Updated folate data in the Dutch Food Composition Database and implications for intake estimates

PubMed Central

Westenbrink, Susanne; Jansen-van der Vliet, Martine; van Rossum, Caroline

2012-01-01

Background and objective Nutrient values are influenced by the analytical method used. Food folate measured by high performance liquid chromatography (HPLC) or by microbiological assay (MA) yield different results, with in general higher results from MA than from HPLC. This leads to the question of how to deal with different analytical methods in compiling standardised and internationally comparable food composition databases? A recent inventory on folate in European food composition databases indicated that currently MA is more widely used than HPCL. Since older Dutch values are produced by HPLC and newer values by MA, analytical methods and procedures for compiling folate data in the Dutch Food Composition Database (NEVO) were reconsidered and folate values were updated. This article describes the impact of this revision of folate values in the NEVO database as well as the expected impact on the folate intake assessment in the Dutch National Food Consumption Survey (DNFCS). Design The folate values were revised by replacing HPLC with MA values from recent Dutch analyses. Previously MA folate values taken from foreign food composition tables had been recalculated to the HPLC level, assuming a 27% lower value from HPLC analyses. These recalculated values were replaced by the original MA values. Dutch HPLC and MA values were compared to each other. Folate intake was assessed for a subgroup within the DNFCS to estimate the impact of the update. Results In the updated NEVO database nearly all folate values were produced by MA or derived from MA values which resulted in an average increase of 24%. The median habitual folate intake in young children was increased by 11–15% using the updated folate values. Conclusion The current approach for folate in NEVO resulted in more transparency in data production and documentation and higher comparability among European databases. Results of food consumption surveys are expected to show higher folate intakes when using the updated values. PMID:22481900

H(-) ion source developments at the SNS.

PubMed

Welton, R F; Stockli, M P; Murray, S N; Pennisi, T R; Han, B; Kang, Y; Goulding, R H; Crisp, D W; Sparks, D O; Luciano, N P; Carmichael, J R; Carr, J

2008-02-01

The U.S. Spallation Neutron Source (SNS) will require substantially higher average and pulse H(-) beam currents than can be produced from conventional ion sources such as the base line SNS source. H(-) currents of 40-50 mA (SNS operations) and 70-100 mA (power upgrade project) with a rms emittance of 0.20-0.35pi mm mrad and a approximately 7% duty factor will be needed. We are therefore investigating several advanced ion source concepts based on rf plasma excitation. First, the performance characteristics of an external antenna source based on an Al(2)O(3) plasma chamber combined with an external multicusp magnetic configuration, an elemental Cs system, and plasma gun will be discussed. Second, the first plasma measurements of a helicon-driven H(-) ion source will also be presented.

H- ion source developments at the SNSa)

NASA Astrophysics Data System (ADS)

Welton, R. F.; Stockli, M. P.; Murray, S. N.; Pennisi, T. R.; Han, B.; Kang, Y.; Goulding, R. H.; Crisp, D. W.; Sparks, D. O.; Luciano, N. P.; Carmichael, J. R.; Carr, J.

2008-02-01

The U.S. Spallation Neutron Source (SNS) will require substantially higher average and pulse H- beam currents than can be produced from conventional ion sources such as the base line SNS source. H- currents of 40-50mA (SNS operations) and 70-100mA (power upgrade project) with a rms emittance of 0.20-0.35πmmmrad and a ˜7% duty factor will be needed. We are therefore investigating several advanced ion source concepts based on rf plasma excitation. First, the performance characteristics of an external antenna source based on an Al2O3 plasma chamber combined with an external multicusp magnetic configuration, an elemental Cs system, and plasma gun will be discussed. Second, the first plasma measurements of a helicon-driven H- ion source will also be presented.

Development and pilot line production of lithium doped silicon solar cells

NASA Technical Reports Server (NTRS)

Payne, P. A.

1972-01-01

Scaling up the BCl3 without O2 diffusion beyond 30 to 40 cells was investigated by using a 100 cell capacity diffusion boat which held the cells vertically. Sheet resistances and I-V curves were uniform with 10 to 20 cells spaced along the entire boat, so the quantity was increased to 40 and then 60 cells per diffusion. There was no change in cell output and uniformity going from 20 to 40 cells per diffusion; however only half the lithium cells fabricated from slices diffused in the 60 cell diffusion had efficiencies of 11% or better. Although uniform sheet resistances and I-V characteristic curves were obtained with up to 60 cells in the BCl3 with O2 diffusion, the short circuit currents were approximately 15% lower than the anticipated 135 to 140 mA. Consequently, work on this diffusion process has been aimed solely at increasing the short circuit current. The diffusion temperature was lowered from 1055 to 1000 and 950 C, and at each of these temperatures variations in diffusion time were investigated. At 1000 C short circuit currents were approximately 10 mA higher, 130 rather than 120 mA average.

Measurement of the neutrino neutral-current elastic differential cross section on mineral oil at Eν˜1GeV

NASA Astrophysics Data System (ADS)

Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J. M.; Cox, D. C.; Curioni, A.; Dharmapalan, R.; Djurcic, Z.; Finley, D. A.; Fleming, B. T.; Ford, R.; Garcia, F. G.; Garvey, G. T.; Grange, J.; Green, C.; Green, J. A.; Hart, T. L.; Hawker, E.; Imlay, R.; Johnson, R. A.; Karagiorgi, G.; Kasper, P.; Katori, T.; Kobilarcik, T.; Kourbanis, I.; Koutsoliotas, S.; Laird, E. M.; Linden, S. K.; Link, J. M.; Liu, Y.; Liu, Y.; Louis, W. C.; Mahn, K. B. M.; Marsh, W.; Mauger, C.; McGary, V. T.; McGregor, G.; Metcalf, W.; Meyers, P. D.; Mills, F.; Mills, G. B.; Monroe, J.; Moore, C. D.; Mousseau, J.; Nelson, R. H.; Nienaber, P.; Nowak, J. A.; Osmanov, B.; Ouedraogo, S.; Patterson, R. B.; Pavlovic, Z.; Perevalov, D.; Polly, C. C.; Prebys, E.; Raaf, J. L.; Ray, H.; Roe, B. P.; Russell, A. D.; Sandberg, V.; Schirato, R.; Schmitz, D.; Shaevitz, M. H.; Shoemaker, F. C.; Smith, D.; Soderberg, M.; Sorel, M.; Spentzouris, P.; Spitz, J.; Stancu, I.; Stefanski, R. J.; Sung, M.; Tanaka, H. A.; Tayloe, R.; Tzanov, M.; van de Water, R. G.; Wascko, M. O.; White, D. H.; Wilking, M. J.; Yang, H. J.; Zeller, G. P.; Zimmerman, E. D.

2010-11-01

We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH2) as a function of four-momentum transferred squared, Q2. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50 MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass MA that provides a best fit for MA=1.39±0.11GeV. Using the data from the charged-current neutrino interaction sample, a ratio of neutral-current to charged-current quasielastic cross sections as a function of Q2 has been measured. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at Q2=0, Δs, is found to be Δs=0.08±0.26.

Properties of model-averaged BMDLs: a study of model averaging in dichotomous response risk estimation.

PubMed

Wheeler, Matthew W; Bailer, A John

2007-06-01

Model averaging (MA) has been proposed as a method of accounting for model uncertainty in benchmark dose (BMD) estimation. The technique has been used to average BMD dose estimates derived from dichotomous dose-response experiments, microbial dose-response experiments, as well as observational epidemiological studies. While MA is a promising tool for the risk assessor, a previous study suggested that the simple strategy of averaging individual models' BMD lower limits did not yield interval estimators that met nominal coverage levels in certain situations, and this performance was very sensitive to the underlying model space chosen. We present a different, more computationally intensive, approach in which the BMD is estimated using the average dose-response model and the corresponding benchmark dose lower bound (BMDL) is computed by bootstrapping. This method is illustrated with TiO(2) dose-response rat lung cancer data, and then systematically studied through an extensive Monte Carlo simulation. The results of this study suggest that the MA-BMD, estimated using this technique, performs better, in terms of bias and coverage, than the previous MA methodology. Further, the MA-BMDL achieves nominal coverage in most cases, and is superior to picking the "best fitting model" when estimating the benchmark dose. Although these results show utility of MA for benchmark dose risk estimation, they continue to highlight the importance of choosing an adequate model space as well as proper model fit diagnostics.

Long-term variations of clay mineral composition in the Andaman Sea (IODP Exp. 353 Site U1447): preliminary result

NASA Astrophysics Data System (ADS)

Lee, J.; Khim, B. K.; Cho, H. G.; Kim, S.; 353 Scientists, I. E.

2016-12-01

Clay mineral studies in the Bengal Fan have allowed the reconstruction of the erosional history of the Himalayan-Tibetan complex since the Early Miocene. Several factors such as climate change and tectonic activity are important for the erosion rate of the Himalaya-Tibet complex. IODP Expedition 353 Site U1447 (10°47.4'N, 93°00'E; 1391 mbsl) was drilled on a ridge 45 km offshore Little Andaman Island in the Andaman Sea, penetrating to total depths of 738 m. Riverine sediments supplied mainly by the Irrawaddy and Salween (draining the Indo-Burman Ranges; smectite-rich) and the Ganga/Brahmaputra (draining the Himalaya; illite-rich) via the surface currents have been known to deposit in the Andaman Sea. We measured clay minerals of 38 sediment samples collected from 150 to 737 m CSF-A at Site U1447 in order to reveal long-term variation patterns of clay minerals and their controlling factors. Age reconstruction of Site U1447 aided by shipboard biostratigraphic and paleomagnetic data defined the study interval spanning from the Late Miocene ( 10 Ma) to Early Pleistocene ( 1.25 Ma). At this interval, clay minerals consist mainly of smectite (28-61% with an average of 47%) followed by illite (20-41% with an average of 29%), kaolinite (9-19% with an average of 14%), and chlorite (5-15% with an average of 10%). Variation of clay mineral compositions is divided into three stages; almost consistent variations of all clay minerals (from 750 to 570 m CSF-A; 10.0 to 7.5 Ma), gradual decrease of smectite and increase of illite and chlorite (from 570 to 400 m CSF-A; 7.5 to 4.5 Ma), and great fluctuation of all clay minerals (from 400 to 150 m CSF-A; 4.5 to 1.1 Ma). Such long-term clay mineral changes may be related to provenance switches, tectonic evolution of the source regions, climatic variations, degree of volcanism with basin evolution, sedimentation history by sea level changes or some combination of these factors.

Pediatric stroke and transcranial direct current stimulation: methods for rational individualized dose optimization

PubMed Central

Gillick, Bernadette T.; Kirton, Adam; Carmel, Jason B.; Minhas, Preet; Bikson, Marom

2014-01-01

Background: Transcranial direct current stimulation (tDCS) has been investigated mainly in adults and doses may not be appropriate in pediatric applications. In perinatal stroke where potential applications are promising, rational adaptation of dosage for children remains under investigation. Objective: Construct child-specific tDCS dosing parameters through case study within a perinatal stroke tDCS safety and feasibility trial. Methods: 10-year-old subject with a diagnosis of presumed perinatal ischemic stroke and hemiparesis was identified. T1 magnetic resonance imaging (MRI) scans used to derive computerized model for current flow and electrode positions. Workflow using modeling results and consideration of dosage in previous clinical trials was incorporated. Prior ad hoc adult montages vs. de novo optimized montages provided distinct risk benefit analysis. Approximating adult dose required consideration of changes in both peak brain current flow and distribution which further tradeoff between maximizing efficacy and adding safety factors. Electrode size, position, current intensity, compliance voltage, and duration were controlled independently in this process. Results: Brain electric fields modeled and compared to values previously predicted models (Datta et al., 2011; Minhas et al., 2012). Approximating conservative brain current flow patterns and intensities used in previous adult trials for comparable indications, the optimal current intensity established was 0.7 mA for 10 min with a tDCS C3/C4 montage. Specifically 0.7 mA produced comparable peak brain current intensity of an average adult receiving 1.0 mA. Electrode size of 5 × 7 cm2 with 1.0 mA and low-voltage tDCS was employed to maximize tolerability. Safety and feasibility confirmed with subject tolerating the session well and no serious adverse events. Conclusion: Rational approaches to dose customization, with steps informed by computational modeling, may improve guidance for pediatric stroke tDCS trials. PMID:25285077

Mechanisms of weak thickness dependence of the critical current density in strong-pinning ex situ metal organic-deposition-route YBa2Cu3O7-x coated conductors

NASA Astrophysics Data System (ADS)

Kim, S. I.; Gurevich, A.; Song, X.; Li, X.; Zhang, W.; Kodenkandath, T.; Rupich, M. W.; Holesinger, T. G.; Larbalestier, D. C.

2006-09-01

We report on the thickness dependence of the superconducting characteristics including critical current Ic, critical current density Jc, transition temperature Tc, irreversibility field Hirr, bulk pinning force plot Fp(H), and normal state resistivity curve ρ(T) measured after successive ion milling of ~1 µm thick high-Ic YBa2Cu3O7-x films made by an ex situ metal-organic deposition process on Ni-W rolling-assisted biaxially textured substrates (RABiTSTM). In contrast to many recent data, mostly on in situ pulsed laser deposition (PLD) films, which show strong depression of Jc with increasing film thickness t, our films exhibit only a weak dependence of Jc on t. The two better textured samples had full cross-section average Jc,avg (77 K, 0 T) ~4 MA cm-2 near the buffer layer interface and ~3 MA cm-2 at full thickness, despite significant current blocking due to ~30% porosity in the film. Taking account of the thickness dependence of the porosity, we estimate that the local, vortex-pinning current density is essentially independent of thickness, while accounting for the additional current-blocking effects of grain boundaries leads to local, vortex-pinning Jc values well above 5 MA cm-2. Such high local Jc values are produced by strong three-dimensional vortex pinning which subdivides vortex lines into weakly coupled segments much shorter than the film thickness.

Synthesis of thoria nano-particles at low temperature through base electrogeneration on steel 316L surface: Effect of current density

NASA Astrophysics Data System (ADS)

Yousefi, Taher; Torab-Mostaedi, Meisam; Mobtaker, Hossein Ghasemi; Keshtkar, Ali Reza

2016-10-01

The strategy developed in this study, offers significant advantages (simplicity and cleanness of method and also a product purity and new morphology of the product) over the conventional routes for the synthesis of ThO2 nanostructure. The effect of current density on morphology was studied. The synthesized powder was characterized by means of Powder X-ray Diffraction (PXRD), Transmission Electron Microscopy (TEM, Phillips EM 2085) Brunauer-Emmett-Teller (BET) and Fourier Transform Infrared (FT-IR) spectroscopy. The results show that the current density has a great effect on the morphology of the samples. The average size of the particles decreases as the applied current density increases and the average size of the samples decreases from 50 to 15 nm when the current density increases from 2 to 5 mA cm-2.

Bulk-Type All-Solid-State Lithium-Ion Batteries: Remarkable Performances of a Carbon Nanofiber-Supported MgH2 Composite Electrode.

PubMed

Zeng, Liang; Ichikawa, Takayuki; Kawahito, Koji; Miyaoka, Hiroki; Kojima, Yoshitsugu

2017-01-25

Magnesium hydride, MgH 2 , a recently developed compound for lithium-ion batteries, is considered to be a promising conversion-type negative electrode material due to its high theoretical lithium storage capacity of over 2000 mA h g -1 , suitable working potential, and relatively small volume expansion. Nevertheless, it suffers from unsatisfactory cyclability, poor reversibility, and slow kinetics in conventional nonaqueous electrolyte systems, which greatly limit the practical application of MgH 2 . In this work, a vapor-grown carbon nanofiber was used to enhance the electrical conductivity of MgH 2 using LiBH 4 as the solid-state electrolyte. It shows that a reversible capacity of over 1200 mA h g -1 with an average voltage of 0.5 V (vs Li/Li + ) can be obtained after 50 cycles at a current density of 1000 mA g -1 . In addition, the capacity of MgH 2 retains over 1100 mA h g -1 at a high current density of 8000 mA g -1 , which indicates the possibility of using MgH 2 as a negative electrode material for high power and high capacity lithium-ion batteries in future practical applications. Moreover, the widely studied sulfide-based solid electrolyte was also used to assemble battery cells with MgH 2 electrode in the same system, and the electrochemical performance was as good as that using LiBH 4 electrolyte.

42 CFR 422.252 - Terminology.

Code of Federal Regulations, 2012 CFR

2012-10-01

... supplemental benefit, as described at § 422.266(b)(1). MA-PD plan means an MA local or regional plan that...). MA monthly prescription drug beneficiary premium is the MA-PD plan base beneficiary premium, defined... and the national average bid (as described in § 422.256(c)) less the amount of rebate the MA-PD plan...

42 CFR 422.252 - Terminology.

Code of Federal Regulations, 2014 CFR

2014-10-01

... supplemental benefit, as described at § 422.266(b)(1). MA-PD plan means an MA local or regional plan that...). MA monthly prescription drug beneficiary premium is the MA-PD plan base beneficiary premium, defined... and the national average bid (as described in § 422.256(c)) less the amount of rebate the MA-PD plan...

42 CFR 422.252 - Terminology.

Code of Federal Regulations, 2013 CFR

2013-10-01

... supplemental benefit, as described at § 422.266(b)(1). MA-PD plan means an MA local or regional plan that...). MA monthly prescription drug beneficiary premium is the MA-PD plan base beneficiary premium, defined... and the national average bid (as described in § 422.256(c)) less the amount of rebate the MA-PD plan...

Safety parameter considerations of anodal transcranial Direct Current Stimulation in rats.

PubMed

Jackson, Mark P; Truong, Dennis; Brownlow, Milene L; Wagner, Jessica A; McKinley, R Andy; Bikson, Marom; Jankord, Ryan

2017-08-01

A commonly referenced transcranial Direct Current Stimulation (tDCS) safety threshold derives from tDCS lesion studies in the rat and relies on electrode current density (and related electrode charge density) to support clinical guidelines. Concerns about the role of polarity (e.g. anodal tDCS), sub-lesion threshold injury (e.g. neuroinflammatory processes), and role of electrode montage across rodent and human studies support further investigation into animal models of tDCS safety. Thirty-two anesthetized rats received anodal tDCS between 0 and 5mA for 60min through one of three epicranial electrode montages. Tissue damage was evaluated using hemotoxylin and eosin (H&E) staining, Iba-1 immunohistochemistry, and computational brain current density modeling. Brain lesion occurred after anodal tDCS at and above 0.5mA using a 25.0mm 2 electrode (electrode current density: 20.0A/m 2 ). Lesion initially occurred using smaller 10.6mm 2 or 5.3mm 2 electrodes at 0.25mA (23.5A/m 2 ) and 0.5mA (94.2A/m 2 ), respectively. Histological damage was correlated with computational brain current density predictions. Changes in microglial phenotype occurred in higher stimulation groups. Lesions were observed using anodal tDCS at an electrode current density of 20.0A/m 2 , which is below the previously reported safety threshold of 142.9A/m 2 using cathodal tDCS. The lesion area is not simply predicted by electrode current density (and so not by charge density as duration was fixed); rather computational modeling suggests average brain current density as a better predictor for anodal tDCS. Nonetheless, under the assumption that rodent epicranial stimulation is a hypersensitive model, an electrode current density of 20.0A/m 2 represents a conservative threshold for clinical tDCS, which typically uses an electrode current density of 2A/m 2 when electrodes are placed on the skin (resulting in a lower brain current density). Copyright © 2017 Elsevier Inc. All rights reserved.

Reaction time variability and related brain activity in methamphetamine psychosis.

PubMed

Fassbender, Catherine; Lesh, Tyler A; Ursu, Stefan; Salo, Ruth

2015-03-01

This study investigated the dynamics of cognitive control instability in methamphetamine (MA) abuse, as well its relationship to substance-induced psychiatric symptoms and drug use patterns. We used an ex-Gaussian reaction time (RT) distribution to examine intraindividual variability (IIV) and excessively long RTs (tau) in an individual's RT on a Stroop task in 30 currently drug-abstinent (3 months to 2 years) MA abusers compared with 27 nonsubstance-abusing control subjects. All subjects underwent functional magnetic resonance imaging while performing the Stroop task, which allowed us to measure the relationship between IIV and tau to functional brain activity. Elevated IIV in the MA compared with the control group did not reach significance; however, when the MA group was divided into those subjects who had experienced MA-induced psychosis (MAP+) (n = 19) and those who had not (n = 11), the MAP+ group had higher average IIV compared with the other groups (p < .03). In addition, although control subjects displayed a relationship between IIV and conflict-related brain activity in bilateral prefrontal cortex such that increased IIV was associated with increased activity, the MAP+ group displayed this relationship in right prefrontal cortex only, perhaps reflecting elevated vigilance in the MAP+ group. Greater IIV did not correlate with severity of use or months MA abstinent. No group differences emerged in tau values. These results suggest increased cognitive instability in those MA-dependent subjects who had experienced MA-induced psychosis. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

CT breast dose reduction with the use of breast positioning and organ-based tube current modulation.

PubMed

Fu, Wanyi; Tian, Xiaoyu; Sturgeon, Gregory M; Agasthya, Greeshma; Segars, William Paul; Goodsitt, Mitchell M; Kazerooni, Ella A; Samei, Ehsan

2017-02-01

This study aimed to investigate the breast dose reduction potential of a breast-positioning (BP) technique for thoracic CT examinations with organ-based tube current modulation (OTCM). This study included 13 female anthropomorphic computational phantoms (XCAT, age range: 27-65 y.o., weight range: 52-105.8 kg). Each phantom was modified to simulate three breast sizes in standard supine geometry. The modeled breasts were then morphed to emulate BP that constrained the majority of the breast tissue inside the 120° anterior tube current (mA) reduction zone. The OTCM mA value was modeled using a ray-tracing program, which reduced the mA to 20% in the anterior region with a corresponding increase to the posterior region. The organ doses were estimated by a validated Monte Carlo program for a typical clinical CT system (SOMATOM Definition Flash, Siemens Healthcare). The simulated organ doses and organ doses normalized by CTDI vol were used to compare three CT protocols: attenuation-based tube current modulation (ATCM), OTCM, and OTCM with BP (OTCM BP ). On average, compared to ATCM, OTCM reduced breast dose by 19.3 ± 4.5%, whereas OTCM BP reduced breast dose by 38.6 ± 8.1% (an additional 23.8 ± 9.4%). The dose saving of OTCM BP was more significant for larger breasts (on average 33, 38, and 44% reduction for 0.5, 1, and 2 kg breasts, respectively). Compared to ATCM, OTCM BP also reduced thymus and heart dose by 15.1 ± 7.4% and 15.9 ± 6.2% respectively. In thoracic CT examinations, OTCM with a breast-positioning technique can markedly reduce unnecessary exposure to radiosensitive organs in anterior chest wall, specifically breast tissue. The breast dose reduction is more notable for women with larger breasts. © 2016 American Association of Physicists in Medicine.

Texas Instruments-Digital Signal Processor(TI-DSP)SMJ320F20 SEL Testing

NASA Technical Reports Server (NTRS)

Sanders, Anthony B.; Poivey, C.; Kim, H. S.; Gee, George B.

2006-01-01

This viewgraph presentation reviews the testing of the Texas Instrument Digital Signal Processor(TI-DSP)SMJ320F20. Tests were performed to screen for susceptibility to Single Event Latchup (SEL) and measure sensitivity as a function of Linear Energy Transfer (LET) for an application specific test setup. The Heavy Ion Testing of two TI-DSP SMJ320F240 devices experienced Single Event Latchup (SEL) conditions at an LET of 1.8 MeV/(mg/square cm) The devices were exposed from a fluence of 1.76 x l0(exp 3) to 5.00 x 10(exp 6) particles/square cm of the Neon, Argon and Krypton ion beams. For DI(sub DD) an average latchup current occurred at about 700mA, which is a magnitude of 10 over the nominal current of 700mA.

A vacuum sealed high emission current and transmission efficiency carbon nanotube triode

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

Di, Yunsong; Jiangsu Key Laboratory of Optoelectronic Technology, Nanjing Normal University, Nanjing 210023; Wang, Qilong

A vacuum sealed carbon nanotubes (CNTs) triode with a concave and spoke-shaped Mo grid is presented. Due to the high aperture ratio of the grid, the emission current could be modulated at a relatively high electric field. Totally 75 mA emission current has been obtained from the CNTs cathode with the average applied field by the grid shifting from 8 to 13 V/μm. Whilst with the electron transmission efficiency of the grid over 56%, a remarkable high modulated current electron beam over 42 mA has been collected by the anode. Also contributed by the high aperture ration of the grid,more » desorbed gas molecules could flow away from the emission area rapidly when the triode has been operated at a relative high emission current, and finally collected by a vacion pump. The working pressure has been maintained at ∼1 × 10{sup −7} Torr, seldom spark phenomena occurred. Nearly perfect I-V curve and corresponding Fowler-Nordheim (FN) plot confirmed the accuracy of the measured data, and the emission current was long term stable and reproducible. Thusly, this kind of triode would be used as a high-power electron source.« less

Rural Medicare Advantage Market Dynamics and Quality: Historical Context and Current Implications.

PubMed

Kemper, Leah; Barker, Abigail R; Wilber, Lyndsey; McBride, Timothy D; Mueller, Keith

2016-07-01

Purpose. In this policy brief, we assess variation in Medicare’s star quality ratings of Medicare Advantage (MA) plans that are available to rural beneficiaries. Evidence from the recent Centers for Medicare & Medicaid Services (CMS) quality demonstration suggests that market dynamics, i.e., firms entering and exiting the MA marketplace, play a role in quality improvement. Therefore, we also discuss how market dynamics may impact the smaller and less wealthy populations that are characteristic of rural places. Key Data Findings. (1) Highly rated MA plans serving rural Medicare beneficiaries are more likely to be health maintenance organizations (HMOs) and local preferred provider organizations (PPOs), as opposed to regional PPOs. HMOs and local PPOs may be better able to improve their quality scores strategically in response to the bonus payment incentive due to existing internal monitoring mechanisms. (2) On average, the rural enrollment rate is lower in plans with higher quality scores (59 percent) than the corresponding urban rate (71 percent). This differential is likely due, in part, to lack of availability of highly rated plans in rural areas: 17.8 percent of rural counties lacked access to a plan with four or more (out of five) stars, while just 3.7 percent of urban counties lacked such access. (3) MA plans with high quality scores have been operating longer, on average, and have a lower percentage of rural counties within their contract service areas than plans with lower quality scores.

Zircon, titanite, and apatite (U-Th)/He ages and age-eU correlations from the Fennoscandian Shield, southern Sweden

NASA Astrophysics Data System (ADS)

Guenthner, William R.; Reiners, Peter W.; Drake, Henrik; Tillberg, Mikael

2017-07-01

Craton cores far from plate boundaries have traditionally been viewed as stable features that experience minimal vertical motion over 100-1000 Ma time scales. Here we show that the Fennoscandian Shield in southeastern Sweden experienced several episodes of burial and exhumation from 1800 Ma to the present. Apatite, titanite, and zircon (U-Th)/He ages from surface samples and drill cores constrain the long-term, low-temperature history of the Laxemar region. Single grain titanite and zircon (U-Th)/He ages are negatively correlated (104-838 Ma for zircon and 160-945 Ma for titanite) with effective uranium (eU = U + 0.235 × Th), a measurement proportional to radiation damage. Apatite ages are 102-258 Ma and are positively correlated with eU. These correlations are interpreted with damage-diffusivity models, and the modeled zircon He age-eU correlations constrain multiple episodes of heating and cooling from 1800 Ma to the present, which we interpret in the context of foreland basin systems related to the Neoproterozoic Sveconorwegian and Paleozoic Caledonian orogens. Inverse time-temperature models constrain an average burial temperature of 217°C during the Sveconorwegian, achieved between 944 Ma and 851 Ma, and 154°C during the Caledonian, achieved between 366 Ma and 224 Ma. Subsequent cooling to near-surface temperatures in both cases could be related to long-term exhumation caused by either postorogenic collapse or mantle dynamics related to the final assembly of Rodinia and Pangaea. Our titanite He age-eU correlations cannot currently be interpreted in the same fashion; however, this study represents one of the first examples of a damage-diffusivity relationship in this system, which deserves further research attention.

Variations in county-level costs between traditional medicare and medicare advantage have implications for premium support.

PubMed

Biles, Brian; Casillas, Giselle; Guterman, Stuart

2015-01-01

Concern about the future growth of Medicare spending has led some in Congress and elsewhere to promote converting Medicare to a "premium support" system. Under premium support, Medicare would provide a "defined contribution" to each Medicare beneficiary to purchase either a Medicare Advantage (MA)-type private health plan or the traditional Medicare public plan. To better understand the implications of such a shift, we compared the average costs per beneficiary of providing Medicare benefits at the county level for traditional Medicare and four types of MA plans. We found that the relative costs of Medicare Advantage and traditional Medicare varied greatly by MA plan type and by geographic location. The costs of health maintenance organization-type plans averaged 7 percent less than those of traditional Medicare, but the costs of the more loosely structured preferred provider organization and private fee-for-service plans averaged 12-18 percent more than those of traditional Medicare. In some counties MA plan costs averaged 28 percent less than costs in traditional Medicare, while in other counties MA plan costs averaged 26 percent more than traditional Medicare costs. Enactment of a Medicare premium-support proposal could trigger cost increases for beneficiaries participating in Medicare Advantage as well as those in traditional Medicare. Project HOPE—The People-to-People Health Foundation, Inc.

Ion Source Development at the SNS

NASA Astrophysics Data System (ADS)

Welton, R. F.; Stockli, M. P.; Murray, S. N.; Carr, J.; Carmichael, J.; Goulding, R. H.; Baity, F. W.

2007-08-01

The US Spallation Neutron Source (SNS) has recently begun producing neutrons and is currently on track to becoming a world-leading facility for material science based on neutron scattering. The facility is comprised of an H- ion source, a linear accelerator, an accumulator ring, a liquid-Hg target and a suite of neutron scattering instruments. Over the next several years the average H- current from the ion source will be increased in order to meet the baseline facility requirement of providing 1.4 MW of beam-power to the target and the SNS power upgrade power requirement of 2+ MW on target. Meeting the latter goal will require H- currents of 70-100 mA with an RMS emittance of 0.20-0.35 π mm mrad and a ˜7% duty-factor. To date, the RF-driven-multicusp SNS ion source has only been able to demonstrate sustained operation at 33 mA of beam current at a ˜7% duty-factor. This report details our efforts to develop variations of the current ion source which can meet these requirements. Designs and experimental results are presented for helicon plasma drivers, high-power external antennas, glow-discharge plasma guns and advanced Cs systems.

Application of ion thruster technology to a 30-cm multipole sputtering ion source

NASA Technical Reports Server (NTRS)

Robinson, R. S.; Kaufman, H. R.

1976-01-01

A 30-cm electron-bombardment ion source has been designed and fabricated for micromachining and sputtering applications. This source has a multipole magnetic field that employs permanent magnets between permeable pole pieces. An average ion current density of 1 ma/sq cm with 500-eV argon ions was selected as a design operating condition. The ion beam at this operating condition was uniform and well collimated, with an average variation of + or -5 percent over the center 20 cm of the beam at a distance up to 30 cm from the ion source.

Dual-protection of a graphene-sulfur composite by a compact graphene skin and an atomic layer deposited oxide coating for a lithium-sulfur battery

NASA Astrophysics Data System (ADS)

Yu, Mingpeng; Wang, Aiji; Tian, Fuyang; Song, Hongquan; Wang, Yinshu; Li, Chun; Hong, Jong-Dal; Shi, Gaoquan

2015-03-01

A reduced graphene oxide (rGO)-sulfur composite aerogel with a compact self-assembled rGO skin was further modified by an atomic layer deposition (ALD) of ZnO or MgO layer, and used as a free-standing electrode material of a lithium-sulfur (Li-S) battery. The rGO skin and ALD-oxide coating worked as natural and artificial barriers to constrain the polysulfides within the cathode region. As a result, the Li-S battery based on this electrode material exhibited superior cycling stability, good rate capability and high coulombic efficiency. Furthermore, ALD-ZnO coating was tested for performance improvement and found to be more effective than ALD-MgO coating. The ZnO modified G-S electrode with 55 wt% sulfur loading delivered a maximum discharge capacity of 998 mA h g-1 at a current density of 0.2 C. A high capacity of 846 mA h g-1 was achieved after charging/discharging for 100 cycles with a coulombic efficiency of over 92%. In the case of using LiNO3 as a shuttle inhibitor, this electrode showed an initial discharge capacity of 796 mA h g-1 and a capacity retention of 81% after 250 cycles at a current density of 1 C with an average coulombic efficiency higher than 99.7%.A reduced graphene oxide (rGO)-sulfur composite aerogel with a compact self-assembled rGO skin was further modified by an atomic layer deposition (ALD) of ZnO or MgO layer, and used as a free-standing electrode material of a lithium-sulfur (Li-S) battery. The rGO skin and ALD-oxide coating worked as natural and artificial barriers to constrain the polysulfides within the cathode region. As a result, the Li-S battery based on this electrode material exhibited superior cycling stability, good rate capability and high coulombic efficiency. Furthermore, ALD-ZnO coating was tested for performance improvement and found to be more effective than ALD-MgO coating. The ZnO modified G-S electrode with 55 wt% sulfur loading delivered a maximum discharge capacity of 998 mA h g-1 at a current density of 0.2 C. A high capacity of 846 mA h g-1 was achieved after charging/discharging for 100 cycles with a coulombic efficiency of over 92%. In the case of using LiNO3 as a shuttle inhibitor, this electrode showed an initial discharge capacity of 796 mA h g-1 and a capacity retention of 81% after 250 cycles at a current density of 1 C with an average coulombic efficiency higher than 99.7%. Electronic supplementary information (ESI) available: Procedures of ALD operation, supplementary figures and details of theoretical simulations. See DOI: 10.1039/c5nr00166h

Implementation and application of moving average as continuous analytical quality control instrument demonstrated for 24 routine chemistry assays.

PubMed

Rossum, Huub H van; Kemperman, Hans

2017-07-26

General application of a moving average (MA) as continuous analytical quality control (QC) for routine chemistry assays has failed due to lack of a simple method that allows optimization of MAs. A new method was applied to optimize the MA for routine chemistry and was evaluated in daily practice as continuous analytical QC instrument. MA procedures were optimized using an MA bias detection simulation procedure. Optimization was graphically supported by bias detection curves. Next, all optimal MA procedures that contributed to the quality assurance were run for 100 consecutive days and MA alarms generated during working hours were investigated. Optimized MA procedures were applied for 24 chemistry assays. During this evaluation, 303,871 MA values and 76 MA alarms were generated. Of all alarms, 54 (71%) were generated during office hours. Of these, 41 were further investigated and were caused by ion selective electrode (ISE) failure (1), calibration failure not detected by QC due to improper QC settings (1), possible bias (significant difference with the other analyzer) (10), non-human materials analyzed (2), extreme result(s) of a single patient (2), pre-analytical error (1), no cause identified (20), and no conclusion possible (4). MA was implemented in daily practice as a continuous QC instrument for 24 routine chemistry assays. In our setup when an MA alarm required follow-up, a manageable number of MA alarms was generated that resulted in valuable MA alarms. For the management of MA alarms, several applications/requirements in the MA management software will simplify the use of MA procedures.

Vibration energy harvester with sustainable power based on a single-crystal piezoelectric cantilever array.

PubMed

Kim, Moonkeun; Lee, Sang-Kyun; Ham, Yong-Hyun; Yang, Yil Suk; Kwon, Jong-Kee; Kwon, Kwang-Ho

2012-08-01

We designed and fabricated a bimorph cantilever array for sustainable power with an integrated Cu proof mass to obtain additional power and current. We fabricated a cantilever system using single-crystal piezoelectric material and compared the calculations for single and arrayed cantilevers to those obtained experimentally. The vibration energy harvester had resonant frequencies of 60.4 and 63.2 Hz for short and open circuits, respectively. The damping ratio and quality factor of the cantilever device were 0.012 and 41.66, respectively. The resonant frequency at maximum average power was 60.8 Hz. The current and highest average power of the harvester array were found to be 0.728 mA and 1.61 mW, respectively. The sustainable maximum power was obtained after slightly shifting the short-circuit frequency. In order to improve the current and power using an array of cantilevers, we also performed energy conversion experiments.

The two-dimensional to three-dimensional transition structures of ZnCo2O4 for the application of lithium-ion batteries

NASA Astrophysics Data System (ADS)

Jung, Mi-Hee

2018-01-01

We prepare the transition structure of ZnCo2O4 via transformation from two-dimensional (2D) nanosheets to three-dimensional (3D) microspheres with the solvothermal method. ZnCo2O4 nanocrystallites were produced from the reaction of zinc acetate and cobalt nitrate in the non-aqueous methanol solution. The oriented attachment of ZnCo2O4 nanocrystallites results in the formation of the 2D wrinkled-paper-like structure of ZnCo2O4. The 2D ZnCo2O4 nanosheet agglomerate spontaneously because there is no appropriate surfactant, and they have weak electrical double layers in the precursor solution. As the stacking of 2D ZnCo2O4 nanosheets increased, the aggregate of ZnCo2O4 nanosheet was transformed into the 3D ZnCo2O4 microspheres. The transition structure of the ZnCo2O4 was composed of the interconnected ZnCo2O4 nanoparticles, which results in a porous structure to accommodate the volume expansion of ZnCo2O4 structure during the charge process. The transition structure of ZnCo2O4 exhibits a remarkably high specific capacity and improved cycle performance. At a current density of 100 mA g-1, the transition structure of ZnCo2O4 exhibited excellent initial discharge specific capacity of 2094 mA h g-1. The discharge capacity maintain at 1296.91 mA h g-1 after 200 cycles. Even as current density reached to 2000 mA g-1, the average specific capacity still showed 606.88 mA hg-1.

Facile preparation of MnO2 nanorods and evaluation of their supercapacitive characteristics

NASA Astrophysics Data System (ADS)

Aghazadeh, Mustafa; Asadi, Maryam; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

2016-02-01

The first time pulsed base (OH-) electrogeneration to the cathodic electrodeposition of MnO2 in nitrate bath was applied and MnO2 nanorods were obtained. The deposition experiments were performed under a pulse current mode with typical on-times and off-times (ton = 10 ms and toff = 50 ms) and a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterization with XRD and FTIR revealed that the prepared MnO2 is composed of both α and γ phases. Morphological evaluations through SEM and TEM revealed that the prepared MnO2 contains nanorods of relative uniform structures (with an average diameter of 50 nm). The electrochemical measurements through cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures reveal an excellent capacitive behavior with specific capacitance values of 242, 167 and 98 F g-1 under the applied current densities of 2, 5 and 10 A g-1, respectively. Also, excellent long-term cycling stabilities of 94.8%, 89.1%, and 76.5% were observed after 1000 charge-discharge cycles at the current densities of 2, 5 and 10 A g-1.

Soda Consumption Among Methamphetamine Users in the U.S.: Impact on Oral Health

PubMed Central

Murphy, Debra A.; Harrell, Lauren; Fintzy, Rachel; Vitero, Steven; Gutierrez, Alexis; Shetty, Vivek

2014-01-01

Purpose Dental disease is associated with methamphetamine (MA) use, and partly attributed to excessive consumption of sugared sodas. Hence the purpose was to verify patterns of sugared soda intake and their relationship to oral health. Methods Detailed assessments with 541 MA users at two dental clinics were conducted. Assessment included a lifetime history of methamphetamine use, sugared soda consumption, and a dental exam. Results Subjects were predominantly male (80.8%; mean age 44.4 years), on average had used MA for 11.6 years, and drank an average of 35.3 sodas per month. Number of days of MA use over the past 30 days was significantly associated with soda consumption. Increased years of MA use was associated with the likelihood of users reporting less overall satisfaction with life because of their teeth, specifically difficulty eating, and dry mouth. This is the first study to show a statistically significant association between MA use and sugared soda consumption. Conclusions MA users’ consumption of sugared sodas is higher than the adult general population, and this is the first study to show a statistically significant association between MA use and sugared soda consumption. In addition, increased soda consumption was associated with more dental problems among MA users. PMID:26870851

A phantom-based JAFROC observer study of two CT reconstruction methods: the search for optimisation of lesion detection and effective dose

NASA Astrophysics Data System (ADS)

Thompson, John D.; Chakraborty, Dev P.; Szczepura, Katy; Vamvakas, Ioannis; Tootell, Andrew; Manning, David J.; Hogg, Peter

2015-03-01

Purpose: To investigate the dose saving potential of iterative reconstruction (IR) in a computed tomography (CT) examination of the thorax. Materials and Methods: An anthropomorphic chest phantom containing various configurations of simulated lesions (5, 8, 10 and 12mm; +100, -630 and -800 Hounsfield Units, HU) was imaged on a modern CT system over a tube current range (20, 40, 60 and 80mA). Images were reconstructed with (IR) and filtered back projection (FBP). An ATOM 701D (CIRS, Norfolk, VA) dosimetry phantom was used to measure organ dose. Effective dose was calculated. Eleven observers (15.11+/-8.75 years of experience) completed a free response study, localizing lesions in 544 single CT image slices. A modified jackknife alternative free-response receiver operating characteristic (JAFROC) analysis was completed to look for a significant effect of two factors: reconstruction method and tube current. Alpha was set at 0.05 to control the Type I error in this study. Results: For modified JAFROC analysis of reconstruction method there was no statistically significant difference in lesion detection performance between FBP and IR when figures-of-merit were averaged over tube current (F(1,10)=0.08, p = 0.789). For tube current analysis, significant differences were revealed between multiple pairs of tube current settings (F(3,10) = 16.96, p<0.001) when averaged over image reconstruction method. Conclusion: The free-response study suggests that lesion detection can be optimized at 40mA in this phantom model, a measured effective dose of 0.97mSv. In high-contrast regions the diagnostic value of IR, compared to FBP, is less clear.

Effects of dose reduction on multi-detector computed tomographic images in evaluating the maxilla and mandible for pre-surgical implant planning: a cadaveric study.

PubMed

Koizumi, Hiroshi; Sur, Jaideep; Seki, Kenji; Nakajima, Koh; Sano, Tsukasa; Okano, Tomohiro

2010-08-01

To assess effects of dose reduction on image quality in evaluating maxilla and mandible for pre-surgical implant planning using cadavers. Six cadavers were used for the study using multi-detector computed tomography (CT) operated at 120 kV and the variable tube current of 80, 40, 20 and 10 mA. A slice thickness of 0.625 mm and pitch 1 were used. Multi-planar images perpendicular and parallel to dentitions were created. The images were evaluated by five oral radiologists in terms of visibility of the anatomical landmarks including alveolar crest, mandibular canal, floors of the maxillary sinus and nasal cavity, contours/cortical layer of jaw bones and the details of trabecular bone. Observers were asked to determine the quality of the images in comparison with 80 mA images based on the criteria: excellent, good, fair or non-diagnostic. The average scores of all observers were calculated for each specimen in all exposure conditions. The 40 mA images could visualize such landmarks and were evaluated to be same or almost equivalent in quality to the 80 mA images. Even the 20 mA images could be accepted just for diagnostic purpose for implant with substantial deterioration of the image quality. The 10 mA images may not be accepted because of the obscured contour caused by image noise. Significant dose reduction by lowering mA can be utilized for pre-surgical implant planning in multi-detector CT.

3,4-Methylenedioxymethamphetamine (MDMA) abuse may cause oxidative stress and potential free radical damage.

PubMed

Zhou, Jun F; Chen, Peng; Zhou, Ye H; Zhang, Liang; Chen, Huai H

2003-05-01

To investigate whether 3,4-methylenedioxymethamphetamine abuse (MDMA abuse) may cause oxidative stress and potential free radical damage in the bodies of MDMA abusers (MA), and to explore the mechanisms by which MDMA abuse may be causing oxidative stress. One hundred and twenty MA and 120 healthy volunteers (HV) were enrolled in a random control study design, in which the level of lipoperoxide (LPO) in erythrocytes, and the levels of Vitamin C (VC), Vitamin E (VE) and beta-carotene (beta-CAR) in plasma as well as the activities of superoxide dismutase (SOD) and catalase (CAT) in erythrocytes were determined by spectrophotometric methods. Compared with the average values of the above biochemical parameters in the HV group, the average value of LPO in erythrocytes in the MA group was significantly increased (P < 0.0001), while the average values of VC, VE and beta-CAR in plasma as well as those of SOD and CAT in erythrocytes in the MA group were significantly decreased (P < 0.0001). The analysis of bivariate correlations suggested that with the increase of the MDMA abuse dose and the MDMA abuse duration, the level of LPO in erythrocytes in the MA was increased (P < 0.0001), while the levels of VC, VE and beta-CAR in plasma as well as the activities of SOD and CAT in erythrocytes in the MA were decreased (P < 0.0001). The findings in this study suggest that MDMA abuse may cause oxidative stress and potential free radical damage to MA.

Tree-level imputation techniques to estimate current plot-level attributes in the Pacific Northwest using paneled inventory data

Treesearch

Bianca Eskelson; Temesgen Hailemariam; Tara Barrett

2009-01-01

The Forest Inventory and Analysis program (FIA) of the US Forest Service conducts a nationwide annual inventory. One panel (20% or 10% of all plots in the eastern and western United States, respectively) is measured each year. The precision of the estimates for any given year from one panel is low, and the moving average (MA), which is considered to be the default...

Granger causality for state-space models

NASA Astrophysics Data System (ADS)

Barnett, Lionel; Seth, Anil K.

2015-04-01

Granger causality has long been a prominent method for inferring causal interactions between stochastic variables for a broad range of complex physical systems. However, it has been recognized that a moving average (MA) component in the data presents a serious confound to Granger causal analysis, as routinely performed via autoregressive (AR) modeling. We solve this problem by demonstrating that Granger causality may be calculated simply and efficiently from the parameters of a state-space (SS) model. Since SS models are equivalent to autoregressive moving average models, Granger causality estimated in this fashion is not degraded by the presence of a MA component. This is of particular significance when the data has been filtered, downsampled, observed with noise, or is a subprocess of a higher dimensional process, since all of these operations—commonplace in application domains as diverse as climate science, econometrics, and the neurosciences—induce a MA component. We show how Granger causality, conditional and unconditional, in both time and frequency domains, may be calculated directly from SS model parameters via solution of a discrete algebraic Riccati equation. Numerical simulations demonstrate that Granger causality estimators thus derived have greater statistical power and smaller bias than AR estimators. We also discuss how the SS approach facilitates relaxation of the assumptions of linearity, stationarity, and homoscedasticity underlying current AR methods, thus opening up potentially significant new areas of research in Granger causal analysis.

Slow Long-Term Erosion Rates of Banks Peninsula, New Zealand

NASA Astrophysics Data System (ADS)

Dudunake, T.; Nichols, K. K.; Pugsley, E.; Nelson, S.; Colton, J.

2017-12-01

Banks Peninsula, located south of Christchurch, New Zealand, is composed of a multi-aged complex of volcanic centers. The oldest, Lyttelton Volcano is 12 to 10 Ma, and 350 km3. The largest volcano, Akaroa Volcano, is 9 to 8 Ma and 1200 km3. Both of these volcanoes have large embayments (Lyttelton Harbour and Akaroa Harbour) that connect the central volcano (the location of the former volcanic summits) to the ocean. The other eruptive centers, Mt. Herbert ( 9.5 to 8 Ma) and Diamond Harbor (7 to 5.8 Ma), have not eroded to sea level. We used inferred original surfaces and present day topography to calculate the volume of rock eroded from river valleys draining the flanks of Lyttelton (n=11) and Akaroa (n=26) volcanoes and from the large embayments that penetrate the eroding Lyttelton (n=8) and Akaroa (n=25) volcanoes. We used the youngest age of the eruptions as the start of erosion (Lyttelton = 10 Ma and Akaroa = 8 Ma) to determine erosion rates. Preliminary data suggest average erosion rates of 8.2 ± 2.4 m/My (averaged over 10 Ma) on the flanks of Lyttelton Volcano and 12 ± 5.1 m/My (averaged over 8 Ma) on the flanks of Akaroa Volcano. Dating control and formation processes of Lyttelton Harbour and Akaroa Harbour are poorly constrained. The youngest lava flows, Diamond Harbor, are 5.7 Ma and flow into the Lyttelton Harbour embayment. Using endmembers of embayment age for Lyttelton Harbour (10 Ma to 5.7 Ma) the erosion rates range between 18 ± 5.8 m/My and 31 ± 10 m/My. Similarly, the hillslopes of Akaroa Harbour have slow erosion rates (based on endmember ages of 8 Ma and 5.7 Ma) and range between 22 ± 18 and 31 ± 25 m/My. Even the fastest erosion rates on Banks Peninsula are an order of magnitude slower than the erosion rates of other basalt volcanoes in the world's oceans. Using a similar methodology, Tahiti is eroding between 1200 and 2700 m/Ma (Hildenbrand et al., 2008). Other erosion rates, based on sediment yields and water chemistry for La Reunion (400 to 3000 m/Ma; Louvat and Allegre, 1997), Guadeloupe (400 to 1700 m/Ma; Ricci et al., 2014), and Martinique (800 m/Ma; Germa et al., 2010) are also significantly faster than erosion rates of Banks Peninsula.

Stable silicon/3D porous N-doped graphene composite for lithium-ion battery anodes with self-assembly

NASA Astrophysics Data System (ADS)

Tang, Xiaofu; Wen, Guangwu; Song, Yan

2018-04-01

We fabricate a novel 3D N-doped graphene/silicon composite for lithium-ion battery anodes, with Si nanoparticles uniformly dispersed and thoroughly embedded in the N-doped graphene matrix. The favorable structure of the composite results in a BET surface area and an average mesopore diameter of 189.2 m2 g-1 and 3.82 nm, respectively. The composite delivers reversible capacities as high as 1132 mA h g-1 after 100 cycles under a current of 5 A g-1 and 1017 mA h g-1 after 200 cycles at 1 A g-1, and exhibits an improved rate capability. The present approach shows promise for the preparation of other high-performance anode materials for lithium-ion batteries.

Develop and test fuel cell powered on site integrated total energy systems. Phase 3: Full-scale power plant development

NASA Technical Reports Server (NTRS)

Kaufman, A.; Olson, B.; Pudick, S.; Wang, C. L.; Werth, J.; Whelan, J. A.

1986-01-01

The third in a series of 4kW stacks, consisting of 24 cells of the 13 inch x 23 inch cell size, has been on test for about 1600 hours. This stack is similar to the first two stacks, which ran 7000 and 8400 hours, respectively. The present stack incorporates technology improvements relating to the electrolyte-matrix, the current-collector assembly, and a reduction in the number of cooling plates. Performance is currently averaging about 0.64 per cell at 161 mA sq cm.

Effects of chronic methamphetamine on psychomotor and cognitive functions and dopamine signaling in the brain.

PubMed

Thanos, Panayotis K; Kim, Ronald; Delis, Foteini; Rocco, Mark J; Cho, Jacob; Volkow, Nora D

2017-03-01

Methamphetamine (MA) studies in animals usually involve acute, binge, or short-term exposure to the drug. However, addicts take substantial amounts of MA for extended periods of time. Here we wished to study the effects of MA exposure on brain and behavior, using an animal model analogous to this pattern of MA intake. MA doses, 4 and 8mg/kg/day, were based on previously reported average daily freely available MA self-administration levels. We examined the effects of 16 week MA treatment on psychomotor and cognitive function in the rat using open field and novel object recognition tests and we studied the adaptations of the dopaminergic system, using in vitro and in vivo receptor imaging. We show that chronic MA treatment, at doses that correspond to the average daily freely available self-administration levels in the rat, disorganizes open field activity, impairs alert exploratory behavior and anxiety-like state, and downregulates dopamine transporter in the striatum. Under these treatment conditions, dopamine terminal functional integrity in the nucleus accumbens is also affected. In addition, lower dopamine D1 receptor binding density, and, to a smaller degree, lower dopamine D2 receptor binding density were observed. Potential mechanisms related to these alterations are discussed. Copyright © 2016. Published by Elsevier B.V.

Gender differences in socio-demographic and clinical characteristics of methamphetamine inpatients in a Chinese population.

PubMed

He, Jincai; Xie, Ying; Tao, Jingyan; Su, Hang; Wu, Wenxiu; Zou, Shengzhen; Zhang, Jiajia; Zhang, Jie; Zhang, Hailing; Yang, Xiaofei; Guo, Jun; Tang, Wei; Zhang, Feixue; Liu, Jiahong; Liu, Linjing; Chen, Yuanling; Wen, Na; Kosten, Thomas R; Zhang, Xiang Yang

2013-06-01

Over the past two decades, China has experienced a dramatic increase in methamphetamine (MA) abuse. This study examined gender-specific socio-demographic and clinical characteristics of MA use among Han Chinese, which has previously received little systematic study. This analysis described MA-related socio-demographic and clinical characteristics in a broad cross-sectional sample (n=1464; male/female=1185/279), and examined differences between males and females in MA use history, MA initiation, MA-related subjective feelings and behaviors, and withdrawal symptoms. Most MA abusers (about 72%) were young (in their 20s or 30s), with women being 5 years younger than men on average. More males (33.2%) were married than females (21.9%). The average body mass index (BMI) was significantly lower in this MA abuser sample compared to the age-matched healthy controls. Moreover, the BMI of females was significantly lower than that of males. The laboratory tests showed that the blood levels of glucose, cholesterol and triglyceride were all significantly higher in males than females. Females used MA at a younger age compared to males. The most frequent route of MA use was smoking (90.9%). Males were more likely to use another drug, and more likely to be hospitalized. However, many characteristics and behaviors of MA use are similar for males and females, including the route, the dose and duration of MA use, and relapse status. Although there were some male-female similarities in MA use parameters, significant differences do exist that may have implications for gender-specific research as well as for prevention and treatment strategies. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Rheology and Ages of Lava Flows on Arsia and Pavonis Mons, Mars

NASA Astrophysics Data System (ADS)

Hiesinger, Harald; Bartel, Nicole; Boas, Theresa; Reiss, Dennis; Pasckert, Jan H.; van der Bogert, Carolyn H.

2015-04-01

We performed a new study of young lava flows on Arsia and Pavonis Mons. Compared to our previous study of Arsia and Pavonis flows [1], we not only expanded on the number of flows (13 additional new flows at Arsia; six new flows at Pavonis), but we also derived absolute model ages (AMAs) based on crater size-frequency distribution (CSFD) measurements. On the basis of the current study, we find that the yield strengths of the studied lava flows on Arsia Mons vary between ~2.54 x 102 Pa and ~9.63 x 103 Pa. The effusion rates are on average ~563 m3s-1. The calculated eruption durations range from three days to ~142 days with an average of ~32 days. The viscosities of the lava flows on Arsia Mons are on average ~2.54 x 106 Pa-s and vary between ~1.32 x 104 and ~2.88 x 107 Pa-s. The study also revealed an average yield strength of the Pavonis flows of ~3.56 x 103 Pa, ranging from ~2.5 x 102 to ~8.6 x 103 Pa. The effusion rates range from ~ 60 m3s-1 to ~309 m3s-1, with an average value of ~197 m3s-1. The investigated flows are characterized by an eruption duration in the range of ~3 to ~41 days, averaging about 15 days. The viscosities vary between ~2.8 x 104 Pa-s and ~7.6 x 106 Pa-s, with an average value of ~1.77 x 106 Pa-s. The new CSFD measurements for the Arsia flows yielded AMAs between ~36 and ~857 Ma. One unit shows an underlying older age of ~2.50 Ga and evidence for a resurfacing event at ~857 Ma. These ages are similar to those presented by [2-4] for the caldera of Arsia Mons, i.e., ~100-200 Ma. In addition, [4] argued that their ages represent the latest stages of summit and flank eruptions and that earlier episodes stopped at about 500 Ma, 800 Ma, and 2 Ga ago. Previously, we performed the first study that correlated rheologic properties and AMAs of lava flows on Elysium Mons [5]. We reported that the yield strengths of 32 investigated Elysium flows are on the order of ~3.0 x 103 Pa, ranging from ~3.8 x 102 to ~1.5 x 104 Pa. The effusion rates of the flows range from ~99 to ~4450 m3s-1, averaging at ~747 m3s-1. The lava flows were emplaced in less than a week (very small flows) to up to half a year (~6-183 days). Viscosities were calculated to be on average ~4.1 x 102 Pa-s, with a range of ~1.2 x 105 to ~3.1 x 107 Pa-s. The AMAs of the Elysium flows range from ~632 to ~3460 Ma [5]. Lava flows on both Arsia and Elysium Mons do not show any systematic correlations between the rheologic properties and model ages. In particular, neither yield strength and effusion rate, nor viscosity seems to be correlated with the AMA. Thus, the rheology of the studied flows did not change over several hundreds of million years. Preliminary results for Pavonis flows also do not show systematic changes of the rheology with time. [1] Hiesinger et al. (2008) LPSC 39, 1277. [2] Neukum et al. (2004) Nature 432, 971-979. [3] Robbins et al. (2011) Icarus 211, 1179-1203. [4] Werner (2009) Icarus 201, 44-68. [5] Pasckert et al. (2012) Icarus 219, 443-457.

Quantifying denudation of the West African passive-transform margin: implications for Cenozoic erosion budget of cratons and source-to-sink systems

NASA Astrophysics Data System (ADS)

Grimaud, Jean-Louis; Chardon, Dominique; Rouby, Delphine; Beauvais, Anicet

2014-05-01

We develop an approach based on the differential elevation of dated successive topographies of the onshore part of the West African margin to calibrate in-situ volumetric denudation over a 3.9 million km2 cratonic surface for the past 45 Ma. We obtain a regionally averaged volumetric erosion rate of 5 x 10-3 km3/km2/m.y. corresponding to a total average denudation of 300 m and a denudation rate of 6 m/m.y., which remained nearly constant over the three time spans (45- 24, 24-11 and 11-0 Ma) despite spatial variations related to epeirogenic movements. Denudation is converted into a minimum yield of 12 +/- 2 t/km2/yr with a minimum solute component of 4 +/- 2 t/km2/yr accounting for the porosity of the eroded regoliths. Our results would imply a minimum contribution of 1.6 +/- 0.4 Gt/yr of the non-orogenic landmass to the global continental yield since the last peak greenhouse. Reconstruction of two incision stages of West Africa landscape from the reconstructed topographies combined with paleogeographic data shows that the current river catchments of the sub region have acquired their current configuration by the end of the Oligocene at the latest (24 Ma ago). The fairly steady geometry of the West African drainage since then offers the opportunity to effectively link the inland geomorphic record to offshore sedimentation. Volumetric denudation analysis applied to West African sub-drainage areas attests to the role of drainage reorganization and epeirogenic mouvements (flexural growth of the marginal upwarp and amplification of the Hoggar intraplate swell) on the spatial and temporal distribution of continental denudation and yield. Onshore denudation and clastic sediments accumulation in the post-24 Ma Niger catchment - delta system are within the same order of magnitude. These results suggest that cratonic-type erosion fluxes estimated from the West African margin may be used to estimate the size of drainage basins from the fossil sedimentary record.

Field-Aligned Currents in Saturn's Magnetosphere: Observations From the F-Ring Orbits

NASA Astrophysics Data System (ADS)

Hunt, G. J.; Provan, G.; Bunce, E. J.; Cowley, S. W. H.; Dougherty, M. K.; Southwood, D. J.

2018-05-01

We investigate the azimuthal magnetic field signatures associated with high-latitude field-aligned currents observed during Cassini's F-ring orbits (October 2016-April 2017). The overall ionospheric meridional current profiles in the northern and southern hemispheres, that is, the regions poleward and equatorward of the field-aligned currents, differ most from the 2008 observations. We discuss these differences in terms of the seasonal change between data sets and local time (LT) differences, as the 2008 data cover the nightside while the F-ring data cover the post-dawn and dusk sectors in the northern and southern hemispheres, respectively. The F-ring field-aligned currents typically have a similar four current sheet structure to those in 2008. We investigate the properties of the current sheets and show that the field-aligned currents in a hemisphere are modulated by that hemisphere's "planetary period oscillation" (PPO) systems. We separate the PPO-independent and PPO-related currents in both hemispheres using their opposite symmetry. The average PPO-independent currents peak at 1.5 MA/rad just equatorward of the open closed field line boundary, similar to the 2008 observations. However, the PPO-related currents in both hemispheres are reduced by 50% to 0.4 MA/rad. This may be evidence of reduced PPO amplitudes, similar to the previously observed weaker equatorial oscillations at similar dayside LTs. We do not detect the PPO current systems' interhemispheric component, likely a result of the weaker PPO-related currents and their closure within the magnetosphere. We also do not detect previously proposed lower latitude discrete field-aligned currents that act to "turn off" the PPOs.

Benzene exposure monitoring of Tunisian workers.

PubMed

Chakroun, Radhouane; Kaabachi, Néziha; Hedhili, Abderrazek; Feki, Moncef; Nouaigui, Habib; Ben Laiba, Mohamed; Mebazaa, Abderraouf

2002-12-01

To monitor benzene exposure and to check reliability of urinary trans,trans-Muconic Acid (t,t-MA) as a bio-marker of benzene exposure in local conditions, a study was conducted on 30 Tunisian exposed workers (20 tanker fillers and 10 filling station attendants). The analyses were carried out on environmental air and urinary t,t-MA before (t,t-MAA) and at the end of work shift (t,t-MAB). 20 nonoccupationally exposed subjects were also investigated. The average value of environmental benzene concentration was 0.17 ppm. The differences between t,t-MAA and t,t-MAB concentrations and between t,t-MAB and t,t-MA measured in controls (t,t-MAC) were both significant (p < 0.001). Benzene air concentrations were well correlated with t,t-MAB: R = 0.76. In the nonexposed group, average t,t-MA concentrations is significantly higher among smokers than nonsmokers (P < 0.02). Analysis of urinary t,t-MA offers a relatively simple and suitable method for benzene exposure monitoring.

Monitoring tectonic uplift and paleoenvironmental reconstruction for marine terraces near Maǧaracik and Samandaǧ, Hatay Province, Turkey.

PubMed

Florentin, Jonathan A; Blackwell, Bonnie A B; Tüysüz, Okan; Tarı, Ufuk; Can Genç, Ş; İmren, Caner; Mo, Shirley; Huang, Yiwen E W; Blickstein, Joel I B; Skinner, Anne R; Kim, Maria

2014-06-01

Near Hatay, the Antakya-Samandağ-Cyprus Fault (ASCF), East Anatolian and Dead Sea Fault Zones, the large faults that form the edges of the African, Anatolian, Cyprus and Arabian Plates, all produce large earthquakes, which have decimated Hatay repeatedly. Near Samandağ, Hatay, differential vertical displacement on the ASCF has uplifted the southeastern side relative to northwestern side, producing large fault scarps that parallel the Asi (Orontes) River. Tectonic uplift coupled with Quaternary sealevel fluctuations has produced several stacked marine terraces stranded above current sealevel. This study dated 24 mollusc samples from 10 outcrops on six marine terraces near Samandağ electron spin resonance (ESR). Ages were calculated using time-averaged and volumetrically averaged external dose rates, modelled by assuming typical water depths for the individual species and sediment thicknesses estimated from geological criteria. Uplift rates were then calculated for each fault block. At all the Mağaracık terraces, the dates suggest that many shells were likely reworked. On the 30 m terrace at Mağaracık IV (UTM 766588-3999880), Lithophagus burrows with in situ shells cross the unconformity. One such shell dated to 62 ± 6 ka, setting the minimum possible age for the terrace. For all the Mağaracık terraces at ∼30 m above mean sealevel (amsl), the youngest ages for the reworked shells, which averaged 60 ± 3 ka for six separate analyses, sets the maximum possible age for this unit. Thus, the terrace must date to 60-62 ± 3 ka, at the MIS 3/4 boundary when temperatures and sealevels were fluctuating rapidly. Older units dating to MIS 7, 6, and 5 likely were being eroded to supply some fossils found in this terrace. At Mağaracık Dump (UTM 765391-4001048), ∼103 m amsl, Ostrea and other shells were found cemented in growth position to the limestone boulders outcropping there <2.0 m above a wave-eroded notch. If the oysters grew at the same time as the wave-cut notch and the related terrace, the date, 91 ± 13 ka, for the oysters, this fault block has been uplifted at 1.19 ± 0.15 m ky(-1), since MIS 5c. At Samandağ Kurt Stream at 38 m amsl, molluscs were deposited fine sandy gravel, which was likely formed in a large tidal channel. Four molluscs averaged 116 ± 5 ka. If these molluscs have not been reworked, this fault block has uplifted at 0.34 ± 0.05 m ky(-1) since the MIS 5d/5e boundary. The differences in these uplift rates suggests that at least one, and possibly two, hitherto undiscovered faults may separate the Mağaracık Dump site from the other Mağaracık sites and from the Samandağ Kurt Stream site. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Thermocathode radio-frequency gun for the Budker Institute of Nuclear Physics free-electron laser

NASA Astrophysics Data System (ADS)

Volkov, V.; Getmanov, Ya.; Kenjebulatov, E.; Kolobanov, E.; Krutikhin, S.; Kurkin, G.; Ovchar, V.; Petrov, V. M.; Sedlyarov, I.

2016-12-01

A radio-frequency (RF) gun for a race-track microtron-recuperator injector driving the free-electron laser (FEL) (Budker Institute of Nuclear Physics) is being tested at a special stand. Electron bunches of the RF gun have an energy of up to 300 keV and a repetition rate of up to 90 MHz. The average electro-beam current can reach 100 mA in the continuous operation regime. The advantages of the new injector are as follows: long lifetime of the cathode for high average beam current; simple scheme of longitudinal beam bunching, which does not require an additional bunching resonator in the injector; absence of dark-current contamination of the injector beam; and comfortable RF gun operation due to the absence of a high potential of 300 kV at the cathode control circuits. In this study we describe the RF gun design, present the main characteristics of the injector with the RF gun, and give the results of testing.

Terrigenous provenance follows climate variability at IODP Site U1474, southwestern Indian Ocean

NASA Astrophysics Data System (ADS)

Babin, D. P.; Hemming, S. R.; Simon, M.; Hall, I. R.; Franzese, A. M.; Goldstein, S. L.; Cai, Y.; Liu, T.; Johns, M. A.; Tejada, L.; LeVay, L.

2017-12-01

International Ocean Discovery Program (IODP) Expedition 361 `South African Climates' sought records to document the role of the greater Agulhas Current system in global climate variability and southeast African hydroclimate over the past 5 Ma. IODP Site U1474 is located at the headwaters of the fully constituted Agulhas Current. Being close to the southeast African margin, the core location is ideally situated to track variations of terrigenous sediment delivery to the site, which may relate to climatic changes in southern Africa that follow variability in the Agulhas Current heat content. To analyze climate variability, we consider an XRF record for the site in combination with major and trace element chemistry and K-Ar ages from the clay fraction (<2um) plus bulk major element chemistry of 60 shipboard moisture and density samples spanning 4.8 Ma. These data are interpreted with a sea surface temperature (SST) record from Mg/Ca measurements spaced at 40 kyr on the surface dwelling (mixed layer) planktonic foraminifera Globigerinoides ruber. Both long-term trend and precessionally-paced changes in the terrigenous composition are evident. Fe/K ratios from XRF core scanning data are consistent with those previously reported (Simon et al. 2015 Sci. Reports) in a nearby core that spans the last 270 ka. Terrigenous mass accumulation rates are relatively constant at 3 g/cm3/ky from 5-2.5 Ma, then gradually decrease to 2 g/cm3/ky at the top. This declining flux is accompanied by older and more weathered and mafic sources, possibly a result of reduced precipitation in proximal catchments. It is suggested that the relationships between these proxies is explained by a greater relative contribution of sediment supplied from the Limpopo catchment compared to nearby drainage basins such as the Tugela. The SST record shows a cooling trend from the 27 °C average between 4.5-2.5 Ma to 25 °C at 1.0 Ma, followed by high amplitude changes (6 °C changes instead of °3 C) in SST in the 0-1.0 Ma interval, with minimum SST estimates of 21 °C. These changes are consistent with, but could lag behind models predicting aridification in Africa associated with a drop in Indian Ocean temperatures around 3-4 Ma, caused by tectonic changes in the Indonesian Throughflow that shifted its Pacific source waters further north (Cane & Molnar 2001 Science).

Paying Medicare Advantage Plans: To Level or Tilt the Playing Field

PubMed Central

Glazer, Jacob; McGuire, Thomas G.

2017-01-01

Medicare beneficiaries are eligible for health insurance through the public option of traditional Medicare (TM) or may join a private Medicare Advantage (MA) plan. Both are highly subsidized but in different ways. Medicare pays for most of costs directly in TM, and makes a subsidy payment to an MA plan based on a “benchmark” for each beneficiary choosing a private plan. The level of this benchmark is arguably the most important policy decision Medicare makes about the MA program. Presently, about 30% of beneficiaries are in MA, and Medicare subsidizes MA plans more on average than TM. Many analysts recommend equalizing Medicare’s subsidy across the options – referred to in policy circles as a “level playing field.” This paper studies the normative question of how to set the level of the benchmark, applying the versatile model of plan choice developed by Einav and Finkelstein (EF) to Medicare. The EF framework implies unequal subsidies to counteract risk selection across plan types. We also study other reasons to tilt the field: the relative efficiency of MA vs. TM, market power of MA plans, and institutional features of the way Medicare determines subsidies and premiums. After review of the empirical and policy literature, we conclude that in areas where the MA market is competitive, the benchmark should be set below average costs in TM, but in areas characterized by imperfect competition in MA, it should be raised in order to offset output (enrollment) restrictions by plans with market power. We also recommend specific modifications of Medicare rules to make demand for MA more price elastic. PMID:28318667

Dual-protection of a graphene-sulfur composite by a compact graphene skin and an atomic layer deposited oxide coating for a lithium-sulfur battery.

PubMed

Yu, Mingpeng; Wang, Aiji; Tian, Fuyang; Song, Hongquan; Wang, Yinshu; Li, Chun; Hong, Jong-Dal; Shi, Gaoquan

2015-03-12

A reduced graphene oxide (rGO)-sulfur composite aerogel with a compact self-assembled rGO skin was further modified by an atomic layer deposition (ALD) of ZnO or MgO layer, and used as a free-standing electrode material of a lithium-sulfur (Li-S) battery. The rGO skin and ALD-oxide coating worked as natural and artificial barriers to constrain the polysulfides within the cathode region. As a result, the Li-S battery based on this electrode material exhibited superior cycling stability, good rate capability and high coulombic efficiency. Furthermore, ALD-ZnO coating was tested for performance improvement and found to be more effective than ALD-MgO coating. The ZnO modified G-S electrode with 55 wt% sulfur loading delivered a maximum discharge capacity of 998 mA h g(-1) at a current density of 0.2 C. A high capacity of 846 mA h g(-1) was achieved after charging/discharging for 100 cycles with a coulombic efficiency of over 92%. In the case of using LiNO3 as a shuttle inhibitor, this electrode showed an initial discharge capacity of 796 mA h g(-1) and a capacity retention of 81% after 250 cycles at a current density of 1 C with an average coulombic efficiency higher than 99.7%.

Urinary trans,trans-muconic acid as an indicator of exposure to benzene in cigarette smokers.

PubMed

Melikian, A A; Prahalad, A K; Hoffmann, D

1993-01-01

Epidemiological studies have shown an association between cigarette smoking and increased risk of myeloid leukemia in smokers. In evaluating this link it is important to note that cigarette smoke contains benzene, among other carcinogens. Since chronic benzene, among other carcinogens. Since chronic benzene exposure causes acute myeloid leukemia in humans, we aimed to determine the uptake and metabolic activation of benzene from cigarette smoke in smokers by measuring the levels of the urinary benzene metabolite, trans,trans-muconic acid (t,t-MA). The method used involved a clean-up procedure, followed by high-performance liquid chromatography with UV detection. The levels of urinary t,t-MA ranged from 0.02 to 1.3 mg/g creatinine, resulting in a mean of 0.29 +/- 0.04 mg/g creatinine in 42 male smokers, and corresponding values in nonsmokers ranged from "nondetectable" to 0.52 mg/g creatinine with an average of 0.09 +/- 0.02 mg/g creatinine. In the current study, the levels of t,t-MA in smokers were about 3 times higher than those in nonsmokers (P = 0.0001), and a significant correlation between concentration of t,t-MA and levels of cotinine in smokers was observed (r = 0.55; P = 0.0001; 95% confidence interval, 0.30-0.93), suggesting that urinary t,t-MA can be utilized as a biochemical marker to quantitate benzene exposure due to cigarette smoking.

Electrochemical preparation of MnO2 nanobelts through pulse base-electrogeneration and evaluation of their electrochemical performance

NASA Astrophysics Data System (ADS)

Aghazadeh, Mustafa; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

2016-02-01

Cathodic electrodeposition of MnO2 from a nitrate solution, via pulsed base (OH-) electrogeneration was performed for the first time. The deposition experiments were performed in a pulse current mode in typical on-times and off-times (i.e. ton = 1 s and toff = 1 s) with a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterizations conducted by XRD and FTIR techniques revealed that the prepared MnO2 is composed of both α and γ phases. Morphological observation by SEM and TEM showed that the prepared MnO2 is made up of nanobelts with uniform shapes (an average diameter and length of 50 nm and 1 μm, respectively). Further electrochemical measurements by cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures have excellent capacitive behaviors, like a specific capacitance of 235.5 F g-1 and capacity retention of 91.3% after 1000 cycling at the scan rate of 25 mV s-1.

Use and abuse of crustal accretion calculations

NASA Astrophysics Data System (ADS)

Pallister, John S.; Cole, James C.; Stoeser, Douglas B.; Quick, James E.

1990-01-01

Recent attempts to calculate the average growth rate of continental crust for the Late Proterozoic shield of Arabia and Nubia are subject to large geological uncertainties, and widely contrasting conclusions result from dissimilar boundary conditions. The four greatest sources of divergence are (1) the extent of 620-920 Ma arc-terrane crust beneath Phanerozoic cover; (2) the extent of pre-920 Ma continental crust within the arc terranes; (3) the amount of postaccretion magmatic addition and erosion; and (4) the aggregate length and average life span of Late Proterozoic magmatic-arc systems that formed the Arabian-Nubian Shield. Calculations restricted to the relatively well known Arabian segment of the Arabian-Nubian Shield result in average crustal growth rates and arc accretion rates comparable to rates for modern arc systems, but we recognize substantial uncertainty in such results. Critical review of available geochemical, isotopic, and geochronological evidence contradicts the often stated notion that intact, pre-920 Ma crust is widespread in the eastern Arabian Shield. Instead, the arc terranes of the region apparently were "contaminated" with sediments derived, in part, from pre-920 Ma crust. Available geologic and radiometric data indicate that the Arabian-Nubian Shield and its "Pan-African" extensions constitute the greatest known volume of arc-accreted crust on Earth that formed in the period 920-620 Ma. Thus, the region may truly represent a disproportionate share of Earth's crustal growth budget for this time period.

Self-Reported Chemotherapy-Related Cognitive Impairment Compared with Cognitive Complaints following Menopause.

PubMed

Vega, Jennifer N; Dumas, Julie; Newhouse, Paul

2018-06-15

Cancer-related cognitive impairment (CRCI) is commonly reported following the administration of cancer treatment. Current longitudinal studies, primarily in women with breast cancer, suggest that up to 35%-60% of patients exhibit persistent CRCI (pCRCI) following completion of chemotherapy. Complaints of subjective cognitive decline (SCD) are also commonly reported by women during and following the menopause transition in non-cancer patients. Although the majority of evidence for cognitive difficulties in cancer patients and survivors is attributed to chemotherapy, there is growing evidence to suggest that menopausal status can also influence cognitive function in cancer patients. Given that menopausal status may be contributing to pCRCI, we compared a group of primarily post-menopausal women with pCRCI to two groups of post-menopausal women: women who endorse menopause-associated SCD (maSCD+) and women who do not (maSCD-) to explore the similarities/differences between maSCD and pCRCI and the potential role of menopause in pCRCI. pCRCI participants report more severe SCD symptoms than women after natural menopause, despite being on average 2.5-years post-chemotherapy, supporting previous findings that CRCI can persist for months to years after completing treatment. pCRCI participants not only endorsed greater SCD, but also exhibited objective performance differences. In addition, pCRCI participants endorsed significantly greater menopausal symptoms compared to either maSCD group. Results were not related to menopausal status prior to chemotherapy or current endocrine therapy use. These results suggest that while menopausal symptoms may contribute to SCD experienced by cancer patients after chemotherapy, they do not fully account for pCRCI. This article is protected by copyright. All rights reserved.

Carbon-based coating containing ultrafine MoO2 nanoparticles as an integrated anode for high-performance lithium-ion batteries

NASA Astrophysics Data System (ADS)

Li, Quanyi; Yang, Qi; Zhao, Yanhong; Wan, Bin

2017-10-01

Copper-supported MoO2-C composite as an integrated anode with excellent battery performance was synthesized by a facile knife coating technique followed by heat treatment in a vacuum. The obtained samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermal analysis, nitrogen adsorption and desorption analysis, field emission scanning microscopy (FESEM), and transmission electron microscopy (TEM). The results show the MoO2-C composite coating is comprised of a porous carbon matrix with a pore size of 1-3 nm and ultrafine MoO2 nanoparticles with a size of 5-10 nm encapsulated inside, the coating is tightly attached on the surface of copper foil, and the interface between them is free of cracks. Stable PAN-DMF-H2O system containing ammonium molybdate suitable for knife coating technique and the MoO2-C composite with ultrafine MoO2 nanoparticles encapsulated in the carbon matrix can be prepared through controlling amount of added ammonium molybdate solution. The copper-supported MoO2-C composite coating can be directly utilized as the integrated anode for lithium-ion batteries (LIBs). It delivers a capacity of 814 mA h g-1 at a current density of 100 mA g-1 after 100 cycles without apparent capacity fading. Furthermore, with increase of current densities to 200, 500, 1000, 2000, and 5000 mA g-1, it exhibits average capacities of 809, 697, 568, 383, and 188 mA h g-1. Its outstanding electrochemical performance is attributed to combined merits of integrated anode and structure with ultrafine MoO2 nanoparticles embedded in the porous carbon matrix.

Minimally Invasive Exposure of the Maxillary Artery at the Anteromedial Infratemporal Fossa.

PubMed

Rodriguez Rubio, Roberto; Kola, Olivia; Tayebi Meybodi, Ali; Tabani, Halima; Feng, Xuequan; Burkhardt, Jan-Karl; Yousef, Sonia; Lawton, Michael T; Benet, Arnau

2018-04-12

The maxillary artery (MA) has been described as a reliable donor for extracranial-intracranial high-flow bypass. Existing techniques to harvest MA require brain retraction and drilling of the middle fossa (with or without a zygomatic osteotomy), carrying the potential risks of venous bleeding, injury to the branches of the maxillary or mandibular nerves, muscular transection, or temporomandibular junction disorders. To describe a novel technique to expose the MA without bony drilling and with minimal impact to surrounding structures. A conventional curvilinear incision was performed in 10 cadaveric specimens, prior to elevating the scalp to expose the zygomatic root and lateral orbital rim. The sphenozygomatic suture was followed to the anterolateral edge of the inferior orbital fissure (IOF) to locate and harvest the pterygoid segment of the MA. Topographic anatomy was assessed using surrounding landmarks and 3D Cartesian coordinates to define the surgical area. The number of visible MA branches and their lengths were recorded. The MA was successfully exposed in all specimens. This approach allowed 6 branches of MA to be exposed. The average length of exposure was 23.3 ± 8.3 mm and the average surgical area was 2.8 ± 0.9 cm2. The IOF was 11.5 ± 4.2 mm from the MA. Our technique provides landmarks to identify the distal pterygoid segment of MA as a donor for extracranial-intracranial bypasses without the need for additional craniectomies. Clear anatomical landmarks, including the sphenozygomatic suture, anterolateral edge of IOF, infraorbital artery, and the pterygomaxillary fissure defined a trajectory to efficiently localize the MA with minimal risk to surrounding structures.

Comparison of interpretation methods of thermocouple psychrometer readouts

NASA Astrophysics Data System (ADS)

Guz, Łukasz; Majerek, Dariusz; Sobczuk, Henryk; Guz, Ewa; Połednik, Bernard

2017-07-01

Thermocouple psychrometers allow to determine the water potential, which can be easily recalculated into relative humidity of air in cavity of porous materials. The available typical measuring range of probe is very narrow. The lower limit of water potential measurements is about -200 kPa. On the other hand, the upper limit is approximately equal to -7000 kPa and depends on many factors. These paper presents a comparison of two interpretation methods of thermocouple microvolt output regarding: i) amplitude of voltage during wet-bulb temperature depression, ii) field under microvolt output curve. Previous results of experiments indicate that there is a robust correlation between water potential and field under microvolt output curve. In order to obtain correct results of water potential, each probe should be calibrated. The range of NaCl salt solutions with molality from 0.75M to 2.25M was used for calibration, which enable to obtain the osmotic potential from -3377 kPa to -10865 kPa. During measurements was applied 5mA heating current over a span 5 s and 5 mA cooling current aver a span 30s. The conducted study proves that using only different interpretation method based on field under microvolt output it is possible to achieve about 1000 kPa wider range of water potential. The average relative mean square error (RMSE) of this interpretation method is 1199 kPa while voltage amplitude based method yields average RMSE equaling 1378 kPa during calibration in temperature not stabilized conditions.

Analysis of coupled-bunch instabilities for the NSLS-II storage ring with a 500MHz 7-cell PETRA-III cavity

DOE PAGES

Bassi, G.; Blednykh, A.; Cheng, W.; ...

2015-12-11

We present the NSLS-II storage ring that is designed to operate with superconducting RF-cavities with the aim to store an average current of 500 mA distributed in 1080 bunches, with a gap in the uniform filling for ion clearing. At the early stage of the commissioning (phase 1), characterized by a bare lattice without damping wigglers and without Landau cavities, a normal conducting 7-cell PETRA-III RF-cavity structure has been installed with the goal to store an average current of 25 mA. In this paper we discuss our analysis of coupled-bunch instabilities driven by the Higher Order Modes (HOMs) of themore » 7-cell PETRA-III RF-cavity. As a cure of the instabilities, we apply a well-known scheme based on a proper detuning of the HOMs frequencies based upon cavity temperature change, and the use of the beneficial effect of the slow head–tail damping at positive chromaticity to increase the transverse coupled-bunch instability thresholds. In addition, we discuss measurements of coupled-bunch instabilities observed during the phase 1 commissioning of the NSLS-II storage ring. In our analysis we rely, in the longitudinal case, on the theory of coupled-bunch instability for uniform fillings, while in the transverse case we complement our studies with numerical simulations with OASIS, a novel parallel particle tracking code for self-consistent simulations of collective effects driven by short and long-range wakefields.« less

SDSS IV MaNGA - Properties of AGN Host Galaxies

NASA Astrophysics Data System (ADS)

Sánchez, S. F.; Avila-Reese, V.; Hernandez-Toledo, H.; Cortes-Suárez, E.; Rodríguez-Puebla, A.; Ibarra-Medel, H.; Cano-Díaz, M.; Barrera-Ballesteros, J. K.; Negrete, C. A.; Calette, A. R.; de Lorenzo-Cáceres, A.; Ortega-Minakata, R. A.; Aquino, E.; Valenzuela, O.; Clemente, J. C.; Storchi-Bergmann, T.; Riffel, R.; Schimoia, J.; Riffel, R. A.; Rembold, S. B.; Brownstein, J. R.; Pan, K.; Yates, R.; Mallmann, N.; Bitsakis, T.

2018-04-01

We present the characterization of the main properties of a sample of 98 AGN host galaxies, both type-II and type-I, in comparison with those of ≍2700 non-active galaxies observed by the MaNGA survey. We found that AGN hosts are morphologically early-type or early-spirals. AGN hosts are, on average, more massive, more compact, more centrally peaked and more pressure-supported systems. They are located in the intermediate/transition region between starforming and non-star-forming galaxies (i.e., the so-called green valley). We consider that they are in the process of halting/quenching the star formation. The analysis of the radial distributions of different properties shows that the quenching happens from inside-out involving both a decrease of the effciency of the star formation and a deficit of molecular gas. The data-products of the current analysis are distributed as a Value Added Catalog within the SDSS-DR14.

How Successful Is Medicare Advantage?

PubMed Central

Newhouse, Joseph P; McGuire, Thomas G

2014-01-01

Context Medicare Part C, or Medicare Advantage (MA), now almost 30 years old, has generally been viewed as a policy disappointment. Enrollment has vacillated but has never come close to the penetration of managed care plans in the commercial insurance market or in Medicaid, and because of payment policy decisions and selection, the MA program is viewed as having added to cost rather than saving funds for the Medicare program. Recent changes in Medicare policy, including improved risk adjustment, however, may have changed this picture. Methods This article summarizes findings from our group's work evaluating MA's recent performance and investigating payment options for improving its performance even more. We studied the behavior of both beneficiaries and plans, as well as the effects of Medicare policy. Findings Beneficiaries make “mistakes” in their choice of MA plan options that can be explained by behavioral economics. Few beneficiaries make an active choice after they enroll in Medicare. The high prevalence of “zero-premium” plans signals inefficiency in plan design and in the market's functioning. That is, Medicare premium policies interfere with economically efficient choices. The adverse selection problem, in which healthier, lower-cost beneficiaries tend to join MA, appears much diminished. The available measures, while limited, suggest that, on average, MA plans offer care of equal or higher quality and for less cost than traditional Medicare (TM). In counties, greater MA penetration appears to improve TM's performance. Conclusions Medicare policies regarding lock-in provisions and risk adjustment that were adopted in the mid-2000s have mitigated the adverse selection problem previously plaguing MA. On average, MA plans appear to offer higher value than TM, and positive spillovers from MA into TM imply that reimbursement should not necessarily be neutral. Policy changes in Medicare that reform the way that beneficiaries are charged for MA plan membership are warranted to move more beneficiaries into MA. PMID:24890251

How successful is Medicare Advantage?

PubMed

Newhouse, Joseph P; McGuire, Thomas G

2014-06-01

Medicare Part C, or Medicare Advantage (MA), now almost 30 years old, has generally been viewed as a policy disappointment. Enrollment has vacillated but has never come close to the penetration of managed care plans in the commercial insurance market or in Medicaid, and because of payment policy decisions and selection, the MA program is viewed as having added to cost rather than saving funds for the Medicare program. Recent changes in Medicare policy, including improved risk adjustment, however, may have changed this picture. This article summarizes findings from our group's work evaluating MA's recent performance and investigating payment options for improving its performance even more. We studied the behavior of both beneficiaries and plans, as well as the effects of Medicare policy. Beneficiaries make "mistakes" in their choice of MA plan options that can be explained by behavioral economics. Few beneficiaries make an active choice after they enroll in Medicare. The high prevalence of "zero-premium" plans signals inefficiency in plan design and in the market's functioning. That is, Medicare premium policies interfere with economically efficient choices. The adverse selection problem, in which healthier, lower-cost beneficiaries tend to join MA, appears much diminished. The available measures, while limited, suggest that, on average, MA plans offer care of equal or higher quality and for less cost than traditional Medicare (TM). In counties, greater MA penetration appears to improve TM's performance. Medicare policies regarding lock-in provisions and risk adjustment that were adopted in the mid-2000s have mitigated the adverse selection problem previously plaguing MA. On average, MA plans appear to offer higher value than TM, and positive spillovers from MA into TM imply that reimbursement should not necessarily be neutral. Policy changes in Medicare that reform the way that beneficiaries are charged for MA plan membership are warranted to move more beneficiaries into MA. © 2014 Milbank Memorial Fund.

Do Medicare Advantage Plans Select Enrollees in Higher Margin Clinical Categories?

PubMed Central

Newhouse, Joseph P.; McWilliams, J. Michael; Price, Mary; Huang, Jie; Fireman, Bruce; Hsu, John

2013-01-01

The CMS-HCC risk adjustment system for Medicare Advantage (MA) plans calculates weights, which are effectively relative prices, for beneficiaries with different observable characteristics. To do so it uses the relative amounts spent per beneficiary with those characteristics in Traditional Medicare (TM). For multiple reasons one might expect relative amounts in MA to differ from TM, thereby making some beneficiaries more profitable to treat than others. Much of the difference comes from differences in how TM and MA treat different diseases or diagnoses. Using data on actual medical spending from two MA-HMO plans, we show that the weights calculated from MA costs do indeed differ from those calculated using TM spending. One of the two plans (Plan 1) is more typical of MA-HMO plans in that it contracts with independent community providers, while the other (Plan 2) is vertically integrated with care delivery. We calculate margins, or Average Revenue/Average Cost, for Medicare beneficiaries in the two plans who have one of 48 different combinations of medical conditions. The two plans’ margins for these 48 conditions are correlated (r=0.39, p<0.01). Both plans have margins that are more positive for persons with conditions that are managed by primary care physicians and where medical management can be effective. Conversely they have lower margins for persons with conditions that tend to be treated by specialists with greater market power than primary care physicians and for acute conditions where little medical management is possible. The two plan’s margins among beneficiaries with different observable characteristics vary over a range of 160 and 98 percentage points, respectively, and thus would appear to offer substantial incentive for selection by HCC. Nonetheless, we find no evidence of overrepresentation of beneficiaries in high margin HCC’s in either plan. Nor, using the margins from Plan 1, the more typical plan, do we find evidence of overrepresentation of high margin HCC’s in Medicare more generally. These results do not permit a conclusion on overall social efficiency, but we note that selection according to margin could be socially efficient. In addition, our findings suggest there are omitted interaction terms in the risk adjustment model that Medicare currently uses. PMID:24308879

Industrial ion source technology

NASA Technical Reports Server (NTRS)

Kaufman, H. R.

1976-01-01

A 30 cm electron bombardment ion source was designed and fabricated for micromachining and sputtering applications. This source has a multipole magnetic field that employs permanent magnets between permeable pole pieces. An average ion current density of 1 ma/sq cm with 500 eV argon ions was selected as a design operating condition. The ion beam at this operating condition was uniform and well collimated, with an average variation of plus or minus 5 percent over the center 20 cm of the beam at distances up to 30 cm from the ion source. A variety of sputtering applications were undertaken with a small 10 cm ion source to better understand the ion source requirements in these applications. The results of these experimental studies are also included.

Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis.

PubMed

Carlos-Bregni, Román; Contreras, Elisa; Netto, Ana Carolina; Mosqueda-Taylor, Adalberto; Vargas, Pablo Agustin; Jorge, Jacks; León, Jorge Esquiche; de Almeida, Oslei Paes

2007-09-01

Oral melanoacanthoma (MA) is a rare, benign pigmented lesion, similar to cutaneous MA, characterized by hyperplasia of spinous keratinocytes and dendritic melanocytes. The pathogenesis of oral MA remains uncertain, although its clinical behavior is suggestive of a reactive origin. The most common intraoral sites are the buccal mucosa, lip, palate and gingiva. The average age of presentation is 28 years, mainly in blacks, with a strong female predilection. The oral melanotic macule (MM) is a small, well-circumscribed brown-to-black macule that occurs on the lips and mucous membranes. The etiology is not clear and it may represent a physiologic or reactive process. The average age of presentation is 43 years, with a female predilection. A biopsy is recommended to distinguish these lesions from each other and from other oral melanocytic lesions. We depict four cases each of oral MA and MM, affecting Caucasian and Latin American mestizo patients. The clinicopathological features of these cases reflect its ample spectrum, and to the best of our knowledge, it is the first example of oral MA affecting a Caucasian boy reported in the English literature. Therefore oral MA and MM should be considered in the differential diagnosis of pigmented lesions in the oral mucosa in these populations.

JPSS-1 VIIRS Version 2 At-Launch Relative Spectral Response Characterization and Performance

NASA Technical Reports Server (NTRS)

Moeller, Chris; Schwarting, Thomas; McIntire, Jeff; Moyer, Dave; Zeng, Jinan

2017-01-01

The relative spectral response (RSR) characterization of the JPSS-1 VIIRS spectral bands has achieved at launch status in the VIIRS Data Analysis Working Group February 2016 Version 2 RSR release. The Version 2 release improves upon the June 2015 Version 1 release by including December 2014 NIST TSIRCUS spectral measurements of VIIRS VisNIR bands in the analysis plus correcting CO2 influence on the band M13 RSR. The T-SIRCUS based characterization is merged with the summer 2014 SpMA based characterization of VisNIR bands (Version 1 release) to yield a fused RSR for these bands, combining the strengths of the T-SIRCUS and the SpMA measurement systems. The M13 RSR is updated by applying a model-based correction to mitigate CO2 attenuation of the SpMA source signal that occurred during M13 spectral measurements. The Version 2 release carries forward the Version 1 RSR for those bands that were not updated (M8-M12, M14-M16AB, I3-I5, DNBMGS). The Version 2 release includes band average (overall detectors and subsamples) RSR plus supporting RSR for each detector and subsample. The at-launch band average RSR have been used to populate Look-Up Tables supporting the sensor data record and environmental data record at-launch science products. Spectral performance metrics show that JPSS-1VIIRS RSR are compliant on specifications with a few minor exceptions. The Version 2 release, which replaces the Version 1 release, is currently available on the password-protected NASA JPSS-1 eRooms under EAR99 control.

Petrogenesis of Sveconorwegian magmatism in southwest Norway; constraints from zircon U-Pb-Hf-O and whole-rock geochemistry

NASA Astrophysics Data System (ADS)

Roberts, Nick M. W.; Slagstad, Trond; Parrish, Randall R.; Norry, Michael J.; Marker, Mogens; Horstwood, Matthew S. A.; Røhr, Torkil

2013-04-01

The Sveconorwegian orogen is traditionally interpreted as a Himalayan-scale continental collision, and the eastward continuation of the Grenville Province of Laurentia; however, it has recently been proposed that it represents an accretionary orogen without full-scale continental collision (Slagstad et al., in press). We suggest that magmatism is one of the key constraints to differentiate between different types of orogens; thus, detailed investigation of the timing and petrogenesis of the magmatic record is a requirement for better understanding of the Sveconorwegian orogen as a whole. Here, we present new U-Pb geochronology, zircon Hf-O isotope, and whole-rock geochemical data to constrain the petrogenesis of the early -Sveconorwegian Sirdal Magmatic Belt (SMB). The SMB is a batholithic-scale complex of intrusions that intrudes into most of the Rogaland-Hardangervidda Block in southwest Norway. Current age constraints put emplacement between ~1050 to 1020 Ma. New ages from the Suldal region indicate that the onset of SMB magmatism can be put back to 1070 Ma, which is some 30-50 Myrs prior to high-grade metamorphism. Average initial ɛHf signatures range from ~0 to 4; these overlap with later post-Sveconorwegian granites and with early-/pre-Sveconorwegian ferroan (A-type) granites. Average δ18O signatures range from ~5.7 to 8.7, except for one anomalous granite at ~11.6. The Hf-O signatures are compatible with a mixed mantle-crustal source. Crustal sources may include ~1500 Ma Telemarkian or ~1200 Ma juvenile crust. Hf-O bulk-mixing modelling using a 1500 Ma crustal source indicates >50 % mantle input. Although much further mapping and geochronological work is required, granitic magmatism appears to have persisted throughout much of the ~1100 to 900 Ma period that spans the Sveconorwegian orogen. This magmatism is consistently ferroan (i.e. dry); however, the SMB marks a clear transition to magnesian (i.e. wet) magmatism, with a return to ferroan magmatism at >990 Ma. We propose that this transition corresponds to subduction-driven dehydration-melting of the mantle, producing the SMB in a traditional continental volcanic arc environment. A large lower-crustal input is typical of continental arc batholiths (DeCelles et al., 2009). The interpretation of the SMB as a continental arc is key, but not exclusive, to an accretionary model for the Sveconorwegian orogen. The exact timing and setting of syn-/late-Sveconorwegian 990 to 940 Ma ferroan magmatism thus remains a critical link in the understanding of this orogen. Slagstad et al. (in press) A Non-Collisional, Accretionary Sveconorwegian Orogen. Terra Nova, DOI:10.1111/ter.120012 DeCelles et al. (2009) Cyclicity in Cordilleran orogenic systems. Nature Geoscience 2, 251-257.

Does Kinematic Alignment and Flexion of a Femoral Component Designed for Mechanical Alignment Reduce the Proximal and Lateral Reach of the Trochlea?

PubMed

Brar, Abheetinder S; Howell, Stephen M; Hull, Maury L; Mahfouz, Mohamed R

2016-08-01

Kinematically aligned total knee arthroplasty uses a femoral component designed for mechanical alignment (MA) and sets the component in more internal, valgus, and flexion rotation than MA. It is unknown how much kinematic alignment (KA) and flexion of the femoral component reduce the proximal and lateral reach of the trochlea; two reductions that could increase the risk of abnormal patella tracking. We simulated MA and KA of the femoral component in 0° of flexion on 20 3-dimensional bone models of normal femurs. The mechanically and kinematically aligned components were then aligned in 5°, 10°, and 15° of flexion and downsized until the flange contacted the anterior femur. The reductions in the proximal and lateral reach from the proximal point of the trochlea of the MA component set in 0° of flexion were computed. KA at 0° of flexion did not reduce the proximal reach and reduced the lateral reach an average of 3 mm. Flexion of the MA and KA femoral component 5°, 10°, and 15° reduced the proximal reach an average of 4 mm, 8 mm, and 12 mm, respectively (0.8 mm/degree of flexion), and reduced the lateral reach an average of 1 mm and 4 mm regardless of the degree of flexion, respectively. Arthroplasty surgeons and biomechanical engineers striving to optimize patella tracking might consider developing surgical techniques to minimize flexion of the femoral component when performing KA and MA total knee arthroplasty to promote early patella engagement and consider designing a femoral component with a trochlea shaped specifically for KA. Copyright © 2016 Elsevier Inc. All rights reserved.

Intensity, Duration, and Location of High-Definition Transcranial Direct Current Stimulation for Tinnitus Relief.

PubMed

Shekhawat, Giriraj Singh; Sundram, Frederick; Bikson, Marom; Truong, Dennis; De Ridder, Dirk; Stinear, Cathy M; Welch, David; Searchfield, Grant D

2016-05-01

Tinnitus is the perception of a phantom sound. The aim of this study was to compare current intensity (center anode 1 mA and 2 mA), duration (10 minutes and 20 minutes), and location (left temporoparietal area [LTA] and dorsolateral prefrontal cortex [DLPFC]) using 4 × 1 high-definition transcranial direct current stimulation (HD-tDCS) for tinnitus reduction. Twenty-seven participants with chronic tinnitus (>2 years) and mean age of 53.5 years underwent 2 sessions of HD-tDCS of the LTA and DLPFC in a randomized order with a 1 week gap between site of stimulation. During each session, a combination of 4 different settings were used in increasing dose (1 mA, 10 minutes; 1 mA, 20 minutes; 2 mA, 10 minutes; and 2 mA, 20 minutes). The impact of different settings on tinnitus loudness and annoyance was documented. Twenty-one participants (77.78%) reported a minimum of 1 point reduction on tinnitus loudness or annoyance scales. There were significant changes in loudness and annoyance for duration of stimulation,F(1, 26) = 10.08,P< .005, and current intensity,F(1, 26) = 14.24,P= .001. There was no interaction between the location, intensity, and duration of stimulation. Higher intensity (2 mA) and longer duration (20 minutes) of stimulation were more effective. A current intensity of 2 mA for 20-minute duration was the most effective setting used for tinnitus relief. The stimulation of the LTA and DLPFC were equally effective for suppressing tinnitus loudness and annoyance. © The Author(s) 2015.

Spatiotemporal and spectral characteristics of X-ray radiation emitted by the Z-pinch during the current implosion of quasispherical multiwire arrays

NASA Astrophysics Data System (ADS)

Gritsuk, A. N.

2017-12-01

For the first time, a quasi-spherical current implosion has been experimentally realized on a multimegaampere facility with the peak current of up to 4 MA and a soft X-ray source has been created with high radiation power density on its surface of up to 3 TW/cm2. An increase in the energy density at the centre of the source of soft X-ray radiation (SXR) was experimentally observed upon compression of quasi-spherical arrays with the linear-mass profiling. In this case, the average power density on the surface of the SXR source is three times higher than for implosions of cylindrical arrays of the same mass and close values of the discharge current. Obtained experimental data are compared with the results of modelling the current implosion of multi-wire arrays performed with the help of a three-dimensional radiation-magneto-hydrodynamic code.

Gender difference in early initiation of methamphetamine use among current methamphetamine users in Muse, Northern Shan State, Myanmar.

PubMed

Saw, Yu Mon; Saw, Thu Nandar; Yasuoka, Junko; Chan, Nyein; Kham, Nang Pann Ei; Khine, Wint; Cho, Su Myat; Jimba, Masamine

2017-05-08

Globally, methamphetamine (MA) use is a significant public health concern due to unprecedented health effects of its use. However, gender similarities and differences in early age of MA initiation and its risk factors among current MA users have been understudied in a developing country setting. A community-based, cross-sectional study was conducted using a computer assisted self-interviewing program from January to March 2013 in Muse, Northern Shan State, Myanmar. A total of 1362 (775 male and 587 female) self-reported current MA users aged between 18 and 35 years were recruited using respondent-driven sampling. Two gender-stratified multiple logistic regression models (models I and II) were done for analysis. For similarities, 73.0% of males and 60.5% of females initiated MA before their 18th birthday. The early age of MA initiation was positively associated with the reasons and places of the first time MA use among both genders. For differences, males [hazard ratio 1.35; 95% confidence interval, 1.18-1.54] had a significantly higher risk than females to initiate MA at earlier age. Among male users, participants who had bisexual/homosexual preferences were more likely to initiate MA use earlier. In contrast, female users who exchanged sex for money and/or drugs were more likely to initiate MA in earlier age. More than 60.0% of male and female participants initiated MA use early; however, males initiated use earlier than females. Although similarities were found among both genders, differences found in key risk factors for early age MA initiation suggest that gender-specific, MA prevention programs are urgently needed in Myanmar.

Construction and commissioning of the compact energy-recovery linac at KEK

NASA Astrophysics Data System (ADS)

Akemoto, Mitsuo; Arakawa, Dai; Asaoka, Seiji; Cenni, Enrico; Egi, Masato; Enami, Kazuhiro; Endo, Kuninori; Fukuda, Shigeki; Furuya, Takaaki; Haga, Kaiichi; Hajima, Ryoichi; Hara, Kazufumi; Harada, Kentaro; Honda, Tohru; Honda, Yosuke; Honma, Teruya; Hosoyama, Kenji; Kako, Eiji; Katagiri, Hiroaki; Kawata, Hiroshi; Kobayashi, Yukinori; Kojima, Yuuji; Kondou, Yoshinari; Tanaka, Olga; Kume, Tatsuya; Kuriki, Masao; Matsumura, Hiroshi; Matsushita, Hideki; Michizono, Shinichiro; Miura, Takako; Miyajima, Tsukasa; Nagahashi, Shinya; Nagai, Ryoji; Nakai, Hirotaka; Nakajima, Hiromitsu; Nakamura, Norio; Nakanishi, Kota; Nigorikawa, Kazuyuki; Nishimori, Nobuyuki; Nogami, Takashi; Noguchi, Shuichi; Obina, Takashi; Qiu, Feng; Sagehashi, Hidenori; Sakai, Hiroshi; Sakanaka, Shogo; Sasaki, Shinichi; Satoh, Kotaro; Sawamura, Masaru; Shimada, Miho; Shinoe, Kenji; Shishido, Toshio; Tadano, Mikito; Takahashi, Takeshi; Takai, Ryota; Takenaka, Tateru; Tanimoto, Yasunori; Uchiyama, Takashi; Ueda, Akira; Umemori, Kensei; Watanabe, Ken; Yamamoto, Masahiro

2018-01-01

Energy-recovery linacs (ERLs) are promising for advanced synchrotron light sources, high-power free electron lasers (FELs), high-brightness gamma-ray sources, and electron-ion colliders. To demonstrate the critical technology of ERL-based light sources, we have designed and constructed a test accelerator, the compact ERL (cERL). Using advanced technology that includes a photocathode direct current (DC) electron gun and two types of 1.3-GHz-frequency superconducting cavities, the cERL was designed to be capable of recirculating low emittance (≤1 mm ṡ mrad) and high average-current (≥10 mA) electron beams while recovering the beam energy. During initial commissioning, the cERL demonstrated successful recirculation of high-quality beams with normalized transverse emittance of ∼0.14 mm ṡ mrad and momentum spread of ∼1.2 × 10-4 (rms) at a beam energy of 20 MeV and bunch charge below 100 fC. Energy recovery in the superconducting main linac was also demonstrated for high-average-current continuous-wave beams. These results constitute an important milestone toward realizing ERL-based light sources.

Paleosecular variation and time-averaged field analysis over the last 10 Ma from a new global dataset (PSV10)

NASA Astrophysics Data System (ADS)

Cromwell, G.; Johnson, C. L.; Tauxe, L.; Constable, C.; Jarboe, N.

2015-12-01

Previous paleosecular variation (PSV) and time-averaged field (TAF) models draw on compilations of paleodirectional data that lack equatorial and high latitude sites and use latitudinal virtual geomagnetic pole (VGP) cutoffs designed to remove transitional field directions. We present a new selected global dataset (PSV10) of paleodirectional data spanning the last 10 Ma. We include all results calculated with modern laboratory methods, regardless of site VGP colatitude, that meet statistically derived selection criteria. We exclude studies that target transitional field states or identify significant tectonic effects, and correct for any bias from serial correlation by averaging directions from sequential lava flows. PSV10 has an improved global distribution compared with previous compilations, comprising 1519 sites from 71 studies. VGP dispersion in PSV10 varies with latitude, exhibiting substantially higher values in the southern hemisphere than at corresponding northern latitudes. Inclination anomaly estimates at many latitudes are within error of an expected GAD field, but significant negative anomalies are found at equatorial and mid-northern latitudes. Current PSV models Model G and TK03 do not fit observed PSV or TAF latitudinal behavior in PSV10, or subsets of normal and reverse polarity data, particularly for southern hemisphere sites. Attempts to fit these observations with simple modifications to TK03 showed slight statistical improvements, but still exceed acceptable errors. The root-mean-square misfit of TK03 (and subsequent iterations) is substantially lower for the normal polarity subset of PSV10, compared to reverse polarity data. Two-thirds of data in PSV10 are normal polarity, most which are from the last 5 Ma, so we develop a new TAF model using this subset of data. We use the resulting TAF model to explore whether new statistical PSV models can better describe our new global compilation.

The relative ease of obtaining a dermatologic appointment in Boston: how methods drive results.

PubMed

Weingold, David Howard; Lack, Michael Dweight; Yanowitz, Karen Leslie

2009-06-01

Recent reports have indicated long wait times for dermatologic appointments even for changing moles. Our objective was to determine the wait time for a person willing to make multiple calls and accept an appointment from any dermatologist at any satellite location for a changing mole from a dermatologist who advertised in a Boston, MA, telephone book. We telephoned each practice listed in a Boston, MA, telephone book. Patients making one call to each dermatologic practice on average obtained an appointment in 18 days. Patients calling two practices were offered an appointment on average in 7 days. Patients calling 3 practices were also offered an appointment in 1 week. We only telephoned practices listed in a Boston, MA, telephone book and we only surveyed one urban area. These results suggest that a reasonable concerned patient who was willing to make multiple calls to different providers in Boston, MA, can be seen in a timely fashion.

Performance of the LANSCE H^- Source and Low Energy Transport at Higher Peak Current

NASA Astrophysics Data System (ADS)

Pillai, Chandra; Stevens, Ralph; Fitzgerald, Daniel; Garnett, Robert; Ingllas, William; Merrill, Frank; Rybarcyk, Larry; Sander, Oscar

1997-05-01

The Los Alamos Neutron Science Center (LANSCE) 800 MeV linac facility uses a multicusp field, surface ion source to produce H^- beam for delivery to the Proton Storage Ring (PSR) and to the Weapon Neutron Research (WNR) areas. The source typically operates at a duty factor of 9.4% delivering a peak current of about 14 mA into the 750 keV LEBT. Each beam macropulse is chopped to create a sequence of 360 ns pulse, each with a 100 ns ``extraction notch'' for injection into PSR. The average current delivered to the short-pulse spallation target is nominally 70μA. One goal of the present PSR upgrade projects is an increase in the average beam current to 200μA. This will be accomplished by a combination of increased repetition rate (to 30 Hz), upgraded PSR bunchers, and a brighter H^- ion source that will produce higher peak current with lower beam emittance. The present ion source and injector system was studied to investigate the beam qualities of the source and the performance of the low energy transpot. The performance of the ion source at higher currents and the change in beam parameters in the low energy transport compared to those in the standard source conditions will be presented.

Scaling of X pinches from 1 MA to 6 MA.

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

Bland, Simon Nicholas; McBride, Ryan D.; Wenger, David Franklin

This final report for Project 117863 summarizes progress made toward understanding how X-pinch load designs scale to high currents. The X-pinch load geometry was conceived in 1982 as a method to study the formation and properties of bright x-ray spots in z-pinch plasmas. X-pinch plasmas driven by 0.2 MA currents were found to have source sizes of 1 micron, temperatures >1 keV, lifetimes of 10-100 ps, and densities >0.1 times solid density. These conditions are believed to result from the direct magnetic compression of matter. Physical models that capture the behavior of 0.2 MA X pinches predict more extreme parametersmore » at currents >1 MA. This project developed load designs for up to 6 MA on the SATURN facility and attempted to measure the resulting plasma parameters. Source sizes of 5-8 microns were observed in some cases along with evidence for high temperatures (several keV) and short time durations (<500 ps).« less

Medicare Advantage Members' Expected Out-Of-Pocket Spending For Inpatient And Skilled Nursing Facility Services.

PubMed

Keohane, Laura M; Grebla, Regina C; Mor, Vincent; Trivedi, Amal N

2015-06-01

Inpatient and skilled nursing facility (SNF) cost sharing in Medicare Advantage (MA) plans may reduce unnecessary use of these services. However, large out-of-pocket expenses potentially limit access to care and encourage beneficiaries at high risk of needing inpatient and postacute care to avoid or leave MA plans. In 2011 new federal regulations restricted inpatient and skilled nursing facility cost sharing and mandated limits on out-of-pocket spending in MA plans. After these regulations, MA members in plans with low premiums averaged $1,758 in expected out-of-pocket spending for an episode of seven hospital days and twenty skilled nursing facility days. Among members with the same low-premium plan in 2010 and 2011, 36 percent of members belonged to plans that added an out-of-pocket spending limit in 2011. However, these members also had a $293 increase in average cost sharing for an inpatient and skilled nursing facility episode, possibly to offset plans' expenses in financing out-of-pocket limits. Some MA beneficiaries may still have difficulty affording acute and postacute care despite greater regulation of cost sharing. Project HOPE—The People-to-People Health Foundation, Inc.

Medicare Advantage Members’ Expected Out-Of-Pocket Spending For Inpatient And Skilled Nursing Facility Services

PubMed Central

Keohane, Laura M.; Grebla, Regina C.; Mor, Vincent; Trivedi, Amal N.

2015-01-01

Inpatient and skilled nursing facility (SNF) cost sharing in Medicare Advantage (MA) plans may reduce unnecessary use of these services. However, large out-of-pocket expenses potentially limit access to care and encourage beneficiaries at high risk of needing inpatient and postacute care to avoid or leave MA plans. In 2011 new federal regulations restricted inpatient and skilled nursing facility cost sharing and mandated limits on out-of-pocket spending in MA plans. After these regulations, MA members in plans with low premiums averaged $1,758 in expected out-of-pocket spending for an episode of seven hospital days and twenty skilled nursing facility days. Among members with the same low-premium plan in 2010 and 2011, 36 percent of members belonged to plans that added an out-of-pocket spending limit in 2011. However, these members also had a $293 increase in average cost sharing for an inpatient and skilled nursing facility episode, possibly to offset plans’ expenses in financing out-of-pocket limits. Some MA beneficiaries may still have difficulty affording acute and postacute care despite greater regulation of cost sharing. PMID:26056208

Pyrite (FeS2) nanocrystals as inexpensive high-performance lithium-ion cathode and sodium-ion anode materials

NASA Astrophysics Data System (ADS)

Walter, Marc; Zünd, Tanja; Kovalenko, Maksym V.

2015-05-01

In light of the impeding depletion of fossil fuels and necessity to lower carbon dioxide emissions, economically viable high-performance batteries are urgently needed for numerous applications ranging from electric cars to stationary large-scale electricity storage. Due to its low raw material cost, non-toxicity and potentially high charge-storage capacity pyrite (FeS2) is a highly promising material for such next-generation batteries. In this work we present the electrochemical performance of FeS2 nanocrystals (NCs) as lithium-ion and sodium-ion storage materials. First, we show that nanoscopic FeS2 is a promising lithium-ion cathode material, delivering a capacity of 715 mA h g-1 and average energy density of 1237 Wh kg-1 for 100 cycles, twice higher than for commonly used LiCoO2 cathodes. Then we demonstrate, for the first time, that FeS2 NCs can serve as highly reversible sodium-ion anode material with long cycling life. As sodium-ion anode material, FeS2 NCs provide capacities above 500 mA h g-1 for 400 cycles at a current rate of 1000 mA g-1. In all our tests and control experiments, the performance of chemically synthesized nanoscale FeS2 clearly surpasses bulk FeS2 as well as large number of other nanostructured metal sulfides.In light of the impeding depletion of fossil fuels and necessity to lower carbon dioxide emissions, economically viable high-performance batteries are urgently needed for numerous applications ranging from electric cars to stationary large-scale electricity storage. Due to its low raw material cost, non-toxicity and potentially high charge-storage capacity pyrite (FeS2) is a highly promising material for such next-generation batteries. In this work we present the electrochemical performance of FeS2 nanocrystals (NCs) as lithium-ion and sodium-ion storage materials. First, we show that nanoscopic FeS2 is a promising lithium-ion cathode material, delivering a capacity of 715 mA h g-1 and average energy density of 1237 Wh kg-1 for 100 cycles, twice higher than for commonly used LiCoO2 cathodes. Then we demonstrate, for the first time, that FeS2 NCs can serve as highly reversible sodium-ion anode material with long cycling life. As sodium-ion anode material, FeS2 NCs provide capacities above 500 mA h g-1 for 400 cycles at a current rate of 1000 mA g-1. In all our tests and control experiments, the performance of chemically synthesized nanoscale FeS2 clearly surpasses bulk FeS2 as well as large number of other nanostructured metal sulfides. Electronic supplementary information (ESI) available: Materials and methods, additional structural and electrochemical characterization. See DOI: 10.1039/c5nr00398a

Middle atmosphere electrical energy coupling

NASA Technical Reports Server (NTRS)

Hale, L. C.

1989-01-01

The middle atmosphere (MA) has long been known as an absorber of radio waves, and as a region of nonlinear interactions among waves. The region of highest transverse conductivity near the top of the MA provides a common return for global thunderstorm, auroral Birkeland, and ionospheric dynamo currents, with possibilities for coupling among them. Their associated fields and other transverse fields map to lower altitudes depending on scale size. Evidence now exists for motion-driven aerosol generators, and for charge trapped at the base of magnetic field lines, both capable of producing large MA electric fields. Ionospheric Maxwell currents (curl H) parallel to the magnetic field appear to map to lower altitudes, with rapidly time-varying components appearing as displacement currents in the stratosphere. Lightning couples a (primarily ELF and ULF) current transient to the ionosphere and magnetosphere whose wave shape is largely dependent on the MA conductivity profile. Electrical energy is of direct significance mainly in the upper MA, but electrodynamic transport of minor constituents such as smoke particles or CN may be important at other altitudes.

Impact of reduced-radiation dual-energy protocols using 320-detector row computed tomography for analyzing urinary calculus components: initial in vitro evaluation.

PubMed

Cai, Xiangran; Zhou, Qingchun; Yu, Juan; Xian, Zhaohui; Feng, Youzhen; Yang, Wencai; Mo, Xukai

2014-10-01

To evaluate the impact of reduced-radiation dual-energy (DE) protocols using 320-detector row computed tomography on the differentiation of urinary calculus components. A total of 58 urinary calculi were placed into the same phantom and underwent DE scanning with 320-detector row computed tomography. Each calculus was scanned 4 times with the DE protocols using 135 kV and 80 kV tube voltage and different tube current combinations, including 100 mA and 570 mA (group A), 50 mA and 290 mA (group B), 30 mA and 170 mA (group C), and 10 mA and 60 mA (group D). The acquisition data of all 4 groups were then analyzed by stone DE analysis software, and the results were compared with x-ray diffraction analysis. Noise, contrast-to-noise ratio, and radiation dose were compared. Calculi were correctly identified in 56 of 58 stones (96.6%) using group A and B protocols. However, only 35 stones (60.3%) and 16 stones (27.6%) were correctly diagnosed using group C and D protocols, respectively. Mean noise increased significantly and mean contrast-to-noise ratio decreased significantly from groups A to D (P <.05). In addition, the effective dose decreased markedly from groups A to D at 3.78, 1.81, 1.07, and 0.37 mSv, respectively. Decreasing the DE tube currents from 100 mA and 570 mA to 50 mA and 290 mA resulted in 96.6% accuracy for urinary calculus component analysis while reducing patient radiation exposure to 1.81 mSv. Further reduction of tube currents may compromise diagnostic accuracy. Copyright © 2014 Elsevier Inc. All rights reserved.

Impact and mitigation of disruptions with the ITER-like wall in JET

NASA Astrophysics Data System (ADS)

Lehnen, M.; Arnoux, G.; Brezinsek, S.; Flanagan, J.; Gerasimov, S. N.; Hartmann, N.; Hender, T. C.; Huber, A.; Jachmich, S.; Kiptily, V.; Kruezi, U.; Matthews, G. F.; Morris, J.; Plyusnin, V. V.; Reux, C.; Riccardo, V.; Sieglin, B.; de Vries, P. C.; EFDA Contributors, JET

2013-09-01

Disruptions are a critical issue for ITER because of the high thermal and magnetic energies that are released on short timescales, which results in extreme forces and heat loads. The choice of material of the plasma-facing components (PFCs) can have significant impact on the loads that arise during a disruption. With the ITER-like wall (ILW) in JET made of beryllium in the main chamber and tungsten in the divertor, the main finding is a low fraction of radiation. This has dropped significantly with the ILW from 50-100% of the total energy being dissipated during disruptions in CFC wall plasmas, to less than 50% on average and down to just 10% for vertical displacement events (VDEs). All other changes in disruption properties and loads are consequences of this low radiation: long current quenches (CQs), high vessel forces caused by halo currents and toroidal current asymmetries as well as severe heat loads. Temperatures close to the melting limit have been locally observed on upper first wall structures during deliberate VDE and even at plasma currents as low as 1.5 MA and thermal energy of about 1.5 MJ only. A high radiation fraction can be regained by massive injection of a mixture of 10% Ar with 90% D2. This accelerates the CQ thus reducing the halo current and sideways impulse. The temperature of PFCs stays below 400 °C. MGI is now a mandatory tool to mitigate disruptions in closed-loop operation for currents at and above 2.5 MA in JET.

Using cosmogenic nuclides to contrast rates of erosion and sediment yield in a semi-arid, arroyo-dominated landscape, Rio Puerco Basin, New Mexico

USGS Publications Warehouse

Bierman, P.R.; Reuter, J.M.; Pavich, M.; Gellis, A.C.; Caffee, M.W.; Larsen, J.

2005-01-01

Analysis of in-situ-produced 10Be and 26Al in 52 fluvial sediment samples shows that millennial-scale rates of erosion vary widely (7 to 366 m Ma-1) through the lithologically and topographically complex Rio Puerco Basin of northern New Mexico. Using isotopic analysis of both headwater and downstream samples, we determined that the semi-arid, Rio Puerco Basin is eroding, on average, about 100 m Ma-1. This rapid rate of erosion is consistent with estimates made using other techniques and is likely to result from a combination of easily eroded lithologies, sparse vegetation, and monsoon-dominated rainfall. Data from 331 stream water samples collected by the US Geological Survey between 1960 and 1995 are consistent with basin-wide, average chemical denudation rates of only about 1??4 m Ma-1; thus, the erosion rates we calculate may be considered rates of sediment generation because physical weathering accounts for almost 99 per cent of mass loss. The isotopic data reveal that sediment is generally well mixed downstream with the area-weighted average sediment generation rate for 16 headwater samples (234 ton km-2 a-1 for basin area 170 to 1169 km2) matching well that estimated from a single sample collected far downstream (238 ton km-2 a-1, basin area = 14 225 km2). A series of 15 samples, collected from an arroyo wall and representing deposition through the late Holocene, indicates that 10Be concentration in sediment delivered by the fluvial system has not changed appreciably over the last 1200 years despite at least two cycles of arroyo cutting and filling. Other samples (n = 21) were collected along the drainage network. Rio Puerco erosion rates scale directly with a variety of metrics describing vegetation, precipitation, and rock erodibility. Using the headwater basins for calibration, the erosion rates for both the downstream samples and also the data set as a whole, are best modelled by considering a combination of relief and vegetation metrics, both of which co-vary with precipitation and erodibility as inferred from lithology. On average, contemporary sediment yields, determined by monitoring suspended-sediment discharge, exceed cosmogenically determined millennial-scale erosion rates by nearly a factor of two. This discrepancy, between short-term rates of sediment yield and long-term rates of erosion, suggests that more sediment is currently being exported from the basin than is being produced. Because the failure of incised channel walls and the head cutting of arroyo complexes appear to be the main sources of channel sediment today, this incongruence between rates of sediment supply and sediment yield is likely to be transitory, reflecting the current states of the arroyo cycle and perhaps the influence of current or past land-use patterns. Copyright ?? 2005 John Wiley & Sons, Ltd.

Earth's partial pressure of CO2 over the past 100-500 Ma; evidence from Ce anomalies in mostly shallow seas (less than 200 m) as recorded in carbonate sediments, 2

NASA Technical Reports Server (NTRS)

Liu, Y.-G.; Reinhardt, J. W.; Schmitt, R. A.

1993-01-01

We reported the direct relationship of Ce anomalies recorded in 0.2-119 Ma CaCO3 sediments (Ce(sup A*)) to the Ce anomalies in the parental Pacific deep seawater (Ce(sup A)) and their relationship to atmospheric P(CO2) relative to present P(CO2). We have analyzed continental CaCO3 samples that were deposited in ancient oceans and shallow sea platforms less than 200 m over central USA, central Europe, China, and Saudi-Arabia/Oman. We have plotted Ce(sup A*) over the 75-470 Ma interval. For P(CO2) calculations, we assumed as a reference standard the less than 200 m mixed Pacific Ocean with a Ce(sup A) geometric mean of 0.22 and a range of 0.10-0.43. Because P(CO2) values obtained from reliable deep Pacific Ocean carbonates in the 67-119 Ma interval were similar to the present P(CO2) values, we have drawn a 1.0 ratio for that interval. Although there is considerable scatter among the approximately 150 Ma carbonates, the average Ce(sup A*) value suggests that P(CO2) increased during the early Cretaceous, from 1.0X at approximately 120 Ma to about 1.4X at approximately 150 Ma. At approximately 250 Ma, the average Ce(sup A*) in 13 shallow sea China carbonates agrees well with the single and more reliable approximately 250 Ma China carbonate deposited in deeper open platform. We suggest that P(CO2) ranged from 1.4-1.7X over the Jurassic and Triassic periods. At approximately 280 Ma, three China carbonates deposited in deeper open platforms and therefore considered more reliable are consistent with a European carbonate, which indicate Ce(sup A) and P(CO2) values similar to the present. The minimum at this time corresponds to the great Permo-Carboniferous glaciation. From 280 Ma to 470 Ma, the trend favors increasing Ce(sup A*) and corresponding P(CO2) values between 1.9-2.7X, with a more reliable value closer to 2.7X at 430 Ma because of the unknown higher temperature in the less than 100 m seawater over continental USA which was located just south of the equator at approximately 430 Ma.

Electrode effects on temporal changes in electrolyte pH and redox potential for water treatment

PubMed Central

Ciblak, Ali; Mao, Xuhui; Padilla, Ingrid; Vesper, Dorothy; Alshawabkeh, Iyad; Alshawabkeh, Akram N.

2012-01-01

The performance of electrochemical remediation methods could be optimized by controlling the physicochemical conditions of the electrochemical redox system. The effects of anode type (reactive or inert), current density and electrolyte composition on the temporal changes in pH and redox potential of the electrolyte were evaluated in divided and mixed electrolytes. Two types of electrodes were used: iron as a reactive electrode and mixed metal oxide coated titanium (MMO) as an inert electrode. Electric currents of 15, 30, 45 and 60 mA (37.5 mA L−1, 75 mA L−1, 112.5 mA L−1 and 150 mA L−1) were applied. Solutions of NaCl, Na2SO4 and NaHCO3 were selected to mimic different wastewater or groundwater composition. Iron anodes resulted in highly reducing electrolyte conditions compared to inert anodes. Electrolyte pH was dependent on electrode type, electrolyte composition and current density. The pH of mixed-electrolyte was stable when MMO electrodes were used. When iron electrodes were used, the pH of electrolyte with relatively low current density (37.5 mA L−1) did not show significant changes but the pH increased sharply for relatively high current density (150 mA L−1). Sulfate solution showed more basic and relatively more reducing electrolyte condition compared to bicarbonate and chloride solution. The study shows that a highly reducing environment could be achieved using iron anodes in divided or mixed electrolytes and the pH and redox potential could be optimized by using appropriate current and polarity reversal. PMID:22416866

Development of compact rapid charging power supply for capacitive energy storage in pulsed power drivers.

PubMed

Sharma, Surender Kumar; Shyam, Anurag

2015-02-01

High energy capacitor bank is used for primary electrical energy storage in pulsed power drivers. The capacitors used in these pulsed power drivers have low inductance, low internal resistance, and less dc life, so it has to be charged rapidly and immediately discharged into the load. A series resonant converter based 45 kV compact power supply is designed and developed for rapid charging of the capacitor bank with constant charging current up to 150 mA. It is short circuit proof, and zero current switching technique is used to commute the semiconductor switch. A high frequency resonant inverter switching at 10 kHz makes the overall size small and reduces the switching losses. The output current of the power supply is limited by constant on-time and variable frequency switching control technique. The power supply is tested by charging the 45 kV/1.67 μF and 15 kV/356 μF capacitor banks. It has charged the capacitor bank up to rated voltage with maximum charging current of 150 mA and the average charging rate of 3.4 kJ/s. The output current of the power supply is limited by reducing the switching frequency at 5 kHz, 3.3 kHz, and 1.7 kHz and tested with 45 kV/1.67 μF capacitor bank. The protection circuit is included in the power supply for over current, under voltage, and over temperature. The design details and the experimental testing results of the power supply for resonant current, output current, and voltage traces of the power supply with capacitive, resistive, and short circuited load are presented and discussed.

U-Th-Pb zircon ages of some Keweenawan Supergroup rocks from the south shore of Lake Superior

USGS Publications Warehouse

Zartman, R.E.; Nicholson, S.W.; Cannon, W.F.; Morey, G.B.

1997-01-01

New single-crystal zircon U-Th-Pb ages for plutonic and rhyolitic Keweenawan Supergroup rocks from the south shore of Lake Superior provide geochronological constraints on magmatic evolution associated with the 1.1 Ga Midcontinent rift. Analyses of a granophyric phase of the Mineral Lake intrusion and the Meilen granite, both parts of the Meilen Intrusive Complex, and a laterally extensive rhyolite from the top of the Kallander Creek Volcanics have weighted average 207Pb/206Pb ages of 1102.0 ?? 2.8 Ma (N = 2), 1100.9 ?? 1.4 Ma (N = 5), and 1098.8 ?? 1.9 Ma (N = 4), respectively. Analyses of a pyroclastic rhyolite flow at the top of the Porcupine Volcanics result in variable 207Pb/206Pb ages that range from 1080 to 1137 Ma. This rhyolite exhibits a continuum between morphologically complex and simpler prismatic zircon crystals, the latter yielding concordant analyses having a weighted average 207Pb/206Pb age of 1093.6 ?? 1.8 Ma (N = 2). Four prismatic zircons from an aphyric rhyolite of the Chengwatana Volcanics in the Ashland syncline form a linear array intersecting concordia at 1094.6 ?? 2.1 Ma (MSWD = 1.3). Another presumed Chengwatana rhyolite recovered from drill core intersecting the Hudson-Afton horst in southeast Minnesota yielded only ???20 morphologically indistinguishable zircons. Six analyses give 207Pb/206Pb ages ranging from 1112 to 1136 Ma, including one analysis with a virtually concordant age of 1130 Ma. This age, however, is considerably older than that obtained for the Chengwatana Volcanics in the Ashland syncline or any other precisely dated rock from the Midcontinent rift.

The rigid-plate and shrinking-plate hypotheses: Implications for the azimuths of transform faults

NASA Astrophysics Data System (ADS)

Mishra, Jay Kumar; Gordon, Richard G.

2016-08-01

The rigid-plate hypothesis implies that oceanic lithosphere does not contract horizontally as it cools (hereinafter "rigid plate"). An alternative hypothesis, that vertically averaged tensional thermal stress in the competent lithosphere is fully relieved by horizontal thermal contraction (hereinafter "shrinking plate"), predicts subtly different azimuths for transform faults. The size of the predicted difference is as large as 2.44° with a mean and median of 0.46° and 0.31°, respectively, and changes sign between right-lateral (RL)-slipping and left-lateral (LL)-slipping faults. For the MORVEL transform-fault data set, all six plate pairs with both RL- and LL-slipping faults differ in the predicted sense, with the observed difference averaging 1.4° ± 0.9° (95% confidence limits), which is consistent with the predicted difference of 0.9°. The sum-squared normalized misfit, r, to global transform-fault azimuths is minimized for γ = 0.8 ± 0.4 (95% confidence limits), where γ is the fractional multiple of the predicted difference in azimuth between the shrinking-plate (γ = 1) and rigid-plate (γ = 0) hypotheses. Thus, observed transform azimuths differ significantly between RL-slipping and LL-slipping faults, which is inconsistent with the rigid-plate hypothesis but consistent with the shrinking-plate hypothesis, which indicates horizontal shrinking rates of 2% Ma-1 for newly created lithosphere, 1% Ma-1 for 0.1 Ma old lithosphere, 0.2% Ma-1 for 1 Ma old lithosphere, and 0.02% Ma-1 for 10 Ma old lithosphere, which are orders of magnitude higher than the mean intraplate seismic strain rate of 10-6 Ma-1 (5 × 10-19 s-1).

Static resistivity image of a cubic saline phantom in magnetic resonance electrical impedance tomography (MREIT).

PubMed

Lee, Byung Il; Oh, Suk Hoon; Woo, Eung Je; Lee, Soo Yeol; Cho, Min Hyeong; Kwon, Ohin; Seo, Jin Keun; Baek, Woon Sik

2003-05-01

In magnetic resonance electrical impedance tomography (MREIT) we inject currents through electrodes placed on the surface of a subject and try to reconstruct cross-sectional resistivity (or conductivity) images using internal magnetic flux density as well as boundary voltage measurements. In this paper we present a static resistivity image of a cubic saline phantom (50 x 50 x 50 mm3) containing a cylindrical sausage object with an average resistivity value of 123.7 ohms cm. Our current MREIT system is based on an experimental 0.3 T MRI scanner and a current injection apparatus. We captured MR phase images of the phantom while injecting currents of 28 mA through two pairs of surface electrodes. We computed current density images from magnetic flux density images that are proportional to the MR phase images. From the current density images and boundary voltage data we reconstructed a cross-sectional resistivity image within a central region of 38.5 x 38.5 mm2 at the middle of the phantom using the J-substitution algorithm. The spatial resolution of the reconstructed image was 64 x 64 and the reconstructed average resistivity of the sausage was 117.7 ohms cm. Even though the error in the reconstructed average resistivity value was small, the relative L2-error of the reconstructed image was 25.5% due to the noise in measured MR phase images. We expect improvements in the accuracy by utilizing an MRI scanner with higher SNR and increasing the size of voxels scarifying the spatial resolution.

Effect of cathodic current density on performance of tungsten coatings on molybdenum prepared by electrodeposition in molten salt

NASA Astrophysics Data System (ADS)

Jiang, Fan

2016-02-01

Smooth tungsten coatings were prepared at current density below 70 mA cm-2 by electrodeposition on molybdenum substrate from Na2WO4-WO3 -melt at 1173 K in air atmosphere. As the current density reached up to 90 mA cm-2, many significant nodules were observed on the surface of the coating. Surface characterization, microstructure and mechanical properties were performed on the tungsten coatings. As the increasing of current density, the preferred orientation of the coatings changed to (2 0 0). All coatings exhibited columnar-grained-crystalline. There was about a 2 μm thick diffusion layer between tungsten coating and molybdenum substrate. The bending test revealed the tungsten coating had -good bonding strength with the molybdenum substrate. There is a down trend of the grain size of the coating on molybdenum as the current density increased from 30 mA cm-2 to 50 mA cm-2. The coating obtained at 50 mA cm-2 had a minimum grain size of 4.57 μm, while the microhardness of this coating reached to a maximum value of 495 HV.

JPSS-1 VIIRS version 2 at-launch relative spectral response characterization and performance

NASA Astrophysics Data System (ADS)

Moeller, Chris; Schwarting, Tom; McIntire, Jeff; Moyer, David I.; Zeng, Jinan

2016-09-01

The relative spectral response (RSR) characterization of the JPSS-1 VIIRS spectral bands has achieved "at launch" status in the VIIRS Data Analysis Working Group February 2016 Version 2 RSR release. The Version 2 release improves upon the June 2015 Version 1 release by including December 2014 NIST TSIRCUS spectral measurements of VIIRS VisNIR bands in the analysis plus correcting CO2 influence on the band M13 RSR. The T-SIRCUS based characterization is merged with the summer 2014 SpMA based characterization of VisNIR bands (Version 1 release) to yield a "fused" RSR for these bands, combining the strengths of the T-SIRCUS and the SpMA measurement systems. The M13 RSR is updated by applying a model-based correction to mitigate CO2 attenuation of the SpMA source signal that occurred during M13 spectral measurements. The Version 2 release carries forward the Version 1 RSR for those bands that were not updated (M8-M12, M14-M16A/B, I3-I5, DNBMGS). The Version 2 release includes band average (over all detectors and subsamples) RSR plus supporting RSR for each detector and subsample. The at-launch band average RSR have been used to populate Look-Up Tables supporting the sensor data record and environmental data record at-launch science products. Spectral performance metrics show that JPSS-1 VIIRS RSR are compliant on specifications with a few minor exceptions. The Version 2 release, which replaces the Version 1 release, is currently available on the password-protected NASA JPSS-1 eRooms under EAR99 control.

Multiple episodes of mineralization revealed by Re-Os molybdenite geochronology in the Lala Fe-Cu deposit, SW China

NASA Astrophysics Data System (ADS)

Zhu, Zhimin; Tan, Hongqi; Liu, Yingdong; Li, Chao

2018-03-01

The Lala Fe-Cu deposit is one of the largest iron oxide-copper-gold (IOCG) deposits in the Kangdian copper belt, southwest China. The paragenetic sequence of the Lala deposit includes six hydrothermal stages: pre-ore pervasive Na alteration (I); magnetite stage with K-feldspar and apatite (II); polymetallic disseminated/massive magnetite-sulfide stage (III); banded magnetite-sulfide stage (IV); sulfide vein stage (V); and late quartz-carbonate vein stage (VI). Fifteen molybdenite separates from stages III to VI were analyzed for Re-Os dating. Our new Re-Os data, together with previous studies, identify four distinct hydrothermal events at the Lala deposit. Molybdenite from the stage III disseminated to massive chalcopyrite-magnetite ores yielded a weighted average Re-Os age of 1306 ± 8 Ma (MSWD = 1.1, n = 6) which represents the timing of main ore formation. Molybdenite from the stage IV-banded magnetite-chalcopyrite ores yielded a weighted average Re-Os age of 1086 ± 8 Ma (MSWD = 2.2, n = 7), i.e., a second ore-forming event. Molybdenite from the stage V sulfide veins yielded a weighted average Re-Os age of 988 ± 8 Ma (MSWD = 1.3, n = 7) which represents the timing of a third hydrothermal event. Molybdenite from the quartz-carbonate veins (stage VI) yielded a weighted average Re-Os age at 835 ± 4 Ma (MSWD = 0.66, n = 10) and documented the timing of a late hydrothermal event. Our results indicate that the Lala deposit formed during multiple, protracted mineralization events over several hundred million years. The first three Mesoproterozoic mineralization events are coeval with intra-continental rifting (breakup of the supercontinent Nuna) and share a temporal link to other IOCG-style deposits within the Kangdian Copper Belt, and the last Neoproterozoic hydrothermal event is coeval with the Sibao orogeny which culminated with the amalgamation of the Yangtze Block with the Cathaysia Block at 860-815 Ma.

Liquid-metal-ion source development for space propulsion at ARC.

PubMed

Tajmar, M; Scharlemann, C; Genovese, A; Buldrini, N; Steiger, W; Vasiljevich, I

2009-04-01

The Austrian Research Centers have a long history of developing indium Liquid-Metal-Ion Source (LMIS) for space applications including spacecraft charging compensators, SIMS and propulsion. Specifically the application as a thruster requires long-term operation as well as high-current operation which is very challenging. Recently, we demonstrated the operation of a cluster of single LMIS at an average current of 100muA each for more than 4800h and developed models for tip erosion and droplet deposition suggesting that such a LMIS can operate up to 20,000h or more. In order to drastically increase the current, a porous multi-tip source that allows operation up to several mA was developed. Our paper will highlight the problem areas and challenges from our LMIS development focusing on space propulsion applications.

Reinforcing the North Atlantic backbone: revision and extension of the composite splice at ODP Site 982

NASA Astrophysics Data System (ADS)

Drury, Anna Joy; Westerhold, Thomas; Hodell, David; Röhl, Ursula

2018-03-01

Ocean Drilling Program (ODP) Site 982 represents a key location for understanding the evolution of climate in the North Atlantic over the past 12 Ma. However, concerns exist about the validity and robustness of the underlying stratigraphy and astrochronology, which currently limits the adequacy of this site for high-resolution climate studies. To resolve this uncertainty, we verify and extend the early Pliocene to late Miocene shipboard composite splice at Site 982 using high-resolution XRF core scanning data and establish a robust high-resolution benthic foraminiferal stable isotope stratigraphy and astrochronology between 8.0 and 4.5 Ma. Splice revisions and verifications resulted in ˜ 11 m of gaps in the original Site 982 isotope stratigraphy, which were filled with 263 new isotope analyses. This new stratigraphy reveals previously unseen benthic δ18O excursions, particularly prior to 6.65 Ma. The benthic δ18O record displays distinct, asymmetric cycles between 7.7 and 6.65 Ma, confirming that high-latitude climate is a prevalent forcing during this interval. An intensification of the 41 kyr beat in both the benthic δ13C and δ18O is also observed ˜ 6.4 Ma, marking a strengthening in the cryosphere-carbon cycle coupling. A large ˜ 0.7 ‰ double excursion is revealed ˜ 6.4-6.3 Ma, which also marks the onset of an interval of average higher δ18O and large precession and obliquity-dominated δ18O excursions between 6.4 and 5.4 Ma, coincident with the culmination of the late Miocene cooling. The two largest benthic δ18O excursions ˜ 6.4-6.3 Ma and TG20/22 coincide with the coolest alkenone-derived sea surface temperature (SST) estimates from Site 982, suggesting a strong connection between the late Miocene global cooling, and deep-sea cooling and dynamic ice sheet expansion. The splice revisions and revised astrochronology resolve key stratigraphic issues that have hampered correlation between Site 982, the equatorial Atlantic and the Mediterranean. Comparisons of the revised Site 982 stratigraphy to high-resolution astronomically tuned benthic δ18O stratigraphies from ODP Site 926 (equatorial Atlantic) and Ain el Beida (north-western Morocco) show that prior inconsistencies in short-term excursions are now resolved. The identification of key new cycles at Site 982 further highlights the requirement for the current scheme for late Miocene marine isotope stages to be redefined. Our new integrated deep-sea benthic stable isotope stratigraphy and astrochronology from Site 982 will facilitate future high-resolution late Miocene to early Pliocene climate research.

Palaeomagnetism of the Upper Miocene- Lower Pliocene lavas from the East Carpathians: contribution to the paleosecular variation of geomagnetic field

PubMed Central

Vişan, Mădălina; Panaiotu, Cristian G.; Necula, Cristian; Dumitru, Anca

2016-01-01

Investigations of the paleosecular variation of the geomagnetic field on geological timescales depend on globally distributed data sets from lava flows. We report new paleomagnetic results from lava flows of the East Carpathian Mountains (23.6°E, 46.4°N) erupted between 4 and 6 Ma. The average virtual geomagnetic pole position (76 sites) includes the North Geographic Pole and the dispersion of virtual geomagnetic poles is in general agreement with the data of the Time Averaged geomagnetic Field Initiative. Based on this study and previous results from the East Carpathians obtained from 0.04–4 Ma old lava flows, we show that high value of dispersion are characteristic only for 1.5–2.8 Ma old lava flows. High values of dispersion during the Matuyama chron are also reported around 50°N, in the global paleosecular variation data set. More data are needed at a global level to determine if these high dispersions reflect the behaviour of the geomagnetic field or an artefact of inadequate number of sites. This study of the East Carpathians volcanic rocks brings new data from southeastern Europe and which can contribute to the databases for time averaged field and paleosecular variation from lavas in the last 6 Ma. PMID:26997549

Permian single crystal U-Pb zircon age of the Rožňava Formation volcanites (Southern Gemeric Unit, Western Carpathians, Slovakia)

NASA Astrophysics Data System (ADS)

Vozárová, Anna; Šmelko, Miloš; Paderin, Ilya

2009-12-01

Zircon populations from the Rožňava Formation volcanic rock complex have been analysed. Euhedral zircons from the 1st volcanogenic horizon with fine oscillatory growth zoning, typical of magmatic origin, gave the average concordia age of 273.3 ± 2.8 Ma, with Th/U ratios in the range of 0.44-0.73. The Permian ages ranging from 266 to 284 Ma were identified in the wider, zoned or unzoned, central zircon parts, as well as in their fine-zoned oscillatory rims. The average concordia age of 275.3 ± 2.9 was obtained from the euhedral zircon population of the 2nd volcanogenic horizon of the Rožňava Formation. The analyses were performed on zoned magmatic zircons in the age interval from 267 to 287 Ma, with Th/U ratios in the range of 0.39-0.75. In the later zircon population two inherited zircon grains were dated giving the age of 842 ± 12 Ma (Neoproterozoic) and 456 ± 7 Ma (Late Ordovician). The magmatic zircon ages document the Kungurian age of Permian volcanic activity and contemporaneous establishment of the south-Gemeric basin. The time span of volcanic activity corresponds to the collapse of the Western Carpathian Variscan foreland which expanded southward.

Ultrathin NiO nanoflakes electrode materials for supercapacitors

NASA Astrophysics Data System (ADS)

Xiao, Huanhao; Qu, Fengyu; Wu, Xiang

2016-01-01

In this work, large scale ultrathin NiO nanoflakes grown on nickel foam have been successfully obtained by a facile, low cost and eco-friendly route under mild temperature. The average thickness of the as-obtained NiO nanoflakes is about 10 nm. And they possess large surface area of 89.56 m2 g-1 and the dominant pore size of 2.313 nm. The electrochemical properties of the obtained product were evaluated by cyclic voltammetry (CV), galvanostatic charge-discharge measurement and electrochemical impedance spectroscopy (EIS). The electrochemical tests demonstrate the highest discharge areal capacitance of 870 mF cm-2 at 1 mA cm-2 and excellent long cycle-life stability with 84.2% of its discharge areal capacitance retention after 6000 cycles at the current density of 10 mA cm-2. The remarkable electrochemical capacitive performance revealed NiO nanoflakes grown on nickel foam might be promising supercapacitor electrode materials for future energy storage applications.

Birth cohort increases in psychopathology among young Americans, 1938-2007: A cross-temporal meta-analysis of the MMPI.

PubMed

Twenge, Jean M; Gentile, Brittany; DeWall, C Nathan; Ma, Debbie; Lacefield, Katharine; Schurtz, David R

2010-03-01

Two cross-temporal meta-analyses find large generational increases in psychopathology among American college students (N=63,706) between 1938 and 2007 on the MMPI and MMPI-2 and high school students (N=13,870) between 1951 and 2002 on the MMPI-A. The current generation of young people scores about a standard deviation higher (average d=1.05) on the clinical scales, including Pd (Psychopathic Deviation), Pa (Paranoia), Ma (Hypomania), and D (Depression). Five times as many now score above common cutoffs for psychopathology, including up to 40% on Ma. The birth cohort effects are still large and significant after controlling for the L and K validity scales, suggesting that the changes are not caused by response bias. The results best fit a model citing cultural shifts toward extrinsic goals, such as materialism and status and away from intrinsic goals, such as community, meaning in life, and affiliation. Copyright 2009 Elsevier B.V. All rights reserved.

Stability and safety of MA50 intraocular lens placed in the sulcus.

PubMed

Kemp, P S; Oetting, T A

2015-11-01

To describe the safety and stability of sulcus placement of the MA50 intraocular lens (IOL). Consecutive patients with MA50 IOLs placed in the sulcus at the University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA, from 1997 to 2012 were identified. Inclusion criteria included patients with over 4 weeks of follow-up data. AEL was compared with incidence of IOL decentration using at two-tailed Student's t-test. Fifty eyes of 49 patients meeting the inclusion criteria were identified. Four weeks post-operatively, the average best-corrected visual acuity was 20/30. IOL decentration occurred in 14% of patients; patients with decentered IOLs had a significantly longer average AEL (25.37 mm) than patients whose IOL remained centered (23.94 mm, P=0.017). Other complications included uveitis-glaucoma-hyphema syndrome (12%), iritis (8%), and glaucoma (6%). There were no cases of pigment dispersion syndrome or need for lens exchange. Twelve eyes (24%) had intra-operative optic capture by the anterior capsule, none of which had post-operative decentration. The MA50 IOL is a reasonable, stable option for placement in the sulcus, with a low-risk profile; however, in eyes with longer AEL and presumably larger anterior segment, surgeons should consider placing an IOL with longer haptic distance than the MA50 to maintain centration. Optic capture of the MA50 IOL by the anterior capsule should be considered for longer eyes, as it is protective against decentration.

Methamphetamine Vaccines: Improvement through Hapten Design.

PubMed

Collins, Karen C; Schlosburg, Joel E; Bremer, Paul T; Janda, Kim D

2016-04-28

Methamphetamine (MA) addiction is a serious public health problem, and current methods to abate addiction and relapse are currently ineffective for mitigating this growing global epidemic. Development of a vaccine targeting MA would provide a complementary strategy to existing behavioral therapies, but this has proven challenging. Herein, we describe optimization of both hapten design and formulation, identifying a vaccine that elicited a robust anti-MA immune response in mice, decreasing methamphetamine-induced locomotor activity.

Comparison of the methods for measuring the Ki-67 labeling index in adrenocortical carcinoma: manual versus digital image analysis.

PubMed

Yamazaki, Yuto; Nakamura, Yasuhiro; Shibahara, Yukiko; Konosu-Fukaya, Sachiko; Sato, Naomi; Kubota-Nakayama, Fumie; Oki, Yutaka; Baba, Satoshi; Midorikawa, Sanae; Morimoto, Ryo; Satoh, Fumitoshi; Sasano, Hironobu

2016-07-01

Adrenocortical carcinoma (ACC) is a rare, highly malignant neoplasm harboring marked histologic heterogeneity. The Ki-67 labeling index (LI) is one of the most effective diagnostic and prognostic markers in ACC. However, its assessment has by no means been standardized. Therefore, in this study, we analyzed the Ki-67 LI in 18 ACC cases both by seven pathologists using microscopes (MA; manual analysis) and with digital image analysis (DIA) and also compared the Ki-67 LI obtained by selecting "hot spots" and formulating the "average" reading of the whole tumor specimen. In addition, we performed statistical analysis of the association between Ki-67 LI and the clinical and pathologic features of individual cases. The DIA was significantly correlated with MA in hot spots but not in the average fields. The Ki-67 LI in hot spots was significantly and consistently higher than that in average areas by both MA and DIA, indicating intratumoral heterogeneity. The Ki-67 LI was significantly correlated with the Weiss criteria (eosinophilic cytoplasm, nuclear atypia, atypical mitoses, and sinusoidal invasion) by any mode of evaluation. The clinical outcome was significantly better in the patients with a Ki-67 < 10% than in those with a Ki-67 > 10% by MA in hot spots. The Ki-67 LI in hot spots measured by MA best reflected the clinical and pathologic features of ACC. Employment of DIA to obtain the Ki-67 LI in ACC requires further improvement, including correction of its overestimation of the value by counting non-tumorous cells and nuclear segmentation in areas of high cell density. Copyright © 2016 Elsevier Inc. All rights reserved.

SRF test facility for the superconducting LINAC ``RAON'' — RRR property and e-beam welding

NASA Astrophysics Data System (ADS)

Jung, Yoochul; Hyun, Myungook; Joo, Jongdae; Joung, Mijoung

2015-02-01

Equipment, such as a vacuum furnace, high pressure rinse (HPR), eddy current test (ECT) and buffered chemical polishing (BCP), are installed in the superconducting radio frequency (SRF) test facility. Three different sizes of cryostats (diameters of 600 mm for a quarter wave resonator (QWR), 900 mm for a half wave resonator (HWR), and 1200 mm for single spoke resonator 1&2 (SSR 1&2)) for vertical RF tests are installed for testing cavities. We confirmed that as-received niobium sheets (ASTM B393, RRR300) good electrical properties because they showed average residual resistance ratio (RRR) values higher than 300. However, serious RRR degradation occurred after joining two pieces of Nb by e-beam welding because the average RRR values of the samples were ˜179, which was only ˜60% of as-received RRR value. From various e-beam welding experiments in which the welding current and a speed at a fixed welding voltage were changed, we confirmed that good welding results were obtained at a 53 mA welding current and a 20-mm/s welding speed at a fixed welding voltage of 150 kV.

Development of a 20 mA negative hydrogen ion source for cyclotrons

NASA Astrophysics Data System (ADS)

Etoh, H.; Onai, M.; Arakawa, Y.; Aoki, Y.; Mitsubori, H.; Sakuraba, J.; Kato, T.; Mitsumoto, T.; Yajima, S.; Hatayama, A.; Okumura, Y.

2017-08-01

A cesiated DC negative ion source has been developed for proton cyclotrons in medical applications. A continuous H- beam of 23 mA was stably extracted at an arc power of 3 kW. The beam current gradually decreases with a constant arc power and without additional Cs injection and the decay rate was about 0.03 mA (0.14%) per hour. A feed-back control system that automatically adjusts the arc power to stabilize the beam current is able to keep the beam current constant at ±0.04 mA (±0.2%).

Multi-MA reflex triode research.

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

Swanekamp, Stephen Brian; Commisso, Robert J.; Weber, Bruce V.

The Reflex Triode can efficiently produce and transmit medium energy (10-100 keV) x-rays. Perfect reflexing through thin converter can increase transmission of 10-100 keV x-rays. Gamble II experiment at 1 MV, 1 MA, 60 ns - maximum dose with 25 micron tantalum. Electron orbits depend on the foil thickness. Electron orbits from LSP used to calculate path length inside tantalum. A simple formula predicts the optimum foil thickness for reflexing converters. The I(V) characteristics of the diode can be understood using simple models. Critical current dominates high voltage triodes, bipolar current is more important at low voltage. Higher current (2.5more » MA), lower voltage (250 kV) triodes are being tested on Saturn at Sandia. Small, precise, anode-cathode gaps enable low impedance operation. Sample Saturn results at 2.5 MA, 250 kV. Saturn dose rate could be about two times greater. Cylindrical triode may improve x-ray transmission. Cylindrical triode design will be tested at 1/2 scale on Gamble II. For higher current on Saturn, could use two cylindrical triodes in parallel. 3 triodes in parallel require positive polarity operation. 'Triodes in series' would improve matching low impedance triodes to generator. Conclusions of this presentation are: (1) Physics of reflex triodes from Gamble II experiments (1 MA, 1 MV) - (a) Converter thickness 1/20 of CSDA range optimizes x-ray dose; (b) Simple model based on electron orbits predicts optimum thickness from LSP/ITS calculations and experiment; (c) I(V) analysis: beam dynamics different between 1 MV and 250 kV; (2) Multi-MA triode experiments on Saturn (2.5 MA, 250 kV) - (a) Polarity inversion in vacuum, (b) No-convolute configuration, accurate gap settings, (c) About half of current produces useful x-rays, (d) Cylindrical triode one option to increase x-ray transmission; and (3) Potential to increase Saturn current toward 10 MA, maintaining voltage and outer diameter - (a) 2 (or 3) cylindrical triodes in parallel, (b) Triodes in series to improve matching, (c) These concepts will be tested first on Gamble II.« less

Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

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

Tao, Yinghua; Chen, Guang-Hong; Hacker, Timothy A.

Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan wasmore » performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937.9% for the 500 mA FBP, 25 mA SIR, and 25 mA FBP, respectively. In numerical simulations, SIR mitigated streak artifacts in the low dose data and yielded flow maps with mean error <7% and standard deviation <9% of mean, for 30×30 pixel ROIs (12.9 × 12.9 mm{sup 2}). In comparison, low dose FBP flow errors were −38% to +258%, and standard deviation was 6%–93%. Additionally, low dose SIR achieved 4.6 times improvement in flow map CNR{sup 2} per unit input dose compared to low dose FBP. Conclusions: SIR reconstruction can reduce image noise and mitigate streaking artifacts caused by photon starvation in dynamic CT myocardial perfusion data sets acquired at low dose (low tube current), and improve perfusion map quality in comparison to FBP reconstruction at the same dose.« less

Identifying the complex melting reaction from 20 Ma to 14 Ma in Tsona leucogranite in Southern Tibet: geochemistry, zircon U-Pb chronology and Hf isotopes evidence

NASA Astrophysics Data System (ADS)

Shi, Qingshang; Zhao, Zhidan; Liu, Dong; Zhu, Di-Cheng

2017-04-01

The Miocene leucogranites, the record of the evolution of the Himalayan-Tibetan Orogen, extensively intruded the Greater Himalayan Sequence (GHS), and distributed along the South Tibetan Detachment System (STDS) (Guo and Wilson, 2012). Here we present a study of geochemistry, zircon U-Pb chronology and Hf isotopes on the Yamarong leucogranites from Tsona area, Eastern Himalaya, to explore the petrogenesis of the rocks, including melting condition and mechanism, and source of fluid within the magmatism through time. Our new results include: (1) The age of the Yamarong leucogranites range from 14 Ma to 20 Ma (YM1510-1 = 19.7 ± 0.1 Ma, n = 13; YM1502-1 = 17.5 ± 0.1 Ma, n = 12; YM1412 =14.2 ± 0.1 Ma, n = 18), which suggest that the anataxis processes have lasted for more than 6 Ma. (2) The geochemical features are different between the rocks with changing ages, especially between 20 Ma and 17 Ma. The Rb/Sr value of 20 Ma leucogranites (4.1-6.84) is lower than that of 17 Ma samples (5.12-19.02). The 20 Ma leucogranites have higher Ba contents (188-337 ppm) than that of 17 Ma rocks (50-158ppm), which exhibit different trends in the Rb/Sr versus Ba plot, and reveal different melting reaction from 20 Ma to 17 Ma. (Inger and Harris, 1993) (3) The ɛHf(t) isotopes of 20 Ma leucogranites are lower (average ɛHf(t) = -12.5) than that of 17 Ma ones (average ɛHf(t) = -10), which implies differential dissolution of inherited zircon during two partial melting events possibly due to different fluid contribution (Gao et al., 2017); (4) The positive linear relationship of LREEs versus Th in the rocks, with relatively higher contents of Th and LREEs in the 20 Ma, and lower in the 17 Ma leucogranites, which suggests the relationship were mostly controlled by monazite. And this further indicates more monazite was dissolved from the source region in the early stage (˜20Ma) than the later (17Ma) (Gao et al., 2017). In summary, our study provides new evidence for the complex melting mechanism, from fluid-fluxed melting at ˜20 Ma to later fluid-absent melting at ˜17 Ma of muscovite in the metasedimentary sources. The ˜20 Ma magmatism in Tsona area may represent the early stage of exhumation, with more fluid possibly came from either the Lesser Himalayan sequence (LHS) or the Cretaceous - Paleogene molasses beneath the along - stike extrapolation of the Yamarong leucogranties source (Harrison and Wielicki, 2016). Reference: Gao L-E, Zeng L, Asimow PD, 2017. Contrasting geochemical signatures of fluid-absent versus fluid-fluxed melting of muscovite in metasedimentary sources: The Himalayan leucogranites. Geology, 45(1):39-42. Guo Z, Wilson M, 2012. The Himalayan leucogranites: Constraints on the nature of their crustal source region and geodynamic setting. Gondwana Research, 22(2): 360-376. Harrison TM, Wielicki MM, 2016. From the Hadean to the Himalaya: 4.4 Ga of felsic terrestrial magmatism. American Mineralogist, 101(6): 1348-1359. Inger S, Harris N, 1993. Geochemical Constraints on Leucogranite Magmatism in the Langtang Valley, Nepal Himalaya. Journal of Petrology, 34(2): 345-368.

Non-Dipole Features of the Geomagnetic Field May Persist for Millions of Years

NASA Astrophysics Data System (ADS)

Biasi, J.; Kirschvink, J. L.

2017-12-01

Here we present paleointensity results from within the South Atlantic Anomaly (SAA), which is a large non-dipole feature of the geomagnetic field. Within the area of the SAA, anomalous declinations, inclinations, and intensities are observed. Our results suggest that the SAA has been present for at least 5 Ma. This is orders-of-magnitude greater than any previous estimate, and suggests that some non-dipole features do not `average out' over geologic time, which is a fundamental assumption in all paleodirectional studies. The SAA has been steadily growing in size since the first magnetic measurements were made in the South Atlantic, and it is widely believed to have appeared 400 years ago. Recent studies from South Africa (Tarduno et al. (2015)) and Tristan da Cunha (Shah et al. (2016)) have suggested that the SAA has persisted for 1 ka and 96 ka respectively. We conducted paleointensity (PI) experiments on basaltic lavas from James Ross Island, on the Antarctic Peninsula. This large shield volcano has been erupting regularly over the last 6+ Ma (dated via Ar/Ar geochronology), and therefore contains the most complete volcanostratigraphic record in the south Atlantic. Our PI experiments used the Thellier-Thellier method, the IZZI protocol, and the same selection criteria as the Lawrence et al. (2009) study of Ross Island lavas (near McMurdo Station), which is the only comparable PI study on the Antarctic continent. We determined an average paleointensity at JRI of 13.8±5.2 μT, which is far lower than what we would expect from a dipole field (55 μT). In addition, this is far lower than the current value over James Ross Island of 36 μT. These results support the following conclusions: The time-averaged field model of Juarez et al. (1998) and Tauxe et al. (2013) is strongly favored by our PI data. The SAA has persisted over James Ross Island for at least 5 Ma, and has not drifted significantly over that time. The strength of non-dipole features such as the SAA scales with the dipole moment of the earth. Non-dipole features like the SAA can survive geomagnetic reversals. The fundamental assumption that non-dipole features of the geomagnetic field are `averaged out' over geologic timescales needs to be reconsidered.

42 CFR 423.279 - National average monthly bid amount.

Code of Federal Regulations, 2010 CFR

2010-10-01

... bid amounts for each prescription drug plan (not including fallbacks) and for each MA-PD plan...(h) of the Act. (b) Calculation of weighted average. (1) The national average monthly bid amount is a....258(c)(1) of this chapter) and the denominator equal to the total number of Part D eligible...

42 CFR 423.279 - National average monthly bid amount.

Code of Federal Regulations, 2011 CFR

2011-10-01

... bid amounts for each prescription drug plan (not including fallbacks) and for each MA-PD plan...(h) of the Act. (b) Calculation of weighted average. (1) The national average monthly bid amount is a....258(c)(1) of this chapter) and the denominator equal to the total number of Part D eligible...

Player Monitoring in Indoor Team Sports: Concurrent Validity of Inertial Measurement Units to Quantify Average and Peak Acceleration Values

PubMed Central

Roell, Mareike; Roecker, Kai; Gehring, Dominic; Mahler, Hubert; Gollhofer, Albert

2018-01-01

The increasing interest in assessing physical demands in team sports has led to the development of multiple sports related monitoring systems. Due to technical limitations, these systems primarily could be applied to outdoor sports, whereas an equivalent indoor locomotion analysis is not established yet. Technological development of inertial measurement units (IMU) broadens the possibilities for player monitoring and enables the quantification of locomotor movements in indoor environments. The aim of the current study was to validate an IMU measuring by determining average and peak human acceleration under indoor conditions in team sport specific movements. Data of a single wearable tracking device including an IMU (Optimeye S5, Catapult Sports, Melbourne, Australia) were compared to the results of a 3D motion analysis (MA) system (Vicon Motion Systems, Oxford, UK) during selected standardized movement simulations in an indoor laboratory (n = 56). A low-pass filtering method for gravity correction (LF) and two sensor fusion algorithms for orientation estimation [Complementary Filter (CF), Kalman-Filter (KF)] were implemented and compared with MA system data. Significant differences (p < 0.05) were found between LF and MA data but not between sensor fusion algorithms and MA. Higher precision and lower relative errors were found for CF (RMSE = 0.05; CV = 2.6%) and KF (RMSE = 0.15; CV = 3.8%) both compared to the LF method (RMSE = 1.14; CV = 47.6%) regarding the magnitude of the resulting vector and strongly emphasize the implementation of orientation estimation to accurately describe human acceleration. Comparing both sensor fusion algorithms, CF revealed slightly lower errors than KF and additionally provided valuable information about positive and negative acceleration values in all three movement planes with moderate to good validity (CV = 3.9 – 17.8%). Compared to x- and y-axis superior results were found for the z-axis. These findings demonstrate that IMU-based wearable tracking devices can successfully be applied for athlete monitoring in indoor team sports and provide potential to accurately quantify accelerations and decelerations in all three orthogonal axes with acceptable validity. An increase in accuracy taking magnetometers in account should be specifically pursued by future research. PMID:29535641

Will Medicare Advantage payment reforms impact plan rebates and enrollment?

PubMed

Nicholas, Lauren Hersch

2014-01-01

To assess the relationship between Medicare Advantage (MA) plan rebates and enrollment and simulate the effects of Affordable Care Act (ACA) payment reforms. First difference regressions of county-level MA payment and enrollment data from CMS from 2006 to 2010. A $10 decrease in the per member/per month rebate to MA plans was associated with a 0.20 percentage point (0.9%) decrease in MA penetration (P < .001) and a 7.1% decline in the average MA enrollee's risk score (P < .001). These effects are small overall, but larger in counties with low levels of traditional Medicare spending; a $10 decrease in monthly rebates was associated with a 0.64 percentage point decline in MA penetration and a 10% decrease in risk score. ACA reforms are predicted to reduce the level of rebates in lower-spending counties, leading to enrollment decreases of 1.7 to 1.9 percentage points in the lowest-spending counties. The simulation predicts that the disenrollment would come from MA enrollees with higher risk scores. MA enrollment responds to availability of supplemental benefits supported by rebates. ACA provisions designed to lower MA spending will predominantly affect Medicare beneficiaries living in counties where MA plans may be unable to offer a comparable product at a price similar to that of traditional Medicare.

Increased cutaneous wound healing effect of biodegradable liposomes containing madecassoside: preparation optimization, in vitro dermal permeation, and in vivo bioevaluation.

PubMed

Li, Zehao; Liu, Meifeng; Wang, Huijuan; Du, Song

2016-01-01

Madecassoside (MA) is highly potent in treating skin disorders such as wounds and psoriasis. However, the topical wound healing effect of MA was hampered by its poor membrane permeability. In order to overcome this shortcoming, MA liposomes were designed and prepared by a double-emulsion method to enhance transdermal and wound healing effects. In this study, response surface methodology was adopted to yield the optimal preparation conditions of MA double-emulsion liposomes with average particle size of 151 nm and encapsulation efficiency of 70.14%. Moreover, MA double-emulsion liposomes demonstrated superior stability and homogeneous appearance in 5 months; their leakage rate was <12% even at 37°C and <5% at 4°C within 1 month. In vitro skin permeation, skin distribution, and burn wound healing of MA liposomal formulations were conducted for the first time to evaluate MA delivery efficiency and wound healing effect. The transdermal property and wound cure effect of MA double-emulsion liposomes were superior to those of MA film dispersion liposomes, and both the methods were endowed with an excellent performance by polyethylene glycol modification. In conclusion, double-emulsion liposome formulation was an applicable and promising pharmaceutical preparation for enhancing MA delivery toward wound healing effect and improving wound-healing progress.

Metal coordination polymer derived mesoporous Co3O4 nanorods with uniform TiO2 coating as advanced anodes for lithium ion batteries

NASA Astrophysics Data System (ADS)

Geng, Hongbo; Ang, Huixiang; Ding, Xianguang; Tan, Huiteng; Guo, Guile; Qu, Genlong; Yang, Yonggang; Zheng, Junwei; Yan, Qingyu; Gu, Hongwei

2016-01-01

In this work, a one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g-1, good cycling stability (around 803 mA h g-1 at a current density of 200 mA g-1 after 100 cycles), and stable rate performance (around 520 mA h g-1 at a current density of 1000 mA g-1). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling.In this work, a one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g-1, good cycling stability (around 803 mA h g-1 at a current density of 200 mA g-1 after 100 cycles), and stable rate performance (around 520 mA h g-1 at a current density of 1000 mA g-1). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08570e

Facile synthesis of PdSx/C porous nanospheres and their applications for ethanol oxidation reaction

NASA Astrophysics Data System (ADS)

Zhang, Qiang; Zhang, Fuhua; Ma, Xuemei; Zheng, Yiqun; Hou, Shifeng

2016-12-01

We report a facile approach for the synthesis of carbon-supported palladium polysulphide porous nanospheres (PdSx/C) and their applications for ethanol oxidation reaction. Typical synthesis started with generation of palladium/poly (3,4-ethylenedioxythiophene)(Pd/PEDOT) nanospheres, followed by a calcination process at an optimized temperature to form PdSx/C, with an average size of 2.47 ± 0.60 and 50 nm of PdSx nanoparticles and carbon porous nanospheres, respectively. Various techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical techniques were performed to characterize their morphologies, compositions and structures. In contrary to most Pd-based electrochemical catalysts that could be easily poised with trace sulfur during the catalytic oxidation process, the as-prepared PdSx/C porous nanospheres exhibited high electrocatalytic activities and stabilities for the electrochemical catalytic oxidation of ethanol in alkaline medium. In particular, the forward peak current intensity achieved 162.1 mA mg-1 and still maintained at 46.7 mA mg-1 even after 1000 cycles. This current work not only offers a novel type of fuel-cell catalyst for ethanol oxidation reaction, but also provides a possible route for solving the sulfur-poisoning problem in catalysis.

Inter- and Intra-individual Variability in Response to Transcranial Direct Current Stimulation (tDCS) at Varying Current Intensities.

PubMed

Chew, Taariq; Ho, Kerrie-Anne; Loo, Colleen K

2015-01-01

Translation of transcranial direct current stimulation (tDCS) from research to clinical practice is hindered by a lack of consensus on optimal stimulation parameters, significant inter-individual variability in response, and in sufficient intra-individual reliability data. Inter-individual differences in response to anodal tDCS at a range of current intensities were explored. Intra-individual reliability in response to anodal tDCS across two identical sessions was also investigated. Twenty-nine subjects participated in a crossover study. Anodal-tDCS using four different current intensities (0.2, 0.5, 1 and 2 mA), with an anode size of 16 cm2, was tested. The 0.5 mA condition was repeated to assess intra-individual variability. TMS was used to elicit 40 motor-evoked potentials (MEPs) before 10 min of tDCS, and 20 MEPs at four time-points over 30 min following tDCS. ANOVA revealed no main effect of TIME for all conditions except the first 0.5 mA condition, and no differences in response between the four current intensities. Cluster analysis identified two clusters for the 0.2 and 2 mA conditions only. Frequency distributions based on individual subject responses (excitatory, inhibitory or no response) to each condition indicate possible differential responses between individuals to different current intensities. Test-retest reliability was negligible (ICC(2,1) = -0.50). Significant inter-individual variability in response to tDCS across a range of current intensities was found. 2 mA and 0.2 mA tDCS were most effective at inducing a distinct response. Significant intra-individual variability in response to tDCS was also found. This has implications for interpreting results of single-session tDCS experiments. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Tripling of Methamphetamine/Amphetamine Use among Homeless and Marginally Housed Persons, 1996–2003

PubMed Central

Colfax, Grant; Moss, Andrew R.; Bangsberg, David R.; Hahn, Judith A.

2007-01-01

Methamphetamine/amphetamine (MA)-related morbidity and mortality has been increasing in the United States. MA use is associated with high-risk sexual behavior and syringe-sharing practices. Homeless and marginalized housed persons (H/M) have high rates of substance use and mental health disorders. Little is known about trends of MA use among the H/M. The objective of this study was to quantify increases in MA use among H/M in San Francisco and to determine which demographic and behavioral subgroups have experienced the greatest increases in MA use. We conducted serial cross-sectional population-based studies in three waves: 1996–1997, 1999–2000, and 2003 and studied 2,348 H/M recruited at shelters and lunch lines. The main outcome was self-reported current (30-day) MA use. We found a tripling of current MA use among H/M persons from 1996 to 2003, with a sevenfold increase in smoked MA use. MA use doubled to tripled in most demographic and behavioral subgroups, whereas it quadrupled in those under age 35, and there was a fivefold increase among HIV-infected persons. The increase in MA use among H/M places a vulnerable population at additional increased risk for HIV infection and MA-use related morbidity and mortality. Among HIV-infected H/M, the increase in MA use has important public health implications for the development and secondary transmission of drug-resistant HIV caused by synergistic neurocognitive decline, poor adherence to HIV medications, and increased sexual risk behavior. Clinicians caring for H/M persons should inquire about MA use, refer interested MA users to MA dependence treatment programs and provide targeted HIV sexual risk reduction counseling. For HIV-infected H/M MA users, clinicians should closely monitor adherence to HIV or other chronic medications, to avoid unnecessary morbidity and mortality. Further research is needed to elucidate the most effective prevention and treatment for MA use and dependence among the H/M. PMID:18163214

Superior cycle performance and high reversible capacity of SnO2/graphene composite as an anode material for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Liu, Lilai; An, Maozhong; Yang, Peixia; Zhang, Jinqiu

2015-03-01

SnO2/graphene composite with superior cycle performance and high reversible capacity was prepared by a one-step microwave-hydrothermal method using a microwave reaction system. The SnO2/graphene composite was characterized by X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, transmission electron microscopy and high resolution transmission electron microscopy. The size of SnO2 grains deposited on graphene sheets is less than 3.5 nm. The SnO2/graphene composite exhibits high capacity and excellent electrochemical performance in lithium-ion batteries. The first discharge and charge capacities at a current density of 100 mA g-1 are 2213 and 1402 mA h g-1 with coulomb efficiencies of 63.35%. The discharge specific capacities remains 1359, 1228, 1090 and 1005 mA h g-1 after 100 cycles at current densities of 100, 300, 500 and 700 mA g-1, respectively. Even at a high current density of 1000 mA g-1, the first discharge and charge capacities are 1502 and 876 mA h g-1, and the discharge specific capacities remains 1057 and 677 mA h g-1 after 420 and 1000 cycles, respectively. The SnO2/graphene composite demonstrates a stable cycle performance and high reversible capacity for lithium storage.

Analysis of the processes occurring in a submicrosecond discharge with a linear current density of up to 3 MA/cm through a thick-wall stainless-steel electrode

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

Branitsky, A. V.; Grabovski, E. V.; Dzhangobegov, V. V.

The state of conductors carrying a megampere current from the generator to the load is studied experimentally. It is found that the plasma produced from cylindrical stainless-steel tubes during the passage of a submicrosecond current pulse with a linear density of 3 MA/cm expands with a velocity of 5.5 km/s. Numerical results on the diffusion of the magnetic field induced by a current with a linear density of 1–3MA/cm into metal electrodes agree with the experimental data on the penetration time of the magnetic field. For a linear current density of 3.1 MA/cm, the experimentally determined electric field strength onmore » the inner surface of the tube is 4 kV/cm. The calculated electric field strength on the inner surface of the tube turns out to be two times higher, which can be explained by plasma production on the outer and inner surfaces of the electrode.« less

Performance of an electron gun for a high-brightness X-ray generator.

PubMed

Sugimura, Takashi; Ohsawa, Satoshi; Ikeda, Mitsuo

2008-05-01

A prototype thermionic electron gun for a high-brightness X-ray generator has been developed. Its extraction voltage and design current are 60 kV and 100 mA (DC), respectively. The X-ray generator aims towards a maximum brilliance of 60 kW mm(-2). The beam sizes at the rotating anticathode must therefore be within 1.0 mm x 0.1 mm and a small beam emittance is required. The fabricated electron gun optimizes an aperture grid and a Whenelt electrode. The performance of the prototype electron gun measured using pulsed-beam tests is as follows: maximum beam current, 85.7 mA; beam focus size at the rotating anticathode, 0.79 mm x 0.13 mm. In DC beam tests, FWHM beam sizes were measured to be 0.65 mm x 0.08 mm at the rotating anticathode with a beam current of 45 mA. The beam current recently reached approximately 60 mA with some thermal problems.

Self-administration of (+)-methamphetamine and (+)-pseudoephedrine, alone and combined, by rhesus monkeys.

PubMed

Freeman, Kevin B; Wang, Zhixia; Woolverton, William L

2010-04-01

(+)-Methamphetamine (MA) is an illicit psychostimulant that can be synthesized from the nonprescription nasal decongestant, (+)-pseudoephedrine (PE). While MA is widely abused, PE appears to have little or no abuse liability in currently available formulations. However, PE produces centrally-mediated dopaminergic effects that are linked to the reinforcing effects of MA and other illicit psychostimulants and has been reported to function as a positive reinforcer in non-human primates. There has yet to be an assessment of the relative reinforcing effects of MA and PE. Therefore, the current study compared the reinforcing potency and strength of MA and PE, alone and combined, in four rhesus monkeys that were allowed to self-administer MA (0.003-0.3 mg/kg/inj), PE (0.1-3.0 mg/kg/inj), or combinations of the two under a progressive-ratio schedule of reinforcement. (+)-Methamphetamine functioned as a positive reinforcer in a dose-dependent manner. (+)-Pseudoephedrine also functioned as a positive reinforcer, but was less potent than MA. There were no differences in maximum injections between MA, PE, or any of the combinations of the two. Dose-addition analysis and the interaction index indicated that combinations of PE and MA were either additive or sub-additive in their reinforcing effects. These results suggest that, while MA is a more potent reinforcer than PE, the two drugs are comparable in terms of reinforcing strength. However, MA and PE do not appear to interact in a manner that enhances their relative reinforcing effects. Published by Elsevier Inc.

Self-administration of (+)-methamphetamine and (+)-pseudoephedrine, alone and combined, by rhesus monkeys

PubMed Central

Freeman, Kevin B.; Wang, Zhixia; Woolverton, William L.

2010-01-01

(+)-Methamphetamine (MA) is an illicit psychostimulant that can be synthesized from the nonprescription nasal decongestant, (+)-pseudoephedrine (PE). While MA is widely abused, PE appears to have little or no abuse liability in currently available formulations. However, PE produces centrally-mediated dopaminergic effects that are linked to the reinforcing effects of MA and other illicit psychostimulants and has been reported to function as a positive reinforcer in non-human primates. There has yet to be an assessment of the relative reinforcing effects of MA and PE. Therefore, the current study compared the reinforcing potency and strength of MA and PE, alone and combined, in four rhesus monkeys that were allowed to self-administer MA (0.003-0.3 mg/kg/inj), PE (0.1-3.0 mg/kg/inj), or combinations of the two under a progressive-ratio schedule of reinforcement. (+)-Methamphetamine functioned as a positive reinforcer in a dose-dependent manner. (+)-Pseudoephedrine also functioned as a positive reinforcer, but was less potent than MA. There were no differences in maximum injections between MA, PE, or any of the combinations of the two. Dose-addition analysis and the interaction index indicated that combinations of PE and MA were either additive or sub-additive in their reinforcing effects. These results suggest that, while MA is a more potent reinforcer than PE, the two drugs are comparable in terms of reinforcing strength. However, MA and PE do not appear to interact in a manner that enhances their relative reinforcing effects. PMID:20100506

A diversity index for model space selection in the estimation of benchmark and infectious doses via model averaging.

PubMed

Kim, Steven B; Kodell, Ralph L; Moon, Hojin

2014-03-01

In chemical and microbial risk assessments, risk assessors fit dose-response models to high-dose data and extrapolate downward to risk levels in the range of 1-10%. Although multiple dose-response models may be able to fit the data adequately in the experimental range, the estimated effective dose (ED) corresponding to an extremely small risk can be substantially different from model to model. In this respect, model averaging (MA) provides more robustness than a single dose-response model in the point and interval estimation of an ED. In MA, accounting for both data uncertainty and model uncertainty is crucial, but addressing model uncertainty is not achieved simply by increasing the number of models in a model space. A plausible set of models for MA can be characterized by goodness of fit and diversity surrounding the truth. We propose a diversity index (DI) to balance between these two characteristics in model space selection. It addresses a collective property of a model space rather than individual performance of each model. Tuning parameters in the DI control the size of the model space for MA. © 2013 Society for Risk Analysis.

Stability and safety of MA50 intraocular lens placed in the sulcus

PubMed Central

Kemp, P S; Oetting, T A

2015-01-01

Purpose To describe the safety and stability of sulcus placement of the MA50 intraocular lens (IOL). Patients and methods Consecutive patients with MA50 IOLs placed in the sulcus at the University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA, from 1997 to 2012 were identified. Inclusion criteria included patients with over 4 weeks of follow-up data. AEL was compared with incidence of IOL decentration using at two-tailed Student's t-test. Results Fifty eyes of 49 patients meeting the inclusion criteria were identified. Four weeks post-operatively, the average best-corrected visual acuity was 20/30. IOL decentration occurred in 14% of patients; patients with decentered IOLs had a significantly longer average AEL (25.37 mm) than patients whose IOL remained centered (23.94 mm, P=0.017). Other complications included uveitis-glaucoma-hyphema syndrome (12%), iritis (8%), and glaucoma (6%). There were no cases of pigment dispersion syndrome or need for lens exchange. Twelve eyes (24%) had intra-operative optic capture by the anterior capsule, none of which had post-operative decentration. Conclusion The MA50 IOL is a reasonable, stable option for placement in the sulcus, with a low-risk profile; however, in eyes with longer AEL and presumably larger anterior segment, surgeons should consider placing an IOL with longer haptic distance than the MA50 to maintain centration. Optic capture of the MA50 IOL by the anterior capsule should be considered for longer eyes, as it is protective against decentration. PMID:26139047

An investigation into the magnitude of the current window and perception of transcutaneous electrical nerve stimulation (TENS) sensation at various frequencies and body sites in healthy human participants.

PubMed

Hughes, Nicola; Bennett, Michael I; Johnson, Mark I

2013-02-01

Strong nonpainful transcutaneous electrical nerve stimulation (TENS) is prerequisite to a successful analgesic outcome although the ease with which this sensation is achieved is likely to depend on the magnitude of current amplitude (mA) between sensory detection threshold (SDT) and pain threshold, that is, the current window. To measure the current window and participant's perception of the comfort of the TENS sensation at different body sites. A repeated measure cross-over study was conducted using 30 healthy adult volunteers. Current amplitudes (mA) of TENS [2 pulses per second (pps); 30 pps; 80 pps] at SDT, pain threshold, and strong nonpainful intensities were measured at the tibia (bone), knee joint (connective tissue), lower back [paraspinal (skeletal) muscle], volar surface of forearm (nerve) and waist (fat). The amplitude to achieve a strong nonpainful intensity was represented as a percentage of the current window. Data were analyzed using repeated measures analysis of variance. Effects were detected for body site and frequency for SDT (P<0.001, P=0.018, respectively), current window (P<0.001, P<0.001, respectively), and strong nonpainful TENS as a percentage of the current window (P=0.002, P<0.001, respectively). The current window was larger for the knee joint compared with tibia (difference [95% confidence interval]=12.76 mA [4.25, 21.28]; P=0.001) and forearm (10.33 mA [2.62, 18.40]; P=0.006), and for the lower back compared with tibia (12.10 mA [1.65, 22.52]; P=0.015) and forearm (9.65 mA [1.06, 18.24]; P=0.019). The current window was larger for 2 pps compared with 30 pps (P<0.001) and 80 pps (P<0.001). Participants rated strong nonpainful TENS as most comfortable at the lower back (P<0.001) and least comfortable at the tibia and forearm (P<0.001). TENS is most comfortable and easiest to titrate to a strong nonpainful intensity when applied over areas of muscle and soft tissue.

Average sedimentary rock rare Earth element patterns and crustal evolution: Some observations and implications from the 3800 Ma ISUA supracrustal belt, West Greenland

NASA Technical Reports Server (NTRS)

Dymek, R. F.; Boak, J. L.; Gromet, L. P.

1983-01-01

Rare earth element (REE) data is given on a set of clastic metasediments from the 3800 Ma Isua Supracrustal belt, West Greenland. Each of two units from the same sedimentary sequence has a distinctive REE pattern, but the average of these rocks bears a very strong resemblance to the REE pattern for the North American Shale Composite (NASC), and departs considerably from previous estimates of REE patterns in Archaean sediments. The possibility that the source area for the Isua sediments resembled that of the NASC is regarded as highly unlikely. However, REE patterns like that in the NASC may be produced by sedimentary recycling of material yielding patterns such as are found at Isua. The results lead to the following tentative conclusions: (1) The REE patterns for Isua Seq. B MBG indicate the existence of crustal materials with fractionated REE and negative Eu anomalies at 3800 Ma, (2) The average Seq. B REE pattern resembles that of the North American Shale Composite (NASC), (3) If the Seq. B average is truly representative of its crustal sources, then this early crust could have been extensively differentiated. In this regard, a proper understanding of the NASC pattern, and its relationship to post-Archaean crustal REE reservoirs, is essential, (4) The Isua results may represent a local effect.

MA130301GT catalogue of Martian impact craters and advanced evaluation of crater detection algorithms using diverse topography and image datasets

NASA Astrophysics Data System (ADS)

Salamunićcar, Goran; Lončarić, Sven; Pina, Pedro; Bandeira, Lourenço; Saraiva, José

2011-01-01

Recently, all the craters from the major currently available manually assembled catalogues have been merged into the catalogue with 57 633 known Martian impact craters (MA57633GT). In addition, the work on crater detection algorithm (CDA), developed to search for still uncatalogued impact craters using 1/128° MOLA data, resulted in MA115225GT. In parallel with this work another CDA has been developed which resulted in the Stepinski catalogue containing 75 919 craters (MA75919T). The new MA130301GT catalogue presented in this paper is the result of: (1) overall merger of MA115225GT and MA75919T; (2) 2042 additional craters found using Shen-Castan based CDA from the previous work and 1/128° MOLA data; and (3) 3129 additional craters found using CDA for optical images from the previous work and selected regions of 1/256° MDIM, 1/256° THEMIS-DIR, and 1/256° MOC datasets. All craters from MA130301GT are manually aligned with all used datasets. For all the craters that originate from the used catalogues (Barlow, Rodionova, Boyce, Kuzmin, Stepinski) we integrated all the attributes available in these catalogues. With such an approach MA130301GT provides everything that was included in these catalogues, plus: (1) the correlation between various morphological descriptors from used catalogues; (2) the correlation between manually assigned attributes and automated depth/diameter measurements from MA75919T and our CDA; (3) surface dating which has been improved in resolution globally; (4) average errors and their standard deviations for manually and automatically assigned attributes such as position coordinates, diameter, depth/diameter ratio, etc.; and (5) positional accuracy of features in the used datasets according to the defined coordinate system referred to as MDIM 2.1, which incorporates 1232 globally distributed ground control points, while our catalogue contains 130 301 cross-references between each of the used datasets. Global completeness of MA130301GT is up to ˜ D≥2 km (it contains 85 783 such craters, while the smallest D is 0.924 km). This is a considerable improvement in comparison with the completeness of the Rodionova (˜10 km), Barlow (˜5 km) and Stepinski (˜3 km) catalogues. An accompanying result to the new catalogue is a contribution to the evaluation of CDAs - the following methods have been developed: (1) a new context-aware method for the advanced automated registration of craters with GT catalogues; (2) a new method for manual registration of newly found craters into GT catalogues; and (3) additional new accompanying methods for objective evaluation of CDAs using different datasets including optical images.

Individualized Low-Amplitude Seizure Therapy: Minimizing Current for Electroconvulsive Therapy and Magnetic Seizure Therapy.

PubMed

Peterchev, Angel V; Krystal, Andrew D; Rosa, Moacyr A; Lisanby, Sarah H

2015-08-01

Electroconvulsive therapy (ECT) at conventional current amplitudes (800-900 mA) is highly effective but carries the risk of cognitive side effects. Lowering and individualizing the current amplitude may reduce side effects by virtue of a less intense and more focal electric field exposure in the brain, but this aspect of ECT dosing is largely unexplored. Magnetic seizure therapy (MST) induces a weaker and more focal electric field than ECT; however, the pulse amplitude is not individualized and the minimum amplitude required to induce a seizure is unknown. We titrated the amplitude of long stimulus trains (500 pulses) as a means of determining the minimum current amplitude required to induce a seizure with ECT (bilateral, right unilateral, bifrontal, and frontomedial electrode placements) and MST (round coil on vertex) in nonhuman primates. Furthermore, we investigated a novel method of predicting this amplitude-titrated seizure threshold (ST) by a non-convulsive measurement of motor threshold (MT) using single pulses delivered through the ECT electrodes or MST coil. Average STs were substantially lower than conventional pulse amplitudes (112-174 mA for ECT and 37.4% of maximum device amplitude for MST). ST was more variable in ECT than in MST. MT explained 63% of the ST variance and is hence the strongest known predictor of ST. These results indicate that seizures can be induced with less intense electric fields than conventional ECT that may be safer; efficacy and side effects should be evaluated in clinical studies. MT measurement could be a faster and safer alternative to empirical ST titration for ECT and MST.

Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

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

Bakar, Khomsaton Abu; Zulkafli,; Hashim, Siti A'aisah

2014-09-03

In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev butmore » at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD{sub 5}, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.« less

All-MOCVD-grown BH laser on P-InP substrates

NASA Astrophysics Data System (ADS)

Nishimura, Tadashi; Ishimura, E.; Nakajima, Yasuo; Tada, Hitoshi; Kimura, T.; Ohkura, Y.; Goto, Katsuhiko; Omura, Etsuji; Aiga, Masao

1993-07-01

A very low cw threshold current of 2.5 mA ( 25 degree(s)C) and 8.0 mA ( 80 degree(s)C) with high reliability has been realized in the all-MOCVD grown BH lasers on p-InP substrates. A strained MQW active layer of 1.3 micrometers wavelength and the precise carrier confinement buried structure by MOCVD is employed for the BH lasers. The excellent potential of long lifetime of the all-MOCVD grown laser has also been confirmed. After the high temperature and the high current (100 degree(s)C, 200 mA) aging test, no significant degradation is observed which is comparable with the well-established LPE grown lasers. The BH laser is also operating stably over 3700 hrs under the APC condition of 50 degree(s)C, 10 mW. Finally, an extremely uniform 10-element all-MOCVD grown LD array is demonstrated, which has the threshold current uniformity of 2.4 +/- 0.1 mA ( 25 degree(s)C) and 9.2 +/- 0.2 mA ( 80 degree(s)C). The growth mechanism in the MOCVD is also described.

DMS-MaPseq for genome-wide or targeted RNA structure probing in vivo.

PubMed

Zubradt, Meghan; Gupta, Paromita; Persad, Sitara; Lambowitz, Alan M; Weissman, Jonathan S; Rouskin, Silvi

2017-01-01

Coupling of structure-specific in vivo chemical modification to next-generation sequencing is transforming RNA secondary structure studies in living cells. The dominant strategy for detecting in vivo chemical modifications uses reverse transcriptase truncation products, which introduce biases and necessitate population-average assessments of RNA structure. Here we present dimethyl sulfate (DMS) mutational profiling with sequencing (DMS-MaPseq), which encodes DMS modifications as mismatches using a thermostable group II intron reverse transcriptase. DMS-MaPseq yields a high signal-to-noise ratio, can report multiple structural features per molecule, and allows both genome-wide studies and focused in vivo investigations of even low-abundance RNAs. We apply DMS-MaPseq for the first analysis of RNA structure within an animal tissue and to identify a functional structure involved in noncanonical translation initiation. Additionally, we use DMS-MaPseq to compare the in vivo structure of pre-mRNAs with their mature isoforms. These applications illustrate DMS-MaPseq's capacity to dramatically expand in vivo analysis of RNA structure.

Low-power transcutaneous current stimulator for wearable applications.

PubMed

Karpul, David; Cohen, Gregory K; Gargiulo, Gaetano D; van Schaik, André; McIntyre, Sarah; Breen, Paul P

2017-10-03

Peripheral neuropathic desensitization associated with aging, diabetes, alcoholism and HIV/AIDS, affects tens of millions of people worldwide, and there is little or no treatment available to improve sensory function. Recent studies that apply imperceptible continuous vibration or electrical stimulation have shown promise in improving sensitivity in both diseased and healthy participants. This class of interventions only has an effect during application, necessitating the design of a wearable device for everyday use. We present a circuit that allows for a low-power, low-cost and small form factor implementation of a current stimulator for the continuous application of subthreshold currents. This circuit acts as a voltage-to-current converter and has been tested to drive + 1 to - 1 mA into a 60 k[Formula: see text] load from DC to 1 kHz. Driving a 60 k[Formula: see text] load with a 2 mA peak-to-peak 1 kHz sinusoid, the circuit draws less than 21 mA from a 9 V source. The minimum operating current of the circuit is less than 12 mA. Voltage compliance is ± 60 V with just 1.02 mA drawn by the high voltage current drive circuitry. The circuit was implemented as a compact 46 mm × 21 mm two-layer PCB highlighting its potential for use in a body-worn device. No design to the best of our knowledge presents comparably low quiescent power with such high voltage compliance. This makes the design uniquely appropriate for low-power transcutaneous current stimulation in wearable applications. Further development of driving and instrumentation circuitry is recommended.

PIC simulation of the vacuum power flow for a 5 terawatt, 5 MV, 1 MA pulsed power system

NASA Astrophysics Data System (ADS)

Liu, Laqun; Zou, Wenkang; Liu, Dagang; Guo, Fan; Wang, Huihui; Chen, Lin

2018-03-01

In this paper, a 5 Terawatt, 5 MV, 1 MA pulsed power system based on vacuum magnetic insulation is simulated by the particle-in-cell (PIC) simulation method. The system consists of 50 100-kV linear transformer drive (LTD) cavities in series, using magnetically insulated induction voltage adder (MIVA) technology for pulsed power addition and transmission. The pulsed power formation and the vacuum power flow are simulated when the system works in self-limited flow and load-limited flow. When the pulsed power system isn't connected to the load, the downstream magnetically insulated transmission line (MITL) works in the self-limited flow, the maximum of output current is 1.14 MA and the amplitude of voltage is 4.63 MV. The ratio of the electron current to the total current is 67.5%, when the output current reached the peak value. When the impedance of the load is 3.0 Ω, the downstream MITL works in the self-limited flow, the maximums of output current and the amplitude of voltage are 1.28 MA and 3.96 MV, and the ratio of the electron current to the total current is 11.7% when the output current reached the peak value. In addition, when the switches are triggered in synchronism with the passage of the pulse power flow, it effectively reduces the rise time of the pulse current.

Non-aqueous aluminium-air battery based on ionic liquid electrolyte

NASA Astrophysics Data System (ADS)

Revel, Renaud; Audichon, Thomas; Gonzalez, Serge

2014-12-01

A promising metal-air secondary battery based on aluminium-oxygen couple is described. In this paper, we observed that an aluminium-air battery employing EMImCl, AlCl3 room temperature ionic liquid (RTIL) as electrolyte and aluminium as negative electrode, has an exceptional reduced self-discharged rate. Due to its new and innovative type of electrolyte, this aluminium-air battery can support relatively high current densities (up to 0.6 mA cm-2) and an average voltage of 0.6-0.8 V. Such batteries may find immediate applications, as they can provide an internal, built-in autonomous and self-sustained energy source.

Compensation for z-directional non-uniformity of a monopole antenna at 7T MRI

NASA Astrophysics Data System (ADS)

Kim, Nambeom; Woo, Myung-Kyun; Kang, Chang-Ki

2016-06-01

The research was conducted to find ways to compensate for z-directional non-uniformity at a monopole antenna array (MA) coil by using a tilted optimized non-saturating excitation (TONE) pulse and to evaluate the feasibility of using the MA coil with the TONE pulse for anatomical and angiographic imaging. The sensitivity of a MA coil along the z-direction was measured by using an actual flip angle imaging pulse sequence with an oil phantom to evaluate the flip angle distributions of the MA coil for 7T magnetic resonance imaging (MRI). The effects on the z-directional uniformity were examined by using slow and fast TONE pulses, i.e., TONE SLOW and TONE FAST. T1- and T2* -weighted images of the human brain were also examined. The z-directional profiles of the TONE pulses were analyzed by using the average signal intensity throughout the brain. The effect of the TONE pulses on cerebral vessels was further examined by analyzing maximal intensity projections of T1-weighted images. With increasing the applied flip angles, the sensitivity slope slightly increased (0.044 per degree). For the MA coil, the TONE SLOWpulse yielded a compensated profile along the z-direction while the TONE HIGH pulse, which has a flat excitation profile along the z-direction, exhibited a tilted signal intensity toward the coil end, clearly indicating an intrinsic property of the MA coil. Similar to the phantom study, human brain images revealed z-directional symmetry around the peak value for the averaged signal intensity of the TONE SLOW pulse while the TONE HIGH pulse exhibited a tilted signal intensity toward the coil end. In vascular system imaging, the MA coil also clearly demonstrated a beneficial effect on the cerebral vessels, either with or without the TONE pulses. This study demonstrates that TONE pulses could compensate for the intrinsic z-directional non-uniformity of MA coils that exhibit strong uniformity in the x-y plane. Furthermore, tilted pulses, such as TONE pulses, were utilized for visualizing small vessels. Appropriately combining MA coils and TONE pulses could help advance micro-vessel visualization.

Characterization of neutron emission from mega-ampere deuterium gas puff Z-pinch at microsecond implosion times

NASA Astrophysics Data System (ADS)

Klir, D.; Shishlov, A. V.; Kokshenev, V. A.; Kubes, P.; Labetsky, A. Yu; Rezac, K.; Cikhardt, J.; Fursov, F. I.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Ratakhin, N. A.; Sila, O.; Stodulka, J.

2013-08-01

Experiments with deuterium (D2) triple shell gas puffs were carried out on the GIT-12 generator at a 3 MA current level and microsecond implosion times. The outer, middle and inner nozzle diameters were 160 mm, 80 mm and 30 mm, respectively. The influence of the mass of deuterium shells on neutron emission times, neutron yields and neutron energy spectra was studied. The injected linear mass of deuterium varied between 50 and 255 µg cm-1. Gas puffs imploded onto the axis before the peak of generator current at 700-1100 ns. Most of the neutrons were emitted during the second neutron pulse after the development of instabilities. Despite higher currents, heavier gas puffs produced lower neutron yields. Optimal mass and a short time delay between the valve opening and the generator triggering were more important than the better coincidence of stagnation with peak current. The peak neutron yield from D(d, n)3He reactions reached 3 × 1011 at 2.8 MA current, 90 µg cm-1 injected linear mass and 37 mm anode-cathode gap. In the case of lower mass shots, a large number of 10 MeV neutrons were produced either by secondary DT reactions or by DD reactions of deuterons with energies above 7 MeV. The average neutron yield ratio Y>10 MeV/Y2.5 MeV reached (6 ± 3) × 10-4. Such a result can be explained by a power law distribution for deuterons as \\rmd N_d/\\rmd E_d\\propto E_d^{-3} . The optimization of a D2 gas puff Z-pinch and similarities to a plasma focus and its drive parameter are described.

Electrode position markedly affects knee torque in tetanic, stimulated contractions.

PubMed

Vieira, Taian M; Potenza, Paolo; Gastaldi, Laura; Botter, Alberto

2016-02-01

The purpose of this study was to investigate how much the distance between stimulation electrodes affects the knee extension torque in tetanic, electrically elicited contractions. Current pulses of progressively larger amplitude, from 0 mA to maximally tolerated intensities, were delivered at 20 pps to the vastus medialis, rectus femoris and vastus lateralis muscles of ten, healthy male subjects. Four inter-electrode distances were tested: 32.5% (L1), 45.0% (L2), 57.5% (L3) and 70% (L4) of the distance between the patella apex and the anterior superior iliac spine. The maximal knee extension torque and the current leading to the maximal torque were measured and compared between electrode configurations. The maximal current tolerated by each participant ranged from 60 to 100 mA and did not depend on the inter-electrode distance. The maximal knee extension torque elicited did not differ between L3 and L4 (P = 0.15) but, for both conditions, knee torque was significantly greater than for L1 and L2 (P < 0.024). On average, the extension torque elicited for L3 and L4 was two to three times greater than that obtained for L1 and L2. The current leading to maximal torque was not as sensitive to inter-electrode distance. Except for L1 current intensity did not change with electrode configuration (P > 0.16). Key results presented here revealed that for a given stimulation intensity, knee extension torque increased dramatically with the distance between electrodes. The distance between electrodes seems therefore to critically affect knee torque, with potential implication for optimising exercise protocols based on electrical stimulation.

Increase of the spontaneous mutation rate in a long-term experiment with Drosophila melanogaster.

PubMed

Avila, Victoria; Chavarrías, David; Sánchez, Enrique; Manrique, Antonio; López-Fanjul, Carlos; García-Dorado, Aurora

2006-05-01

In a previous experiment, the effect of 255 generations of mutation accumulation (MA) on the second chromosome viability of Drosophila melanogaster was studied using 200 full-sib MA1 lines and a large C1 control, both derived from a genetically homogeneous base population. At generation 265, one of those MA1 lines was expanded to start 150 new full-sib MA2 lines and a new C2 large control. After 46 generations, the rate of decline in mean viability in MA2 was approximately 2.5 times that estimated in MA1, while the average degree of dominance of mutations was small and nonsignificant by generation 40 and moderate by generation 80. In parallel, the inbreeding depression rate for viability and the amount of additive variance for two bristle traits in C2 were 2-3 times larger than those in C1. The results are consistent with a mutation rate in the line from which MA2 and C2 were derived about 2.5 times larger than that in MA1. The mean viability of C2 remained roughly similar to that of C1, but the rate of MA2 line extinction increased progressively, leading to mutational collapse, which can be ascribed to accelerated mutation and/or synergy after important deleterious accumulation.

Top-Off Injection and Higher Currents at the Stanford Synchrotron Radiation Lightsource

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

Bauer, Johannes M.; Liu, James C.; Prinz, Alyssa A.

2011-04-05

The Stanford Synchrotron Radiation Lightsource (SSRL) at the SLAC National Accelerator Laboratory is a 234 m circumference storage ring for 3 GeV electrons with its synchrotron radiation serving currently 13 beamlines with about 27 experimental stations. It operated for long time with 100 mA peak current provided by usually three injections per day. In July 2009, the maximum beam current was raised to 200 mA. Over the period from June 2009 to March 2010, Top-Off operation started at every beamline. Top-Off, i.e., the injection of electrons into the storage ring with injection stoppers open, is necessary for SSRL to reachmore » its design current of 500 mA. In the future, the maximal power of the injection current will also soon be raised from currently 1.5 W to 5 W. The Radiation Protection Department at SLAC worked with SSRL on the specifications for the safety systems for operation with Top-Off injection and higher beam currents.« less

An omnipotent Li-ion battery charger with multimode control and polarity reversible techniques

NASA Astrophysics Data System (ADS)

Chen, Jiann-Jong; Ku, Yi-Tsen; Yang, Hong-Yi; Hwang, Yuh-Shyan; Yu, Cheng-Chieh

2016-07-01

The omnipotent Li-ion battery charger with multimode control and polarity reversible techniques is presented in this article. The proposed chip is fabricated with TSMC 0.35μm 2P4M complementary metal-oxide- semiconductor processes, and the chip area including pads is 1.5 × 1.5 mm2. The structure of the omnipotent charger combines three charging modes and polarity reversible techniques, which adapt to any Li-ion batteries. The three reversible Li-ion battery charging modes, including trickle-current charging, large-current charging and constant-voltage charging, can charge in matching polarities or opposite polarities. The proposed circuit has a maximum charging current of 300 mA and the input voltage of the proposed circuit is set to 4.5 V. The maximum efficiency of the proposed charger is about 91% and its average efficiency is 74.8%. The omnipotent charger can precisely provide the charging current to the battery.

Effects of smoke exposure and other lifestyle factors on pain response to electrical stimulation in women.

PubMed

Wee, J Y; Hopman, W M

2008-01-01

A relationship between smoking and development of pain syndromes has been suggested in the literature. The present study examined associations between smoke exposure and other related variables, and pain response to suprathreshold electrical stimulation. Subjects were prospectively recruited from a population referred to an electrodiagnostic clinic. Information about age, smoke exposure, caffeine and alcohol consumption was obtained, as well as documented objective signs of stress through physical assessment. One investigator applied two standardized 0.1 ms electrical stimulations (50 mA followed by 100 mA) to asymptomatic extremities at the beginning of each electrodiagnostic session, using consistent technique. Subjects used a visual analogue scale to indicate the level of pain felt after each stimulation. Two hundred fifteen women were included. Current smokers and those currently exposed to second-hand smoke had significantly higher pain ratings (P=0.003 for 50 mA, P=0.005 for 100 mA) than those not currently exposed to smoke. Time since exposure was negatively associated with pain ratings. Those with objective signs of stress reported higher levels of pain, which was significant for the 100 mA stimulation (P=0.046). Linear regression modelling indicated that current smoke exposure and alcohol use were associated with higher pain ratings at both 50 mA and 100 mA, while stress was associated with higher pain ratings and older age was associated with lower pain ratings at 100 mA only. Exposure to cigarette smoke is significantly related to higher reported levels of pain experienced in response to electrical stimulation in this study population. Exposure to smoke can add 10 points to the 100-point visual analogue scale compared with subjects without exposure, with alcohol use adding another eight points. Reported pain decreases as length of time since previous exposure to smoke increases.

2 MeV linear accelerator for industrial applications

NASA Astrophysics Data System (ADS)

Smith, Richard R.; Farrell, Sherman R.

1997-02-01

RPC Industries has developed a high average power scanned electron beam linac system for medium energy industrial processing, such as in-line sterilization. The parameters are: electron energy 2 MeV; average beam current 5.0 mA; and scanned width 0.5 meters. The control system features data logging and a Man-Machine Interface system. The accelerator is vertically mounted, the system height above the floor is 3.4 m, and the footprint is 0.9×1.2 meter2. The typical processing cell inside dimensions are 3.0 m by 3.5 m by 4.2 m high with concrete side walls 0.5 m thick above ground level. The equal exit depth dose is 0.73 gm cm-2. Additional topics that will be reported are: throughput, measurements of dose vs depth, dose uniformity across the web, and beam power by calorimeter and magnetic deflection of the beam.

Using (1)(0)Be cosmogenic isotopes to estimate erosion rates and landscape changes during the Plio-Pleistocene in the Cradle of Humankind, South Africa.

PubMed

Dirks, Paul H G M; Placzek, Christa J; Fink, David; Dosseto, Anthony; Roberts, Eric

2016-07-01

Concentrations of cosmogenic (10)Be, measured in quartz from chert and river sediment around the Cradle of Humankind (CoH), are used to determine basin-averaged erosion rates and estimate incision rates for local river valleys. This study focusses on the catchment area that hosts Malapa cave with Australopithecus sediba, in order to compare regional versus localized erosion rates, and better constrain the timing of cave formation and fossil entrapment. Basin-averaged erosion rates for six sub-catchments draining the CoH show a narrow range (3.00 ± 0.28 to 4.15 ± 0.37 m/Mega-annum [Ma]; ±1σ) regardless of catchment size or underlying geology; e.g. the sub-catchment with Malapa Cave (3 km(2)) underlain by dolomite erodes at the same rate (3.30 ± 0.30 m/Ma) as the upper Skeerpoort River catchment (87 km(2)) underlain by shale, chert and conglomerate (3.23 ± 0.30 m/Ma). Likewise, the Skeerpoort River catchment (147 km(2)) draining the northern CoH erodes at a rate (3.00 ± 0.28 m/Ma) similar to the Bloubank-Crocodile River catchment (627 km(2)) that drains the southern CoH (at 3.62 ± 0.33 to 4.15 ± 0.37 m/Ma). Dolomite- and siliciclastic-dominated catchments erode at similar rates, consistent with physical weathering as the rate controlling process, and a relatively dry climate in more recent times. Erosion resistant chert dykes along the Grootvleispruit River below Malapa yield an incision rate of ∼8 m/Ma at steady-state erosion rates for chert of 0.86 ± 0.54 m/Ma. Results provide better palaeo-depth estimates for Malapa Cave of 7-16 m at the time of deposition of A. sediba. Low basin-averaged erosion rates and concave river profiles indicate that the landscape across the CoH is old, and eroding slowly; i.e. the physical character of the landscape changed little in the last 3-4 Ma, and dolomite was exposed on surface probably well into the Miocene. The apparent absence of early Pliocene- or Miocene-aged cave deposits and fossils in the CoH suggests that caves only started forming from 4 Ma onwards. Therefore, whilst the landscape in the CoH is old, cavities are a relatively young phenomenon, thus controlling the maximum age of fossils that can potentially be preserved in caves in the CoH. Copyright © 2016 Elsevier Ltd. All rights reserved.

Porous nitrogen-doped carbon microspheres as anode materials for lithium ion batteries.

PubMed

Chen, Taiqiang; Pan, Likun; Loh, T A J; Chua, D H C; Yao, Yefeng; Chen, Qun; Li, Dongsheng; Qin, Wei; Sun, Zhuo

2014-10-28

Nitrogen-doped carbon microspheres (NCSs) were fabricated via a simple, fast and energy-saving microwave-assisted method followed by thermal treatment under an ammonia atmosphere. NCSs thermally treated at different temperatures were investigated as anode materials for lithium ion batteries (LIBs). The results show that NCSs treated at 900 °C exhibit a maximum reversible capacity of 816 mA h g(-1) at a current density of 50 mA g(-1) and preserve a capacity of 660 mA h g(-1) after 50 cycles, and even at a high current density of 1000 mA g(-1), a capacity of 255 mA h g(-1) is maintained. The excellent electrochemical performance of NCSs is due to their porous structure and nitrogen-doping. The present NCSs should be promising low-cost anode materials with a high capacity and good cycle stability for LIBs.

Orange a-plane InGaN/GaN light-emitting diodes grown on r-plane sapphire substrates.

PubMed

Seo, Yong Gon; Baik, Kwang Hyeon; Song, Hooyoung; Son, Ji-Su; Oh, Kyunghwan; Hwang, Sung-Min

2011-07-04

We report on orange a-plane light-emitting diodes (LEDs) with InGaN single quantum well (SQW) grown on r-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). The peak wavelength and the full-width at half maximum (FWHM) at a drive current of 20mA were 612.2 nm and 72 nm, respectively. The device demonstrated a blue shift in emission wavelength from 614.6 nm at 10 mA to 607.5 nm at 100 mA, representing a net shift of 7.1 nm over a 90 mA range, which is the longest wavelength compared with reported values in nonpolar LEDs. The polarization ratio values obtained from the orange LED varied between 0.36 and 0.44 from 10 to 100mA and a weak dependence of the polarization ratio on the injection current was observed.

Compensatory Changes in Energy Balance Regulation over One Athletic Season.

PubMed

Silva, Analiza M; Matias, Catarina N; Santos, Diana A; Thomas, Diana; Bosy-Westphal, Anja; MüLLER, Manfred J; Heymsfield, Steven B; Sardinha, LUíS B

2017-06-01

Mechanisms in energy balance (EB) regulation may include compensatory changes in energy intake (EI) and metabolic adaption (MA), but information is unavailable in athletes who often change EB components. We aim to investigate EB regulation compensatory mechanisms over one athletic season. Fifty-seven athletes (39 males/18 females; handball, volleyball, basketball, triathlon, and swimming) were evaluated from the beginning to the competitive phase of the season. Resting and total energy expenditure (REE and TEE, respectively) were assessed by indirect calorimetry and doubly labeled water, respectively, and physical activity energy expenditure was determined as TEE - 0.1(TEE) - REE. Fat mass (FM) and fat-free mass (FFM) were evaluated by dual-energy x-ray absorptiometry and changed body energy stores was determined by 1.0(ΔFFM/Δtime) + 9.5(ΔFM/Δtime). EI was derived as TEE + EB. REE was predicted from baseline FFM, FM, sex, and sports. %MA was calculated as 100(measured REE/predicted REE-1) and MA (kcal) as %MA/100 multiplied by baseline measured REE. Average EI minus average physical activity energy expenditure was computed as a proxy of average energy availability, assuming that a constant nonexercise EE occurred over the season. Body mass increased by 0.8 ± 2.5 kg (P < 0.05), but a large individual variability was found ranging from -6.1 to 5.2 kg. The TEE raise (16.8% ± 11.7%) was compensated by an increase EI change (16.3% ± 12.0%) for the whole group (P < 0.05). MA was found in triathletes, sparing 128 ± 168 kcal·d, and basketball players, dissipating 168 ± 205 kcal·d (P < 0.05). MA was associated (P < 0.05) with EB and energy availability (r = 0.356 and r = 0.0644, respectively). TEE increased over the season without relevant mean changes in weight, suggesting that EI compensation likely occurred. The thrifty or spendthrift phenotypes observed among sports and the demanding workloads these athletes are exposed to highlight the need for sport-specific energy requirements.

Construction of Hierarchical CuO/Cu₂O@NiCo₂S₄ Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes.

PubMed

Zhou, Luoxiao; He, Ying; Jia, Congpu; Pavlinek, Vladimir; Saha, Petr; Cheng, Qilin

2017-09-15

Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu₂O@NiCo₂S₄) core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu₂O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo₂S₄ nanosheets on the surface of CuO/Cu₂O nanowires to form the CuO/Cu₂O@NiCo₂S₄ core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo₂S₄ nanosheets is ~20 nm and the diameter of CuO/Cu₂O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm -2 at 10 mA cm -2 , good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm -2 ) and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm -2 . These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer.

Multislice CT of the head and body routine scans: Are scanning protocols adjusted for paediatric patients?

PubMed Central

Sun, Z; Al Ghamdi, KS; Baroum, IH

2012-01-01

Purpose: To investigate whether the multislice CT scanning protocols of head, chest and abdomen are adjusted according to patient’s age in paediatric patients. Materials and Methods: Multislice CT examination records of paediatric patients undergoing head, chest and abdomen scans from three public hospitals during a one-year period were retrospectively reviewed. Patients were categorised into the following age groups: under 4 years, 5–8 years, 9–12 years and 13–16 years, while the tube current was classified into the following ranges: < 49 mA, 50–99 mA, 100–149 mA, 150–199 mA, > 200 mA and unknown. Results: A total of 4998 patient records, comprising a combination of head, chest and abdomen CT scans, were assessed, with head CT scans representing nearly half of the total scans. Age-based adjusted CT protocols were observed in most of the scans with higher tube current setting being used with increasing age. However, a high tube current (150–199 mA) was still used in younger patients (0–8 years) undergoing head CT scans. In one hospital, CT protocols remained constant across all age groups, indicating potential overexposure to the patients. Conclusion: This analysis shows that paediatric CT scans are adjusted according to the patient’s age in most of the routine CT examinations. This indicates increased awareness regarding radiation risks associated with CT. However, high tube current settings are still used in younger patient groups, thus, optimisation of paediatric CT protocols and implementation of current guidelines, such as age-and weight-based scanning, should be recommended in daily practice. PMID:22970059

Analysis Monthly Import of Palm Oil Products Using Box-Jenkins Model

NASA Astrophysics Data System (ADS)

Ahmad, Nurul F. Y.; Khalid, Kamil; Saifullah Rusiman, Mohd; Ghazali Kamardan, M.; Roslan, Rozaini; Che-Him, Norziha

2018-04-01

The palm oil industry has been an important component of the national economy especially the agriculture sector. The aim of this study is to identify the pattern of import of palm oil products, to model the time series using Box-Jenkins model and to forecast the monthly import of palm oil products. The method approach is included in the statistical test for verifying the equivalence model and statistical measurement of three models, namely Autoregressive (AR) model, Moving Average (MA) model and Autoregressive Moving Average (ARMA) model. The model identification of all product import palm oil is different in which the AR(1) was found to be the best model for product import palm oil while MA(3) was found to be the best model for products import palm kernel oil. For the palm kernel, MA(4) was found to be the best model. The results forecast for the next four months for products import palm oil, palm kernel oil and palm kernel showed the most significant decrease compared to the actual data.

Investigation of electrodes under flow of a submicrosecond current pulse with linear density up to 3 MA/cm

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

Branitskii, A. V.; Grabovskii, E. V.; Dzhangobegov, V. V.

The states of current-carrying elements at the transmission of megaampere current into load are studied. It is determined that the expansion velocity of plasma generated at the outer surface of cylindrical tubes produced of stainless steel, at flowing through them of submicrosecond current pulses with linear density of 3 MA/cm is 5.5 km/s. The evolution of various modes of instability is analyzed.

Mesoporous graphene-like nanobowls as Pt electrocatalyst support for highly active and stable methanol oxidation

NASA Astrophysics Data System (ADS)

Yan, Zaoxue; He, Guoqiang; Jiang, Zhifeng; Wei, Wei; Gao, Lina; Xie, Jimin

2015-06-01

Mesoporous graphene-like nanobowls (GLBs) with high surface area of 1091 m2 g-1, high pore volume of 2.7 cm3 g-1 and average pore diameter of 9.8 nm are synthesized through template method. The GLBs with inherent excellent electrical conductivity and chemical inertia show the properties of well mass transfer, poison resistance and stable loading of smaller Pt particles. Therefore, the Pt/GLB catalyst shows much higher activity and stability than that of commercial Pt/C (TKK) for methanol oxidation reaction (MOR). Therein, the peak current density on Pt/GLB (2075 mA mgPt-1) for MOR is 2.87 times that of commercial Pt/C (723 mA mgPt-1); and the onset potential for the MOR on the former is negatively shifted about 160 mV compared with that on the latter. The catalytic performances of the Pt/GLB are also better than those of the Pt loading on mesoporous amorphous carbon nanobowls (Pt/BLC), indicating promotion effect of graphite on Pt catalytic performance.

42 CFR 423.279 - National average monthly bid amount.

Code of Federal Regulations, 2014 CFR

2014-10-01

... each MA-PD plan described in section 1851(a)(2)(A)(i) of the Act. The calculation does not include bids... section 1876(h) of the Act. (b) Calculation of weighted average. (1) The national average monthly bid... defined in § 422.258(c)(1) of this chapter) and the denominator equal to the total number of Part D...

42 CFR 423.279 - National average monthly bid amount.

Code of Federal Regulations, 2013 CFR

2013-10-01

... each MA-PD plan described in section 1851(a)(2)(A)(i) of the Act. The calculation does not include bids... section 1876(h) of the Act. (b) Calculation of weighted average. (1) The national average monthly bid... defined in § 422.258(c)(1) of this chapter) and the denominator equal to the total number of Part D...

42 CFR 423.279 - National average monthly bid amount.

Code of Federal Regulations, 2012 CFR

2012-10-01

... each MA-PD plan described in section 1851(a)(2)(A)(i) of the Act. The calculation does not include bids... section 1876(h) of the Act. (b) Calculation of weighted average. (1) The national average monthly bid... defined in § 422.258(c)(1) of this chapter) and the denominator equal to the total number of Part D...

Robust Semi-Active Ride Control under Stochastic Excitation

DTIC Science & Technology

2014-01-01

broad classes of time-series models which are of practical importance; the Auto-Regressive (AR) models, the Integrated (I) models, and the Moving...Average (MA) models [12]. Combinations of these models result in autoregressive moving average (ARMA) and autoregressive integrated moving average...Down Up 4) Down Down These four cases can be written in compact form as: (20) Where is the Heaviside

A New Trend-Following Indicator: Using SSA to Design Trading Rules

NASA Astrophysics Data System (ADS)

Leles, Michel Carlo Rodrigues; Mozelli, Leonardo Amaral; Guimarães, Homero Nogueira

Singular Spectrum Analysis (SSA) is a non-parametric approach that can be used to decompose a time-series as trends, oscillations and noise. Trend-following strategies rely on the principle that financial markets move in trends for an extended period of time. Moving Averages (MAs) are the standard indicator to design such strategies. In this study, SSA is used as an alternative method to enhance trend resolution in comparison with the traditional MA. New trading rules using SSA as indicator are proposed. This paper shows that for the Down Jones Industrial Average (DJIA) and Shangai Securities Composite Index (SSCI) time-series the SSA trading rules provided, in general, better results in comparison to MA trading rules.

Morphemic Analysis as Imagined by Developmental Reading Textbooks: A Content Analysis of a Textbook Corpus

ERIC Educational Resources Information Center

Roth, Daniel

2017-01-01

Although vocabulary instruction is a pressing need for postsecondary reading instructors, a minimal amount of current postsecondary scholarship addresses this need, and almost no current scholarship addresses the textbook tradition of morphemic analysis (MA). The present article reviews the literature on MA instruction and argues for teaching MA…

[Bio-electrochemical effect on hydrogenotrophic sulfate reduction stimulated by electrical field in the presence of H2 under atmospheric pressure].

PubMed

Xu, Hui-Wei; Zhang, Xu; Yang, Shan-Shan; Li, Guang-He

2009-07-15

Microbial sulfate reduction rate is limited with H2 as electron donor. In order to improve hydrogenotrophic sulfate reduction under normal atmospheric H2 pressure, a bio-electrochemical system with direct current was designed and performed in this study. Results indicates that sulfate reduction rate (SRR) increases with the augment of current intensity under lower current intensity (I < or = 1.50 mA). When optimum current intensity of 1.50 mA is applied, the SRR is 1.7 to 2.1 times higher than that of the control reactor. The synergistic effect of electrochemistry and microbiology on sulfate reduction varies at different current intensity. Under the condition of I < or = 1.50 mA, the most probable mechanism of SRR increase is that electric or magnetic field stimulates the proliferation of sulfate-reducing bacteria (SRB) and the activity of the enzymes. When I is higher than 1.50 mA, the activity of SRB is inhibited, resulting in lower reduction rate compared with that at lower current. If controlling the cathode potential lower than -0.69 V and H2 partial pressure 1.01 x 10(5) Pa, electro-catalytic sulfate reduction process takes place with H2 as reductant in this bio-electrochemical system. However, the overall reduction rate is still lower than that when I = 1.50 mA is applied, and additionally the energy consumption is much higher. Therefore, electric field of low intensity can enhance hydrogenotrophic sulfate reduction in the presence of H2 under atmospheric pressure.

Niobium flex cable for low temperature high density interconnects

NASA Astrophysics Data System (ADS)

van Weers, H. J.; Kunkel, G.; Lindeman, M. A.; Leeman, M.

2013-05-01

This work describes the fabrication and characterization of a Niobium on polyimide flex cable suitable for sub-Kelvin temperatures. The processing used can be extended to high density interconnects and allows for direct integration with printed circuit boards. Several key parameters such as RRR, Tc, current carrying capability at 4 K and thermal conductivity in the range from 0.15 to 10 K have been measured. The average Tc was found to be 8.9 K, with a minimum of 8.3 K. Several samples allowed for more than 50 mA current at 4 K while remaining in the superconducting state. The thermal conductivity for this flex design is dominated by the polyimide, in our case Pyralin PI-2611, and is in good agreement with published thermal conductivity data for a polyimide called Upilex R. Registered trademark of Ube Industries, Japan.

A real time index of geomagnetic background noise for the MAD (Magnetic Anomaly Detection) frequency band

NASA Astrophysics Data System (ADS)

Bernardi, A.; Fraser-Smith, A. C.; Villard, O. G.

1985-02-01

An index of geomagnetic activity in the upper part of the ultra low frequency (ULF) range (less than 4.55 Hz) has been developed. This index will be referred to as the MA index (magnetic activity index). The MA index is prepared every half hour and is a measure of the strength of the geomagnetic activity in the Pc1-Pc3 pulsation frequency range during that half hour period. Activity in the individual Pc pulsation ranges can also be measured, if desired. The index is calculated from the running average of the full-wave rectified values of the band pass filtered geomagnetic signals and thus it provides a better indication of the magnitude of these band pass filtered magnetic pulsations than does the ap index, for example. Daily variations of the band pass filtered magnetic signals are also better captured by the MA index. To test this system we used analog tape recordings of wide-band geomagnetic signals. The indices for these tapes are presented in the form of plots, together with a comparison with the ap indices of the same time intervals. The MA index shows the daily variation of the geometric signals quite clearly during times when there is strong activity, i.e., when the ap index values are large. Because impulsive signals, such as lightning discharges, tend to be suppressed in the averaging process, the MA index is insensitive to impulsive noise. It is found that the time variation of the MA index is in general markedly different from the variation of the ap index for the same time intervals.

Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada

NASA Astrophysics Data System (ADS)

Rood, Dylan H.; Burbank, Douglas W.; Herman, Scott W.; Bogue, Scott

2011-10-01

We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (˜9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± ΔR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (˜12-20 Ma), 42 ± 11° since Late Miocene (˜8-9 Ma), and 14 ± 10° since Pliocene (˜3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma-1 (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (˜9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates.

High current DC negative ion source for cyclotron.

PubMed

Etoh, H; Onai, M; Aoki, Y; Mitsubori, H; Arakawa, Y; Sakuraba, J; Kato, T; Mitsumoto, T; Hiasa, T; Yajima, S; Shibata, T; Hatayama, A; Okumura, Y

2016-02-01

A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H(-) beam of 10 mA and D(-) beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H(-) beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H(-) current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H(-) production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H(-) current dependence on the arc power.

Establishment of a Taiwan Marine cable hosted observatory (Ma-Cho project)

NASA Astrophysics Data System (ADS)

Lee, C.; Hsu, S.; Shin, T.

2006-12-01

Taiwan is located in a junction corner between the Philippine Sea Plate and Eurasian Plate. Because of the active convergence, numerous earthquakes have occurred in and around Taiwan. On average, there are about two earthquakes greater than magnitude 6 each year and 80% of earthquakes occurred in the offshore area. Because of the subduction of Philippine Sea Plate beneath the western end of the Ryukyu Arc and northern Taiwan, both the tectonics and seismic activity are intensive. The 2004 Sumatra earthquake has induced giant tsunami attacking coastal countries of South Asia. Due to a similar geodynamic context, the Sumatra event has aroused the attention of Taiwan government. Soon, specialists from Taiwan earth scientists and ocean engineers have teamed up to discuss the potential and mitigation of natural hazards from the western end of the Ryukyu subduction zone. The constructing a submarine cable observatory off eastern Taiwan (Ma-Cho project) was suggested. Ma-Cho means a sea goddess who protects people at sea. The purpose of Ma-Cho project has several folds. Firstly, the extension of seismic stations on land to offshore area can increase the resolution of earthquake locating. Secondly, the extension of seismic stations may obtain tens of second before the destructing seismic waves arrive on land or tens of minute before the arrival of giant tsunami, which is helpful for earthquake or tsunami warning. Thirdly, the seafloor scientific station can monitor the active volcanoes in the Okinawa Trough, which is directly adjacent to the Ilan plain in northeastern Taiwan. Fourthly, the seafloor observatory can be used to continuously study the Kurosho current, off eastern Taiwan. The Ma- Cho project has been granted for the first year. From 2007, we will start with a submarine route survey and a construction of the submarine cable land station. The main submarine cable frame and the connection of scientific instruments to cable nodes will be finished in 2009.

Long-term patterns of body mass and stature evolution within the hominin lineage.

PubMed

Will, Manuel; Pablos, Adrián; Stock, Jay T

2017-11-01

Body size is a central determinant of a species' biology and adaptive strategy, but the number of reliable estimates of hominin body mass and stature have been insufficient to determine long-term patterns and subtle interactions in these size components within our lineage. Here, we analyse 254 body mass and 204 stature estimates from a total of 311 hominin specimens dating from 4.4 Ma to the Holocene using multi-level chronological and taxonomic analytical categories. The results demonstrate complex temporal patterns of body size variation with phases of relative stasis intermitted by periods of rapid increases. The observed trajectories could result from punctuated increases at speciation events, but also differential proliferation of large-bodied taxa or the extinction of small-bodied populations. Combined taxonomic and temporal analyses show that in relation to australopithecines, early Homo is characterized by significantly larger average body mass and stature but retains considerable diversity, including small body sizes. Within later Homo , stature and body mass evolution follow different trajectories: average modern stature is maintained from ca 1.6 Ma, while consistently higher body masses are not established until the Middle Pleistocene at ca 0.5-0.4 Ma, likely caused by directional selection related to colonizing higher latitudes. Selection against small-bodied individuals (less than 40 kg; less than 140 cm) after 1.4 Ma is associated with a decrease in relative size variability in later Homo species compared with earlier Homo and australopithecines. The isolated small-bodied individuals of Homo naledi ( ca 0.3 Ma) and Homo floresiensis ( ca 100-60 ka) constitute important exceptions to these general patterns, adding further layers of complexity to the evolution of body size within the genus Homo . At the end of the Late Pleistocene and Holocene, body size in Homo sapiens declines on average, but also extends to lower limits not seen in comparable frequency since early Homo .

Long-term patterns of body mass and stature evolution within the hominin lineage

PubMed Central

Pablos, Adrián; Stock, Jay T.

2017-01-01

Body size is a central determinant of a species' biology and adaptive strategy, but the number of reliable estimates of hominin body mass and stature have been insufficient to determine long-term patterns and subtle interactions in these size components within our lineage. Here, we analyse 254 body mass and 204 stature estimates from a total of 311 hominin specimens dating from 4.4 Ma to the Holocene using multi-level chronological and taxonomic analytical categories. The results demonstrate complex temporal patterns of body size variation with phases of relative stasis intermitted by periods of rapid increases. The observed trajectories could result from punctuated increases at speciation events, but also differential proliferation of large-bodied taxa or the extinction of small-bodied populations. Combined taxonomic and temporal analyses show that in relation to australopithecines, early Homo is characterized by significantly larger average body mass and stature but retains considerable diversity, including small body sizes. Within later Homo, stature and body mass evolution follow different trajectories: average modern stature is maintained from ca 1.6 Ma, while consistently higher body masses are not established until the Middle Pleistocene at ca 0.5–0.4 Ma, likely caused by directional selection related to colonizing higher latitudes. Selection against small-bodied individuals (less than 40 kg; less than 140 cm) after 1.4 Ma is associated with a decrease in relative size variability in later Homo species compared with earlier Homo and australopithecines. The isolated small-bodied individuals of Homo naledi (ca 0.3 Ma) and Homo floresiensis (ca 100–60 ka) constitute important exceptions to these general patterns, adding further layers of complexity to the evolution of body size within the genus Homo. At the end of the Late Pleistocene and Holocene, body size in Homo sapiens declines on average, but also extends to lower limits not seen in comparable frequency since early Homo. PMID:29291118

Thermal Properties of West Siberian Sediments in Application to Basin and Petroleum Systems Modeling

NASA Astrophysics Data System (ADS)

Romushkevich, Raisa; Popov, Evgeny; Popov, Yury; Chekhonin, Evgeny; Myasnikov, Artem; Kazak, Andrey; Belenkaya, Irina; Zagranovskaya, Dzhuliya

2016-04-01

Quality of heat flow and rock thermal property data is the crucial question in basin and petroleum system modeling. A number of significant deviations in thermal conductivity values were observed during our integral geothermal study of West Siberian platform reporting that the corrections should be carried out in basin models. The experimental data including thermal anisotropy and heterogeneity measurements were obtained along of more than 15 000 core samples and about 4 500 core plugs. The measurements were performed in 1993-2015 with the optical scanning technique within the Continental Super-Deep Drilling Program (Russia) for scientific super-deep well Tyumenskaya SG-6, parametric super-deep well Yen-Yakhinskaya, and deep well Yarudeyskaya-38 as well as for 13 oil and gas fields in the West Siberia. Variations of the thermal conductivity tensor components in parallel and perpendicular direction to the layer stratification (assessed for 2D anisotropy model of the rock studied), volumetric heat capacity and thermal anisotropy coefficient values and average values of the thermal properties were the subject of statistical analysis for the uppermost deposits aged by: T3-J2 (200-165 Ma); J2-J3 (165-150 Ma); J3 (150-145 Ma); K1 (145-136 Ma); K1 (136-125 Ma); K1-K2 (125-94 Ma); K2-Pg+Ng+Q (94-0 Ma). Uncertainties caused by deviations of thermal conductivity data from its average values were found to be as high as 45 % leading to unexpected errors in the basin heat flow determinations. Also, the essential spatial-temporal variations in the thermal rock properties in the study area is proposed to be taken into account in thermo-hydrodynamic modeling of hydrocarbon recovery with thermal methods. The research work was done with financial support of the Russian Ministry of Education and Science (unique identification number RFMEFI58114X0008).

A Comparison of Patients Absorption Doses with Bone Deformity Due to the EOS Imaging and Digital Radiology

PubMed Central

Abrisham, Seyed Mohammad J.; Bouzarjomehri, Fathollah; Nafisi-Moghadam, Reza; Sobhan, Mohammad R.; Gadimi, Mahdie; Omidvar, Fereshte

2017-01-01

Background: This study has aimed to measure the patient dose in entire spine radiography by EOS system in comparison with the digital radiography. Methods: EOS stereo-radiography was used for frontal and lateral view spine imaging in 41 patients in a prospective analytical study. A calibrated dose area product (DAP) meter was used for calibration of the DAP in EOS system. The accuracy and precision of the system was confirmed according to the acceptance testing. The same procedure was used for 18 patients referred for lumbar spine digital radiology (overall 36 images). Results: Although radiation fields in the EOS were almost twice of that in digital radiology, and the average peak tube voltage (kVp), current supply to the tube (mA), and the average size and age of the patients referred for EOS imaging were greater than digital radiology, however, the average DAP in EOS was 1/5 of that in digital radiology system. Also, the average dose in the EOS was about 1/20 of that in digital radiology. Conclusion: The patient dose in EOS imaging system was lower in comparison with digital radiology (1/20). PMID:28656161

A Comparison of Patients Absorption Doses with Bone Deformity Due to the EOS Imaging and Digital Radiology.

PubMed

Abrisham, Seyed Mohammad J; Bouzarjomehri, Fathollah; Nafisi-Moghadam, Reza; Sobhan, Mohammad R; Gadimi, Mahdie; Omidvar, Fereshte

2017-05-01

This study has aimed to measure the patient dose in entire spine radiography by EOS system in comparison with the digital radiography. EOS stereo-radiography was used for frontal and lateral view spine imaging in 41 patients in a prospective analytical study. A calibrated dose area product (DAP) meter was used for calibration of the DAP in EOS system. The accuracy and precision of the system was confirmed according to the acceptance testing. The same procedure was used for 18 patients referred for lumbar spine digital radiology (overall 36 images). Although radiation fields in the EOS were almost twice of that in digital radiology, and the average peak tube voltage (kV p ), current supply to the tube (mA), and the average size and age of the patients referred for EOS imaging were greater than digital radiology, however, the average DAP in EOS was 1/5 of that in digital radiology system. Also, the average dose in the EOS was about 1/20 of that in digital radiology. The patient dose in EOS imaging system was lower in comparison with digital radiology (1/20).

Polynomials to model the growth of young bulls in performance tests.

PubMed

Scalez, D C B; Fragomeni, B O; Passafaro, T L; Pereira, I G; Toral, F L B

2014-03-01

The use of polynomial functions to describe the average growth trajectory and covariance functions of Nellore and MA (21/32 Charolais+11/32 Nellore) young bulls in performance tests was studied. The average growth trajectories and additive genetic and permanent environmental covariance functions were fit with Legendre (linear through quintic) and quadratic B-spline (with two to four intervals) polynomials. In general, the Legendre and quadratic B-spline models that included more covariance parameters provided a better fit with the data. When comparing models with the same number of parameters, the quadratic B-spline provided a better fit than the Legendre polynomials. The quadratic B-spline with four intervals provided the best fit for the Nellore and MA groups. The fitting of random regression models with different types of polynomials (Legendre polynomials or B-spline) affected neither the genetic parameters estimates nor the ranking of the Nellore young bulls. However, fitting different type of polynomials affected the genetic parameters estimates and the ranking of the MA young bulls. Parsimonious Legendre or quadratic B-spline models could be used for genetic evaluation of body weight of Nellore young bulls in performance tests, whereas these parsimonious models were less efficient for animals of the MA genetic group owing to limited data at the extreme ages.

Predicting apricot phenology using meteorological data.

PubMed

Ruml, Mirjana; Milatović, Dragan; Vulić, Todor; Vuković, Ana

2011-09-01

The main objective of this study was to develop feasible, easy to apply models for early prediction of full flowering (FF) and maturing (MA) in apricot (Prunus armeniaca L.). Phenological data for 20 apricot cultivars grown in the Belgrade region were modeled against averages of daily temperature records over ten seasons for FF and eight seasons for MA. A much stronger correlation was found between the phenological timing and temperature at the very beginning than at the end of phenophases. Also, the length of developmental periods were better correlated to daily maximum than to daily minimum and mean air temperatures. Using prediction models based on daily maximum temperatures averaged over 30-, 45- and 60-day periods, starting from 1 January for FF prediction and from the date of FF for MA prediction, the onset of examined phenophases in apricot cultivars could be predicted from a few weeks to up to 2 months ahead with acceptable accuracy. The mean absolute differences between the observations and cross-validated predictions obtained by 30-, 45- and 60-day models were 8.6, 6.9 and 5.7 days for FF and 6.1, 3.6 and 2.8 days for MA, respectively. The validity of the results was confirmed using an independent data set for the year 2009.

Predicting apricot phenology using meteorological data

NASA Astrophysics Data System (ADS)

Ruml, Mirjana; Milatović, Dragan; Vulić, Todor; Vuković, Ana

2011-09-01

The main objective of this study was to develop feasible, easy to apply models for early prediction of full flowering (FF) and maturing (MA) in apricot ( Prunus armeniaca L.). Phenological data for 20 apricot cultivars grown in the Belgrade region were modeled against averages of daily temperature records over ten seasons for FF and eight seasons for MA. A much stronger correlation was found between the phenological timing and temperature at the very beginning than at the end of phenophases. Also, the length of developmental periods were better correlated to daily maximum than to daily minimum and mean air temperatures. Using prediction models based on daily maximum temperatures averaged over 30-, 45- and 60-day periods, starting from 1 January for FF prediction and from the date of FF for MA prediction, the onset of examined phenophases in apricot cultivars could be predicted from a few weeks to up to 2 months ahead with acceptable accuracy. The mean absolute differences between the observations and cross-validated predictions obtained by 30-, 45- and 60-day models were 8.6, 6.9 and 5.7 days for FF and 6.1, 3.6 and 2.8 days for MA, respectively. The validity of the results was confirmed using an independent data set for the year 2009.

MaPLE: A MapReduce Pipeline for Lattice-based Evaluation and Its Application to SNOMED CT

PubMed Central

Zhang, Guo-Qiang; Zhu, Wei; Sun, Mengmeng; Tao, Shiqiang; Bodenreider, Olivier; Cui, Licong

2015-01-01

Non-lattice fragments are often indicative of structural anomalies in ontological systems and, as such, represent possible areas of focus for subsequent quality assurance work. However, extracting the non-lattice fragments in large ontological systems is computationally expensive if not prohibitive, using a traditional sequential approach. In this paper we present a general MapReduce pipeline, called MaPLE (MapReduce Pipeline for Lattice-based Evaluation), for extracting non-lattice fragments in large partially ordered sets and demonstrate its applicability in ontology quality assurance. Using MaPLE in a 30-node Hadoop local cloud, we systematically extracted non-lattice fragments in 8 SNOMED CT versions from 2009 to 2014 (each containing over 300k concepts), with an average total computing time of less than 3 hours per version. With dramatically reduced time, MaPLE makes it feasible not only to perform exhaustive structural analysis of large ontological hierarchies, but also to systematically track structural changes between versions. Our change analysis showed that the average change rates on the non-lattice pairs are up to 38.6 times higher than the change rates of the background structure (concept nodes). This demonstrates that fragments around non-lattice pairs exhibit significantly higher rates of change in the process of ontological evolution. PMID:25705725

Eruption history of the Tharsis shield volcanoes, Mars

NASA Technical Reports Server (NTRS)

Plescia, J. B.

1993-01-01

The Tharsis Montes volcanoes and Olympus Mons are giant shield volcanoes. Although estimates of their average surface age have been made using crater counts, the length of time required to build the shields has not been considered. Crater counts for the volcanoes indicate the constructs are young; average ages are Amazonian to Hesperian. In relative terms; Arsia Mons is the oldest, Pavonis Mons intermediate, and Ascreaus Mons the youngest of the Tharsis Montes shield; Olympus Mons is the youngest of the group. Depending upon the calibration, absolute ages range from 730 Ma to 3100 Ma for Arsia Mons and 25 Ma to 100 Ma for Olympus Mons. These absolute chronologies are highly model dependent, and indicate only the time surficial volcanism ceased, not the time over which the volcano was built. The problem of estimating the time necessary to build the volcanoes can be attacked in two ways. First, eruption rates from terrestrial and extraterrestrial examples can be used to calculate the required period of time to build the shields. Second, some relation of eruptive activity between the volcanoes can be assumed, such as they all began at a speficic time or they were active sequentially, and calculate the eruptive rate. Volumes of the shield volcanoes were derived from topographic/volume data.

MaPLE: A MapReduce Pipeline for Lattice-based Evaluation and Its Application to SNOMED CT.

PubMed

Zhang, Guo-Qiang; Zhu, Wei; Sun, Mengmeng; Tao, Shiqiang; Bodenreider, Olivier; Cui, Licong

2014-10-01

Non-lattice fragments are often indicative of structural anomalies in ontological systems and, as such, represent possible areas of focus for subsequent quality assurance work. However, extracting the non-lattice fragments in large ontological systems is computationally expensive if not prohibitive, using a traditional sequential approach. In this paper we present a general MapReduce pipeline, called MaPLE (MapReduce Pipeline for Lattice-based Evaluation), for extracting non-lattice fragments in large partially ordered sets and demonstrate its applicability in ontology quality assurance. Using MaPLE in a 30-node Hadoop local cloud, we systematically extracted non-lattice fragments in 8 SNOMED CT versions from 2009 to 2014 (each containing over 300k concepts), with an average total computing time of less than 3 hours per version. With dramatically reduced time, MaPLE makes it feasible not only to perform exhaustive structural analysis of large ontological hierarchies, but also to systematically track structural changes between versions. Our change analysis showed that the average change rates on the non-lattice pairs are up to 38.6 times higher than the change rates of the background structure (concept nodes). This demonstrates that fragments around non-lattice pairs exhibit significantly higher rates of change in the process of ontological evolution.

Occurrence of Quaternary turbidite deposits in the central South China Sea: Response to global sea-level changes

NASA Astrophysics Data System (ADS)

Liu, Z.; Zhang, X.; Christophe, C.; Peleo-Alampay, A.; Guballa, J. D. S.; Li, P.; Liu, C.

2016-12-01

Terrigenous turbidite layers frequently occur at the upper 150-m-thick sedimentary sequence of Hole U1431D (15º22.54'N, 117 º00.00'E, 4240.5 m water depth), International Ocean Discovery Program (IODP) Expedition 349, near the relict spreading ridge in the central South China Sea. This study implies visual statistics combined with grain size, clay mineralogy, and Nd-Sr isotope analyses to reconstruct the occurrence of these turbidite layers. The age-model of combined calcareous nannofossils, planktonic foraminifers, and paleomagnetism suggests that the sedimentary sequence spans the entire Quaternary with an age of 2.6 Ma at the depth of 150 mcd below the seafloor. Our results show that the turbidite deposits are dominated by silt with sandy silt and silty clay, poorly sorted, and grading upward with erosion base. The occurrence of turbidite layers are highly frequent with about 3.06 layers per meter and an average thickness of 14.64 cm per layer above 96 mcd ( 1.6 Ma), while the lower part turbudite layers are less frequently developed with 1.16 layers per meter and an average thickness of 5.67 cm. Provenance analysis indicates that Taiwan, about 900 km northward to the studied site, is the major source for these terrigenous sediments, implying the long run-out turbidity current activity over the very low-gradient deep-sea plain of the South China Sea. The frequency of the turbidite layer occurrence is well correlated to the Quaternary global sea-level change history, with the high frequency occurred during the lower sea-level stands. Our study suggests that the glacial-interglacial-scale sea-level change has controlled terrigenous sediment input from Taiwan and the northern shelf of the South China Sea during the Quaternary. The increase of turbidite layer frequency since 1.6 Ma in the central South China Sea could be triggered by the enlarged amplitude of sea-level change.

Study of Lithium Silicide Nanoparticles as Anode Materials for Advanced Lithium Ion Batteries.

PubMed

Li, Xuemin; Kersey-Bronec, Faith E; Ke, John; Cloud, Jacqueline E; Wang, Yonglong; Ngo, Chilan; Pylypenko, Svitlana; Yang, Yongan

2017-05-17

The development of high-performance silicon anodes for the next generation of lithium ion batteries (LIBs) evokes increasing interest in studying its lithiated counterpart-lithium silicide (Li x Si). In this paper we report a systematic study of three thermodynamically stable phases of Li x Si (x = 4.4, 3.75, and 2.33) plus nitride-protected Li 4.4 Si, which are synthesized via the high-energy ball-milling technique. All three Li x Si phases show improved performance over that of unmodified Si, where Li 4.4 Si demonstrates optimum performance with a discharging capacity of 3306 (mA h)/g initially and maintains above 2100 (mA h)/g for over 30 cycles and above 1200 (mA h)/g for over 60 cycles at the current density of 358 mA/g of Si. A fundamental question studied is whether different electrochemical paradigms, that is, delithiation first or lithiation first, influence the electrode performance. No significant difference in electrode performance is observed. When a nitride layer (Li x N y Si z ) is created on the surface of Li 4.4 Si, the cyclability is improved to retain the capacity above 1200 (mA h)/g for more than 80 cycles. By increasing the nitridation extent, the capacity retention is improved significantly from the average decrease of 1.06% per cycle to 0.15% per cycle, while the initial discharge capacity decreases due to the inactivity of Si in the Li x N y Si z layer. Moreover, the Coulombic efficiencies of all Li x Si-based electrodes in the first cycle are significantly higher than that of a Si electrode (∼90% vs 40-70%).

Increase of the Spontaneous Mutation Rate in a Long-Term Experiment With Drosophila melanogaster

PubMed Central

Ávila, Victoria; Chavarrías, David; Sánchez, Enrique; Manrique, Antonio; López-Fanjul, Carlos; García-Dorado, Aurora

2006-01-01

In a previous experiment, the effect of 255 generations of mutation accumulation (MA) on the second chromosome viability of Drosophila melanogaster was studied using 200 full-sib MA1 lines and a large C1 control, both derived from a genetically homogeneous base population. At generation 265, one of those MA1 lines was expanded to start 150 new full-sib MA2 lines and a new C2 large control. After 46 generations, the rate of decline in mean viability in MA2 was ∼2.5 times that estimated in MA1, while the average degree of dominance of mutations was small and nonsignificant by generation 40 and moderate by generation 80. In parallel, the inbreeding depression rate for viability and the amount of additive variance for two bristle traits in C2 were 2–3 times larger than those in C1. The results are consistent with a mutation rate in the line from which MA2 and C2 were derived about 2.5 times larger than that in MA1. The mean viability of C2 remained roughly similar to that of C1, but the rate of MA2 line extinction increased progressively, leading to mutational collapse, which can be ascribed to accelerated mutation and/or synergy after important deleterious accumulation. PMID:16547099

Understanding Variations in Medicare Consumer Assessment of Health Care Providers and Systems Scores: California as an Example

PubMed Central

Farley, Donna O; Elliott, Marc N; Haviland, Amelia M; Slaughter, Mary Ellen; Heller, Amy

2011-01-01

Objective To understand reasons why California has lower Consumer Assessment of Healthcare Providers and Systems (CAHPS) scores than the rest of the country, including differing patterns of CAHPS scores between Medicare Advantage (MA) and fee-for-service, effects of additional demographic characteristics of beneficiaries, and variation across MA plans within California. Study Design/Data Collection Using 2008 CAHPS survey data for fee-for-service Medicare beneficiaries and MA members, we compared mean case mix adjusted Medicare CAHPS scores for California and the remainder of the nation. Principal Findings California fee-for-service Medicare had lower scores than non-California fee-for-service on 11 of 14 CAHPS measures; California MA had lower scores only for physician services measures and higher scores for other measures. Adding race/ethnicity and urbanity to risk adjustment improved California standing for all measures in both MA and fee-for-service. Within the MA plans, one large plan accounted for the positive performance in California MA; other California plans performed below national averages. Conclusions This study shows that the mix of fee-for-service and MA enrollees, demographic characteristics of populations, and plan-specific factors can all play a role in observed regional variations. Anticipating value-based payments, further study of successful MA plans could generate lessons for enhancing patient experience for the Medicare population. PMID:21644970

Road Salt Transport at Two Municipal Wellfields in Wilmington, MA

EPA Science Inventory

Chloride concentrations in raw water at the Browns Crossing and Barrows Wellfields in Wilmington, Massachusetts have increased from an average of 6 mg/l in 1961 to 242 mg/l today. Average sodium concentrations since 2009 are six to seven times the state’s drinking water guideline...

Factors associated with feed intake of Angus steers

USDA-ARS?s Scientific Manuscript database

Estimates of variance components were obtained from 475 records of average (AFI) and residual feed intake (RFI). Covariates in various (8) models included average daily gain (G), age (A) and weight (W) on test, and slaughter (S) and ultrasound (U) carcass measures (fat thickness, ribeye area and ma...

Geologic history of the Blackbird Co-Cu district in the Lemhi subbasin of the Belt-Purcell Basin

USGS Publications Warehouse

Bookstrom, Arthur A.; Box, Stephen E.; Cossette, Pamela M.; Frost, Thomas P.; Gillerman, Virginia; King, George; Zirakparvar, N. Alex

2016-01-01

The Blackbird cobalt-copper (Co-Cu) district in the Salmon River Mountains of east-central Idaho occupies the central part of the Idaho cobalt belt—a northwest-elongate, 55-km-long belt of Co-Cu occurrences, hosted in grayish siliciclastic metasedimentary strata of the Lemhi subbasin (of the Mesoproterozoic Belt-Purcell Basin). The Blackbird district contains at least eight stratabound ore zones and many discordant lodes, mostly in the upper part of the banded siltite unit of the Apple Creek Formation of Yellow Lake, which generally consists of interbedded siltite and argillite. In the Blackbird mine area, argillite beds in six stratigraphic intervals are altered to biotitite containing over 75 vol% of greenish hydrothermal biotite, which is preferentially mineralized.Past production and currently estimated resources of the Blackbird district total ~17 Mt of ore, averaging 0.74% Co, 1.4% Cu, and 1.0 ppm Au (not including downdip projections of ore zones that are open downward). A compilation of relative-age relationships and isotopic age determinations indicates that most cobalt mineralization occurred in Mesoproterozoic time, whereas most copper mineralization occurred in Cretaceous time.Mesoproterozoic cobaltite mineralization accompanied and followed dynamothermal metamorphism and bimodal plutonism during the Middle Mesoproterozoic East Kootenay orogeny (ca. 1379–1325 Ma), and also accompanied Grenvilleage (Late Mesoproterozoic) thermal metamorphism (ca. 1200–1000 Ma). Stratabound cobaltite-biotite ore zones typically contain cobaltite1 in a matrix of biotitite ± tourmaline ± minor xenotime (ca. 1370–1320 Ma) ± minor chalcopyrite ± sparse allanite ± sparse microscopic native gold in cobaltite. Such cobaltite-biotite lodes are locally folded into tight F2 folds with axial-planar S2 cleavage and schistosity. Discordant replacement-style lodes of cobaltite2-biotite ore ± xenotime2 (ca. 1320–1270 Ma) commonly follow S2fractures and fabrics. Discordant quartz-biotite and quartz-tourmaline breccias, and veins contain cobaltite3 ± xenotime3 (ca. 1058–990 Ma).Mesoproterozoic cobaltite deposition was followed by: (1) within-plate plutonism (530–485 Ma) and emplacement of mafic dikes (which cut cobaltite lodes but are cut by quartz-Fe-Cu-sulfide veins); (2) garnet-grade metamorphism (ca. 151–93 Ma); (3) Fe-Cu-sulfide mineralization (ca. 110–92 Ma); and (4) minor quartz ± Au-Ag ± Bi mineralization (ca. 92–83 Ma).Cretaceous Fe-Cu-sulfide vein, breccia, and replacement-style deposits contain various combinations of chalcopyrite ± pyrrhotite ± pyrite ± cobaltian arsenopyrite (not cobaltite) ± arsenopyrite ± quartz ± siderite ± monazite (ca. 144–88 Ma but mostly 110–92 Ma) ± xenotime (104–93 Ma). Highly radiogenic Pb (in these sulfides) and Sr (in siderite) indicate that these elements resided in Mesoproterozoic source rocks until they were mobilized after ca. 100 Ma. Fe-Cu-sulfide veins, breccias, and replacement deposits appear relatively undeformed and generally lack metamorphic fabrics.Composite Co-Cu-Au ore contains early cobaltite-biotite lodes, cut by Fe-Cu-sulfide veins and breccias, or overprinted by Fe-Cu-sulfide replacement-style deposits, and locally cut by quartz veinlets ± Au-Ag ± Bi minerals.

DMS-MaPseq for genome-wide or targeted RNA structure probing in vivo

PubMed Central

Zubradt, Meghan; Gupta, Paromita; Persad, Sitara; Lambowitz, Alan M.; Weissman, Jonathan S.; Rouskin, Silvi

2017-01-01

Coupling structure-specific in vivo chemical modification to next-generation sequencing is transforming RNA secondary structural studies in living cells. The dominant strategy for detecting in vivo chemical modifications uses reverse transcriptase truncation products, which introduces biases and necessitates population-average assessments of RNA structure. Here we present dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq), which encodes DMS modifications as mismatches using a thermostable group II intron reverse transcriptase (TGIRT). DMS-MaPseq yields a high signal-to-noise ratio, can report multiple structural features per molecule, and allows both genome-wide studies and focused in vivo investigations of even low abundance RNAs. We apply DMS-MaPseq for the first analysis of RNA structure within an animal tissue and to identify a functional structure involved in non-canonical translation initiation. Additionally, we use DMS-MaPseq to compare the in vivo structure of pre-mRNAs to their mature isoforms. These applications illustrate DMS-MaPseq’s capacity to dramatically expand in vivo analysis of RNA structure. PMID:27819661

Distributed Attentional Deficits in Chronic Methamphetamine Abusers: Evidence from the Attentional Network Task (ANT)

ERIC Educational Resources Information Center

Salo, Ruth; Gabay, Shai; Fassbender, Catherine; Henik, Avishai

2011-01-01

Objective: The goal of the present study was to examine distributed attentional functions in long-term but currently abstinent methamphetamine (MA) abusers using a task that measures attentional alertness, orienting, and conflict resolution. Methods: Thirty currently abstinent MA abusers (1 month-5 years) and 22 healthy non-substance using adults…

A new Late Cretaceous paleomagnetic pole from the Adel Mountains, west central Montana

NASA Astrophysics Data System (ADS)

Gunderson, Jay A.; Sheriff, Steven D.

1991-01-01

North America's apparent polar wander path has been poorly defined between the mid-Cretaceous and Paleocene reference pole positions. Existing data allowed 13° of apparent polar motion over about 22 m.y. (87-65 Ma) roughly coinciding with the beginning of Laramide deformation (˜80 Ma). We report on a paleomagnetic study of the Adel Mountain Volcanic rocks to refine the North American apparent polar wander path for this interval. The shonkinite rocks of the Adel Mountain Volcanic field are on the eastern edge of the Cretaceous-Paleocene fold and thrust belt; some of these structures disturb the western edge of the volcanic pile. We obtained two new K-Ar dates from the Adel rocks. One date, on biotite ( from a shonkinite dike that crosscuts most of the volcanic rocks, is 71.2±2.7 Ma. The other, a whole rock date from a flow deep in the volcanic pile, is 81.1±3.5 Ma. We collected six to nine paleomagnetic samples from each of 34 sites in roadcuts and natural outcrops of flows, dikes, and laccoliths. Positive fold and conglomerate tests, along with alternating field and thermal demagnetization, indicate that our characteristic remanent directions are primary magnetizations acquired before Late Cretaceous to Paleocene thrust belt deformation. Averaging the virtual geomagnetic poles from 26 reliable sites, all of normal polarity, yields a paleopole at 82.2°N, 209.9°E (α95 = 6.80°, k = 18.38). This pole is concordant with the Paleocene reference pole (82.0°N, 170.2°E, α95 = 3.5°, k = 18.6 (Diehl et al., 1983)) and is 11.6° from the Globerman and Irving (1988) mid-Cretaceous pole at 71°N, 196°E. The youngest information in the Cretaceous stillstand pole is from the Niobrara Formation (Shive and Frerichs, 1974) at about 85-89 Ma. If we take the average age of the Adel Mountain Volcanics to be 76 Ma, then ˜12° of apparent polar motion occurred between 87 Ma and 76 Ma. Thus, rapid apparent polar motion correlates well with the onset of Laramide deformation.

Fabrication and Magnetic Properties of Co₂MnAl Heusler Alloys by Mechanical Alloying.

PubMed

Lee, Chung-Hyo

2018-02-01

We have applied mechanical alloying (MA) to produce nanocrystalline Co2MnAl Heusler alloys using a mixture of elemental Co50Mn25Al25 powders. An optimal milling and heat treatment conditions to obtain a Co2MnAl Heusler phase with fine microstructure were investigated by X-ray diffraction, differential scanning calorimeter and vibrating sample magnetometer measurements. α-(Co, Mn, Al) FCC phases coupled with amorphous phase are obtained after 3 hours of MA without any evidence for the formation of Co2MnAl alloys. On the other hand, a Co2MnAl Heusler alloys can be obtained by the heat treatment of all MA samples up to 650 °C. X-ray diffraction result shows that the average grain size of Co2MnAl Heusler alloys prepared by MA for 5 h and heat treatment is in the range of 95 nm. The saturation magnetization of MA powders decreases with MA time due to the magnetic dilution by alloying with nonmagnetic Mn and Al elements. The magnetic hardening due to the reduction of the grain size with ball milling is also observed. However, the saturation magnetization of MA powders after heat treatment increases with MA time and reaches to a maximum value of 105 emu/g after 5 h of MA. It can be also seen that the coercivity of 5 h MA sample annealed at 650 °C is fairly low value of 25 Oe.

In-Situ Crafting of ZnFe₂O₄ Nanoparticles Impregnated within Continuous Carbon Network as Advanced Anode Materials.

PubMed

Jiang, Beibei; Han, Cuiping; Li, Bo; He, Yanjie; Lin, Zhiqun

2016-02-23

The ability to create a synergistic effect of nanostructure engineering and its hybridization with conductive carbonaceous material is highly desirable for attaining high-performance lithium ion batteries (LIBs). Herein, we judiciously crafted ZnFe2O4/carbon nanocomposites composed of ZnFe2O4 nanoparticles with an average size of 16 ± 5 nm encapsulated within the continuous carbon network as anode materials for LIBs. Such intriguing nanocomposites were yielded in situ via the pyrolysis-induced carbonization of polystyrene@poly(acrylic acid) (PS@PAA) core@shell nanospheres in conjunction with the formation of ZnFe2O4 nanoparticles through the thermal decomposition of ZnFe2O4 precursors incorporated within the PS@PAA nanospheres. By systematically varying the ZnFe2O4 content in the ZnFe2O4/carbon nanocomposites, the nanocomposite containing 79.3 wt % ZnFe2O4 was found to exhibit an excellent rate performance with high capacities of 1238, 1198, 1136, 1052, 926, and 521 mAh g(-1) at specific currents of 100, 200, 500, 1000, 2000, and 5000 mA g(-1), respectively. Moreover, cycling performance of the ZnFe2O4/carbon nanocomposite with 79.3 wt % ZnFe2O4 at specific currents of 200 mA g(-1) delivered an outstanding prolonged cycling stability for several hundred cycles.

Experimental demonstration of monolithically integrated 16 channel DFB laser array fabricated by nanoimprint lithography with AWG multiplexer and SOA for WDM-PON application

NASA Astrophysics Data System (ADS)

Zhao, Jianyi; Chen, Xin; Zhou, Ning; Huang, Xiaodong; Cao, Mingde; Wang, Lei; Liu, Wen

2015-03-01

A 16-channel monolithically integrated distributed feedback (DFB) laser array with arrayed waveguide gratings (AWGs) multiplexer and semiconductor optical amplifier (SOA) has been fabricated using nanoimprint technology. Selective lasing wavelength with 200 GHz frequency space has been obtained. The typical threshold current is between 20 mA and 30 mA. The output power is higher than 1 mW with 350 mA current in SOA. The side mode suppression ratio (SMSR) of the spectrum is better than 40 dB.

Naval Outgoing Message Processing, A Study of Message Generation and Message Preparation for Transmission and the Impact of Automation.

DTIC Science & Technology

1979-12-01

AM AM .m Itp 3MM"fvob 3MMopo" INA 7M 3M. St Z is pu~ e posep 3MM 3MMoar INA 3M 3MM St. 3M. Y" M3L-SINA1I 334IopAsoe * w*; INAt e M IM0NA .6.6.36...C or 20 ma current loop Current loop (60V. 60 ma) High level (±80V, 20 ma) INA Yes Yes Yes Same sIBM SELECTRIC Yes INA INA INA INA INA INA INA INA

The Apuseni Mountains, Romania, a Variscan Collage of Ordovician Gondwanan Terranes

NASA Astrophysics Data System (ADS)

Balintoni, I. C.; Balica, C.; Zaharia, L.; Chen, F.; Cliveti, M.; Hann, H. P.; Ghergari, L.

2007-12-01

The basement of the Apuseni Mountains, Romania, consists of three pre-Variscan terranes, sutured during an Early Variscan amalgamation around 351 Ma (Balintoni et al., this volume). The northern Someş Terrane (ST) is predominantly gneissic, while the southern Baia de Arieş Terrane (BAT) is dominated by the presence of large carbonate lenses, although metagranites and other types of orthogneisses can be found. These two terranes are sutured through the Biharia terrane, probably an accreted island arc. LA-ICP-MS datings on zircons extracted from orthogneisses and metagranites were performed in order to constrain the age of ST and BAT. A number of previously CL-imaged crystals were ablated at the China's University of Geosciences, Wuhan. From ST we dated an orthogneiss occurring in structurally lowermost position, a metatuff situated in the upper strongly retrogressed part and a twenty detrital crystal population sampled from a metasandstone. The 206Pb/238U apparent ages were projected using the weighted average plots.A magmatic crystallization age of 472.8±5.0 Ma (Upper Early Ordovician) resulted for one of the orthogneiss samples, besides several older ages at 505.7, 566.3 and 708.2 Ma corresponding to inherited cores. Another sample from the same rock appeared strongly affected by lead loss during a later thermotectonic event, most of the apparent ages grouping around 352±14 Ma. This age is similar with the age of the suture between ST and BT (Balintoni et al., this volume). The main zircon population of one metatuff sample furnished an averaged age of 423±7.2 Ma, also found in two additional samples, but their significance is obscure for the moment. Two primary magmatic ages arise at 464.2 and 473.8 Ma, an older value of 758.7 Ma corresponding to an inherited core. Detrital zircon ages range between 534.8 and 2596.8 Ma. The younger value represents an upper age constraint for the protolith age of ST-rocks. From BAT we dated the Lupşa metaporphyroid and the Mihoeşti (MiG) and Muncel (MuG) metagranites. The 466±11 Ma age value recorded in the metaporphyroid was inferred to represent the primary crystallization age. Many inherited cores yielded ages scattered between 523±32 Ma and 1914 Ma, while no ages younger then 466±11 Ma were recorded. The MiG crystallized at 469.2±7.5 Ma, inherited ages of 501±22, 554.9 and 685.6 Ma being also recorded. A 468.4±4.8 Ma primary magmatic age was found for the MuG, this sample also containing abundant inherited ages dispersed between 507.3±5.5 Ma and 1018.2 Ma. A group of ages at 429±13 Ma, corresponds to the dominant population in the ST metatuff. The results indicate that the main episode of crustal construction for the ST and BAT was the Ordovician; both terranes possess an abundant Cadomian inheritance. Pre-Cadomian inheritances are rare, except for the detrital zircons. Only the zircons from the ST appear strongly affected by lead loss processes, possibly related with the profuse Variscan magmatism affecting the upper plate. The history of the ST and BAT is compatible with a primitive North-Gondwanan origin.

75 FR 77529 - Traffic Separation Schemes: In the Approaches to Portland, ME; Boston, MA; Narragansett Bay, RI...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-13

...-AB55 Traffic Separation Schemes: In the Approaches to Portland, ME; Boston, MA; Narragansett Bay, RI... schemes in the approaches to Portland, ME; in the approaches to Boston, MA; in the approaches to... Coast Guard updates the current regulations for the traffic separation scheme in the approaches to...

Reconstruction of ionic currents in a molluscan photoreceptor.

PubMed Central

Sakakibara, M.; Ikeno, H.; Usui, S.; Collin, C.; Alkon, D. L.

1993-01-01

Two-microelectrode voltage-clamp measurements were made to determine the kinetics and voltage dependence of ionic currents across the soma membrane of the Hermissenda type B photoreceptor. The voltage-dependent outward potassium currents, IA and ICa(2+)-K+, the inward voltage-dependent calcium current, ICa2+ and the light-induced current, IIgt, were then described with Hodgkin-Huxley-type equations. The fast-activating and inactivating potassium current, IA, was described by the equation; IA(t) = gA(max)(ma infinity[1-exp(-t/tau ma)])3 x (ha infinity [1-exp(-t/tau ha)] + exp(-t/tau ha)) (Vm-EK), where the parameters ma infinity, ha infinity, tau ma, and tau ha are functions of membrane potential, Vm, and ma infinity and ha infinity are steady-state activation and inactivation parameters. Similarly, the calcium-dependent outward potassium current, ICa(2+)-K+, was described by the equation, ICa(2+)-K+ (t) = gc(max)(mc infinity(VC)(1-exp[-t/tau mc (VC)]))pc (hc infinity(VC) [1-exp(-t/tau hc)] + exp(-t/tau hc(VC)])pc(VC-EK). In high external potassium, ICa(2+)-K+ could be measured in approximate isolation from other currents as a voltage-dependent inward tail current following a depolarizing command pulse from a holding potential of -60 mV. A voltage-dependent inward calcium current across the type B soma membrane, ICa2+, activated rapidly, showed little inactivation, and was described by the equation: ICa2+ = gCa(max) [1 + exp](-Vm-5)/7]-1 (Vm-ECa), where gCa(max) was 0.5 microS. The light-induced current with both fast and slow phases was described by: IIgt(t) = IIgt1 + IIgt2 + IIgt3, IIgti = gIgti [1-exp(- ton/tau mi)] exp(-ton/tau hi)(Vm-EIgti) (i = 1, 2). For i = 3, /Igt(t) = gigt3m33h3(Vm - Eigt3)exp(-ton/Ton) x exp(-tfoff/t Off). Based on these reconstructions of ionic currents, learning-induced enhancement of the long lasting depolarization (LLD) of the photoreceptor'slight response was shown to arise from progressive inactivation of /A, lca2+ -K+, and lCa2+. PMID:8369456

Sulfoxidation Regulation of Musa acuminata Calmodulin (MaCaM) Influences the Functions of MaCaM-Binding Proteins.

PubMed

Jiang, Guoxiang; Wu, Fuwang; Li, Zhiwei; Li, Taotao; Gupta, Vijai Kumar; Duan, Xuewu; Jiang, Yueming

2018-06-01

Sulfoxidation of methionine in proteins by reactive oxygen species can cause conformational alteration or functional impairment, and can be reversed by methionine sulfoxide reductase (Msr). Currently, only a few potential Msr substrates have been confirmed in higher plants. Here, we investigated Msr-mediated sulfoxidation regulation of calmodulin (CaM) and its underlying biological significance in relation to banana fruit ripening and senescence. Expression of MaCaM1 and MaMsrA7 was up-regulated with increased ripening and senescence. We verified that MaCaM1 interacts with MaMsrA7 in vitro and in vivo, and sulfoxidated MaCaM1 could be partly repaired by MaMsrA7 (MaMsrA7 reduces oxidized residues Met77 and Met110 in MaCaM1). Furthermore, we investigated two known CaM-binding proteins, catalase (MaCAT1) and MaHY5-1. MaHY5-1 acts as a transcriptional repressor of carotenoid biosynthesis-related genes (MaPSY1, MaPSY2 and MaPSY3) in banana fruit. MaCaM1 could enhance the catalytic activity of MaCAT1 and the transcriptional repression activity of MaHY5-1 toward MaPSY2. Mimicked sulfoxidation in MaCaM1 did not affect the physical interactions of the protein with MaHY5-1 and MaCAT1, but reduced the catalytic activity of MaCAT1 and the transcriptional repression activity of MaHY5-1. Our data suggest that sulfoxidation modification in MaCaM1 by MaMsrA7 regulates antioxidant response and gene transcription, thereby being involved in regulation of ripening and senescence of banana fruit.

Dietary supplementation with DHA-rich microalgae improves performance, serum composition, carcass trait, antioxidant status, and fatty acid profile of broilers.

PubMed

Long, S F; Kang, S; Wang, Q Q; Xu, Y T; Pan, L; Hu, J X; Li, M; Piao, X S

2018-06-01

This experiment was conducted with 126 as-hatched male Arbor Acres chicks (1-d-old, weighing 45.3 ± 0.72 g) to determine the effects of microalgae [MA, containing 29% docosahexaenoic acid (DHA)] on performance, serum composition, carcass trait, antioxidant status, and fatty acid deposition of birds. The birds were allocated randomly to 1 of 3 treatments with 7 replicate pens per treatment (6 birds per pen). The dietary treatments included a control diet [corn-soybean basal diet supplemented with 3% soybean oil (SO), CON], 1% MA diet (basal diet supplemented with 1% MA and 2% SO, 1MA), and 2% MA diet (basal diet supplemented with 2% MA and 1% SO, 2MA). All birds were raised in wire-floored cages. The trial consists of a starter phase from d 1 to 21 and a grower phase from d 22 to 42. Compared with CON, birds supplemented with MA (1MA or 2MA) had greater (P < 0.05) average daily gain, liver percentage (liver weight/body weight), and serum glucose, as well as lower (P < 0.05) feed conversation ratio, abdominal fat percentage (abdominal fat weight/body weight), and total serum cholesterol. Moreover, due to the high concentration of DHA in MA, birds fed MA showed increased (P < 0.05) concentration of eicosapentaenoic acid, DHA, superoxide dismutase, and total antioxidant capacity, as well as decreased (P < 0.05) n-6/n-3 polyunsaturated fatty acid ratio, polyunsaturated fatty acid/saturated fatty acid ratio, and malondialdehyde in the breast and thigh muscle compared with CON. In conclusion, dietary supplementation with 1% or 2% DHA-rich microalgae had positive effects on performance, serum composition, carcass trait, antioxidant status, and fatty acid deposition in birds.

New Rb-Sr mineral ages temporally link plume events with accretion at the margin of Gondwana

USGS Publications Warehouse

Flowerdew, M.J.; Daly, J.S.; Riley, T.R.

2007-01-01

Five of six Rb-Sr muscovite mineral isochron ages from the Scotia Metamorphic Complex of the South Orkney Islands, West Antarctica, average 190 ± 4 Ma. The muscovite ages are interpreted to date foliation-formation and thus also accretion and subduction at the Gondwana margin. Coincident picrite and ferropicrite magmatism, indicative of melts from deep-seated depleted mantle, permits a causative link between accretion and the arrival of the Karoo – Ferrar – Chon Aike mantle plume in the Early Jurassic. Three biotite Rb-Sr mineral isochron ages are consistently younger and average 176 ± 5 Ma. The biotite ages may record post-metamorphic cooling or more likely retrogressive metamorphic effects during uplift.

Pharmaceutical Market Access: current state of affairs and key challenges - results of the Market Access Launch Excellence Inventory (MALEI).

PubMed

Koch, Marcus A

2015-01-01

To take inventory of the current state of affairs of Market Access Launch Excellence in the life sciences industry. To identify key gaps and challenges for Market Access (MA) and discuss how they can be addressed. To generate a baseline for benchmarking MA launch excellence. An online survey was conducted with pharmaceutical executives primarily working in MA, marketing, or general management. The survey aimed to evaluate MA excellence prerequisites across the product life cycle (rated by importance and level of implementation) and to describe MA activity models in the respective companies. Composite scores were calculated from respondents' ratings and answers. Implementation levels of MA excellence prerequisites generally lagged behind their perceived importance. Item importance and the respective level of implementation correlated well, which can be interpreted as proof of the validity of the questionnaire. The following areas were shown to be particularly underimplemented: 1) early integration of MA and health economic considerations in research and development decision making, 2) developing true partnerships with payers, including the development of services 'beyond the pill', and 3) consideration of human resource and talent management. The concept of importance-adjusted implementation levels as a hybrid parameter was introduced and shown to be a viable tool for benchmarking purposes. More than 70% of respondents indicated that their companies will invest broadly in MA in terms of capital and headcount within the next 3 years. MA (launch) excellence needs to be further developed in order to close implementation gaps across the entire product life cycle. As MA is a comparatively young pharmaceutical discipline in a complex and dynamic environment, this effort will require strategic focus and dedication. The Market Access Launch Excellence Inventory benchmarking tool may help guide decision makers to prioritize their endeavors.

Power Balance Modeling and Validation for ST Startup Using Local Helicity Injection

NASA Astrophysics Data System (ADS)

Barr, J. L.; Bodner, G. M.; Bongard, M. W.; Burke, M. G.; Fonck, R. J.; Hinson, E. T.; Perry, J. M.; Reusch, J. A.; Schlossberg, D. J.

2015-11-01

Local Helicity Injection (LHI) uses localized current injectors for routine Ip<0.18 MA non-solenoidal startup on the Pegasus ST. A power-balance model is under development for predictive Ip t using helicity-balance to quantify LHI's effective current drive, Veff. Analytic formulas for low-A plasma inductance and vertical field are used to account for the inductive effects of dynamic shape evolution. These formulas are being validated against magnetic reconstructions of LHI discharges with varied shape evolutions. Initial results match experimental Ip t within 20 kA with assumed shaping and average resistivity (Spitzer, Te = 60 eV). Geometric effects and inductive drive provide 2.0 V along with Veff = 0.3 V to balance 1.1 V of resistive losses and 1.2 V inductive reactance to ramping Ip. The model is especially sensitive to resistivity when Te<150 eV. Initial Thomson Scattering results give core Te = 72 +/-22 eV, and at times suggest higher central electron energies. Spatial and temporal scans are underway to quantify LHI plasma resistivity and transport. MA-class startup in NSTX-U will require increased area (Ainj >= 40 cm2) LHI systems that play a larger role in current drive than geometric effects, with Veff dropping from >10 V to on-par with inductive effects. This regime is accessed in Pegasus at Ip ≅ 300 kA. Work supported by US DOE grants DE-FG02-96ER54375 and DE-SC0006928.

Northwest African Continental Margin: History of sediment accumulation, landslide deposits, and hiatuses as revealed by drilling the Madeira Abyssal Plain

NASA Astrophysics Data System (ADS)

Weaver, P. P. E.

2003-03-01

ODP drill sites in the Madeira Abyssal Plain reveal sequences of organic-rich turbidites derived from the northwest African margin, in which each turbidite has a volume of tens to hundreds of cubic kilometers. The frequency of turbidite emplacement has been combined with core and seismic data to show the volume of redeposited sediment. The basin began to fill about 22 Ma with numerous small turbidites, up to 100 per million years, each with volumes of a few cubic kilometers. The total volume of turbidites deposited increased between 16 and 11 Ma, as did their individual volumes, and then declined to 7 Ma. At 7 Ma, there was a dramatic increase in the amount of turbidite input to 768 km3/Myr and a rise in the average volume of each unit to 59 km3. These high values have been maintained to the present day. The variations in the amount of redeposited sediment most likely reflect the rates of sedimentation on the northwest African margin since high sedimentation leads to oversteepening of the slopes and eventual mass wasting. The dramatic changes at about 7 Ma may be due to a large increase in upwelling off northwest Africa caused by circulation changes associated with increased glaciation of the poles. Up to 20% of sediment may be remobilized by landslides, with each event leaving a hiatus. Each of these hiatuses extends over an average area of ˜4800 km2 and represents removal of sediment layers several tens of meters thick and of several hundred thousand years duration.

The relationship between retinal damage and current intensity in a pre-clinical suprachoroidal-transretinal stimulation model using a laser-formed microporous electrode

NASA Astrophysics Data System (ADS)

Kanda, Hiroyuki; Nakano, Yukari; Terasawa, Yasuo; Morimoto, Takeshi; Fujikado, Takashi

2017-10-01

Objective. Suprachoroidal-transretinal stimulation (STS) is a stimulation method for retinal prostheses. For STS-type retinal prostheses, we developed a new type of stimulating electrode called a femtosecond laser-induced porous electrode (FLiP electrode). To verify the safety of the FLiP electrode for STS, we investigated the characteristics of STS-induced retinal injury. Approach. Sixteen eyes of pigmented rabbits were studied in this in vivo study. For each examined eye, we implanted a single-channel FLiP electrode (diameter, 0.5 mm height, 0.3 mm geometric surface area, 0.43 mm2) in a scleral pocket created at the posterior pole of the eye. A return electrode (diameter, 0.5 mm length, 3 mm) was inserted into the vitreous cavity. The eyes were divided into five groups, and each group was stimulated with a different current intensity. The stimulus intensities and the number of eyes in each group were as follows: 1.0 mA (n  =  2), 1.5 mA (n  =  3), 2.0 mA (n  =  3), 2.5 mA (n  =  4), and 3.0 mA (n  =  2). Continuous biphasic pulses (0.5 ms/phase) were applied under general anesthesia at a frequency of 20 Hz for 48 h. Fundus photography, fluorescein angiography (FA), and optical coherence tomography were performed before and after applying the electrical stimulation to evaluate the retinal injury. Main results. The 1.0 mA and 1.5 mA groups showed little or no retinal damage. Fluorescent dye leakage in FA and punctate pigmentation in the fundus were observed around the stimulation site with stimulation of 2.0 mA (1/3), 2.5 mA (1/4), and 3.0 mA (2/2). Significance. Our findings indicate that the threshold current for inducing retinal damage is greater than that for eliciting electrical phosphenes (<1 mA) with STS observed in human trials. Therefore, STS by the FLiP electrode is a safe and feasible stimulation method for retinal prostheses as long as it is used with these pulse parameters.

Loss-of-function and gain-of-function phenotypes of stomatocytosis mutant RhAG F65S

PubMed Central

Stewart, Andrew K.; Shmukler, Boris E.; Vandorpe, David H.; Rivera, Alicia; Heneghan, John F.; Li, Xiaojin; Hsu, Ann; Karpatkin, Margaret; O'Neill, Allison F.; Bauer, Daniel E.; Heeney, Matthew M.; John, Kathryn; Kuypers, Frans A.; Gallagher, Patrick G.; Lux, Samuel E.; Brugnara, Carlo; Westhoff, Connie M.

2011-01-01

Four patients with overhydrated cation leak stomatocytosis (OHSt) exhibited the heterozygous RhAG missense mutation F65S. OHSt erythrocytes were osmotically fragile, with elevated Na and decreased K contents and increased cation channel-like activity. Xenopus oocytes expressing wild-type RhAG and RhAG F65S exhibited increased ouabain and bumetanide-resistant uptake of Li+ and 86Rb+, with secondarily increased 86Rb+ influx sensitive to ouabain and to bumetanide. Increased RhAG-associated 14C-methylammonium (MA) influx was severely reduced in RhAG F65S-expressing oocytes. RhAG-associated influxes of Li+, 86Rb+, and 14C-MA were pharmacologically distinct, and Li+ uptakes associated with RhAG and RhAG F65S were differentially inhibited by NH4+ and Gd3+. RhAG-expressing oocytes were acidified and depolarized by 5 mM bath NH3/NH4+, but alkalinized and depolarized by subsequent bath exposure to 5 mM methylammonium chloride (MA/MA+). RhAG F65S-expressing oocytes exhibited near-wild-type responses to NH4Cl, but MA/MA+ elicited attenuated alkalinization and strong hyperpolarization. Expression of RhAG or RhAG F65S increased steady-state cation currents unaltered by bath Li+ substitution or bath addition of 5 mM NH4Cl or MA/MA+. These oocyte studies suggest that 1) RhAG expression increases oocyte transport of NH3/NH4+ and MA/MA+; 2) RhAG F65S exhibits gain-of-function phenotypes of increased cation conductance/permeability, and loss-of-function phenotypes of decreased and modified MA/MA+ transport, and decreased NH3/NH4+-associated depolarization; and 3) RhAG transports NH3/NH4+ and MA/MA+ by distinct mechanisms, and/or the substrates elicit distinct cellular responses. Thus, RhAG F65S is a loss-of-function mutation for amine transport. The altered oocyte intracellular pH, membrane potential, and currents associated with RhAG or RhAG F65S expression may reflect distinct transport mechanisms. PMID:21849667

Cenozoic Circulation History of the North Atlantic Ocean From Seismic Stratigraphy of the Newfoundland Ridge Drift Complex

NASA Astrophysics Data System (ADS)

Boyle, P. R.; Romans, B.; Norris, R. D.; Tucholke, B. E.; Swift, S. A.; Sexton, P. F.

2014-12-01

In the North Atlantic Ocean, contour-following bottom currents have eroded regional unconformities and deposited contourite drifts that exceed two km in thickness and extend for 100s of km. The character of deep-water masses that are conveyed through ocean basins by such currents influence global heat transfer and ocean-atmosphere partitioning of CO2. The Newfoundland Ridge Drift Complex lies directly under the modern Deep Western Boundary Current southeast of Newfoundland, close to the site of overturning in the northwest Atlantic Ocean and at the intersection of the warm Gulf Stream and cool Labrador surface currents. To the south are regions of the western North Atlantic basin that are influenced by southern- as well as northern-sourced bottom waters. Here, we document the evolution of North Atlantic deep-water circulation by seismic-stratigraphic analysis of the long-lived and areally extensive Newfoundland Ridge Drift Complex. IODP Expedition 342 boreholes provide age control on seismic units, allowing sedimentation patterns to be placed in a temporal framework. We find three major phases of sedimentation: pre-contourite drift (~115-50 Ma), active contourite drift (~50-2.6 Ma), and late-contourite drift (~2.6-0 Ma). Bottom-current-controlled deposition of terrigenous-rich sediment began at ~50 Ma, which correlates to the onset of a long-term global cooling trend. A further change in deep circulation near the Eocene-Oligocene transition (~30 Ma) is indicated by more focused drift sedimentation with greatly increased accumulation rates and stratal architecture dominated by mud waves. At ~2.6 Ma to present the axis of drift accumulation shifted markedly towards shallower water depths, corresponding with the onset of Northern Hemisphere ice sheets. We discuss how these reorganizations of deep circulation correlate with results of other North Atlantic seismic stratigraphic studies to the north and south.

High current DC negative ion source for cyclotron

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

Etoh, H., E-mail: Hrh-Etoh@shi.co.jp; Aoki, Y.; Mitsubori, H.

2016-02-15

A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H{sup −} beam of 10 mA and D{sup −} beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H{sup −} beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H{sup −} current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. Themore » relationship between H{sup −} production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H{sup −} current dependence on the arc power.« less

Development of a beam line for radio-isotope production at the KOMAC

NASA Astrophysics Data System (ADS)

Kim, Han-Sung

2016-09-01

A new beam line of the 100-MeV proton linac at the KOMAC (Korea Multi-purpose Accelerator Complex), aiming for RI (radioisotope) production has been constructed reflecting the increasing demands for various RIs (radioisotopes), such as Sr-82 and Cu-67 for medical applications. Proton beam with beam energy of 100 MeV and an average current of 0.6 mA is directed to the 100-mm-diameter production target through a beam window made of aluminum-beryllium alloy. Major components of the newly-installed beam line include electromagnets for bending and focusing, beam diagnostic systems such as a BPM (beam position monitor) and a BCM (beam current monitor), and a vacuum pumping system based on an ion pump. In this paper, the design features and the installation of the RI-production beam line at the KOMAC are given.

Investigation of heavy current discharges with high initial gas density

NASA Astrophysics Data System (ADS)

Budin, A.; Bogomaz, A.; Kolikov, V.; Kuprin, A.; Leontiev, V.; Rutberg, Ph.; Shirokov, N.

1996-05-01

Piezoelectric pressure transducers, with noise immunity and time resolution of 0,5 μs were used to measure pulse pressures of 430 MPa along the axis of an electrical discharge channel. Initial concentration of He was 2,7ṡ1021cm-3, dI/dt=6ṡ1011 A/s, and Imax=560 kA. Shock waves with amplitudes exceeding the pressure along the axis, were detected by a pressure transducer on the wall of the discharge chamber. Typical shock velocities were 2ṡ4 km/s. Average pressure measurements along the discharge axis at different radii were used to estimate the current density distribution along the canal radius. The presence of the shock waves, promoting the additional hydrogen heating in the discharge chamber, has been registered during the discharge in hydrogen for Imax˜1 MA and an initial concentration of 1021cm-3.

Design and development of electrical impedance tomography system with 32 electrodes and microcontroller

NASA Astrophysics Data System (ADS)

Ansory, Achmad; Prajitno, Prawito; Wijaya, Sastra Kusuma

2018-02-01

Electrical Impedance Tomography (EIT) is an imaging method that is able to estimate electrical impedance distribution inside an object. This EIT system is developed by using 32 electrodes and microcontroller based module. From a pair of electrodes, sinusoidal current of 3 mA is injected and the voltage differences between other pairs of electrodes are measured. Voltage measurement data are then sent to MATLAB and EIDORS software; the data are used to reconstruct two dimensions image. The system can detect and determine the position of a phantom in the tank. The object's position is accurately reconstructed and determined with the average shifting of 0.69 cm but object's area cannot be accurately reconstructed. The object's image is more accurately reconstructed when the object is located near to electrodes, has a larger size, and when the current injected to the system has a frequency of 100 kHz or 200kHz.

SIN accelerator, operational experience and improvement programs

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

Joho, W.; Olivo, M.; Stammbach, T.

1977-06-01

The SIN meson facility, in operation since 1974, consists of a 590 MeV ring cyclotron for protons and a 72 MeV injector cyclotron. The average beam current on target is presently about 50 ..mu..A, the peak being 112 ..mu..A. Extraction efficiency, once considered a severe handicap for cyclotrons, is now 99.6 to 99.9% for the ring cyclotron and about 90% for the injector. Many improvements in both accelerators allow single turn extraction in the ring cyclotron. The present current limit is given by the injector, while the ring itself could accept now a 600 ..mu..A beam, with 2 to 4more » mA as an ultimate limit. Some muon experiments require a pulsed beam with on-off times in the order of the lifetime of the muon. First trials with beam pulse frequencies of 200 and 400 kHz and a 50% duty cycle have been successful.« less

Surface plasma source with saddle antenna radio frequency plasma generator.

PubMed

Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

2012-02-01

A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

Construction of Hierarchical CuO/Cu2O@NiCo2S4 Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes

PubMed Central

Zhou, Luoxiao; He, Ying; Jia, Congpu; Pavlinek, Vladimir; Saha, Petr; Cheng, Qilin

2017-01-01

Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu2O@NiCo2S4) core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu2O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo2S4 nanosheets on the surface of CuO/Cu2O nanowires to form the CuO/Cu2O@NiCo2S4 core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo2S4 nanosheets is ~20 nm and the diameter of CuO/Cu2O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm−2 at 10 mA cm−2, good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm−2) and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm−2. These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer. PMID:28914819

Magnesium Hydride Nanoparticles Self-Assembled on Graphene as Anode Material for High-Performance Lithium-Ion Batteries.

PubMed

Zhang, Baoping; Xia, Guanglin; Sun, Dalin; Fang, Fang; Yu, Xuebin

2018-04-24

MgH 2 nanoparticles (NPs) uniformly anchored on graphene (GR) are fabricated based on a bottom-up self-assembly strategy as anode materials for lithium-ion batteries (LIBs). Monodisperse MgH 2 NPs with an average particle size of ∼13.8 nm are self-assembled on the flexible GR, forming interleaved MgH 2 /GR (GMH) composite architectures. Such nanoarchitecture could effectively constrain the aggregation of active materials, buffer the strain of volume changes, and facilitate the electron/lithium ion transfer of the whole electrode, leading to a significant enhancement of the lithium storage capacity of the GMH composite. Furthermore, the performances of GMH composite as anode materials for LIBs are enabled largely through robust interfacial interactions with poly(methyl methacrylate) (PMMA) binder, which plays multifunctional roles in forming a favorable solid-electrolyte interphase (SEI) film, alleviating the volume expansion and detachment of active materials, and maintaining the structural integrity of the whole electrode. As a result, these synergistic effects endow the obtained GMH composite with a significantly enhanced reversible capacity and cyclability as well as a good rate capability. The GMH composite with 50 wt % MgH 2 delivers a high reversible capacity of 946 mA h g -1 at 100 mA g -1 after 100 cycles and a capacity of 395 mAh g -1 at a high current density of 2000 mA g -1 after 1000 cycles.

42 CFR 423.251 - Scope.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., review, negotiation and approval of competitive bids for prescription drug plans and MA-PD plans; the calculation of the national average bid amount; and the determination of enrollee premiums. ...

Can Anxiety Tested in the Elevated Plus-maze Be Related to Nociception Sensitivity in Adult Male Rats?

PubMed

Pometlová, Marie; Yamamotová, Anna; Nohejlová, Kateryna; Šlamberová, Romana

Methamphetamine (MA) is one of the most addictive psychostimulant drugs with a high potential for abuse. Our previous studies demonstrated that MA administered to pregnant rats increases pain sensitivity and anxiety in their adult offspring and makes them more sensitive to acute administration of the same drug in adulthood. Because individuals can differ considerably in terms of behaviour and physiology, such as rats that do not belong in some characteristics (e.g. anxiety) to average, can be described as low-responders or high-responders, are then more or less sensitive to pain. Therefore, prenatally MA-exposed adult male rats treated in adulthood with a single dose of MA (1 mg/ml/kg) or saline (1 ml/kg) were tested in the present study. We examined the effect of acute MA treatment on: (1) the anxiety in the Elevated plus-maze (EPM) test and memory in EPM re-test; (2) nociception sensitivity in the Plantar test; (3) the correlation between the anxiety, memory and the nociception. Our results demonstrate that: (1) MA has an anxiogenic effect on animals prenatally exposed to the same drug in the EPM; (2) all the differences induced by acute MA treatment disappeared within the time of 48 hours; (3) there was no effect of MA on nociception per se, but MA induced higher anxiety in individuals less sensitive to pain than in animals more sensitive to pain. In conclusion, the present study demonstrates unique data showing association between anxiety and nociceptive sensitivity of prenatally MA-exposed rats that is induced by acute drug administration.

Relationships between Medicare Advantage contract characteristics and quality-of-care ratings: an observational analysis of Medicare Advantage star ratings.

PubMed

Xu, Peng; Burgess, James F; Cabral, Howard; Soria-Saucedo, Rene; Kazis, Lewis E

2015-03-03

The Centers for Medicare & Medicaid Services (CMS) publishes star ratings on Medicare Advantage (MA) contracts to measure plan quality of care with implications for reimbursement and bonuses. To investigate whether MA contract characteristics are associated with quality of care through the Medicare plan star ratings. Retrospective study of MA star ratings in 2010. Unadjusted and adjusted multivariable linear regression models assessed the relationship between 5-star rating summary scores and plan characteristics. CMS MA contracts nationally. 409 (71%) of a total of 575 MA contracts, covering 10.56 million Medicare beneficiaries (90% of the MA population) in the United States in 2010. The MA quality ratings summary score (stars range from 1 to 5) is a quality measure based on 36 indicators related to processes of care, health outcomes, access to care, and beneficiary satisfaction. Nonprofit, larger, and older MA contracts were more likely to receive higher star ratings. Star ratings ranged from 2 to 5. Nonprofit contracts received an average 0.55 (95% CI, 0.42 to 0.67) higher star ratings than for-profit contracts (P  < 0.001) after controls were set for contract characteristics. The study focused on persons aged 65 years or older covered by MA. In 2010, nonprofit MA contracts received significantly higher star ratings than for-profit contracts. When comparing health plans in the future, the CMS should give increasing attention to for-profit plans with lower quality ratings and consider developing programs to assist newer and smaller plans in improving their care for Medicare beneficiaries. None.

Monolithic integration of a GaAlAs buried-heterostructure laser and a bipolar phototransistor

NASA Technical Reports Server (NTRS)

Bar-Chaim, N.; Harder, CH.; Margalit, S.; Yariv, A.; Katz, J.; Ury, I.

1982-01-01

A GaAlAs buried-heterostructure laser has been monolithically integrated with a bipolar phototransistor. The heterojunction transistor was formed by the regrowth of the burying layers of the laser. Typical threshold current values for the lasers were 30 mA. Common-emitter current gains for the phototransistor of 100-400 and light responsitivity of 75 A/W (for wavelengths of 0.82 micron) at collector current levels of 15 mA were obtained.

Recalibration of the Palaeocene-Eocene boundary (P-E) using high precision U-Pb and Ar-Ar isotopic dating

NASA Astrophysics Data System (ADS)

Chambers, L.; Pringle, M.; Fitton, G.; Larsen, L. M.; Pedersen, A. K.; Parrish, R.

2003-04-01

In the current time scales (Cande and Kent, 95; Berggren et al, 95) the P-E Boundary is positioned at 55 Ma based primarily on the age of the -17 ash layer in Denmark. In the absence of a global stratigraphic section and point the boundary is an interval of 1 m.y. from 55.5 to 54.5 Ma that includes all of the different means of calibrating the boundary tie point, including the NP9/NP10 calcareous nannofossil zonal boundary, the planktonic foraminiferal P5/P6a zonal boundary, preliminary ages for the -17 and +19 ash layers (unpub.), the base of the London Clay Formation, and the δ13C spike. Here we present new Ar-Ar ages for the -17 and +19 ash layers in Denmark and combine this study with a calibration of the Ar-Ar with the U-Pb method. As Ar-Ar ages are relative to the known age of a standard or monitor, U-Pb ages on zircons from the same rocks from the British Tertiary Igneous Province provide an absolute age calibration for all of our Ar-Ar ages (including the monitors). An additional complication arises because the time scale is currently being revised (J. Ogg, Pers. Comm.). In the new time scale the P-E boundary will stay at 55 Ma and the K-T boundary will move by 0.5 m.y. to 65.5 Ma. Our results have a direct impact on the positioning of the P-E Boundary relative to the K-T boundary as definitive K-T tektite is used as one of our Ar-Ar standards. Ar-Ar ages and U-Pb ages for the same sample from the BTIP are indistinguishable when the ages used for the Ar-Ar monitor minerals are those recommended in Renne et al (98). This means that the K-T tektite is 65.78 ± 0.03 Ma, the -17 ash is 54.52 ± 0.05Ma, and the +19 ash is 54.04 ± 0.14 Ma. If the P-E boundary is taken to be between the -17 and +19 ash layers, as in DSDP Hole 550 (the ashes bracket the planktonic foraminiferal P5/P6a zonal boundary) then the current position at 55 Ma is too old. We therefore suggest that if the K-T boundary moves to 65.5 Ma, then the P-E boundary should not stay at 55 Ma, but move to 54.5 Ma (extending the Palaeocene by 1 m.y.). If the K-T boundary does not move by 0.5 m.y. then the P-E boundary would still have to move from its current position at 55 Ma and the ages used for the argon monitor minerals revised.

Quite a lot of smoke but very limited fire--the use of methamphetamine in Europe.

PubMed

Griffiths, Paul; Mravcik, Viktor; Lopez, Dominique; Klempova, Danica

2008-05-01

This paper provides an overview of the historical development, current situation and potential future diffusion of methamphetamine (MA) use in Europe. The analysis is based on a review of published and grey literature, as well as data collected as part of the ongoing monitoring of the drug situation in Europe. Some qualitative surveys among high-risk populations do exist, but overall the general low prevalence of methamphetamine use in most of Europe means that the data available to explore patterns of use are limited. In many parts of Europe, amphetamine use is well established and the injecting of amphetamines has historically constituted an important component of the drug problem in many Nordic countries. Methamphetamine problems are long documented in the Czech and Slovak republics, but there is no current evidence of widespread use of MA elsewhere in Europe. Concern that MA use is spreading in Europe is prompted by some reports of use among high-risk groups. However, the evidence available suggests that even in high-risk populations, the use of MA currently remains uncommon. Europe accounted for less than 1% of worldwide MA seizures in 2005, and over the period 2004-05 European ephedrine seizures amounted for 6% of the global figure. The spread of MA use is limited and no strong evidence exists that significant diffusion is occurring. It appears likely that methamphetamine diffusion in Europe is impeded by a strong market for other stimulant drugs [cocaine, amphetamine and methylenedioxymethamphetamine (MDMA)]. The future potential for the diffusion of MA may be influenced by factors such as: the relative availability and popularity of other drugs; possible 'leakage' from areas of historical high prevalence; travel by young Europeans to areas of high prevalence; and how users perceive MA as a desirable, suitable and cost-effective alternative to other stimulants available on the European illicit drug market.

Influence of PP-g-MA compatibilizer characteristics on mechanical properties of glass fiber reinforced polypropylene composites

NASA Astrophysics Data System (ADS)

Guan, Zhuo

Glass fiber (GF) reinforced polypropylene (PP) has become a common composite material used for various applications. Previous reports indicated that grafting ratio and molecular weight (MW) of znaleic anhydride grafted polypropylene (PP-g-MA) are the two most significant factors affecting the mechanical properties of PP/PP-g-MA/GF composites, but the combined effect of these two factors remains controversial. The study of the importance of MA grafting ratio and MW is continued in this work using PPIPP-g MA/GF composites containing various grades and concentrations of PP-g MA compatibilizer. First, MFR and FT1R analyses were performed to characterize the physical and chemical properties- of each PP-g-MA resin. Then, premixed PP and PP-g-MA blend were compounded with GF via twin screw extrusion, with the compounds injection molded into tensile, flexural and Izod impact specimens (all ASTM standard) for mechanical properties testing. Generally speaking, at a given GF content, higher compatibilizer concentrations led to higher tensile, flexural and notched Izod impact strength up to an optimum MA concentrations above which these properties tended to level off PP-g-MA resins with higher grafting ratio were more efficient compatibilizers as indicated by improved tensile, flexural and impact properties at lower PP-g-MA contents. In addition, MW was expected to affect properties as well, with too high and too 16w MW values leading to reduced reinforcement. While the optimum MW values for tensile and impact strength were still not clear based on present results, the estimated optimum weight average MW for maximum flexural strength was 90,000 +/- 1,400 g/mol.

Cement Based Batteries and their Potential for Use in Low Power Operations

NASA Astrophysics Data System (ADS)

Byrne, A.; Holmes, N.; Norton, B.

2015-11-01

This paper presents the development of an innovative cement-electrolyte battery for low power operations such as cathodic protection of reinforced concrete. A battery design was refined by altering different constituents and examining the open circuit voltage, resistor loaded current and lifespan. The final design consisted of a copper plate cathode, aluminium plate anode, and a cement electrolyte which included additives of carbon black, plasticiser, Alum salt and Epsom salt. A relationship between age, temperature and hydration of the cell and the current it produced was determined. It was found that sealing the battery using varnish increased the moisture retention and current output. Current was also found to increase with internal temperature of the electrolyte and connecting two cells in parallel further doubled or even tripled the current. Parallel-connected cells could sustain an average current of 0.35mA through a 10Ω resistor over two weeks of recording. The preliminary findings demonstrate that cement-based batteries can produce sufficient sustainable electrical outputs with the correct materials and arrangement of components. Work is ongoing to determine how these batteries can be recharged using photovoltaics which will further enhance their sustainability properties.

Myocardial perfusion and left ventricular function indices assessed by gated myocardial perfusion SPECT in methamphetamine abusers.

PubMed

Dadpour, Bita; Dabbagh Kakhki, Vahid R; Afshari, Reza; Dorri-Giv, Masoumeh; Mohajeri, Seyed A R; Ghahremani, Somayeh

2016-12-01

Methamphetamine (MA) is associated with alterations of cardiac structure and function, although it is less known. In this study, we assessed possible abnormality in myocardial perfusion and left ventricular function using gated myocardial perfusion SPECT. Fifteen patients with MA abuse, on the basis of Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) MA dependency determined by Structured Clinical Interview for DSM-IV, underwent 2-day dipyridamole stress/rest Tc-sestamibi gated myocardial perfusion SPECT. An average daily dose of MA use was 0.91±1.1 (0.2-4) g. The duration of MA use was 3.4±2.1 (1-7) years. In visual and semiquantitative analyses, all patients had normal gated myocardial perfusion SPECT, with no perfusion defects. In all gated SPECT images, there was no abnormality in left ventricular wall motion and thickening. All summed stress scores and summed rest scores were below 3. Calculated left ventricular functional indices including the end-diastolic volume, end-systolic volume, and left ventricular ejection fraction were normal. Many cardiac findings because of MA mentioned in previous reports are less likely because of significant epicardial coronary artery stenosis.

Endovascular Catheter for Magnetic Navigation under MR Imaging Guidance: Evaluation of Safety in Vivo at 1.5T

PubMed Central

Hetts, S.W.; Saeed, M.; Martin, A.J.; Evans, L.; Bernhardt, A.F.; Malba, V.; Settecase, F.; Do, L.; Yee, E.J.; Losey, A.; Sincic, R.; Roy, S.; Arenson, R.L.; Wilson, M.W.

2013-01-01

BACKGROUND AND PURPOSE: Endovascular navigation under MR imaging guidance can be facilitated by a catheter with steerable microcoils on the tip. Not only do microcoils create visible artifacts allowing catheter tracking, but also they create a small magnetic moment permitting remote-controlled catheter tip deflection. A side product of catheter tip electrical currents, however, is the heat that might damage blood vessels. We sought to determine the upper boundary of electrical currents safely usable at 1.5T in a coil-tipped microcatheter system. MATERIALS AND METHODS: Alumina tubes with solenoid copper coils were attached to neurovascular microcatheters with heat shrink-wrap. Catheters were tested in carotid arteries of 8 pigs. The catheters were advanced under x-ray fluoroscopy and MR imaging. Currents from 0 mA to 700 mA were applied to test heating and potential vascular damage. Postmortem histologic analysis was the primary endpoint. RESULTS: Several heat-mitigation strategies demonstrated negligible vascular damage compared with control arteries. Coil currents ≤300 mA resulted in no damage (0/58 samples) compared with 9 (25%) of 36 samples for > 300-mA activations (P = .0001). Tip coil activation ≤1 minute and a proximal carotid guide catheter saline drip > 2 mL/minute also had a nonsignificantly lower likelihood of vascular damage. For catheter tip coil activations ≤300 mA for ≤1 minute in normal carotid flow, 0 of 43 samples had tissue damage. CONCLUSIONS: Activations of copper coils at the tip of microcatheters at low currents in 1.5T MR scanners can be achieved without significant damage to blood vessel walls in a controlled experimental setting. Further optimization of catheter design and procedure protocols is necessary for safe remote control magnetic catheter guidance. PMID:23846795

Intrinsic defect oriented visible region absorption in zinc oxide films

NASA Astrophysics Data System (ADS)

Rakhesh, V.; Shankar, Balakrishnan

2018-05-01

Zinc Oxide films were deposited on the glass substrate using vacuum arc sputtering technology. Films were prepared in oxygen ambience for 10mA and 15 mA deposition current separately. The UV-Visible spectroscopy of the samples showed that both samples possess sharp absorption near 3.5eV which is the characteristic band gap absorption energy of ZnO films. The absorption coefficient were calculated for the samples and the (αℎϑ)2 vs energy plot is drawn. The plot suggested that in addition to the sharp band edge absorption, the sample prepared at 10mA deposition current showed sharp absorption edge near 1.51eV and that at 15 mA showed absorption edge near 1.47eV. This refers to the presence of an intrinsic defect level which is likely to be deep in the band gap.

Metal coordination polymer derived mesoporous Co3O4 nanorods with uniform TiO2 coating as advanced anodes for lithium ion batteries.

PubMed

Geng, Hongbo; Ang, Huixiang; Ding, Xianguang; Tan, Huiteng; Guo, Guile; Qu, Genlong; Yang, Yonggang; Zheng, Junwei; Yan, Qingyu; Gu, Hongwei

2016-02-07

In this work, a one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g(-1), good cycling stability (around 803 mA h g(-1) at a current density of 200 mA g(-1) after 100 cycles), and stable rate performance (around 520 mA h g(-1) at a current density of 1000 mA g(-1)). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling.

Electrostatic spray deposition of porous SnO₂/graphene anode films and their enhanced lithium-storage properties.

PubMed

Jiang, Yinzhu; Yuan, Tianzhi; Sun, Wenping; Yan, Mi

2012-11-01

Porous SnO₂/graphene composite thin films are prepared as anodes for lithium ion batteries by the electrostatic spray deposition technique. Reticular-structured SnO₂ is formed on both the nickel foam substrate and the surface of graphene sheets according to the scanning electron microscopy (SEM) results. Such an assembly mode of graphene and SnO₂ is highly beneficial to the electrochemical performance improvement by increasing the electrical conductivity and releasing the volume change of the anode. The novel engineered anode possesses 2134.3 mA h g⁻¹ of initial discharge capacity and good capacity retention of 551.0 mA h g⁻¹ up to the 100th cycle at a current density of 200 mA g⁻¹. This anode also exhibits excellent rate capability, with a reversible capacity of 507.7 mA h g⁻¹ after 100 cycles at a current density of 800 mA g⁻¹. The results demonstrate that such a film-type hybrid anode shows great potential for application in high-energy lithium-ion batteries.

Initial Closure of the Neo-Tethys and Kinematics of the Arabian Crustal Shortening

NASA Astrophysics Data System (ADS)

Pirouz, M.; Avouac, J. P.; Hassanzadeh, J.; Kirschvink, J. L.; Bahroudi, A.

2017-12-01

Exposed transition from passive margin to foreland basin sedimentation in the High Zagros provides chronological constraints on the initial stage of Arabia-Eurasia collision and closure of the Neo-Tethys. Magnetostratigraphy and strontium isotope stratigraphy along two sections near the Zagros suture display that the top of the passive margin Asmari formation has an age of 28 - 29 Ma and is overlain by foreland deposits with a major hiatus. The base of the foreland deposits has an age of ca. 26 Ma in the western Zagros and 21.5 Ma in the eastern Zagros. We detect the onset of forebulge formation within the Asmari Formation around 25 Ma. Combined with available age constraints across the Zagros, our results show that the unconformity is diachronous and records the southwestward migration of the flexural bulge within the Arabian plate at an average rate of 24±2 mm/yr since the collision. We conclude that closure of the Neo-Tethys formed the Zagros collisional wedge at 27±2 Ma. Hence, the Arabia-Eurasia collision could not be the main driver of global cooling which started near the Eocene-Oligocene boundary (ca. 33.7 Ma). We estimate 650 km of forebulge migration since the onset of the collision which consists of 350 km of shortening across the orogen, and 300 km of widening of the wedge and increasing flexural rigidity of Arabia. The average rate of shortening across the Zagros is estimated to be ca. 13 mm/yr over the last 27 Myr; a value comparable to the modern rate. Palinspastic restoration of structural cross-sections and crustal volume conservation accounts for only ca. 200 km of shortening across the Zagros and metamorphic Sanandaj-Sirjan belt implying that at least 150 km of the Arabian crust was underthrust beneath Eurasia without contributing to crustal thickening, possibly due to eclogitization.

Intentional and automatic processing of numerical information in mathematical anxiety: testing the influence of emotional priming.

PubMed

Ashkenazi, Sarit

2018-02-05

Current theoretical approaches suggest that mathematical anxiety (MA) manifests itself as a weakness in quantity manipulations. This study is the first to examine automatic versus intentional processing of numerical information using the numerical Stroop paradigm in participants with high MA. To manipulate anxiety levels, we combined the numerical Stroop task with an affective priming paradigm. We took a group of college students with high MA and compared their performance to a group of participants with low MA. Under low anxiety conditions (neutral priming), participants with high MA showed relatively intact number processing abilities. However, under high anxiety conditions (mathematical priming), participants with high MA showed (1) higher processing of the non-numerical irrelevant information, which aligns with the theoretical view regarding deficits in selective attention in anxiety and (2) an abnormal numerical distance effect. These results demonstrate that abnormal, basic numerical processing in MA is context related.

Temperature fluctuation of the Iceland mantle plume through time

NASA Astrophysics Data System (ADS)

Spice, Holly E.; Fitton, J. Godfrey; Kirstein, Linda A.

2016-02-01

The newly developed Al-in-olivine geothermometer was used to find the olivine-Cr-spinel crystallization temperatures of a suite of picrites spanning the spatial and temporal extent of the North Atlantic Igneous Province (NAIP), which is widely considered to be the result of a deep-seated mantle plume. Our data confirm that start-up plumes are associated with a pulse of anomalously hot mantle over a large spatial area before becoming focused into a narrow upwelling. We find that the thermal anomaly on both sides of the province at Baffin Island/West Greenland and the British Isles at ˜61 Ma across an area ˜2000 km in diameter was uniform, with Al-in-olivine temperatures up to ˜300°C above that of average mid-ocean ridge basalt (MORB) primitive magma. Furthermore, by combining our results with geochemical data and existing geophysical and bathymetric observations, we present compelling evidence for long-term (>107 year) fluctuations in the temperature of the Iceland mantle plume. We show that the plume temperature fell from its initial high value during the start-up phase to a minimum at about 35 Ma, and that the mantle temperature beneath Iceland is currently increasing.

The Mesozoic Caosiyao giant porphyry Mo deposit in Inner Mongolia, North China and Paleo-Pacific subduction-related magmatism in the northern North China Craton

NASA Astrophysics Data System (ADS)

Wu, Huaying; Zhang, Lianchang; Pirajno, Franco; Shu, Qihai; Zhang, Min; Zhu, Mingtian; Xiang, Peng

2016-09-01

The Caosiyao giant porphyry Mo deposit is located in the Wulanchabu area of Inner Mongolia, within the northern North China Craton (NCC). It contains more than 2385 Mt of ore with an average grade of 0.075% Mo. In the Caosiyao mining district, Mo mineralization occurs mainly in a Mesozoic granite porphyry as disseminations and stockworks, with some Mo distributed in Archean metamorphic rocks and diabase as stockworks and veins. The host granite porphyry is composed of two different phases that can be distinguished based on mineral assemblages and textures: one phase contains large and abundant phenocrysts (coarse-grained), while the other phase is characterized by fewer and smaller phenocrysts (medium-grained). Zircon U-Pb-Hf analyses of the former phase yielded a concordant 206Pb/238U age of 149.8 ± 2.4 Ma with a 206Pb/238U weighted mean age of 149.9 ± 2.4 Ma and εHf(t) values ranging from -12.2 to 18.3, while the latter phase gave a concordant 206Pb/238U age of 149.0 ± 2.2 Ma with a 206Pb/238U weighted mean age of 149.0 ± 2.1 Ma and εHf(t) values ranging from -13.1 to 17.7. Five samples of disseminated molybdenite have a 187Re-187Os isochron age of 149.5 ± 5.3 Ma with a weighted average age of 149.0 ± 1.8 Ma, whereas six veinlet-type molybdenite samples have a well-constrained 187Re-187Os isochron age of 146.9 ± 3.1 Ma and a weighted average age of 146.5 ± 0.8 Ma. Thus, it is suggested that the Mo mineralization of the Caosiyao deposit occurred during the Late Jurassic (ca. 147-149 Ma), almost coeval with the emplacement of the host granite porphyry (ca. 149-150 Ma). The host granite porphyry is characterized by high silica (SiO2 = 71.52-74.10 wt%), relatively high levels of oxidation (Fe2O3/FeO = 0.32-0.94 wt%) and high alkali element concentrations (Na2O + K2O = 8.21-8.76 wt%). The host granite porphyry also shows enrichments in U and K, and depletion in Ba, Sr, P, Eu, and Ti, suggesting strong fractional crystallization of plagioclase, biotite, and accessory minerals. These observations, together with high SiO2 contents and a high differentiation index (DI = 89.04-92.44), indicate a strong differentiation of the granite magma. Based on geological, geochronological, isotope systematics, and geochemical studies, we propose, for the first time, a genetic model for the Caosiyao porphyry Mo deposit. Under a regional extensional setting caused by far-field tectonics related to the Paleo-Pacific subduction during the Late Jurassic, a series of geodynamic, magmatic, and ore-forming processes took place, including formation of multi-directional and multi-phase faults, emplacement of the granitic host rocks, and Mo mineralization. Highly silicic, highly oxidized, and alkali-rich granitic magma, derived from partial melting of old lower crust, intruded into the country rocks. This highly differentiated granitic magma and the exsolved ore-forming fluids, enriched in Mo, migrated upward and interacted with the wall rocks. Eventually, ore minerals precipitated in fractures, resulting in the extensive deposition of molybdenite.

3.1 Ga crystallization age for magnesian and ferroan gabbro lithologies in the Northwest Africa 773 clan of lunar meteorites

NASA Astrophysics Data System (ADS)

Shaulis, B. J.; Righter, M.; Lapen, T. J.; Jolliff, B. L.; Irving, A. J.

2017-09-01

The Northwest Africa (NWA) 773 clan of meteorites is a group of paired and/or petrogenetically related stones that contain at least six different lithologies: magnesian gabbro, ferroan gabbro, anorthositic gabbro, olivine phyric basalt, regolith breccia, and polymict breccia. Uranium-lead dates of baddeleyite in the magnesian gabbro, ferroan gabbro, and components within breccia lithologies of paired lunar meteorites NWA 773, NWA 3170, NWA 6950, and NWA 7007 indicate a chronologic link among the meteorites and their components. A total of 50 baddeleyite grains were analyzed and yielded weighted average 207Pb-206Pb dates of 3119.4 ± 9.4 (n = 27), 3108 ± 20 (n = 13), and 3113 ± 15 (n = 10) Ma for the magnesian gabbro, ferroan gabbro, and polymict breccia lithologies, respectively. A weighted average date of 3115.6 ± 6.8 Ma (n = 47/50) was calculated from the baddeleyite dates for all lithologies. A single large zircon grain found in a lithic clast in the polymict breccia of NWA 773 yielded a U-Pb concordia date of 3953 ± 18 Ma, indicating a much more ancient source for some of the components within the breccia. A U-Pb concordia date of apatite and merrillite grains from the magnesian gabbro and polymict breccia lithologies in NWA 773 is 3112 ± 33 Ma, identical to the baddeleyite dates. Magnesian and ferroan gabbros, as well as the dated baddeleyite and Ca-phosphate-bearing detritus in the breccia lithologies, formed during the same igneous event at about 3115 Ma. These data also strengthen proposed petrogenetic connections between magnesian and ferroan gabbro lithologies, which represent some of the youngest igneous rocks known from the Moon.

Re-Os ages for Archean molybdenite and pyrite, Kuittila-Kivisuo, Finland and Proterozoic molybdenite, Kabeliai, Lithuania: Testing the chronometer in a metamorphic and metasomatic setting

USGS Publications Warehouse

Stein, H.J.; Sundblad, K.; Markey, R.J.; Morgan, J.W.; Motuza, G.

1998-01-01

Seven 187Re-187Os ages were determined for molybdenite and pyrite samples from two well-dated Precambrian intrusions in Fennoscandia to examine the sustainability of the Re-Os chronometer in a metamorphic and metasomatic setting. Using a new 187Re decay constant (1.666 x 10-11y-1) with a much improved uncertainty (±0.31%), we determined replicate Re-Os ages for molybdenite and pyrite from the Kuittila and Kivisuo prospects in easternmost Finland and for molybdenite from the Kabeliai prospect in southernmost Lithuania. These two localities contain some of the oldest and youngest plutonic activity in Fennoscandia and are associated with newly discovered economic Au mineralization (Ilomantsi, Finland) and a Cu-Mo prospect (Kabeliai, Lithuania). Two Re-Os ages for veinhosted Kabeliai molybdenite average 1486 ± 5 Ma, in excellent agreement with a 1505 ± 11 Ma U-Pb zircon age for the hosting Kabeliai granite pluton. The slightly younger age suggests the introduction of Cu-Mo mineralization by a later phase of the Kabeliai magmatic system. Mean Re-Os ages of 2778 ± 8 Ma and 2781 ± 8 Ma for Kuittila and Kivisuo molybdenites, respectively, are in reasonable agreement with a 2753 ± 5 Ma weighted mean U-Pb zircon age for hosting Kuittila tonalite. These Re-Os ages agree well with less precise ages of 2789 ± 290 Ma for a Rb-Sr whole-rock isochron and 2771 ± 75 Ma for the average of six Sm-Nd T(DM) model ages for Kuittila tonalite. Three Re-Os analyses of a single pyrite mineral separate, from the same sample of Kuittila pluton that yielded a molybdenite separate, provide individual model ages of 2710 ± 27, 2777 ± 28, and 2830 ± 28 Ma (Re = 17.4, 12.1, and 8.4 ppb, respectively), with a mean value of 2770 ± 120 Ma in agreement with the Kuittila molybdenite age. The Re and 187Os abundances in these three pyrite splits are highly correlated (r = 0.9994), and provide a 187Re-187Os isochron age of 2607 ± 47 Ma with an intercept of 21 ppt 187Os (MSWD = 1.1). It appears that the Re-Os isotopic system in pyrite has been reset on the millimeter scale and that the 21 ppt 187Os intercept reflects the in situ decay of 187Re during the ~160 to 170 m.y. interval from ~2778 Ma (time of molybdenite ± pyrite deposition) to ~2607 Ma (time of pyrite resetting). When the Re-Os data for molybdenites from the nearby Kivisuo prospect are plotted together with the Kuittila molybdenite and pyrite data, a well-constrained five-point isochron with an age of 2780 ± 8 Ma and a 187Os intercept (-2.4 ± 3.8 ppt) of essentially zero results (MSWD = 1.5). We suggest that the pyrite isochron age records a regional metamorphic and/or hydrothermal event, possibly the time of Au mineralization. A proposed Re-Os age of ~2607 Ma for Au mineralization is in good agreement with radiometric ages by other methods that address the timing of Archean Au mineralization in deposits worldwide (so-called 'late Au model'). Molybdenite, in contrast, provides a robust Re-Os chronometer, retaining its original formation age of ~2780 Ma, despite subsequent metamorphic disturbances in Archean and Proterozoic time.

Ion extraction from a saddle antenna RF surface plasma source

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

Dudnikov, V., E-mail: vadim@muonsinc.com; Johnson, R. P.; Han, B.

Existing RF Surface Plasma Sources (SPS) for accelerators have specific efficiencies for H{sup +} and H{sup −} ion generation around 3 to 5 mA/cm{sup 2} per kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) SPS described here was developed to improve H{sup −} ion production efficiency and SPS reliability and availability. At low RF power, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm{sup 2} per kW of RF power at 13.56 MHz. Initial cesiation of the SPS was performed bymore » heating cesium chromate cartridges by discharge as was done in the very first versions of the SPS. A small oven to decompose cesium compounds and alloys was developed and tested. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA with RF power ∼1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ∼4 kW RF power in the plasma and 250 Gauss longitudinal magnetic field. The ratio of electron current to negative ion current was improved from 30 to 2. Stable generation of H{sup −} beam without intensity degradation was demonstrated in the AlN discharge chamber for a long time at high discharge power in an RF SPS with an external antenna. Continuous wave (CW) operation of the SA SPS has been tested on the small test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. The extracted collector current can be increased significantly by optimizing the longitudinal magnetic field in the discharge chamber. CW operation with negative ion extraction was tested with RF power up to 1.8 kW from the generator (∼1.2 kW in the plasma) with production up to Ic=7 mA. Long term operation was tested with 1.2 kW from the RF generator (∼0.8 kW in the plasma) with production of Ic=5 mA, Iex ∼15 mA (Uex=8 kV, Uc=14 kV)« less

Ion extraction from a saddle antenna RF surface plasma source

NASA Astrophysics Data System (ADS)

Dudnikov, V.; Johnson, R. P.; Han, B.; Murray, S.; Pennisi, T.; Piller, C.; Santana, M.; Stockli, M.; Welton, R.; Breitschopf, J.; Dudnikova, G.

2015-04-01

Existing RF Surface Plasma Sources (SPS) for accelerators have specific efficiencies for H+ and H- ion generation around 3 to 5 mA/cm2 per kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) SPS described here was developed to improve H- ion production efficiency and SPS reliability and availability. At low RF power, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm2 per kW of RF power at 13.56 MHz. Initial cesiation of the SPS was performed by heating cesium chromate cartridges by discharge as was done in the very first versions of the SPS. A small oven to decompose cesium compounds and alloys was developed and tested. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA with RF power ˜1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ˜4 kW RF power in the plasma and 250 Gauss longitudinal magnetic field. The ratio of electron current to negative ion current was improved from 30 to 2. Stable generation of H- beam without intensity degradation was demonstrated in the AlN discharge chamber for a long time at high discharge power in an RF SPS with an external antenna. Continuous wave (CW) operation of the SA SPS has been tested on the small test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. The extracted collector current can be increased significantly by optimizing the longitudinal magnetic field in the discharge chamber. CW operation with negative ion extraction was tested with RF power up to 1.8 kW from the generator (˜1.2 kW in the plasma) with production up to Ic=7 mA. Long term operation was tested with 1.2 kW from the RF generator (˜0.8 kW in the plasma) with production of Ic=5 mA, Iex ˜15 mA (Uex=8 kV, Uc=14 kV).

Stratigraphy, Hydrothermal Alteration and Evolution of the Mangakino Geothermal System, Taupo Volcanic Zone, New Zealand

NASA Astrophysics Data System (ADS)

Fagan, C. J.; Wilson, C. J.; Spinks, K. D.; Browne, P. R.; Simmons, S. F.

2006-12-01

A major part of the ca. 1.6 Myr history of the Taupo Volcanic Zone (TVZ) is represented by buried and hydrothermally altered rocks penetrated by geothermal exploration wells. The geothermal field at Mangakino is sited in the oldest TVZ caldera on the western edge of the TVZ. Four exploration wells into the field reveal a thick sequence of flat-lying ignimbrites. Basement Mesozoic greywacke metasediments were not reached by the deepest well, MA2 (3192 m), implying the presence of a thick caldera infill. Ignimbrites exposed at the surface nearby have distinct mineralogies and crystal contents, which enable correlation with down-hole lithologies. Five ignimbrites are identified in the wells: the 0.32 Ma Whakamaru, 0.93 Ma Marshall, 1.0 Ma Rocky Hill, 1.18 Ma Ahuroa and 1.25 Ma Ongatiti ignimbrites, two of which are >800m thick. The Whakamaru and Marshall units are separated by a thick sequence of lacustrine and volcaniclastic deposits related to infilling of the Mangakino caldera. The ignimbrite sequence is continuous between all wells, with no fault offset, and only well MA3 intersects two rhyolite intrusions at 1190 m and 1850 m that are thought to be feeder dikes to post-0.32 Ma rhyolite domes to the east of Mangakino. Alteration assemblages include epidote and wairakite in MA2 below 2200 m. Adularia occurs in MA2 and MA3 where it replaces, wholly or in part, primary andesine. Adularia is also locally replaced by illite, indicating a shift in hydrothermal conditions. Other minerals present are chlorite, quartz, calcite, titanite and pyrite. Secondary quartz and calcite veins are seen in thin section, with a first appearance in the lacustrine sediments at 550 m in both MA2 and MA3. Fluid inclusions in secondary calcite show high temperatures (300 and 315 °C) while inclusions in primary quartz show ca. 165 °C (the current temperature at the sampled depth), recording current conditions. The modern maximum temperature is 250 °C at 3000 m in MA2. Evidence for two different temperatures in the fluid inclusion data and a shift in alteration mineralogy may reflect an earlier thermal event, possibly related to dike intrusion nearby.

Catalyst engineering for lithium ion batteries: the catalytic role of Ge in enhancing the electrochemical performance of SnO2(GeO2)0.13/G anodes.

PubMed

Zhu, Yun Guang; Wang, Ye; Han, Zhao Jun; Shi, Yumeng; Wong, Jen It; Huang, Zhi Xiang; Ostrikov, Kostya Ken; Yang, Hui Ying

2014-12-21

The catalytic role of germanium (Ge) was investigated to improve the electrochemical performance of tin dioxide grown on graphene (SnO(2)/G) nanocomposites as an anode material of lithium ion batteries (LIBs). Germanium dioxide (GeO(20) and SnO(2) nanoparticles (<10 nm) were uniformly anchored on the graphene sheets via a simple single-step hydrothermal method. The synthesized SnO(2)(GeO(2))0.13/G nanocomposites can deliver a capacity of 1200 mA h g(-1) at a current density of 100 mA g(-1), which is much higher than the traditional theoretical specific capacity of such nanocomposites (∼ 702 mA h g(-1)). More importantly, the SnO(2)(GeO(2))0.13/G nanocomposites exhibited an improved rate, large current capability (885 mA h g(-1) at a discharge current of 2000 mA g(-1)) and excellent long cycling stability (almost 100% retention after 600 cycles). The enhanced electrochemical performance was attributed to the catalytic effect of Ge, which enabled the reversible reaction of metals (Sn and Ge) to metals oxide (SnO(2) and GeO(2)) during the charge/discharge processes. Our demonstrated approach towards nanocomposite catalyst engineering opens new avenues for next-generation high-performance rechargeable Li-ion batteries anode materials.

Relative Motion of the Nazca (farallon) and South American Plates Since Late Cretaceous Time

NASA Astrophysics Data System (ADS)

Pardo-Casas, Federico; Molnar, Peter

1987-06-01

By combining reconstructions of the South American and African plates, the African and Antarctic plates, the Antarctic and Pacific plates, and the Pacific and Nazca plates, we calculated the relative positions and history of convergence of the Nazca and South American plates. Despite variations in convergence rates along the Andes, periods of rapid convergence (averaging more than 100 mm/a) between the times of anomalies 21 (49.5 Ma) and 18 (42 Ma) and since anomaly 7 (26 Ma) coincide with two phases of relatively intense tectonic activity in the Peruvian Andes, known as the late Eocene Incaic and Mio-Pliocene Quechua phases. The periods of relatively slow convergence (50 to 55 ± 30 mm/a at the latitude of Peru and less farther south) between the times of anomalies 30-31 (68.5 Ma) and 21 and between those of anomalies 13 (36 Ma) and 7 correlate with periods during which tectonic activity was relatively quiescent. Thus these reconstructions provide quantitative evidence for a correlation of the intensity of tectonic activity in the overriding plate at subduction zones with variations in the convergence rate.

The Banana Fruit SINA Ubiquitin Ligase MaSINA1 Regulates the Stability of MaICE1 to be Negatively Involved in Cold Stress Response.

PubMed

Fan, Zhong-Qi; Chen, Jian-Ye; Kuang, Jian-Fei; Lu, Wang-Jin; Shan, Wei

2017-01-01

The regulation of ICE1 protein stability is important to ensure effective cold stress response, and is extensively studied in Arabidopsis . Currently, how ICE1 stability in fruits under cold stress is controlled remains largely unknown. Here, we reported the possible involvement of a SEVEN IN ABSENTIA (SINA) ubiquitin ligase MaSINA1 from banana fruit in affecting MaICE1 stability. MaSINA1 was identified based on a yeast two-hybrid screening using MaICE1 as bait. Further yeast two-hybrid, pull-down, bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation (CoIP) assays confirmed that MaSINA1 interacted with MaICE1. The expression of MaSINA1 was repressed by cold stress. Subcellular localization analysis in tobacco leaves showed that MaSINA1 was localized predominantly in the nucleus. In vitro ubiquitination assay showed that MaSINA1 possessed E3 ubiquitin ligase activity. More importantly, in vitro and semi- in vivo experiments indicated that MaSINA1 can ubiquitinate MaICE1 for the 26S proteasome-dependent degradation, and therefore suppressed the transcriptional activation of MaICE1 to MaNAC1, an important regulator of cold stress response of banana fruit. Collectively, our data reveal a mechanism in banana fruit for control of the stability of ICE1 and for the negative regulation of cold stress response by a SINA E3 ligase via the ubiquitin proteasome system.

Fully reversible current driven by a dual marine photosynthetic microbial community.

PubMed

Darus, Libertus; Lu, Yang; Ledezma, Pablo; Keller, Jürg; Freguia, Stefano

2015-11-01

The electrochemical activity of two seawater microbial consortia were investigated in three-electrode bioelectrochemical cells. Two seawater inocula - from the Sunshine Coast (SC) and Gold Coast (GC) shores of Australia - were enriched at +0.6 V vs. SHE using 12/12 h day/night cycles. After re-inoculation, the SC consortium developed a fully-reversible cathodic/anodic current, with a max. of -62 mA m(-2) during the day and +110 mA m(-2) at night, while the GC exhibited negligible daytime output but +98 mA m(-2) at night. Community analysis revealed that both enrichments were dominated by cyanobacteria, indicating their potential as biocatalysts for indirect light conversion to electricity. Moreover, the presence of γ-proteobacterium Congregibacter in SC biofilm was likely related to the cathodic reductive current, indicating its effectiveness at catalysing cathodic oxygen reduction at a surprisingly high potential. For the first time a correlation between a dual microbial community and fully reversible current is reported. Copyright © 2015 Elsevier Ltd. All rights reserved.

Refined beam measurements on the SNS H- injector

NASA Astrophysics Data System (ADS)

Han, B. X.; Welton, R. F.; Murray, S. N.; Pennisi, T. R.; Santana, M.; Stinson, C. M.; Stockli, M. P.

2017-08-01

The H- injector for the SNS RFQ accelerator consists of an RF-driven, Cs-enhanced H- ion source and a compact, two-lens electrostatic LEBT. The LEBT output and the RFQ input beam current are measured by deflecting the beam on to an annular plate at the RFQ entrance. Our method and procedure have recently been refined to improve the measurement reliability and accuracy. The new measurements suggest that earlier measurements tended to underestimate the currents by 0-2 mA, but essentially confirm H- beam currents of 50-60 mA being injected into the RFQ. Emittance measurements conducted on a test stand featuring essentially the same H- injector setup show that the normalized rms emittance with 0.5% threshold (99% inclusion of the total beam) is in a range of 0.25-0.4 mm.mrad for a 50-60 mA beam. The RFQ output current is monitored with a BCM toroid. Measurements as well as simulations with the PARMTEQ code indicate an underperforming transmission of the RFQ since around 2012.

Next Generation H- Ion Sources for the SNS

NASA Astrophysics Data System (ADS)

Welton, R. F.; Stockli, M. P.; Murray, S. N.; Crisp, D.; Carmichael, J.; Goulding, R. H.; Han, B.; Tarvainen, O.; Pennisi, T.; Santana, M.

2009-03-01

The U.S. Spallation Neutron Source (SNS) is the leading accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to insure meeting operational requirements as well as providing for future facility beam power upgrades, a multifaceted H- ion source development program is ongoing. This work discusses several aspects of this program, specifically the design and first beam measurements of an RF-driven, external antenna H- ion source based on an A1N ceramic plasma chamber, elemental and chromate Cs-systems, and plasma ignition gun. Unanalyzed beam currents of up to ˜100 mA (60 Hz, 1 ms) have been observed and sustained currents >60 mA (60 Hz, 1 ms) have been demonstrated on the test stand. Accelerated beam currents of ˜40 mA have also been demonstrated into the SNS front end. Data are also presented describing the first H- beam extraction experiments from a helicon plasma generator based on the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) engine design.

Light scatter on the surface of AcrySof intraocular lenses: part I. Analysis of lenses retrieved from pseudophakic postmortem human eyes.

PubMed

Yaguchi, Shigeo; Nishihara, Hitoshi; Kambhiranond, Waraporn; Stanley, Daniel; Apple, David J

2008-01-01

To investigate the cause of light scatter measured on the surface of AcrySof intraocular lenses (Alcon Laboratories, Inc., Fort Worth, TX) retrieved from pseudophakic postmortem human eyes. Ten intraocular lenses (Alcon AcrySofModel MA60BM) were retrieved postmortem and analyzed for light scatter before and after removal of surface-bound biofilms. Six of the 10 lenses exhibited light scatter that was clearly above baseline levels. In these 6 lenses, both peak and average pixel density were reduced by approximately 80% after surface cleaning. The current study demonstrates that a coating deposited in vivo on the lens surface is responsible for the light scatter observed when incident light is applied.

Simulations of Field-Emission Electron Beams from CNT Cathodes in RF Photoinjectors

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

Mihalcea, Daniel; Faillace, Luigi; Panuganti, Harsha

2015-06-01

Average field emission currents of up to 700 mA were produced by Carbon Nano Tube (CNT) cathodes in a 1.3 GHz RF gun at Fermilab High Brightness Electron Source Lab. (HBESL). The CNT cathodes were manufactured at Xintek and tested under DC conditions at RadiaBeam. The electron beam intensity as well as the other beam properties are directly related to the time-dependent electric field at the cathode and the geometry of the RF gun. This report focuses on simulations of the electron beam generated through field-emission and the results are compared with experimental measurements. These simulations were performed with themore » time-dependent Particle In Cell (PIC) code WARP.« less

Feedback process responsible for the suppression of ENSO activity during the mid-Holocene

NASA Astrophysics Data System (ADS)

An, Soon-Il; Bong, Hayoung

2018-05-01

Using the output of 12 models from the Paleoclimate Modeling Intercomparison Project Phase 3, we investigate the feedback process responsible for changes in El Niño-Southern Oscillation activity during the mid-Holocene based on a linear stability index (Bjerknes stability index; BJ index) analysis. The multi-model ensemble mean (MME) variance of the Niño-3.4 index (sea surface temperature anomalies averaged over 5°S-5°N, 170°-120°W) simulated for 6000 years ago (6 kya) was 13% lower than that for the pre-industrial era (0 kya), while changes in the MME BJ index were negligible. This is due to a balance between enhanced damping by anomalous thermal advection by mean currents (MA) and enhanced positive thermocline feedback (TH). Seven of the models show that MME variance of the Niño-3.4 and BJ indexes for the 6 kya run is 21 and 70% lower, respectively, than the 0 kya run. However, two models show the opposite change. Interestingly, MA in both model groups increases, especially due to the mean meridional current associated with enhanced trade winds, indicating a robust mechanism. The opposite tendency between the two groups is mainly due to large TH in the second group 6 kya, as a result of enhanced air-sea coupling and strongly reduced ocean stratification due to subsurface warming, which led to increased sensitivity of the zonal thermocline contrast to surface zonal wind stress.

Three-dimensional magnetohydrodynamic equilibrium of quiescent H-modes in tokamak systems

NASA Astrophysics Data System (ADS)

Cooper, W. A.; Graves, J. P.; Duval, B. P.; Sauter, O.; Faustin, J. M.; Kleiner, A.; Lanthaler, S.; Patten, H.; Raghunathan, M.; Tran, T.-M.; Chapman, I. T.; Ham, C. J.

2016-06-01

Three dimensional free boundary magnetohydrodynamic equilibria that recover saturated ideal kink/peeling structures are obtained numerically. Simulations that model the JET tokamak at fixed < β > =1.7% with a large edge bootstrap current that flattens the q-profile near the plasma boundary demonstrate that a radial parallel current density ribbon with a dominant m /n  =  5/1 Fourier component at {{I}\\text{t}}=2.2 MA develops into a broadband spectrum when the toroidal current I t is increased to 2.5 MA.

Synthesis and Characterization of Types A and B Gelatin Methacryloyl for Bioink Applications

PubMed Central

Lee, Bae Hoon; Lum, Nathaniel; Seow, Li Yuan; Lim, Pei Qi; Tan, Lay Poh

2016-01-01

Gelatin methacryloyl (GelMA) has been increasingly considered as an important bioink material due to its tailorable mechanical properties, good biocompatibility, and ability to be photopolymerized in situ as well as printability. GelMA can be classified into two types: type A GelMA (a product from acid treatment) and type B GelMA (a product from alkali treatment). In current literature, there is little research on the comparison of type A GelMA and type B GelMA in terms of synthesis, rheological properties, and printability for bioink applications. Here, we report the synthesis, rheological properties, and printability of types A and B GelMA. Types A and B GelMA samples with different degrees of substitution (DS) were prepared in a controllable manner by a time-lapse loading method of methacrylic anhydride (MAA) and different feed ratios of MAA to gelatin. Type B GelMA tended to have a slightly higher DS compared to type A GelMA, especially in a lower feed ratio of MAA to gelatin. All the type A and type B GelMA solutions with different DS exhibited shear thinning behaviours at 37 °C. However, only GelMA with a high DS had an easy-to-extrude feature at room temperature. The cell-laden printed constructs of types A and B GelMA at 20% w/v showed around 75% cell viability. PMID:28773918

Characterization and Performance of a High-Current-Density Ion Implanter with Magnetized Hollow-Cathode Plasma Source

NASA Astrophysics Data System (ADS)

Falkenstein, Zoran; Rej, Donald; Gavrilov, Nikolai

1998-10-01

In a collaboration between the Institute of Electrophysics (IEP) and the Los Alamos National Laboratory (LANL), the IEP has developed an industrial scalable, high-power, large-area ion source for the surface modification of materials. The plasma source of the ion beam source can be described as a pulsed glow discharge with a cold, hollow-cathode in a weak magnetic field. Extraction and focusing of positive ions by an acceleration and ion-optical plate system renders the generation of a homogeneous, large-area ion beam with an averaged total ion current of up to 50 mA at acceleration voltages of up to 50 kV. The principle set-up of the ion beam source as well as some electrical characteristics (gas discharge current and the extracted ion beam current) are presented for a lab-scale prototype. Measurements of the radial ion current density profiles within the ion beam for various discharge parameters, as well as results on surface modification by ion implantation of nitrogen into aluminum and chromium are presented. Finally, a comparison of the applied ion dose with the retained ion doses is given.

Pharmaceutical Market Access: current state of affairs and key challenges – results of the Market Access Launch Excellence Inventory (MALEI)

PubMed Central

Koch, Marcus A.

2015-01-01

Objectives To take inventory of the current state of affairs of Market Access Launch Excellence in the life sciences industry. To identify key gaps and challenges for Market Access (MA) and discuss how they can be addressed. To generate a baseline for benchmarking MA launch excellence. Methodology An online survey was conducted with pharmaceutical executives primarily working in MA, marketing, or general management. The survey aimed to evaluate MA excellence prerequisites across the product life cycle (rated by importance and level of implementation) and to describe MA activity models in the respective companies. Composite scores were calculated from respondents’ ratings and answers. Results Implementation levels of MA excellence prerequisites generally lagged behind their perceived importance. Item importance and the respective level of implementation correlated well, which can be interpreted as proof of the validity of the questionnaire. The following areas were shown to be particularly underimplemented: 1) early integration of MA and health economic considerations in research and development decision making, 2) developing true partnerships with payers, including the development of services ‘beyond the pill’, and 3) consideration of human resource and talent management. The concept of importance-adjusted implementation levels as a hybrid parameter was introduced and shown to be a viable tool for benchmarking purposes. More than 70% of respondents indicated that their companies will invest broadly in MA in terms of capital and headcount within the next 3 years. Conclusions MA (launch) excellence needs to be further developed in order to close implementation gaps across the entire product life cycle. As MA is a comparatively young pharmaceutical discipline in a complex and dynamic environment, this effort will require strategic focus and dedication. The Market Access Launch Excellence Inventory benchmarking tool may help guide decision makers to prioritize their endeavors. PMID:29785250

Provenance history of detrital diamond deposits, West Coast of Namaqualand, South Africa

NASA Astrophysics Data System (ADS)

Phillips, David; Harris, Jeffrey W.; de Wit, Michiel C. J.; Matchan, Erin L.

2018-05-01

The West Coast of Namaqualand in South Africa hosts extensive detrital diamond deposits, but considerable debate exists as to the provenance of these diamonds. Some researchers have suggested derivation of the diamonds from Cretaceous-Jurassic kimberlites (also termed Group I kimberlites) and orangeites (also termed Group II kimberlites) located on the Kaapvaal Craton. However, others favour erosion of diamonds from the ca.300 Ma Dwyka Group sediments, with older, pre-Karoo kimberlites being the original source(s). Previous work has demonstrated that 40Ar/39Ar analyses of clinopyroxene inclusions, extracted from diamonds, yield ages approaching the time(s) of source kimberlite emplacement, which can be used to constrain the provenance of placer diamond deposits. In the current study, 40Ar/39Ar analyses were conducted on clinopyroxene inclusions from two similar batches of Namaqualand detrital diamonds, yielding (maximum) ages ranging from 117.5 ± 43.6 Ma to 3684 ± 191 Ma (2σ) and 120.6 ± 15.4 Ma to 688.8 ± 4.9 Ma (2σ), respectively. The vast majority of inclusions (88%) produced ages younger than 500 Ma, indicating that most Namaqualand diamonds originated from Cretaceous-Jurassic kimberlites/orangeites, with few, if any, derived from the Dwyka tillites. The provenance of the Namaqualand diamonds from ca.115-200 Ma orangeites is consistent with Late Cretaceous paleo-drainage reconstructions, as these localities could have been sampled by the `paleo-Karoo' River and transported to the West Coast via an outlet close to the current Olifants River mouth. At ca.90 Ma, this drainage system appears to have been captured by the `paleo-Kalahari' River, a precursor to the modern Orange River system. This latter drainage is considered to have transported diamonds eroded from both ca.80-90 Ma kimberlites and ca.115-200 Ma orangeites to the West Coast, which were subsequently reworked along the Namibian coast, forming additional placer deposits.

An Evaluation of the Evidence that Methamphetamine Abuse Causes Cognitive Decline in Humans

PubMed Central

Dean, Andy C; Groman, Stephanie M; Morales, Angelica M; London, Edythe D

2013-01-01

Methamphetamine (MA) is one of the most commonly abused illicit substances worldwide. Among other problems, abuse of the drug has been associated with reduced cognitive function across several domains. However, much of the literature has not attempted to differentiate cognitive difficulties caused by MA abuse from preexisting cognitive difficulties that are likely caused by other factors. Here, we address this question, evaluating evidence for a priori hypotheses pertaining to six lines of research: (a) animal studies; (b) cross-sectional human studies; (c) a twin study; (d) studies of changes in cognition with abstinence from MA; (e) studies of changes in brain structure and function with abstinence from MA; and (f) studies of the relationship between the severity of MA abuse and the extent of cognitive deficits observed. Overall the findings were mixed, with some support for a causal relationship between MA abuse and cognitive decline, and other findings suggesting that there is no relationship. The preponderance of the data, however, does support the possibility that MA abuse causes cognitive decline, of unknown duration, in at least some users of the drug. When averaged across individuals, this decline is likely to be mild in early-to-middle adulthood. However, moderator variables are likely to contribute to the presence and/or severity of cognitive decline exhibited by a given individual. PMID:22948978

MaNGA: Mapping Nearby Galaxies at Apache Point Observatory

NASA Astrophysics Data System (ADS)

Weijmans, A.-M.; MaNGA Team

2016-10-01

MaNGA (Mapping Nearby Galaxies at APO) is a galaxy integral-field spectroscopic survey within the fourth generation Sloan Digital Sky Survey (SDSS-IV). It will be mapping the composition and kinematics of gas and stars in 10,000 nearby galaxies, using 17 differently sized fiber bundles. MaNGA's goal is to provide new insights in galaxy formation and evolution, and to deliver a local benchmark for current and future high-redshift studies.

Profitability of simple technical trading rules of Chinese stock exchange indexes

NASA Astrophysics Data System (ADS)

Zhu, Hong; Jiang, Zhi-Qiang; Li, Sai-Ping; Zhou, Wei-Xing

2015-12-01

Although technical trading rules have been widely used by practitioners in financial markets, their profitability still remains controversial. We here investigate the profitability of moving average (MA) and trading range break (TRB) rules by using the Shanghai Stock Exchange Composite Index (SHCI) from May 21, 1992 through December 31, 2013 and Shenzhen Stock Exchange Component Index (SZCI) from April 3, 1991 through December 31, 2013. The t-test is adopted to check whether the mean returns which are conditioned on the trading signals are significantly different from unconditioned returns and whether the mean returns conditioned on the buy signals are significantly different from the mean returns conditioned on the sell signals. We find that TRB rules outperform MA rules and short-term variable moving average (VMA) rules outperform long-term VMA rules. By applying White's Reality Check test and accounting for the data snooping effects, we find that the best trading rule outperforms the buy-and-hold strategy when transaction costs are not taken into consideration. Once transaction costs are included, trading profits will be eliminated completely. Our analysis suggests that simple trading rules like MA and TRB cannot beat the standard buy-and-hold strategy for the Chinese stock exchange indexes.

The 300 mA SRF ERL

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

Ben-Zvi, Ilan

Energy Recovery Linacs (ERL) are important for a variety of applications, from high-power Free-Electron Lasers (FEL) to polarized-electron polarized-proton colliders. The ERL current is arguably the most important characteristic of ERLs for such applications. With that in mind, the Collider-Accelerator Department at Brookhaven National Laboratory embarked on the development of a 300 mA ERL to serve as an R and D test-bed for high-current ERL technologies. These include high-current, extremely well damped superconducting accelerating cavities, high-current superconducting laser-photocathode electron guns and high quantum-efficiency photocathodes. In this presentation I will cover these ERL related developments.

Ultralow-quiescent-current and wide-load-range low-dropout linear regulator with self-biasing technique for micropower battery management

NASA Astrophysics Data System (ADS)

Ozaki, Toshihiro; Hirose, Tetsuya; Asano, Hiroki; Kuroki, Nobutaka; Numa, Masahiro

2017-04-01

In this paper, we present a 151 nA quiescent and 6.8 mA maximum-output-current low-dropout (LDO) linear regulator for micropower battery management. The LDO regulator employs self-biasing and multiple-stacked cascode techniques to achieve efficient, accurate, and high-voltage-input-tolerant operation. Measurement results demonstrated that the proposed LDO regulator operates with an ultralow quiescent current of 151 nA. The maximum output currents with a 4.16 V output were 1.0 and 6.8 mA when the input voltages were 4.25 and 5.0 V, respectively.

Chemical composition and biological activity of star anise Illicium verum extracts against maize weevil, Sitophilus zeamais adults

PubMed Central

Wei, Linlin; Hua, Rimao; Li, Maoye; Huang, Yanzhang; Li, Shiguang; He, Yujie; Shen, Zonghai

2014-01-01

Abstract This study aims to develop eco-friendly botanical pesticides. Dried fruits of star anise ( Illicium verum Hook.f. (Austrobaileyales: Schisandraceae)) were extracted with methyl alcohol (MA), ethyl acetate (EA), and petroleum ether (PE) at 25°C. The constituents were determined by gas chromatography-mass spectrometry, and the repellency and contact toxicity of the extracts against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) adults were tested. Forty-four compounds, whose concentrations were more than 0.2%, were separated and identified from the MA, EA, and PE extracts. The extraction yields of trans-anethole, the most abundant biologically active compound in I. verum , were 9.7%, 7.5%, and 10.1% in the MA, EA, and PE extracts, respectively. Repellency increased with increasing extract dose. The average repellency rate of the extracts against S. zeamais adults peaked at 125.79 µg/cm 2 72 hr after treatment. The percentage repellency of the EA extract reached 76.9%, making it a class IV repellent. Contact toxicity assays showed average mortalities of 85.4% (MA), 94.5% (EA), and 91.1% (PE). The EA extract had the lowest median lethal dose, at 21.2 µg/cm 2 72 hr after treatment. The results suggest that I. verum fruit extracts and trans-anethole can potentially be developed as a grain protectant to control stored-product insect pests. Other active constituents in the EA extract merit further research. PMID:25368036

Palaeointensity determinations, palaeodirections and magnetic properties of basalts from the Emperor seamounts

NASA Astrophysics Data System (ADS)

Carvallo, Claire; Özdemir, Özden; Dunlop, David J.

2004-01-01

We measured palaeodirections and palaeointensities by the Thellier method on 93 samples from three of the Emperor seamounts: 20 from Detroit seamount (81 Ma), 48 from Nintoku seamount (56 Ma) and 25 from Koko seamount (48 Ma). Reliable palaeodirections obtained from three lava flows on Nintoku seamount give an average palaeolatitude of 32.7°, which is different from the present-day latitude of Hawaii and supports the hypothesis of a moving hotspot. According to the selection criteria traditionally used in palaeointensity determination, 17 samples give a reliable result. The samples show a very wide variety in unblocking temperatures, revealing an important variation in titanium content and the oxidation state of titanomagnetites. In order to assess the reliability of the palaeofield recording in the accepted samples, we carried out measurements of saturation isothermal remanent magnetization at low temperature and thermomagnetic curves. We found Curie temperatures varying from 250 to 580 °C, not only between seamounts but even within one lava flow. Thermomagnetic curves enabled us to identify titanomaghemite in several lava flows. After rejecting the results from samples showing evidence of maghemitization, only four samples, all from Nintoku seamount, can be considered as truly reliable. The palaeointensity values range between 34.2 and 36.9 μT. The low virtual axial dipole moment (VADM) values calculated from the palaeofield values are consistent with the most reliable VADM estimates in this time range and they are very close to the average VADM in the 0.3-300 Ma time interval.

Implications of Pulser Voltage Ripple

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

Barnard, J J

In a recent set of measurements obtained by G. Kamin, W. Manning, A. Molvik, and J. Sullivan, the voltage waveform of the diode pulser had a ripple of approximately {+-}1.3% of the 65 kV flattop voltage, and the beam current had a larger corresponding ripple of approximately {+-}8.4% of the 1.5 mA average current at the location of the second Faraday cup, approximately 1.9 m downstream from the ion source. The period of the ripple was about 1 {mu}s. It was initially unclear whether this large current ripple was in fact a true measurement of the current or a spuriousmore » measurement of noise produced by the pulser electronics. The purpose of this note is to provide simulations which closely match the experimental results and thereby corroborate the physical nature of those measurements, and to provide predictions of the amplitude of the current ripples as they propagate to the end of linear transport section. Additionally analytic estimates are obtained which lend some insight into the nature of the current fluctuations and to provide an estimate of what the maximum amplitude of the current fluctuations are expected to be, and conversely what initial ripple in the voltage source is allowed, given a smaller acceptable tolerance on the line charge density.« less

Central-peripheral neural network interactions evoked by vagus nerve stimulation: functional consequences on control of cardiac function.

PubMed

Ardell, Jeffrey L; Rajendran, Pradeep S; Nier, Heath A; KenKnight, Bruce H; Armour, J Andrew

2015-11-15

Using vagus nerve stimulation (VNS), we sought to determine the contribution of vagal afferents to efferent control of cardiac function. In anesthetized dogs, the right and left cervical vagosympathetic trunks were stimulated in the intact state, following ipsilateral or contralateral vagus nerve transection (VNTx), and then following bilateral VNTx. Stimulations were performed at currents from 0.25 to 4.0 mA, frequencies from 2 to 30 Hz, and a 500-μs pulse width. Right or left VNS evoked significantly greater current- and frequency-dependent suppression of chronotropic, inotropic, and lusitropic function subsequent to sequential VNTx. Bradycardia threshold was defined as the current first required for a 5% decrease in heart rate. The threshold for the right vs. left vagus-induced bradycardia in the intact state (2.91 ± 0.18 and 3.47 ± 0.20 mA, respectively) decreased significantly with right VNTx (1.69 ± 0.17 mA for right and 3.04 ± 0.27 mA for left) and decreased further following bilateral VNTx (1.29 ± 0.16 mA for right and 1.74 ± 0.19 mA for left). Similar effects were observed following left VNTx. The thresholds for afferent-mediated effects on cardiac parameters were 0.62 ± 0.04 and 0.65 ± 0.06 mA with right and left VNS, respectively, and were reflected primarily as augmentation. Afferent-mediated tachycardias were maintained following β-blockade but were eliminated by VNTx. The increased effectiveness and decrease in bradycardia threshold with sequential VNTx suggest that 1) vagal afferents inhibit centrally mediated parasympathetic efferent outflow and 2) the ipsilateral and contralateral vagi exert a substantial buffering capacity. The intact threshold reflects the interaction between multiple levels of the cardiac neural hierarchy. Copyright © 2015 the American Physiological Society.

Central-peripheral neural network interactions evoked by vagus nerve stimulation: functional consequences on control of cardiac function

PubMed Central

Rajendran, Pradeep S.; Nier, Heath A.; KenKnight, Bruce H.; Armour, J. Andrew

2015-01-01

Using vagus nerve stimulation (VNS), we sought to determine the contribution of vagal afferents to efferent control of cardiac function. In anesthetized dogs, the right and left cervical vagosympathetic trunks were stimulated in the intact state, following ipsilateral or contralateral vagus nerve transection (VNTx), and then following bilateral VNTx. Stimulations were performed at currents from 0.25 to 4.0 mA, frequencies from 2 to 30 Hz, and a 500-μs pulse width. Right or left VNS evoked significantly greater current- and frequency-dependent suppression of chronotropic, inotropic, and lusitropic function subsequent to sequential VNTx. Bradycardia threshold was defined as the current first required for a 5% decrease in heart rate. The threshold for the right vs. left vagus-induced bradycardia in the intact state (2.91 ± 0.18 and 3.47 ± 0.20 mA, respectively) decreased significantly with right VNTx (1.69 ± 0.17 mA for right and 3.04 ± 0.27 mA for left) and decreased further following bilateral VNTx (1.29 ± 0.16 mA for right and 1.74 ± 0.19 mA for left). Similar effects were observed following left VNTx. The thresholds for afferent-mediated effects on cardiac parameters were 0.62 ± 0.04 and 0.65 ± 0.06 mA with right and left VNS, respectively, and were reflected primarily as augmentation. Afferent-mediated tachycardias were maintained following β-blockade but were eliminated by VNTx. The increased effectiveness and decrease in bradycardia threshold with sequential VNTx suggest that 1) vagal afferents inhibit centrally mediated parasympathetic efferent outflow and 2) the ipsilateral and contralateral vagi exert a substantial buffering capacity. The intact threshold reflects the interaction between multiple levels of the cardiac neural hierarchy. PMID:26371171

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

Duan, X; Grimes, J; Yu, L

Purpose: Focal spot blooming is an increase in the focal spot size at increased tube current and/or decreased tube potential. In this work, we evaluated the influence of tube current on the focal spot size at low kV for two CT systems, one of which used a tube designed to reduce blooming effects. Methods: A slit camera (10 micron slit) was used to measure focal spot size on two CT scanners from the same manufacturer (Siemens Somatom Force and Definition Flash) at 70 kV and low, medium and maximum tube currents, according to the capabilities of each system (Force: 100,more » 800 and 1300 mA; Flash: 100, 200 and 500 mA). Exposures were made with a stationary tube in service mode using a raised stand without table movement or flying focal spot technique. Focal spot size, nominally 0.8 and 1.2 mm, respectively, was measured parallel and perpendicular to the cathode-anode axis by calculating the full-width-at-half-maximum of the slit profile recording using computed radiographic plates. Results: Focal spot sizes perpendicular to the anode-cathode axis increased at the maximum mA by 5.7% on the Force and 39.1% on the Flash relative to that at the minimal mA, even though the mA was increased 13-fold on the Force and only 5- fold on the Flash. Focal spot size increased parallel to the anode-cathode axis by 70.4% on Force and 40.9% on Flash. Conclusion: For CT protocols using low kV, high mA is typically required. These protocols are relevant in children and smaller adults, and for dual-energy scanning. Technical measures to limit focal spot blooming are important in these settings to avoid reduced spatial resolution. The x-ray tube on a recently-introduced scanner appears to greatly reduce blooming effects, even at very high mA values. CHM has research support from Siemens Healthcare.« less

Transportation properties of a high-current magnetically insulated transmission line and dynamics of the electrode plasma

NASA Astrophysics Data System (ADS)

Anan'ev, S. S.; Bakshaev, Yu. L.; Bartov, A. V.; Blinov, P. I.; Dan'ko, S. A.; Zhuzhunashvili, A. I.; Kazakov, E. D.; Kalinin, Yu. G.; Kingsep, A. S.; Korolev, V. D.; Mizhiritskii, V. I.; Smirnov, V. P.; Tkachenko, S. I.; Chernenko, A. S.

2008-07-01

Results are presented from experimental studies of a section of a magnetically insulated transmission line (MITL) with a current density of up to 500 MA/cm2 and linear current density of up to 7 MA/cm (the parameters close to those in a fast-Z-pinch-driven fusion reactor projected at Sandia Laboratories). The experiments were performed in the S-300 facility (3 MA, 0.15 Ω, 100 ns). At high linear current densities, the surface of the ohmically heated MITL electrode can explode and a plasma layer can form near the electrode surface. As a result, the MITL can lose its transmission properties due to the shunting of the vacuum gap by the plasma produced. In this series of experiments, the dynamics of the electrode plasma and the dependence of the transmission properties of the MITL on the material and cleanness of the electrode surface were studied. It is shown experimentally that, when the current with a linear density of up to 7 MA/cm begins to flow along a model MITL, the input and output currents differ by less than 10% over a time interval of up to 230 ns for nickel electrodes and up to 350 ns for a line with a gold central electrode. No effect of the oil film present on the electrode surface on the loss of the transmission properties of the line was observed. It is also shown that electron losses insignificantly contribute to the total current balance. The experimental results are compared with calculations of the electrode explosion and the subsequent expansion of the plasma layer. A conclusion is made that the life-time of the model MITL satisfies the requirements imposed on the transmission lines intended for use in the projected thermonuclear reactor.

The Cretaceous Okhotsk-Chukotka Volcanic Belt (NE Russia): Geology, geochronology, magma output rates, and implications on the genesis of silicic LIPs

NASA Astrophysics Data System (ADS)

Tikhomirov, P. L.; Kalinina, E. A.; Moriguti, T.; Makishima, A.; Kobayashi, K.; Cherepanova, I. Yu.; Nakamura, E.

2012-04-01

The Cretaceous Okhotsk-Chukotka volcanic belt (OCVB) is a prominent subduction-related magmatic province, having the remarkably high proportion of silicic rocks (ca. 53% of the present-day crop area, and presumably over 70% of the total volcanic volume). Its estimated total extrusive volume ranges between 5.5 × 105 km3 (the most conservative estimate) and over 106 km3. This article presents a brief outline of the geology of OCVB, yet poorly described in international scientific literature, and results of a geochronological study on the northern part of the volcanic belt. On the base of new and published U-Pb and 40Ar/39Ar age determinations, a new chronological model is proposed. Our study indicates that the activity of the volcanic belt was highly discontinuous and comprised at least five main episodes at 106-98 Ma, 94-91 Ma, 89-87 Ma, 85.5-84 Ma, and 82-79 Ma. The new data allow a semi-quantitative estimate of the volcanic output rate for the observed part of the OCVB (area and volume approximately 105 km2 and 2.5 × 105 km3, respectively). The average extrusion rate for the entire lifetime of the volcanic belt ranges between 1.6 and 3.6 × 10- 5 km3yr- 1 km- 1, depending on the assumed average thickness of the volcanic pile; the optimal value is 2.6 × 10- 5 km3yr- 1 km- 1. Despite imprecise, such estimates infer the time-averaged volcanic productivity of the OCVB is similar to that of silicic LIPs and most active recent subduction-related volcanic areas of the Earth. However, the most extensive volcanic flare-ups at 89-87 and 85.5-84 Ma had higher rates of over 9.0 × 10- 5 km3yr- 1 km- 1. The main volumetric, temporal and compositional parameters of the OCVB are similar to those of silicic LIPs. This gives ground for discussion about the geodynamic setting of the latters, because the widely accepted definition of a LIP implies a strictly intraplate environment. Considering the genesis of the OCVB and other large provinces of silicic volcanism, we propose that residual thermal energy preserved in the continental crust after a previous major magmatic event may have been one of major reasons for high proportion of felsic rocks in a volcanic pile. In this scenario, underplating of mantle-derived basalts causes fast and extensive melting of still hot continental crust and generation of voluminous silicic magmas.

Age of Izu-Bonin-Mariana arc basement

NASA Astrophysics Data System (ADS)

Ishizuka, Osamu; Hickey-Vargas, Rosemary; Arculus, Richard J.; Yogodzinski, Gene M.; Savov, Ivan P.; Kusano, Yuki; McCarthy, Anders; Brandl, Philipp A.; Sudo, Masafumi

2018-01-01

Documenting the early tectonic and magmatic evolution of the Izu-Bonin-Mariana (IBM) arc system in the Western Pacific is critical for understanding the process and cause of subduction initiation along the current convergent margin between the Pacific and Philippine Sea plates. Forearc igneous sections provide firm evidence for seafloor spreading at the time of subduction initiation (52 Ma) and production of "forearc basalt". Ocean floor drilling (International Ocean Discovery Program Expedition 351) recovered basement-forming, low-Ti tholeiitic basalt crust formed shortly after subduction initiation but distal from the convergent margin (nominally reararc) of the future IBM arc (Amami Sankaku Basin: ASB). Radiometric dating of this basement gives an age range (49.3-46.8 Ma with a weighted average of 48.7 Ma) that overlaps that of basalt in the present-day IBM forearc, but up to 3.3 m.y. younger than the onset of forearc basalt activity. Similarity in age range and geochemical character between the reararc and forearc basalts implies that the ocean crust newly formed by seafloor spreading during subduction initiation extends from fore- to reararc of the present-day IBM arc. Given the age difference between the oldest forearc basalt and the ASB crust, asymmetric spreading caused by ridge migration might have taken place. This scenario for the formation of the ASB implies that the Mesozoic remnant arc terrane of the Daito Ridges comprised the overriding plate at subduction initiation. The juxtaposition of a relatively buoyant remnant arc terrane adjacent to an oceanic plate was more favourable for subduction initiation than would have been the case if both downgoing and overriding plates had been oceanic.

Lung nodule detection in pediatric chest CT: quantitative relationship between image quality and radiologist performance.

PubMed

Li, Xiang; Samei, Ehsan; Barnhart, Huiman X; Gaca, Ana Maria; Hollingsworth, Caroline L; Maxfield, Charles M; Carrico, Caroline W T; Colsher, James G; Frush, Donald P

2011-05-01

To determine the quantitative relationship between image quality and radiologist performance in detecting small lung nodules in pediatric CT. The study included clinical chest CT images of 30 pediatric patients (0-16 years) scanned at tube currents of 55-180 mA. Calibrated noise addition software was used to simulate cases at three nominal mA settings: 70, 35, and 17.5 mA, resulting in quantum noise of 7-32 Hounsfield Unit (HU). Using a validated nodule simulation technique, lung nodules with diameters of 3-5 mm and peak contrasts of 200-500 HU were inserted into the cases, which were then randomized and rated independently by four experienced pediatric radiologists for nodule presence on a continuous scale from 0 (definitely absent) to 100 (definitely present). The receiver operating characteristic (ROC) data were analyzed to quantify the relationship between diagnostic accuracy (area under the ROC curve, AUC) and image quality (the product of nodule peak contrast and displayed diameter to noise ratio, CDNR display). AUC increased rapidly from 0.70 to 0.87 when CDNR display increased from 60 to 130 mm, followed by a slow increase to 0.94 when CDNR display further increased to 257 mm. For the average nodule diameter (4 mm) and contrast (350 HU), AUC decreased from 0.93 to 0.71 with noise increased from 7 to 28 HU. We quantified the relationship between image quality and the performance of radiologists in detecting lung nodules in pediatric CT. The relationship can guide CT protocol design to achieve the desired diagnostic performance at the lowest radiation dose.

Assessment of phase based dose modulation for improved dose efficiency in cardiac CT on an anthropomorphic motion phantom

NASA Astrophysics Data System (ADS)

Budde, Adam; Nilsen, Roy; Nett, Brian

2014-03-01

State of the art automatic exposure control modulates the tube current across view angle and Z based on patient anatomy for use in axial full scan reconstructions. Cardiac CT, however, uses a fundamentally different image reconstruction that applies a temporal weighting to reduce motion artifacts. This paper describes a phase based mA modulation that goes beyond axial and ECG modulation; it uses knowledge of the temporal view weighting applied within the reconstruction algorithm to improve dose efficiency in cardiac CT scanning. Using physical phantoms and synthetic noise emulation, we measure how knowledge of sinogram temporal weighting and the prescribed cardiac phase can be used to improve dose efficiency. First, we validated that a synthetic CT noise emulation method produced realistic image noise. Next, we used the CT noise emulation method to simulate mA modulation on scans of a physical anthropomorphic phantom where a motion profile corresponding to a heart rate of 60 beats per minute was used. The CT noise emulation method matched noise to lower dose scans across the image within 1.5% relative error. Using this noise emulation method to simulate modulating the mA while keeping the total dose constant, the image variance was reduced by an average of 11.9% on a scan with 50 msec padding, demonstrating improved dose efficiency. Radiation dose reduction in cardiac CT can be achieved while maintaining the same level of image noise through phase based dose modulation that incorporates knowledge of the cardiac reconstruction algorithm.

Mass-production of highly-crystalline few-layer graphene sheets by arc discharge in various H2-inert gas mixtures

NASA Astrophysics Data System (ADS)

Chen, Yani; Zhao, Hongbin; Sheng, Leimei; Yu, Liming; An, Kang; Xu, Jiaqiang; Ando, Yoshinori; Zhao, Xinluo

2012-06-01

Large-scale production of graphene sheets has been achieved by direct current arc discharge evaporation of pure graphite electrodes in various H2-inert gas mixtures. The as-prepared few-layer graphene sheets have high purity, high crystallinity and high oxidation resistance temperature. Their electrochemical characteristics have been evaluated in coin-type cells versus metallic lithium. The first cell discharge capacity reached 1332 mA h g-1 at a current density of 50 mA g-1. After 350 cycles, the discharge capacity still remained at 323 mA h g-1. Graphene sheets produced by this method should be a promising candidate for the electrode material of lithium-ion batteries.

Toward assessing the diagnostic influence of dose reduction in pediatric CT: a study based on simulated lung nodules

NASA Astrophysics Data System (ADS)

Li, Xiang; Samei, Ehsan; DeLong, David M.; Jones, Robert P.; Colsher, James G.; Frush, Donald P.

2008-03-01

The purpose of this study is to evaluate the effect of reduced tube current, as a surrogate for radiation dose, on lung nodule detection in pediatric chest multi-detector CT (MDCT). Normal chest MDCT images of 13 patients aged 1 to 7 years old were used as templates for this study. The original tube currents were between 70 mA and 180 mA. Using proprietary noise addition software, noise was added to the images to create 13 cases at the lowest common mA (i.e. 70 mA), 13 cases at 35 mA (50% reduction), and 13 cases at 17.5 mA (75% reduction). Three copies of each case were made for a total of 117 series for simulated nodule insertion. A technique for three-dimensional simulation of small lung nodules was developed, validated through an observer study, and used to add nodules to the series. Care was taken to ensure that each of three lung zones (upper, middle, lower) contained 0 or 1 nodule. The series were randomized and the presence of a nodule in each lung zone was rated independently and blindly by three pediatric radiologists on a continuous scale between 0 (definitely absent) and 100 (definitely present). Receiver operating characteristic analysis of the data showed no general significant difference in diagnostic accuracy between the reduced mA values and 70 mA, suggesting a potential for dose reduction with preserved diagnostic quality. To our knowledge, this study is the first controlled, systematic, and task-specific assessment of the influence of dose reduction in pediatric chest CT.

Characteristics of cold atmospheric plasma source based on low-current pulsed discharge with coaxial electrodes

NASA Astrophysics Data System (ADS)

Bureyev, O. A.; Surkov, Yu S.; Spirina, A. V.

2017-05-01

This work investigates the characteristics of the gas discharge system used to create an atmospheric pressure plasma flow. The plasma jet design with a cylindrical graphite cathode and an anode rod located on the axis of the system allows to realize regularly reproducible spark breakdowns mode with a frequency ∼ 5 kHz and a duration ∼ 40 μs. The device generates a cold atmospheric plasma flame with 1 cm in diameter in the flow of various plasma forming gases including nitrogen and air at about 100 mA average discharge current. In the described construction the cathode spots of individual spark channels randomly move along the inner surface of the graphite electrode creating the secondary plasma stream time-average distributed throughout the whole exit aperture area after the decay of numerous filamentary discharge channels. The results of the spectral diagnostics of plasma in the discharge gap and in the stream coming out of the source are presented. Despite the low temperature of atoms and molecules in plasma stream the cathode spots operation with temperature of ∼ 4000 °C at a graphite electrode inside a discharge system enables to saturate the plasma by CN-radicals and atomic carbon in the case of using nitrogen as the working gas.

Decreased cerebral blood flow of the right anterior cingulate cortex in long-term and short-term abstinent methamphetamine users.

PubMed

Hwang, Jaeuk; Lyoo, In Kyoon; Kim, Seog Ju; Sung, Young Hoon; Bae, Soojeong; Cho, Sung-Nam; Lee, Ho Young; Lee, Dong Soo; Renshaw, Perry F

2006-04-28

The aim of the current study was to explore changes of relative regional cerebral blood flow (rCBF) in short-term and long-term abstinent methamphetamine (MA) users. Relative rCBF in 40 abstinent MA users and 23 healthy comparison subjects was compared by the technetium-99m-hexamethyl-propylene amine oxime ((99m)Tc-HMPAO) single photon emission computed tomography (SPECT). Relative rCBF in areas that were found to differ significantly was also compared in groups of MA users with short-term (<6 months) and long-term (>or=6 months) abstinence. MA users showed decreased relative rCBF in the right anterior cingulate cortex (Brodmann area 32) relative to healthy comparison subjects. Long-term abstinent MA users had significantly greater rCBF than short-term abstinent MA users. We report that abstinent MA users have decreased rCBF in the anterior cingulate cortex with smaller relative decreases in subjects with prolonged abstinence.

Network Management and FDIR for SpaceWire Networks (N-MaSS)

NASA Astrophysics Data System (ADS)

Montano, Giuseppe; Jameux, David; Cook, Barry; Peel, Rodger; McCormick, Ecaterina; Walker, Paul; Kollias, Vangelis; Pogkas, Nikos

2014-08-01

The SpaceWire network management layer, which manages network topology and routing, is not yet standardised. This paper presents the European Space Agency (ESA) N-MaSS study, which focuses on implementation and standardisation of Fault Detection, Isolation and Recovery (FDIR) functions within the SpaceWire network management layer. N-MaSS provides an autonomous FDIR solution. It is defined at the SpaceWire network layer in order to achieve efficient re-use for heterogeneous missions, allowing for the incorporation of legacy equipment. The N-MaSS FDIR functions identify SpaceWire link and node failures and provide recovery using redundant nodes.This paper provides an overview of the overall N- MaSS study. In particular, the following topics are discussed: (a) how user requirements have been captured from the industry, SpaceWire Working Group and ESA; (b) how the N-MaSS architecture was organically shaped on the basis of the requirements captured; (c) how the N-MaSS concept is currently being implemented in a demonstrator and verified.

Comparison of Exercise Performance in Recreationally Active and Masters Athlete Women.

PubMed

Stone, Matthew S; Glenn, Jordan M; Vincenzo, Jennifer L; Gray, Michelle

2018-02-01

Stone, MS, Glenn, JM, Vincenzo, JL, and Gray, M. Comparison of exercise performance in recreationally active and masters athlete women. J Strength Cond Res 32(2): 565-571, 2018-Master athletes (MA) are an understudied, ever-growing cohort. As such, it is important to examine how age affects muscular power and fatigability. Of particular interest is muscular power maintenance and fatigue mitigation of MA compared with young, healthy adults. The purpose of this investigation was to examine the differences in peak power, average power, total work (WRK), and fatigue index (FI) between recreationally active (RA) younger adults and female MA during anaerobic cycling exercise. Two groups, RA (n = 15; 20.6 ± 0.8 years) and MA (n = 17; 50.5 ± 8.6 years), participated in this study. Peak power, APWR, WRK, and FI were measured during a 30-second Wingate maximum anaerobic cycling protocol at a predetermined resistance of 7.5% body mass. Peak power (p = 0.92; RA: 654.1 ± 114.5 W; MA: 658.6 ± 147.6 W), APWR (p = 0.09; RA: 429.8 ± 73.3 W; MA: 384 ± 73.8 W), WRK (p = 0.09; RA: 12,894.3 ± 2,198.3 J; MA: 18,044.3 ± 27,184.9 J), and FI (p = 0.30; RA: 11.8 ± 4.1 W·s; MA: 14 ± 5.2 W·s) were not significantly different between groups. Master athletes produce power and WRK comparable to rates of fatigue among RA. This suggests that MA can maintain physical ability similar to RA in multiple parameters of high-intensity exercise while mitigating fatigue comparably. These data allow for advancements in exercise training and performance outcomes in MA populations. Further research within the MA population is warranted regarding other aspects of exercise and sport performance.

NASA S and MA at the Crossroads; The Role of NASA Quality Insight/Oversight for Commercial Crewed Launch Vehicles

NASA Technical Reports Server (NTRS)

Malone, Roy W., Jr.

2010-01-01

The presentation slides examine: The Journey, Current Safety and Mission Assurance (S and MA) Oversight/Insight, The Change, The Issue, Potential NASA relationship with Commercial Partners, and Commercial "X" FRR - Are you Go.

Time to relapse following treatment for methamphetamine use: a long-term perspective on patterns and predictors.

PubMed

Brecht, Mary-Lynn; Herbeck, Diane

2014-06-01

This paper describes methamphetamine (MA) use patterns, specifically the duration of continuing abstinence ("time to relapse") for periods averaging 5 years post-discharge from treatment for MA use, and the relationship with selected user and treatment characteristics. A sample of 350 treatment admissions from a large county substance use disorder (SUD) treatment system was randomly selected (within gender, race/ethnicity, treatment modality strata). Retrospective self-report data are from natural history interviews (NHI) conducted approximately 3 years after treatment and a follow-up of 2-3 years later. Relapse is defined as any use of MA with time as the number of months of continuous MA abstinence after treatment discharge until relapse. This outcome was constructed from a monthly MA use timeline using NHI data. A Cox model was used to examine time to relapse and predictors. Sixty-one percent of the sample relapsed to MA use within 1 year after treatment discharge and 14% during years 2-5. Significant protective factors predicting longer time to relapse included having experienced serious MA-related psychiatric/behavioral problems (hazard ratio [HR]=0.75, p=0.027), longer duration of the index treatment episode (HR=0.93, p=0.001), and participating in self-help or other treatment during the post-treatment abstinence period (HR=0.29, p<0.001); risk factors for shorter time to relapse included having a parent with alcohol and/or drug use problems (HR=1.35, p=0.020) and involvement in MA sales (HR=1.48, p=0.002). Results contribute a long-term perspective on patterns of MA use following treatment and support a need for early post-treatment and long-term continuing care and relapse-prevention services. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Composite of K-doped (NH4)2V3O8/graphene as an anode material for sodium-ion batteries.

PubMed

Liu, Xin; Li, Zhiwei; Fei, Hailong; Wei, Mingdeng

2015-11-21

A layer structured K-doped (NH4)2V3O8/graphene (K-NVG) was prepared via a hydrothermal route and then used as an anode material for sodium-ion batteries for the first time. The K-NVG nanosheets have a diameter in the range of 200-500 nm. The K-NVG electrode exhibited stable cycling and a good rate performance with a reversible capacity of 235.4 mA h g(-1), which is much higher than the 90.5 mA h g(-1) value of the (NH4)2V3O8/graphene electrode after 100 cycles at a current density of 100 mA g(-1). Simultaneously, the retention rate was maintained at 82% even after 250 cycles at the current density of 300 mA g(-1). Such good electrochemical properties may be attributed to the K-NVG's stable layered structure.

High-performance InGaN/GaN MQW LEDs with Al-doped ZnO transparent conductive layers grown by MOCVD using H2O as an oxidizer

NASA Astrophysics Data System (ADS)

Lin, Jia-Yong; Pei, Yan-Li; Zhuo, Yi; Chen, Zi-Min; Hu, Rui-Qin; Cai, Guang-Shuo; Wang, Gang

2016-11-01

In this study, the high performance of InGaN/GaN multiple quantum well light-emitting diodes (LEDs) with Al-doped ZnO (AZO) transparent conductive layers (TCLs) has been demonstrated. The AZO-TCLs were fabricated on the n+-InGaN contact layer by metal organic chemical vapor deposition (MOCVD) using H2O as an oxidizer at temperatures as low as 400 °C without any post-deposition annealing. It shows a high transparency (98%), low resistivity (510-4 Ω·cm), and an epitaxial-like excellent interface on p-GaN with an n+-InGaN contact layer. A forward voltage of 2.82 V @ 20 mA was obtained. Most importantly, the power efficiencies can be markedly improved by 53.8%@20 mA current injection and 39.6%@350 mA current injection compared with conventional LEDs with indium tin oxide TCL (LED-III), and by 28.8%@20 mA current injection and 4.92%@350 mA current injection compared with LEDs with AZO-TCL prepared by MOCVD using O2 as an oxidizer (LED-II), respectively. The results indicate that the AZO-TCL grown by MOCVD using H2O as an oxidizer is a promising TCL for a low-cost and high-efficiency GaN-based LED application. Project supported by the National Natural Science Foundation of China (Grant Nos. 61204091, 61404177, 51402366, and U1201254) and the Science and Technology Planning Project of Guangdong Province, China (Grant No. 2015B010132006).

GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction

NASA Astrophysics Data System (ADS)

Zhou, Shengjun; Zheng, Chenju; Lv, Jiajiang; Gao, Yilin; Wang, Ruiqing; Liu, Sheng

2017-07-01

We demonstrate GaN-based double-layer electrode flip-chip light-emitting diodes (DLE-FCLED) with highly reflective indium-tin oxide (ITO)/distributed bragg reflector (DBR) p-type contact and via hole-based n-type contacts. Transparent thin ITO in combination with TiO2/SiO2 DBR is used for reflective p-type ohmic contact, resulting in a significant reduction in absorption of light by opaque metal electrodes. The finely distributed via hole-based n-type contacts are formed on the n-GaN layer by etching via holes through p-GaN and multiple quantum well (MQW) active layer, leading to reduced lateral current spreading length, and hence alleviated current crowding effect. The forward voltage of the DLE-FCLED is 0.31 V lower than that of the top-emitting LED at 90 mA. The light output power of DLE-FCLED is 15.7% and 80.8% higher than that of top-emitting LED at 90 mA and 300 mA, respectively. Compared to top- emitting LED, the external quantum efficiency (EQE) of DLE-FCLED is enhanced by 15.4% and 132% at 90 mA and 300 mA, respectively. The maximum light output power of the DLE-FCLED obtained at 195.6 A/cm2 is 1.33 times larger than that of the top-emitting LED obtained at 93 A/cm2.

Age of the Scan Basin (Scotia Sea)

NASA Astrophysics Data System (ADS)

Schreider, Al. A.; Schreider, A. A.; Galindo-Zaldivar, J.; Maldonado, A.; Sazhneva, A. E.; Evsenko, E. I.

2017-03-01

Integrated geological and geophysical analysis of the anomalous magnetic field along with the previously unpublished profiles of Spanish expeditions onboard the R/V Hesperides and international databases of geomagnetic data processed in the context of the global tectonics concepts made it possible to identify paleomagnetic anomalies C11-C15 and compile the first map of the bottom geochronology of the Scan Basin. Unlike in earlier known publications, the paleoaxis of spreading does extend northeast, but approximately at an angle of 345°. According to calculations, spreading began 35.294‒35.706 Ma ago during chron C15r, and the spreading paleoaxis was abandoned 29.527‒29.970 Ma ago during chron C11n.2n. Thus, the destruction of the American-Antarctic bridge in the region joining the Bruce and Discovery banks with formation of oceanic crust in the Scan Basin started about 36 Ma ago. Regular spreading of the bottom has been continuing for about 6 Ma at a average rate close to 1.8 cm/year.

Patterns and average rates of late Neogene Recent uplift of the Betic Cordillera, SE Spain

NASA Astrophysics Data System (ADS)

Braga, Juan C.; Martín, José M.; Quesada, Cecilio

2003-02-01

The facies distribution in the sedimentary units infilling a series of Neogene basins has been used to reconstruct the relief generation and uplift across the Internal Zone of the Betic Cordillera in southern Spain. Uplift amounts and average rates can be estimated using the current elevation of the outcrops of well-dated deposits indicative of ancient sea-level positions. Coral reefs and coastal conglomerates record the initial development of emergent Betic relief during the Langhian. Continental and marginal marine deposits indicate the existence of a large island centred on the present Sierra Nevada-Sierra de los Filabres chain by the end of the Middle Miocene. The precursor of the Sierra Nevada-Sierra de los Filabres chain, originally part of this large island, remained emerged whilst the surrounding areas were re-invaded by the sea during the early Tortonian. At the end of the Tortonian the inland basins (Granada and Guadix basins) became continental, while the Sierras de la Contraviesa, Sierra de Gádor and Sierra Alhamilla emerged, separating the Alborán Basin from the Alpujarra, Tabernas and Sorbas basins, which became narrow passages of the Mediterranean Sea. In contrast, the Sierra Cabrera emerged during the late Messinian, suggesting a progressive uplift from west to east of the sierras south of the Sierra Nevada-Sierra de los Filabres chain. During the Pliocene, only the low areas closest to the present-day coast remained as marine basins and progressively emerged throughout this stage. The highest average uplift rate recorded is 280 m/Ma for the Sierra de Gádor, although the average uplift rates of upper-Neogene coastal marine rocks since depositon have maximum values of approximately 200 m/Ma. Most of the uplift of the Betic mountains took place before the early Pliocene. The recorded uplift of Neogene rocks was highest at the margins of western Sierra Nevada, where peaks higher than 3000 m occur. The average rates of uplift were lower to the east of this major relief. The main sierras and depressions in the present-day landscape correspond respectively to the emergent land, in which uplift was concentrated, and to the marine basins that existed before the final emergence of the region. The altitude of the sierras reflects the time at which they became emergent, the highest mountains being the first to rise above sea level.

Simulation study on transient electric shock characteristics of human body under high voltage ac transmission lines

NASA Astrophysics Data System (ADS)

Huang, Tao; Zou, Yanhui; Lv, Jianhong; Yang, Jinchun; Tao, Li; Zhou, Jianfei

2017-09-01

Human body under high-voltage AC transmission lines will produce a certain induced voltage due to the electrostatic induction. When the human body contacts with some grounded objects, the charges transfer from the body to the ground and produce contact current which may cause transient electric shock. Using CDEGS and ATP/EMTP, the paper proposes a method for quantitatively calculating the transient electric shock characteristics. It calculates the human body voltage, discharge current and discharge energy under certain 500kV compact-type transmission lines and predicts the corresponding human feelings. The results show that the average root value of discharge current is less than 10mA when the human body is under the 500kV compact-type transmission lines and the human body is overall safe if the transmission lines satisfy the relevant design specifications. It concludes that the electric field strength above the ground should be limited to 4kV/m through the residential area for the purpose of reducing the electromagnetic impact.

Enhanced Performance of GaN-Based Green Light-Emitting Diodes with Gallium-Doped ZnO Transparent Conducting Oxide

NASA Astrophysics Data System (ADS)

Oh, Min-Suk; Seo, Inseok

2014-04-01

Ga-doped ZnO (GZO) transparent conducting oxide was grown by oxygen plasma-enhanced pulsed laser deposition. GZO grown in the presence of oxygen radicals had resistivity of 1 × 10-3 Ω cm and average visible (500-700 nm) transmittance of 92.5%. A low specific contact resistance of 6.5 × 10-4 Ω cm2 of GZO on p-GaN was achieved by excimer laser annealing (ELA) treatment of p-GaN before GZO electrode deposition. The ELA-treated light emitting diode (LED) fabricated with the GZO electrode as a current-spreading layer resulted in light-output power enhanced by 56.2% at 100 mA compared with that fabricated with a conventional Ni/Au metal electrode. The high-light output and low degradation of light-output power were attributed to the decrease in contact resistance between the p-GaN layer and the GZO electrode and uniform current spreading over the p-GaN layer. In addition, low contact resistance results in a decrease of self-heat generation during current drive.

Metabolic engineering of the L-phenylalanine pathway in Escherichia coli for the production of S- or R-mandelic acid

PubMed Central

2011-01-01

Background Mandelic acid (MA), an important component in pharmaceutical syntheses, is currently produced exclusively via petrochemical processes. Growing concerns over the environment and fossil energy costs have inspired a quest to develop alternative routes to MA using renewable resources. Herein we report the first direct route to optically pure MA from glucose via genetic modification of the L-phenylalanine pathway in E. coli. Results The introduction of hydroxymandelate synthase (HmaS) from Amycolatopsis orientalis into E. coli led to a yield of 0.092 g/L S-MA. By combined deletion of competing pathways, further optimization of S-MA production was achieved, and the yield reached 0.74 g/L within 24 h. To produce R-MA, hydroxymandelate oxidase (Hmo) from Streptomyces coelicolor and D-mandelate dehydrogenase (DMD) from Rhodotorula graminis were co-expressed in an S-MA-producing strain, and the resulting strain was capable of producing 0.68 g/L R-MA. Finally, phenylpyruvate feeding experiments suggest that HmaS is a potential bottleneck to further improvement in yields. Conclusions We have constructed E. coli strains that successfully accomplished the production of S- and R-MA directly from glucose. Our work provides the first example of the completely fermentative production of S- and R-MA from renewable feedstock. PMID:21910908

Enhanced lithium storage in Fe2O3-SnO2-C nanocomposite anode with a breathable structure

NASA Astrophysics Data System (ADS)

Rahman, Md Mokhlesur; Glushenkov, Alexey M.; Ramireddy, Thrinathreddy; Tao, Tao; Chen, Ying

2013-05-01

A novel nanocomposite architecture of a Fe2O3-SnO2-C anode, based on clusters of Fe2O3 and SnO2 nanoparticles dispersed along the conductive chains of Super P Li™ carbon black (Timcal Ltd.), is presented as a breathable structure in this paper for lithium-ion batteries. The synthesis of the nanocomposite is achieved by combining a molten salt precipitation process and a ball milling method for the first time. The crystalline structure, morphology, and electrochemical characterization of the synthesised product are investigated systematically. Electrochemical results demonstrate that the reversible capacity of the composite anode is 1110 mA h g-1 at a current rate of 158 mA g-1 with only 31% of initial irreversible capacity in the first cycle. A high reversible capacity of 502 mA h g-1 (higher than the theoretical capacity of graphite, ~372 mA h g-1) can be obtained at a high current rate of 3950 mA g-1. The electrochemical performance is compared favourably with those of Fe2O3-SnO2 and Fe2O3-SnO2-C composite anodes for lithium-ion batteries reported in the literature. This work reports a promising method for the design and preparation of nanocomposite electrodes for lithium-ion batteries.A novel nanocomposite architecture of a Fe2O3-SnO2-C anode, based on clusters of Fe2O3 and SnO2 nanoparticles dispersed along the conductive chains of Super P Li™ carbon black (Timcal Ltd.), is presented as a breathable structure in this paper for lithium-ion batteries. The synthesis of the nanocomposite is achieved by combining a molten salt precipitation process and a ball milling method for the first time. The crystalline structure, morphology, and electrochemical characterization of the synthesised product are investigated systematically. Electrochemical results demonstrate that the reversible capacity of the composite anode is 1110 mA h g-1 at a current rate of 158 mA g-1 with only 31% of initial irreversible capacity in the first cycle. A high reversible capacity of 502 mA h g-1 (higher than the theoretical capacity of graphite, ~372 mA h g-1) can be obtained at a high current rate of 3950 mA g-1. The electrochemical performance is compared favourably with those of Fe2O3-SnO2 and Fe2O3-SnO2-C composite anodes for lithium-ion batteries reported in the literature. This work reports a promising method for the design and preparation of nanocomposite electrodes for lithium-ion batteries. Electronic supplementary information (ESI) available: Electrochemical Impedance Spectroscopy (EIS). See DOI: 10.1039/c3nr00690e

Apollo 12 breccia 12013: Impact-induced partial Pb loss in zircon and its implications for lunar geochronology

NASA Astrophysics Data System (ADS)

Thiessen, F.; Nemchin, A. A.; Snape, J. F.; Bellucci, J. J.; Whitehouse, M. J.

2018-06-01

Apollo 12 breccia 12013 is composed of two portions, one grey in colour, the other black. The grey portion of the breccia consists mainly of felsite thought to have formed during a single crystallisation event, while the black part is characterized by presence of lithic fragments of noritic rocks and individual plagioclase crystals. In this study, U-Pb analyses of Ca-phosphate and zircon grains were conducted in both portions of the breccia. The zircon grains within the grey portion yielded a large range of ages (4154 ± 7 to 4308 ± 6 Ma, 2σ) and show decreasing U and Th concentrations within the younger grains. Moreover, some grains exhibit recrystallisation features and potentially formation of neoblasts. The latter process requires high temperatures above 1600-1700 °C leading to the decomposition of the primary zircon grain and subsequent formation of new zircon occurring as neoblasts. As a result of the high temperatures, the U-Pb system of the remaining original zircon grains was most likely open for Pb diffusion causing partial resetting and the observed range of 207Pb/206Pb ages. The event that led to the Pb loss in zircon could potentially be dated by the U-Pb system in Ca-phosphates, which have a weighted average 207Pb/206Pb age across both lithologies of 3924 ± 3 Ma (95% conf.). This age is identical within error to the combined average 207Pb/206Pb age of 3926 ± 2 Ma that was previously obtained from Ca-phosphates within Apollo 14 breccias, zircon grains in Apollo 12 impact melt breccias, and the lunar meteorite SaU 169. This age was interpreted to date the Imbrium impact. The zircon grains located within the black portion of the breccia yielded a similar range of ages (4123 ± 13 to 4328 ± 14 Ma, 2σ) to those in the grey portion. Given the brecciated nature of this part of the sample, the interpretation of these ages as representing igneous crystallisation or resetting by impact events remains ambiguous since there is no direct link to their source rocks via textural relationships or crystal chemistry. Similarly, the currently available zircon data set for all lunar samples may be distorted by partial Pb loss, resulting in meaningless and misleading age distribution patterns. Therefore, it is crucial to fully understand and recognize the processes and conditions that may lead to partial resetting of the U-Pb system in zircon in order to better constrain the magmatic and impact history of the Moon.

Reply to comment by Ma and Zhang on "Rescaling the complementary relationship for land surface evaporation"

NASA Astrophysics Data System (ADS)

Crago, Richard; Qualls, Russell; Szilagyi, Jozsef; Huntington, Justin

2017-07-01

Ma and Zhang (2017) note a concern they have with our rescaled Complementary Relationship (CR) for land surface evaporation when daily average wind speeds are very low (perhaps less than 1 m/s). We discuss conditions and specific formulations that lead to this concern, but ultimately argue that under these conditions, a key assumption behind the CR itself may not be satisfied at the daily time scale. Thus, careful consideration of the reliability of the CR is needed when wind speeds are very low.

Study on the influence of three-grid assembly thermal deformation on breakdown times and an ion extraction process

NASA Astrophysics Data System (ADS)

Mingming, SUN; Yanhui, JIA; Yongjie, HUANG; Juntai, YANG; Xiaodong, WEN; Meng, WANG

2018-04-01

In order to study the influence of three-grid assembly thermal deformation caused by heat accumulation on breakdown times and an ion extraction process, a hot gap test and a breakdown time test are carried out to obtain thermal deformation of the grids when the thruster is in 5 kW operation mode. Meanwhile, the fluid simulation method and particle-in-cell-Monte Carlo collision (PIC-MCC) method are adopted to simulate the ion extraction process according to the previous test results. The numerical calculation results are verified by the ion thruster performance test. The results show that after about 1.2 h operation, the hot gap between the screen grid and the accelerator grid reduce to 0.25–0.3 mm, while the hot gap between the accelerator grid and the decelerator grid increase from 1 mm to about 1.4 mm when the grids reach thermal equilibrium, and the hot gap is almost unchanged. In addition, the breakdown times experiment shows that 0.26 mm is the minimal safe hot gap for the grid assembly as the breakdown times improves significantly when the gap is smaller than this value. Fluid simulation results show that the plasma density of the screen grid is in the range 6 × 1017–6 × 1018 m13 and displays a parabolic characteristic, while the electron temperature gradually increases along the axial direction. The PIC-MCC results show that the current falling of an ion beam through a single aperture is significant. Meanwhile, the intercepted current of the accelerator grid and the decelerator grid both increase with the change in the hot gap. The ion beam current has optimal perveance status without thermal deformation, and the intercepted current of the accelerator grid and the decelerator grid are 3.65 mA and 6.26 mA, respectively. Furthermore, under the effect of thermal deformation, the ion beam current has over-perveance status, and the intercepted current of the accelerator grid and the decelerator grid are 10.46 mA and 18.24 mA, respectively. Performance test results indicate that the breakdown times increase obviously. The intercepted current of the accelerator grid and the decelerator grid increases to 13 mA and 16.5 mA, respectively, due to the change in the hot gap after 1.5 h operation. The numerical calculation results are well consistent with performance test results, and the error comes mainly from the test uncertainty of the hot gap.

Automated image analysis method for detecting and quantifying macrovesicular steatosis in hematoxylin and eosin-stained histology images of human livers.

PubMed

Nativ, Nir I; Chen, Alvin I; Yarmush, Gabriel; Henry, Scot D; Lefkowitch, Jay H; Klein, Kenneth M; Maguire, Timothy J; Schloss, Rene; Guarrera, James V; Berthiaume, Francois; Yarmush, Martin L

2014-02-01

Large-droplet macrovesicular steatosis (ld-MaS) in more than 30% of liver graft hepatocytes is a major risk factor for liver transplantation. An accurate assessment of the ld-MaS percentage is crucial for determining liver graft transplantability, which is currently based on pathologists' evaluations of hematoxylin and eosin (H&E)-stained liver histology specimens, with the predominant criteria being the relative size of the lipid droplets (LDs) and their propensity to displace a hepatocyte's nucleus to the cell periphery. Automated image analysis systems aimed at objectively and reproducibly quantifying ld-MaS do not accurately differentiate large LDs from small-droplet macrovesicular steatosis and do not take into account LD-mediated nuclear displacement; this leads to a poor correlation with pathologists' assessments. Here we present an improved image analysis method that incorporates nuclear displacement as a key image feature for segmenting and classifying ld-MaS from H&E-stained liver histology slides. 52,000 LDs in 54 digital images from 9 patients were analyzed, and the performance of the proposed method was compared against the performance of current image analysis methods and the ld-MaS percentage evaluations of 2 trained pathologists from different centers. We show that combining nuclear displacement and LD size information significantly improves the separation between large and small macrovesicular LDs (specificity = 93.7%, sensitivity = 99.3%) and the correlation with pathologists' ld-MaS percentage assessments (linear regression coefficient of determination = 0.97). This performance vastly exceeds that of other automated image analyzers, which typically underestimate or overestimate pathologists' ld-MaS scores. This work demonstrates the potential of automated ld-MaS analysis in monitoring the steatotic state of livers. The image analysis principles demonstrated here may help to standardize ld-MaS scores among centers and ultimately help in the process of determining liver graft transplantability. © 2013 American Association for the Study of Liver Diseases.

Binge use and sex and drug use behaviors among HIV(-), heterosexual methamphetamine users in San Diego.

PubMed

Cheng, W Susan; Garfein, Richard S; Semple, Shirley J; Strathdee, Steffanie A; Zians, James K; Patterson, Thomas L

2010-01-01

This study identified sociodemographic factors, drug using practices, sexual behaviors, and motivational factors associated with binge (a period of uninterrupted) methamphetamine (MA) use among heterosexual MA users. The FASTLANE study provided cross-sectional data collected by audio computer-assisted self-interview (ACASI) between June 2001 and August 2004 from 451 HIV-negative MA users in San Diego, California, USA who had engaged in unprotected sex and used MA in the previous two months. The study sample was 67.8% male, 49.4% Caucasian, 26.8% African-American, and 12.8% Hispanic with a mean age of 36.6 years; 183 (40.5%) reported binge use in the past 2 months. Compared with non-binge users, binge users of MA were more likely to report risky drug use and sex behaviors and differed in motivations to initiate and currently use MA. The final logistic regression model for binge use included more days of MA use in the last month, ever treated for MA use, injection drug use, higher Beck Depression Inventory score, "experimentation" as a motivation for initiating MA use, and engaging in sex marathons while high on MA. HIV prevention efforts should differentiate and address these differences in motivations for MA use and the associated HIV-risk sex and drug use behaviors as key targets for effective intervention.

Social networks and alcohol use among older adults: a comparison with middle-aged adults.

PubMed

Kim, Seungyoun; Spilman, Samantha L; Liao, Diana H; Sacco, Paul; Moore, Alison A

2018-04-01

This study compared the association between social networks and alcohol consumption among middle-aged (MA) and older adults (OA) to better understand the nature of the relationship between those two factors among OA and MA. We examined Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Current drinkers aged over 50 were subdivided into two age groups: MA (50-64, n = 5214) and OA (65 and older, n = 3070). Each age group was stratified into drinking levels (low-risk vs. at-risk) based on alcohol consumption. The size and diversity of social networks were measured. Logistic regression models were used to examine age differences in the association between the social networks (size and diversity) and the probability of at-risk drinking among two age groups. A significant association between the social networks diversity and lower odds of at-risk drinking was found among MA and OA. However, the relationship between the diversity of social networks and the likelihood of at-risk drinking was weaker for OA than for MA. The association between social networks size and at-risk drinking was not significant among MA and OA. The current study suggests that the association between social networks diversity and alcohol use among OA differs from the association among MA, and few social networks were associated with alcohol use among OA. In the future, research should consider an in-depth exploration of the nature of social networks and alcohol consumption by using longitudinal designs and advanced methods of exploring drinking networks.

Social networks and alcohol use among older adults: a comparison with middle-aged adults

PubMed Central

Kim, Seungyoun; Spilman, Samantha L.; Liao, Diana H.; Sacco, Paul; Moore, Alison A.

2017-01-01

Objectives This study compared the association between social networks and alcohol consumption among middle-aged (MA) and older adults (OA) to better understand the nature of the relationship between those two factors among OA and MA. Method We examined Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Current drinkers aged over 50 were subdivided into two age groups: MA (50–64, n = 5214) and OA (65 and older, n = 3070). Each age group was stratified into drinking levels (low-risk vs. at-risk) based on alcohol consumption. The size and diversity of social networks were measured. Logistic regression models were used to examine age differences in the association between the social networks (size and diversity) and the probability of at-risk drinking among two age groups. Results A significant association between the social networks diversity and lower odds of at-risk drinking was found among MA and OA. However, the relationship between the diversity of social networks and the likelihood of at-risk drinking was weaker for OA than for MA. The association between social networks size and at-risk drinking was not significant among MA and OA. Conclusion The current study suggests that the association between social networks diversity and alcohol use among OA differs from the association among MA, and few social networks were associated with alcohol use among OA. In the future, research should consider an in-depth exploration of the nature of social networks and alcohol consumption by using longitudinal designs and advanced methods of exploring drinking networks. PMID:28006983

High power single mode 980 nm AlGaInAs/AlGaAs quantum well lasers with a very low threshold current

NASA Astrophysics Data System (ADS)

Zhen, Dong; Cuiluan, Wang; Hongqi, Jing; Suping, Liu; Xiaoyu, Ma

2013-11-01

To achieve low threshold current as well as high single mode output power, a graded index separate confinement heterostructure (GRIN-SCH) AlGaInAs/AlGaAs quantum well laser with an optimized ridge waveguide was fabricated. The threshold current was reduced to 8 mA. An output power of 76 mW was achieved at 100 mA current at room temperature, with a slope efficiency of 0.83 W/A and a horizon divergent angle of 6.3°. The maximum single mode output power of the device reached as high as 450 mW.

Numerical Analysis of the Temperature Impact on Performance of GaN-Based 460-nm Light-Emitting Diode.

PubMed

Tawfik, Wael Z; Lee, June Key

2018-03-01

The influence of temperature on the characteristics of a GaN-based 460-nm light-emitting diode (LED) prepared on sapphire substrate was simulated using the SiLENSe and SpeCLED software programs. High temperatures impose negative effects on the performance of GaN-based LEDs. As the temperature increases, electrons acquire higher thermal energies, and therefore LEDs may suffer more from high-current loss mechanisms, which in turn causes a reduction in the radiative recombination rate in the active region. The internal quantum efficiency was reduced by about 24% at a current density of 35 A/cm2, and the electroluminescence spectral peak wavelength was redshifted. The LED operated at 260 K and exhibited its highest light output power of ~317.5 mW at a maximum injection current of 350 mA, compared to 212.2 mW for an LED operated at 400 K. However, increasing temperature does not cause a droop in efficiency under high injection conditions. The peak efficiency at 1 mA of injection current decreases more rapidly by ~15% with increasing temperature from 260 to 400 K than the efficiency at high injection current of 350 mA by ~11%.

NATIONAL GEODATABASE OF TIDAL STREAM POWER RESOURCE IN USA

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

Smith, Brennan T; Neary, Vincent S; Stewart, Kevin M

2012-01-01

A geodatabase of tidal constituents is developed to present the regional assessment of tidal stream power resource in the USA. Tidal currents are numerically modeled with the Regional Ocean Modeling System (ROMS) and calibrated with the available measurements of tidal current speeds and water level surfaces. The performance of the numerical model in predicting the tidal currents and water levels is assessed by an independent validation. The geodatabase is published on a public domain via a spatial database engine with interactive tools to select, query and download the data. Regions with the maximum average kinetic power density exceeding 500 W/m2more » (corresponding to a current speed of ~1 m/s), total surface area larger than 0.5 km2 and depth greater than 5 m are defined as hotspots and documented. The regional assessment indicates that the state of Alaska (AK) has the largest number of locations with considerably high kinetic power density, followed by, Maine (ME), Washington (WA), Oregon (OR), California (CA), New Hampshire (NH), Massachusetts (MA), New York (NY), New Jersey (NJ), North and South Carolina (NC, SC), Georgia (GA), and Florida (FL).« less

Climate and tectonic evolution of the Descanso-Yauri basin in the northernmost Altiplano: Archetype example of a 'lithospheric drip' basin

NASA Astrophysics Data System (ADS)

Kar, N.; Garzione, C. N.

2015-12-01

We present a new multiproxy Miocene-Pliocene paleoelevation record of the northernmost Altiplano plateau reconstructed from pollen, clumped isotope (TΔ47) and δ18Oc of sedimentary carbonates and leaf wax n-alkane δD signatures. The ~18Ma to ~9Ma deposits of our study area, Descanso-Yauri basin in southern Peru show 11 to 16ºC warmer than modern mean annual air temperature, low elevation vegetation pollen assemblage (dominated by Podocarpus), and an average precipitation δ18Omw (VSMOW) value of -8.3±2.0‰ (2σ). The ~5 to 4 Ma deposits in the Descanso-Yauri basin are characterized by herb and shrub vegetation and an average δ18O mw (VSMOW) value of -14.6±3.0‰ (2σ), indicative of an elevation and/or climate similar to modern conditions. Based on the multiproxy paleoclimate record, we interpret that there was a 2±1 km surface uplift between 9 and 5 Ma in the northernmost Altiplano plateau. Deformation history analysis through map scale structural investigation combined with provenance analysis from conglomerate clast composition and paleocurrents show that the thrusts bounding the NE side of the Descanso-Yauri basin were active until ˜9Ma. Deformation waned afterwards, and switched to an extensional deformation regime, coincident with decrease in subsidence rate from ˜0.2mm/year to ˜0.03mm/year. Depositional history reconstructed by facies analysis and stratigraphic correlation reveal that deposition in the basin began with transverse braided river systems that formed along the thrust front and gave way to a larger fluvial-lacustrine system until ˜4 Ma. The basin deposits show an overall fining upward trend from coarse clastic dominated, in the lower most parts of the basin fill to fluvial overbank and lacustrine mudstone and diatomite deposits in the middle-upper parts. The thickest deposits formed in the central part of the basin. Based on these depositional and deformational patterns, we infer that the Descanso-Yauri basin formed in response to a growing eclogite and mantle root in the lower lithosphere. Removal of this root, possibly combined with lower crustal flow, led to the rapid 9-5 Ma surface uplift of the northernmost part of the Central Andean Plateau.

11.72 sq cm SiC Wafer-scale Interconnected 64 kA PiN Diode

DTIC Science & Technology

2012-01-30

drop of 10.3 V. The dissipated energy was 382 J and the calculated action exceeded 1.7 MA2 -s. Preliminary development of high voltage interconnection...scale diode action (surge current integral), a key reliability parameter, exceeded 1.7 MA2 -s. Figure 6: The wafer-scale interconnected diode...scale diode was 382 J and the calculated action exceeded 1.7 MA2 -sec. High voltage operation of PiN diodes, thyristors, and other semiconductor

Recent investigations of the 0-5 Ma geomagnetic field recorded by lava flows

NASA Astrophysics Data System (ADS)

Johnson, C. L.; Constable, C. G.; Tauxe, L.; Barendregt, R.; Brown, L. L.; Coe, R. S.; Layer, P.; Mejia, V.; Opdyke, N. D.; Singer, B. S.; Staudigel, H.; Stone, D. B.

2008-04-01

We present a synthesis of 0-5 Ma paleomagnetic directional data collected from 17 different locations under the collaborative Time Averaged geomagnetic Field Initiative (TAFI). When combined with regional compilations from the northwest United States, the southwest United States, Japan, New Zealand, Hawaii, Mexico, South Pacific, and the Indian Ocean, a data set of over 2000 sites with high quality, stable polarity, and declination and inclination measurements is obtained. This is a more than sevenfold increase over similar quality data in the existing Paleosecular Variation of Recent Lavas (PSVRL) data set, and has greatly improved spatial sampling. The new data set spans 78°S to 53°N, and has sufficient temporal and spatial sampling to allow characterization of latitudinal variations in the time-averaged field (TAF) and paleosecular variation (PSV) for the Brunhes and Matuyama chrons, and for the 0-5 Ma interval combined. The Brunhes and Matuyama chrons exhibit different TAF geometries, notably smaller departures from a geocentric axial dipole field during the Brunhes, consistent with higher dipole strength observed from paleointensity data. Geographical variations in PSV are also different for the Brunhes and Matuyama. Given the high quality of our data set, polarity asymmetries in PSV and the TAF cannot be attributed to viscous overprints, but suggest different underlying field behavior, perhaps related to the influence of long-lived core-mantle boundary conditions on core flow. PSV, as measured by dispersion of virtual geomagnetic poles, shows less latitudinal variation than predicted by current statistical PSV models, or by previous data sets. In particular, the Brunhes data reported here are compatible with a wide range of models, from those that predict constant dispersion as a function of latitude to those that predict an increase in dispersion with latitude. Discriminating among such models could be helped by increased numbers of low-latitude data and new high northern latitude sites. Tests with other data sets, and with simulations, indicate that some of the latitudinal signature previously observed in VGP dispersion can be attributed to the inclusion of low-quality, insufficiently cleaned data with too few samples per site. Our Matuyama data show a stronger dependence of dispersion on latitude than the Brunhes data. The TAF is examined using the variation of inclination anomaly with latitude. Best fit two-parameter models have axial quadrupole contributions of 2-4% of the axial dipole term, and axial octupole contributions of 1-5%. Approximately 2% of the octupole signature is likely the result of bias incurred by averaging unit vectors.

Intensity limits of the PSI Injector II cyclotron

NASA Astrophysics Data System (ADS)

Kolano, A.; Adelmann, A.; Barlow, R.; Baumgarten, C.

2018-03-01

We investigate limits on the current of the PSI Injector II high intensity separate-sector isochronous cyclotron, in its present configuration and after a proposed upgrade. Accelerator Driven Subcritical Reactors, neutron and neutrino experiments, and medical isotope production all benefit from increases in current, even at the ∼ 10% level: the PSI cyclotrons provide relevant experience. As space charge dominates at low beam energy, the injector is critical. Understanding space charge effects and halo formation through detailed numerical modelling gives clues on how to maximise the extracted current. Simulation of a space-charge dominated low energy high intensity (9.5 mA DC) machine, with a complex collimator set up in the central region shaping the bunch, is not trivial. We use the OPAL code, a tool for charged-particle optics calculations in large accelerator structures and beam lines, including 3D space charge. We have a precise model of the present (production) Injector II, operating at 2.2 mA current. A simple model of the proposed future (upgraded) configuration of the cyclotron is also investigated. We estimate intensity limits based on the developed models, supported by fitted scaling laws and measurements. We have been able to perform more detailed analysis of the bunch parameters and halo development than any previous study. Optimisation techniques enable better matching of the simulation set-up with Injector II parameters and measurements. We show that in the production configuration the beam current scales to the power of three with the beam size. However, at higher intensities, 4th power scaling is a better fit, setting the limit of approximately 3 mA. Currents of over 5 mA, higher than have been achieved to date, can be produced if the collimation scheme is adjusted.

Switching Characteristics of a 4H-SiC Based Bipolar Junction Transistor to 200 C

NASA Technical Reports Server (NTRS)

Niedra, Janis M.

2006-01-01

Static curves and resistive load switching characteristics of a 600 V, 4 A rated, SiC-based NPN bipolar power transistor (BJT) were observed at selected temperatures from room to 200 C. All testing was done in a pulse mode at low duty cycle (approx.0.1 percent). Turn-on was driven by an adjustable base current pulse and turn-off was accelerated by a negative base voltage pulse of 7 V. These base drive signals were implemented by 850 V, gated power pulsers, having rise-times of roughly 10 ns, or less. Base charge sweep-out with a 7 V negative pulse did not produce the large reverse base current pulse seen in a comparably rated Si-based BJT. This may be due to a very low charge storage time. The decay of the collector current was more linear than its exponential-like rise. Switching observations were done at base drive currents (I(sub B)) up to 400 mA and collector currents (I(sub C)) up to 4 A, using a 100 Omega non-inductive load. At I(sub B) = 400 mA and I(sub C) = 4 A, turn-on times typically varied from 80 to 94 ns, over temperatures from 23 to 200 C. As expected, lowering the base drive greatly extended the turn-on time. Similarly, decreasing the load current to I(sub C) = 1 A with I(sub B) = 400 mA produced turn-on times as short as 34 ns. Over the 23 to 200 C range, with I(sub B) = 400 mA and I(sub C) = 4 A, turn-off times were in the range of 72 to 84 ns with the 7 V sweep-out.

Efficient Low-Voltage Operation of a CW Gyrotron Oscillator at 233 GHz.

PubMed

Hornstein, Melissa K; Bajaj, Vikram S; Griffin, Robert G; Temkin, Richard J

2007-02-01

The gyrotron oscillator is a source of high average power millimeter-wave through terahertz radiation. In this paper, we report low beam power and high-efficiency operation of a tunable gyrotron oscillator at 233 GHz. The low-voltage operating mode provides a path to further miniaturization of the gyrotron through reduction in the size of the electron gun, power supply, collector, and cooling system, which will benefit industrial and scientific applications requiring portability. Detailed studies of low-voltage operation in the TE(2) (,) (3) (,) (1) mode reveal that the mode can be excited with less than 7 W of beam power at 3.5 kV. During CW operation with 3.5-kV beam voltage and 50-mA beam current, the gyrotron generates 12 W of RF power at 233.2 GHz. The EGUN electron optics code describes the low-voltage operation of the electron gun. Using gun-operating parameters derived from EGUN simulations, we show that a linear theory adequately predicts the low experimental starting currents.

Efficient Low-Voltage Operation of a CW Gyrotron Oscillator at 233 GHz

PubMed Central

Hornstein, Melissa K.; Bajaj, Vikram S.; Griffin, Robert G.; Temkin, Richard J.

2007-01-01

The gyrotron oscillator is a source of high average power millimeter-wave through terahertz radiation. In this paper, we report low beam power and high-efficiency operation of a tunable gyrotron oscillator at 233 GHz. The low-voltage operating mode provides a path to further miniaturization of the gyrotron through reduction in the size of the electron gun, power supply, collector, and cooling system, which will benefit industrial and scientific applications requiring portability. Detailed studies of low-voltage operation in the TE2,3,1 mode reveal that the mode can be excited with less than 7 W of beam power at 3.5 kV. During CW operation with 3.5-kV beam voltage and 50-mA beam current, the gyrotron generates 12 W of RF power at 233.2 GHz. The EGUN electron optics code describes the low-voltage operation of the electron gun. Using gun-operating parameters derived from EGUN simulations, we show that a linear theory adequately predicts the low experimental starting currents. PMID:17687412

Diagnostic for a high-repetition rate electron photo-gun and first measurements

NASA Astrophysics Data System (ADS)

Filippetto, D.; Doolittle, L.; Huang, G.; Norum, E.; Portmann, G.; Qian, H.; Sannibale, F.

2015-05-01

The APEX electron source at LBNL combines the high-repetition-rate with the high beam brightness typical of photoguns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment, opening the doors of the high average power to brightness-hungry applications as X-Ray FELs, MHz ultrafast electron diffraction etc.. As first step, a complete characterization of the beam parameters is foreseen at the Gun beam energy of 750 keV. Diagnostics for low and high current measurements have been installed and tested, and measurements of cathode lifetime and thermal emittance in a RF environment with mA current performed. The recent installation of a double slit system, a deflecting cavity and a high precision spectrometer, allow the exploration of the full 6D phase space. Here we discuss the present layout of the machine and future upgrades, showing the latest results at low and high repetition rate, together with the tools and techniques used.

The influence of NH3 on NO2 conversion in a dc corona discharge in N2:O2:CO2:NO2:NH3 mixture

NASA Astrophysics Data System (ADS)

Dors, Mirosław; Mizeraczyk, Jerzy; Czech, Tadeusz; Konieczka, Jerzy

1996-10-01

The aim of this paper is to investigate the influence of NH3 additive (540-1470 ppm) on the conversion of NO2 and the creation of NO and N2O in a mixture of N2:O2:CO2: NO2:NH3 subjected to the so-called direct current (dc) corona discharge. The dc corona discharge was generated in a needle-to-plate reactor. Seven positively polarized needles were used as one electrode and a stainless steel plate as the other. The time-averaged discharge current was varied from 0 to 7 mA. It was found that the dc corona discharge decomposed NO2 and produced NO and N2O. The reduction of NO2 was higher without NH3 additive if the residence time of the operating gas was relatively short. However, in a longer corona discharge processing the NH3 additive may be useful for reduction of NO2.

Water reduction by a p-GaInP2 photoelectrode stabilized by an amorphous TiO2 coating and a molecular cobalt catalyst

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

Gu, Jing; Yan, Yong; Young, James L.

2015-12-21

Producing hydrogen through solar water splitting requires the coverage of large land areas. Abundant metal-based molecular catalysts offer scalability, but only if they match noble metal activities. We report on a highly active p-GaInP2 photocathode protected through a 35-nm TiO2 layer functionalized by a cobaloxime molecular catalyst (GaInP2-TiO2-cobaloxime). This photoelectrode mediates H2 production with a current density of ~9"0mA"0cm-2 at a potential of 0"0V versus RHE under 1-sun illumination at pH"013. The calculated turnover number for the catalyst during a 20-h period is 139,000, with an average turnover frequency of 1.9"0s-1. Bare GaInP2 shows a rapid current decay, whereas themore » GaInP2-TiO2-cobaloxime electrode shows« less

ARMA Cholesky Factor Models for the Covariance Matrix of Linear Models.

PubMed

Lee, Keunbaik; Baek, Changryong; Daniels, Michael J

2017-11-01

In longitudinal studies, serial dependence of repeated outcomes must be taken into account to make correct inferences on covariate effects. As such, care must be taken in modeling the covariance matrix. However, estimation of the covariance matrix is challenging because there are many parameters in the matrix and the estimated covariance matrix should be positive definite. To overcomes these limitations, two Cholesky decomposition approaches have been proposed: modified Cholesky decomposition for autoregressive (AR) structure and moving average Cholesky decomposition for moving average (MA) structure, respectively. However, the correlations of repeated outcomes are often not captured parsimoniously using either approach separately. In this paper, we propose a class of flexible, nonstationary, heteroscedastic models that exploits the structure allowed by combining the AR and MA modeling of the covariance matrix that we denote as ARMACD. We analyze a recent lung cancer study to illustrate the power of our proposed methods.

New progress of high current gasdynamic ion source (invited).

PubMed

Skalyga, V; Izotov, I; Golubev, S; Sidorov, A; Razin, S; Vodopyanov, A; Tarvainen, O; Koivisto, H; Kalvas, T

2016-02-01

The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)-the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller's ECRIS confinement, i.e., the quasi-gasdynamic one similar to that in fusion mirror traps. Experimental studies of gasdynamic ECRIS were performed at Simple Mirror Ion Source (SMIS) 37 facility. The plasma was created by 37.5 and 75 GHz gyrotron radiation with power up to 100 kW. High frequency microwaves allowed to create and sustain plasma with significant density (up to 8 × 10(13) cm(-3)) and to maintain the main advantages of conventional ECRIS such as high ionization degree and low ion energy. Reaching such high plasma density relies on the fact that the critical density grows with the microwave frequency squared. High microwave power provided the average electron energy on a level of 50-300 eV enough for efficient ionization even at neutral gas pressure range of 10(-4)-10(-3) mbar. Gasdynamic ECRIS has demonstrated a good performance producing high current (100-300 mA) multi-charged ion beams with moderate average charge (Z = 4-5 for argon). Gasdynamic ECRIS has appeared to be especially effective in low emittance hydrogen and deuterium beams formation. Proton beams with current up to 500 emA and RMS emittance below 0.07 π ⋅ mm ⋅ mrad have been demonstrated in recent experiments.

Laser diodes using InAlGaAs multiple quantum wells intermixed to varying extent

NASA Astrophysics Data System (ADS)

Alahmadi, Yousef; LiKam Wa, Patrick

2018-02-01

Bandgap-modified InAlGaAs/InP multi-quantum well lasers have been demonstrated using an impurity-free disordering technique. Varying degrees of disordering are achieved by rapidly annealing silicon nitride-capped samples at temperatures ranging from 730°C to 830°C for 20 s. The lasing wavelength shift resulting from the intermixing, ranges between 28.2 nm and 147.2 nm. As the annealing temperature is increased, the lasing threshold currents of the fabricated waveguide lasers increase from 25mA to 45mA, while the slope efficiency decrease from 0.101 W/A to 0.068 W/A, compared to a threshold current of 27.8 mA and a slope efficiency of 0.121 W/A for an as-grown laser diode.

Asymmetry in growth and decay of the geomagnetic dipole revealed in seafloor magnetization

NASA Astrophysics Data System (ADS)

Avery, Margaret S.; Gee, Jeffrey S.; Constable, Catherine G.

2017-06-01

Geomagnetic intensity fluctuations provide important constraints on time-scales associated with dynamical processes in the outer core. PADM2M is a reconstructed time series of the 0-2 Ma axial dipole moment (ADM). After smoothing to reject high frequency variations PADM2M's average growth rate is larger than its decay rate. The observed asymmetry in rates of change is compatible with longer term diffusive decay of the ADM balanced by advective growth on shorter time scales, and provides a potentially useful diagnostic for evaluating numerical geodynamo simulations. We re-analyze the PADM2M record using improved low-pass filtering to identify asymmetry and quantify its uncertainty via bootstrap methods before applying the new methodology to other kinds of records. Asymmetry in distribution of axial dipole moment derivatives is quantified using the geomagnetic skewness coefficient, sg. A positive value indicates the distribution has a longer positive tail and the average growth rate is greater than the average decay rate. The original asymmetry noted by Ziegler and Constable (2011) is significant and does not depend on the specifics of the analysis. A long-term record of geomagnetic intensity should also be preserved in the thermoremanent magnetization of oceanic crust recovered by inversion of stacked profiles of marine magnetic anomalies. These provide an independent means of verifying the asymmetry seen in PADM2M. We examine three near-bottom surveys: a 0 to 780 ka record from the East Pacific Rise at 19°S, a 0 to 5.2 Ma record from the Pacific Antarctic Ridge at 51°S, and a chron C4Ar-C5r (9.3-11.2 Ma) record from the NE Pacific. All three records show an asymmetry similar in sense to PADM2M with geomagnetic skewness coefficients, sg > 0. Results from PADM2M and C4Ar-C5r are most robust, reflecting the higher quality of these geomagnetic records. Our results confirm that marine magnetic anomalies can carry a record of the asymmetric geomagnetic field behavior first found for 0-2 Ma in PADM2M, and show that it was also present during the earlier time interval from 9.3-11.2 Ma.

Dependence of average inter-particle distance upon the temperature of neutrals in dusty plasma crystals

NASA Astrophysics Data System (ADS)

Nikolaev, V. S.; Timofeev, A. V.

2018-01-01

It is often suggested that inter-particle distance in stable dusty plasma structures decreases with cooling as a square root of neutral gas temperature. Deviations from this dependence (up to the increase at cryogenic temperatures) found in the experimental results for the pressures range 0.1-8.0 mbar and for the currents range 0.1-1.0 mA are given. Inter-particle distance dependences on the charge of particles, parameter of the trap and the screening length in surrounding plasma are obtained for different conditions from molecular dynamics simulations. They are well approximated by power functions in the mentioned range of parameters. It is found that under certain assumptions thermophoretical force is responsible for inter-particle distance increase at cryogenic temperatures.

Monolithic integration of a vertical cavity surface emitting laser and a metal semiconductor field effect transistor

NASA Astrophysics Data System (ADS)

Yang, Y. J.; Dziura, T. G.; Bardin, T.; Wang, S. C.; Fernandez, R.; Liao, Andrew S. H.

1993-02-01

Monolithic integration of a vertical cavity surface emitting laser (VCSEL) and a metal semiconductor field effect transistor (MESFET) is reported for the first time. The epitaxial layers for both GaAs VCSELs and MESFETs are grown on an n-type GaAs substrate by molecular-beam epitaxy at the same time. The VCSELs with a 10-micron diam active region exhibit an average threshold current (Ith) of 6 mA and a continuous wave (CW) maximum power of 1.1 mW. The MESFETs with a 3-micron gate length have a transconductance of 50 mS/mm. The laser output is modulated by the gate voltage of the MESFETs and exhibits an optical/electrical conversion factor of 0.5 mW/V.

Calibration of the Permo-Triassic Magnetostratigraphic Time Scale: Constraints from the Dewey Lake Formation, West Texas

NASA Astrophysics Data System (ADS)

Chang, S.; Knight, K. B.; Renne, P. R.

2005-12-01

Magnetostratigraphy is potentially a powerful tool for deciphering the high resolution chronostratigraphy of events across the Permo-Triassic boundary, but few well-dated polarity reversals exist to serve as calibration. Red beds of the Dewey Lake Formation (DLF) of West Texas span three reversed polarity intervals (Steiner, 2001) in a section of the DLF at Caprock Canyons State Park, where two tuffs occur. Sanidine separated from these tuffs was analyzed by 40Ar/39Ar methods. Single crystal laser fusion 40Ar/39Ar analyses of 40 grains from the upper tuff yield a weighted mean age of 249.9 ± 2.4 Ma (2σ errors here and throughout). The clustering of single crystal data provides some assurance against xenocrystic contamination. Two age spectra from multigrain sanidine separates from the lower tuff yielded integrated ages of 248.9 ± 2.8 Ma and 249.7 ± 2.8 Ma and consistent plateau ages of 249.2 ± 2.4 Ma and 249.6 ± 2.4 Ma. Two age spectra from multigrain upper tuff sanidines lack strict plateaus but with overall flat age spectra, with integrated ages of 249.7 ± 2.8 Ma and 250.3 ± 2.8 Ma and plateau-like segments (>70% of 39Ar released) with ages of 249.9 ± 2.6 Ma and 249.9 ± 2.6 Ma, respectively. These results, compared with 40Ar/39Ar data (using the same FCs = 28.02 Ma standard calibration) from the GSSP section at Meishan, China, suggest that the Permo-Triassic boundary (249.8 Ma; recalculated from Renne et al., 1995) definitely occurs within the lower Dewey Lake Formation. The two tuffs, which bracket a normal to reverse geomagnetic polarity transition polarity (Steiner, 2001), have indistinguishable ages. The age of this Permo-Triassic polarity transition is thus best represented by the weighed average of their ages, ca. 249.7 Ma (based on accepted calibrations of the 40Ar/39Ar system). Further such constraints will facilitate high-resolution comparison of terrestrial and marine records across this critical time interval.

Integrated modelling of steady-state scenarios and heating and current drive mixes for ITER

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

Murakami, Masanori; Park, Jin Myung; Giruzzi, G.

2011-01-01

Recent progress on ITER steady-state (SS) scenario modelling by the ITPA-IOS group is reviewed. Code-to-code benchmarks as the IOS group's common activities for the two SS scenarios (weak shear scenario and internal transport barrier scenario) are discussed in terms of transport, kinetic profiles, and heating and current drive (CD) sources using various transport codes. Weak magnetic shear scenarios integrate the plasma core and edge by combining a theory-based transport model (GLF23) with scaled experimental boundary profiles. The edge profiles (at normalized radius rho = 0.8-1.0) are adopted from an edge-localized mode-averaged analysis of a DIII-D ITER demonstration discharge. A fullymore » noninductive SS scenario is achieved with fusion gain Q = 4.3, noninductive fraction f(NI) = 100%, bootstrap current fraction f(BS) = 63% and normalized beta beta(N) = 2.7 at plasma current I(p) = 8MA and toroidal field B(T) = 5.3 T using ITER day-1 heating and CD capability. Substantial uncertainties come from outside the radius of setting the boundary conditions (rho = 0.8). The present simulation assumed that beta(N)(rho) at the top of the pedestal (rho = 0.91) is about 25% above the peeling-ballooning threshold. ITER will have a challenge to achieve the boundary, considering different operating conditions (T(e)/T(i) approximate to 1 and density peaking). Overall, the experimentally scaled edge is an optimistic side of the prediction. A number of SS scenarios with different heating and CD mixes in a wide range of conditions were explored by exploiting the weak-shear steady-state solution procedure with the GLF23 transport model and the scaled experimental edge. The results are also presented in the operation space for DT neutron power versus stationary burn pulse duration with assumed poloidal flux availability at the beginning of stationary burn, indicating that the long pulse operation goal (3000s) at I(p) = 9 MA is possible. Source calculations in these simulations have been revised for electron cyclotron current drive including parallel momentum conservation effects and for neutral beam current drive with finite orbit and magnetic pitch effects.« less

Utilization Trends in Diagnostic Imaging for a Commercially Insured Population: A Study of Massachusetts Residents 2009 to 2013.

PubMed

Flaherty, Stephen; Mortele, Koenraad J; Young, Gary J

2018-06-01

To report utilization trends in diagnostic imaging among commercially insured Massachusetts residents from 2009 to 2013. Current Procedural Terminology codes were used to identify diagnostic imaging claims in the Massachusetts All-Payer Claims Database for the years 2009 to 2013. We reported utilization and spending annually by imaging modality using total claims, claims per 1,000 individuals, total expenditures, and average per claim payments. The number of diagnostic imaging claims per insured MA resident increased only 0.6% from 2009 to 2013, whereas nonradiology claims increased by 6% annually. Overall diagnostic imaging expenditures, adjusted for inflation, were 27% lower in 2009 than 2013, compared with an 18% increase in nonimaging expenditures. Average payments per claim were lower in 2013 than 2009 for all modalities except nuclear medicine. Imaging procedure claims per 1,000 MA residents increased from 2009 to 2013 by 13% in MRI, from 147 to 166; by 17% in ultrasound, from 453 to 530; and by 12% in radiography (x-ray), from 985 to 1,100. However, CT claims per 1,000 fell by 37%, from 341 to 213, and nuclear medicine declined 57%, from 89 claims per 1,000 to 38. Diagnostic imaging utilization exhibited negligible growth over the study period. Diagnostic imaging expenditures declined, largely the result of falling payments per claim in most imaging modalities, in contrast with increased utilization and spending on nonimaging services. Utilization of MRI, ultrasound, and x-ray increased from 2009 to 2013, whereas CT and nuclear medicine use decreased sharply, although CT was heavily impacted by billing code changes. Copyright © 2018 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Application of constant current, low voltage electrical stimulation systems to pig carcasses and its effects on pork quality.

PubMed

Channon, H A; Walker, P J; Kerr, M G; Baud, S R

2003-12-01

This study examined the effectiveness of a constant current, low voltage electrical stimulation system on improving pork quality when applied to pigs at 2 min post-exsanguination. A total of 48 female Duroc×Large White/Landrace pigs of 85-90 kg liveweight were randomly allocated immediately prior to slaughter to one of four constant current electrical stimulation treatments: control (no electrical stimulation), 50, 200 and 400 mA. Stimulation was applied to pig carcasses at 2 min post-exsanguination for 30 s. No differences (P>0.05) in WB shear force values, muscle lightness or PSE incidence of pork M. longissimus lumborum (LL) was found due to electrical stimulation treatment. Muscle pH of the LL muscle was lower (P<0.001) in carcasses in the 200 and 400 mA treatments compared to those from carcasses in both the 50 mA and control treatment groups, when measured at the various time points from 40 min to 8 h post-slaughter. Although carcasses stimulated with 200 and 400 mA had higher percentage drip loss (P<0.05) and purge (P<0.001), this was not found to impact WB shear force values, muscle lightness or PSE incidence.

3D Interconnected V6O13 Nanosheets Grown on Carbonized Textile via a Seed-Assisted Hydrothermal Process as High-Performance Flexible Cathodes for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Xu, Shixing; Cen, Dingcheng; Gao, Peibo; Tang, Huang; Bao, Zhihao

2018-03-01

Three-dimensional (3D) free-standing nanostructured materials have been proven to be one of the most promising electrodes for energy storage due to their enhanced electrochemical performance. And they are also widely studied for the wearable energy storage systems. In this work, interconnected V6O13 nanosheets were grown on the flexible carbonized textile (c-textile) via a seed-assisted hydrothermal method to form a 3D free-standing electrode for lithium-ion batteries (LIBs). The electrode exhibited a specific capacity of 170 mA h g-1 at a specific current of 300 mA g-1. With carbon nanotube (CNT) coating, its specific capacities further increased 12-40% at the various current rates. It could retain a reversible capacity of 130 mA h g-1, 74% of the initial capacity after 300 cycles at the specific current of 300 mA g-1. It outperformed most of the mixed-valence vanadium oxides. The improved electrochemical performance was ascribed to the synergistic effect of the 3D nanostructure of V6O13 for feasible Li+ diffusion and transport and highly conductive hierarchical conductive network formed by CNT and carbon fiber in c-textile.

Porous carbon derived from disposable shaddock peel as an excellent catalyst toward VO2+/VO2+ couple for vanadium redox battery

NASA Astrophysics Data System (ADS)

Liu, J.; Wang, Z. A.; Wu, X. W.; Yuan, X. H.; Hu, J. P.; Zhou, Q. M.; Liu, Z. H.; Wu, Y. P.

2015-12-01

Functional porous carbon (PC) derived from bio-friendly shaddock peel has been firstly explored as catalyst for vanadium redox flow battery (VRB). The prepared PC is micro-mesoporous with high BET surface area of 882.7 m2 g-1, has some surface oxygen-containing functional groups, and is doped with N and P heteroatoms. These three factors greatly favor the electrochemical reactions of VO2+/VO2+ on the PC modified glass carbon (PC-GC). Compared with the naked GC and graphite modified GC, the PC-GC presents a lower peak separation (66 mV), higher anodic current density (17.1 mA cm-2) and cathodic current density (15.0 mA cm-2). The VRB using PC modified graphite felt (GF) as positive electrode demonstrates an enhanced voltage efficiency of 82.7% at the current density of 60 mA cm-2, and a better rate performance than that from the virginal GF.

Co3O4 nanowire@NiO nanosheet arrays for high performance asymmetric supercapacitors.

PubMed

Xing, Lei; Dong, Yidi; Hu, Fang; Wu, Xiang; Umar, Ahmad

2018-04-24

Herein, we report a simple and facile sequential hydrothermal process for the synthesis of Co3O4 nanowire@NiO nanosheet arrays (CNAs). The as-synthesized CNAs were characterized in detail using various analytical techniques, which confirmed the high crystallinity, purity, and high-density growth of these nanomaterials. From an application point of view, the as-synthesized CNAs were directly used as supercapacitor electrodes, revealing a specific capacitance of up to 2018 mF cm-2 at a current density of 2 mA cm-2. Furthermore, a flexible asymmetric supercapacitor was fabricated using the as-synthesized CNAs as the anode and activated carbon as the cathode, which revealed a specific capacitance of 134.6 mF cm-2 at a current density of 2 mA cm-2. In addition, the supercapacitor showed excellent capacity retention of 73.5% after 10 000 cycles at a current density of 10 mA cm-2.

Photometric and Colorimetric Assessment of LED Chip Scale Packages by Using a Step-Stress Accelerated Degradation Test (SSADT) Method.

PubMed

Qian, Cheng; Fan, Jiajie; Fang, Jiayi; Yu, Chaohua; Ren, Yi; Fan, Xuejun; Zhang, Guoqi

2017-10-16

By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED) products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT) in LEDs, the thermal, photometric, and colorimetric properties of two types of LED chip scale packages (CSPs), i.e., 4000 °K and 5000 °K samples each of which was driven by two different levels of currents (i.e., 120 mA and 350 mA, respectively), were investigated under an increasing temperature from 55 °C to 150 °C and a systemic study of driving current effect on the SSADT results were also reported in this paper. During SSADT, junction temperatures of the test samples have a positive relationship with their driving currents. However, the temperature-voltage curve, which represents the thermal resistance property of the test samples, does not show significant variance as long as the driving current is no more than the sample's rated current. But when the test sample is tested under an overdrive current, its temperature-voltage curve is observed as obviously shifted to the left when compared to that before SSADT. Similar overdrive current affected the degradation scenario is also found in the attenuation of Spectral Power Distributions (SPDs) of the test samples. As used in the reliability qualification, SSADT provides explicit scenes on color shift and correlated color temperature (CCT) depreciation of the test samples, but not on lumen maintenance depreciation. It is also proved that the varying rates of the color shift and CCT depreciation failures can be effectively accelerated with an increase of the driving current, for instance, from 120 mA to 350 mA. For these reasons, SSADT is considered as a suitable accelerated test method for qualifying these two failure modes of LED CSPs.

Photometric and Colorimetric Assessment of LED Chip Scale Packages by Using a Step-Stress Accelerated Degradation Test (SSADT) Method

PubMed Central

Yu, Chaohua; Fan, Xuejun; Zhang, Guoqi

2017-01-01

By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED) products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT) in LEDs, the thermal, photometric, and colorimetric properties of two types of LED chip scale packages (CSPs), i.e., 4000 °K and 5000 °K samples each of which was driven by two different levels of currents (i.e., 120 mA and 350 mA, respectively), were investigated under an increasing temperature from 55 °C to 150 °C and a systemic study of driving current effect on the SSADT results were also reported in this paper. During SSADT, junction temperatures of the test samples have a positive relationship with their driving currents. However, the temperature-voltage curve, which represents the thermal resistance property of the test samples, does not show significant variance as long as the driving current is no more than the sample’s rated current. But when the test sample is tested under an overdrive current, its temperature-voltage curve is observed as obviously shifted to the left when compared to that before SSADT. Similar overdrive current affected the degradation scenario is also found in the attenuation of Spectral Power Distributions (SPDs) of the test samples. As used in the reliability qualification, SSADT provides explicit scenes on color shift and correlated color temperature (CCT) depreciation of the test samples, but not on lumen maintenance depreciation. It is also proved that the varying rates of the color shift and CCT depreciation failures can be effectively accelerated with an increase of the driving current, for instance, from 120 mA to 350 mA. For these reasons, SSADT is considered as a suitable accelerated test method for qualifying these two failure modes of LED CSPs. PMID:29035300

Field-Aligned Currents in Saturn's Nightside Magnetosphere: Subcorotation and Planetary Period Oscillation Components During Northern Spring

NASA Astrophysics Data System (ADS)

Bradley, T. J.; Cowley, S. W. H.; Provan, G.; Hunt, G. J.; Bunce, E. J.; Wharton, S. J.; Alexeev, I. I.; Belenkaya, E. S.; Kalegaev, V. V.; Dougherty, M. K.

2018-05-01

We newly analyze Cassini magnetic field data from the 2012/2013 Saturn northern spring interval of highly inclined orbits and compare them with similar data from late southern summer in 2008, thus providing unique information on the seasonality of the currents that couple momentum between Saturn's ionosphere and magnetosphere. Inferred meridional ionospheric currents in both cases consist of a steady component related to plasma subcorotation, together with the rotating current systems of the northern and southern planetary period oscillations (PPOs). Subcorotation currents during the two intervals show opposite north-south polar region asymmetries, with strong equatorward currents flowing in the summer hemispheres but only weak currents flowing to within a few degrees of the open-closed boundary (OCB) in the winter hemispheres, inferred due to weak polar ionospheric conductivities. Currents peak at 1 MA rad-1 in both hemispheres just equatorward of the open-closed boundary, associated with total downward polar currents 6 MA, then fall across the narrow auroral upward current region to small values at subauroral latitudes. PPO-related currents have a similar form in both summer and winter with principal upward and downward field-aligned currents peaking at 1.25 MA rad-1 being essentially collocated with the auroral upward current and approximately equal in strength. Though northern and southern PPO currents were approximately equal during both intervals, the currents in both hemispheres were dual modulated by both systems during 2012/2013, with approximately half the main current closing in the opposite ionosphere and half cross field in the magnetosphere, while only the northern hemisphere currents were similarly dual modulated in 2008.

Enhancement in c-Si solar cells using 16 nm InN nanoparticles

NASA Astrophysics Data System (ADS)

Imtiaz Chowdhury, Farsad; Alnuaimi, Aaesha; Alkis, Sabri; Ortaç, Bülend; Aktürk, Selçuk; Alevli, Mustafa; Dietz, Nikolaus; Kemal Okyay, Ali; Nayfeh, Ammar

2016-05-01

In this work, 16 nm indium nitride (InN) nanoparticles (NPs) are used to increase the performance of thin-film c-Si HIT solar cells. InN NPs were spin-coated on top of an ITO layer of c-Si HIT solar cells. The c-Si HIT cell is a stack of 2 μm p type c-Si, 4-5 nm n type a-Si, 15 nm n+ type a-Si and 80 nm ITO grown on a p+ type Si substrate. On average, short circuit current density (Jsc) increases from 19.64 mA cm-2 to 21.54 mA cm-2 with a relative improvement of 9.67% and efficiency increases from 6.09% to 7.09% with a relative improvement of 16.42% due to the presence of InN NPs. Reflectance and internal/external quantum efficiency (IQE/EQE) of the devices were also measured. Peak EQE was found to increase from 74.1% to 81.3% and peak IQE increased from 93% to 98.6% for InN NPs coated c-Si HIT cells. Lower reflection of light due to light scattering is responsible for performance enhancement between 400-620 nm while downshifted photons are responsible for performance enhancement from 620 nm onwards.

Membrane-less hybrid flow battery based on low-cost elements

NASA Astrophysics Data System (ADS)

Leung, P. K.; Martin, T.; Shah, A. A.; Mohamed, M. R.; Anderson, M. A.; Palma, J.

2017-02-01

The capital cost of conventional redox flow batteries is relatively high (>USD 200/kWh) due to the use of expensive active materials and ion-exchange membranes. This paper presents a membrane-less hybrid organic-inorganic flow battery based on the low-cost elements zinc (92.7% with the use of carbon felt electrodes. In the presence of a fully oxidized active species close to its solubility limit, dissolution of the deposited anode is relatively slow (<2.37 g h-1 cm-2) with an equivalent corrosion current density of <1.9 mA cm-2. In a parallel plate flow configuration, the resulting battery was charge-discharge cycled at 30 mA cm-2 with average coulombic and energy efficiencies of c.a. 71.8 and c.a. 42.0% over 20 cycles, respectively.

Intense combined source of neutrons and photons for interrogation based on compact deuteron RF accelerator

DOE PAGES

Kurennoy, S. S.; Garnett, R. W.; Rybarcyk, L. J.

2015-06-18

Interrogation of special nuclear materials can benefit from mobile sources providing significant fluxes of neutrons (10 8/s at 2.5 MeV, 10 10/s at 14.1 MeV) and of photons (>10 12/s at 1-3 MeV). We propose a source that satisfies these requirements simultaneously plus also provides, via the reaction 11B(d,n) 12C(γ 15.1), a significant flux of 15-MeV photons, which are highly penetrating and optimal for inducing photo-fission in actinides. The source is based on a compact (< 5 m) deuteron RF accelerator that delivers an average current of a few mA of deuterons at 3-4 MeV to a boron target.more » The accelerator consists of a short RFQ followed by efficient inter-digital H-mode structures with permanent-magnet-quadrupole beam focusing [Kurennoy et al. (2012)], which suit perfectly for deuteron acceleration at low energies. Our estimates, based on recent measurements, indicate that the required fluxes of both neutrons and photons can be achieved at ~1 mA of 4-MeV deuterons. The goal of the proposed study is to confirm feasibility of the approach and develop requirements for future full system implementation.« less

A wireless narrowband imaging chip for capsule endoscope.

PubMed

Lan-Rong Dung; Yin-Yi Wu

2010-12-01

This paper presents a dual-mode capsule gastrointestinal endoscope device. An endoscope combined with a narrowband image (NBI), has been shown to be a superior diagnostic tool for early stage tissue neoplasms detection. Nevertheless, a wireless capsule endoscope with the narrowband imaging technology has not been presented in the market up to now. The narrowband image acquisition and power dissipation reduction are the main challenges of NBI capsule endoscope. In this paper, we present the first narrowband imaging capsule endoscope that can assist clinical doctors to effectively diagnose early gastrointestinal cancers, profited from our dedicated dual-mode complementary metal-oxide semiconductor (CMOS) sensor. The dedicated dual-mode CMOS sensor can offer white-light and narrowband images. Implementation results show that the proposed 512 × 512 CMOS sensor consumes only 2 mA at a 3-V power supply. The average current of the NBI capsule with an 8-Mb/s RF transmitter is nearly 7 ~ 8 mA that can continuously work for 6 ~ 8 h with two 1.5-V 80-mAh button batteries while the frame rate is 2 fps. Experimental results on backside mucosa of a human tongue and pig's small intestine showed that the wireless NBI capsule endoscope can significantly improve the image quality, compared with a commercial-of-the-shelf capsule endoscope for gastrointestinal tract diagnosis.

Neural net forecasting for geomagnetic activity

NASA Technical Reports Server (NTRS)

Hernandez, J. V.; Tajima, T.; Horton, W.

1993-01-01

We use neural nets to construct nonlinear models to forecast the AL index given solar wind and interplanetary magnetic field (IMF) data. We follow two approaches: (1) the state space reconstruction approach, which is a nonlinear generalization of autoregressive-moving average models (ARMA) and (2) the nonlinear filter approach, which reduces to a moving average model (MA) in the linear limit. The database used here is that of Bargatze et al. (1985).

Corrosion of oxide dispersion strengthened iron-chromium steels and tantalum in fluoride salt coolant: An in situ compatibility study for fusion and fusion-fission hybrid reactor concepts

NASA Astrophysics Data System (ADS)

El-Dasher, Bassem; Farmer, Joseph; Ferreira, James; de Caro, Magdalena Serrano; Rubenchik, Alexander; Kimura, Akihiko

2011-12-01

Primary candidate classes of materials for future nuclear power plants, whether they be fission, fusion or hybrids, include oxide dispersion strengthened (ODS) ferritic steels which rely on a dispersion of nano-oxide particles in the matrix for both mechanical strength and swelling resistance, or tantalum alloys which have an inherent neutron-induced swelling resistance and high temperature strength. For high temperature operation, eutectic molten lithium containing fluoride salts are attractive because of their breeding capability as well as their relatively high thermal capacity, which allow for a higher average operating temperature that increases power production. In this paper we test the compatibility of Flinak (LiF-NaF-KF) salts on ODS steels, comparing the performance of current generation ODS steels developed at Kyoto University with the commercial alloy MA956. Pure tantalum was also tested for comparative purposes. In situ data was obtained for temperatures ranging from 600 to 900 °C using a custom-built high temperature electrochemical impedance spectroscopy cell. Results for ODS steels show that steel/coolant interfacial resistance increases from 600 to 800 °C due to an aluminum enriched layer forming at the surface, however an increase in temperature to 900 °C causes this layer to break up and aggressive attack to occur. Performance of current generation ODS steels surpassed that of the MA956 ODS steel, with an in situ impedance behavior similar or better than that of pure tantalum.

Pulsed direct and constant direct currents in the pilocarpine iontophoresis sweat chloride test.

PubMed

Gomez, Carla Cristina Souza; Servidoni, Maria de Fatima; Marson, Fernando Augusto de Lima; Canavezi, Paulo Jose Coelho; Vinagre, Adriana Mendes; Costa, Eduardo Tavares; Ribeiro, Antonio Fernando; Ribeiro, Maria Angela Gonçalves de Oliveira; Toro, Adyleia Aparecida Dalbo Contrera; Pavan, Celia Regina; Rondon, Michelle Vivine Sá Dos Santos; Lorena, Sonia Leticia Silva; Vieria, Francisco Ubaldi; Ribeiro, Jose Dirceu

2014-12-13

The classic sweat test (CST) is the golden standard for cystic fibrosis (CF) diagnosis. Then, our aim was compare the production and volume of sweat, and side effects caused by pulsed direct current (PDC) and constant direct current (CDC). To determine the optimal stimulation time (ST) for the sweat collection. To verify the PDC as CF diagnosis option. Prospective study with cross-sectional experimental intervention. Experiment 1 (right arm): PDC and CDC. ST at 10 min and sweat collected at 30 min. Currents of 0.5; 0.75; 1.0 and 1.5 mA and frequencies of 0, 200, 1,000 and 5,000 Hz applied. Experiment 2 (left arm): current of 1.0 mA, ST at 5 and 10 min and sweat collected at 15 and 30 min with frequencies of 0; 200; 1,000 and 5,000 Hz applied Experiments 1 and 2 were performed with current density (CD) from 0.07 to 0.21 mA/cm2. Experiment 3: PDC was used in typical CF patients with two CFTR mutations screened and or with CF diagnosis by rectal biopsy and patients with atypical CF. 48 subjects (79.16% female) with average of 29.54 ± 8.87 years old were enrolled. There was no statistical difference between the interaction of frequency and current in the sweat weight (p = 0.7488). Individually, positive association was achieved between weight sweat and stimulation frequency (p = 0.0088); and current (p = 0.0025). The sweat production was higher for 10 min of stimulation (p = 0.0023). The sweat collection was better for 30 min (p = 0.0019). The skin impedance was not influenced by ST and sweat collection (p > 0.05). The current frequency was inversely associated with the skin impedance (p < 0.0001). The skin temperature measured before stimulation was higher than after (p < 0.0001). In Experiment 3 (29 subjects) the PDC showed better kappa index compared to CDC (0.9218 versus 0.5205, respectively). The performance of the CST with CDC and PDC with CD of 0.14 to 0.21 mA/cm2 showed efficacy in steps of stimulation and collection of sweat, without side effects. The optimal stimulation time and sweat collection were, respectively, 10 and 30 min.

Review: magnetically assisted resistance spot welding

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

Li, Y. B.; Li, D. L.; Lin, Z. Q.

2016-02-25

Currently, the use of advanced high strength steels (AHSSs) is the most cost effective means of reducing vehicle body weight and maintaining structural integrity at the same time. However, AHSSs present a big challenge to the traditional resistance spot welding (RSW) widely applied in automotive industries because the rapid heating and cooling procedures during RSW produce hardened weld microstructures, which lower the ductility and fatigue properties of welded joints and raise the probability of interfacial failure under external loads. Changing process parameters or post-weld heat treatment may reduce the weld brittleness, but those traditional quality control methods also increase energymore » consumption and prolong cycle time. In recent years, a magnetically assisted RSW (MA-RSW) method was proposed, in which an externally applied magnetic field would interact with the conduction current to produce a Lorentz force that would affect weld nugget formation. This paper is a review of an experimental MA-RSW platform, the mode of the external magnetic field and the mechanism that controls nugget shape, weld microstructures and joint performance. In conclusion, the advantages of the MA-RSW method in improving the weldability of AHSSs are given, a recent application of the MA-RSW process to light metals is described and the outlook for the MA-RSW process is presented.« less

SU-E-I-31: Differences Observed in Radiation Doses Across 2 Similar CT Scanners From Adult Brain-Neck CT Angiography

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

Fujii, K; UCLA School of Medicine, Los Angeles, CA; McMillan, K

2015-06-15

Purpose: The aim of this study is to evaluate the difference in radiation doses from adult Brain-Neck CT angiography (CTA) between two CT scanners. Methods: We collected CT dose index data (CTDIvol, DLP) from adult Brain-Neck CTA performed with two CT scanners (Sensation 64 (S64) and Definition AS (AS), Siemens Healthcare) performed at two of our facilities from Jan 1st to Dec 31th, 2014. X-ray dose management software (Radmetrics, Bayer Healthcare) was used to mine these data. All exams were performed with Tube Current Modulation (Care Dose 4D), tube voltage of 120 kVp, quality reference mAs of 300, beam collimationmore » of 64*0.6 mm. The rotation time was set to 0.5 sec for S64 and 1.0 sec for AS. We also scanned an anthropomorphic skull and chest phantom under routine Brain-Neck CTA protocol with the two scanners and extracted the tube current values from the raw projection data. Results: The mean CTDIvol and DLP in Brain-Neck CTA was 72 mGy and 2554 mGy*cm for AS, which was substantially larger than the mean values of 46 mGy and 1699 mGy*cm for S64. The maximum tube current was 583 mA for most cases on the S64 while the maximum was 666 mA for AS even though the rotation time set for AS was 1.0 sec. Measurements obtained with the anthropomorphic phantom showed that the tube current reached 583 mA at the shoulder region for S64 while it reached to 666 mA for AS. Conclusion: The results of this study showed that substantially different CT doses can Result from Brain-Neck CTA protocols even when similar scanners and similar settings are used. Though both scanners have a similar maximum mA rating, differences in mA were observed through the shoulders, resulting in substantially different CTDIvol values.« less

Seasonal sea ice cover during the warm Pliocene: Evidence from the Iceland Sea (ODP Site 907)

NASA Astrophysics Data System (ADS)

Clotten, Caroline; Stein, Ruediger; Fahl, Kirsten; De Schepper, Stijn

2018-01-01

Sea ice is a critical component in the Arctic and global climate system, yet little is known about its extent and variability during past warm intervals, such as the Pliocene (5.33-2.58 Ma). Here, we present the first multi-proxy (IP25, sterols, alkenones, palynology) sea ice reconstructions for the Late Pliocene Iceland Sea (ODP Site 907). Our interpretation of a seasonal sea ice cover with occasional ice-free intervals between 3.50-3.00 Ma is supported by reconstructed alkenone-based summer sea surface temperatures. As evidenced from brassicasterol and dinosterol, primary productivity was low between 3.50 and 3.00 Ma and the site experienced generally oligotrophic conditions. The East Greenland Current (and East Icelandic Current) may have transported sea ice into the Iceland Sea and/or brought cooler and fresher waters favoring local sea ice formation. Between 3.00 and 2.40 Ma, the Iceland Sea is mainly sea ice-free, but seasonal sea ice occurred between 2.81 and 2.74 Ma. Sea ice extending into the Iceland Sea at this time may have acted as a positive feedback for the build-up of the Greenland Ice Sheet (GIS), which underwent a major expansion ∼2.75 Ma. Thereafter, most likely a stable sea ice edge developed close to Greenland, possibly changing together with the expansion and retreat of the GIS and affecting the productivity in the Iceland Sea.

Electrospinning preparation of oxygen-deficient nano TiO2-x/carbon fibre membrane as a self-standing high performance anode for Li-ion batteries

NASA Astrophysics Data System (ADS)

Jing, Mao-xiang; Li, Jing-quan; Han, Chong; Yao, Shan-shan; Zhang, Ji; Zhai, Hong-ai; Chen, Li-li; Shen, Xiang-qian; Xiao, Ke-song

2017-07-01

Improving the specific capacity and electronic conductivity of TiO2 can boost its practical application as a promising anode material for lithium ion batteries. In this work, a three-dimensional networking oxygen-deficient nano TiO2-x/carbon fibre membrane was achieved by combining the electrospinning process with a hot-press sintering method and directly used as a self-standing anode. With the synergistic effects of three-dimensional conductive networks, surface oxygen deficiency, high specific surface area and high porosity, binder-free and self-standing structure, etc., the nano TiO2-x/carbon fibre membrane electrode displays a high electrochemical reaction kinetics and a high specific capacity. The reversible capacity could be jointly generated from porous carbon, full-lithiation of TiO2 and interfacial lithium storage. At a current density of 100 mA g-1, the reversible discharge capacity can reach 464 mA h g-1. Even at 500 mA g-1, the discharge capacity still remains at 312 mA h g-1. Compared with pure carbon fibre and TiO2 powder, the TiO2-x/C fibre membrane electrode also exhibits an excellent cycle performance with a discharge capacity of 209 mA h g-1 after 700 cycles at the current density of 300 mA g-1, and the coulombic efficiency always remains at approximately 100%.

Endowing CuTCNQ with a new role: a high-capacity cathode for K-ion batteries.

PubMed

Ma, Jing; Zhou, En; Fan, Cong; Wu, Bo; Li, Chao; Lu, Zheng-Hong; Li, Jingze

2018-05-29

Herein, copper-tetracyanoquinodimethane (CuTCNQ) with phase-I kinetics character has been proposed as an effective cathode for potassium-ion batteries. In a voltage range of 2-4.1 V (vs. K+/K), both cuprous cations (Cu+) and organic anions (TCNQ-) are electrochemically active, and they render a three-electron redox mechanism, thereby enabling CuTCNQ to yield a high specific discharge capacity of 244 mA h g-1. Even after 50 cycles, the discharge capacity of 170 mA h g-1 is retained at 50 mA g-1. In addition, when the current density is elevated to 1000 mA g-1, the discharge capacity is still maintained at 125 mA h g-1. These test data are among the best results reported for high-potential cathodes of potassium-ion batteries.

Evaluation of constant current alternating current iontophoresis for transdermal drug delivery.

PubMed

Yan, Guang; Li, S Kevin; Higuchi, William I

2005-12-10

Previous studies in our laboratory have demonstrated that alternating current (AC) iontophoresis can significantly decrease skin electric resistance and enhance the transport of charged permeants across skin. Flux variability of neutral permeants during AC iontophoresis was also found to be less than that of conventional direct current (DC) iontophoresis. The objectives of the present study were to evaluate flux enhancement of constant current AC transdermal iontophoresis and compare the AC flux with that of constant current DC iontophoresis. Iontophoresis studies of AC amplitude of 1, 2, and 5 mA were conducted in side-by-side diffusion cells with donor solution of 0.015, 0.15, and 1.0 M tetraethylammonium (TEA) chloride and receiver solution of phosphate buffered saline (PBS) using human epidermal membrane (HEM). Conventional constant current DC iontophoresis of 0.2 mA was also performed under similar conditions. TEA and mannitol were the model permeants. The following are the major findings in the present study. The flux of TEA increased proportionally with the AC current for all three TEA chloride concentrations and at the AC frequency used in the present study. When the permeant and its counter ion were the only ionic species in the donor chamber, the fluxes during DC iontophoresis were weakly dependent of its donor concentration. The fluxes of TEA during constant current AC iontophoresis were moderately related to the donor concentration with the highest TEA flux observed under the 1.0 M TEA chloride condition although the relationship between flux and donor concentration was not linear. A trend of decreasing electroosmotic transport with increasing donor TEA chloride concentration was observed with significant sample-to-sample variability during DC iontophoresis. Mannitol permeability was also observed to decrease with increasing TEA chloride concentration in the donor under the AC conditions, but data variability under AC was significantly smaller than that under DC. The results in the present study indicate that constant current AC iontophoresis under conditions tolerable to human (2 and 5 mA) can provide predictable fluxes that were lower than but of comparable magnitude as those of conventional constant current DC iontophoresis (0.2 mA).

MA transmutation performance in the optimized MYRRHA

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

Malambu, E.; Van den Eynde, G.; Fernandez, R.

MYRRHA (multi-purpose hybrid research reactor for high-tech applications) is a multipurpose research facility currently being developed at SCK-CEN. It will be able to work in both critical and subcritical modes and, cooled by lead-bismuth eutectic. In this paper the minor actinides (MA) transmutation capabilities of MYRRHA are investigated. (Pu + Am, U) MOX fuel and (Np + Am + Cm, Pu) Inert Matrix Fuel test samples have been loaded in the central channel of the MYRRHA critical core and have been irradiated during five cycles, each one consisting of 90 days of operation at 100 MWth and 30 days ofmore » shutdown. The reactivity worth of the test fuel assembly was about 1.1 dollar. A wide range of burn-up level has been achieved, extending from 42 to 110 MWd/kg HM, the samples with lower MA-to-Pu ratios reaching the highest burn-up. This study has highlighted the importance of the initial MA content, expressed in terms of MA/Pu ratio, on the transmutation rate of MA elements. For (Pu + Am, U) MOX fuel samples, a net build-up of MA is observed when the initial content of MA is very low (here, 1.77 wt% MA/Pu) while a net decrease in MA is observed in the sample with an initial content of 5 wt%. This suggests the existence of some 'equilibrium' initial MA content value beyond which a net transmutation is achievable.« less

Measurements of high energy photons in Z-pinch experiments on primary test stand

NASA Astrophysics Data System (ADS)

Si, Fenni; Zhang, Chuanfei; Xu, Rongkun; Yuan, Xi; Huang, Zhanchang; Xu, Zeping; Ye, Fan; Yang, Jianlun; Ning, Jiamin; Hu, Qingyuan; Zhu, Xuebin

2015-08-01

High energy photons are measured for the first time in wire-array Z-pinch experiments on the Primary Test Stand (PTS) which delivers a current up to 8 MA with a rise time of 70 ns. A special designed detecting system composed of three types of detectors is used to measure the average energy, intensity, and pulse waveform of high energy photons. Results from Pb-TLD (thermoluminescence dosimeter) detector indicate that the average energy is 480 keV (±15%). Pulse shape of high energy photons is measured by the photodiode detector consisted of scintillator coupled with a photodiode, and it is correlated with soft x-ray power by the same timing signal. Intensity is measured by both TLD and the photodiode detector, showing good accordance with each other, and it is 1010 cm-2 (±20%) at 2 m in the horizontal direction. Measurement results show that high energy photons are mainly produced in pinch regions due to accelerated electrons. PTS itself also produces high energy photons due to power flow electrons, which is one order smaller in amplitude than those from pinch region.

Measurements of high energy photons in Z-pinch experiments on primary test stand.

PubMed

Si, Fenni; Zhang, Chuanfei; Xu, Rongkun; Yuan, Xi; Huang, Zhanchang; Xu, Zeping; Ye, Fan; Yang, Jianlun; Ning, Jiamin; Hu, Qingyuan; Zhu, Xuebin

2015-08-01

High energy photons are measured for the first time in wire-array Z-pinch experiments on the Primary Test Stand (PTS) which delivers a current up to 8 MA with a rise time of 70 ns. A special designed detecting system composed of three types of detectors is used to measure the average energy, intensity, and pulse waveform of high energy photons. Results from Pb-TLD (thermoluminescence dosimeter) detector indicate that the average energy is 480 keV (±15%). Pulse shape of high energy photons is measured by the photodiode detector consisted of scintillator coupled with a photodiode, and it is correlated with soft x-ray power by the same timing signal. Intensity is measured by both TLD and the photodiode detector, showing good accordance with each other, and it is 10(10) cm(-2) (±20%) at 2 m in the horizontal direction. Measurement results show that high energy photons are mainly produced in pinch regions due to accelerated electrons. PTS itself also produces high energy photons due to power flow electrons, which is one order smaller in amplitude than those from pinch region.

Determining timing of Alaska Range exhumation and glaciation through cosmogenic nuclide burial dating.

NASA Astrophysics Data System (ADS)

Sortor, R. N.; Goehring, B. M.; Bemis, S. P.; Ruleman, C.; Nichols, K. A.; Ward, D. J.; Frothingham, M.

2017-12-01

The Alaska Range is a transpressional orogen with modern exhumation initiating 6 Ma. The stratigraphic record of unroofing and uplift of the foreland basin is largely preserved along the northern flank of the Alaska Range in the Pliocene-Pleistocene aged Nenana Gravel, an extensive alluvial fan and braidplain deposit. Chronometric control on the Nenana Gravel is largely lacking, with the limited available age control based on a single Ar-Ar tephra date in an underlying unit and via stratigraphic inferences for the upper portions. Higher-resolution dating of the Nenana Gravel unit is imperative in order to quantify deposition rates and the timing of uplift and deformation of the foreland basin. Furthermore, a glacial unit has been found to lie unconformably on top of the unit at Suntrana Creek and may represent the initiation of glacial advances in the Alaska Range. We present a suite of 26Al/10Be cosmogenic nuclide burial ages collected from the lower, middle, and upper sections of the Nenana Gravel at Suntrana Creek, as well as the overlying glacial unit. Three samples from the lower Nenana Gravel yield an isochron burial age of 4.42+0.67/-0.13 Ma, which represents initiation of Nenana Gravel deposition and may equate to early unroofing of the Alaska Range. Two samples collected from the middle of the Nenana Gravel unit produced an average simple burial age of 2.25+/-0.45 Ma, with a single sample stratigraphically above dating to 0.99 +/-1.60. Two samples from the upper-most portion of the Nenana Gravel yielded an average simple burial age of 1.27+/-0.22 Ma, and one sample from the glacial unit overlying the Nenana Gravel was dated to 0.97+/-0.06 Ma, representing one of the earliest glacial advances in the region. In addition, the age of the glacial unit provides a minimum age for inception of foreland basin uplift and abandonment of the Nenana Gravel in this region.

Increase in the energy density of the pinch plasma in 3D implosion of quasi-spherical wire arrays

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

Aleksandrov, V. V., E-mail: alexvv@triniti.ru; Gasilov, V. A.; Grabovski, E. V.

Results are presented from experimental studies of the characteristics of the soft X-ray (SXR) source formed in the implosion of quasi-spherical arrays made of tungsten wires and metalized kapron fibers. The experiments were carried out at the Angara-5-1 facility at currents of up to 3 MA. Analysis of the spatial distribution of hard X-ray emission with photon energies above 20 keV in the pinch images taken during the implosion of quasi-spherical tungsten wire arrays (QTWAs) showed that a compact quasi-spherical plasma object symmetric with respect to the array axis formed in the central region of the array. Using a diffractionmore » grazing incidence spectrograph, spectra of SXR emission with wavelengths of 20–400 Å from the central, axial, and peripheral regions of the emission source were measured with spatial resolutions along the array radius and height in the implosion of QTWAs. It is shown that the emission spectra of the SXR sources formed under the implosion of quasi-spherical and cylindrical tungsten wire arrays at currents of up to 3 MA have a maximum in the wavelength range of 50–150 Å. It is found that, during the implosion of a QTWA with a profiled linear mass, a redistribution of energy in the emission spectrum takes place, which indicates that, during 3D implosion, the energy of longitudinal motion of the array material additionally contributes to the radiation energy. It is also found that, at close masses of the arrays and close values of the current in the range of 2.4{sup −3} MA, the average energy density in the emission source formed during the implosion of a quasi-spherical wire array is larger by a factor of 7 than in the source formed during the implosion of a cylindrical wire array. The experimental data were compared with results of 3D simulations of plasma dynamics and radiation generation during the implosion of quasi-spherical wire arrays with a profiled mass by using the MARPLE-3D radiative magnetohydrodynamic code, developed at the Keldysh Institute of Applied Mathematics, Russian Academy of Sciences.« less

Advantages of conducting in-situ U-Pb age dating of multiple U-bearing minerals from a single complex: Case in point - the Oka Carbonatite Complex

NASA Astrophysics Data System (ADS)

Chen, W.; Simonetti, A.

2012-12-01

A detailed radiometric investigation is currently underway focusing on U-bearing accessory minerals apatite, perovskite, and niocalite from the Oka Carbonatite Complex (Canada). One of the main objectives is to obtain a comparative chronology of melt crystallization for the complex. Unlike other commonly adopted U-bearing minerals (e.g., zircon, monazite) for in-situ dating investigations, apatite, perovskite, and niocalite contain relatively high contents of common Pb. Hence, careful assessment of the proportion and composition of the common Pb, and usage of appropriate matrix-matched external standards are imperative. The Madagascar apatite was utilized as the external standard for apatite dating, and the Emerald Lake and Durango apatites were adopted as secondary standards; the latter yield ages of 92.6 ±1.8 and 32.2 ±1.1 Ma, respectively, and these are identical to their accepted ages. Pb/U ages for apatite from Oka were obtained for different rock types, including 8 carbonatites, 4 okaites, 3 ijolites and 3 alnoites, and these define a range of ages between ~105 and ~135 Ma; this result suggests a protracted crystallization history. In total, 266 individual analyses define two peaks at ~115 and ~125Ma. For perovskite dating, the Ice River perovskite standard was utilized as the external standard. The perovskites from one okaite sample yield an age of 112.2 ±1.9 Ma, and is much younger than the previously reported U-Pb perovskite age of 131 ±7 Ma. Hence, the combined U-Pb perovskite ages also suggest a rather prolonged time of melt crystallization. Niocalite is a rare, accessory silicate mineral that occurs within the carbonatites at Oka. The international zircon standard BR266 was selected for use as the external standard and rastering was employed to minimize the Pb-U fractionation. Two niocalite samples give young ages at 110.6 ±1.2 and 115.0 ±1.9 Ma, and are identical to their respective apatite ages (given associated uncertainties) from the same sample. The niocalite for a carbonatite sample Oka153 defines a bimodal age distribution, with weighted average 206Pb/238U ages of 110.1 ±5.0 and 133.2 ±6.1 Ma. Apatite from the same sample also records a similar bimodal age distribution of 111.4 ±2.8 and 126.9 ±1.8 Ma. The combined in situ U-Pb dating results for apatite, pervoskite, niocalite from Oka clearly support a protracted history of magmatic activity (~30 Myr) for this carbonatite complex. Of importance, the U-Pb results from this study clearly indicate the significance of conducting a thorough geochronological investigation rather than defining the age of any one alkaline complex solely on the basis of a single radiometric age determination.

MaGa, a web-based collaborative database for gas emissions: a tool to improve the knowledge on Earth degassing

NASA Astrophysics Data System (ADS)

Frigeri, A.; Cardellini, C.; Chiodini, G.; Frondini, F.; Bagnato, E.; Aiuppa, A.; Fischer, T. P.; Lehnert, K. A.

2014-12-01

The study of the main pathways of carbon flux from the deep Earth requires the analysis of a large quantity and variety of data on volcanic and non-volcanic gas emissions. Hence, there is need for common frameworks to aggregate available data and insert new observations. Since 2010 we have been developing the Mapping Gas emissions (MaGa) web-based database to collect data on carbon degassing form volcanic and non-volcanic environments. MaGa uses an Object-relational model, translating the experience of field surveyors into the database schema. The current web interface of MaGa allows users to browse the data in tabular format or by browsing an interactive web-map. Enabled users can insert information as measurement methods, instrument details as well as the actual values collected in the field. Measurements found in the literature can be inserted as well as direct field observations made by human-operated instruments. Currently the database includes fluxes and gas compositions from active craters degassing, diffuse soil degassing and fumaroles both from dormant volcanoes and open-vent volcanoes from literature survey and data about non-volcanic emission of the Italian territory. Currently, MaGa holds more than 1000 volcanic plume degassing fluxes, data from 30 sites of diffuse soil degassing from italian volcanoes, and about 60 measurements from fumarolic and non volcanic emission sites. For each gas emission site, the MaGa holds data, pictures, descriptions on gas sampling, analysis and measurement methods, together with bibliographic references and contacts to researchers having experience on each site. From 2012, MaGa developments started to be focused towards the framework of the Deep Earth Carbon Degassing research initiative of the Deep Carbon Observatory. Whithin the DECADE initiative, there are others data systems, as EarthChem and the Smithsonian Institution's Global Volcanism Program. An interoperable interaction between the DECADE data systems is being planned. MaGa is showing good potentials to improve the knowledge on Earth degassing firstly by making data more accessible and encouraging participation among researchers, and secondly by allowing to observe and explore, for the first time, a gas emission dataset with spatial and temporal extents never analyzed before.

A WAO - ARIA - GA²LEN consensus document on molecular-based allergy diagnostics

PubMed Central

2013-01-01

Molecular-based allergy (MA) diagnostics is an approach used to map the allergen sensitization of a patient at a molecular level, using purified natural or recombinant allergenic molecules (allergen components) instead of allergen extracts. Since its introduction, MA diagnostics has increasingly entered routine care, with currently more than 130 allergenic molecules commercially available for in vitro specific IgE (sIgE) testing. MA diagnostics allows for an increased accuracy in allergy diagnosis and prognosis and plays an important role in three key aspects of allergy diagnosis: (1) resolving genuine versus cross-reactive sensitization in poly-sensitized patients, thereby improving the understanding of triggering allergens; (2) assessing, in selected cases, the risk of severe, systemic versus mild, local reactions in food allergy, thereby reducing unnecessary anxiety for the patient and the need for food challenge testing; and (3) identifying patients and triggering allergens for specific immunotherapy (SIT). Singleplex and multiplex measurement platforms are available for MA diagnostics. The Immuno-Solid phase Allergen Chip (ISAC) is the most comprehensive platform currently available, which involves a biochip technology to measure sIgE antibodies against more than one hundred allergenic molecules in a single assay. As the field of MA diagnostics advances, future work needs to focus on large-scale, population-based studies involving practical applications, elucidation and expansion of additional allergenic molecules, and support for appropriate test interpretation. With the rapidly expanding evidence-base for MA diagnosis, there is a need for allergists to keep abreast of the latest information. The aim of this consensus document is to provide a practical guide for the indications, determination, and interpretation of MA diagnostics for clinicians trained in allergology. PMID:24090398

MoO2-ordered mesoporous carbon hybrids as anode materials with highly improved rate capability and reversible capacity for lithium-ion battery.

PubMed

Chen, Ailian; Li, Caixia; Tang, Rui; Yin, Longwei; Qi, Yongxin

2013-08-28

A novel hybrid of MoO2-ordered mesoporous carbon (MoO2-OMC) was prepared through a two-step solvothermal chemical reaction route. The electrochemical performances of the mesoporous MoO2-OMC hybrids were examined using galvanostatical charge-discharge, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) techniques. The MoO2-OMC hybrid exhibits significantly improved electrochemical performance of high reversible capacity, high-rate capability, and excellent cycling performance as an anode electrode material for Li ion batteries. It is revealed that the MoO2-OMC hybrid could deliver the first discharge capacity of 1641.8 mA h g(-1) with an initial Coulombic efficiency of 63.6%, and a reversible capacity as high as 1049.1 mA h g(-1) even after 50 cycles at a current density of 100 mA g(-1), much higher than the theoretical capacity of MoO2 (838 mA h g(-1)) and OMC materials. The MoO2-OMC hybrid demonstrates an excellent high rate capability with capacity of ∼600 mA h g(-1) even at a charge current density of 1600 mA g(-1) after 50 cycles, which is approximately 11.1 times higher than that of the OMC (54 mA h g(-1)) materials. The improved rate capability and reversible capacity of the MoO2-OMC hybrid are attributed to a synergistic reaction between the MoO2 nanoparticles and mesoporous OMC matrices. It is noted that the electrochemical performance of the MoO2-OMC hybrid is evidently much better than the previous MoO2-based hybrids.

A WAO - ARIA - GA²LEN consensus document on molecular-based allergy diagnostics.

PubMed

Canonica, Giorgio Walter; Ansotegui, Ignacio J; Pawankar, Ruby; Schmid-Grendelmeier, Peter; van Hage, Marianne; Baena-Cagnani, Carlos E; Melioli, Giovanni; Nunes, Carlos; Passalacqua, Giovanni; Rosenwasser, Lanny; Sampson, Hugh; Sastre, Joaquin; Bousquet, Jean; Zuberbier, Torsten

2013-10-03

Molecular-based allergy (MA) diagnostics is an approach used to map the allergen sensitization of a patient at a molecular level, using purified natural or recombinant allergenic molecules (allergen components) instead of allergen extracts. Since its introduction, MA diagnostics has increasingly entered routine care, with currently more than 130 allergenic molecules commercially available for in vitro specific IgE (sIgE) testing.MA diagnostics allows for an increased accuracy in allergy diagnosis and prognosis and plays an important role in three key aspects of allergy diagnosis: (1) resolving genuine versus cross-reactive sensitization in poly-sensitized patients, thereby improving the understanding of triggering allergens; (2) assessing, in selected cases, the risk of severe, systemic versus mild, local reactions in food allergy, thereby reducing unnecessary anxiety for the patient and the need for food challenge testing; and (3) identifying patients and triggering allergens for specific immunotherapy (SIT).Singleplex and multiplex measurement platforms are available for MA diagnostics. The Immuno-Solid phase Allergen Chip (ISAC) is the most comprehensive platform currently available, which involves a biochip technology to measure sIgE antibodies against more than one hundred allergenic molecules in a single assay. As the field of MA diagnostics advances, future work needs to focus on large-scale, population-based studies involving practical applications, elucidation and expansion of additional allergenic molecules, and support for appropriate test interpretation. With the rapidly expanding evidence-base for MA diagnosis, there is a need for allergists to keep abreast of the latest information. The aim of this consensus document is to provide a practical guide for the indications, determination, and interpretation of MA diagnostics for clinicians trained in allergology.

New U-Pb zircon ages and the duration and division of Devonian time

USGS Publications Warehouse

Tucker, R.D.; Bradley, D.C.; Ver Straeten, C.A.; Harris, A.G.; Ebert, J.R.; McCutcheon, S.R.

1998-01-01

Newly determined U-Pb zircon ages of volcanic ashes closely tied to biostratigraphic zones are used to revise the Devonian time-scale. They are: 1) 417.6 ?? 1.0 Ma for an ash within the conodont zone of Icriodus woschmidti/I. w. hesperius Lochkovian); 2) 408.3 ?? 1.9 Ma for an ash of early Emsian age correlated with the conodont zones of Po. dehiscens--Lower Po. inversus; 3) 391.4 ?? 1.8 Ma for an ash within the Po. c. costatus Zone and probably within the upper half of the zone (Eifelian); and 4) 381.1 ?? 1.3 Ma for an ash within the range of the Frasnian conodont Palmatolepis punctata (Pa. punctata Zone to Upper Pa. hassi Zone). U-Pb zircon ages for two rhyolites bracketing a palyniferous bed of the pusillites-lepidophyta spore zone, are dated at 363.8 ?? 2.2 Ma and 363 ?? 2.2 Ma and 363.4 ?? 1.8 Ma, respectively, suggesting an age of ~363 Ma for a level within the late Famennian Pa. g. expansa Zone. These data, together with other published zircon ages, suggest that the base and top of the Devonian lie close to 418 Ma and 362 Ma, respectively, thus lengthening the period of ~20% over current estimates. We suggest that the duration of the Middle Devonian (Eifelian and Givitian) is rather brief, perhaps no longer than 11.5 Myr (394 Ma-382.5 Ma), and that the Emsian and Famennian are the longest stages in the period with estimated durations of ~15.5 Myr and 14.5 Myr, respectively.

Gender differences in mathematics anxiety and the relation to mathematics performance while controlling for test anxiety

PubMed Central

2012-01-01

Background Mathematics anxiety (MA), a state of discomfort associated with performing mathematical tasks, is thought to affect a notable proportion of the school age population. Some research has indicated that MA negatively affects mathematics performance and that girls may report higher levels of MA than boys. On the other hand some research has indicated that boys’ mathematics performance is more negatively affected by MA than girls’ performance is. The aim of the current study was to measure girls’ and boys’ mathematics performance as well as their levels of MA while controlling for test anxiety (TA) a construct related to MA but which is typically not controlled for in MA studies. Methods Four-hundred and thirty three British secondary school children in school years 7, 8 and 10 completed customised mental mathematics tests and MA and TA questionnaires. Results No gender differences emerged for mathematics performance but levels of MA and TA were higher for girls than for boys. Girls and boys showed a positive correlation between MA and TA and a negative correlation between MA and mathematics performance. TA was also negatively correlated with mathematics performance, but this relationship was stronger for girls than for boys. When controlling for TA, the negative correlation between MA and performance remained for girls only. Regression analyses revealed that MA was a significant predictor of performance for girls but not for boys. Conclusions Our study has revealed that secondary school children experience MA. Importantly, we controlled for TA which is typically not controlled for in MA studies. Girls showed higher levels of MA than boys and high levels of MA were related to poorer levels of mathematics performance. As well as potentially having a detrimental effect on ‘online’ mathematics performance, past research has shown that high levels of MA can have negative consequences for later mathematics education. Therefore MA warrants attention in the mathematics classroom, particularly because there is evidence that MA develops during the primary school years. Furthermore, our study showed no gender difference in mathematics performance, despite girls reporting higher levels of MA. These results might suggest that girls may have had the potential to perform better than boys in mathematics however their performance may have been attenuated by their higher levels of MA. Longitudinal research is needed to investigate the development of MA and its effect on mathematics performance. PMID:22769743

Gender differences in mathematics anxiety and the relation to mathematics performance while controlling for test anxiety.

PubMed

Devine, Amy; Fawcett, Kayleigh; Szűcs, Dénes; Dowker, Ann

2012-07-09

Mathematics anxiety (MA), a state of discomfort associated with performing mathematical tasks, is thought to affect a notable proportion of the school age population. Some research has indicated that MA negatively affects mathematics performance and that girls may report higher levels of MA than boys. On the other hand some research has indicated that boys' mathematics performance is more negatively affected by MA than girls' performance is. The aim of the current study was to measure girls' and boys' mathematics performance as well as their levels of MA while controlling for test anxiety (TA) a construct related to MA but which is typically not controlled for in MA studies. Four-hundred and thirty three British secondary school children in school years 7, 8 and 10 completed customised mental mathematics tests and MA and TA questionnaires. No gender differences emerged for mathematics performance but levels of MA and TA were higher for girls than for boys. Girls and boys showed a positive correlation between MA and TA and a negative correlation between MA and mathematics performance. TA was also negatively correlated with mathematics performance, but this relationship was stronger for girls than for boys. When controlling for TA, the negative correlation between MA and performance remained for girls only. Regression analyses revealed that MA was a significant predictor of performance for girls but not for boys. Our study has revealed that secondary school children experience MA. Importantly, we controlled for TA which is typically not controlled for in MA studies. Girls showed higher levels of MA than boys and high levels of MA were related to poorer levels of mathematics performance. As well as potentially having a detrimental effect on 'online' mathematics performance, past research has shown that high levels of MA can have negative consequences for later mathematics education. Therefore MA warrants attention in the mathematics classroom, particularly because there is evidence that MA develops during the primary school years. Furthermore, our study showed no gender difference in mathematics performance, despite girls reporting higher levels of MA. These results might suggest that girls may have had the potential to perform better than boys in mathematics however their performance may have been attenuated by their higher levels of MA. Longitudinal research is needed to investigate the development of MA and its effect on mathematics performance.

Current scaling of radiated power for 40-mm diameter single wire arrays on Z

NASA Astrophysics Data System (ADS)

Nash, T. J.; Cuneo, M. E.; Spielman, R. B.; Chandler, G. A.; Leeper, R. J.; Seaman, J. F.; McGurn, J.; Lazier, S.; Torres, J.; Jobe, D.; Gilliland, T.; Nielsen, D.; Hawn, R.; Bailey, J. E.; Lake, P.; Carlson, A. L.; Seamen, H.; Moore, T.; Smelser, R.; Pyle, J.; Wagoner, T. C.; LePell, P. D.; Deeney, C.; Douglas, M. R.; McDaniel, D.; Struve, K.; Mazarakis, M.; Stygar, W. A.

2004-11-01

In order to estimate the radiated power that can be expected from the next-generation Z-pinch driver such as ZR at 28 MA, current-scaling experiments have been conducted on the 20 MA driver Z. We report on the current scaling of single 40 mm diameter tungsten 240 wire arrays with a fixed 110 ns implosion time. The wire diameter is decreased in proportion to the load current. Reducing the charge voltage on the Marx banks reduces the load current. On one shot, firing only three of the four levels of the Z machine further reduced the load current. The radiated energy scaled as the current squared as expected but the radiated power scaled as the current to the 3.52±0.42 power due to increased x-ray pulse width at lower current. As the current is reduced, the rise time of the x-ray pulse increases and at the lowest current value of 10.4 MA, a shoulder appears on the leading edge of the x-ray pulse. In order to determine the nature of the plasma producing the leading edge of the x-ray pulse at low currents further shots were taken with an on-axis aperture to view on-axis precursor plasma. This aperture appeared to perturb the pinch in a favorable manner such that with the aperture in place there was no leading edge to the x-ray pulses at lower currents and the radiated power scaled as the current squared ±0.75. For a full-current shot we will present x-ray images that show precursor plasma emitting on-axis 77 ns before the main x-ray burst.

High frequency pulsed electromigration

NASA Astrophysics Data System (ADS)

Malone, David Wayne

Electromigration life tests were performed on copper-alloyed aluminum test structures that were representative of modern CMOS metallization schemes, complete with Ti/TiN cladding layers and a tungsten-plug contact at the cathode. A total of 18 electrical stress treatments were applied. One was a DC current of 15 mA. The other 17 were pulsed currents, varied according to duty cycle and frequency. The pulse amplitude was 15 mA (˜2.7 × 10sp6 A/cmsp2) for all treatments. Duty cycles ranged from 33.3% to 80%, and frequencies fell into three rough ranges-100 KHz, 1 MHz, and 100 MHz. The ambient test temperature was 200sp°C in all experiments. Six to 9 samples were subjected to each treatment. Experimental data were gathered in the form of test stripe resistance versus time, R(t). For purposes of lifetime analysis, "failure" was defined by the criterion R(t)/R(0) = 1.10, and the median time to failure, tsb{50}, was used as the primary basis of comparison between test groups. It was found that the dependence of tsb{50} on pulse duty cycle conformed rather well to the so-called "average current density model" for duty cycles of 50% and higher. Lifetimes were less enhanced for a duty cycle of 33.3%, but they were still considerably longer than an "on-time" model would predict. No specific dependence of tsb{50} on pulse frequency was revealed by the data, that is, reasonably good predictions of tsb{50} could be made by recognizing the dominant influence of duty cycle. These findings confirm that IC miniaturization can be more aggressively pursued than an on-time prediction would allow. It is significant that this was found to be true for frequencies on the order of 100 MHz, where many present day digital applications operate. Post-test optical micrographs were obtained for each test subject in order to determine the location of electromigration damage. The pulse duty cycle was found to influence the location. Most damage occurred at the cathode contact, regardless of treatment conditions, but there was an increased incidence of damage farther downwind with decreasing duty cycle. This tendency and the deviation from the average current density model for small duty cycles were explained in terms of the Blech length, its dependence on microstructure and duty cycle, and its impact on the relative rates of damage and recovery.

Making Medicare Advantage a Middle-Class Program

PubMed Central

Glazer, Jacob; McGuire, Thomas

2013-01-01

This paper studies the role of Medicare's premium policy in sorting beneficiaries between traditional Medicare (TM) and managed care plans in the Medicare Advantage (MA) program. Beneficiaries vary in their demand for care. TM fully accommodates demand but creates a moral hazard inefficiency. MA rations care but disregards some elements of the demand. We describe an efficient assignment of beneficiaries to these two options, and argue that efficiency requires an MA program oriented to serve the large middle part of the distribution of demand: the “middle class.” Current Medicare policy of a “single premium” for MA plans cannot achieve efficient sorting. We characterize the demand-based premium policy that can implement the efficient assignment of enrollees to plans. If only a single premium is feasible, the second-best policy involves too many of the low-demand individuals in MA and a too low level of services relative to the first best. We identify approaches to using premium policy to revitalize MA and improve the efficiency of Medicare. PMID:23454916

Making Medicare advantage a middle-class program.

PubMed

Glazer, Jacob; McGuire, Thomas G

2013-03-01

This paper studies the role of Medicare's premium policy in sorting beneficiaries between traditional Medicare (TM) and managed care plans in the Medicare advantage (MA) program. Beneficiaries vary in their demand for care. TM fully accommodates demand but creates a moral hazard inefficiency. MA rations care but disregards some elements of the demand. We describe an efficient assignment of beneficiaries to these two options, and argue that efficiency requires an MA program oriented to serve the large middle part of the distribution of demand: the "middle class." Current Medicare policy of a "single premium" for MA plans cannot achieve efficient sorting. We characterize the demand-based premium policy that can implement the efficient assignment of enrollees to plans. If only a single premium is feasible, the second-best policy involves too many of the low-demand individuals in MA and a too low level of services relative to the first best. We identify approaches to using premium policy to revitalize MA and improve the efficiency of Medicare. Copyright © 2012 Elsevier B.V. All rights reserved.

Negative impact of prior influenza vaccination on current influenza vaccination among people infected and not infected in prior season: A test-negative case-control study in Japan.

PubMed

Saito, Nobuo; Komori, Kazuhiro; Suzuki, Motoi; Morimoto, Kounosuke; Kishikawa, Takayuki; Yasaka, Takahiro; Ariyoshi, Koya

2017-01-23

Accumulating evidences indicate that repeated influenza vaccination has negative impact on the vaccine effectiveness (VE). However no published studies considered past influenza infection when assessing the VE of repeated vaccination. Prospective surveillance was conducted from 2009 to 2012 at a community hospital on a small island in Japan. The study included all outpatients with an influenza-like illness (ILI) who attended the hospital, and a rapid diagnostic test (RDT) was used to diagnose influenza A/B infection. The VE of trivalent inactivated influenza vaccine (TIV) against medically attended influenza A (MA-fluA) was estimated using a test-negative case-control study design. The influence of TIV in the prior season on VE in the current season was investigated in the context of MA-fluA during the prior season. During the three influenza seasons, 5838 ILI episodes (4127 subjects) were analysed. Subjects who had an episode of MA-fluA in the prior season were at a significantly lower risk of MA-fluA in the current season (adjusted odds ratio: 0.38, 95% CI: 0.30-0.50). The overall adjusted VE was 28% (95% CI, 14-40). VE was substantially lower in subjects vaccinated in the prior season compared to those who had not been vaccinated in prior season (19%; 95% CI: 0-35 vs 46%; 95% CI: 26-60, test for interaction, P value <0.05). In subjects who did not have MA-fluA in the prior season showed the attenuation of VE due to repeated vaccination (13%; 95% CI: -7 to 30 vs 44%; 95% CI: 24-59, test for interaction, P<0.05). However this effect was not detected in subjects who had contracted MA-fluA in the prior season. Negative effects of repeated vaccination were significant among those without history of MA-fluA in the prior season. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

A 60 mA DC H- multi cusp ion source developed at TRIUMF

NASA Astrophysics Data System (ADS)

Jayamanna, K.; Ames, F.; Bylinskii, I.; Lovera, M.; Minato, B.

2018-07-01

This paper describes the latest high-current multi cusp type ion source developed at TRIUMF, which is capable of producing a negative hydrogen ion beam (H-) of 60 mA of direct current at 140V and 90A arc. The results achieved to date including emittance measurements and filament lifetime issues are presented. The low current version of this ion source is suitable for medical cyclotrons as well as accelerators and the high current version is intended for producing large neutral hydrogen beams for fusion research. The description of the source magnetic configuration, the electron filter profile and the differential pumping techniques given in the paper will allow the building of an arc discharge H- ion source with similar properties.

GaInAsP/InP lateral-current-injection distributed feedback laser with a-Si surface grating.

PubMed

Shindo, Takahiko; Okumura, Tadashi; Ito, Hitomi; Koguchi, Takayuki; Takahashi, Daisuke; Atsumi, Yuki; Kang, Joonhyun; Osabe, Ryo; Amemiya, Tomohiro; Nishiyama, Nobuhiko; Arai, Shigehisa

2011-01-31

We fabricated a novel lateral-current-injection-type distributed feedback (DFB) laser with amorphous-Si (a-Si) surface grating as a step to realize membrane lasers. This laser consists of a thin GaInAsP core layer grown on a semi-insulating InP substrate and a 30-nm-thick a-Si surface layer for DFB grating. Under a room-temperature continuous-wave condition, a low threshold current of 7.0 mA and high efficiency of 43% from the front facet were obtained for a 2.0-μm stripe width and 300-μm cavity length. A small-signal modulation bandwidth of 4.8 GHz was obtained at a bias current of 30 mA.

Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenol Ethers (PBDEs) in Current and Historical Samples of Avian Eggs from Nesting Sites in Buzzards Bay, MA, USA

EPA Science Inventory

We measured concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in eggs from breeding colonies in Buzzards Bay, MA, USA. Eggs from two piscivorous bird species, common (Sterna hirundo) and roseate (Sterna dougallii) terns, were collected...

Evidence for differences in the thermal histories of Antarctic and non-Antarctic H chondrites with cosmic-ray exposure ages less than 20 Ma

NASA Technical Reports Server (NTRS)

Sears, Derek W. G.; Benoit, Paul; Batchelor, J. David

1991-01-01

Antarctic H chondrites show a different range of induced thermoluminescence properties compared with those of H chondrites that have fallen elsewhere in the world. Recent noble gas data of Schultz et al. (1991) show that this difference is displayed most dramatically by meteorites with cosmic-ray exposure ages less than 20 Ma, and they confirm that the differences cannot be attributed to weathering or to the presence of a great many fragments of an unusual Antarctic meteorite. Annealing experiments on an H5 chondrite, and other measurements on a variety of ordinary chondrites, have shown that induced TL properties are sensitive to the thermal histories of the meteorities. It is concluded that the events(s) that released the less than 20 Ma samples, which are predominantly those with exposure ages of 8 + or - 2 Ma, produced two groups with different thermal histories, one that came to earth several 100,000 years ago and that are currently only found in Antarctica, and one that is currently falling on the earth.

Template-free synthesis of vanadium oxides nanobelt arrays as high-rate cathode materials for lithium ion batteries

NASA Astrophysics Data System (ADS)

Qin, Mulan; Liang, Qiang; Pan, Anqiang; Liang, Shuquan; Zhang, Qing; Tang, Yan; Tan, Xiaoping

2014-12-01

A facile hydrothermal route has been developed to fabricate the metastable VO2 (B) ultra-thin nanobelt arrays, which can be converted into V2O5 porous nanobelt arrays after calcinating VO2 (B) in air at 400 °C for 1 h. The influence of hydrothermal time to the crystallinity and morphology of the VO2 phase has been studied. A possible mechanism for the formation of VO2 nanobelt arrays has been proposed in this paper. As a cathode material for lithium ion batteries, the V2O5 nanobelt arrays show excellent rate capability and cycling stability. An initial discharge capacity of 142 mA h g-1 can be delivered at a current density of 50 mA g-1 with almost no capacity fading after 100 cycles. Even at a current density of 1000 mA g-1, they still exhibit the capacity of 130 mA h g-1 and superior capacity retention capability. The excellent electrochemical properties are attributed to the ultra-thin thickness and the porous structures of the nanobelts.

New synthesis of maleic anhydride modified polyolefins and their applications

NASA Astrophysics Data System (ADS)

Lu, Bing

Maleic anhydride (MA) modified polyolefins are the most useful commercial functional polyolefins. The current technology of producing MA modified polyolefins, mainly free radical modification, usually results in low MA graft contents, extensive side reactions, and poor control of graft structures. In this thesis, we show a new synthetic route for preparing MA modified polyolefins with excellent control of polymer structures and MA concentrations. The synthesis is based on the "reactive" polyolefin copolymers, i.e. polyolefins containing p-methylstyrene or alkylborane groups. The p-methylstyrene copolymers lead to selectively grafting reactions on the p-methyl groups, greatly reducing the side reactions on the polyolefin backbone. The MA graft content was proportional to the concentration of p-methylstyrene. In the borane approach, under controlled selective oxidation, the alkylborane containing PP polymers formed the "stable" polymeric radical in situ which initiated the graft-from reaction. By varying the monomer concentrations of MA and styrene, reaction time and temperature, a broad range of MA modified PP polymers were prepared from a single MA terminated or grafted PP to a very long SMA segment blocked or grafted PP, and there is no detectable side reaction on the PP backbone. MA modified polyolefins were investigated in the applications of glass fiber reinforced PP, elastomer toughened Nylon, and polyolefin/Nylon blends. The MA modified polyolefin compatibilizers showed the significant improved mechanical properties and morphology of the blends. The effectiveness of compatibilization depends on the MA concentration, molecular weight of the polyolefin segments, the structure of the compatibilizers, and the composition of the blend. By amidation or imidation reaction of MA modified PP with amine terminated PP, long chain branched PP polymers were also prepared. The results of IR, GPC, intrinsic viscosity and DSC studies clearly indicate the formation of long chain branched PP.

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

Esswein, AJ; Surendranath, Y; Reece, SY

A high surface area electrode is functionalized with cobalt-based oxygen evolving catalysts (Co-OEC = electrodeposited from pH 7 phosphate, Pi, pH 8.5 methylphosphonate, MePi, and pH 9.2 borate electrolyte, Bi). Co-OEC prepared from MePi and operated in Pi and Bi achieves a current density of 100 mA cm(-2) for water oxidation at 442 and 363 mV overpotential, respectively. The catalyst retains activity in near-neutral pH buffered electrolyte in natural waters such as those from the Charles River (Cambridge, MA) and seawater (Woods Hole, MA). The efficacy and ease of operation of anodes functionalized with Co-OEC at appreciable current density togethermore » with its ability to operate in near neutral pH buffered natural water sources bodes well for the translation of this catalyst to a viable renewable energy storage technology.« less

Neural control of rhythmic arm cycling after stroke

PubMed Central

Loadman, Pamela M.; Hundza, Sandra R.

2012-01-01

Disordered reflex activity and alterations in the neural control of walking have been observed after stroke. In addition to impairments in leg movement that affect locomotor ability after stroke, significant impairments are also seen in the arms. Altered neural control in the upper limb can often lead to altered tone and spasticity resulting in impaired coordination and flexion contractures. We sought to address the extent to which the neural control of movement is disordered after stroke by examining the modulation pattern of cutaneous reflexes in arm muscles during arm cycling. Twenty-five stroke participants who were at least 6 mo postinfarction and clinically stable, performed rhythmic arm cycling while cutaneous reflexes were evoked with trains (5 × 1.0-ms pulses at 300 Hz) of constant-current electrical stimulation to the superficial radial (SR) nerve at the wrist. Both the more (MA) and less affected (LA) arms were stimulated in separate trials. Bilateral electromyography (EMG) activity was recorded from muscles acting at the shoulder, elbow, and wrist. Analysis was conducted on averaged reflexes in 12 equidistant phases of the movement cycle. Phase-modulated cutaneous reflexes were present, but altered, in both MA and LA arms after stroke. Notably, the pattern was “blunted” in the MA arm in stroke compared with control participants. Differences between stroke and control were progressively more evident moving from shoulder to wrist. The results suggest that a reduced pattern of cutaneous reflex modulation persists during rhythmic arm movement after stroke. The overall implication of this result is that the putative spinal contributions to rhythmic human arm movement remain accessible after stroke, which has translational implications for rehabilitation. PMID:22572949

Associations of Sugar and Artificially Sweetened Soda with Albuminuria and Kidney Function Decline in Women

PubMed Central

Curhan, Gary C.

2011-01-01

Summary Background and objectives Sugar-sweetened soda is reported to be associated with increased risk for diabetes and albuminuria, but there are currently limited data on how sugar or artificially sweetened soda may be related to kidney function decline. Design, setting, participants, & measurements This study identified 3318 women participating in the Nurses' Health Study with data on soda intake and albuminuria; of these, 3256 also had data on estimated GFR (eGFR) change between 1989 and 2000. Cumulative average beverage intake was derived from the 1984, 1986, 1990, 1994, and 1998 food frequency questionnaires. Serving categories included <1/mo (referent), 1 to 4/mo, 2 to 6/wk, 1 to 1.9/d, and ≥2/d. Microalbuminuria (MA) was considered a urinary albumin-to-creatinine ratio of 25 to 355 μg/mg. For kidney function change, the primary outcome was a ≥30% decline in eGFR over 11 years; rapid eGFR decline defined as ≥3 ml/min per 1.73 m2 per year was also examined. Results Consumption of ≥2 servings per day of artificially sweetened (diet) soda was independently associated with eGFR decline ≥30% (OR 2.02, 95% CI 1.36 to 3.01) and ≥3 ml/min per 1.73 m2 per year (OR 2.20, 95% CI 1.36 to 3.55). No increased risk for eGFR decline was observed for <2 servings per day of diet soda. No associations were noted between diet soda and MA or sugar soda and MA or eGFR decline. Conclusions Consumption of ≥2 servings per day of artificially sweetened soda is associated with a 2-fold increased odds for kidney function decline in women. PMID:20884773

Associations of sugar and artificially sweetened soda with albuminuria and kidney function decline in women.

PubMed

Lin, Julie; Curhan, Gary C

2011-01-01

Sugar-sweetened soda is reported to be associated with increased risk for diabetes and albuminuria, but there are currently limited data on how sugar or artificially sweetened soda may be related to kidney function decline. This study identified 3318 women participating in the Nurses' Health Study with data on soda intake and albuminuria; of these, 3256 also had data on estimated GFR (eGFR) change between 1989 and 2000. Cumulative average beverage intake was derived from the 1984, 1986, 1990, 1994, and 1998 food frequency questionnaires. Serving categories included <1/mo (referent), 1 to 4/mo, 2 to 6/wk, 1 to 1.9/d, and ≥ 2/d. Microalbuminuria (MA) was considered a urinary albumin-to-creatinine ratio of 25 to 355 μg/mg. For kidney function change, the primary outcome was a ≥ 30% decline in eGFR over 11 years; rapid eGFR decline defined as ≥ 3 ml/min per 1.73 m(2) per year was also examined. Consumption of ≥ 2 servings per day of artificially sweetened (diet) soda was independently associated with eGFR decline ≥ 30% (OR 2.02, 95% CI 1.36 to 3.01) and ≥ 3 ml/min per 1.73 m(2) per year (OR 2.20, 95% CI 1.36 to 3.55). No increased risk for eGFR decline was observed for <2 servings per day of diet soda. No associations were noted between diet soda and MA or sugar soda and MA or eGFR decline. Consumption of ≥ 2 servings per day of artificially sweetened soda is associated with a 2-fold increased odds for kidney function decline in women.

Sn4+x P3 @ amorphous Sn-P composites as anodes for sodium-ion batteries with low cost, high capacity, long life, and superior rate capability.

PubMed

Li, Weijie; Chou, Shu-Lei; Wang, Jia-Zhao; Kim, Jung Ho; Liu, Hua-Kun; Dou, Shi-Xue

2014-06-25

Sn4+x P3 @ amorphous Sn-P composites are a promising cheap anode material for sodium-ion batteries with high capacity (502 mA h g(-1) at a current density of 100 mA g(-1)), long cycling stability (92.6% capacity retention up to 100 cycles), and high rate capability (165 mA h g(-1) at the 10C rate). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

BioMaS: a modular pipeline for Bioinformatic analysis of Metagenomic AmpliconS.

PubMed

Fosso, Bruno; Santamaria, Monica; Marzano, Marinella; Alonso-Alemany, Daniel; Valiente, Gabriel; Donvito, Giacinto; Monaco, Alfonso; Notarangelo, Pasquale; Pesole, Graziano

2015-07-01

Substantial advances in microbiology, molecular evolution and biodiversity have been carried out in recent years thanks to Metagenomics, which allows to unveil the composition and functions of mixed microbial communities in any environmental niche. If the investigation is aimed only at the microbiome taxonomic structure, a target-based metagenomic approach, here also referred as Meta-barcoding, is generally applied. This approach commonly involves the selective amplification of a species-specific genetic marker (DNA meta-barcode) in the whole taxonomic range of interest and the exploration of its taxon-related variants through High-Throughput Sequencing (HTS) technologies. The accessibility to proper computational systems for the large-scale bioinformatic analysis of HTS data represents, currently, one of the major challenges in advanced Meta-barcoding projects. BioMaS (Bioinformatic analysis of Metagenomic AmpliconS) is a new bioinformatic pipeline designed to support biomolecular researchers involved in taxonomic studies of environmental microbial communities by a completely automated workflow, comprehensive of all the fundamental steps, from raw sequence data upload and cleaning to final taxonomic identification, that are absolutely required in an appropriately designed Meta-barcoding HTS-based experiment. In its current version, BioMaS allows the analysis of both bacterial and fungal environments starting directly from the raw sequencing data from either Roche 454 or Illumina HTS platforms, following two alternative paths, respectively. BioMaS is implemented into a public web service available at https://recasgateway.ba.infn.it/ and is also available in Galaxy at http://galaxy.cloud.ba.infn.it:8080 (only for Illumina data). BioMaS is a friendly pipeline for Meta-barcoding HTS data analysis specifically designed for users without particular computing skills. A comparative benchmark, carried out by using a simulated dataset suitably designed to broadly represent the currently known bacterial and fungal world, showed that BioMaS outperforms QIIME and MOTHUR in terms of extent and accuracy of deep taxonomic sequence assignments.

Application of Arrester Simulation Device in Training

NASA Astrophysics Data System (ADS)

Baoquan, Zhang; Ziqi, Chai; Genghua, Liu; Wei, Gao; Kaiyue, Wu

2017-12-01

Combining with the arrester simulation device put into use successfully, this paper introduces the application of arrester test in the insulation resistance measurement, counter test, Leakage current test under DC 1mA voltage and leakage current test under 0.75U1mA. By comparing with the existing training, this paper summarizes the arrester simulation device’s outstanding advantages including real time monitoring, multi-type fault data analysis and acousto-optic simulation. It effectively solves the contradiction between authenticity and safety in the existing test training, and provides a reference for further training.

An Efficient Energy Management Strategy, Unique Power Split & Energy Distribution, Based on Calculated Vehicle Road Loads

DTIC Science & Technology

2012-08-01

HMMWV for the current given inputs based on the current vehicle speed, acceleration pedal , and brake pedal . From this driver requested power at the...HMMWV engine, b) base HMMWV gear ratios of the 4 speed transmission, c) acceleration and brake pedal pressed for the hybrid vehicle and d) Torque...coefficient. µb: Threshold for detecting brake pedal pressed ? 2 tanE4FGH 2 tanE4 I [K ρ: Air mass density, ρ = ma/Va where ma is mass of air

Bottom current deposition in the Antarctic Wilkes Land margin during the Oligocene

NASA Astrophysics Data System (ADS)

Salabarnada, Ariadna; Escutia, Carlota; Nelson, Hans C.; Evangelinos, Dimitris; López-Quirós, Adrián

2017-04-01

Sediment cores collected from the Antarctic Wilkes Land continental rise at IODP site 1356 provide evidence for bottom current sedimentation taking place since the early Oligocene (i.e., 33.6 Ma) (Escutia et al., 2011). Correlation between site 1356 sediments and the regional grid of multichannel seismic reflection profiles, complemented with bathymetric data, allow us to differentiate a variety of contourite deposits resulting from the interaction between bottom currents and seafloor paleomorphologies. Contourite deposits are identified based on the seismic signature, reflector configuration and geometry of the depositional bodies as elongated-mounded drifts, giant mounded drifts, confined drifts, infill drifts, plastered drifts, sediment waves, and moats. Based on the spatial and temporal distribution of these deposits, we differentiate three phases in contourite deposition in this margin: Phase 1) from 33.6-28 Ma sheeted drift morphologies dominate, related to high-energy deposits associated with fast flowing currents during the early Oligocene; Phase 2) At around 28 Ma, mounded drift morphologies and moat channels start forming. Continued intensification of contour currents results in larger contourite morphologies such as giant mounded drifts and moats forming around structural heights present in the Wilkes Land basin (e.g, the Adelie Rift Block). Phase 3) A shift in current configuration is recorded at around 15 Ma above regional unconformity WL-U5, which marks the Oligocene-Miocene Transition. This change is shown by a migration to the North of the drift crests and by a dominance of down-slope sedimentation processes that is indicated by mass transport deposits and channel levee formation. We interpret the evolution of the contourite deposits during the Oligocene in this margin to be driven by changes in the intensity of bottom current activity over time resulting from ice sheet growth, evolution of bottom morphology and related changes in paleoceanographic configuration in the Southern Ocean. This contribution results from work funded by the Spanish Ministry of Economy and Competitivity Grant CTM2014-60451-C2-1-P and FEDER funds.

PAVE PAWS Early Warning Radar Operation Cape Cod Air Force Station, MA. Record of Decision

DTIC Science & Technology

2009-06-01

Electrical and Electronics Engineers (IEEE) C95.1-1999. Accordingly, the highest measurement was obtained directly in front of the feedhorn (i.e...waveform characterization of the Cape Cod AFS Pave PAWS radar. The data acquired during the Phase IV survey indicated that the electric fields produced...level observed among the ambient sites. During this survey, peak/average power density measurements and peak/average electric field measurements

Time course of pentacyclic triterpenoids from fruits and leaves of olive tree (Olea europaea L.) cv. Picual and cv. Cornezuelo during ripening.

PubMed

Peragón, Juan

2013-07-10

Pentacyclic triterpenoids are plant secondary metabolites of great interest for health and disease prevention. HPLC-UV/vis was used to determine the concentration of the pentacyclic triterpenoids present in fruits and leaves of Picual and Cornezuelo olive tree cultivars. Maslinic acid (MA) and oleanolic acid (OA) are the only two compounds present in fruits, MA being the more abundant. In leaves, in addition to MA and OA, uvaol (UO), and erythrodiol (EO) are found, with OA being the most abundant. In this work, the changes in the concentrations of these compounds during ripening as well as the effect of Jaén-style table-olive processing are reported. The amount of MA and OA found in Picual and Cornezuelo olives after processing was 1.26 ± 0.06, 1.30 ± 0.06, 0.31 ± 0.02, and 0.23 ± 0.01 mg per fruit, respectively. These results enable us to calculate the average intake of pentacyclic triterpenoids and reinforce the importance of table olives as a source of healthy compounds.

UVER and UV index at high altitude in Northwestern Argentina.

PubMed

Utrillas, M P; Marín, M J; Esteve, A R; Salazar, G; Suarez, H; Castillo, J; Martínez-Lozano, J A

2016-10-01

Measurements of ultraviolet erythemal radiation (UVER) made during two years at three sites located at altitudes over 1000ma.s.l. in Northwestern Argentina (Salta, San Carlos, and El Rosal) have been used to estimate and analyze the UV Index (UVI) and the cumulative doses at these locations. For the UVER irradiance, data of January (maximum values) and June (minimum values) have been analyzed as representative of the year for all locations. The UVI reaches extreme (>11) values in >20% of the analyzed days in Salta (1190ma.s.l.), while these are reached in San Carlos (1611ma.s.l.) and El Rosal (3355ma.s.l.) in >40% of the analyzed days. Finally, the cumulative doses over an average year have also been studied for each location. The doses received during austral summer and autumn are of the same order, and represent one third of the annual dose, while the doses received during austral winter and spring represent one sixth of the annual dose approximately. Copyright © 2016 Elsevier B.V. All rights reserved.

Experimental evidence of ion-induced instabilities in the NSLS-II storage ring

DOE PAGES

Cheng, Weixing; Li, Yongjun; Podobedov, Boris

2017-03-12

Fast ion instability has been identified as one of the most prominent instabilities in the recently constructed NSLS-II storage ring at Brookhaven National Laboratory. At a relatively low beam current (~ 25 mA) multi-bunch fills, ion-induced instabilities have already been observed during the early stages of machine commissioning. At present user operation with 250 mA in ~1000 bunches, the fast ion still remains the dominant instability, even after months of vacuum conditioning at high current. Ion-induced dipole motions of the electron beam have been suppressed using the transverse bunch-by-bunch (BxB) feedback system. However other adverse effects of this instability, suchmore » as the vertical beam size increase along the bunch train cannot be cured by the feedback system. Therefore, to achieve the NSLS-II design current of 500 mA while maintaining a small vertical beam emittance, it is important to further understand the fast ion instability and develop mitigation techniques. This paper reports on a series of ion-instability observations at various fill patterns and beam currents using start-of-art NSLS-II diagnostic tools.« less

Experimental evidence of ion-induced instabilities in the NSLS-II storage ring

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

Cheng, Weixing; Li, Yongjun; Podobedov, Boris

Fast ion instability has been identified as one of the most prominent instabilities in the recently constructed NSLS-II storage ring at Brookhaven National Laboratory. At a relatively low beam current (~ 25 mA) multi-bunch fills, ion-induced instabilities have already been observed during the early stages of machine commissioning. At present user operation with 250 mA in ~1000 bunches, the fast ion still remains the dominant instability, even after months of vacuum conditioning at high current. Ion-induced dipole motions of the electron beam have been suppressed using the transverse bunch-by-bunch (BxB) feedback system. However other adverse effects of this instability, suchmore » as the vertical beam size increase along the bunch train cannot be cured by the feedback system. Therefore, to achieve the NSLS-II design current of 500 mA while maintaining a small vertical beam emittance, it is important to further understand the fast ion instability and develop mitigation techniques. This paper reports on a series of ion-instability observations at various fill patterns and beam currents using start-of-art NSLS-II diagnostic tools.« less

Compression of an Applied Bz field by a z-pinch onto a Tamped DT Fiber for Inertial Confinement Fusion

NASA Astrophysics Data System (ADS)

Nash, Tom

2009-11-01

Simulations of a z-pinch compressing an applied 100 kG Bz field onto an on-axis DT fiber tamped with beryllium show the field reaching over 100 MG in the tamp, sufficient to confine DT alpha particles and to form a thermal barrier. The barrier allows the DT plasma to burn at a rho*r value as low as 0.045 g/cm^2, and at temperatures over 50 keV for a 63 MA drive current. Driving currents between 21 and 63 MA are considered with cryogenic DT fiber diameters between 600 μm and 1.6 mm. Pinch implosion times are 120 ns with a peak implosion velocity of 35 cm/μs. 1D simulations are of a foil pinch, but for improved stability we propose a nested wire-array. Simulated fusion yields with this system scale as the sixth power of the current, with burn fractions scaling as the fourth power of the current. At 63 MA the simulated yield is 521 MJ from 4.2 mg/cm of DT with a 37% burn fraction at a rho*r of only 0.18 g/cm^2.

Identification of AR(I)MA processes for modelling temporal correlations of GPS observations

NASA Astrophysics Data System (ADS)

Luo, X.; Mayer, M.; Heck, B.

2009-04-01

In many geodetic applications observations of the Global Positioning System (GPS) are routinely processed by means of the least-squares method. However, this algorithm delivers reliable estimates of unknown parameters und realistic accuracy measures only if both the functional and stochastic models are appropriately defined within GPS data processing. One deficiency of the stochastic model used in many GPS software products consists in neglecting temporal correlations of GPS observations. In practice the knowledge of the temporal stochastic behaviour of GPS observations can be improved by analysing time series of residuals resulting from the least-squares evaluation. This paper presents an approach based on the theory of autoregressive (integrated) moving average (AR(I)MA) processes to model temporal correlations of GPS observations using time series of observation residuals. A practicable integration of AR(I)MA models in GPS data processing requires the determination of the order parameters of AR(I)MA processes at first. In case of GPS, the identification of AR(I)MA processes could be affected by various factors impacting GPS positioning results, e.g. baseline length, multipath effects, observation weighting, or weather variations. The influences of these factors on AR(I)MA identification are empirically analysed based on a large amount of representative residual time series resulting from differential GPS post-processing using 1-Hz observation data collected within the permanent SAPOS® (Satellite Positioning Service of the German State Survey) network. Both short and long time series are modelled by means of AR(I)MA processes. The final order parameters are determined based on the whole residual database; the corresponding empirical distribution functions illustrate that multipath and weather variations seem to affect the identification of AR(I)MA processes much more significantly than baseline length and observation weighting. Additionally, the modelling results of temporal correlations using high-order AR(I)MA processes are compared with those by means of first order autoregressive (AR(1)) processes and empirically estimated autocorrelation functions.

Microscopic diffusion anisotropy in the human brain: Age-related changes.

PubMed

Lawrenz, Marco; Brassen, Stefanie; Finsterbusch, Jürgen

2016-11-01

The fractional anisotropy (FA) that can be derived from diffusion tensor imaging (DTI), is ambiguous because it not only depends on the tissue microstructure but also on the axon or fiber orientation distribution within a voxel. Measures of the microscopic diffusion anisotropy, like the microscopic anisotropy index (MA) that can be determined with so-called double-wave-vector (DWV) or double diffusion encoding (DDE) imaging, are independent of this orientation distribution and, thus, offer a more direct and undisguised access to the tissue structure on a cellular or microscopic scale. In this study, FA and MA measurements were performed in a group of aged (>60y), healthy volunteers and compared to the data obtained recently for a group of young (<33y), healthy volunteers to reveal age-related differences. The coefficients-of-variation (CV) determined for the aged group were considerably lower for MA than for FA in average and in most of the 16 ROIs analyzed due to lower between-subject variations of MA. FA differences between the young and the aged group were in line with previous DTI studies. MA was also decreased in the aged group but in more of the 16 ROIs and with a higher significance. Furthermore, MA differences were also observed in frontal brain regions containing fiber crossings that did not reveal significant FA differences, i.e. MA seems to provide a better sensitivity to detect microstructural changes in such regions. In some non-cortical gray matter structures like the putamen, FA was increased but MA was decreased in the aged group which could indicate a coherent fiber orientation in the aged group related to the loss of crossing or fanning fibers. In conclusion, MA not only could improve the detectability of differences of the tissue microstructure but, in conjunction with FA, could also help to identify the underlying changes. Copyright © 2016 Elsevier Inc. All rights reserved.

Intensity dependent effects of transcranial direct current stimulation on corticospinal excitability in chronic spinal cord injury.

PubMed

Murray, Lynda M; Edwards, Dylan J; Ruffini, Giulio; Labar, Douglas; Stampas, Argyrios; Pascual-Leone, Alvaro; Cortes, Mar

2015-04-01

To investigate the effects of anodal transcranial direct current stimulation (a-tDCS) intensity on corticospinal excitability and affected muscle activation in individuals with chronic spinal cord injury (SCI). Single-blind, randomized, sham-controlled, crossover study. Medical research institute and rehabilitation hospital. Volunteers (N = 9) with chronic SCI and motor dysfunction in wrist extensor muscles. Three single session exposures to 20 minutes of a-tDCS (anode over the extensor carpi radialis [ECR] muscle representation on the left primary motor cortex, cathode over the right supraorbital area) using 1 mA, 2 mA, or sham stimulation, delivered at rest, with at least 1 week between sessions. Corticospinal excitability was assessed with motor-evoked potentials (MEPs) from the ECR muscle using surface electromyography after transcranial magnetic stimulation. Changes in spinal excitability, sensory threshold, and muscle strength were also investigated. Mean MEP amplitude significantly increased by approximately 40% immediately after 2mA a-tDCS (pre: 0.36 ± 0.1 mV; post: 0.47 ± 0.11 mV; P = .001), but not with 1 mA or sham. Maximal voluntary contraction measures remained unaltered across all conditions. Sensory threshold significantly decreased over time after 1mA (P = .002) and 2mA (P = .039) a-tDCS and did not change with sham. F-wave persistence showed a nonsignificant trend for increase (pre: 32% ± 12%; post: 41% ± 10%; follow-up: 46% ± 12%) after 2 mA stimulation. No adverse effects were reported with any of the experimental conditions. The a-tDCS can transiently raise corticospinal excitability to affected muscles in patients with chronic SCI after 2 mA stimulation. Sensory perception can improve with both 1 and 2 mA stimulation. This study gives support to the safe and effective use of a-tDCS using small electrodes in patients with SCI and highlights the importance of stimulation intensity. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Using transdermal iontophoresis to increase granisetron delivery across skin in vitro and in vivo: effect of experimental conditions and a comparison with other enhancement strategies.

PubMed

Cázares-Delgadillo, Jennyfer; Ganem-Rondero, Adriana; Quintanar-Guerrero, David; López-Castellano, Alicia C; Merino, Virginia; Kalia, Yogeshvar N

2010-03-18

The objectives of the study were (i) to investigate the effect of experimental parameters on the iontophoretic transport of granisetron, (ii) to identify the relative contributions of electromigration (EM) and electroosmosis (EO), (iii) to determine the feasibility of delivering therapeutic amounts of drug for the treatment of chemotherapy-induced nausea and vomiting and (iv) to test the in vitro results in a simple animal model in vivo. Preliminary in vitro studies using aqueous granisetron formulations investigating the effect of drug concentration (5, 10, 20 and 40 mM) and current density (0.1, 0.2, 0.3 mA cm(-2)) were performed using porcine ear skin. As expected, cumulative delivery in vitro at the 20 and 40 mM concentrations was significantly greater than that at 5 and 10mM, which were not statistically different (p<0.05). Increasing the applied current density from 0.1 to 0.3 mA cm(-2) resulted in a approximately 4.2-fold increase in iontophoretic flux. Furthermore, in the absence of Na(+) in the formulation, no dependence of iontophoretic flux on drug concentration was reported (at a granisetron concentration of 40 mM, the transport rate was 2.93+/-0.62 microg cm(-2)min(-1)). Co-iontophoresis of acetaminophen was used to show that EM was the predominant transport mechanism accounting for 71-86% of total granisetron delivery. In vivo studies in Wistar rats (40 mM granisetron; application of 0.3 mA cm(-2) for 5h with Ag/AgCl electrodes and salt bridges) showed an average iontophoretic input rate (k(input)) of 0.83+/-0.26 microg min(-1) and a maximum plasma concentration (C(max)) of 0.092+/-0.004 microg ml(-1). Based on these results and given the known pharmacokinetics, transdermal iontophoresis could achieve therapeutic drug levels for the management of chemotherapy-induced emesis using a reasonably sized (4-6 cm(2)) patch. Copyright 2010 Elsevier B.V. All rights reserved.

Ramp compression of a metallic liner driven by a shaped 5 MA current on the SPHINX machine

NASA Astrophysics Data System (ADS)

d'Almeida, T.; Lassalle, F.; Morell, A.; Grunenwald, J.; Zucchini, F.; Loyen, A.; Maysonnave, T.; Chuvatin, A.

2014-05-01

SPHINX is a 6MA, 1-us Linear Transformer Driver operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. A method for performing magnetic ramp compression experiments was developed using a compact Dynamic Load Current Multiplier inserted between the convolute and the load, to shape the initial current pulse. We present the overall experimental configuration chosen for these experiments and initial results obtained over a set of experiments on an aluminum cylindrical liner. Current profiles measured at various critical locations across the system, are in good agreement with simulated current profiles. The liner inner free surface velocity measurements agree with the hydrocode results obtained using the measured load current as the input. The potential of the technique in terms of applications and achievable ramp pressure levels lies in the prospects for improving the DLCM efficiency.

South African Climates: Highlights From International Ocean Discovery Program Expedition 361

NASA Astrophysics Data System (ADS)

Hemming, S. R.; Hall, I. R.; LeVay, L.

2016-12-01

International Ocean Discovery Program Expedition 361 drilled six sites on the southeast African margin and in the Indian-Atlantic ocean gateway, southwest Indian Ocean, from 30 January to 31 March 2016. In total, 5175 m of core was recovered, with an average recovery of 102%, during 29.7 days of on-site operations. The sites, situated in the Mozambique Channel, at locations directly influenced by discharge from the Zambezi and Limpopo River catchments, the Natal Valley, the Agulhas Plateau, and the Cape Basin were targeted to reconstruct the history of the Greater Agulhas Current System over the past 5 Ma. The Agulhas Current transports 70 Sv of warm and saline surface waters from the tropical Indian Ocean along the East African margin to the tip of Africa. Exchanges of heat and moisture with the atmosphere influence southern African rainfall patterns. Recent ocean model and paleoceanographic data further point at a potential role of the Agulhas Current in controlling the strength and mode of the Atlantic Meridional Overturning Circulation (AMOC) during the Late Pleistocene. The main objectives of the expedition were to document the oceanographic properties of the Agulhas Current through tectonic and climatic changes during the Plio-Pleistocene, to determine the dynamics of the Indian-Atlantic gateway circulation during this time, to examine the connection of the Agulhas leakage and AMOC, to address the influence of the Agulhas Current on African terrestrial climates and potential links to Human evolution. Additionally, the Expedition set out to fulfill the needs of the Ancillary Project Letter, consisting of high-resolution interstitial water samples that will, and to constrain the temperature and salinity profiles of the ocean during the Last Glacial Maximum. Here we highlight some of the expedition successes and show how it has made major strides toward fulfilling each of these objectives. The recovered sequences allowed complete spliced stratigraphic sections to be generated that span the interval of 0 to between 0.2 and 7 Ma. These sediments provide an exceptional opportunity to generate decadal to millennial-scale climatic records that will resolve key paleoceanographic and paleoclimatic questions from a region poorly represented in the database of scientific drill sites.

Heating and current drive requirements towards steady state operation in ITER

NASA Astrophysics Data System (ADS)

Poli, Francesca; Kessel, Charles; Bonoli, Paul; Batchelor, Donald; Harvey, Bob

2013-10-01

Steady state scenarios envisaged for ITER aim at optimizing the bootstrap current, while maintaining sufficient confinement and stability. Non-inductive scenarios will need to operate with Internal Transport Barriers (ITBs) to reach adequate fusion gain at typical currents of 9 MA. Scenarios are established as relaxed flattop states with time-dependent transport simulations with TSC. The E × B flow shear from toroidal plasma rotation is expected to be low in ITER, with a major role in the ITB dynamics being played by magnetic geometry. Combinations of external sources that maintain weakly reversed shear profiles and ρ (qmin >= 0 . 5 are the focus of this work. Simulations indicate that, with a trade-off of the EC equatorial and upper launcher, the formation and sustainment of ITBs could be demonstrated with the baseline configuration. However, with proper constraints from peeling-ballooning theory on the pedestal width and height, the fusion gain and the maximum non-inductive current (6.2MA) are below the target. Upgrades of the heating and current drive system, like the use of Lower Hybrid current drive, could overcome these limitations. With 30MW of coupled LH in the flattop and operating at the Greenwald density, plasmas can sustain ~ 9 MA and achieve Q ~ 4 . Work supported by the US Department of Energy under DE-AC02-CH0911466.

Operation and development status of the J-PARC ion source

NASA Astrophysics Data System (ADS)

Yamazaki, S.; Ikegami, K.; Ohkoshi, K.; Ueno, A.; Koizumi, I.; Takagi, A.; Oguri, H.

2014-02-01

A cesium-free H- ion source driven with a LaB6 filament is being operated at the Japan Proton Accelerator Research Complex (J-PARC) without any serious trouble since the restoration from the March 2011 earthquake. The H- ion current from the ion source is routinely restricted approximately 19 mA for the lifetime of the filament. In order to increase the beam power at the linac beam operation (January to February 2013), the beam current from the ion source was increased to 22 mA. At this operation, the lifetime of the filament was estimated by the reduction in the filament current. According to the steep reduction in the filament current, the break of the filament was predicted. Although the filament has broken after approximately 10 h from the steep current reduction, the beam operation was restarted approximately 8 h later by the preparation for the exchange of new filament. At the study time for the 3 GeV rapid cycling synchrotron (April 2013), the ion source was operated at approximately 30 mA for 8 days. As a part of the beam current upgrade plan for the J-PARC, the front end test stand consisting of the ion source and the radio frequency quadrupole is under preparation. The RF-driven H- ion source developed for the J-PARC 2nd stage requirements will be tested at this test stand.

HIV infection Heightens Concurrent Risk of Functional Dependence in Persons With Chronic Methamphetamine Use

PubMed Central

Blackstone, K.; Iudicello, J. E.; Morgan, E. E.; Weber, E.; Moore, D. J.; Franklin, D. R.; Ellis, R. J.; Grant, I.; Woods, S. P.

2013-01-01

Objectives The causes of disability among chronic methamphetamine (MA) users are multifactorial. The current study examined the additive adverse impact of human immunodeficiency virus (HIV) infection, a common comorbidity in MA users, on functional dependence. Methods A large cohort of participants (N=798) stratified by lifetime MA dependence diagnoses (i.e., MA+ or MA−) and HIV serostatus (i.e., HIV+ or HIV−) underwent comprehensive baseline neuromedical, neuropsychiatric, and functional research evaluations, including assessment of neurocognitive symptoms in daily life, instrumental and basic activities of daily living, and employment status. Results Independent, additive effects of MA and HIV were observed across all measures of functional dependence, independent of other demographic, psychiatric, and substance use factors. The prevalence of global functional dependence increased in the expected stepwise fashion across the cohort, with the lowest rates in the MA−/HIV− group (29%) and the highest rates in the MA+/HIV+ sample (69%). The impact of HIV on MA-associated functional dependence was moderated by nadir CD4 count, such that MA use was associated with greater disability among those HIV-infected persons with higher, but not lower nadir CD4. Within the MA+/HIV+ cohort, functional dependence was reliably associated with neurocognitive impairment, lower cognitive reserve, polysubstance use, and major depressive disorder. Conclusions HIV infection confers an increased concurrent risk of MA-associated disability, particularly among HIV-infected persons without histories of immune compromise. Directed referrals, earlier HIV treatment, and compensatory strategies aimed at counteracting the effects of low cognitive reserve, neurocognitive impairment, and psychiatric comorbidities on functional dependence in MA+/HIV+ individuals may be warranted. PMID:23648641

Radiation dose calculations for CT scans with tube current modulation using the approach to equilibrium function

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

Li, Xinhua; Zhang, Da; Liu, Bob, E-mail: bliu7@mgh.harvard.edu

2014-11-01

Purpose: The approach to equilibrium function has been used previously to calculate the radiation dose to a shift-invariant medium undergoing CT scans with constant tube current [Li, Zhang, and Liu, Med. Phys. 39, 5347–5352 (2012)]. The authors have adapted this method to CT scans with tube current modulation (TCM). Methods: For a scan with variable tube current, the scan range was divided into multiple subscan ranges, each with a nearly constant tube current. Then the dose calculation algorithm presented previously was applied. For a clinical CT scan series that presented tube current per slice, the authors adopted an efficient approachmore » that computed the longitudinal dose distribution for one scan length equal to the slice thickness, which center was at z = 0. The cumulative dose at a specific point was a summation of the contributions from all slices and the overscan. Results: The dose calculations performed for a total of four constant and variable tube current distributions agreed with the published results of Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)]. For an abdomen/pelvis scan of an anthropomorphic phantom (model ATOM 701-B, CIRS, Inc., VA) on a GE Lightspeed Pro 16 scanner with 120 kV, N × T = 20 mm, pitch = 1.375, z axis current modulation (auto mA), and angular current modulation (smart mA), dose measurements were performed using two lines of optically stimulated luminescence dosimeters, one of which was placed near the phantom center and the other on the surface. Dose calculations were performed on the central and peripheral axes of a cylinder containing water, whose cross-sectional mass was about equal to that of the ATOM phantom in its abdominal region, and the results agreed with the measurements within 28.4%. Conclusions: The described method provides an effective approach that takes into account subject size, scan length, and constant or variable tube current to evaluate CT dose to a shift-invariant medium. For a clinical CT scan, dose calculations may be performed with a water-containing cylinder whose cross-sectional mass is equal to that of the subject. This method has the potential to substantially improve evaluations of patient dose from clinical CT scans, compared to CTDI{sub vol}, size-specific dose estimate (SSDE), or the dose evaluated for a TCM scan with a constant tube current equal to the average tube current of the TCM scan.« less

76 FR 23193 - Traffic Separation Schemes: In the Approaches to Portland, ME; Boston, MA; Narragansett Bay, RI...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-26

...-AB55 Traffic Separation Schemes: In the Approaches to Portland, ME; Boston, MA; Narragansett Bay, RI..., interim rule codifying traffic separation schemes in the approaches to Portland, ME; in the approaches to... Cape Fear River, NC, and updating the then-current regulations for the traffic separation scheme in the...

Craving Responses to Methamphetamine and Sexual Visual Cues in Individuals With Methamphetamine Use Disorder After Long-Term Drug Rehabilitation

PubMed Central

Huang, Shucai; Zhang, Zhixue; Dai, Yuanyuan; Zhang, Changcun; Yang, Cheng; Fan, Lidan; Liu, Jun; Hao, Wei; Chen, Hongxian

2018-01-01

Studies utilizing functional magnetic resonance imaging (fMRI) cue-reactivity paradigms have demonstrated that short-term abstinent or current methamphetamine (MA) users have increased brain activity in the ventral striatum, caudate nucleus and medial frontal cortex, when exposed to MA-related visual cues. However, patterns of brain activity following cue-reactivity in subjects with long-term MA abstinence, especially long-term compulsory drug rehabilitation, have not been well studied. To enrich knowledge in this field, functional brain imaging was conducted during a cue-reactivity paradigm task in 28 individuals with MA use disorder following long-term compulsory drug rehabilitation, and 27 healthy control subjects. The results showed that, when compared with controls, individuals with MA use disorder displayed elevated activity in the bilateral medial prefrontal cortex (mPFC) and right lateral posterior cingulate cortex in response to MA-related images. Additionally, the anterior cingulate region of mPFC activation during the MA-related cue-reactivity paradigm was positively correlated with craving alterations and previous frequency of drug use. No significant differences in brain activity in response to pornographic images were found between the two groups. Compared to MA cues, individuals with MA use disorder had increased activation in the occipital lobe when exposed to pornographic cues. In conclusion, the present study indicates that, even after long-term drug rehabilitation, individuals with MA use disorder have unique brain activity when exposed to MA-related cues. Additionally, our results illustrate that the libido brain response might be restored, and that sexual demand might be more robust than drug demand, in individuals with MA use disorder following long-term drug rehabilitation. PMID:29725310

Craving Responses to Methamphetamine and Sexual Visual Cues in Individuals With Methamphetamine Use Disorder After Long-Term Drug Rehabilitation.

PubMed

Huang, Shucai; Zhang, Zhixue; Dai, Yuanyuan; Zhang, Changcun; Yang, Cheng; Fan, Lidan; Liu, Jun; Hao, Wei; Chen, Hongxian

2018-01-01

Studies utilizing functional magnetic resonance imaging (fMRI) cue-reactivity paradigms have demonstrated that short-term abstinent or current methamphetamine (MA) users have increased brain activity in the ventral striatum, caudate nucleus and medial frontal cortex, when exposed to MA-related visual cues. However, patterns of brain activity following cue-reactivity in subjects with long-term MA abstinence, especially long-term compulsory drug rehabilitation, have not been well studied. To enrich knowledge in this field, functional brain imaging was conducted during a cue-reactivity paradigm task in 28 individuals with MA use disorder following long-term compulsory drug rehabilitation, and 27 healthy control subjects. The results showed that, when compared with controls, individuals with MA use disorder displayed elevated activity in the bilateral medial prefrontal cortex (mPFC) and right lateral posterior cingulate cortex in response to MA-related images. Additionally, the anterior cingulate region of mPFC activation during the MA-related cue-reactivity paradigm was positively correlated with craving alterations and previous frequency of drug use. No significant differences in brain activity in response to pornographic images were found between the two groups. Compared to MA cues, individuals with MA use disorder had increased activation in the occipital lobe when exposed to pornographic cues. In conclusion, the present study indicates that, even after long-term drug rehabilitation, individuals with MA use disorder have unique brain activity when exposed to MA-related cues. Additionally, our results illustrate that the libido brain response might be restored, and that sexual demand might be more robust than drug demand, in individuals with MA use disorder following long-term drug rehabilitation.

Studies of the System-Environment Interaction by Electron Beam Emission from a Sounding Rocket Payload in the Ionosphere

NASA Astrophysics Data System (ADS)

Myers, Neil Brubaker

The CHARGE-2 sounding rocket payload was designed to measure the transient and steady-state electrical charging of a space vehicle at low-Earth-orbit altitudes during the emission of a low-power electron beam from the vehicle. In addition to the electron gun, the payload contained several diagnostics to monitor plasma and waves resulting from the beam/space/vehicle interaction. The payload was separated into two sections, the larger section carried a 1-keV electron gun and was referred to as the mother vehicle. The smaller section, referred to as the daughter, was connected to the mother by an insulated, conducting tether and was deployed to a distance of up to 426 m across the geomagnetic field. Payload stabilization was obtained using thrusters that released cold nitrogen gas. In addition to performing electron beam experiments, the mother vehicle contained a high-voltage power supply capable of applying up to +450 V and 28 mA to the daughter through the tether. The 1-keV electron beam was generated at beam currents of 1 mA to 48 mA, measured at the exit aperture of the electron gun. Steady-state potentials of up to 560 V were measured for the mother vehicle. The daughter attained potentials of up to 1000 V relative to the background ionosphere and collected currents up to 6.5 mA. Thruster firings increased the current collection to the vehicle firing the thrusters and resulted in neutralization of the payload. The CHARGE-2 experiment was unique in that for the first time a comparison was made of the current collection between an electron beam-emitting vehicle and a non-emitting vehicle at high potential (400 V to 1000 V). The daughter current collection agreed well with the Parker-Murphy model, while the mother current collection always exceeded the Parker-Murphy limit and even exceeded the Langmuir-Blodgett predicted current below 240 km. The additional current collection of the mother is attributed to beam-plasma interaction. This additional source of collected current may be very important for successful electron beam emission at altitudes below 240 km.

Late Miocene to present-day exhumation and uplift of the Internal Zone of the Rif chain: Insights from low temperature thermochronometry and basin analysis

NASA Astrophysics Data System (ADS)

Romagny, A.; Ph. Münch; Cornée, J.-J.; Corsini, M.; Azdimousa, A.; Melinte-Dobrinescu, M. C.; Drinia, H.; Bonno, M.; Arnaud, N.; Monié, P.; Quillévéré, F.; Ben Moussa, A.

2014-07-01

Located on the margin of the west Alboran basin, the Gibraltar Arc (Betic-Rif mountain belt) displays post-Pliocene vertical movements evidenced by uplifted marine sedimentary basins and marine terraces. Quantification of vertical movements is an important clue to understand the origin of present-day relief generation in the Betic-Rif mountain chain together with the causes of the Messinian Salinity Crisis. In this paper, we present the results of a pluridisciplinary study combining an analysis of low temperature thermochronology and Pliocene basins evolution to constrain the exhumation history and surface uplift of internals units of the Rif belt (Northern Morocco). The mean (U-Th)/He apatite ages obtained from 11 samples are comprised between 14.1 and 17.8 Ma and display a wide dispersion, which could be explained by a great variability of apatite chemistries in the analyzed samples. No correlations between altitude and age have been found along altitudinal profile suggesting a rapid exhumation during this period. Thermal modeling using our (U-Th)/He apatite ages and geochronological data previously obtained in the same area (40Ar/39Ar and K/Ar data on biotite, zircon and apatite fission track) allow us to propose a cooling history. The rocks suffered a rapid cooling at 60-100 °C/Ma between 22.5 and 19 Ma, then cooled to temperatures around 40 °C between 19 and 18 Ma. They were re-heated at around 110 °C between 18 and 15 Ma then rapidly cooled and exhumed to reach the surface temperature at around 13 Ma. The re-heating could be related to a renewal in thrusting and burying of the inner zones. Between 15 and 13 Ma the cooling resumed at a rate of 50 °C/Ma indicating an exhumation rate of 0.8 mm/y considering an average 40 °C/km geothermal gradient. This exhumation may be linked to the extension in the Alboran Sea. Otherwise biostratigraphic and sedimentological analysis of Pliocene basins of the internal Rif provided informations on the more recent events and vertical movements. Pliocene deposits of the Rifian coast represent the passive infilling of palaeo-rias between 5.33 and 3.8 Ma. The whole coastal area was uplifted at slow average rates (0.01-0.03 mm/y) in relation with a northeastward tilting of 0.2-0.3° since the Lower-Pliocene. A late Pliocene to present extensional tectonics associated to uplift has been identified all along the coastal ranges of the Internal Zone of the Rif chain. This extension was coeval with the major late Pliocene to Pleistocene extensional episode of the Alboran Sea and appears to be still active nowadays. No significant late Messinian uplift was evidenced, thus calling into question the geodynamic models relating the closure of the marine gateways and the MSC to slab roll back.

Palaeopole for the 69 Ma Prospector Mountain stock: a critique of the Carmacks/`Baja BC' transport estimate for Yukon, Canada

NASA Astrophysics Data System (ADS)

Symons, D. T. A.; Kawasaki, K.; McCausland, P. J. A.; Hart, C. J. R.

2017-01-01

The 69 Ma Prospector Mountain stock is located in southwestern Yukon in the northern Canadian Cordillera. This massive monzonite-syenogranite stock is thought to be the intrusive volcanic centre for the surrounding coeval Carmacks Group volcanics. Anomalous palaeomagnetic data from these volcanics have provided the only evidence for the commonly posited hypothesis that the Yukon-Tanana terrane (YTT) was part of the far-travelled (1950 ± 600 km northward) `Baja BC' terrane from 70 to 50 Ma. All other geologic evidence and averaged palaeomagnetic data support a northward displacement of ˜415 ± 15 km. This study provides a direct test of the Carmacks volcanics' estimate and examines the possible causes of its anomalous results. Both the stock and volcanics are unmetamorphosed and rest unconformably on metamorphosed basement rocks of the YTT. Palaeomagnetic and mineral magnetic results from 17 of 19 tested sites (218 specimens) in the Prospector stock and its peripheral skarn isolated a stable thermoremanent magnetization (TRM) in magnetite or low-Ti titanomagnetite that was mostly determined on demagnetization between temperatures of 500 and 580 °C. The TRM has a direction of Decl. = 8.3°, Incl. = 82.4° (N = 17, k = 71.9, α95 = 4.2°), providing a non-significant northwards translation estimate of 70 ± 880 km for the YTT. The normal-polarity TRM direction at Prospector Mountain provides a highly significant palaeomagnetic reversals test with the reversed-polarity TRM of the 70 Ma Swede Dome stock, another volcanic centre of the Carmacks Group about 190 km to the north. The test affirms to a high probability that both stocks carry primary TRMs and have not been tectonically tilted significantly since emplacement. Combining the palaeopoles for these two stocks with that for the 75 Ma Mount Lorne volcanic centre stock about 210 km south of Prospector Mountain yields a combined northward translation estimate of 330 ± 400 km for the YTT since ˜71 Ma. This estimate agrees closely with the 415 ± 15 km estimate from geological constraints on strike-slip motion along the inboard Tintina fault zone since ˜70 Ma, and with the palaeomagnetic estimate of 650 ± 450 km northward since ˜108 Ma from four mid-Cretaceous batholiths. In contrast, the palaeomagnetic directions from four areas of the ˜70 Ma Carmacks volcanics are poorly clustered. Nonetheless their estimates of ˜1900 km northward have been used for a quarter of a century to support a far-travelled `Baja BC' tectonic model for the YTT. This paper discusses and concludes that the anomalous far-travelled estimates from the Carmacks volcanics are attributable to the unfortunate additive effects of inadequate averaging of secular variation, dipole offset error, unrecognized primary dip and other possible causes.

A sensitive assay using a native protein substrate for screening HIV-1 maturation inhibitors targeting the protease cleavage site between the matrix and capsid.

PubMed

Lee, Sook-Kyung; Cheng, Nancy; Hull-Ryde, Emily; Potempa, Marc; Schiffer, Celia A; Janzen, William; Swanstrom, Ronald

2013-07-23

The matrix/capsid processing site in the HIV-1 Gag precursor is likely the most sensitive target to inhibit HIV-1 replication. We have previously shown that modest incomplete processing at the site leads to a complete loss of virion infectivity. In the study presented here, a sensitive assay based on fluorescence polarization that can monitor cleavage at the MA/CA site in the context of the folded protein substrate is described. The substrate, an MA/CA fusion protein, was labeled with the fluorescein-based FlAsH (fluorescein arsenical hairpin) reagent that binds to a tetracysteine motif (CCGPCC) that was introduced within the N-terminal domain of CA. By limiting the size of CA and increasing the size of MA (with an N-terminal GST fusion), we were able to measure significant differences in polarization values as a function of HIV-1 protease cleavage. The sensitivity of the assay was tested in the presence of increasing amounts of an HIV-1 protease inhibitor, which resulted in a gradual decrease in the fluorescence polarization values demonstrating that the assay is sensitive in discerning changes in protease processing. The high-throughput screening assay validation in 384-well plates showed that the assay is reproducible and robust with an average Z' value of 0.79 and average coefficient of variation values of <3%. The robustness and reproducibility of the assay were further validated using the LOPAC(1280) compound library, demonstrating that the assay provides a sensitive high-throughput screening platform that can be used with large compound libraries for identifying novel maturation inhibitors targeting the MA/CA site of the HIV-1 Gag polyprotein.

Effects of Caps on Cost Sharing for Skilled Nursing Facility Services in Medicare Advantage Plans.

PubMed

Keohane, Laura M; Rahman, Momotazur; Thomas, Kali S; Trivedi, Amal N

2018-03-12

To evaluate a federal regulation effective in 2011 that limited how much that Medicare Advantage (MA) plans could charge for the first 20 days of care in a skilled nursing facility (SNF). Difference-in-differences retrospective analysis comparing SNF utilization trends from 2008-2012. Select MA plans. Members of 27 plans with mandatory cost sharing reductions (n=132,000) and members of 21 plans without such reductions (n=138,846). Mean monthly number of SNF admissions and days per 1,000 members; annual proportion of MA enrollees exiting the plan. In plans with mandated cost sharing reductions, cost sharing for the first 20 days of SNF care decreased from an average of $2,039 in 2010 to $992 in 2011. In adjusted analyses, plans with mandated cost-sharing reductions averaged 158.1 SNF days (95% confidence interval (CI)=153.2-163.1 days) per 1,000 members per month before the cost sharing cap. This measure increased by 14.3 days (95% CI=3.8-24.8 days, p=0.009) in the 2 years after cap implementation. However, increases in SNF utilization did not significantly differ between plans with and without mandated cost-sharing reductions (adjusted between-group difference: 7.1 days per 1,000 members, 95% CI=-6.5-20.8, p=.30). Disenrollment patterns did not change after the cap took effect. When a federal regulation designed to protect MA members from high out-of-pocket costs for postacute care took effect, the use of SNF services did not change. © 2018, Copyright the Authors Journal compilation © 2018, The American Geriatrics Society.

A meta-analysis of cortisol concentration, vocalization, and average daily gain associated with castration in beef cattle.

PubMed

Canozzi, Maria Eugênia Andrighetto; Mederos, America; Manteca, Xavier; Turner, Simon; McManus, Concepta; Zago, Daniele; Barcellos, Júlio Otávio Jardim

2017-10-01

A systematic review and meta-analysis (MA) were performed to summarize all scientific evidence for the effects of castration in male beef cattle on welfare indicators based on cortisol concentration, average daily gain (ADG), and vocalization. We searched five electronic databases, conference proceedings, and experts were contacted electronically. The main inclusion criteria involved completed studies using beef cattle up to one year of age undergoing surgical and non-surgical castration that presented cortisol concentration, ADG, or vocalization as an outcome. A random effect MA was conducted for each indicator separately with the mean of the control and treated groups. A total of 20 publications reporting 26 studies and 162 trials were included in the MA involving 1814 cattle. Between study heterogeneity was observed when analysing cortisol (I 2 =56.7%) and ADG (I 2 =79.6%). Surgical and non-surgical castration without drug administration compared to uncastrated animals showed no change (P≥0.05) in cortisol level. Multimodal therapy for pain did not decrease (P≥0.05) cortisol concentration after 30min when non-surgical castration was performed. Comparison between surgical castration, with and without anaesthesia, showed a tendency (P=0.077) to decrease cortisol levels after 120min of intervention. Non-surgical and surgical castration, performed with no pain mitigation, increased and tended to increase the ADG by 0.814g/d (P=0.001) and by 0.140g/d (P=0.091), respectively, when compared to a non-castrated group. Our MA study demonstrates an inconclusive result to draw recommendations on preferred castration practices to minimize pain in beef cattle. Copyright © 2017 Elsevier Ltd. All rights reserved.

Leaf Structural and Photosynthetic Characteristics, and Biomass Allocation to Foliage in Relation to Foliar Nitrogen Content and Tree Size in Three Betula Species

PubMed Central

NIINEMETS, ÜLO; PORTSMUTH, ANGELIKA; TRUUS, LAIMI

2002-01-01

Young trees 0·03–1·7 m high of three coexisting Betula species were investigated in four sites of varying soil fertility, but all in full daylight, to separate nutrient and plant size controls on leaf dry mass per unit area (MA), light‐saturated foliar photosynthetic electron transport rate (J) and the fraction of plant biomass in foliage (FL). Because the site effect was generally non‐significant in the analyses of variance with foliar nitrogen content per unit dry mass (NM) as a covariate, NM was used as an explaining variable of leaf structural and physiological characteristics. Average leaf area (S) and dry mass per leaf scaled positively with NM and total tree height (H) in all species. Leaf dry mass per unit area also increased with increasing H, but decreased with increasing NM, whereas the effects were species‐specific. Increases in plant size led to a lower and increases in NM to a greater FL and total plant foliar area per unit plant biomass (LAR). Thus, the self‐shading probably increased with increasing NM and decreased with increasing H. Nevertheless, the whole‐plant average MA, as well as MA values of topmost fully exposed leaves, correlated with NM and H in a similar manner, indicating that scaling of MA with NM and H did not necessarily result from the modified degree of within‐plant shading. The rate of photosynthetic electron transport per unit dry mass (JM) scaled positively with NM, but decreased with increasing H and MA. Thus, increases in MA with tree height and decreasing nitrogen content not only resulted in a lower plant foliar area (LAR = FL/MA), but also led to lower physiological activity of unit foliar biomass. The leaf parameters (JM, NM and MA) varied threefold, but the whole‐plant characteristic FL varied 20‐fold and LAR 30‐fold, indicating that the biomass allocation was more plastically adjusted to different plant internal nitrogen contents and to tree height than the foliar variables. Our results demonstrate that: (1) tree height and NM may independently control foliar structure and physiology, and have an even greater impact on biomass allocation; and (2) the modified within‐plant light availabilities alone do not explain the observed patterns. Although there were interspecific differences with respect to the statistical significance of the relationships, all species generally fit common regressions. However, these differences were consistent, and suggested that more competitive species with inherently larger growth rates also more plastically respond to N and H. PMID:12099350

What are the implications of rapid global warming for landslide-triggered turbidity current activity?

NASA Astrophysics Data System (ADS)

Clare, Michael; Peter, Talling; James, Hunt

2014-05-01

A geologically short-lived (~170kyr) episode of global warming occurred at ~55Ma, termed the Initial Eocene Thermal Maximum (IETM). Global temperatures rose by up to 8oC over only ~10kyr and a massive perturbation of the global carbon cycle occurred; creating a negative carbon isotopic (~-4% δ13C) excursion in sedimentary records. This interval has relevance to study of future climate change and its influence on geohazards including submarine landslides and turbidity currents. We analyse the recurrence frequency of turbidity currents, potentially initiated from large-volume slope failures. The study focuses on two sedimentary intervals that straddle the IETM and we discuss implications for turbidity current triggering. We present the results of statistical analyses (regression, generalised linear model, and proportional hazards model) for extensive turbidite records from an outcrop at Zumaia in NE Spain (N=285; 54.0 to 56.5 Ma) and based on ODP site 1068 on the Iberian Margin (N=1571; 48.2 to 67.6 Ma). The sedimentary sequences provide clear differentiation between hemipelagic and turbiditic mud with only negligible evidence of erosion. We infer dates for turbidites by converting hemipelagic bed thicknesses to time using interval-averaged accumulation rates. Multi-proxy dating techniques provide good age constraint. The background trend for the Zumaia record shows a near-exponential distribution of turbidite recurrence intervals, while the Iberian Margin shows a log-normal response. This is interpreted to be related to regional time-independence (exponential) and the effects of additive processes (log-normal). We discuss how a log-normal response may actually be generated over geological timescales from multiple shorter periods of random turbidite recurrence. The IETM interval shows a dramatic departure from both these background trends, however. This is marked by prolonged hiatuses (0.1 and 0.6 Myr duration) in turbidity current activity in contrast to the arithmetic mean recurrence, λ, for the full records (λ=0.007 and 0.0125 Myr). This period of inactivity is coincident with a dramatic carbon isotopic excursion (i.e. warmest part of the IETM) and heavily skews statistical analyses for both records. Dramatic global warming appears to exert a strong control on inhibiting turbidity current activity; whereas the effects of sea level change are not shown to be statistically significant. Rapid global warming is often implicated as a potential landslide trigger, due to dissociation of gas hydrates in response to elevated ocean temperatures. Other studies have suggested that intense global warming may actually be attributed to the atmospheric release of gas hydrates following catastrophic failure of large parts of a continental slope. Either way, a greater intensity of landslide and resultant turbidity current activity would be expected during the IETM; however, our findings are to the contrary. We offer some explanations in relation to potential triggers. Our work suggests that previous rapid global warming at the IETM did not trigger more frequent turbidity currents. This has direct relevance to future assessments relating to landslide-triggered tsunami hazard, and breakage of subsea cables by turbidity currents.

[Circadian rhythms and temperature homeostasis in monkeys during a flight on the Kosmos 1514 biosatellite

NASA Technical Reports Server (NTRS)

Klimovitskui, V. Ia; Alpatov, A. M.; Salzman, F. M.; Fuller, C. A.; Moore-Ede, M. S.

1987-01-01

In the course of a 5-day space flight of two rhesus-monkeys the following parameters were recorded at an interval of 16 min: core body temperature (Tc), skin temperature (Ts), and motor activity (MA). The telemetric Tc sensor was implanted subcutaneously in the right axilla, Ts thermistor was attached to the right ankle, and the MA piezotape was fixed to the inner side of the vest. Circadian rhythms of Tc varied with a period of 24 hours in one monkey and 25 hours in the other. The daily Tc decreased on the average by 0.5 degrees C, Ts fell immediately after launch and remained close to the lower limit throughout the flight. The Ts amplitude decreased 5-fold. Phases of the circadian rhythms of Ts changed and circadian rhythms of MA remained unchanged and equal to 24 hours.

[Circadian rhythms and temperature homeostasis in monkeys during a flight on the Kosmos 1514 biosatellite].

PubMed

Klimovitskuĭ, V Ia; Alpatov, A M; Salzman, F M; Fuller, C A; Moore-Ede, M S

1987-01-01

In the course of a 5-day space flight of two rhesus-monkeys the following parameters were recorded at an interval of 16 min: core body temperature (Tc), skin temperature (Ts), and motor activity (MA). The telemetric Tc sensor was implanted subcutaneously in the right axilla, Ts thermistor was attached to the right ankle, and the MA piezotape was fixed to the inner side of the vest. Circadian rhythms of Tc varied with a period of 24 hours in one monkey and 25 hours in the other. The daily Tc decreased on the average by 0.5 degrees C, Ts fell immediately after launch and remained close to the lower limit throughout the flight. The Ts amplitude decreased 5-fold. Phases of the circadian rhythms of Ts changed and circadian rhythms of MA remained unchanged and equal to 24 hours.

Variables influencing stimulus overselectivity and "tunnel vision" in developmentally delayed children.

PubMed

Rincover, A; Ducharme, J M

1987-01-01

Three variables (diagnosis, location of cues, and MA of learners) influencing stimulus control and stimulus overselectivity in autistic children were assessed. Eight autistic and 8 intellectually average children, matched on MA, were trained on two discrimination tasks; one task contained two "within-stimulus" (i.e., physically connected) cues; the other contained the same two cues presented "extra-stimulus" (i.e., physically separate). Generalization gradients were used following training to measure the degree of stimulus control acquired by each cue. Results showed: autistic subjects tended to respond overselectively only in the extra-stimulus condition; MA was positively correlated with breadth of learning; and when autistic children were overselective to one cue, some stimulus control was also acquired by the second cue. The notion of tunnel vision was discussed, as it may represent a "keystone" deficit interfering with stimulus control and learning by autistic children.

Reconstructing the evolution of a deep seated rockslide (Marzell) and its response to glacial retreat based on historic and remote sensing data

NASA Astrophysics Data System (ADS)

Fey, Christine; Wichmann, Volker; Zangerl, Christian

2017-12-01

In this study a combination of different topographic data from historic topographic maps and remote sensing is used to reconstruct and monitor the behaviour of the high alpine ice contact rockslide system Marzell and its response to glacial debuttressing in the Eastern Alps. Topographic data from archives (historical topographic maps, national glacier inventories, aerial images, orthoimages and ALS data) and data from monitoring campaigns (geodetic measurements, terrestrial laser scanning and UAV imaging campaigns) are processed to georeferenced images and/or elevation data, respectively. The data from different data sources is compiled and analysed with the aim to i) reconstruct the extent, thickness and volume changes of the glacier since 1893 and ii) to analyse the rockslide deformation evolution by extracting information about the displacement direction, dip angle, velocity and partial failure of rockslide slabs since 1951. The rockslide is compound of different rockslide slabs which move downwards as rigid blocks along basal shear zones. The analyses and interpretation of the data suggest a rotational type of rockslide failure mechanisms. The rockslide activity correlates with the ice volume loss at the adjacent part of the glacier. In the period between 1971 and 1997 the annual average rockslide activity was about 0.05 m/a and the annual average ice thickness loss was 0.1 m/a. Since the end of the last century the annual average ice thickness loss increased dramatically to 5 m/a. In that period the rockslide activity accelerated. The highest rockslide activity (up to 1.5 m/a) was observed in the 2000s when half of the slope toe was exposed because of glacier retreat. Since 2010 a deceleration of the rockslide can be observed. In the vicinity of the rockslide the glacier almost disappeared and lost 99.88% of its ice volume between 1893 and 2014. The geomorphological and geological information gathered about the rockslide evolution and the glacier retreat form the base for further rockslide analyses and allow to study and model the influence from glacial debuttressing.

Dark Currents and Their Effect on the Primary Beam in an X-band Linac

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

Bane, K.L.F.; Dolgashev, V.A.; Raubenheimer, T.

2005-05-27

We numerically study properties of primary dark currents in an X-band accelerating structure. For the H60VG3 structure considered for the Next Linear Collider (NLC) we first perform a fairly complete (with some approximations) calculation of dark current trajectories. These results are used to study properties of the dark current leaving the structure. For example, at accelerating gradient of 65 MV/m, considering two very different assumptions about dark current emission around the irises, we find that the fraction of emitted current leaving the structure to be a consistent {approx} 1%. Considering that {approx} 1 mA outgoing dark current is seen inmore » measurement, this implies that {approx} 100 mA (or 10 pC per period) is emitted within the structure itself. Using the formalism of the Lienard-Wiechert potentials, we then perform a systematic calculation of the transverse kick of dark currents on a primary linac bunch. The result is {approx} 1 V kick per mA (or per 0.1 pC per period) dark current emitted from an iris. For an entire structure we estimate the total kick on a primary bunch to be {approx} 15 V. For the NLC linac this translates to a ratio of (final) vertical beam offset to beam size of about 0.2. However, with the assumptions that needed to be made--particularly the number of emitters and their distribution within a structure--the accuracy of this result may be limited to the order of magnitude.« less

Polypyrrole-encapsulated vanadium pentoxide nanowires on a conductive substrate for electrode in aqueous rechargeable lithium battery.

PubMed

Liang, Chaowei; Fang, Dong; Cao, Yunhe; Li, Guangzhong; Luo, Zhiping; Zhou, Qunhua; Xiong, Chuanxi; Xu, Weilin

2015-02-01

Precursors of ammonium vanadium bronze (NH4V4O10) nanowires assembled on a conductive substrate were prepared by a hydrothermal method. After calcination at 360°C, the NH4V4O10 precursor transformed to vanadium pentoxide (V2O5) nanowires, which presented a high initial capacity of 135.0mA h g(-1) at a current density of 50mA g(-1) in 5M LiNO3 aqueous solution; while the specific capacity faded quickly over 50 cycles. By coating the surface of V2O5 nanowires with water-insoluble polypyrrole (PPy), the formed nanocomposite electrode exhibited a specific discharge capacity of 89.9mA h g(-1) at 50mA g(-1) (after 100 cycles). A V2O5@PPy //LiMn2O4 rechargeable lithium battery exhibited an initial discharge capacity of 95.2mA h g(-1); and after 100 cycles, a specific discharge capacity of 81.5mA h g(-1) could retain at 100mA g(-1). Copyright © 2014 Elsevier Inc. All rights reserved.

MaRIE theory, modeling and computation roadmap executive summary

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

Lookman, Turab

The confluence of MaRIE (Matter-Radiation Interactions in Extreme) and extreme (exascale) computing timelines offers a unique opportunity in co-designing the elements of materials discovery, with theory and high performance computing, itself co-designed by constrained optimization of hardware and software, and experiments. MaRIE's theory, modeling, and computation (TMC) roadmap efforts have paralleled 'MaRIE First Experiments' science activities in the areas of materials dynamics, irradiated materials and complex functional materials in extreme conditions. The documents that follow this executive summary describe in detail for each of these areas the current state of the art, the gaps that exist and the road mapmore » to MaRIE and beyond. Here we integrate the various elements to articulate an overarching theme related to the role and consequences of heterogeneities which manifest as competing states in a complex energy landscape. MaRIE experiments will locate, measure and follow the dynamical evolution of these heterogeneities. Our TMC vision spans the various pillar science and highlights the key theoretical and experimental challenges. We also present a theory, modeling and computation roadmap of the path to and beyond MaRIE in each of the science areas.« less

True Polar Wander and the Origin of the Hawaiian-Emperor Bend: New Evidence

NASA Astrophysics Data System (ADS)

Woodworth, D.; Gordon, R. G.; Seidman, L.; Zheng, L.

2017-12-01

We present an updated apparent polar wander (APW) path for the Pacific plate constructed from paleomagnetic poles determined from the skewness of marine magnetic anomalies, from equatorial sediment facies, and from paleocolatitudes of vertical cores of igneous rock. While paleocolatitude data provide some constraints, their usefulness is limited because they only limit the pole position in one direction, and the uncertainty in that direction is large because of the challenges of averaging secular variation. In contrast, secular variation contributes negligibly to the poles from skewness data, which give compact confidence limits for a well-defined interval of time. We review, update, or present six useful poles available for chrons 12r, 20r, 25r, 26r, 27r-31, and 32, corresponding respectively to 32 Ma, 44 Ma, 58 Ma, 60 Ma, 65 Ma, and 72 Ma. Moreover, we incorporate spin axis locations inferred from equatorial sediment facies [Suárez and Molnar; 1980; Gordon and Cape, 1981; Parés and Moore, 2005] and estimate their 95% confidence limits. An APW path for Pacific hotspots can be obtained by moving each Pacific plate paleomagnetic pole with the Pacific plate relative to the hotspots to a reconstruction that corresponds to the age of the pole. This path has a stillstand from 44 Ma to 12 Ma at a location (P1) about 3° from the present spin axis and a second stillstand from 81 Ma to 58 Ma at a location (P2) about 11° from the present spin axis. We hypothesize that the shift from P2 to P1 records an episode of true polar wander sometime between 58 and 44 Ma and that the shift from P1 to the present spin axis records another episode of true polar that has occurred since 12 Ma and may continue today. We test these hypotheses by comparing the APW path of Pacific hotspots with the APW path of Indo-Atlantic hotspots and find them in agreement. Our results imply that global hotspots have moved in unison with respect to the spin axis and that the Hawaiian-Emperor Bend (HEB) does not record a change in motion through the mantle of the Hawaiian plume. Instead the HEB records a change in Pacific plate motion over a stationary plume as originally proposed by W. J. Morgan.

Higher order mode couplers for normal conducting DORIS 5-cell cavities

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

Dewersteg, B.; Seesselberg, E.; Zolfaghari, A.

1985-10-01

The beam intensity of the DORIS e -e storage ring is limited to about 100 mA average circulation current as a result of instabilities driven by higher order rf cavity modes. Thus an investigation has been made of the higher order mode impedances of the DORIS rf accelerator cavities. These cavities are the same as the normally conducting inductively coupled 500 MHz 5-cell structures used in PETRA. The results of the investigation were applied for the construction of inductive and capacitive attenuation antennae corresponding to specific mode spectra and mode impedances. The antennae must fit into the existing 35 mmmore » pick up flanges of the cavities and in spite of these size and position limitations they must be efficient in reducing the shunt impedances of the dangerous modes.« less

Design Concept for a Compact ERL to Drive a VUV/Soft X-Ray FEL

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

Christopher Tennant ,David Douglas

2011-03-01

We explore possible upgrades of the existing Jefferson Laboratory IR/UV FEL driver to higher electron beam energy and shorter wavelength through use of multipass recirculation to drive an amplifier FEL. The system would require beam energy at the wiggler of 600 MeV with 1 mA of average current. The system must generate a high brightness beam, configure it appropriately, and preserve beam quality through the acceleration cycle ? including multiple recirculations ? and appropriately manage the phase space during energy recovery. The paper will discuss preliminary design analysis of the longitudinal match, space charge effects in the linac, and recirculatormore » design issues, including the potential for the microbunching instability. A design concept for the low energy recirculator and an emittance preserving lattice solution will be presented.« less

New compact hohlraum configuration research at the 1.7 MA Z-pinch generator

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

Kantsyrev, V. L., E-mail: victor@unr.edu; Shrestha, I. K.; Esaulov, A. A.

A new compact Z-pinch x-ray hohlraum design with parallel-driven x-ray sources was experimentally demonstrated in a full configuration with a central target and tailored shine shields (to provide a symmetric temperature distribution on the target) at the 1.7 MA Zebra generator. This presentation reports on the joint success of two independent lines of research. One of these was the development of new sources – planar wire arrays (PWAs). PWAs turned out to be a prolific radiator. Another success was the drastic improvement in energy efficiency of pulsed-power systems, such as the Load Current Multiplier (LCM). The Zebra/LCM generator almost doubledmore » the plasma load current to 1.7 MA. The two above-mentioned innovative approaches were used in combination to produce a new compact hohlraum design for ICF, as jointly proposed by SNL and UNR. Good agreement between simulated and measured radiation temperature of the central target is shown. Experimental comparison of PWAs with planar foil liners (PFL) - another viable alternative to wire array loads at multi-MA generators show promising data. Results of research at the University of Nevada Reno allowed for the study of hohlraum coupling physics at University-scale generators. The advantages of new hohlraum design applications for multi-MA facilities with W or Au double PWAs or PFL x-ray sources are discussed.« less

Saddle antenna radio frequency ion sources

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

Dudnikov, V., E-mail: vadim@muonsinc.com; Johnson, R.; Murray, S.

Existing RF ion sources for accelerators have specific efficiencies for H{sup +} and H{sup −} ion generation ∼3–5 mA/cm{sup 2} kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) surface plasma source (SPS) described here was developed to improve H{sup −} ion production efficiency, reliability, and availability. In SA RF ion source, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm{sup 2} kW. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA withmore » RF power ∼1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ∼4 kW RF. Continuous wave (CW) operation of the SA SPS has been tested on the test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. CW operation with negative ion extraction was tested with RF power up to ∼1.2 kW in the plasma with production up to Ic = 7 mA. A stable long time generation of H{sup −} beam without degradation was demonstrated in RF discharge with AlN discharge chamber.« less

Comparison of thermal modeling, microstructural analysis, and Ti-in-quartz thermobarometry to constrain the thermal history of a cooling pluton during deformation in the Mount Abbot Quadrangle, CA

NASA Astrophysics Data System (ADS)

Nevitt, Johanna M.; Warren, Jessica M.; Kidder, Steven; Pollard, David D.

2017-03-01

Granitic plutons commonly preserve evidence for jointing, faulting, and ductile fabric development during cooling. Constraining the spatial variation and temporal evolution of temperature during this deformation could facilitate an integrated analysis of heterogeneous deformation over multiple length-scales through time. Here, we constrain the evolving temperature of the Lake Edison granodiorite within the Mount Abbot Quadrangle (central Sierra Nevada, CA) during late Cretaceous deformation by combining microstructural analysis, titanium-in-quartz thermobarometry (TitaniQ), and thermal modeling. Microstructural and TitaniQ analyses were applied to 12 samples collected throughout the pluton, representative of either the penetrative "regional" fabric or the locally strong "fault-related" fabric. Overprinting textures and mineral assemblages indicate the temperature decreased from 400-500°C to <350°C during faulting. TitaniQ reveals consistently lower Ti concentrations for partially reset fault-related fabrics (average: 12 ± 4 ppm) than for regional fabrics (average: 31 ± 12 ppm), suggesting fault-related fabrics developed later, following a period of pluton cooling. Uncertainties, particularly in TiO2 activity, significantly limit further quantitative thermal estimates using TitaniQ. In addition, we present a 1-D heat conduction model that suggests average pluton temperature decreased from 585°C at 85 Ma to 332°C at 79 Ma, consistent with radiometric age data for the field. Integrated with the model results, microstructural temperature constraints suggest faulting initiated by ˜83 Ma, when the temperature was nearly uniform across the pluton. Thus, spatially heterogeneous deformation cannot be attributed to a persistent temperature gradient, but may be related to regional structures that develop in cooling plutons.

Early Neogene foreland of the Zagros, implications for the initial closure of the Neo-Tethys and kinematics of crustal shortening

NASA Astrophysics Data System (ADS)

Pirouz, Mortaza; Avouac, Jean-Philippe; Hassanzadeh, Jamshid; Kirschvink, Joseph L.; Bahroudi, Abbas

2017-11-01

We study the transition from passive margin to foreland basin sedimentation now exposed in the High Zagros belt to provide chronological constraints on the initial stage of Arabia-Eurasia collision and closure of the Neo-Tethys. We performed magnetostratigraphy and strontium isotope stratigraphy along two sections near the Zagros suture which expose the oldest preserved foreland deposits: the Shalamzar section in the west and the Dehmoord section in the east. The top of the passive margin Asmari formation has an age of 28-29 Ma in the High Zagros and is overlain by foreland deposits with a major basal unconformity representing 7 Myr of hiatus. The base of the foreland deposits has an age of 21.5 Ma at Dehmoord and ca. 26 Ma at Shalamzar. The sedimentation rate increased from 30 m/Myr in the passive margin to 247 m/Myr in the foreland. Combined with available age constraints across the Zagros, our results show that the unconformity is diachronous and records the southwestward migration of the flexural bulge within the Arabian plate at an average rate of 24 ± 2 mm/yr over the last 27 Ma. The time evolution of sediment accumulation in the Zagros foreland follows the prediction from a flexural model, as the foreland is thrust beneath the orogenic wedge and loaded by the wedge and basin fill. We detect the onset of forebulge formation within the Asmari Formation around 25 Ma. We conclude that closure of the Neo-Tethys formed the Zagros collisional wedge at 27 ± 2 Ma. Hence, the Arabia-Eurasia collision was probably not the main driver of global cooling which started near the Eocene-Oligocene boundary (ca. 33.7 Ma). We estimate 650 km of forebulge migration since the onset of the collision which consists of 350 km of shortening across the orogen, and 300 km of widening of the wedge and increasing flexural rigidity of Arabia. We conclude the average rate of shortening across the Zagros to be ca. 13 mm/yr over the last 27 Myr; a value comparable to the modern rate. Palinspastic restoration of structural cross-sections and crustal volume conservation comprise only ca. 200 km of shortening across the Zagros and metamorphic Sanandaj-Sirjan belt implying that at least 150 km of the Arabian crust was underthrust beneath Eurasia without contributing to crustal thickening, possibly due to eclogitization.

Na-Zn liquid metal battery

NASA Astrophysics Data System (ADS)

Xu, Junli; Kjos, Ole Sigmund; Osen, Karen Sende; Martinez, Ana Maria; Kongstein, Ole Edvard; Haarberg, Geir Martin

2016-11-01

A new kind of membrane free liquid metal battery was developed. The battery employs liquid sodium and zinc as electrodes both in liquid state, and NaCl-CaCl2 molten salts as electrolyte. The discharge flat voltage is in the range of about 1.4 V-1.8 V, and the cycle efficiency achieved is about 90% at low discharge current densities (below 40 mA cm-2). Moreover, this battery can also be charged and discharged at high current density with good performance. The discharge flat voltage is above 1.1 V when it is discharged at 100 mA cm-2, while it is about 0.8 V with 100% cycle efficiency when it is discharged at 200 mA cm-2. Compared to other reported liquid metal battery, this battery has lower cost, which suggests broad application prospect in energy storage systems for power grid.

Effect of Hydrogen Charging on the Stress Corrosion Behavior of 2205 Duplex Stainless Steel Under 3.5 wt.% NaCl Thin Electrolyte Layer

NASA Astrophysics Data System (ADS)

Zhao, Tianliang; Liu, Zhiyong; Hu, Shanshan; Du, Cuiwei; Li, Xiaogang

2017-05-01

The effect of hydrogen charging on the stress corrosion cracking (SCC) behavior of 2205 duplex stainless steel (DSS) under 3.5 wt.% NaCl thin electrolyte layer was investigated on precharged samples through hydrogen determination, electrochemical measurement, and slow strain rate tensile test. Results show that hydrogen charging weakens the passive film without inducing any obvious trace of localized anodic dissolution. Therefore, hydrogen charging increases the SCC susceptibility of 2205 DSS mainly through mechanism of hydrogen embrittlement rather than mechanism of localized anodic dissolution. 2205 DSS shows a more susceptibility to hydrogen under the TEL when hydrogen charging current density (HCCD) is between 20 and 50 mA cm-2. The increasing trend is remarkable when hydrogen charging current density increases from 20 to 50 mA cm-2 and fades after 50 mA cm-2.

The continued development of the Spallation Neutron Source external antenna H- ion sourcea)

NASA Astrophysics Data System (ADS)

Welton, R. F.; Carmichael, J.; Desai, N. J.; Fuga, R.; Goulding, R. H.; Han, B.; Kang, Y.; Lee, S. W.; Murray, S. N.; Pennisi, T.; Potter, K. G.; Santana, M.; Stockli, M. P.

2010-02-01

The U.S. Spallation Neutron Source (SNS) is an accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to ensure that the SNS will meet its operational commitments as well as provide for future facility upgrades with high reliability, we are developing a rf-driven, H- ion source based on a water-cooled, ceramic aluminum nitride (AlN) plasma chamber. To date, early versions of this source have delivered up to 42 mA to the SNS front end and unanalyzed beam currents up to ˜100 mA (60 Hz, 1 ms) to the ion source test stand. This source was operated on the SNS accelerator from February to April 2009 and produced ˜35 mA (beam current required by the ramp up plan) with availability of ˜97%. During this run several ion source failures identified reliability issues, which must be addressed before the source re-enters production: plasma ignition, antenna lifetime, magnet cooling, and cooling jacket integrity. This report discusses these issues, details proposed engineering solutions, and notes progress to date.

Design of a New Acceleration System for High-Current Pulsed Proton Beams from an ECR Source

NASA Astrophysics Data System (ADS)

Cooper, Andrew L.; Pogrebnyak, Ivan; Surbrook, Jason T.; Kelly, Keegan J.; Carlin, Bret P.; Champagne, Arthur E.; Clegg, Thomas B.

2014-03-01

A primary objective for accelerators at TUNL's Laboratory for Experimental Nuclear Astrophysics (LENA) is to maximize target beam intensity to ensure a high rate of nuclear events during each experiment. Average proton target currents of several mA are needed from LENA's electron cyclotron resonance (ECR) ion source because nuclear cross sections decrease substantially at energies of interest <200 keV. We seek to suppress undesired continuous environmental background by pulsing the beam and detecting events only during beam pulses. To improve beam intensity and transport, we installed a more powerful, stable microwave system for the ECR plasma, and will install a new acceleration system. This system will: reduce defocusing effects of the beam's internal space charge; provide better vacuum with a high gas conductance accelerating column; suppress bremsstrahlung X-rays produced when backstreaming electrons strike internal acceleration tube structures; and provide better heat dissipation by using deionized water to provide the current drain needed to establish the accelerating tube's voltage gradient. Details of beam optical modeling calculations, proposed accelerating tube design, and initial beam pulsing tests will be described. Work supported in part by USDOE Office of HE and Nuclear Physics.

New progress of high current gasdynamic ion source (invited)

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

Skalyga, V., E-mail: skalyga@ipfran.ru; Sidorov, A.; Vodopyanov, A.

2016-02-15

The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)—the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller’s ECRIS confinement, i.e., the quasi-gasdynamic one similar to that in fusion mirror traps. Experimental studies of gasdynamic ECRIS were performed at Simple Mirror Ion Source (SMIS) 37 facility. The plasma was created by 37.5 and 75 GHz gyrotron radiation with power up to 100 kW. High frequency microwaves allowed to create and sustain plasma withmore » significant density (up to 8 × 10{sup 13} cm{sup −3}) and to maintain the main advantages of conventional ECRIS such as high ionization degree and low ion energy. Reaching such high plasma density relies on the fact that the critical density grows with the microwave frequency squared. High microwave power provided the average electron energy on a level of 50-300 eV enough for efficient ionization even at neutral gas pressure range of 10{sup −4}–10{sup −3} mbar. Gasdynamic ECRIS has demonstrated a good performance producing high current (100-300 mA) multi-charged ion beams with moderate average charge (Z = 4-5 for argon). Gasdynamic ECRIS has appeared to be especially effective in low emittance hydrogen and deuterium beams formation. Proton beams with current up to 500 emA and RMS emittance below 0.07 π ⋅ mm ⋅ mrad have been demonstrated in recent experiments.« less

Electrospun single crystalline fork-like K2V8O21 as high-performance cathode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Hao, Pengfei; Zhu, Ting; Su, Qiong; Lin, Jiande; Cui, Rong; Cao, Xinxin; Wang, Yaping; Pan, Anqiang

2018-06-01

Single crystalline fork-like potassium vanadate (K2V8O21) has been successfully prepared through electrospinning combined with a subsequent annealing process. The as-obtained K2V8O21 forks show a unique layer-by-layer stacked structure with conductive carbon. When used as cathode materials for lithium-ion batteries, the as-prepared fork-like materials exhibit high specific discharge capacity and excellent cyclic stability. High specific discharge capacity of 200.2 mA h g-1 and 131.5 mA h g-1 can be delivered at the current densities of 50 mA g-1 and 500 mA g-1, respectively. Furthermore, the K2V8O21 electrodes exhibit excellent long-term cycling stability that maintain a capacity of 108.3 mA h g-1 after 300 cycles at 500 mA g-1 with a fading rate of only 0.054% per cycle, revealing their potential applications in next generation high-performance lithium-ion batteries.

Analysis of Commute Times and Neurobehavioral Performance Capacity in Aviation Cabin Crew

DTIC Science & Technology

2012-09-01

sea on the alertness of ma- rine pilots working extended hours. Chronobiology International, 25(2), 399-411. Gallup, Inc. (2007). Workers average...Dawson, D., & Roach, G.D. (2006). Do short international layovers al- low sufficient opportunity for pilots to recover? Chronobiology

Stratified Microbial Structure and Activity in Sulfide- and Methane-Producing Anaerobic Sewer Biofilms

PubMed Central

Sun, Jing; Hu, Shihu; Sharma, Keshab Raj; Ni, Bing-Jie

2014-01-01

Simultaneous production of sulfide and methane by anaerobic sewer biofilms has recently been observed, suggesting that sulfate-reducing bacteria (SRB) and methanogenic archaea (MA), microorganisms known to compete for the same substrates, can coexist in this environment. This study investigated the community structures and activities of SRB and MA in anaerobic sewer biofilms (average thickness of 800 μm) using a combination of microelectrode measurements, molecular techniques, and mathematical modeling. It was seen that sulfide was mainly produced in the outer layer of the biofilm, between the depths of 0 and 300 μm, which is in good agreement with the distribution of SRB population as revealed by cryosection-fluorescence in situ hybridization (FISH). SRB had a higher relative abundance of 20% on the surface layer, which decreased gradually to below 3% at a depth of 400 μm. In contrast, MA mainly inhabited the inner layer of the biofilm. Their relative abundances increased from 10% to 75% at depths of 200 μm and 700 μm, respectively, from the biofilm surface layer. High-throughput pyrosequencing of 16S rRNA amplicons showed that SRB in the biofilm were mainly affiliated with five genera, Desulfobulbus, Desulfomicrobium, Desulfovibrio, Desulfatiferula, and Desulforegula, while about 90% of the MA population belonged to the genus Methanosaeta. The spatial organizations of SRB and MA revealed by pyrosequencing were consistent with the FISH results. A biofilm model was constructed to simulate the SRB and MA distributions in the anaerobic sewer biofilm. The good fit between model predictions and the experimental data indicate that the coexistence and spatial structure of SRB and MA in the biofilm resulted from the microbial types and their metabolic transformations and interactions with substrates. PMID:25192994

40Ar/ 39Ar ages and paleomagnetism of São Miguel lavas, Azores

NASA Astrophysics Data System (ADS)

Johnson, Catherine L.; Wijbrans, Jan R.; Constable, Catherine G.; Gee, Jeff; Staudigel, Hubert; Tauxe, Lisa; Forjaz, Victor-H.; Salgueiro, Mário

1998-08-01

We present new 40Ar/ 39Ar ages and paleomagnetic data for São Miguel island, Azores. Paleomagnetic samples were obtained for 34 flows and one dike; successful mean paleomagnetic directions were obtained for 28 of these 35 sites. 40Ar/ 39Ar age determinations on 12 flows from the Nordeste complex were attempted successfully: ages obtained are between 0.78 Ma and 0.88 Ma, in contrast to published K-Ar ages of 1 Ma to 4 Ma. Our radiometric ages are consistent with the reverse polarity paleomagnetic field directions, and indicate that the entire exposed part of the Nordeste complex is of a late Matuyama age. The duration of volcanism across São Miguel is significantly less than previously believed, which has important implications for regional melt generation processes, and temporal sampling of the geomagnetic field. Observed stable isotope and trace element trends across the island can be explained, at least in part, by communication between different magma source regions at depth. The 40Ar/ 39Ar ages indicate that our normal polarity paleomagnetic data sample at least 0.1 Myr (0-0.1 Ma) and up to 0.78 Myr (0-0.78 Ma) of paleosecular variation and our reverse polarity data sample approximately 0.1 Myr (0.78-0.88 Ma) of paleosecular variation. Our results demonstrate that precise radiometric dating of numerous flows sampled is essential to accurate inferences of long-term geomagnetic field behavior. Negative inclination anomalies are observed for both the normal and reverse polarity time-averaged field. Within the data uncertainties, normal and reverse polarity field directions are antipodal, but the reverse polarity field shows a significant deviation from a geocentric axial dipole direction.

THE DATA REDUCTION PIPELINE FOR THE SDSS-IV MaNGA IFU GALAXY SURVEY

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

Law, David R.; Cherinka, Brian; Yan, Renbin

2016-10-01

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622–10354 Å and an average footprint of ∼500 arcsec{sup 2} per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ∼100 million raw-frame spectra and ∼10 millionmore » reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline algorithms and centralized metadata framework that produce sky-subtracted spectrophotometrically calibrated spectra and rectified three-dimensional data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13, we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ∼8500 Å and reach a typical 10 σ limiting continuum surface brightness μ  = 23.5 AB arcsec{sup −2} in a five-arcsecond-diameter aperture in the g -band. The wavelength calibration of the MaNGA data is accurate to 5 km s{sup −1} rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of σ  = 72 km s{sup −1}.« less

Using U-Th-Pb petrochronology to determine rates of ductile thrusting: Time windows into the Main Central Thrust, Sikkim Himalaya

NASA Astrophysics Data System (ADS)

Mottram, Catherine M.; Parrish, Randall R.; Regis, Daniele; Warren, Clare J.; Argles, Tom W.; Harris, Nigel B. W.; Roberts, Nick M. W.

2015-07-01

Quantitative constraints on the rates of tectonic processes underpin our understanding of the mechanisms that form mountains. In the Sikkim Himalaya, late structural doming has revealed time-transgressive evidence of metamorphism and thrusting that permit calculation of the minimum rate of movement on a major ductile fault zone, the Main Central Thrust (MCT), by a novel methodology. U-Th-Pb monazite ages, compositions, and metamorphic pressure-temperature determinations from rocks directly beneath the MCT reveal that samples from 50 km along the transport direction of the thrust experienced similar prograde, peak, and retrograde metamorphic conditions at different times. In the southern, frontal edge of the thrust zone, the rocks were buried to conditions of 550°C and 0.8 GPa between 21 and 18 Ma along the prograde path. Peak metamorphic conditions of 650°C and 0.8-1.0 GPa were subsequently reached as this footwall material was underplated to the hanging wall at 17-14 Ma. This same process occurred at analogous metamorphic conditions between 18-16 Ma and 14.5-13 Ma in the midsection of the thrust zone and between 13 Ma and 12 Ma in the northern, rear edge of the thrust zone. Northward younging muscovite 40Ar/39Ar ages are consistently 4 Ma younger than the youngest monazite ages for equivalent samples. By combining the geochronological data with the >50 km minimum distance separating samples along the transport axis, a minimum average thrusting rate of 10 ± 3 mm yr-1 can be calculated. This provides a minimum constraint on the amount of Miocene India-Asia convergence that was accommodated along the MCT.

The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey

NASA Astrophysics Data System (ADS)

Law, David R.; Cherinka, Brian; Yan, Renbin; Andrews, Brett H.; Bershady, Matthew A.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Bolton, Adam S.; Brownstein, Joel R.; Bundy, Kevin; Chen, Yanmei; Drory, Niv; D'Souza, Richard; Fu, Hai; Jones, Amy; Kauffmann, Guinevere; MacDonald, Nicholas; Masters, Karen L.; Newman, Jeffrey A.; Parejko, John K.; Sánchez-Gallego, José R.; Sánchez, Sebastian F.; Schlegel, David J.; Thomas, Daniel; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.; Zhang, Kai

2016-10-01

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622-10354 Å and an average footprint of ˜500 arcsec2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ˜100 million raw-frame spectra and ˜10 million reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline algorithms and centralized metadata framework that produce sky-subtracted spectrophotometrically calibrated spectra and rectified three-dimensional data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13, we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ˜8500 Å and reach a typical 10σ limiting continuum surface brightness μ = 23.5 AB arcsec-2 in a five-arcsecond-diameter aperture in the g-band. The wavelength calibration of the MaNGA data is accurate to 5 km s-1 rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of σ = 72 km s-1.

Stratified microbial structure and activity in sulfide- and methane-producing anaerobic sewer biofilms.

PubMed

Sun, Jing; Hu, Shihu; Sharma, Keshab Raj; Ni, Bing-Jie; Yuan, Zhiguo

2014-11-01

Simultaneous production of sulfide and methane by anaerobic sewer biofilms has recently been observed, suggesting that sulfate-reducing bacteria (SRB) and methanogenic archaea (MA), microorganisms known to compete for the same substrates, can coexist in this environment. This study investigated the community structures and activities of SRB and MA in anaerobic sewer biofilms (average thickness of 800 μm) using a combination of microelectrode measurements, molecular techniques, and mathematical modeling. It was seen that sulfide was mainly produced in the outer layer of the biofilm, between the depths of 0 and 300 μm, which is in good agreement with the distribution of SRB population as revealed by cryosection-fluorescence in situ hybridization (FISH). SRB had a higher relative abundance of 20% on the surface layer, which decreased gradually to below 3% at a depth of 400 μm. In contrast, MA mainly inhabited the inner layer of the biofilm. Their relative abundances increased from 10% to 75% at depths of 200 μm and 700 μm, respectively, from the biofilm surface layer. High-throughput pyrosequencing of 16S rRNA amplicons showed that SRB in the biofilm were mainly affiliated with five genera, Desulfobulbus, Desulfomicrobium, Desulfovibrio, Desulfatiferula, and Desulforegula, while about 90% of the MA population belonged to the genus Methanosaeta. The spatial organizations of SRB and MA revealed by pyrosequencing were consistent with the FISH results. A biofilm model was constructed to simulate the SRB and MA distributions in the anaerobic sewer biofilm. The good fit between model predictions and the experimental data indicate that the coexistence and spatial structure of SRB and MA in the biofilm resulted from the microbial types and their metabolic transformations and interactions with substrates. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

SU-E-I-22: A Comprehensive Investigation of Noise Variations Between the GE Discovery CT750 HD and GE LightSpeed VCT

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

Bache, S; Loyer, E; Stauduhar, P

2015-06-15

Purpose: To quantify and compare the noise properties between two GE CT models-the Discovery CT750 HD (aka HD750) and LightSpeed VCT, with the overall goal of assessing the impact in clinical diagnostic practice. Methods: Daily QC data from a fleet of 9 CT scanners currently in clinical use were investigated – 5 HD750 and 4 VCT (over 600 total acquisitions for each scanner). A standard GE QC phantom was scanned daily using two sets of scan parameters with each scanner over 1 year. Water CT number and standard deviation were recorded from the image of water section of the QCmore » phantom. The standard GE QC scan parameters (Pitch = 0.516, 120kVp, 0.4s, 335mA, Small Body SFOV, 5mm thickness) and an in-house developed protocol (Axial, 120kVp, 1.0s, 240mA, Head SFOV, 5mm thickness) were used, with Standard reconstruction algorithm. Noise was measured as the standard deviation in the center of the water phantom image. Inter-model noise distributions and tube output in mR/mAs were compared to assess any relative differences in noise properties. Results: With the in-house protocols, average noise for the five HD750 scanners was ∼9% higher than the VCT scanners (5.8 vs 5.3). For the GE QC protocol, average noise with the HD750 scanners was ∼11% higher than with the VCT scanners (4.8 vs 4.3). This discrepancy in noise between the two models was found despite the tube output in mR/mAs being comparable with the HD750 scanners only having ∼4% lower output (8.0 vs 8.3 mR/mAs). Conclusion: Using identical scan protocols, average noise in images from the HD750 group was higher than that from the VCT group. This confirms feedback from an institutional radiologist’s feedback regarding grainier patient images from HD750 scanners. Further investigation is warranted to assess the noise texture and distribution, as well as clinical impact.« less

Photodynamic therapy of diseased bone

NASA Astrophysics Data System (ADS)

Bisland, Stuart K.; Yee, Albert; Siewerdsen, Jeffery; Wilson, Brian C.; Burch, Shane

2005-08-01

Objective: Photodynamic therapy (PDT) defines the oxygen-dependent reaction that occurs upon light-mediated activation of a photosensitizing compound, culminating in the generation of cytotoxic, reactive oxygen species, predominantly, singlet oxygen. We are investigating PDT treatment of diseased bone. Methods: Using a rat model of human breast cancer (MT-1)-derived bone metastasis we confirmed the efficacy of benzoporphyrin-derivative monoacid (BPD-MA)-PDT for treating metastatic lesions within vertebrae or long bones. Results: Light administration (150 J) 15 mins after BPDMA (2.5 mg/Kg, i.v.) into the lumbar (L3) vertebra of rats resulted in complete ablation of the tumour and surrounding bone marrow 48 hrs post-PDT without paralysis. Porcine vertebrae provided a model comparable to that of human for light propagation (at 150 J/cm) and PDT response (BPD-MA; 6 mg/m2, i.v.) in non-tumour vertebrae. Precise fibre placement was afforded by 3-D cone beam computed tomography. Average penetration depth of light was 0.16 +/- 0.04 cm, however, the necrotic/non-necrotic interface extended 0.6 cm out from the treatment fiber with an average incident fluence rate of 4.3 mW/cm2. Non-necrotic tissue damage was evident 2 cm out from the treatment fiber. Current studies involving BPD-MA-PDT treatment of primary osteosarcomas in the forelimbs of dogs are very promising. Magnetic resonance imaging 24 hr post treatment reveal well circumscribed margins of treatment that encompass the entire 3-4 cm lesion. Finally, we are also interested in using 5-aminolevulinic acid (ALA) mediated PDT to treat osteomyelitis. Response to therapy was monitored as changes in bioluminescence signal of staphylococcus aureus (SA)-derived biofilms grown onto 0.5 cm lengths of wire and subjected to ALA-PDT either in vitro or in vivo upon implant into the intramedullary space of rat tibia. Transcutaneous delivery of PDT (75 J/cm2) effectively eradicated SAbiofilms within bone. Conclusions: Results support the application of PDT to the treatment of primary or metastatic lesions within bone. Secondly, that ALA-PDT may be useful as a treatment for osteomyelitis. Further studies aim to optimize the parameters of delivering PDT into bone and explore imaging technologies that can be used for clinical PDT.

High efficiency single transverse mode photonic band crystal lasers with low vertical divergence

NASA Astrophysics Data System (ADS)

Zhao, Shaoyu; Qu, Hongwei; Liu, Yun; Li, Lunhua; Chen, Yang; Zhou, Xuyan; Lin, Yuzhe; Liu, Anjin; Qi, Aiyi; Zheng, Wanhua

2016-10-01

High efficiency 980 nm longitudinal photonic band crystal (PBC) edge emitting laser diodes are designed and fabricated. The calculated results show that eight periods of Al0.1Ga0.9As and Al0.25Ga0.75As layer pairs can reduce the vertical far field divergence to 10.6° full width at half maximum (FWHM). The broad area (BA) lasers show a very high internal quantum efficiency ηi of 98% and low internal loss αi of 1.92 cm-1. Ridge waveguide (RW) lasers with 3 mm cavity length and 5um strip width provide 430 mW stable single transverse mode output at 500 mA injection current with power conversion efficiency (PCE) of 47% under continuous wave (CW) mode. A maximum PCE of 50% is obtained at the 300 mA injection current. A very low vertical far field divergence of 9.4° is obtained at 100 mA injection. At 500 mA injection, the vertical far field divergence increases to 11°, the beam quality factors M2 values are 1.707 in vertical direction and 1.769 in lateral direction.

Four two-dimensional ternary selenides based on group 13 and 14 metals: Syntheses, crystal structures, and electrochemical properties

NASA Astrophysics Data System (ADS)

Wang, Jingrui; Li, Peng; Cai, Ting; Yang, Dan-Dan; Xiong, Wei-Wei

2018-07-01

A series of two-dimensional ternary selenides, [NH4]2[Ga2Sn2Se8] (1), [NH4]2[In2Ge2Se8] (2), [NH4]2[In2Sn2Se8] (3), [NH4]2[Ga2Ge2Se8] (4), have been solvothermally synthesized and characterized by single crystal X-ray diffraction, energy dispersive X-ray (EDX) spectroscopy, solid-state UV-Vis diffuse reflectance spectroscopy, and thermogravimetric analyses. The solid-state optical absorption spectra indicated that these compounds were semiconductors with band gaps of 1.71 eV for 1, 1.95 eV for 2, 1.85 eV for 3, and 1.83 eV for 4. In addition, compound 2 was employed as an anode material for lithium ion battery application, which exhibited a high specific capacity of 479 mA h g-1 over 200 cycles at a current density of 200 mA g-1, and an excellent rate capability of 425.2 mA h g-1 at a current density of 1000 mA g-1. Our results suggest that crystalline chalcogenides could be an alternative anode material for high performance LIBs application.

Do Medicare Advantage Plans Minimize Costs? Investigating the Relationship Between Benchmarks, Costs, and Rebates.

PubMed

Zuckerman, Stephen; Skopec, Laura; Guterman, Stuart

2017-12-01

Medicare Advantage (MA), the program that allows people to receive their Medicare benefits through private health plans, uses a benchmark-and-bidding system to induce plans to provide benefits at lower costs. However, prior research suggests medical costs, profits, and other plan costs are not as low under this system as they might otherwise be. To examine how well the current system encourages MA plans to bid their lowest cost by examining the relationship between costs and bonuses (rebates) and the benchmarks Medicare uses in determining plan payments. Regression analysis using 2015 data for HMO and local PPO plans. Costs and rebates are higher for MA plans in areas with higher benchmarks, and plan costs vary less than benchmarks do. A one-dollar increase in benchmarks is associated with 32-cent-higher plan costs and a 52-cent-higher rebate, even when controlling for market and plan factors that can affect costs. This suggests the current benchmark-and-bidding system allows plans to bid higher than local input prices and other market conditions would seem to warrant. To incentivize MA plans to maximize efficiency and minimize costs, Medicare could change the way benchmarks are set or used.

LU60645GT and MA132843GT Catalogues of Lunar and Martian Impact Craters Developed Using a Crater Shape-based Interpolation Crater Detection Algorithm for Topography Data

NASA Technical Reports Server (NTRS)

Salamuniccar, Goran; Loncaric, Sven; Mazarico, Erwan Matias

2012-01-01

For Mars, 57,633 craters from the manually assembled catalogues and 72,668 additional craters identified using several crater detection algorithms (CDAs) have been merged into the MA130301GT catalogue. By contrast, for the Moon the most complete previous catalogue contains only 14,923 craters. Two recent missions provided higher-quality digital elevation maps (DEMs): SELENE (in 1/16° resolution) and Lunar Reconnaissance Orbiter (we used up to 1/512°). This was the main motivation for work on the new Crater Shape-based interpolation module, which improves previous CDA as follows: (1) it decreases the number of false-detections for the required number of true detections; (2) it improves detection capabilities for very small craters; and (3) it provides more accurate automated measurements of craters' properties. The results are: (1) LU60645GT, which is currently the most complete (up to D>=8 km) catalogue of Lunar craters; and (2) MA132843GT catalogue of Martian craters complete up to D>=2 km, which is the extension of the previous MA130301GT catalogue. As previously achieved for Mars, LU60645GT provides all properties that were provided by the previous Lunar catalogues, plus: (1) correlation between morphological descriptors from used catalogues; (2) correlation between manually assigned attributes and automated measurements; (3) average errors and their standard deviations for manually and automatically assigned attributes such as position coordinates, diameter, depth/diameter ratio, etc; and (4) a review of positional accuracy of used datasets. Additionally, surface dating could potentially be improved with the exhaustiveness of this new catalogue. The accompanying results are: (1) the possibility of comparing a large number of Lunar and Martian craters, of e.g. depth/diameter ratio and 2D profiles; (2) utilisation of a method for re-projection of datasets and catalogues, which is very useful for craters that are very close to poles; and (3) the extension of the previous framework for evaluation of CDAs with datasets and ground-truth catalogue for the Moon.

Modification of the argon stripping target of the tandem accelerator.

PubMed

Makarov, A; Ostreinov, Yu; Taskaev, S; Vobly, P

2015-12-01

The tandem accelerator with vacuum insulation has been proposed and developed in Budker Institute of Nuclear Physics. Negative hydrogen ions are accelerated by the positive 1MV potential of the high-voltage electrode, converted into protons in the gas stripping target inside the electrode, and then protons are accelerated again by the same potential. A stationary proton beam with 2 MeV energy, 1.6 mA current, 0.1% energy monochromaticity, and 0.5% current stability is obtained now. To conduct Boron Neutron Capture Therapy it is planned to increase the proton beam current to at least 3 mA. The paper presents the results of experimental studies clarifying the reasons for limiting the current, and gives suggestions for modifying the gas stripping target in order to increase the proton beam current along with the stability of the accelerator. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mid-Atomic-Number Cylindrical Wire Array Precursor Plasma Studies on Zebra

DOE PAGES

Stafford, A; Safronova, A. S.; Kantsyrev, V. L.; ...

2014-12-30

The precursor plasmas from low wire number cylindrical wire arrays (CWAs) were previously shown to radiate at temperatures >300 eV for Ni-60 (94% Cu and 6% Ni) wires in experiments on the 1-MA Zebra generator. Continued research into precursor plasmas has studied additional midatomic-number materials including Cu and Alumel (95% Ni, 2% Al, 2% Mn, and 1% Si) to determine if the >300 eV temperatures are common for midatomic-number materials. Additionally, current scaling effects were observed by performing CWA precursor experiments at an increased current of 1.5 MA using a load current multiplier. Our results show an increase in amore » linear radiation yield of ~50% (16 versus 10 kJ/cm) for the experiments at increased current. However, plasma conditions inferred through the modeling of X-ray time-gated spectra are very similar for the precursor plasma in both current conditions.« less

Health conditions in methamphetamine-dependent adults 3 years after treatment.

PubMed

Mooney, Larissa J; Glasner-Edwards, Suzette; Marinelli-Casey, Patricia; Hillhouse, Maureen; Ang, Alfonso; Hunter, Jeremy; Haning, William; Colescott, Paula; Ling, Walter; Rawson, Richard

2009-09-01

: Medical conditions in methamphetamine (MA) users have not been well characterized. Using both self-report and physical examination data, the aims of this study were to (1) describe the frequency of medical conditions in a sample of MA users 3 years posttreatment; (2) evaluate the association between medical conditions and MA use frequency; and (3) examine the relationship of route of administration with medical outcomes. : MA-dependent adults (N = 301) who participated in the Methamphetamine Treatment Project were interviewed and examined 3 years after treatment. Medical, demographic, and substance use characteristics were assessed using the Addiction Severity Index and Life Experiences Timeline. Current and lifetime medical conditions, electrocardiogram characteristics, and physical examination abnormalities were assessed. : Among the most frequently reported lifetime conditions were wounds and burns (40.5%, N = 122) and severe dental problems (33%, N = 99), and a significant proportion of the sample evidenced prolonged corrected QT interval (19.6%, N = 43). Although health conditions were not associated with MA use frequency during follow-up, intravenous MA use was significantly associated with missing teeth (odds ratio = 2.4; 95% confidence interval, 1.2-4.7) and hepatitis C antibodies (odds ratio = 13.1; confidence interval, 5.6-30.1). : In this sample of MA users, dental problems and corrected QT prolongation were observed at elevated rates. Although posttreatment MA use frequency was not associated with a majority of medical outcomes, intravenous MA use exacerbated risk for dental pathology and hepatitis C. Longer term follow-up research is needed to elucidate health trajectories of MA users.

Visual Memory in Methamphetamine Dependent Individuals: Deficient Strategic Control of Encoding and Retrieval

PubMed Central

Morgan, Erin E.; Woods, Steven Paul; Poquette, Amelia J.; Vigil, Ofilio; Heaton, Robert K.; Grant, Igor

2012-01-01

Objective Chronic use of methamphetamine (MA) has moderate effects on neurocognitive functions associated with frontal systems, including the executive aspects of verbal episodic memory. Extending this literature, the current study examined the effects of MA on visual episodic memory with the hypothesis that a profile of deficient strategic encoding and retrieval processes would be revealed for visuospatial information (i.e., simple geometric designs), including possible differential effects on source versus item recall. Method The sample comprised 114 MA-dependent (MA+) and 110 demographically-matched MA-nondependent comparison participants (MA−) who completed the Brief Visuospatial Memory Test – Revised (BVMT-R), which was scored for standard learning and memory indices, as well as novel item (i.e., figure) and source (i.e., location) memory indices. Results Results revealed a profile of impaired immediate and delayed free recall (p < .05) in the context of preserved learning slope, retention, and recognition discriminability in the MA+ group. The MA+ group also performed more poorly than MA− participants on Item visual memory (p < .05) but not Source visual memory (p > .05), and no group by task-type interaction was observed (p > .05). Item visual memory demonstrated significant associations with executive dysfunction, deficits in working memory, and shorter length of abstinence from MA use (p < 0.05). Conclusions These visual memory findings are commensurate with studies reporting deficient strategic verbal encoding and retrieval in MA users that are posited to reflect the vulnerability of frontostriatal circuits to the neurotoxic effects of MA. Potential clinical implications of these visual memory deficits are discussed. PMID:22311530

Composite Cathodes for Dual-Rate Li-Ion Batteries

NASA Technical Reports Server (NTRS)

Whitacre, Jay; West, William; Bugga, Ratnakumar

2008-01-01

Composite-material cathodes that enable Li-ion electrochemical cells and batteries to function at both high energy densities and high discharge rates are undergoing development. Until now, using commercially available cathode materials, it has been possible to construct cells that have either capability for high-rate discharge or capability to store energy at average or high density, but not both capabilities. However, both capabilities are needed in robotic, standby-power, and other applications that involve duty cycles that include long-duration, low-power portions and short-duration, high-power portions. The electrochemically active ingredients of the present developmental composite cathode materials are: carbon-coated LiFePO4, which has a specific charge capacity of about 160 mA h/g and has been used as a high-discharge-rate cathode material and Li[Li(0.17)Mn(0.58)Ni(0.25)]O2, which has a specific charge capacity of about 240 mA h/g and has been used as a high-energy-density cathode material. In preparation for fabricating the composite material cathode described, these electrochemically active ingredients are incorporated into two sub-composites: a mixture comprising 10 weight percent of poly(vinylidine fluoride); 10 weight percent of carbon and 80 weight percent of carbon coated LiFePO4; and, a mixture comprising 10 weight percent of PVDF, and 80 weight percent of Li[Li(0.17)Mn(0.58)Ni(0.25)]O2. In the fabrication process, these mixtures are spray-deposited onto an aluminum current collector. Electrochemical tests performed thus far have shown that better charge/discharge performance is obtained when either 1) each mixture is sprayed on a separate area of the current collector or (2) the mixtures are deposited sequentially (in contradistinction to simultaneously) on the same current-collector area so that the resulting composite cathode material consists of two different sub-composite layers.

Exfoliated-SnS2 restacked on graphene as a high-capacity, high-rate, and long-cycle life anode for sodium ion batteries

NASA Astrophysics Data System (ADS)

Liu, Yongchang; Kang, Hongyan; Jiao, Lifang; Chen, Chengcheng; Cao, Kangzhe; Wang, Yijing; Yuan, Huatang

2015-01-01

Designed as a high-capacity, high-rate, and long-cycle life anode for sodium ion batteries, exfoliated-SnS2 restacked on graphene is prepared by the hydrolysis of lithiated SnS2 followed by a facile hydrothermal method. Structural and morphological characterizations demonstrate that ultrasmall SnS2 nanoplates (with a typical size of 20-50 nm) composed of 2-5 layers are homogeneously decorated on the surface of graphene, while the hybrid structure self-assembles into a three-dimensional (3D) network architecture. The obtained SnS2/graphene nanocomposite delivers a remarkable capacity as high as 650 mA h g-1 at a current density of 200 mA g-1. More impressively, the capacity can reach 326 mA h g-1 even at 4000 mA g-1 and remains stable at ~610 mA h g-1 without fading up to 300 cycles when the rate is brought back to 200 mA g-1. The excellent electrochemical performance is attributed to the synergetic effects between the ultrasmall SnS2 and the highly conductive graphene network. The unique structure can simultaneously facilitate Na+ ion diffusion, provide more reaction sites, and suppress aggregation and volume fluctuation of the active materials during prolonged cycling.Designed as a high-capacity, high-rate, and long-cycle life anode for sodium ion batteries, exfoliated-SnS2 restacked on graphene is prepared by the hydrolysis of lithiated SnS2 followed by a facile hydrothermal method. Structural and morphological characterizations demonstrate that ultrasmall SnS2 nanoplates (with a typical size of 20-50 nm) composed of 2-5 layers are homogeneously decorated on the surface of graphene, while the hybrid structure self-assembles into a three-dimensional (3D) network architecture. The obtained SnS2/graphene nanocomposite delivers a remarkable capacity as high as 650 mA h g-1 at a current density of 200 mA g-1. More impressively, the capacity can reach 326 mA h g-1 even at 4000 mA g-1 and remains stable at ~610 mA h g-1 without fading up to 300 cycles when the rate is brought back to 200 mA g-1. The excellent electrochemical performance is attributed to the synergetic effects between the ultrasmall SnS2 and the highly conductive graphene network. The unique structure can simultaneously facilitate Na+ ion diffusion, provide more reaction sites, and suppress aggregation and volume fluctuation of the active materials during prolonged cycling. Electronic supplementary information (ESI) available: Scheme S1, Fig. S1-S4. See DOI: 10.1039/c4nr05106h

Advancing High Current Startup via Localized Helicity Injection in the PEGASUS Toroidal Experiment

NASA Astrophysics Data System (ADS)

Hinson, E. T.; Barr, J. L.; Bongard, M. W.; Burke, M. G.; Fonck, R. J.; Perry, J. M.; Redd, A. J.; Schlossberg, D. J.

2013-10-01

Non-solenoidal startup via local helicity injection (LHI) and poloidal field induction is used to produce Ip = 0 . 17 MA tokamak discharges. Impurity contamination has been reduced to negligible levels by use of conical frustum cathode geometry and local scraper limiters. Attainable currents are governed by global limits of helicity and energy balance, and Taylor relaxation. A simple lumped parameter model based on these limits is used to project discharge evolution, and indicates that attaining 1 MA in NSTX-U will require LHI-driven effective loop voltages to dominate contributions from dLp / dt . This regime contrasts with results to date and will be tested at 0.3 MA in PEGASUS with a new integrated multi-injector array. Injector impedance characteristics are consistent with magnetically-limited regimes observed in higher-power foilless diodes. Bursts of MHD are measured on time scales of order ~ 100 μ s, and correlate with rapid equilibrium changes, discrete rises in Ip, redistribution of the toroidal current, ion heating (Ti ~ 1 keV), transient drops in injector voltage, and apparent n = 1 line-tied kink activity at the injector. NIMROD simulations of high-field-side HI discharges in PEGASUS are in qualitative agreement, suggesting Ip buildup results from inward propagating toroidal current loops created by intermittent reconnection of injected current streams. Work supported by US DOE Grant DE-FG02-96ER54375.

Methamphetamine use is associated with high levels of depressive symptoms in adolescents and young adults in Rural Chiang Mai Province, Thailand.

PubMed

DiMiceli, Lauren E; Sherman, Susan G; Aramrattana, Apinun; Sirirojn, Bangorn; Celentano, David D

2016-02-19

High levels of depressive symptoms often occur among individuals that use or that are dependent on methamphetamine (MA). Thailand is currently experiencing an epidemic of MA use among youth. Understanding the nature of the relationship between depressive symptoms and MA use and identifying those most at risk can further understanding of prevention and treatment options for youth who use MA and present with depressive symptoms. In 2011, we conducted a cross sectional epidemiologic study that examined associations between MA use and high levels of depressive symptoms among adolescents and young adults aged 14-29 living in Chiang Mai province, Thailand. A combination of cluster and systematic sampling was conducted to obtain a study sample of participants actively recruited in Chiang Mai province. Depressive symptoms were measured using a Thai translation of the Centers for Epidemiologic Studies Depression scale (CES-D). The independent variables measured reported lifetime and recent MA use within the past 3 months. Multivariate logistic regression models were used to assess associations between MA use and high levels of depressive symptoms. Approximately 19% (n = 394) of the sample reported ever having consumed MA and 31% (n = 124) of lifetime users reported recent MA use within the past 3 months. Recent MA use was associated with high levels of depressive symptoms (aPOR recent use: 2.60, 95% CI: 1.20, 5.63). This is one of the first studies to examine the association between MA use and high levels of depressive symptoms in a general Thai population. The odds of having high levels of depressive symptoms was significantly greater among recent MA users compared to non-users. These findings support the need for policies, programs and interventions to prevent and treat depressive symptoms presenting among MA using Thai adolescents and young adults in rural Chiang Mai province, Thailand to aid in cessation of MA use. Furthermore, additional research is needed to investigate treatment options for adolescents and young adults in Thailand that use MA and present with high levels of depressive symptoms.

Cretaceous to Recent Asymetrical Subsidence of South American and West African Conjugate Margins

NASA Astrophysics Data System (ADS)

Kenning, J.; Mann, P.

2017-12-01

Two divergent interpretations have been proposed for South American rifted-passive margins: the "mirror hypothesis" proposes that the rifted margins form symmetrically from pure shear of the lithosphere while upper-plate-lower plate models propose that the rifted margins form asymmetrically by simple shear. Models based on seismic reflection and refraction imaging and comparison of conjugate, rifted margins generally invoke a hybrid stretching process involving elements of both end member processes along with the effects of mantle plumes active during the rift and passive margin phases. We use subsidence histories of 14, 1-7 km-deep exploration wells located on South American and West African conjugate pairs now separated by the South Atlantic Ocean, applying long-term subsidence to reveal the symmetry or asymmetry of the underlying, conjugate, rift processes. Conjugate pairs characterize the rifted margin over a distance of 3500 km and include: Colorado-South Orange, Punta Del Este-North Orange, South Pelotas-Lüderitz and the North Pelotas-Walvis Basins. Of the four conjugate pairs, more rapid subsidence on the South American plate is consistently observed with greater initial rift and syn-rift subsidence rates of >60m/Ma (compared to <15 m/Ma) between approximately 145-115 Ma. High rates of tectonically-induced subsidence >100 m/Ma are observed offshore South Africa between approximately 120-80 Ma, compatible with onset of the post-rift thermal sag phase. During this period the majority of burial is completed and rates remain low at <10 m/Ma during most of the late Cretaceous and Cenozoic. The conjugate margin of Argentina/Uruguay displays more gradual subsidence throughout the Cretaceous, consistently averaging a moderate 15-30m/Ma. By the end of this stage there is a subsequent increase to 25-60 m/Ma within the last 20 Ma, interpreted to reflect lithospheric loading due to increased sedimentation rates during the Cenozoic. This increase in subsidence rate is not seen in the African conjugate section where the majority of sediments bypassed the highly aggraded Cretaceous shelf. Initially greater on the Brazilian margin compared to Namibia, here both margins exhibit moderate-steep subsidence curves until 65-55 Ma where there is reduced subsidence during much of the Late Cretaceous until 20 Ma.

21 CFR 177.1990 - Vinylidene chloride/methyl acrylate copolymers.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Methyl Acrylate and Vinylidene Chloride Monomers in Saran MA/VDC Resins and Pellets by Headspace Gas... copolymer is not less than 50,000 when determined by gel permeation chromatography using tetrahydrofuran as... Weight Averages and Molecular Weight Distribution of Polystyrene by Liquid Exclusion Chromatography (Gel...

Synthesis and electrochemical properties of Li2/3Ni1/3Mn2/3O2 as a novel 5 V class positive electrode material for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Chiba, Kazuki; Shikano, Masahiro; Sakaebe, Hikari

2016-02-01

A lithium nickel manganese oxide, O3-Li2/3Ni1/3Mn2/3O2, is synthesized from the precursor, P3-Na2/3Ni1/3Mn2/3O2, by a Na+/Li+ ion exchange reaction using molten salt. Post-heating at 300, 400, 500, 600, and 700 °C is carried out for 5 h in air. The products are characterized by powder XRD, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), SEM, 6Li-magic-angle-spinning-NMR, and electrochemical measurements. The charge/discharge profiles of O3-Li2/3Ni1/3Mn2/3O2, thermally treated at 500 °C, show a high-potential plateau region at 4.8 V. Furthermore, sloping voltage profiles are observed at an average voltage of 3.21 V. An initial discharge capacity of 257 mA h g-1 is obtained between 2.0 and 4.8 V with a current density of 15 mA g-1 at 25 °C. This capacity corresponds to 0.90 electron transfers per formula unit. This study shows that Post-heating of O3-Li2/3Ni1/3Mn2/3O2 is effective to improve its electrochemical properties.

High rate and stable cycling of lithium metal anode

DOE PAGES

Qian, Jiangfeng; Henderson, Wesley A.; Xu, Wu; ...

2015-02-20

Lithium (Li) metal is an ideal anode material for rechargeable batteries. However, dendritic Li growth and limited Coulombic efficiency (CE) during repeated Li deposition/stripping processes have prevented the application of this anode in rechargeable Li metal batteries, especially for use at high current densities. Here, we report that the use of highly concentrated electrolytes composed of ether solvents and the lithium bis(fluorosulfonyl)imide (LiFSI) salt enables the high rate cycling of a Li metal anode at high CE (up to 99.1 %) without dendrite growth. With 4 M LiFSI in 1,2-dimethoxyethane (DME) as the electrolyte, a Li|Li cell can be cycledmore » at high rates (10 mA cm -2) for more than 6000 cycles with no increase in the cell impedance, and a Cu|Li cell can be cycled at 4 mA cm-2 for more than 1000 cycles with an average CE of 98.4%. These excellent high rate performances can be attributed to the increased solvent coordination and increased availability of Li+ concentration in the electrolyte. Lastly, further development of this electrolyte may lead to practical applications for Li metal anode in rechargeable batteries. The fundamental mechanisms behind the high rate ion exchange and stability of the electrolytes also shine light on the stability of other electrochemical systems.« less

Current Status of On-Site Wastewater Management

ERIC Educational Resources Information Center

Senn, Charles L.

1978-01-01

Wastewater management is becoming an important environmental issue nationally. This article reports the history and current status of wastewater management. Regulatory programs are discussed with specific state examples. Needs assessment is also included. (MA)

Hydrological and Vegetation Variability from Mediterranean Leaf Wax Biomarkers Before and After the Rise of East African C4 Grasslands

NASA Astrophysics Data System (ADS)

Meyers, C.; deMenocal, P. B.; Tierney, J. E.; Polissar, P. J.

2012-12-01

Terrestrial and marine paleoclimate records and changes in African fossil mammal taxa indicate that a transition towards more open, C4-dominated grasslands occurred in East Africa near 2 Ma. In contrast, the Mediterranean sapropel record documents pervasive precession-paced wet/dry cycles in the strength of the African monsoon and Nile runoff since at least the late Miocene. This study investigates whether the East African vegetation shift after 2 Ma was accompanied by a change in the monsoonal wet/dry cycle response to orbital precession forcing. We sampled eastern Mediterranean ODP Site 967 at 2-3 ka resolution in two 200 kyr intervals near 3.0 and 1.7 Ma. Nearly identical orbital configurations in these intervals allow us to compare mean conditions and orbital-paced variations before and after the 2 Ma transition. We used leaf wax biomarker concentrations and δD and δ13C compositions as proxies for monsoonal strength and vegetation type, and the δ18O composition of G. ruber as a proxy for Nile River runoff. Leaf wax biomarker concentrations varied over three orders of magnitude, with much higher concentrations in sapropels. During sapropel intervals, large-amplitude negative excursions occur in δDwax, δ13Cwax, and δ18Oruber, corresponding to a strengthened monsoon and less abundant C4 plants. Carbonate-rich intervals have positive isotope excursions indicating a weakened monsoon and more abundant C4 plants. The mean and variance of δDwax and δ13Cwax values are not significantly different between the 3.0 Ma and 1.7 Ma intervals indicating Northern Africa did not experience the vegetation and climate shifts observed in East Africa. While surprising, our finding suggests that the average monsoonal response to precession forcing, and corresponding vegetation variability, did not substantially change across the 2 Ma transition. This implies that North and East Africa exhibited different climate and vegetation behavior since 3 Ma.

Enabling cost-effective high-current burst-mode operation in superconducting accelerators

DOE PAGES

Sheffield, Richard L.

2015-06-01

Superconducting (SC) accelerators are very efficient for CW or long-pulse operation, and normal conducting (NC) accelerators are cost effective for short-pulse operation. The addition of a short NC linac section to a SC linac can correct for the energy droop that occurs when pulsed high-current operation is required that exceeds the capability of the klystrons to replenish the cavity RF fields due to the long field fill-times of SC structures, or a requirement to support a broad range of beam currents results in variable beam loading. This paper describes the implementation of this technique to enable microseconds of high beam-current,more » 90 mA or more, in a 12 GeV SC long-pulse accelerator designed for the MaRIE 42-keV XFEL proposed for Los Alamos National Laboratory.« less

Long-Term Kinetics of Serum and Xanthoma Cholesterol Radioactivity in Patients with Hypercholesterolemia

PubMed Central

Samuel, Paul; Perl, William; Holtzman, Charles M.; Rochman, Norman D.; Lieberman, Sidney

1972-01-01

In four patients with hypercholesterolemia (type II hyperlipoproteinemia) and xanthomatosis the decay of serum cholesterol specific activity was followed for 53-63 wk after pulse labeling. Specific activity of biopsied xanthoma cholesterol was measured four times in the course of the study. The xanthoma specific activity curve crossed and thereafter remained above the serum specific activity curve. The average ratio of xanthoma to serum specific activity was 4.7 at the end of the study. The final half-time of the xanthoma decay curves was significantly greater (average: 200 days) than the slowest half-time of serum specific activity decay (average: 93 days). The data were analyzed by input-output analysis and yielded the following results. The average value for the total input rate of body cholesterol (IT) (sum of dietary and biosynthesized cholesterol) was 1.29 g/day. The average size of the rapidly miscible pool of cholesterol (Ma) was 55.7 g. and of the total exchangeable body mass of cholesterol (M) 116.5 g. The average value of M - Ma (remaining exchangeable mass of cholesterol) was 60.8 g. The derived values for exchangeable masses of cholesterol, in the present patients with marked hypercholesterolemia, were significantly larger than in a group of patients with normal serum lipids in previous studies. One of the four patients died of a sudden acute myocardial infarction 53 wk after pulse labeling. Specific activity of aortic wall and atheroma cholesterol was 3.12 times that of serum. The ratio was close to 2 for adipose tissue and spleen, and was slightly above 1 or was close to unity in most other organs studied, with the exception of brain which showed a ratio of 0.19. PMID:5009114

[MaRS Project

NASA Technical Reports Server (NTRS)

Aruljothi, Arunvenkatesh

2016-01-01

The Space Exploration Division of the Safety and Mission Assurances Directorate is responsible for reducing the risk to Human Space Flight Programs by providing system safety, reliability, and risk analysis. The Risk & Reliability Analysis branch plays a part in this by utilizing Probabilistic Risk Assessment (PRA) and Reliability and Maintainability (R&M) tools to identify possible types of failure and effective solutions. A continuous effort of this branch is MaRS, or Mass and Reliability System, a tool that was the focus of this internship. Future long duration space missions will have to find a balance between the mass and reliability of their spare parts. They will be unable take spares of everything and will have to determine what is most likely to require maintenance and spares. Currently there is no database that combines mass and reliability data of low level space-grade components. MaRS aims to be the first database to do this. The data in MaRS will be based on the hardware flown on the International Space Stations (ISS). The components on the ISS have a long history and are well documented, making them the perfect source. Currently, MaRS is a functioning excel workbook database; the backend is complete and only requires optimization. MaRS has been populated with all the assemblies and their components that are used on the ISS; the failures of these components are updated regularly. This project was a continuation on the efforts of previous intern groups. Once complete, R&M engineers working on future space flight missions will be able to quickly access failure and mass data on assemblies and components, allowing them to make important decisions and tradeoffs.

Orbital, tectonic and oceanographic controls on Pliocene climate and atmospheric circulation in Arctic Norway

NASA Astrophysics Data System (ADS)

Panitz, Sina; Salzmann, Ulrich; Risebrobakken, Bjørg; De Schepper, Stijn; Pound, Matthew J.; Haywood, Alan M.; Dolan, Aisling M.; Lunt, Daniel J.

2018-02-01

During the Pliocene Epoch, a stronger-than-present overturning circulation has been invoked to explain the enhanced warming in the Nordic Seas region in comparison to low to mid-latitude regions. While marine records are indicative of changes in the northward heat transport via the North Atlantic Current (NAC) during the Pliocene, the long-term terrestrial climate evolution and its driving mechanisms are poorly understood. We present the first two-million-year-long Pliocene pollen record for the Nordic Seas region from Ocean Drilling Program (ODP) Hole 642B, reflecting vegetation and climate in Arctic Norway, to assess the influence of oceanographic and atmospheric controls on Pliocene climate evolution. The vegetation record reveals a long-term cooling trend in northern Norway, which might be linked to a general decline in atmospheric CO2 concentrations over the studied interval, and climate oscillations primarily controlled by precession (23 kyr), obliquity (54 kyr) and eccentricity (100 kyr) forcing. In addition, the record identifies four major shifts in Pliocene vegetation and climate mainly controlled by changes in northward heat transport via the NAC. Cool temperate (warmer than present) conditions prevailed between 5.03-4.30 Ma, 3.90-3.47 Ma and 3.29-3.16 Ma and boreal (similar to present) conditions predominated between 4.30-3.90 Ma, 3.47-3.29 and after 3.16 Ma. A distinct decline in sediment and pollen accumulation rates at c. 4.65 Ma is probably linked to changes in ocean currents, marine productivity and atmospheric circulation. Climate model simulations suggest that changes in the strength of the Atlantic Meridional Overturning Circulation during the Early Pliocene could have affected atmospheric circulation in the Nordic Seas region, which would have affected the direction of pollen transport from Scandinavia to ODP Hole 642B.

Adaptive Iterative Dose Reduction Using Three Dimensional Processing (AIDR3D) improves chest CT image quality and reduces radiation exposure.

PubMed

Yamashiro, Tsuneo; Miyara, Tetsuhiro; Honda, Osamu; Kamiya, Hisashi; Murata, Kiyoshi; Ohno, Yoshiharu; Tomiyama, Noriyuki; Moriya, Hiroshi; Koyama, Mitsuhiro; Noma, Satoshi; Kamiya, Ayano; Tanaka, Yuko; Murayama, Sadayuki

2014-01-01

To assess the advantages of Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D) for image quality improvement and dose reduction for chest computed tomography (CT). Institutional Review Boards approved this study and informed consent was obtained. Eighty-eight subjects underwent chest CT at five institutions using identical scanners and protocols. During a single visit, each subject was scanned using different tube currents: 240, 120, and 60 mA. Scan data were converted to images using AIDR3D and a conventional reconstruction mode (without AIDR3D). Using a 5-point scale from 1 (non-diagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for three lung zones, four patterns of lung disease (nodule/mass, emphysema, bronchiolitis, and diffuse lung disease), and three mediastinal measurements (small structure visibility, streak artifacts, and shoulder artifacts). Differences in these scores were assessed by Scheffe's test. At each tube current, scans using AIDR3D had higher scores than those without AIDR3D, which were significant for lung zones (p<0.0001) and all mediastinal measurements (p<0.01). For lung diseases, significant improvements with AIDR3D were frequently observed at 120 and 60 mA. Scans with AIDR3D at 120 mA had significantly higher scores than those without AIDR3D at 240 mA for lung zones and mediastinal streak artifacts (p<0.0001), and slightly higher or equal scores for all other measurements. Scans with AIDR3D at 60 mA were also judged superior or equivalent to those without AIDR3D at 120 mA. For chest CT, AIDR3D provides better image quality and can reduce radiation exposure by 50%.

Operation Status of the J-PARC Negative Hydrogen Ion Source

NASA Astrophysics Data System (ADS)

Oguri, H.; Ikegami, K.; Ohkoshi, K.; Namekawa, Y.; Ueno, A.

2011-09-01

A cesium-free negative hydrogen ion source driven with a lanthanum hexaboride (LaB6) filament is being operated without any serious trouble for approximately four years in J-PARC. Although the ion source is capable of producing an H- ion current of more than 30 mA, the current is routinely restricted to approximately 16 mA at present for the stable operation of the RFQ linac which has serious discharge problem from September 2008. The beam run is performed during 1 month cycle, which consisted of a 4-5 weeks beam operation and a few days down-period interval. At the recent beam run, approximately 700 h continuous operation was achieved. At every runs, the beam interruption time due to the ion source failure is a few hours, which correspond to the ion source availability of more than 99%. The R&D work is being performed in parallel with the operation in order to enhance the further beam current. As a result, the H- ion current of 61 mA with normalized rms emittance of 0.26 πmm.mrad was obtained by adding a cesium seeding system to a J-PARC test ion source which has the almost same structure with the present J-PARC ion source.

Feedbacks Among Rifting, Erosion, Lithospheric Rupture, and Crustal Recycling: From the Colorado River to the Salton Trough and Gulf of California (Invited)

NASA Astrophysics Data System (ADS)

Dorsey, R. J.; Lazear, G. D.

2013-12-01

Many studies examine the influence of climate and erosion on growth of convergent orogens, but feedbacks between tectonics and erosion in extensional and transtensional settings are less well understood. The Colorado River has delivered a huge volume of sediment to rapidly subsiding transtensional basins along the Pacific - North America plate boundary over the past ~5.5 million years. Oblique rifting, rupture, and rapid subsidence drive a newly recognized style of crustal recycling in which sediment is funneled out of the continental interior by a large river and delivered to subsiding basins where it is rapidly converted to a new generation of crust at a rifted continental margin. Transfer of crust can be tracked because the eroding source (Colorado Plateau) and depositional sinks (Salton Trough and northern Gulf of California) are intact and well preserved. Using distribution of late Miocene basalt flows and thermochronologic data, we calculate that 3.4 × 1.2 x 105 km3 of rock has been eroded from the Colorado Plateau since 10 Ma. Most of this erosion occurred starting 5.5-6.0 Ma when the river drainage became integrated and incision rates increased dramatically. Two estimates for the volume of Colorado River sediment stored in basinal sinks since ~5.5 Ma are: (1) 2.8 × 0.6 x 105 km3 assuming that crust between 5 and 10-12 km depth in the plate-boundary basins is young metasedimentary rock mixed with intrusions; or (2) 1.55 × 0.35 x 105 km3 assuming that crust below 4-5 km is thinned pre-Cenozoic crystalline rock. Significant overlap of estimate 1 with the volume eroded from the Plateau provides new support for a model of lithospheric rupture and crustal recycling in the Salton Trough and northern Gulf of California. Assuming an average density of 2.3-2.5 g/cc and the preferred volume estimate above, the total mass of crust transferred is roughly 5.1-11.5 x 1014 metric tons, representing an average annual flux of 156 × 60 Mt/yr since 5.3 Ma (when the Colorado River first arrived in the Salton Trough), or 172 × 66 Mt/yr if we assume all sediment flux took place after 4.8 Ma. The calculated long-term flux is strikingly similar to historical pre-dam sediment discharge measured at Yuma in the early 1900's (172 × 64 Mt/yr). The similarity of flux estimates suggests that rates of erosion and sediment discharge in this system have been consistent, on average, over geologic to modern timescales. We suggest that positive feedback between Late Cenozoic erosion and flexural rebound on the Colorado Plateau may act to sustain steady rates of regional erosion and sediment discharge for millions of years after integration of the Colorado River at ~5.5-6 Ma.

Cobalt-based metal organic framework with superior lithium anodic performance

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

Hu, Xiaoshi; Hu, Huiping; Li, Chao

The reversible charging of a Co-1,4-benzenedicarboxylate MOF (Co-BDC MOF) prepared via an one-pot solvothermal method was studied for use as the anode in a Li-ion cell. It was found that this MOF anode provides high reversible capacities (1090 and 611 mA h g{sup −1} at current densities of 0.2 and 1 A g{sup −1}, respectively), and an impressive rate performance. Such an outstanding Li-ion storage property has not been reported previously for the LIB anodes within the MOFs category. Ex-situ X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR) studies of this material at different state of charge suggest that cobaltmore » stays at Co{sup 2+} state during discharge/charge process, so that in this case Li{sup +} may be inserted into the organic moiety without the direct participation of cobalt ions. - Graphical abstract: Co-1,4-benzenedicarboxylate MOF, synthesized through a straightforward solvothermal method, shows outstanding lithium storage performance. - Highlights: • Co-1,4-benzenedicarboxylate MOF is synthesized by a one-pot solvothermal method. • Reversible capacity of 1090 mA h g{sup −1} is achieved at a current density of 200 mA g{sup −1}. • Reversible capacity of 611 mA h g{sup −1} is achieved at a current density of 1 A g{sup −1}. • Li-ions may be inserted into the organic moieties.« less

Relief evolution of the Continental Rift of Southeast Brazil revealed by in situ-produced 10Be concentrations in river-borne sediments

NASA Astrophysics Data System (ADS)

Salgado, André Augusto Rodrigues; Rezende, Eric de Andrade; Bourlès, Didier; Braucher, Régis; da Silva, Juliana Rodrigues; Garcia, Ricardo Alexandrino

2016-04-01

This study aims to quantify the denudation dynamics of the Brazilian passive margin along a segment of the Continental Rift of Southeast Brazil. The denudation rates of 30 basins that drain both horsts of the continental rift, including the mountain ranges of the Serra do Mar (seaside horst); and the Serra da Mantiqueira (continental horst); were derived from 10Be concentrations measured in sand-sized river sediment. The mean denudation rate ranges from 9.2 m Ma-1 on the plateau of the Serra do Mar to 37.1 m Ma-1 along the oceanic escarpment of the Serra do Mar. The seaward-facing scarps of both mountain ranges exhibit mean denudation rates that are approximately 1.5 times those of the inland-facing scarps. The escarpments of the horst nearer to the ocean (Serra do Mar) exhibit higher denudation rates (mean 30.2 m Ma-1) than the escarpments of the continental horst (Serra da Mantiqueira) (mean 16.5 m Ma-1). The parameters that impact these denudation rates include the catchment relief, the slope gradient, the rock and the climate. The incongruent combination of a mountainous landscape and moderate to low 10Be-based denudation rates averaging at ∼20 m Ma-1 suggests a reduction in intraplate tectonic activity beginning in the Middle Quaternary or earlier.

Effects of Neonatal Methamphetamine and Stress on Brain Monoamines and Corticosterone in Preweanling Rats

PubMed Central

Jablonski, Sarah A.; Graham, Devon L.; Vorhees, Charles V.; Williams, Michael T.

2017-01-01

Neonatal exposure to methamphetamine (MA) and developmental chronic stress significantly alter neurodevelopmental profiles that show a variety of long-term physiological and behavioral effects. In the current experiment, Sprague-Dawley rats were exposed to one of two housing conditions along with MA. Rats were given 0 (saline), 5, or 7.5 mg/kg MA, four times per day from postnatal day (P)11 to 15 or P11 to 20. Half of the litters were reared in cages with standard bedding and half with no bedding. Separate litters were assessed at P15 or P20 for organ weights (adrenals, spleen, thymus); corticosterone; and monoamine assessments (dopamine, serotonin, norepinephrine) and their metabolites within the neostriatum, hippocampus, and prefrontal cortex. Findings show neonatal MA altered mono-amines, corticosterone, and organ characteristics alone, and as a function of developmental age and stress compared with controls. These alterations may in part be responsible for MA and early life stress-induced long-term learning and memory deficits. PMID:27817108

Thermal management and light extraction in multi-chip and high-voltage LEDs by cup-shaped copper heat spreader technology

NASA Astrophysics Data System (ADS)

Horng, Ray-Hua; Hu, Hung-Lieh; Tang, Li-Shen; Ou, Sin-Liang

2013-03-01

For LEDs with original structure and copper heat spreader, the highest surface temperatures of 3×3 array LEDs modules were 52.6 and 42.67 °C (with 1050 mA injection current), while the highest surface temperatures of 4×4 array LEDs modules were 58.55 and 48.85 °C (with 1400 mA injection current), respectively. As the 5×5 array LEDs modules with original structure and copper heat spreader were fabricated, the highest surface temperatures at 1750 mA injection current were 68.51 and 56.73 °C, respectively. The thermal resistance of optimal LEDs array module with copper heat spreader on heat sink using compound solder is reduced obviously. On the other hand, the output powers of 3×3, 4×4 and 5×5 array LEDs modules with original structure were 3621.7, 6346.3 and 9760.4 mW at injection currents of 1050, 1400 and 1750 mA, respectively. Meanwhile, the output powers of these samples with copper heat spreader can be improved to 4098.5, 7150.3 and 10919.6 mW, respectively. The optical and thermal characteristics of array LEDs module have been improved significantly using the cup-shaped copper structure. Furthermore, various types of epoxy-packaged LEDs with cup-shaped structure were also fabricated. It is found that the light extraction efficiency of LED with semicircle package has 55% improvement as compared to that of LED with flat package. The cup-shaped copper structure was contacted directly with sapphire to enhance heat dissipation. In addition to efficient heat dissipation, the light extraction of the lateral emitting in high-power LEDs can be improved.

Oceanic dispersal, vicariance and human introduction shaped the modern distribution of the termites Reticulitermes, Heterotermes and Coptotermes.

PubMed

Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Sillam-Dussès, David; Roisin, Yves; Evans, Theodore A

2016-03-30

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermesat 59.5 Ma (49.9-69.5 Ma 95% CI), yet the oldest split within Reticulitermes(Eurasia and North America) is 16.1 Ma (13.4-19.5 Ma) and the oldest split within Heterotermes + Coptotermesis 36.0 Ma (33.9-40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives. © 2016 The Author(s).

Oceanic dispersal, vicariance and human introduction shaped the modern distribution of the termites Reticulitermes, Heterotermes and Coptotermes

PubMed Central

Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Sillam-Dussès, David; Roisin, Yves; Evans, Theodore A.

2016-01-01

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermes at 59.5 Ma (49.9–69.5 Ma 95% CI), yet the oldest split within Reticulitermes (Eurasia and North America) is 16.1 Ma (13.4–19.5 Ma) and the oldest split within Heterotermes + Coptotermes is 36.0 Ma (33.9–40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives. PMID:27030416

Virtual Network Embedding via Monte Carlo Tree Search.

PubMed

Haeri, Soroush; Trajkovic, Ljiljana

2018-02-01

Network virtualization helps overcome shortcomings of the current Internet architecture. The virtualized network architecture enables coexistence of multiple virtual networks (VNs) on an existing physical infrastructure. VN embedding (VNE) problem, which deals with the embedding of VN components onto a physical network, is known to be -hard. In this paper, we propose two VNE algorithms: MaVEn-M and MaVEn-S. MaVEn-M employs the multicommodity flow algorithm for virtual link mapping while MaVEn-S uses the shortest-path algorithm. They formalize the virtual node mapping problem by using the Markov decision process (MDP) framework and devise action policies (node mappings) for the proposed MDP using the Monte Carlo tree search algorithm. Service providers may adjust the execution time of the MaVEn algorithms based on the traffic load of VN requests. The objective of the algorithms is to maximize the profit of infrastructure providers. We develop a discrete event VNE simulator to implement and evaluate performance of MaVEn-M, MaVEn-S, and several recently proposed VNE algorithms. We introduce profitability as a new performance metric that captures both acceptance and revenue to cost ratios. Simulation results show that the proposed algorithms find more profitable solutions than the existing algorithms. Given additional computation time, they further improve embedding solutions.

Detailed view into the dynamics of the Late Miocene glaciation episode that accompanied terrestrial evolution

NASA Astrophysics Data System (ADS)

Tzanova, A.; Herbert, T.; Lawrence, K. T.; Peterson, L.; Kelly, C. S.

2015-12-01

We focus on the period of ~ 9 - 5 Ma when an episode of notably cool temperatures corresponds to evidence of high latitude Northern Hemisphere glaciation and mid-latitude terrestrial evolution. Alkenone-based sea surface temperatures (SST) from six globally distributed sites: ODP Sites 907 and 982 in the North Atlantic, ODP Site 1088 in the South Atlantic and ODP Sites 883, 884 and 887 in the North Pacific, and the Monte dei Corvi marine section in the Mediterranean unequivocally establish a dramatic, Late Miocene cold episode that persisted over approximately 2.5 Myr. In this work we establish the timing and synchronization of temperature decrease as well as rebound at orbital timescales. All sites were notably warmer than their modern annual average at ~9 Ma and exhibit sustained cooling beginning at ~8 Ma. SSTs rebound close to ~5.9 Ma at most locations suggesting that the cooling trend that began in the Late Miocene slowed down or even reversed in some locations in the Pliocene. The newly reconstructed SSTs highlight the role of cooling and an increase in equator to pole temperature gradients in terrestrial evolution at this pivotal time.

Multi-Aperture-Based Probabilistic Noise Reduction of Random Telegraph Signal Noise and Photon Shot Noise in Semi-Photon-Counting Complementary-Metal-Oxide-Semiconductor Image Sensor

PubMed Central

Ishida, Haruki; Kagawa, Keiichiro; Komuro, Takashi; Zhang, Bo; Seo, Min-Woong; Takasawa, Taishi; Yasutomi, Keita; Kawahito, Shoji

2018-01-01

A probabilistic method to remove the random telegraph signal (RTS) noise and to increase the signal level is proposed, and was verified by simulation based on measured real sensor noise. Although semi-photon-counting-level (SPCL) ultra-low noise complementary-metal-oxide-semiconductor (CMOS) image sensors (CISs) with high conversion gain pixels have emerged, they still suffer from huge RTS noise, which is inherent to the CISs. The proposed method utilizes a multi-aperture (MA) camera that is composed of multiple sets of an SPCL CIS and a moderately fast and compact imaging lens to emulate a very fast single lens. Due to the redundancy of the MA camera, the RTS noise is removed by the maximum likelihood estimation where noise characteristics are modeled by the probability density distribution. In the proposed method, the photon shot noise is also relatively reduced because of the averaging effect, where the pixel values of all the multiple apertures are considered. An extremely low-light condition that the maximum number of electrons per aperture was the only 2e− was simulated. PSNRs of a test image for simple averaging, selective averaging (our previous method), and the proposed method were 11.92 dB, 11.61 dB, and 13.14 dB, respectively. The selective averaging, which can remove RTS noise, was worse than the simple averaging because it ignores the pixels with RTS noise and photon shot noise was less improved. The simulation results showed that the proposed method provided the best noise reduction performance. PMID:29587424

Stable Carbon Isotope Enrichment Before Late Miocene and Its Iimplication for Landscape Change in the Amazon Basin

NASA Astrophysics Data System (ADS)

Lee, Y. I.; Kim, D.; Hyeong, K.; Chan Min, Y.

2016-12-01

The appearance and development of C4 plants in the Late Miocene is well-established by various lines of evidence including stable carbon isotope data, yet the stable carbon isotope change before the global vegetation change has not been reported. Prior to the C4 plant expansion, the ecosystem may have been composed of C3 plants. Here we present the content and stable carbon isotope record of black carbon (BC) in a 470-cm-long piston core retrieved from the northeastern equatorial Pacific. Although suitable age dating method is lacking for the studied core, correlation of clay mineral composition, BC content, and stable carbon isotope data with a nearby well-studied core (Kim et al., submitted) at the same latitude suggests that the studied core contains sediment older than 15 Ma (330 cm in depth) and possibly back to 25 Ma, much prior to the major diversification of C4 plants. The older sediment was derived from Southern Hemisphere. The δ13C value of BC in the oldest sediment shows a relatively high value ( -22.7 ‰ on average), similar to that of C4 expansion event, and then decreases with time till reaching normal δ13C value of C3-dominated environment (-25.3 ‰ on average) around 13 Ma. This relatively high δ13C value reflects the presence of specific ecosystem, likely Pebas wetland that dominated western Amazonia before 17 Ma, and decreasing δ13C value suggests subsequent gradual development of closed-forest ecosystem. The BC content shows an abrupt increase around 400 cm, suggesting a significant aridity event in South America. Uplift of the North Andean region at 23 Ma seems to be the likely cause of such aridity event. From these observations, we argue that by comparing with the well-studied core data environmental record provided by BC data can be used for approximate age dating of deep-sea core sediment lacking appropriate dating tools, and that carbon isotope data before C4 development event may also provide information about specific regional ecosystem

Thermochronologic constraints on post-Paleozoic tectonic evolution of the central Transantarctic Mountains, Antarctica

NASA Astrophysics Data System (ADS)

Fitzgerald, Paul G.

1994-08-01

Built upon the roots of a compressive orogenic belt of late Proterozoic-early Paleozoic age and once adjacent to North America, the present-day Transantarctic Mountains (TAM) represent a rift flank, resulting from episodic uplift in the Cretaceous and Cenozoic. Fault blocks are discernible in present-day topography and subglacial morphology. Fission track results give information on differential block movement (uplift and denudation) and are important in constraining models for the uplift of the range. Apatite fission track thermochronology on samples collected from the central TAM record a complex thermotectonic history for this region over the past 350 m.y. Apatite ages in the Miller Range vary from ˜250 to ˜350 Ma and are from an exhumed apatite partial annealing zone formed following cooling of Cambro-Ordovician granitoids. A period of Cretaceous denudation (≲2 km), beginning at ˜115 Ma, is recorded at Moody Nunatak on the inland side of the TAM. Near the coast, samples along the Beardmore Glacier record rapid cooling indicative of denudation initiated in the early Cenozoic (˜50 Ma). The amount of uplift ˜70 km inland of the coast in the Queen Alexandra Range since the early Cenozoic is ˜7 km, with the likelihood of an additional ˜3 km at the coast. Eastward facing topographic escarpments in the Queen Alexandra Range mark the likely position of steeply dipping normal faults, which offset the apatite ages. Apatite ages on the east side of the Beardmore Glacier mouth are generally younger (average 27 Ma) than on the west side (average 33 Ma), reflecting greater denudation. Assumptions made regarding the use of an assumed paleogeothermal gradient are tested with available geologic evidence. The fission track data neither conflict with nor confirm paleobotanical evidence from the Sirius Group in the central TAM which suggests significant surface uplift (2-3 km) of the TAM since the Pliocene. Results build upon the available fission track database along the TAM and emphasize the subtle variability of uplift along the TAM due to episodic uplift involving differential block movements.

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

Deino, A.; Drake, R.; Tauxe, L.

Precise eruptive ages have been determined by the laser-fusion, single-crystal {sup 40}Ar/{sup 39}Ar method for juvenile volcanic feldspars from reworked and contaminated volcaniclastic rocks of the middle Miocene Ngorora Formation, Kenya Rift Valley. These ages range from 13.06 Ma at the base to 10.51 Ma toward the top of the type section near Kabarsero. Correlation of the local paleomagnetic stratigraphies with the geomagnetic reversal time scale yields magnetochronologic age estimates that are younger than the isotopic ages by an average of 0.18 Ma. Much of the discrepancy can be eliminated if an inferred change in sea-floor spreading rate occurred atmore » 13 Ma or earlier, rather than at 10.42 Ma as previously suggested. Sedimentation rates at Kabarsero calculated from the {sup 40}Ar/{sup 39}Ar results decrease from initial values of {approximately}25 cm/1,000 yr to {approximately}5 cm/1,000 yr toward the top of the section. The initial rapid sedimentation rates characterize the first 0.1 to 0.3 m.y. following emplacement of the underlying, voluminous, basin-filling Tiim Phonolites, indicating that the Baringo Basin at this time may not have existed as a rift valley created by extensional tectonics, but instead may have been a subsidence feature formed in response to removal of large volumes of magma from the lithosphere. A premolar tentatively identified as Proconsul sp. indet. found in the Ngorora Formation near the village of Bartabwa has been dated at {approximately}12.42 Ma, representing perhaps the last known occurrence of this genus in the fossil record.« less

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

Law, David R.; Cherinka, Brian; Yan, Renbin

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is an optical fiber-bundle integral-field unit (IFU) spectroscopic survey that is one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV). With a spectral coverage of 3622-10354 A and an average footprint of ~500 arcsec 2 per IFU the scientific data products derived from MaNGA will permit exploration of the internal structure of a statistically large sample of 10,000 low-redshift galaxies in unprecedented detail. Comprising 174 individually pluggable science and calibration IFUs with a near-constant data stream, MaNGA is expected to obtain ~100 million raw-frame spectra and ~10 millionmore » reduced galaxy spectra over the six-year lifetime of the survey. In this contribution, we describe the MaNGA Data Reduction Pipeline algorithms and centralized metadata framework that produce sky-subtracted spectrophotometrically calibrated spectra and rectified three-dimensional data cubes that combine individual dithered observations. For the 1390 galaxy data cubes released in Summer 2016 as part of SDSS-IV Data Release 13, we demonstrate that the MaNGA data have nearly Poisson-limited sky subtraction shortward of ~8500 A and reach a typical 10σ limiting continuum surface brightness μ = 23.5 AB arcsec -2 in a five-arcsecond-diameter aperture in the g-band. The wavelength calibration of the MaNGA data is accurate to 5 km s -1 rms, with a median spatial resolution of 2.54 arcsec FWHM (1.8 kpc at the median redshift of 0.037) and a median spectral resolution of σ = 72 km s -1.« less

Evaluation of a Mobile Application for Multiplier Method Growth and Epiphysiodesis Timing Predictions.

PubMed

Wagner, Pablo; Standard, Shawn C; Herzenberg, John E

The multiplier method (MM) is frequently used to predict limb-length discrepancy and timing of epiphysiodesis. The traditional MM uses complex formulae and requires a calculator. A mobile application was developed in an attempt to simplify and streamline these calculations. We compared the accuracy and speed of using the traditional pencil and paper technique with that using the Multiplier App (MA). After attending a training lecture and a hands-on workshop on the MM and MA, 30 resident surgeons were asked to apply the traditional MM and the MA at different weeks of their rotations. They were randomized as to the method they applied first. Subjects performed calculations for 5 clinical exercises that involved congenital and developmental limb-length discrepancies and timing of epiphysiodesis. The amount of time required to complete the exercises and the accuracy of the answers were evaluated for each subject. The test subjects answered 60% of the questions correctly using the traditional MM and 80% of the questions correctly using the MA (P=0.001). The average amount of time to complete the 5 exercises with the MM and MA was 22 and 8 minutes, respectively (P<0.0001). Several reports state that the traditional MM is quick and easy to use. Nevertheless, even in the most experienced hands, performing the calculations in clinical practice can be time-consuming. Errors may result from choosing the wrong formulae and from performing the calculations by hand. Our data show that the MA is simpler, more accurate, and faster than the traditional MM from a practical standpoint. Level II.

Comparison of Mechanical Axis and Dynamic Range Assessed with Weight Bearing Radiographs and Navigation System in Closed Wedge High Tibial Osteotomy

PubMed Central

Bae, Dae Kyung; Lee, Jong Whan; Cho, Seong Jin; Song, Sang Jun

2017-01-01

Purpose To compare navigation and weight bearing radiographic measurements of mechanical axis (MA) before and after closed wedge high tibial osteotomy (HTO) and to evaluate post-osteotomy changes in MA assessed during application of external varus or valgus force. Materials and Methods Data from 30 consecutive patients (30 knees) who underwent computer-assisted closed-wedge HTO were prospectively analyzed. Pre- and postoperative weight bearing radiographic evaluation of MA was performed. Under navigation guidance, pre- and post-osteotomy MA values were measured in an unloaded position. Any change in the post-osteotomy MA in response to external varus or valgus force, which was named as dynamic range, was evaluated with the navigation system. The navigation and weight bearing radiographic measurements were compared. Results Although there was a positive correlation between navigation and radiographic measurements, the reliability of navigation measurements of coronal alignment was reduced after osteotomy and wedge closing. The mean post-osteotomy MA value measured with the navigation was 3.5°±0.8° valgus in an unloaded position. It was 1.3°±0.8° valgus under varus force and 5.8°±1.1° valgus under valgus force. The average dynamic range was >±2°. Conclusions Potential differences between the postoperative MAs assessed by weight bearing radiographs and the navigation system in unloaded position should be considered during computer-assisted closed wedge HTO. Care should be taken to keep the dynamic range within the permissible range of alignment goal in HTO. PMID:28854769

The Development of Morphological Awareness in Young Bilinguals: Effects of Age and L1 Background

ERIC Educational Resources Information Center

Lam, Boji Pak-Wing; Sheng, Li

2016-01-01

Purpose: Current understanding about the effect of first language (L1) background on morphological awareness (MA) development in those who are bilingual is largely limited to school-aged second-language learners. This study examined the development of MA in bilingual Mandarin-English (ManEngBi) and Spanish-English (SpaEngBi) children ages 4 to 7…

Unanticipated Effect of a Randomized Peer Network Intervention on Depressive Symptoms among Young Methamphetamine Users in Thailand

ERIC Educational Resources Information Center

German, D.; Sutcliffe, C. G.; Sirirojn, B.; Sherman, S. G.; Latkin, C. A.; Aramrattana, A.; Celentano, D. D.

2012-01-01

We examined the effect on depressive symptoms of a peer network-oriented intervention effective in reducing sexual risk behavior and methamphetamine (MA) use. Current Thai MA users aged 18-25 years and their drug and/or sex network members enrolled in a randomized controlled trial with 4 follow-ups over 12 months. A total of 415 index participants…

Characterization of the IOTA Proton Source

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

Young, Samantha

2017-08-11

This project focuses on characterizing the IOTA proton source through changing the parameters of four various components of the Low Energy Beam Transport (LEBT). Because of an inecient lament, current was limited to 2 mA when 40 mA is ultimately desired. Through an investigation of the solenoids and trims of the LEBT, we sought more knowledge about the optimum settings for running the IOTA proton source.

Electrocatalytic activity of cobalt phosphide-modified graphite felt toward VO2+/VO2+ redox reaction

NASA Astrophysics Data System (ADS)

Ge, Zhijun; Wang, Ling; He, Zhangxing; Li, Yuehua; Jiang, Yingqiao; Meng, Wei; Dai, Lei

2018-04-01

A novel strategy for improving the electro-catalytic properties of graphite felt (GF) electrode in vanadium redox flow battery (VRFB) is designed by depositing cobalt phosphide (CoP) onto GF surface. The CoP powder is synthesized by direct carbonization of Co-based zeolitic imidazolate framework (ZIF-67) followed by phosphidation. Cyclic voltammetry results confirm that the CoP-modified graphite felt (GF-CoP) electrode has excellent reversibility and electro-catalytic activity to the VO2+/VO2+ cathodic reaction compared with the pristine GF electrode. The cell using GF-CoP electrode shows apparently higher discharge capacity over that based on GF electrode. The cell using GF-CoP electrode has the capacity of 67.2 mA h at 100 mA cm-2, 32.7 mA h larger than that using GF electrode. Compared with cell using GF electrode, the voltage efficiency of the cell based on GF-CoP electrode increases by 5.9% and energy efficiency by 5.4% at a current density of 100 mA cm-2. The cell using GF-CoP electrode can reach 94.31% capacity retention after 50 cycles at a current density of 30 mA cm-2. The results show that the CoP can effectively promote the VO2+/VO2+ redox reaction, implying that metal phosphides are a new kind of potential catalytic materials for VRFB.

Automatic tube current modulation technique for multidetector CT: is it effective with a 64-detector CT?

PubMed

Funama, Yoshinori; Awai, Kazuo; Hatemura, Masahiro; Shimamura, Masamitchi; Yanaga, Yumi; Oda, Seitaro; Yamashita, Yasuyuki

2008-01-01

To investigate whether it is possible to obtain adequate images at uniform image noise levels and reduced radiation exposure with our automatic tube current modulation (ATCM) technique for 64-detector CT. The study population consisted of 64 patients with known or suspected lung or abdominal disease. We used a 64-detector CT scanner (LightSpeed VCT, GE Healthcare, Waukesha, WI, USA) and a combined angular and longitudinal tube current modulation technique (Smart mA, GE Healthcare, Waukesha, WI, USA) to examine 34 patients. The scanning parameters were identical; the minimum and maximum tube current thresholds were 50 and 800 mA, respectively. For study of the constant tube current technique, 30 additional patients were examined at 350 mA. The CT number and image noise (SD of the CT number) were measured in the 64 patients at six levels, i.e., the center of the left ventricle, the liver dome, the porta hepatis, the center of the spleen and the right and left renal pelvis. When we used the ATCM technique, the mean image noise ranged from 8.40 at the center of the left ventricle to 11.31 at the porta hepatis; the mean tube current ranged from 105.9 mAs at the center of the left ventricle to 169.6 mAs at the center of the spleen. The mean dose reduction rate per constant tube current at 175 mAs ranged from 3.1 to 39.5%. By use of the ATCM technique, it is possible to maintain a constant image noise level with a 64-detector CT.

Production and characterization of thermoplastic cassava starch, functionalized poly(lactic acid), and their reactive compatibilized blends

NASA Astrophysics Data System (ADS)

Detyothin, Sukeewan

Cassava starch was blended with glycerol using a co-rotating twin-screw extruder (TSE). Thermoplastic cassava starch (TPCS) at a ratio of 70/30 by weight of cassava/glycerol was selected and further blended with other polymers. TPCS sheets made from compression molding had low tensile strength (0.45 +/- 0.05 MPa) and Young's modulus (1.24 +/- 0.58 MPa), but moderate elongation at break (83.0 +/- 0.18.6%), medium level of oxygen permeability, and high water vapor permeability with a very high rate of water absorption. TPCS was blended with poly(lactic acid) (PLA) at various ratios by using a TSE. The blend resins exhibited good properties such as increased thermal stability (Tmax) and crystallinity of PLA, and improved water sensitivity and processability of TPCS. PLA and TPCS exhibited a high interfacial tension between the two phases of 7.9 mJ·m -2, indicating the formation of an incompatible, immiscible blend. SEM micrographs showed a non-homogeneous distribution of TPCS droplets in the PLA continuous phase. TEM micrographs of the blend films made by cast-film extrusion showed coalescence of the TPCS droplets in the PLA continuous phase of the blend, indicating that the compatibility between the polymer pair needs to be improved. A response surface methodology (RSM) design was used to analyze the effects of maleic anhydride (MA) and 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (Luperox or L101) contents, and TSE screw speed on the degree of grafted MA and number average molecular weight (Mn) of functionalized PLA (PLA-g-MA), a reactive compatibilizer. PLA-g- MA made by reactive extrusion had an array of colors depending on the content of L101 and MA used. New FTIR peaks suggested that MA was grafted onto the PLA backbone and oligomeric MA may occur. Increasing L101 increased the degree of grafting and decreased Mn, but the Mn of the PLA-g-MA's produced with a high amount of L101 was stable during storage. MA exhibited an optimum concentration for maximizing the degree of grafted MA, and increasing MA content retarded the reduction of Mn during processing. However, the Mn of PLA-g-MA during storage decreased more rapidly with a high content of MA. TSE screw speed had an impact on the Mn with the maximum value predicted at 20 rpm. PLA-g-MA compounds differing in Mn and/or grafted MA content were used as reactive polymers with TPCS (to produce binary blends) and as reactive compatibilizers (to produce ternary blends of PLA/TPCS/PLA-g-MA) with TPCS content of 30 wt% using a TSE. As a result of maleation, PLA-g-MA had a higher grafted MA content with a lower Mn, and higher PI. The interaction of anhydride groups from PLA-g-MA and hydroxyl groups from TPCS was found by FTIR. The reactive binary blends exhibited a change in thermal stability, decrease of Tcc, the presence of double melting peaks, and an increase of the Tgs of glycerol and starch. The higher the grafted MA content and/or the higher Mn of the PLA- g-MA used, the better were the distribution and smaller the TPCS domains obtained in the blends. The highest elongation at break was achieved when 30 wt% TPCS was blended with 70 wt% of PLA having 0.1 wt% of grafted MA and Mn of PLA-g-MA with a 45 kDa. Finally, the optimum PLA-g-MA was determined by using the results from PLA-g-MA RSM design and the reactive blending.

The high-βN hybrid scenario for ITER and FNSF steady-state missions

DOE PAGES

Turco, Francesca; Petty, Clinton C.; Luce, Timothy C.; ...

2015-05-15

New experiments on DIII-D have demonstrated the steady-state potential of the hybrid scenario, with 1 MA of plasma current driven fully non-inductively and βN up to 3.7 sustained for ~3 s (~1.5 current diffusion time, τ R, in DIII-D), providing the basis for an attractive option for steady-state operation in ITER and FNSF. Excellent confinement is achieved (H 98y2~1.6) without performance limiting tearing modes. Furthermore, the hybrid regime overcomes the need for off-axis current drive efficiency, taking advantage of poloidal magnetic flux pumping that is believed to be the result of a saturated 3/2 tearing mode. This allows for efficientmore » current drive close to the axis, without deleterious sawtooth instabilities. In these experiments, the edge surface loop voltage is driven down to zero for >1 τ R when the poloidal β is increased above 1.9 at a plasma current of 1.0 MA and the ECH power is increased to 3.2 MW. Stationary operation of hybrid plasmas with all on-axis current drive is sustained at pressures slightly above the ideal no-wall limit, while the calculated ideal with-wall MHD limit is β N~4-4.5. Off-axis NBI power has been used to broaden the pressure and current profiles in this scenario, seeking to take advantage of higher predicted kink stability limits and lower values of the tearing stability index Δ', as calculated by the DCON and PEST3 codes. Our results are based on measured profiles that predict ideal limits at βN>4.5, 10% higher than the cases with on-axis NBI. A 0-D model, based on the present confinement, βN and shape values of the DIII-D hybrid scenario, shows that these plasmas are consistent with the ITER 9 MA, Q=5 mission and the FNSF 6.7 MA scenario with Q=3.5. With collisionality and edge safety factor values comparable to those envisioned for ITER and FNSF, the high-βN hybrid represents an attractive high performance option for the steady-state missions of these devices.« less

Intensity dynamics in a waveguide array laser

NASA Astrophysics Data System (ADS)

Feng, Mingming; Williams, Matthew O.; Kutz, J. Nathan; Silverman, Kevin L.; Mirin, Richard P.; Cundiff, Steven T.

2011-02-01

We consider experimentally and theoretically the optical field dynamics of a five-emitter laser array subject to a ramped injection current. We have achieved experimentally an array that produces a robust oscillatory power output with a nearly constant π phase shift between the oscillations from each waveguide. The output power also decreases linearly as a function of waveguide number. Those behaviors persisted for pump currents varying between 380 and 500 mA with only a slight change in phase. Of note is the fact that the fundamental frequency of oscillation increases with injection current, and higher harmonics are produced above a threshold current of approximately 380 mA. Experimental observations and theoretical predictions are in agreement. A low dimensional model was also developed and the impact of the nonuniform injection current studied. A nonuniform injection current is capable of shifting the bifurcations of the waveguide array providing a valuable method of array tuning without additional gain or structural alterations to the array.

Flexible, 31 channel breast coil for enhanced parallel imaging performance at 3T

PubMed Central

Hancu, Ileana; Fiveland, Eric; Park, Keith; Giaquinto, Randy O.; Rohling, Kenneth; Wiesinger, Florian

2015-01-01

Purpose To design, build and characterize the performance of a novel 3T, 31 channel breast coil. Methods A flexible breast coil, accommodating all breast sizes while preserving close to unity filling factors in all configurations, was designed and built. Its performance was compared to the performance of the current state-of-the-art, 16 channel breast coil (Sentinelle coil, Hologic, Bedford, MA, USA), in phantoms and in vivo. Results Better axilla coverage and lower inter-coil coupling (12% vs. 26%, as characterized by the average off-diagonal elements of the noise correlation matrix) was exhibited by our 31 channel coil compared to the 16 channel coil. Breast area SNR increases of 68% (phantom) and 28 ± 31% (in vivo) were demonstrated in the 3 volunteers studied when the 31 channel coil was used. For the 31 channel/16 channel arrays, respectively, two dimensional acceleration factors of L/R × S/I = 4.3 × 2.4 resulted in average g-factors of 1.10/1.68 (in vitro) and 1.28/2.75 (in vivo); acceleration factors of L/R × A/P = 3.0 × 2.8 resulted in average g-factors of 1.06/1.54 (in vitro) and 1.05/1.12 (in vivo). Conclusion A high performance breast coil was built; its capabilities were demonstrated in phantom and normal volunteer imaging experiments. PMID:25772214

Computational estimation of magnetically induced electric fields in a rotating head

NASA Astrophysics Data System (ADS)

Ilvonen, Sami; Laakso, Ilkka

2009-01-01

Change in a magnetic field, or similarly, movement in a strong static magnetic field induces electric fields in human tissues, which could potentially cause harmful effects. In this paper, the fields induced by different rotational movements of a head in a strong homogeneous magnetic field are computed numerically. Average field magnitudes near the retinas and inner ears are studied in order to gain insight into the causes of phosphenes and vertigo-like effects, which are associated with extremely low-frequency (ELF) magnetic fields. The induced electric fields are calculated in four different anatomically realistic head models using an efficient finite-element method (FEM) solver. The results are compared with basic restriction limits by IEEE and ICNIRP. Under rotational movement of the head, with a magnetic flux rate of change of 1 T s-1, the maximum IEEE-averaged electric field and maximum ICNIRP-averaged current density were 337 mV m-1 and 8.84 mA m-2, respectively. The limits by IEEE seem significantly stricter than those by ICNIRP. The results show that a magnetic flux rate of change of 1 T s-1 may induce electric field in the range of 50 mV m-1 near retinas, and possibly even larger values near the inner ears. These results provide information for approximating the threshold electric field values of phosphenes and vertigo-like effects.

Fluctuations in the East Asian monsoon recorded by pollen assemblages in sediments from the Japan Sea off the southwestern coast of Hokkaido, Japan, from 4.3 Ma to the present

NASA Astrophysics Data System (ADS)

Igarashi, Yaeko; Irino, Tomohisa; Sawada, Ken; Song, Lu; Furota, Satoshi

2018-04-01

We reconstructed fluctuations in the East Asian monsoon and vegetation in the Japan Sea region since the middle Pliocene based on pollen data obtained from sediments collected by the Integrated Ocean Drilling Program off the southwestern coast of northern Japan. Taxodiaceae conifers Metasequoia and Cryptomeria and Sciadopityacere conifer Sciadopitys are excellent indicators of a humid climate during the monsoon. The pollen temperature index (Tp) can be used as a proxy for relative air temperature. Based on changes in vegetation and reconstructed climate over a period of 4.3 Ma, we classified the sediment sequence into six pollen zones. From 4.3 to 3.8 Ma (Zone 1), the climate fluctuated between cool/moist and warm/moist climatic conditions. Vegetation changed between warm temperate mixed forest and cool temperate conifer forest. The Neogene type tree Carya recovered under a warm/moist climate. The period from 3.8 to 2.5 Ma (Zone 2) was characterized by increased Metasequoia pollen concentration. Warm temperate mixed forest vegetation developed under a cool/moist climate. The period from 2.5 to 2.2 Ma (Zone 3) was characterized by an abrupt increase in Metasequoia and/or Cryptomeria pollen and a decrease in warm broadleaf tree pollen, indicating a cool/humid climate. The Zone 4 period (2.2-1.7 Ma) was characterized by a decrease in Metasequoia and/or Cryptomeria pollen and an increase in cool temperate conifer Picea and Tsuga pollen, indicating a cool/moist climate. The period from 1.7 to 0.3 Ma (Zone 5) was characterized by orbital-scale climate fluctuations. Cycles of abrupt increases and decreases in Cryptomeria and Picea pollen and in Tp values indicated changes between warm/humid and cold/dry climates. The alpine fern Selaginella selaginoides appeared as of 1.6 Ma. Vegetation alternated among warm mixed, cool mixed, and cool temperate conifer forests. Zone 6 (0.3 Ma to present) was characterized by a decrease in Cryptomeria pollen. The warm temperate broadleaf forest and cool temperate conifer forest developed alternately under warm/moist and cold/dry climate. Zone 2 corresponded to a weak Tsushima Current breaking through the Tsushima Strait, and the beginning of orbital-scale climatic changes at 1.7 Ma during Zone 5 corresponded to the strong inflow of the Tsushima Current into the Japan Sea during interglacial periods (Gallagher et al., 2015).

Characterization of the starch-acting MaAmyB enzyme from Microbacterium aurum B8.A representing the novel subfamily GH13_42 with an unusual, multi-domain organization

PubMed Central

Valk, Vincent; van der Kaaij, Rachel M.; Dijkhuizen, Lubbert

2016-01-01

The bacterium Microbacterium aurum strain B8.A degrades granular starches, using the multi-domain MaAmyA α-amylase to initiate granule degradation through pore formation. This paper reports the characterization of the M. aurum B8.A MaAmyB enzyme, a second starch-acting enzyme with multiple FNIII and CBM25 domains. MaAmyB was characterized as an α-glucan 1,4-α-maltohexaosidase with the ability to subsequently hydrolyze maltohexaose to maltose through the release of glucose. MaAmyB also displays exo-activity with a double blocked PNPG7 substrate, releasing PNP. In M. aurum B8.A, MaAmyB may contribute to degradation of starch granules by rapidly hydrolyzing the helical and linear starch chains that become exposed after pore formation by MaAmyA. Bioinformatics analysis showed that MaAmyB represents a novel GH13 subfamily, designated GH13_42, currently with 165 members, all in Gram-positive soil dwelling bacteria, mostly Streptomyces. All members have an unusually large catalytic domain (AB-regions), due to three insertions compared to established α-amylases, and an aberrant C-region, which has only 30% identity to established GH13 C-regions. Most GH13_42 members have three N-terminal domains (2 CBM25 and 1 FNIII). This is unusual as starch binding domains are commonly found at the C-termini of α-amylases. The evolution of the multi-domain M. aurum B8.A MaAmyA and MaAmyB enzymes is discussed. PMID:27808246

Conjugated fatty acids and methane production by rumen microbes when incubated with linseed oil alone or mixed with fish oil and/or malate.

PubMed

Li, Xiang Z; Gao, Qing S; Yan, Chang G; Choi, Seong H; Shin, Jong S; Song, Man K

2015-08-01

We hypothesized that manipulating metabolism with fish oil and malate as a hydrogen acceptor would affect the biohydrogenation process of α-linolenic acid by rumen microbes. This study was to examine the effect of fish oil and/or malate on the production of conjugated fatty acids and methane (CH4 ) by rumen microbes when incubated with linseed oil. Linseed oil (LO), LO with fish oil (LO-FO), LO with malate (LO-MA), or LO with fish oil and malate (LO-FO-MA) was added to diluted rumen fluid, respectively. The LO-MA and LO-FO-MA increased pH and propionate concentration compared to the other treatments. LO-MA and LO-FO-MA reduced CH4 production compared to LO. LO-MA and LO-FO-MA increased the contents of c9,t11-conjugated linoleic acid (CLA) and c9,t11,c15-conjugated linolenic acid (CLnA) compared to LO. The content of malate was rapidly reduced while that of lactate was reduced in LO-MA and LO-FO-MA from 3 h incubation time. The fold change of the quantity of methanogen related to total bacteria was decreased at both 3 h and 6 h incubation times in all treatments compared to the control. Overall data indicate that supplementation of combined malate and/or fish oil when incubated with linseed oil, could depress methane generation and increase production of propionate, CLA and CLnA under the conditions of the current in vitro study. © 2015 Japanese Society of Animal Science.

Synthesis of nanostructured materials by using metal-cyanide coordination polymers and their lithium storage properties

NASA Astrophysics Data System (ADS)

Nie, Ping; Shen, Laifa; Luo, Haifeng; Li, Hongsen; Xu, Guiyin; Zhang, Xiaogang

2013-10-01

Herein, we demonstrate a novel and simple two-step process for preparing LiCoO2 nanocrystals by using a Prussian blue analogue Co3[Co(CN)6]2 as a precursor. The resultant LiCoO2 nanoparticles possess single crystalline nature and good uniformity with an average size of ca. 360 nm. The unique nanostructure of LiCoO2 provides relatively shorter Li+ diffusion pathways, thus facilitating the fast kinetics of electrochemical reactions. As a consequence, high reversible capacity, excellent cycling stability and rate capability are achieved with these nanocrystals as cathodes for lithium storage. The LiCoO2 nanocrystals deliver specific capacities of 154.5, 135.8, 119, and 100.3 mA h g-1 at 0.2, 0.4, 1, and 2 C rates, respectively. Even at a high current density of 4 C, a reversible capacity of 87 mA h g-1 could be maintained. Importantly, a capacity retention of 83.4% after 100 cycles is achieved at a constant discharge rate of 1 C. Furthermore, owing to facile control of the morphology and size of Prussian blue analogues by varying process parameters, as well as the tailored design of multi-component metal-cyanide hybrid coordination polymers, with which we have successfully prepared porous Fe2O3@NixCo3-xO4 nanocubes, one of the potential anode materials for lithium-ion batteries, such a simple and scalable approach could also be applied to the synthesis of other nanomaterials for energy storage devices.Herein, we demonstrate a novel and simple two-step process for preparing LiCoO2 nanocrystals by using a Prussian blue analogue Co3[Co(CN)6]2 as a precursor. The resultant LiCoO2 nanoparticles possess single crystalline nature and good uniformity with an average size of ca. 360 nm. The unique nanostructure of LiCoO2 provides relatively shorter Li+ diffusion pathways, thus facilitating the fast kinetics of electrochemical reactions. As a consequence, high reversible capacity, excellent cycling stability and rate capability are achieved with these nanocrystals as cathodes for lithium storage. The LiCoO2 nanocrystals deliver specific capacities of 154.5, 135.8, 119, and 100.3 mA h g-1 at 0.2, 0.4, 1, and 2 C rates, respectively. Even at a high current density of 4 C, a reversible capacity of 87 mA h g-1 could be maintained. Importantly, a capacity retention of 83.4% after 100 cycles is achieved at a constant discharge rate of 1 C. Furthermore, owing to facile control of the morphology and size of Prussian blue analogues by varying process parameters, as well as the tailored design of multi-component metal-cyanide hybrid coordination polymers, with which we have successfully prepared porous Fe2O3@NixCo3-xO4 nanocubes, one of the potential anode materials for lithium-ion batteries, such a simple and scalable approach could also be applied to the synthesis of other nanomaterials for energy storage devices. Electronic supplementary information (ESI) available: Detailed experimental procedures and supplementary figures. See DOI: 10.1039/c3nr03289b

Adaptive statistical iterative reconstruction and Veo: assessment of image quality and diagnostic performance in CT colonography at various radiation doses.

PubMed

Yoon, Min A; Kim, Se Hyung; Lee, Jeong Min; Woo, Hyoun Sik; Lee, Eun Sun; Ahn, Se Jin; Han, Joon Koo

2012-01-01

To evaluate the diagnostic performance of computed tomography (CT) colonography (CTC) reconstructed with different levels of adaptive statistical iterative reconstruction (ASiR, GE Healthcare) and Veo (model-based iterative reconstruction, GE Healthcare) at various tube currents in detection of polyps in porcine colon phantoms. Five porcine colon phantoms with 46 simulated polyps were scanned at different radiation doses (10, 30, and 50 mA s) and were reconstructed using filtered back projection (FBP), ASiR (20%, 40%, and 60%) and Veo. Eleven data sets for each phantom (10-mA s FBP, 10-mA s 20% ASiR, 10-mA s 40% ASiR, 10-mA s 60% ASiR, 10-mA s Veo, 30-mA s FBP, 30-mA s 20% ASiR, 30-mA s 40% ASiR, 30-mA s 60% ASiR, 30-mA s Veo, and 50-mA s FBP) yielded a total of 55 data sets. Polyp detection sensitivity and confidence level of 2 independent observers were evaluated with the McNemar test, the Fisher exact test, and receiver operating characteristic curve analysis. Comparative analyses of overall image quality score, measured image noise, and interpretation time were also performed. Per-polyp detection sensitivities and specificities were highest in 10-mA s Veo, 30-mA s FBP, 30-mA s 60% ASiR, and 50-mA s FBP (sensitivity, 100%; specificity, 100%). The area-under-the-curve values for the overall performance of each data set was also highest (1.000) at 50-mA s FBP, 30-mA s FBP, 30-mA s 60% ASiR, and 10-mA s Veo. Images reconstructed with ASiR showed statistically significant improvement in per-polyp detection sensitivity as the percent level of per-polyp sensitivity increased (10-mA s FBP vs 10-mA s 20% ASiR, P = 0.011; 10-mA s FBP vs 10-mA s 40% ASiR, P = 0.000; 10-mA s FBP vs 10-mA s 60% ASiR, P = 0.000; 10-mA s 20% ASiR vs 40% ASiR, P = 0.034). Overall image quality score was highest at 30-mA s Veo and 50-mA s FBP. The quantitative measurement of the image noise was lowest at 30-mA s Veo and second lowest at 10-mA s Veo. There was a trend of decrease in time required for image interpretation as the percent level of ASiR increased, and ASiR or Veo was used instead of FBP. However, differences from comparative analyses of overall image quality score, measured image noise, and interpretation time did not reach statistical significance. ASiR and Veo showed improved diagnostic performance with excellent sensitivity and specificity with less image noise and good image quality compared with FBP reconstruction of same radiation dose. Our study confirmed feasibility of low-dose CTC with iterative reconstruction as a promising screening tool with excellent diagnostic performance similar to that of the standard-dose CTC with FBP.

Steady 10Be-derived paleoerosion rates across the Plio-Pleistocene climate transition, Fish Creek-Vallecito basin, California

NASA Astrophysics Data System (ADS)

Oskin, M. E.; Longinotti, N. E.; Peryam, T. C.; Dorsey, R. J.; DeBoer, C. J.; Housen, B. A.; Blisniuk, K. D.

2017-09-01

Rates of erosion over time provide a valuable tool for gauging tectonic and climatic drivers of landscape evolution. Here we measure 10Be archived in quartz sediment from the Fish Creek-Vallecito basin to resolve a time series of catchment-averaged erosion rates and to test the hypothesis that aridity and increased climate variation after approximately 3 Ma led to an increase in erosion rates in this semiarid, ice-free setting. The Fish Creek-Vallecito basin, located east of the Peninsular Ranges in Southern California, is an ideal setting to derive a Plio-Pleistocene paleoerosion rate record. The basin has a rapid sediment accumulation rate, a detailed magnetostratigraphic age record, and its stratigraphy has been exposed through recent, rapid uplift and erosion. A well-defined source region of uniform lithology and low erosion rate provides a high, reproducible 10Be signal. We find that paleoerosion rates were remarkably consistent between 1 and 4 Ma, averaging 38 ± 24 m/Myr (2σ). Modern catchment-averaged erosion rates are similar to the paleoerosion rates. The uniformity of erosion over the past 4 Myr indicates that the landscape was not significantly affected by late Pliocene global climate change, nor was it affected by a local long-term increase in aridity.

Embedding ultrafine ZnSnO3 nanoparticles into reduced graphene oxide composites as high-performance electrodes for lithium ion batteries

NASA Astrophysics Data System (ADS)

Ma, Yuhang; Jiang, Ranran; Li, Dan; Dong, Yutao; Liu, Yushan; Zhang, Jianmin

2018-05-01

Ultrafine ZnSnO3 nanoparticles, with an average diameter of 45 nm, homogeneously grown on reduced graphene oxide (rGO) have been successfully fabricated via methods of low temperature coprecipitation, colloid electrostatic self-assembly, and hydrothermal treatment. The uniformly distributed ZnSnO3 nanocrystals could inhibit the restacking of rGO sheets. In turn, the existence of rGO could hinder the growth and aggregation of ZnSnO3 nanoparticles in the synthesis process, increase the conductivity of the composite, and buffer the volume expansion of the ZnSnO3 nanocrystals upon lithium ion insertion and extraction. The obtained ZnSnO3/rGO exhibited superior cycling stability with a discharge/charge capacity of 718/696 mA h g-1 after 100 cycles at a current density of 0.1 A g-1.

Beam Loss Simulation and Collimator System Configurations for the Advanced Photon Source Upgrade

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

Xiao, A.; Borland, M.

The proposed multi-bend achromat lattice for the Advanced Photon Source upgrade (APS-U) has a design emittance of less than 70 pm. The Touschek loss rate is high: compared with the current APS ring, which has an average beam lifetime ~ 10 h, the simulated beam lifetime for APS-U is only ~2 h when operated in the high flux mode (I=200 mA in 48 bunches). An additional consequence of the short lifetime is that injection must be more frequent, which provides another potential source of particle loss. In order to provide information for the radiation shielding system evaluation and to avoidmore » particle loss in sensitive locations around the ring (for example, insertion device straight sections), simulations of the detailed beam loss distribution have been performed. Several possible collimation configurations have been simulated and compared.« less

Modification of polycarbonate surface in oxidizing plasma

NASA Astrophysics Data System (ADS)

Ovtsyn, A. A.; Smirnov, S. A.; Shikova, T. G.; Kholodkov, I. V.

2017-11-01

The properties of the surface of the film polycarbonate Lexan 8010 were experimentally studied after treatment in a DC discharge plasma in oxygen and air at pressures of 50-300 Pa and a discharge current of 80 mA. The contact angles of wetting and surface energies are measured. The topography of the surface was investigated by atomic force microscopy. The chemical composition of the surface was determined from the FT-IR spectroscopy data in the variant of total internal reflection, as well as X-ray photoelectron spectroscopy. Treatment in the oxidizing plasma leads to a change in morphology (average roughness increases), an increase in the surface energy, and the concentration of oxygen-containing groups (hydroxyl groups, carbonyl groups in ketones or aldehydes and in oxyketones) on the surface of the polymer. Possible reasons for the difference in surface properties of polymer under the action of oxygen and air plasma on it are discussed.

Scaling magnetized liner inertial fusion on Z and future pulsed-power accelerators

DOE PAGES

Slutz, Stephen A.; Stygar, William A.; Gomez, Matthew R.; ...

2016-02-04

In this study, the MagLIF (Magnetized Liner Inertial Fusion) concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] has demonstrated fusion–relevant plasma conditions [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z accelerator with a peak drive current of about 18 MA. We present 2D numerical simulations of the scaling of MagLIF on Z as a function of drive current, preheat energy, and applied magnetic field. The results indicate that deuterium-tritium (DT) fusion yields greater than 100 kJ could be possible on Z when all of these parameters are at the optimum values:more » i.e., peak current = 25 MA, deposited preheat energy = 5 kJ, and B z = 30 T. Much higher yields have been predicted [S. A. Slutz and R. A. Vesey, Phys. Rev. Lett. 108, 025003 (2012)] for MagLIF driven with larger peak currents. Two high performance pulsed-power accelerators (Z300 and Z800) based on linear-transformer-driver technology have been designed [W. A. Stygar et al., Phys. Rev. ST Accel. Beams 18, 110401 (2015)]. The Z300 design would provide 48 MA to a MagLIF load, while Z800 would provide 65 MA. Parameterized Thevenin-equivalent circuits were used to drive a series of 1D and 2D numerical MagLIF simulations with currents ranging from what Z can deliver now to what could be achieved by these conceptual future pulsed-power accelerators. 2D simulations of simple MagLIF targets containing just gaseous DT have yields of 18 MJ for Z300 and 440 MJ for Z800. The 2D simulated yield for Z800 is increased to 7 GJ by adding a layer of frozen DT ice to the inside of the liner.« less

Scaling magnetized liner inertial fusion on Z and future pulsed-power accelerators

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

Slutz, Stephen A.; Stygar, William A.; Gomez, Matthew R.

In this study, the MagLIF (Magnetized Liner Inertial Fusion) concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] has demonstrated fusion–relevant plasma conditions [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z accelerator with a peak drive current of about 18 MA. We present 2D numerical simulations of the scaling of MagLIF on Z as a function of drive current, preheat energy, and applied magnetic field. The results indicate that deuterium-tritium (DT) fusion yields greater than 100 kJ could be possible on Z when all of these parameters are at the optimum values:more » i.e., peak current = 25 MA, deposited preheat energy = 5 kJ, and B z = 30 T. Much higher yields have been predicted [S. A. Slutz and R. A. Vesey, Phys. Rev. Lett. 108, 025003 (2012)] for MagLIF driven with larger peak currents. Two high performance pulsed-power accelerators (Z300 and Z800) based on linear-transformer-driver technology have been designed [W. A. Stygar et al., Phys. Rev. ST Accel. Beams 18, 110401 (2015)]. The Z300 design would provide 48 MA to a MagLIF load, while Z800 would provide 65 MA. Parameterized Thevenin-equivalent circuits were used to drive a series of 1D and 2D numerical MagLIF simulations with currents ranging from what Z can deliver now to what could be achieved by these conceptual future pulsed-power accelerators. 2D simulations of simple MagLIF targets containing just gaseous DT have yields of 18 MJ for Z300 and 440 MJ for Z800. The 2D simulated yield for Z800 is increased to 7 GJ by adding a layer of frozen DT ice to the inside of the liner.« less

Ultra-broad polypyrrole (PPy) nano-ribbons seeded by racemic surfactants aggregates and their high-performance electromagnetic radiation elimination.

PubMed

Jiao, Yingzhi; Wu, Fan; Zhang, Kun; Sun, Mengxiao; Xie, Aming; Dong, Wei

2017-08-04

Ribbon-like nano-structures possess high aspect ratios, and thus have great potential in the development of high-performance microwave absorption (MA) materials that can effectively eliminate adverse electromagnetic radiation. However, these nano-structures have been scarcely constructed in the field of MA, because of the lack of efficient synthetic routes. Herein, we developed an efficient method to successfully construct polypyrrole (PPy) nano-ribbons using the self-assembly aggregates of a racemic surfactant as the seeds. The frequency range with a reflection loss value of lower than -10 dB reached 7.68 GHz in the frequency range of 10.32-18.00 GHz, and surpassed all the currently reported PPy nano-structures, as well as most other MA nano-materials. Through changing the amount of surfactant, both the nano-structures and MA performance can be effectively regulated. Furthermore, the reason behind the high-performance MA of PPy nano-ribbons has been deeply explored. It opens up the opportunity for the application of conducting polymer nano-ribbons as a lightweight and tunable high-performance MA material, especially in applications of special aircraft and flexible electronics.

Baleen boom and bust: a synthesis of mysticete phylogeny, diversity and disparity

PubMed Central

Marx, Felix G.; Fordyce, R. Ewan

2015-01-01

A new, fully dated total-evidence phylogeny of baleen whales (Mysticeti) shows that evolutionary phases correlate strongly with Caenozoic modernization of the oceans and climates, implying a major role for bottom-up physical drivers. The phylogeny of 90 modern and dated fossil species suggests three major phases in baleen whale history: an early adaptive radiation (36–30 Ma), a shift towards bulk filter-feeding (30–23 Ma) and a climate-driven diversity loss around 3 Ma. Evolutionary rates and disparity were high following the origin of mysticetes around 38 Ma, coincident with global cooling, abrupt Southern Ocean eutrophication and the development of the Antarctic Circumpolar Current (ACC). Subsequently, evolutionary rates and disparity fell, becoming nearly constant after approximately 23 Ma as the ACC reached its full strength. By contrast, species diversity rose until 15 Ma and then remained stable, before dropping sharply with the onset of Northern Hemisphere glaciation. This decline coincided with the final establishment of modern mysticete gigantism and may be linked to glacially driven variability in the distribution of shallow habitats or an increased need for long-distance migration related to iron-mediated changes in glacial marine productivity. PMID:26064636

Baleen boom and bust: a synthesis of mysticete phylogeny, diversity and disparity.

PubMed

Marx, Felix G; Fordyce, R Ewan

2015-04-01

A new, fully dated total-evidence phylogeny of baleen whales (Mysticeti) shows that evolutionary phases correlate strongly with Caenozoic modernization of the oceans and climates, implying a major role for bottom-up physical drivers. The phylogeny of 90 modern and dated fossil species suggests three major phases in baleen whale history: an early adaptive radiation (36-30 Ma), a shift towards bulk filter-feeding (30-23 Ma) and a climate-driven diversity loss around 3 Ma. Evolutionary rates and disparity were high following the origin of mysticetes around 38 Ma, coincident with global cooling, abrupt Southern Ocean eutrophication and the development of the Antarctic Circumpolar Current (ACC). Subsequently, evolutionary rates and disparity fell, becoming nearly constant after approximately 23 Ma as the ACC reached its full strength. By contrast, species diversity rose until 15 Ma and then remained stable, before dropping sharply with the onset of Northern Hemisphere glaciation. This decline coincided with the final establishment of modern mysticete gigantism and may be linked to glacially driven variability in the distribution of shallow habitats or an increased need for long-distance migration related to iron-mediated changes in glacial marine productivity.

Ultra-broad polypyrrole (PPy) nano-ribbons seeded by racemic surfactants aggregates and their high-performance electromagnetic radiation elimination

NASA Astrophysics Data System (ADS)

Jiao, Yingzhi; Wu, Fan; Zhang, Kun; Sun, Mengxiao; Xie, Aming; Dong, Wei

2017-08-01

Ribbon-like nano-structures possess high aspect ratios, and thus have great potential in the development of high-performance microwave absorption (MA) materials that can effectively eliminate adverse electromagnetic radiation. However, these nano-structures have been scarcely constructed in the field of MA, because of the lack of efficient synthetic routes. Herein, we developed an efficient method to successfully construct polypyrrole (PPy) nano-ribbons using the self-assembly aggregates of a racemic surfactant as the seeds. The frequency range with a reflection loss value of lower than -10 dB reached 7.68 GHz in the frequency range of 10.32-18.00 GHz, and surpassed all the currently reported PPy nano-structures, as well as most other MA nano-materials. Through changing the amount of surfactant, both the nano-structures and MA performance can be effectively regulated. Furthermore, the reason behind the high-performance MA of PPy nano-ribbons has been deeply explored. It opens up the opportunity for the application of conducting polymer nano-ribbons as a lightweight and tunable high-performance MA material, especially in applications of special aircraft and flexible electronics.

mA beam acceleration efforts on 100 MeV H- cyclotron at CIAE

NASA Astrophysics Data System (ADS)

Zhang, Tianjue; An, Shizhong; Lv, Yinlong; Ge, Tao; Jia, Xianlu; Ji, Bin; Yin, Zhiguo; Pan, Gaofeng; Cao, Lei; Guan, Fengping; Yang, Jianjun; Li, Zhenguo; Zhao, Zhenlu; Wu, Longcheng; Zhang, He; Wang, Jingfeng; Zhang, Yiwang; Liu, Jingyuan; Li, Shiqiang; Lu, Xiaotong; Liu, Zhenwei; Li, Yaoqian; Guo, Juanjuan; Cao, Xuelong; Guan, Leilei; Wang, Fei; Wang, Yang; Yang, Guang; Zhang, Suping; Hou, Shigang; Wang, Feng

2017-09-01

Various technologies for high current compact H- cyclotron have been developed at CIAE since 1990s. A 375 μA proton beam was extracted from a 30 MeV compact H- cyclotron CYCIAE-30 at the end of 1994. A central region model cyclotron CYCIAE-CRM was developed for the design verification of a 100 MeV high current compact H- cyclotron CYCIAE-100. It is also a 10 MeV proton machine as a prototype for PET application. A 430 μA beam was achieved in 2009. The first beam was extracted from the CYCIAE-100 cyclotron on July 4, 2014, the operation stability has been improved and beam current has been increased gradually. A 1.1 mA proton beam was measured on the internal target in July 2016. The effort for an increasing of proton beam has continued till now. In this paper, the effort on several aspects for mA beam development will be presented, including the multi-cusp source, buncher, matching from the energy of the injected beam, vertical beam line and central region, beam loading of the RF system and instrumentation for beam diagnostics etc.

Simultaneous Perforation and Doping of Si Nanoparticles for Lithium-Ion Battery Anode.

PubMed

Lv, Guangxin; Zhu, Bin; Li, Xiuqiang; Chen, Chuanlu; Li, Jinlei; Jin, Yan; Hu, Xiaozhen; Zhu, Jia

2017-12-27

Silicon nanostructures have served as promising building blocks for various applications, such as lithium-ion batteries, thermoelectrics, and solar energy conversions. Particularly, control of porosity and doping is critical for fine-tuning the mechanical, optical, and electrical properties of these silicon nanostructures. However, perforation and doping are usually separated processes, both of which are complicated and expensive. Here, we demonstrate that the porous nano-Si particles with controllable dopant can be massively produced through a facile and scalable method, combining ball-milling and acid-etching. Nano-Si with porosity as high as 45.8% can be achieved with 9 orders of magnitude of conductivity changes compared to intrinsic silicon. As an example for demonstration, the obtained nano-Si particles with 45.8% porosity and 3.7 atom % doping can serve as a promising anode for lithium-ion batteries with 2000 mA h/g retained over 100 cycles at the current density of 0.5 C, excellent rate performance with 1600 mA h/g at the current density of 5 C, and a stable cycling performance of above 1500 mA h/g retained over 940 cycles at the current density of 1 C with carbon coating.

A new oxyfluorinated titanium phosphate anode for a high-energy lithium-ion battery.

PubMed

Ma, Zhaohui; Sun, Chunwen; Lyu, Yingchun; Wang, Yuesheng; Kim, Youngsik; Chen, Liquan

2015-01-21

Na3[Ti2P2O10F] was synthesized by a hydrothermal method. It has an open framework structure consisting of TiFO5 octahedra and PO4 tetrahedra. The feasibility of Na3[Ti2P2O10F] as an anode material for lithium-ion batteries was first studied. Na3[Ti2P2O10F] exhibits a reversible capacity of more than 200 mAh g(-1) at a discharge/charge current rate of 20 mA g(-1) (∼0.1 C) and 105 mA g(-1) at a discharge/charge current rate of 400 mA g(-1) (∼2 C) with a lower intercalation voltage. The result of in situ X-ray diffraction test shows the structural evolution during the first discharge/charge cycle. The structure of Na3[Ti2P2O10F] was kept during discharge/charge with a slight change of the lattice parameters, which indicates a lithium solid solution behavior.