm protection, food and fodder. Mangrove wetlands are also valuable ecosystems for promoting carbon (C) sequestration and storage. However, loss of mangrove wetlands and these ecosystem services are a global concern, prompting the restoration and creation of mangrove wetlands as a potential solution. Here, we investigate soil surface elevation change, and its components, in created mangrove wetlands over a 25 year developmental gradient. All created mangrove wetlands were exceeding current relative sea-level rise rates (2.6 mm yr−1), with surface elevation change of 4.2–11.0 mm yr−1 compared with 1.5–7.2 mm yr−1 for nearby reference mangroves. While mangrove wetlands store C persistently in roots/soils, storage capacity is most valuable if maintained with future sea-level rise. Through empirical modeling, we discovered that properly designed creation projects may not only yield enhanced C storage, but also can facilitate wetland persistence perennially under current rates of sea-level rise and, for most sites, for over a century with projected medium accelerations in sea-level rise (IPCC RCP 6.0). Only the fastest projected accelerations in sea-level rise (IPCC RCP 8.5) led to widespread submergence and potential loss of stored C for created mangrove wetlands before 2100.

Constraining Future Sea Level Rise Estimates from the Amundsen Sea Embayment, West Antarctica

NASA Astrophysics Data System (ADS)

Nias, I.; Cornford, S. L.; Edwards, T.; Gourmelen, N.; Payne, A. J.

2016-12-01

The Amundsen Sea Embayment (ASE) is the primary source of mass loss from the West Antarctic Ice Sheet. The catchment is particularly susceptible to grounding line retreat, because the ice sheet is grounded on bedrock that is below sea level and deepening towards its interior. Mass loss from the ASE ice streams, which include Pine Island, Thwaites and Smith glaciers, is a major uncertainty on future sea level rise, and understanding the dynamics of these ice streams is essential to constraining this uncertainty. The aim of this study is to construct a distribution of future ASE sea level contributions from an ensemble of ice sheet model simulations and observations of surface elevation change. A 284 member ensemble was performed using BISICLES, a vertically-integrated ice flow model with adaptive mesh refinement. Within the ensemble parameters associated with basal traction, ice rheology and sub-shelf melt rate were perturbed, and the effect of bed topography and sliding law were also investigated. Initially each configuration was run to 50 model years. Satellite observations of surface height change were then used within a Bayesian framework to assign likelihoods to each ensemble member. Simulations that better reproduced the current thinning patterns across the catchment were given a higher score. The resulting posterior distribution of sea level contributions is narrower than the prior distribution, although the central estimates of sea level rise are similar between the prior and posterior. The most extreme simulations were eliminated and the remaining ensemble members were extended to 200 years, using a simple melt rate forcing.

The burden of prostate cancer in Asian nations

PubMed Central

Cullen, Jennifer; Elsamanoudi, Sally; Brassell, Stephen A.; Chen, Yongmei; Colombo, Monica; Srivastava, Amita; McLeod, David G.

2012-01-01

Introduction: In this review, the International Agency for Research on Cancer's cancer epidemiology databases were used to examine prostate cancer (PCa) age-standardized incidence rates (ASIR) in selected Asian nations, including Cancer Incidence in Five Continents (CI5) and GLOBOCAN databases, in an effort to determine whether ASIRs are rising in regions of the world with historically low risk of PCa development. Materials and Methods: Asian nations with adequate data quality were considered for this review. PCa ASIR estimates from CI5 and GLOBOCAN 2008 public use databases were examined in the four eligible countries: China, Japan, Korea and Singapore. Time trends in PCa ASIRs were examined using CI5 Volumes I-IX. Results: While PCa ASIRs remain much lower in the Asian nations examined than in North America, there is a clear trend of increasing PCa ASIRs in the four countries examined. Conclusion: Efforts to systematically collect cancer incidence data in Asian nations must be expanded. Current CI5 data indicate a rise in PCa ASIR in several populous Asian countries. If these rates continue to rise, it is uncertain whether there will be sufficient resources in place, in terms of trained personnel and infrastructure for medical treatment and continuum of care, to handle the increase in PCa patient volume. The recommendation by some experts to initiate PSA screening in Asian nations could compound a resource shortfall. Obtaining accurate estimates of PCa incidence in these countries is critically important for preparing for a potential shift in the public health burden posed by this disease. PMID:22529743

Identification of cells initiating human melanomas.

PubMed

Schatton, Tobias; Murphy, George F; Frank, Natasha Y; Yamaura, Kazuhiro; Waaga-Gasser, Ana Maria; Gasser, Martin; Zhan, Qian; Jordan, Stefan; Duncan, Lyn M; Weishaupt, Carsten; Fuhlbrigge, Robert C; Kupper, Thomas S; Sayegh, Mohamed H; Frank, Markus H

2008-01-17

Tumour-initiating cells capable of self-renewal and differentiation, which are responsible for tumour growth, have been identified in human haematological malignancies and solid cancers. If such minority populations are associated with tumour progression in human patients, specific targeting of tumour-initiating cells could be a strategy to eradicate cancers currently resistant to systemic therapy. Here we identify a subpopulation enriched for human malignant-melanoma-initiating cells (MMIC) defined by expression of the chemoresistance mediator ABCB5 (refs 7, 8) and show that specific targeting of this tumorigenic minority population inhibits tumour growth. ABCB5+ tumour cells detected in human melanoma patients show a primitive molecular phenotype and correlate with clinical melanoma progression. In serial human-to-mouse xenotransplantation experiments, ABCB5+ melanoma cells possess greater tumorigenic capacity than ABCB5- bulk populations and re-establish clinical tumour heterogeneity. In vivo genetic lineage tracking demonstrates a specific capacity of ABCB5+ subpopulations for self-renewal and differentiation, because ABCB5+ cancer cells generate both ABCB5+ and ABCB5- progeny, whereas ABCB5- tumour populations give rise, at lower rates, exclusively to ABCB5- cells. In an initial proof-of-principle analysis, designed to test the hypothesis that MMIC are also required for growth of established tumours, systemic administration of a monoclonal antibody directed at ABCB5, shown to be capable of inducing antibody-dependent cell-mediated cytotoxicity in ABCB5+ MMIC, exerted tumour-inhibitory effects. Identification of tumour-initiating cells with enhanced abundance in more advanced disease but susceptibility to specific targeting through a defining chemoresistance determinant has important implications for cancer therapy.

High field superconductors for superconducting machines

NASA Astrophysics Data System (ADS)

Rupp, G.; Wilhelm, M.; Wohlleben, K.; Ziegler, G.; Springer, E.

1980-11-01

High current capacity Nb3Sn multifilament conductors were fabricated. A solid state diffusion process was used. The number of conductor filaments approaches 70,000 with filament diameters being approximately 1.5 microns. Effective current densities reach 86,000 A/sq cm at a magnetic flux density of 10 T and operating temperature of 4.2 K. Calibrated flattened cables of twisted strands were fabricated for higher currents (up to 1000 A at 10 T). Generally, quantitative relations can be given for the rise in the critical current of Nb3Sn multifilament conductors, observed under the influence of mechanical stresses. Long lengths (km) of these conductors were used to manufacture superconducting solenoids two different ways. These rise to the short sample current, usually without conditioning, and deliver magnetic flux densities up to 14 T with an 8.5 T NbTi background field.

Zinc electrodeposition from flowing alkaline zincate solutions: Role of hydrogen evolution reaction

NASA Astrophysics Data System (ADS)

Dundálek, Jan; Šnajdr, Ivo; Libánský, Ondřej; Vrána, Jiří; Pocedič, Jaromír; Mazúr, Petr; Kosek, Juraj

2017-12-01

The hydrogen evolution reaction is known as a parasitic reaction during the zinc electrodeposition from alkaline zincate solutions and is thus responsible for current efficiency losses during the electrolysis. Besides that, the rising hydrogen bubbles may cause an extra convection within a diffusion layer, which leads to an enhanced mass transport of zincate ions to an electrode surface. In this work, the mentioned phenomena were studied experimentally in a flow through electrolyzer and the obtained data were subsequently evaluated by mathematical models. The results prove the indisputable influence of the rising hydrogen bubbles on the additional mixing of the diffusion layer, which partially compensates the drop of the current efficiency of the zinc deposition at higher current flows. Moreover, the results show that the current density ratio (i.e., the ratio of an overall current density to a zinc limiting current density) is not suitable for the description of the zinc deposition, because the hydrogen evolution current density is always involved in the overall current density.

Spectroscopic Measurements of Planar Foil Plasmas Driven by a MA LTD

NASA Astrophysics Data System (ADS)

Patel, Sonal; Yager-Elorriaga, David; Steiner, Adam; Jordan, Nick; Gilgenbach, Ronald; Lau, Y. Y.

2014-10-01

Planar foil ablation experiments are being conducted on the Linear Transformer Driver (LTD) at the University of Michigan. The experiment consists of a 400 nm-thick, Al planar foil and a current return post. An optical fiber is placed perpendicular to the magnetic field and linear polarizers are used to isolate the pi and sigma lines. The LTD is charged to +/-70 kV with approximately 400-500 kA passing through the foil. Laser shadowgraphy has previously imaged the plasma and measured anisotropy in the Magneto Rayleigh-Taylor (MRT) instability. Localized magnetic field measurements using Zeeman splitting during the current rise is expected to yield some insight into this anisotropy. Initial experiments use Na D lines of Al foils seeded with sodium to measure Zeeman splitting. Several ion lines are also currently being studied, such as Al III and C IV, to probe the higher temperature core plasma. In planned experiments, several lens-coupled optical fibers will be placed across the foil, and local magnetic field measurements will be taken to measure current division within the plasma. This work was supported by US DoE. S.G. Patel and A.M. Steiner supported by NPSC funded by Sandia. D.A. Yager supported by NSF fellowship Grant DGE 1256260.

REDUCING AMBIGUITY IN THE FUNCTIONAL ASSESSMENT OF PROBLEM BEHAVIOR

PubMed Central

Rooker, Griffin W.; DeLeon, Iser G.; Borrero, Carrie S. W.; Frank-Crawford, Michelle A.; Roscoe, Eileen M.

2015-01-01

Severe problem behavior (e.g., self-injury and aggression) remains among the most serious challenges for the habilitation of persons with intellectual disabilities and is a significant obstacle to community integration. The current standard of behavior analytic treatment for problem behavior in this population consists of a functional assessment and treatment model. Within that model, the first step is to assess the behavior–environment relations that give rise to and maintain problem behavior, a functional behavioral assessment. Conventional methods of assessing behavioral function include indirect, descriptive, and experimental assessments of problem behavior. Clinical investigators have produced a rich literature demonstrating the relative effectiveness for each method, but in clinical practice, each can produce ambiguous or difficult-to-interpret outcomes that may impede treatment development. This paper outlines potential sources of variability in assessment outcomes and then reviews the evidence on strategies for avoiding ambiguous outcomes and/or clarifying initially ambiguous results. The end result for each assessment method is a set of best practice guidelines, given the available evidence, for conducting the initial assessment. PMID:26236145

Activity-Dependent Gating of Calcium Spikes by A-type K+ Channels Controls Climbing Fiber Signaling in Purkinje Cell Dendrites

PubMed Central

Otsu, Yo; Marcaggi, Païkan; Feltz, Anne; Isope, Philippe; Kollo, Mihaly; Nusser, Zoltan; Mathieu, Benjamin; Kano, Masanobu; Tsujita, Mika; Sakimura, Kenji; Dieudonné, Stéphane

2014-01-01

Summary In cerebellar Purkinje cell dendrites, heterosynaptic calcium signaling induced by the proximal climbing fiber (CF) input controls plasticity at distal parallel fiber (PF) synapses. The substrate and regulation of this long-range dendritic calcium signaling are poorly understood. Using high-speed calcium imaging, we examine the role of active dendritic conductances. Under basal conditions, CF stimulation evokes T-type calcium signaling displaying sharp proximodistal decrement. Combined mGluR1 receptor activation and depolarization, two activity-dependent signals, unlock P/Q calcium spikes initiation and propagation, mediating efficient CF signaling at distal sites. These spikes are initiated in proximal smooth dendrites, independently from somatic sodium action potentials, and evoke high-frequency bursts of all-or-none fast-rising calcium transients in PF spines. Gradual calcium spike burst unlocking arises from increasing inactivation of mGluR1-modulated low-threshold A-type potassium channels located in distal dendrites. Evidence for graded activity-dependent CF calcium signaling at PF synapses refines current views on cerebellar supervised learning rules. PMID:25220810

Back to the future? Views of heads of schools of nursing about undergraduate specialization in mental health nursing.

PubMed

Happell, Brenda; McAllister, Margaret

2014-12-01

Preparation of nursing students for practice in mental health settings in Australia has been criticized since comprehensive education replaced preregistration specialist education. Current and projected workforce shortages have given rise to considering the reintroduction of specialization at preregistration level as a potential solution. Support of heads of schools of nursing would be essential for such an initiative to be considered. A qualitative exploratory study was undertaken involving in-depth telephone interviews with heads of schools of nursing in Queensland. Participants generally favoured the concept of specialization in mental health nursing at undergraduate level. Data analysis revealed the following themes: meeting workforce needs, improving quality of care, employability of graduates, an attractive option for students, and what would have to go. Participants identified many benefits to mental health service delivery and consumer outcomes. How the initiative could be developed within an already overcrowded curriculum was identified as the major barrier. This level of support is encouraging if necessary changes to the educational preparation for mental health nursing practice are to be considered. © 2014 Australian College of Mental Health Nurses Inc.

Using Hybrid Change Strategies to Improve the Patient Experience in Outpatient Specialty Care.

PubMed

Miranda, Rafael; Glenn, Sean W; Leighton, Jonathan A; Pasha, Shabana E; Gurudu, Suryakanth R; Teaford, Harry G; Mertz, Lester E; Lee, Howard R; Mamby, Sylvia A; Johnson, Margaret F; Raghu, T S

2015-01-01

The emerging changes in healthcare impose significant burdens on integrated outpatient specialty services with respect to setting patient expectations, handling outside medical records; and coordinating specialty appointments scheduling. Moreover, because of the evolution of the electronic health record and its widespread use, it is critical that patient and physician interaction is maintained and clerical tasks are minimized. In the context of increased government regulation, declining reimbursement, and the rise of new payment models, outpatient practices need to be reimagined so that they are more efficient for the patient and the provider. The redesign of integrated outpatient specialty services can be accomplished only through teamwork, innovation, and efficient use of technology. To address these challenges, the Department of Medicine at Mayo Clinic in Scottsdale, Arizona, implemented an ideal practice design initiative that leveraged a hybrid set of change strategies. The change strategy, which was initiated after examination of current practices and design options, engaged key stakeholders and patients. A number of enablers and barriers to adoption were identified as a result of the implementation experience.

Analysis of Radiation Effects in Silicon using Kinetic Monte Carlo Methods

DOE PAGES

Hehr, Brian Douglas

2014-11-25

The transient degradation of semiconductor device performance under irradiation has long been an issue of concern. Neutron irradiation can instigate the formation of quasi-stable defect structures, thereby introducing new energy levels into the bandgap that alter carrier lifetimes and give rise to such phenomena as gain degradation in bipolar junction transistors. Normally, the initial defect formation phase is followed by a recovery phase in which defect-defect or defect-dopant interactions modify the characteristics of the damaged structure. A kinetic Monte Carlo (KMC) code has been developed to model both thermal and carrier injection annealing of initial defect structures in semiconductor materials.more » The code is employed to investigate annealing in electron-irradiated, p-type silicon as well as the recovery of base current in silicon transistors bombarded with neutrons at the Los Alamos Neutron Science Center (LANSCE) “Blue Room” facility. Our results reveal that KMC calculations agree well with these experiments once adjustments are made, within the appropriate uncertainty bounds, to some of the sensitive defect parameters.« less

Kurtosis, skewness, and non-Gaussian cosmological density perturbations

NASA Technical Reports Server (NTRS)

Luo, Xiaochun; Schramm, David N.

1993-01-01

Cosmological topological defects as well as some nonstandard inflation models can give rise to non-Gaussian density perturbations. Skewness and kurtosis are the third and fourth moments that measure the deviation of a distribution from a Gaussian. Measurement of these moments for the cosmological density field and for the microwave background temperature anisotropy can provide a test of the Gaussian nature of the primordial fluctuation spectrum. In the case of the density field, the importance of measuring the kurtosis is stressed since it will be preserved through the weakly nonlinear gravitational evolution epoch. Current constraints on skewness and kurtosis of primeval perturbations are obtained from the observed density contrast on small scales and from recent COBE observations of temperature anisotropies on large scales. It is also shown how, in principle, future microwave anisotropy experiments might be able to reveal the initial skewness and kurtosis. It is shown that present data argue that if the initial spectrum is adiabatic, then it is probably Gaussian, but non-Gaussian isocurvature fluctuations are still allowed, and these are what topological defects provide.

Activity-dependent gating of calcium spikes by A-type K+ channels controls climbing fiber signaling in Purkinje cell dendrites.

PubMed

Otsu, Yo; Marcaggi, Païkan; Feltz, Anne; Isope, Philippe; Kollo, Mihaly; Nusser, Zoltan; Mathieu, Benjamin; Kano, Masanobu; Tsujita, Mika; Sakimura, Kenji; Dieudonné, Stéphane

2014-10-01

In cerebellar Purkinje cell dendrites, heterosynaptic calcium signaling induced by the proximal climbing fiber (CF) input controls plasticity at distal parallel fiber (PF) synapses. The substrate and regulation of this long-range dendritic calcium signaling are poorly understood. Using high-speed calcium imaging, we examine the role of active dendritic conductances. Under basal conditions, CF stimulation evokes T-type calcium signaling displaying sharp proximodistal decrement. Combined mGluR1 receptor activation and depolarization, two activity-dependent signals, unlock P/Q calcium spikes initiation and propagation, mediating efficient CF signaling at distal sites. These spikes are initiated in proximal smooth dendrites, independently from somatic sodium action potentials, and evoke high-frequency bursts of all-or-none fast-rising calcium transients in PF spines. Gradual calcium spike burst unlocking arises from increasing inactivation of mGluR1-modulated low-threshold A-type potassium channels located in distal dendrites. Evidence for graded activity-dependent CF calcium signaling at PF synapses refines current views on cerebellar supervised learning rules. Copyright © 2014 Elsevier Inc. All rights reserved.

Sources and sinks of Earth's ring current populations

NASA Astrophysics Data System (ADS)

Mauk, B.

2017-12-01

Processes that modify and transport current-carrying particles into and out of Earth's ring current regions are overviewed and discussed here with a focus on outstanding mysteries and uncertainties. Examples of such mysteries include the following. Some modeling and observational approaches point to a need for storm-time enhancements in the global electric field configuration to help bring magnetotail populations into the inner magnetosphere. And yet, electric field measurements from several missions, most recently the Van Allen Probes, suggest that only highly transient enhancements occur in critical regions that connect the outer and inner regions. Global enhancements appear to be internally generated rather than necessarily being driven from the outside. Another sample mystery involves the processes that give rise to the sometimes initial prompt recovery of the magnetic storm indice DST, given that loss processes traditionally invoked are likely too slow. Wave losses, such as those engendered by Electromagnetic Ion Cyclotron (EMIC) waves, may be responsible, but observational support for such a solution is lacking. These and other uncertainties are discussed with a goal of addressing how they might be addressed with the present great constellation of Earth-orbiting spacecraft, most recently joined by MMS and Arase (ERG).

A No-Arc DC Circuit Breaker Based on Zero-Current Interruption

NASA Astrophysics Data System (ADS)

Xiang, Xuewei; Chai, Jianyun; Sun, Xudong

2017-05-01

A dc system has no natural current zero-crossing point, so a dc arc is more difficult to extinguish than an ac arc. In order to effectively solve the problem of the dc arc, this paper proposes a dc circuit breaker (DCCB) capable of implementing a no-arc interruption. The proposed DCCB includes a main branch consisting of a mechanical switch, a diode and a current-limiting inductor, a semi-period resonance circuit consisting of a diode, an inductor and a capacitor, and a buffer branch consisting of a capacitor, a thyristor and a resistor. The mechanical switch is opened in a zero-current state, and the overvoltage caused by the counter electromotive force of the inductor does not exist. Meanwhile, the capacitor has a buffering effect on the voltage. The rising of the voltage of the mechanical switch is slower than the rising of the insulating strength of a contact gap of the mechanical switch, resulting in the contact gap not able to be broken down. Thus, the arc cannot be generated. The simulation results show that the proposed DCCB does not generate the arc in the interruption process, the rise rate of the short circuit current can be effectively limited, and the short circuit fault point can be rapidly isolated from the dc power supply.

Inclined gravity currents filling basins: The influence of Reynolds number on entrainment into gravity currents

NASA Astrophysics Data System (ADS)

Hogg, Charlie A. R.; Dalziel, Stuart B.; Huppert, Herbert E.; Imberger, Jörg

2015-09-01

In many important natural and industrial systems, gravity currents of dense fluid feed basins. Examples include lakes fed by dense rivers and auditoria supplied with cooled air by ventilation systems. As we will show, the entrainment into such buoyancy driven currents can be influenced by viscous forces. Little work, however, has examined this viscous influence and how entrainment varies with the Reynolds number, Re. Using the idea of an entrainment coefficient, E, we derive a mathematical expression for the rise of the front at the top of the dense fluid ponding in a basin, where the horizontal cross-sectional area of the basin varies linearly with depth. We compare this expression to experiments on gravity currents with source Reynolds numbers, Res, covering the broad range 100 < Res < 1500. The form of the observed frontal rises was well approximated by our theory. By fitting the observed frontal rises to the theoretical form with E as the free parameter, we find a linear trend for E(Res) over the range 350 < Res < 1100, which is in the transition to turbulent flow. In the experiments, the entrainment coefficient, E, varied from 4 × 10-5 to 7 × 10-2. These observations show that viscous damping can be a dominant influence on gravity current entrainment in the laboratory and in geophysical flows in this transitional regime.

Linking research to practice: the rise of evidence-based health sciences librarianship*

PubMed Central

Marshall, Joanne Gard

2014-01-01

Purpose: The lecture explores the origins of evidence-based practice (EBP) in health sciences librarianship beginning with examples from the work of Janet Doe and past Doe lecturers. Additional sources of evidence are used to document the rise of research and EBP as integral components of our professional work. Methods: Four sources of evidence are used to examine the rise of EBP: (1) a publication by Doe and research-related content in past Doe lectures, (2) research-related word usage in articles in the Bulletin of the Medical Library Association and Journal of the Medical Library Association between 1961 and 2010, (3) Medical Library Association activities, and (4) EBP as an international movement. Results: These sources of evidence confirm the rise of EBP in health sciences librarianship. International initiatives sparked the rise of evidence-based librarianship and continue to characterize the movement. This review shows the emergence of a unique form of EBP that, although inspired by evidence-based medicine (EBM), has developed its own view of evidence and its application in library and information practice. Implications: Health sciences librarians have played a key role in initiating, nurturing, and spreading EBP in other branches of our profession. Our close association with EBM set the stage for developing our own EBP. While we relied on EBM as a model for our early efforts, we can observe the continuing evolution of our own unique approach to using, creating, and applying evidence from a variety of sources to improve the quality of health information services. PMID:24415915

Diversifying Science: Intervention Programs Moderate the Effect of Stereotype Threat on Motivation and Career Choice

PubMed Central

Woodcock, Anna; Hernandez, Paul R.; Schultz, P. Wesley

2016-01-01

Stereotypes influence academic interests, performance, and ultimately career goals. The long-standing National Institutes of Health Research Initiative for Scientific Enhancement (RISE) training program has been shown to be effective at retaining underrepresented minorities in science. We argue that programs such as RISE may alter the experience and impact of stereotype threat on academic achievement goals and future engagement in a scientific career. We report analyses of a national sample comparing RISE students with a propensity score-matched control group over a 6-year period. Mediation analyses revealed that while RISE program membership did not buffer students from stereotype threat, it changed students' downstream responses and ultimately their academic outcomes. Nonprogram students were less likely than RISE students to persist in the sciences, partially because feelings of stereotype threat diminished their adoption of mastery goals. We discuss how these findings inform stereotype threat and goal orientation theories and provide insight into the success of intervention programs. PMID:27668075

Economic efficiency of high-rise construction in the Moscow program of renovation of housing stock

NASA Astrophysics Data System (ADS)

Misailovov, Andrey

2018-03-01

The article considers a new initiative of the regional authorities of updating the housing stock designated as the renovation of housing. Its main aspects are analyzed, including the nature of program, economic efficiency of its implementation due to high-rise construction and the regulatory and legislative framework, the procedure for implementing the program, and the time frame for its implementation. The role of the program for regions in which high depreciation of the housing stock is combined with a limited number of sites for a new housing construction is disclosed. The high-rise construction in the renovation program is presented as a variant of a successful solution not only of the tasks of renovating the housing stock, but also of filling the regional budget. The social and economic orientation of the high-rise construction and the involvement of residents in the process of making town-planning decisions in the field of high-rise construction at all stages of implementing the program are shown.

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.

Local Climate Zones Classification to Urban Planning in the Mega City of São Paulo - SP, Brazil

NASA Astrophysics Data System (ADS)

Gonçalves Santos, Rafael; Saraiva Lopes, António Manuel; Prata-Shimomura, Alessandra

2017-04-01

Local Climate Zones Classification to Urban Planning in the Mega city of São Paulo - SP, Brazil Tropical megacities have presented a strong trend in growing urban. Urban management in megacities has as one of the biggest challenges is the lack of integration of urban climate and urban planning to promote ecologically smart cities. Local Climatic Zones (LCZs) are considered as important and recognized tool for urban climate management. Classes are local in scale, climatic in nature, and zonal in representation. They can be understood as regions of uniform surface cover, structure, material and human activity that have to a unique climate response. As an initial tool to promote urban climate planning, LCZs represent a simple composition of different land coverages (buildings, vegetation, soils, rock, roads and water). LCZs are divided in 17 classes, they are based on surface cover (built fraction, soil moisture, albedo), surface structure (sky view factor, roughness height) and cultural activity (anthropogenic heat flux). The aim of this study is the application of the LCZs classification system in the megacity of São Paulo, Brazil. Located at a latitude of 23° 21' and longitude 46° 44' near to the Tropic of Capricorn, presenting humid subtropical climate (Cfa) with diversified topographies. The megacity of São Paulo currently concentrates 11.890.000 inhabitants is characterized by large urban conglomerates with impermeable surfaces and high verticalization, having as result high urban heat island intensity. The result indicates predominance in urban zones of Compact low-rise, Compact Mid-rise, Compact High-rise and Open Low-rise. Non-urban regions are mainly covered by dense vegetation and water. The LCZs classification system promotes significant advantages for climate sensitive urban planning in the megacity of São Paulo. They offers new perspectives to the management of temperature and urban ventilation and allows the formulation of urban planning guidelines and climatic. Key words: Local Climatic Zones; Urban Panning; Megacities; São Paulo.

Initial aging phenomena in copper-chromium alloys

NASA Technical Reports Server (NTRS)

Suzuki, H.; Motohiro, K.

1985-01-01

The effects of quenching and aging temperatures on the initial aging curves of Cu-Cr alloy were examined mainly by means of electrical resistivity measurements. Three Cu-Cr alloy specimens having 0.24, 0.74, and 1.0% Cr were solution-treated at 950-1050 C, quenched into ice-water, and subsequently aged at 300-500 C. The results were as follows: (1) At the very early stage of aging (within about 30 sec), an abrupt decrease of resistivity with lowering aging tempratures. (T sub A) and rising solution temperatures (T sub S) was observed at (T sub A) up to about 400 C. In contrast, a transient increase of resistivity with rising T sub A and lowering T sub S was observed at T sub A from about 450 to 500 C. These phenomena seem to be caused by a rapid formation of solute clusters and the reversion of clusters formed during quenching, which are enhanced by quenched-in vacancies, respectively. (2) The amount of precipitation increased at the latter stage of aging with rising T sub S and T sub A as generally expected, where T sub S was not so high as to form secondary defects. (3) As a result, the initial aging phenomena in Cr-Cr alloy were revealed to be complicated against expectations. This was considered to be due to the migration energy of vacancies so larger in Cu-base.

Breast-feeding and Vitamin D Supplementation Rates in the Ochsner Health System

PubMed Central

Ponnapakkam, Tulasi; Ravichandran, Anisha; Bradford, Elease; Tobin, Gregory; Gensure, Robert

2008-01-01

Breast-feeding imparts many benefits to both mothers and infants. Because of these numerous recognized benefits, there has been an effort to increase breast-feeding rates nationwide; increasing breast-feeding rates was one of the goals of the U.S. Department of Health and Human Services' Healthy People 2010 initiative. This study examined the breast-feeding rate at the Ochsner Clinic Foundation by conducting a retrospective chart review of patients aged 0–12 months who visited any branch of the Ochsner hospital system. Our results indicate that the rate of initiation of breast-feeding for children followed at the Ochsner Clinic Foundation is 66.3%. However, as breast-feeding rates rise, there is concern that there may be a resurgence of rickets, a disease caused by the deficiency of vitamin D. Currently the American Academy of Pediatrics recommends that exclusively breast-fed infants receive vitamin D supplementation starting within the first 2 months of life. We have therefore initiated a clinical trial to determine whether vitamin D supplementation is required to prevent rickets in breast-fed children. In the course of conducting this study, we have gathered additional data regarding the patterns of breast-feeding and of vitamin D supplementation for babies born at Ochsner. PMID:21603467

An 'end-game' for sugar sweetened beverages?

PubMed

Sundborn, G; Merriman, T R; Thornley, S; Metcalf, P; Jackson, R

2014-03-01

The epidemic of unhealthy weight is now in its third decade. The multitude of initiatives designed to address this issue (globally) have predominantly been ineffective as the prevalence of unhealthy weight has continued to rise. Public health professionals have proposed an 'endgame' for tobacco smoking in New Zealand by 2025, which has received widespread support. Similarly, here, to control the prevalence of unhealthy weight, we consider whether a similar approach to tobacco is justified to restrict the intake of sweetened beverages. This paper reviews the evidence relating sugar sweetened beverages to unhealthy weight and adverse health effects. Current initiatives aimed at reducing sugar sweetened beverage consumption both internationally and in New Zealand are reviewed. Epidemiological evidence consistently links sugar-sweetened drink intake with unhealthy weight and other risk factors for cardiovascular disease, such as diabetes, gout, and raised blood pressure. Food disappearance data suggests that sugar intake continues to increase in New Zealand, and that a subtle addiction to sugar may underlie this trend. A number of successful initiatives to reduce sugary drink intake are described. IMPLICATION/CONCLUSION: We argue that an 'endgame' to the consumption of sugar-sweetened beverages be supported as a means to address the issue of unhealthy weight at a population level. Finally, a preliminary draft endgame plan is presented for consideration, dialogue and debate.

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.

Breast-feeding and Vitamin D Supplementation Rates in the Ochsner Health System.

PubMed

Ponnapakkam, Tulasi; Ravichandran, Anisha; Bradford, Elease; Tobin, Gregory; Gensure, Robert

2008-01-01

Breast-feeding imparts many benefits to both mothers and infants. Because of these numerous recognized benefits, there has been an effort to increase breast-feeding rates nationwide; increasing breast-feeding rates was one of the goals of the U.S. Department of Health and Human Services' Healthy People 2010 initiative. This study examined the breast-feeding rate at the Ochsner Clinic Foundation by conducting a retrospective chart review of patients aged 0-12 months who visited any branch of the Ochsner hospital system. Our results indicate that the rate of initiation of breast-feeding for children followed at the Ochsner Clinic Foundation is 66.3%. However, as breast-feeding rates rise, there is concern that there may be a resurgence of rickets, a disease caused by the deficiency of vitamin D. Currently the American Academy of Pediatrics recommends that exclusively breast-fed infants receive vitamin D supplementation starting within the first 2 months of life. We have therefore initiated a clinical trial to determine whether vitamin D supplementation is required to prevent rickets in breast-fed children. In the course of conducting this study, we have gathered additional data regarding the patterns of breast-feeding and of vitamin D supplementation for babies born at Ochsner.

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.

Current Research Activities of the Department of Oceanography.

DTIC Science & Technology

1981-04-01

being analyzed in terms of the structure of the East Pacific A multi-institutional investi- Rise at 12* N and the change in crus- gation on the abundance...seismic experiment at the axis of the East Pacific Rise . Marine Geology 35: 147-169. No. 1090 McDaniel, N . and K. Banse (1979) A novel method of...proceeded eastward from Tahiti ducted off the Oregon and Washington to the East Pacific Rise area, then coasts. In late August a return back to Tahiti. On

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.

ECH-assisted startup at KSTAR

NASA Astrophysics Data System (ADS)

Bae, Y. S.; Jeong, J. H.; Park, S. I.; Cho, M. H.; Namkung, W.; Jackson, G. L.; Joung, M.; Yoon, S. W.; Kim, J. H.; Hahn, S. H.; Kim, W. C.; Yang, H. L.; Oh, Y. K.; Humphreys, D.; Walker, M. L.; Gorelov, Y.; Leuer, J. A.; Hyatt, A. W.; Eidietis, N. W.; Mueller, D.; Bak, J. S.; Kwon, M.

2009-11-01

The electron cyclotron heating (ECH)-assisted startup was successful in the Korea Superconducting Tokamak Advanced Research (KSTAR) first plasma campaign completed in June, 2008. It was observed that the second harmonic EC wave of 0.35 MW was sufficient to achieve breakdown in the ECH pre-ionization phase, to allow burn through, and to sustain the plasma during the current ramp with a low loop voltage of 2.0 V. This corresponds to a toroidal electric field of 0.24 Vm-1 at the innermost vacuum vessel wall (R = 1.3 m). Since there is no feedback control of the plasma radial position in the initial phase of the KSTAR first plasma campaign, wall contact caused the plasma current fall to zero soon after the ECH beam was turned off. Extending pulse duration of the ECH power to 190 ms allowed the plasma current to rise up to more than 100 kA with a ramp-up rate of 0.8 MA/s and the pulse duration of 210 ms. Later in the first plasma campaign, the plasma was sustained up to 865 ms with the help of additional heating of 350-ms long ECH beam and with the help of the plasma radial position feedback control. The plasma current in the pre-ionization phase was observed and it is considered to be pressure-driven Pfirsch-Schlüter current.

Initial Training and Labour-Market Entry among French Youth.

ERIC Educational Resources Information Center

Training & Employment: French Dimensions, 1991

1991-01-01

Over the past 15 years, the level of initial training among French youth has shown a rapid rise, with one of the highest rates of full-time school attendance in Europe. This sharp increase in school attendance clearly improves the training capital. In their hiring policies, employers have become more and more selective, with the result that…

Magnetic hyperthermia in water based ferrofluids: Effects of initial susceptibility and size polydispersity on heating efficiency

NASA Astrophysics Data System (ADS)

Lahiri, B. B.; Ranoo, Surojit; Muthukumaran, T.; Philip, John

2018-04-01

The effects of initial susceptibility and size polydispersity on magnetic hyperthermia efficiency in two water based ferrofluids containing phosphate and TMAOH coated superparamagnetic Fe3O4 nanoparticles were studied. Experiments were performed at a fixed frequency of 126 kHz on four different concentrations of both samples and under different external field amplitudes. It was observed that for field amplitudes beyond 45.0 kAm-1, the maximum temperature rise was in the vicinity of 42°C (hyperthermia limit) which indicated the suitability of the water based ferrofluids for hyperthermia applications. The maximum temperature rise and specific absorption rate were found to vary linearly with square of the applied field amplitudes, in accordance with theoretical predictions. It was further observed that for a fixed sample concentration, specific absorption rate was higher for the phosphate coated samples which was attributed to the higher initial static susceptibility and lower size polydispersity of phosphate coated Fe3O4.

The initial freezing point temperature of beef rises with the rise in pH: a short communication.

PubMed

Farouk, M M; Kemp, R M; Cartwright, S; North, M

2013-05-01

This study tested the hypothesis that the initial freezing point temperature of meat is affected by pH. Sixty four bovine M. longissimus thoracis et lumborum were classified into two ultimate pH groups: low (<5.8) and high pH (>6.2) and their cooling and freezing point temperatures were determined. The initial freezing temperatures for beef ranged from -0.9 to -1.5°C (∆=0.6°C) with the higher and lower temperatures associated with high and low ultimate pH respectively. There was a significant correlation (r=+0.73, P<0.01) between beef pH and freezing point temperature in the present study. The outcome of this study has implications for the meat industry where evidence of freezing (ice formation) in a shipment as a result of high pH meat could result in a container load of valuable chilled product being downgraded to a lower value frozen product. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Power-control switch

NASA Technical Reports Server (NTRS)

Kessler, L. L.

1976-01-01

Constant-current source creates drive current independent of input-voltage variations, 50% reduction in power loss in base drive circuitry, maintains essentially constant charge rate, and improves rise-time consistency over input voltage range.

Model 'zero-age' lunar thermal profiles resulting from electrical induction

NASA Technical Reports Server (NTRS)

Herbert, F.; Sonett, C. P.; Wiskerchen, M. J.

1977-01-01

Thermal profiles for the moon are calculated under the assumption that a pre-main-sequence T-Tauri-like solar wind excites both transverse magnetic and transverse electric induction while the moon is accreting. A substantial initial temperature rise occurs, possibly of sufficient magnitude to cause subsequent early extensive melting throughout the moon in conjunction with nominal long-lived radioactives. In these models, accretion is an unimportant direct source of thermal energy but is important because even small temperature rises from accretion cause significant changes in bulk electrical conductivity. Induction depends upon the radius of the moon, which we take to be accumulating while it is being heated electrically. The 'zero-age' profiles calculated in this paper are proposed as initial conditions for long-term thermal evolution of the moon.

Hyper-G stress-induced hyperglycemia in rats mediated by glucoregulatory hormones

NASA Technical Reports Server (NTRS)

Daligcon, B. C.; Oyama, J.

1985-01-01

The present investigation is concerned with possible relations of the hyperglycemic response of rats exposed to hyper-G stress to (1) alterations in blood levels of the glucoregulatory hormones and gluconeogenic substrates, and (2) changes in insulin response on muscle glucose uptake. Male Sprague-Dawley rats weighing 250-300 g were used in the study. The results of the experiments indicate that the initial rapid rise in blood glucose of rats exposed to hyper-G stress is mediated by increases in circulating catecholamines and glucagon, both potent stimulators of hepatic gluconeogenesis. Lactate, derived from epinephrine stimulation of muscle glycogenolysis, appears to be a major precursor for the initial rise in blood glucose. The inhibition of the insulin-stimulated glucose uptake by muscle tissues may be a factor in the observed sustained hyperglycemia.

The effect of laser process parameters on microstructure and dilution rate of cladding coatings

NASA Astrophysics Data System (ADS)

Bin, Liu; Heping, Liu; Xingbin, Jing; Yuxin, Li; Peikang, Bai

2018-02-01

In order to broaden the range of application of Q235 steel, it is necessary to repair the surface of steel. High performance 316L stainless steel coating was successfully obtained on Q235 steel by laser cladding technology. The effect of laser cladding parameters on the geometrical size and appearance of single cladding layer was investigated. The experimental results show that laser current has an important influence on the surface morphology of single channel cladding. When the current is from 155A to 165A, the cladding coating becomes smooth. The laser current has an effect on the geometric cross section size and dilution rate of single cladding. The results revealed that with the rising of laser current, the width, height and depth of layer increase gradually. With the rising of laser current, the dilution rate of cladding layer is gradually increasing.

Exploring a Resource Dependency Perspective as an Organizational Strategy for Building Resource Capacity

ERIC Educational Resources Information Center

Powell, Kimberly K.; Rey, Melanie Powell

2015-01-01

Declining state revenue, increased expenditures and rising costs at public universities are critical issues that are further heightened by the current economic environment. In an effort to address the challenges associated with reduced revenue and rising costs, this theoretical paper will explore how public institutions can leverage the resource…

The Problem of Defensive Medicine

ERIC Educational Resources Information Center

Barondess, Jeremiah A.; Tancredi, Laurence R.

1978-01-01

Defensive medicine (the use of diagnostic and end-treatment measures explicitly for the purposes of averting malpractice suits) is frequently cited as one of the least desirable effects of the current rise in medical litigation. It is claimed that defensive medicine is responsible for the rising cost of health care and the exposure of patients to…

Initiation of the Slow-Rise and Fast-Rise Phases of an Erupting Solar Filament by Localized Emerging Magnetic Field via Microflaring

NASA Technical Reports Server (NTRS)

Sterling, A. C.; Moore, R. L.; Harra, L. K.

2006-01-01

EUV data from EIT show that a filament of 2001 February 28 underwent a slow-rise phase lasting about 6 hrs, before rapidly erupting in a fast-rise phase. Concurrent images in soft X-rays (SXRs) from Yohkoh/SXT show that a series of three microflares, prominent in SXT images but weak in EIT approx.195 Ang EUV images, occurred near one end of the filament. The first and last microflares occurred respectively in conjunction with the start of the slow-rise phase and the start of the fast-rise phase, and the second microflare corresponded to a kink in the filament trajectory. Beginning within 10 hours of the start of the slow rise, new magnetic flux emerged at the location of the microflaring. This localized new flux emergence and the resulting microflares, consistent with reconnection between the emerging field and the sheared sigmoid core magnetic field holding the filament, apparently caused the slow rise of this field and the transition to explosive eruption. For the first time in such detail, the observations show this direct action of localized emerging flux in the progressive destabilization of a sheared core field in the onset of a coronal mass ejection (CME). Similar processes may have occurred in other recently-studied events, NASA supported this work through NASA SR&T and SEC GI grants.

Long-term financing needs for HIV control in sub-Saharan Africa in 2015–2050: a modelling study

PubMed Central

Atun, Rifat; Chang, Angela Y; Ogbuoji, Osondu; Silva, Sachin; Resch, Stephen; Hontelez, Jan; Bärnighausen, Till

2016-01-01

Objectives To estimate the present value of current and future funding needed for HIV treatment and prevention in 9 sub-Saharan African (SSA) countries that account for 70% of HIV burden in Africa under different scenarios of intervention scale-up. To analyse the gaps between current expenditures and funding obligation, and discuss the policy implications of future financing needs. Design We used the Goals module from Spectrum, and applied the most up-to-date cost and coverage data to provide a range of estimates for future financing obligations. The four different scale-up scenarios vary by treatment initiation threshold and service coverage level. We compared the model projections to current domestic and international financial sources available in selected SSA countries. Results In the 9 SSA countries, the estimated resources required for HIV prevention and treatment in 2015–2050 range from US$98 billion to maintain current coverage levels for treatment and prevention with eligibility for treatment initiation at CD4 count of <500/mm3 to US$261 billion if treatment were to be extended to all HIV-positive individuals and prevention scaled up. With the addition of new funding obligations for HIV—which arise implicitly through commitment to achieve higher than current treatment coverage levels—overall financial obligations (sum of debt levels and the present value of the stock of future HIV funding obligations) would rise substantially. Conclusions Investing upfront in scale-up of HIV services to achieve high coverage levels will reduce HIV incidence, prevention and future treatment expenditures by realising long-term preventive effects of ART to reduce HIV transmission. Future obligations are too substantial for most SSA countries to be met from domestic sources alone. New sources of funding, in addition to domestic sources, include innovative financing. Debt sustainability for sustained HIV response is an urgent imperative for affected countries and donors. PMID:26948960

Initiation of Solar Eruptions

NASA Technical Reports Server (NTRS)

Sterling, Alphonse C.; Moore, Ronald L.

2007-01-01

We consider processes occurring just prior to and at the start of the onset of flare- and CME-producing solar eruptions. Our recent work uses observations of filament motions around the time of eruption onset as a proxy for the evolution of the fields involved in the eruption. Frequently the filaments show a slow rise prior to fast eruption, indicative of a slow expansion of the field that is about co explode. Work by us and others suggests that reconnection involving emerging or canceling flux results in a lengthening of fields restraining the filament-carrying field, and the consequent upward expansion of the field in and around the filament produces the filament's slow rise: that is, the reconnection weakens the magnetic "tethers" ("tether-weakening" reconnection), and results in the slow rise of the filament. It is still inconclusive, however, what mechanism is responsible for the switch from the slow rise to the fast eruption.

Space charge effects on the current-voltage characteristics of gated field emitter arrays

NASA Astrophysics Data System (ADS)

Jensen, K. L.; Kodis, M. A.; Murphy, R. A.; Zaidman, E. G.

1997-07-01

Microfabricated field emitter arrays (FEAs) can provide the very high electron current densities required for rf amplifier applications, typically on the order of 100 A/cm2. Determining the dependence of emission current on gate voltage is important for the prediction of emitter performance for device applications. Field emitters use high applied fields to extract current, and therefore, unlike thermionic emitters, the current densities can exceed 103A/cm2 when averaged over an array. At such high current densities, space charge effects (i.e., the influence of charge between cathode and collector on emission) affect the emission process or initiate conditions which can lead to failure mechanisms for field emitters. A simple model of a field emitter will be used to calculate the one-dimensional space charge effects on the emission characteristics by examining two components: charge between the gate and anode, which leads to Child's law, and charge within the FEA unit cell, which gives rise to a field suppression effect which can exist for a single field emitter. The predictions of the analytical model are compared with recent experimental measurements designed to assess space charge effects and predict the onset of gate current. It is shown that negative convexity on a Fowler-Nordheim plot of Ianode(Vgate) data can be explained in terms of field depression at the emitter tip in addition to reflection of electrons by a virtual cathode created when the anode field is insufficient to extract all of the current; in particular, the effects present within the unit cell constitute a newly described effect.

Techno-economical Analysis of Rooftop Grid-connected PV Dairy Farms; Case Study of Urmia University Dairy Farm

NASA Astrophysics Data System (ADS)

Nikbakht, A. M.; Aste, N.; Sarnavi, H. J.; Leonforte, F.

2017-08-01

The global trends indicate a growing commitment to renewable energy development because of declining fossil fuels and environmental threats. Moreover, the global demographic growth coupled with rising demands for food has escalated the rate of energy consumption in food section. This study aims to investigate the techno-economic impacts of a grid-connected rooftop PV plan applied for a educational dairy farm in Urmia university, with total estimated annual electrical energy consumption of 18,283 kWh, located at the north west part of Iran. Based on the current feed-in tariff and tremendously low electricity price in agriculture section in Iran, the plants with size ranged from 14.4 to 19.7 kWp (initial investment ranged from 26,000 to 36,000 USD) would be satisfied economically.

The North Carolina State Health Plan for Teachers and State Employees: Strategies in Creating Financial Stability While Improving Member Health.

PubMed

Jones, Dee; Horner, Beth

2018-01-01

The North Carolina State Health Plan provides health care coverage to more than 700,000 members, including teachers, state employees, retirees, current and former lawmakers, state university and community college personnel, and their dependents. The State Health Plan is a division of the North Carolina Department of State Treasurer, self-insured, and exempt from the Employee Retirement Income Security Act as a government-sponsored plan. With health care costs rising at rates greater than funding, the Plan must take measures to stem cost growth while ensuring access to quality health care. The Plan anticipates focusing on strategic initiatives that drive results and cost savings while improving member health to protect the Plan's financial future. ©2018 by the North Carolina Institute of Medicine and The Duke Endowment. All rights reserved.

Trans-cranial focused ultrasound without hair shaving: feasibility study in an ex vivo cadaver model

PubMed Central

2013-01-01

In preparing a patient for a trans-cranial magnetic resonance (MR)-guided focused ultrasound procedure, current practice is to shave the patient’s head on treatment day. Here we present an initial attempt to evaluate the feasibility of trans-cranial focused ultrasound in an unshaved, ex vivo human head model. A human skull filled with tissue-mimicking phantom and covered with a wig made of human hair was sonicated using 220- and 710-kHz head transducers to evaluate the feasibility of acoustic energy transfer. Heating at the focal point was measured by MR proton resonance shift thermometry. Results showed that the hair had a negligible effect on focal spot thermal rise at 220 kHz and a 17% drop in temperature elevation when using 710 kHz. PMID:25512865

Effects of Marijuana Use on Brain Structure and Function: Neuroimaging Findings from a Neurodevelopmental Perspective

PubMed Central

Brumback, T.; Castro, N.; Jacobus, J.; Tapert, S.

2016-01-01

Marijuana, behind only tobacco and alcohol, is the most popular recreational drug in America with prevalence rates of use rising over the past decade. A wide range of research has highlighted neurocognitive deficits associated with marijuana use, particularly when initiated during childhood or adolescence. Neuroimaging, describing alterations to brain structure and function, has begun to provide a picture of possible mechanisms associated with the deleterious effects of marijuana use. This chapter provides a neurodevelopmental framework from which recent data on brain structural and functional abnormalities associated with marijuana use is reviewed. Based on the current data, we provide aims for future studies to more clearly delineate the effects of marijuana on the developing brain and to define underlying mechanisms of the potential long-term negative consequences of marijuana use. PMID:27503447

Thermal buckling behavior of defective CNTs under pre-load: A molecular dynamics study.

PubMed

Mehralian, Fahimeh; Tadi Beni, Yaghoub; Kiani, Yaser

2017-05-01

Current study is concentrated on the extraordinary properties of defective carbon nanotubes (CNTs). The role of vacancy defects in thermal buckling response of precompressed CNTs is explored via molecular dynamics (MD) simulations. Defective CNTs are initially compressed at a certain ratio of their critical buckling strain and then undergo a uniform temperature rise. Comprehensive study is implemented on both armchair and zigzag CNTs with different vacancy defects including monovacancy, symmetric bivacancy and asymmetric bivacancy. The results reveal that defects have a pronounced impact on the buckling behavior of CNTs; interestingly, defective CNTs under compressive pre-load show higher resistance to thermal buckling than pristine ones. In the following, the buckling response of defective CNTs is shown to be dependent on the vacancy defects, location of defects and chirality. Copyright © 2017 Elsevier Inc. All rights reserved.

Post-Impact Fatigue Damage Monitoring Using Fiber Bragg Grating Sensors

PubMed Central

Shin, Chow-Shing; Liaw, Shien-Kuei; Yang, Shi-Wei

2014-01-01

It has been shown that impact damage to composite materials can be revealed by embedded Fiber Bragg Gratings (FBG) as a broadening and splitting of the latter's characteristic narrow peak reflected spectrum. The current work further subjected the impact damaged composite to cyclic loading and found that the FBG spectrum gradually submerged into a rise of background intensity as internal damages progressed. By skipping the impact, directing the impact to positions away from the FBG and examining the extracted fibers, we concluded that the above change is not a result of deterioration/damage of the sensor. It is caused solely by the damages initiated in the composite by the impact and aggravated by fatigue loading. Evolution of the grating spectrum may therefore be used to monitor qualitatively the development of the incurred damages. PMID:24594609

Planetary Cartography - Activities and Current Challenges

NASA Astrophysics Data System (ADS)

Nass, Andrea; Di, Kaichang; Elgner, Stephan; van Gasselt, Stephan; Hare, Trent; Hargitai, Henrik; Karachevtseva, Irina; Kereszturi, Akos; Kersten, Elke; Kokhanov, Alexander; Manaud, Nicolas; Roatsch, Thomas; Rossi, Angelo Pio; Skinner, James, Jr.; Wählisch, Marita

2018-05-01

Maps are one of the most important tools for communicating geospatial information between producers and receivers. Geospatial data, tools, contributions in geospatial sciences, and the communication of information and transmission of knowledge are matter of ongoing cartographic research. This applies to all topics and objects located on Earth or on any other body in our Solar System. In planetary science, cartography and mapping have a history dating back to the roots of telescopic space exploration and are now facing new technological and organizational challenges with the rise of new missions, new global initiatives, organizations and opening research markets. The focus of this contribution is to introduce the community to the field of planetary cartography and its historic foundation, to highlight some of the organizations involved and to emphasize challenges that Planetary Cartography has to face today and in the near future.

Effect of process parameters on metal transfer of hyperbaric GMAW of duplex stainless steels

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

Olsen, J.M.; Dos Santos, J.F.; Richardson, I.M.

1994-12-31

This work presents the preliminary results of a comprehensive and systematic evaluation of current rise and fall rates as well as shielding gas composition and their affect on the metal transfer, when duplex stainless steels are GMA welded under hyperbaric conditions using the short circuit metal transfer mode. The evaluation of the test results are based on an examination of the welding process signals recorded on a transient recorder. Over a time period of 500 ms, the signal was measured to assess the process instability, current rise and fall rates and their inter-relationship. The results presented in this study indicatemore » that for a given welding condition, the appropriate selection of current rise and fall rates can minimize the effect of instabilities caused by high ambient pressure. The presence of active gases in the shielding did not significantly affect the metal transfer behavior. All the experiments described in this work have been carried out in the hyperbaric test facilities of the GKSS-Forschungszentrum in Germany.« less

Observations of a bi-directional lightning leader producing an M-component

NASA Astrophysics Data System (ADS)

Kotovsky, D. A.; Uman, M. A.; Wilkes, R.; Carvalho, F. L.; Jordan, D. M.

2017-12-01

Lightning discharges to ground often exhibit millisecond-scale surges in the continuing currents following return strokes, called M-components. Relatively little is known regarding the source of M-component charge and the mechanisms by which that charge is transferred to ground. In this work, we seek to directly address these questions by presenting correlated high-speed video and Lightning Mapping Array (LMA) observations of a bi-directional leader that resulted in an M-component occurring in a rocket-and-wire triggered lightning flash. The observed leader initiated in the decayed remnants of a positive leader channel that had traversed virgin air approximately 90 msec prior. Three-dimensional locations and speeds of the photographed bi-directional leader and M-component processes are calculated by mapping video images to the observed LMA channel geometry. Both ends of the bi-directional leader exhibited speeds on the order of 2 x106 m sec-1 over 570 meters of the visible channel. Propagation of the luminosity wave from the in-cloud leader to ground ( 8.8 km channel length) exhibited appreciable dispersion, with rise-times (10-90%) increasing from 330 to 410 μsec and pulse-widths (half-maximum) increasing from 380 to 810 μsec - the M-component current pulse measured at ground-level exhibited a rise-time of 290 μsec and a pulse-width of 770 μsec. Group velocities of the luminosity wave have been calculated as a function of frequency, increasing from 2 x107 to 6 x107 m sec-1 over the dominant signal bandwidth (DC to 2 kHz). Additionally, multiple waves of luminosity are observed within the in-cloud channel, indicating nuanced wave phenomena possibly associated with reflection from the end of the leader channel and attachment with the main lightning channel carrying continuing current to ground.

Precision Medicine and a Patient-Orientated Approach: Is this the Future for Tracking Cardiovascular Disorders?

PubMed

Pretorius, Etheresia

2017-01-01

The latest statistics from the 2016 heart disease and stroke statistics update shows that cardiovascular disease is the leading global cause of death, currently accounting for more than 17.3 million deaths per year. Type II diabetes is also on the rise with out-of-control numbers. To address these pandemics, we need to treat patients using an individualized patient care approach, but simultaneously gather data to support the precision medicine initiative. Last year the NIH announced the precision medicine initiative to generate novel knowledge regarding diseases, with a near-term focus on cancers, followed by a longer-term aim, applicable to a whole range of health applications and diseases. The focus of this paper is to suggest a combined effort between the latest precision medicine initiative, researchers and clinicians; whereby novel techniques could immediately make a difference in patient care, but long-term add to knowledge for use in precision medicine. We discuss the intricate relationship between individualized patient care and precision medicine and the current thoughts regarding which data is actually suitable for the precision medicine data gathering. The uses of viscoelastic techniques in precision medicine are discussed and how these techniques might give novel perspectives on the success of treatment regimes of cardiovascular patients are explored. Thrombo-embolic stroke, rheumathoid arthritis and type II diabetes are used as examples of diseases where precision medicine and a patient-orientated approach can possibly be implemented. In conclusion it is suggested that if all role players work together by embracing a new way of thought in treating and managing cardiovascular disease and diabetes will we be able to adequately address these out-ofcontrol conditions. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Analysis of Required Supporting Systems for the Supercritical CO(2) Power Conversion System

DTIC Science & Technology

2007-09-01

been drawn to the viability of using S-C02 as a working fluid in modern reactor designs. Near the critical point, C02 has a rapid rise in density...viability of using S-CO2 as a working fluid in modern reactor designs. Near the critical point, CO2 has a rapid rise in density allowing a significant...32 Figure 2.2.3 Effect on Mass Transferred of Changing ICV Initial Temperature for emptying PCS ...................32 Figure 2.2.4 Effect

Family Medicine in a Consumer Age — Part 4: Preventive Medicine, Professional Satisfaction, and the Rise of Consumerism

PubMed Central

Warner, Morton M.

1977-01-01

In an attempt to find out if the physician perceives the same strengths and weaknesses in today's practice of family medicine as does the consumer, the Lay Advisory Committee of the College's B.C. Chapter initiated a survey of physicians' and consumers' attitudes. This article, the fourth and last in a series, presents some of the results of the survey as they relate to preventive-medicine, professional satisfaction and the rise of consumerism.

Primed for Reform: A District's Use of Existing Assets to Drive Improvement

ERIC Educational Resources Information Center

Region IX Equity Assistance Center at WestEd, 2014

2014-01-01

This brief reports on the early stages and initial successes of turnaround efforts in a California school district. With administrators and educators in the midst of implementing a robust reform agenda, there are clear signs that the district is on the rise. The reform initiatives have stopped a downward slide in student attendance, behavior, and…

Cardioembolic Stroke.

PubMed

O'Carroll, Cumara B; Barrett, Kevin M

2017-02-01

Cardioembolic stroke is common and disproportionately more disabling than nonembolic mechanisms of stroke. Its incidence is expected to rise because of the age-related incidence of atrial fibrillation and an aging population. This article summarizes the different causes of cardioembolism and outlines current management guidelines. Since cardioembolic stroke is not a single disease entity, its diagnosis requires initial clinical suspicion and a comprehensive evaluation, including ECG, echocardiography, brain imaging, and cardiac monitoring. Atrial fibrillation is the most common cause of cardioembolic stroke, and anticoagulation is usually recommended. This article reviews risk stratification models to assist in the decision-making process and highlights the increased use of novel oral anticoagulants for stroke prevention in atrial fibrillation. New data support the importance of prolonged cardiac monitoring for diagnosing occult atrial fibrillation. Current data on other mechanisms of cardioembolic stroke, such as prosthetic heart valves and aortic arch atherosclerosis, are also presented, and the available evidence regarding patent foramen ovale closure in cryptogenic stroke is summarized. Cardioembolism is an important cause of ischemic stroke, with diverse underlying mechanisms requiring a tailored approach to diagnosis, management, and prevention.

SAR and thermal response effects of a two-arm Archimedean spiral coil in a magnetic induction sensor on a human head.

PubMed

Zhang, Ziyi; Liu, Peiguo; Zhou, Dongming; Zhang, Liang; Ding, Liang

2015-01-01

This study investigates the radiation safety of a newly designed magnetic induction sensor. This novel magnetic induction sensor uses a two-arm Archimedean spiral coil (TAASC) as the exciter. A human head model with a real anatomical structure was used to calculate the specific absorption rate (SAR) and temperature change. Computer Simulation Technology (CST) was used to determine the values of the peak 10-g SAR under different operating parameters (current, frequency, horizontal distance between the excitation coil and the receiver coil, vertical distance between the top of the head model and the XOY plane, position of excitation coil, and volume of hemorrhage). Then, the highest response for the SAR and temperature rise was determined. The results showed that this new magnetic induction sensor is safe in the initial state; for safety reasons, the TAASC current should not exceed 4 A. The scalp tissue absorbed most of the electromagnetic energy. The TAASC's SAR/thermal performance was close to that of the circular coil.

Malignancies in HIV-Infected and AIDS Patients.

PubMed

Ji, Yongjia; Lu, Hongzhou

2017-01-01

Currently, HIV infection and AIDS are still one of the most important epidemic diseases around the world. As early in the initial stage of HIV epidemic, the high incidence of ADCs including Kaposi sarcoma and non-Hodgkin's lymphoma was the substantial amount of disease burden of HIV infection and AIDS. With the increasing accessibility of HAART and improving medical care for HIV infection and AIDS, AIDS-related illness including ADCs has dramatically decreased. Meanwhile, the incidence of NADCs rises in PLWH. Compared with the general population, most of cancers are more likely to attack PLWH, and NADCs in PLWH were characterized as earlier onset and more aggressive. However, the understanding for cancer development in PLWH is still dimness. Herein, we reviewed the current knowledge of epidemiology and pathogenesis for malignancies in PLWH summarized from recent studies. On the basis of that, we discussed the special considerations for cancer treatment in PLWH. As those malignancies could be the major issue for HIV infection or AIDS in the future, we expect enhanced investigations, surveillances, and clinical trial for improving the understanding and management for cancers developed in PLWH.

Assessing water quality of the Chesapeake Bay by the impact of sea level rise and warming

NASA Astrophysics Data System (ADS)

Wang, P.; Linker, L.; Wang, H.; Bhatt, G.; Yactayo, G.; Hinson, K.; Tian, R.

2017-08-01

The influence of sea level rise and warming on circulation and water quality of the Chesapeake Bay under projected climate conditions in 2050 were estimated by computer simulation. Four estuarine circulation scenarios in the estuary were run using the same watershed load in 1991-2000 period. They are, 1) the Base Scenario, which represents the current climate condition, 2) a Sea Level Rise Scenario, 3) a Warming Scenario, and 4) a combined Sea Level Rise and Warming Scenario. With a 1.6-1.9°C increase in monthly air temperatures in the Warming Scenario, water temperature in the Bay is estimated to increase by 0.8-1°C. Summer average anoxic volume is estimated to increase 1.4 percent compared to the Base Scenario, because of an increase in algal blooms in the spring and summer, promotion of oxygen consumptive processes, and an increase of stratification. However, a 0.5-meter Sea Level Rise Scenario results in a 12 percent reduction of anoxic volume. This is mainly due to increased estuarine circulation that promotes oxygen-rich sea water intrusion in lower layers. The combined Sea Level Rise and Warming Scenario results in a 10.8 percent reduction of anoxic volume. Global warming increases precipitation and consequently increases nutrient loads from the watershed by approximately 5-7 percent. A scenario that used a 10 percent increase in watershed loads and current estuarine circulation patterns yielded a 19 percent increase in summer anoxic volume, while a scenario that used a 10 percent increase in watershed loads and modified estuarine circulation patterns by the aforementioned sea level rise and warming yielded a 6 percent increase in summer anoxic volume. Impacts on phytoplankton, sediments, and water clarity were also analysed.

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.

Supershort avalanche electron beam in SF6 and krypton

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Tarasenko, Victor F.; Gu, Jianwei; Baksht, Evgeni Kh.; Beloplotov, Dmitry V.; Burachenko, Alexander G.; Yan, Ping; Lomaev, Mikhail I.; Shao, Tao

2016-03-01

Runaway electrons play an important role in the avalanche formation in nanosecond- and subnanosecond- pulse discharges. In this paper, characteristics of a supershort avalanche electron beam (SAEB) generated at the subnanosecond and nanosecond breakdown in sulfur hexafluoride (SF6 ) in an inhomogeneous electric field were studied. One pulser operated at negative polarity with voltage pulse amplitude of ˜130 kV and rise time of 0.3 ns. The other pulser operated at negative polarity with voltage pulse amplitude of 70 kV and rise time of ˜1.6 ns . SAEB parameters in SF6 are compared with those obtained in krypton (Kr), nitrogen (N2 ), air, and mixtures of SF6 with krypton or nitrogen. Experimental results showed that SAEB currents appeared during the rise-time of the voltage pulse for both pulsers. Moreover, amplitudes of the SAEB current in SF6 and Kr approximately ranged from several to tens of milliamps at atmospheric pressure, which were smaller than those in N2 and air (ranging from hundreds of milliamps to several amperes). Furthermore, the concentration of SF6 additive could significantly reduce the SAEB current in N2-SF6 mixture, but it slightly affected the SAEB current in Kr -SF6 mixture because of the atomic/molecular ionization cross section of the gas had a much greater impact on the SAEB current rather than the electronegativity.

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.

Analysis of the Pressure Rise in a Partially Filled Liquid Tank in Microgravity with Low Wall Heat Flux and Simultaneous Boiling and Condensation

NASA Technical Reports Server (NTRS)

Hasan, Mohammad M.; Balasubramaniam, R.

2012-01-01

Experiments performed with Freon 113 in the space shuttle have shown that in a pro- cess of very slow heating, high liquid superheats can be sustained for a long period in microgravity. In a closed system explosive vaporization of superheated liquid resulted in pressure spikes of varying magnitudes. In this paper, we analyze the pressure rise in a partially lled closed tank in which a large vapor bubble (i.e., ullage) is initially present, and the liquid is subjected to a low wall heat ux. The liquid layer adjacent to the wall becomes superheated until the temperature for nucleation of the bubbles (or the incipience of boiling) is achieved. In the absence of the gravity-induced convection large quantities of superheated liquid can accumulate over time near the heated surface. Once the incipience temperature is attained, explosive boiling occurs and the vapor bubbles that are produced on the heater surface tend to quickly raise the tank pressure. The liquid-vapor saturation temperature increases as well. These two e ects tend to induce condensation of the large ullage bubble that is initially present, and tends to mitigate the tank pressure rise. As a result, the tank pressure is predicted to rise sharply, attain a maximum, and subsequently decay slowly. The predicted pressure rise is compared with experimental results obtained in the microgravity environments of the space shuttle for Freon 113. The analysis is appli- cable, in general to heating of liquid in closed containers in microgravity and to cryogenic fuel tanks, in particular where small heat leaks into the tank are unavoidable.

Dielectric property study of poly(4-vinylphenol)-graphene oxide nanocomposite thin film

NASA Astrophysics Data System (ADS)

Roy, Dhrubojyoti

2018-05-01

Thin film capacitor device having a sandwich structure of indium tin oxide (ITO)-coated glass/polymer or polymer nanocomposite /silver has been fabricated and their dielectric and leakage current properties has been studied. The dielectric properties of the capacitors were characterized for frequencies ranging from 1 KHz to 1 MHz. 5 wt% Poly(4-vinylphenol)(PVPh)-Graphene (GO) nanocomposite exhibited an increase in dielectric constant to 5.6 and small rise in dielectric loss to around˜0.05 at 10 KHz w.r.t polymer. The DC conductivity measurements reveal rise of leakage current in nanocomposite.

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

Majzoobi, A.; Joshi, R. P., E-mail: ravi.joshi@ttu.edu; Neuber, A. A.

Particle-in-cell simulations are performed to analyze the efficiency, output power and leakage currents in a 12-Cavity, 12-Cathode rising-sun magnetron with diffraction output (MDO). The central goal is to conduct a parameter study of a rising-sun magnetron that comprehensively incorporates performance enhancing features such as transparent cathodes, axial extraction, the use of endcaps, and cathode extensions. Our optimum results demonstrate peak output power of about 2.1 GW, with efficiencies of ∼70% and low leakage currents at a magnetic field of 0.45 Tesla, a 400 kV bias with a single endcap, for a range of cathode extensions between 3 and 6 centimeters.

Wildland fire emissions, carbon, and climate: Plume rise, atmospheric transport, and chemistry processes

Treesearch

Warren Heilman; Yongqiang Liu; Shawn Urbanski; Vladimir Kovalev; Robert Mickler

2014-01-01

This paper provides an overview and summary of the current state of knowledge regarding critical atmospheric processes that affect the distribution and concentrations of greenhouse gases and aerosols emitted from wildland fires or produced through subsequent chemical reactions in the atmosphere. These critical atmospheric processes include the dynamics of plume rise,...

Identification of cells initiating human melanomas

PubMed Central

Schatton, Tobias; Murphy, George F.; Frank, Natasha Y.; Yamaura, Kazuhiro; Waaga-Gasser, Ana Maria; Gasser, Martin; Zhan, Qian; Jordan, Stefan; Duncan, Lyn M.; Weishaupt, Carsten; Fuhlbrigge, Robert C.; Kupper, Thomas S.; Sayegh, Mohamed H.; Frank, Markus H.

2012-01-01

Tumour-initiating cells capable of self-renewal and differentiation, which are responsible for tumour growth, have been identified in human haematological malignancies1,2 and solid cancers3–6. If such minority populations are associated with tumour progression in human patients, specific targeting of tumour-initiating cells could be a strategy to eradicate cancers currently resistant to systemic therapy. Here we identify a subpopulation enriched for human malignant-melanoma-initiating cells (MMIC) defined by expression of the chemoresistance mediator ABCB5 (refs 7, 8) and show that specific targeting of this tumorigenic minority population inhibits tumour growth. ABCB5+ tumour cells detected in human melanoma patients show a primitive molecular phenotype and correlate with clinical melanoma progression. In serial human-to-mouse xenotransplantation experiments, ABCB5+ melanoma cells possess greater tumorigenic capacity than ABCB5− bulk populations and re-establish clinical tumour heterogeneity. In vivo genetic lineage tracking demonstrates a specific capacity of ABCB5+ sub-populations for self-renewal and differentiation, because ABCB5+ cancer cells generate both ABCB5+ and ABCB5− progeny, whereas ABCB5− tumour populations give rise, at lower rates, exclusively to ABCB5− cells. In an initial proof-of-principle analysis, designed to test the hypothesis that MMIC are also required for growth of established tumours, systemic administration of a monoclonal antibody directed at ABCB5, shown to be capable of inducing antibody-dependent cell-mediated cytotoxicity in ABCB5+ MMIC, exerted tumour-inhibitory effects. Identification of tumour-initiating cells with enhanced abundance in more advanced disease but susceptibility to specific targeting through a defining chemoresistance determinant has important implications for cancer therapy. PMID:18202660

Initial-boundary layer associated with the nonlinear Darcy-Brinkman-Oberbeck-Boussinesq system

NASA Astrophysics Data System (ADS)

Fei, Mingwen; Han, Daozhi; Wang, Xiaoming

2017-01-01

In this paper, we study the vanishing Darcy number limit of the nonlinear Darcy-Brinkman-Oberbeck-Boussinesq system (DBOB). This singular perturbation problem involves singular structures both in time and in space giving rise to initial layers, boundary layers and initial-boundary layers. We construct an approximate solution to the DBOB system by the method of multiple scale expansions. The convergence with optimal convergence rates in certain Sobolev norms is established rigorously via the energy method.

Failure Mode Analysis of V-Shaped Pyrotechnically Actuated Valves

NASA Technical Reports Server (NTRS)

Sachdev, Jai S.; Hosangadi, A.; Chenoweth, James D.; Saulsberry, Regor L.; McDougle, Stephen H.

2012-01-01

Current V-shaped stainless steel pyrovalve initiators have rectified many of the deficiencies of the heritage Y-shaped aluminum design. However, a credible failure mode still exists for dual simultaneous initiator (NSI) firings in which low temperatures were detected at the booster cap and less consistent ignition was observed than when a single initiator was fired. In order to asses this issue, a numerical framework has been developed for predicting the flow through pyrotechnically actuated valves. This framework includes a fully coupled solution of the gas-phase equation with a non-equilibrium dispersed phase for solid particles as well as the capability to model conjugate gradient heat transfer to the booster cap. Through a hierarchy of increasingly complex simulations, a hypothesis for the failure mode of the nearly simultaneous dual NSI firings has been proven. The simulations indicate that the failure mode for simultaneous dual NSI firings may be caused by flow interactions between the flame channels. The shock waves from each initiator interact in the booster cavity resulting in a high pressure that prevents the gas and particulate velocity from rising in the booster cap region. This impedes the bulk of the particulate phase from impacting the booster cap and reduces the heat transfer to the booster cap since the particles do not impact it. Heat transfer calculations to the solid metal indicate that gas-phase convective heat transfer may not be adequate by itself and that energy transfer from the particulate phase may be crucial for the booster cap burn through.

Nuclear Bombs and Coral: Guam Coral Core Reveals Operation-Specific Radiocarbon Signals from the Pacific Proving Grounds

NASA Astrophysics Data System (ADS)

Andrews, A. H.

2016-12-01

Radiocarbon (14C) analyses on a coral core extracted from the western Central Pacific (Guam) has revealed a series of early peaks in the marine bomb 14C record. The typical marine bomb 14C signal, one that is phase lagged and attenuated relative to atmospheric bomb 14C, is present in the coral core and is consistent with other North Pacific records. However, 14C levels that are well above what can be explained by air-sea diffusion alone punctuate this pattern. This anomaly has been demonstrated to a limited extent in other coral cores of the Indo-Pacific region, but is unmatched relative to the magnitude and temporal resolution recorded in the Guam coral core. Other records have shown an early Δ14C rise on the order of 40-50‰ above pre-bomb levels, with a subsequent decline before continuing the gradual Δ14C rise that is indicative of air-sea diffusion of 14CO2. The Guam coral Δ14C record provided three strong pulses in 1954-55, 1956-57, and 1958-59 that are superimposed on the pre-bomb to initial Δ14C rise from atmospheric bomb 14C. Each of these peaks can be directly linked to testing of thermonuclear devices in the Pacific Proving Grounds at Eniwetok and Bikini Atoll of the Marshall Islands. The measurable lag in reaching Guam can be tied to ocean surface currents and can be traced to other regional Δ14C records from corals, providing a transport timeline to places as distant as the Indonesian throughflow, Okinawa and Palmyra.

Channel formation by flow stripping: large-scale scour features along the Monterey East Channel and their relation to sediment waves

USGS Publications Warehouse

Fildani, A.; Normark, W.R.; Kostic, S.; Parker, G.

2006-01-01

The Monterey East system is formed by large-scale sediment waves deposited as a result of flows stripped from the deeply incised Monterey fan valley (Monterey Channel) at the apex of the Shepard Meander. The system is dissected by a linear series of steps that take the form of scour-shaped depressions ranging from 3·5 to 4·5 km in width, 3 to 6 km in length and from 80 to 200 m in depth. These giant scours are aligned downstream from a breech in the levee on the southern side of the Shepard Meander. The floor of the breech is only 150 m above the floor of the Monterey fan valley but more than 100 m below the levee crests resulting in significant flow stripping. Numerical modeling suggests that the steps in the Monterey East system were created by Froude-supercritical turbidity currents stripped from the main flow in the Monterey channel itself. Froude-supercritical flow over an erodible bed can be subject to an instability that gives rise to the formation of cyclic steps, i.e. trains of upstream-migrating steps bounded upstream and downstream by hydraulic jumps in the flow above them. The flow that creates these steps may be net-erosional or net-depositional. In the former case it gives rise to trains of scours such as those in the Monterey East system, and in the latter case it gives rise to the familiar trains of upstream-migrating sediment waves commonly seen on submarine levees. The Monterey East system provides a unique opportunity to introduce the concept of cyclic steps in the submarine environment to study processes that might result in channel initiation on modern submarine fans.

An economic analysis of different cannabis decriminalization scenarios.

PubMed

Ogrodnik, Marysia; Kopp, Pierre; Bongaerts, Xavier; Tecco, Juan M

2015-09-01

Cannabis is the most widely used illegal drug in European countries. In countries with repressive cannabis policies, prevalence is not lower than in those with tolerant laws. Repressive policies not only have uncertain benefits but they are also expensive. Economists tend to believe that good public policies minimize social costs; that is, they help to improve collective wellbeing at a lower cost. The paper draws on a review of international literature on cannabis legislative models around the world. After a description of some of the fundamental concepts of a market economy, several existing policy scenarios will be presented and analyzed from an economic perspective. Strength and weaknesses will be summarized for each alternative. In addition to consumption tolerance in countries such as the Netherlands, recent decriminalization of domestic markets in the Unites States and Uruguay present alternatives to reduce the negative impact of cannabis on society. Earlier initiation age and rise in consumption are unintended potential consequences of decriminalization that need to be addressed by public authorities when designing a liberalized cannabis policy environment. Price is a key variable that needs to be addressed to prevent a rise in consumption. Repressive cannabis policies are expensive and have limited impact on consumption. Consumption legalization significantly reduces expenses for repression and law enforcement, allowing for the allocation of more resources to other targets such as education and prevention. With legalization of supply along with consumption, repression and law enforcement costs are reduced even further. Moreover, a legal market would create employment and generate tax revenues that could be allocated to the prevention of increased consumption. Legalizing cannabis would not lead to a sudden rise in consumption, providing the duty imposed by the state kept the product at its current price.

Defining Health in the Era of Value-based Care: Lessons from England of Relevance to Other Health Systems.

PubMed

Gentry, Sarah; Badrinath, Padmanabhan

2017-03-06

The demand for healthcare is rising due to aging populations, rising chronic disease prevalence, and technological innovations. There are currently more effective and cost-effective interventions available than can be afforded within limited budgets. A new way of thinking about the optimal use of resources is needed. Ensuring that available resources are used for interventions that provide outcomes that patient's most value, rather than a focus just on effectiveness and cost-effectiveness, may help to ensure that resources are used optimally. Value-based healthcare puts what patients value at the center of healthcare. It helps ensure that they receive the care that can provide them with outcomes they think are important and that limited resources are focused on high-value interventions. In order to do this, we need flexible definitions of 'health', personalized and tailored to patient values. We review the current status of value-based health care in England and identify lessons applicable to a variety of health systems. For this, we draw upon the work of the National Institute for Health and Care Excellence (NICE), the National Health Service (NHS), Right Care Initiative, and our local experience in promoting value-based health care for specific conditions in our region. Combining the best available evidence with open and honest dialogue between patients, clinicians, and others, whilst requiring considerable time and resources are essential to building a consensus around the value that allows the best use of limited budgets. Values have been present in healthcare since its beginnings. Placing value and values at the center of healthcare could help to ensure available resources are used to provide the greatest possible benefit to patients.

Diminished Wastewater Treatment: Evaluation of Septic System Performance Under a Climate Change Scenario

NASA Astrophysics Data System (ADS)

Cooper, J.; Loomis, G.; Kalen, D.; Boving, T. B.; Morales, I.; Amador, J.

2015-12-01

The effects of climate change are expected to reduce the ability of soil-based onsite wastewater treatment systems (OWTS), to treat domestic wastewater. In the northeastern U.S., the projected increase in atmospheric temperature, elevation of water tables from rising sea levels, and heightened precipitation will reduce the volume of unsaturated soil and oxygen available for treatment. Incomplete removal of contaminants may lead to transport of pathogens, nutrients, and biochemical oxygen demand (BOD) to groundwater, increasing the risk to public health and likelihood of eutrophying aquatic ecosystems. Advanced OWTS, which include pre-treatment steps and provide unsaturated drainfields of greater volume relative to conventional OWTS, are expected to be more resilient to climate change. We used intact soil mesocosms to quantify water quality functions for two advanced shallow narrow drainfield types and a conventional drainfield under a current climate scenario and a moderate climate change scenario of 30 cm rise in water table and 5°C increase in soil temperature. While no fecal coliform bacteria (FCB) was released under the current climate scenario, up to 109 CFU FCB/mL (conventional) and up to 20 CFU FCB/mL (shallow narrow) were released under the climate change scenario. Total P removal rates dropped from 100% to 54% (conventional) and 71% (shallow narrow) under the climate change scenario. Total N removal averaged 17% under both climate scenarios in the conventional, but dropped from 5.4% to 0% in the shallow narrow under the climate change scenario, with additional leaching of N in excess of inputs indicating release of previously held N. No significant difference was observed between scenarios for BOD removal. The initial data indicate that while advanced OWTS retain more function under the climate change scenario, all three drainfield types experience some diminished treatment capacity.

Evaluating Potential Tipping Points of Antarctic basins

NASA Astrophysics Data System (ADS)

Durand, G.; Sainan, S.; Pattyn, F.; Jourdain, N.

2017-12-01

Antarctica is currently loosing mass and its forthcoming contribution to sea-level rise could substantially increase during the coming centuries. This is essentially due to geometrical constraints, i.e., in regions where grounded ice lies on a bedrock below sea-level sloping down towards the interior of the ice sheet (retrograde slope). For such a configuration the ice sheet is considered potentially unstable, as suggested by theory. However, recent observations on accelerated grounding-line retreat and new insights in modeling Pine Island and Thwaites glaciers give evidence that such self-sustained retreat, called marine ice sheet instability (MISI), has already been on its way. Although West Antarctica appears to be the most vulnerable region for MISI occurrence, similar topographic configurations are also observed in East Antarctica, in the Wilkes Basin in particular. Therefore, evaluating the MISI potential at a pan-Antarctic scale is becoming a priority. Here, using the f.ETISh ice sheet model, an ensemble of simulations of the entire contemporary Antarctic ice sheet has been carried out. In particular, we investigate the debuttressing of ice shelves required to initiate MISI for each coastal region around Antarctica by forcing the model with realistic sub-shelf melt pulses of varying duration and amplitude. We further identify the currently grounded areas where the outlet glaciers could hardly stabilize, the Amundsen Sea Sector being the more prone to large self-sustained retreats. On the contrary, the ability of Cook and Ninnis ice shelves to recover after large perturbations and enough buttress upstream outlet glaciers tends to limit self-sustained retreat of the sector. For each basin, rates of contribution to sea-level rise are discussed together with the RCPs and time when tipping points could be reached and MISI triggered.

Dengue and climate change in Australia: predictions for the future should incorporate knowledge from the past.

PubMed

Russell, Richard C; Currie, Bart J; Lindsay, Michael D; Mackenzie, John S; Ritchie, Scott A; Whelan, Peter I

2009-03-02

Dengue transmission in Australia is currently restricted to Queensland, where the vector mosquito Aedes aegypti is established. Locally acquired infections have been reported only from urban areas in the north-east of the state, where the vector is most abundant. Considerable attention has been drawn to the potential impact of climate change on dengue distribution within Australia, with projections for substantial rises in incidence and distribution associated with increasing temperatures. However, historical data show that much of Australia has previously sustained both the vector mosquito and dengue viruses. Although current vector distribution is restricted to Queensland, the area inhabited by A. aegypti is larger than the disease-transmission areas, and is not restricted by temperature (or vector-control programs); thus, it is unlikely that rising temperatures alone will bring increased vector or virus distribution. Factors likely to be important to dengue and vector distribution in the future include increased dengue activity in Asian and Pacific nations that would raise rates of virus importation by travellers, importation of vectors via international ports to regions without A. aegypti, higher rates of domestic collection and storage of water that would provide habitat in urban areas, and growing human populations in northern Australia. Past and recent successful control initiatives in Australia lend support to the idea that well resourced and functioning surveillance programs, and effective public health intervention capabilities, are essential to counter threats from dengue and other mosquito-borne diseases. Models projecting future activity of dengue (or other vector-borne disease) with climate change should carefully consider the local historical and contemporary data on the ecology and distribution of the vector and local virus transmission.

Influence of infrasound exposure on the whole L-type calcium currents in rat ventricular myocytes.

PubMed

Pei, Zhaohui; Zhuang, Zhiqiang; Xiao, Pingxi; Chen, Jingzao; Sang, Hanfei; Ren, Jun; Wu, Zhenbiao; Yan, Guangmei

2009-06-01

This study was designed to examine the effect of infrasound exposure (5 Hz at 130 dB) on whole-cell L-type Ca2+ currents (WLCC) in rat ventricular myocytes and the underlying mechanism(s) involved. Thirty-two adult Sprague-Dawley rats were randomly assigned to infrasound exposure and control groups. [Ca2+](i), WLCC, mRNA expression of the a(1c) subunit of L-type Ca2+ channels (LCC), and SERCA2 protein were examined on day 1, 7, and 14 after initiation of infrasound exposure. Fluo-3/AM fluorescence and the laser scanning confocal microscope techniques were used to measure [Ca2+](i) in freshly isolated ventricular myocytes. The Ca2+ fluorescence intensity (FI), denoting [Ca2+](i) in cardiomyocytes, was significantly elevated in a time-dependent manner in the exposure groups. There was a significant increase in WLCC in the 1-day group and a further significant increase in the 7- and 14-day groups. LCC mRNA expression measured by RT-PCR revealed a significant rise in the 1-day group and a significant additional rise in the 7- and 14-day groups compared with control group. SERCA2 expression was significantly upregulated in the 1-day group followed by an overt decrease in the 7- and 14-day groups. Prolonged exposure of infrasound altered WLCC in rat cardiomyocytes by shifting the steady-state inactivation curves to the right (more depolarized direction) without altering the slope and biophysical properties of I (Ca,L). Taken together, our data suggest that changes in [Ca2+](I) levels as well as expression of LCC and SERCA2 may contribute to the infrasound exposure-elicited cardiac response.

Recent odour regulation developments in Flanders: ambient odour quality standards based on dose-response relationships.

PubMed

Van Broeck, G; Van Langenhove, H; Nieuwejaers, B

2001-01-01

Until now there has been little uniformity in the approach of odour nuisance problems in Flanders. A switch to a standardised and scientifically underpinned approach is essential and is currently in full development. This paper mainly discusses the results of five year research on odour concentration standard developments in Flanders, executed in the period 1996-2000. The research was focused on five pilot sectors: pig farms, slaughterhouses, paint spray installations, sewage treatment plants and textile plants. The general approach of the method to determine the dose-response relation was found to be sufficient. The methodology used is fully described in the paper presented by Van Broeck and Van Langenhove at the CIWEM and IAWO Joint International Conference on Control and Prevention of Odours in the Water Industry in September 1999. For each location (16 locations in total) an unambiguous dose-response relation could be derived (rising nuisance for rising concentrations). In most cases, a "no effect" level could be determined. The background percentage nuisance fluctuated between 0 and 15%. For the sectors of the slaughterhouses, paint spray installations and sewage treatment plants a no effect level was 0.5, 2.0 and 0.5 sniffing units m(-3) as 98th percentile (sniffing units are odour concentrations measured by means of sniffing measurements on the field) was determined. For the sectors of the textile plants and pig farms, no unambiguous no effect level was found. Currently research is undertaken to translate the no effect levels to odour standards. Other initiatives, taken to underpin the Flemish odour regulations, such as the development of an odour source inventory and a complaint handling system, are also briefly discussed.

Calcium-activated potassium channels in insect pacemaker neurons as unexpected target site for the novel fumigant dimethyl disulfide.

PubMed

Gautier, Hélène; Auger, Jacques; Legros, Christian; Lapied, Bruno

2008-01-01

Dimethyl disulfide (DMDS), a plant-derived insecticide, is a promising fumigant as a substitute for methyl bromide. To further understand the mode of action of DMDS, we examined its effect on cockroach octopaminergic neurosecretory cells, called dorsal unpaired median (DUM) neurons, using whole-cell patch-clamp technique, calcium imaging and antisense oligonucleotide strategy. At low concentration (1 microM), DMDS modified spontaneous regular spike discharge into clear bursting activity associated with a decrease of the amplitude of the afterhyperpolarization. This effect led us to suspect alterations of calcium-activated potassium currents (IKCa) and [Ca(2+)](i) changes. We showed that DMDS reduced amplitudes of both peak transient and sustained components of the total potassium current. IKCa was confirmed as a target of DMDS by using iberiotoxin, cadmium chloride, and pSlo antisense oligonucleotide. In addition, we showed that DMDS induced [Ca(2+)](i) rise in Fura-2-loaded DUM neurons. Using calcium-free solution, and (R,S)-(3,4-dihydro-6,7-dimethoxy-isoquinoline-1-yl)-2-phenyl-N,N-di-[2-(2,3,4-trimethoxy-phenyl)ethyl]-acetamide (LOE 908) [an inhibitor of transient receptor potential (TRP)gamma], we demonstrated that TRPgamma initiated calcium influx. By contrast, omega-conotoxin GVIA (an inhibitor of N-type high-voltage-activated calcium channels), did not affect the DMDS-induced [Ca(2+)](i) rise. Finally, the participation of the calcium-induced calcium release mechanism was investigated using thapsigargin, caffeine, and ryanodine. Our study revealed that DMDS-induced elevation in [Ca(2+)](i) modulated IKCa in an unexpected bell-shaped manner via intracellular calcium. In conclusion, DMDS affects multiple targets, which could be an effective way to improve pest control efficacy of fumigation.

A statistical model for combustion resonance from a DI diesel engine with applications

NASA Astrophysics Data System (ADS)

Bodisco, Timothy; Low Choy, Samantha; Masri, Assaad; Brown, Richard J.

2015-08-01

Introduced in this paper is a Bayesian model for isolating the resonant frequency from combustion chamber resonance. The model shown in this paper focused on characterising the initial rise in the resonant frequency to investigate the rise of in-cylinder bulk temperature associated with combustion. By resolving the model parameters, it is possible to determine: the start of pre-mixed combustion, the start of diffusion combustion, the initial resonant frequency, the resonant frequency as a function of crank angle, the in-cylinder bulk temperature as a function of crank angle and the trapped mass as a function of crank angle. The Bayesian method allows for individual cycles to be examined without cycle-averaging-allowing inter-cycle variability studies. Results are shown for a turbo-charged, common-rail compression ignition engine run at 2000 rpm and full load.

Ice2sea - the future glacial contribution to sea-level rise

NASA Astrophysics Data System (ADS)

Vaughan, D. G.; Ice2sea Consortium

2009-04-01

The melting of continental ice (glaciers, ice caps and ice sheets) is a substantial source of current sea-level rise, and one that is accelerating more rapidly than was predicted even a few years ago. Indeed, the most recent report from Intergovernmental Panel on Climate Change highlighted that the uncertainty in projections of future sea-level rise is dominated by uncertainty concerning continental ice, and that understanding of the key processes that will lead to loss of continental ice must be improved before reliable projections of sea-level rise can be produced. Such projections are urgently required for effective sea-defence management and coastal adaptation planning. Ice2sea is a consortium of European institutes and international partners seeking European funding to support an integrated scientific programme to improve understanding concerning the future glacial contribution to sea-level rise. This includes improving understanding of the processes that control, past, current and future sea-level rise, and generation of improved estimates of the contribution of glacial components to sea-level rise over the next 200 years. The programme will include targeted studies of key processes in mountain glacier systems and ice caps (e.g. Svalbard), and in ice sheets in both polar regions (Greenland and Antarctica) to improve understanding of how these systems will respond to future climate change. It will include fieldwork and remote sensing studies, and develop a suite of new, cross-validated glacier and ice-sheet model. Ice2sea will deliver these results in forms accessible to scientists, policy-makers and the general public, which will include clear presentations of the sources of uncertainty. Our aim is both, to provide improved projections of the glacial contribution to sea-level rise, and to leave a legacy of improved tools and techniques that will form the basis of ongoing refinements in sea-level projection. Ice2sea will provide exciting opportunities for many early-career glaciologists and ice-modellers in a variety of host institutes.

Individual differences in the cortisol-awakening response during the first two years of shift work: A longitudinal study in novice police officers.

PubMed

Lammers-van der Holst, Heidi M; Kerkhof, Gerard A

2015-01-01

Cortisol acts as a critical biological intermediary through which chronic stressors like shift work impact upon multiple physiological, neuro-endocrine and hormonal functions. Therefore, the cortisol awakening response (CAR) is suggested as a prime index of shift work tolerance. Repeated assessments of the CAR (calculated as MnInc) in a group of 25 young novice police officers showed that in the interval between about 4 and 14 months after transitioning from regular day work to rotating shift work, mean values began to rise from baseline to significantly higher levels at about 14 months after they commenced shift work. Visual inspection of the individual trends revealed that a subgroup of 10 subjects followed a monotonically rising trend, whereas another 14 subjects, after an initial rise from about 4-14 months, reverted to a smaller, baseline level cortisol response at about 20 months after the start of shift work. If the initial increase in the cortisol response marks the development of a chronic stress response, the subsequent reversal to baseline levels in the subgroup of 14 participants might be indicative of a process of recovery, possibly the development of shift work tolerance.

Pressurised electro-osmotic dewatering of activated and anaerobically digested sludges: electrical variables analysis.

PubMed

Citeau, M; Olivier, J; Mahmoud, A; Vaxelaire, J; Larue, O; Vorobiev, E

2012-09-15

Pressurised electro-osmotic dewatering (PEOD) of two sewage sludges (activated and anaerobically digested) was studied under constant electric current (C.C.) and constant voltage (C.V.) with a laboratory chamber simulating closely an industrial filter. The influence of sludge characteristics, process parameters, and electrode/filter cloth position was investigated. The next parameters were tested: 40 and 80 A/m², 20, 30, and 50 V-for digested sludge dewatering; and 20, 40 and 80 A/m², 20, 30, and 50 V-for activated sludge dewatering. Effects of filter cloth electric resistance and initial cake thickness were also investigated. The application of PEOD provides a gain of 12 points of dry solids content for the digested sludge (47.0% w/w) and for the activated sludge (31.7% w/w). In PEOD processed at C.C. or at C.V., the dewatering flow rate was similar for the same electric field intensity. In C.C. mode, both the electric resistance of cake and voltage increase, causing a temperature rise by ohmic effect. In C.V. mode, a current intensity peak was observed in the earlier dewatering period. Applying at first a constant current and later on a constant voltage, permitted to have better control of ohmic heating effect. The dewatering rate was not significantly affected by the presence of filter cloth on electrodes, but the use of a thin filter cloth reduced remarkably the energy consumption compared to a thicker one: 69% of reduction energy input at 45% w/w of dry solids content. The reduction of the initial cake thickness is advantageous to increase the final dry solids content. Copyright © 2012 Elsevier Ltd. All rights reserved.

BK potassium channels facilitate high-frequency firing and cause early spike frequency adaptation in rat CA1 hippocampal pyramidal cells

PubMed Central

Gu, Ning; Vervaeke, Koen; Storm, Johan F

2007-01-01

Neuronal potassium (K+) channels are usually regarded as largely inhibitory, i.e. reducing excitability. Here we show that BK-type calcium-activated K+ channels enhance high-frequency firing and cause early spike frequency adaptation in neurons. By combining slice electrophysiology and computational modelling, we investigated functions of BK channels in regulation of high-frequency firing in rat CA1 pyramidal cells. Blockade of BK channels by iberiotoxin (IbTX) selectively reduced the initial discharge frequency in response to strong depolarizing current injections, thus reducing the early spike frequency adaptation. IbTX also blocked the fast afterhyperpolarization (fAHP), slowed spike rise and decay, and elevated the spike threshold. Simulations with a computational model of a CA1 pyramidal cell confirmed that the BK channel-mediated rapid spike repolarization and fAHP limits activation of slower K+ channels (in particular the delayed rectifier potassium current (IDR)) and Na+ channel inactivation, whereas M-, sAHP- or SK-channels seem not to be important for the early facilitating effect. Since the BK current rapidly inactivates, its facilitating effect diminishes during the initial discharge, thus producing early spike frequency adaptation by an unconventional mechanism. This mechanism is highly frequency dependent. Thus, IbTX had virtually no effect at spike frequencies < 40 Hz. Furthermore, extracellular field recordings demonstrated (and model simulations supported) that BK channels contribute importantly to high-frequency burst firing in response to excitatory synaptic input to distal dendrites. These results strongly support the idea that BK channels play an important role for early high-frequency, rapidly adapting firing in hippocampal pyramidal neurons, thus promoting the type of bursting that is characteristic of these cells in vivo, during behaviour. PMID:17303637

Plasma Discharge Initiation of Explosives in Rock Blasting Application: A Case Study

NASA Astrophysics Data System (ADS)

Jae-Ou, Chae; Young-Jun, Jeong; V, M. Shmelev; A, A. Denicaev; V, M. Poutchkov; V, Ravi

2006-07-01

A plasma discharge initiation system for the explosive volumetric combustion charge was designed, investigated and developed for practical application. Laboratory scale experiments were carried out before conducting the large scale field tests. The resultant explosions gave rise to less noise, insignificant seismic vibrations and good specific explosive consumption for rock blasting. Importantly, the technique was found to be safe and environmentally friendly.

Eddy energy and shelf interactions in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Ohlmann, J. Carter; Niiler, P. Peter; Fox, Chad A.; Leben, Robert R.

2001-02-01

Sea surface height anomaly data from satellite are continuously available for the entire Gulf of Mexico. Surface current velocities derived from these remotely sensed data are compared with surface velocities from drifting buoys. The comparison shows that satellite altimetry does an excellent job resolving gulf eddies over the shelf rise (depths between ˜200 and 2000 m) if the proper length scale is used. Correlations between altimeter- and drifter-derived velocities are statistically significant (r>0.5) when the surface slope is computed over 125 km, indicating that remotely sensed sea surface height anomaly data can be used to aid the understanding of circulation over the shelf rise. Velocity variance over the shelf rise from the altimetry data shows regions of pronounced eddy energy south of the Mississippi outflow, south of the Texas-Louisiana shelf, and in the northwest and northeast corners of the gulf. These are the same locations where surface drifters are most likely to cross the shelf rise, suggesting gulf eddies promote cross-shore flows. This is clearly exemplified with both warm and cold eddies. Finally, the contribution of gulf eddies and wind stress to changes in the mean circulation are compared. Results indicate that the eddy-generated vorticity flux to the mean flow is greater than the contribution from the surface wind stress curl, especially in the region of the Loop current and along the shelf rise base in the western gulf. Future modeling efforts must not neglect the role of eddies in driving gulf circulation over the shelf rise.

Asymmetric Magnetic Reconnection in the Solar Atmosphere

NASA Astrophysics Data System (ADS)

Murphy, N. A.; Miralles, M. P.; Ranquist, D. A.; Pope, C. L.; Raymond, J. C.; Lukin, V. S.; McKillop, S.; Shen, C.; Winter, H. D.; Reeves, K. K.; Lin, J.

2013-12-01

Models of solar flares and coronal mass ejections typically predict the development of an elongated current sheet in the wake behind the rising flux rope. In reality, reconnection in these current sheets will be asymmetric along the inflow, outflow, and out-of-plane directions. We perform resistive MHD simulations to investigate the consequences of asymmetry during solar reconnection. We predict several observational signatures of asymmetric reconnection, including flare loops with a skewed candle flame shape, slow drifting of the current sheet into the strong field upstream region, asymmetric footpoint speeds and hard X-ray emission, and rolling motions within the erupting flux rope. There is net plasma flow across the magnetic field null along both the inflow and outflow directions. We compare simulations to SDO/AIA, Hinode/XRT, and STEREO observations of flare loop shapes, current sheet drifting, and rolling motions during prominence eruptions. Simulations of the plasmoid instability with different upstream magnetic fields show that the reconnection rate remains enhanced even during the asymmetric case. The islands preferentially grow into the weak field upstream region. The islands develop net vorticity because the outflow jets impact them obliquely rather than directly. Asymmetric reconnection in the chromosphere occurs when emerging flux interacts with pre-existing overlying flux. We present initial results on asymmetric reconnection in partially ionized chromospheric plasmas. Finally, we discuss how comparisons to observations are necessary to understand the role of three-dimensional effects.

Asymmetric Magnetic Reconnection in the Solar Atmosphere

NASA Astrophysics Data System (ADS)

Murphy, N. A.; Miralles, M. P.; Ranquist, D. A.; Pope, C. L.; Raymond, J. C.; Lukin, V. S.; McKillop, S. C.; Shen, C.; Winter, H. D.; Reeves, K. K.; Lin, J.

2013-12-01

Models of solar flares and coronal mass ejections typically predict the development of an elongated current sheet in the wake behind the rising flux rope. In reality, reconnection in these current sheets will be asymmetric along the inflow, outflow, and out-of-plane directions. We perform resistive MHD simulations to investigate the consequences of asymmetry during solar reconnection. We predict several observational signatures of asymmetric reconnection, including flare loops with a skewed candle flame shape, slow drifting of the current sheet into the strong field upstream region, asymmetric footpoint speeds and hard X-ray emission, and rolling motions within the erupting flux rope. There is net plasma flow across the magnetic field null along both the inflow and outflow directions. We compare simulations to SDO/AIA, Hinode/XRT, and STEREO observations of flare loop shapes, current sheet drifting, and rolling motions during prominence eruptions. Simulations of the plasm! oid instability with different upstream magnetic fields show that the reconnection rate remains enhanced even during the asymmetric case. The islands preferentially grow into the weak field upstream region. The islands develop net vorticity because the outflow jets impact them obliquely rather than directly. Asymmetric reconnection in the chromosphere occurs when emerging flux interacts with pre-existing overlying flux. We present initial results on asymmetric reconnection in partially ionized chromospheric plasmas. Finally, we discuss how comparisons to observations are necessary to understand the role of three-dimensional effects.

Low edge safety factor operation and passive disruption avoidance in current carrying plasmas by the addition of stellarator rotational transform

NASA Astrophysics Data System (ADS)

Pandya, M. D.; ArchMiller, M. C.; Cianciosa, M. R.; Ennis, D. A.; Hanson, J. D.; Hartwell, G. J.; Hebert, J. D.; Herfindal, J. L.; Knowlton, S. F.; Ma, X.; Massidda, S.; Maurer, D. A.; Roberds, N. A.; Traverso, P. J.

2015-11-01

Low edge safety factor operation at a value less than two ( q (a )=1 /ι̷tot(a )<2 ) is routine on the Compact Toroidal Hybrid device with the addition of sufficient external rotational transform. Presently, the operational space of this current carrying stellarator extends down to q (a )=1.2 without significant n = 1 kink mode activity after the initial plasma current rise phase of the discharge. The disruption dynamics of these low edge safety factor plasmas depend upon the fraction of helical field rotational transform from external stellarator coils to that generated by the plasma current. We observe that with approximately 10% of the total rotational transform supplied by the stellarator coils, low edge q disruptions are passively suppressed and avoided even though q(a) < 2. When the plasma does disrupt, the instability precursors measured and implicated as the cause are internal tearing modes with poloidal, m, and toroidal, n, helical mode numbers of m /n =3 /2 and 4/3 observed on external magnetic sensors and m /n =1 /1 activity observed on core soft x-ray emissivity measurements. Even though the edge safety factor passes through and becomes much less than q(a) < 2, external n = 1 kink mode activity does not appear to play a significant role in the disruption phenomenology observed.

The Plasma Wake Downstream of Lunar Topographic Obstacles: Preliminary Results from 2D Particle Simulations

NASA Technical Reports Server (NTRS)

Zimmerman, Michael I.; Farrell, W. M.; Snubbs, T. J.; Halekas, J. S.

2011-01-01

Anticipating the plasma and electrical environments in permanently shadowed regions (PSRs) of the moon is critical in understanding local processes of space weathering, surface charging, surface chemistry, volatile production and trapping, exo-ion sputtering, and charged dust transport. In the present study, we have employed the open-source XOOPIC code [I] to investigate the effects of solar wind conditions and plasma-surface interactions on the electrical environment in PSRs through fully two-dimensional pattic1e-in-cell simulations. By direct analogy with current understanding of the global lunar wake (e.g., references) deep, near-terminator, shadowed craters are expected to produce plasma "mini-wakes" just leeward of the crater wall. The present results (e.g., Figure I) are in agreement with previous claims that hot electrons rush into the crater void ahead of the heavier ions, fanning a negative cloud of charge. Charge separation along the initial plasma-vacuum interface gives rise to an ambipolar electric field that subsequently accelerates ions into the void. However, the situation is complicated by the presence of the dynamic lunar surface, which develops an electric potential in response to local plasma currents (e.g., Figure Ia). In some regimes, wake structure is clearly affected by the presence of the charged crater floor as it seeks to achieve current balance (i.e. zero net current to the surface).

Nondestructive test determines overload destruction characteristics of current limiter fuses

NASA Technical Reports Server (NTRS)

Swartz, G. A.

1968-01-01

Nondestructive test predicts the time required for current limiters to blow /open the circuit/ when subjected to a given overload. The test method is based on an empirical relationship between the voltage rise across a current limiter for a fixed time interval and the time to blow.

The contribution of cationic conductances to the potential of rod photoreceptors.

PubMed

Moriondo, Andrea; Rispoli, Giorgio

2010-05-01

The contribution of cationic conductances in shaping the rod photovoltage was studied in light adapted cells recorded under whole-cell voltage- or current-clamp conditions. Depolarising current steps (of size comparable to the light-regulated current) produced monotonic responses when the prepulse holding potential (V (h)) was -40 mV (i.e. corresponding to the membrane potential in the dark). At V (h) = -60 mV (simulating the steady-state response to an intense background of light) current injections <35 pA (mimicking a light decrement) produced instead an initial depolarisation that declined to a plateau, and voltage transiently overshot V (h) at the stimulus offset. Current steps >40 pA produced a steady depolarisation to approximately -16 mV at both V (h). The difference between the responses at the two V (h) was primarily generated by the slow delayed-rectifier-like K(+) current (I (Kx)), which therefore strongly affects both the photoresponse rising and falling phase. The steady voltage observed at both V (h) in response to large current injections was instead generated by Ca-activated K(+) channels (I (KCa)), as previously found. Both I (Kx) and I (KCa) oppose the cation influx, occurring at the light stimulus offset through the cGMP-gated channels and the voltage-activated Ca(2+) channels (I (Ca)). This avoids that the cation influx could erratically depolarise the rod past its normal resting value, thus allowing a reliable dim stimuli detection, without slowing down the photovoltage recovery kinetics. The latter kinetics was instead accelerated by the hyperpolarisation-activated, non-selective current (I (h)) and I (Ca). Blockade of all K(+) currents with external TEA unmasked a I (Ca)-dependent regenerative behaviour.

Adjustable direct current and pulsed circuit fault current limiter

DOEpatents

Boenig, Heinrich J.; Schillig, Josef B.

2003-09-23

A fault current limiting system for direct current circuits and for pulsed power circuit. In the circuits, a current source biases a diode that is in series with the circuits' transmission line. If fault current in a circuit exceeds current from the current source biasing the diode open, the diode will cease conducting and route the fault current through the current source and an inductor. This limits the rate of rise and the peak value of the fault current.

Influence of emission threshold of explosive emission cathodes on current waveform in foilless diodes

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

Wu, P.; Liu, G. Z.; Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024

The emission threshold of explosive emission cathodes (EECs) is an important factor for beam quality. It can affect the explosive emission delay time, the plasma expansion process on the cathode surface, and even the current amplitude when the current is not fully space-charge-limited. This paper researches the influence of the emission threshold of an annular EEC on the current waveform in a foilless diode when the current is measured by a Rogowski coil. The particle-in-cell simulation which is performed under some tolerable and necessary simplifications shows that the long explosive emission delay time of high-threshold cathodes may leave an apparentmore » peak of displacement current on the rise edge of the current waveform, and this will occur only when the electron emission starts after this peak. The experimental researches, which are performed under a diode voltage of 1 MV and a repetitive frequency of 20 Hz, demonstrate that the graphite cathode has a lower emission threshold and a longer lifetime than the stainless steel cathode according to the variation of the peak of displacement current on the rise edge of the current waveform.« less

The contribution to future flood risk in the Severn Estuary from extreme sea level rise due to ice sheet mass loss

NASA Astrophysics Data System (ADS)

Quinn, N.; Bates, P. D.; Siddall, M.

2013-12-01

The rate at which sea levels will rise in the coming century is of great interest to decision makers tasked with developing mitigation policies to cope with the risk of coastal inundation. Accurate estimates of future sea levels are vital in the provision of effective policy. Recent reports from UK Climate Impacts Programme (UKCIP) suggest that mean sea levels in the UK may rise by as much as 80 cm by 2100; however, a great deal of uncertainty surrounds model predictions, particularly the contribution from ice sheets responding to climatic warming. For this reason, the application of semi-empirical modelling approaches for sea level rise predictions has increased of late, the results from which suggest that the rate of sea level rise may be greater than previously thought, exceeding 1 m by 2100. Furthermore, studies in the Red Sea indicate that rapid sea level rise beyond 1m per century has occurred in the past. In light of such research, the latest UKCIP assessment has included a H++ scenario for sea level rise in the UK of up to 1.9 m which is defined as improbable but, crucially, physically plausible. The significance of such low-probability sea level rise scenarios upon the estimation of future flood risk is assessed using the Somerset levels (UK) as a case study. A simple asymmetric probability distribution is constructed to include sea level rise scenarios of up to 1.9 m by 2100 which are added to a current 1:200 year event water level to force a two-dimensional hydrodynamic model of coastal inundation. From the resulting ensemble predictions an estimation of risk by 2100 is established. The results indicate that although the likelihood of extreme sea level rise due to rapid ice sheet mass loss is low, the resulting hazard can be large, resulting in a significant (27%) increase to the projected annual risk. Furthermore, current defence construction guidelines for the coming century in the UK are expected to account for 95% of the sea level rise distribution presented in this research, while the larger, low probability scenarios beyond this level are estimated to contribute a residual annual risk of approximately £0.45 million. These findings clearly demonstrate that uncertainty in future sea level rise is a vital component of coastal flood risk, and therefore, needs to be accounted for by decision makers when considering mitigation policies related to coastal flooding.

White Paper: Summary of the NOAA Workshop - Ecological Effect of Sea Level Rise in the Florida Panhandle and Coastal Alabama: Research and Modeling Needs

EPA Science Inventory

The Center for Sponsored Coastal Ocean Research (CSCOR) is addressing current and future impacts to ecological systems due to the long term effect of sea level rise due to climate change and subsidence on coastal ecosystems through the peer-reviewed research program, the Ecologic...

Analytical chemical kinetic investigation of the effects of oxygen, hydrogen, and hydroxyl radicals on hydrogen-air combustion

NASA Technical Reports Server (NTRS)

Carson, G. T., Jr.

1974-01-01

Quantitative values were computed which show the effects of the presence of small amounts of oxygen, hydrogen, and hydroxyl radicals on the finite-rate chemical kinetics of premixed hydrogen-air mixtures undergoing isobaric autoignition and combustion. The free radicals were considered to be initially present in hydrogen-air mixtures at equivalence ratios of 0.2, 0.6, 1.0, and 1.2. Initial mixture temperatures were 1100 K, 1200 K, and 1500 K, and pressures were 0.5, 1.0, 2.0, and 4.0 atm. Of the radicals investigated, atomic oxygen was found to be the most effective for reducing induction time, defined as the time to 5 percent of the total combustion temperature rise. The reaction time, the time between 5 percent and 95 percent of the temperature rise, is not decreased by the presence of free radicals in the initial hydrogen-air mixture. Fuel additives which yield free radicals might be used to effect a compact supersonic combustor design for efficient operation in an otherwise reaction-limited combustion regime.

ISMIP6 - initMIP: Greenland ice sheet model initialisation experiments

NASA Astrophysics Data System (ADS)

Goelzer, Heiko; Nowicki, Sophie; Payne, Tony; Larour, Eric; Abe Ouchi, Ayako; Gregory, Jonathan; Lipscomb, William; Seroussi, Helene; Shepherd, Andrew; Edwards, Tamsin

2016-04-01

Earlier large-scale Greenland ice sheet sea-level projections e.g. those run during ice2sea and SeaRISE initiatives have shown that ice sheet initialisation can have a large effect on the projections and gives rise to important uncertainties. This intercomparison exercise (initMIP) aims at comparing, evaluating and improving the initialization techniques used in the ice sheet modeling community and to estimate the associated uncertainties. It is the first in a series of ice sheet model intercomparison activities within ISMIP6 (Ice Sheet Model Intercomparison Project for CMIP6). The experiments are conceived for the large-scale Greenland ice sheet and are designed to allow intercomparison between participating models of 1) the initial present-day state of the ice sheet and 2) the response in two schematic forward experiments. The latter experiments serve to evaluate the initialisation in terms of model drift (forward run without any forcing) and response to a large perturbation (prescribed surface mass balance anomaly). We present and discuss first results of the intercomparison and highlight important uncertainties with respect to projections of the Greenland ice sheet sea-level contribution.

Standardising Responsibility? The Significance of Interstitial Spaces.

PubMed

Wickson, Fern; Forsberg, Ellen-Marie

2015-10-01

Modern society is characterised by rapid technological development that is often socially controversial and plagued by extensive scientific uncertainty concerning its socio-ecological impacts. Within this context, the concept of 'responsible research and innovation' (RRI) is currently rising to prominence in international discourse concerning science and technology governance. As this emerging concept of RRI begins to be enacted through instruments, approaches, and initiatives, it is valuable to explore what it is coming to mean for and in practice. In this paper we draw attention to a realm that is often backgrounded in the current discussions of RRI but which has a highly significant impact on scientific research, innovation and policy-namely, the interstitial space of international standardization. Drawing on the case of nanoscale sciences and technologies to make our argument, we present examples of how international standards are already entangled in the development of RRI and yet, how the process of international standardization itself largely fails to embody the norms proposed as characterizing RRI. We suggest that although current models for RRI provide a promising attempt to make research and innovation more responsive to societal needs, ethical values and environmental challenges, such approaches will need to encompass and address a greater diversity of innovation system agents and spaces if they are to prove successful in their aims.

Nonuniformity of carrier injection and the degradation of blue LEDs

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

Bochkareva, N. I.; Efremov, A. A.; Rebane, Yu. T.

The distribution of electroluminescence (EL) intensity over the area and in the course of time before and after the optical degradation of blue InGaN/GaN LEDs is studied. Current-voltage characteristics have been recorded. It is found that the initially bright luminescence near the region of metallization of the p-contact turns weak after the degradation of an LED. The time delay of {approx}20-40 ns is observed in the distribution of EL intensity over the area of LEDs after their degradation. We suppose that a rise in the excess current after degradation is due to the density increasing of the InGaN/GaN interface statesmore » and the formation of an electrical dipole, which lowers the potential barriers in p-GaN and n-GaN layers. The corresponding increase of capacitance leads to a time delay in the spreading of the injection current and in the distribution of the emission brightness over the area. The lateral nonuniformity of the carrier injection into the quantum, well before and after optical degradation, is attributed to diffusion and electromigration of hydrogen, induced by mechanical stress. The metallization of the p-contact may be the source of mechanical stress.« less

Fuel magnetization without external field coils (AutoMag)

NASA Astrophysics Data System (ADS)

Slutz, Stephen; Jennings, Christopher; Awe, Thomas; Shipley, Gabe; Lamppa, Derek; McBride, Ryan

2016-10-01

Magnetized Liner Inertial Fusion (MagLIF) has produced fusion-relevant plasma conditions on the Z accelerator where the fuel was magnetized using external field coils. We present a novel concept that does not need external field coils. This concept (AutoMag) magnetizes the fuel during the early part of the drive current by using a composite liner with helical conduction paths separated by insulating material. The drive is designed so the current rises slowly enough to avoid electrical breakdown of the insulators until a sufficiently strong magnetic field is established. Then the current rises more quickly, which causes the insulators to break down allowing the drive current to follow an axial path and implode the liner. Low inductance magnetically insulated power feeds can be used with AutoMag to increase the drive current without interfering with diagnostic access. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

AlGaN/GaN-on-Si monolithic power-switching device with integrated gate current booster

NASA Astrophysics Data System (ADS)

Han, Sang-Woo; Jo, Min-Gi; Kim, Hyungtak; Cho, Chun-Hyung; Cha, Ho-Young

2017-08-01

This study investigates the effects of a monolithic gate current booster integrated with an AlGaN/GaN-on-Si power-switching device. The integrated gate current booster was implemented by a single-stage inverter topology consisting of a recessed normally-off AlGaN/GaN MOS-HFET and a mesa resistor. The monolithically integrated gate current booster in a switching FET eliminated the parasitic elements caused by external interconnection and enabled fast switching operation. The gate charging and discharging currents were boosted by the integrated inverter, which significantly reduced both rise and fall times: the rise time was reduced from 626 to 41.26 ns, while the fall time was reduced from 554 to 42.19 ns by the single-stage inverter. When the packaged monolithic power chip was tested under 1 MHz hard-switching operation with VDD = 200 V, the switching loss was found to have been drastically reduced, from 5.27 to 0.55 W.

Sensitivity of Hurricane Storm Surge to Land Cover and Topography Under Various Sea Level Rise Scenarios Along the Mississippi Coast

NASA Astrophysics Data System (ADS)

Bilskie, M. V.; Hagen, S. C.; Medeiros, S. C.

2013-12-01

Major Gulf hurricanes have a high probability of impacting the northern Gulf of Mexico, especially coastal Mississippi (Resio, 2007). Due to the wide and flat continental shelf, this area provides near-perfect geometry for high water levels under tropical cyclone conditions. Literature suggests with 'very high confidence that global sea level will rise at least 0.2 m and no more than 2.0 m by 2011' (Donoghue, 2011; Parris et al., 2012). Further, it is recognized that the Mississippi barrier islands are highly susceptible to a westward migration and retreating shoreline. With predictions for less frequent, more intense tropical storms, rising sea levels, and a changing landscape, it is important to understand how these changes may affect inundation extent and flooding due to hurricane storm surge. A state-of-the-art SWAN+ADCIRC hydrodynamic model of coastal Mississippi was utilized to simulate Hurricane Katrina with present day sea level conditions. Using present day as a base scenario, past (1960) and future (2050) sea level changes were simulated. In addition to altering the initial sea state, land use land cover (LULC) was modified for 1960 and 2050 based on historic data and future projections. LULC datasets are used to derive surface roughness characteristics, such as Manning's n, and wind reduction factors. The topography along the barrier islands and near the Pascagoula River, MS was also altered to reflect the 1960 landscape. Storm surge sensitivity to topographic change were addressed by comparing model results between two 1960 storm surge simulations; one with current topography and a second with changes to the barrier islands. In addition, model responses to changes in LULC are compared. The results will be used to gain insight into adapting present day storm surge models for future conditions. References Donoghue, J. (2011). Sea level history of the northern Gulf of Mexico coast and sea level rise scenarios for the near future. Climatic Change, 107(1-2), 17-33. doi: 10.1007/s10584-011-0077-x Parris, A., Bromirski, P., Burkett, V., Cayan, D., Culver, M., Hall, J., . . . Weiss, J. (2012). Global Sea Level Rise Scenarios for the United States National Climate Assessment NOAA Tech Memo OAR CPO-1 (pp. 37). Resio, D. T. (2007). White paper on estimating hurricane inundation probabilities (pp. 125). Vicksburg, MS: U.S. Army Engineering Research and Development Center.

Efficacy of emamectin benzoate against sea lice infestations of Atlantic salmon, Salmo salar L.: evaluation in the absence of an untreated contemporary control.

PubMed

Gustafson, L; Ellis, S; Robinson, T; Marenghi, F; Endris, R

2006-10-01

The efficacy of emamectin benzoate (SLICE) against sea lice infestations of Atlantic salmon, Salmo salar L., is typically assessed using untreated fish, or fish treated with alternative therapeutants, as controls. The State of Maine, USA, is currently under active management for the OIE-notifiable pathogen, infectious salmon anaemia virus (ISAV); consequently, neither control group is feasible in this region. Untreated salmon risk extensive damage from the ectoparasites, and threaten to increase vector-borne exposure or susceptibility of farms to ISAV; and the only treatment presently available in Maine is SLICE. However, because sea lice infestations are unlikely to resolve spontaneously, and response to treatment occurs within weeks, use of a pretreatment baseline is a reasonable alternative for confirmatory studies. We evaluated SLICE efficacy on Atlantic salmon farms in Cobscook Bay 2002-2005, in the absence of untreated controls, using pretreatment lice loads as a reference for calculation. Maximum efficacy ranged from 68% to 100% reduction from initial levels. Time-to-maximum efficacy ranged from 1 to 8 weeks after treatment initiation. Efficacy duration, measured between first reduction and first progressive rise in counts, ranged from 4 to 16 weeks.

Forced convection in the wakes of impacting and sliding bubbles

NASA Astrophysics Data System (ADS)

O'Reilly Meehan, R.; Williams, N. P.; Donnelly, B.; Persoons, T.; Nolan, K.; Murray, D. B.

2017-09-01

Both vapour and gas bubbles are known to significantly increase heat transfer rates between a heated surface and the surrounding fluid, even with no phase change. The cooling structures observed are highly temporal, intricate and complex, with a full description of the surface cooling phenomena not yet available. The current study uses high speed infrared thermography to measure the surface temperature and determine the convective heat flux enhancement associated with the interaction of a single air bubble with a heated, inclined surface. This process can be discretised into the initial impact, in which enhancement levels in excess of 20 times natural convection are observed, and the subsequent sliding behaviour, with more moderate maximum enhancement levels of 8 times natural convection. In both cases, localised regions of suppressed heat transfer are also observed due to the recirculation of warm fluid displaced from the thermal boundary layer with the surface. The cooling patterns observed herein are consistent with the interaction between an undulating wake containing multiple hairpin vortex loops and the thermal boundary layer that exists under the surface, with the initial nature of this enhancement and suppression dependent on the particular point on its rising path at which the bubble impacts the surface.

Decent Work: A Psychological Perspective

PubMed Central

Blustein, David L.; Olle, Chad; Connors-Kellgren, Alice; Diamonti, A. J.

2016-01-01

This contribution, which serves as the lead article for the Research Topic entitled “From Meaning of Working to Meaningful Lives: The Challenges of Expanding Decent Work,” explores current challenges in the development and operationalization of decent work. Based on an initiative from the International Labor Organization [ILO] (1999) decent work represents an aspirational statement about the quality of work that should be available to all people who seek to work around the globe. Within recent years, several critiques have been raised about decent work from various disciplines, highlighting concerns about a retreat from the social justice ethos that had initially defined the concept. In addition, other scholars have observed that decent work has not included a focus on the role of meaning and purpose at work. To address these concerns, we propose that a psychological perspective can help to revitalize the decent work agenda by infusing a more specific focus on individual experiences and by reconnecting decent work to its social justice origins. As an illustration of the advantages of a psychological perspective, we explore the rise of precarious work and also connect the decent work agenda to the Psychology-of-Working Framework and Theory (Blustein, 2006; Duffy et al., 2016). PMID:27047430

Quantitative three-dimensional transrectal ultrasound (TRUS) for prostate imaging

NASA Astrophysics Data System (ADS)

Pathak, Sayan D.; Aarnink, Rene G.; de la Rosette, Jean J.; Chalana, Vikram; Wijkstra, Hessel; Haynor, David R.; Debruyne, Frans M. J.; Kim, Yongmin

1998-06-01

With the number of men seeking medical care for prostate diseases rising steadily, the need of a fast and accurate prostate boundary detection and volume estimation tool is being increasingly experienced by the clinicians. Currently, these measurements are made manually, which results in a large examination time. A possible solution is to improve the efficiency by automating the boundary detection and volume estimation process with minimal involvement from the human experts. In this paper, we present an algorithm based on SNAKES to detect the boundaries. Our approach is to selectively enhance the contrast along the edges using an algorithm called sticks and integrate it with a SNAKES model. This integrated algorithm requires an initial curve for each ultrasound image to initiate the boundary detection process. We have used different schemes to generate the curves with a varying degree of automation and evaluated its effects on the algorithm performance. After the boundaries are identified, the prostate volume is calculated using planimetric volumetry. We have tested our algorithm on 6 different prostate volumes and compared the performance against the volumes manually measured by 3 experts. With the increase in the user inputs, the algorithm performance improved as expected. The results demonstrate that given an initial contour reasonably close to the prostate boundaries, the algorithm successfully delineates the prostate boundaries in an image, and the resulting volume measurements are in close agreement with those made by the human experts.

Thulium fibre laser nerve stimulation and its application in human pain research

NASA Astrophysics Data System (ADS)

Warnaby, Catherine E.

Experimental pain induction, in combination with psychophysical and functional imaging techniques, allows the controlled study of the mechanisms, pathways and brain areas involved in the processing of noxious stimuli. Laser nerve stimulation provides an excellent stimulus that selectively activates the Adelta and C nociceptors with only low concurrent activity in the warmth system. Thulium fibre laser systems, operating near 2mum, offer several advantages over other pain stimulators including the CO[2] and Tm:YAG laser systems. These advantages include direct absorption at the location of the nociceptors, reduced likelihood of tissue damage, improved compatibility with fMRI, and wavelength tunability. The main aims of the thesis were to apply an initial thulium fibre laser system to pain activation studies in healthy subjects and confirm the potential advantages. A 1D finite difference photothermal model confirmed that thulium fibre laser radiation is absorbed throughout the expected location of the nociceptors and produces a lower surface temperature than CO[2] radiation. In order to produce a temperature rise of 9°C at 150mum, thulium radiation induces a surface temperature rise of 12°C compared to 21°C surface temperature rise using CO[2] radiation. The use of thulium fibre radiation greatly reduces the likelihood of tissue damage and first-degree burns when compared to CO[2] radiation. The spatial temperature gradient and the surface temperature rise were also found to be strongly dependent on the thulium fibre laser emission wavelength, which implies that wavelength tuning may be used to obtain the optimum stimulus wavelength in the 2mum region. The 5W initial fibre laser system was fully characterised before application to human pain studies and was shown to have excellent reproducibility of the stimulus parameters, with short-term and long-term deviations of the pulse energy of 5% and 8% of the mean respectively. The thulium fibre laser emits radiation over a 38nm wavelength range from 2.006-2.044mum. The initial system was used successfully to elicit painful sensations and laser evoked potentials (LEPs), which showed the expected dependence on the laser stimulus parameters. In agreement with the modelled results, beam diameters from 5-8mm for a 150ms pulse duration were found to elicit painful responses while minimising tissue damage. Psychophysical assessment of the pain threshold energy and energy density in ten volunteers, using the modified staircase technique and the method of constant stimuli, also showed the expected dependence on the laser beam diameter over this range. The topographical distribution of the LEPs elicited by the thulium fibre laser and a CO[2] pain stimulator were found to be very similar. However, statistically significant differences in the peak latencies of the LEP components were observed. The peak latency of the N2, P2 and P3 components elicited by the thulium fibre laser were found to be longer by 44ms, 52ms and 78ms respectively than those elicited by the CO[2] laser across five volunteers. These latency differences are believed to be due to the difference in beam diameter of the two stimuli, which produces an increase in local spatial summation for the CO[2] laser stimuli. The effectiveness of the thulium fibre laser as a controlled pain stimulator for human pain research has been confirmed. Using the current thulium fibre laser stimulation system, the optimum stimulus parameters are provided by a beam diameter of 6mm and a pulse duration of 150ms. However, further application of the current system to human pain research is limited by the available output power and the delivery of the thulium radiation to the subject. Suggestions are made for further work using an improved thulium fibre laser system with an increased output power of 20W, optical fibre delivery and wavelength tuning.

Health care prices, the federal budget, and economic growth.

PubMed

Monaco, R M; Phelps, J H

1995-01-01

Rising health care spending, led by rising prices, has had an enormous impact on the economy, especially on the federal budget. Our work shows that if rapid growth in health care prices continues, under current institutional arrangements, real economic growth and employment will be lower during the next two decades than if health price inflation were somehow reduced. How big the losses are and which sectors bear the brunt of the costs vary depending on how society chooses to fund the federal budget deficit that stems from the rising cost of federal health care programs.

Ionospheric modification - An initial report on artificially created equatorial Spread F

NASA Technical Reports Server (NTRS)

Ossakow, S. L.; Zalesak, S. T.; Mcdonald, B. E.

1978-01-01

A numerical simulation code for investigating equatorial Spread F in the collisional Rayleigh-Taylor regime is utilized to follow the evolution of artificial plasma density depletions injected into the bottomside nighttime equatorial F region. The 70 km diameter hole rapidly rises and steepens, forming plasma density enhancements at altitudes below the rising hole. The distribution of enhancements and depletions is similar to natural equatorial Spread F phenomena, except it occurs on a much faster time scale. These predictions warrant carrying out artificial injection experiments in the nighttime equatorial F region.

Seventh-day syndrome: a catastrophic event after liver transplantation: case report.

PubMed

Pereira, M; Ferreira, I; Gandara, J; Ferreira, S; Lopes, V; Coelho, A; Vizcaino, R; Marinho, A; Daniel, J; Miranda, H P

2015-05-01

Seventh-day syndrome (7DS) is an early serious complication of liver transplantation, characterized by sudden failure of a previously normally functioning liver graft ∼1 week after the surgery. Although it is an uncommon event, it has major associated mortality. As its etiology is yet to be recognized, the only currently available treatment is retransplantation. We present 3 cases of orthotopic liver transplantation recipients who had an initial uneventful recovery after surgery followed by a dramatic rise of serum liver enzyme levels ∼7 days later and hepatic failure with subsequent graft loss and death despite high-dose immunosuppressive therapy. Histologic findings showed massive centrolobular hemorrhage and hepatocellular necrosis with reduced inflammation. It is essential to review and accumulate more clinical and laboratory information to better understand this syndrome and to better prevent and treat it. Copyright © 2015 Elsevier Inc. All rights reserved.

[Functional respiratory evolution in two patients with emphysema and pulmonary fibrosis].

PubMed

Arce, Santiago C; Molinari, Luciana; De Vito, Eduardo L

2009-01-01

Combined pulmonary fibrosis and emphysema (CPFE) is a frequently under-diagnosed condition. Isolated pulmonary function tests (PFT) can give rise to misinterpretations. We have found no reports on these patients' spirometric progression. We describe two cases of CPFE, showing long-term functional evolution to have a more accurate understanding of current spirometric values. The most relevant findings are: 1) spirometry with discrete functional alterations in the presence of a marked dyspnea and the need, in one patient, for chronic oxygen therapy; and 2) functional evolution reflecting "pseudonormalisation" of the initial obstructive spirometric pattern, possibly as a result of fibrosis development. A mild obstructive defect in a patient with chronic airflow limitation and marked impairment of his/her clinical status and functional class should alert on the possibility of associated pulmonary fibrosis. A computed tomography (CT) and previous PFTs will allow a better understanding of this condition.

Using biological effects tools to define Good Environmental Status under the European Union Marine Strategy Framework Directive.

PubMed

Lyons, B P; Thain, J E; Stentiford, G D; Hylland, K; Davies, I M; Vethaak, A D

2010-10-01

The use of biological effects tools offer enormous potential to meet the challenges outlined by the European Union Marine Strategy Framework Directive (MSFD) whereby Member States are required to develop a robust set of tools for defining 11 qualitative descriptors of Good Environmental Status (GES), such as demonstrating that "Concentrations of contaminants are at levels not giving rise to pollution effects" (GES Descriptor 8). This paper discusses the combined approach of monitoring chemical contaminant levels, along side biological effect measurements relating to the effect of pollutants, for undertaking assessments of GES across European marine regions. We outline the minimum standards that biological effects tools should meet if they are to be used for defining GES in relation to Descriptor 8 and describe the current international initiatives underway to develop assessment criteria for these biological effects techniques. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Sexual revolution in China: implications for Chinese women and society.

PubMed

Xiao, Zhiwen; Mehrotra, Purnima; Zimmerman, Rick

2011-06-01

China is undergoing rapid changes in sexual mores due to several reasons such as decreasing control of the state over private lives of individuals, globalization of its economy, and some policies initiated by the state. There is increased acceptance of premarital sex and extramarital sex in China, especially among youth. In historically conservative China, influenced by Confucian ideals of patriarchal dominance for centuries, the sexual freedom currently enjoyed by many is unprecedented. This has impacted women's status and sexual lives in several positive ways such as increasing freedom of sexual expression, control over their bodies, sexual choices, and increasing equality with men in all spheres of life. However several negative consequences such as a rise in STD/HIV prevalence, commercial sex, and divorce rates have also been attributed to the ongoing sexual revolution in China. Recommendations combating these and suggestions for directions in future research are discussed.

Natural enemies govern ecosystem resilience in the face of extreme droughts.

PubMed

He, Qiang; Silliman, Brian R; Liu, Zezheng; Cui, Baoshan

2017-02-01

Severe droughts are on the rise in many regions. But thus far, attempts to predict when drought will cause a major regime shift or when ecosystems are resilient, often using plant drought tolerance models, have been frustrated. Here, we show that pressure from natural enemies regulates an ecosystem's resilience to severe droughts. Field experiments revealed that in protected salt marshes experiencing a severe drought, plant-eating grazers eliminated drought-stressed vegetation that could otherwise survive and recover from the climate extreme, transforming once lush marshes into persistent salt barrens. These results provide an explicit experimental demonstration for the obligatory role of natural enemies across the initiation, expansion and recovery stages of a natural ecosystem's collapse. Our study highlights that natural enemies can hasten an ecosystem's resilience to drought to much lower levels than currently predicted, calling for integration into climate change predictions and conservation strategies. © 2017 John Wiley & Sons Ltd/CNRS.

[A place of intravenous immunoglobulins in current clinical practice: Privigen is a novel 10% immunoglobulin].

PubMed

Latysheva, T V; Latysheva, E A; Martynova, I A

2016-01-01

Intravenous immunoglobulins (IVIGs) were initially designed to treat patients with primary immunodeficiencies (PID). Due to the multidirectional effect of IVIGs on the immune system, a range of nosological entities, in which these agents are successfully administered, is steadily expanding. As of now, IVIGs are successfully used in neurology, rheumatology, hematology, and oncology and they are essential drugs for many patients. In spite of the long experience with IVIGs, their mechanism of action remains unclear, numerous investigations for their clinical introduction are being continued. Therefore, there is a growing need to increase the production of the drugs, which gives rise to the emergence of novel medications, which differ in their composition and manufacture technologies, on the pharmacological market. The 10% intravenous immunoglobulin privigen, the safety and efficacy of which has been proven in foreign practice, is a novel drug on the Russian market.

NASCAP modelling of high-voltage power system interactions with space charged-particle environments

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Roche, J. C.; Mandell, M. J.

1979-01-01

A simple space power system operating in geosynchronous orbit was analyzed. This system consisted of two solar array wings and a central body. Each solar array wing was considered to be divided into three regions operating at 2000 volts. The center body was considered to be an electrical ground with the array voltages both positive and negative relative to ground. The system was analyzed for both a normal environment and a moderate geomagnetic substorm environment. Initial results indicate a high probability of arcing at the interconnects on the negative operating voltage wing. The dielectric strength of the substrate may be exceeded giving rise to breakdown in the bulk of the material. The geomagnetic substorm did not seem to increase the electrical gradients at the interconnects on the negative operating voltage wing but did increase the gradients on the positive operating voltage wing which could result in increased coupling current losses.

Sedimentation from particle-bearing plumes in a stratified ambient

NASA Astrophysics Data System (ADS)

Sutherland, Bruce R.; Hong, Youn Sub Dominic

2016-11-01

Laboratory experiments are performed to examine the sedimentation of particles that initially rise in a plume, then spread radially and settle in uniformly stratified fluid. Using light attenuation, the depth of the sediment bed is measured nonintrusively as a function of radius from the center of the plume. To gain some insight into these dynamics, an idealized model is developed by adapting well-established plume theory and a theory that accounts for sedimentation from surface gravity currents emanating from a plume impacting a rigid lid. We also account for recycling of falling particles that are re-entrained into the plume. With a suitable choice of parameters determining the intrusion height, entrainment during fountain collapse, and the radius at which settling from the intrusion begins, in most cases for which particles are predicted to be drawn back into the plume and recycled. The predictions for intrusion height, particle mound height, and spread agree within 20% of observations.

Coral mass spawning predicted by rapid seasonal rise in ocean temperature

PubMed Central

Maynard, Jeffrey A.; Edwards, Alasdair J.; Guest, James R.; Rahbek, Carsten

2016-01-01

Coral spawning times have been linked to multiple environmental factors; however, to what extent these factors act as generalized cues across multiple species and large spatial scales is unknown. We used a unique dataset of coral spawning from 34 reefs in the Indian and Pacific Oceans to test if month of spawning and peak spawning month in assemblages of Acropora spp. can be predicted by sea surface temperature (SST), photosynthetically available radiation, wind speed, current speed, rainfall or sunset time. Contrary to the classic view that high mean SST initiates coral spawning, we found rapid increases in SST to be the best predictor in both cases (month of spawning: R2 = 0.73, peak: R2 = 0.62). Our findings suggest that a rapid increase in SST provides the dominant proximate cue for coral mass spawning over large geographical scales. We hypothesize that coral spawning is ultimately timed to ensure optimal fertilization success. PMID:27170709

900 Numbers: A Controversial Industry.

ERIC Educational Resources Information Center

Galvez, Nancy D.

1992-01-01

Pay-per-call telephone services through 900 numbers have given rise to criticism of their content and complaints of consumer fraud. The Federal Communications Commission, legislative initiatives, industry self-regulation, and consumer educators are attempting to protect consumers. (SK)

Yeast respond to hypotonic shock with a calcium pulse

NASA Technical Reports Server (NTRS)

Batiza, A. F.; Schulz, T.; Masson, P. H.

1996-01-01

We have used the transgenic AEQUORIN calcium reporter system to monitor the cytosolic calcium ([Ca2+]cyt) response of Saccharomyces cerevisiae to hypotonic shock. Such a shock generates an almost immediate and transient rise in [Ca2+]cyt which is eliminated by gadolinium, a blocker of stretch-activated channels. In addition, this transient rise in [Ca2+]cyt is initially insensitive to 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), an extracellular calcium chelator. However, BAPTA abruptly attenuates the maintenance of that transient rise. These data show that hypotonic shock generates a stretch-activated channel-dependent calcium pulse in yeast. They also suggest that the immediate calcium influx is primarily generated from intracellular stores, and that a sustained increase in [Ca2+]cyt depends upon extracellular calcium.

Effect of degrading yellow oxo-biodegradable low-density polyethylene films to water quality

NASA Astrophysics Data System (ADS)

Requejo, B. A.; Pajarito, B. B.

2017-05-01

Polyethylene (PE) contributes largely to plastic wastes that are disposed in aquatic environment as a consequence of its widespread use. In this study, yellow oxo-biodegradable low-density PE films were immersed in deionized water at 50°C for 49 days. Indicators of water quality: pH, oxidation-reduction potential, turbidity, and total dissolved solids (TDS), were monitored at regular intervals. It was observed that pH initially rises and then slowly decreases with time, oxidation-reduction potential decreases then slowly increases with time, turbidity rises above the control at varied rates, and TDS increases abruptly and rises at a hindered rate. Moreover, the films potentially leach out lead chromate. The results imply that degrading oxo-biodegradable LDPE films results to significant reduction of water quality.

The intonation of gapping and coordination in Japanese: evidence for intonational phrase and utterance.

PubMed

Kawahara, Shigeto; Shinya, Takahito

2008-01-01

In previous studies of Japanese intonational phonology, levels of prosodic constituents above the Major Phrase have not received much attention. This paper argues that at least two prosodic levels exist above the Major Phrase in Japanese. Through a detailed investigation of the intonation of gapping and coordination in Japanese, we argue that each syntactic clause projects its own Intonational Phrase, while an entire sentence constitutes one Utterance. We show that the Intonational Phrase is characterized by tonal lowering, creakiness and a pause in final position, as well as a distinctive large initial rise and pitch reset at its beginning. The Utterance defines a domain of declination, and it is signaled by an even larger initial rise, as well as a phrasal H tone at its right edge. Building on our empirical findings, we discuss several implications for the theory of intonational phonology. (c) 2007 S. Karger AG, Basel.

Alcohols potentiate the function of 5-HT3 receptor–channels on NCB-20 neuroblastoma cells by favouring and stabilizing the open channel state

PubMed Central

Zhou, Qing; Verdoorn, Todd A; Lovinger, David M

1998-01-01

5-HT3 receptor-mediated ion current was recorded from NCB-20 neuroblastoma cells using the whole-cell patch-clamp technique. Rapid drug superfusion was used to study the mechanism of alcohol potentiation of 5-HT3 receptor function and to analyse effects of alcohols on receptor-channel kinetics in detail.Trichloroethanol (TCEt) increased in a dose-dependent way the initial slope, 20–80 % rise time and measured desensitization rate of the current induced by low concentrations (1–2 μm) of 5-HT. Ethanol (EtOH) and butanol (ButOH) had similar effects on the 5-HT3 receptor-induced current.TCEt and ButOH decreased the measured desensitization rate of current induced by 10 μm 5-HT, a maximally effective concentration of agonist. These alcohols also increased the relative amplitude of steady state to peak current induced by 2 or 10 μm 5-HT, indicating a possible decrease in the intrinsic rate of desensitization.TCEt also decreased the deactivation rate of the current activated by 2 μm 5-HT after a short pulse of agonist application.Current sweeps generated by 1 μm 5-HT in the presence or absence of 10 mm TCEt or 100 mm EtOH were well fitted using a modified standard kinetic model derived from the nicotinic acetylcholine receptor. This analysis indicated that potentiation by alcohols could be accounted for by increases in the association rate constant coupled with decreases in the dissociation and desensitization rate constants.This study suggests that alcohols potentiate 5-HT3 receptor-mediated current by both increasing the rate of channel activation and stabilizing the open state by decreasing the rates of channel deactivation and desensitization. PMID:9518697

Urban Shanty Town Recognition Based on High-Resolution Remote Sensing Images and National Geographical Monitoring Features - a Case Study of Nanning City

NASA Astrophysics Data System (ADS)

He, Y.; He, Y.

2018-04-01

Urban shanty towns are communities that has contiguous old and dilapidated houses with more than 2000 square meters built-up area or more than 50 households. This study makes attempts to extract shanty towns in Nanning City using the product of Census and TripleSat satellite images. With 0.8-meter high-resolution remote sensing images, five texture characteristics (energy, contrast, maximum probability, and inverse difference moment) of shanty towns are trained and analyzed through GLCM. In this study, samples of shanty town are well classified with 98.2 % producer accuracy of unsupervised classification and 73.2 % supervised classification correctness. Low-rise and mid-rise residential blocks in Nanning City are classified into 4 different types by using k-means clustering and nearest neighbour classification respectively. This study initially establish texture feature descriptions of different types of residential areas, especially low-rise and mid-rise buildings, which would help city administrator evaluate residential blocks and reconstruction shanty towns.

Insulin resistance in the control of body fat distribution: a new hypothesis.

PubMed

Ali, A T; Ferris, W F; Naran, N H; Crowther, N J

2011-02-01

Obesity causes insulin resistance, which is a prime etiological factor for type 2 diabetes, dyslipidemia, and cardiovascular disease. However, insulin resistance may be a normal physiological response to obesity that limits further fat deposition and which only has pathological effects at high levels. The current hypothesis suggests that in obesity the initial deposition of triglycerides occurs in subcutaneous adipose tissue and as this increases in size insulin resistance will rise and limit further subcutaneous lipid accumulation. Triglycerides will then be diverted to the visceral fat depot as well as to ectopic sites. This leads to a substantial rise in insulin resistance and the prevalence of its associated disorders. Evidence supporting this hypothesis includes studies showing that in lean subjects the prime determinant of insulin resistance is BMI, that is, subcutaneous fat whilst in overweight and obese subjects it is waist circumference and visceral adiposity. It has also been shown that the metabolic syndrome suddenly increases in prevalence at high levels of insulin resistance and we suggest that this is due to the diversion of lipids from the subcutaneous to the visceral depot. This system may have functioned in our evolutionary past to limit excessive adiposity by causing lipid deposition to occur at a site that has maximal effects on insulin resistance but involves minimal weight gain. © Georg Thieme Verlag KG Stuttgart · New York.

A comparative analysis of potential impact area of common sugar cane burning methods

NASA Astrophysics Data System (ADS)

Hiscox, A. L.; Flecher, S.; Wang, J. J.; Viator, H. P.

2015-04-01

The negative effects of agricultural burning are well-known, although the actual impact area of different activities has not previously been quantified. An elastic backscatter lidar system was used to examine the impact-area size and dispersion of smoke generated from different types of sugarcane burning activities; pre-harvest (standing) burning and post-harvest (ground) burning. Experiments were conducted in the sugarcane harvest season of 2010 and 2011 at two locations in Louisiana, USA. Current dispersion theory would suggest that the primary difference between burn types would be primarily in the initial plume rise, but that the overall plume shape would remain the same. However, remotely sensed lidar data with the capability to measure plume dispersion and the short time dynamics of plume location showed pre-harvest (standing) burning produced a larger plume with greater rise and more spread within the 300 m of the plume, but a decrease in dispersion, but not concentration further downwind. Post-harvest (ground) burning produced a more traditional plume shape, but still exceeded impact area predictions near the source. Moreover, large changes in plume size can occur with small increases in wind speed. These are the first instrumented measurements of the meteorological effects of the different types of sugarcane burning. These results indicate that ground burning is preferable, but should be avoided in lower wind speed conditions.

Characteristics code for shock initiation

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

Partom, Y.

1986-10-01

We developed SHIN, a characteristics code for shock initiation studies. We describe in detail the equations of state, reaction model, rate equations, and numerical difference equations that SHIN incorporates. SHIN uses the previously developed surface burning reaction model which better represents the shock initiation process in TATB, than do bulk reaction models. A large number of computed simulations prove the code is a reliable and efficient tool for shock initiation studies. A parametric study shows the effect on build-up and run distance to detonation of (1) type of boundary condtion, (2) burning velocity curve, (3) shock duration, (4) rise timemore » in ramp loading, (5) initial density (or porosity) of the explosive, (6) initial temperature, and (7) grain size. 29 refs., 65 figs.« less

Marshes to mudflats—Effects of sea-level rise on tidal marshes along a latitudinal gradient in the Pacific Northwest

USGS Publications Warehouse

Thorne, Karen M.; Dugger, Bruce D.; Buffington, Kevin J.; Freeman, Chase M.; Janousek, Christopher N.; Powelson, Katherine W.; Gutenspergen, Glenn R.; Takekawa, John Y.

2015-11-17

In the Pacific Northwest, coastal wetlands support a wealth of ecosystem services including habitat provision for wildlife and fisheries and flood protection. The tidal marshes, mudflats, and shallow bays of coastal estuaries link marine, freshwater, and terrestrial habitats, and provide economic and recreational benefits to local communities. Climate change effects such as sea-level rise are altering these habitats, but we know little about how these areas will change over the next 50–100 years. Our study examined the effects of sea-level rise on nine tidal marshes in Washington and Oregon between 2012 and 2015, with the goal of providing scientific data to support future coastal planning and conservation. We compiled physical and biological data, including coastal topography, tidal inundation, vegetation structure, as well as recent and historical sediment accretion rates, to assess and model how sea-level rise may alter these ecosystems in the future. Multiple factors, including initial elevation, marsh productivity, sediment availability, and rates of sea-level rise, affected marsh persistence. Under a low sea-level rise scenario, all marshes remained vegetated with little change in the present configuration of communities of marsh plants or gradually increased proportions of middle-, high-, or transition-elevation zones of marsh vegetation. However, at most sites, mid sea-level rise projections led to loss of habitat of middle and high marshes and a gain of low marshes. Under a high sea-level rise scenario, marshes at most sites eventually converted to intertidal mudflats. Two sites (Grays Harbor and Willapa) seemed to have the most resilience to a high rate of rise in sea-level, persisting as low marsh until at least 2110. Our main model finding is that most tidal marsh study sites are resilient to sea-level rise over the next 50–70 years, but that sea-level rise will eventually outpace marsh accretion and drown most habitats of high and middle marshes by 2110.

Global climate change and sea level rise: potential losses of intertidal habitat for shorebirds

Treesearch

H. Galbraith; R. Jones; R. Park; J. Clough; S. Herrod-Julius; B. Harrington; G. Page

2005-01-01

Global warming is expected to result in an acceleration of current rates of sea level rise, inundating many low-lying coastal and intertidal areas. This could have important implications for organisms that depend on these sites, including shorebirds that rely on them for foraging habitat during their migrations and in winter. We modeled the potential changes in the...

8 Different approaches needed to manage ED demand among different age-groups.

PubMed

Rimmer, Melanie; Ablard, Suzanne; O'Keeffe, Colin; Mason, Suzanne

2017-12-01

A variety of interventions have been proposed to manage rising demand for Emergency and Urgent Care, described by an NHS England review as unsustainable in the long term. However it is unlikely that any suggested approach will be equally suitable for the diverse population of ED users.We aimed to understand the patterns of demand amongst different types of patients attending ED. We also sought to understand the intended and unintended effects of demand management initiatives. Our study combined insights from routine data, a survey of ED patients, and qualitative interviews with ED staff. This paper describes the results of our analysis of the interviews. We conducted semi-structured interviews with 25 ED and Urgent Care Centre staff across 7 hospital sites in Yorkshire and Humber between 25 April and 11 July 2016. The interview topic guide asked about 4 broad areas; job role, description of patients and their impact on demand, description of inappropriate attendance, and current/future initiatives to deal with rising demand. Interviews were transcribed verbatim and analysed using framework analysis. We analysed the results to identify groups of patients with different patterns of use of ED services. We also explored ED staff experiences of demand management initiatives, and their suggestions for future initiatives. Although we did not ask specifically about patients' age, our analysis revealed that ED staff categorised attenders as children and young people, working age people, and older people. These groups had different reasons for attendance, different routes to the ED, different rate of non-urgent attendance, and different issues driving demand. Staff also described variation in the time taken to treat patients of different ages, with the oldest and youngest patients described as requiring the most time.There was no consensus amongst staff about the effectiveness of initiatives for managing demand. A strikingly wide variety of initiatives were mentioned including patient education, co-location of other services with ED ('ED hubs'), and extending community-based services. ED staff attribute distinctly different patterns of ED attendance to patients of different age groups, including reasons for attending ED, the route to the ED, and the rate of non-urgent attendance. Given this variation, proposed demand management interventions are likely to impact differently on different age groups, and one solution is unlikely to be optimal for all ages. Therefore a number of different approaches will be needed to manage ED demand among different age groups. © 2017, Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Experimental investigation on the energy deposition and expansion rate under the electrical explosion of aluminum wire in vacuum

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

Shi, Zongqian; Wang, Kun; Shi, Yuanjie

Experimental investigations on the electrical explosion of aluminum wire using negative polarity current in vacuum are presented. Current pulses with rise rates of 40 A/ns, 80 A/ns, and 120 A/ns are generated for investigating the influence of current rise rate on energy deposition. Experimental results show a significant increase of energy deposition into the wire before the voltage breakdown with the increase of current rise rate. The influence of wire dimension on energy deposition is investigated as well. Decreasing the wire length allows more energy to be deposited into the wire. The energy deposition of a 0.5 cm-long wire explosion ismore » ∼2.5 times higher than the energy deposition of a 2 cm-long wire explosion. The dependence of the energy deposition on wire diameter demonstrates a maximum energy deposition of 2.7 eV/atom with a diameter of ∼18 μm. Substantial increase in energy deposition is observed in the electrical explosion of aluminum wire with polyimide coating. A laser probe is applied to construct the shadowgraphy, schlieren, and interferometry diagnostics. The morphology and expansion trajectory of exploding products are analyzed based on the shadowgram. The interference phase shift is reconstructed from the interferogram. Parallel dual wires are exploded to estimate the expansion velocity of the plasma shell.« less

Modeling Anthropogenic Impact on Sediment Balance and Relative Sea-Level Rise in Contemporary and Future Deltas

NASA Astrophysics Data System (ADS)

Tessler, Z. D.; Vorosmarty, C. J.; Overeem, I.; Syvitski, J. P.

2017-12-01

Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning, and affect the long-term sustainability of these landscapes for both human and natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea-level rise across 46 global deltas. We model ongoing development and scenarios of future water resource management and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea-level in coastal delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea-level rise result in relative sea-level rise rates in deltas that average 6.8 mm/year. Currently planned or under-construction dams can be expected to increase rates of relative sea-level rise on the order of 1 mm/year. Some deltas systems, including the Magdalena, Orinoco, and Indus, are highly sensitive to future impoundment of river basins, with RSLR rates increasing up to 4 mm/year in a high-hydropower-utilization scenario. Sediment fluxes may be reduced by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Megnha if all currently planned dams are constructed. Reduced sediment retention on deltas due to increased river channelization and local flood controls increases RSLR on average by nearly 2 mm/year. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea-level rise.

Consistent Initial Conditions for the DNS of Compressible Turbulence

NASA Technical Reports Server (NTRS)

Ristorcelli, J. R.; Blaisdell, G. A.

1996-01-01

Relationships between diverse thermodynamic quantities appropriate to weakly compressible turbulence are derived. It is shown that for turbulence of a finite turbulent Mach number there is a finite element of compressibility. A methodology for generating initial conditions for the fluctuating pressure, density and dilatational velocity is given which is consistent with finite Mach number effects. Use of these initial conditions gives rise to a smooth development of the flow, in contrast to cases in which these fields are specified arbitrarily or set to zero. Comparisons of the effect of different types of initial conditions are made using direct numerical simulation of decaying isotropic turbulence.

Ca2+-induced Ca2+ Release Phenomena in Mammalian Sympathetic Neurons Are Critically Dependent on the Rate of Rise of Trigger Ca2+

PubMed Central

Hernández-Cruz, Arturo; Escobar, Ariel L.; Jiménez, Nicolás

1997-01-01

The role of ryanodine-sensitive intracellular Ca2+ stores present in nonmuscular cells is not yet completely understood. Here we examine the physiological parameters determining the dynamics of caffeine-induced Ca2+ release in individual fura-2–loaded sympathetic neurons. Two ryanodine-sensitive release components were distinguished: an early, transient release (TR) and a delayed, persistent release (PR). The TR component shows refractoriness, depends on the filling status of the store, and requires caffeine concentrations ≥10 mM. Furthermore, it is selectively suppressed by tetracaine and intracellular BAPTA, which interfere with Ca2+-mediated feedback loops, suggesting that it constitutes a Ca2+-induced Ca2+-release phenomenon. The dynamics of release is markedly affected when Sr2+ substitutes for Ca2+, indicating that Sr2+ release may operate with lower feedback gain than Ca2+ release. Our data indicate that when the initial release occurs at an adequately fast rate, Ca2+ triggers further release, producing a regenerative response, which is interrupted by depletion of releasable Ca2+ and Ca2+-dependent inactivation. A compartmentalized linear diffusion model can reproduce caffeine responses: When the Ca2+ reservoir is full, the rapid initial Ca2+ rise determines a faster occupation of the ryanodine receptor Ca2+ activation site giving rise to a regenerative release. With the store only partially loaded, the slower initial Ca2+ rise allows the inactivating site of the release channel to become occupied nearly as quickly as the activating site, thereby suppressing the initial fast release. The PR component is less dependent on the store's Ca2+ content. This study suggests that transmembrane Ca2+ influx in rat sympathetic neurons does not evoke widespread amplification by CICR because of its inability to raise [Ca2+] near the Ca2+ release channels sufficiently fast to overcome their Ca2+-dependent inactivation. Conversely, caffeine-induced Ca2+ release can undergo considerable amplification especially when Ca2+ stores are full. We propose that the primary function of ryanodine-sensitive stores in neurons and perhaps in other nonmuscular cells, is to emphasize subcellular Ca2+ gradients resulting from agonist-induced intracellular release. The amplification gain is dependent both on the agonist concentration and on the filling status of intracellular Ca2+ stores. PMID:9041445

Emergent properties of magnetic materials

NASA Astrophysics Data System (ADS)

Ratcliff, William Davis, II

In Tolstoy's War and Peace, history is presented as a tapestry spun from the daily interactions of large numbers of individuals. Even if one understands individuals, it is very difficult to predict history. Similarly, the interactions of large numbers of electrons give rise to properties that one would not initially guess from their microscopic interactions. During the course of my dissertation, I have explored emergent phenomena in a number of contexts. In ZnCr2O4, geometric frustration gives rise to a plethora of equivalent ground states. From these, a lower dimensional set of collinear spins on hexagons are selected to form the building blocks of the lattice. In MgTi2O4, quantum spins dimerize and form a unique chiral ordering pattern on the spinel lattice. Descending into two dimensions, differences in size and charge give rise to an ordering between triangular layers of magnetic and nonmagnetic ions. This triangular lattice allows for the possibility of observing the RVB spin liquid state, or perhaps a valence bond crystal and initial measurements are promising. Also, on the spinel lattice, ionic ordering gives rise to one dimensional chains with their own interesting physics. Finally, in the SrCoxTi1-x O3, system we find that upon reduction, tiny clusters of Co metal precipitate out and chemical inhomogeneity on the microscale may determine much of the physics. This has relevance to a number of recent claims of room temperature ferromagnism in dilute magnetic systems. In all of these systems, complex behavior emerges from well understood microscopic behavior. For me, this is the fascination of strongly correlated electronic systems.

Higher Incidence Rates of Hypothyroidism and Late TSH Rise in Preterm Very-Low-Birth-Weight Infants at a Tertiary Care Center.

PubMed

Tfayli, Hala; Charafeddine, Lama; Tamim, Hani; Saade, Joanne; Daher, Rose T; Yunis, Khalid

2018-04-11

Preterm newborns with a very low birth weight (VLBW) of < 1,500 g have an atypical form of hypothyroidism with a delayed rise in TSH, necessitating a second newborn screening specimen collection. The aims of this study were to survey the compliance with second newborn screening to detect delayed TSH rise in VLBW preterm infants at a tertiary care center, and to determine the rate of atypical hypothyroidism. Retrospective review of the records of 104 preterm VLBW infants. Late TSH rise was defined as an increase in TSH concentration after 14 days of age in the presence of a normal initial screen. The compliance rate was 92% for the second screening. High rates of hypothyroidism (16.3%) and of late TSH rise (4.8%) were detected. Patients with hypothyroidism had a significantly lower birth weight (p = 0.01) and longer hospital stay (p = 0.004). Patients with late versus those with early TSH rise had a significantly lower mean birth weight (851 ± 302 vs. 1,191 ± 121 g, p = 0.004). The rates of early and late TSH rise in this VLBW population were higher than those in the literature and could be due to the use of povidone-iodine disinfectants. The yield of a second TSH screening in this study was high indicating the need for vigilance in screening VLBW preterm infants. © 2018 S. Karger AG, Basel.

Influence of Voltage Rise Time for Oxidation Treatment of NO in Simulated Exhausted Gas by Polarity-Reversed Pulse Discharge

NASA Astrophysics Data System (ADS)

Shinmoto, Kazuya; Kadowaki, Kazunori; Nishimoto, Sakae; Kitani, Isamu

This paper describes experimental study on NO removal from a simulated exhausted-gas using repetitive surface discharge on a glass barrier subjected to polarity-reversed voltage pulses. The very fast polarity-reversal with a rise time of 20ns is caused by direct grounding of a charged coaxial cable of 10m in length. Influence of voltage rise time on energy efficiency for NO removal is studied. Results of NO removal using a barrier-type plasma reactor with screw-plane electrode system indicates that the energy efficiency for the very fast polarity reversal caused by direct grounding becomes higher than that for the slower polarity reversal caused by grounding through an inductor at the cable end. The energy efficiency for the direct grounding is about 80g/kWh for 50% NO removal ratio and is about 60g/kWh for 100% NO removal ratio. Very intense discharge light is observed at the initial time of 10ns for the fast polarity reversal, whereas the intensity in the initial discharge light for the slower polarity reversal is relatively small. To confirm the effectiveness of the polarity-reversed pulse application, comparison of the energy efficiency between the polarity-reversed voltage pulse and ac 60Hz voltage will be presented.

Formation and Initiation of Erupting Flux Rope and Embedded Filament Driven by Photospheric Converging Motion

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

Zhao Xiaozhou; Gan, Weiqun; Xia, Chun

2017-06-01

In this paper, we study how a flux rope (FR) is formed and evolves into the corresponding structure of a coronal mass ejection (CME) numerically driven by photospheric converging motion. A two-and-a-half-dimensional magnetohydrodynamics simulation is conducted in a chromosphere-transition-corona setup. The initial arcade-like linear force-free magnetic field is driven by an imposed slow motion converging toward the magnetic inversion line at the bottom boundary. The convergence brings opposite-polarity magnetic flux to the polarity inversion, giving rise to the formation of an FR by magnetic reconnection and eventually to the eruption of a CME. During the FR formation, an embedded prominencemore » gets formed by the levitation of chromospheric material. We confirm that the converging flow is a potential mechanism for the formation of FRs and a possible triggering mechanism for CMEs. We investigate the thermal, dynamical, and magnetic properties of the FR and its embedded prominence by tracking their thermal evolution, analyzing their force balance, and measuring their kinematic quantities. The phase transition from the initiation phase to the acceleration phase of the kinematic evolution of the FR was observed in our simulation. The FR undergoes a series of quasi-static equilibrium states in the initiation phase; while in the acceleration phase the FR is driven by Lorentz force and the impulsive acceleration occurs. The underlying physical reason for the phase transition is the change of the reconnection mechanism from the Sweet–Parker to the unsteady bursty regime of reconnection in the evolving current sheet underneath the FR.« less

Impacts of seawater rise on seawater intrusion in the Nile Delta Aquifer, Egypt.

PubMed

Sefelnasr, Ahmed; Sherif, Mohsen

2014-01-01

Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain geometry. Such effects become more evident in flat, low land, coastal alluvial plans where large areas might be submerged with seawater under a relatively small increase in the seawater level. None of the studies combined the effect of increased groundwater pumping, due to the possible decline in precipitation and shortage in surface water resources, with the expected landward shift of the shore line. In this article, the possible effects of seawater level rise in the Mediterranean Sea on the seawater intrusion problem in the Nile Delta Aquifer are investigated using FEFLOW. The simulations are conducted in horizontal view while considering the effect of the shoreline landward shift using digital elevation models. In addition to the basic run (current conditions), six different scenarios are considered. Scenarios one, two, and three assume a 0.5 m seawater rise while the total pumping is reduced by 50%, maintained as per the current conditions and doubled, respectively. Scenarios four, five, and six assume a 1.0 m seawater rise and the total pumping is changed as in the first three scenarios. The shoreline is moved to account for the seawater rise and hence the study domain and the seaside boundary are modified accordingly. It is concluded that, large areas in the coastal zone of the Nile Delta will be submerged by seawater and the coast line will shift landward by several kilometers in the eastern and western sides of the Delta. Scenario six represents the worst case under which the volume of freshwater will be reduced to about 513 km(3) (billion m(3) ). © 2013, National Ground Water Association.

How does relativity affect magnetically induced currents?

PubMed

Berger, R J F; Repisky, M; Komorovsky, S

2015-09-21

Magnetically induced probability currents in molecules are studied in relativistic theory. Spin-orbit coupling (SOC) enhances the curvature and gives rise to a previously unobserved current cusp in AuH or small bulge-like distortions in HgH2 at the proton positions. The origin of this curvature is magnetically induced spin-density arising from SOC in the relativistic description.

Experimental evaluation of rigor mortis. VIII. Estimation of time since death by repeated measurements of the intensity of rigor mortis on rats.

PubMed

Krompecher, T

1994-10-21

The development of the intensity of rigor mortis was monitored in nine groups of rats. The measurements were initiated after 2, 4, 5, 6, 8, 12, 15, 24, and 48 h post mortem (p.m.) and lasted 5-9 h, which ideally should correspond to the usual procedure after the discovery of a corpse. The experiments were carried out at an ambient temperature of 24 degrees C. Measurements initiated early after death resulted in curves with a rising portion, a plateau, and a descending slope. Delaying the initial measurement translated into shorter rising portions, and curves initiated 8 h p.m. or later are comprised of a plateau and/or a downward slope only. Three different phases were observed suggesting simple rules that can help estimate the time since death: (1) if an increase in intensity was found, the initial measurements were conducted not later than 5 h p.m.; (2) if only a decrease in intensity was observed, the initial measurements were conducted not earlier than 7 h p.m.; and (3) at 24 h p.m., the resolution is complete, and no further changes in intensity should occur. Our results clearly demonstrate that repeated measurements of the intensity of rigor mortis allow a more accurate estimation of the time since death of the experimental animals than the single measurement method used earlier. A critical review of the literature on the estimation of time since death on the basis of objective measurements of the intensity of rigor mortis is also presented.

The Late Pleistocene Contourites on Ceara Rise: Stratigraphy, Sedimentology and Paleoceanography

NASA Astrophysics Data System (ADS)

Ivanova, E. V.; Murdmaa, I.; Borisov, D.; Seitkalieva, E.; Ovsepyan, E.

2016-12-01

The study of sediment cores obtained during the cruises 35 (2012) and 50 (2015) of RV Akademic Ioffe from the Ceara Rise in the western tropical Atlantic strongly supports a significant influence of bottom (contour) currents on the Late Quaternary sedimentation. Seismic evidence of contourites in the study area (migrating contourite sediment waves, furrows) was previously described by Kumar and Embley (1977) and Curry et al. (1995). Widespread distribution of seismic waves on the rise and adjacent areas was suggested by Murdmaa et al (2014) based on the results of high-resolution seismic profiling with SES-2000 deep (4-5 kHz) in 2012. Our sediment cores recovered intercalation of bioturbated clays and silty clays with thin linear or wavy sand and silt layers and lenses implying strong bottom current control on sedimentation. The stratigraphic frame of the reference core AI-3426 retrieved near the summit of the Ceara Rise, at the water depth of 3046 m is based on the foraminiferal (Globorotalia menardii zones), oxygen isotope and AMS-14C data. The core recovered sediments of the last 140 ka with very rich and well-preserved tropical planktic foraminiferal assemblages. G. menardii is common within MIS 1 and 5 and is almost absent in MIS 2-4 and upper MIS 6. The abundance of benthic foraminifers is rather low. However, dominance of Globocassidulina subglobosa in benthic assemblages likely indicates a moderate bottom-current activity on the Ceara Rise during the last glacial. The other 4-5m long sediment cores collected along the seismic profile from the northern and southern slopes demonstrate the similar contourite sedimentological features and insignificant reworking of the Neogene foraminiferal species as inferred from the core AI-3426 along with the significant variations in foraminiferal preservation during the Pleistocene. The study is supported by the projects RSF 14-50-00095, RFBR 14-05-00744 and RFBR 16-35-60111, and Program I3P by RAS.

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge

NASA Astrophysics Data System (ADS)

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge.

PubMed

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

Large-Scale Survey of the Structure of the Dayside Magnetopause by MMS

NASA Astrophysics Data System (ADS)

Paschmann, G.; Haaland, S. E.; Phan, T. D.; Sonnerup, B. U. Ö.; Burch, J. L.; Torbert, R. B.; Gershman, D. J.; Dorelli, J. C.; Giles, B. L.; Pollock, C.; Saito, Y.; Lavraud, B.; Russell, C. T.; Strangeway, R. J.; Baumjohann, W.; Fuselier, S. A.

2018-03-01

This paper describes the generation and initial utilization of a database containing 80 vector and scalar quantities, for a total of 8,670 magnetopause and magnetosheath current sheet crossings by MMS1, using plasma and magnetic field data from the Fast Plasma Investigation, Fluxgate Magnetometer, and Hot Plasma Composition Analyzer instruments, augmented by solar wind and interplanetary magnetic field data from CDAWeb. Based on a determination of the current sheet width, measured and calculated vector and scalar quantities are stored for the two sides of the current sheet and for selected times within the current sheet. The only manual operations were the classification of the current sheets according to the type of boundary, the character of the magnetic field transition, and the quality of the current sheet fit. To characterize the database, histograms of selected key quantities are presented. We then give the statistics for the duration, motion, and thicknesses of the magnetopause current sheet, using single-spacecraft techniques for the determination of the normal velocities, obtaining median results of 12.9 s, 38.5 km/s, and 705.4 km, respectively. When scaled to the ion inertial length, the median thickness became 12.6; there were no thicknesses less than one. Next, we apply the Walén relation to find crossings that are rotational discontinuities and thus may indicate ongoing magnetic reconnection. For crossings where the velocities in the outflow region exceed the velocity on the magnetosheath side by at least 250 km/s, 47% meet our rotational discontinuity criteria. If we require the outflow to exceed 250 km/s along the L direction, then the percentage rises to 68%.

High-rise construction as a method for architectural development of megapolises

NASA Astrophysics Data System (ADS)

Kankhva, Vadim

2018-03-01

The article analyzes the current state of urban development in Moscow, there are revealed the insights into pattern of large investment projects. The regulatory framework as well as the state and the forecast of housing funds are scrutinized. A number of problems, that are related to the implementation of high-rise construction projects at all stages of the life cycles, are highlighted by the example of unique facilities, which are under construction or have already been built. Substantiation of high-rise construction by the transport hubs in megapolises is given. There are also considered main advantages of Moscow renovation project and criticism against it.

Glaciers dominate eustatic sea-level rise in the 21st century

USGS Publications Warehouse

Meier, Mark Frederick; Dyurgerov, M.B.; Rick, Ursula K.; Pfeffer, William Tad; Anderson, Suzanne P.; Glazovsky, Andrey F.

2007-01-01

Ice loss to the sea currently accounts for virtually all of the sea-level rise that is not attributable to ocean warming, and about 60% of the ice loss is from glaciers and ice caps rather than from the two ice sheets. The contribution of these smaller glaciers has accelerated over the past decade, in part due to marked thinning and retreat of marine-terminating glaciers associated with a dynamic instability that is generally not considered in mass-balance and climate modeling. This acceleration of glacier melt may cause 0.1 to 0.25 meter of additional sea-level rise by 2100.

Adjoint assimilation of altimetric, surface drifter, and hydrographic data in a quasi-geostrophic model of the Azores Current

NASA Astrophysics Data System (ADS)

Morrow, Rosemary; de Mey, Pierre

1995-12-01

The flow characteristics in the region of the Azores Current are investigated by assimilating TOPEX/POSEIDON and ERS 1 altimeter data into the multilevel Harvard quasigeostrophic (QG) model with open boundaries (Miller et al., 1983) using an adjoint variational scheme (Moore, 1991). The study site lies in the path of the Azores Current, where a branch retroflects to the south in the vicinity of the Madeira Rise. The region was the site of an intensive field program in 1993, SEMAPHORE. We had two main aims in this adjoint assimilation project. The first was to see whether the adjoint method could be applied locally to optimize an initial guess field, derived from the continous assimilation of altimetry data using optimal interpolation (OI). The second aim was to assimilate a variety of different data sets and evaluate their importance in constraining our QG model. The adjoint assimilation of surface data was effective in optimizing the initial conditions from OI. After 20 iterations the cost function was generally reduced by 50-80%, depending on the chosen data constraints. The primary adjustment process was via the barotropic mode. Altimetry proved to be a good constraint on the variable flow field, in particular, for constraining the barotropic field. The excellent data quality of the TOPEX/POSEIDON (T/P) altimeter data provided smooth and reliable forcing; but for our mesoscale study in a region of long decorrelation times O(30 days), the spatial coverage from the combined T/P and ERS 1 data sets was more important for constraining the solution and providing stable flow at all levels. Surface drifters provided an excellent constraint on both the barotropic and baroclinic model fields. More importantly, the drifters provided a reliable measure of the mean field. Hydrographic data were also applied as a constraint; in general, hydrography provided a weak but effective constraint on the vertical Rossby modes in the model. Finally, forecasts run over a 2-month period indicate that the initial conditions optimized by the 20-day adjoint assimilation provide more stable, longer-term forecasts.

SafeTrip 21 initiative : networked traveler foresighted driving field experiment, final report.

DOT National Transportation Integrated Search

2011-04-01

The Networked Traveler Project was originally conceived to leverage the explosive rise of smartphones as a : communications gateway to bring real-time traveler assistance concepts from the ITS community to the American : people. The Networked Travele...

The Sun in a Drawer

ERIC Educational Resources Information Center

Anderson, Bruce

1975-01-01

Widespread use of solar energy is unsuccessful with large scale integration required and conservatism of responsible institutions. Rising fuel costs and government promotion may initiate expansion in commercial, environmental, and government establishments, homes, and schools. Difficulties encountered include financing, tax incentives, design,…

3 CFR 8746 - Proclamation 8746 of November 1, 2011. National Diabetes Month, 2011

Code of Federal Regulations, 2012 CFR

2012-01-01

... diabetes among our Nation’s children is linked to the rise of childhood obesity. To end the epidemic of childhood obesity within a generation, First Lady Michelle Obama’s Let’s Move! initiative is inspiring...

NONPOTABLE WATER REUSE MANAGEMENT PRACTICES

EPA Science Inventory

Globally, the need for water reuse is increasing due to rising water demands and finite water resources. In addition, certain regulations and policies, such as zero discharge initiatives or limited new dam construction, may indirectly contribute to the need for reuse. With growin...

NONPOTABLE WATER REUSE MANAGEMENT PRACTICES

EPA Science Inventory

Globally, the need for water reuse is increasing due to rising water demands and finite water resources. In addition, certain regulations and policies, such as zero discharge initiatives or limited new dam construction, may indirectly contribute to the need for reuse. Also, with ...

Environmental Models as a Service: Enabling Interoperability through RESTful Endpoints and API Documentation

EPA Science Inventory

Achieving interoperability in environmental modeling has evolved as software technology has progressed. The recent rise of cloud computing and proliferation of web services initiated a new stage for creating interoperable systems. Scientific programmers increasingly take advantag...

Environmental Models as a Service: Enabling Interoperability through RESTful Endpoints and API Documentation.

EPA Science Inventory

Achieving interoperability in environmental modeling has evolved as software technology has progressed. The recent rise of cloud computing and proliferation of web services initiated a new stage for creating interoperable systems. Scientific programmers increasingly take advantag...

Volcanic Plume Heights on Mars: Limits of Validity for Convective Models

NASA Technical Reports Server (NTRS)

Glaze, Lori S.; Baloga, Stephen M.

2002-01-01

Previous studies have overestimated volcanic plume heights on Mars. In this work, we demonstrate that volcanic plume rise models, as currently formulated, have only limited validity in any environment. These limits are easily violated in the current Mars environment and may also be violated for terrestrial and early Mars conditions. We indicate some of the shortcomings of the model with emphasis on the limited applicability to current Mars conditions. Specifically, basic model assumptions are violated when (1) vertical velocities exceed the speed of sound, (2) radial expansion rates exceed the speed of sound, (3) radial expansion rates approach or exceed the vertical velocity, or (4) plume radius grossly exceeds plume height. All of these criteria are violated for the typical Mars example given here. Solutions imply that the convective rise, model is only valid to a height of approximately 10 kilometers. The reason for the model breakdown is hat the current Mars atmosphere is not of sufficient density to satisfy the conservation equations. It is likely that diffusion and other effects governed by higher-order differential equations are important within the first few kilometers of rise. When the same criteria are applied to eruptions into a higher-density early Mars atmosphere, we find that eruption rates higher than 1.4 x 10(exp 9) kilograms per second also violate model assumptions. This implies a maximum extent of approximately 65 kilometers for convective plumes on early Mars. The estimated plume heights for both current and early Mars are significantly lower than those previously predicted in the literature. Therefore, global-scale distribution of ash seems implausible.

How will coastal sea level respond to changes in natural and anthropogenic forcings by 2100?

NASA Astrophysics Data System (ADS)

Jevrejeva, S.; Moore, J.; Grinsted, A.

2010-12-01

Sea level rise is perhaps the most damaging repercussion of global warming, as 150 million people live less than one meter above current high tides .Using an inverse statistical model we examine potential response in coastal sea level to the changes in natural and anthropogenic forcings by 2100. With six IPCC radiative forcing scenarios we estimate sea level rise of 0.6-1.6 m, with confidence limits of 0.59 m and 1.8 m. Projected impacts of solar and volcanic radiative forcings account only for, at maximum, 5% of total sea level rise, with anthropogenic greenhouse gasses being the dominant forcing. As alternatives to the IPCC projections, even the most intense century of volcanic forcing from the past 1000 years would result in 10-15 cm potential reduction of sea level rise. Stratospheric injections of SO2 equivalent to a Pinatubo eruption every 4 years would effectively just delay sea level rise by 12 -20 years.

Ferns: the missing link in shoot evolution and development.

PubMed

Plackett, Andrew R G; Di Stilio, Verónica S; Langdale, Jane A

2015-01-01

Shoot development in land plants is a remarkably complex process that gives rise to an extreme diversity of forms. Our current understanding of shoot developmental mechanisms comes almost entirely from studies of angiosperms (flowering plants), the most recently diverged plant lineage. Shoot development in angiosperms is based around a layered multicellular apical meristem that produces lateral organs and/or secondary meristems from populations of founder cells at its periphery. In contrast, non-seed plant shoots develop from either single apical initials or from a small population of morphologically distinct apical cells. Although developmental and molecular information is becoming available for non-flowering plants, such as the model moss Physcomitrella patens, making valid comparisons between highly divergent lineages is extremely challenging. As sister group to the seed plants, the monilophytes (ferns and relatives) represent an excellent phylogenetic midpoint of comparison for unlocking the evolution of shoot developmental mechanisms, and recent technical advances have finally made transgenic analysis possible in the emerging model fern Ceratopteris richardii. This review compares and contrasts our current understanding of shoot development in different land plant lineages with the aim of highlighting the potential role that the fern C. richardii could play in shedding light on the evolution of underlying genetic regulatory mechanisms.

Cylindrical Electrolyser Enhanced Electrokinetic Remediation of Municipal Solid Waste Incineration Fly Ashes

NASA Astrophysics Data System (ADS)

Huang, Tao; Zhou, Lulu; Tao, Junjun; Liu, Longfei

2018-01-01

The paper discusses enhancement and efficiency of removing spiked heavy metal (HM) contaminants from the municipal solid waste incineration (MSWI) fly ashes in the cylindrical electrolyser device. The characterization parameters of the electrolyte solution pH, electric current, electrical conductivity, voltage gradient were discussed after the experiment. The chemical speciation of HMs was analysed between the original samples and remediated ones by BCR sequential extraction. The detoxification efficiencies of Zn, Pb, Cu and Cd in the column-uniform device were compared with that in the traditional rectangular apparatus. The pH value changed smoothly with small amplitude of oscillation in general in cathode and anode compartments except the initial break. The electrical current rapidly increased on the first day of the experiment and steadily declined after that and the electrical conductivity presented a clear rising trend. The residual partition of detoxified samples were obviously lifted which was much higher than the analysis data of the raw materials. The pH and the electrical conductivity in sample region were distributed more uniformly and the blind area was effectively eliminated in the electrolytic cells which was indirectly validated by the contrastive detoxification result of the spiked HMs between the rectangular and cylindrical devices.

Visualizing the dynamic structure of the plant photosynthetic membrane.

PubMed

Ruban, Alexander V; Johnson, Matthew P

2015-11-03

The chloroplast thylakoid membrane is the site for the initial steps of photosynthesis that convert solar energy into chemical energy, ultimately powering almost all life on earth. The heterogeneous distribution of protein complexes within the membrane gives rise to an intricate three-dimensional structure that is nonetheless extremely dynamic on a timescale of seconds to minutes. These dynamics form the basis for the regulation of photosynthesis, and therefore the adaptability of plants to different environments. High-resolution microscopy has in recent years begun to provide new insights into the structural dynamics underlying a number of regulatory processes such as membrane stacking, photosystem II repair, photoprotective energy dissipation, state transitions and alternative electron transfer. Here we provide an overview of the essentials of thylakoid membrane structure in plants, and consider how recent advances, using a range of microscopies, have substantially increased our knowledge of the thylakoid dynamic structure. We discuss both the successes and limitations of the currently available techniques and highlight newly emerging microscopic methods that promise to move the field beyond the current 'static' view of membrane organization based on frozen snapshots to a 'live' view of functional membranes imaged under native aqueous conditions at ambient temperature and responding dynamically to external stimuli.

Emerging therapeutic targets currently under investigation for the treatment of systemic amyloidosis.

PubMed

Nuvolone, Mario; Merlini, Giampaolo

2017-12-01

Systemic amyloidosis occurs when one of a growing list of circulating proteins acquires an abnormal fold, aggregates and gives rise to extracellular amyloid deposits in different body sites, leading to organ dysfunction and eventually death. Current approaches are mainly aimed at lowering the supply of the amyloidogenic precursor or at stabilizing it in a non-amyloidogenic state, thus interfering with the initial phases of amyloid formation and toxicity. Areas covered: Improved understanding of the pathophysiology is indicating novel steps and molecules that could be therapeutically targeted. Here, we will review emerging molecular targets and therapeutic approaches against the main forms of systemic amyloidosis at the early preclinical level. Expert opinion: Conspicuous efforts in drug design and drug discovery have provided an unprecedented list of potential new drugs or therapeutic strategies, from gene-based therapies to small molecules and peptides, from novel monoclonal antibodies to engineered cell-based therapies. The challenge will now be to validate and optimize the most promising candidates, cross the bridge from the preclinical phase to the clinics and identify, through innovative trials design, the safest and most effective combination therapies, striving for a better care, possibly a definitive cure for these diseases.

Multiple Sclerosis.

PubMed

Yamout, Bassem I; Alroughani, Raed

2018-04-01

Multiple sclerosis (MS) is a chronic central nervous system inflammatory disease of autoimmune etiology, mediated by activated T cells with evolving evidence of a significant contribution from B cells and cells of the innate immune system. The disease is thought to be due to a complex interaction between different genetic and environmental factors. The prevalence of MS is rising all over the world, due on one hand to earlier diagnosis and prolonged survival, and on the other to a true increase in incidence of the disease. The diagnosis of MS remains clinical despite recent advances in diagnostics and relies on demonstrating dissemination in space and time while excluding alternative diagnoses. The Mc Donald diagnostic criteria, with their recent 2017 revision, are currently widely accepted in the MS community. Although no cure is yet available, many disease-modifying therapies (DMTs) have shown different levels of efficacy in preventing relapses, accumulation of lesions on magnetic resonance imaging (MRI), and disability progression. Current treatment strategies include gradual escalation based on clinical and radiological criteria that determine treatment response, or initial induction with high efficacy DMTs especially in patients with an early aggressive course. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

The global financial crisis and Australian general practice.

PubMed

McRae, Ian S; Paolucci, Francesco

2011-02-01

To explore the potential effects of the global financial crisis (GFC) on the market for general practitioner (GP) services in Australia. We estimate the impact of changes in unemployment rates on demand for GP services and the impact of lost asset values on GP retirement plans and work patterns. Combining these supply and demand effects, we estimate the potential effect of the GFC on the market for GP services under various scenarios. If deferral of retirement increases GP availability by 2%, and historic trends to reduce GP working hours are halved, at the current level of ~5.2% unemployment average fees would decline by $0.23 per GP consultation and volumes of GP services would rise by 2.53% with almost no change in average GP gross earnings over what would otherwise have occurred. With 8.5% unemployment, as initially predicted by Treasury, GP fees would increase by $0.91 and GP income by nearly 3%. The GFC is likely to increase activity in the GP market and potentially to reduce fee levels relative to the pre-GFC trends. Net effects on average GP incomes are likely to be small at current unemployment levels.

Formation of a bifurcated current layer by the collision of supersonic magnetized plasmas

NASA Astrophysics Data System (ADS)

Suttle, Lee; Hare, Jack; Lebedev, Sergey; Ciardi, Andrea; Loureiro, Nuno; Burdiak, Guy; Chittenden, Jerry; Clayson, Thomas; Ma, Jiming; Niasse, Nicolas; Robinson, Timothy; Smith, Roland; Stuart, Nicolas; Suzuki-Vidal, Francisco

2016-10-01

We present detailed experimental data showing the formation and structure of a current layer produced by the collision of two supersonic and well magnetized plasma flows. The pulsed-power driven setup provides two steady and continuous flows, whose embedded magnetic fields mutually annihilate inside the interaction region giving rise to the current layer. Spatially resolved measurements with Faraday rotation polarimetry, Thomson scattering and laser interferometry diagnostics show the detailed distribution of the magnetic field and other plasma parameters throughout the system. We show that the pile-up of magnetic field ahead of the annihilation gives rise to the multi-layered / bi-directional nature of the current sheet, and we discuss pressure balance and energy exchange mechanisms within the system. This work was supported in part by the Engineering and Physical Sciences Research Council (EPSRC) Grant No. EP/G001324/1, and by the U.S. Department of Energy (DOE) Awards No. DE-F03-02NA00057 and No. DE-SC-0001063.

Note: A rectangular pulse generator for 50 kV voltage, 0.8 ns rise time, and 10 ns pulse width based on polymer-film switch.

PubMed

Wu, Hanyu; Zhang, Xinjun; Sun, Tieping; Zeng, Zhengzhong; Cong, Peitian; Zhang, Shaoguo

2015-10-01

In this article, we describe a rectangular pulse generator, consisting of a polymer-film switch, a tri-plate transmission line, and parallel post-shaped ceramic resistor load, for 50-kV voltage, 0.8-ns rise time, and 10-ns width. The switch and resistors are arranged in atmospheric air and the transmission line can work in atmospheric air or in transformer oil to change the pulse width from 6.7 ns to 10 ns. The fast switching and low-inductance characteristics of the polymer-film switch ensure the fast rising wavefront of <1 ns. This generator can be applied in the calibration of nanosecond voltage dividers and used for electromagnetic pulse tests as a fast-rising current injection source.

Timescales for detecting a significant acceleration in sea level rise

PubMed Central

Haigh, Ivan D.; Wahl, Thomas; Rohling, Eelco J.; Price, René M.; Pattiaratchi, Charitha B.; Calafat, Francisco M.; Dangendorf, Sönke

2014-01-01

There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that we have artificially extended to 2100. We find that the most important approach to earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual to multidecadal variability in sea level records. PMID:24728012

Long-term financing needs for HIV control in sub-Saharan Africa in 2015-2050: a modelling study.

PubMed

Atun, Rifat; Chang, Angela Y; Ogbuoji, Osondu; Silva, Sachin; Resch, Stephen; Hontelez, Jan; Bärnighausen, Till

2016-03-06

To estimate the present value of current and future funding needed for HIV treatment and prevention in 9 sub-Saharan African (SSA) countries that account for 70% of HIV burden in Africa under different scenarios of intervention scale-up. To analyse the gaps between current expenditures and funding obligation, and discuss the policy implications of future financing needs. We used the Goals module from Spectrum, and applied the most up-to-date cost and coverage data to provide a range of estimates for future financing obligations. The four different scale-up scenarios vary by treatment initiation threshold and service coverage level. We compared the model projections to current domestic and international financial sources available in selected SSA countries. In the 9 SSA countries, the estimated resources required for HIV prevention and treatment in 2015-2050 range from US$98 billion to maintain current coverage levels for treatment and prevention with eligibility for treatment initiation at CD4 count of <500/mm(3) to US$261 billion if treatment were to be extended to all HIV-positive individuals and prevention scaled up. With the addition of new funding obligations for HIV--which arise implicitly through commitment to achieve higher than current treatment coverage levels--overall financial obligations (sum of debt levels and the present value of the stock of future HIV funding obligations) would rise substantially. Investing upfront in scale-up of HIV services to achieve high coverage levels will reduce HIV incidence, prevention and future treatment expenditures by realising long-term preventive effects of ART to reduce HIV transmission. Future obligations are too substantial for most SSA countries to be met from domestic sources alone. New sources of funding, in addition to domestic sources, include innovative financing. Debt sustainability for sustained HIV response is an urgent imperative for affected countries and donors. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

RISE: a database of RNA interactome from sequencing experiments

PubMed Central

Gong, Jing; Shao, Di; Xu, Kui

2018-01-01

Abstract We present RISE (http://rise.zhanglab.net), a database of RNA Interactome from Sequencing Experiments. RNA-RNA interactions (RRIs) are essential for RNA regulation and function. RISE provides a comprehensive collection of RRIs that mainly come from recent transcriptome-wide sequencing-based experiments like PARIS, SPLASH, LIGR-seq, and MARIO, as well as targeted studies like RIA-seq, RAP-RNA and CLASH. It also includes interactions aggregated from other primary databases and publications. The RISE database currently contains 328,811 RNA-RNA interactions mainly in human, mouse and yeast. While most existing RNA databases mainly contain interactions of miRNA targeting, notably, more than half of the RRIs in RISE are among mRNA and long non-coding RNAs. We compared different RRI datasets in RISE and found limited overlaps in interactions resolved by different techniques and in different cell lines. It may suggest technology preference and also dynamic natures of RRIs. We also analyzed the basic features of the human and mouse RRI networks and found that they tend to be scale-free, small-world, hierarchical and modular. The analysis may nominate important RNAs or RRIs for further investigation. Finally, RISE provides a Circos plot and several table views for integrative visualization, with extensive molecular and functional annotations to facilitate exploration of biological functions for any RRI of interest. PMID:29040625

Results of the Greenland Ice Sheet Model Initialisation Experiments ISMIP6 - initMIP-Greenland

NASA Astrophysics Data System (ADS)

Goelzer, H.; Nowicki, S.; Edwards, T.; Beckley, M.; Abe-Ouchi, A.; Aschwanden, A.; Calov, R.; Gagliardini, O.; Gillet-chaulet, F.; Golledge, N. R.; Gregory, J. M.; Greve, R.; Humbert, A.; Huybrechts, P.; Larour, E. Y.; Lipscomb, W. H.; Le ´h, S.; Lee, V.; Kennedy, J. H.; Pattyn, F.; Payne, A. J.; Rodehacke, C. B.; Rückamp, M.; Saito, F.; Schlegel, N.; Seroussi, H. L.; Shepherd, A.; Sun, S.; Vandewal, R.; Ziemen, F. A.

2016-12-01

Earlier large-scale Greenland ice sheet sea-level projections e.g. those run during ice2sea and SeaRISE initiatives have shown that ice sheet initialisation can have a large effect on the projections and gives rise to important uncertainties. The goal of this intercomparison exercise (initMIP-Greenland) is to compare, evaluate and improve the initialization techniques used in the ice sheet modeling community and to estimate the associated uncertainties. It is the first in a series of ice sheet model intercomparison activities within ISMIP6 (Ice Sheet Model Intercomparison Project for CMIP6). Two experiments for the large-scale Greenland ice sheet have been designed to allow intercomparison between participating models of 1) the initial present-day state of the ice sheet and 2) the response in two schematic forward experiments. The forward experiments serve to evaluate the initialisation in terms of model drift (forward run without any forcing) and response to a large perturbation (prescribed surface mass balance anomaly). We present and discuss final results of the intercomparison and highlight important uncertainties with respect to projections of the Greenland ice sheet sea-level contribution.

Effect of static shape deformation on aerodynamics and aerothermodynamics of hypersonic inflatable aerodynamic decelerator

NASA Astrophysics Data System (ADS)

Guo, Jinghui; Lin, Guiping; Bu, Xueqin; Fu, Shiming; Chao, Yanmeng

2017-07-01

The inflatable aerodynamic decelerator (IAD), which allows heavier and larger payloads and offers flexibility in landing site selection at higher altitudes, possesses potential superiority in next generation space transport system. However, due to the flexibilities of material and structure assembly, IAD inevitably experiences surface deformation during atmospheric entry, which in turn alters the flowfield around the vehicle and leads to the variations of aerodynamics and aerothermodynamics. In the current study, the effect of the static shape deformation on the hypersonic aerodynamics and aerothermodynamics of a stacked tori Hypersonic Inflatable Aerodynamic Decelerator (HIAD) is demonstrated and analyzed in detail by solving compressible Navier-Stokes equations with Menter's shear stress transport (SST) turbulence model. The deformed shape is obtained by structural modeling in the presence of maximum aerodynamic pressure during entry. The numerical results show that the undulating shape deformation makes significant difference to flow structure. In particular, the more curved outboard forebody surface results in local flow separations and reattachments in valleys, which consequently yields remarkable fluctuations of surface conditions with pressure rising in valleys yet dropping on crests while shear stress and heat flux falling in valleys yet rising on crests. Accordingly, compared with the initial (undeformed) shape, the corresponding differences of surface conditions get more striking outboard, with maximum augmentations of 379 pa, 2224 pa, and 19.0 W/cm2, i.e., 9.8%, 305.9%, and 101.6% for the pressure, shear stress and heat flux respectively. Moreover, it is found that, with the increase of angle of attack, the aerodynamic characters and surface heating vary and the aeroheating disparities are evident between the deformed and initial shape. For the deformable HIAD model investigated in this study, the more intense surface conditions and changed flight aerodynamics are revealed, which is critical for the selection of structure material and design of flight control system.

Experimental Observation of Nonlinear Mode Coupling In the Ablative Rayleigh-Taylor Instability on the NIF

NASA Astrophysics Data System (ADS)

Martinez, David

2015-11-01

We investigate on the National Ignition Facility (NIF) the ablative Rayleigh-Taylor (RT) instability in the transition from linear to highly nonlinear regimes. This work is part of the Discovery Science Program on NIF and of particular importance to indirect-drive inertial confinement fusion (ICF) where careful attention to the form of the rise to final peak drive is calculated to prevent the RT instability from shredding the ablator in-flight and leading to ablator mixing into the cold fuel. The growth of the ablative RT instability was investigated using a planar plastic foil with pre-imposed two-dimensional broadband modulations and diagnosed using x-ray radiography. The foil was accelerated for 12ns by the x-ray drive created in a gas-filled Au radiation cavity with a radiative temperature plateau at 175 eV. The dependence on initial conditions was investigated by systematically changing the modulation amplitude, ablator material and the modulation pattern. For each of these cases bubble mergers were observed and the nonlinear evolution of the RT instability showed insensitivity to the initial conditions. This experiment provides critical data needed to validate current theories on the ablative RT instability for indirect drive that relies on the ablative stabilization of short-scale modulations for ICF ignition. This paper will compare the experimental data to the current nonlinear theories. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC.

Bayesian Statistical Analysis of Historical and Late Holocene Rates of Sea-Level Change

NASA Astrophysics Data System (ADS)

Cahill, Niamh; Parnell, Andrew; Kemp, Andrew; Horton, Benjamin

2014-05-01

A fundamental concern associated with climate change is the rate at which sea levels are rising. Studies of past sea level (particularly beyond the instrumental data range) allow modern sea-level rise to be placed in a more complete context. Considering this, we perform a Bayesian statistical analysis on historical and late Holocene rates of sea-level change. The data that form the input to the statistical model are tide-gauge measurements and proxy reconstructions from cores of coastal sediment. The aims are to estimate rates of sea-level rise, to determine when modern rates of sea-level rise began and to observe how these rates have been changing over time. Many of the current methods for doing this use simple linear regression to estimate rates. This is often inappropriate as it is too rigid and it can ignore uncertainties that arise as part of the data collection exercise. This can lead to over confidence in the sea-level trends being characterized. The proposed Bayesian model places a Gaussian process prior on the rate process (i.e. the process that determines how rates of sea-level are changing over time). The likelihood of the observed data is the integral of this process. When dealing with proxy reconstructions, this is set in an errors-in-variables framework so as to take account of age uncertainty. It is also necessary, in this case, for the model to account for glacio-isostatic adjustment, which introduces a covariance between individual age and sea-level observations. This method provides a flexible fit and it allows for the direct estimation of the rate process with full consideration of all sources of uncertainty. Analysis of tide-gauge datasets and proxy reconstructions in this way means that changing rates of sea level can be estimated more comprehensively and accurately than previously possible. The model captures the continuous and dynamic evolution of sea-level change and results show that not only are modern sea levels rising but that the rates of rise are continuously increasing. Analysis of the a global tide-gauge record (Church and White, 2011) indicated that the rate of sea-level rise increased continuously since 1880AD and is currently 2.57mm/yr (95% credible interval of 1.71 to 4.35mm/yr). Application of the model a proxy reconstruction from North Carolina (Kemp et al., 2011) indicated that the mean rate of rise in this locality since the middle of the 19th century (current rate of 2.66 mm/yr with a 95% credible interval of 1.29 to 4.59mm/yr) is in agreement with results from the tide gauge analysis and is unprecedented in at least the last 2000 years.

Trend analysis of modern high-rise construction

NASA Astrophysics Data System (ADS)

Radushinsky, Dmitry; Gubankov, Andrey; Mottaeva, Asiiat

2018-03-01

The article reviews the main trends of modern high-rise construction considered a number of architectural, engineering and technological, economic and image factors that have influenced the intensification of construction of high-rise buildings in the 21st century. The key factors of modern high-rise construction are identified, which are associated with an attractive image component for businessmen and politicians, with the ability to translate current views on architecture and innovations in construction technologies and the lobbying of relevant structures, as well as the opportunity to serve as an effective driver in the development of a complex of national economy sectors with the achievement of a multiplicative effect. The estimation of the priority nature of participation of foreign architectural bureaus in the design of super-high buildings in Russia at the present stage is given. The issue of economic expediency of construction of high-rise buildings, including those with only a residential function, has been investigated. The connection between the construction of skyscrapers as an important component of the image of cities in the marketing of places and territories, the connection of the availability of a high-rise center, the City, with the possibilities of attracting a "creative class" and the features of creating a large working space for specialists on the basis of territorial proximity and density of high-rise buildings.

Keeping the Faiths

ERIC Educational Resources Information Center

Gray, Katti

2010-01-01

Faced with America's stratified religious landscape, colleges and universities work to embrace spiritual diversity through inclusive discourse, initiatives and programs. Nationwide, some campuses have focused on the rise in religious diversity and mending the religious fractures that persist. They have crafted programs aimed at letting a shifting…

Environmental Models as a Service: Enabling Interoperability through RESTful Endpoints and API Documentation (presentation)

EPA Science Inventory

Achieving interoperability in environmental modeling has evolved as software technology has progressed. The recent rise of cloud computing and proliferation of web services initiated a new stage for creating interoperable systems. Scientific programmers increasingly take advantag...

A double layer model for solar X-ray and microwave pulsations

NASA Technical Reports Server (NTRS)

Tapping, K. F.

1986-01-01

The wide range of wavelengths over which quasi-periodic pulsations have been observed suggests that the mechanism causing them acts upon the supply of high energy electrons driving the emission processes. A model is described which is based upon the radial shrinkage of a magnetic flux tube. The concentration of the current, along with the reduction in the number of available charge carriers, can rise to a condition where the current demand exceeds the capacity of the thermal electrons. Driven by the large inductance of the external current circuit, an instability takes place in the tube throat, resulting in the formation of a potential double layer, which then accelerates electrons and ions to MeV energies. The double layer can be unstable, collapsing and reforming repeatedly. The resulting pulsed particle beams give rise to pulsating emission which are observed at radio and X-ray wavelengths.

Production of atmospheric-pressure glow discharge in nitrogen using needle-array electrode

NASA Astrophysics Data System (ADS)

Takaki, K.; Hosokawa, M.; Sasaki, T.; Mukaigawa, S.; Fujiwara, T.

2005-04-01

An atmospheric pressure glow discharge was generated using a needle-array electrode in nitrogen, and the voltage-current characteristics of the glow discharge were obtained in a range from 1 mA to 60 A. A pulsed high voltage with short rise time under 10 ns was employed to generate streamer discharges simultaneously at all needle tips. The large number of streamer discharges prevented the glow-to-arc transition caused by inhomogeneous thermalization. Semiconductor opening switch diodes were employed as an opening switch to shorten the rise time. The glow voltage was almost constant until the discharge current became 0.3 A, whereas the voltage increased with the current higher than 0.3 A. Electron density and temperature in a positive column of the glow discharge at 60 A were obtained to 1.4×1012cm-3 and 1.3 eV from calculation based on nitrogen swarm data.

The rising cost of NIH-funded biomedical research?

PubMed

Kennedy, T J

1990-02-01

During the last decade, total appropriations for the NIH have grown in current as well as constant dollars. Constant dollar expenditures for indirect costs and research project grants have increased, as also has the number of the latter, while such expenditures for research centers, training, and research contracts have shrunk. The most impressive redistribution in emphasis has been toward traditional research project grants (R01s). The size of the average R01 award, discounted for inflation, has grown at an annual rate of 1.1% during the last decade and 1.3% since fiscal year (FY) 1970; that of the average research program project (P01) has declined over the same periods, after a slight rise in the early 1970s. Factors contributing to the modest rise in the real (constant-dollar) size of the average R01 are explored. The regularity with which current-services-requirements estimates for the NIH exceed inflation reflects real growth in the program, particularly in the category of research project grants; the artifact of basing calculations on the post-rather than pre-"negotiated" levels of awards in the "current" year; and the extent to which the project periods of awards have been extended. The effect of lengthening project periods is slow to become manifest, but inexorably swells the pool of non-competing awards; decisions in this area undertaken in 1985, and continued at least through FY 1988, could very significantly increase current services requirements in FYs 1991 and 1992.

Modeling Holocene Barrier Island Morphodynamics and Potential Future Response to Sea- Level Rise, Outer Banks, North Carolina

NASA Astrophysics Data System (ADS)

Moore, L. J.; List, J. H.; Williams, S. J.; Stolper, D.

2006-12-01

A morphological-behavior model, GEOMBEST, which simulates the evolution of coastal morphology and stratigraphy resulting from changes in sea level and sediment supply provides insight into how barriers evolve over time scales ranging from decades to millenia. The model is based upon behavior rules originating from "Bruun rule" concepts, with additional parameters to allow simulation of more complex real-world scenarios. Morphological evolution in the model is driven by disequilibrium between the shoreface and a user-specified theoretical equilibrium profile that maintains its vertical position relative to sea level. As sea level continues rising to an estimated 48 cm above current MSL by AD 2100 (IPCC 2001) and hurricanes of potentially greater intensity impact the coast, barrier islands will respond either by transgressing across underlying strata or by disintegrating and ultimately submerging. Recent studies suggest that some barriers along the U.S. East Coast will break up and become submerged within decades. Other studies show that barriers in Louisiana have already submerged while others are in the process of narrowing in place and submerging. Several factors determine barrier island response to sea-level rise. These include initial topography and morphology of the barrier, underlying geologic framework, availability and supply of sediment, rate of sea-level rise, frequency and intensity of coastal storms, and anthropogenic modifications to the coast. Sensitivity analyses conducted in GEOMBEST suggest that of these factors, barrier-island response is most sensitive to the rate of sea-level rise. The Holocene evolution of the Outer Banks and potential future responses to sea-level rise are explored for a 25-km stretch of coast between Rodanthe and Cape Hatteras, NC using GEOMBEST. An 8500-year hindcast simulation for the study area reproduces closely the morphology and stratigraphy of the modern barrier with approximately 5 x 109 m3 excavated from the Pleistocene substrate, liberating a volume of material sufficient to construct Diamond Shoals. This hindcast simulation serves as the basis for forward simulations of potential future barrier island evolution. A series of model runs based on the low- (0.09 m), mid- (0.48 m) and upper- (0.88 m) range of IPCC (2001) estimates for sea-level rise by the year 2100, suggest the barrier would migrate at rates of approximately 2, 6 and 10 m/yr, respectively. The latter two results would represent an increase over modern long-term erosion rates in the study area, which serve as a proxy for migration rates. Model simulations of barrier response to 4 and 6 m of sea-level rise by AD 2100 (Overpeck et al., 2006), result in model-generated migration rates of 43 and 68 m/yr, respectively. These rates far exceed the highest average long-term barrier island erosion rates observed today along the Louisiana Coast where the Chandeleur Islands disintegrated in response to Hurricane Katrina. If observations in Louisiana can be applied to barrier islands in North Carolina, then we can expect the Outer Banks to become vulnerable to disintegration when migration rates reach approximately 15-20 m/yr. The five forward simulations for the study area suggest rates in this range may be achieved in the Outer Banks if sea-level rise by AD 2100 exceeds IPCC (2001) estimates.

Asymmetric bubble collapse

NASA Astrophysics Data System (ADS)

Lai, Lipeng; Turitsyn, Konstantin S.; Zhang, Wendy W.

2008-11-01

Recent studies reveal that an inertial implosion, analogous to the collapse of a large cavity in water, governs how a submerged air bubble disconnects from a nozzle. For the bubble, slight asymmetries in the initial neck shape give rise to vibrations that grow pronounced over time. These results motivate our study of the final stage of asymmetric cavity collapse. We are particularly interested in the generic situation where the initial condition is sufficiently well-focused that a cavity can implode inwards energetically. Yet, because the initial condition is not perfectly symmetric, the implosion fails to condense all the energy. We consider cavity shapes in the slender-body limit, for which the collapse dynamics is quasi two-dimensional. In this limit, each cross-section of the cavity evolves as if it were a distorted void immersed in an inviscid and irrotational fluid. Simulations of a circular void distorted by an elongation-compression vibrational mode reveal that a variety of outcomes are possible in the 2D problem. Opposing sides of the void surface can curve inwards and contact smoothly in a finite amount of time. Depending on the phase of the vibration excited, the contact can be either north-south or east-west. Phase values that lie in the transition zone from one orientation to the other give rise to final shapes with large lengthscale separation. We show also that the final outcome varies non-monotonically with the initial amplitude of the vibrational mode.

Contributions of a Strengthened Early Holocene Monsoon and Sediment Loading to Present-Day Subsidence of the Ganges-Brahmaputra Delta

NASA Astrophysics Data System (ADS)

Karpytchev, M.; Ballu, V.; Krien, Y.; Becker, M.; Goodbred, S.; Spada, G.; Calmant, S.; Shum, C. K.; Khan, Z.

2018-02-01

The contribution of subsidence to relative sea level rise in the Ganges-Brahmaputra delta (GBD) is largely unknown and may considerably enhance exposure of the Bengal Basin populations to sea level rise and storm surges. This paper focuses on estimating the present-day subsidence induced by Holocene sediment in the Bengal Basin and by oceanic loading due to eustatic sea level rise over the past 18 kyr. Using a viscoelastic Earth model and sediment deposition history based on in situ measurements, results suggest that massive sediment influx initiated in the early Holocene under a strengthened South Asian monsoon may have contributed significantly to the present-day subsidence of the GBD. We estimate that the Holocene loading generates up to 1.6 mm/yr of the present-day subsidence along the GBD coast, depending on the rheological model of the Earth. This rate is close to the twentieth century global mean sea level rise (1.1-1.7 mm/yr). Thus, past climate change, by way of enhanced sedimentation, is impacting vulnerability of the GBD populations.

Identifying gaps in the continuum of care for cardiovascular disease and diabetes in two communities in South Africa: Baseline findings from the HealthRise project.

PubMed

Wollum, Alexandra; Gabert, Rose; McNellan, Claire R; Daly, Jessica M; Reddy, Priscilla; Bhatt, Paurvi; Bryant, Miranda; Colombara, Danny V; Naidoo, Pamela; Ngongo, Belinda; Nyembezi, Anam; Petersen, Zaino; Phillips, Bryan; Wilson, Shelley; Gakidou, Emmanuela; Duber, Herbert C

2018-01-01

The HealthRise initiative seeks to implement and evaluate innovative community-based strategies for diabetes, hypertension and hypercholesterolemia along the entire continuum of care (CoC)-from awareness and diagnosis, through treatment and control. In this study, we present baseline findings from HealthRise South Africa, identifying gaps in the CoC, as well as key barriers to care for non-communicable diseases (NCDs). This mixed-methods needs assessment utilized national household data, health facility surveys, focus group discussions, and key informant interviews in Umgungundlovu and Pixley ka Seme districts. Risk factor and disease prevalence were estimated from the South Africa National Health and Nutrition Examination Survey. Health facility surveys were conducted at 86 facilities, focusing on essential intervention, medications and standard treatment guidelines. Quantitative results are presented descriptively, and qualitative data was analyzed using a framework approach. 46.8% of the population in Umgungundlovu and 51.0% in Pixley ka Seme were hypertensive. Diabetes was present in 11.0% and 9.7% of the population in Umgungundlovu and Pixley ka Seme. Hypercholesterolemia was more common in Pixley ka Seme (17.3% vs. 11.1%). Women and those of Indian descent were more likely to have diabetes. More than half of the population was found to be overweight, and binge drinking, inactivity and smoking were all common. More than half of patients with hypertension were unaware of their disease status (51.6% in Pixley ka Seme and 51.3% in Umgungundlovu), while the largest gap in the diabetes CoC occurred between initiation of treatment and achieving disease control. Demand-side barriers included lack of transportation, concerns about confidentiality, perceived discrimination and long wait times. Supply-side barriers included limited availability of testing equipment, inadequate staffing, and pharmaceutical stock outs. In this baseline assessment of two South African health districts we found high rates of undiagnosed hypercholesterolemia and hypertension, and poor control of hypercholesterolemia, hypertension, and diabetes. The HealthRise Initiative will need to address key supply- and demand-side barriers in an effort to improve important NCD outcomes.

Allergen-Specific Immunotherapies for Food Allergy

PubMed Central

Feuille, Elizabeth

2018-01-01

With rising prevalence of food allergy (FA), allergen-specific immunotherapy (AIT) for FA has become an active area of research in recent years. In AIT, incrementally increasing doses of inciting allergen are given with the goal to increase tolerance, initially through desensitization, which relies on regular exposure to allergen. With prolonged therapy in some subjects, AIT may induce sustained unresponsiveness, in which tolerance is retained after a period of allergen avoidance. Methods of AIT currently under study in humans include oral, sublingual, epicutaneous, and subcutaneous delivery of modified allergenic protein, as well as via DNA-based vaccines encoding allergen with lysosomal-associated membrane protein I. The balance of safety and efficacy varies by type of AIT, as well as by targeted allergen. Age, degree of sensitization, and other comorbidities may affect this balance within an individual patient. More recently, AIT with modified proteins or combined with immunomodulatory therapies has shown promise in making AIT safer and/or more effective. Though methods of AIT are neither currently advised by experts (oral immunotherapy [OIT]) nor widely available, AIT is likely to become a part of recommended management of FA in the coming years. Here, we review and compare methods of AIT currently under study in humans to prepare the practitioner for an exciting new phase in the care of food allergic patients in which improved tolerance to inciting foods will be a real possibility. PMID:29676066

Operation in low edge safety factor regime and passive disruption avoidance due to stellarator rotational transform in the Compact Toroidal Hybrid

NASA Astrophysics Data System (ADS)

Pandya, M. D.; Ennis, D. A.; Hartwell, G. J.; Maurer, D. A.

2015-11-01

Low edge safety factor operation at a value less than two (q (a) = 1 /ttot (a) < 2) is routine on the Compact Toroidal Hybrid device. Presently, the operational space of this current carrying stellarator extends down to q (a) = 1 . 2 without significant n = 1 kink mode activity after the initial plasma current rise of the discharge. The disruption dynamics of these low q (a) plasmas depend upon the fraction of rotational transform produced by external stellarator coils to that generated by the plasma current. We observe that when about 10% of the total rotational transform is supplied by the stellarator coils, low q (a) disruptions are passively suppressed and avoided even though q (a) < 2 . When the plasma does disrupt, the instability precursors measured and implicated as the cause are internal tearing modes with poloidal, m, and toroidal, n, mode numbers of m / n = 3 / 2 and 4 / 3 observed by external magnetic sensors, and m / n = 1 / 1 activity observed by core soft x-ray emissivity measurements. Even though q (a) passes through and becomes much less than two, external n = 1 kink mode activity does not appear to play a significant role in the observed disruption phenomenology. This work is supported by US Department of Energy Grant No. DE-FG02-00ER54610.

Towards identifying novel anti-Eimeria agents: trace elements, vitamins, and plant-based natural products.

PubMed

Wunderlich, Frank; Al-Quraishy, Saleh; Steinbrenner, Holger; Sies, Helmut; Dkhil, Mohamed A

2014-10-01

Eimeriosis, a widespread infectious disease of livestock, is caused by coccidian protozoans of the genus Eimeria. These obligate intracellular parasites strike the digestive tract of their hosts and give rise to enormous economic losses, particularly in poultry, ruminants including cattle, and rabbit farming. Vaccination, though a rational prophylactic measure, has not yet been as successful as initially thought. Numerous broad-spectrum anti-coccidial drugs are currently in use for treatment and prophylactic control of eimeriosis. However, increasing concerns about parasite resistance, consumer health, and environmental safety of the commercial drugs warrant efforts to search for novel agents with anti-Eimeria activity. This review summarizes current approaches to prevent and treat eimeriosis such as vaccination and commercial drugs, as well as recent attempts to use dietary antioxidants as novel anti-Eimeria agents. In particular, the trace elements selenium and zinc, the vitamins A and E, and natural products extracted from garlic, barberry, pomegranate, sweet wormwood, and other plants are discussed. Several of these novel anti-Eimeria agents exhibit a protective role against oxidative stress that occurs not only in the intestine of Eimeria-infected animals, but also in their non-parasitized tissues, in particular, in the first-pass organ liver. Currently, it appears to be promising to identify safe combinations of low-cost natural products with high anti-Eimeria efficacy for a potential use as feed supplementation in animal farming.

Sensitivity and spin-up times of cohesive sediment transport models used to simulate bathymetric change: Chapter 31

USGS Publications Warehouse

Schoellhamer, D.H.; Ganju, N.K.; Mineart, P.R.; Lionberger, M.A.; Kusuda, T.; Yamanishi, H.; Spearman, J.; Gailani, J. Z.

2008-01-01

Bathymetric change in tidal environments is modulated by watershed sediment yield, hydrodynamic processes, benthic composition, and anthropogenic activities. These multiple forcings combine to complicate simple prediction of bathymetric change; therefore, numerical models are necessary to simulate sediment transport. Errors arise from these simulations, due to inaccurate initial conditions and model parameters. We investigated the response of bathymetric change to initial conditions and model parameters with a simplified zero-dimensional cohesive sediment transport model, a two-dimensional hydrodynamic/sediment transport model, and a tidally averaged box model. The zero-dimensional model consists of a well-mixed control volume subjected to a semidiurnal tide, with a cohesive sediment bed. Typical cohesive sediment parameters were utilized for both the bed and suspended sediment. The model was run until equilibrium in terms of bathymetric change was reached, where equilibrium is defined as less than the rate of sea level rise in San Francisco Bay (2.17 mm/year). Using this state as the initial condition, model parameters were perturbed 10% to favor deposition, and the model was resumed. Perturbed parameters included, but were not limited to, maximum tidal current, erosion rate constant, and critical shear stress for erosion. Bathymetric change was most sensitive to maximum tidal current, with a 10% perturbation resulting in an additional 1.4 m of deposition over 10 years. Re-establishing equilibrium in this model required 14 years. The next most sensitive parameter was the critical shear stress for erosion; when increased 10%, an additional 0.56 m of sediment was deposited and 13 years were required to re-establish equilibrium. The two-dimensional hydrodynamic/sediment transport model was calibrated to suspended-sediment concentration, and despite robust solution of hydrodynamic conditions it was unable to accurately hindcast bathymetric change. The tidally averaged box model was calibrated to bathymetric change data and shows rapidly evolving bathymetry in the first 10-20 years, though sediment supply and hydrodynamic forcing did not vary greatly. This initial burst of bathymetric change is believed to be model adjustment to initial conditions, and suggests a spin-up time of greater than 10 years. These three diverse modeling approaches reinforce the sensitivity of cohesive sediment transport models to initial conditions and model parameters, and highlight the importance of appropriate calibration data. Adequate spin-up time of the order of years is required to initialize models, otherwise the solution will contain bathymetric change that is not due to environmental forcings, but rather improper specification of initial conditions and model parameters. Temporally intensive bathymetric change data can assist in determining initial conditions and parameters, provided they are available. Computational effort may be reduced by selectively updating hydrodynamics and bathymetry, thereby allowing time for spin-up periods. reserved.

Targeting practitioners: A review of guidelines, training, and policy in pain management

PubMed Central

Barth, Kelly S.; Guille, Constance; McCauley, Jenna; Brady, Kathleen T.

2017-01-01

This paper reviews the current literature on clinical guidelines, practitioner training, and government/payer policies that have come forth in response to the national rise in prescription opioid overdoses. A review of clinical opioid prescribing guidelines highlights the need for more research on safe and effective treatment options for chronic pain, improved guidance for the best management of post-operative pain, and evaluation of the implementation and impact of guideline recommendations on patient risk and outcomes. Although there is increasing attention to training in pain management in medical schools and medical residency programs, educational opportunities remain highly variable, and the need for additional clinician training in the recognition and treatment of pain as well as opioid use disorder has been recognized. Mandated use of private, federal and state educational and clinical initiatives such as Risk Evaluation and Mitigation Strategies (REMS) and Prescription Drug Monitoring Programs (PDMPs) generally increase utilization of these initiatives, but more research is needed to determine the impact of these initiatives on provider behaviors, treatment access, and patient outcomes. Finally, there is an acute need for more research on safe and effective treatments for chronic pain as well as an increased multi-level focus on improving training and access to evidence-based treatment for opioid use disorder as well as non-pharmacologic and non-interventional chronic pain treatments, so that these guideline-recommended interventions can become mainstream, accessible, first-line interventions for chronic pain and/or opioid use disorders. PMID:28363316

INVESTIGATING TWO SUCCESSIVE FLUX ROPE ERUPTIONS IN A SOLAR ACTIVE REGION

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

Cheng, X.; Zhang, J.; Ding, M. D.

2013-06-01

We investigate two successive flux rope (FR1 and FR2) eruptions resulting in two coronal mass ejections (CMEs) on 2012 January 23. Both flux ropes (FRs) appeared as an EUV channel structure in the images of high temperature passbands of the Atmospheric Imaging Assembly prior to the CME eruption. Through fitting their height evolution with a function consisting of linear and exponential components, we determine the onset time of the FR impulsive acceleration with high temporal accuracy for the first time. Using this onset time, we divide the evolution of the FRs in the low corona into two phases: a slowmore » rise phase and an impulsive acceleration phase. In the slow rise phase of FR1, the appearance of sporadic EUV and UV brightening and the strong shearing along the polarity inverse line indicates that the quasi-separatrix-layer reconnection likely initiates the slow rise. On the other hand, for FR2, we mainly contribute its slow rise to the FR1 eruption, which partially opened the overlying field and thus decreased the magnetic restriction. At the onset of the impulsive acceleration phase, FR1 (FR2) reaches the critical height of 84.4 ± 11.2 Mm (86.2 ± 13.0 Mm) where the decline of the overlying field with height is fast enough to trigger the torus instability. After a very short interval (∼2 minutes), the flare emission began to enhance. These results reveal the compound activity involving multiple magnetic FRs and further suggest that the ideal torus instability probably plays the essential role of initiating the impulsive acceleration of CMEs.« less

Para-Quantitative Methodology: Reclaiming Experimentalism in Educational Research

ERIC Educational Resources Information Center

Shabani Varaki, Bakhtiar; Floden, Robert E.; Javidi Kalatehjafarabadi, Tahereh

2015-01-01

This article focuses on the criticisms of current approaches in educational research methodology. It summarizes rationales for mixed methods and argues that the mixing quantitative paradigm and qualitative paradigm is problematic due to practical and philosophical arguments. It is also indicated that the current rise of mixed methods work has…

Low-power integrated-circuit driver for ferrite-memory word lines

NASA Technical Reports Server (NTRS)

Katz, S.

1970-01-01

Composite circuit uses both n-p-n bipolar and p-channel MOS transistors /BIMOS/. The BIMOS driver provides 1/ ease of integrated circuit construction, 2/ low standby power consumption, 3/ bidirectional current pulses, and 4/ current-pulse amplitudes and rise times independent of active device parameters.

Providing Counseling for Transgendered Inmates: A Survey of Correctional Services

ERIC Educational Resources Information Center

von Dresner, Kara Sandor; Underwood, Lee A.; Suarez, Elisabeth; Franklin, Timothy

2013-01-01

The purpose of this study was to survey the current assessment, housing, and mental health treatment needs of transsexual inmates within state correctional facilities. The literature reviewed epidemiology, prevalence, multiple uses of terms, assessment, and current standards of care. Along with the rise of the multicultural movement, growing…

Quantum Dot Detector Enhancement for Narrow Band Multispectral Applications

DTIC Science & Technology

2012-10-01

19 2.4.3 Dark Current and Noise Current Measurement of QDIPs.................................21 3 References...20 Figure 19: Dark Current of QDIPs Measured by Source Meter…………………………………………21 Figure 20: Schematic View of Noise Current Setup...temperature, higher photoconductive gain, carrier lifetimes 10-100 times longer than Quantum Well Infrared Photodetectors ( QWIPs ), and giving rise to a

Analysis of the Sources of Islamic Extremism

DTIC Science & Technology

2007-06-15

UN 59th General Assembly and Turkish Prime Minister Erdogan was named the cosponsor. The AOC initiative analyzed the rise in cross-cultural...the founder of al-Qaida, has identified his grievances through audio and video tapes , statements released to the media and through interviews. Bruce

Show What You Know

ERIC Educational Resources Information Center

Brown, Dan; Rhodes, Dwight E.

2017-01-01

Educators Rising, an initiative of PDK International, has developed five microcredentials that allow aspiring teachers to demonstrate what they know and are able to do through experiences very similar to what professional teachers do every day. [This article contains a sidebar: "Microcredentials in the Teacher Academy Classroom: Rigor,…

Economics of oversized cyclones in the cotton ginning industry

USDA-ARS?s Scientific Manuscript database

Cost of reducing pollution to meet increasingly stringent air quality standards particularly for the U.S. cotton ginning industry is rising overtime. Most industry participants use cyclones to control air pollutants. These cyclones have no moving parts and their initial investment costs are relative...

The optical and radiation field signatures produced by lightning return strokes

NASA Technical Reports Server (NTRS)

Guo, C.; Krider, E. P.

1982-01-01

Typical examples of the signals that are produced by first and subsequent return strokes in cloud-to-ground lightning on a microsecond time scale are presented. Statistics on the structure of the waveforms and the radiance of the channels are given. The relationship between the light signals and the associated electric field signatures is discussed. It is shown that the initial light signal from a return stroke tends to be linear for about 15 microsec and then rises more slowly to a peak that is delayed by approximately 60 microsec from the electric field peak. It is thought that the transition between the fast linear portion and the slower rise may be due to the return stroke entering the cloud base. A small percentage of the records suggest that two different branches of the same stepped leader can initiate separate return strokes. The light pulses from cloud discharges tend to be smaller and to vary more slowly than those from return strokes.

Explosive decomposition of ethylene oxide at elevated condition: effect of ignition energy, nitrogen dilution, and turbulence.

PubMed

Pekalski, A A; Zevenbergen, J F; Braithwaite, M; Lemkowitz, S M; Pasman, H J

2005-02-14

Experimental and theoretical investigation of explosive decomposition of ethylene oxide (EO) at fixed initial experimental parameters (T=100 degrees C, P=4 bar) in a 20-l sphere was conducted. Safety-related parameters, namely the maximum explosion pressure, the maximum rate of pressure rise, and the Kd values, were experimentally determined for pure ethylene oxide and ethylene oxide diluted with nitrogen. The influence of the ignition energy on the explosion parameters was also studied. All these dependencies are quantified in empirical formulas. Additionally, the effect of turbulence on explosive decomposition of ethylene oxide was investigated. In contrast to previous studies, it is found that turbulence significantly influences the explosion severity parameters, mostly the rate of pressure rise. Thermodynamic models are used to calculate the maximum explosion pressure of pure and of nitrogen-diluted ethylene oxide, at different initial temperatures. Soot formation was experimentally observed. Relation between the amounts of soot formed and the explosion pressure was experimentally observed and was calculated.

Growth hormone response to feeding in term and preterm neonates.

PubMed

Adrian, T E; Lucas, A; Bloom, S R; Aynsley-Green, A

1983-03-01

Plasma growth hormone concentrations were measured in 248 healthy term and preterm infants. At birth growth hormone concentrations in cord blood from both term and preterm babies were approximately 100-fold higher than those in blood drawn from healthy adults. By the sixth postnatal day basal pre-feed levels had fallen in term neonates by 65% and a marked postprandial rise was apparent; preterm infants did not show this initial fall in preprandial hormone levels nor was any response to feeding seen. However a fall in preprandial concentrations accompanied by the development of postprandial surges in growth hormone occurred during the next 2 weeks so that by 24 days the postprandial rise was similar to that of term neonates on the sixth day. We conclude that although the initial postnatal changes in plasma growth hormone concentrations are different in preterm and term infants, feeding is a major stimulus to growth hormone secretion in both groups of neonates. Further work is needed to define the precise role of this hormone in neonatal metabolic adaptation.

Linear bubble plume model for hypolimnetic oxygenation: Full-scale validation and sensitivity analysis

NASA Astrophysics Data System (ADS)

Singleton, V. L.; Gantzer, P.; Little, J. C.

2007-02-01

An existing linear bubble plume model was improved, and data collected from a full-scale diffuser installed in Spring Hollow Reservoir, Virginia, were used to validate the model. The depth of maximum plume rise was simulated well for two of the three diffuser tests. Temperature predictions deviated from measured profiles near the maximum plume rise height, but predicted dissolved oxygen profiles compared very well with observations. A sensitivity analysis was performed. The gas flow rate had the greatest effect on predicted plume rise height and induced water flow rate, both of which were directly proportional to gas flow rate. Oxygen transfer within the hypolimnion was independent of all parameters except initial bubble radius and was inversely proportional for radii greater than approximately 1 mm. The results of this work suggest that plume dynamics and oxygen transfer can successfully be predicted for linear bubble plumes using the discrete-bubble approach.

The effect of sediments on turbulent plume dynamics in a stratified fluid

NASA Astrophysics Data System (ADS)

Stenberg, Erik; Ezhova, Ekaterina; Brandt, Luca

2017-11-01

We report large eddy simulation results of sediment-loaded turbulent plumes in a stratified fluid. The configuration, where the plume is discharged from a round source, provides an idealized model of subglacial discharge from a submarine tidewater glacier and is a starting point for understanding the effect of sediments on the dynamics of the rising plume. The transport of sediments is modeled by means of an advection-diffusion equation where sediment settling velocity is taken into account. We initially follow the experimental setup of Sutherland (Phys. Rev. Fluids, 2016), considering uniformly stratified ambients and further extend the work to pycnocline-type stratifications typical of Greenland fjords. Apart from examining the rise height, radial spread and intrusion of the rising plume, we gain further insights of the plume dynamics by extracting turbulent characteristics and the distribution of the sediments inside the plume.

Probabilistic Projections of Future Sea-Level Change and Their Implications for Flood Risk Management: Insights from the American Climate Prospectus

NASA Astrophysics Data System (ADS)

Kopp, R. E., III; Delgado, M.; Horton, R. M.; Houser, T.; Little, C. M.; Muir-Wood, R.; Oppenheimer, M.; Rasmussen, D. M., Jr.; Strauss, B.; Tebaldi, C.

2014-12-01

Global mean sea level (GMSL) rise projections are insufficient for adaptation planning; local decisions require local projections that characterize risk over a range of timeframes and tolerances. We present a global set of local sea level (LSL) projections to inform decisions on timescales ranging from the coming decades through the 22nd century. We present complete probability distributions, informed by a combination of expert community assessment, expert elicitation, and process modeling [1]. We illustrate the application of this framework by estimating the joint distribution of future sea-level change and coastal flooding, and associated economic costs [1,2]. In much of the world in the current century, differences in median LSL projections are due primarily to varying levels of non-climatic uplift or subsidence. In the 22nd century and in the high-end tails, larger ice sheet contributions, particularly from the Antarctic ice sheet (AIS), contribute significantly to site-to-site differences. Uncertainty in GMSL and most LSL projections is dominated by the uncertain AIS component. Sea-level rise dramatically reshapes flood risk. For example, at the New York City (Battery) tide gauge, our projections indicate a likely (67% probability) 21st century LSL rise under RCP 8.5 of 65--129 cm (1-in-20 chance of exceeding 154 cm). Convolving the distribution of projected sea-level rise with the extreme value distribution of flood return periods indicates that this rise will cause the current 1.80 m `1-in-100 year' flood event to occur an expected nine times over the 21st century -- equivalent to the expected number of `1-in-11 year' floods in the absence of sea-level change. Projected sea-level rise for 2100 under RCP 8.5 would likely place 80-160 billion of current property in New York below the high tide line, with a 1-in-20 chance of losses >190 billion. Even without accounting for potential changes in storms themselves, it would likely increase average annual storm damage by 2.6-5.2 billion (1-in-20 chance of >7 billion). Projected increases in tropical cyclone intensity would further increase damages [2]. References: [1] R. E. Kopp et al. (2014), Earth's Future, doi:10.1002/2014EF000239. [2] T. Houser et al. (2014), American Climate Prospectus, www.climateprospectus.org.

Arguing for a multi-hazard mapping program in Newfoundland and Labrador, Canada

NASA Astrophysics Data System (ADS)

Batterson, Martin; Neil, Stapleton

2010-05-01

This poster describes efforts to implement a Provincial multi-hazard mapping program, and will explore the challenges associated with this process. Newfoundland and Labrador is on the eastern edge of North America, has a large land area (405,212 km2) and a small population (510,000; 2009 estimate). The province currently has no legislative framework to control development in hazardous areas, but recent landslides in the communities of Daniel's Harbour and Trout River, both of which forced the relocation of residents, emphasize the need for action. There are two factors which confirm the need for a natural hazard mapping program: the documented history of natural disasters, and the future potential impacts of climate change. Despite being relatively far removed from the impacts of earthquake and volcanic activity, Newfoundland and Labrador has a long history of natural disasters. Rockfall, landslide, avalanche and flood events have killed at least 176 people over the past 225 years, many in their own homes. Some of the fatalities resulted from the adjacency of homes to places of employment, and of communities and roads to steep slopes. Others were likely the result of chance, and were thus unavoidable. Still others were the result of poor planning, albeit unwitting. Increasingly however, aesthetics have replaced pragmatism as a selection criterion for housing developments, with residential construction being contemplated for many coastal areas. The issue is exacerbated by the impacts of climate change, which while not a universal bane for the Province, will likely result in rising sea level and enhanced coastal erosion. Much of the Province's coastline is receding at up to 30 cm (and locally higher) per year. Sea level is anticipated to rise by 70cm to over 100 cm by 2099, based on IPCC predictions, plus the effects of enhanced ice sheet melting, plus (or minus) continued local isostatic adjustment. The history of geological disasters, coupled with pressures on development and the threat of rising sea levels, has prompted the initiation of a Provincial multi-hazard mapping program. Initial focus is on the north-east Avalon Peninsula, where the majority of the Province's residents are located and where most development is occurring. A regional land-use plan is being initiated for this area. While there are few, if any, standard protocols in literature for determining variables/data to be included in a hazard assessment, three important factors require consideration: the characteristics and detail of the study area, the availability of digital datasets, and the scale of data. For the north-east Avalon Peninsula hazard mapping will combine slope models generated from DEMs, bedrock/surficial geology mapping at 1:50,000 scale, Provincial flood risk mapping and municipal digital topographic data at 1:2500 scale, and historical research and field work, to produce a ‘traffic-light' designation of potentially hazardous areas. Data will be presented in an ArcGIS environment. Sea-level rise scenarios will also be incorporated into the mapping. Following the experience of flood risk mapping in the Province, which identified hazardous areas for development which nevertheless continued to experience urban expansion, subsequently ensuring the utilization of these maps in future land-use planning will likely require entrenchment in legislation.

The early dynamical evolution of star clusters near the Galactic Centre

NASA Astrophysics Data System (ADS)

Park, So-Myoung; Goodwin, Simon P.; Kim, Sungsoo S.

2018-07-01

We examine the dynamical evolution of both Plummer sphere and substructured (fractal) star-forming regions in Galactic Centre (GC) strong tidal fields to see what initial conditions could give rise to an Arches-like massive star cluster by ˜2 Myr. We find that any initial distribution has to be contained within its initial tidal radius to survive, which sets a lower limit of the initial density of the Arches of ˜600 M⊙ pc-3 if the Arches is at 30 pc from the GC, or ˜200 M⊙ pc-3 if the Arches is at 100 pc from the GC. Plummer spheres that survive change little other than to dynamically mass segregate, but initially fractal distributions rapidly erase substructure, dynamically mass segregate and by 2 Myr look extremely similar to initial Plummer spheres, therefore it is almost impossible to determine the initial conditions of clusters in strong tidal fields.

The early dynamical evolution of star clusters near the Galactic Centre

NASA Astrophysics Data System (ADS)

Park, So-Myoung; Goodwin, Simon P.; Kim, Sungsoo S.

2018-04-01

We examine the dynamical evolution of both Plummer sphere and substructured (fractal) star forming regions in Galactic Centre (GC) strong tidal fields to see what initial conditions could give rise to an Arches-like massive star cluster by ˜2 Myr. We find that any initial distribution has to be contained within its initial tidal radius to survive, which sets a lower limit of the initial density of the Arches of ˜ 600 M⊙ pc-3 if the Arches is at 30 pc from the GC, or ˜ 200 M⊙ pc-3 if the Arches is at 100 pc from the GC. Plummer spheres that survive change little other than to dynamically mass segregate, but initially fractal distributions rapidly erase substructure, dynamically mass segregate and by 2 Myr look extremely similar to initial Plummer spheres, therefore it is almost impossible to determine the initial conditions of clusters in strong tidal fields.

The impact of a general practice group intervention on prescribing costs and patterns.

PubMed Central

Walker, Jane; Mathers, Nigel

2002-01-01

BACKGROUND: The formation of primary care groups (PCGs) and trusts (PCTs) has shifted the emphasis from individual practice initiatives to group-based efforts to control rising prescribing costs. However, there is a paucity of literature describing such group initiatives. We report the results of a multilevel group initiative, involving input from a pharmaceutical adviser, practice comparison feedback, and peer review meetings. AIM: To determine the impact of a prescribing initiative on the prescribing patterns of a group of general practices. DESIGN OF STUDY: A comparative study with non-matched controls. SETTING: Nine semi-rural/rural practices forming a commissioning group pilot, later a PCG, in Southern Derbyshire with nine practices as controls. METHOD: Practice data were collated for overall prescribing and for therapeutic categories, between the years 1997/1998 and 1998/1999 and analysed statistically. Prescribing expenditure trends were also collated. RESULTS: Although both groups came well within their prescribing budgets, in the study group this was for the first time in five years. Their rate of increase in expenditure slowed significantly following the initiative compared with that of the comparison group, which continued to rise (median practice net ingredient cost/patient unit (nic/PU) increase: Pound Sterling0.69 and Pound Sterling3.80 respectively; P = 0.03). The study group's nic/PU dropped below, and stayed below, that of the comparison group one month after the start of the initiative. For most therapeutic categories the study group had lower increases in costs and higher increases in percentage of generic items than the comparison group. Quality markers were unaffected. CONCLUSION: We suggest that practices with diverse prescribing patterns can work together effectively within a PCT locality to control prescribing costs. PMID:12030659

Determination of Temperature Rise and Temperature Differentials of CEMII/B-V Cement for 20MPa Mass Concrete using Adiabatic Temperature Rise Data

NASA Astrophysics Data System (ADS)

Chee Siang, GO

2017-07-01

Experimental test was carried out to determine the temperature rise characteristics of Portland-Fly-Ash Cement (CEM II/B-V, 42.5N) of Blaine fineness 418.6m2/kg and 444.6m2/kg respectively for 20MPa mass concrete under adiabatic condition. The estimation on adiabatic temperature rise by way of CIRIA C660 method (Construction Industry Research & Information Information) was adopted to verify and validate the hot-box test results by simulating the heat generation curve of the concrete under semi-adiabatic condition. Test result found that Portland fly-ash cement has exhibited decrease in the peak value of temperature rise and maximum temperature rise rate. The result showed that the temperature development and distribution profile, which is directly contributed from the heat of hydration of cement with time, is affected by the insulation, initial placing temperature, geometry and size of concrete mass. The mock up data showing the measured temperature differential is significantly lower than the technical specifications 20°C temperature differential requirement and the 27.7°C limiting temperature differential for granite aggregate concrete as stipulated in BS8110-2: 1985. The concrete strength test result revealed that the 28 days cubes compressive strength was above the stipulated 20MPa characteristic strength at 90 days. The test demonstrated that with proper concrete mix design, the use of Portland flyash cement, combination of chilled water and flake ice, and good insulation is effective in reducing peak temperature rise, temperature differential, and lower adiabatic temperature rise for mass concrete pours. As far as the determined adiabatic temperature rise result was concern, the established result could be inferred for in-situ thermal properties of 20MPa mass concrete application, as the result could be repeatable on account of similar type of constituent materials and concrete mix design adopted for permanent works at project site.

Developing Coastal Adaptation to Climate Change in the New York City Infrastructure-Shed: Process, Approach, Tools, and Strategies

NASA Technical Reports Server (NTRS)

Rosenzweig, Cynthia; Solecki, William D.; Blake, Reginald; Bowman, Malcolm; Faris, Craig; Gornitz, Vivien; Horton, Radley; Jacob, Klaus; LeBlanc, Alice; Leichenko, Robin;

New Phenomena in High Temperature Nanofriction on Nonmelting Surfaces: NaCl(100)

NASA Astrophysics Data System (ADS)

Zykova-Timan, Tatyana; Ceresoli, Davide; Tosatti, Erio

2006-03-01

High temperature nanofriction is a difficult and so far unexplored area whwere we made an initial attack by means of simulation. Alkali halide (100) surfaces were chosen as they would not automatically liquefy under a sliding tip, even at temperatures very close to the melting point. We conducted sliding friction molecular dynamics simulations of hard tips on NaCl(100),both in the heavy ploughing, wear-dominated regime, and in the light grazing, wearless regime. Ploughing friction shows for increasing temperature a strong frictional drop near the melting point. Here the tip can be characterized as ``skating'' over the hot solid, its apex surrounded by a local liquid halo, which moves along with the tip as it ploughs on. At the opposite extreme, we find that grazing friction of a lightly pressed flat-ended tip behaves just the other way around. Starting with an initially very weak low temperature frictional force, there is a surge of friction just near the melting point, where the surface is still solid, but not too far from a vibrational instability. This frictional rise can be envisaged as an analog of the celebrated ``peak effect'' found close to Hc2 in the mixed state critical current of type II superconductors.

Opioid Analgesics for Chronic Non-Cancer Pain: A Guideline on Opioid Prescribing.

PubMed

Van Demark, Robert; Chang, Peter; Heinemann, Daniel

2016-01-01

Over the past decade, the use of opioid analgesics has risen dramatically both in the U.S. and South Dakota. Opioids have been increasingly used to treat chronic non-cancer pain; however, the utilization of opioids for this role has limited and questionable utility. The U.S. has also seen a rise of opioid abuse, addiction, misuse, and overdose. The various pharmacological and non-pharmacological strategies to help physicians manage chronic non-cancer pain and a guideline on appropriate opioid prescribing are presented. Before the decision is made to begin opioid therapy for chronic non-cancer pain, other pharmacological and non-pharmacological therapeutic strategies should be explored. The schema for responsible opioid prescribing can be dived into the following: the initial assessment, initiating opioid therapy, maintenance therapy, and the discontinuation of opioid treatment. These categories are explored, and a general approach to prescribing opioids for chronic non-cancer pain is presented. The Centers for Disease Control and Prevention (CDC) has declared opioid prescription abuse an "epidemic." There are a variety of methods clinicians can utilize to relieve chronic non-cancer pain. If opioid therapy is sought, clinicians should be mindful of the current state of opioid abuse and misuse. This guideline may aid clinicians in appropriate opioid prescribing.

Experimental Study on Influence of Trap Parameters on Dielectric Characteristics of Nano-Modified Insulation Pressboard

PubMed Central

Chen, Qingguo; Liu, Heqian; Chi, Minghe; Wang, Yonghong; Wei, Xinlao

2017-01-01

In order to study the influence of trap parameters on dielectric characteristics of nano-modified pressboards, pressboards were made using the nano doping method with different nanoparticle components. The dielectric characteristics of the modified pressboards were measured, and the trap parameters were investigated using the thermally stimulated current (TSC) method. The test results indicated that the conductivity initially declined and then rose with the increase of nano-Al2O3 content, whereas it solely rose with the increase of nano-SiC content. Moreover, the conductivity exhibited nonlinear characteristics with the enhancement of electric field stress at high nanoparticle content. The relative permittivity of modified pressboard declines initially and then rises with the increase of nanoparticle content. In addition, the breakdown strength of modified pressboards exhibited a pattern of incline followed by decline with the increase of nano-Al2O3 content, while it always declined with the increase of nano-SiC content. The analysis based on the energy band theory on trap parameters of the constructed multi-core model concludes that the nanoparticle components added in pressboard altered both the depth and density of traps. It is therefore concluded that trap parameters have significant influence on the dielectric characteristics of nano-modified insulation pressboard. PMID:28772448

Experimental Study on Influence of Trap Parameters on Dielectric Characteristics of Nano-Modified Insulation Pressboard.

PubMed

Chen, Qingguo; Liu, Heqian; Chi, Minghe; Wang, Yonghong; Wei, Xinlao

2017-01-22

In order to study the influence of trap parameters on dielectric characteristics of nano-modified pressboards, pressboards were made using the nano doping method with different nanoparticle components. The dielectric characteristics of the modified pressboards were measured, and the trap parameters were investigated using the thermally stimulated current (TSC) method. The test results indicated that the conductivity initially declined and then rose with the increase of nano-Al₂O₃ content, whereas it solely rose with the increase of nano-SiC content. Moreover, the conductivity exhibited nonlinear characteristics with the enhancement of electric field stress at high nanoparticle content. The relative permittivity of modified pressboard declines initially and then rises with the increase of nanoparticle content. In addition, the breakdown strength of modified pressboards exhibited a pattern of incline followed by decline with the increase of nano-Al₂O₃ content, while it always declined with the increase of nano-SiC content. The analysis based on the energy band theory on trap parameters of the constructed multi-core model concludes that the nanoparticle components added in pressboard altered both the depth and density of traps. It is therefore concluded that trap parameters have significant influence on the dielectric characteristics of nano-modified insulation pressboard.

Extrinsic pseudocapacitve Li-ion storage of SnS anode via lithiation-induced structural optimization on cycling

NASA Astrophysics Data System (ADS)

Lian, Qingwang; Zhou, Gang; Liu, Jiatu; Wu, Chen; Wei, Weifeng; Chen, Libao; Li, Chengchao

2017-10-01

Here, we report a new enhanced extrinsic pseudocapacitve Li-ion storage mechanism via lithiation-induced structural optimization strategy. The flower-like C@SnS and bulk SnS exhibit initial capacity decay and subsequent increase of capacity on cycling. After a long-term lithiation/delithiation process, flower-like C@SnS and bulk SnS exhibit improved rate performance and reversible capacity in comparison with those of initial state. Moreover, a high capacity of 530 mAh g-1 is still remained even after 1550 cycles at a high current density of 5.0 A g-1 for flower-like C@SnS after pre-lithiation of 350 cycles. According to the comprehensive analysis of structural evolution and electrochemical performance, it demonstrates that SnS electrodes experience crystal size reduction and further amorphization on cycling, which enhances the reversibility of conversion reaction for SnS, leading to increasing capacity. On the other hand, surface-dominated extrinsic pseudocapacitive contribution results in enhanced rate performance because electrodes expose a large fraction of Li+ sites on surface or near-surface region with structural optimization on cycling. This study reveals that extrinsic pseudocapacitance of SnS can be stimulated via lithiation-induced structural optimization, which gives rise to high-rate and long-lived performances.

Covariation of axon initial segment location and dendritic tree normalizes the somatic action potential

PubMed Central

Hamada, Mustafa S.; Goethals, Sarah; de Vries, Sharon I.; Brette, Romain

2016-01-01

In mammalian neurons, the axon initial segment (AIS) electrically connects the somatodendritic compartment with the axon and converts the incoming synaptic voltage changes into a temporally precise action potential (AP) output code. Although axons often emanate directly from the soma, they may also originate more distally from a dendrite, the implications of which are not well-understood. Here, we show that one-third of the thick-tufted layer 5 pyramidal neurons have an axon originating from a dendrite and are characterized by a reduced dendritic complexity and thinner main apical dendrite. Unexpectedly, the rising phase of somatic APs is electrically indistinguishable between neurons with a somatic or a dendritic axon origin. Cable analysis of the neurons indicated that the axonal axial current is inversely proportional to the AIS distance, denoting the path length between the soma and the start of the AIS, and to produce invariant somatic APs, it must scale with the local somatodendritic capacitance. In agreement, AIS distance inversely correlates with the apical dendrite diameter, and model simulations confirmed that the covariation suffices to normalize the somatic AP waveform. Therefore, in pyramidal neurons, the AIS location is finely tuned with the somatodendritic capacitive load, serving as a homeostatic regulation of the somatic AP in the face of diverse neuronal morphologies. PMID:27930291

Effect of 5-hydroxytryptophan acting from the cerebral ventricles on 5-hydroxytryptamine output and body temperature

PubMed Central

El Hawary, M. B. E.; Feldberg, W.

1966-01-01

1. In cats anaesthetized with intraperitoneal pentobarbitone sodium the third ventricle, the anterior or inferior horn of the left lateral ventricle, was perfused with 5-hydroxytryptophan (5-HTP) in different concentrations, and the effluent assayed for 5-hydroxytryptamine (5-HT) on the rat stomach strip preparation of Vane (1957). 2. On perfusion of the third ventricle with 5-HTP the output of 5-HT in effluent increased, the increase depending on the 5-HTP concentration: with 1/50,000 it increased 44-69 times (mean 55), with 1/25,000, 81-83 times (mean 82) and with 1/10,000, 71-200 times (mean 128). The 5-HT output depended also on the initial output during the preceding perfusion with artificial c.s.f. The greater this initial output the greater was the maximum output reached during the 5-HTP perfusion. 3. The increase in 5-HT output during perfusion of the third ventricle with 5-HTP was usually associated with shivering and a rise in rectal temperature. This association, however, was not invariably obtained, probably because of a central depressant effect of 5-HTP itself. 4. On perfusion of the anterior or inferior horn of the left lateral ventricle with 5-HTP, the output of 5-HT in the effluent also increased, but to a lesser extent than in the effluent from the third ventricle. There was no association with shivering nor with a rise in rectal temperature. 5. An injection of 1 or 2 mg 5—HTP into the cerebral ventricles of unanaesthetized cats produced a biphasic rise in temperature, shivering, constriction of the skin vessels followed by vasodilatation, tachypnoea, wiping and scratching movements, miaowing and long lasting sleep. 6. The biphasic rise in temperature is explained as the result of two opposing effects: increased formation of 5-HT which would raise body temperature, and a central depressant effect of 5-HTP itself or of one of its metabolites which would lower body temperature. 7. The initial rise in temperature and the shivering in response to an intraventricular injection of 5-HTP varied from cat to cat. In those in which these effects were strong the 5-HT output during a subsequent perfusion of the third ventricle with artificial c.s.f. was higher, and the maximum 5—HT output reached on perfusion with 5-HTP was greater than in those in which these effects had been weak. PMID:5298335

Integrated carbon budget models for the Everglades terrestrial-coastal-oceanic gradient: Current status and needs for inter-site comparisons

USGS Publications Warehouse

Troxler, Tiffany G.; Gaiser, Evelyn; Barr, Jordan; Fuentes, Jose D.; Jaffe, Rudolf; Childers, Daniel L.; Collado-Vides, Ligia; Rivera-Monroy, Victor H.; Castañeda-Moya, Edward; Anderson, William; Chambers, Randy; Chen, Meilian; Coronado-Molina, Carlos; Davis, Stephen E.; Engel, Victor C.; Fitz, Carl; Fourqurean, James; Frankovich, Tom; Kominoski, John; Madden, Chris; Malone, Sparkle L.; Oberbauer, Steve F.; Olivas, Paulo; Richards, Jennifer; Saunders, Colin; Schedlbauer, Jessica; Scinto, Leonard J.; Sklar, Fred; Smith, Thomas J.; Smoak, Joseph M.; Starr, Gregory; Twilley, Robert; Whelan, Kevin

2013-01-01

Recent studies suggest that coastal ecosystems can bury significantly more C than tropical forests, indicating that continued coastal development and exposure to sea level rise and storms will have global biogeochemical consequences. The Florida Coastal Everglades Long Term Ecological Research (FCE LTER) site provides an excellent subtropical system for examining carbon (C) balance because of its exposure to historical changes in freshwater distribution and sea level rise and its history of significant long-term carbon-cycling studies. FCE LTER scientists used net ecosystem C balance and net ecosystem exchange data to estimate C budgets for riverine mangrove, freshwater marsh, and seagrass meadows, providing insights into the magnitude of C accumulation and lateral aquatic C transport. Rates of net C production in the riverine mangrove forest exceeded those reported for many tropical systems, including terrestrial forests, but there are considerable uncertainties around those estimates due to the high potential for gain and loss of C through aquatic fluxes. C production was approximately balanced between gain and loss in Everglades marshes; however, the contribution of periphyton increases uncertainty in these estimates. Moreover, while the approaches used for these initial estimates were informative, a resolved approach for addressing areas of uncertainty is critically needed for coastal wetland ecosystems. Once resolved, these C balance estimates, in conjunction with an understanding of drivers and key ecosystem feedbacks, can inform cross-system studies of ecosystem response to long-term changes in climate, hydrologic management, and other land use along coastlines

Assessing storm surge hazard and impact of sea level rise in the Lesser Antilles case study of Martinique

NASA Astrophysics Data System (ADS)

Krien, Yann; Dudon, Bernard; Roger, Jean; Arnaud, Gael; Zahibo, Narcisse

2017-09-01

In the Lesser Antilles, coastal inundations from hurricane-induced storm surges pose a great threat to lives, properties and ecosystems. Assessing current and future storm surge hazards with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave-current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique under present climate or considering a potential sea level rise. Results confirm that the wave setup plays a major role in the Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge - up to 100 % in some cases. The nonlinear interactions of sea level rise (SLR) with bathymetry and topography are generally found to be relatively small in Martinique but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.

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.

The importance of plume rise on the concentrations and atmospheric impacts of biomass burning aerosol

NASA Astrophysics Data System (ADS)

Walter, Carolin; Freitas, Saulo R.; Kottmeier, Christoph; Kraut, Isabel; Rieger, Daniel; Vogel, Heike; Vogel, Bernhard

2016-07-01

We quantified the effects of the plume rise of biomass burning aerosol and gases for the forest fires that occurred in Saskatchewan, Canada, in July 2010. For this purpose, simulations with different assumptions regarding the plume rise and the vertical distribution of the emissions were conducted. Based on comparisons with observations, applying a one-dimensional plume rise model to predict the injection layer in combination with a parametrization of the vertical distribution of the emissions outperforms approaches in which the plume heights are initially predefined. Approximately 30 % of the fires exceed the height of 2 km with a maximum height of 8.6 km. Using this plume rise model, comparisons with satellite images in the visible spectral range show a very good agreement between the simulated and observed spatial distributions of the biomass burning plume. The simulated aerosol optical depth (AOD) with data of an AERONET station is in good agreement with respect to the absolute values and the timing of the maximum. Comparison of the vertical distribution of the biomass burning aerosol with CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) retrievals also showed the best agreement when the plume rise model was applied. We found that downwelling surface short-wave radiation below the forest fire plume is reduced by up to 50 % and that the 2 m temperature is decreased by up to 6 K. In addition, we simulated a strong change in atmospheric stability within the biomass burning plume.

Northeast Artificial Intelligence Consortium (NAIC). Volume 3. The Versatile Maintenance Expert System (VMES)

DTIC Science & Technology

1990-12-01

expected values. However, because the same good /bad output pattern of a device always gives rise to the same initial ordering, the method has its limitation...For any device and good /bad output pattern, it is easy to come up with an example on which the method does poorly in the sense that the actual...submodule is hss likely to be faulty if it is connec d to more good primary outputs. Initially, candidates are ordered according to their relat -nships with

Analyzing Recent Coronary Heart Disease Mortality Trends in Tunisia between 1997 and 2009

PubMed Central

Saidi, Olfa; Ben Mansour, Nadia; O’Flaherty, Martin; Capewell, Simon; Critchley, Julia A.; Romdhane, Habiba Ben

2013-01-01

Background In Tunisia, Cardiovascular Diseases are the leading causes of death (30%), 70% of those are coronary heart disease (CHD) deaths and population studies have demonstrated that major risk factor levels are increasing. Objective To explain recent CHD trends in Tunisia between 1997 and 2009. Methods Data Sources: Published and unpublished data were identified by extensive searches, complemented with specifically designed surveys. Analysis Data were integrated and analyzed using the previously validated IMPACT CHD policy model. Data items included: (i)number of CHD patients in specific groups (including acute coronary syndromes, congestive heart failure and chronic angina)(ii) uptake of specific medical and surgical treatments, and(iii) population trends in major cardiovascular risk factors (smoking, total cholesterol, systolic blood pressure (SBP), body mass index (BMI), diabetes and physical inactivity). Results CHD mortality rates increased by 11.8% for men and 23.8% for women, resulting in 680 additional CHD deaths in 2009 compared with the 1997 baseline, after adjusting for population change. Almost all (98%) of this rise was explained by risk factor increases, though men and women differed. A large rise in total cholesterol level in men (0.73 mmol/L) generated 440 additional deaths. In women, a fall (−0.43 mmol/L), apparently avoided about 95 deaths. For SBP a rise in men (4 mmHg) generated 270 additional deaths. In women, a 2 mmHg fall avoided 65 deaths. BMI and diabetes increased substantially resulting respectively in 105 and 75 additional deaths. Increased treatment uptake prevented about 450 deaths in 2009. The most important contributions came from secondary prevention following Acute Myocardial Infarction (AMI) (95 fewer deaths), initial AMI treatments (90), antihypertensive medications (80) and unstable angina (75). Conclusions Recent trends in CHD mortality mainly reflected increases in major modifiable risk factors, notably SBP and cholesterol, BMI and diabetes. Current prevention strategies are mainly focused on treatments but should become more comprehensive. PMID:23658808

Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045.

PubMed

Dahl, Kristina A; Fitzpatrick, Melanie F; Spanger-Siegfried, Erika

2017-01-01

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001-2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years.

Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045

PubMed Central

Fitzpatrick, Melanie F.; Spanger-Siegfried, Erika

2017-01-01

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001–2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years. PMID:28158209

49 CFR 229.77 - Current collectors.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229... engineer's normal position in the cab. Pantographs that automatically rise when released shall have an...

49 CFR 229.77 - Current collectors.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229... engineer's normal position in the cab. Pantographs that automatically rise when released shall have an...

49 CFR 229.77 - Current collectors.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229... engineer's normal position in the cab. Pantographs that automatically rise when released shall have an...

49 CFR 229.77 - Current collectors.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229... engineer's normal position in the cab. Pantographs that automatically rise when released shall have an...

49 CFR 229.77 - Current collectors.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229... engineer's normal position in the cab. Pantographs that automatically rise when released shall have an...

Can a small-changes approach help address the obesity epidemic? A report of the Joint Task Force of the American Society for Nutrition, Institute of Food Technologists, and International Food Information Council.

PubMed

Hill, James O

2009-02-01

The continued rise in obesity rates in most countries suggests that current programs and initiatives designed to combat obesity have not been successful in reversing the obesity epidemic. Obesity rates are increasing because of a gradual weight gain in most populations. There has been little long-term success in treating established obesity through lifestyle change, perhaps because of the large permanent changes in diet and physical activity required to keep weight off. An alternative strategy to address the obesity epidemic involves not focusing on weight loss but promoting small changes in diet and physical activity to initially prevent further weight gain. With the use of this strategy, obesity rates could first be stabilized in most populations and then, over time, decrease gradually. Supporting data show that small reductions in conscious energy intake and increases in physical activity can reduce excessive weight gain. The opportunity exists to use the small-changes approach to bring different stakeholders together to create a national initiative to address the global epidemic of obesity. The Joint Task Force of the American Society for Nutrition, Institute of Food Technologists, and International Food Information Council believe that a small-changes framework, aimed at helping people make conscious small changes in lifestyle behaviors, in combination with efforts by the private sector to gradually "ratchet down" some of the environmental factors that have contributed to excessive energy intake and the declining rates of physical activity, can be successful in reducing obesity rates. Such an initiative would benefit from the support of educational and social marketing campaigns developed with governmental input and support.

Voltage Gating of Shaker K+ Channels

PubMed Central

Rodríguez, Beatriz M.; Sigg, Daniel; Bezanilla, Francisco

1998-01-01

Ionic (Ii) and gating currents (Ig) from noninactivating Shaker H4 K+ channels were recorded with the cut-open oocyte voltage clamp and macropatch techniques. Steady state and kinetic properties were studied in the temperature range 2–22°C. The time course of Ii elicited by large depolarizations consists of an initial delay followed by an exponential rise with two kinetic components. The main Ii component is highly temperature dependent (Q10 > 4) and mildly voltage dependent, having a valence times the fraction of electric field (z) of 0.2–0.3 eo. The Ig On response obtained between −60 and 20 mV consists of a rising phase followed by a decay with fast and slow kinetic components. The main Ig component of decay is highly temperature dependent (Q10 > 4) and has a z between 1.6 and 2.8 eo in the voltage range from −60 to −10 mV, and ∼0.45 eo at more depolarized potentials. After a pulse to 0 mV, a variable recovery period at −50 mV reactivates the gating charge with a high temperature dependence (Q10 > 4). In contrast, the reactivation occurring between −90 and −50 mV has a Q10 = 1.2. Fluctuation analysis of ionic currents reveals that the open probability decreases 20% between 18 and 8°C and the unitary conductance has a low temperature dependence with a Q10 of 1.44. Plots of conductance and gating charge displacement are displaced to the left along the voltage axis when the temperature is decreased. The temperature data suggests that activation consists of a series of early steps with low enthalpic and negative entropic changes, followed by at least one step with high enthalpic and positive entropic changes, leading to final transition to the open state, which has a negative entropic change. PMID:9689029

Comparative Study of Three Data Assimilation Methods for Ice Sheet Model Initialisation

NASA Astrophysics Data System (ADS)

Mosbeux, Cyrille; Gillet-Chaulet, Fabien; Gagliardini, Olivier

2015-04-01

The current global warming has direct consequences on ice-sheet mass loss contributing to sea level rise. This loss is generally driven by an acceleration of some coastal outlet glaciers and reproducing these mechanisms is one of the major issues in ice-sheet and ice flow modelling. The construction of an initial state, as close as possible to current observations, is required as a prerequisite before producing any reliable projection of the evolution of ice-sheets. For this step, inverse methods are often used to infer badly known or unknown parameters. For instance, the adjoint inverse method has been implemented and applied with success by different authors in different ice flow models in order to infer the basal drag [ Schafer et al., 2012; Gillet-chauletet al., 2012; Morlighem et al., 2010]. Others data fields, such as ice surface and bedrock topography, are easily measurable with more or less uncertainty but only locally along tracks and interpolated on finer model grid. All these approximations lead to errors on the data elevation model and give rise to an ill-posed problem inducing non-physical anomalies in flux divergence [Seroussi et al, 2011]. A solution to dissipate these divergences of flux is to conduct a surface relaxation step at the expense of the accuracy of the modelled surface [Gillet-Chaulet et al., 2012]. Other solutions, based on the inversion of ice thickness and basal drag were proposed [Perego et al., 2014; Pralong & Gudmundsson, 2011]. In this study, we create a twin experiment to compare three different assimilation algorithms based on inverse methods and nudging to constrain the bedrock friction and the bedrock elevation: (i) cyclic inversion of friction parameter and bedrock topography using adjoint method, (ii) cycles coupling inversion of friction parameter using adjoint method and nudging of bedrock topography, (iii) one step inversion of both parameters with adjoint method. The three methods show a clear improvement in parameters knowledge leading to a significant reduction of flux divergence of the model before forecasting.

Climate change and Sea level rise: Potential impact on the coast of the Edremit Plain, NW Turkey.

NASA Astrophysics Data System (ADS)

Curebal, Isa; Efe, Recep; Soykan, Abdullah; Sonmez, Suleyman

2015-04-01

Over the past century, most of the world's mountain glaciers and the ice sheets have lost mass due to global warming. When the temperature exceeds a particular level, glaciers and polar ice caps will continue to lose mass. Recent studies report that low-lying coastal areas will be seriously affected by sea level rise. Changes in the amount of natural and anthropogenic greenhouse gases and aerosols had a warming effect on the global climate during last century. Thus, the pace of melting of ice sheets increased, and, accordingly, sea level began to rise faster. Rise in sea level between 1961 and 2003 was equal to 1.8 mm/year while it was 3.1 mm/year between 1993 and 2003. The total rise in the 20th century is estimated to be between 17 and 19 cm. The models based on the sea level change indicate that the average global temperature at the end of the 21st century will increase by 0.3°C - 6.4°C. Global sea level is projected to rise 8-25 cm by 2030, relative to 2000 levels, 18-48 cm by 2050, and 50-140 cm by 20110. The Edremit Plain lies between Mount Madra and the Kaz Mountains on the coast of Aegean Sea in NW Turkey. It is lowland with an area of 141 km2. The widest part of the plain is 16 km along the E - W direction. The N - S direction amounts to a width of 15 km. The plain is covered with alluvial deposits that settled in the Quaternary Period. The elevation ranges from 0 to 50 m a.s.l. in the plain. This study aims to determine how the low-lying coastal land areas of the Edremit Plain may be affected by possible changes in sea level. Elevation dataset is based on the digital elevation model (DEM) of Landsat ETM + satellite images. To that end, satellite images were used to draw the current coastline. Curves of 2.5, 5, and 10 m were drawn through the use of maps with a scale of 1/25.000. Later on, the areas of the fields between these points were calculated. Current estimates show that 2.5 m rise in sea level will cause sea water to cover an area of 8.6 km2 (%14.0), 5 m to 28.4 km2 (%21.2), and 10 m to 58.3 km2 (%41.2) on the coastal land. In such cases, a +2.5 m change will trigger the current coastline to regress by 1.3 km while a +5 m change will lead to 3.4 km, and a +10 m change will cause 5.2 km. As a result, residential, agricultural, and wetlands on the coastal land of the plain will be submerged by rising sea levels, leading to significant habitat loss and changes in the ecosystem. The creation of detailed elevation may reveal more clear effects of the changes in sea level. Key Words: Climate change, coastline, Edremit plain, global warming, sea level rise.

Properties of M components from currents measured at triggered lightning channel base

NASA Astrophysics Data System (ADS)

Thottappillil, Rajeev; Goldberg, Jon D.; Rakov, Vladimir A.; Uman, Martin A.; Fisher, Richard J.; Schnetzer, George H.

1995-12-01

Channel base currents from triggered lightning were measured at the NASA Kennedy Space Center, Florida, during summer 1990 and at Fort McClellan, Alabama, during summer 1991. An analysis of the return stroke data and overall continuing current data has been published by Fisher et al. [1993]. Here an analysis is given of the impulsive processes, called M components, that occur during the continuing current following return strokes. The 14 flashes analyzed contain 37 leader-return stroke sequences and 158 M components, both processes lowering negative charge from cloud to ground. Statistics are presented for the following M current pulse parameters: magnitude, rise time, duration, half-peak width, preceding continuing current level, M interval, elapsed time since the return stroke, and charge transferred by the M current pulse. A typical M component in triggered lightning is characterized by a more or less symmetrical current pulse having an amplitude of 100-200 A (2 orders of magnitude lower than that for a typical return stroke [Fisher et al., 1993]), a 10-90% rise time of 300-500 μs (3 orders of magnitude larger than that for a typical return stroke [Fisher et al., 1993]), and a charge transfer to ground of the order of 0.1 to 0.2 C (1 order of magnitude smaller than that for a typical subsequent return stroke pulse [Berger et al., 1975]). About one third of M components transferred charge greater than the minimum charge reported by Berger et al. [1975] for subsequent leader-return stroke sequences. No correlation was found between either the M charge or the magnitude of the M component current (the two are moderately correlated) and any other parameter considered. M current pulses occurring soon after the return stroke tend to have shorter rise times, shorter durations, and shorter M intervals than those which occur later. M current pulses were observed to be superimposed on continuing currents greater than 30 A or so, with one exception out of 140 cases, wherein the continuing current level was measured to be about 20 A. The first M component virtually always (one exception out of 34 cases) occurred within 4 ms of the return stroke. This relatively short separation time between return stroke and the first M component, coupled with the observation of Fisher et al. [1993] that continuing currents lasting longer than 10 ms never occur without M current pulses, implies that the M component is a necessary feature of the continuing current mode of charge transfer to ground.

Cosmological implications of quantum entanglement in the multiverse

NASA Astrophysics Data System (ADS)

Kanno, Sugumi

2015-12-01

We explore the cosmological implications of quantum entanglement between two causally disconnected universes in the multiverse. We first consider two causally separated de Sitter spaces with a state which is initially entangled. We derive the reduced density matrix of our universe and compute the spectrum of vacuum fluctuations. We then consider the same system with an initially non-entangled state. We find that due to quantum interference scale dependent modulations may enter the spectrum for the case of initially non-entangled state. This gives rise to the possibility that the existence of causally disconnected universes may be experimentally tested by analyzing correlators in detail.

The detailed characteristics of positive corona current pulses in the line-to-plane electrodes

NASA Astrophysics Data System (ADS)

Xuebao, LI; Dayong, LI; Qian, ZHANG; Yinfei, LI; Xiang, CUI; Tiebing, LU

2018-05-01

The corona current pulses generated by corona discharge are the sources of the radio interference from transmission lines and the detailed characteristics of the corona current pulses from conductor should be investigated in order to reveal their generation mechanism. In this paper, the line-to-plane electrodes are designed to measure and analyze the characteristics of corona current pulses from positive corona discharges. The influences of inter-electrode gap and line diameters on the detail characteristics of corona current pulses, such as pulse amplitude, rise time, duration time and repetition frequency, are carefully analyzed. The obtained results show that the pulse amplitude and the repetition frequency increase with the diameter of line electrode when the electric fields on the surface of line electrodes are same. With the increase of inter-electrode gap, the pulse amplitude and the repetition frequency first decrease and then turn to be stable, while the rise time first increases and finally turns to be stable. The distributions of electric field and space charges under the line electrodes are calculated, and the influences of inter-electrode gap and line electrode diameter on the experimental results are qualitatively explained.

Women in Community College Leadership Roles. ERIC Digest.

ERIC Educational Resources Information Center

Getskow, Veronica

At community colleges, women currently comprise approximately 20% of all chief executive officer (CEO) positions. The single most important source from which new community college CEO candidates are selected, however, is the pool of deans of instruction and since 21% of current deans are women, it is likely that these numbers will rise. Moreover,…

Development of the Circum-Antarctic Current

USGS Publications Warehouse

Kennett, J.P.; Houtz, R.E.; Andrews, P.B.; Edwards, A.R.; Gostin, V.A.; Hajos, M.; Hampton, M.A.; Jenkins, D.G.; Margolis, S.V.; Ovenshine, A.T.; Perch-Nielsen, K.

1974-01-01

Deep-sea drilling in the Southern Ocean south of Australia and New Zealand shows that the Circum-Antarctic Current developed about 30 million years ago in the middle to late Oligocene when final separation occurred between Antarctica and the continental Soulth Tasman Rise. Australia had commenced drifting northward from Antarctica 20 million years before this.

Regulation of Tool-Use within a Blended Course: Student Differences and Performance Effects

ERIC Educational Resources Information Center

Lust, Griet; Elen, Jan; Clarebout, Geraldine

2013-01-01

Given the rising popularity of content management systems (CMSs) in higher education, the current study investigates how students use tools in CMS supported courses. More specifically, the current study investigates how students regulate their tool-use throughout the course period by considering the moment tools are used. This temporal dimension…

Timing, predictors, and progress of third space fluid accumulation during preliminary phase fluid resuscitation in adult patients with dengue.

PubMed

Premaratna, R; Ragupathy, A; Miththinda, J K N D; de Silva, H J

2013-07-01

Fluid leakage remains the hallmark of dengue hemorrhagic fever (DHF). The applicability of currently recommended predictors of DHF for adults with dengue is questionable as these are based on studies conducted in children. One hundred and two adults with dengue were prospectively followed up to investigate whether home-based or hospital-based early phase fluid resuscitation has an impact on clinical and hematological parameters used for the diagnosis of early or critical phase fluid leakage. In the majority of subjects, third space fluid accumulation (TSFA) was detected on the fifth and sixth days of infection. The quantity and quality of fluids administered played no role in TSFA. A reduction in systolic blood pressure appeared to be more helpful than a reduction in pulse pressure in predicting fluid leakage. TSFA occurred with lower percentage rises in packed cell volume (PCV) than stated in the current recommendations. A rapid reduction in platelets, progressive reduction in white blood cells, percentage rises in Haemoglobin (Hb), and PCV, and rises in aspartate aminotransferase and alanine aminotransferase were observed in patients with TSFA and therefore with the development of severe illness. Clinicians should be aware of the limitations of currently recommended predictors of DHF in adult patients who are receiving fluid resuscitation. Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Is the social volcano still dormant? Trends in Chinese attitudes toward inequality.

PubMed

Whyte, Martin King; Im, Dong-Kyun

2014-11-01

Data from two China national surveys, in 2004 and 2009, focusing on popular attitudes toward current inequalities and mobility opportunities, are compared to examine two key questions: (1) Did the continued rise in income gaps and the impact within China of the global financial crisis lead to rising popular anger about the unfairness of current inequality patterns in 2009? and (2) Did the social contours of attitudes toward current inequalities shift over the five years between surveys? Through systematic comparisons of data from both surveys, we conclude that there is no general increase in anger about inequalities in the 2009 survey, and that the predictors of variations in these attitudes had changed relatively little, with the unexpectedly positive views of villagers still visible in 2009, although a bit muted. Trends in Chinese society between 2004 and 2009, and in the personal experience of survey respondents, are used to explain why popular acceptance of current inequalities remains widespread, despite continuing increases in China's income gaps. Copyright © 2014 Elsevier Inc. All rights reserved.

The Orinoco megadelta as a conservation target in the face of the ongoing and future sea level rise.

PubMed

Vegas-Vilarrúbia, T; Hernández, E; Rull, Valentí; Rull Vegas, Elisa

2015-05-15

Currently, risk assessments related to rising sea levels and the adoption of defensive or adaptive measures to counter these sea level increases are underway for densely populated deltas where economic losses might be important, especially in the developed world. However, many underpopulated deltas harbouring high biological and cultural diversity are also at risk but will most likely continue to be ignored as conservation targets. In this study, we explore the potential effects of erosion, inundation and salinisation on one of the world's comparatively underpopulated megadeltas, the Orinoco Delta. With a 1 m sea level rise expected to occur by 2100, several models predict a moderate erosion of the delta's shorelines, migration or loss of mangroves, general inundation of the delta with an accompanying submersion of wetlands, and an increase in the distance to which sea water intrudes into streams, resulting in harm to the freshwater biota and resources. The Warao people are the indigenous inhabitants of the Orinoco Delta and currently are subject to various socioeconomic stressors. Changes due to sea level rise will occur extremely rapidly and cause abrupt shifts in the Warao's traditional environments and resources, resulting in migrations and abandonment of their ancestral territories. However, evidence indicates that deltaic aggradation/accretion processes at the Orinoco delta due to allochthonous sediment input and vegetation growth could be elevating the surface of the land, keeping pace with the local sea level rise. Other underpopulated and large deltas of the world also may risk immeasurable biodiversity and cultural losses and should not be forgotten as important conservation targets. Copyright © 2015. Published by Elsevier B.V.

High temporal resolution modeling of the impact of rain, tides, and sea level rise on water table flooding in the Arch Creek basin, Miami-Dade County Florida USA.

PubMed

Sukop, Michael C; Rogers, Martina; Guannel, Greg; Infanti, Johnna M; Hagemann, Katherine

2018-03-01

Modeling of groundwater levels in a portion of the low-lying coastal Arch Creek basin in northern Miami-Dade County in Southeast Florida USA, which is subject to repetitive flooding, reveals that rain-induced short-term water table rises can be viewed as a primary driver of flooding events under current conditions. Areas below 0.9m North American Vertical Datum (NAVD) elevation are particularly vulnerable and areas below 1.5m NAVD are vulnerable to exceptionally large rainfall events. Long-term water table rise is evident in the groundwater data, and the rate appears to be consistent with local rates of sea level rise. Linear extrapolation of long-term observed groundwater levels to 2060 suggest roughly a doubling of the number of days when groundwater levels exceed 0.9m NAVD and a threefold increase in the number of days when levels exceed 1.5m NAVD. Projected sea level rise of 0.61m by 2060 together with increased rainfall lead to a model prediction of frequent groundwater-related flooding in areas<0.9m NAVD. However, current simulations do not consider the range of rainfall events that have led to water table elevations>1.5m NAVD and widespread flooding of the area in the past. Tidal fluctuations in the water table are predicted to be more pronounced within 600m of a tidally influenced water control structure that is hydrodynamically connected to Biscayne Bay. The inland influence of tidal fluctuations appears to increase with increased sea level, but the principal driver of high groundwater levels under the 2060 scenario conditions remains groundwater recharge due to rainfall events. Copyright © 2017 Elsevier B.V. All rights reserved.

Childhood conditions and current physical performance among non-institutionalized individuals aged 50+ in Israel.

PubMed

Weinstein, Galit

2016-12-01

Adverse socioeconomic conditions in childhood have been previously linked with high risk of various health conditions. However, the association with future physical function has been less studied. Hand grip strength and chair-rising time are objective measures of physical capability indicating current and future health outcomes. The aim of this study was to test the hypothesis that perceived socio-economic status in childhood is related to current measures of physical function, among Israeli participants of the Survey of Health, Ageing and Retirement in Europe project. The study included 2300 participants aged 50 years or older (mean age 68 ± 10; 56 % women). Generalized linear regression models were used to examine the associations of childhood wealth and number of books in residence with grip strength and time to complete five rises from a chair. Logistic regression models were used to assess the relationships between the early life conditions and the ability to perform the physical tests. Adjustment was made for current income or household wealth, and for demographic, anthropometric, health, and life-style measures. Being wealthy and having a large number of books at home in childhood was associated with a stronger hand grip and a better chair-rise test performance. These associations were more robust in women compared to men, and persisted after adjustment for potential covariates. In addition, childhood wealth and number of books were associated with lower risk of being unable to perform the tests. Thus, early-life programming may contribute to physical function indicators in mid- and late-life.

Combining urbanization and hydrodynamics data to evaluate sea level rise impacts on coastal water resources

NASA Astrophysics Data System (ADS)

Young, C. R.; Martin, J. B.

2016-02-01

Assessments of the potential for salt water intrusion due to sea level rise require consideration of both coastal hydrodynamic and human activity thresholds. In siliciclastic systems, sea level rise may cause salt intrusion to coastal aquifers at annual or decadal scales, whereas in karst systems salt intrudes at the tidal scalse. In both cases, human activity impacts the freshwater portion of the system by altering the water demand on the aquifer. We combine physicochemical and human activity data to evaluate impact of sea level rise on salt intrusion to siliclastic (Indian River Lagoon, Fl, USA) and karst (Puerto Morelos, Yucatan, Mexico) systems under different sea level rise rate scenarios. Two hydrodynamic modeling scenarios are considered; flux controlled and head controlled. Under a flux controlled system hydraulic head gradients remain constant during sea level rise while under a head controlled system hydraulic graidents diminish, allowing saltwater intrusion. Our model contains three key terms; aquifer recharge, groundwater discharge and hydraulic conductivity. Groundwater discharge and hydraulic conductivity were calculated based on high frequency (karst system) and decadal (siliciclastic system) field measurements. Aquifer recharge is defined as precipitation less evapotranspiration and water demand was evaluated based on urban planning data that provided the regional water demand. Water demand includes agricultural area, toursim, traffic patterns, garbage collection and total population. Water demand was initially estimated using a partial leaset squares regression based on these variables. Our model indicates that water demand depends most on agricultural area, which has changed significantly over the last 30 years. In both systems, additional water demand creates a head controlled scenario, thus increaseing the protential fo salt intrusion with projected sea level rise.

Wound care specialization: a proposal for a comprehensive fellowship program.

PubMed

Ennis, William J; Valdes, Wesley; Meneses, Patricio

2004-01-01

This article represents a process paper describing the development, at our facility, of a wound care fellowship that was scheduled to begin in July of 2003. The proposed program is in no way a finished product or our statement of how the program must be. This article is presented as a call to wound care professionals for input, criticism, guidance, and--we hope--adoption and acceptance of wound care fellowships in some format in the future. After many years of work in this field, it has become apparent that without medical specialization wound care will never rise from its current status of part-time avocation to full-time occupation. After a brief background and description of the present status of wound care education, an initial curriculum, program objectives, and clinical rotation schedule are presented. We look forward to the day when this program will have been replaced with a fully accredited, readily accepted, board-certifiable fellowship program with all the rights and responsibilities afforded the other medical specialties.

Bubble bursting at an interface

NASA Astrophysics Data System (ADS)

Kulkarni, Varun; Sajjad, Kumayl; Anand, Sushant; Fezzaa, Kamel

2017-11-01

Bubble bursting is crucial to understanding the life span of bubbles at an interface and more importantly the nature of interaction between the bulk liquid and the outside environment from the point of view of chemical and biological material transport. The dynamics of the bubble as it rises from inside the liquid bulk to its disappearance on the interface after bursting is an intriguing process, many aspects of which are still being explored. In our study, we make detailed high speed imaging measurements to examine carefully the hole initiation and growth in bursting bubbles that unearth some interesting features of the process. Previous analyses available in literature are revisited based on our novel experimental visualizations. Using a combination of experiments and theory we investigate the role of various forces during the rupturing process. This work aims to further our current knowledge of bubble dynamics at an interface with an aim of predicting better the bubble evolution from its growth to its eventual integration with the liquid bulk.

Social Movements in Brazil and their Educational Work

NASA Astrophysics Data System (ADS)

Ghanem, Elie

1998-03-01

Using a distinction first proposed by Alain Touraine between historic and social movements, Ghanem's review of grassroots initiatives in Brazil argues that, despite differences in composition and aims, movements such as the landless rural workers, indigenous groups, and the women's movement in Brazil have attempted to shift the current socioeconomic order toward a new equilibrium - a process that is, however, not yet complete. In Ghanem's view, these movements are best described as historic movements. Addressing their educational aims, the author finds that they tend to fall into two types: (1) the self-provision of knowledge related to the set of problems that gave rise to their movement in the first place; (2) the striving for access to knowledge that is due to them as citizens and yet not given to them by the state. Often, social movements in Brazil are obliged to offer educational services through their own resources, services which are characterized by precarious conditions and which make the right to quality education still a distant dream.

Wind Energy Deployment in Isolated Islanded Power Systems: Challenges & Realities (Poster)

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

Baring-Gould, I.

Rising costs of fuels, energy surety, and the carbon impacts of diesel fuel are driving remote and islanded communities dependent on diesel power generation to look for alternatives. Over the past few years, interest in using wind energy to reduce diesel fuel consumption has increased dramatically, potentially providing economic, environmental, social, and security benefits to the energy supply of isolated and islanded communities. However, the task of implementing such systems has remained elusive and subject to many cases of lower-than-expected performance. This poster describes the current status of integrating higher contribution wind technology into islanded power systems, the progress ofmore » recent initiatives implemented by the U.S. Department of Energy and Interior, and some of the lingering technical and commercial challenges. Operating experience from a number of power systems is described. The worldwide market for wind development in islanded communities (some of these supplying large domestic loads) provides a strong market niche for the wind industry, even in the midst of a slow global recovery.« less

Silicon content design of CrSiN films for good anti-corrosion and anti-wear performances in NaOH solution

NASA Astrophysics Data System (ADS)

Wang, Haixin; Ye, Yuwei; Wang, Chunting; Zhang, Guangan; Liu, Wei

2018-06-01

The CrSiN films with different silicon contents were fabricated by medium frequency magnetron sputtering. The 304L stainless steel and Si (1 0 0) wafer were used for substrate specimens. Film plasticity, corrosion and tribological behaviors in 0.1 M NaOH solution were systematically investigated. Results show that the plasticity of CrN film could be improved by the addition of silicon. During the corrosion test, with the increase of silicon content, the corrosion current density exhibited a descending trend and impedance presented a rising trend. The COF and wear rate of as-prepared CrSiN film initially decreased and then increased as the silicon content increased. The CrSiN film with 12.7 at.% Si exhibited the lowest COF of 0.04 and a wear rate of 6.746  ×  10‑8 mm3 Nm‑1 in 0.1 M NaOH solution.

THE LINAC LASER NOTCHER FOR THE FERMILAB BOOSTER

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

Johnson, David E,; Duel, Kevin; Gardner, Matthew

2016-09-27

In synchrotron machines, the beam extraction is accomplished by a combination of septa and kicker magnets which deflect the beam from an accelerator into another. Ideally the kicker field must rise/fall in between the beam bunches. However, in reality, an intentional beam-free time region (aka "notch") is created on the beam pulse to assure that the beam can be extracted with minimal losses. In the case of the Fermilab Booster, the notch is created in the ring near injection energy by the use of fast kickers which deposit the beam in a shielded collimation region within the accelerator tunnel. Withmore » increasing beam power it is desirable to create this notch at the lowest possible energy to minimize activation. The Fermilab Proton Improvement Plan (PIP) initiated an R&D project to build a laser system to create the notch within a linac beam pulse at 750 keV. This talk will describe the concept for the laser notcher and discuss our current status, commissioning results, and future plans.« less